Habitat-Specific Morphological Variation among Threespine Sticklebacks (Gasterosteus aculeatus) within a Drainage Basin
نویسندگان
چکیده
Habitat-specific morphological variation, often corresponding to resource specialization, is well documented in freshwater fishes. In this study we used landmark based morphometric analyses to investigate morphological variation among threespine sticklebacks (Gasterosteus aculeatus L.) from four interconnected habitat types within a single lowland drainage basin in eastern England. These included the upper and lower reaches of the river, the estuary, a connected ditch network and a coastal salt marsh. We found significant habitat-specific differences in morphology, with three axes of variation describing differences in orbit diameter, body depth, caudal peduncle shape and pectoral fin positioning as well as variation in relative dorsal and pelvic spine size. Interestingly, the ditch system, an artificial and heavily managed habitat, is populated by sticklebacks with a characteristic morphology, suggesting that human management of habitats can in some circumstances lead to morphological variation among the animals that inhabit them. We discuss the mechanisms that conceivably underlie the observed morphological variation and the further work necessary to identify them. Finally, we consider the implications of habitat-specific body shape variation for the behavioural ecology of this ecologically generalist species.
منابع مشابه
The distribution of divergent mitochondrial DNA lineages of threespine stickleback (Gasterosteus aculeatus) in the northeastern Pacific Basin: post-glacial dispersal and lake accessibility
Aim This study furthers the documentation of the geographical distribution of two divergent (c. 3%) mitochondrial DNA clades in the threespine stickleback (Gasterosteus aculeatus) and tests the hypotheses that the northeastern Pacific distribution has been influenced by post-glacial colonization and lake elevation and that clade identity is associated with certain morphological attributes such ...
متن کاملSpatial phenotypic and genetic structure of threespine stickleback (Gasterosteus aculeatus) in a heterogeneous natural system, Lake Mývatn, Iceland
Eco-evolutionary responses of natural populations to spatial environmental variation strongly depend on the relative strength of environmental differences/natural selection and dispersal/gene flow. In absence of geographic barriers, as often is the case in lake ecosystems, gene flow is expected to constrain adaptive divergence between environments - favoring phenotypic plasticity or high trait ...
متن کاملThe Evolutionary Biology of the Threespine Stickleback
Because the study of variability lies at the heart of evolutionary biology, species that exhibit considerable variation across their geographic range are of special interest to comparative biologists interested in understanding evolutionary patterns and processes at the species level. Few vertebrates match threespine sticklebacks (Gasterosteus aculeatus) in the extent of geographic variation in...
متن کاملLateral line diversity among ecologically divergent threespine stickleback populations.
The lateral line is a mechanoreceptive sensory system that allows fish to sense objects and motion in their local environment. Variation in lateral line morphology may allow fish in different habitats to differentially sense and respond to salient cues. Threespine sticklebacks (Gasterosteus aculeatus) occupy a diverse range of aquatic habitats; we therefore hypothesized that populations within ...
متن کامل