Uptake and elimination of rubidium, a physiological marker, in adult Lygus lineolaris (Hemiptera: Miridae)

Patterns of uptake and elimination of Rb in Lygus lineolaris (Palisot de Beauvois) adults caged on mustard (Brassica juncea (L.) Cross.) sprayed with varying rates of Rb were studied in the greenhouse. Uptake for the initial 216 h generally followed a rectangular hyperbolic model over time, which uptake rate decreasing with time and approaching a horizontal asymptote within 10-80 h. The asymptote increased with increasing spray rates up to 12,000 ppm Rb, after which three was little further increase. After incorporation of the mark, however, insects removed from enriched host material and held on green beans (Phaseolus vulgaris L.) quickly lost most of the Rb, and elimination followed an exponential decay curve. Elimination data showed that the mark could be confidently maintained above endogenous levels for 2-4 day after leaving enriched host material.