David De Jong

Identification of Africanized honey bees through wing morphometrics: two fast and efficient procedures*

Currently available morphometric and genetic techniques that can accurately identify Africanized honey bees are both costly and time consuming. We tested two new morphometric techniques (ABIS — Automatic Bee Identification System and geometric morphometrics analysis) on samples consisting of digital images of five worker forewings per colony. These were collected from 394 colonies of Africanized bees from all over Brazil and from colonies of African bees, Apis mellifera scutellata (n = 14), and European bees, A. m. ligustica (n = 10), A. m. mellifera (n = 15), and A. m. carnica (n=15) from the Ruttner collection in Oberursel, Germany (preserved specimens). Both methods required less than five minutes per sample, giving more than 99% correct identifications. There was just one misidentification (based on geometric morphometrics analysis) of Africanized bees compared with European subspecies, which would be the principal concern in newly-colonized areas, such as the southern USA. These new techniques are inexpensive, fast and precise.ZusammenfassungDie Afrikanisierten Honigbienen sind unter den verschiedenen Unterarten und Rassengruppen der Honigbiene (Apis mellifera L.) in den Neotropen und den Nachbarregionen am meisten respektiert und gefürchtet, insbesondere da sie in neue Gebiete einwandern. Die Identifizierung der Afrikanisierten Bienen ist in diesen Regionen für die Bewirtschaftung der Bienenvölker daher unverzichtbar. Sie ermöglicht die Bestimmung ihres Verbreitungsgebiets und ihrer Ausbreitungsgeschwindigkeit, dies ist sowohl für die Imker als auch für die damit befassten Regierungseinrichtungen von Bedeutung.Wir benutzten zwei kürzlich entwickelte morphometrische Techniken (ABIS — Automatic Bee Identification System und die Geometrische Morphometrische Analyse), um Proben aus jeweils fünf rechten Vörderflügeln pro Volk zu analysieren (Tab. I). Beide dieser Methoden benötigten in einem Vergleich von 394 über ganz Brasilien verteilten Völkern weniger als 5 Minuten pro Volk und erreichten eine mehr als 99% korrekte Identifizierung. Diese ergaben 14 Völker von A. m. scutellata, 10 Völker von A. m. ligustica, 15 Völker von A. m. mellifera und 15 Völker von A. m. carnica (Tab. II und III). Mit ABIS können einzelne Bienen bestimmt werden, während die Geometrische Morphometrische Analyse eine auf jeweils 5 Flügeln beruhende Identifikationen auf Kolonieebene durchführt. Die meisten der Fehleinordnungen fanden zwischen Afrikanisierten und Afrikanischen Bienen sowie zwischen den europäischen Unterarten statt. Nur eines der Afrikanisierten Bienenvölker wurde irrtümlich als eine europäische Unterart eingeordnet, dies ist die Fehlerart die insbesondere innerhalb von neubesiedelten Gebieten wie den Südstaaten der USA von Bedeutung wäre. Die erreichten Fortschritte in Computertechnologie, statistischen Analysen und Bilderkennungssoftware sowie die verbesserten Informationen über die relevanten Messgrößenbereiche und die höhere Genauigkeit und größere Geschwindigkeit der Messungen selbst machen es nun möglich, Afrikanisierte Bienen ausschließlich anhand von Digitalaufnahmen der Vörderflügel in Minutenschnelle zu identifizieren.

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

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.

Africanized honey bees in Brazil, forty years of adaptation and success

On this 40th ‘anniversary’ of Africanized honey bees in the Americas, David De Jong, a prominent bee researcher who has worked for many years on AHB, gives his personal views and puts the problems faced by beekeepers in Brazil into perspective. Here, he reviews how beekeeping practice has changed as beekeepers have successfully adapted to managing these behaviourally problematic bees.

The Seasonal Cycle of Swarming in Honeybees

SummaryA six-year study of natural swarming in Ithaca, NY, USA, showed a bimodal distribution for date of swarm emergence, with a peak during the first two weeks in June and a lesser peak during the last week in August and the first week in September. The mean swarm size for 126 swarms was 1·53 kg (11 800 bees). The mean weight of 116 swarm queens was 195·9 mg; of mated queens 203·4 mg, and of virgin queens 185·0 mg. Data from 1976 suggest that a virgin or a young mated queen may accompany a prime swarm.

