Endangered and Threatened Wildlife and Plants; Emergency Listing of the Miami Blue Butterfly as Endangered, and Emergency Listing of the Cassius Blue, Ceraunus Blue, and Nickerbean Blue Butterflies as Threatened Due to Similarity of Appearance to the Miami Blue Butterfly, 49542-49567 [2011-19812]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 154 (Wednesday, August 10, 2011)]
[Rules and Regulations]
[Pages 49542-49567]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-19812]



[[Page 49541]]

Vol. 76

Wednesday,

No. 154

August 10, 2011

Part II





Department of the Interior





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Fish & Wildlife Services





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; Emergency Listing of the 
Miami Blue Butterfly as Endangered, and Emergency Listing of the 
Cassius Blue, Ceraunus Blue, and Nickerbean Blue Butterflies as 
Threatened Due to Similarity of Appearance to the Miami Blue Butterfly; 
Final Rule

Federal Register / Vol. 76 , No. 154 / Wednesday, August 10, 2011 / 
Rules and Regulations

[[Page 49542]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2011-0043 MO 92210-0-0008
RIN 1018-AX83


Endangered and Threatened Wildlife and Plants; Emergency Listing 
of the Miami Blue Butterfly as Endangered, and Emergency Listing of the 
Cassius Blue, Ceraunus Blue, and Nickerbean Blue Butterflies as 
Threatened Due to Similarity of Appearance to the Miami Blue Butterfly

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Emergency rule.

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SUMMARY: We, the Fish and Wildlife Service (Service), exercise our 
authority pursuant to section 4(b)(7) of the Endangered Species Act of 
1973, as amended (Act), to emergency list the Miami blue butterfly 
(Cyclargus thomasi bethunebakeri) as endangered. This subspecies is 
currently known to occur at only a few small remote islands within the 
Florida Keys. Current population numbers are not known, but are 
estimated in the hundreds of butterflies. We are also emergency listing 
the cassius blue butterfly (Leptotes cassius theonus), ceraunus blue 
butterfly (Hemiargus ceraunus antibubastus), and nickerbean blue 
butterfly (Cyclargus ammon) as threatened due to similarity of 
appearance to the Miami blue, with a special rule pursuant to section 
4(d) of the Act.
    Due to the subspecies' severe reduction in geographic range, small 
population sizes, and imminent threats, we need to make protective 
measures afforded by the Act available to the Miami blue immediately. 
This emergency rule provides Federal protection pursuant to the Act for 
a period of 240 days. A proposed rule to list the Miami blue butterfly 
as endangered and to list the cassius blue butterfly, ceraunus blue 
butterfly, and nickerbean blue butterfly as threatened due to 
similarity of appearance to the Miami blue is published concurrently 
with this emergency rule, and it can be found in this issue of the 
Federal Register in the Proposed Rules section.

DATES: This emergency rule becomes effective on August 10, 2011, and 
expires April 6, 2012.

ADDRESSES: The supporting information used in this emergency rulemaking 
is available for inspection, by appointment, during normal business 
hours at the U.S. Fish and Wildlife Service, South Florida Ecological 
Services Office, 1339 20th Street, Vero Beach, Florida 32960-3559.

FOR FURTHER INFORMATION CONTACT: Paula Halupa, Fish and Wildlife 
Biologist, U.S. Fish and Wildlife Service, South Florida Ecological 
Services Office, 1339 20th Street, Vero Beach, Florida 32960-3559 by 
telephone 772-562-3909, ext. 257 or by electronic mail: 
miamiblueinfo@fws.gov.

SUPPLEMENTARY INFORMATION:

Background

    The Miami blue is a small, brightly colored butterfly approximately 
0.8 to 1.1 inches (1.9 to 2.9 centimeters [cm]) in length (Pyle 1981, 
p. 488) with a forewing length of 0.3 to 0.5 inches (8.0 to 12.5 
millimeters) (Minno and Emmel 1993, p. 134). Wings of males are blue 
above (dorsally), with a narrow black outer border and white fringes; 
females are bright blue dorsally, with black borders and an orange/red 
and black eyespot near the anal angle of the hindwing (Comstock and 
Huntington 1943, p. 98; Minno and Emmel 1993, p. 134). The underside is 
grayish with darker markings outlined with white and bands of white 
wedges near the outer margin. The ventral hindwing has two pairs of 
eyespots, one of which is capped with red; basal and costal spots on 
the hindwing are black and conspicuous (Minno and Emmel 1993, p. 134). 
The winter (dry season) form is much lighter blue than the summer (wet 
season) form and has narrow black borders (Opler and Krizek 1984, p. 
112). Seasonal wing pattern variation may be caused by changes in 
humidity, temperature, or length of day (Pyle 1981, p. 489). Miami blue 
larvae are bright green with a black head capsule, and pupae vary in 
color from black to brown (Minno and Emmel 1993, pp. 134-135).
    The Miami blue is similar in appearance to three other sympatric 
(occupying the same or overlapping geographic areas without 
interbreeding) butterflies that occur roughly in the same habitats: 
cassius blue (Leptotes cassius theonus), ceraunus blue (Hemiargus 
ceraunus antibubastus), and nickerbean blue (Cyclargus ammon). The 
Miami blue is slightly larger than the ceraunus blue (Minno and Emmel 
1993, p. 134), but the ceraunus blue has a different ventral pattern 
and flies close to the ground in open areas (Minno and Emmel 1994, p. 
647). The cassius blue often occurs with the Miami blue, but has dark 
bars rather than spots on the undersides of the wings (Minno and Emmel 
1994, p. 647). The Miami blue can be distinguished from the ceraunus 
blue and cassius blue by its very broad white ventral submarginal band, 
the dorsal turquoise color of both sexes, and the orange-capped 
marginal eyespot on the hind wings (Opler and Krizek 1984, p. 112). The 
nickerbean blue is also similar to the Miami blue in general appearance 
but is considerably smaller; it has three black spots across the basal 
hindwing, while the Miami blue has four (Calhoun et al. 2002, p. 15). 
The larvae and pupae of the nickerbean blue closely resemble the Miami 
blue (Calhoun et al. 2002, p. 15).
    In a comparison of Miami blue butterfly specimens within the 
Florida Museum of Natural History (FLMNH) collection, Saarinen (2009, 
pp. 42-43) found a significant difference in wing chord length between 
males and females, with males having shorter wing chords than females. 
However, no significant differences were found between wing chord 
length in comparing wet and dry seasons, decade of collection, seven 
different regions, or between eastern mainland and Keys specimens 
(Saarinen 2009, pp. 42-43). No seasonal size differences were found 
between the mainland populations and those in the Keys (Saarinen 2009, 
p. 43).
    In a comparison of body size in a recent Miami blue population 
(BHSP 2002-2006), females were significantly larger than males, and 
individuals sampled in the wet season were also significantly larger 
than in the dry season (Saarinen 2009, p. 43). In a comparison of 
recent Bahia Honda State Park (BHSP) individuals with specimens from 
historical collections (FLMNH data), BHSP individuals were 
significantly larger than historical specimens, females from BHSP were 
also significantly larger than historical female specimens, and BHSP 
adults measured in wet seasons were larger than those sampled in wet 
seasons in museum collections (Saarinen 2009, p. 43). Saarinen (2009, 
p. 47) suggested that perhaps larger adults were selected for over time 
with larger adults being more capable of dispersing and finding food 
and mates. Limited food resources during larval development or abrupt 
termination of availability of food in the last larval instar can lead 
to early pupation and a smaller adult size (T.C. Emmel, pers. comm., as 
cited in Saarinen 2009, p. 47). It is possible that differences in host 
plant (e.g., nutrition) and age of specimens (e.g., freshness) may also 
be factors when comparing body size between recent specimens and those 
from historical collections.

