Research objectives and content
The water spider, the only entirely aquatic spider, receives legal protection throughout much of its range. Although locally abundant, it is often absent from apparently suitable freshwater habitats.
Ecophysiological limitations on dispersal and colonization between patchy habitats suggest that populations may experience limited genetic exchange: consequently, environmental destruction and increasing habitat isolation potentially threaten this species. Using Danish populations, this project aims to examine the degree of genetic isolation, and the mechanisms of, and limitations on, dispersal. The population genetic structure and levels of gene flow between ponds at varying distances from each other will be assessed using allozymes and mtDNA sequencing. Environmental and ecophysiological factors limiting distribution will be evaluated by ecological and limnological characterization of ponds with and without spiders, studying the effects on behaviour and physiology of varying hydrological conditions, and by translocation experiments to establish whether dispersal could be limiting exploitation of empty niches. The mechanisms of, and physiological constraints on, dispersal will be examined by trapping, and measuring the tendency to balloon, rates of water-loss, and cuticular differences between different instars in the laboratory.
Training content (objective, benefit and expected impact)
The training gained in ecology, genetics, physiology, and arachnology will provide a strong foundation for future work at the interface of these important areas in terms of biodiversity and conservation. The water spider provides a model system. The results will be relevant to management decisions across Europe affecting this species, and others, with limited dispersal in a changing and increasingly fragmented environment. Links with industry / industrial relevance (22)