Evaluating the use of coded-wire tags in individually marking Odonata larvae

Abstract

AbstractWe tested a potential new tool for marking Odonata larvae internally, evaluating the retention rates of injected coded-wire tags (CWT) and the effects of these tags on larval performance. Two species of dragonfly larvae (Epitheca canis McLachlan (Odonata: Corduliidae) and Leucorrhinia intacta Hagen (Odonata: Libellulidae)) were injected with CWT. Tag loss rates were assayed over experimental periods of 22 and 60 days, respectively for the two species. To assess whether tagging had negative effects on larvae, mortality, and growth of tagged larvae were compared to untagged larvae held in the same conditions. Tag retention rates were high (92–100%) and CWT were easily retrieved from preserved larvae via dissection, permitting most tagged larvae to be individually identified. There was 100% survival in larvae injected with CWT and tags do not appear to impair growth. The high retention and retrieval rates of this marking approach combined with no increase in mortality associated with tagging suggest that CWT are a useful means of individually labelling a large number of Odonata larvae in a time-efficient manner.