African Honey Research Articles

Seasonal cycles of growth, development and movement of the African honey bee,Apis mellifera scutettata, in Africa

The relationship between the annual colony cycle and seasonal patterns of forage availability was investigated for the African honey bee,Apis mellifera scutellata, in the Okavango River Delta, Botswana. The annual cycle occurred in three distinct periods. The swarming season occurred from October-November, following two to three months of intense brood production, and coincided with the end of peak forage abundance. The migration season occurred from November-May and coincided with reduced and variable floral resources. During the migration season, brood production and food storage were generally low but quite variable from month to month, and swarms passing over the study area at this time traveled in an easterly direction. The migration season was followed by the establishment period (June-September), in which large numbers of new colonies traveling from the west moved into the study area. The establishment period coincided with, and slightly preceded, the period of peak forage abundance, and colonies devoted resources collected at this time almost entirely to brood rearing, which culminated in swarm production. The data suggest that honey bee colonies in the Okavango are mobile and gear their reproduction and movement to seasonally shifting resource pattern.

Seasonal patterns of foraging activity in colonies of the African honey bee,Apis mellifera scutellata, in Africa

Seasonal foraging patterns were investigated using six observation colonies maintained in the Okavango Delta, Botswana. Pollen collection, flight from the hive, and recruitment for pollen and nectar sources occurred throughout the 11 months of the study. However, the distribution of foraging activity throughout the day changed seasonally. Colonies emphasized recruitment for pollen sites throughout most of the year. Brood production occurred in all months except May, and there was a significant, positive correlation between the proportion of recruitment activity devoted to pollen sources and the amount of brood comb in the colonies. The seasonal foraging patterns ofscutellata in the Okavango were similar to those of Africanized honey bees in the neotropics. The extended foraging season and emphasis on pollen collection may be associated with the high swarming rates and migrational movements of tropical honey bees.

The Biology and Management of Africanized Honey Bees

The introduction of African honey bees (Apis mellifera scutellata) to South America in 1956 resulted in one of the most astounding success stories in the history of introduced insect species. The descendants of these bees have spread at an unprecedented speed, and their populations have grown rapidly to high densities throughout their range. Further, Africanized honey bees (which is the name most commonly used to refer to them in the Americas) have had enormous impact on beekeeping and the public, and have generated countless radio, newspaper, and television stories. Indeed, this insect has become such a significant media star that it has been granted its own nickname, the Killer Bee. Today, these bees have spread through most of South America and all of Central America, and have recently entered the United States from Mexico. Predictions of their impact are serious, and include disruptions of both beekeeping and the production of bee-pollinated crops. The threat from these bees was recognized soon after their introduction and stimulated an enormous amount of research into their biology and potential management and control. What has emerged from these studies is a picture of a bee ideally pre-adapted to its new habitat and impervious (so far) to any proposed or attempted barrier to its spread. This review describes some of the reasons behind the un­ paralleled success of this unusual insect, discusses its impact in Latin Amer-

African bees in the Americas: Insights from biogeography and genetics

The spread of African honey bees in South and Central America is one of the most remarkable and certainly among the most highly publicized instances of biological invasion. Their aggressive nest defense has led to numerous stinging incidents and even deaths; aggressiveness, coupled with a tendency to abandon the nest when disturbed, has also caused serious disruption of beekeeping and pollination industries in regions that they have invaded. The rapid spread of African bees in the Americas and their recent arrival in the United States have sparked interest in development of genetic tools for identification of honeybee populations. This in turn has renewed interest in honeybee biogeography.

Use of drone trapping and drone releases to influence matings of European queens in an Africanized honey bee area (Hymenoptera: Apidae)

SUMMARYA series of releases of virgin European honey bee (Apis mellifera) queens was made in a 4-km2 area dominated by African honey bees (AHB) near Ciudad Hidalgo, Chiapas, Mexico, in November-December, 1989. Queens were allowed to mate before and after experimental manipulations of the local drone population. After the first series of queen matings, aerial drone traps were used to capture and eliminate 6 398 drones. Then, approximately 6 400 drones of known colour (yellow) from managed European colonies were introduced into the area via drone source colonies, and a second series of queen matings was done. The drones caught in aerial traps were colour sorted. Essentially, 80% of the drones during the first mating period were black (MDH allelic frequencies typical of feral Africanized bees). During the second mating period, the percentage of black drones was much lower, averaging 53%. The drone population manipulations resulted in a significant increase (from 47.4% before to 93.6% after) in the proportion...

