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Solitary bees are in constant decline due to climate change, pesticide toxicity, and habitat loss. Provision of nesting sites is an important conservation strategy. Various factors affect bee nesting, including parasitism, entrance orientation, nesting substrate type, and diameter. This study explored the impact of nesting substrate, cavity diameter, and entrance orientation on solitary bee nesting preferences. Additionally, it investigated the influence of landscape type and seasonality on bee nesting efficiency which is the ability of a bee to successfully establish nest. Trap nests were placed at eight locations, representing five landscapes (forest, desert, agriculture, peri-urban, and urban). These trap nests had five different nesting substrates (bamboo reeds, wooden blocks, wooden logs, mud blocks, and paper tubes). At each location, four traps were set in all directions. The results showed maximum cavity occupation in south-facing nests. Peri-urban landscapes were the most favored for nesting, followed by forests. Solitary bees primarily preferred bamboo reeds for nesting, with peak occupation from April to June. Bees favored cavities with 6- and 8-mm entrance diameters, while wasps occupied smaller diameters (< 5 mm). Overall, bee species occupied fewer nests compared to parasitic wasps. Future research should explore brood chamber numbers and species-specific nesting preferences for bees, along with the impact of cavity microclimate on bee growth. [ABSTRACT FROM AUTHOR]

Selenium (Se) is an essential nutrient for both plants and animals and is usually provided as a supplement to livestock. Se bioaccumulation promotes plant growth by enhancing the accumulation of organic solutes and the activation of antioxidant system. In animals, the Se supplements reduce the chances of mastitis and white muscle disease, and improve the immunity, health, and reproduction, particularly in lactating dairy cows. Therefore, the enrichment or biofortification of fodder crops with Se may improve the nutritional quality of forages and thereby reduce malnutrition in cattle. However, Se hyper-accumulation in plants or plant parts can cause direct toxic effects on insects especially bees. Berseem is a highly cross-pollinated fodder crop that attracts a large number of pollinators. However, little or no reports are available regarding the effects of Se biofortification on the foraging behavior of pollinators in berseem. Therefore, the current study was planned to evaluate the effect of exogenous application of Se on the foraging behavior of native pollinators visiting the berseem crop. Five different doses of Se were applied to evaluate its effect on abundance, foraging behavior (visit duration and visitation rate), and single-visit efficacy of native pollinators that may affect berseem seed yield. Our results showed maximum abundance of pollinators in plants supplemented with low Se level, i.e., 5 g ha−1 while the minimum abundance was observed at high Se doses (15 and 20 g ha−1). Also, the seed yield attributes, i.e., the number of seeds per head, seed weight per head, 1000 seed weight, were the highest in plants treated with a low dose of Se, whereas the seed yield of berseem decreased with an increase in Se concentrations. Hence, our study provides evidence that high doses of Se negatively affect the foraging behavior of pollinators (visitation rate and visit duration) in plants. We conclude that the application of moderate Se dose positively influences the pollination ecology of berseem, consequently improving seed yield. Highlights: Selenium (Se) is essential for animals and beneficial for plants and may become toxic at high level. Se is delivered to the environment due to agriculture. Se toxicity affected berseem growth and considerably reduced the seed yield. High dose of Se reduced the abundance of pollinators and negatively affected their foraging behavior. [ABSTRACT FROM AUTHOR]

To discover the pollinator community of canola ( Brassica napus L.) and the best pollinators for canola production, an experiment was performed at the research farm of Bahauddin Zakariya University, Multan, Pakistan. The insect pollinator community was composed of 35 species in 3 orders and 14 families. Most of the bees (Hymenoptera) and a butterfly species (Lepidoptera) foraged for nectar, whereas all the flies (Diptera) foraged either for pollen or both nectar and pollen. Eight major pollinators were tested for their pollination efficiency. The nectar-robbing behavior of many species made it difficult to judge the efficiency of an insect on the basis of visitation rate and stay time; therefore, the amounts of pollen deposited and pollen harvested per visit were also measured. The single visit efficiency in terms of the number of seeds per pod revealed that Apis dorsata, A. florea, and Halictus sp. were superior for canola pollination, having Spears' values of 1.62, 1.55 and 1.73, respectively. With the increase in the number of seeds per pod, seed weight per pod also increased, confirming the importance of these three pollinator species in canola production. [ABSTRACT FROM AUTHOR]