Meeting Abstract

P3.4  Sunday, Jan. 6  The Effects of Abiotic Factors on Host Finding by Trichogramma Wasps VANATTA, K.J.*; POTTER, K.A.; WOODS, H.A.; Univ. of Montana; Univ. of Montana; Univ. of Montana kyle.vanatta@umontana.edu

Trichogramma wasps are important agents of biological control used commonly around the world in agricultural settings. Despite their importance, little is known about physical factors that affect their probability of finding and parasitizing host eggs. Using wild populations of T. deion and T. sathon, we examined the effects of three abiotic factors (temperature, humidity, & ultraviolet light) on patterns of adult movement and parasitization, using both choice and non-choice tests. In choice experiments that did not include host eggs, Trichogramma wasps showed greater preference for higher humidities and higher UV-B intensities. In some UV preference tests, the wasps preferred higher levels of UV-B but also were damaged by those levels. In non-choice experiments a higher proportion of Manduca sexta host eggs were parasitized in more moderate temperatures, higher humidities, and under higher intensities of UV-B. Further experimentation showed that Trichogramma were negatively affected by UV-B after being exposed to it during the entire larval and early pupal stages, leading to lower numbers of emerging adults. This study showed that abiotic factors had a strong influence on where the wasps went and how many eggs they parasitized. Because Trichogramma are small and difficult to track this approach helps to indicate the abiotic limits within which wasps prefer to stay, and within which they parasitize eggs successfully. The abiotic preferences and limits we found provide a way to define microhabitats in which T. deion and T. sathon actually forage in complex agricultural landscapes. With a greater understanding of where the wasps are foraging, we can better predict which pest species Trichogramma are best suited to control.