Nest characteristics and recruitment behavior of absconding colonies of the African honey bee,Apis mellifera scutellata, in Africa

Absconding behavior was investigated in a naturally occurring population of honey bees in the Okavango River Delta, Botswana. Fifty percent of all colonies excavated in the field between October and December had abandoned the nest or were preparing for absconding, suggesting that an “absconding season” began in the Delta in October or November. However, the factors influencing absconding during this period were unclear, and there were no distinct differences in nest characteristics of the absconding and nonabsconding colonies. Waggle dance activity in observation colonies preparing for absconding was not used to preselect a specific nest site prior to departure. However, in two of the three colonies examined recruitment activity indicated the general direction of colony travel. The distances indicated by these dancers ranged between 6 and 16 km. Since these distances were three to four times greater than those communicated by dancers in nonabsconding colonies, workers from absconding colonies may sample potential forage or nest sites well outside their regular foraging range.

Spatial foraging patterns of the African honey bee,Apis mellifera scutellata

Recruitment patterns were investigated for the African honey bee in the Okavango River Delta, Botswana. The waggle dances of two observation colonies maintained in the field were monitored and used to construct maps of daily recruitment activity. These maps revealed that the African colonies frequently adjusted the allocation of recruits among food patches, recruited for 16–17 different food sites/day over areas of 55–80 km 2 ,and concentrated the majority of recruitment within 1 km of the hives (median foraging distances for the two colonies were 295 and 563 m). In both colonies pollen foragers were more abundant than nectar foragers, and pollen sources indicated by waggle dancers were significantly closer to the hives than nectar sources. Compared to the recruitment patterns of temperate climate colonies, the African colonies had smaller recruitment areas, smaller mean recruitment distances, and a greater emphasis on pollen foraging. These differences may be related to the contrasting survival strategies followed by tropical-versus temperate-climate honey bees.

Neotropical Africanized honey bees have African mitochondrial DNA

Non-indigenous African honey bees have invaded most of South and Central America in just over 30 years. The genetic composition of this population and the means by which it rapidly colonizes new territory remain controversial. In particular, it has been unclear whether this 'Africanized' population has resulted from interbreeding between African and domestic European bees, or is an essentially pure African population. Also, it has not been known whether this population expanded primarily by female or by male migration. Restriction site mapping of 62 mitochondrial DNAs of African bees from Brazil, Venezuela and Mexico reveals that 97% were of African (Apis mellifera scutellata) type. Although neotropical European apiary populations are rapidly Africanized by mating with neotropical African males, there is little reciprocal gene flow to the neotropical African population through European females. These are the first genetic data to indicate that the neotropical African population could be expanding its range by female migration.

Evidence from mitochondrial DNA that African honey bees spread as continuous maternal lineages

African honey bees have populated much of South and Central America and will soon enter the United States. The mechanism by which they have spread is controversial. Africanization may be largely the result of paternal gene flow into extant European populations or, alternatively, of maternal migration of feral swarms that have maintained an African genetic integrity. We have been using both mitochondrial and nuclear DNA restriction fragment length polymorphisms to follow the population dynamics between European and African bees. In earlier reports, we suggested that if African honey bees had distinctive mitochondrial (mt) DNA, then it could potentially distinguish the relative contributions of swarming and mating to the Africanization process. Because mtDNA is maternally inherited, it would not be transmitted by mating drones and only transported by queens accompanying swarms. Furthermore, the presence of African mtDNA would reflect unbroken maternal lineages from the original bees introduced from Africa. The value of mtDNA for population studies in general has been reviewed recently. Here we report that 19 feral swarms, randomly caught in Mexico, all carried African mtDNA. Thus, the migrating force of the African honey bee in the American tropics consists of continuous African maternal lineages spreading as swarms. The mating of African drones to European queens seems to contribute little to African bee migration.

The pollination ecology of Aloe ferox Mill.

The breeding system and pollination ecology of Aloe ferox Mill. were investigated. The relationship between plant height, raceme number, raceme length and percentage fruit success was determined for 93 plants. There was a significant positive relationship between plant height and raceme number but the percentage fruit success did not increase with an increase in plant height, number of racemes and mean and total raceme length. A description of post-anthesis flower development is given. Optimal stigma receptivity occurs 8 to 24 h after anthesis and is synchronized with maximum nectar concentration and volume. The flower morphology of this species suggests a bird- pollinated syndrome. This study shows, however, that African honey bees may also play a role in its pollination. Bees visit the anthers as soon as they are exerted beyond the floral tube and, because the stigmas are at least partially receptive at this early post-anthesis stage, fertilization can be affected. This species is self-incompatible and selection pressures have probably been to minimize the number of flowers open on an inflorescence at any one time.