[[Page 49543]]

Taxonomy

    The Miami blue belongs to the family Lycaenidae (Leach), subfamily 
Polyommatinae (Swainson). The species Hemiargus thomasi was originally 
described by Clench (1941, pp. 407-408), and the subspecies Hemiargus 
thomasi bethunebakeri was first described by Comstock and Huntington 
(1943, p. 97). Although some authors continue to use Hemiargus, Nabokov 
(1945, p. 14) instituted Cyclargus for some species, which has been 
supported by more recent research (Johnson and Balint 1995, pp. 1-3, 8-
11, 13; Calhoun et al. 2002, p. 13; K. Johnson, Florida State 
Collection of Arthropods, in litt. 2002). There are differences in the 
internal genitalic structures of the genera Hemiargus and Cyclargus 
(Johnson and Balint 1995, pp. 2-3, 11; K. Johnson, in litt. 2002). Kurt 
Johnson (in litt. 2002), who has published most of the existing 
literature since 1950 on the blue butterflies of the tribe 
Polyommatini, reaffirmed that thomasi belongs in the genus Cyclargus 
(Nabokov 1945, p. 14), not Hemiargus. Accordingly, Cyclargus thomasi 
bethunebakeri (Pelham 2008, p. 256) and its taxonomic standing is 
accepted (Integrated Taxonomic Information System 2011, p. 1).
    In 2003, questions about the taxonomic identity of Miami blues from 
BHSP were raised by a few individuals. To address these questions, the 
Service sent two pairs (male and female) of adult specimens to three 
independent taxonomists/reviewers (Dr. Jacqueline Miller, Associate 
Curator, Allyn Museum of Entomology (AME), FLMNH; Dr. Paul Opler, 
Colorado State University; and John Calhoun, Museum of Entomology, 
Florida State Collection of Arthropods) for verification. To avoid harm 
to the wild population, scientists examined moribund adults from a 
captive colony generated from individuals taken from BHSP. Each 
reviewer independently confirmed through various means (e.g., 
comparison with confirmed specimens, dissection and examination of 
genitalia) that the identities of the adult specimens examined were 
Cyclargus thomasi bethunebakeri (J. Miller, in litt. 2003; P. Opler, in 
litt. 2003; J. Calhoun, in litt. 2003a). We received an additional 
confirmation from Lee Miller, Curator (AME, FLMNH) stating that the 
identities of the adult specimens examined were Cyclargus thomasi 
bethunebakeri (L. Miller, in litt. 2003). Taxonomic verification by 
genitalic dissection of the Miami blue at Key West National Wildlife 
Refuge (KWNWR) has not occurred, but preliminary molecular evidence has 
confirmed that they are the same taxon (E.V. Saarinen, unpub. data, as 
cited in Saarinen 2009, p. 18).

Life History

    Like all butterflies, the Miami blue undergoes complete 
metamorphosis, with four life stages (egg, caterpillar or larva, pupa 
or chrysalis, and adult). The generation time is approximately 30-40 
days (Carroll and Loye 2006, p. 19; Saarinen 2009, p. 22, 76). Although 
a single Miami blue female can lay 300 eggs, high mortality may occur 
in the immature larval stages prior to adulthood (T. Emmel, University 
of Florida [UF], pers. comm. 2002). Reported host plants are blackbead 
(Pithecellobium spp.), nickerbean (Caesalpinia spp.), balloonvine 
(Cardiospermum spp.), and presumably Acacia spp. (Kimball 1965, p. 49; 
Lenczewski 1980, p. 47; Pyle 1981, p. 489; Opler and Krizek 1984, p. 
113; Minno and Emmel 1993, p. 134; Calhoun et al. 2002, p. 18; Cannon 
et al. 2010, p. 851). In addition, Rutkowski (1971, p. 137) observed a 
female laying one egg just above the lateral bud on snowberry 
(Chiococca alba). Eggs are laid singly near the base of young pods or 
just above the lateral buds of balloonvine and the flowers of 
leguminous trees (Opler and Krizek 1984, p. 113; Minno and Emmel 1993, 
p. 134); flower buds and young tender leaves of legumes are preferred 
(Minno and Minno 2009, p. 78; M. Minno, pers. comm. 2010).
    On nickerbean (Caesalpinia spp.), females lay eggs on developing 
shoots, foliage, and flower buds (Saarinen 2009, p. 22). Oviposition 
occurs throughout the day with females often seeking terminal growth 
close to the ground (< 3.3 feet [< 1 meter]) or in locations sheltered 
from the wind (Emmel and Daniels 2004, p. 13). Eggs are generally laid 
singly, but may be clustered on developing leaves, shoot tips, and 
flower buds (Saarinen 2009, p. 22). After several days of development, 
larvae chew out of eggs and develop through four instar stages, with 
total larval development time lasting 3 to 4 weeks, depending upon 
temperature and humidity (Saarinen 2009, p. 22). Fourth instar larvae 
pupate in sheltered or inconspicuous areas, often underneath leaf 
whorls or bracts (Saarinen 2009, p. 22). Adult butterflies eclose 
(emerge) after 5 to 8 days, depending on temperature and humidity 
(Saarinen 2009, p. 22).
    On blackbead plants, females lay eggs on flower buds and emerging 
leaves (Cannon et al. 2010, p. 851). Oviposition on, or larval 
consumption of, mature blackbead leaves was not observed (Cannon et al. 
2010, p. 851). Thus, Cannon et al. (2010, p. 851) suggest that 
abundance may be limited by the availability of young blackbead leaves 
and buds for egg-laying, even if abundant suitable nectar sources (see 
Habitat) are available year-round.
    On balloonvine, females lay single eggs near fruit (capsules) 
(Carroll and Loye 2006, p. 18). Newly hatched larvae chew distinctive 
holes through the outer walls of the capsules to access seeds (Minno 
and Emmel 1993, p. 134). After consuming seeds within the natal 
capsule, larvae must crawl to a sequence of two or three balloons 
before growing large enough to pupate. Attending ants follow through 
the same holes (see Interspecific relationships below). Miami blues 
were also observed to commonly pupate within mature capsules (sometimes 
with ants in attendance within the capsule) (Carroll and Loye 2006, p. 
20).
    The Miami blue has been described as having multiple, overlapping 
broods year-round (Pyle 1981, p. 489). Adults can be found every month 
of the year (Opler and Krizek 1984, pp. 112-113; Minno and Emmel 1993, 
p. 135; 1994, p. 647; Emmel and Daniels 2004, p. 9; Saarinen 2009, p. 
22). Opler and Krizek (1984, pp. 112-113) indicated one long winter 
generation from December to April, during which time the adults are 
probably in reproductive diapause (a period in which growth, 
development, and physiological activity is suspended or diminished); a 
succession of shorter generations was thought to occur from May through 
November, the exact number of which is unknown. Glassberg et al. (2000, 
p. 79) described the Miami blue as having occurred all year, with three 
or more broods. Researchers have noted a marked decrease of adults from 
December to early February at BHSP, indicative of a short diapause 
(Emmel and Daniels 2003, p. 3; 2004, p. 9). Saarinen also noted that 
the life cycle at BHSP slowed in winter months and suspected a slight 
diapause (E.V. Saarinen and J.C. Daniels, unpub. data, as cited in 
Saarinen 2009, p. 22). Conversely, Minno (pers. comm. 2010) notes that 
there have been records of adults in December and January and suggests 
that this tropical butterfly may not have a winter diapause, but 
rather, emergence may be delayed by cold temperatures in some years. 
Salvato and Salvato (2007, p. 163) and Cannon et al. (2010, pp. 849-
850) also reported numerous adults at BHSP and KWNWR, respectively, 
during winter months.
    Information on adult lifespan is limited. Adults may live a maximum 
of 9 days, but most adults live only a few

