Dispersal behaviour of an intertidal aphid
In: Journal of Animal Ecology. Blackwell Science/British Ecological Society: Oxford. ISSN 0021-8790; e-ISSN 1365-2656, meer
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| Abstract |
(1) The young first instars of the apterous morphs of the saltmarsh aphid Pemphigus trehernei Foster are consistently photopositive. This response wanes with age, such that old first instars, and all subsequent stages including the adult, are photonegative. (2) A short period (30 min) of floating on sea-water reverses the normal light response of the young first instars, which become photonegative. They become photopositive again if kept on a dry surface for a further 30 min after the initial 30 min period on sea-water. (3) All stages tend to move upwards on a vertical surface. This geonegative response can be overruled by the negative or positive responses to light. (4) These observations are incorporated into a model scheme for the dispersal of the aphid. |
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