Male-male clasping may be part of an alternative reproductive tactic in Xenopus laevis.
Male Xenopus laevis frogs have been observed to clasp other males in a sustained, amplectant position, the purpose of which is unknown. We examined three possible hypotheses for this counter-intuitive behavior: 1) clasping males fail to discriminate the sex of the frogs they clasp; 2) male-male clasping is an aggressive or dominant behavior; or 3) that males clasp other males to gain proximity to breeding events and possibly engage in sperm competition. Our data, gathered through a series of behavioral experiments in the laboratory, refute the first two hypotheses. We found that males did not clasp indiscriminately, but showed a sex preference, with most males preferentially clasping a female, but a proportion preferentially clasping another male. Males that clasped another male when there was no female present were less likely to "win" reproductive access in a male-male-female triad, indicating that they did not establish dominance through clasping. However, those males did gain proximity to oviposition by continued male-male clasping in the presence of the female. Thus, our findings are consistent with, but cannot confirm, the third hypothesis of male-male clasping as an alternative reproductive tactic.
Department of Biology, Denison University, Granville, Ohio, United States of America.
Heather J
HJ
Rhodes
Department of Biology, Denison University, Granville, Ohio, United States of America; Department of Neuroscience, Brown University, Providence, Rhode Island, United States of America.
Rachel J
RJ
Stevenson
Department of Biology, Denison University, Granville, Ohio, United States of America.
Courtney L
CL
Ego
D000374:Aggression; D000818:Animals; D001522:Behavior, Animal; D001947:Breeding; D005260:Female; D008297:Male; D052586:Mating Preference, Animal; D012098:Reproduction; D013094:Spermatozoa / Q000502:physiology; D014982:Xenopus laevis / Q000502:physiology*