Apidologie最新文献

Stingless bees are increasingly in demand as pollinators in agricultural crops within the tropics and subtropics. Hive splitting, where one strong managed hive is “split” into two independent daughter colonies, is commonly used to increase hive numbers. However, how splitting impacts foraging behaviour or the time taken for the colony to recover from splitting has not previously been studied. We assessed the impact of splitting on the foraging behaviour of Tetragonula carbonaria colonies. The number of returning forager trips and foraged proportions of pollen, nectar and resin was observed after splitting and compared with unsplit control hives over a 31-day period. We found the total amount of returning foragers in split hives reduced to less than a third of unsplit hives (unsplit median, 184–288; split median, 19–61) for 16 days, while returning nectar (unsplit median, 89–147; split median, 16–28) and pollen (unsplit median, 55–155; split median, 1–7) foragers reduced to less than a quarter of unsplit hives for 9 days following splitting. After 31 days, the number of total, nectar and pollen foraging trips had still not recovered to levels observed in unsplit hives. Resin foraging trips however were not significantly different to unsplit hives after only 10 days. The colony foraging allocation to resin (proportion) increased after splitting and was significantly higher in split hives until day 16 of the experiment (unsplit median, 0.03–0.05; split median, 0.10–0.16). Our results demonstrate that split colonies prioritise resin collection and foraging on floral resources is reduced. We recommend that hives should not be split within 31 days of being used for pollination, and resin sources should be conserved where possible and supplemented where necessary due the vital roles of the resource.

Nectar is the resource that sustains honey bee colonies through periods of dearth and provides the surplus honey beekeepers harvest for human consumption. While extensive information is available for plants that honey bees visit for pollen and nectar, we lack knowledge on which nectars are stored long-term as honey for harvest and support of colonies through winter. Here, we used citizen science methods and pollen metabarcoding analysis to identify the plants contributing most to honey samples harvested by beekeepers from apiaries with variable intensities of surrounding agriculture. A total of 36 samples were collected from 36 apiaries in Ohio in 2019, with an average of 3 plant genera detected per sample. We found similarity in honey samples collected from all apiaries, regardless of the proportion of agricultural land within a 2-km foraging range, with substantial amounts of honey stored from spring trees, including Salix (willow) and Prunus (cherry). This result suggests the importance of early-season resources regardless of agricultural intensity in the surrounding landscape. This study contributes to a body of work aiming to identify the nectars making it to long-term honey storage and those that are being consumed within the hive shortly after collection.

Arylalkylamine N-acetyltransferase (AANAT) is a large family of enzymes that catalyze the acetyl-CoA-dependent acetylation of an amine or arylalkylamine. Some AANATs, such as serotonin N-acetyltransferase, in vertebrates are photosensitive and mediate circadian regulation of melatonin and are involved in important biological processes. We analyzed AANAT activity of the honey bee, Apis mellifera, and found a relationship to the polyethism of workers. Crude AANAT solutions from isolated heads had optimum pHs at 8.0 (a minor peak) and 10.0 (a major peak). The Lineweaver–Burk (or double reciprocal plot) and the secondary plot (derived from the Lineweaver–Burk), gave the K_m for tryptamine (substrate) as 2.65 µM, and the V_max of 53.2 nmol/mg protein/min. The apparent K_m and V_max for acetyl-CoA was 20.5 µM and 6.98 nmol/mg protein/min, respectively. AANAT activity showed a correlation with the age of workers. The highest AANAT activity was found in 42-day old workers and the lowest in 3-day old workers. The highest AANAT activity was found in foragers and the lowest in hive-making workers. Two AANAT genes were retrieved from the A. mellifera genome. Putative cis-acting elements involved in circadian regulation, metamorphic and caste related expression were explored within both genes to discuss potential implication of the circadian clock in regulation of polyethism. The results suggest that AANATs are associated with regulation of social behavior in honey bees in circadian manners, in both foraging rhythms and polyethism.

We studied an aggregation of Apis laboriosa colonies in northern Vietnam where the species is sympatric with Apis dorsata. We video-recorded four colonies on 2 days to quantify drone flights and other colony behaviors. We observed > 90% of drones between 16:10 and 18:10 h ICT, with the maximum numbers between ~ 17:10 and 18:00 h. Drone flight timing did not differ between days or between colonies. Aggressive worker behavior toward some arriving drones suggests considerable drifting of drones between nests. Massed flight activity, a colony behavior in which a high proportion of bees temporarily leaves the comb, occurred in several colonies between 14:00 and 16:40 h. We also documented absconding by one colony. A. laboriosa drones ended their mating flights before the typical mating flight time of Apis dorsata at evening twilight. We conclude that allochrony of mating is a likely reproductive isolating mechanism between these two species of giant honey bees.

