Tetranychus urticae changes its oviposition pattern in the presence of the predatory mites, Phytoseiulus persimilis and Typhlodromus bagdasarjani

Abstract

Oviposition behaviors in herbivorous mites are affected by several factors i.e. food availability for juveniles and reduced predation risks. We used the twospotted spider mite, Tetranychus urticae Koch (Tetranychidae) to find out whether the previous presence of specialist/ generalist phytoseiid predator individuals, Phytoseiulus persimilis Athias-Henriot/ Typhlodromus bagdasarjani Wainstein & Arutunjan (here, direct effect) or their previous odour perception by prey (here, indirect effect) would affect T. urticae oviposition strategies. Tetranychus urticae female individuals were placed on a leaf disc in a plastic container with predators either on the same disc (direct presence of predator) or on the second disc (receiving odours related to a predator) in the same container. Getting experienced, the prey individuals transferred to the oviposition container to their oviposition pattern parameters get recorded. The ovipositing T. urticae were monitored in two experimental situations: 1. Receiving odours related to the predator- prey interaction from the second leaf disc in the same oviposition container during their oviposition period, and 2. Receiving no odour. Our results showed that when T. urticae females perceived the predator presence in their first container (with either predator species, both direct and indirect effect), they reduced their total egg distances, oviposition rates and oviposition periods significantly regardless of receiving odours related to prey-predator interactions during experiment. Receiving odours during oviposition, T. urticae females decreased their pairwise egg distances in at least 4 and at most 6 pairs of eggs, while when odours were absent during oviposition, the distances decreased in at least 2 and at most 3 pairs of eggs. The direct presence of P. persimilis reduced the prey oviposition period significantly more than that when T. bagdasarjani was present. The spider mites oviposition rate reduction was obviousely more than that in the presence of T. bagdasarjani. The different effects of predator species on T. urticae egg distances were discussed.

Keywords

• oviposition
• spider mite
• predation
• parental care
• Phytoseiidae