The Miami blue butterfly (Cyclargus thomasi bethunebakeri), once common throughout coastal south Florida, experienced dramatic population declines in the 1980s and 90s and was listed as federally endangered in 2012. Currently, the Miami blue is restricted to several remote islands in the Lower Florida Keys. The Florida Museum of Natural History currently has a captive colony of this butterfly and is working to answer questions about its ecology in order to better inform reintroduction efforts for this organism. We are examining host plant preference, this taxon’s relationships with various species of ants, and other factors using captive individuals in a laboratory as well as a series of field-based experiments in areas of this subspecies’ former range.
Work is ongoing and results are only preliminary, but it appears that Miami blue larvae develop more quickly when reared on grey nickerbean (Caesalpinia bonduc) compared to Florida Keys blackbead (Pithecellobium keyense) and the resulting adults are significantly larger in size, which could have fitness and dispersal implications. This apparent host plant preference has interesting applications for population restoration since the current range for the Miami blue butterfly contains almost exclusively P. keyense with very little C. bonduc present at those sites. We hope to further examine both plant species’ roles in the survival of this subspecies.
It appears that many species of ants will tend to C. thomasi bethunebakeri larvae, but in the wild, this mutualistic relationship is dominated by the Florida carpenter ant (Camponotus floridanus). Additionally, none of the ant species in either the laboratory or the field enclosures have been observed predating Miami blue larvae. The importance of these mutualistic relationships to the conservation of this butterfly is an area that we will further explore in our ongoing research.