Abstract

Intraguild predation (IGP) contains elements of competition and predation, whereby the competitors can kill each other. The non-native predatory mite Neoseiulus californicus and two native predatory mites Typhlodromus bagdasarjani and Phytoseius plumifer are considered as appropriate candidates for controlling spider mites in greenhouses and they may applied at the same time to boost the control effect on the two spotted spider mite Tetranychus urticae. Consequently, they are food competitors and potential IGP among the three predator species can mitigate or interrupt the biological control success of the predators on the spider mites. Thus, we checked the ability of the three predatory mite species to prey on larvae of each other [the intraguild (IG) prey] in the presence of the extraguild (EG) prey Tetranychus urticae. Adult females of each predatory species were individually placed into closeable cages and were provided with 6 larvae per IG prey species (IG prey), and 12 immatures of T. urticae (EG prey) over 4 days. At each day the cages were checked every 30 min over a period of 480 min for the first attack on IG or EG prey. Predation rateswere recorded every 24 h. All three predators preferred to attack EG prey at first and also consumed more EG than IG prey. Females of N. californicus attacked significantly faster EG than IG prey larvae, whereas the attack times on IG and EG prey larvae were non-significant for T. bagdasarjani and P. plumifer females. The predator species had no influence on the consumption rates and attack times on the IG prey larvae. Hence based on these preliminary results, IGP among the three predatory mite species seems to be low in the presence of the EG prey, however, further experiments are needed to evaluate the effects of IGP among the three species on population level.