BEHAVIORAL, MORPHOLOGICAL, AND PHYSIOLOGICAL TRAITS ASSOCIATED WITH MIGRATORY BEMISIA-TABACI (HOMOPTERA, ALEYRODIDAE)

Bemisia tabaci, that were flown for varying lengths of time (1 min-2.5 h), exhibited behavioral, morphological, and physiological difference s. When whiteflies that were engaging in phototactic orientation in a vertical flight chamber were presented with a visual cue simulating th eir host plant (550-nm narrowband interference filter), 76% landed on this cue within three presentations. Another 18% of the whiteflies dis played an intermittent attraction to the host cue, and 6% displayed a response that, historically, has been considered to be indicative of m igration. These individuals failed to respond to the target until they had flown for at least 15 min, These three categories of response wer e observed in both sexes, in all flight-capable individuals from 1 to 5 days old and in two groups of whiteflies that were exhibiting distin ct behaviors prior to our tests (i. e., they were either settled on po insettia or engaging in phototactic orientation). There was a trend fo r males that engaged in long-distance flight to have smaller wing dime nsions than males that engaged in shorter flights; no trend was eviden t in female whiteflies. High levels of vitellogenin and vitellin did n ot inhibit Fight activity. In fact, we generally found higher levels o f egg proteins in long-distance fliers and in premigratory individuals than in short-duration fliers and settled individuals.