Geographic variation in plasticity in Eristalis arbustorum |
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Authors: | Mart M Ottenheim Anja Henseler Paul M Brakefield |
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Institution: | Institute of Evolutionary and Ecological Sciences, Section of Evolutionary Biology and Systematics, Leiden University, P.O. Box 9516, 2300 RA Leiden, The Netherlands |
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Abstract: | To study the evolution of phenotypic plasticity in the field, six populations of the hoverfly Eristalis arbustorum were sampled along two parallel North-South transects over a maximum daily temperature gradient. Three populations were sampled per transect. Egg batches were collected and the offspring were reared in a split family set up over three different pupal temperature regimes in the laboratory to produce population reaction norms of colour pattern, pupal development time, wing length and thorax length. Wing length and colour pattern were corrected for body size. All four characters showed plasticity in response to rearing temperature and significant differences in height, slope and shape of the reaction norms were found. Only male colour pattern showed variation in reaction norms along the North-South gradient. Most other characters showed variation in reaction norms from West to East. The two populations lying in the middle of the transects were frequendy different from the others. Within the populations, significant genotype-environment interactions were frequently found for wing length and colour pattern, indicating that genetic variation for plasticity was present. The results suggest that the populations may have evolved plastic responses to suit local environmental conditions. |
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Keywords: | colour pattern development time hoverflies phenotypic plasticity thorax length Syrphidae wine length |
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