Activity, feeding, and development among larvae of specialist and generalist phytoseiid mite species (Acari: Phytoseiidae)

Feeding, development, activity, and other behaviors were assessed among larvae of 13 representative specialist and generalist phytoseiid mite species. Larval feeding types were not associated with degree of specialization. Obligatory-, facultative-, and nonfeeding larvae occurred in highly selective predators as well as in polyphages. Larvae of Phytoseiulus persimilis Athias-Henriot, P. macropilis (Banks), Kampimodromus aberrans Oudemans, Neoseiulus longispinosus (Evans), N. cucumeris (Oudemans), N. barkeri Hughes, and Typhlodromus pyri Scheuten are non-feeders; larvae of N. fallacis (Garman),N. californicus (McGregor), and Amblyseius andersoni Chant are facultative feeders; and larvae of Galendromus occidentalis (Nesbitt), Euseius finlandicus (Oudemans), and E. hibisci (Chant) are obligatory feeders. Nonfeeding P. persimilis, P. macropilis, and IC aberrans larvae developed fastest. Obligatory-feeding E. finlandicus and E. hibisci larvae developed slowest. With food, larvae of most species rested after some initial activity, whereas obligatory-feeding larvae of both Euseius species frequently moved throughout the stage. Without food, obligatory-feeding larvae and facultative-feeding N. fallacis larvae were most active. Regardless of larval feeding type, larvae without food walked more and developed slower than those with food. Jerking was defined as an avoidance response and was most frequent in N. fallacis larvae but absent in larvae of K aberrans and N barkeri and obligatory-feeding larvae. Profiles of larval traits are provided for each species. Factors leading to specific larval life histories and taxonomic associations of larval feeding types are discussed.