[[Page 49544]]

days (J. Daniels, UF, pers. comm. 2003a, 2003b). In general, adult 
butterflies survive less than a week in the wild; there are 
approximately 8-10 generations per year (Saarinen et al. 2009a, p. 31). 
Generations are not completely discrete due to the variance in 
development time of all life stages (Saarinen et al. 2009a, p. 31).
    Range size and dispersal--Adult Miami blues are nonmigratory and 
appear to be very sedentary (Emmel and Daniels 2004, p. 6). Based on 
mark-recapture work conducted in 2002-2003, recaptured adults (N=39) 
moved an average of 6.53 +/- 11.68 feet (2.0 +[sol]- 3.6 meters), four 
individuals moved between 25 and 50 feet (7.6 and 15.2 meters), and 
only three individuals moved more than 50 feet (15.2 meters) over a few 
days (Emmel and Daniels 2004, pp. 6, 32-38). Few individuals were found 
to move between the lower and upper walkway locations of the south end 
colony sites at BHSP (approximately 100 feet [30.5 meters]); no 
movement between any of the smaller individual, isolated colony sites 
was recorded (Emmel and Daniels 2004, p. 6). However, Saarinen (2009, 
pp. 73, 78-79) found that genetic exchange between colonies occurred at 
BHSP and noted that small habitat patches may be crucial in providing 
links between subpopulations in an area.
    Interspecific relationships--As in many lycaenids worldwide (Pierce 
et al. 2002, p. 734), Miami blue larvae associate with ants (Emmel 
1991, p. 13; Minno and Emmel 1993, p. 135; Carroll and Loye 2006, pp. 
19-20) in at least four genera of ants in three subfamilies of 
Formicidae (Saarinen and Daniels 2006, p. 71; Saarinen 2009, p. 131, 
133). Miami blues using nickerbean at BHSP and Everglades National Park 
(ENP) (reintroduced individuals) were variously tended by Camponotus 
floridanus, C. planatus, Crematogaster ashmeadi, Forelius pruinosus, 
and Tapinoma melanocephalum (Saarinen and Daniels 2006, p. 71; Saarinen 
2009, pp. 131, 138). C. floridanus was the primary ant symbiont, 
commonly found tending larvae; other ant species were encountered less 
often (Saarinen and Daniels 2006, p. 70; Saarinen 2009, pp. 131-132). 
Liquid (honeydew) exuded from the butterfly's dorsal nectary organ 
(honey gland) was actively imbibed by all species of ants (Saarinen and 
Daniels 2006, p. 70; Saarinen 2009, p. 132).
    Late Miami blue instars were always found in association with ants, 
but early instars, prepupae, and pupae were frequently found without 
ants present (Saarinen and Daniels 2006, p. 70). Forelius pruinosus and 
Tapinoma melanocephalum were observed to derive honeydew from Miami 
blues they tended, but were not observed to actively protect them from 
any predator (Saarinen and Daniels 2006, p. 71; Saarinen 2009, p. 133). 
However, the presence of ants in the vicinity of larvae may potentially 
deter predators (Saarinen and Daniels 2006, pp. 71, 73; Saarinen 2009, 
p. 133, Trager and Daniels 2009, p. 480). Two additional ants, 
Paratrechina longicornis and P. bourbonica, have been identified as 
potential associates of the Miami blue (Saarinen and Daniels 2006, pp. 
70-71; Saarinen 2009, pp. 131, 138). P. longicornis was found near 
Miami blue larvae and appeared to tend them during brief encounters; P. 
bourbonica tended another lycaenid, martial scrub-hairstreak (Strymon 
martialis) at BHSP (Saarinen and Daniels 2006, p. 70). Cannon et al. 
(2007, p. 16) also observed two ant species attending Miami blues on 
KWNWR. Based on photographs, the ants appeared to be C. inaequalis and 
P. longicornis. C. planatus was observed on blackbead.
    In the 1980s, Miami blue larvae that fed on balloonvine in the 
upper Keys were also tended by ants (C. floridanus and C. planatus) 
(Carroll and Loye 2006, pp. 19-20). Carroll and Loye (2006, p. 20) 
found that Camponotus spp. raised with Miami blue larvae lived longer 
than ants raised with larvae of other lycaenid species or without any 
food source, demonstrating that larval secretions benefit ants.
    More recently, Trager and Daniels (2009, p. 479) most commonly 
found C. floridanus and C. planatus associated with wild and recently 
released Miami blue larvae. In a comparison of Miami blue larvae raised 
with and without ants, no effect of ant presence was found on any 
measurements of larval performance (e.g., age at pupation, pupal mass, 
length of pupation, total time as an immature) (Trager and Daniels 
2009, p. 480). Miami blue larval development was found to be similar to 
that of other conspecific lycaenid species not tended by ants (Trager 
and Daniels 2009, p. 480). Although the relationships are not 
completely understood, it appears that Miami blue larvae may receive 
some benefits from tending ants (e.g., potential defense from 
predators) without much, if any, costs incurred.

Habitat

    The Miami blue is a coastal butterfly reported to occur in openings 
and around the edges of hardwood hammocks (forest habitats 
characterized by broad-leaved evergreens), and in other communities 
adjacent to the coast that are prone to frequent natural disturbances 
(e.g., coastal berm hammocks, dunes, and scrub) (Opler and Krizek 1984, 
p. 112; Minno and Emmel 1994, p. 647; Emmel and Daniels 2004, p. 12). 
It also uses tropical pinelands (Minno and Emmel 1993, p. 134) and open 
sunny areas along trails (Pyle 1981, p. 489). In the Keys, it was most 
abundant near disturbed hammocks where weedy flowers provided nectar 
(Minno and Emmel 1994, p. 647). It also occurred in pine rocklands 
(fire-dependent slash pine community with palms and a grassy 
understory) on Big Pine Key (Minno and Emmel 1993, p. 134; Calhoun et 
al. 2002, p. 18) and elsewhere in Monroe and Miami-Dade Counties. In 
Miami-Dade County, it occurred locally inland, sometimes in abundance 
(M. Minno, pers. comm. 2010). Within KWNWR, all occupied areas had 
coastal strands and dunes fronted by beaches (Cannon et al. 2007, p. 
13; Cannon et al. 2010, p. 851).
    Larval host plants include blackbead, nickerbean, balloonvine, and 
presumably Acacia spp. (Dyar 1900, pp. 448-449, Kimball 1965, p. 49; 
Lenczewski 1980, p. 47; Pyle 1981, p. 489; Calhoun et al. 2002, p. 18). 
Gray nickerbean (Caesalpinia bonduc) is widespread and common in 
coastal south Florida. Following disturbances, it can dominate large 
areas (K. Bradley, The Institute for Regional Conservation [IRC], pers. 
comm. 2002). Gray nickerbean has been recorded as far north as Volusia 
County on the east coast, matching the historical range of the Miami 
blue, and Levy County on the west coast (J. Calhoun, pers. comm. 
2003b). The Miami blue is also reported to use peacock flower 
(Caesalpinia pulcherrima) (Matteson 1930, pp. 13-14; Calhoun et al. 
2002, p. 18), a widely cultivated exotic that occurs in disturbed 
uplands and gardens (Gann et al. 2001-2010, p. 1). Rutkowski (1971, p. 
137) and Opler and Krizek (1984, p. 113) reported the use of snowberry. 
Brewer (1982, p. 22) reported the use of cat's paw blackbead 
(Pithecellobium unguis-cati) on Sanibel Island in Lee County.
    Prior to the 1970s, documented host plants for the butterfly were 
nickerbean and blackbead (J. Calhoun, pers. comm. 2003b). Balloonvine 
(Cardiospermum spp.) was not reported as a host plant until the 1970s, 
when these plants seemed to have become common in extreme southern 
Florida (J. Calhoun, pers. comm. 2003b). Subsequently, balloonvine 
(Cardiospermum halicacabum), an exotic species in Florida, was the most 
frequently reported host plant for Miami blue (e.g., Lenczewski 1980, 
p. 47; Opler and Krizek 1984, p. 113; Minno and Emmel

[[Page 49545]]

