- The ratio of variance in male mating success (Vm) to variance in female mating success (Vf) is strongly male biased (Vm>Vf) in species P, strongly female biased in species Q (Vf>Vm) and similar in species R (Vm=Vf). All else being equal, which one of the following matches between species and mating systems is most likely?
(1) P-monogamy; Q-polyandry, R-polygyny
(2) P- polyandry; Q-polygyny, R-monogamy
(3) P-polygyny; Q-polyandry, R- monogamy
(4) P-monogamy; Q-polygyny, R-polyandry
Let’s consider three hypothetical species:
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Species P: Strongly male-biased variance in reproductive success (Vm>Vf)
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Species Q: Strongly female-biased variance in reproductive success (Vf>Vm)
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Species R: Similar variance in both sexes (Vm=Vf)
Given these patterns, which matches between species and mating systems is most likely?
Understanding Variance and Mating Systems
| Variance Pattern | Typical Mating System | Explanation |
|---|---|---|
| Vm>Vf | Polygyny | High male variance means a few males father most offspring, typical of polygynous systems |
| Vf>Vm | Polyandry | High female variance means a few females mother most offspring, seen in polyandrous systems |
| Vm=Vf | Monogamy | Similar variance means equal opportunity, typical of monogamous systems |
Why This Pattern?
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Polygyny: In polygynous species, a small number of males mate with many females, leading to high variance in male reproductive success and low variance in females.
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Polyandry: In polyandrous species, a small number of females mate with many males, leading to high variance in female reproductive success.
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Monogamy: In monogamous species, both sexes have similar opportunities to reproduce, resulting in similar variance.
Matching the Species
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P (Vm > Vf): Most likely polygyny
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Q (Vf > Vm): Most likely polyandry
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R (Vm = Vf): Most likely monogamy
Correct Option
(3) P-polygyny; Q-polyandry; R-monogamy
This match aligns with established evolutionary theory and empirical observations across animal taxa, where the direction and magnitude of reproductive variance reflect the underlying mating system.
Conclusion
When reproductive success is skewed toward males, polygyny is likely; when skewed toward females, polyandry prevails; and when variance is similar, monogamy is the norm. Understanding these patterns helps predict social structure and sexual selection in animal populations.
1 Comment
Kajal
October 13, 2025Polygyny, polyandry and monogamy