Influence of the presence of Cacoxenus indagator Loew. parasite larvae in brood chambers on the emergence rate and size of red mason bees

Abstract

Cacoxenus indagator is one of cleptoparasites most frequently found in the nests of Osmia bicornis L. The goal of this experiment was to examine the influence of the presence of 2-3 C. indagator larvae in the brood chamber on the cocoon mass, on the mass and size of bee imagines, and on their emergence rate. During the analysis of red mason bee nest material, 200 cocoons were taken from brood chambers, each of them also containing 2-3 larvae of C. indagator (CC). The control group consisted of 200 randomly chosen cocoons from brood chambers with no parasites inside (CFFC). The cocoons and the emerged bees were weighed, and then the size of the bees was determined by the microscope image analysis software Axio Vision Rel. 4.0 coupled with a Stereo Lumar V12 stereoscopic microscope (Carl Zeiss, Germany). This involved measuring the sum of the widths of tergites 3 and 4, the distance between the wings and the forewing length and width. It was found that the presence of 2-3 C. indagator larvae in the brood chamber had no impact on the mortality of bees in cocoons. The research demonstrates that CC cocoons do not have to be removed when collecting cocoons from artificial nests in managed O. bicornis populations, as bees emerging from such cocoons are fully developed.

The Impact of Different Biotopes and Management Practices on the Burden of Parasites in Artificial Nests of Osmia spp. (Megachilidae) Bees

“…The same authors determined that in comparison with one-year-old tubes, in the two-yearold cane tubes there are more than ten times less healthy cocoons and three times more injured or destroyed cocoons, with a wider diversity of parasites [33]. Additionally, it was previously reported that continuous breeding in the same place for more than ten years means significantly higher numbers and diversity of brood parasites in nests [34,35]. Our results showed the lowest determined bees SL was at L3, which was 13.80% in total, while in a similar environment of L2, it was 28.05%.…”