Reproduction of Varroa destructor in worker brood of Africanized honey bees (Apis mellifera)

Reproduction and population growth of Varroa destructor was studied in ten naturally infested, Africanized honeybee (AHB) (Apis mellifera) colonies in Yucatan, Mexico. Between February 1997 and January 1998 monthly records of the amount of pollen, honey, sealed worker and drone brood were recorded. In addition, mite infestation levels of adult bees and worker brood and the fecundity of the mites reproducing in worker cells were determined. The mean number of sealed worker brood cells (10,070 ± 1,790) remained fairly constant over the experimental period in each colony. However, the presence and amount of sealed drone brood was very variable. One colony had drone brood for 10 months and another for only 1 month. Both the mean infestation level of worker brood (18.1 ± 8.4%) and adult bees (3.5 ± 1.3%) remained fairly constant over the study period and did not increase rapidly as is normally observed in European honey bees. In fact, the estimated mean number of mites fell from 3,500 in February 1997 to 2,380 in January 1998. In May 2000 the mean mite population in the study colonies was still only 1,821 mites. The fertility level of mites in this study was much higher (83–96%) than in AHB in Brazil(25–57%), and similar to that found in EHB (76–94%). Mite fertility remained high throughout the entire study and was not influenced by the amount of pollen, honey or worker brood in the colonies. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nutritional effects of supplementary diets on brood development,biological activities and honey production of Apis mellifera L

The present research work was conducted to assess the impact of nutrient-enriched diet on the physiological activities and subsequently honey yield. Eighteen colonies of Apis mellifera L. were selected from Dera Ismail Khan region, KPK, Pakistan, during the winter and summer seasons, 2019–2020. Five pollen supplement diets were prepared and provided to screen out the palatable one to be fed as pollen alternative nutrition to bee bread. Results of diet consumption regarding mean data for consumption rate displayed that soybean flour enriched artificial diet was maximally consumed (74.34 g) by honey bees per week. Minimum consumption was observed for grinded groundnut enriched diet (64.62 g) which was relatively lesser than the other tested artificial diets. Results of area of worker brood disclosed that soybean flour fortified diet (1489.27 cm²/colony) statistically noteworthy than the other artificial diets whereas control (463.51 cm²/colony) was least effective. Highest bee strength (10.00 bee frames/colony) was noted in the bee colonies fed with soybean flour fortified diet, date paste (8.0 bee frames/colony) was the next effective one, among the tested pollen replacement diets whereas relatively least (5 bee frames/colony) was noticed in case of grinded groundnut. Highest body weight (12.41 g) of neonate bees was noted in case of soybean enriched diet while lowermost (5.31 g) was noted in control bees. Results of wax cell built up and foraging efficiency were also superior in artificial diets than respective control bees. Hence, artificial diets especially soybean-enriched pollen alternative diet can boost up the physiology of honey bee leading to increased honey yield and profit.     

The relationship between population size,amount of brood,and individual foraging behaviour in the honey bee,Apis mellifera L.

This study experimentally examines the relationship between colony state and the behaviour of individual pollen and nectar foragers in the honey bee, Apis mellifera L. In the first experiment we test the prediction that individual pollen foragers from colonies with higher brood quantities should exhibit a greater work effort for pollen resources than individual pollen foragers from colonies with low brood quantities. Eight colonies were assigned into two treatment groups; HIGH brood colonies were manipulated to contain 9600±480 cm² brood area; LOW brood colonies were manipulated to contain 1600±80 cm² brood area. We measured colony brood levels over the course of the experiment and collected individual pollen loads from returning pollen foragers. We found that, while colonies remained significantly different in brood levels, individual pollen foragers from HIGH brood colonies collected larger loads than individuals from LOW brood colonies. In the second experiment we investigated the influence of colony size on the behaviour of individual nectar foragers. We assigned eight colonies to two treatment groups; LARGE colonies were manipulated to contain 35000±1700 adult workers with 3500±175 cm² brood area, and SMALL colonies were manipulated to contain 10000±500 adult workers with 1000±50 cm² brood area. We observed foraging trips of individually marked workers and found that individuals from LARGE colonies made longer foraging trips than those from SMALL colonies (LARGE: 1666.7±126.4 seconds, SMALL: 1210.8±157.6 seconds), and collected larter nectar loads (LARGE: 19.2±1.0 l, SMALL: 14.6±0.8 l). These results indicate that individual nectar foragers from LARGE colonies tend to work harder than individuals from SMALL colonies. Both experiments indicate that the values of nectar and pollen resources to a colony change depend on colony state, and that individual foragers modify their behaviour accordingly.     

