We thank Colby Carpenter and Spencer Mathias for their assistance in 3D printing design. We thank Ellen Klinger for assistance in producing the photographic figures and Jonathan B. Koch for providing assistance with revisions. Funding was provided by the USDA-ARS-Pollinating Insect Biology, Management, and Systematics Research Unit.

1. Print pollen trap structures
<ol>
	<li>Download the appropriate STL file for the nest box that bumble bees are nesting in (e.g., Biobest or Koppert style hives, https://www.ars.usda.gov/pacific-west-area/logan-ut/pollinating-insect-biology-management-systematics-research/docs/pollen-traps/). The files are available to the public, free for download and modification by the end user.</li>
	<li>Open the STL file in the printer program. Follow printer manufacturer directions to build the four trap components. 
	NOTE...

<ol>
	<li>Michener, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The bees of the world. , (2000).</li><li>Corbet, S. A., Williams, I. H., Osborne, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bees+and+the+pollination+of+crops+and+wild+flowers+in+the+European+Community.">Bees and the pollination of crops and wild flowers in the European Community.</a> Bee world. 72 (2), 47-59 (1991).</li><li>Cameron, S. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterns+of+widespread+decline+in+North+American+bumble+bees.">Patterns of widespread decline in North American bumble bees.</a> Proceedings of the National Academy of Sciences. 108 (2), 662-667 (2011).</li><li>Goulson, D., Nicholls, E., Bot&#237;as, C., Rotheray, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bee+declines+driven+by+combined+stress+from+parasites,+pesticides,+and+lack+of+flowers.">Bee declines driven by combined stress from parasites, pesticides, and lack of flowers.</a> Science. 347 (6229), 1255957 (2015).</li><li>Jha, S., Stefanovich, L. E. V., Kremen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bumble+bee+pollen+use+and+preference+across+spatial+scales+in+human-altered+landscapes.">Bumble bee pollen use and preference across spatial scales in human-altered landscapes.</a> Ecological Entomology. 38 (6), 570-579 (2013).</li><li>Thomson, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Competitive+interactions+between+the+invasive+European+honey+bee+and+native+bumble+bees.">Competitive interactions between the invasive European honey bee and native bumble bees.</a> Ecology. 85 (2), 458-470 (2004).</li><li>Kleijn, D., Raemakers, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+retrospective+analysis+of+pollen+host+plant+use+by+stable+and+declining+bumble+bee+species.">A retrospective analysis of pollen host plant use by stable and declining bumble bee species.</a> Ecology. 89 (7), 1811-1823 (2008).</li><li>Harmon-Threatt, N. H., Kremen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bumble+bees+selectively+use+native+and+exotic+species+to+maintain+nutritional+intake+across+highly+variable+and+invaded+floral+resource+pools.">Bumble bees selectively use native and exotic species to maintain nutritional intake across highly variable and invaded floral resource pools.</a> Ecological Entomology. 40, 471-478 (2015).</li><li>Harmon-Threatt, N. H., Valpine, P., Kremen, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+resource+preferences+of+a+native+bumblebee:+the+effects+of+availability+and+use-availability+models+on+preference+estimates.">Estimating resource preferences of a native bumblebee: the effects of availability and use-availability models on preference estimates.</a> Oikos. , (2016).</li><li>Martin, A. P., Carreck, N. M. L., Swain, J. L., Goulson, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modular+system+for+trapping+and+mass-marking+bumblebees:+applications+for+studying+food+choice+and+foraging+range.">A modular system for trapping and mass-marking bumblebees: applications for studying food choice and foraging range.</a> Apidologie. 37, (2006).</li><li>Saifuddin, M., Jha, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Colony-level+variation+in+pollen+collection+and+foraging+preferences+among+wild-caught+bumble+bees.+(Hymenoptera:+Apidae).">Colony-level variation in pollen collection and foraging preferences among wild-caught bumble bees. (Hymenoptera: Apidae).</a> Environmental Entomology. 42 (2), 393-401 (2014).</li><li>Heinrich, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Bumblebee Economics. , (2004).</li><li>Leonhart, S. D., Bluthgen, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+same,+but+different:+pollen+foraging+in+honeybee+and+bumblebee+colonies.">The same, but different: pollen foraging in honeybee and bumblebee colonies.</a> Apidologie. 43, (2012).</li><li>Kriesell, L., Hilpert, A., Leonhardt, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Different+but+the+same:+bumblebee+species+collect+pollen+of+different+plant+sources+but+similar+amino+acid+profiles.">Different but the same: bumblebee species collect pollen of different plant sources but similar amino acid profiles.</a> Apidologie. 48, 102-116 (2017).</li><li>Al-Tikrity, W. S., Benton, A. W., Hillman, R. C., Clarke, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+relationship+between+the+amount+of+unsealed+brood+in+honeybee+colonies+and+their+pollen+collection.">The relationship between the amount of unsealed brood in honeybee colonies and their pollen collection.</a> Journal of Apicultural Research. 11 (1), 9-12 (1972).</li><li>Spaethe, J., Weidenm&#252;ller, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Size+variation+and+foraging+rate+in+bumblebees+(Bombus+terrestris).">Size variation and foraging rate in bumblebees (Bombus terrestris).</a> Insectes Sociaux. 49 (2), 142-146 (2002).</li><li>Goodwin, R. M., Perry, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+pollen+traps+to+investigate+the+foraging+behaviour+of+honey+bee+colonies+in+kiwifruit.">Use of pollen traps to investigate the foraging behaviour of honey bee colonies in kiwifruit.</a> New Zealand Journal of Crop and Horticulture Science. 20 (1), 23-26 (1992).</li><li>Chua, C. K., Leong, K. