Physiological effects of heat stress on Hawaiian picture-wingDrosophila: genome-wide expression patterns and stress-related traits

Abstract

Two Hawaiian picture-wing Drosophila differ in their temperature tolerances with the ecologically rare species, D. silvestris, showing reduced survival, reduced sperm mobility and greater gene expression changes at high temperatures compared to the common D. sproati. Thus the rare species may have reduced capacity to adapt to future climate changes.

Hawaiian picture‐winged Drosophila exhibit adaptive population divergence along a narrow climatic gradient on Hawaii Island

“…HSPs and their cognates are part of the protein quality system that assists in degradation of denatured or aggregated proteins and is mounted when organisms are exposed to environmental stressors, including oxidative, physical activity, heavy metals, and temperature (Sørensen, Kristensen, & Loeschcke, ). We found that genes HSP23 and HSP83 were differentially expressed in low‐and high‐elevation D. sproati populations, and heat‐shocked D. sproati (Uy et al, ) , D. silvestris (Uy et al, ), and D. melanogaster (Leemans et al, ; Sørensen et al, ). Also notable were two DEGs belonging to the HSP70 superfamily that showed differential expression in heat‐shocked D. melanogaster: HSC70–3 (Leemans et al, ) and HSC70Cb (Sørensen et al, ).…”

“…These include 13.5% of the 74 heat‐shock‐inducible genes in identified by Leemans et al, and 15.6% of the 199 heat‐responsive genes identified by Sørensen et al, , both in D. melanogaster . Our data set also includes 20.1% of 106 DEGs identified within D. sproati subjected to a one‐hour treatment at 25 ° C, as compared to those at a controlled temperature of 16 ° C, and 18.3% of 246 DEGs found in D. silvestris after the same one‐hour, 25 ° C treatment (Table , Uy et al, ). That certain genes were differentially expressed across multiple Drosophila temperature treatment studies and between our low‐ and high‐elevation population groups suggests these genes have important roles in adaptation to thermal conditions.…”

“…This natural combination of isolating forces, diverse habitat, and variable biotic communities, which together encourage population differentiation and local adaptation, is thought to account for the large number of adaptive radiations and endemic species found within the archipelago (Gillespie & Roderick, 2002;Price & Clague 2002). These native species and ecosystems may be particularly vulnerable to global climate change due to the relatively small natural habitat patches and population sizes, negative impacts from invasive species, and dramatic habitat degradation, fragmentation, and loss (Hobbelen, Samuel, Foote, Tango, & LaPointe, 2013;Uy, LeDuc, Ganote, & Price, 2015). As evidence of this, numerous recent extinctions have occurred, and many of the remaining native species are increasingly confined to small preserves or found only at higher elevations (Benning, LaPointe, Atkinson, & Vitousek, 2002;Howarth & Gagné, 2012).…”

“…Understanding how species respond to climate change is a pertinent theoretical question and an immediate conservation priority (Hoffmann & Sgrò 2011;Kellermann et al, 2009;Porcelli, Gaston, Butlin, & Snook, 2017). A recent study of two Hawaii Island endemic picture-winged Drosophila, the rare D. silvestris and the more ubiquitous D. sproati, found strong species-level differences in temperature tolerance (Uy et al, 2015), and previously observed clinal patterns of genetic differentiation in D. silvestris (Craddock & Carson 1989) suggest that temperature may also be driving adaptive population divergence. This current study continues such investigations of D. sproati by testing for adaptive divergence between the highest and lowest elevation populations within a fragmented portion of wet forest habitat on the east side of Hawaii Island.…”

Hybrid sterility and evolution in Hawaiian Drosophila: differential gene and allele-specific expression analysis of backcross males

“…All parental, F 1 and BC populations were maintained in a controlledenvironment room maintained at a constant 18°C, 70% relative humidity with a 12:12 light/dark cycle. This is a standard environment for rearing Hawaiian Drosophila (Uy et al, 2015) with a generation time of ∼ 3-4 months. Adults were housed in 4-l glass jars with a damp fine sand floor and containing 3 to 5 vials of adult food.…”