An insect anti-antiaphrodisiac

Authors: Brent, Colin; BYERS, JOHN - Hebrew University; LEVI-ZADA, A. - Agricultural Research Organization Of Israel

Submitted to: eLife
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2017
Publication Date: 7/11/2017
Publication URL: https://handle.nal.usda.gov/10113/5763046
Citation: Brent, C.S., Byers, J.A., Levi-Zada, A. 2017. An insect anti-antiaphrodisiac. eLife. doi:10.7554/eLife.24063.

Interpretive Summary: Passive mechanisms of mate guarding are used by males to promote sperm precedence. Some male insects transfer antiaphrodisiacs that repel competitors from recently mated females. However, such simple signaling can be inaccurate, negatively impacting fitness in the females and their prospective mates. We tested odorants emitted from mated females of an insect species known to transmit an antiaphrodisiac in seminal fluids. In addition to finding two male-derived compounds that repel other males, we found one of these was chemically converted in the female before externalization. This third compound counteracted the antiaphrodisiac effect but had no attractant or excitatory properties itself. This is the first evidence for such an anti-antiaphrodisiac pheromone in any organism, adding a new element to the communication mechanisms regulating reproductive behaviors.

Technical Abstract: Passive mechanisms of mate guarding are used by males to promote sperm precedence with little cost, but these tactics can be disadvantageous for their mates and other males. For species in which females mate multiple times, the duration of the mate guarding may exceed the period during which the female has sufficient viable sperm available to fertilize the eggs she produces and deny other males insemination opportunities. The seminal fluids of the plant bug Lygus hesperus have known antiaphrodisiac properties that render mated females unattractive for several days. Investigation of the compounds involved revealed that males implant myristyl acetate and geranylgeranyl acetate during mating which reduce female attractiveness. Myristyl acetate presented alone effects male behavior while the second compound was active only when paired with the former. These compounds are gradually released from the female’s gonopore, declining until they drop below an activation threshold concentration needed to suppress male courtship. Because the starting quantities of these compounds can vary depending on the condition of the inseminating male, the repellant signal becomes less reliable over time. Evidence was found of a complimentary mechanism that more accurately conveys the female’s mating status. Once inside the female, geranylgeranyl acetate is progressively converted to geranylgeraniol that is also slowly released. The geranylgeraniol counteracts the antiaphrodisiac effect in a dose dependent manner despite having no inherent attractant properties of its own. This is the first evidence for such an anti-antiaphrodisiac in any organism, adding a new element to the communication mechanisms regulating reproductive behaviors.