1993, p. 134; 1994, p. 647; Calhoun et al. 2002, p. 18). However, 
Carroll and Loye (2006, pp. 13-15) corrected ``the common view that a 
principal host plant, balloonvine, is an exotic weed.'' They found that 
published reports of Miami blue larvae on balloonvine all identified 
the host as C. halicacabum and stated that the butterfly was instead 
dependent upon a declining native C. corindum (Carroll and Loye 2006, 
pp. 14, 23). Bradley (pers. comm. 2002) also confirmed that C. 
halicacabum does not occur in the Keys, noting that the native 
balloonvine (C. corindum) is relatively common and widespread in the 
Keys and has been commonly mistaken as C. halicacabum in the Keys and 
other sites in south Florida.
    Calhoun (pers. comm. 2003b) suggested that the Miami blue may 
simply utilize whatever acceptable hosts are available under suitable 
conditions. According to Calhoun (pers. comm. 2003b), a review of the 
historical range of the butterfly and its host plants suggests 
balloonvine was a more recent larval host plant and temporarily 
surpassed nickerbean as the primary host plant. As native coastal 
habitats were destroyed, balloonvine readily invaded disturbed 
environments, and the Miami blue used what was most commonly available. 
Minno (pers. comm. 2010) suggested that the Miami blue used balloonvine 
on Key Largo and Plantation Key extensively in the 1970s through the 
1990s, noting that nickerbean, blackbead, and perhaps other hosts were 
also probably used, but not documented.
    The Miami blue metapopulation (series of small populations that 
have some level of interaction) at KWNWR was found to rely upon Florida 
Keys blackbead as the singular host plant (Cannon et al. 2007, p. 1; 
Cannon et al. 2010, pp. 851-852). Blackbead was also an important 
nectar plant when in flower. High counts of Miami blues at KWNWR were 
generally associated with the emergence of flowers and new leaves on 
blackbead (Cannon et al. 2007, pp. 14-15; Cannon et al. 2010, pp. 851-
852). All sites that supported Miami blues contained blackbead (Cannon 
et al. 2007, p. 6; Cannon et al. 2010, p. 851). Limited abundance of 
blackbead within select areas of KWNWR was thought to limit abundance 
of the Miami blue (Cannon et al. 2007, p. 10; Cannon et al. 2010, p. 
850). At BHSP, the Miami blue was closely associated with gray 
nickerbean, but also uses blackbead (M. Minno, pers. comm. 2010). In 
KWNWR, gray nickerbean was rare, with only a few small plants on Boca 
Grande Key and the Marquesas Keys (Cannon et al. 2010, p. 851).
    Adult Miami blues have been reported to feed on a wide variety of 
nectar sources including Spanish needles (Bidens alba), Leavenworth's 
tickseed (Coreopsis leavenworthi), scorpionstail (Heliotropium 
angiospermum), turkey tangle fogfruit or capeweed (Lippia nodiflora), 
buttonsage (Lantana involucrata), snow squarestem (Melanthera nivea [M. 
aspera]), blackbead, Brazilian pepper (Schinus terebinthifolius), false 
buttonweed (Spermacoce spp.), and seaside heliotrope (Heliotropium 
curassavicum) (Pyle 1981, p. 489; Opler and Krizek 1984, p. 113; Minno 
and Emmel 1993, p. 135; Emmel and Daniels 2004, p. 12). Emmel and 
Daniels (2004, p. 12) reported that the Miami blue uses a variety of 
flowering plant species in the Boraginaceae, Asteraceae, Fabaceae, 
Polygonaceae, and Verbenaceae families for nectar. Cannon et al. (2010, 
p. 851) found the butterfly uses nine plant species as nectar sources 
within KWNWR, including: Blackbead, snow squarestem, coastal searocket 
(Cakile lanceolata), black torch (Erithalis fruticosa), yellow joyweed 
(Alternanthera flavescens), bay cedar (Suriana maritime), sea lavender 
(Argusia gnaphalodes), seaside heliotrope, and sea purslane (Sesuvium 
portulacastrum).
    Nectar sources must be near potential host plants since the 
butterflies are sedentary and may not travel between patches of host 
and nectar sources (Emmel and Daniels 2004, p. 13). This may help 
explain the absence of the Miami blue from areas in which host plants 
are abundant and nectar sources are limited (J. Calhoun, pers. comm. 
2003b). Emmel and Daniels (2004, p. 13) argued that it is potentially 
critical that sufficient available adult nectar sources be directly 
adjacent to host patches and also important that a range of potential 
nectar sources be available in the event one plant species goes out of 
flower or is adversely impacted by environmental factors. Cannon et al. 
(2010, p. 851) suggested that the growth stage of blackbead, coupled 
with abundant nectar from herbaceous plants, likely influenced Miami 
blue abundance; the highest counts occurred when blackbead was 
flowering profusely and producing new leaves.

Historical Distribution

    The Miami blue butterfly (Cyclargus thomasi bethunebakeri) is 
endemic to Florida with additional subspecies occurring in the Bahamas, 
Puerto Rico, and Hispaniola (Smith et al. 1994, p. 129; Hernandez 2004, 
p. 100; Saarinen 2009, pp. 18-19, 28). Field guides and other sources 
differ as to whether C. thomasi bethunebakeri occurs in the Bahamas. 
Clench (1963, p. 250), who collected butterflies extensively in the 
West Indies, indicated that the subspecies occurred only in Florida. 
Riley (1975, p. 110) and Calhoun et al. (2002, p. 13) indicated that 
the Miami blue of Florida rarely occurs as a stray in the Bahamas. 
Minno and Emmel (1993, p. 134; 1994, p. 647) and Calhoun (1997, p. 46) 
considered the Miami blue to occur only in Florida (endemic to Florida, 
with other subspecies found in the Bahamas and Greater Antilles). Smith 
et al. (1994, p. 129) indicated that the Miami blue occurs in southern 
Florida, but noted it has been recorded from the Bimini Islands in the 
Bahamas. However, in a recent comprehensive study of museum specimens, 
Saarinen (2009, p. 28) found no specimens in current museum holdings to 
verify this. Overall, the majority of historical records pertaining to 
this subspecies' distribution are dominated by Florida occurrences, 
with any peripheral occurrences in the Bahamas possibly being ephemeral 
in nature.
    Although information on distribution is somewhat limited, it is 
clear that the historical range of the Miami blue has been 
significantly reduced. The type series (i.e., the original set of 
specimens on which the description of the species is based) contains 
specimens ranging from Key West up the east coast to Volusia County 
(Comstock and Huntington 1943, p. 98; J. Calhoun, pers. comm., 2003b). 
Opler and Krizek (1984, p. 112) showed its historical range as being 
approximately from Tampa Bay and Cape Canaveral southward along the 
coasts and through the Keys. It has also been collected in the Dry 
Tortugas (Forbes 1941, pp. 147-148; Kimball 1965, p. 49; Glassberg and 
Salvato 2000, p. 2). Lenczewski (1980, p. 47) noted that it was 
reported as extremely common in the Miami area in the 1930s and 1940s. 
Calhoun et al. (2002, p. 17) placed the historical limits of the 
subspecies' northern distribution at Hillsborough and Volusia Counties, 
extending southward along the coasts to the Marquesas Keys (west of Key 
West).
    The Miami blue was most common on the southern mainland and the 
Keys, especially Key Largo and Big Pine Key (Calhoun et al. 2002, p. 
17) and other larger keys with hardwood hammock (Monroe County) (M. 
Minno, pers. comm. 2010). The subspecies was recorded on at least 10 
islands of the Keys (Adams Key, Big Pine Key, Elliott Key, Geiger Key, 
Key Largo, Lignumvitae Key, Old Rhodes Key, Plantation Key, Stock 
Island, Sugarloaf Key) (Minno and Emmel 1993, p. 134). On the Gulf 
coast, it was reportedly

