Search

Advancements in agricultural production have seen the rapid adoption of protected cropping systems globally. Such systems have been optimized for plant growth and efficiency, with little understanding of the potential impacts to key insect pollinators. Here, we investigate the effect of bird netting and polythene rain covers on the health and performance of honey bees (Apis mellifera L.) during the pollination of sweet cherry crops. Over two consecutive seasons, 12 full‐strength colonies were equipped with tagged bees and radio frequency identification (RFID) systems. The colonies were equally divided between open control, bird netted and polythene (semi‐permanent VOEN in 2019 and retractable Cravo in 2020) groups. Over 1300 individual bees were monitored for the duration of the commercial pollination period to determine behavioural parameters such as foraging commencement age, number and duration of trips and overall survival. Bees began foraging within the optimum age range (mean 15.7–24.1 days) under all covering types, with little indication of prolonged stress or increased mortality during the short season. Polythene covers (VOEN & Cravo) were found to significantly increase the total time needed for bees to orientate successfully. Once orientated, bees placed under covers conducted up to 155% more foraging trips, with a longer cumulative duration. Covering type was found to significantly impact the amount and type of pollen collected, with the most restrictive system (VOEN) yielding the highest proportion of cherry pollen. Overall, we found little evidence to suggest that the tested protective covers have a detrimental impact to honey bee foraging in cherry crops. [ABSTRACT FROM AUTHOR]

Hybrid vegetable varieties have become essential for global agricultural production, offering key advantages for yield, quality and disease resistance. The production of hybrid seeds is however limited by pollination challenges, with these systems commonly associated with unattractive and low‐quality floral resources, isolated growing environments and frequent insecticide applications.Here, we utilise commercial carrot seed crops to investigate the impact of hybrid pollination on the behaviour of the honey bee (Apis mellifera).Six full‐strength bee colonies were equipped with solar powered radio frequency identification systems and over 900 tagged bees per season. These colonies were deployed to commercial hybrid seed crops over two consecutive seasons. The colonies were allocated to either an on‐crop or off‐crop group. Individual bees were autonomously monitored for the pollination period to assess key parameters such as survival, age at foraging and the number and duration of orientation and foraging trips.Hybrid carrots were found to have a significant impact on bee foraging behaviour. Bees situated on the carrot crop undertook less frequent yet longer foraging trips, resulting in less total time outside of the colony compared to off‐crop bees. However, bees placed in carrot fields survived to an older age, orientated successfully, became foragers later and collected more pollen by weight, despite only 2% originating from carrot. We hope that the improved behavioural understanding can be utilised to enhance both pollinator health and hybrid seed production globally. [ABSTRACT FROM AUTHOR]

Chemical miticides are used routinely in honey bee colonies worldwide as treatment for the parasitic mite Varroa destructor, but there have been very few long-term colony-level field studies of the impacts of miticides on the bees themselves. Lab-based studies with individual bees or bees in small groups have highlighted many negative effects of miticides on bee behaviour and physiology; hence, there is an urgent need to better understand the consequences of miticides on honey bee colonies in an apicultural setting. Here we compared effects of commercial treatments of the miticides tau-fluvalinate and thymol, and controls, on honey bee colonies and bee foraging behaviour over five months, from autumn through winter in Sydney, Australia. Since V. destructor does not occur in Sydney, in this study, we could isolate the direct effects of the miticides from indirect effects resulting from reduced mite load. We found the autumn treatment of either miticide caused no significant change in bee adult or brood population or size of food stores. The average temperature in the thymol group differed from the temperature in the control group and was lower during winter. Neither miticide reduced bee longevity. Tau-fluvalinate caused bees to start foraging earlier in life and perform shorter trips, but no other effects on foraging behaviour were documented. To conclude, in Sydney, Australia, limited negative effects of autumn thymol or tau-fluvalinate treatments were observed on bees or bee colony performance. [ABSTRACT FROM AUTHOR]

Despite growing concerns over the impacts of agricultural pesticides on honey bee health, miticides (a group of pesticides used within hives to kill bee parasites) have received little attention. We know very little about how miticides might affect bee cognition, particularly in interaction with other known stressors, such as crop insecticides. Visual learning is essential for foraging bees to find their way to flowers, recognize them, and fly back to the nest. Using a standardized aversive visual conditioning assay, we tested how field exposure to three pesticides affects visual learning in European honey bees (Apis mellifera). Our pesticides were two common miticides, thymol in the commercial formulation Apiguard® and tau-fluvalinate in the formulation Apistan® and one neonicotinoid, imidacloprid. We found no effect of miticides alone, nor of field-relevant doses of imidacloprid alone, but bees exposed to both thymol and imidacloprid showed reduced performance in the visual learning assay. [ABSTRACT FROM AUTHOR]

