Habitat heterogeneity and intraguild interactions modify distribution and injury rates in two coexisting genera of damselflies

Summary Sublethal effects of predation can affect both population and community structure. Despite this, little is known about how the frequency of injury varies in relation to habitat, aquatic community characteristics or between trophically similar, coexisting taxa. In a tidal freshwater ecosystem, we first examined injuries (lamellar autotomy) of E nallagma and I schnura damselfly larvae, which have unique behaviours and susceptibilities to predation, as a function of habitat type, body size and overall odonate density. We also examined relative abundance of these genera and potential anisopteran predators as a function of habitat type. The frequency of injury to E nallagma was high when larvae were small and overall odonate density was high. For I schnura, however, the frequency of injury depended on habitat and was high for small larvae in less disturbed habitats low on the shore. I schnura were most frequently found in more disturbed habitats high on the shore, whereas E nallagma were more frequently found in less disturbed habitats low on the shore. The relative importance of factors hypothesised to structure odonate communities varied between coexisting E nallagma and I schnura . Distinctive distributions and patterns of injury for each genus provided new insights on the potential for intraguild interactions to modify habitat associations in tidal freshwater ecosystems.