Firefly+Bioluminescence


 * Firefly Bioluminescence **



Kingdom: Animalia
 * Figure 1**: Composite of long exposures showing firefly (//Photinus pyralis//) bioluminescence. Photo by Alex Wild (www.alexanderwild.com).

Phylum: Arthropoda Class: Insecta Order: Coleoptera Family: Lampyridae

The bioluminescence of fireflies is produced by a two-step reaction which is catalyzed by an enzyme called luciferase. Not all adult forms of fireflies produce light, some basal lampyrids lose photic organs after the larval stage. These photic organs are referred to as lanterns. Lanterns can be used for different strategies such as predator avoidance and mate attraction.
 * Bioluminescence in Lampyridae (fireflies)**
 * Figure 2 ** : Larval stage of a firefly. Photo by Alex Wild (www.alexanderwild.com).

Photic signals from light producing Lampyridae can serve several functions. Most luminescent larvae from the basal sister taxa of cantharoids possess photic organs that are most easily seen from the sides or from above which suggests an aposematic warning display function. Phylogenetics show that luminescence arose in larval forms of cantharoids as aposematic displays and then was also used as a sexual signal in adults of some cantharoid families. Lampyridae then took these functions and expanded on them.
 * Origins of photic signaling**


 * Uses of photic signaling in Lampyrids**
 * Figure 3:** Female firefly predating on a male of another firefly species. Photo by J.E. Lloyd – University of Florida.

The basal use of photic signals was used as an aposematic display in sister taxa to lampyrids, so it’s no surprise that lampyrid larvae still utilize this function. Firefly larvae produce defensive steroids called lucibufagins which are used as a chemical defense against predators. The larval photic organs can be retained or lost in adult forms, depending on the genus.
 * Aposematic**


 * Figure 4 ** : Illuminated male firefly ( // Photinus pyralis // ). Photo by Alex Wild (www.alexanderwild.com).

Adult firefly photic organs are generally more complex and visual when they are used for courtship behaviors. Both females and males produce light, although the systems in which the light is used can vary from taxa to taxa. For firefly organisms that use solely luminescence in mating behavior flashing signals are usually employed rather than glows. For these fireflies the primary signalers are males and the females respond by flashing commencing a dialogue between the male and female.
 * Courtship**

Branham, M. A., AND J. W. Wenzel. 2001. The evolution of bioluminescence in cantharoids (Coleoptera : Elateroidea). Florida Entomologist 84:565- 586. Branham, M. A., AND J. W. Wenzel. 2003. The origin of photic behavior and the evolution of sexual communication in fireflies (Coleoptera : Lampyridae). Cladistics-the International Journal of the Willi Hennig Society 19:1-22. Eisner, T., D. F. Wiemer, L. W. Haynes, AND J. Meinwald. 1978. DEFENSE-MECHANISMS OF ARTHROPODS .59. LUCIBUFAGINS - DEFENSIVE STEROIDS FROM FIREFLIES PHOTINUS-IGNITUS AND PHOTINUS-MARGINELLUS (COLEOPTERA LAMPYRIDAE). Proceedings of the National Academy of Sciences of the United States of America 75:905-908. Lewis, S. M., AND C. K. Cratsley. 2008. Flash signal evolution, mate choice, and predation in fireflies. Pp. 293-321 in Annual Review of Entomology. Annual Reviews, Palo Alto.
 * Literature Cited:**