The relationship between comb age and performance of honey bee (Apis mellifera) colonies

A study on the relationship between the age of comb and the activity of the hybrid Carniolan honey bee colonies in collecting pollen activity, worker brood production, colony strength, and honey yield was conducted. In comparison to colonies with combs aged 4-years, colonies with combs aged 1, 2 and 3-years significantly exceeded in the number returning workers, number returning workers with pollen loads, rate of storing pollen, rate of worker brood production, and size of colony population. Colonies with combs aged 1, 2 and 3-years produced significantly more honey than colonies with combs aged 4-years (5.25, 4.90 and 4.65 kg/colony vs. 4.45 kg/colony, respectively). It can be concluded that the foraging rate, gathering and storing pollen, brood production, colony population size, and honey yield significantly depended on the age of combs. Beekeepers can replace old combs with new ones to increase brood and honey production.     

Preparation for disturbance-induced absconding of Cape honeybee colonies (Apis mellifera capensis Esch.)

African honeybees, Apis mellifera, are characterised by frequent disturbance-induced absconding. However, the effectiveness in preparation before such disturbance-induced absconding has not been rigorously quantified yet. We investigated the effectiveness of preparation for disturbance-induced absconding by evaluating colony phenotypes prior to and after absconding in ten colonies of the Cape honeybee, A. m. capensis. Seven non-absconding colonies at the same apiary were used as controls. While seven absconded colonies left neither stores nor brood behind, three colonies abandoned only a small area of honey, pollen, open or capped brood. At the end of the observations, the control colonies still had pollen and honey stores and brood. The mean reduction rate between a major disturbance and the absconding event was 0.052 ± 0.018 cm² stores and open brood per worker per day. Our results demonstrate that disturbance-induced absconding can also occur with preparation, if the disturbance is not highly destructive and enough time for preparation is available. We conclude that Cape honeybee colonies can show a considerable high effectiveness in their preparation before disturbance-induced absconding, which limits the loss of colony resources. In light of the general high mobility of African honeybee colonies such an efficient behaviour is probably adaptive. Received 22 December 2004; revised 3 June 2005; accepted 13 June 2005.     

The effects of honey bee (Apis mellifera L.) queen reproductive potential on colony growth

Reproduction in species of eusocial insects is monopolized by one or a few individuals, while the remaining colony tasks are performed by the worker caste. This reproductive division of labor is exemplified by honey bees (Apis mellifera L.), in which a single, polyandrous queen is the sole colony member that lays fertilized eggs. Previous work has revealed that the developmental fate of honey bee queens is highly plastic, with queens raised from younger worker larvae exhibiting higher measures in several aspects of reproductive potential compared to queens raised from older worker larvae. Here, we investigated the effects of queen reproductive potential (“quality”) on the growth and winter survival of newly established honey bee colonies. We did so by comparing the growth of colonies headed by “high-quality” queens (i.e., those raised from young worker larvae, which are more queen-like morphologically) to those headed by “low-quality” queens (i.e., those raised from older worker larvae, which are more worker-like morphologically). We confirmed that queens reared from young worker larvae were significantly larger in size than queens reared from old worker larvae. We also found a significant positive effect of queen grafting age on a colony’s production of worker comb, drone comb, and stored food (honey and pollen), although we did not find a statistically significant difference in the production of worker and drone brood, worker population, and colony weight. Our results provide evidence that in honey bees, queen developmental plasticity influences several important measures of colony fitness. Thus, the present study supports the idea that a honey bee colony can be viewed (at least in part) as the expanded phenotype of its queen, and thus selection acting predominantly at the colony level can be congruent with that at the individual level.     

