Copyedited by: OUP

Annals of the Entomological Society of America, XX(X), 2018, 1–6 doi: 10.1093/aesa/say028 Research Research

Pollen Use by (: ) in Highbush Blueberry Fields

Mario S. Pinilla-Gallego1,2,4 and Rufus Isaacs1,3

1Department of Entomology, Michigan State University, 578 Wilson Road, East Lansing, MI 48824, 2Applied Ecology Department, North Carolina State University, Campus Box 7617, 100 Brooks Avenue, Raleigh, NC 27607-7150, 3Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, 103 Giltner Hall, 293 Farm Lane, East Lansing, MI 48824, 4Corresponding author, e-mail: [email protected]

Subject Editor: Allen Szalanski

Received 8 May 2018; Editorial decision 14 July 2018

Abstract The blue orchard , Osmia lignaria (Say) (Hymenoptera: Megachilidae), is an alternative managed pollinator of rosaceous tree-crops, and potentially could be used for blueberry () pollination. However, the floral preferences of this species for other types of flowers could prevent them from visiting blueberry flowers when alternative forage is available. To evaluate O. lignaria suitability for pollination of commercial blueberries in Michigan, we identified the main pollen sources in scopal loads and brood provisions, and determined the contribution of blueberry pollen to pollen collected by females nesting inside or at the border of a large blueberry field. Across two bloom seasons, we found that blueberry pollen was not the most abundant pollen type in either the scopal loads (≈6%) or the brood provisions (13–20%). Black cherry (Prunus serotina, Rosaceae), white clover (Trifolium repens, Fabaceae), and red clover (Trifolium pratese, Fabaceae) were the most abundant pollen types in the brood provisions. While shelter location (inside or at the border of the field) had an influence on the use of some of these plants, it did not affect the use of blueberry pollen. Our results indicate that in these field conditions,O. lignaria visit other plants rather than blueberries as a pollen source, making it poorly suited as an alternative managed pollinator for this specific crop.

Key words: blue orchard bee, , alternative managed bee, palynology, Vaccinium corymbosum

Animal pollination is required by many crops to achieve profitable by mud partitions, what give them the name of ‘mason ’ (Mader yields (Klein et al. 2007), with bees (Hymenoptera: Apoidea) being et al. 2010). Females usually build one cell per day (Phillips and the most important pollinators (Gallai et al. 2009, Garibaldi et al. Klostermeyer 1978), requiring 14 to 35 pollen and nectar foraging 2011, Nogué et al. 2016). European honey bees (Apis mellifera trips to provide one cell, and 12 trips are required to build each mud L.) (Hymenoptera: Apidae) are the most commonly used commercial partition (Torchio 1989). Nests usually have 4–12 cells and a female pollinator; however, in the last few decades beekeepers have faced can build 1–6 nests during the nesting period (Medler 1967, Mader increasing challenges to their management (VanEngelsdorp et al. et al. 2010). 2008, Potts et al. 2010, VanEngelsdorp and Meixner 2010), high- Highbush blueberry (Vaccinium corymbosum) requires lighting the importance of finding alternative pollinators for crops pollination for profitable yields (Mackenzie 1997, Ritzinger and (Garibaldi et al. 2013). The blue orchard bee, Osmia lignaria (Say) Lyrene 1999). The flowers produce pollen and nectar, and have pori- (Hymenoptera: Megachilidae), is an alternative managed pollinator, cidal anthers that release pollen by mechanical stimulus (McGregor with a higher pollination efficiency than honey bees for important 1976). For this reason, bees that can buzz-pollinate (e.g., bumble- crops such as apple, cherry, pear, and plum (Torchio 1982, Bosch bees) are more efficient at pollinating blueberries (Javorek et al. and Kemp 1999, Mader et al. 2010, Sheffield 2014). This is due to 2002, Ratti et al. 2008) than those that do not use this behavior, their efficient foraging behavior and strong preference for rosaceous such as honey bees. However, honey bee hives are usually placed in plants (Monzón et al. 2004, Matsumoto et al. 2009). the fields because the high number of visits to the flowers compen- O. lignaria is a univoltine, solitary, cavity-nesting bee (Levin sates for the lack of specialization in behavior (Dedej and Delaplane 1966). They nest in cavities in wood or hollow reeds, building a 2003). series of brood cells that are provisioned with a mix of pollen and Several species of Osmia have been tested for their ability to nectar (Bosch and Kemp 2002, Cane et al. 2007). Cells are separated pollinate blueberry. Osmia ribifloris (Cockerell) (Hymenoptera:

© The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. 1 All rights reserved. For permissions, please e-mail: [email protected].