The tiny population of the endemic Maltese honey bee (A. m. ruttneri) is threatened by anthropogenic influences, such as urbanisation, habitat loss, and unsustainable agricultural practices, but most prominently by the importation of commercially important non-native stock. To obtain data on the colony life cycle parameters of A. m. ruttneri and to measure its apicultural performance in relation to imported A. m. ligustica under Maltese conditions, we conducted a comparative study between mid-2017 and early 2020. Over one full season, colonies of both subspecies (A. m. ruttneri (n = 15) vs. A. m. ligustica (n = 18)) were regularly assessed for survival, colony size, behaviour, and presence of diseases. The comparative assessments were completed in September 2018, but monitoring and sampling of the surviving colonies of A. m. ruttneri continued until March 2020. Our results clearly indicate that the tested group of sister queens of A. m. ruttneri is well adapted to the prevailing environmental conditions in Malta. The colonies survived significantly longer compared to the tested group of sister queens of A. m. ligustica and performed better in several parameters measured, their colony development, and health being well in tune with the environment. A. m. ruttneri received acceptable scores for behavioural traits (gentleness and calmness on the comb), showing potential for improvement by breeding. The results from this pioneering study clearly indicate that A. m. ruttneri, with its superior adaptation to Maltese conditions and the potential to improve by breeding, represents a prime option towards economically sound beekeeping on the Maltese archipelago.

This study assessed the conservation status of the Saharan honey bee (Apis mellifera sahariensis) from southeastern Morocco using 12 microsatellite loci to examine genetic diversity and hybridization with other subspecies. Samples from 148 colonies were clustered into seven populations representing the expected distribution of A. m. intermissa and A. m. sahariensis, and reference samples from two European subspecies, A. m. carnica and A. m. mellifera, were included. Moroccan honey bees showed higher genetic diversity than European reference samples, and genetic structure analysis revealed two distinct clusters in Morocco separated by the High Atlas Mountains (F_ST = 0.05). Although high rates of hybridization with A. m. intermissa jeopardize the genetic integrity of the Saharan honey bee, no evidence of introgression was detected from the European reference subspecies. Additionally, we found that the probability of assignment to Saharan subspecies decreased with increasing human management intensity and precipitation. These findings are important for developing a conservation strategy for the Saharan honey bee in Morocco.

Our study investigated the possibility of using the red mason bee Osmia bicornis as a pollinator of forest seed orchards of frequently grown European trees: insect - pollinated Tilia cordata and Prunus avium. Moreover, we checked whether the presence of O. bicornis has an impact on the pollination results of Quercus petraea, which is wind - pollinated. Data were collected from 8 forest seed orchards in western Poland between 2018 and 2020. We assessed whether the presence of O. bicornis populations affects the number and mass of seeds and seed quality. Supplementing forest orchards with O. bicornis affected seed yield. The generalized linear mixed models indicated that the number of seeds and the proportion of viable seeds, but not seed mass, were higher in the Tilia cordata trees, when additionally pollinated with O. bicornis added as a pollinator.

Bee development is determined by the quantity and quality of food resources available in the environment that can be used by bees only to a certain extent. Therefore, this study aimed to evaluate, by means of changes in hive weight, the amount of food collected by honey bees in various landscapes, in relation to meteorological conditions, landscape, and forest structure. The monitored colonies (n = 104) were placed on electronic beehive scales, which provided data about hive weight, temperature, and humidity over two beekeeping seasons. The landscape valuation within a 2 km radius from each beehive was prepared based on digital maps. The seasonal distribution of food resources collected by honey bees was determined based on hive weight changes analysed in 5-day-periods (i.e. pentads). The hive weight changes mainly depended on the observation period and the air temperature. The hive weight increased from April to the last 10 days of June and when the air temperature was over 24 °C. The proportions of agricultural lands and forests, as well as the air humidity, had a small effect on hive weight changes. Continuous monitoring of the weight of honey bee colonies on a large scale showed that honey bees collected food stores in their nests mainly in the spring. Then, they collected a small amount of food, probably due to limited access to food resources from the last 10 days of June until the end of the growing season.

The widespread use of neonicotinoid insecticides in the agricultural ecosystems is said to be one of the causes for the alarming bee decline observed around the world. However, the evidences against neonicotinoids are inconclusive. In this study, we assessed the impact of neonicotinoids (imidacloprid, and thiamethoxam), when applied as seed treatment and foliar sprays, on the foraging activity of honey bees. When applied as seed treatment, residues of the tested molecules in the pollen and nectar samples were present below quantifiable levels (< LOQ). At 3 days after spraying, residues of imidacloprid and thiamethoxam were 0.86 and 0.96 mg/kg in the leaf samples, 0.15 and 0.23 mg/kg in the pollen samples, and 0.07 and 0.07 mg/kg in the nectar samples, respectively. Further, the foraging activity of the bees did not appear to be impacted when neonicotinoids were applied as seed treatment. Contrarily, foliar application of the neonicotinoides significantly reduced the foraging activity between 1 and 3 days after application. Nonetheless, the foraging activity was comparable to the control levels 7 days after spraying. It appears that there is little short-term impact of neonicotinoids on the foraging activity of bees, especially when applied as seed treatment.