Evolutionary Reproductive Strategies of Males Short-Tailed Fruit Bat (Carollia perspicillata: Phyllostomidae)
|Director of thesis||Prof. Heinz Richner|
|Co-director of thesis|
|Summary of thesis||
Reproduction is a major objective for every living thing. Consequently, the behavioral and physiological reproductive strategies are under strong natural selection. With more than 1000 species worldwide and unique adaptive mechanisms within the mammalian class, bats represent an interesting research niche. Carollia perspicillata (Phyllostomidae) was described as resource-defense polygynous species; males try to keep a restricted access to the female preferred areas. Two types of male reproductive strategies were highlighted. Heavier and older males occupy the best roosting sites and profit of female access; whereas "bachelor" satellite males attempt to gain copulation by intruding the "harems”. For the latter sperm competition is expected to be higher than for dominant males. Indeed, a sneaked copulation will automatically induce sperm competition, while within-harem mating is not always followed by extra-pair copulation. I first expect physiological adaptations on sperm production (morphology, quantity and quality) and on the histological testicular organization related to social status. Although the cost of dominance paradigm remains to be tested for this species, restricted access toward females may provoke an increase in stressors such as challenges of satellite males or reduce resting time and foraging possibilities. Dominant males have to respond to these stressors. Therefore, I would then like to investigate the dominant male trade-offs occurring between maintenance of testosterone, control of stress hormones and protection of the germline against oxidative damages. Because age and senescence may restrict physiological adaptation leeway for dominant males, I also would like to test whether social vocalizations can honestly signal capabilities of the male to cope with environmental stressors and reduce satellite challenges.
|Administrative delay for the defence|