Vespa velutina nest distribution at a local scale: An 8‐year survey of the invasive honeybee predator

Vespa velutina is an invasive species that was observed for the first time in France and Europe in 2004, which rapidly threatened domestic honeybees with active predation. For the first time in this study, we analyzed the distribution of V. velutina nests at a local scale to understand the pattern of nesting, and in 8 years of monitoring, a total of 528 nests were surveyed. With the exception of 2 years, the nests of V. velutina were randomly distributed within the monitored area, which suggested that intraspecific competition for nesting sites and/or food was unlikely. When the data for all years were combined, an aggregated distribution of nests at the seafront in the vicinity of the oyster farm and sportfishing activities was observed. This distribution suggested that seafood, attractive to vespids, might provide a valuable alternative food source that favored colony development. We also tested the effect of spring queen trapping of V. velutina on the distribution of nests in 2014, which was the year with the greatest number of colonies within the area; the position of the traps did not influence the distribution of the nests. For the first time, this study showed that (i) intraspecific competition was unlikely to be a mechanism for population regulation, (ii) some areas were more likely favored for hornet nests, and (iii) spring queen wasp trapping was inefficient as a method to limit the distribution of the V. velutina population.     

幼虫信息素中三种酯类对中华蜜蜂和意大利蜜蜂工蜂哺育和封盖行为以及蜂王发育影响

为研究蜜蜂幼虫信息素中3种酯类成分（甲基棕榈酸酯、乙基棕榈酸酯和乙基油酸酯）对中华蜜蜂Apis cerana cerana和意大利蜜蜂Apis mellifera ligustica工蜂哺育行为、封盖行为以及蜂王发育影响, 在人造蜂蜡王台中加入1%和0.1%（w/w）的3种酯类作为实验组, 以不添加酯类（0%）的为对照组, 移入1日龄工蜂幼虫, 测定王台接受率、单个王台中幼虫和王浆重量; 另将分别添加1%和0.1%（w/w）3种酯类的石蜡假幼虫放入工蜂巢房中, 同样设对照组, 测定假幼虫的封盖率; 在新鲜王浆中以1%和0.1%（w/w）分别加入3种酯类作为实验组, 以不添加酯类（0%）的作为对照组, 再分别在1日龄、2日龄和3日龄幼虫王台中加入0.01 mL含有酯类的蜂王浆, 并测定蜂王初生重和卵巢管数量。结果表明: 0.1%甲基棕榈酸酯可以显著提高中蜂和意蜂幼虫重量; 意蜂的甲基棕榈酸酯和乙基油酸酯两个实验组(1.0%, 0.1%)假幼虫封盖率都极显著高于对照组; 乙基油酸酯两个实验组(1.0%, 0.1%)都显著降低了中蜂和意蜂蜂王初生重和卵巢管数量。这说明不同蜜蜂幼虫信息素具有不同的生物学效应。     

A newly-discovered mode of colony founding among fire ants

Summary Queen ants start new colonies either unassisted by workers (independent founding), assisted by workers from their natal nest (dependent founding), or assisted by the workers of other species (dependent, socially parasitic). The monogyne form of the fire ant,Solenopsis invicta, founds independently in summer, but in the fall it also produces a few sexuals some of which overwinter, then fly and mate in early spring. These overwintered queens lack the nutritional reserves and behaviors for independent colony founding. Rather, they seek out unrelated, mature, orphaned colonies, enter them and exploit the worker force to found their own colony through intraspecific social parasitism. Success in entering orphaned colonies is higher when these lack overwintered female alates of their own. When such alates are present, orphaning causes some to dealate and become uninseminated replacement queens, usually preventing entry of unrelated, inseminated replacement queens. Such colonies produce large, all-male broods. Successful entry of a parasitic queen robs the host colony of this last chance at reproductive success. Only overwintered sexuals take part in this mode of founding.     

