Evolution of Cuticular Hydrocarbons of Hawaiian Drosophilidae

Abstract

Hawaiian Drosophila offer an excellent model for adaptive evolution. More than 500 species are reported in Hawaiian islands, and there is considerable diversity in behavior and morphology. Such diversity is mainly driven by sexual selection. In this study qualitative and quantitative chemical compositions of cuticular hydrocarbons (CHCs) in 138 flies belonging to 27 Hawaiian Drosophila species, picture-winged and non picture-winged, were analyzed regarding sexual dimorphism, differences in saturation, branching position, and lengths of CHCs. We found significant variation in the CHC patterns. In several subgroups, new species show decreases in unsaturated hydrocarbons, and gradual increases in branched compounds, monomethylalkanes and dimethylalkanes, not commonly found in Drosophila. Moreover, branching positions gradually shifted towards internal carbons, and chain lengths increased in the new species. The long-term evolution of CHCs in the light of the recent evolutionary migration and adaptation history of Hawaiian Drosophila species along the developing archipelago was discussed.

Phylogenetics of the Antopocerus-Modified Tarsus Clade of Hawaiian Drosophila: Diversification across the Hawaiian Islands

“…This is evidenced by the diversity of morphologies [28]–[31], behaviors [32], [34]–[37] and chemical signaling [82] that are associated with sexual selection and described in species of the AMC. Geographic isolation followed by a random and slight change in the way these secondary sexual characters are used could cause pre-mating isolation when sister species of Hawaiian Drosophila came back into contact with each other [83], [84] and secondary sexual characters have been shown to be important in mate choice [43].…”

“…The males of many AMC will vibrate and semaphore their wings in species distinctive patterns in the vicinity of conspecific females [32], [34]. Courtship song and cuticular hydrocarbons are diverse and stereotypical to species in the Hawaiian Drosophila and are likely used in identifying conspecific mates in the AMC [82], [85]–[87]. In at least the antopocerus group there are sophisticated structures for sensing these traits [88].…”

Hydrocarbon divergence and reproductive isolation in Timema stick insects

“…For example, in Chorthippus parallelus grasshoppers, male hydrocarbon variation, but not other potential mate-choice signals, was significantly linked with the degree of assortative mating among individuals from 12 populations [48]. Similarly, in Chrysochus beetles [49], and some Drosophila vinegar flies (e. g., [50,51]), mating between individuals from closely-related species or strains is affected in part by variation in cuticular hydrocarbon profiles. In Timema , assuming individuals indeed detect aspects of hydrocarbon profiles, decreased propensity to accept mates with lower hydrocarbon profile similarity would limit the likelihood of potentially costly interspecific matings.…”

Insect pheromones: An overview of function, form, and discovery

“…In the same year, 86 Adolf Butenandt, a German biochemist who was awarded the 87 Nobel Prize in Chemistry in 1939 (for the chemical synthesis of 88 sex hormones), identified the first pheromone chemically [8]. 89 Since then, numerous advances have been made in our under- 90 standing of the functional properties of pheromones. 91 2.1.…”

“…297 Natural enemies can eavesdrop on alarm pheromones of other 298 species in order to find prey. Lady beetles [77], hover flies [78], par-299 asitic wasps [79], and Carabidae ground beetles [80] epoxides, or ketones [89], incorporation of branched fatty acids or 332 amino acids [90], or a change in stereochemistry [86,91]. In order 333 for chemical communication to be effective, the signal needs to 334 be detected amidst substantial chemical noise.…”