Pollen substitutes increase honey bee haemolymph protein levels as much as or more than does pollen.

Summary Adequate substitutes for pollen are necessary for maintaining healthy bee colonies during periods of pollen dearth, but testing them objectively is both time consuming and expensive. We compared two commercial diets with bee collected pollen and acacia pod flour (used by beekeepers in some parts of Brazil) by measuring their effect on haemolymph protein contents of young bees exclusively fed on these diets, which is a fast and inexpensive assay. The commercial diets included a new, non-soy-based, pollen substitute diet (named Feed-Bee®) and a soy-based diet, named Bee-Pro®. The diets were each given in patty form to groups of 100 Africanized honey bees in hoarding cages, maintained and fed from emergence until six days of age. Sucrose, in the form of sugar syrup, was used as a protein free control. Feed-Bee®, Bee-Pro®, pollen and acacia pod flour diets increased protein titers in the haemolymph by factors of 2.65, 2.51, 1.76 and 1.69, respectively, over protein titers in bees fed only sucrose solution. The bees fed Feed-Bee® and Bee-Pro® had their haemolymph significantly enriched in protein compared to the controls and those fed acacia pod flour and to titers slightly higher than those fed pollen. All four proteinaceous diets were significantly superior to sucrose alone.

Fipronil and imidacloprid reduce honeybee mitochondrial activity

Bees have a crucial role in pollination; therefore, it is important to determine the causes of their recent decline. Fipronil and imidacloprid are insecticides used worldwide to eliminate or control insect pests. Because they are broad-spectrum insecticides, they can also affect honeybees. Many researchers have studied the lethal and sublethal effects of these and other insecticides on honeybees, and some of these studies have demonstrated a correlation between the insecticides and colony collapse disorder in bees. The authors investigated the effects of fipronil and imidacloprid on the bioenergetic functioning of mitochondria isolated from the heads and thoraces of Africanized honeybees. Fipronil caused dose-dependent inhibition of adenosine 5-diphosphate-stimulated (state 3) respiration in mitochondria energized by either pyruvate or succinate, albeit with different potentials, in thoracic mitochondria; inhibition was strongest when respiring with complex I substrate. Fipronil affected adenosine 5-triphosphate (ATP) production in a dose-dependent manner in both tissues and substrates, though with different sensitivities. Imidacloprid also affected state-3 respiration in both the thorax and head, being more potent in head pyruvate-energized mitochondria; it also inhibited ATP production. Fipronil and imidacloprid had no effect on mitochondrial state-4 respiration. The authors concluded that fipronil and imidacloprid are inhibitors of mitochondrial bioenergetics, resulting in depleted ATP. This action can explain the toxicity of these compounds to honeybees.

Nectar and pollen production in pumpkin (Cucurbita pepo L.)

As especies das cucurbitaceas dependem da polinizacao por abelhas para produzir frutos. O objetivo geral deste trabalho foi avaliar o potencial da C. Pepo para produzir polen e nectar, no sentido de ajudar a manter colonias no campo visando a polinizacao. Plantas de abobora foram cultivadas no campo, em 1996 e 1997. Antes da antese, flores masculinas foram cobertas para prevenir visitas de abelhas e outros insetos. Depois da antese as flores foram desprotegidas e os seguintes parâmetros foram avaliados: 1) producao de nectar; 2) concentracao total de acucar no nectar; 3) reposicao de nectar e 4) producao de polen e flores durante o ciclo da cultura. A producao de nectar variou de 18 a 79 µL flor-1 e aumentou progressivamente de 7h00 para 13h00. A concentracao de acucares, avaliada as 7h00, 9h00 e 11h00, nao variou, apresentando uma media de 50,5% ± 0,5% em 1996 e 40,5% ± 0,6% em 1997. As 13h00 a concentracao decresceu para 42% em 1996 e para 35% em 1997. A producao diaria de nectar nao foi influenciada pela remocao do nectar em diferentes horas do dia, indicando que a producao de nectar nao e estimulada ou inibida pela frequente remocao. O numero de graos de polen nao variou nos dois anos, com uma media de 43.669 ± 1.382 graos por flor. O pico de producao de flores masculinas e femininas ocorreu 60 a 66 dias apos o plantio (DAP), com 34,6 flores masculinas e 2,2 flores femininas por planta, respecivamente. C. pepo tem um potencial para producao de mel e polen de 105 e 160 kg por hectare, respectivamente, que e suficiente para alimentar, pelo menos, cinco colonias de abelhas.