Development rate and brood production in haplo- and pleometrotic colonies of <Emphasis Type="Italic">Oecophylla smaragdina</Emphasis>

Pleometrosis (colony founding by multiple queens) may improve life history characteristics that are important for early colony survival. When queens unite their initial brood, the number of workers present when incipient colonies open may be higher than for single queen colonies. Further, the time until the first worker emerges may shorten. For territorial species and species that rob brood from neighbouring colonies, a faster production of more workers may improve the chance of surviving intraspecific competition. In this study, the time from the nuptial flight to the emergence of the first worker in incipient Oecophylla smaragdina Fabr. colonies founded by 1–5 queens was compared and the production of brood during the first 68 days after the nuptial flight was assessed. Compared to haplometrotic colonies, pleometrotic colonies produced 3.2 times more workers, their first worker emerged on average 4.3 days (8%) earlier and the queen’s per capita egg production almost doubled. Further, colony production was positively, correlated with the number of founding queens and time to worker emergence was negatively correlated. These results indicate that pleometrotic O. smaragdina colo-nies are competitively superior to haplometrotic colonies as they produce more workers faster and shorten the claustral phase, leading to increased queen fecundity.     

Performance evaluation of indigenous and exotic honey bee (Apis mellifera L.) races in Assir region,southwestern Saudi Arabia

This study was conducted in the Assir region of southwestern Saudi Arabia to compare the activities of honeybee colonies of indigenous Apis mellifera jemenitica (AMJ) and imported Apis mellifera carnica (AMC) during the late summer and autumn of 2009 and 2010. The results showed that the workers of the two races exhibited relatively similar forage timings throughout the period of study (August–November). The highest numbers of foraged workers were recorded at 6:00 am, 10:00 am and 6:00 pm, while the lowest numbers were recorded at 8:00 am, 12:00 pm and 4:00 pm. Although foraging activity was negatively affected by decreased temperature, AMJ was more resistant to cold than AMC. In the first season, the smallest amount of worker brood rearing was recorded in August, and the highest amount of rearing occurred in November in both races. In the second season, the smallest amount of brood was observed in October, and the largest amount of brood was observed in November. Brood rearing and pollen collecting was significantly (P < 0.05) higher in AMJ compared with AMC, while AMC stored significantly (P < 0.05) more honey than AMJ during the tested periods. In AMJ colonies, a positive significant correlation was observed between the area of the sealed worker brood and stored pollen, while a negative but nonsignificant correlation was observed between the area of the sealed worker brood and surplus honey. In the AMC colonies, a positive significant correlation was observed between the area of the sealed brood and the stored pollen and surplus honey.     

The Effect of Queen and Worker Adoption on Weaver Ant (Oecophylla smaragdina F.) Queen Fecundity

Incipient ant colonies are often under fierce competition, making fast growth crucial for survival. To increase production, colonies can adopt multiple queens (pleometrosis), fuse with other colonies or rob brood from neighboring colonies. However, different adoption strategies might have different impacts such as future queen fecundity or future colony size. O. smaragdina queen production was measured in incipient colonies with 2, 3 or 4 founding queens, following the transplantation of 0, 30 or 60 pupae from a donor colony. Pupae developed into mature workers, resulting in increased worker/queen ratios in pupae transplanted treatments and leading to increases in the per capita queen production. Conversely, more queens did not induce increased per capita fecundity. Thus, brood robbing added individuals to the worker force and increased future production of resident queens, whereas queen adoption increased the colony’s future production, but not the production of individual queens.     

Fitness and the level of homozygosity in a social insect

To date very few studies have addressed the effects of inbreeding in social Hymenoptera, perhaps because the costs of inbreeding are generally considered marginal owing to male haploidy whereby recessive deleterious alleles are strongly exposed to selection in males. Here, we present one of the first studies on the effects of queen and worker homozygosity on colony performance. In a wild population of the ant Formica exsecta, the relative investment of single‐queen colonies in sexual production decreased with increased worker homozygosity. This may either stem from increased homozygosity decreasing the likelihood of diploid brood to develop into queens or a lower efficiency of more homozygous workers at feeding larvae and thus a lower proportion of the female brood developing into queens. There was also a significant negative association between colony age and the level of queen but not worker homozygosity. This association may stem from inbreeding affecting queen lifespan and/or their fecundity, and thus colony survival. However, there was no association between queen homozygosity and colony size, suggesting that inbreeding affects colony survival as a result of inbred queens having a shorter lifespan rather than a lower fecundity. Finally, there was no significant association between either worker or queen homozygosity and the probability of successful colony founding, colony size and colony productivity, the three other traits studied. Overall, these results indicate that inbreeding depression may have important effects on colony fitness by affecting both the parental (queen) and offspring (worker) generations cohabiting within an ant colony.     

