Assessing the density of honey bee colonies at ecosystem scales

1. Information about the density of wild honey bee (Apis spp.) colonies in an ecosystem is central to understanding the functional role of honey bees in that ecosystem, necessary for effective biosecurity response planning, and useful for determining whether pollination services are adequate. However, direct visual surveys of colony locations are not practical at ecosystem scales. Thus, indirect methods based on population genetic analysis of trapped males have been proposed and implemented. 2. In this review, indirect methods of assessment of honey bee colony densities are described, which can be applied at ecosystem scales. The review also describes how to trap males in the field using the Williams drone trap (or virgin queens) the appropriate genetic markers and statistical analyses, and discusses issues surrounding sample size. 3. The review also discusses some outstanding issues concerning the methods and the conversion of estimated colony number to colony density per km². The appropriate conversion factor will require further research to determine the area over which a drone trap draws drones.     

Regional walrus abundance estimate in the United States Chukchi Sea in autumn

Human activities (e.g., shipping, tourism, oil, gas development) have increased in the Chukchi Sea because of declining sea ice. The declining sea ice itself and these activities may affect Pacific walrus (Odobenus rosmarus divergens) abundance; however, previous walrus abundance estimates have been notably imprecise. When sea ice is absent from the eastern Chukchi Sea, walruses in waters of the United States usually rest together onshore at a single Alaska coastal haulout, where they can be surveyed more easily than when they rest on dispersed offshore ice floes. We estimated the number of walruses on land (herd size) at this haulout from 13 unoccupied aircraft system (UAS) surveys flown within a 10-day period in each of 2018 and 2019. We estimated population size of walruses using the haulout over the course of the surveys by combining herd size data with data from satellite-linked transmitters that indicated whether tagged walruses were in or out of water during each survey. Our estimates of the population size of walruses using the haulout during each year's survey period were similar to each other and more precise than historical walrus abundance estimates: posterior means (95% credibility intervals) were 166,000 (133,000–201,000) for 2018 and 189,000 (135,000–251,000) for 2019. Auxiliary observations support using these estimates to represent the size of the population using the eastern Chukchi Sea in autumn during the surveyed years. Our study site was the only substantial Chukchi Sea coastal haulout in the United States during the survey periods and study-specific tracking data (consistent with known distribution and movement patterns) indicated tagged walruses remained in eastern Chukchi waters during the survey periods. In addition, the imagery, telemetry, and analytical methods developed for this study advance the prospect for precise range-wide walrus population size estimates.     

MtDNA COI‐COII marker and drone congregation area: An efficient method to establish and monitor honeybee (Apis mellifera L.) conservation centres

Honeybee subspecies have been affected by human activities in Europe over the past few decades. One such example is the importation of nonlocal subspecies of bees which has had an adverse impact on the geographical repartition and subsequently on the genetic diversity of the black honeybee Apis mellifera mellifera. To restore the original diversity of this local honeybee subspecies, different conservation centres were set up in Europe. In this study, we established a black honeybee conservation centre Conservatoire de l'Abeille Noire d'Ile de France (CANIF) in the region of Ile‐de‐France, France. CANIF's honeybee colonies were intensively studied over a 3‐year period. This study included a drone congregation area (DCA) located in the conservation centre. MtDNA COI‐COII marker was used to evaluate the genetic diversity of CANIF's honeybee populations and the drones found and collected from the DCA. The same marker (mtDNA) was used to estimate the interactions and the haplotype frequency between CANIF's honeybee populations and 10 surrounding honeybee apiaries located outside of the CANIF. Our results indicate that the colonies of the conservation centre and the drones of the DCA show similar stable profiles compared to the surrounding populations with lower level of introgression. The mtDNA marker used on both DCA and colonies of the conservation centre seems to be an efficient approach to monitor and maintain the genetic diversity of the protected honeybee populations.     

