Submitted to: Florida Entomologist
Publication Type: Review Article
Publication Acceptance Date: 5/14/1998
Publication Date: N/A
Interpretive Summary: Traps designed to monitor or control pests can be improved through greater understanding of insect behavior. Predaceous insects, and organisms that eat insects, sometimes exploit the behaviors of their prey. For example, certain spiders mimic the sex pheromones of female moths, and then feed on the male moths they attract. An understanding of "aggressive signals" can suggest means of attracting and controlling insect pests. A few carnivorous flies produce spider-like webs, and emit light from various forms of light organs. This luminescence attracts other insects, including other flies, into the web where they are overcome and eaten. The behaviors of luminous flies have been reviewed and interpreted by an ARS scientist at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Fl. Among the patterns uncovered is a tendency to produce light with a much shorter wave length (blue) than the "non aggressive" lights (green and yellow) typical of insects such a s fireflies. The reasons why this color of light might be particularly attractive to nocturnal insects are discussed. Traps incorporating blue lights might be particularly attractive to certain nocturnal pests.
Technical Abstract: Many arthropods move toward or a way from lights. Larvae of certain luminescent mycetophilid fungus gnats exploit this reaction to obtain prey. They produce mucus webs, sometimes festooned with poisonous droplets, to snare other species of flies and a variety of small arthropods. Their lights may also protect luminous Mycetophilidae from their own negatively phototropic predators and be used as intraspecific signals of size and vigor in aggressive interactions with other larvae. Luminescence in female pupae and adults attracts potential mates. Lights may aid hymenopterous parasitoids of the fungus gnats to locate hosts, and parasitoid flies, phorids and tachinids, may use lights to forage for luminous hosts , such as lampyrid fireflies. The luminescence of mushrooms can attract small Diptera, and may have evolved to aid mechanical spore dispersal. Among Diptera bioluminescence is found only in the Mycetophilidae, but the variety of light organs in fungus gnats suggests multiple evolutions of the trait. This concentration of bioluminescence may be due to the unusual, sedentary nature of prey capture (i.e., use of webs) that allows the "mimicry" of a stationary abiotic light cue, or the atypically potentent defenses webs and associated chemicals might provide (i.e., an aposematic display of unpalatability).