The parasite-host relationship between Encarsia formosa Gahan (Hymenoptera, Aphelinidae) and Trialeurodes vaporariorum (Westwood) (Homoptera, Aleyrodidae). 19. Feeding-site selection by the greenhouse whitefly.
1986
Noldus L.P.J.J. | Rumei X. | Lenteren J.C. van
During feeding-site selection on a tomato plant, adult greenhouse whiteflies, Trialeurodes vaporariorum, do not distinguish between leaves of different age from a distance. Selection occurs after landing on the leaf, and a strong preference for young leaves is shown. Transferring a whitefly from a young leaf to an old leaf or vice versa leads to significant changes in behaviour: on the young leaf more is spent probing (including feeding) and less time walking. Rejection of an old leaf occurs sooner if an insect has previous experience on a young leaf: inexperienced females depart from the leaf after on an average 6 probes of 3 min each; experienced females leave on an average after 3 probes of 2 min each. Young leaves have a higher content of soluble as well as protein nitrogen, compared with old leaves, so the preference may have adaptive value. Possible mechanisms which might enable feeding-site selection in the greenhouse whitefly are discussed. This includes the nature of the stimuli involved (physical, chemical) as well as the part of the leaf where those stimuli originate from (phloem contents, mesophyl, leaf surface).
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