Territoriality and malebiased sexual size dimorph

Authors: Rhainer GuillermoFerreira Kleber DelClaro

Publish Date: 2011/10/13

Volume: 15, Issue: 1, Pages: 101-105

PDF Link

Abstract

In Odonata many species present sexual size dimorphism SSD which can be associated with male territoriality in Zygoptera We hypothesized that in the territorial damselfly Argia reclusa male–male competition can favor large males and consequently drive selection pressures to generate malebiased SSD The study was performed at a small stream in southeastern Brazil Males were marked and we measured body size and assessed the quality of territories We tested if larger territorial males a defended the best territories those with more male intrusions and visiting females b won more fights and c mated more Couples were collected and measured to show the occurrence of sexual size dimorphism Results indicated that males are larger than females and that territorial males were larger than nonterritorial males Larger territorial males won more fights and defended the best territories There was no difference between the mating success of large territorial and small nonterritorial males Although our findings suggest that male territoriality may play a significant role on the evolution of sexual size dimorphism in A reclusa we suggest that other factors should also be considered to explain the evolution of SSD in damselflies since nonterritorial males are also capable of acquiring matesWe thank Frederico Lencioni for insect identification and Everton TizoPedroso Pitágoras Bispo and two anonymous referees for valuable comments We also thank the Universidade de São Paulo–FFCLRP for logistic support K DelClaro and R GuillermoFerreira thank CNPq for financial support grant/PQ and for a doctoral fellowship respectively

Keywords: