Uncapping of worker bee brood, a component of the hygienic behavior of Africanized honey bees against the mite Varroa jacobsoni Oudemans Maria-Helena Corrêa-Marques, David de Jong To cite this version: Maria-Helena Corrêa-Marques, David de Jong. Uncapping of worker bee brood, a component of the hygienic behavior of Africanized honey bees against the mite Varroa jacobsoni Oudemans. Apidologie, Springer Verlag, 1998, 29 (3), pp.283-289. hal-00891494 HAL Id: hal-00891494 https://hal.archives-ouvertes.fr/hal-00891494 Submitted on 1 Jan 1998 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Original article Uncapping of worker bee brood, a component of the hygienic behavior of Africanized honey bees against the mite Varroa jacobsoni Oudemans Maria-Helena Corrêa-Marques )avid De Jong aEntomology Section, Faculdade de Filosofia, Ciências e Letras, Universidade de Sâo Paulo, 14.049-901 Ribeirâo Preto, SP, Brazil bGenetics Department, Faculdade de Medicina, USP, 14.049-900 Ribeirão Preto, SP, Brazil (Received 18 January 1997; accepted 24 October 1997) Abstract - Prematurely uncapped worker brood cells, possibly an initial phase of hygienic behav- ior, were found in ten Africanized honey bee colonies in Brazil. Among 360 such cells, 46 % contained the mite Varroa jacobsoni. A mean of 12 % of the normal, capped, worker brood cells were infested in the same colonies. In 18 % of the uncapped cells there were feces of larvae of the greater wax moth (Galleria mellonella), but no indication of mites. The remaining cells had no signs of either, or of any other abnormality that might have provoked the bees to uncap the cells. White-bodied pupae, with lightly pigmented eyes were the phase most frequently found to be uncapped, and represented 53 % of the total. The nearly four times higher infestation rate in prematurely uncapped cells shows that the bees selectively uncap cells infested with Varroa jacobsoni. © Inra/DIB/AGIB/Elsevier, Paris Varroa jacobsoni / Africanized bee / resistance / Galleria mellonella / hygienic behavior 1. INTRODUCTION detect the mite(s) and/or the damage that they cause to the bee pupa, uncap the cell Removal of infested brood is consid- and remove the parasitized brood. The ered an important mechanism of resistance odor of the mite itself influences this of the Asian honey bee Apis cerana Fabr. behavior. A. cerana is especially sensitive to the mite Varroa jacobsoni Oudemans to V. jacobsoni artificially introduced from [18, 19, 20, 22, 25]. The bees somehow A.mellifera L. colonies. A. mellifera can * Correspondence and reprints also detect and remove V. jacobsoni infes- frame Langstroth hives, with 4-7 frames of ted brood, but to a much lesser extent [22]. brood. Initially a single colony, in which ope- ned brood cells were noticeable, was examined Africanized honey bees in the southern ten times, during a period of 2 weeks. Each part of South America are resistant to V. day three combs of sealed brood were removed jacobsoni and are maintained without any and scanned visually for the presence of pre- kind of treatment [5, 23]. Infestation levels maturely uncapped cells. Whenever a cell was found to be it was examined care- are lower in Africanized colonies than in uncapped, A was used to remove the bees and Euro- fully. forceps pupa, European first-generation with aid of a fibreoptic light to illuminate the pean/Africanized hybrids kept under the interior of the cell. The cells and pupae were same conditions [6, 10, 11, 15]. This appa- examined for V. jacobsoni and other foreign rent resistance of the Africanized honey entities that might have provoked the premature bees has been attributed to various fac- uncapping. These pupae were also examined to search for abnormalities that could tors, including reduced mite fertility [21], externally have the bees to the cells, and fewer mite infestations provoked uncap progeny [2], lower to determine the developmental phase of the in the smaller brood cells of Africanized pupae. The developmental phases were clas- versus European honey bees [9, 12] and sified according to Issa [8] and Michelette and more efficient adult grooming behavior Soares [13] for Africanized honey bees: WP [14, 16]. The infestation levels are in fact = white pupa (with white eyes) 10.9-12.6 d; decreasing in the Africanized bee colo- PEP = pink-eyed pupa (white body, pink to brown 12.6-15.7 d; LP = nies in Brazil [17]. However the relative eyes) lightly pig- mented pupa (brown eyes and lightly pigmen- of these resistance importance apparent ted body) 15.7-18.4 days; DP = darkly pig- factors is still not clear, and other key fac- mented pupa (with brown eyes) 18.4-19.2 d. tors be involved. may The other nine Africanized colonies, in Prematurely uncapped worker brood which opened brood cells were found, were was occasionally found during a study of examined in the same way, though only two infestation rates of Africani- to three times each. The brood cells were clas- V. jacobsoni sified into three distinct zed bee colonies [3]. As these cells often categories: 1) presence of V. jacobsoni, 2) pupa spotted with faeces contained V. we decided to exa- jacobsoni, of the greater wax moth (G. mellonella L.) and mine them in order to determine if their 3) pupa with no damage, or partially removed, being uncapped was a consequence of the with no indication of V. jacobsoni or wax Africanized bees, reaction to the mite infes- moths. tation. The V. jacobsoni infestation rate was deter- mined for worker brood in all ten colonies. Sealed brood was analysed in 100 cells, 50 2. MATERIALS AND METHODS cells on each side of a comb. The honey bee colonies used in this study were all Africanized, headed by queens cap- 3. RESULTS tured in swarms, or by their descendants, kept in the University of São Paulo apiary in A total of 360 brood cells were found Ribeirão Preto, São Paulo state (620 m alti- tude, 21°11’25" south latitude). The data for prematurely uncapped. About half of these eight colonies were collected May-June 1995. contained pupae with pink to brown eyes These were selected by visually examining the and white bodies (PEP, table I). The next brood of 45 colonies for wor- patterns opened most frequent stage found was lightly pig- ker brood cells. An additional two colonies mented with brown were examined in 1997. These two had pupae eyes (LP). August About 7 % of the cells contained the most opened brood cells among 32 colo- pupae nies examined during a 2-d period. All colonies that were missing a head, and/or other were kept in single storey, standard deep ten- body parts. These were classified as unde- fined (UD), as it was not possible to verify The mean brood infestation rate among the brood development stage. The diffe- the ten colonies was 11.9 %, significantly rences in the proportions of the pupal less than the infestation rate of the pre- developmental phases found in these maturely uncapped cells in the same colo- uncapped cells were highly significant nies (P < 0.05, binomial test, and test for (test for n proportions [7]. n proportions [7]). This implies that the bees selectively uncapped brood cells About 53 % of the uncapped cells with containing V. jacobsoni. intact pupae contained V. jacobsoni, or signs of the mites (table II). Most of these About 18 % of the cells contained contained the original female mites with pupae covered with faeces of the greater progeny. A few contained only mite pro- wax moth, Galleria mellonella. Rarely, geny, without the original mother mites, the wax moth larvae were seen. A few which had apparently left. In others only were collected and reared to adult to ’fresh’ mite faeces were present, indica- confirm the species identification. Some ting that the mites had left (or been remo- bee pupae had only a small amount of ved) after the bees had uncapped the cells. faeces, others were nearly completely All of the cells containing only adult covered. No cells were found containing female mites, also had normal quantities of both V. jacobsoni and wax moth faeces. mite faeces, indicating that none of these The remaining cells (about 36 %) had no were infested after the cells were uncap- sign of V. jacobsoni or wax moths. As ped. there was no indication of damage, it was not clear why they were uncapped by the The worker brood cells found uncap- bees, though it is possible that early instar ped were considerably (nearly four times) wax moth larvae had passed through these more infested with V. jacobsoni than the cells without leaving faeces. Less than 1 % ’normal’ capped brood cells. If the bees of the ’normal’ sealed brood cells exami- continued this removal process and des- ned for V. jacobsoni infestation contained troyed the mites, or at least destroyed the wax moth faeces (data not shown), so it nymphal stages, then this uncapping beha- is apparent that attack by the wax moths vior would help the bees keep the mites also significantly (P < 0.05, binomial test, in check. This may be one of the factors and test for n proportions [7]) influences responsible for the ability of Africanized the tendency to uncap the brood cells.