The habitat and nesting biology of the African honey beeApis mellifera scutellata in the Okavango River Delta, Botswana, Africa

The habitat and nesting biology were studied for naturally occurring colonies of the African honey bee,Apis mellifera scutellata, in the Okavango River Delta, Botswana. Vegetational surveys revealed that the forage available to Delta colonies was abundant and potentially available year round. Colonies had a density of 7.8 nests/km2. Nest cavities occurred with equal frequency in trees and termite mounds, had a volume of approximately 17 L, were unpropolized, and had south-facing, top-located entrances. Delta colonies were small (ca. 6,500 workers), constructed small amounts of comb (ca. 3,000 cm2), stored little food, devoted 78% of comb space to brood production, exhibited little nest defense, and experienced a 48% predation rate during the 5 month study period. The characteristics observed forscutellata in this study are discussed as adaptations to the hot climate, long foraging season, and high predation rate experienced in the Delta. Data for the Delta colonies are compared to those forscutellata in other tropical areas, and to honey bees in temperate climate regions.

Sporadic food competition with the African honey bee: projected impact on neotropical social bees

ABSTRACTBee colonies in lowland forest in Panama were monitored for pollen and nectar harvest, pollen species utilization and nectar quality and quantity per returning forager. Despite sharing most pollen resources and nectar of the same quality with 20 introduced colonies of the African honey bee (Apis mellifera), native stingless bees of 12 species were largely unaffected by its activity. Pollen and nectar harvested by the honey bees were 10–200 times that procured by 17 stingless bee colonies. This discrepancy in total harvest and general lack of competitive effect is explained by a honey bee foraging area over 10 times that of the native bees, and apparent foraging shifts to escape competition with honey bees, thus reduced potential overlap in foraging sites.Seven cases of direct resource competition for pollen or nectar were documented, out of 31 tests. Rare periods of intensive harvest were diminished by competing African honey bees. Such harvest peaks lasted for only a few hours in 13 days of observation. Despite average duration of 4% foraging time for each species, peaks included as much as 51% total harvest. Calculations based upon colony populations, food stores and flight range show that if African honey bees persist at a density of 1 colony per km2, colonies of some stingless bee species may disappear after 10 years. Their chances of escaping food competition by taxonomic specialization on flowers seem slight.

Nocturnal Bee Abundance and Seasonal Bee Activity in a Panamanian Forest

Bees were monitored weekly for 7 yr at light traps in the tropical monsoon forest of Barro Colorado Island. Fifty species and 17 genera were recorded, including nocturnal Megalopta and crepuscular Rhinetula (Halictidae) and Ptiloglossa (Colletidae). Twenty—eight native meliponines and African Apis mellifera in traps increased the known resident highly social bees to 32 species. Most of the 11,860 bees were Megalopta; these species were present throughout the year, as were Rhinetula and Ptiloglossa. Abundance of Megalopta was lowest during the dry season; this was its only consistent seasonality. Peak abundance occurred at various times during dry—to—wet—season transition and in the first half and the end of the wet season. Centris and Epicharis, large, solitary anthrophorid bees, were present in the early wet season and absent in the late wet season and most of the dry season. The highly social bee Trigona aff. cupira was aseasonal but had abundance peaks during all but the mid—to—late wet season. Megalopta genalis abundance and M. ecuadoria abundance were highly positively correlated within years, and weekly correlated with abundances of other bees. Pairwise correlations between years were low for each Megalopta species and for combined bees of other genera. A singularly large catch of Megalopta genalis in 1978 corresponded to flowering of the monocarpic tree Tachigalia versicolor near light traps. Fluctuation of bee abundance at light traps probably indicates local flower availability for this species and, to a lesser extent, for the other bees. The data suggest large year—to—year variation in seasonal abundance of resources used by nocturnal bees and by bees in general, but are limited to indicating the presence or absence of most other bee species. The yearly variances in abundance of a stingless bee species and of Megalopta in Panama are comparable to those of eight temperate bumble bee species studied in England, but combined diurnal and crepuscular bee abundance is considerably less variable. The African honey bee arrived on Barro Colorado Island in mid—1982 and has produced no noticeable changes in abundance of other bees but has yet to reach its potential, numbers there; light—trap studies could provide perhaps the most reliable information on its impact.

Comparative Toxicities of Four Topically Applied Insecticides to Africanized and European Honey Bees (Hymenoptera: Apidae)

Contact toxicities were established for acetone formulations of azinphosmethyl, carbaryl, methyl parathion, and permethrin applied to workers of Africanized and European honey bee (Apis mellifera L.) types. For each insecticide, 95% fiducial limits at the LC50 levels for the two bee types did not overlap. Africanized bees showed greater tolerance to all the chemicals except carbaryl; differences in tolerance to each of the four chemicals were all about 2-fold. The order of toxicity of the compounds on the Africanized bees was permethrin > carbaryl > azinphosmethyl > methyl parathion; on the European honey bees, the order of toxicity was permethrin > azinphosmethyl > carbaryl> methyl parathion. Significant differences between the bee types were noted in the slopes of the probit regressions estimated for three of the compounds. The Africanized bees responded more homogeneously than the European bees to azinphosmethyl; European bees reacted more homogeneously than Africanized bees to carbaryl and permethrin.

