The term “chemical genitalia” in insect biology

The term “chemical genitalia” refers to natural chemical compounds (accessory proteins accompanying semen) that influence sperm persistence and egg fertilization in multiple mating events. Marlene Zuk describes how male insects use this strategy to kill the sperm of previous mates or to render females less receptive to future matings [1].  Those chemicals have been best studied in the fruit fly Drosophila. She also informs us that the phrase “chemical genitalia” was originally used by William G. Eberhard of the Smithsonian Tropical Research Institute and his colleague Carlos Cordero from the National Autonomous University of Mexico to name the seminal products. Eberhard works in Panama and Costa Rica on a wide variety of spiders and insects.

The activity of chemical genitalia can be considered as a special form of sperm competition—or, more precise, as a post- or inter-coital “cryptic chemical attack,” eliminating or reducing the female choice over paternity.

Keywords: entomology, behavioral ecology, biochemistry, selective reproduction, sexual selection, evolution, competition among males, chemical activity

Reference
[1] Marlene Zuk: Sperm and Eggs on Six Legs. Natural History June 2011, 119 (6), 28-35.