Unique phenotypes and variation in the sex comb patterns and their evolutionary implications in the Drosophila bipectinata species complex (Diptera: Drosophilidae)

Abstract

Abstract. Understanding the genetic mechanisms of morphological evolution is one of the greatest challenges in evolutionary biology and for such studies sexually dimorphic traits in closely related species are of prime interest. In the Drosophila bipectinata species complex, which consists of four closely related species, namely D. bipectinata, D. parabipectinata, D. malerkotliana and D. pseudoananassae, the pattern of sex combs (a sexually dimorphic trait) is found to be highly diversified. The present investigation documents some unique and new sex comb phenotypes and demarcates intra-and interspecific variations in the sex comb pattern among the four species and their hybrids. There is remarkable similarity in sex comb pattern of D. bipectinata and D. parabipectinata but it differs from that of D. malerkotliana and D. pseudoananassae, which is in consistent with the phylogenetic relationships among the four species traced out by cytological, biochemical and molecular studies. The genetic basis of inheritance of sex comb patterns, its plausible implication with biogeographical distribution of species and the relationship between degree of hybridization and phylogenetic proximity have been addressed.

Microscale Laser Surgery Demonstrates the Grasping Function of the Male Sex Combs in Drosophila melanogaster and Drosophila bipectinata

“…Thus, although the origin the sex comb is unclear, and may be linked to natural selection and/ or sexual conflict, there is evidence that the elaboration of the trait beyond its grasping function results from sexual selection. Sexual selection may explain the observed incipient diversification of comb size among geographic populations of D. bipectinata and related species (Crossley & Taylor 1985;Polak et al 2004;Matsuda et al 2005;Mishra & Singh 2006), and it may also have contributed to the rich diversity of sex comb shape and size more broadly within the genus.…”

Legs of deception: disagreement between molecular markers and morphology of long-legged flies (Diptera, Dolichopodidae)

“…1997; Civetta and Singh 1998; Kopp and True 2002). The gain or loss of MSSCs is a fast process [general review: Wiens 2001; sex combs in Drosophilidae (Diptera): Kopp and True 2002; Mishra and Singh 2006; toothed femora in Sepsidae (Diptera): Puniamoorthy et al. 2008], and at least partly driven by the changes in female preferences (Ng and Kopp 2008).…”

Consistent Positive Co-Variation between Fluctuating Asymmetry and Sexual Trait Size: A Challenge to the Developmental Instability-Sexual Selection Hypothesis

“…D. bipectinata is a member of the ananasssae subgroup of the melanogaster species group [32], and is widely distributed in the Australian and Oriental biogeographic zones [32]. The trait under study is the male sex comb, a heritable and condition dependent secondary sexual trait [33][34][35][36] undergoing incipient diversification throughout its geographic range [35,37,38]. The sex comb consists of two major components (referred to as C1 and C2), each comprised of a row stout black bristles, or "teeth", arranged obliquely along the foretarsus of each of the front legs of males ( Figure 1); females do not possess sex combs.…”