The Occurrence and Behaviors of North American Fireflies (Coleoptera: Lampyridae) on Milkweed, Asclepias syriaca L.

Abstract

At four sites spanning a general triangle with 50–100 km legs in East Tennessee over a six-week period in July and August 2013, 56 fireflies, male and female, from four species and three genera were associated with common milkweed, Asclepias syriaca L. Photinus pyralis (L.), Photinus cooki Green, Pyropyga minuta LeConte, and an determined species of Photuris Dejean repeatedly exhibited seven common behaviors of nectaring from individual blooms and stigmatic slits and actively mouthing floral stems, recurved sepals, and uppermost leaves, lasting from 9–175 minutes. Milkweed pollinia were noted on three of the four species. Maximum firefly presence was observed the first two survey days, 7 and 8 July, falling to low but persistent numbers the remainder of the survey. These firefly behaviors were observed primarily in the four hours before sunset and after sunrise. Twelve Photuris larvae were observed feeding on milkweed rhizomes in captivity. Reports of milkweed-firefly associations involving at least four additional firefly species in two additional genera, Lucidota atra (Olivier), Photinus indictus (LeConte), Pyropyga decipiens (Harris) and a species of Pyractomena Melsheimer spanning 90 years across the eastern US are presented along with recent reports of similar behaviors witnessed from Texas to Canada.