Effects of Brood Pheromone Modulated Brood Rearing Behaviors on Honey Bee (Apis mellifera L.) Colony Growth

A hallmark of eusociality is cooperative brood care. In most social insect systems brood rearing labor is divided between individuals working in the nest tending the queen and larvae, and foragers collecting food outside the nest. To place brood rearing division of labor within an evolutionary context, it is necessary to understand relationships between individuals in the nest engaged in brood care and colony growth in the honey bee. Here we examined responses of the queen, queen-worker interactions, and nursing behaviors to an increase in the brood rearing stimulus environment using brood pheromone. Colony pairs were derived from a single source and were headed by open-mated sister queens, for a total of four colony pairs. One colony of a pair was treated with 336 μg of brood pheromone, and the other a blank control. Queens in the brood pheromone treated colonies laid significantly more eggs, were fed longer, and were less idle compared to controls. Workers spent significantly more time cleaning cells in pheromone treatments. Increasing the brood rearing stimulus environment with the addition of brood pheromone significantly increased the tempo of brood rearing behaviors by bees working in the nest resulting in a significantly greater amount of brood reared.     

蜜蜂巢房大小影响狄斯瓦螨的繁殖行为

在具有相同类型幼虫的雄蜂和工蜂巢房中,人工接入狄斯瓦螨Varroa destructorAnderson&Trueman,比较巢房大小不同,对于螨繁殖的影响。结果显示:狄斯瓦螨在具有工蜂幼虫的工蜂房(WW)中的繁殖率为94.4%,而在具有工蜂幼虫的雄蜂房(WD)中繁殖率只有27.7%,差异极显著。在具有工蜂幼虫的工蜂房中,每只雌螨产出后代的平均数为3.35±1.56只;在具有工蜂幼虫的雄蜂房中每只雌螨产出后代的平均数为0.49±0.93只,差异极显著。表明:在具有相同类型幼虫存在的情况下,狄斯瓦螨喜欢较小的巢房,狄斯瓦螨在较小巢房中的繁殖能力明显高于较大的巢房。     

Behavior of varroa mites in worker brood cells of Africanized honey bees

The ectoparasitic mite Varroa destructor is currently the most important pest of the honey bee, Apis mellifera. Because mite reproduction occurs within the sealed cell, the direct observation of varroa activity inside the cell is difficult. A video observation method using transparent polystyrol cells containing infested brood was used to analyze the behavior of varroa mites in worker brood of Africanized honey bees. We recorded how mites feed on the larva and pupa, construct a fecal accumulation site and how the bee larva carried out some longitudinal movements around the cell. The feeding activity of the foundress mite varies during the course of the cycle. On the prepupa mites were found to feed often (0.3 ± 0.2 bouts h⁻¹) for a period of 8.7 ± 8.4 min h⁻¹ and there was no preference for a specific segment as feeding site. On the opposite, during the pupal stage mites fed less often (0.1 ± 0.1 bouts h⁻¹) for a period of 6.2 ± 4.0 min h⁻¹ and almost always at a particular site (92.4%). On pupa, 83.7% of the feeding was on the 2nd abdominal segment (n = 92), and only few perforations were found on the thorax. Varroa shows a preference for defecation in the posterior part of the cell (cell apex), close to the bee′s anal zone. We found a high correlation between the position of the feeding site on the pupa and the position of the fecal accumulation on the cell wall. Most infested cells have only one fecal accumulation site and it was the favorite resting site for the mite, where it spent 24.3 ± 3.9 min h⁻¹. Longitudinal displacements were observed in 28.0% (n = 25) of the analyzed bee larvae. Turning movements around the cell, from the bottom to the top, were carried out by these larvae, mainly during the second day (47.7 ± 22.5 min h⁻¹), just before pupation, with a total time of 874.9 ± 262.2 min day⁻¹ (n = 7 individuals). These results in worker brood of Africanized bees demonstrate adaptations of varroa mites to parasitizing the developing bee inside the capped brood cells.     

