Sexual differences in weaponry and defensive behavior in a neotropical harvestman  

作　　者：Julio M.G.SEGOVIA Gabriel P.MURAYAMA Rodrigo H.WILLEMART 

机构地区：[1]Laboratorio de Ecologia Sensorial e Comportamento de Artropodes,Escola,de Artes,Ciencias e Humanidades da Universidade de Sao Paulo,Sao Paulo,Brazil [2]Programa de Pos-Graduaqao em Zoologia,Instituto de Biociencias,Universidade de Sao Paulo,Sao Paulo,Brazil [3]Programa de Pos-Graduaqao em Ecologia e Evoluqao,Universidade Federal de Sao Paulo,Sao Paulo,Brazil

出　　处：《Current Zoology》2019年第5期553-558,共6页动物学报（英文版）

摘　　要：Sexual differences in morphology can evolve by sexual selection and/or natural selection.In some species,only males have morphological structures that are used as weapons.Since some weapons may also be used for defensive purposes,males and females may behave differently towards predators.In some species of harvestmen(Arachnida and Opiliones),males have sharp apophyses("spines")on their 4th pair of legs whereas females lack them.Those apophyses are used in malemale fights and in antipredatory behaviors.The harvestmen antipredatory repertory also encompasses passive defenses such as thanatosis(death feigning),retaliation(attack on predators),and chemical defense.Due to the sexual differences on weaponry,we hypothesized that males and females of Mischonyx cuspidatus(Gonyleptidae)rely on different defensive strategies.We experimentally induced males and females to perform 3 defensive behaviors:thanatosis,pinching with legs,and chemical release.We predicted that females would engage more in passive and chemical defenses than males,whereas males would rely more on retaliation than females.As expected,females performed thanatosis more often than males.Likewise,males performed retaliation more often than females.We did not find differences in the rate of chemical defense use between the sexes.This study provides evidence that due to sexual dimorphism,alternative antipredatory behaviors may have been selected in the different sexes in M.cuspidatus.

关 键 词：ARACHNIDA DEATH FEIGNING nipping thanatosis WEAPON OPILIONES 

分 类 号：O18[理学—数学]