Abdominal Pigmentation Variation in Drosophila Polymorpha: Geographic Variation in the Trait, and Underlying Phylogeography

Abstract

Abstract. Drosophila polymorpha is a widespread species that exhibits abdominal pigmentation variation throughout its range. To gain insight into this variation we combined phenotypic and genotypic data to test a series of nested hypotheses. First, we tested the null hypothesis that geographic variation in pigmentation is due to neutral factors. We used nested clade analysis to examine the distribution of haplotypes from a nuclear and a mitochrondrial locus. Restricted gene flow via isolation by distance, the primary inference of this phylogeographic analysis, was then used to generate and test the hypothesis of increasing average abdominal pigmentation difference with increasing geographic distance. We found no correlation between geographic distance and phenotypic distance. We then tested the hypothesis that pigmentation is affected by environmental differences among localities. We found a significant effect of habitat type on the average abdominal pigmentation phenotype of different localities. Finally, we tested the hypothesis that pigmentation in D. polymorpha is associated with desiccation resistance. We found that dark individuals of both sexes survived significantly longer in a desiccating environment than light individuals. These patterns combined lead us to hypothesize that abdominal pigmentation variation in D. polymorpha is important in mediating the organism's interactions with local ecological factors. Color polymorphisms have been of long-standing interest in evolutionary biology due to their visual accessibility and their utility as a trait amenable to genetic dissection (Dobzhansky

Trade-Offs between Predation Risk and Growth Benefits in the Copepod Eurytemora affinis with Contrasting Pigmentation

“…Although, mitochondrial polymorphisms have been found to be linked with pigmentation patterns in various species (e.g., cladocerans [24], shrimps [25], insects [58], fish [59]), there was no association between pigmentation and mtDNA genotypes in the Baltic Eurytemora affinis . This does not, however, imply an absence of genetic differences between the copepods with different pigmentation phenotypes, both with regard to genes responsible for positioning pigments in space and time and those responsible for synthesis of pigments.…”

Mechanism of Silver Nanoparticles Action on Insect Pigmentation Reveals Intervention of Copper Homeostasis

“…For this reason, no demelanization has resulted when mature adult flies are exposed to AgNPs because pigment granules are already fixed in their cuticle through sclerotization. Cuticular pigmentation is an essential process in insect life because of its involvement with variety of diverse functions, which includes immunity, life span, and physiological and behavioral manifestations such as desiccation resistance [45] swarming, feeding, social dominance, mate preference and courtship display [46]. Therefore, the demelanization effect noticed in laboratory Drosophila at nontoxic concentration points to a situation where insect populations in the wild could be altered in a significant way if exposed to AgNPs.…”

Combining Phylogeography with Distribution Modeling: Multiple Pleistocene Range Expansions in a Parthenogenetic Gecko from the Australian Arid Zone

“…In addition, combination of phylogeographic approaches with analyses of ecological tolerances and interactions can permit cross-validation of phylogeographic inferences [20] and lead to considerably more insight into the underlying processes that generate the observed patterns of geographic distributions, amounts and distributions of genetic variation, and ecological and climatic correlates [e.g. 21], [22], [23].…”