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Keywords:

  • Connectivity;
  • landscape;
  • Lepidoptera;
  • metapopulation;
  • multiple resources;
  • resource complementation;
  • spatial aggregation

Abstract. 

  • 1
    Metapopulation theory predicts habitat patch area and isolation to be the main factors affecting the distribution of species dependent of patchily distributed habitats, but the need for multiple resources, which might be spatially separated, is often ignored.
  • 2
    Here, I studied the effect of host plant and nectar flower distributions on the spatial distribution of pupae and adults of two species of burnet moths (Zygaena filipendulae and Zygaena lonicerae), on two spatial scales.
  • 3
    At the landscape scale (10 × 12 km), moths were patchily distributed, but there was no effect of patch isolation on the occurrence of any of the species. On the local scale (2 × 2 km), I expected to find additive effects of the local abundances of larval and adult resources and their abundances in the surrounding areas, but instead, moth abundance decreased with increasing resource connectivity. I interpret this as an aggregation effect, such that at low resource abundances in the area, moths tend to aggregate in patches with higher flower densities.
  • 4
    My results also supported the hypothesis that the spatial distribution of individuals at one life stage is restricted by the requirement of other life stages, because the abundance of pupae of both species were associated with floral resources and abundance of imagos was related to larval resources.
  • 5
    I conclude that in studies aiming at understanding the relative importance of local and regional factors for species distributions, it is important to account for the habitat requirements of all life stages.