Chromosomal polymorphism, morphological traits and male mating success in Leptysma argentina (Orthoptera)

Abstract

Leptysma argentina (Acrididae: Orthoptera) is polymorphic for a centric fusion between pairs 3 and 6 of its basic chromosomal complement. With the aim of carrying out an analysis of selection components in this species, male mating success, in relation to karyotype and three morphometric traits, was assessed by using experimental contests with four males and one female per mating cage. Karyotype was assessed in terms of fused chromosome 3/6 dosage and coded as "0", "1" and "2" for unfused homozygotes, heterozygotes and fusion homozygotes, respectively. The individual ANOVA showed significant differences between "successful" and "unsuccessful" males in all four measured characters. Fusion carriers showed a higher relative fitness. Since the phenotypic correlations among traits were significant, the selective effects were assessed by means of a multivariate analysis, which demonstrated that selection acted significantly on femur length only, selection on karyotype being indirect. Given that the fusion frequency has been constant since 1985, the presence of selective trade-offs cannot be ruled out.

Micro-Evolution in Grasshoppers Mediated by Polymorphic Robertsonian Translocations

“…Body size-related traits also seem to be the reason for the effect of fusion 3/6 on other selection components. Mating success in L. argentina was increased in males (Colombo et al 2001) and females (Colombo et al 2004) correlated with an increase in femur length associated to this fusion.…”

Molecular and morphometric variation in chromosomally differentiated populations of the grasshopper Sinipta dalmani (Orthopthera: Acrididae)

“…Many examples in insects have pointed out relationships among morphometric traits and different fitness components such as fertility, fecundity, and viability (Taylor and Kekic 1988;Santos et al 1988;Hasson et al 1993;Perfectti et al 2000;Remis et al 2000;Remis 2002: Colombo et al 2001Pensel and Remis 2007). Moreover, some chromosomal rearrangements are associated with effects on morphometric traits, establishing additional variation on which selection may be acting (White and Andrew 1960;White et al 1963;Butlin et al 1982;Hasson et al 1992;Remis et al 2000;Colombo et al 2001;Werle and Klekowaki 2004). In natural populations of S. dalmani, we detected significant phenotypic variation related to the M 4 inversion polymorphism.…”

Karyotype Plasticity in Crickets: Numerical, Morphological, and Nucleolar Organizer Region Distribution Pattern ofAnurogryllussp.

“…Moreover, supernumerary chromosomes and extra chromosomal segments have also been registered in orthopteran species (Hewitt 1979; Henriques-Gil et al 1984; López-Fernández et al 1984; Bhunya and Das 1985; Lamborot and Alvarez-Sarret 1985; Davenport 1986; Colombo 1987; Das 1989; Fossey et al 1989; Das and Das 1991; Mirol and Bidau 1991; Warchalowska-Sliwa et al 1992; Eugênio and Cella 1996; Zefa 1999; Colombo et al 2004). The mechanisms responsible for the chromosomal changes observed in orthopteran could have particular effects on karyotype evolution, taking into account that these could influence the frequency of recombination, fertility, and mating success (Hewitt 1979; López-Fernández et al 1984; Colombo 1987, 1993a, 1993b; Fossey et al 1989; Colombo et al 2001, 2004). …”