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Local mate competition with lethal male combat: effects of competitive asymmetry and information availability on a sex ratio game
Author(s) -
Abe J.,
Kamimura Y.,
Ito H.,
Matsuda H.,
Shimada M.
Publication year - 2003
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1046/j.1420-9101.2003.00558.x
Subject(s) - biology , sex ratio , competition (biology) , sex allocation , mating , evolutionarily stable strategy , parasitoid , stackelberg competition , nash equilibrium , parasitoid wasp , sperm competition , ecology , game theory , microeconomics , hymenoptera , demography , economics , population , sociology
We constructed a sex allocation model for local mate competition considering the asymmetry of competitive abilities among sons. This model assumes two females of a parasitoid wasp oviposit on the same host in sequential order. The evolutionarily stable strategy will be in either Stackelberg or Nash equilibrium, depending on whether the females can recognize their opponent's sex ratio or not, respectively. The Nash equilibrium predicts the second female produce more males than the first. If the second female is able to know and respond to the strategy of the first (a Stackelberg equilibrium), the first will decide an optimal sex ratio assuming that the second reply to it. Under such an assumption, our model predicts that not producing sons is adaptive for the second female when the sons she produces have low competitive ability. Males of parasitoid wasps Melittobia spp. are engaged in lethal male–male combat, indicating large asymmetry in mating success among sons. If females have the ability to recognize their opponent's sex ratio, our model suggests that the severe lethal male–male combat may be one factor explaining their extremely female‐biased sex ratio that is unexplainable by pre‐existent models.