Clinal patterns of desiccation and starvation resistance in ancestral and invading populations of Drosophila subobscura

Abstract

As invading species expand, they eventually encounter physical and biotic stressors that limit their spread. We examine latitudinal and climatic variation in physiological tolerance in one native and two invading populations of Drosophila subobscura. These flies are native to the Palearctic region, but invaded both South and North America around 1980 and spread rapidly across 15° of latitude on each continent. Invading flies rapidly evolved latitudinal clines in chromosome inversion frequencies and in wing size that parallel those of native populations in the Old World. Here we investigate whether flies on all three continents have evolved parallel clines in desiccation and starvation tolerance, such that flies in low-latitude regions (hot, dry) might have increased stress resistance. Starvation tolerance does not vary with latitude or climate on any continent. In contrast, desiccation tolerance varies clinally with latitude on all three continents, although not in parallel. In North American and Europe, desiccation tolerance is inversely related to latitude, as expected. But in South America, desiccation tolerance increases with latitude and is greatest in relatively cool and wet areas. Differences among continents in latitudinal patterns of interspecific-competition potentially influence clinal selection for physiological resistance, but no simple pattern is evident on these continents.

Local adaptations of life‐history traits of a Drosophila parasitoid, Leptopilina boulardi: does climate drive evolution?

“…To our knowledge, no evidence of a direct effect of humidity on selection of life-history traits has been shown except for desiccation resistance (Karan et al, 1998;Gilchrist et al, 2008), but patterns for this trait are not really clear. Other studies on humidity-dependent selection are needed to understand if this climatic factor directly affects life-history traits other than desiccation resistance.…”

“…Desiccation resistance is the only life-history trait that has been considered as a result of differences in humidity (Karan et al, 1998;Gilchrist et al, 2008) but other traits may be under selection of humidity and precipitation, such as timing of egg-laying. Desiccation resistance is the only life-history trait that has been considered as a result of differences in humidity (Karan et al, 1998;Gilchrist et al, 2008) but other traits may be under selection of humidity and precipitation, such as timing of egg-laying.…”

Physiological climatic limits inDrosophila: patterns and implications

“…This species originates in Europe where it is adapted to cool conditions and its activity is curtailed in warm and dry conditions (Huey and Pascual, 2009). Following invasion, clines along climatic gradients developed for traits and genetic polymorphisms; several clines are consistent with those found in Europe but other patterns are more complex, as in the case of desiccation resistance, which shows a consistent increase in resistance with latitude in Europe and North America but the opposite pattern in South America (Gilchrist et al, 2008). The climatic regions and latitudinal ranges occupied by this species in North and South America are similar to those found in Europe (Prevosti et al, 1988), suggesting that the invasive range of D. subobscura is limited by climatic variables similar to those in its native range irrespective of any changes in clinal patterns.…”

Measuring thermal behavior in smaller insects: A case study in Drosophila melanogaster demonstrates effects of sex, geographic origin, and rearing temperature on adult behavior

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16] Many of these clines reflect evolutionary adaptive differentiation in response to different climates, while others reflect simple to complex aspects of demography. [17][18][19][20][21][22] The mechanistic basis of many clines remains elusive, and a major emphasis in the dissection of clines has been to understand how the observed variation in fitness-associated traits reflects the adaptive response to specific environmental conditions. 23,24 A key component in the potential adaptation to climatic variation is the behavioral response to temperature and temperature variation experienced in natural habitats, which may have pronounced effects on organismal performance and fitness.…”