Intersexual conflict during mate guarding in an androdioecious crustacean

2012 ◽  
Vol 23 (1) ◽  
pp. 218-224 ◽  
Author(s):  
Chiara Benvenuto ◽  
Stephen C. Weeks
1994 ◽  
Vol 32 (3) ◽  
pp. 265-283 ◽  
Author(s):  
Veijo Jormalainen ◽  
Juha Tuomi ◽  
Norio Yamamura

2010 ◽  
Vol 7 (3) ◽  
pp. 333-335 ◽  
Author(s):  
Matthias Galipaud ◽  
François-Xavier Dechaume-Moncharmont ◽  
Abderrahim Oughadou ◽  
Loïc Bollache

Precopulatory mate guarding (PCMG) is generally assumed to be costly for both sexes. However, males may gain by displaying long-lasting mate guarding under strong male–male competition. Surprisingly, the potential for females to benefit from being held by males has been largely overlooked in previous studies. In Gammarus pulex , an amphipod crustacean, PCMG lasts several weeks, yet females are described as bearing only cost from such male mating strategy. We investigated potential female benefits by assessing the effect of mate guarding on her intermoult duration. Unpaired females had longer intermoult duration than paired females. Intermoult duration clearly decreased when paired females engaged in early and long-lasting mate guarding. In addition, short intermoults and long-lasting mate guarding had no effect on egg number. These results highlight a potential benefit associated with PCMG for G. pulex females, suggesting that the strength of an intersexual conflict over its duration may be overestimated.


Author(s):  
Abraham P. Buunk ◽  
Karlijn Massar ◽  
Pieternel Dijkstra ◽  
Ana María Fernández

This chapter discusses sex differences in intersexual competition and describes particularly the consequences of such competition for conflict between the sexes, as well as for sex differences in mate guarding and, relatedly, in the types of infidelity that evoke jealousy, including online infidelity. It also discusses individual differences in jealousy as related to attachment styles and describes the effects of height, hormones, and the menstrual cycle on jealousy. Next, the chapter moves on to intrasexual competition and discusses, among other topics, intrasexual competition among men and among women, the role of sex differences in rival characteristics in evoking jealousy, the role of attachment styles and hormones, and individual differences in intrasexual competitiveness.


Behaviour ◽  
1996 ◽  
Vol 133 (13-14) ◽  
pp. 985-996 ◽  
Author(s):  
Jaimie T.A. Dick ◽  
Robert W. Elwood

AbstractWe employed field-based studies, with complementary laboratory-based studies, to investigate social and environmental influences on tactical mate-guarding decisions in amphipods (Crustacea). Firstly, we investigated variation in precopulatory mate-guarding duration in Cammarus duebeni celticus in relation to the social structure of natural populations. Variation in population density of up to two orders of magnitude had no effect on precopula duration, whereas guarding durations increased as the sex ratios of the populations became more male biased. That is, males have some ability to assess the probability of other males taking females into precopula and are prepared to guard for longer as this threat of male: male competition increases. A field demonstration of tactical shifts in reproductive behaviour in response to pertinent social conditions is thus provided. Secondly, the 'habitat segregation' hypothesis, which proposes that positive size-assortative pairing in amphipod populations arises due to variation in the use of micro-habitats, was tested in natural field populations and under laboratory conditions in Echinogammarus marinus. This was necessary in order to distinguish any purely environmental determinants of size-assortment from the role of active decisions by males concerning mate choice and male: male competition. The hypothesis was rejected on the grounds that size-assortative pairing arises under both heterogeneous and homogeneous environmental conditions. Further, in both study species, male and female body size were positively correlated with precopula duration. Thus, indirect competition for access to large, fecund females, based on the timing of male entry into precopula, together with direct aggression, provides the explanation for size-assortative pairing in amphipods.


2009 ◽  
Vol 6 (2) ◽  
pp. 180-182 ◽  
Author(s):  
Richard N. C. Milner ◽  
Michael D. Jennions ◽  
Patricia R. Y. Backwell

In fiddler crabs both males and females defend territories that are essential for survival. Given pronounced sexual dimorphism in weaponry, how do weaponless females defend their territory from well-armed males? Using observational data and two simple experiments, we test whether male Uca annulipes protect their female neighbours from conspecific intruders. We show that males defend their female neighbours against male but not female intruders. We also show that females sometimes mate with their immediate neighbours. Male defence of female neighbours appears to represent both pre-copulatory mate-guarding and a territorial coalition. Males who ensure that their neighbour remains female could benefit through increased opportunity for future reproductive success and lower boundary maintenance costs.


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