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Abstract Environmental adaptation and species divergence often involve suites of co‐evolving traits. Pigmentation in insects presents a variable, adaptive, and well‐characterized class of phenotypes for which correlations with multiple other traits have been demonstrated. InDrosophila, the pigmentation genesebonyandtanhave pleiotropic effects on flies' response to light, creating the potential for correlated evolution of pigmentation and vision. Here, we investigate differences in light preference within and between two sister species,Drosophila americanaandD. novamexicana, which differ in pigmentation in part because of evolution atebonyandtanand occupy environments that differ in many variables including solar radiation. We hypothesized that lighter pigmentation would be correlated with a greater preference for environmental light and tested this hypothesis using a habitat choice experiment. In a first set of experiments, using males ofD. novamexicanaline N14 andD. americanaline A00, the light‐bodiedD. novamexicanawas found slightly but significantly more often thanD. americanain the light habitat. A second experiment, which included additional lines and females as well as males, failed to find any significant difference betweenD. novamexicana‐N14 andD. americana‐A00. Additionally, the other dark line ofD. americana(A04) was found in the light habitat more often than the light‐bodiedD. novamexicana‐N14, in contrast to our predictions. However, the lightest line ofD. americana, A01, was found substantially and significantly more often in the light habitat than the two darker lines ofD. americana, thus providing partial support for our hypothesis. Finally, across all four lines, females were found more often in the light habitat than their more darkly pigmented male counterparts. Additional replication is needed to corroborate these findings and evaluate conflicting results, with the consistent effect of sex within and between species providing an especially intriguing avenue for further research.
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Telomere‐Specialized Retroelements in Drosophila : Adaptive Symbionts of the Genome, Neutral, or in Conflict?
Abstract Linear chromosomes shorten in every round of replication. InDrosophila, telomere‐specialized long interspersed retrotransposable elements (LINEs) belonging to the jockey clade offset this shortening by forming head‐to‐tail arrays atDrosophilatelomere ends. As such, these telomeric LINEs have been considered adaptive symbionts of the genome, protecting it from premature decay, particularly asDrosophilalacks a conventional telomerase holoenzyme. However, as reviewed here, recent work reveals a high degree of variation and turnover in the telomere‐specialized LINE lineages acrossDrosophila. There appears to be no absolute requirement for LINE activity to maintain telomeres in flies, hence the suggestion that the telomere‐specialized LINEs may instead be neutral or in conflict with the host, rather than adaptive.
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- Award ID(s):
- 1818017
- PAR ID:
- 10460044
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- BioEssays
- Volume:
- 42
- Issue:
- 1
- ISSN:
- 0265-9247
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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