Adaptive learning in the foraging behavior of the predatory mite Phytoseiulus persimilis

Arthropod learning in the context of food acceptance and choice is commonly assumed to be adaptive but documentation of the adaptive value is scarce and lacking for true predators. We examined learning in juveniles of the predatory mite Phytoseiulus persimilis, which has a feeding preference for herbivorous spider mites but may use conspecific larvae as alternative prey. Adult predator females that had experienced conspecific larvae as prey during their juvenile phase attacked conspecific prey earlier than naïve predator females did. Shorter latency to attack of adult females did not depend on the length of exposure to alternative prey in the juvenile phase (24 h or whole juvenile phase). Experience decreased the predation rates of adult females but enhanced their survival chances when feeding on the alternative prey. The suggested proximate cause for enhanced survival of experienced females was greater energetic efficiency in foraging as compared with naïve females. Experience resulted in faster prey recognition and acceptance (indicated by shorter latency to attack) increasing prey profitability, and optimized daily predation rates. Ultimately, juvenile learning allows P. persimilis to better cope with shortage of the innately preferred spider mite prey.