Limited impacts of truck-based ultra-low-volume applications of mosquito adulticides on mortality in honey bees (Apis mellifera).

Adulticides applied against mosquitoes can reduce vector populations during times of high arbovirus transmission. However, impacts of these insecticides on pollinators and other non-target organisms are of concern to mosquito control professionals, beekeepers and others. We evaluated mortality of Culex quinquefasciatus and Apis mellifera when caged insects were exposed to low and high label rates of four common adulticides (Aqua-Pursuit™ [permethrin], Duet® [prallethrin + sumithrin], Fyfanon® [malathion] and Scourge® [resmethrin]) at six distances up to 91.4 m from a truck-mounted ultra-low-volume sprayer. Honey bee mortality was both absolutely low (61 m had limited impacts on honey bee mortality while providing effective mosquito control.

Inheritance of thelytoky in the honey bee Apis mellifera capensis.

Asexual reproduction via thelytokous parthenogenesis is widespread in the Hymenoptera, but its genetic underpinnings have been described only twice. In the wasp Lysiphlebus fabarum and the Cape honey bee Apis mellifera capensis the origin of thelytoky have each been traced to a single recessive locus. In the Cape honey bee it has been argued that thelytoky (th) controls the thelytoky phenotype and that a deletion of 9 bp in the flanking intron downstream of exon 5 (tae) of the gemini gene switches parthenogenesis from arrhenotoky to thelytoky. To further explore the mode of inheritance of thelytoky, we generated reciprocal backcrosses between thelytokous A. m. capensis and the arrhenotokous A. m. scutellata. Ten genetic markers were used to identify 108 thelytokously produced offspring and 225 arrhenotokously produced offspring from 14 colonies. Patterns of appearance of thelytokous parthenogenesis were inconsistent with a single locus, either th or tae, controlling thelytoky. We further show that the 9 bp deletion is present in the arrhenotokous A. m. scutellata population in South Africa, in A. m. intermissa in Morocco and in Africanized bees from Brazil and Texas, USA, where thelytoky has not been reported. Thus the 9 p deletion cannot be the cause of thelytoky. Further, we found two novel tae alleles. One contains the previously described 9 bp deletion and an additional deletion of 7 bp nearby. The second carries a single base insertion with respect to the wild type. Our data are consistent with the putative th locus increasing reproductive capacity.

Male reproductive parasitism: a factor in the africanization of European honey-bee populations.

Africanized drone honey bees (Apis mellifera) migrate into European honey-bee colonies in large numbers, but Africanized colonies only rarely host drones from other colonies. This migration leads to a strong mating advantage for Africanized bees since it both inhibits European drone production and enhances Africanized drone production.

Colony defense by africanized and European honey bees.

Africanized and European honey bee (Apis mellifera) populations showed quantitative differences in colony defensive behavior. Africanized bees responded faster and in much larger numbers than European honey bees and produced 8.2 and 5.9 times as many stings during two different experiments. Times to react to alarming stimuli were negatively correlated with the number of bees responding and to the total number of stings. The number of bees responding was significantly correlated to the total number of stings only for the Africanized population.

Hybridization between European and africanized honey bees in the neotropical yucatan peninsula.

A population genetic analysis of honey bees of the Mexican neotropical Yucatan peninsula shows that the range expansion of Africanized bees there has involved extensive introgressive hybridization with European bees. Yucatan honey bee populations now include many colonies with intermediate morphologies. Genotypes of mitochondria have disassociated from historically correlated Africanized or European morphology, producing diverse phenotypic associations. This suggests that the size of resident European populations may be important in explaining previously reported asymmetrical hybridization. Evidence of natural hybridization is encouraging for the use of genetic management to mitigate the effects of Africanized bees in the United States.

Sociochemical alteration of honeybee hoarding behavior.

Hoarding experiments were conducted with honeybees (Apis mellifera L.) in cages containing comb treated with either 2-heptanone, isopentyl acetate, citral, or geraniol. 2-Heptanone increased hoarding rates; isopentyl acetate decreased hoarding rates; citral and geraniol had no observed effect.

Effect of empty comb on defensive behavior of honeybees.

Honeybees in colonies with 6.36-m(2) surface area of empty comb responded faster to moving targets and stung the targets more often than bees from colonies with 3.18-m(2) surface area of empty honeycomb. The two groups did not differ significantly in speed of response to alarm pheromone or in number of bees defending the colony. Volatiles from the comb are suggested as primer pheromones for defensive behavior.

Genic control of honey bee dance language dialect.

Behavioural genetic analysis of honey bee dance language shows simple Mendelian genic control over certain dance dialect differences. Worker honey bees of one parent colony (yellow) changed from round to transition dances for foraging distances of 20 m and from transition to waggle dances at 40 m. Worker bees of the other parent colony (black) made these shifts at 30 m and 90 m, respectively. F1 colonies behaved identically to their yellow parent, suggesting dominance. Progeny of backcrossing between the F1 generation and the putative recessive black parent assorted to four classes, indicating that the dialect differences studied are regulated by genes at two unlinked loci, each having two alleles. Honey bee dance communication is complex and highly integrated behaviour. Nonetheless, analysis of a small element of this behaviour, variation in response to distance, suggests that dance communication is regulated by subsets consisting of simple genic systems.

