( CNN ) -- At his version of an ICU unit , Jaret Daniels pays extraordinary attention to his young charges . Each of the creatures is kept in its own plastic cup , isolated to prevent the spread of disease . Not just any food will do . In their climate-controlled environment , the Schaus swallowtail caterpillars munch voraciously on wild lime . Daniels , an entomologist at the University of Florida , is raising seven immature butterflies belonging to a species that is critically endangered and just `` hanging on . '' The pressure , Daniels said , is enough to keep him up at night . He and others are trying to save an insect that is on the brink of extinction and in need of human intervention . The U.S . Fish and Wildlife Service issued an emergency directive in 2012 to collect females in Biscayne National Park and raise their eggs . While no females were collected last year , officials announced this week that an adult female was snared on the park 's Elliott Key last month , along with six larvae . The female produced one egg . Federal and state officials say the Schaus ' hopes might depend on a breeding program that may help safeguard a portion of the remaining population . `` I know what I am doing , '' Daniels told CNN on Tuesday . `` I am going to do the best that I can do . '' The Schaus swallowtail , contained to a relatively small area in southeastern Florida , in 1976 was listed under the Endangered Species Act as threatened . It reached the endangered status eight years later . The colorful butterfly 's numbers have dropped precipitously over the decades . Captive breeding was tried in the 1980s and 1990s , boosting the Schaus numbers for a time . That did n't last long . During a 2011 survey , there were only 41 sightings , mostly on Elliott Key . That number dropped to four last year . Habitat destruction , drought , hurricanes and pesticide use outside Biscayne National Park were likely contributing factors to the insect 's demise , experts say . But a glimmer of hope broke out this spring in the park south of Miami when seven adult butterflies were spotted . Marissa Streifel , a research technician , collected the adult female on May 21 . Daniels had a hard time hearing her during a static-laden phone call . `` I recall her saying , 'We got one . Woo-hoo ! ' `` Daniels said . Streifel used a net to capture the female , a challenge in the dense hammock vegetation . `` If you know how to use it well , the chance of injuring the butterfly is extremely low , '' Daniels said . After four days in an enclosure , the female was released . Because of heavy rain and poor weather conditions , she produced only one viable egg , the size of the head of a pin . It is one of the larvae in the University of Florida laboratory in Gainesville . But in a razor-thin scenario , that 's certainly better than none . Schaus swallowtails generally live only two weeks in the wild , perhaps 30 to 40 days in captivity . They reproduce only once a year . After a 10- to 11-month pupa stage , butterflies will emerge bearing black-brown wings with yellow markings and a broad rusty patch beneath the hind wing . They feature aquamarine spots . Experts hope all seven in the lab will survive to adulthood . Elsa Alvear , chief of resource management at Biscayne National Park , told CNN they `` may make a difference between extinction and nonextinction . '' `` This species used to be found in a lot of places in South Florida and the Keys , '' she said . `` We want to get numbers up and see it restored to more than just one island . '' The search for more females is continuing this summer . Researchers hope they can net a female that will produce a couple hundred eggs , providing a huge boost to the desperate situation . `` If she is productive , you can ramp up that population pretty quickly , '' said Daniels . Of the seven butterflies , one is in the pupa phase and another is close to it . Once they complete that lengthy stage , they emerge , show their spectacular colors and take flight . That 's expected to take place next spring , unless officials decide to simulate spring rains to bring them out early . Daniels said he is cautiously optimistic about the latest developments , although the Schaus swallowtail faces daunting challenges . There is no flexibility if weather or other factors turn against the insect . `` Even a minor disturbance can deal a death blow to this organism , '' Daniels said . Alvear said volunteers at the national park are helping to plant wild lime and torchwood , both food sources for the Schaus swallowtail . `` It is a beautiful butterfly , and it would be a shame to lose this , '' she said .
Researchers are caring for caterpillars of endangered species . The Florida swallowtail butterfly has declined in numbers . It occurs only in a small area within South Florida , mostly on small islands . University of Florida entomologist is caring for caterpillars .