How pre- and postcopulatory sexual selection influence male mating decisions in a promiscuous species

This work was supported by Portuguese National Funds through FCT (Fundação para a Ciência e a Tecnologia), within the cE3c Unit FCT funding (grant number UID/BIA/00329/2013), IO PhD grant (grant number SFRH/BD/90686/2012) and SAMV and MB Post-Doctoral research grants (grant numbers SFRH/BPD/66042/2009 and SFRH/BPD/82259/2011, respectively). This work was also supported by ERC (European Research Council) BioTIME (grant number 250189).When females mate multiply, male reproductive success depends on both pre- and postcopulatory processes, including female choice and sperm competition. However, these processes can favour different mating tactics in males. Here we used the Trinidadian guppy, Poecilia reticulata, system to understand how this conflict is resolved. We asked whether knowledge of recent female mating history leads males to adjust their mating effort with respect to the time devoted to mating activity, and the frequency and the sequence of mating tactics employed. To do this we quantified male mating behaviour in three competitive scenarios: (1) Single, when a focal male arrives near a single female and remains alone with her; (2) First, when a focal male is joined by a rival male; and (3) Second, when a focal male arrives after a rival male. We hypothesized that males adjust their behaviour based on arrival order. If female sequential mate choice is the main process shaping male mating behaviours (favouring First males in guppies), males should avoid competition and invest most when Single. Alternatively, if last- male sperm precedence is the major driver of decision making, males should invest more in mating attempts in the Second scenario. Greatest investment when First implies an intermediate strategy. We found that order of arrival influenced mating decisions with most mating activity during the First rather than the Single and Second scenarios. This result suggests that both pre- and postcopulatory processes influence mating investment, and that individual males make contingent decisions to maximize both mating and fertilization success.PostprintPeer reviewe