scholarly journals Effect of local mate competition on fig wasp sex ratios

2006 ◽  
Vol 66 (2b) ◽  
pp. 603-610 ◽  
Author(s):  
R. A. S. Pereira ◽  
A. P. Prado
Keyword(s):  
Sex Ratio ◽  
Sex Ratios ◽  
Local Mate Competition ◽  
Mate Competition ◽  
Fig Wasp ◽  
Fig Wasps ◽  
Brood Sex Ratio ◽  
Local Mate ◽  
Female Bias ◽  
The Relationship

In fig wasps, mating takes place among the offspring of one or a few foundress mothers inside the fig from which mated females disperse to found new broods. Under these conditions, related males will compete with each other for mating and several studies have shown female bias in brood sex ratios as a response to Local Mate Competition (LMC). Studying Pegoscapus tonduzi which pollinates Ficus citrifolia in Brazil, we analysed the effect of LMC (number of foundresses) on the sex ratio of the offspring of pollinating wasps. The relationship between the foundress number and brood sex ratio qualitatively followed the theory, however the empirical sex ratio was more female biased than expected from theoretical values. The model for an optimal sex ratio considers that each foundress wasp contributes the same number of eggs to be bred and that the violation of this assumption may explain the lack of adjustment in relation to the theory.

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.

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 A solution to a sex ratio puzzle in Melittobia wasps

2021 ◽  
Vol 118 (20) ◽  
pp. e2024656118
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

The puzzling sex ratio behavior of Melittobia wasps has long posed one of the greatest questions in the field of sex allocation. Laboratory experiments have found that, in contrast to the predictions of theory and the behavior of numerous other organisms, Melittobia females do not produce fewer female-biased offspring sex ratios when more females lay eggs on a patch. We solve this puzzle by showing that, in nature, females of Melittobia australica have a sophisticated sex ratio behavior, in which their strategy also depends on whether they have dispersed from the patch where they emerged. When females have not dispersed, they lay eggs with close relatives, which keeps local mate competition high even with multiple females, and therefore, they are selected to produce consistently female-biased sex ratios. Laboratory experiments mimic these conditions. In contrast, when females disperse, they interact with nonrelatives, and thus adjust their sex ratio depending on 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.

Sex ratio response of the two-spotted spider mite (Tetranychus urticae Koch) to changes in density under local mate competition

1992 ◽  
Vol 70 (10) ◽  
pp. 1965-1967 ◽  
Author(s):  
C. M. Roeder
Keyword(s):  
Sex Ratio ◽  
Tetranychus Urticae ◽  
Local Mate Competition ◽  
Mate Competition ◽  
Local Mate ◽  
Theoretical Predictions ◽  
Female Bias ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch ◽  
Ratio Response

The progeny sex ratios produced by mothers in populations that are subject to local mate competition are often a function of the number of females ovipositing in a patch. When the number of colonizing females changes during oviposition, by immigration, emigration, or death, the predicted sex ratio should also change. This was tested by quantifying the sex ratio response of Tetranychus urticae females to changes in the number of ovipositing females in their patch. When a solitary female is accompanied by other ovipositing females after she has oviposited for a period of time, she decreases the female bias of her progeny after the other females arrive. A female ovipositing with patch mates that are removed after a period of time, increases her progeny female bias after the patch mates are removed. Both of these progeny sex ratio patterns are consistent with theoretical predictions, and constitute a response by mothers to mitigate competition for mates among her sons. Females ovipositing alone throughout their ovipositional period produce more males during the first half of their ovipositional period than during the latter period of oviposition. This pattern of male production is not evident when a female is ovipositing with four other females. Solitary mothers may produce more males early during oviposition in anticipation of other females arriving on their patch and ovipositing, a form of bet hedging. If no other females arrive, mothers compensate for their overproduction of males and invest more in females later during oviposition.

Sex allocation and local mate competition in Old World non-pollinating fig wasps

1999 ◽  
Vol 46 (2) ◽  
pp. 95-102 ◽  
Author(s):  
Mark D. E. Fellowes ◽  
Steve G. Compton ◽  
James M. Cook
Keyword(s):  
Sex Allocation ◽  
Local Mate Competition ◽  
Mate Competition ◽  
Fig Wasps ◽  
Old World ◽  
Local Mate
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