Global warming could be beneficial to temperate crops owing to more suitable temperatures for photosynthesis, and traditionally managed crops with high field genetic diversity, such as wild blueberry, could show resilience under warming. However, warming can exacerbate water deficits, with its overall impacts on crops not fully understood. Here, we used a native North American fruit crop (wild blueberry) managed traditionally with naturally-growing plants and high diversity, as the model system to study warming impacts on its plant structure, physiology, and productivity (vegetative growth and berry yield). We implemented a warming simulation study in the field using active heating (AH; 3 to 4 degrees C; 3.5 degrees C average) and passive heating (PH; 1 to 2 degrees C; 1.5 degrees C) open-top chambers to compare with an ambient control in six genotypes over two years (2019 and 2020) in Maine, USA. Warming, especially active heating, resulted in lower soil volumetric water content (7.55 % decrease) and leaf water potentials (-0.49 MPa decrease) along with lower leaf chlorophyll, N, and K concentrations. However, we found no change in photosynthetic rate, while the photosynthetic rate per stem increased significantly due to increased leaf area. We also found that plants under warming were taller and had larger-in-diameter stems, as well as more and larger berries. The PH and AH increased yields by 1.9 and 5.5-fold, respectively. Yield correlated positively with higher photosynthesis under AH, and with boron concentration, flowers per stem, and negatively with chlorophyll concentrations across treatments. In summary, we were able to find both positive and negative effects of warming, but enhanced productivity in this temperate crop, highlighting that rising temperatures may be a boon to wild blueberry production when sufficient water and nutrients are present. The resilience of this traditionally managed crop with high genetic diversity provides insight into how we can sustain agricultural systems under global change.

Spotted-wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), is an invasive pest of thin-skinned fruits in the United States. Monitoring traps are an integral part of SWD integrated pest management, allowing early detection and timely management of this pest. An ideal monitoring trap should be easy to use, effective in capturing SWD, sensitive and selective to male SWD which are easy to identify due to their spotted wings, and able to predict fruit infestation from trap captures. Deli-cup-based liquid traps (grower standard), which make in-situ observations difficult, were compared with red-panel sticky traps, both baited with commercial lures (Scentry, Trécé Broad-Spectrum (BS), and Trécé High-Specificity (HS)), across several US states in blueberries (lowbush and highbush), blackberry, raspberry, and cherry crops during 2018 and 2021. Results showed that red-panel traps effectively captured SWD, were able to detect male SWD early in the season while also being selective to male SWD all season-long, and in some cases linearly related male SWD trap captures with fruit infestation. Scentry and Trécé BS lures captured similar numbers of SWD, though Trécé BS and Trécé HS were more selective for male SWD in red panel traps than liquid traps in some cases. In conclusion, due to its ease of use with less processing time, red-panel traps are promising tools for detecting and identifying male SWD in-situ and for predicting fruit infestation. However, further research is needed to refine the trap captures and fruit infestation relationship and elucidate the trap-lure interactions in berry and cherry crops.

The first major cleansing flight during the winter in a honey bee apiary was witnessed on February 6, 2021. A light snowfall and freezing rain prior to the flight allowed delineation of the distribution of distances from the aggregation of hives of fecal depositions and immobilized honey bees fallen to the ground. Five transects were surveyed radiating from the aggregation of four overwintered hives to collect the data. 'I he frequency distributions of these events were fit to Gamma probability density functions and then a test of the following hypothesis was constructed. Are cleansing flights solely comprised of local defecation by workers and then return to the hive? Or do workers also commence foraging in suboptimal air temperatures for flight? We found evidence that cleansing flights are comprised of two behaviors, local deposition of feces and long-distance foraging. This is based upon a significant difference (P < 0.001) between the mean distance from the hives of fecal deposition (3.01 +/- 0.36(se)) and immobilized bees on the ground (9.49 +/- 1.21(se)).

