The ideal-free distribution and central-place foraging are important ecological models that can explain the distribution of foraging organisms in their environment. However, this model ignores distance-based foraging costs from a central place (hive, nest), whereas central-place foraging ignores competition. Different foraging currencies and cooperation between foragers also create different optimal distributions of foragers, but are limited to a simple two-patch model. We present a hybrid model of the ideal-free distribution that uses realistic competitive effects although accounting for distance-based foraging, and test it using honey bees (Apis mellifera L.) foraging in canola fields (Brassica napus L.). Our simulations show that foragers maximizing efficiency $(energyprofits÷losses)$ prioritize distance to their aggregation more than those maximizing net-rate $(energyprofits÷time),$ and that social foragers move to more distant patches to maximize group benefits, meaning that social foragers do not approach an ideal-free distribution. Simulated efficiency-maximizers had a hump-shaped relationship of trip times with distance, spending shorter amounts of time in both nearby and far-away patches. Canola fields were far more attractive to simulated foragers than semi-natural areas, suggesting limited foraging on semi-natural lands during the bloom period of canola. Finally, we found that the observed distribution of honey bees in canola fields most closely resembled the optimal distribution of solitary efficiency-maximizers. Our model has both theoretical and practical uses, as it allows us to model central-place forager distributions in complex landscapes as well as providing information on appropriate hive stocking rates for agricultural pollination.

Plasmodiophora brassicae Wor. is a soilborne parasite causing clubroot of canola (Brassica napus L.), a serious disease managed mostly by planting clubroot-resistant (CR) cultivars. Recently, new pathotypes of P. brassicae have emerged that overcome resistance, highlighting the need for a greater understanding of resistance stewardship and an integrated approach to clubroot management. Replicated field experiments were conducted in Edmonton, AB, in 2018 and 2019, to evaluate the effect of lime application and weed management on clubroot severity, crop yield and various growth parameters in clubroot-susceptible (CS) and CR canola cultivars. P. brassicae resting spore densities were also monitored by quantitative PCR for each treatment. When hydrated lime was applied to increase the soil pH from initial values of 5.2–5.5 to 7.2, clubroot severity decreased by 34–36% in the CS canola cultivar, while seed yield increased by 70–98%. The application of hydrated lime also resulted in resting spore densities that were 48–80% lower, relative to untreated controls, in plots where the CS cultivar was grown. Lime application or management of weeds did not significantly affect spore densities in plots with the CR cultivar. The results from the field trial suggest that the application of hydrated lime may be a useful strategy to manage clubroot, when used in combination with genetic resistance to reduce disease pressure.

The Oregon Bee Atlas is a new volunteer-led effort to characterize the bee fauna of Oregon State by collecting, preparing and databasing specimens of wild bee species and their plant host records. In 2019 volunteers submitted 25,022 bee specimens across all Oregon counties, representing 224 unique bee species and 45 unique bee genera. Specimens were collected from a total of 352 unique flowering plant genera, resulting in the largest contemporary state-level database of bee-host plant interactions. Volunteers produced valuable occurrence records for species poorly known for the state, and species of conservation concern. The 2019 data builds on the efforts of 2018 in demonstrating the power of a specimen-focused, volunteer wild bee survey.

The colonies of honey bees are mostly sessile organisms. Consequently, the type of nest boxes that beekeepers provide to their bees should impact a colony’s ability to maintain homeostasis, which is a key determinant of performance and fitness. Here, we used European honey bees (Apis mellifera) and provided them with two hive setups widely used and known as Langstroth and Warré. We compared colony performance in a Mediterranean climate for five months from late spring to early autumn, which covered the most active time of bees and included periods of heat and drought. We found that irrespective of hive type or season, honey bees kept hive temperature and humidity within a remarkably narrow range. Nevertheless, the hive type impacted the daily fluctuations in temperature and humidity. In Warré hives, where bees have more autonomy to build and maintain their combs, we found that bees were able to reduce daily fluctuations in temperature and humidity and kept both measures closer to the overall average. This increase in colony homeostasis found in Warré hives negatively correlated with other hive performance indicators, such as immunocompetence. We conclude that different hive types affect key areas, such as the central part of the colony with frames of developing brood or the queen, which are the most susceptible individuals. This implies that climatic changes resulting in extreme weather events are expected to impact colony performance and fitness, especially in non-managed honey bees that are limited by available nesting sites. For managed bees, adaptations to existing hive setups could be provided to help bees minimize the effects of abiotic stress.