Downloaded from https://academic.oup.com/aesa/advance-article-abstract/doi/10.1093/aesa/say028/5061887 by D H Hill Library - Acquis S user on 31 July 2018 Copyedited by: OUP

Annals of the Entomological Society of America, 2018, Vol. 00, No. 00

Megachilidae) is considered to be specialized on blueberries, and At each location we placed a shelter consisting of pine plywood its nest provisions can be made almost exclusively with blueberry boxes (26 × 28 × 28 cm) with an open face. Each shelter contained pollen (Torchio 1990, Stubbs et al. 1994). Controlled experiments 50 stems (bamboo and natural reeds), approximately 15 cm long (greenhouse or cage) with the same species show that it is effective with an inside diameter of 7–10 mm. Shelters at the border of the at depositing pollen on the stigmas, in some cases achieving the same field were placed facing into the field, while shelters in the field were level of pollination as bumblebees (Bombus spp. Hymenoptera: placed with the open face parallel to the orientation of the plant Apidae) (Sampson and Cane 2000, Sampson et al. 2004). Species rows. Shelters remained in the field between 10 May 2016 and 8 that normally prefer Rosaceous trees (e.g., O. lignaria and Osmia June 2016, and between 6 May 2017 and 13 June 2017, correspond- cornifrons (Radoszkowski) (Hymenoptera: Megachilidae)) have ing to the start and end of blueberry bloom at the site. been found to also be efficient at depositing blueberry pollen on A small emergence box containing O. lignaria loose cocoons was the stigmas (Dogterom 1999, West and McCutcheon 2009), but the placed in each shelter at the start of bloom. In 2016 each emerg- floral preferences that O. lignaria show for rosaceous plants can ing box contained 30 female and 45 male cocoons collected in prevent them from visiting blueberry flowers in the field (Sampson September 2015 from trap nests located at Michigan State University et al. 2009). This is supported by reports that indicate that most of (MSU) campus in East Lansing, MI. In 2017 bees were from trap the pollen found in O. lignaria nests located in agricultural environ- nests located in Fennville, MI, and due to lower availability, each box ments comes from orchard crops (Torchio 1982, Bosch et al. 2006, contained 20 female and 35 male cocoons. Sheffield et al. 2008). Given this background, it is important to explore the pollen use Pollen Samples From Bee Nests by O. lignaria in open field experiments in large areas of blueberry To identify nests built by O. lignaria, we performed a 15-min inspec- production, to determine whether this bee species can be used as an tion of the shelters once per week, recording the location of tubes effective alternative managed pollinator of blueberry, or whether the where O. lignaria was nesting. In 2016, during these sampling peri- promising results described above are relevant only to greenhouse or ods we captured female O. lignaria returning to the nests with pollen caged settings. This is important because of the growing interest in the loads on the scopa. We immobilized them with cold, removed the use of alternative pollinators among growers who are experiencing pollen load with dissecting needles, and stored the pollen in 1.5-ml rising costs for honey bee rentals, and increased variability in spring centrifuge tubes. Bees were released after they recovered from the weather that creates unsuitable conditions for honey bee flight. To cold. On 8 June 2016 and 13 June 2017, when blueberry bloom address this question, the objectives of this study were to 1) determine was complete, tubes occupied by O. lignaria were brought back to the contribution of blueberry pollen to O. lignaria brood provision the laboratory and kept in cold storage (−23°C) until processing. All in a commercial field, 2) determine the plant species used as pollen nests were opened and the whole pollen provision from individual resources by O. lignaria in this setting, and 3) assess whether nest brood cells was collected and stored in individual tubes. The contri- location in the field influences the pollen sources used by O. lignaria. bution of blueberry pollen to mass provisions can be used as a proxy for pollination in blueberry, given than nectar-harvesting visits to flowers only result in pollination in 25% of the cases, in comparison Methods with 85% when bees actively harvest pollen (Javorek et al. 2002). Study System We recorded the total number of nests completed by O. lignaria in This research was carried out during the 2016 and 2017 growing each location and the number of cells per nest. seasons, at a large commercial farm in Pullman, MI (42° 28′ 40.42″ N 86° 1′ 38.50″ W). The farm has an area of approximately 63 ha Plant Richness and Pollen Library dedicated to highbush blueberry (V. corymbosum), with nine varie- To sample blooming-plant richness around each shelter, once per week ties grown, including Jersey, Bluecrop and Nelson, which occupy the we established two transects of 100 × 3 m at each shelter location. In largest area (33.1, 24.8, and 14% respectively). The farm uses con- locations at the border of the field, transects were done in north and ventional management practices, including insecticide and fungicide south directions. For locations inside the field, transects followed the applications. The only insecticide applied during bloom period was orientation of the blueberry rows. The first time each plant species was methoxyfenozide, thought the fungicides chlorothalonil, captan, and observed, a reference specimen was collected and pressed for further metaconazole were also applied. Periodic mowing occurred approxi- identification using Petrides (1972), Newcomb (1977), and Peterson mately every 2 wk in and around the field. However, weeds and wild and McKenny (1996). Additionally, several flower buds were collected plants grew in the drainage ditches around the edges of the field, and from each plant for pollen extraction. If flower buds were not availa- in the deciduous forest that surround this site, which is typical of ble, open flowers were collected. Flowers and flower buds were stored farms in this region. in 70% ethanol until processing. Pollen was extracted by grinding the anthers into a container with ethanol, to later centrifuge the solution Experimental Setup for 5 min at 3,000 rpm. This pollen was processed by acetolysis (see During each year, a total of 16 locations were selected for Osmia shel- Pollen Processing) and used as a reference library for identifying pol- ters at the farm. Eight locations were positioned at the border of the len collected from bees and from their nests. farm, four at the east side and four at the west side, and the remain- ing eight locations were inside the farm. The inside locations were as Pollen Processing close as possible to the center of the field, and at least 200 m away To make the diagnostic characteristics of the pollen grains more vis- from the border of the field, given that the foraging range of O. lig- ible (Jones 2014), all pollen samples were processed by acetolysis. The naria is estimated to be 50–150 m (Dogterom 1999, Mader et al. complete pollen provisions from brood cells were acetolyzed. For this, 2010, Biddinger et al. 2013). Each nest location was a minimum of pollen was treated with an acetic anhydride acid and sulfuric acid 100 m away from other shelters. We selected locations as far as possi- solution (9:1 ratio) to dissolve tissues and remove lipids and debris, ble (>50 m) from commercial honey bee hives placed within the field. followed by washes of 70% ethanol and distilled water (Louveaux