[[Page 49546]]

more localized and tended to occur on more southerly barrier islands 
(J. Calhoun, pers. comm. 2003b). According to Calhoun et al. (2002, p. 
17), the Miami blue occupied areas on the barrier islands of Sanibel, 
Marco, and Chokoloskee, along the west coast into the 1980s (based upon 
Brewer 1982, p. 22; Minno and Emmel 1994, pp. 647-648). Lenczewski 
(1980, p. 47) reported that the Miami blue historically occurred at 
Chokoloskee, Royal Palm (Miami-Dade County), and Flamingo (Monroe 
County) within ENP, but that the subspecies has not been observed in 
ENP since 1972.
    Based upon examination of specimens from museum collections 
(N=689), Saarinen (2009, pp. 42, 55-57) found a large, primarily 
coastal, geographic distribution for the butterfly. Most specimens from 
an 11-county area from 1900 to 1990 were collected in Miami-Dade and 
Monroe Counties (Saarinen 2009, pp. 42, 58). Records from Miami-Dade 
County (N=212) were most numerous in the 1930s and 1940s; records from 
Monroe County (N=387) (including all of the Florida Keys) were most 
numerous in the 1970s (Saarinen 2009, pp. 42, 58). Saarinen (2009, p. 
47) was not able to quantify issues of collector bias and noted that 
collecting restrictions, inaccessibility of certain islands, and 
targeted interest in certain areas, may have been factors influencing 
the relative abundance (and distribution) of specimens collected. For 
example, it is unclear whether Key Largo represented a ``central 
hotspot,'' a spot simply heavily visited by lepidopterists, or both 
(Saarinen 2009, p. 47). Still, it is clear that specimens were common 
in museum collections from the early 1900s to the 1980s, suggesting 
that the butterfly was abundant, at least in local patches, during this 
time period (Saarinen 2009, p. 46). This is consistent with the work of 
Carroll and Loye (2006, pp. 15-18), who, in a compilation of location 
data for specimens (N=209), found that most collections were from the 
Upper Keys; those from peripheral sites were generally less recent and 
only single specimens. Examination of museum records further verified 
the Miami blue's wide distribution in southern Florida through time 
(Carroll and Loye 2006, pp. 15-18; Saarinen 2009, p. 46).
    By the 1990s, very few Miami blue populations were known to 
persist, and the butterfly had not been seen on the western Florida 
coast since 1990, where it was last recorded on Sanibel Island (Calhoun 
et al. 2002, p. 17). One of the few verifiable reports (prior to 
rediscovery in 1999) was on Big Pine Key in March 1992 (Glassberg et 
al. 2000, p. 79; Glassberg and Salvato 2000, p. 1; Calhoun et al. 2002, 
p. 17). Following Hurricane Andrew in 1992, there were a few 
unsupported reports from Key Largo and Big Pine Key and the 
southeastern Florida mainland from approximately 1993 to 1998 
(Glassberg and Salvato 2000, p. 3; Calhoun et al. 2002, p. 17). In 
1996, four adult Miami blues were observed in the area of Dagny Johnson 
Key Largo Hammock Botanical State Park (DJSP) by Linda and Byrum Cooper 
(L. Cooper, listowner of LEPSrUS Web site, pers. comm. 2002; Calhoun et 
al. 2002, p. 17). However, a habitat restoration project apparently 
eradicated that population (L. Cooper, pers. comm. as cited in Calhoun 
et al. 2002, p. 17).
    The Miami blue was presumed to be extirpated until its rediscovery 
in 1999 by Jane Ruffin, who observed approximately 50 individuals at a 
site in the lower Keys (Bahia Honda) (Ruffin and Glassberg 2000, p. 3; 
Calhoun et al. 2002, p. 17). Additional individuals were located at a 
site within 0.5 mile (0.8 kilometers (km)) of where Ruffin had 
discovered the population (Glassberg and Salvato 2000, p. 3). Glassberg 
and Salvato (2000, p. 1) stated that more than 15 highly competent 
butterfly enthusiasts had failed to find any populations of the Miami 
blue from 1992 until 1999, despite more than 1,000 hours of search 
effort in all sites known to harbor former colonies and other potential 
sites throughout south Florida and the Keys. In May 2001, there was an 
additional sighting by Richard Gillmore of a single Miami blue in the 
hammocks in North Key Largo (Calhoun et al. 2002, p. 17; J. Calhoun, 
pers. comm. 2003b).

Current Distribution

    Numerous searches for the Miami blue have occurred in the past 
decade by various parties. The Miami blue was not observed on 105 
survey dates at 11 locations on the southern Florida mainland from 1990 
to 2002 (Edwards and Glassberg 2002, p. 4). In the Keys, surveys during 
the same time period also produced no sightings of the Miami blue at 29 
locations for 224 survey dates (Edwards and Glassberg 2002, p. 4). In 
2002, the Service initiated a status survey, contracting researchers at 
the UF, to search areas within the subspecies' historical range, 
concentrating on the extreme south Florida mainland and throughout the 
Keys. Despite surveys at 45 sites during 2002-2003, adults or immature 
stages were found only at a single site near BHSP on West Summerland 
Key (Emmel and Daniels 2004, pp. 3-6; 21-25) (approximately 1.9 miles 
[3 km] west of BHSP). The Miami blue was not found on the mainland, 
including Fakahatchee Strand, Charles Deering Estate, ENP, Marco 
Island, or Chokoloskee (Emmel and Daniels 2004, pp. 5-6, 25). It was 
also absent from the following locations in the Keys: Elliott, Old 
Rhodes, Totten, and Adams Key in Biscayne National Park (BNP) and Key 
Largo and Plantation Key in the Upper Keys; Lignumvitae, Lower 
Matecumbe, Indian, and Long Keys in the Middle Keys; and Little Duck, 
Missouri, Ohio, No Name, Big Pine, Ramrod, Little Torch, Wahoo, Cudjoe, 
Sugarloaf, and Stock Island in the Lower Keys (Emmel and Daniels 2004, 
pp. 3-5; 21-24).
    Based upon an additional independent survey in 2002, the Miami blue 
was also not found at 18 historical locations where it had previously 
been observed or collected in Monroe, Broward, Miami-Dade, and Collier 
Counties into the 1980s (D. Fine, unpub. data, pers. comm. 2002). These 
were: Cactus Hammock (Big Pine Key), County Road (Big Pine Key), Grassy 
Key, John Pennekamp Coral Reef State Park, Windley Key, Crawl Key, 
Stock Island, Plantation Key, and Lower Matecumbe Key in Monroe County; 
Hugh Taylor Birch State Park and Coral Springs in Broward County; 
Redlands, IFAS Station, Frog City, and Card Sound Road in Miami-Dade 
County; Marco Island and Fakahatchee Strand State Preserve in Collier 
County.
    In 2003, the Service contracted the North American Butterfly 
Association (NABA) to perform systematic surveys in south Florida and 
the Keys to identify all sites at which 21 targeted butterflies, 
including the Miami blue, could be found. Despite considerable survey 
effort (i.e., 187 surveys performed), the Miami blue was not located at 
any location except Bahia Honda (NABA 2005, pp. 1-7). In addition, the 
Miami blue was not present within the J.N. Ding Darling National 
Wildlife Refuge or on Sanibel-Captiva Conservation Foundation 
properties (both on Sanibel Island), during annual surveys conducted 
from 1998 to 2009 (M. Salvato, pers. comm. 2011a). Monthly or quarterly 
surveys of Big Pine Key, conducted from 1997 to 2010, failed to locate 
Miami blues (M. Salvato, pers. comm. 2011b). Minno and Minno (2009, pp. 
77, 123-193) failed to locate the subspecies during butterfly surveys 
throughout the Keys conducted from August 2006 to July 2009.
    Although two fifth-instar larvae were documented on West Summerland 
Key in November 2003, on unprotected land approximately 2.2 miles (3.6 
km) west of BHSP (Emmel and Daniels 2004, pp. 3, 24, 26), none have 
been seen there

[[Page 49547]]

since. According to Daniels (pers. comm. 2003c), an adult (or adults) 
was likely blown to this key from Bahia Honda by strong winds or was at 
least partially assisted by the wind.
    In November 2006, Miami blues were discovered on islands within 
KWNWR (Cannon et al. 2007, p. 2). This discovery was significant 
because it was a new, geographically separate population, and doubled 
the known number of metapopulations remaining (to 2). During the period 
from 1999 to 2009, the Miami blue was consistently found at BHSP 
(Ruffin and Glassberg 2000, p. 29; Edwards and Glassberg 2002, p. 9; 
Emmel and Daniels 2009, p. 4; Daniels 2009, p. 3). However, this 
population may now be extirpated. This leaves the islands within KWNWR 
as the only known locations of the subspecies.
    Overall, the Miami blue has undergone a substantial reduction in 
its historical range, with an estimated > 99 percent decline in area 
occupied (Florida Fish and Wildlife Conservation Commission [FWC] 2010, 
p. 11). In 2009, metapopulations existed at two main locations: BHSP 
and KWNWR, roughly 50 miles (80 km) apart. The metapopulation at BHSP 
is now possibly extirpated with the last adult documented in July 2010 
(A. Edwards, Florida Atlantic University, pers. comm. 2011). It is 
feasible that additional occurrences exist in the Keys, but these may 
be ephemeral and low in population number (Saarinen 2009, p. 143). In 
2010, the Service funded an additional study with UF to search remote 
areas for possible presence; this study is now underway. The subspecies 
was not located in limited surveys conducted in the Cape Sable area of 
ENP in March 2011 (P. Halupa, pers. obs. 2011; M. Minno, pers. comm. 
2011).

