Searching speed of Trichogramma minutum and its potential as a measure of parasitoid quality

Searching speed has been proposed as a quality criterion for the prediction of held efficacy of mass-reared Trichogramma spp. The searching speed, wal king speed, and activity of female T. minutum Riley were measured using an automated video tracking system. Two- and 3-day-old thelytokous females sea rched twice as fast as 1-day-old females, whereas the searching speed of a strain of arrhenotokous females was similar at all ages. When reared on Act ebia fennica Tauscher, the resulting wide variation in wasp size was not re lated to searching speed or walking speed. Both strains of II minutum searc hed faster later in the day. In a second laboratory experiment, the proport ion of hosts parasitized, the proportion of hosts accepted, and searching s peeds of parasitoids were measured simultaneously for groups of females of both strains. Percentage parasitism was related to host acceptance but not searching speed. Searching speed was unrelated to the estimated number of h ost contacts. These results suggest that searching speed is not a useful me asure of parasitoid efficacy for T. minutum. (C) 2000 Academic Press.