Pollinators, including honey bees, are responsible for the successful reproduction of more than 87% of flowering plant species: they are thus vital to ecosystem health and agricultural services world-wide. To investigate honey bee exposure to pesticides, 168 pollen samples and 142 wax comb samples were collected from colonies within six stationary apiaries in six U.S. states. These samples were analyzed for evidence of pesticides. Samples were taken bi-weekly when each colony was active. Each apiary included thirty colonies, of which five randomly chosen colonies in each apiary were sampled for pollen. The pollen samples were separately pooled by apiary. There were a total of 714 detections in the collected pollen and 1008 detections in collected wax. A total of 91 different compounds were detected: of these, 79 different pesticides and metabolites were observed in the pollen and 56 were observed in the wax. In all years, insecticides were detected more frequently than were fungicides or herbicides: one third of the detected pesticides were found only in pollen. The mean (standard deviation (SD)) number of detections per pooled pollen sample varied by location from 1.1 (1.1) to 8.7 (2.1). Ten different modes of action were found across all four years and nine additional modes of action occurred in only one year. If synergy in toxicological response is a function of simultaneous occurrence of multiple distinct modes of action, then a high frequency of potential synergies was found in pollen and wax-comb samples. Because only pooled pollen samples were obtained from each apiary, and these from only five colonies per apiary per year, more data are needed to adequately evaluate the differences in pesticide exposure risk to honey bees among colonies in the same apiary and by year and location.

Pollen-mediated gene flow was analyzed in two managed fields of lowbush blueberry (Vaccinium angustifolium Ait.) in Maine. Seedlings derived from open-pollinated crosses of two mother plants, one from each of the two fields, were genotyped using simple sequence repeat markers. The mother plants, the four to five nearest neighbour plants, and a group of 22–23 plants further away from the site of fruit collection were genotyped as well. The paternity of 70 seedlings produced by the mother plants, 35 from each field, was analyzed using FAMOZ to determine if each seedling was most likely a result of a self-cross, a cross with one of the nearest neighbours, or a cross from outside the nearest neighbourhood. Approximately 91%–97% of the seedlings appeared to result from crosses with plants outside the nearest neighbourhood, whereas 0% appeared to have resulted from self-crosses. This suggests that the primary pollinators of lowbush blueberry, native bees and honey bees, routinely collect and move pollen from distances greater than the adjacent neighbours of the plants receiving the pollen.

Wild blueberry, Vaccinium angustifolium Aiton, is a native forest understory plant that is managed as a fruit crop. Over the past 51 years, experiments have been conducted to investigate its reproduction. A model was developed that predicts bloom to begin at 100° days (base 4.4 °C) after 1 April and to end at 500° days for a period of three to four weeks. Flower stigmas are only receptive to pollen deposition for eight to 10 days, and the rate of fruit set declines rapidly after four days. Placement of pollen upon receptive stigmas suggests that fruit set occurs with as little as a single pollen tetrad. Twelve tetrads result in 50% fruit set. Several years of exploratory fruit set field experiments show viable seeds per berry, which result from pollination with compatible genotype pollen, is associated with larger berry mass (g). Decomposition of the total variance in fruit set shows that stem variation explains 65% to 79% of total variance in the fruit set. To a lesser extent, the field, year, and clone also explain the percent fruit set variation. Variation between stems may be due to variation in the number of flowers. Fruit set tends to decrease as the flower density increases, possibly due to the limitation of pollinators.

Laboratory experiments were conducted to determine larval movement of the spotted wing drosophila (Drosophila suzukii Matsumura). Movement of larvae outside of the wild blueberry fruit (Vaccinium angustifolium Alton) can occur after exhausting fruit food resources prior to completion of development or just prior to pupation. We found that when provided a choice larvae select moist compared to dry environments both in plastic arenas providing only filter paper for shelter and in a soil filled petri dishes. Movement was usually limited to less than 7.5 cm in the soil from a release point. An exponential decay model suggests that only 0.1% of a larval population will move as far as 17.5 cm. Results of our study suggest that while larvae move readily, they have minimal ability to avoid localized xeric soil micro-climatic conditions through movement. However, they will select less stressful moist soil environments.

