When host choice is a problem for a generalist herbivore: experiments withthe whitefly, Bemisia tabaci

1. Experiments with adult females of the whitefly, Bemisia tabaci, demonstr ated that when mixtures of host plants were present, performance was reduce d relative to that on the best of the host plants when presented alone. 2. Behavioural observations indicated that in the presence of a variety of plants, individuals moved more, switched between plants more frequently, an d stayed feeding in one place for shorter periods of time, compared with th e situation when single plant species were available. 3. The data are interpreted as a constraint on attentiveness in the presenc e of complex, mixed-sensory stimuli.