Bahia Honda State Park

    Bahia Honda is a small island at the east end of the lower Keys, 
approximately 7.0 miles (11.3 km) west of Vaca Key (Marathon) and 2.0 
miles (3.2 km) east of Big Pine Key. The amount of suitable habitat 
(habitat supporting larval host plants and adjacent adult nectar 
sources) within BHSP is approximately 1.5 acres (0.6 hectares [ha]). Of 
the suitable habitat available at BHSP, approximately 85 percent (1.3 
acres [0.5 ha]) was occupied by the Miami blue (Emmel and Daniels 2004, 
p. 12). The metapopulation comprised 13 distinct colonies, with the 
core comprising 3 or 4 colonies, located at the southwest end (Emmel 
and Daniels 2004, pp. 6, 27). This area contained the largest 
contiguous patch of host plants, although the size was estimated to be 
0.8 acres (0.32 ha) (Emmel and Daniels 2004, p. 12). The second largest 
colony occurred at the opposite (northeast) end of BHSP and was based 
solely on the presence of two to three small, isolated patches of 
nickerbean directly adjacent to an existing nature trail and parking 
area (Emmel and Daniels 2004, p. 6). The remaining colonies were 
isolated, with most occurring in close proximity to the main park road 
(Emmel and Daniels 2004, pp. 13, 27). Isolated colonies used very small 
patches of nickerbean (e.g., one was estimated to be 10 by 10 feet [3 
by 3 meters]) (Emmel and Daniels 2003, p. 3), often adjacent to paved 
roads (Emmel and Daniels 2004, pp. 6, 12, 27).

Key West National Wildlife Refuge

    Efforts to define the limits of the KWNWR metapopulation were 
conducted from November 2006 to July 2007 (Cannon et al. 2007, pp. 10-
11; 2010, p. 849). Miami blues were found in seven sites on five 
islands in the Marquesas Keys, approximately 12.2 miles (19.6 km) west 
of Key West, and on Boca Grande Key, approximately 11.8 miles (19 km) 
west of Key West (6.3 miles [10.1 km] east-southeast of the Marquesas 
Keys) (Cannon et al. 2007, pp. 1-24; 2010, pp. 847-848). The eight 
sites occupied by Miami blues ranged from approximately 0.25 to 37.10 
acres (0.1-15.0 ha) (Cannon et al. 2007, p. 6; 2010, p. 848). The 
combined amount of upland habitat of occupied sites (within KWNWR) was 
roughly 59 acres (23.8 ha) (Cannon et al. 2010, p. 848). Miami blues 
were not found on Woman Key, approximately 10.1 miles (16.2 km) west of 
Key West, or Man Key, approximately 6.8 miles (10.9 km) west of Key 
West; these sites had abundant nectar plants, but few host plants 
(Cannon et al. 2007, pp. 5, 12; 2010, pp. 848-850). In addition, the 
Miami blue was not found on six islands in the Great White Heron 
National Wildlife Refuge (GWHNWR); these sites contained limited 
amounts of, or were lacking, either host plants or nectar plants 
(Cannon et al. 2007, pp. 5, 12; 2010, pp. 847, 850-851).
    In a separate study, Daniels also found four of the sites 
previously occupied within KWNWR to support the Miami blue variously 
from 2008 to 2010 (Emmel and Daniels 2008, pp. 7-10; 2009, pp. 9-13; 
Daniels 2008, pp. 1-6; Daniels 2010, pp. 3-5; J. Daniels, pers. comm. 
2010a). Survey effort, however, was limited. Some previously occupied 
islands were not searched, and no new occupied areas were identified.
    Followup presence and absence surveys by KWNWR in 2009 showed that 
the Miami blue was present on two sites in the Marquesas, but not on 
Boca Grande (P. Cannon, pers. comm. 2010a). In 2010, similar surveys 
indicated that the Miami blue was present on Boca Grande and one site 
in the Marquesas; it was still not located on Woman Key (P. Cannon, 
pers. comm. 2010b; T. Wilmers, pers. comm. 2010a). In March and April 
2011, Miami blues were still present on five of seven sites where 
previously found in KWNWR (T. Wilmers pers. comm. 2011a; N. Haddad, 
North Carolina State University [NCSU], pers. comm. 2011).

Reintroductions

    Although Miami blue butterflies were successfully reared in 
captivity, reintroductions have been unsuccessful. Since 2004, 
approximately 7,140 individuals have been released (J. Daniels pers. 
comm. as cited in FWC 2010, p. 8). Between August 2007 and November 
2008, reintroduction events were carried out at BNP and DJSP 12 times 
resulting in the release of 3,553 individuals (276 adults/3,277 larvae) 
(Emmel and Daniels 2009, p. 4). Monitoring efforts have been limited; 
19 days were spent monitoring reintroduction sites (Emmel and Daniels 
2009, p. 4). To date, no evidence of colony establishment has been 
found (Emmel and Daniels 2009, p. 4). It is not clear why 
reintroductions were unsuccessful. Numerous factors may have been 
involved (e.g., predation, parasitism, insufficient host plant or 
larval sources). Due to limited resources and other constraints, 
standard protocols were not employed to help identify factors that may 
have influenced reintroduction success. Research with surrogate species 
may be helpful to better establish protocols and refine techniques for 
the Miami blue prior to future propagation and reintroduction efforts.

Population Estimates and Status

Bahia Honda State Park metapopulation

    Prior to its apparent extirpation, the metapopulation at BHSP was 
monitored regularly from 2002 to 2009 (Emmel and Daniels 2009, p. 4). 
Pollard transects at the south-end colony site (largest) yielded annual 
peak counts of approximately 175, 84, 112, and 132, from 2002 to 2005 
(prior to hurricanes), and 82, 81, 120, and 38, from 2006 to 2009 
(Emmel and Daniels 2009, p. 4). From October 2002 to September 2003, 
abundance estimates using mark-release-recapture (Schnabel method) 
ranged from a low of 19.7 in February 2003 to a high of 114.5 in June 
2003

[[Page 49548]]

