Meeting Abstract

P1-78   -   Monandrous females regain sexual receptivity after short copulations Cirino, LA*; Rodríguez, RL; University of Wisconsin-Milwaukee; University of Wisconsin-Milwaukee cirino@uwm.edu https://lacirino.weebly.com/

Male fitness is a function of the number of mates they can inseminate, yet males often engage in prolonged copulations. Potential explanations for this behavior include the ejaculate transfer hypothesis, whereby longer copulations achieve higher levels of insemination, and the mate guarding hypothesis, in which males increase their association with females for longer than required for sufficient sperm transfer. Interestingly, prolonged copulations can occur in monandrous species where these benefits presumably do not apply. We investigated prolonged mating in a monandrous-polygynous species, a member of the Enchenopa binotata complex of treehoppers (Hemiptera: Membracidae). These insects communicate with plant-borne vibrational signals and use male-female duets in pair formation. Copulation can last up to three hours. We tested a version of the mate guarding hypothesis by which prolonged copulation has the function of allowing males to transfer ejaculate which reduces female receptivity. If so, females would be more likely to duet with male signals as mating duration declined. We randomly assigned receptive females to copulation duration treatments of either 5, 10, 30, or 60 minutes before we separated the pairs or a control of uninterrupted copulations. We found that females that experienced copulations lasting less than or equal to 30 minutes were more likely to duet with playbacks the following day compared to those that mated for 1 hour. Control females (copulations lasting 128 minutes, on average) never subsequently duetted with playbacks. Our results support the mate guarding hypothesis and suggest that extreme copulation length may function to allow for the transfer of ejaculate substances that lower female receptivity or even effectively cause monandry.