Behavioral,morphological, and physiological traits associated with migratoryBemisia tabaci (Homoptera: Aleyrodidae)

Bemisia tabaci, that were flown for varying lengths of time (1 min-2.5 h), exhibited behavioral, morphological, and physiological differences. When whiteflies that were engaging in phototactic orientation in a vertical flight chamber were presented with a visual cue simulating their host plant (550-nm narrowband interference filter), 76% landed on this cue within three presentations. Another 18% of the whiteflies displayed an intermittent attraction to the host cue, and 6% displayed a response that, historically, has been considered to be indicative of migration. These individuals failed to respond to the target until they had flown for at least 15 min. These three categories of response were observed in both sexes, in all flight-capable individuals from 1 to 5 days old and in two groups of whiteflies that were exhibiting distinct behaviors prior to our tests (i.e., they were either settled on poinsettia or engaging in phototactic orientation). There was a trend for males that engaged in long-distance flight to have smaller wing dimensions than males that engaged in shorter flights; no trend was evident in female whiteflies. High levels of vitellogenin and vitellin did not inhibit flight activity. In fact, we generally found higher levels of egg proteins in long-distance fliers and in premigratory individuals than in short-duration fliers and settled individuals.