(Emmel and Daniels 2004, p. 9). Counts ranged from 6 to 100 adults 
during surveys by the NABA conducted from February 2004 to January 2005 
(NABA 2005, unpub. data). Monthly (2003 to 2006) or bimonthly (2007) 
monitoring by Salvato (pers. comm. 2011c) at the south-end colony 
produced annual average counts of 129, 58, 46, 6, and 8, respectively, 
from 2003 to 2007. Salvato (pers. comm. 2011c) observed 21, 10, and 0 
Miami blues from 2008 to 2010, respectively, based on limited surveys.
    In general, early (dry) season numbers were low in most years and 
were attributed to a persistent south Florida drought (Emmel and 
Daniels 2009, p. 4). Abundance trends indicated that there was a marked 
decrease in the number of individuals during the winter months 
(November to February) (Emmel and Daniels 2004, p. 9; 2009, p. 4). 
Higher abundances during the summer wet season may relate to production 
of a large quantity of new terminal growth on the larval host plants 
(nickerbean) and availability of nectar sources from spring rainfall 
(Emmel and Daniels 2004, pp. 9-11).
    Four hurricanes affected habitat at BHSP in 2005, resulting in 
reduced abundance of Miami blue following subsequent storms that 
continued throughout 2006 (Salvato and Salvato 2007, p. 160). Although 
no quantitative measures were taken, a significant portion of the 
nickerbean in the survey area (> 35 percent of the area of available 
habitat) was damaged by the storms; roughly 60-80 percent of the 
vegetation on the southern side of the island was visually estimated to 
have been heavily damaged, including large stands of host and nectar 
plants (Salvato and Salvato 2007, p. 156). Despite a decline in 
abundance after the hurricanes, the Miami blue had appeared to rebound 
toward pre-storm abundance by the summer months of 2007 (Salvato and 
Salvato 2007, p. 160). However, peaks remained below those found prior 
to the 2005 hurricane season (Emmel and Daniels 2009, p. 4).
    Although it is unclear when iguanas became established at BHSP, 
effects of herbivory on the host plant were apparent by late 2008 or 
early 2009 (Emmel and Daniels 2009, p. 4; Daniels 2009, p. 5; P. 
Cannon, pers. comm. 2009; A. Edwards, pers. comm. 2009; P. Hughes, 
pers. comm. 2009; M. Salvato, pers. comm. 2010a). Defoliation was 
mostly limited to the south-end colony site (Emmel and Daniels 2009, p. 
4). Cooperative eradication efforts to address this problem began in 
2009 and continue today; however, iguanas continue to impact terminal 
nickerbean growth (see Summary of Factors Affecting the Species) (Emmel 
and Daniels 2009, p. 4; Daniels 2009, p. 5; E. Kiefer, BHSP, pers. 
comm. 2011a). From 2006 through 2009, adult or immature Miami blues 
were found at several colony sites; however, one colony became 
relatively unproductive in 2005 (pre-hurricane) (Emmel and Daniels 
2009, p. 4). No Miami blues have been found at any roadway nickerbean 
patches within BHSP since 2005, prior to the advent of profound iguana 
herbivory and damages from hurricanes (Emmel and Daniels 2009, p. 4).
    The metapopulation has diminished in recent years likely due to the 
combined effects of small population size, drought, cold temperatures, 
and iguanas (see Summary of Factors Affecting the Species). In 2010, 
few Miami blues were observed at BHSP. On January 23, 2010, a 
photograph was taken of a pair of Miami blues mating (Olle 2010, p. 5). 
On February 12, 2010, a photograph was taken of a single adult (C. 
DeWitt, pers. comm. 2011). In March 2010, Daniels found one larva, but 
no adults (D. Cook, FWC, pers. comm. 2010a). In July 2010, a single 
adult was observed and photographed (A. Edwards, pers. comm. 2011). No 
Miami blue adults have been located during quarterly surveys conducted 
in 2010 by Salvato (pers. comm. 2010b, 2011c). No Miami blue 
butterflies of any life stage were subsequently seen despite frequent 
searches (D. Cook, pers. comm. 2010a; P. Cannon, pers. comm. 2010c, 
2010d, 2010e, 2010f; M. Salvato, pers. comm. 2011c, 2011d; Jim 
Duquesnel, BHSP, pers. comm. 2011a, 2011b).

Key West National Wildlife Refuge Metapopulation(s)

    The metapopulation at KWNWR yielded counts of several hundred, at 
various times, in 2006-2007. Checklist counting was used during surveys 
conducted between November 2006 and July 2007 to document the 
distribution and abundance of Miami blues (Cannon et al. 2007, p. 5; 
2010, p. 848). Within the seven sites occupied in the Marquesas Keys, 
the highest counts ranged from 8 to 521 depending upon site and 
sampling date (Cannon et al. 2007, p. 7; 2010, p. 848). The highest 
count on Boca Grande was 441 in February 2007 (Cannon et al. 2007, p. 
7; 2010, p. 848). Highest counts occurred when blackbead flowered 
profusely and produced new leaves (Cannon et al. 2010, p. 851). In 
March and April, blackbead was observed to yield little new growth and 
no flowering, and oviposition by Miami blues was not observed (Cannon 
et al. 2007, p. 8). Partial searches on two islands in May and June 
revealed few Miami blues; little new leaf growth and no flowering of 
blackbead was observed at these locations after February 2007 (Cannon 
et al. 2010, p. 850). Seasonality observed on KWNWR was different than 
that described for the BHSP metapopulation (above). Hurricane Wilma 
(October 2005) heavily damaged or killed blackbead stands at most 
sites, but it also likely enhanced foraging habitat, if only 
temporarily, on select islands within the KWNWR (Cannon et al. 2007, p. 
10; 2010, p. 851) (see Summary of Factors Affecting the Species).
    Periodic surveys at KWNWR in 2008 and 2009 suggested lower levels 
of abundance, based upon limited effort (Emmel and Daniels 2008, pp. 7-
10; 2009, pp. 9-13). In February 2008, researchers recorded 3 adults on 
Boca Grande and a total of 32 adults at two islands within the 
Marquesas; lack of rainfall resulted in very limited adult nectar 
sources and limited new growth of larval host (Emmel and Daniels 2008, 
pp. 7-8). In April 2008, one adult was recorded on Boca Grande; one 
adult was also recorded at another island (Emmel and Daniels 2008, p. 
8). In June 2008, no adults were located on Boca Grande, and a total of 
27 were recorded from two other islands (Emmel and Daniels 2008, p. 9). 
In August 2008, no adults were found at Boca Grande, and five adults 
were recorded at another island (Emmel and Daniels 2008, p. 10). In 
March 2009, no adults were recorded on Boca Grande; habitat conditions 
were deemed very poor, with limited new host growth and available 
nectar resources (Emmel and Daniels 2009, p. 12). In April 2009, 
researchers found a total of 22 adults from two islands within the 
Marquesas (Emmel and Daniels 2009, p. 13).
    Based upon limited data and observations, the Miami blue persisted 
on various islands within the KWNWR in 2010. From April through July 
2010, the Miami blue was observed on 5 of 10 dates at one location 
within the Marquesas, although in limited numbers during brief surveys 
(T. Wilmers, pers. comm. 2010b). On July 28, 2010, researchers recorded 
19 adults from three islands within the Marquesas, in limited surveys; 
another 25 adults were recorded on Boca Grande in less than 1 hour of 
survey work (J. Daniels, pers. comm. 2010a). On September 30, 2010, 
dozens of Miami blues were observed on Boca Grande; this may have 
represented an actual population size in the hundreds (N. Haddad, pers. 
comm. 2010). On November 24, 2010, researchers positively identified 48 
Miami blue adults on Boca Grande in less than 3 hours of surveys, 
noting that assessment was difficult due to the

[[Page 49549]]

many hundreds or possibly thousands of cassius blues, which were also 
present (P. Cannon, pers. comm. 2010b; T. Wilmers, pers. comm. 2010a). 
In March and April 2011, researchers observed Miami blue adults at five 
sites within KWNWR in numbers similar to those reported above (N. 
Haddad, pers. comm. 2011). In July 2011, fewer adults were observed (P. 
Hughes, pers. comm. 2011).
    At this time, it is unclear what the size of the metapopulation at 
KWNWR is or its dynamics. However, available data (given above) suggest 
wide fluctuations of adults within and between years and sites. The 
frequency of dispersal between islands is also not known (Cannon et al. 
2010, p. 852). Due to the distance between the Marquesas and Boca 
Grande (i.e., about 7 miles [11 km]) and the species' limited dispersal 
capabilities, it is possible that two (or more) distinct 
metapopulations exist within KWNWR (J. Daniels, pers. comm. 2010b). In 
September 2010, the Service initiated a new study with researchers from 
NCSU to conduct a comprehensive examination of potential habitat within 
KWNWR and GWHNWR, quantify current distribution and habitat use, and 
develop a monitoring protocol to estimate detectability, abundance, and 
occupancy parameters.

