Influence of male density on guarding behaviour in the water strider Aquarius paludum (Heteroptera: Gerridae)

Atsuo Matsueda,Kenji Fujisaki

doi:10.14411/eje.2011.077

Abstract

In species with last sperm precedence, post-mating guarding behaviour by males is effective for avoiding sperm displacement by additional males. However, for males to guard their mates under all circumstances may be undesirable, particularly when the population density of conspecific rival males is low. To better understand the effects of rival density on mate guarding behaviour, we compared post-copulatory behaviour in males artificially subjected to different male densities using Aquarius paludum. Our results indicate that males of A. paludum modulate their post-copulatory behaviour based on previously experienced rival densities.

Highlights

The males of many insect species use a variety of tactics to ensure the paternity of offspring
No males dismounted from a female voluntarily, the frequency of males that persisted in post-copulatory guarding behaviour decreased as the isolation period increased
The length of the isolation period had no influence on the duration to first mating attempt (Fig. 1)

Summary

INTRODUCTION

The males of many insect species use a variety of tactics to ensure the paternity of offspring. The model proposed by Yamamura (1986) suggests that for males to guard their mates is not necessarily adaptive, when the population density of rivals (i.e., the male ratio) is low. Consistent with this hypothesis, previous studies have demonstrated that mate guarding behaviour is influenced by the sex ratio in several species (Jablonski & Vepsäläinen, 1995; Muse & Ono, 1996; Wada et al, 1999; Saeki et al, 2005b). The mating behaviour of water striders is easy to observe because it follows a well established sequence, including the male mating attempt, pre-mating struggle, copulation, post-mating struggle and post-mating guarding behaviour (Amano & Hayashi, 1998). The latter behaviour is reflected by male resistance to female struggling, i.e., may reflect male post-copulatory persistence

MATERIAL AND METHODS

Findings

DISCUSSION