Flashing Fireflies

Contrary to the belief of many children, fireflies do not put on light shows for our eyes alone. Male Photinus fireflies conspicuously flash courtship signals while flying to attract females during the mating season. The downside of flashing is not only children catching them in jars, but another larger firefly (Photuris) uses those signals to prey on Photunis. Paul R. Moosman Jr., found that flashing in Photinus fireflies not only attracts mates, but also keeps bats from preying on them.

Photinus fireflies have toxic compounds called lucibufagins. Their flashing acts as an aposematic signal to bats, meaning that it warns them not to ingest the fireflies because they are toxic. To determine this Moosman and his colleagues first captured bats at sites were Photinus fireflies were actively flashing to ensure that the fireflies and bats did coexist. They then analyzed fecal pellets from the bats and found that fireflies were not a part of their diet. There were other insects that were the same size as the fireflies, which ruled out bats not eating them due to size. The bats were given mealworms and mealworms treated with fireflies. Almost all of the bats rejected the mealworms treated with fireflies and they did this after tasting them. When the bats tasted mealworms treated with fireflies they coughed, shook their head, and wiped their snout. The last experiment involved a flashing lure to see how the bats responded. E. fuscus responded to the nonflashing lures while M. lucifugus preferred flashing lures. M. septentrionalis was unaffected by the flashing.

Based on the flashing lures experiment only one of the bat species are able to identify their prey through flash signals before making contact and it just so happens that they also have much better visual acuity than the other bat species. It is interesting though that only E. fuscus could use the flashing cues yet none of the species had Photinus in their diets or found them palatable.

-Tara Quist (6)