Downloaded from https://academic.oup.com/aesa/advance-article-abstract/doi/10.1093/aesa/say028/5061887 by D H Hill Library - Acquis S user on 31 July 2018 Copyedited by: OUP

Annals of the Entomological Society of America, 2018, Vol. 00, No. 00

et al. 1978). Acetolyzed samples were homogenized with a vortex Table 1. Number of nest obtained per location (mean ± SE), and and two subsamples were mounted on microscope slides with fuchsin number of cells built per nest (mean ± SE), in shelters located stained gelatin. On each slide, we counted and identified all pollen inside or at the border of a large blueberry field grains to the lowest taxonomic level possible in 15 fields of view at Nests per location Cells per nest a magnification of 400×. On average there were 1,208 ± 25 (mean ± SE) grains in the counting area for brood cell samples, and 128 ± 13 Inside (no.) Border (no.) Center Border grains in scopal load samples. Pollen identification was done with the assistance of the reference pollen library from herbaceous and woody 2016 4.1 ± 0.8 (33) 4.5 ± 0.8 (36) 5.1 ± 0.7 4.9 ± 0.5 2017 3.0 ± 0.6 (21) 4.6 ± 0.9 (37) 4.0 ± 0.5 3.8 ± 0.2 plants collected at the field site. Of all pollen types found, 44% were identified to species, 28% to genus, 11% to family, and 17% was not possible to identify. Given the different taxonomic levels, from here we shelters at the border of the field. Five main pollen types were found will refer to them as pollen types. in these scopal loads (Fig. 1A), with significant differences in the

volume contribution of pollen types within locations (F(4,168) = 14.5, Data Analysis and Volumetric Correction P < 0.0001). Black cherry (Prunus serotina, Rosaceae) was the most To compare the number of nests and cells per nest obtained between abundant pollen type in the scopal loads of bees captured at both the inside and border locations, we used a t-test (P < 0.05). We per- locations. White clover (Trifolium repens, Fabaceae) and laurel wil- form the volumetric correction described by Da Silveira (1991) to low (Salix pentandra, Salicaceae) pollen were more abundant than determine the relative contribution of each pollen type to the total blueberry pollen, although these differences were not significant (all pollen volume by adjusting numerical counts for pollen size. In order P > 0.05). There was no significant effect of the shelter locations

to meet the normality and equal variance assumptions, an arcsine (F(1,168) = 0.00002, P = 0.99), and no significant interaction between

square-root transformation was applied to the data. A linear mixed factors (F(4,168) = 0.35, P = 0.84). (Fig. 1A). effects model was used to explore the effect of shelter location, pol- len types and the interaction effect (fix effects) on the contribution of Brood Cell Pollen each pollen type. Shelter was included as a random effect, with indi- In 2016 there were 23 nests included in the analysis, nine nests (with vidual tubes nested in each shelter. A post-hoc Tukey’s test (P < 0.05) 83 cells total) within five shelters inside the field, and 14 nests (with was used to compare the contribution of pollen types in each loca- 105 cells total) within five shelters at the border of the field. Twelve tion. To explore the effect of the order of cell construction on the pollen types were identified from O. lignaria provision masses in proportion of blueberry pollen in mass provisions, the positions of 2016. Black cherry (P. serotina), white clover (T. repens), laurel wil- cells in the nest was included as a fixed effect and the shelter as a ran- low (S. pentandra) and blueberry were the most common pollen dom effect. All data analyses were conducted in R version 3.4.3 (R sources. Pollen types with a volume contribution of less than 4% Development Core Team, Vienna, Austria) using the package ‘nlme’ included Rubus allegheniensis (Rocaceae), Rubus sp., Silene alba (Pinheiro et al. 2018) and ‘multcomp’ (Hothorn et al. 2008). (Caryophyllaceae), Oxalis stricta (Oxalidaceae) and three unidenti- fied pollen types. The locations of the nest did not have a significant

