North–south differences in circadian eclosion rhythm in European populations of Drosophila subobscura

Abstract

The circadian pupal eclosion rhythm was studied in 12 strains of Drosophila subobscura originating from two regions: Scandinavia (56-63°N), and the Canary Islands (28°N). Inmost parameters of the rhythm, ample variability was found both within and between the regions. Among the strains the phase of the eclosion median in an entraining die! light-dark cyc!e varied by 8.1 h, and the period of the free-running rhythm (r) by 2.2 h. In the comparison between the two regions, the Scandinavian entrained rhythm had on average a 2.8 h ear!ier phase, r was 0.9 h shorter, and the amplitude of the rhythm was lower. Of the rhythm parameters, early phase was correlated with short r (r = 0.76), and the amplitude of the entrained rhythm was correlated with the amplitude of the free-running rhythm (r =0.98). In addition to the geographica! variation, a putative arhythmic recessive autosomal mutant was found to segregate in one Scandinavian strain. The lack of photoperiodic adult diapause was confirmed in D. subobscura. The results show that the circadian eclosion rhythm in a nonphotoperiodic species can vary latitudinally in a fashion simi!ar to that of photoperiodic species.

Genome-wide evolutionary response to a heat wave in Drosophila

“…Furthermore, some reported evolutionary responses to climate change can be better explained as adaptive shifts in the timing of seasonal events rather than as a direct effect of increasing temperature [21]. A wide variety of temperate animals and plants use photoperiodic cues to time their seasonal activities [22], but D. subobscura seems to be idiosyncratic in this regard because it combines a short generation time with an absence of strong photoperiodism [23] and an ecological generalism [24]. The marked seasonal cycling of its inversion polymorphism is not restricted to one chromosome but happens genome-wide at various localities, and the pattern of this cycling neatly matches the seasonal variation in ambient temperature ( figure 2a,b).…”

Effect of Different Light Regimes on Pre-Adult Fitness in Drosophila melanogaster Populations Reared in Constant Light for over Six Hundred Generations

“…There is some evidence for the adaptive significance of circadian rhythms under field conditions from studies on clinal variation in circadian parameters, such as τ, of the eclosion (Lankinen, 1986;Lankinen, 1993) and oviposition rhythms of various species of Drosophila (Allemand & David, 1976). However, the observation of clinal variation in τ from natural populations cannot address the issue of the possible intrinsic adaptive value of circadian rhythms.…”

Latitudinal clines: an evolutionary view on biological rhythms,

“…In animals, nearly all latitudinal studies deal with Drosophila ( figure 3b-d [24] from the Canarian Islands (288 N) into Scandinavia (628 N). Two further studies deal with the eclosion rhythm of Drosophila auraria from Japan [26,45], but these cover only an 88 latitude range ( figure 3c,d).…”

“…Selection pressure on timing for photoperiodic diapause induction is also evident in studies on (a) Brown, Sericinus montelus ( pupae) [13]; black, Wyeomyia smithii (larvae) [14]; purple, Bruchidius dorsalis (larvae) [15]; pink, Chrysopa carnea (adult) [16]; turquoise, Homoeosoma electellum (larvae) [17]; khaki, Tetranychus pueraricola (adult) [18]; cyan, Orius sauteri (adult) [19]; dark blue, Acronicta rumicis (larvae) [11]; red, Nasonia vitripennis (larvae; maternally induced) [20]; green, Drosophila montana (adult) [21]; grey, D. phalerata (adult) [22]; blue, D. transversa (adult) [22]. [23]; blue, D. subobscura (eclosion) [24]; red, D. littoralis (eclosion) [25]; green, D. auraria (eclosion) [26]. Three equatorial regression data points from Allemand & David [23] were not plotted in (b) for axis consistency.…”