Showing papers on "Varroa sensitive hygiene published in 1999"

Heritability in Honey Bees (Hymenoptera: Apidae) of Characteristics Associated with Resistance to Varroa jacobsoni(Mesostigmata: Varroidae)

Abstract: This study uses sibling analysis to measure the heritability in honey bees, Apis mellifera L., of characteristics that have been associated with resistance to the mite, Varroa jacobsoni Oudemans. Twenty-eight uniform colonies of bees were established on 13 May in Baton Rouge, LA, each with 1 kg of mite-infested bees and a queen. The 28 unrelated queens in these colonies were divided into 7 groups of 4 based on the insemination of 4 queens with the same mixture of semen from 1 of 7 sire colonies. After worker progeny from these queens had replaced the initial bee populations, a colony was related as a full sister to the other 3 colonies in its sire group and unrelated to the other 24 colonies. Heritability ( h 2) was 1.24 for proportion of mites in brood, 0.65 for hygienic behavior, 0.89 for the duration of the capped period, 0.46 for suppression of mite reproduction, and 0.00 for physical damage to mites (measured by the presence of physically broken or dented mites on the bottom board). These results suggest that it should be possible to enhance the expression of 4 of these 5 characteristics with selective breeding of bees, thus reinforcing confidence in our ability to breed honey bees for resistance to V. jacobsoni.

The effect of insecticides on learning in the Africanized honey bee (Apis mellifera L.).

Abstract: The present study was designed to examine the effects of endosulfan, decis, baytroid, and sevin on the learning ability of Africanized honey bees (Apis mellifera L.). Although these insecticides were recommended by the government of Brazil to control the cotton boll weevil, the effects on bees have been unknown. Results of the present research show that: (1) bees readily consume each of the pesticides when placed in a sucrose solution; (2) the odors of the pesticides are not repellent to bees, and such odors can serve as conditioned stimuli; (3) learning occurs to various degrees when the insecticides are combined with the sucrose solution and used as an unconditioned stimulus; and (4) feeding the insecticides to the bees 1 h prior to conditioning leads to differing mortality. Because of the importance of bees for honey production, as well as pollination of cotton and other crops, recommendations are made for the use of decis and other measures for boll weevil control.

Occurrence of acute paralysis virus of the honey bee (Apis mellifera) in a Hungarian apiary infested with the parasitic mite Varroa jacobsoni.

Abstract: Viruses of the honey bee have been known for a long time; however, recently the attention of scientists and apiculturalists has turned towards the relationship between these viruses and the parasitic mite Varroa jacobsoni. Although clinical symptoms indicated the presence of some of the viruses of bees in Hungary, none have previously been isolated or identified. During July unusual adult bee and brood mortality was observed in some colonies of an apiary in Budapest known to be infested with Varroa jacobsoni. Large amounts of acute paralysis virus (APV) were detected serologically in healthy honey bee pupae killed by the injection of a bacteria-free extract of diseased adult bees. Crystalline arrays of 30 nm particles were seen in ultrathin sections of the tissues of injected pupae and naturally infected adult bees. In spite of the application of acaricide treatments the bee population in several colonies had collapsed by the end of summer and the apiary suffered severe wintering losses.

Varroa jacobsoni infestation of adult Africanized and Italian honey bees (Apis mellifera) in mixed colonies in Brazil

Abstract: Different levels of infestation with the mite Varroa jacobsoni have been observed in the various Apis mellifera races. In general, bees of European races are more susceptible to the mite than African honey bees and their hybrids. In Brazil honey bee colonies are not treated against the mite, though apparently both climate and bee race influence the mite infestation. Six mixed colonies were made with Italian and Africanized honey bees. The percentage infestation by this parasite was found to be significantly lower in adult Africanized (1.69 ± 0.44) than Italian bees (2.79 ± 0.65). This ratio was similar to that found in Mexico, even though the Africanized bees tested there had not been in contact with varroa, compared to more than 20 years of the coexistence in Brazil. However, mean mite infestation in Brazil on both kinds of bees was only about a third of that found in Mexico.

Effective biotechnical control of varroa: applying knowledge on brood cell invasion to trap honey bee parasites in drone brood

Abstract: SUMMARYBiotechnical methods of varroa (Varroa jacobsoni) control are based on the idea that mites inside brood cells are trapped and can then easily be removed from a honey bee (Apis mellifera) colony. Trapping is most efficient using drone brood in otherwise broodless colonies. In theory, one trap-comb with drone brood is enough to achieve control. We designed and tested two methods using trap-combs with drone brood. In the first experiment, effectiveness of the control method varied considerably, from 67% to 96%. However, the observed effectiveness in each separate colony was similar to the prediction based on knowledge of behaviour of mites invading brood cells. Effectiveness depended on the number of drone cells that had been available for mite trapping. In the second experiment, we adjusted the method to improve production of trap-combs with drone brood, since this appeared to be crucial for trapping efficiency. The observed effectiveness of 93.4% demonstrates that trap-combs with drone brood can eff...

Water requirements of adult females of the honey bee parasitic mite, Varroa jacobsoni (Acari: Varroidae) and implications for control

Abstract: This is the first demonstration of active water vapor uptake by the adult female honey bee parasitic mite, Varroa jacobsoni (Oudemans). Water vapor gain permits these ‘leaky’ mites to counter water loss and survive between meals. Their poor water-retention ability (fast net water loss rate) reveals a critical requirement for moisture. This is reflected by the stable, humid microhabitat of the bee colony environment and this mite's tropical origin. Water balance characteristics for mites from three states (Arizona, Minnesota and Pennsylvania) and a fluvalinate-resistant population (Pennsylvania) were identical. This implies that Varroa can occupy any region where beehives are located and strengthens the argument that resistance is biochemically-based. These results show that the hydrophilic-nature of V. jacobsoni has important implications for improving integrative pest management strategies.