effect on the contribution of any of the pollen types (F(1,15) = 0.27, Results P = 0.61), but within locations we found differences in the contribu- tion of pollen types (F = 230.4, P < 0.001) (Fig. 1B). Together, Plant Richness (8,1432) We found fifty different blooming plant species during the 2016 sam- black cherry and white clover accounted for 82% of the pollen vol- pling. At the border of the field we found 47 species, with 6.0 ± 0.3 ume in the provision inside the field, and 74% at locations at the species per location (average ± SE), while we found 37 species within border of the field (Fig. 1B). The contribution of blueberry pollen the field, with 4.6 ± 0.3 species per location. In 2017 we found 31 was significantly lower than these two plants in locations at the bor- species, all of them previously observed in 2016. At the border of der of the field, and lower than black cherry at locations inside the the field we recorded 28 species, with 5.0 ± 0.2 species per location; field (all P < 0.05) (Fig. 1B). Overall, 89.5% of cells contained blue- inside the field we found 23 species, with 4.3 ± 0.2 species per loca- berry pollen, but only in 7.2% of the cells was the volume contribu- tion. Across both years, 68% of the species were common between tion of blueberry pollen >50%, and it was >90% in only 1.1% of the the border and inside of the farm (Supp. Table S1). cells. Volume contribution of blueberry pollen was consistently low as the percentage of blueberry pollen did not change among cells of the same nest regardless of the position, and therefore the timing of Nesting Success their construction (F(12,162) = 1.12, P = 0.34). During the 2016 season, O. lignaria nested in five out of the eight In 2017, there were 57 nests included in the pollen analysis, 21 shelters at the border of the field and five out of the eight shelters nests (with 49 cells total) from seven of the shelters inside the field, inside the field. In 2017, bees nested in all shelters at the border and and 35 nests (with 99 cells total) from all the shelters at the bor- in seven of the shelters inside the field. There were no differences der of the field. Twelve pollen types were recorded in mass provi- between the number of nests built between locations either in 2016 sions from brood cells, where white clover (T. repens), red clover (t = −0.3, df = 14, P = 0.75) or 2017 (t = −1.8, df = 13, P = 0.09) (T. pratense, Fabaceae), blueberry and Salix sp. (Salicaseae) were the (Table 1). Moreover, the average number of cells per nest was not sig- most common pollen types. Other pollen types with a volume con- nificantly different between locations in either year (2016: t = 0.85, tribution of less than 2% included Quercus sp. (Fagaceae), Prunus df = 14, P = 0.40; 2017: t = 0.57, df = 13, P = 0.58) (Table 1). sp. (Rosaceae), Onagraceae sp. 1, Onagraceae sp. 2, Phlox sp. (Polemoniaceae), and three unidentified pollen types. There was no

Scopal Loads significant effect of the locations of the nests (F(1,48) = 0.01, P = 0.92), In 2016, a total of 17 females were captured with pollen loads at but there was a significant difference among the pollen types within

seven shelters inside the field, and 20 females were captured at all locations (F(11,1606) = 81.9, P = 0.001) and a significant interaction

Downloaded from https://academic.oup.com/aesa/advance-article-abstract/doi/10.1093/aesa/say028/5061887 by D H Hill Library - Acquis S user on 31 July 2018 Copyedited by: OUP

Annals of the Entomological Society of America, 2018, Vol. 00, No. 00

2016, the percentage of blueberry pollen did not change among cells of the same nest regardless of the position, and therefore the timing

of their construction (F(9,131) = 1.14, P = 0.34).