不同人工代花粉对蜂群群势和生产性能的影响

早春将群势、蜂王年龄和质量基本一致的25群意大利蜜蜂Apis melliferaL.,随机分为5个处理,分别饲喂纯花粉和4种不同的人工代用花粉,观测它们对蜂群群势和生产性能的影响。结果表明,含有添加剂的各代用花粉组与纯花粉组的蜂群的蜂子数量差异均不显著,但均显著高于纯豆粕组(P<0.01);各组产蜜量随着纯花粉所占比例的减少而呈现递减的趋势,但饲喂含有60%花粉+40%豆粕+添加剂1组与纯花粉组没有明显的差异;含有添加剂的各代用花粉组的王台接受率均显著高于纯花粉组(P<0.01);饲喂含有添加剂的各代用花粉组与饲喂纯花粉组相比,王浆产量及蜂王浆中的10-HDA、水分、蛋白质的含量及酸度均没有差异。     

Drone and Worker Brood Microclimates Are Regulated Differentially in Honey Bees,Apis mellifera

Background

Honey bee (Apis mellifera) drones and workers show differences in morphology, physiology, and behavior. Because the functions of drones are more related to colony reproduction, and those of workers relate to both survival and reproduction, we hypothesize that the microclimate for worker brood is more precisely regulated than that of drone brood.

Methodology/Principal Findings

We assessed temperature and relative humidity (RH) inside honey bee colonies for both drone and worker brood throughout the three-stage development period, using digital HOBO^® Data Loggers. The major findings of this study are that 1) both drone and worker castes show the highest temperature for eggs, followed by larvae and then pupae; 2) temperature in drones are maintained at higher precision (smaller variance) in drone eggs and larvae, but at a lower precision in pupae than the corresponding stages of workers; 3) RH regulation showed higher variance in drone than workers across all brood stages; and 4) RH regulation seems largely due to regulation by workers, as the contribution from empty honey combs are much smaller compared to that from adult workers.

Conclusions/Significance

We conclude that honey bee colonies maintain both temperature and humidity actively; that the microclimate for sealed drone brood is less precisely regulated than worker brood; and that combs with honey contribute very little to the increase of RH in honey bee colonies. These findings increase our understanding of microclimate regulation in honey bees and may have implications for beekeeping practices.     

The impact of caging the queens during the flow season on some biological activities of honeybee colonies

This study was achieved in a private apiary located in a banana farm in Sa El Hagar, Basioun, Gharbia, Egypt from August 15, 2019 to May 25, 2020, including the banana (Musa sp., Musaceae) flow season (August and September) and extend to Egyptian clover (Trifolium alexandrinum L., Fabaceae) flow season (May). The study aimed to evaluate the effect of confining the queen during the banana flow season on the brood rearing, honey yield, and activation of worker's ovaries. Also, we determined the negative impact of caging the queen during the banana flow season on the activity of the colony in brood rearing, storing pollen, and honey yield after releasing the queen on 5 October, extending to the next flow season in May. The obtained results showed that the honeybee colonies with the caged queen produced significantly more honey yield and less brood production than the free queen ones during the banana flow season. Also, the caging of the queen did not affect the colony strength after releasing the queen despite the partial development of the ovaries of some workers, but they did not lay eggs. In addition, releasing the queens suppressed the ovaries of the laying workers. It can be concluded that caging the queen during the banana flow season helps the colonies to produce more honey yield without effect on the colony strength after releasing the queen despite the ovaries development of few workers without egg-laying.     

Effect of primer pheromones and pollen diet on the food producing glands of worker honey bees (Apis mellifera L.)

