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Mobility is related to species traits in noctuid moths


Per-Eric Betzholtz, School of Natural Sciences, Linnaeus University, SE-39182 Kalmar, Sweden.


1. Mobility is important for the understanding of how species survive in fragmented landscapes and cope with increasing rates of habitat and climate change. However, mobility is a difficult trait to explore and is poorly known in most taxa. Species traits have been studied in relation to range shifts, extinction risks, and responses to habitat area and isolation, and have also been suggested as good estimators of mobility. Here we explore the relation between mobility and species traits in noctuid moths.

2. We sampled noctuid moths by an automatic light-trap on an island far out in the Baltic Sea. We compared traits of the non-resident species on the island with traits of a species pool of assumed potential migrants from the Swedish mainland.

3. Mobility was significantly related to adult activity period, length of flight period, and the interaction between host-plant specificity and distribution area. Widely distributed host-plant generalists were more mobile than host-plant specialists with more restricted distribution, and species with an adult activity period in August to September moved to the island to a higher extent than species with an adult activity period in May to July. Our results remained qualitatively robust in additional analyses, after controlling for phylogeny and including all species recorded on the island, except for the trait ‘length of flight period’.

4. Our results highlight the importance of the relation between mobility and species traits. Noctuid moths with certain traits move over longer distances than earlier known. This finding is important to include when predicting range dynamics in fragmented and changing landscapes, and when conservation measures of species are devised.