Morphometric variation in chromosomally polymorphic grasshoppers (Orthoptera: Acrididae) from South America: Bergmann and converse Bergmann patterns

COLOMBO, P.C.; REMIS, MARIA ISABEL

FLORIDA ENTOMOLOGIST

FLORIDA ENTOMOLOGICAL SOC

Lugar: Nueva York; Año: 2015 vol. 98 p. 570 - 574

0015-4040

Leptysma argentina Bruner, Trimerotropis pallidennis (Burmeister), and Cornops aquaticum Bruner are South-American grasshoppers (Orthoptera:Acrididae) whose chromosome polymorphisms were intensively studied. Leptysma argentina lives in central-east Argentina andin Uruguay and was polymorphic for a centric fusion whose presence is significantly correlated with a larger body size; this parameter wasshown to be associated with sexual selection and longevity selection; this species exhibited a marked latitudinal Bergmann pattern. In contrast,Trimerotropis pallidipennis followed a converse altitudinal Bergmann cline; males from higher altitudes were significantly smaller. Thisspecies supported an extended polymorphism for several inversions, which are correlated intrapopulationally with larger body size. Finally,C. aquaticum showed an evident example of Bergmann?s rule for tegmen length; this species was polymorphic for 3 centric fusions, whosefrequency increased southward, as in L. argentina. One of the fusions was associated with increased body size. We noticed that in all casesthe rearrangement that was related to body size increased in the direction in which this variable was adaptive, thus suggesting a possibleinvolvement of chromosome polymorphism in body size selection.