The blue orchard bee, Osmia lignaria Say (Hymenoptera: Megachilidae), is among the most widely studied native solitary bee species in the United States. Blue Orchard Bees are larger than Hornedfaced bees and will nest in a hole diameter as small as 5/16th of an inch without changing the sex ratio of the offspring. Ongoing drought conditions may explain lower bee reproduction in 2015. The lack of differences in yield is likely a consequence of local saturation of pollinator services supplied by managed honey bees throughout experimental orchards, such that no additive benefit of managed O. lignaria releases were measurable. Osmia lignaria is native to North America and split into two subspecies: O. lignaria propinqua which is found west of the 100th meridian, and O. lignaria lignaria which is found east of the 100th meridian (Guisse and Miller 2011). Poorer overall nesting could bias sex ratios toward females, since female eggs are typically laid first in the nesting tunnel (Bosch & Kemp, 2001). The cause of this behavior is unknown but may reflect the quality/condition of the bees that were released, environmental factors, pesticide use, or changes to orchard management. Osmia lignaria were observed frequently in the wildflower plantings throughout 2015 and 2016 during and after almond bloom (Figure 3). Nest boxes were made of dark blue corrugated plastic boxes (21.5 × 20 × 25.5 cm), each housing one-hundred 7 × 152 mm cardboard nesting tunnels lined with waxed paper straws. The material used for the cell can be clay, mud, grit, or chewed plant tissue. Nests were first sampled at the onset of petal fall on 8 March 2016, at which time all completed, “plugged” nests were painted with blue acrylic paint over the terminal mud plug throughout the selected rows. One limb from each tree was marked and assessed for all three measurements, although the criteria for limb selection varied slightly between years. In 2016, 80% of released bees were recovered as progeny. Tukey's multiple comparisons were conducted to distinguish differences between zones. Many of the significant trends observed from progeny outcomes were not reproducible between years. It is also critical to remember that although nesting over time did not vary between A1 and A2, significantly more viable cells were recovered from A1, which had the closest proximity to the plantings. Such dry weather likely restricted O. lignaria access to mud, which is required of females for nest construction and reproduction. Within a few days of mating, the female has selected a nest site and has begun to visit flowers to gather pollen and nectar for her nests; many trips are needed to complete a pollen/nectar provision mass. Because of the humidity requirements of the two subspecies they cannot be moved far outside of their natural ranges. They are immune from acarine and Varroa mites, but have their own unique parasites, pests, and diseases. Osmia (Osmia) lignaria are dark metallic blue bees. Proceedings of the Royal Society B: Biological Sciences, United States Department of Agriculture Economic Research Service Situation and Outlook Report. The pollen composition of provisions from completed long‐distance tunnels was also determined using these same methods. Then, they seal the entrance to the hole with a thicker mud wall. We conclude that planting and maintaining wildflowers is a promising strategy for integrating O. lignaria pollination into existing orchards, particularly in landscapes with limited alternative floral resources. Managed, supplementary wildflower plantings may promote O. lignaria reproduction in California almond orchards. The thorax has intermixed pale and black hair on the scutum and primarily black hair on the episternum. Afterward, they build a little mud wall and start gathering food for the subsequent cell. The males typically remain near the nests waiting for the females, and some are known to actively extract females from their cocoons. Honey bee hives (2 deeps per hive) were placed along orchard edges on pallets (four hives per pallet) to achieve the desired stocking density; hives were owned and managed directly by contracted beekeepers. To date, their successful implementation in agriculture has been limited by poor recovery of … While significant, no meaningful trend in developmental mortality could be determined in 2015 by zone (Table S3, Figure 5e). The nesting habits of many Osmia species lend themselves to easy cultivation, and a number of Osmia species are commercially propagated in different parts of the world to improve pollination in fruit and nut production. TypoMissing or incorrect metadataQuality: PDF, figure, table, or data qualityDownload issuesAbusive behaviorResearch misconductOther issue not listed above. Males do not have reliable characters to distinguish between the subspecies (Rust 1974). The blue orchard bee, Osmia lignaria (Say) (Hymenoptera: Megachilidae), is an alternative managed pollinator of rosaceous tree-crops, and potentially could be used for blueberry (Ericaceae) pollination. If you do not receive an email within 10 minutes, your email address may not be registered, Bees were stocked in OL+ orchard plots at a density of 625 females/ha, per the recommendation of Bosch & Kemp (2001). Pollen composition was determined only from the terminal (most recently completed) provision of each individual nest sampled. Each year was analyzed separately. These updates will appear in your home dashboard each time you visit PeerJ. Almond blossoms are only available to foraging bees for 2–3 weeks of the year, which does not fully accommodate the 4–6‐week life span of foraging O. lignaria. We propose that, despite the low reproduction obtained in 2018, tart cherry orchards may serve as an appropriate avenue for future open field, managed O. lignaria propagation efforts, while also providing local pollination services to growers. Recent studies have and continue to identify the crops and geographic regions in which managed O. lignaria populations best perform. These orchard regions, or “zones,” varied in their proximity to the