Use of Rubidium to Label Lysiphlebus testaceipes (Hymenoptera: Braconidae), a Parasitoid of Greenbugs (Homoptera: Aphididae), for Dispersal Studies

Abstract

A reliable method of labeling is needed to study dispersal of the braconid parasitoid, Lysiphlebus testaceipes (Cresson), an important biological control of greenbugs, Schizaphis graminum (Rondani), on grain sorghum, Sorghum bieolor (L.) Moench. The feasibility of using aqueous solutions of rubidium chloride (RbCl) applied as a foliar spray or soil drench to label greenbugs and 1. testaceipes developing within greenbugs was studied. Laboratory and field studies were conducted to identify the minimal concentration of RbCl to assure labeling of greenbugs and wasps, persistence of Rb throughout the wasp's life span, mobility of Rb to unsprayed sorghum leaves, and feasibility of studying dispersal using a release-recapture technique with Rb-labeled wasps. Both greenbugs and wasps could be labeled using RbCl at concentrations of 2,500-10,000 ppm. Rubidium content in labeled wasps did not significantly vary during the first 7 d after emergence. Greenbugs feeding on unsprayed leaves were labeled up to 4 wk after leaves were sprayed. Rb-labeled wasps were found at the maximum trap distance from the release site (60 m) within 1 d after release.

Plants and Leaf Characteristics Influencing the Predaceous MiteKampimodromus aberrans(Acari: Phytoseiidae) in Habitats Surrounding Vineyards

“…Rubidium (rb ϩ ) has been widely used to test water uptake by organisms (Beery et al 1972, Graham et al 1978, Fernandes et al 1978. Water can be taken up by plants, and then by predaceous mites either from the plant or from phytophagous mites that have fed (Frazer andRaworth 1974, Jackson 1991).…”

Evaluation of Rubidium Chloride and Cesium Chloride Incorporated in a Meridic Diet to MarkDiatraea grandiosella(Lepidoptera: Crambidae) for Dispersal Studies

“…Rubidium (Rb) and cesium (Cs) have been used to mark insects physiologically (Berry et al 1972;Van Steenwyk 1982, 1984;Fernandes et al 1997;Prasifka et al 2001;Jost and Pitre 2002). Moss and Van Steenwyk (1984) pointed out that Rb and Cs could be used in dispersal experiments to give three (Rb, Cs, and Rb/Cs) distinct markers.…”

Field Testing Rubidium Marking for Quantifying Intercrop Movement of Predatory Arthropods

“…Both sucking and chewing pests are marked by feeding on Rb-augmented plants (Graham et al 1978, Fernandes et al 1997, whereas predators are marked through consumption of marked herbivores (Graham et al 1978, Johnson andReeves 1995) or possibly by feeding on the nectar and pollen of marked plants. Parasitoids can become marked by developing within Rb-enhanced hosts (Jackson et al 1988, Fernandes et al 1997, and probably by direct host-feeding as well.…”