The role of queen mandibular pheromone and colony congestion in honey bee (Apis mellifera L.) reproductive swarming (Hymenoptera: Apidae)

The roles of honey bee queen mandibular pheromone and colony congestion in the inhibition of swarming were investigated. Two colony siz.es were used: small, congested colonies and large, uncongested colonies. Both groups of colonies were treated with various dosages of the five-component, synthetic queen mandibular pheromone in the spring, and the extent and timing of swarming were followed. Most treatment groups received pheromone or a solvent blank (control) on a stationary slide; one group of the congested colonies received a pheromone treatment via an aerosol spray. The pheromone was not effective at delaying swarming in the congested colonies at any dosage applied on slides, but the aerosol spray-treated colonies swarmed significantly later in the season than the control colonies. The uncongested, pheromone-treated colonies exhibited a dose-dependent delay in swarming, with the highest dosage colonies swarming almost four weeks later than the control colonies. These results indicate an interaction between congestion and pheromone in the control of honey bee reproduction. While congestion may in itself be a factor stimulating swarming, these results are consistent with the interpretation that colony congestion reduces the transmission of queen pheromone within the nest, thereby removing the queen 's pheromone-based inhibition of queen rearing and subsequent swarming by workers.     

Queen number in a supercolony of the invasive garden ant, <Emphasis Type="Italic">Lasius neglectus</Emphasis>

Summary We have analysed the distribution of queens under stones at the core and at the periphery of a supercolony of Lasius neglectus that occupies 14 ha at Seva (NE Spain). Queens were not found alone, but rather within worker groups. Density at the center (mean ± s.d.: 1.38 ± 2.87 queens/stone; n = 100 stones; range 0–14) was not different from density at the periphery (1.18 ± 2.38; range 0–12). The estimate of the number of queens found under stones for the whole colony is about 35500. Egg-laying rates for queens from these two zones were obtained in the laboratory, at three different temperatures, and there were no differences detected. The presence of brood stages, from eggs to cocoons, was also similar in both zones. The homogeneous distribution of colony components may indicate that the area occupied by L. neglectus has already reached saturation. With a different technique – soil core extraction – we could estimate the density of workers in the soil: 800 workers per m². Soil cores had 6.28 ± 20.0 workers/core (range: 0–173), giving a rough estimate of 1.12 × 10⁸ workers in the soil, for the entire colony. Though few, some queens were also recovered from soil cores. Queen numbers for the supercolony, based on queens found in the soil, reaches the astounding level of 360000. Numbers are consistent with previous predictions.Received 10 September 2003; revised 1 December 2003; accepted 9 December 2003.     

育王框位置对中华蜜蜂蜂王质量的影响

蜂王质量的好坏决定了蜂群的群势和生产性能。培育优质的蜂王有利于蜂群的饲养管理及提高经济效益。在育王过程中,育王框所处位置对王台接受率以及蜂王质量均有所影响。本研究基于免移虫育王技术,以中华蜜蜂为研究对象,探究育王框在不同类型子脾之间的位置(封盖子脾之间、幼虫脾之间以及混合脾之间)对王台接受率、蜂王个体形态指标及蜂王卵巢卵黄原蛋白基因表达的影响。研究结果表明,育王框置于幼虫脾之间蜂王幼虫接受率和蜂王卵黄原蛋白表达量显著高于封盖子脾,但对蜂王个体指标无影响。     

MICROSATELLITES REVEAL HIGH POPULATION VISCOSITY AND LIMITED DISPERSAL IN THE ANT FORMICA PARALUGUBRIS

We used microsatellites to study the fine-scale genetic structure of a highly polygynous and largely unicolonial population of the ant Formica paralugubris. Genetic data indicate that long-distance gene flow between established nests is limited and new queens are primarily recruited from within their natal nest. Most matings occur between nestmates and are random at this level. In the center of the study area, budding and permanent connections between nests result in strong population viscosity, with close nests being more similar genetically than distant nests. In contrast, nests located outside of this supercolony show no isolation by distance, suggesting that they have been initiated by queens that participated in mating flights rather than by budding from nearby nests in our sample population. Recruitment of nestmates as new reproductive individuals and population viscosity in the supercolony increase genetic differentiation between nests. This in turn inflates relatedness estimates among worker nestmates (r = 0.17) above what is due to close pedigree links. Local spatial genetic differentiation may favor the maintenance of altruism when workers raise queens that will disperse on foot and compete with less related queens from neighboring nests or disperse on the wing and compete with unrelated queens.     