Discussion Various Osmia species have been evaluated as alternative managed pollinators of numerous crops (Torchio 1984, Dogterom 1999, Matsumoto et al. 2009), and positive results have been observed for several species, particularly for the pollination of rosaceous tree crops (Bosch and Kemp 2001, 2002; Mader et al. 2010). However, there have been conflicting reports about whether they could be used as managed pollinators for blueberries, due to positive results in cage experiments (Dogterom 1999, Sampson and Cane 2000, Sampson et al. 2004, West and McCutcheon 2009), but their foraging behav- ior indicate that they would prefer to visit other plants in the field (Bosch and Kemp 2001, Sampson et al. 2009). Here, we report on the contribution of blueberry pollen to the scopal load and brood cells of O. lignaria nesting inside and at the border of a commercial blueberry field during crop bloom. Analysis of individual scopal loads allow us to determine whether or not bees are visiting several plant species during one foraging trip, while the mass provisions in brood cells show what bees are col- lecting over a longer time period. The low proportion of blueberry pollen in O. lignaria scopal loads indicate that, even if O. lignaria visit blueberry flowers to collect nectar, the use of blueberry pollen is limited. In contrast, when bumblebees (Bombus spp.) visit blue- berry flowers, the corbicular (pollen basket) loads have between 50 and 90% blueberry pollen (Moisan-Deserres et al. 2014). We can- not infer information about O. lignaria visitation rate to blueberry flowers, but nectar-harvesting visits usually result in low pollination levels for blueberries (Javorek et al. 2002). The small contribution of blueberry pollen to brood cells in both nesting locations (inside and at the border of the field) suggest that the contribution to blueberry pollination is limited. This lack of use of blueberry as a pollen source suggests that O. lignaria possess strong floral preferences in both natural and agri- cultural habitats, usually preferring rosaceous plants (Torchio 1982, Williams and Tepedino 2003, Sampson et al. 2009, Radmacher and Strohm 2010). In this case we found that the pollen that contributed the most to cell provisions belonged to back cherry (Rosaceae) and white and red clover (Fabaceae), plants common in the research area and in families that have been reported to be highly attractive to Osmia (Torchio 1982, Rust 1990, Kraemer et al. 2014). Pollen types with low contribution to the mass provision are probably collected indirectly when bees visit those flowers to collect nectar. These results Fig. 1. Volume contribution (±SE) of pollen in O. lignaria (A) scopal loads, (B) support previous findings that in field conditions, O. lignaria visit brood cells in 2016, and (C) brood cells in 2017, nesting inside (center) or at flowers other than those of blueberry (Sampson and Cane 2000). the edge (border) of a blueberry field in west Michigan. Means with the same letters at each location are not significantly different,P > 0.05. * indicated The presence of honey bees in high densities is a factor that can that the mean is 0. negatively affect visitation rate of other bees or change their foraging behavior (Thomson 2006, Walther-Hellwig et al. 2006, Lindström

between factors (F(11,1606) = 2.46, P = 0.009). This significant inter- et al. 2016), in some cases due to niche partitioning (Steffan- action was because Salix sp. showed a 11.8% higher contribution Dewenter and Tscharntke 2000), direct inference (Mallinger et al. to mass provision in shelters inside the field compared to shelters 2017) or nectar and pollen depletion (Carneiro and Martins 2012).

outside the field (F(1,48) = 12.94, P = 0.009) (Fig. 1C). In both loca- In our study, honey bee hives were placed at the field, so it is pos- tions the most abundant pollen belonged to white clover (T. repens), sible that the high density of honey bees on blueberry flowers could accounting for 39.7 ± 5.5% and 40.6 ± 4.0% (±SE) at the inside and have deterred O. lignaria from visiting them, which have also been at the border of the field, respectively. The percentage of blueberry observed for Osmia bicornis (L) (Hymenoptera: Megachilidae) in pollen was significantly lower than white clover at both locations (all blueberries (Hudewenz and Klein 2015). However, honey bees also P < 0.05) (Fig. 1C). Overall, only 44.6% of cells contained blueberry visit chery and clover flowers. Application of pesticides is another pollen, in 25.0% of the cells the volume contribution of blueberry factor that could have reduced O. lignaria visitation to blueber- was > 50%, and in 16.2% of the cells it was higher than >90%. As in ries. At this farm, the applications of insecticides during bloom is

Downloaded from https://academic.oup.com/aesa/advance-article-abstract/doi/10.1093/aesa/say028/5061887 by D H Hill Library - Acquis S user on 31 July 2018 Copyedited by: OUP

