No abstract

most, of the tortoise races were extinct, and that most Eleven of the original 15 races of Galapagos tortoises are of the surviving populations were imminently in known to survive. The populations of three of these may be danger of the same fate (Van Denburgh,

Honey bees (Apis mellifera L.) bred for Varroa sensitive hygiene (VSH) selectively remove pupae infested with Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae) from capped brood that is inserted into the nest. After 1 wk, remaining brood cells tend to have been uncapped and recapped, and remaining mites are mostly infertile. A primary goal of this experiment was to compare the reproductive status of mites that remained in recapped and normally capped cells after a 1-wk exposure to VSH and control colonies. Differences in distribution of fertile mites in normally capped brood cells between VSH bees and control bees may suggest that the stimulus for hygiene is related to reproduction by mites. Identification of stimuli triggering VSH behavior could be used to develop new bioassays for selective breeding of this important resistance mechanism. Combs of capped brood that were exposed to control bees had 10 times more pupae with fertile mites in normally capped brood as did VSH bees (6.7 and 0.7%, respectively). They also had 3 times more pupae with infertile mites in normally capped brood than did VSH bees (1.4 and 0.5%, respectively). Thus, VSH bees targeted fertile mites by a 3:1 ratio by either removing or uncapping and recapping their host pupae. Biased removal of mite-infested pupae with fertile mites suggested that stimuli triggering VSH behavior were enhanced by the presence of mite offspring within the brood cell. This bias for fertile mites is not seen during experiments of short 3-h duration. The differing results are discussed relative to a behavioral threshold model for hygienic behavior in honey bees in which different experimental protocols may reflect activities of honey bees having different sensitivities to pupae infested by fertile mites. In addition, mortality of mite offspring was significantly higher in recapped cells than in normally capped cells and contributed to decreased reproduction by the mites.

Varroa sensitive hygiene (VSH) is a trait of honey bees, Apis mellifera L. (Hymenoptera: Apidae), which supports resistance to Varroa destructor Anderson & Trueman. VSH is the hygienic removal of mite-infested pupa. Bees selectively bred for VSH produce colonies in which the fertility of mites decreases over time. In addition, mite fertility decreases after infested brood is exposed to VSH bees for 1 wk. The purpose of this study was to decide whether the reduction in mite fertility is caused by selective removal of mites that produce offspring. Initially, we monitored changes in a small patch of capped brood during exposure to VSH bees at 2-h intervals through 60 h, which provided a reference for the subsequent experiment. The first test showed that VSH bees uncapped, recapped, and began to remove many pupae in ≈2 h. The approach in the second experiment was to compare the percentage of fertile mites from brood exposed to VSH bees for a 3-h period to the percentage of fertile mites in brood that was protected from hygiene by a screen. There were no significant differences in fertility between mites on pupae that were being removed by the bees and mites on protected pupae. These results suggest that neither egg-laying by foundress mites nor mite offspring are the stimuli that trigger hygienic removal of mite-infested pupae by VSH bees. It may be that hygienic activities such as the uncapping of brood cells inhibits or disrupts reproduction by varroa mites.

No abstract

No abstract

No abstract

No abstract