wildflower plantings and orchard edges across the three replicates, ranging from 80 m (zone A1) to 580 m (zone C3) (Figure 1; Table 2). Working off-campus? Osmia lignaria are cavity-nesters and will reside gregariously in artificially-supplied hollow cavities such as reeds, corrugated wood blocks or cardboard tunnels (Bosch & Kemp, 2001). From the 2016 analysis of O. lignaria pollen provisions, we confirmed that nesting females collected pollen from the wildflower plantings from up to 800 m away. This study evaluated the implementation of O. lignaria co-pollination with honey bees in central Utah commercial tart cherry orchards during 2017 and 2018 bloom. Starting 1 week after their release in the orchards, we recorded nest completion by taking photographs of all nest boxes every 5–7 days until late March (both years). Collinsia heterophylla was observed infrequently in pollen provisions, and no E. californica grains were identified in any sampled provisions. To serve as a control, three paired 1.2 ha plots were additionally selected, where only honey bees (2.5 hive/ha; ‘OL-’) were available for pollination (a randomized complete block design). From these results, we are not able to gauge the effectiveness of O. lignaria as cherry pollinators when no adjustments to honey bee stocking density are made. Despite notable differences in the geographic distances separating “edge” zones A1 (80 m) and A2 (410 m) from the wildflower plantings, no significant difference in nesting was determined for 2015 or 2016 (Table S2). However, unlike with almonds, tart cherries are self-pollinating, such that insect pollination is not required for trees to bear fruit. Pollen counts that favored almond pollen were concentrated in orchard interiors and during peak bloom.  Commercial pollinators include O. lignaria, O. bicornis, O. cornuta, O. cornifrons, O. ribifloris, and O. californica. At the proximal end of each selected limb, the limb circumference was measured (cm2) to allow for fruit/limb cross-sectional area calculations. Unidentified nests were constructed at the remaining sites. Once they have a food store that is big enough, they lay an egg on top of this mass and seal-off the chamber or cell. At the same time, floral plot visitation data confirm that O. lignaria continued to access the wildflower plantings beyond almond bloom during both years. For photographs with fewer than 125 pollen grains, a second photograph was recorded from elsewhere on the slide, and all grains were counted and identified within that photograph as well. This would also confer the greatest benefit to wild ecosystems, as it would decrease the industry's reliance on harvesting O. lignaria cocoons from native wildlands (Tepedino & Nielson, 2017), where consequential ecological impacts are largely unknown. Completed nests were discernable in photographs by the presence of a mud plug at the terminal end of nesting tunnels (Figure 2b). 2000; Bosch et al. This decision was made in part due to the 2018 removal and subsequent replanting of tart cherry acreage after the 2017 season. If they are, they disperse from where they emerged to try and find the right nesting habitat and they won't re-nest in your nests. Consequently, it has become increasingly more difficult for commercial beekeepers to meet the pollination demands of the industry (Aizen & Harder, 2009; Seitz et al., 2016; Ward, Whyte, & James, 2010), which is compounded by persistent stressors impacting honeybee health and survival (vanEngelsdorp et al., 2009). No alternative floral resources were added for foraging adults in the orchards. The California almond (Prunus dulcis Mill.)  Commonly, this means in hollow twigs but can be in abandoned nests of wood-boring beetles or carpenter bees, in snail shells, under bark, or in other small protected cavities. The resulting images provided a full census of bee reproduction and progeny outcomes. Further, wildflower plots do not need to be large to benefit nesting O. lignaria and other bees. Across all zones, the greatest rate of O. lignaria nest completion was observed consistently between 5 March and 12 March in 2015 and between 26 February and 1 March in 2016 (Figure 4). With a stocking rate of 750 O. lignaria females per hectare required for almond pollination, we must identify management practices that favor the highest possible retention of nesting females and rates of in‐orchard bee propagation to reduce annual pollination costs. However, in 2016, zones geographically closest to the wildflower plantings experienced significantly less proportional developmental failure than progeny in zones further away (Table S3, Figure 5e). The blue orchard bee, Osmia lignaria (Say), is a commercially available native bee that can be employed as a copollinator with, or alternative pollinator to, honeybees in orchards. Osmia lignaria visitation to all plots wereas recorded along two 50‐m transects at each time point, using methods described in Lundin et al. Osmia lignaria were left to mate and provision nests in the OL+ treatments for four to five weeks until just before the first scheduled post-bloom fungicide spray (however, O. lignaria populations were exposed to a single nutritional spray during late May in 2017 and 2018). You can add specific subject areas through your profile settings. The blue orchard bee or Osmia lignaria, is prized for its efficiency pollinating fruit trees and is one of the few native pollinators that is managed in agriculture. pollen was found in sampled provisions closest to the wildflower plantings, and at all distances, O. lignaria‐foraging preferences shifted dramatically in favor of Phacelia spp. Shoemaker (1928) reports the fruit setting rate of Montmorency trees to be approximately 6% in the absence of cross-pollination and 25–30% with hand- or insect-pollination. Osmia lignaria is a commercially available, native solitary bee species recognized for its propensity to forage upon and pollinate tree fruit crops such as apple, almond and cherry. Each nest box was hung from a tree branch (ca. Eine Verbreitungskarte gibt Peters (1978).