scholarly journals Sex Ratios under Asymmetrical Local Mate Competition: Theory and a Test with Parasitoid Wasps

2005 ◽  
Vol 166 (3) ◽  
pp. 301-316 ◽  
Author(s):  
David M. Shuker ◽  
Ido Pen ◽  
Alison B. Duncan ◽  
Sarah E. Reece ◽  
Stuart A. West
Keyword(s):  
Sex Ratios ◽  
Local Mate Competition ◽  
Parasitoid Wasps ◽  
Mate Competition ◽  
Competition Theory ◽  
Local Mate

scholarly journals Cooperative interactions among females and even more extraordinary sex ratios

2020 ◽  
Author(s):  
Ryosuke Iritani ◽  
Stuart A West ◽  
Jun Abe
Keyword(s):  
Sex Ratio ◽  
Sex Ratios ◽  
Structured Populations ◽  
Local Mate Competition ◽  
Mate Competition ◽  
Wasp Species ◽  
Cooperative Interactions ◽  
Competition Theory ◽  
Local Mate ◽  
Biased Sex Ratio

AbstractHamilton’s local mate competition theory provided an explanation for extraordinary female biased sex ratios in a range of organisms. When mating takes place locally, in structured populations, a female biased sex ratio is favoured to reduce competition between related males, and to provide more mates for males. However, there are a number of wasp species where the sex ratios appear to more female biased than predicted by Hamilton’s theory. We investigated theoretically the extent to which cooperative interactions between related females can interact with local mate competition to favour even more female biased sex ratios. We found that: (i) cooperative interactions between females can lead to sex ratios that are more female biased than predicted by local competition theory alone; (ii) sex ratios can be more female biased when the cooperative interactions are offspring helping parents before dispersal, rather than cooperation between siblings after dispersal. Our results can be applied to a range of organisms, and provide an explanation for the extreme sex ratio biases that have been observed in Sclerodermus and Melittobia wasps.

scholarly journals Primary and secondary sex ratios in a gregarious parasitoid with local mate competition

2012 ◽  
Vol 24 (2) ◽  
pp. 435-443 ◽  
Author(s):  
Sahand K. Khidr ◽  
Sean Mayes ◽  
Ian C.W. Hardy
Keyword(s):  
Sex Ratios ◽  
Local Mate Competition ◽  
Mate Competition ◽  
Local Mate ◽  
Gregarious Parasitoid

Study on mating ecology and sex ratio of three internally ovipositing fig wasps of Ficus curtipes

2009 ◽  
Vol 100 (2) ◽  
pp. 241-245
Author(s):  
F.P. Zhang ◽  
D.R. Yang
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Mating Behaviour ◽  
Local Mate Competition ◽  
Mate Competition ◽  
Mating Pattern ◽  
Fig Wasps ◽  
Competition Theory ◽  
Male Dispersal ◽  
Local Mate

AbstractStudies on mating ecology and sex allocation in fig-parasitizing wasps ovipositing from outside the fig have given valuable insights into known factors that are responsible for the theory of sex ratio. Similarly, internally ovipositing fig-parasitizing wasps and fig-pollinating wasps provide interesting models for comparative analysis. In addition to the fig-pollinating wasp Eupristina sp., we found that Ficus curtipes hosts two species of internally ovipositing fig-parasitizing wasps: D. yangi and Lipothymus sp. Eupristina sp. males showed less aggression. Eupristina sp. has wingless males that mate only within the natal patch, providing excellent examples of full local-mate competition. D. yangi males showed high levels of aggression and lethal combat. D. yangi has winged males but mate mostly within the natal patch. Only a few matings occur after male dispersal. Its sex ratio was lower than the prediction of partial local mate competition theory. Wingless male Lipothymus sp., which mate partly after dispersal, did not present fatal fight. Therefore, the mating behaviour of D. yangi and Lipothymus sp. did not follow predicted patterns, based on wing morph. The mating pattern of D. yangi and Lipothymus sp. should follow the partial local mate competition theory. Furthermore, there was not a significant correlation between the proportion of males and the proportion of fruit parasitized in both winged D. yangi males and wingless Lipothymus sp. males.

scholarly journals Solving the sex ratio scandal in Melittobia wasps

2020 ◽  
Author(s):  
Jun Abe ◽  
Ryosuke Iritani ◽  
Koji Tsuchida ◽  
Yoshitaka Kamimura ◽  
Stuart A. West
Keyword(s):  
Sex Ratio ◽  
Sex Allocation ◽  
Laboratory Experiments ◽  
Sex Ratios ◽  
Local Mate Competition ◽  
Mate Competition ◽  
Offspring Sex ◽  
Local Mate ◽  
Close Relatives

AbstractThe scandalous sex ratio behaviour of Melittobia wasps has long posed one of the greatest problems for the field of sex allocation. In contrast to the predictions of theory, and the behaviour of numerous other organisms, laboratory experiments have found that Melittobia females do not produce less female-biased offspring sex ratios when more females lay eggs on a patch. We resolve this scandal, by showing that, in nature, females of M. australica have sophisticated sex ratio behaviour, where their strategy also depends upon whether they have dispersed from the patch where they emerged. When females have not dispersed, they will be laying eggs with close relatives, which keeps local mate competition high, even with multiple females, and so they are selected to produce consistently female-biased sex ratios. Laboratory experiments mimic these conditions. In contrast, when females disperse, they will be interacting with non-relatives, and so they adjust their sex ratio depending upon the number of females laying eggs. Consequently, females appear to use dispersal status as an indirect cue of relatedness, and whether they should adjust their sex ratio in response to the number of females laying eggs on the patch.

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