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Non-quantitative adjustment of offspring sex ratios in pollinating fig wasps.

Wang RW, Sun BF, He JZ, Dunn DW - Sci Rep (2015)

Bottom Line: The foundresses tend to deposit their male eggs prior to female eggs.The observed increase in the proportion of male offspring as a function of foundress number results from density-dependent interference competition among the foundresses.The results here implied that genetic adjustment mechanisms of the sex ratio of fig wasps can only be triggered to be on or off and that the foundresses can not quantitatively adjust their sex ratio according to increased environmental selection pressure.

View Article: PubMed Central - PubMed

Affiliation: Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an, 710072, China.

ABSTRACT
Fig wasp is one of the most well known model systems in examining whether or not the parents could adjust their offspring sex ratio to maximize their gene frequency transmission in next generations. Our manipulative experiments showed that, in all of the five pollinator wasps of figs (Agaonidae) that have different averages of foundress numbers per syconium, almost the same proportions of male offspring are produced in the experiment that foundresses deposit one hour then are killed with ether (66.1%-70.1%) and over the lifespan of each foundress (14.0%-21.0%). The foundresses tend to deposit their male eggs prior to female eggs. The observed increase in the proportion of male offspring as a function of foundress number results from density-dependent interference competition among the foundresses. These results showed that the selection of gene frequency transmission through the behavioral adjustment in the evolution of sex ratio does not exist in these five fig wasps. The results here implied that genetic adjustment mechanisms of the sex ratio of fig wasps can only be triggered to be on or off and that the foundresses can not quantitatively adjust their sex ratio according to increased environmental selection pressure.

No MeSH data available.


Related in: MedlinePlus

Offspring sex ratio (male offspring/total offspring number) of pollinator wasps at different ovipositing periods in five fig species (mean ± SD).(a) F. racemosa pollinated by C. fusciceps; (b) F. hispida pollinated by C. solmsi; (c) F. benjamina pollinated by E. koningsbergeri; (d) F. semicordata pollinated by C. gravelyi; (e) F. auriculata pollinated by C. emarginatus. The sample size N ≥ 20 in each type of the experiments.
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f1: Offspring sex ratio (male offspring/total offspring number) of pollinator wasps at different ovipositing periods in five fig species (mean ± SD).(a) F. racemosa pollinated by C. fusciceps; (b) F. hispida pollinated by C. solmsi; (c) F. benjamina pollinated by E. koningsbergeri; (d) F. semicordata pollinated by C. gravelyi; (e) F. auriculata pollinated by C. emarginatus. The sample size N ≥ 20 in each type of the experiments.

Mentions: The interference competition impact has been showed to be density-dependent and the interference competition that decreases the female egg deposition will be non-linearly amplified as a function of foundress number1516. The sex ratio would be expected to increase to over the 50% male offspring level after the foundress number reaches a threshold in which interference competition among the foundresses was very high and the sex ratio should be same ratio in the first minute/hour of egg deposition in each foundress (i.e. male offspring proportion will be about 70% when the foundress number is very high, see Fig. 1). We therefore designed the simultaneous introduction of pollinators of F. racemosa with 1, 3, 5, 7, 9, 15, 20, 30, 40, 70 foundresses per syconium to examine whether the sex ratio would increase to over 50% after the foundress number had reached a certain threshold.


Non-quantitative adjustment of offspring sex ratios in pollinating fig wasps.

Wang RW, Sun BF, He JZ, Dunn DW - Sci Rep (2015)

Offspring sex ratio (male offspring/total offspring number) of pollinator wasps at different ovipositing periods in five fig species (mean ± SD).(a) F. racemosa pollinated by C. fusciceps; (b) F. hispida pollinated by C. solmsi; (c) F. benjamina pollinated by E. koningsbergeri; (d) F. semicordata pollinated by C. gravelyi; (e) F. auriculata pollinated by C. emarginatus. The sample size N ≥ 20 in each type of the experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543974&req=5

f1: Offspring sex ratio (male offspring/total offspring number) of pollinator wasps at different ovipositing periods in five fig species (mean ± SD).(a) F. racemosa pollinated by C. fusciceps; (b) F. hispida pollinated by C. solmsi; (c) F. benjamina pollinated by E. koningsbergeri; (d) F. semicordata pollinated by C. gravelyi; (e) F. auriculata pollinated by C. emarginatus. The sample size N ≥ 20 in each type of the experiments.
Mentions: The interference competition impact has been showed to be density-dependent and the interference competition that decreases the female egg deposition will be non-linearly amplified as a function of foundress number1516. The sex ratio would be expected to increase to over the 50% male offspring level after the foundress number reaches a threshold in which interference competition among the foundresses was very high and the sex ratio should be same ratio in the first minute/hour of egg deposition in each foundress (i.e. male offspring proportion will be about 70% when the foundress number is very high, see Fig. 1). We therefore designed the simultaneous introduction of pollinators of F. racemosa with 1, 3, 5, 7, 9, 15, 20, 30, 40, 70 foundresses per syconium to examine whether the sex ratio would increase to over 50% after the foundress number had reached a certain threshold.

Bottom Line: The foundresses tend to deposit their male eggs prior to female eggs.The observed increase in the proportion of male offspring as a function of foundress number results from density-dependent interference competition among the foundresses.The results here implied that genetic adjustment mechanisms of the sex ratio of fig wasps can only be triggered to be on or off and that the foundresses can not quantitatively adjust their sex ratio according to increased environmental selection pressure.

View Article: PubMed Central - PubMed

Affiliation: Center for Ecological and Environmental Sciences, Northwestern Polytechnical University, Xi'an, 710072, China.

ABSTRACT
Fig wasp is one of the most well known model systems in examining whether or not the parents could adjust their offspring sex ratio to maximize their gene frequency transmission in next generations. Our manipulative experiments showed that, in all of the five pollinator wasps of figs (Agaonidae) that have different averages of foundress numbers per syconium, almost the same proportions of male offspring are produced in the experiment that foundresses deposit one hour then are killed with ether (66.1%-70.1%) and over the lifespan of each foundress (14.0%-21.0%). The foundresses tend to deposit their male eggs prior to female eggs. The observed increase in the proportion of male offspring as a function of foundress number results from density-dependent interference competition among the foundresses. These results showed that the selection of gene frequency transmission through the behavioral adjustment in the evolution of sex ratio does not exist in these five fig wasps. The results here implied that genetic adjustment mechanisms of the sex ratio of fig wasps can only be triggered to be on or off and that the foundresses can not quantitatively adjust their sex ratio according to increased environmental selection pressure.

No MeSH data available.


Related in: MedlinePlus