Molecular and quantitative genetic differentiation across Europe in yellow dung flies

Abstract

Relating geographic variation in quantitative traits to underlying population structure is crucial for understanding processes driving population differentiation, isolation and ultimately speciation. Our study represents a comprehensive population genetic survey of the yellow dung fly Scathophaga stercoraria, an important model organism for evolutionary and ecological studies, over a broad geographic scale across Europe (10 populations from the Swiss Alps to Iceland). We simultaneously assessed differentiation in five quantitative traits (body size, development time, growth rate, proportion of diapausing individuals and duration of diapause), to compare differentiation in neutral marker loci (FST) to that of quantitative traits (QST). Despite long distances and uninhabitable areas between sampled populations, population structuring was very low but significant (FST = 0.007, 13 microsatellite markers; FST = 0.012, three allozyme markers; FST = 0.007, markers combined). However, only two populations (Iceland and Sweden) showed significant allelic differentiation to all other populations. We estimated high levels of gene flow [effective number of migrants (Nm) = 6.2], there was no isolation by distance, and no indication of past genetic bottlenecks (i.e. founder events) and associated loss of genetic diversity in any northern or island population. In contrast to the low population structure, quantitative traits were strongly genetically differentiated among populations, following latitudinal clines, suggesting that selection is responsible for life history differentiation in yellow dung flies across Europe.

Population genetic structure of serotine bats (Eptesicus serotinus) across Europe and implications for the potential spread of bat rabies (European bat lyssavirus EBLV-1)

“…Similar findings have been reported in other taxa (Demont et al 2008) and suggest genetic homogenisation over a large geographical scale and possibly high gene flow across the continent. Lack of information on the species' mating system and movements restricts our understanding of the mechanisms driving this gene flow.…”

Diapause termination of Rhagoletis cerasi pupae is regulated by local adaptation and phenotypic plasticity: escape in time through bet‐hedging strategies

“…Adults from K. Nera are known to emerge earlier than those from Dafni in local field conditions, and reciprocal transplant experiments (between these two populations in field) revealed a genetic basis to geographical variation of diapause intensity (Papanastasiou et al ., ), implying that the above populations are not ecologically exchangeable, despite the presence of gene flow (Rader et al ., ). Thus, the existence of local adaptation in the timing of diapause termination of R. cerasi pupae, even under conditions of ongoing gene flow, is in agreement with recent related studies regarding to the yellow dung fly and Drosophila montana (Demont et al ., ; Tyukmaeva et al ., ). Nevertheless, conditions experienced mostly by egg and larvae in the field before being brought back to the laboratory for collecting pupae remain uncontrolled (the initial rearing environment cannot be controlled in R. cerasi s because of lack of efficient rearing methodology; Köppler et al ., ) and might add some variability in diapause responses.…”

EB Ford revisited: assessing the long-term stability of wing-spot patterns and population genetic structure of the meadow brown butterfly on the Isles of Scilly

“…Given the small geographical distances among the islands of the Scilly archipelago, the discovery of population structure in an insect capable of flying short distances is remarkable, especially given that previous studies of other flying insects have found comparatively weaker population structure over much larger geographic scales (Demont et al , 2008). Our results also contrast somewhat with those of a previous study of M. jurtina that found relatively weak population structure across southern England, although in this particular case F st was estimated from allozymes that tend to have lower levels of variability than AFLPs (Goulson, 1993).…”