Adult D. speciosa Bioassays

The responses of adult D. speciosa to treated and untreated corn plants were evaluated in two-choice Y-tube glass olfactometers (Fig. 2d). Aboveground portions of plants with the desired treatments were placed in glass chambers where filtered, humidified air was introduced then pumped via teflon tubes to the olfactometer, one treatment per arm. Adult D. speciosa were introduced at the base of the Y-tube olfactometer and allowed five minutes to choose an arm; response time and treatment choice were monitored. Treatments were rotated every three insects to avoid positional effect. Ten replications of each treatment combination were conducted with each replicate consisting of ten insect choices. Clean glassware and new plants were used for each replicate.

Treatment combinations consisting of undamaged, mechanically damaged, pest damaged, and elicitor untreated and treated plants were used to determine the effect of plant defense pathway stimulation on D. speciosa response. Twenty day old corn seedlings were used in all experiments; undamaged corn seedlings were taken directly from the greenhouse 20 days after germination and immediately used in the experiment. Mechanically damaged corn seedlings were cut with a scalpel using a template replicating foliar damage by adult D. speciosa 48 hours prior to use in the experiment. Pest damaged plants were fed upon by five adult D. speciosa placed in mesh bags on the foliage of each plant 48 hours prior to use in the experiment. Elicitor treated (either methyl salicylate or methyl jasmonate) plants were treated 48 hours prior to use in experiments.