DNA evidence of the origin of Varroa jacobsoni Oudemans in the Americas.

Randomly amplified polymorphic DNA (RAPD) was used to examine possible origin of Varroa jacobsoni Oudemans in the Americas. Among 64 primers screened, 2 primers provided variation which was informative for this study. All V. jacobsoni collected from the United States had the same banding pattern to that of mites collected from Russia, Morocco, Germany, Italy, Spain, and Portugal (Russian pattern). This banding pattern was different from the pattern found for mites collected from Japan, Brazil, and Puerto Rico (Japanese pattern). The Japanese pattern lacked a 766-bp band found in the Russian pattern (OPE-07). With primer OPP-03, the Russian pattern had a distinct band at 442 bp not found in the Japanese pattern. Two bands located at 675 and 412 bp were specific to the Japanese pattern. These results suggest that the V. jacobsoni of the United States is probably predominantly Russian in origin (via Europe), while the V. jacobsoni of Brazil and Puerto Rico are probably predominantly Japanese in origin.

Origin of honeybees (Apis mellifera L.) from the Yucatan peninsula inferred from mitochondrial DNA analysis.

Honeybees (Apis mellifera L.) sampled at sites in Europe, Africa and South America were analysed using a mitochondrial DNA restriction fragment length polymorphism (RFLP) marker. These samples were used to provide baseline information for a detailed analysis of the process of Africanization of bees from the neotropical Yucatan peninsula of Mexico. Radical changes in mitochondrial haplotype (mitotype) frequencies were found to have occurred in the 13-year period studied. Prior to the arrival of Africanized bees (1986) the original inhabitants of the Yucatan peninsula appear to have been essentially of southeastern European origin with a smaller proportion having northwestern European ancestry. Three years after the migration of Africanized bees into the area (1989), only very low levels of maternal gene flow from Africanized populations into the resident European populations had occurred. By 1998, however, there was a sizeable increase in the proportion of African mitotypes in domestic populations (61%) with feral populations having 87% of mitotypes classified as African derived. The results suggest that the early stages of Africanization did not involve a rapid replacement of European with African mitotypes and that earlier studies probably overestimated the prevalence of African mitotypes.

Alarm pheromone production by two honeybee (Apis mellifera) types.

Of 12 alarm pheromones assayed in European and Africanized honeybees, nine were found in larger quantities in the Africanized population. Isopentyl and 2-heptanone levels were similar in both; 2-methylbutanol-1 was greater in European workers. These differences were not due to age or geographical location. Significant positive correlations between alarm pheromone levels and defensive behavior, especially numbers of stings, were observed.

Oxygenated compounds in beeswax: identification and possible significance.

1. Beeswax synthesized by non-foraging honeybee workers contains six oxygenated volatiles in addition to a series of normal alkanes. 2. Decanal constitutes nearly 50% of the oxygenated volatiles and is accompanied by octanal, nonanal, furfural, benzaldehyde and 1-decanol. 3. The possible significance of the aldehydes as stimulators of hoarding behaviour and attractants for wax moths is discussed.

Chemistry of cephalic secretion of fire beeTrigona (Oxytrigona) tataira.

Analysis of the volatile compounds derived from cephalic glands of the fire beeTrigona (Oxytrigona) tataira by GC-MS was undertaken. The following compounds were readily identified: hydrocarbons:n-C11H24,n-C13H28,n-C14H30,n-C15H32,n-C17H36,n-C23H48,n-C15H30,n-C17H34,n-C21 H42, andn-C23H46; carboxylic acids: palmitic acid, linoleic acid, linolenic acid, stearic acid, and oleic acid; carboxylic esters: dodecyl acetate, tetradecyl acetate, hexadecyl acetate, octadecyl acetate, and dodecyl decanoate; monoketones: 5-hepten-2-one, 3-hepten-2-one, 2-heptanone, and 5-nonen-2-one. Two major components of the mixture were identified asE-hepten-2,5-dione andE-3-nonen-2,5-dione. Structures of these novel compounds were suggested by their GC-MS behavior and the GC-MS behavior of their dimethoximes and proved by comparison with authentic synthetic samples. Trace amounts of the corresponding Z isomers and the saturated analogs, heptan-2,5-dione and nonan-2,5-dione, were also found. The possible functions of these glandular constituents are discussed.

Nest plundering allomones of the fire beeTrigona (Oxytrigona) mellicolor.

Ten volatile compounds derived from the cephalic glands of the fire beeTrigona (Oxytrigona)mellicolor were bioassayed for possible allomonal activities facilitating nest plundering. Two diketones, (E)-3-heptene-2,5-dione and (E)-3-nonene-2,5-dione, caused the honeybeeApis mellifera to display avoidance behavior and reduced defensive behavior. These diketones are produced in relatively large quantities in fire-bee cephalic glands.