意大利蜜蜂刚出房与性成熟雄蜂的蛋白质组差异分析

【目的】对意大利蜜蜂Apis mellifera ligustica刚出房雄蜂与性成熟雄蜂的蛋白质组进行比较,探讨雄蜂在性成熟过程中蛋白质表达变化,为进一步研究雄蜂发育生物学获得差异表达蛋白质方面的依据。【方法】采用双向电泳法建立意大利蜜蜂雄蜂发育过程中刚出房时与性成熟期的蛋白质表达谱,通过质谱分析与数据库检索,鉴定部分差异蛋白。【结果】在意大利蜜蜂刚出房雄蜂和性成熟雄蜂中分别检测到2 490和2 317个蛋白点,其中差异表达蛋白点有157个。在刚出房雄蜂中高度表达的蛋白点有102个;在性成熟雄蜂中高度表达的蛋白点有55个。对部分差异蛋白进行质谱分析,共鉴定了18个蛋白点,其中在刚出房雄蜂中上调表达的蛋白有肌钙蛋白、SEC13蛋白、DJ蛋白等,在性成熟雄蜂中上调表达的蛋白有副肌球蛋白、精氨酸激酶、肌动蛋白解聚因子等。【结论】意大利蜜蜂雄蜂在性成熟发育过程中,其体内大量蛋白表达发生了变化,其差异表达的蛋白质可能与骨骼、飞行肌以及精子发育等机能有关。     

Temporal variation in the genetic structure of a drone congregation area: an insight into the population dynamics of wild African honeybees (Apis mellifera scutellata)

The mating system of the honeybee ( Apis mellifera ) has been regarded as one of the most panmictic in the animal kingdom, with thousands of males aggregating in drone congregation areas (DCAs) that virgin queens visit to mate with tens of partners. Although males from many colonies gather at such congregations, the temporal changes in the colonies contributing drones remain unknown. Yet, changes in the DCAs' genetic structure will ultimately determine population gene flow and effective population size. By repeatedly sampling drones from an African DCA over a period of 3 years, we studied the temporal changes in the genetic structure of a wild honeybee population. Using three sets of tightly linked microsatellite markers, we were able to reconstruct individual queen genotypes with a high accuracy, follow them through time and estimate their rate of replacement. The number of queens contributing drones to the DCA varied from 12 to 72 and was correlated with temperature and rainfall. We found that more than 80% of these queens were replaced by mostly unrelated ones in successive eight months sampling intervals, which resulted in a clear temporal genetic differentiation of the DCA. Our results suggest that the frequent long-range migration of colonies without nest-site fidelity is the main driver of this high queen turnover. DCAs of African honeybees should thus be regarded as extremely dynamic systems which together with migration boost the effective population size and maintain a high genetic diversity in the population.     

中华蜜蜂雄蜂脑部组织结构观察

通过组织化学方法,对中华蜜蜂Apis cerana cerana Fabricius雄蜂的脑部的形态结构进行观察。结果表明,雄蜂的脑由前脑、中脑和后脑三部分构成,前脑视叶两侧具有大而显著的复眼,而其他结构相对较小。蕈形体在脑中所占的比例小于工蜂和蜂王;中心体的比例小于工蜂,与蜂王接近;中脑的嗅叶相对较为发达,这使它们在同蜂王的交配过程中,能够更灵敏地接收来自于蜂王性外激素的刺激。中华蜜蜂雄蜂的嗅叶具有性二态现象,但是与意大利蜜蜂Apis mellifera L.雄蜂发达的巨大纤维球复合体相比,中华蜜蜂并不明显;除此之外,它们在脑部结构上没有显著差异。     

Difficulties of assessing the impacts of the 2019–2020 bushfires on koalas

The 2019–2020 Australian bushfires were unprecedented both in extent and severity, impacting wildlife through direct mortality as well as habitat damage. More than 10% of koala habitat is estimated to have been affected by fires. Estimating the number of koalas lost is crucial to assess koala conservation status and to determine the appropriate management actions required. However, this is not a trivial task, as accurate data on koala distribution and population density before the fires is patchy. Acknowledging this weakness, we sought to estimate fire impact on koalas at specific sites, by comparing habitat areas affected by the fire with habitat areas that were unaffected by the fire, pairing closely related study sites (based on geography and vegetation). To compare koala density, we deployed two koala detection methods; drone-acquired thermal imagery and detection dogs coupled with genetic fingerprinting, in four fire-affected sites paired with four control sites in New South Wales and Queensland. Through drone surveys, we detected 140 koalas in 5,240 ha in New South Wales. The detection dogs found 144 scat samples corresponding to 79 unique koalas in 77 ha of transects in Queensland. Our preliminary results show many koalas were still present in fire-affected areas after the 2019–2020 bushfire season. Koala density was 24 to 71% lower in fire-affected sites compared with control sites in three of the habitat pairs, whereas unexpectedly, in the fourth pair, we observed a 317% higher koala density in the fire-affected site. This underlined that koalas can be present in fire-affected areas and that monitoring their health could be critical for months after the fires.     

