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Browsing by Author "Steele, Taylor N."

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    Apple orchards feed and contaminate bees during, but even more so after bloom
    Steele, Taylor N. (Virginia Tech, 2021-11-16)
    Honey bees, Apis mellifera Linn., provide vital economic and ecological services via pollination while concurrently facing multiple interconnected stressors impacting their health. Many crops like apples, peaches, and cherries that add diversity and nutrition to our diet are wholly or partially dependent upon the pollination services of insects. Orchard crops are self-incompatible and commonly regarded as crops reliant on the pollination services of insects, and while previous studies have focused on the impact of bees to orchard crops during bloom, fewer studies have examined the reciprocal relationship of the orchards on honey bees, particularly across the entire foraging season. Here we investigated the foraging dynamics of honey bees in an orchard crop environment in Northern Virginia, United States. We decoded, mapped, and analyzed 3,710 waggle dances, which communicate the location of a valuable resource in the environment, for two full foraging seasons (April-October, 2018-2019), and, concurrent to the dance filming, collected pollen from returning foragers. We found that bees forage locally the majority of the time (< 2 km) throughout the season, with some long-range distances occurring in May after bloom (both 2018 and 2019) and in fall (2019). The shortest communicated median distances (0.50 km and 0.53 km), indicating abundant food availability, occurred during September in both years, paralleling the bloom of an important late season resource, goldenrod (Solidago). We determined, through plotting and analyzing the communicated forage locations and from the collected pollen from returning foragers, that honey bees forage more within apple orchards after the bloom (29.4% and 28.5% foraging) compared to during bloom (18.6% and 21.4% foraging) on the understory of clover and plantain. This post bloom foraging also exposes honey bees to the highest concentration of pesticides across the entire foraging season (2322.89 ppb pesticides versus 181.8 during bloom, 569.84 in late summer, and 246.24 in fall). Therefore, post bloom apple orchards supply an abundance of forage, but also the highest risk of pesticide exposure, which may have important implications for management decisions of bees in orchards.
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    Apple orchards feed honey bees during, but even more so after, bloom
    Steele, Taylor N.; Schürch, Roger; Ohlinger, Bradley D.; Couvillon, Margaret J. (Wiley, 2022-09-01)
    Many of the fruits that add diversity and nutrition to our diet are wholly or partially dependent upon flower-visiting insects. For example, apples (Malus spp.) are self-incompatible and therefore rely on insect pollinators for fruit development and seed production. Honey bees (Apis mellifera) are often migrated into these orchards when the apples are in bloom. While previous studies have focused on the impact of honey bees to fruit orchards, fewer studies have examined the reciprocal relationship of the orchards to honey bees, particularly if the bees are in the orchard for the entire foraging season, not just during bloom. Here we investigated the foraging dynamics of honey bees in apple orchards in Virginia for two full foraging seasons (April–October, 2018–2019). We decoded, mapped, and analyzed the waggle dances (n = 3710) made by returning foragers, which communicate the distance and direction from the hive to valuable resources, usually nectar or pollen. We found that bees foraged locally at <2 km throughout the season in both 2018 and 2019, with some long-range recruitment of up to 11 km. Contrary to our expectations, apple blooms did not drive honey bee foraging. We determined in our calculations of percent (%) foraging that honey bees recruit more to the apple orchards after the bloom than during the bloom (29.4% vs. 18.6% in 2018 and 28.5% vs. 21.4% in 2019, respectively). Interestingly, honey bees recruited more to forests while the apples bloomed (36.9% and 25.7% in 2018 and 2019, respectively). Lastly, our odds ratio analysis, which includes a distance correction, indicates the honey bees were more than twice as likely to recruit to apple orchards in June, which is after the bloom, than in April or May, which is during the bloom. Our ground truthing revealed that post-bloom apple orchards provided foraging opportunities on the growing understory of red and white clover (Trifolium spp.) and plantain (Plantago spp.). These data might therefore have important implications for best management practice decisions for bees located in fruit orchards.
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    Dance-communicated distances support nectar foraging as a supply-driven system
    Ohlinger, Bradley D.; Schürch, Roger; Silliman, Mary R.; Steele, Taylor N.; Couvillon, Margaret J. (The Royal Society, 2022-08-31)
    Much like human consumers, honeybees adjust their behaviours based on resources' supply and demand. For both, interactions occur in fluctuating conditions. Honeybees weigh the cost of flight against the benefit of nectar and pollen, which are nutritionally distinct resources that serve different purposes: bees collect nectar continuously to build large honey stores for overwintering, but they collect pollen intermittently to build modest stores for brood production periods. Therefore, nectar foraging can be considered a supply-driven process, whereas pollen foraging is demand-driven. Here we compared the foraging distances, communicated by waggle dances and serving as a proxy for cost, for nectar and pollen in three ecologically distinct landscapes in Virginia. We found that honeybees foraged for nectar at distances 14% further than for pollen across all three sites (n = 6224 dances, p < 0.001). Specific temporal dynamics reveal that monthly nectar foraging occurs at greater distances compared with pollen foraging 85% of the time. Our results strongly suggest that honeybee foraging cost dynamics are consistent with nectar supply-driven and pollen demand-driven processes.