Pesticide residues have been linked to reduced bee health and increased honey bee colony failure. Most research to date has investigated the role of pesticides on individual honey bees, and it is still unclear how trace levels of pesticides change colony viability and productivity over seasonal time scales. To address this question we exposed standard bee colonies to chemical stressors known to have negative effects on individual bees, and measured the productivity of bee colonies across a whole year in two environments: near Tucson Arizona and Sydney Australia. We exposed hives to a trace amount of the neonicotinoid imidacloprid and to the acaricide thymol, and measured capped brood, bee and honey production, as well as the temperature and foraging force of the colonies. The effect of imidacloprid on colony dynamics differed between the two environments. In Tucson we recorded a positive effect of imidacloprid treatment on bee and brood numbers. Thymol was associated with short-term negative effects on bee numbers at both locations, and may have affected colony survival at one location. The overall benefits of thymol for the colonies were unclear. We conclude that long-term and colony-level measures of the effects of agrochemicals are needed to properly understand risks to bees. Unlabelled Image • It is still unclear how most agrochemicals affect colonies of European honey bees. • We treated hives with different pesticides and measured their condition for a year. • We measured bees, brood, honey, temperature and mass change at two locations. • Effects of chemical stressors varied strongly across environments. • Pesticides impacts on colonies must be studied over the long term to evaluate impact. [ABSTRACT FROM AUTHOR]

The parasitic mite Varroa destructor is a major threat to the European honey bee Apis mellifera. Beekeepers apply the miticide thymol directly within the hives to kill this parasitic mite. Thymol is repellent to bees and causes them to ventilate the hive, yet its impact on bee hygienic behaviours that prevent the spread of diseases has never been studied. We measured the efficiency of colonies at removing dead adult bees, uncapping dead pupal cells and removing dead brood in two miticide-free Australian environments where the mite is absent. Thymol increased the uncapping and removal of dead brood by 24 to 36% after 48 h at both locations but had no effect on the removal of dead adult bees. The increased removal of brood could enhance the effect of thymol on V. destructor, especially if bees preferentially remove cells infected with the mite. [ABSTRACT FROM AUTHOR]

Precise, objective data on brood and honey levels in honey bee colonies can be obtained through the analysis of hive frame photographs. However, accurate analysis of all the frame photographs from medium- to large-scale experiments is time-consuming. This limits the number of hives than can be practically included in honeybee studies. Faster estimation methods exist but they significantly decrease precision and their use requires a larger sample size to maintain statistical power. To resolve this issue, we created ‘CombCount’ a python program that automatically detects uncapped cells to speed up measurements of capped brood and capped honey on photos of frames. CombCount does not require programming skills, it was designed to facilitate colony-level research in honeybees and to provide a fast, free, and accurate alternative to older methods based on visual estimations. Six observers measured the same photos of thirty different frames both with CombCount and by manually outlining the entire capped areas with ImageJ. The results obtained were highly similar between both the observers and the two methods, but measurements with CombCount were 3.2 times faster than with ImageJ (4 and 13 min per side of the frame, respectively) and all observers were faster when using CombCount rather than ImageJ. CombCount was used to measure the proportions of capped brood and capped honey on each frame of 16 hives over a year as they developed from packages to full-size colonies over about 60 days. Our data describe the formation of brood and honey stores during the establishment of a new colony. [ABSTRACT FROM AUTHOR]

Aim: Cities are thought to promote biological invasions because invasive species are more often introduced in urban areas and because they are more successful in disturbed environments. However, the association is not as strongly supported by the literature as is generally assumed and might depend on how urbanization and invasion are measured. In this study, we test if the type of data used to assess the link between urbanization and invasion can affect a study's conclusions. Location: Europe and middle Rhône valley (~5000 km2 in south‐eastern France). Method: We studied the spatial distribution of the invasive garden ant Lasius neglectus in its current introduced range in Europe and tested its association with urbanization using three measures of invasion (presence‐only, presence–absence and population area) and two measures of urbanization (urban/nonurban land cover classification and proportion of impervious surfaces (buildings, road) per spatial unit). Results: Based on presence‐only data across Europe, L. neglectus occurred in urban areas 10 times more often than expected from a random geographical distribution. However, when controlling for spatial bias in sampling effort with presence–absence data (1870 sampling locations in the middle Rhône valley, France), the occurrence of the species was independent of urbanization. Moreover, the surface occupied by L. neglectus populations was negatively correlated with urbanization. Main conclusions: These findings show that the type of occurrence data used to test the link between urbanization and invasion can strongly affect the conclusion of a study. This is particularly concerning because invasion studies often use presence‐only data that are likely biased towards cities. Future urban invasions studies must be carefully designed to avoid this pitfall. [ABSTRACT FROM AUTHOR]

Patterns in within-day hive weight data from two independent datasets in Arizona and California were modeled using piecewise regression, and analyzed with respect to honey bee colony behavior and landscape effects. The regression analysis yielded information on the start and finish of a colony’s daily activity cycle, hive weight change at night, hive weight loss due to departing foragers and weight gain due to returning foragers. Assumptions about the meaning of the timing and size of the morning weight changes were tested in a third study by delaying the forager departure times from one to three hours using screen entrance gates. A regression of planned vs. observed departure delays showed that the initial hive weight loss around dawn was largely due to foragers. In a similar experiment in Australia, hive weight loss due to departing foragers in the morning was correlated with net bee traffic (difference between the number of departing bees and the number of arriving bees) and from those data the payload of the arriving bees was estimated to be 0.02 g. The piecewise regression approach was then used to analyze a fifth study involving hives with and without access to natural forage. The analysis showed that, during a commercial pollination event, hives with previous access to forage had a significantly higher rate of weight gain as the foragers returned in the afternoon, and, in the weeks after the pollination event, a significantly higher rate of weight loss in the morning, as foragers departed. This combination of continuous weight data and piecewise regression proved effective in detecting treatment differences in foraging activity that other methods failed to detect. [ABSTRACT FROM AUTHOR]