Annals of the Entomological Society of America, 2018, Vol. 00, No. 00

restricted, but not the applications of fungicides. Several authors determine the foraging patterns of Osmia cornifrons and resulting fruit set report sub-lethal effects of fungicides on O. lignaria (Ladurner et al. in a cherry orchard. Apidologie. 44: 738–749. 2005, Artz and Pitts-Singer 2015), so it is possible that they could Bosch, J., and W. P. Kemp. 1999. Exceptional cherry production in an orchard have a repellent effect, making blueberry flowers less attractive to pollinated with blue orchard bees. Bee World. 80: 163–173. Bosch, J., and W. P. Kemp. 2001. How to manage the blue orchard bee. O. lignaria. However, these sprays would also have contacted the Sustainable Agriculture Network (SAN), Beltsville, MD. clover in the field yet this was heavily collected by the bees. Bosch, J., J. Bosch, and W. P. Kemp. 2002. Developing and establishing bee Many Osmia species tend to collect resources that are close to species as crop pollinators: the example of Osmia spp. (Hymenoptera: their nests, especially when they have their preferred resources in Megachilidae) and fruit trees. Bull. Entomol. Res. 92: 3–16. the vicinity of the nest (Williams and Tepedino 2003, Monzón et al. Bosch, J., W. P. Kemp, and G. E. Trostle. 2006. Bee population returns and 2004, Biddinger et al. 2013), but O. lignaria can fly up to 600 m (Rust cherry yields in an orchard pollinated with Osmia lignaria (Hymenoptera: 1990). Thus, it is not surprising to find pollen from plants that were Megachilidae). J. Econ. Entomol. 99: 408–413. found only outside of the field in the nests that were located inside the Cane, J. H. 1997. Lifetime monetary value of individual pollinator: the bee farm. The bee’s floral preferences and flight range make it difficult to Habropoda laboriosa at rabbiteye blueberry (Vaccinium ashei Reade). restrict them from visiting other plants that bloom at the same time Acta Hort. 446: 67–70. Cane, J. H., T. Griswold, and F. D. Parker. 2007. Substrates and materials used as the target crop, and so low fidelity to blueberry is likely to result in for nesting by North American Osmia bees (Hymenoptera: Apiformes: high abundance of other pollen sources in mass provisions. Megachilidae). Ann. Entomol. Soc. Am. 100: 350–358. Osmia pollination efficiency and visitation rate on blueberries Carneiro, L. T., and Martins, C. F. 2012. Africanized honey bees pollinate can be variety-dependent due to several flower morphological char- and preempt the pollen of Spondias mombin (Anacardiaceae) flowers. acteristics, including corolla width and pistil length (Sampson and Apidologie. 43: 474–486. Cane 2000, Courcelles et al. 2013, Sampson et al. 2013). It is possi- Courcelles, D. M. M., L. Button, and E. Elle. 2013. Bee visit rates vary with ble that the few nest provisions with high content of blueberry pollen floral morphology among highbush blueberry cultivars (Vaccinium corym- (>90%) were made during the blooming period of a specific variety bosum L.). J. Appl. Entomol. 137: 693–701. that could make the access to pollen easier. It would be important to Da Silveira, F. A. 1991. Influence of pollen grain volume on the estimation of test how the pollen preferences of O. lignaria changes when they are the relative importance of its source to bees. Apidologie. 22: 495–502. Dedej, S., and K. S. Delaplane. 2003. Honey bee (Hymenoptera: Apidae) pol- in fields with multiple or single varieties. lination of rabbiteye blueberry Vaccinium ashei var. “Climax” is pollinator In this study we found that O. lignaria collects blueberry pollen density-dependent. J. Econ. Entomol. 96: 1215–1220. in field conditions, but its contribution to scopal loads and provision Dogterom, M. H. 1999. Pollination by four species of bees on highbush blue- masses is low in comparison with other pollen types. Additionally, berry. PhD dissertation. Simon Fraser University, Burnaby, Canada. the use of blueberry pollen does not change during the nesting period Gallai, N., J.