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SEXUAL SELECTION ON MATURATION TIME AND BODY SIZE IN SPHENARIUM PURPURASCENS (ORTHOPTERA: PYRGOMORPHIDAE): CORRELATED RESPONSE TO SELECTION
Author(s) -
Castillo Raúl Cueva,
NúñezFarfán J.
Publication year - 1999
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.1999.tb05346.x
Subject(s) - biology , voltinism , sexual selection , sexual maturity , mating , selection (genetic algorithm) , orthoptera , ecology , zoology , stabilizing selection , trade off , evolutionary biology , larva , genetic variation , genetics , gene , computer science , artificial intelligence
We measured in the field the intensity and mode (i.e., directional, stabilizing) of sexual selection acting jointly on body size and time of sexual maturity in the univoltine, polygamous grasshopper Sphenarium purpurascens . Statistical analyses indicated that selection favored large and protandrous males in terms of a higher mating success. At the same time, evidence of correlational selection acting simultaneously on body size and time to sexual maturity was found. Thus, selection should strengthen the relationship between body size and the time of sexual maturity. Theoretical work suggests the existence of a trade‐off between reaching a large size and early sexual maturation in insects. The present study does not support the existence of this kind of trade‐off. Recent theoretical and empirical work like the one reported here suggests that such a trade‐off may not be necessarily expected if growth rates (which are often assumed to be invariable) are affected by environmental and genetic factors.