We investigated the impact of an invasive ant species from Europe, Myrmica rubra (L.), on a myrmecochorous system (seeds dispersed by ants) in its invaded range in North America. We assessed: 1) how M. rubra process the myrmecochorous diapsores (seeds and elaiosome as a single dispersal unit transported by ants) in comparison with native ants; 2) its preference for common native and invasive diaspore species relative to native ants; 3) how far they disperse diaspores in the field; and 4) the diaspore removal rate by invertebrates and vertebrates in infested areas compared to noninvaded sites. Field experiments demonstrated higher diaspore removal rates over a 10-min and 24-h period by M. rubra compared to native ants. M. rubra's diaspore dispersal distance was 40% greater compared to native ants. In two of three laboratory studies and one field study, there was no significant difference between the seed species which M. rubra and native ants selected. Our data suggest no long-term deleterious effects of M. rubra's invasion on diaspore dispersal in the Maine plant community that is comprised of both native and invasive species. This implies that M. rubra benefits from the myrmechorous plant species' diaspores by increasing their dispersal range away from the parent plant and potentially reducing seed predation. However, it is not known whether the fact that the native ant fauna and M. rubra are attracted to the same plant species' diaspores creates a high level of competition between the ants with deleterious effects on the native ant community.

The high variability of wild (lowbush) blueberry plants in spatial and genetic structure, in combination with bee foraging behavior varying between species, and the complexity of these factors interacting over time and space, are major obstacles to understanding of pollination dynamics subject to environmental change. The bottom-up modeling paradigm provides an ideal approach to bridging the gap between known mechanisms of individual organisms and unknown spatial–temporal dynamics of pollination at the field scale. By linking empirical data to stochastically-based ecological process modeling, we present a spatially-explicit agent-based simulation model that enables exploration of how various factors, including plant spatial arrangements, outcrossing and self-pollination, bee species compositions and weather conditions, in isolation and combination, affect pollination efficiency throughout a blueberry bloom season. The firmly validated open-source model is a useful tool for hypothesis testing and theory development for wild blueberry pollination researches. Sensitivity analysis suggested that fruit set and resulting measures of productivity such as fruit mass and viable seeds per fruit were sensitive to parameterization of blueberry genotype or clone size and the amount of blueberry plant cover in a field. Fruit set due to pollen compatibility was sensitive to ovule number per flower and foraging bee density. Simulation experiments allowed us to compare bee pollination efficiencies at the bee taxon population level (honey bees, bumble bees, and native solitary bees), the effect of foraging distance from bee nest or colony site on fruit set, and test whether the mechanism of gametophytic self-incompatibility (pre- vs. post-zygotic decision making by the plant) in wild blueberry pollination at the field level matters in estimating yield.

Bee decline is a threat worldwide. An extension project was initiated to make the general public, industry, and municipalities aware of this problem. This study demonstrated pollinator habitat suitable for Maine farms by developing cooperation between the Maine wild blueberry industry and a regional commercial waste landfill. The reason for involving the landfill industry was to demonstrate and encourage non-farm enterprises to become involved in pollinator conservation. This project arose from previous research of ours on pollinator reservoirs in the Maine (USA) wild blueberry agro-ecosystem with the objectives of: (1) comparing three seed mixes, (2) providing demonstration areas where farmers and the general public can see such gardens, and (3) encouraging others to plant for pollinators. The methods involved planting two types of gardens in 2015, one that contained three different commercially available pollinator forage seed mixes, and one that contained shrubs and some perennials that are visited by pollinators early and late in the season, but that are not readily grown in a wildflower meadow. For all three seed mixes, at least some plant species produced flowers that were visited by bees, but there were also gaps in flowering and some species on which we saw few bees. We observed more bees coming to flowers of corn poppy, tall yellow clover, oxeye daisy, black-eyed Susan, anise hyssop, and bergamot. Ox-eye daisy and black-eyed Susan were not in any of the seed mixes but were allowed to grow among the sown plants. More than 600 people came through the booth or toured the gardens at four open houses in 2015 and 2016, and many people know of the project through presentations we have given. The stakeholders and public learned about bees and floral resources. Several municipalities and farmers have planted pollinator reservoirs since this project was initiated. Key words: Pollinator reservoirs, wildflower seed mix, demonstration, landfill, wild blueberry.

