Conspicuous cruciform silk decorations deflect avian predator attacks  

作　　者：Bingjun WANG Long YU Nina MA Zengtao ZHANG Deyong GONG Rui LIU Daiqin LI Shichang ZHANG 

机构地区：[1]Centre for Behavioural Ecology and Evolution&State Key Laboratory of Biocatalysis and Enzyme Engineering,School of Life Sciences,Hubei University,Wuhan,Hubei,China [2]Department of Biological Sciences,National University of Singapore,Singapore

出　　处：《Integrative Zoology》2022年第5期689-703,共15页整合动物学（英文版）

基　　金：supported by grants from National Natural Science Foundation of China(31801979 and 31872229);from Singapore Ministry of Education(MOE)AcRF Tier 1 grant(R-154-000-B18-114).

摘　　要：Although camouflage as an effective antipredator defense strategy is widespread across animals,highly conspicuous color patterning is not uncommon either.Many orb-web spiders adorn their webs with extra bright white silk.These conspicuous decorations are hypothesized to deter predators by warning the presence of sticky webs,camouflaging spiders,acting as a decoy,or intimidating predators by their apparent size.The decorations may also deflect predator attacks from spiders.However,empirical evidence for this deflection function remains limited.Here,we tested this hypothesis using the X-shaped silk cruciform decorations built by females of Argiope minuta.We employed visual modeling to quantify the conspicuousness of spiders and decorations from a perspective of avian predators.Then,we determined actual predation risk on spiders using naïve chicks as predators.Spider bodies and decorations were conspicuous against natural backgrounds to the avian visual systems.Chicks attacked the spider main bodies significantly less frequently on the decorated webs than on the undecorated webs,thus reducing predation risk.When both spiders and decorations were present,chicks also attacked the spider main bodies and their legs or decorations,and not randomly:they attacked the legs or decorations sooner and more frequently than they attacked the main bodies,independent of the ratio of the surface area between the decoration and spider size.Despite the increase in detectability,incorporating a conspicuous cruciform decoration to the web effectively defends the spider by diverting the attack toward the decoration or leg,but not by camouflaging or intimidating,thus,supporting the deflection hypothesis.

关 键 词：Argiope minuta cruciform decoration predator deflection visual defense visual modeling 

分 类 号：Q95[生物学—动物学]