Increased brood viability and longer lifespan of honeybees selected for propolis production

Propolis has been proposed to affect honeybee health. To test this hypothesis, we initially evaluated propolis production in 36 honeybee colonies. The three highest (HP) and three lowest propolis-producing (LP) colonies had mean yields of 16.0 and 0.64xa0g, respectively. Queens and drones from these parental colonies were crossed by artificial insemination to produce five colonies each of the following crosses: HP♀u2009×u2009HP♂, HP♀u2009×u2009LP♂, LP♀u2009×u2009HP♂, and LP♀u2009×u2009LP♂. Colonies headed by HP♀u2009×u2009HP♂ queens produced 34 times more propolis than those headed by LP♀u2009×u2009LP♂ queens and five times more than those from the other two crosses. Newly emerged bees were marked to measure longevity, and egg and brood counts were made to determine brood survival rates. The colonies with queens derived from crosses between high-propolis-producing colonies had significantly higher brood viability and greater worker bee longevity. We conclude that colonies that collect more propolis are healthier and have longer-living bees.

Honey bee lines selected for high propolis production also have superior hygienic behavior and increased honey and pollen stores

Honey bees use propolis to defend against invaders and disease organisms. As some colonies produce much more propolis than others, we investigated whether propolis collecting is associated with disease resistance traits, including hygienic behavior and resistance to the parasitic bee mite, Varroa destructor. The three highest (HP) and three lowest propolis-producing (LP) colonies among 36 Africanized honey bee colonies were initially selected. Queens and drones from these colonies were crossed through artificial insemination to produce five colonies of each of the following crosses: HP♀ X HP♂, LP♀ X HP♂, HP♀ X LP♂, and LP♀ X LP♂. Colonies headed by HP♀ X HP♂ queens produced significantly more propolis than those with HP♀ X LP♂ and LP♀ X HP♂ queens and these in turn produced significantly more propolis than those headed by LP♀ X LP♂ queens. The brood cell uncapping rate of the high-propolis-producing colonies in the hygienic behavior test was significantly superior to that of the other groups. The LP X LP group was significantly less hygienic than the two HP X LP crosses, based on the evaluation of the rate of removal of pin-killed pupae. The HP X HP colonies were significantly more hygienic than the other crosses. No significant differences were found in mite infestation rates among the groups of colonies; although overall, colony infestation rates were quite low (1.0 to 3.2 mites per 100 brood cells), which could have masked such effects. Honey and pollen stores were significantly and positively correlated with propolis production.

HONEY BEE AS AN EFFECTIVE POLLINATING AGENT OF PUMPKIN

The production of fruits and seeds of many crops is increased when bees visit their flowers pollinating them. The aim of this research was to study the pollination of pumpkins (Cucurbita maxima Duch. var. Exposicao), to determine the diversity of insects visiting its flowers, the time and type of provision obtained and the effect of the visits on fruit set, fruit size and weight, and number of seeds. Apis mellifera L. accounted for 73.4% of the visits made by bees, collecting pollen during 34.5 s per flower and nectar in 43.9 s and 29.3 s from female and male flowers, respectively. Trigona spinipes (Fabr.) collected only nectar, during a mean time of 60.5 s per flower, and represented 26.6% of the visits by bees. Diabrotica speciosa (Germ.) only fed on the petals of the flower. When no insect visits occurred, there was no production of fruits. In the flowers with free visitation by insects, fruit set was 40%. The higher the number of visits, up to 16, by A. mellifera to female flowers, the greater was the fruit set, fruit size and weight, and number of seeds. In flowers visited by insects from the onset of anthesis until 9 a.m., fruit set was 35%. After 9 a.m., there was no fruit set, demonstrating the important role of A. mellifera as a pollinating agent of pumpkin, since it was the only insect visiting up to 9 a.m.