Suppression of queen rearing in European and Africanized honey beesApis mellifera L. by synthetic queen mandibular gland pheromone

Summary Queen rearing is suppressed in honey bees (Apis mellifera L.) by pheromones, particularly the queen's mandibular gland pheromone. In this study we compared this pheromonally-based inhibition between temperate and tropically-evolved honey bees. Colonies of European and Africanized bees were exposed to synthetic queen mandibular gland pheromone (QMP) for ten days following removal of resident queens, and their queen rearing responses were examined. Queen rearing was suppressed similarly in both European and Africanized honey bees with the addition of synthetic QMP, indicating that QMP acts on workers of both races in a comparable fashion. QMP completely suppressed queen cell production for two days, but by day six, cells containing queen larvae were present in all treated colonies, indicating that other signals play a role in the suppression of queen rearing. In queenless control colonies not treated with QMP, Africanized bees reared 30% fewer queens than Europeans, possibly due to racial differences in response to feedback from developing queens and/or their cells. Queen development rate was faster in Africanized colonies, or they selected older larvae to initiate cells, as only 1 % of queen cells were unsealed after 10 days compared with 12% unsealed cells in European colonies.     

Variation in worker response to honey bee (Apis mellifera L.) queen mandibular pheromone (Hymenoptera: Apidae)

Genetic and environmental influences on the worker honey bee retinue response to queen mandibular gland pheromone (QMP) were investigated. Worker progeny were reared from queens originating from four sources: Australia, New Zealand, and two locations in British Columbia, Canada (Simon Fraser University and Vancouver Island). Progeny from New Zealand queens responded significantly higher (P < 0.05) than progeny from Australia in a QMP retinue bioassay. Retinue response was not related to queen production of pheromone or colony environment, and the strain-dependent differences in retinue bioassay responses were maintained over a wide range of dosages. Selected high- and low-responding colonies were bioassayed over the course of 1 year. High-responding colonies contacted QMP lures more frequently than low-responding colonies (P < 0.05) throughout the year except in late summer. We conclude that there is a strong genetic component to QMP response by worker honey bees, as well as a seasonal effect on response.     

Sperm viability and gene expression in honey bee queens (Apis mellifera) following exposure to the neonicotinoid insecticide imidacloprid and the organophosphate acaricide coumaphos

Honey bee population declines are of global concern. Numerous factors appear to cause these declines including parasites, pathogens, malnutrition and pesticides. Residues of the organophosphate acaricide coumaphos and the neonicotinoid insecticide imidacloprid, widely used to combat Varroa mites and for crop protection in agriculture, respectively, have been detected in wax, pollen and comb samples. Here, we assess the effects of these compounds at different doses on the viability of sperm stored in the honey bee queens’ spermatheca. Our results demonstrate that sub-lethal doses of imidacloprid (0.02 ppm) decreased sperm viability by 50%, 7 days after treatment. Sperm viability was a downward trend (about 33%) in queens treated with high doses of coumaphos (100 ppm), but there was not significant difference. The expression of genes that are involved in development, immune responses and detoxification in honey bee queens and workers exposed to chemicals was measured by qPCR analysis. The data showed that expression levels of specific genes were triggered 1 day after treatment. The expression levels of P450 subfamily genes, CYP306A1, CYP4G11 and CYP6AS14 were decreased in honey bee queens treated with low doses of coumaphos (5 ppm) and imidacloprid (0.02 ppm). Moreover, these two compounds suppressed the expression of genes related to antioxidation, immunity and development in queens at day 1. Up-regulation of antioxidants by these compounds in worker bees was observed at day 1. Coumaphos also caused a repression of CYP306A1 and CYP4G11 in workers. Antioxidants appear to prevent chemical damage to honey bees. We also found that DWV replication increased in workers treated with imidacloprid. This research clearly demonstrates that chemical exposure can affect sperm viability in queen honey bees.