Offenders tend to be heavier: experimental encounters in mangrove-dwelling monitor lizards (Varanus indicus)

详细信息    查看全文

• 作者：Petra Frýdlová ; Olga Šimková ; Veronika Janovská ; Petr Velenský…
• 关键词：Aggression ; Assessment ; Offender ; Ritualized combat ; Sequential assessment game theory ; Varanidae
• 刊名：acta ethologica
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：20
• 期：1
• 页码：37-45
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Behavioral Sciences; Zoology; Evolutionary Biology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1437-9546
• 卷排序：20

文摘

The evolution of male-biased sexual size dimorphism is often explained by sexual selection providing competitive advantage to the larger males. The aggressive interactions are often dangerous and energy consuming; thus, it is advantageous to reduce the risks by adjusting behavior to correspond with body size as a predictor of fighting success. Organization of contests into distinct phases with the initial displays preceding the real combat allows individuals to assess the body size and strength of the rival. We staged interactions between mangrove-dwelling monitor lizards (Varanus indicus) to uncover the initialization of aggression and factors determining the course of an encounter. The analyses revealed the importance of both absolute and relative body size of encountering males. The attack rate increases with the body weight of the lizard and offenders initializing a contact phase of the fight tend to be the heavier male of the dyad. Regardless of the final outcome of the combat, the results show that only short visual contact provides sufficient information about the body size of the opponent. This enables combatants to determine whether to initiate the fight or not. This finding together with the ethological details of contests provides the first evidence for the ability of mutual assessment in varanids.