Web wars: males of the golden orb-web spider Trichonephila clavipes escalate more in contests for mated females and when access to females is easier

• Autor(a) principal: Amanda Vieira da Silva
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/33326
• topic: agonistic interactions; male-male contests; resource value; female traits; mate searching; intrasexual selection; Ecologia; Aranhas; Comportamento sexual animal

During contests for access to females, males may pay several costs that change according to the time invested in the interaction or the behaviors adopted during contest. For this reason, it may be that males increase their investment in contests when the expected benefits obtained with victory are higher. The benefits could vary according to female traits or to the cost that males have pay to find females. In this study, we tested the hypotheses that males of the golden orb-web spider, Triconephila clavipes, invest more in contests for access to virgin and more fecund females and when access to females is harder. To test these hypotheses, we recorded the occurrence, duration and adoption of more aggressive behaviors (i.e., escalation) during the contests between males for access to mated and virgin females. In each contest, we also estimated female fecundity and recorded if the female web occurred isolated or in aggregation with other female webs (information used as a proxy for the cost that loser males would have to pay to find new females). We found that the occurrence and duration of contests were unrelated to female traits. However, the probability of escalation during the contests was higher in two situations: 1) when females were adults (and probably mated) and 2) when females were aggregated. These results indicate that males of T. clavipes adjust investment in contests, but contrarily to our predictions. We suggest that the investment in contests is higher for adult than juvenile females because males are defending mated females to avoid sperm competition, and in female aggregations due to the high turnover of rival males, which prevents an establishment of dominance hierarchy.