Varroa sensitive hygiene

About: Varroa sensitive hygiene is a research topic. Over the lifetime, 714 publications have been published within this topic receiving 24928 citations. The topic is also known as: VSH.

A semiochemical from brood cells infested by Varroa destructor triggers hygienic behaviour in Apis mellifera

Abstract: Hygienic behaviour of bees towards mite infested brood is involved in the tolerance of some bee strains to Varroa destructor. The stimuli triggering hygienic behaviour are olfactory cues emanating from cells containing infested brood but their identity is still unknown. After confirming the capacity of bees to detect and empty mite-infested cells, we studied the volatile chemicals released by artificially infested worker brood cells by means of SPME-GC-MS. The identified chemicals were then bioassayed by comparing the bees' hygienic behaviour towards treated cells into which 1 µg of each compound was injected and control cells which received the solvent alone. Z-(6)-pentadecene significantly increased the number of cells emptied by the bees. Varroa destructor / semiochemicals / hygienic behaviour / removal / hydrocarbons

Africanized honey bees (Apis mellifera L.) are more efficient at removing worker brood artificially infested with the parasitic mite Varroa jacobsoni Oudemans than are Italian bees or Italian/Africanized hybrids

Abstract: Africanized honey bees are more tolerant of infestations with the mite Varroa jacobsoni than are honey bees of European origin. The capacity of these bees to detect and react to brood infested with this mite could be one of the factors determining this tolerance. We tested colonies of Africanized bees headed by queens from swarms collected in Ribeirao Preto, Sao Paulo State. The Italian colonies had queens imported directly from the USA, or from the Brazilian Island of Fernando de Noronha, where varroa-infested Italian colonies have been maintained, untreated, since 1984. Recently sealed worker brood cells were artificially infested by opening the cell capping, inserting live adult female mites and resealing the cells. Control cells were treated in the same way, but without introducing mites. The ability of the Africanized honey bees to recognize and remove this artificially infested brood was compared with that of first generation Italian/Africanized hybrid bees, and with the two groups of "pure" Italian bees, in three separate experiments. Africanized colonies removed a mean of 51% of the infested brood, while Italian/Africanized hybrid colonies removed 25%. Africanized colonies also removed a significantly greater proportion of infested brood than did Italian colonies, headed by queens from the USA (59 vs. 31%, respectively). Similarly, when Africanized colonies were compared with colonies of Italian bees from Fernando de Noronha, the former were found to be significantly more efficient at removing infested brood (61 vs. 35%, respectively), even though the population of Italian bees on this island has been exposed to and survived varroa infestations (without treatment) for more than 12 years. Only the Africanized honey bees removed a significant proportion of varroa-infested brood, when the data was corrected for brood removal from control cells.

Three QTL in the honey bee Apis mellifera L. suppress reproduction of the parasitic mite Varroa destructor

Abstract: Varroa destructor is a highly virulent ectoparasitic mite of the honey bee Apis mellifera and a major cause of colony losses for global apiculture. Typically, chemical treatment is essential to control the parasite population in the honey bee colony. Nevertheless a few honey bee populations survive mite infestation without any treatment. We used one such Varroa mite tolerant honey bee lineage from the island of Gotland, Sweden, to identify quantitative trait loci (QTL) controlling reduced mite reproduction. We crossed a queen from this tolerant population with drones from susceptible colonies to rear hybrid queens. Two hybrid queens were used to produce a mapping population of haploid drones. We discriminated drone pupae with and without mite reproduction, and screened the genome for potential QTL using a total of 216 heterozygous microsatellite markers in a bulk segregant analysis. Subsequently, we fine mapped three candidate target regions on chromosomes 4, 7, and 9. Although the individual effect of these three QTL was found to be relatively small, the set of all three had significant impact on suppression of V. destructor reproduction by epistasis. Although it is in principle possible to use these loci for marker-assisted selection, the strong epistatic effects between the three loci complicate selective breeding programs with the Gotland Varroa tolerant honey bee stock.

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.

The influence of the mite varroa jacobsoni oud. on the protein concentration and the haemolymph volume of the brood of worker bees and drones of the honey bee apis mellifera l

Abstract: Protein concentrations in the haemolymph of non-infected and varroa-infected worker and drone brood were examined by a photometric method. The determination of the haemolymph volume was carried out by the [14C] dnulin dilution method. The results of these two measurements were used to calculate the total protein content in the haemolymph of the worker and drone pupae (brown eyes). The findings showed that the worker and the drone brood react differently to varroa infestation.