Population differentiation in the grasshopper Sinipta dalmani: Body size varies in relation to karyotype and climatic conditions
Sinipta dalmani is an Argentine grasshopper whose chromosome polymorphisms have been widely studied through cytogenetic and fitnesscomponent analyses. This paper reviews the available information on its body-size variations as they relate to differences between sexes, karyotype and mating success, a...
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_10826467_v17_n2_p213_Remis |
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| Sumario: | Sinipta dalmani is an Argentine grasshopper whose chromosome polymorphisms have been widely studied through cytogenetic and fitnesscomponent analyses. This paper reviews the available information on its body-size variations as they relate to differences between sexes, karyotype and mating success, and shows a preliminary analysis of a pattern of geographic variation. A significant body-size sexual dimorphism was evident, with females being significantly larger than males. Polymorphic populations for M4 pericentric inversion showed considerable variation in both adult male and adult female sizes, a variation in part related to this chromosomal rearrangement, which has a negative effect on body size. Simultaneous cytogenetic, morphometric and fitness analyses showed direct evidence of phenotypic directional selection within populations favoring larger males and smaller females. The patterns of body-size differentiation among populations in relation to geographic conditions suggest local adaptation. Our results in S. dalmani demonstrate significant variation in body size within polymorphic populations and among geographical populations, which may be explained under a selective scenario. |
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