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Life-history and oviposition behaviour of Amitus bennetti, a parasitoid of Bemisia argentifolii

Drost, Y.C., Qui, Y.T., Posthuma-Doodeman, C.J.A.M., Lanteren, J.C. van.
Entomologia experimentalis et applicata 1999 v.90 no.2 pp. 183-189
parasitoids, oviposition, longevity, biological control agents, Amitus, Bemisia argentifolii, ambient temperature, heat sums, fecundity, host preferences, biological development, life cycle (organisms)
Amitus bennetti Viggiani & Evans (Hymenoptera: Platygasteridae) is a recently described parasitoid of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae). Behaviour and life history of the parasitoid are described. The first nymphal instar of B. argentifolii is preferred by the parasitoid, but the 1st through 4th instar may be parasitised. Females first investigate hosts with their antennae, then walk over the host, and eventually step with their front legs on the leaf and insert their ovipositor inside the host facing away from the host, while the hind legs are still on the host. The time from encounter to oviposition (= latency to oviposition) is shortest on the 1st instar. Oviposition duration (mean = 39 s) comprises 50% of the handling time. Development time from egg to adult decreases from 72 days at 15 degrees C to 42 days at 20 degrees C to 28 days at 25 degrees C. We estimate that 400 degree days is required for development, with a development threshold of 10 degrees C. Adult longevity in the absence of hosts was 29, 26 and 19 days and with hosts present 8, 8 and 5 days at 15, 20 and 25 degrees C, respectively. Amitus bennetti is proovigenic and oviposits most eggs shortly after adult emergence. During the first day of their adult lives female laid 1, 31 and 49 eggs at 15, 20 and 25 degrees C, respectively. Compared with other parasitoid species, the development time of A. bennetti is very long, and the implications of this for management of B. argentifolii are discussed.