John C. Payne, J. Dunley
Dec 1, 2002
Citations
0
Influential Citations
10
Citations
Journal
Journal of the North American Benthological Society
Abstract
We describe the first use of the element rubidium (Rb) to mark aquatic insects for the study of dispersal. It has been difficult to pursue research that integrates juvenile and adult life stages of aquatic insects. Most species of aquatic insects suffer high mortality during the larval phase; furthermore, larvae shed their entire exoskeletons as they emerge. Adults disperse by flying soon after emergence when they may still be fragile and difficult to handle. We demonstrate that it is possible in both controlled and natural settings to batch-mark very large numbers of aquatic dragonfly (Odonata) larvae by adding Rb as RbCl to the water in which they live. We found that the in-body concentration of Rb in odonate larvae rose to several hundred times the concentration of Rb in the water, and the high concentrations persisted in adults. Less than 1 part per million (by mass) of Rb in water was sufficient to mark odonate larvae. Rb is often used in research on dispersal of terrestrial insects, particularly crop pests, because it is relatively inexpensive and nontoxic at low concentrations. Rb is known to cause developmental problems in insects (probably through competitive binding with K) at much higher concentrations than we used, but we did not detect any evidence of toxicity at the levels used. The cost of Rb and of specimen analysis by atomic absorption spectrophotometry is moderate, compared to other marking techniques. We believe the method is an improvement over other marking techniques, and will facilitate the study of dispersal of aquatic insects, in cases where dispersing adults can be recaptured.