Streamlining techniques for rearing large quantities of the damselfly, Ischnura ramburii (Odonata: Coenagrionidae) in the laboratory

Background/Question/Methods

Dragonflies and damselflies often served as model organisms for answering a range of ecological and evolutionary questions.  Although aquatic naiads and terrestrial adults can be readily collected in the field, laboratory rearing permits researchers to regulate variables during development that are difficult to control in the field.  In addition, many laboratory-based experimental designs typically require large sample sizes of genetically-related organisms at the same developmental stage.  Several rearing methods have been published for Odonata, but they recommend methods that become laborious when rearing large quantities simultaneously.  We reared large numbers (1,000+) of the coenagrionid damselfly, Ischnura ramburii, from field-collected adults (N=8) that were mated in the lab through emergence of their offspring while streamlining some previously published recommendations.  We also estimated the duration of naiad survivorship in the lab without food by starving a subset of naiads (N=170).

Results/Conclusions

Of the eight mated females, 157± 33.9 naiads female^-1 were produced.  66.4% of the naiads successfully emerged as adults with males and females emerging a median of 75 and 77 days, respectively, after hatching.  Much naiad mortality (23%) occurred during emergence when they failed to locate emergence substrates and drowned.  Naiads survived a mean of 14.2 days without food, demonstrating that naiads can be maintained in the lab with infrequent feedings.  We found that several previously published rearing recommendations for small damselfly cultures can be modified to improve rearing efficiency.   Culturing large quantities of damselfly in the lab is manageable and broadens the experimental designs of many diverse research avenues.