The Evolution of Sexual Communication in Fireflies."
Dr. Marc A. Branham, Assistant Professor
University of Florida, Department of Entomology, Gainesville, FL. USA.
Fireflies show a diverse array of sexual signals, including photic signals in conjunction with pheromones, or either photic signals or pheromones alone. This is the first study of the origin of photic signals in these beetles. Morphological characters were studied in 81 species, including 48 families and their near relatives. This analysis indicates that the origin of bioluminescence in these beetles precedes the evolution of the family Lampyridae, evolving first in the larvae of an ancient ancestor and then carrying over into adults in fireflies. Taxa formerly thought to be closely related to fireflies because of their luminous adults are shown to be only distant relatives (e.g. Phengodidiae). Pheromonal sexual signal systems compose the basal region of the family Lampyridae and are lost in some of the clades that employ photic sexual signals. This phylogeny also hypothesizes multiple origins of flashing behavior in fireflies. This study illustrates the importance of phylogenetic methods for tracing the evolutionary origin, function and maintenance of sexual signal systems in organisms employing bioluminescent or other signal modalities (chemical, acoustic or non-photic visual signals.)