-M. Salles, J. Settele, and B. E. Vaissière. 2009. Economic valua- nor depending on the location of the shelter (inside the field or at tion of the vulnerability of world agriculture confronted with pollinator the border of the field). These results highlight that O. lignaria may decline. Ecol. Econ. 68: 810–821. not be well-suited for commercial pollination of highbush blueberry Garibaldi, L. A., M. A. Aizen, A. M. Klein, S. A. Cunningham, and L. D. Harder. in open field settings in this region, and suggests that other man- 2011. Global growth and stability of agricultural yield decrease with pol- aged bees (e.g., bumble bees) or wild bees (e.g., Habropoda labo- linator dependence. Proc. Natl. Acad. Sci. U. S. A. 108: 5909–5914. Garibaldi, L. A., I. Steffan-Dewenter, R. Winfree, M. A. Aizen, R. Bommarco, riosa (Fabricius) (Hymenoptera: Apidae)) that are more efficient at S. A. Cunningham, C. Kremen, L. G. Carvalheiro, L. D. Harder, O. Afik, pollinating blueberries and have higher fidelity for its flowers (Cane et al. 2013. Wild pollinators enhance fruit set of crops regardless of honey 1997, Javorek et al. 2002) could be a better alternative to honey bees bee abundance. Science. 339: 1608–1611. for pollination of blueberries. Hothorn, T., F. Bretz, and P. Westfall. 2008. Simultaneous inference in general parametric models. Biom. J. 50: 346–363. Hudewenz, A., and A. M. Klein. 2015. Red mason bees cannot compete Supplementary Data with honey bees for floral resources in a cage experiment. Ecol. Evol. 5: Supplementary data are available at Annals of the Entomological 5049–5056. Society of America online. Javorek, S. K., K. E. Mackenzie, and S. P. Vander Kloet. 2002. Comparative pollination effectiveness among bees (Hymenoptera: Apoidea) on lowbush blueberry (Ericaceae: Vaccinium angustifolium). Ann. Entomol. Soc. Am. Acknowledgments 95: 345–351. Jones, G. D. 2014. Pollen analyses for pollination research, acetolysis. J. We thank Margaret Hartman, Nora Straquadine, Olivia Horton, and Michael Pollinat. Ecol. 13: 203–217. Killewald for their help with field data collection and samples processing. We Klein, A. M., B. E. Vaissière, J. H. Cane, I. Steffan-Dewenter, S. A. Cunningham, also thank Dan Stafford of Cornerstone Ag LLC for access to the farm. This C. Kremen, and T. Tscharntke. 2007. Importance of pollinators in chang- research was improved by the advice of Larry Gut and Matthew Grieshop. ing landscapes for world crops. Proc. Biol. Sci. 274: 303–313. We thank the anonymous reviewers for their comments on the manuscript. Kraemer, M. E., F. D. Favi, and C. E. Niedziela. 2014. Nesting and pollen We acknowledge financial support provided by aFulbright Association to the preference of Osmia lignaria lignaria (Hymenoptera: Megachilidae) in lead author, the National Institute of Food and Agriculture, U.S. Department Virginia and North Carolina orchards. Environ. Entomol. 43: 932–941. of Agriculture (Award 2012-51181-20105) from the Specialty Crops Research Ladurner, E., J. Bosch, W. P. Kemp, and S. Maini. 2005. Assessing delayed and Initiative, and the Department of Entomology of Michigan State University. acute toxicity of five formulated fungicides to Osmia lignaria Say and Apis mellifera. Apidologie. 36: 449–460. References Cited Levin, M. D. 1966. Biological notes on Osmia lignaria and Osmia californica (Hymenoptera: Apoidea, Megachilidae). J. Kansas Entomol. Soc. 39: 524–535. Artz, D. R., and T. L. Pitts-Singer. 2015. Effects of fungicide and adjuvant Lindström, S. A. M., L. Herbertsson, M. Rundlöf, R. Bommarco, and H. sprays on nesting behavior in two managed solitary bees, Osmia lignaria G. Smith. 2016. Experimental evidence that honeybees depress wild insect and Megachile rotundata. PLoS One. 10: e0135688. densities in a flowering crop. Proc. R. Soc. B Biol. Sci. 283: 20161641. Biddinger, D. J., N. K. Joshi, E. G. Rajotte, N. O. Halbrendt, C. Pulig, K. Louveaux, J., A. Maurizio, and G. Vorwohl. 1978. Methods of melissopalynol- J. Naithani, and M. Vaughan. 2013. An immunomarking method to ogy. Bee World. 51: 139–153.

