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The effects of social experience and orange colouration on mating effort in male guppies (Poecilia reticulata) Goberdhan, Versara Suzan

Abstract

Selection for increased fitness often results in changes to an organism’s behavioural repertoire, and sexual behaviour can be modified in a plethora of ways. Here, I used the Trinidadian guppy, Poecilia reticulata, as a model study species to investigate two different aspects of male sexual behaviour. First, I examined how social environment affects male mate choice. I evaluated whether male guppies with previous social experience of female receptivity cues learn to prefer and adjust their behavioural repertoire towards females with higher receptiveness levels, as this represents an optimal use of time and energy and is more likely to result in insemination. While males that previously experienced receptivity cues did not change the strength of preference towards receptive females (results from dichotomous choice test), these males adapted their mating tactic compared to naïve males (results from no choice tests). This change in mating tactics but lack of preference towards receptive females suggests that although learning from previous experience is important, it might be weaker than predicted in this species. Next, I tested the association between two crucial factors driving sexual selection in this species, male colouration and male mating behaviour. To experimentally test the causal link between these two factors, I used guppies artificially selected for a high or low proportion of orange and quantified their mating tactics. I found that male guppies with greater orange colour increased their mating effort in sexual behaviours directed to court females for insemination. Additionally, males with greater orange colour increased their mating effort in coercive mating tactics. My results suggest that this sexually-selected signal is directly correlated with overall sexual effort. These results support the idea that orange is associated with greater male vigour through higher overall levels of sexual behaviour.

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Attribution-NonCommercial-NoDerivatives 4.0 International