Size-dependent alternative male mating tactics in the yellow dung fly,Scathophaga stercoraria |
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Authors: | Scott Pitnick Kali R H Henn Stephen D Maheux Dawn M Higginson Jorge L Hurtado-Gonzales Mollie K Manier Kirstin S Berben Chase Guptill J Albert C Uy |
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Institution: | 1.Department of Biology, Syracuse University, Syracuse, NY 13244-1270, USA;2.Toad Hollow Farm, 4505 Tanner Road, Nedrow, NY 13120, USA |
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Abstract: | Whenever males can monopolize females and/or resources used by females, the opportunity for sexual selection will be great. The greater the variation among males in reproductive success, the greater the intensity of selection on less competitive males to gain matings through alternative tactics. In the yellow dung fly, Scathophaga stercoraria, males aggressively compete for access to receptive, gravid females on fresh dung. Larger males are better able to acquire mates and to complete copulation successfully and guard the female throughout oviposition. Here we demonstrate that when an alternative resource is present where females aggregate (i.e. apple pomace, where both sexes come to feed), smaller males will redirect their searching for females from dung to the new substrate. In addition, we identify a class of particularly small males on the alternative substrate that appears never to be present searching for females on or around dung. Smaller males were found to have a mating ‘advantage’ on pomace, in striking contrast to the pattern observed on dung, providing further support for the existence of an alternative male reproductive tactic in this species. |
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Keywords: | sexual selection sperm competition body size reproductive strategy Scathophaga stercoraria |
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