Downloaded from https://academic.oup.com/aesa/advance-article-abstract/doi/10.1093/aesa/say028/5061887 by D H Hill Library - Acquis S user on 31 July 2018 Copyedited by: OUP

Annals of the Entomological Society of America, 2018, Vol. 00, No. 00

Mackenzie, K. E. 1997. Pollination requirements of three highbush blue- Sampson, B. J., S. J. Stringer, J. H. Cane, and J. M. Spiers. 2004. Screenhouse berry (Vaccinium corymbosum L.) cultivars. J. Amer Soc. Hort. Sci. 122: evaluations of a mason bee Osmia ribifloris (Hymenoptera: Megachilidae) 891–896. as a pollinator for blueberries in the southeastern United States. Small Mader, E., M. Spivak, and E. Evans. 2010. Managing alternative pollinators. Fruits Rev. 3: 381–392. NRAES, Ithaca, NY. Sampson, B. J., J. H. Cane, G. T. Kirker, S. J. Stringer, and J. M. Spiers. Mallinger, R. E., H. R. Gaines-Day, and C. Gratton. 2017. Do managed bees 2009. Biology and management potential for three orchard bee species have negative effects on wild bees?: a systematic review of the literature. (Hymenoptera: Megachilidae): Osmia ribifloris Cockerell, O. lignaria PLoS One. 12: e0189268. (Say) and O. chalybea Smith with emphasis on the former, pp. 549–555. Matsumoto, S., A. Abe, and T. Maejima. 2009. Foraging behavior of Osmia In Proceedings, IXth IS on Vaccinium, 13–16 July 2008, Corvallis, OR. cornifrons in an apple orchard. Sci. Hortic. 121: 73–79. Sampson, B. J., S. J. Stringer, and D. A. Marshall. 2013. Blueberry floral attrib- McGregor, S. E. 1976. Insect pollination of cultivated crop plants. Agricultural utes and their effect on the pollination efficiency of an oligolectic bee, Reseach Service, Washington, DC. Osmia ribifloris Cockerell (Megachilidae: Apoidea). HortScience. 48: Medler, J. T. 1967. Biology of Osmia in trap nests in Wisconsin (Hymenoptera: 136–142. Megachilidae). Ann. Entomol. Soc. Am. 60: 338–344. Sheffield, C. S. 2014. Pollination, seed set and fruit quality in apple: studies Moisan-Deserres, J., M. Girard, M. Chagnon, and V. Fournier. 2014. Pollen with Osmia lignaria (Hymenoptera: Megachilidae) in the Annapolis val- loads and specificity of native pollinators of lowbush blueberry. J. Econ. ley, Nova Scotia, Canada. J Pollinat Ecol. 12: 120–128. Entomol. 107: 1156–1162. Sheffield, C. S., S. M. Westby, R. F. Smith, and P. G. Kevan. 2008. Potential of Monzón, V., J. Bosch, and J. Retana. 2004. Foraging behavior and pollinat- bigleaf lupine for building and sustaining Osmia lignaria populations for ing effectiveness of Osmia cornuta (Hymenoptera: Megachilidae) and pollination of apple. Can. Entomol. 140: 589–599. Apis mellifera (Hymenoptera: Apidae) on “Comice” pear. Apidologie. 35: Steffan-Dewenter, I., and T. Tscharntke. 2000. Resource overlap and pos- 575–585. sible competition between honey bees and wild bees in central Europe. Newcomb, L. 1977. Wildflower guide. Little Brown and Company, New York, NY. Oecologia. 122: 288–296. Nogué, S., P. R. Long, A. E. Eycott, L. de Nascimento, J. M. Fernández- Stubbs, C. S., Drummond, F. A., and Osgood, E. A. 1994. Osmia ribifloris Palacios, G. Petrokofsky, V. Vandvik, and K. J. Willis. 2016. Pollination biedermannii and Megachile rotundata (Hymenoptera: Megachilidae) service delivery for European crops: challenges and opportunities. Ecol. Introduced into the lowbush blueberry agroecosystem in Maine. J. Kansas Econ. 128: 1–7. Entomol. Soc. 67: 173–185. Peterson, R. T., and M. McKenny. 1996. A Peterson field guide to wildflowers: Thomson, D. 2006. Detecting the effects of introduced species: a case study of Northeastern and North-central North America. Houghton Mifflin, New competition between Apis and Bombus. OIKOS. 114: 407–418. York, NY. Torchio, P. F. 1982. Field experiments with the pollinator species, Osmia lig- Petrides, G. A. 1972. Trees and shrubs, 2th ed. Houghton Mifflin, New York, naria propinqua Cresson, in apple orchards: I, 1975 Studies (Hymenoptera: NY. Megachilidae). J. Kansas Entomol. Soc. 55: 136–144. Phillips, J. K., and Klostermeyer, E. C. 1978. Nesting behavior of Osmia Torchio, P. F. 1984. Field experiments with the pollinator species, Osmia lignaria propinqua Cresson (Hymenoptera: Megachilidae). J. Kansas lignaria propinqua Cresson (Hymenoptera: Megachilidae) in apple Entomol. Soc. 51: 91–108. Orchards: III, 1977 studies. J. Kansas Entomol. Soc. 57: 517–521. Pinheiro, J., D. Bates, S. DebRoy, and D. Sarkar. 2018. nlme: linear and nonlin- Torchio, P. F. 1989. In-nest biologies and development of immature stages of ear mixed effects models. R package. https://cran.r-project.org/web/pack- three Osmia species (Hymenoptera: Megachilidae). Ann. Entomol. Soc. ages/nlme/citation.html Am. 82: 599–615. Potts, S. G., J. C. Biesmeijer, C. Kremen, P. Neumann, O. Schweiger, and W. Torchio, P. F. 1990. Osmia ribifloris, a native bee species developed as a E. Kunin. 2010. Global pollinator declines: trends, impacts and drivers. commercially managed pollinator of highbush blueberry (Hymenoptera: Trends Ecol. Evol. 25: 345–353. Megachilidae). J. Kansas Entomol. Soc. 63: 427–436. Radmacher, S., and E. Strohm. 2010. Factors affecting offspring body size in VanEngelsdorp, D., J. Hayes, Jr, R. M. Underwood, and J. Pettis. 2008. A sur- the solitary bee Osmia bicornis (Hymenoptera, Megachilidae). Apidologie. vey of honey bee colony losses in the U.S., fall 2007 to spring 2008. PLoS 41: 169–177. One. 3: e4071. Ratti, C. M., Higo, H. A., Griswold, T., and Winston, M. L. 2008. Bumble bees Vanengelsdorp, D., and M. D. Meixner. 2010. A historical review of managed influence berry size in commercial Vaccinium spp. cultivation in British honey bee populations in Europe and the United States and the factors Columbia. Can. Entomol. 140: 348–363. that may affect them. J. Invertebr. Pathol. 103 (Suppl 1): S80–S95. Ritzinger, R., and P. M. Lyrene. 1999. Flower morphology in blueberry species Walther-Hellwig, K., G. Fokul, R. Frankl, R. Büchler, K. Ekschmitt, and and hybrids. Hort Science. 34: 130–131. V. Wolters. 2006. Increased density of honeybee colonies affects foraging Rust, R. 1990. Spatial and temporal heterogeneity of pollen foraging in Osmia bumblebees. Apidologie. 37: 517–532. lignaria propinqua (Hymenoptera: Megachilidae). Environ. Entomol. 9: West, T., and T. McCutcheon. 2009. Evaluating Osmia cornifrons as pollina- 332–338. tors of highbush blueberry. Int. J. Fruit Sci. 9: 115–125. Sampson, B. J., and J. H. Cane. 2000. Pollination efficiencies of three bee Williams, N. M., and V. J. Tepedino. 2003. Consistent mixing of near and dis- (Hymenoptera: Apoidea) species visiting rabbiteye blueberry. J. Econ. tant resources in foraging bouts by the solitary mason bee Osmia lignaria. Entomol. 93: 1726–1731. Behav. Ecol. 14: 141–149.

Downloaded from https://academic.oup.com/aesa/advance-article-abstract/doi/10.1093/aesa/say028/5061887 by D H Hill Library - Acquis S user on 31 July 2018View publication stats