Genetic variation in foraging traits among inbred lines of a predatory mite.
Response of predators to herbivore-induced plant volatiles can affect the length of time a predator spends in a prey patch and the probability of a predator finding a new prey patch. Variation in response to herbivore-induced plant volatiles may lead to different foraging decisions among individuals, thereby affecting both within-patch dynamics and between-patch dispersal. We found significant phenotypic and additive genetic variation in two behavioral assays of response to herbivore-induced plant volatiles among inbred isofemale lines of the predatory mite, Phytoseiulus persimilis. In wind-tunnel tests to measure patch residence time, adult female predators from certain lines left prey patches sooner than others when a distant source of herbivore-induced plant volatiles was presented; whereas such variation disappeared when no distant volatiles were presented. In a measure of patch location, certain lines were more likely than others to locate a prey-infested leaf disc; again there was no difference when uninfested leaf discs were used. Patch location was negatively correlated with patch residence. That is, lines that were more likely to leave a prey patch in the presence of distant volatiles were also more likely to find an odor source (ie, prey patch) from a distance of 20 cm. These two foraging-related behaviors are heritable. A continuous distribution of both behaviors indicated that several to many loci may be responsible for these behavioral traits. Our line-crossing experiments suggested that maternal influence could be excluded. Substantial phenotypic variation in two other foraging-related traits, consumption and oviposition, were also detected among inbred lines. Consumption and oviposition were positively correlated; however, the relationship (slope) varied among inbred lines, suggesting that predatory mites vary in food conversion efficiency. A relationship was detected between patch residence and consumption. Patch location, as one important foraging trait, appeared to be negatively related to consumption, suggesting a trade-off between searching for patches and reproduction.
Jia
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F
Department of Entomology, Kansas State University, Manhattan, KS 66506, USA. fjia@oznet.ksu.edu
Margolies
D C
DC
Boyer
J E
JE
Charlton
R E
RE
D000818:Animals; D001522:Behavior, Animal; D003433:Crosses, Genetic; D007887:Fabaceae / Q000378:metabolism / Q000469:parasitology; D005260:Female; D014644:Genetic Variation; D006790:Host-Parasite Interactions; D007178:Inbreeding; D008925:Mites / Q000502:physiology*; D010058:Oviposition / Q000502:physiology; D010641:Phenotype; D010675:Pheromones / Q000502:physiology*; D018515:Plant Leaves / Q000469:parasitology; D010946:Plants, Medicinal; D011157:Population Dynamics; D011235:Predatory Behavior; D014835:Volatilization
D010675:Pheromones