Contrasting population genetic structure of two widespread aquatic insects in the Chilean high-slope rivers

Abstract

Dispersal and many other factors affect population genetic structure. In central Chile, rivers are characterised by strong currents and transverse mountain chains, which impose physical barriers to the populations that inhabit them. The objective of the present study was to study the population genetic structure of two widespread species of aquatic insects, the caddisfly Smicridea annulicornis and the mayfly Andesiops torrens, in three isolated rivers, Choapa, Maipo and Maule. The analysis of population structure, using both mtDNA (cytochrome C oxidase subunit 1, COI) and nuclear markers (amplified fragment length polymorphism, AFLP), considered samples from within and among rivers. In S. annulicornis, we found differentiation within and among rivers, indicating a low dispersal among the study area. Populations of A. torrens shared haplotypes in all three rivers and no differences were found among rivers, indicating that this species probably has more dispersal potential than does S. annulicornis; however, significant differences were observed within rivers. Our results indicate that the transverse mountain chains are not a barrier for A. torrens, which can disperse among rivers. Within rivers, the population structure suggests that these species are probably adapted to avoid drift because of the torrential character of these Chilean rivers.

Local population genetic structure of the montane caddisfly Drusus discolor is driven by overland dispersal and spatial scaling

“…Sabando et al . (), on the other hand, observed low dispersal rates and low connectivity between sites for one caddisfly species in South America, suggesting that patterns are likely to be species specific. This is not surprising considering different morphological constitutions and life‐history traits relevant for dispersal (e.g.…”

“…Previous population genetic studies of headwater insect species have mainly used DNA sequencing and AFLPs to assess regional patterns and revealed strong catchment differentiation (e.g. Hughes et al ., ; Wishart & Hughes, ; Lehrian et al ., ; Yaegashi et al ., ), strong differentiation within catchments (Monaghan et al ., ) or variation among codistributed taxa (Monaghan et al ., ; Sabando et al ., ). A few examples also show effective dispersal with limited population structure (e.g.…”

Effects of wind‐driven spatial structure and environmental heterogeneity on high‐altitude wetland macroinvertebrate assemblages with contrasting dispersal modes

“…In contrast, flying species might overcome geographical barriers more readily (Townsend et al ., ). The ability of some flying taxa (mayflies) to disperse between river basins is supported by population genetic data from a study in north‐central Chile spanning one of the basins included here (Sabando et al ., ). In our study, the importance of flight in structuring the flying assemblage is suggested by the fact that the majority of the taxa with spatially structured abundance preferentially dispersed via active flight (Verdugo, ), and their greater dispersal aptitude is substantiated by the broad‐scale spatial pattern that we detected for this group.…”

Methodological framework for projecting the potential loss of intraspecific genetic diversity due to global climate change

“…Partly, however, the different resolution might also be explained by the different biology as well: the low dispersal capacity of land snails usually leads to stronger population differentiation than can be generally expected from flying insects. However, studies of winged aquatic insects have shown species-specific patterns of genetic population structure and population differentiation that suggest dispersal capacity varies dramatically even among ecological similar or closely related species [28,69,70], which is also true for land snails e.g. [71].…”

“…However, the large geographic overlap and co-occurrence of only slightly disjunct clades at the same sites argues against a deeper biological significance of the inference clade level. In other species of Smicridea population structure and population differentiation are more pronounced, even at smaller geographic scales [42,70]. In Trochulus , highly divergent and reproductively isolated lineages may be restricted to single valleys [36,72,73].…”