Increasing use of functional agrobiodiversity, organisms that help farmers, is crucial to improving resilience of conventional agriculture in industrial countries.Literature suggests acquiring local ecological knowledge on these species is a formidable barrier.The present study uses interview data to explore farmers' acquisition of local ecological knowledge concerning wild bees, as well as farmers' use and conservation of wild bees.Wild bees are important crop pollinators and an alternative or supplement to declining commercial honeybees.We found that high uncertainty over wild bees prompts risk aversion, slowing use and conservation.However, to acquire local ecological knowledge, farmers eschew time-consuming assessment and instead develop rules of thumb that mesh with and draw on their use of honeybees.These findings illustrate the complex way in which farmers adapt to the challenge of acquiring local ecological knowledge of functional agrobiodiversity in a conventional agricultural system.

Declines in wild and managed bee species richness and abundances have been observed throughout Europe and North America in recent decades. These declines have led to questions regarding pollination of wild and cultivated plants. In response to these concerns, efforts towards the conservation of pollinators have been initiated. Part of this conservation effort should be to provide the basic nutritional needs for bees. Nutrition plays one of the most important roles in bee growth, development, and reproduction. There is a large body of information regarding honey bee nutrition, whereas we lack nutritional information on native wild bees. Our knowledge of bumble bee nutritional needs has increased since the introduction of commercial rearing and sale of certain bumble bee species; however, there is still a lack of basic nutritional guidelines such as minimum dietary needs of proteins, amino acids, lipids, and sterols. The large difference in physiology and life history between honey bees and North American wild bees suggests that their nutritional requirements could be quite different.

Non-native honeybees historically have been managed for crop pollination, however, recent population declines draw attention to pollination services provided by native bees. We applied the InVEST Crop Pollination model, developed to predict native bee abundance from habitat resources, in Maine's wild blueberry crop landscape. We evaluated model performance with parameters informed by four approaches: 1) expert opinion; 2) sensitivity analysis.; 3) sensitivity analysis informed model optimization; and, 4) simulated annealing (uninformed) model optimization. Uninformed optimization improved model performance by 29% compared to expert opinion-informed model, while sensitivity-analysis informed optimization improved model performance by 54%. This suggests that expert opinion may not result in the best parameter values for the InVEST model. The proportion of deciduous/mixed forest within 2000 m of a blueberry field also reliably predicted native bee abundance in blueberry fields, however, the InVEST model provides an efficient tool to estimate bee abundance beyond the field perimeter. (C) 2016 Elsevier Ltd. All rights reserved.

Locally dispersing populations are generally favorably affected by increasing the scale of habitat heterogeneity because they can exploit contiguous patches of suitable habitat. Increasing the spatial scale of landscape disturbances (such as by applying a pesticide to control an unwanted species) drives down population density because of reasons including dispersal-limited recolonization and the resulting increase in temporal variability. Here, we examine how population density changes as the spatial scale of landscape disturbance increases: does it increase due to increases in spatial correlations in landscape habitat type, or does it decrease due to the various spatial and temporal effects of larger-scale disturbances? We use simulations, mean field approximations, pair approximations, landscape-improved pair approximations (LIPA), and block probabilities to investigate a model of a locally dispersing species on a dynamic landscape with spatiotemporally structured heterogeneous habitat. Pesticide is applied at a given spatial scale, leaving habitat unsuitable for some time before dissipating and allowing the habitat to revert to a suitable state. We found that increasing the spatial scale of disturbances (while keeping the overall disturbance rate fixed) can increase population density, but generally only when landscape turnover is slow relative to population dynamics and when the population is somewhat close to its extinction threshold. Applying control measures at larger spatial scales may allow them to be more effective with the same overall treatment rate. The optimal spatial strategy for applying disturbances depends on both habitat availability as well as the turnover rate of the control measure being used. For the large-scale habitat dynamics in our model, it is possible to analytically calculate spatial correlations in habitat types over arbitrary scales. However, including exact habitat correlations at the triplet scale but approximating population correlations at that scale still neglects information needed to accurately predict simulation results, showing that larger-scale correlations in the population distribution have an important effect on dynamics.

