Strategic adjustment of copulatory plug size in a nematode  

作　　者：Jorge Canales-LAZCANO Jorge Contreras-GARDUNO Carlos CORDERO 

机构地区：[1]Posgrado en Ciencias Biomedicas,Institute)de Ecologia,UNAM,Circuito Exterior S/N,anexo al Jardfn Botanico exterior,Ciudad Universitaria,Ciudad de Mexico,Mexico [2]Escuela Nacional de Estudios Superiores,Universidad Nacional Autonoma de Mexico,Unidad Morelia,Antigua Carretera a Patzcuaro No.8701,Col.Ex-Hacienda San Jose de la Huerta,Morelia,Michoacan,Mexico [3]Departamento de Ecologia Evolutiva,Instituto de Ecologla,UNAM,Circuito Exterior S/N,anexo al Jardin Botanico exterior,Ciudad Universitaria,Ciudad de Mexico,Mexico

出　　处：《Current Zoology》2019年第5期571-577,共7页动物学报（英文版）

摘　　要：Copulatory plugs(CP)are substances produced during copulation that block the genital openings of the female.In several species of Nematoda,males produce CP that are thought to impede female remating and thus sperm competition.The relatively large size of the CP in several nematodes,and its evolutionary loss in self-fertilizing populations of Caenorhabditis elegans,suggests that CP are costly to produce.If CP production is costly,the application of basic concepts of strategic ejaculation theory suggests a modulated allocation of CP in response to sperm competition risk.This hypothesis led us to predict that males perceiving a higher risk of sperm competition will produce larger CP.We tested these ideas with the entomopathogenic,gonochoristic nematode Rhabditis regina.Our first experiment provides evidence suggesting that production of CP is costly,because the size of CP is negatively affected by stressful conditions(high population density,small male adult size,and suboptimal food type).The results of our second experiment support the prediction that males adjust the size of CP to sperm competition risk:the average size of CP increased as the number of males competing for one female increased.Overall,our study supports the idea that in R.regina the production of CP is costly for males and that the size of the CP produced is influenced by sperm competition risk.

关 键 词：copulatory PLUG sexual selection SPERM COMPETITION STRATEGIC EJACULATION nematodes 

分 类 号：F42[经济管理—产业经济]