The honeybee queen influences the regulation of colony drone production

Social insect colonies invest in reproduction and growth, buthow colonies achieve an adaptive allocation to these life-historycharacters remains an open question in social insect biology.Attempts to understand how a colony's investment in reproductionis shaped by the queen and the workers have proved complicatedbecause of the potential for queen–worker conflict overthe colony's investment in males versus females. Honeybees,in which this conflict is expected to be minimal or absent,provide an opportunity to more clearly study how the actionsand interactions of individuals influence the colony's productionand regulation of males (drones). We examined whether honeybeequeens can influence drone regulation by either allowing orpreventing them from laying drone eggs for a period of timeand then examining their subsequent tendency to lay drone andworker eggs. Queens who initially laid drone eggs subsequentlylaid fewer drone eggs than the queens who were initially preventedfrom producing drone eggs. This indicates that a colony's regulationof drones may be achieved not only by the workers, who buildwax cells for drones and feed the larvae, but also by the queen,who can modify her production of drone eggs. In order to betterunderstand how the queen and workers contribute to social insectcolony decisions, future work should attempt to distinguishbetween actions that reflect conflict over sex allocation andthose that reflect cooperation and shared control over the colony'sinvestment in reproduction.     

Pheromonal activity and fine structure of the mandibular glands of honeybee drones (Apis mellifera L.) (Insecta,Hymenoptera, Apidae)

Experiments were conducted to determine the role of drone mandibular gland secretions in attracting flying drones and the effect of age on the secretory activity. Extracts of mandibular glands and of cephalic tissues were applied to cotton lures which were attached below balloons tethered at 8–12 m above the ground. Most flying drones were attracted to extracts of mandibular glands but a few were drawn to other cephalic tissues or to solvent controls. Histological and electron microscope studies showed that the structure of the tiny (0.12 mm long) mandibular gland varied according to age. Its secretory activity in 0–3-day old drones was evident from the abundant rough endoplasmic reticulum. At 7-days the glands were fully developed. After 9 days the glands were no longer active and showed an autolytic process; the product was stored in the gland lumen for further emission during drone mating flights.     

Evaluating behavioral responses of nesting lesser snow geese to unmanned aircraft surveys

Unmanned aircraft systems (UAS) are relatively new technologies gaining popularity among wildlife biologists. As with any new tool in wildlife science, operating protocols must be developed through rigorous protocol testing. Few studies have been conducted that quantify the impacts UAS may have on unhabituated individuals in the wild using standard aerial survey protocols. We evaluated impacts of unmanned surveys by measuring UAS‐induced behavioral responses during the nesting phase of lesser snow geese (Anser caerulescens caerulescens) in Wapusk National Park, Manitoba, Canada. We conducted surveys with a fixed‐wing Trimble UX5 and monitored behavioral changes via discreet surveillance cameras at 25 nests. Days with UAS surveys resulted in decreased resting and increased nest maintenance, low scanning, high scanning, head‐cocking and off‐nest behaviors when compared to days without UAS surveys. In the group of birds flown over, head‐cocking for overhead vigilance was rarely seen prior to launch or after landing (mean estimates 0.03% and 0.02%, respectively) but increased to 0.56% of the time when the aircraft was flying overhead suggesting that birds were able to detect the aircraft during flight. Neither UAS survey altitude nor launch distance alone in this study was strong predictors of nesting behaviors, although our flight altitudes (≥75 m above ground level) were much higher than previously published behavioral studies. Synthesis and applications: The diversity of UAS models makes generalizations on behavioral impacts difficult, and we caution that researchers should design UAS studies with knowledge that some minimal disturbance is likely to occur. We recommend flight designs take potential behavioral impacts into account by increasing survey altitude where data quality requirements permit. Such flight designs should consider a priori knowledge of focal species’ behavioral characteristics. Research is needed to determine whether any such disturbance is a result of visual or auditory stimuli.