The effects of preservatives on the regurgitation of gut contents by Chironomidae (Diptera) larvae

Abstract

The commonly used preservatives for chironomid larvae were found to cause regurgitation of the gut contents, the incidence of regurgitation being higher when the gut in at least two of the thoracic segments was full. The Tanypodinae larvae regurgitated more frequently than others, because of differences in their gut morphology, the nature of the food ingested, or a combination of both. Handling of the larvae also caused regurgitation. Increased predation by Tanypodinae larvae appeared if there was a delay between collection and preservation or examination of the samples. These problems can be overcome by rapidly freezing the samples immediately in either powdered solid carbon dioxide or liquid air.