Animal and Plant Health Inspection Service Strategy and the African Honey Bee

The African honey bee (AHB), often depicted by the media as the killer bee, is the literal stuff of science fiction and horror stories. It is an apparently mythological creature featured in stories, articles, and movies as a sort of super bee—and a terrifying killer for which futuristic solutions are developed (for interesting reading, see Killer Bees by Anthony Potter, 1977, Grosset and Dunlap, New York).

Experimental Community Studies: Time‐Series Tests of Competition between African and Neotropical Bees

Experimental studies of food competition were performed in lowland forest of French Guiana by controlled introduction and removal of a small number of African honey bee colonies, totaling 100 000—150 000 bees. Trends in brood production and food storage by observations colonies of native social bees, Melipona favosa and M. fulva, were described with linear stochastic statistical models. Data were taken after the introduction of honey bee colonies, and the models were used to construct falsifiable hypotheses that would suggest whether the honey bees disrupted colony growth and resource harvest of native species. During a 1—mo introduction of honey bees in the wet season, when floral resources were at low abundance, time—series intervention analyses showed that African Apis had no significant effect on native bee colonies. Repeated—measures ANOVA also showed no treatment effect on bee colonies, and removal of 5—10 honey bee colonies had no effect on brood dynamics and food storage of four conspecific colonies. All colonies foraged during experiments, yet no competition was recorded. Since the three species are diet generalists and share many of the same resources, competition at flowers was not disproved, although any cumulative effects were negligible. Linear, stochastic integrated autoregression/moving average (ARIMA) models were useful in removing statistical dependence in data series and allowing hypothesis tests, but intracolony variables showed seasonal decline that prevented introduction of deterministic components that would have improved some models. Perturbation of social tropical bee communities by colonizing African Apis is unlikely to become evident within a short time or at relatively low honey bee colony density.

Longevity of Africanized Honey Bees (Hymenoptera: Apidae) Infested by Varroa jacobsoni (Parasitiformes: Varroidae)

The longevity of normal and varroa-infested Africanized honey bees, Apis mellifera L., was compared. The degree of infestation was determined by counting the adult and deutonymphal female mites present in the brood cell when the adult bee emerged. Uninfested control bees lived an average of 27.6 days; infested bees lived only 13.6. Bees infested with two or more mites lived 8.9 days. The number of mites per bee was significantly negatively correlated with both longevity and weight at emergence. There was no significant correlation between weight at emergence and longevity for infested or uninfested bees. Reduction in longevity appears not to be merely a secondary result of reduced adult weight.

Night‐time sun‐compass behaviour of honey bees at the equator

ABSTRACT. In accordance with the peculiarities of the sun's azimuthal path near the equator, African honey bees observed in their night‐time dances apparently allowed for the azimuth moving backwards at night relative to its day‐time movement. In several cases the bees evidently inferred the actual azimuthal position of the sun, rather than the one that would result from extrapolating a uniform movement of the sun.

Competitive Interactions Between Neotropical Pollinators and Africanized Honey Bees

The Africanized honey bee, a hybrid of European and African honey bees, is thought to displace native pollinators. After experimental introduction of Africanized honey bee hives near flowers, stingless bees became less abundant or harvested-less resource as visitation by Africanized honey bees increased. Shifts in resource use caused by colonizing Africanized honey bees may lead to population decline of Neotropical pollinators.

The Brazilian bee problem.

There have been repeated and sometimes lurid references to the introduction of African honey bees into South America, to the spread of such bees or their hybrid descendants (Africanized bees, i.e. the Brazilian honey bee), and to the influence of such bees on apiculture, pollination, animal husbandry, and public health in South America and, prospectively, in North America. Much of what is known about these bees in South America appears in the Final Report of the Committee on the African Honey Bee (27) and in two subsequently annotated versions of the same report (31). One function of the present review is to place some of the content of these reports in more accessible form. Another is to review the numerous more recent contribu­ tions on the subject, largely from Brazilian sources (including references 13, and 14; proof sheets of only a few articles in reference 13 were available when reference 27 was prepared). Emphasis is placed on the history, present status, and principal attributes of these bees. An account of their possible impact in North America is given in the first report mentioned (27). Some of the questions about these bees have so far been answered from reports of beekeepers, rather than by controlled experiments or observations. Because of variability of the population over a vast area, the results of experiments even where they have been carried out may not be applicable everywhere. Sources of informa­ tion are therefore documented below. The code B indicates information from bee­ keepers, including anecdotal information from scientists. SP refers to observations or experiments made on the population of bees of the central part of the state of Sao Paulo (Piricicaba, Rio Claro, Ribeirao Preto, etc), where most of the experimen­ tal work has been done; in effect, it means under the conditions of central Sao Paulo.