Wildlife as a source of microbial contamination is a food safety concern. Deer feces (scat) have been determined as a point source for Escherichia coli O157:H7 contamination of fresh produce. The ecological role of the scooped scarab (Onthophagus hecate (Panzer)), a generalist dung beetle species common in Maine blueberry fields, was explored as a biological control agent and alternatively as a pathogen vector between deer scat and food. A large-scale field survey of wildlife scat indicated that pathogenic E. coli O157:H7 was present, albeit at a low prevalence (1.9% of samples, n = 318), in the Maine lowbush blueberry agroecosystem. A manipulative field experiment verified that, should contact occur between deer scat and blueberry plants and fruit during the summer, contamination with E. coli O157:H7 can occur and persist for more than 72 h. For both the positive control and an experimental scat inoculation treatment, the levels of the bacterial population decreased over time, but at different rates (treatment x time interaction: F (1.9,18.8) = 358.486, P < 0.0001). The positive control inoculation, which resulted in a higher initial E. coli level on fruit, decayed at a faster rate than inoculation of fruit via scat in the experimental treatment. We conducted 2 laboratory studies to elucidate aspects of dung beetle feeding ecology as it relates to suppression of E. coli O157:H7 from deer scat to lowbush blueberry fruit. In both experiments, dung beetles buried the same amount of scat whether or not the scat was inoculated with the pathogen (F(1,6) = 0.001; P = 0.999 and (F (2,17) = 4.10, P = 0.147). Beetles feeding on E. coli inoculated deer scat were not found to vector the pathogen to fruit. In two studies, beetles lowered the amount of pathogenic E. coli persisting in soils compared to soils without beetles (F (2,9) = 7.757; P = 0.05 and F (2,17) = 8.0621, P = 0.004). Our study suggests that the dung beetle species, Onthophagus hecate, has the potential to contribute to the suppression of E. coli O157:H7 in agricultural landscapes.

This study investigated bee visitation on 10 agricultural crops grown on diverse small farms in Tennessee to determine the abundance of native bees and honey bees and the partitioning of visitation among crops. Summaries for each crop are used to generate mean proportions of bee visitation by categories of bees. This shows that native bee visits often occur as frequently, or in greater proportions than non-native honey bee visits. Visitation across multiple crops is then analyzed together with nonmetric multidimensional scaling to show how communities of bees that provide crop pollination change depending on the crop. Within squash and pumpkin plantings, continuous and discrete factors, such as "time of day" and "organic practices," further explain shifts in the community composition of flower visitors. Results from this study show that native bees frequently visit flowers on various crops, indicating that they are likely contributing to pollination services in addition to honey bees. Furthermore, the community of bees visiting flowers changes based on crop type, phenology, and spatial-temporal factors. Results suggest that developing pollinator conservation for farms that grow a wide variety of crops will likely require multiple conservation strategies. Farms that concentrate on a single crop may be able to tailor conservation practices toward the most important bees in their system and geographic locale.

Beekeepers who use honey bees (Apis mellifera L.) for crop pollination services, or have colonies making honey on or in close proximity to agricultural crops, are concerned about the reductions of colony foragers and ultimate weakening of their colonies. Pesticide exposure is a potential factor in the loss of foragers. During 2009-2010, we assessed changes in the field force populations of 9-10 colonies at one location per crop on each of the eight crops by counting departing foragers leaving colonies at regular intervals during the respective crop blooming periods. The number of frames of adult bees was counted before and after bloom period. For pesticide analysis, we collected dead and dying bees near the hives, returning foragers, crop flowers, trapped pollen, and corn-flowers associated with the cotton crop. The number of departing foragers changed over time in all crops except almonds; general patterns in foraging activity included declines (cotton), noticeable peaks and declines (alfalfa, blueberries, cotton, corn, and pumpkins), and increases (apples and cantaloupes). The number of adult bee frames increased or remained stable in all crops except alfalfa and cotton. A total of 53 different pesticide residues were identified in samples collected across eight crops. Hazard quotients (HQ) were calculated for the combined residues for all crop-associated samples and separately for samples of dead and dying bees. A decrease in the number of departing foragers in cotton was one of the most substantial crop-associated impacts and presented the highest pesticide risk estimated by a summed pesticide residue HQ.