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Hasan Rahmani

Farid Borji, Hasan Rahmani, Peter Schausberger
Repeatability of aggressiveness against con- and heterospecific prey in the predatory mite Neoseiulus californicus (Acari: Phytoseiidae)
Abstract


We examined repeatability, i.e. the consistency with which a given trait is expressed, of aggressiveness against prey (i.e. attack latency) in gravid females of the predatory mite Neoseiulus californicus (McGregor). In two experiments, prey - conspecific individuals, the onion thrips Thrips tabaci (Lindeman), and the two-spotted spider mite Tetranychus urticae Koch- were repeatedly offered in various no-choice and choice situations. In the first experiment, the predators were offered conspecific larvae twice alone and then together with Te. urticae. In the second experiment, the predators were alternately offered Te. urticae and Th. tabaci in choice and no-choice situations. Latency to the first successful attack (resulting in death and consumption of prey) was recorded as aggressiveness. In the first experiment, Pearson’s r indicated that the predators were consistent in aggressiveness against conspecific prey. Additionally, latency to attack conspecific larvae and Te. urticae were strongly correlated when the former were offered alone and the latter were offered together with conspecific larvae. In the second experiment, aggressiveness against spider mites and thrips was inconsistent, non-repeatable and variable among contexts. However, Te. urticae was attacked more quickly when offered second after the first prey Th. tabaci than when offered as first prey. Both experiments in concert suggest that the level of behavioral consistency of N. californicus in aggressiveness against prey is strongly context-dependent. Further in-depth studies are needed to determine which foraging traits, and why and under which circumstances, are more repeatable than others.

 

 

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