Use of natural sites and field hives by a long‐tongued bumble bee Bombus ruderatus

Features of the sites of. 12 natural Bombus ruderatus colonies are reported; most were subterranean. This species (and B. terrestris ) occupied 8‐32% of 23‐25 surface hives of bricks or pumice concrete, and 93% of 45 underground hives with earth floors and plastic roofs. High colony mortality, apparently caused by excessive condensation, occurred in plastic underground hives, but was remedied by replacing the plastic‐roofed nesting cavities with partly buried pumice‐concrete hives. The mean cocoon count In 16 completed B. ruderatus colonies was 418. A method for calculating a ‘productivity index’ based on mean sizes and numbers of worker or male and queen cocoons is described.