Gene Flow and Genetic Diversity Within Contemporary Populations

    Saarinen (2009, pp. 15, 29-33, 40, 44) and Saarinen et al. (2009b, 
pp. 242-244) examined 12 polymorphic microsatellite loci (noncoding 
regions of chromosomes) to assess molecular diversity and gene flow of 
wild and captive-reared Miami blue butterflies; also, one 
microsatellite locus was successfully amplified from a subset of the 
museum specimens. Although results from historical specimens should be 
interpreted with caution (due both to small sample size and the single 
microsatellite locus), Saarinen (2009, pp. 15, 50-51) reported some 
loss of diversity in the contemporary populations, though less than had 
been expected. Even with small sample sizes, historical populations 
were significantly more diverse (with generally higher effective 
numbers of alleles and observed levels of heterozygosity) than BHSP; 
KWNWR population values were between historical values and BHSP values 
(Saarinen 2009, pp. 44-46).
    Both historical and contemporary populations showed evidence of a 
metapopulation structure with interacting subcolonies (E.V. Saarinen 
and J.C. Daniels, unpub. data as cited in Saarinen 2009, p. 49). 
However, the metapopulations at BHSP and KWNWR are separated by a 
distance of more than 43 miles (70 km). Given the Miami blue's poor 
dispersal capabilities (E.V. Saarinen and J.C. Daniels, unpub. data as 
cited in Saarinen 2009, p. 22), it is highly unlikely that they 
interacted. Saarinen's work showed no gene flow and a clear distinction 
between the BHSP and KWNWR metapopulations (Saarinen 2009, pp. 36, 74, 
89) (see Summary of Factors Affecting the Species).
    Studies addressing molecular diversity at BHSP showed the effective 
number of alleles remained relatively constant over time, at both a 
monthly (generational) and annual scale (Saarinen 2009, pp. 71, 84). 
Allelic (gene) richness was also stable over time in BHSP, with values 
ranging from 2.988 to 3.121 when averaged across the 12 microsatellite 
loci from September 2005 to October 2006. These values were lower than 
those in KWNWR [3.790] (Saarinen 2009, p. 71). However, data showed 
that the BHSP metapopulation retained an adequate amount of genetic 
diversity to maintain the population in 2005 and 2006, despite 
perceived changes in overall population size (Saarinen 2009, p. 77). No 
significant evidence of a recent genetic bottleneck was found in the 
BHSP generations analyzed, however, there may have been a previous 
bottleneck that was undetectable with methods used (Saarinen 2009, pp. 
72, 85, 141).
    To explore the level of gene flow and connectivity between discrete 
habitat patches at BHSP, Saarinen (2009, pp. 64-65) conducted analyses 
at several spatial scales, analyzing BHSP as a single population (with 
no subdivision), as individual colonies occupying discrete habitat 
patches (as several groups acting in a metapopulation structure), and 
as a division of clumped colonies versus other, more spatially distant 
colonies. Analyses of microsatellite frequencies were also used to 
assess gene flow between habitat patches (Saarinen 2009, p. 72). While 
some subpopulations were well linked, others showed more division 
(Saarinen 2009, p. 73). High levels of gene flow (and relatively little 
differentiation) were apparent even between distant habitat patches on 
BHSP, and the smaller patches, such as those along the Main Road, 
appeared to be important links in maintaining connectivity (Saarinen 
2009, pp. 78, 141). Overall, gene flow between habitat patches on BHSP 
was considered crucial to maintain genetic diversity and imperative for 
the Miami blue's long-term persistence at this location (Saarinen 2009, 
p. 141).
    The metapopulation structure on KWNWR is more extensive than that 
which occurred at BHSP (Saarinen 2009, p. 49). Due to small sample 
sizes from Boca Grande, only samples from the Marquesas Keys were used 
for genetic analysis of KWNWR, and results were limited (Saarinen 2009, 
pp. 66, 72). Overall, this metapopulation was found to have higher 
genetic diversity (mean observed heterozygosity of 51 percent versus 
39.5 percent) than the BHSP population (Saarinen 2009, p. 49). Allelic 
richness (3.790 in February 2008) was also higher in KWNWR (Saarinen 
2009, pp. 71, 75). Accordingly, KWNWR is a particularly important 
source of variation to be considered for future conservation efforts 
for this taxon (Saarinen 2009, pp. 71, 75), especially if this is the 
only extant metapopulation(s) remaining. The KWNWR metapopulation 
showed signs of a bottleneck and may support the hypothesis that it is 
a newly founded population (Saarinen 2009, pp. 76, 141). Further work 
is needed to better understand the metapopulation dynamics and genetic 
implications in this population.

Previous Federal Action

    On May 22, 1984, we published a Review of Invertebrate Wildlife for 
Listing as Endangered or Threatened Species (49 FR 21664), which 
included the Miami blue butterfly (Hemiargus thomasi bethune-bakeri) as 
a category 2 candidate species for possible future listing as 
threatened or endangered. Category 2 candidates were those taxa for 
which information contained in our files indicated that listing may be 
appropriate, but for which additional data were needed to support a 
listing proposal. In a January 6, 1989, Animal Notice of Review (54 FR 
572), the Miami blue butterfly continued as a category 2 candidate, 
with a name change from bethune-bakeri to bethunebakeri. On November 
21, 1991, the Miami blue was downgraded from a category 2 to category 
3C species in an Animal Candidate Review for Listing as Endangered or 
Threatened Species (56 FR 58830), characterized as having an unknown 
trend (meaning additional survey work was required to determine the 
current trend). Category 3C species were those taxa that had proved to 
be more abundant or widespread than previously believed and/or those 
that were not subject to any identifiable threat. In 1996, Category 3 
species were removed from the candidate list (61 FR 7596).
    On June 15, 2000, we received a petition from the NABA and Mark 
Salvato to emergency list the Miami

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blue butterfly (Hemiargus thomasi bethunebakeri) as endangered with 
critical habitat pursuant to the Act. The petition cited habitat loss 
and fragmentation, influence of mosquito control chemicals, unethical 
butterfly collection, and human-caused changes to habitat occupied by 
the subspecies' only known population.
    On August 29, 2001, the Department of the Interior reached an 
agreement with several conservation organizations regarding a number of 
listing actions that had been delayed by court-ordered critical habitat 
designations and listing actions for other species. That agreement was 
subsequently approved by the U.S. District Court for the District of 
Columbia. Under the agreement, we and the conservation organizations 
agreed to significantly extend the actions on the other species, 
thereby making funds available for a number of listing actions judged 
to be higher priority. Those higher priority listing actions included 
the 90-day finding for the petition to list the Miami blue butterfly.
    On January 3, 2002 (67 FR 280), we announced our 90-day finding for 
the petition to list the Miami blue, initiated a status review, and 
sought data and information from the public. In this finding, we 
indicated the Miami blue may be in danger of extirpation. However, we 
did not believe the threats to be so great that extirpation was 
imminent, requiring us to provide emergency protection to the butterfly 
through our emergency listing provisions. We indicated that we could 
issue an emergency rule when an immediate threat posed a significant 
risk to the well-being of the subspecies.
    On May 11, 2005, we recognized the Miami blue butterfly as a 
Federal candidate subspecies in our annual Candidate Notice of Review 
(70 FR 24872). This action constituted a 12-month finding for the 
subspecies in which it was determined that the subspecies was warranted 
but precluded for listing by other higher priority listing actions. On 
November 9, 2009, in our annual Candidate Notice of Review (74 FR 
57809), we changed the Listing Priority Number (LPN) for the Miami blue 
from 6 to 3 due to increased and more immediate threats.
    On August 10, 2010, the Service received a renewed petition from 
the NABA for emergency listing of the Miami blue butterfly as 
endangered. This petition stated that the entire remaining population 
is in significant and immediate danger because it exists in a single 
location and is subject to hurricanes, iguanas, and human impacts given 
that the area is remote and difficult to patrol. On January 11, 2011, 
the Service received a separate petition for emergency listing of the 
Miami blue butterfly with critical habitat from the Center for 
Biological Diversity.
    The Miami blue butterfly is currently a Federal candidate (LPN of 
3) and State-threatened subspecies.
    The Service's decision to emergency list the Miami blue butterfly 
resulted from our careful review of the status of the subspecies and 
the threats it faces. We based this decision on information in our 
files or otherwise available to us (including the results of recent 
status surveys) as well as information contained in the original 
petition (2000), the renewed petition (2010), the new petition (2011), 
and information referenced in the petitions.
    The proposed rule to list the Miami blue butterfly as endangered is 
published concurrently with this emergency rule and found in this issue 
of the Federal Register in Proposed Rules.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533), and its implementing 
regulations at 50 CFR part 424, set forth the procedures for adding 
species to the Federal Lists of Endangered and Threatened Wildlife and 
Plants. Under section 4(a)(1) of the Act, we may determine a species to 
be endangered or threatened due to one or more of the following five 
factors: (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range; (B) overutilization for 
commer