Cooperative brood care is highly developed in the honey bee such that workers called nurses use their hypopharyngeal and mandibular glands to biosynthesize proteinaceous secretions that are progressively provisioned to larvae. The role that honey bee primer pheromones play in the functional physiology of food producing glands was examined. The combined and separate effects of queen mandibular pheromone (QMP) and brood pheromone (BP) on amount of protein extractable from hypopharyngeal and mandibular glands of workers reared for 12 days with and without pollen diets was measured. In rearing environments with a pollen diet, BP, and QMP + BP pheromone treatments significantly increased extractable protein from both glands. Bees reared with QMP + pollen had amounts of protein extractable from both glands that were not significantly different from control bees (no pheromones, no pollen). Pollen in the diet alone significantly increased amounts of protein extractable from glands versus control. In rearing environments without pollen, QMP + BP had a synergizing effect on amount of protein in both glands. The QMP + BP treatment was the only rearing environment without a pollen diet where protein amounts were significantly greater than the control. The synergizing effect of QMP + BP on extractable mandibular and hypopharyngeal gland protein suggests a highly derived role for the combined effect of these two primer pheromones on honey bee cooperative brood care. Mandibular gland area was significantly and positively correlated with extractable protein. Amounts of extractable protein from both glands declined significantly with age of workers in all treatments. However, treatment significantly affected rate of decline. The adaptive significance of gland protein amounts in response to pheromones and pollen diet are discussed.     

Sterol utilization in honey bees fed a synthetic diet: Effects on brood rearing

The dietary sterols, cholesterol, campesterol, sitosterol, stigmasterol and 24-methylenecholesterol, were tested for their ability to support brood rearing in the honey bee, Apis mellifera L., by adding them singly to a chemically-defined worker bee diet. Diet supplemented with 24-methylenecholesterol supported the greatest survival of worker bees, but diet supplemented with either 24-methylenecholesterol or cholesterol supported the production of nearly equivalent amounts of sealed brood and more than any of the other three sterols tested. Diets containing stigmasterol, sitosterol, campesterol, or no supplement produced less sealed brood, in decreasing order.     

Optimal colony fissioning in social insects: testing an inclusive fitness model with honey bees

In most species of social insects, when a queen departs from her parental nest to found a new colony, she leaves on her own. In some species, however, the departing queen leaves accompanied by a portion of the parental colony’s workers and there is a permanent fissioning of the worker force. Little is known about how the adult workers in colonies of fissioning species distribute themselves between the old and the new colonies. We examined this problem, building on Bulmer’s (J Theor Biol 100: 329–339, 1983) model for the optimal splitting of a colony’s adult workforce during colony reproduction. We first created an inclusive fitness model of optimal colony fissioning that applies to species in which fissioning gives rise to two autonomous colonies. The model predicts the optimal “swarm fraction”, which we define as the proportion of the adult workers in a fissioning colony that join the departing queen. We then tested the model by comparing the predicted and observed swarm fractions in honey bees. We found a close match between predicted (0.76–0.77) and observed (0.72 ± 0.04) swarm fractions. Evidently, worker honey bees distribute themselves between the old and new colonies in a way that jointly maximizes the inclusive fitness of each worker. We conclude by discussing additional ways to test the model.     

Effect of queen excluders on ovary activation in workers of the Eastern honeybee Apis cerana

Honeybee workers generally refrain from personal reproduction when a queen is present. Workers discern the presence and fecundity of the queen via volatile pheromones that permeate throughout the colony. Pheromones are emitted both by the queen herself and by the brood that she produces. If pheromone production is disrupted, some workers initiate egg laying. The Eastern honeybee Apis cerana is unusual in that workers have high levels of ovary activation even in the presence of a queen. To investigate the effect of disruption to pheromone dispersal, we fitted three A. cerana colonies with vertical queen excluders, thus splitting the colonies into a half containing a queen and a half without a queen. We regularly sampled adult workers from both sides of the excluder for 3 weeks. We also sampled workers from three control colonies that did not contain excluders. We found a significant increase in worker ovary activation 3 days after addition of excluders, suggesting that the reduced dispersal of pheromones allowed some workers to become reproductively active. Workers attempted to rear queen cells on the queenless halves of all three colonies. Queen-rearing ceased on day 9, at which time no queen-laid brood remained on the queenless halves of the colonies. Ovary activation rates continued to climb until day 9 and then gradually began to decline. With the exception of one egg, we did not observe worker-laid brood on the queenless side of the colonies, suggesting that workers continued policing eggs laid by workers. We conclude that if the distribution of brood pheromone is impeded, workers prepare to supersede their queen, accompanied by high levels of worker ovary activation. However, because workers continue to police each other, high ovary activation does not result in worker-produced drones.