A method to feed individual bees (Hymenoptera: Apiformes) known amounts of pesticides

Abstract

-We devised a simple method ("flower") to feed bees individually, and compared it with two other methods commonly used ("film canister" and "glass vial"). We tested the three methods on two solitary species, Osmia lignaria and Megachile rotundata, and one social species, Apis mellifera, under four different light regimes (natural, artificial, plant growth and darkness). The flower method was the most effective for all three bee species: 90-95% of the bees fed under natural light, 80-95% under artificial light, 75-100% under plant growth light, and 45-70% in darkness. Percent success was 0-50% with the film canister method, and 0-60% with the glass vial method. The flower method may allow more comprehensive future evaluation of pesticide effects on bees. oral toxicity test / individual feeding / Osmia lignaria / Apis mellifera / Megachile rotundata

Evaluation of a standard artificial flower design to feed individual bees known amounts of pesticides

“…A tiny plastic ampoule (inside diameter 2 mm, outside diameter 3 mm, height 5 mm), in which the test solution could be later pipetted, was inserted into the well. The plastic ampoule was built as described in Ladurner et al (2003).…”

“…Feeding units were placed in an incubator below two 15W Cool White Sylvania ® fluorescent tubes (Ladurner et al, 2003). Ten µL of test solution (25% v/v sucrose in water), pipetted into the plastic ampoule, were offered to each bee for 1 h. Ampoules were then visually inspected and scored as either empty or full (the bee had not consumed the solution).…”

“…For comparative purposes, we also tested 30 untrained individuals of each species (naive O. lignaria and M. rotundata, experienced A. mellifera) using the natural flower method (Ladurner et al, 2003) with periwinkle (Vinca minor L.) flowers. The reproductive column was substituted with a plastic ampoule, identical to the one described above, and inserted into a well drilled into a piece of green florists' dry foam identical to that used with artificial flowers.…”

“…In fact, acute toxicity studies on non-Apis bees often omit oral tests because it is difficult to feed individual bees known amounts of test solutions (Taséi, 2002). We therefore devised a simple method to feed bees individually known amounts of pesticides ("flower method"; Ladurner et al, 2003). With this method, individual bees were confined in an ice cream cup and offered the test solution in a natural flower whose reproductive column had been removed and replaced with a tiny ampoule into which the test solution was pipetted.…”

“…With this method, individual bees were confined in an ice cream cup and offered the test solution in a natural flower whose reproductive column had been removed and replaced with a tiny ampoule into which the test solution was pipetted. We compared the effectiveness of the flower method with two other methods commonly used with bees not performing trophallaxis ("film canister" and "glass vial" methods; after Johansen et al, 1984;van der Steen et al, 1996;Bortolotti et al, 2002;Patetta et al, 2002) and tested the three methods on two solitary species, O. lignaria and Megachile rotundata (Fabricius) (Megachilidae), and one social species, A. mellifera (Ladurner et al, 2003). The flower method turned out to be a simple, highly effective procedure: under artificial light, the percentage of bees that consumed the test solution within 1 h (percent feeding success) ranged 380 E. Ladurner et al from 80 to 95% in all three bee species.…”