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> 3D PRINTING AND ADDITIVE MANUFACTURING: Principles and Applications (with Companion Media Pack) of Rapid Prototyping. , (2014).</li><li>Kearns, C. A., Inouye, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Techniques for Pollination Biologists. , (1993).</li><li>Velthuis, H. H., van Doorn, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+century+of+advances+in+bumblebee+domestication+and+the+economic+and+environmental+aspects+of+its+commercialization+for+pollination.">A century of advances in bumblebee domestication and the economic and environmental aspects of its commercialization for pollination.</a> Apidologie. 37 (4), 421-451 (2006).</li><li>Moisan-Deserres, J., Girard, M., Chagnon, M., Fournier, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pollen+loads+and+specificity+of+native+pollinators+of+lowbush+blueberry.">Pollen loads and specificity of native pollinators of lowbush blueberry.</a> Journal of Economic Entomology. 107 (3), 1156-1162 (2014).</li><li>Medler, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+nest+of+Bombus+huntii+Greene+(Hymenoptera:+Apidae).">A nest of Bombus huntii Greene (Hymenoptera: Apidae).</a> Entomological News. 70, 179-182 (1959).</li><li>Husband, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observation+on+colony+of+bumblebee+species+(Bombus+spp).">Observation on colony of bumblebee species (Bombus spp).</a> Great Lakes Entomologist. 10, 83-85 (1977).</li><li>Buttermore, R. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observations+of+successful+Bombus+terrestris++(L),+(Hymenoptera:+Apidae)+colonies+in+Southern+Tasmania.">Observations of successful Bombus terrestris (L), (Hymenoptera: Apidae) colonies in Southern Tasmania.</a> Australian Journal of Entomology. 36, 251-254 (1997).</li><li>Goulson, D., Peat, J., Stout, J. C., Tucker, J., Darvill, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Can+alloethism+in+workers+of+the+bumblebee,+Bombus+terrestris,+be+explained+in+terms+of+foraging+efficiency.">Can alloethism in workers of the bumblebee, Bombus terrestris, be explained in terms of foraging efficiency.</a> Animal Behaviour. 64 (1), 123-130 (2002).</li><li>Couvillon, M. J., Jandt, J. M., Duong, N. H. I., Dornhaus, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ontogeny+of+worker+body+size+distribution+in+bumble+bee+(Bombus+impatiens)+colonies.">Ontogeny of worker body size distribution in bumble bee (Bombus impatiens) colonies.</a> Ecological Entomology. 35 (4), 424-435 (2010).</li><li>Russell, A. L., Morrison, S. J., Moschonas, E. H., Papaj, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patterns+of+pollen+and+nectar+foraging+specialization+by+bumblebees+over+multiple+timescales+using+RFID.">Patterns of pollen and nectar foraging specialization by bumblebees over multiple timescales using RFID.</a> Scientific Reports. 7 (1), 1-13 (2017).</li><li>Hagbery, J., Nieh, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Individual+lifetime+pollen+and+nectar+foraging+preferences+in+bumble+bees.">Individual lifetime pollen and nectar foraging preferences in bumble bees.</a> Naturwissenschaften. 99 (10), 821-832 (2012).</li><li>Baur, A., Strange, J. P., Koch, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Foraging+economics+of+the+Hunt+bumble+bee,+a+viable+pollinator+for+commercial+agriculture.">Foraging economics of the Hunt bumble bee, a viable pollinator for commercial agriculture.</a> Environmental Entomology. 48 (4), 799-806 (2019).</li><li>Winter, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Importation+of+non-native+bumble+bees+into+North+America:+potential+consequences+of+using+Bombus+terrestris+and+other+non-native+bumble+bees+for+greenhouse+crop+pollination+in+Canada,+Mexico,+and+the+United+States.">Importation of non-native bumble bees into North America: potential consequences of using Bombus terrestris and other non-native bumble bees for greenhouse crop pollination in Canada, Mexico, and the United States.</a> San Francisco. 33, (2006).</li><li>Ruz, L., Herrera, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Preliminary+observations+on+foraging+activities+of+Bombus+dahlbomii+and+Bombus+terrestris+(Hym:+Apidae)+on+native+and+non-native+vegetation+in+Chile.">Preliminary observations on foraging activities of Bombus dahlbomii and Bombus terrestris (Hym: Apidae) on native and non-native vegetation in Chile.</a> Acta Horticulturae. 561, 165-169 (2001).</li></ol>

The authors have nothing to disclose.

Collection of pollen from bumble bee colony entrances can allow for a variety of ecological and agricultural studies. Identifying the floral sources from which bumble bees collect pollen provides valuable information and insight into the diversity of plants that contribute to a colony&#8217;s overall diet19. Identifying the pollen source has implications for both agricultural production and studies of ecosystem services in wild lands12,20....

Bumble bees (Bombus spp.) are large robust insects that are found across the temperate, alpine, and arctic regions of the world1. They are important to&#160;plant communities&#160;and provide important pollination service for the agricultural crops that they visit2. Recent declines in the&#160;abundance and distribution of several species has brought their importance as pollinators to the forefront of&#160;public&#160;awareness3. Researchers have identified several stressors that are likely contributing to population&#160;declines including a lack of diverse and abundant floral resources on which bumble bees forage4. Identifying which&#160;plant species bumble bees forage from allows researchers and land managers to understand how bumble bees may be responding to changes in resource availability, competition, and&#160;anthropogenic disturbances5,6.
Studies investigating the pollen foraging preferences of bumble bees are often conducted by researchers catching individual bees foraging at flowers, and then removing the corbicular pollen loads from specimens for further processing and identification7,8,9,10. While this method provides insight into how a species or an assemblage of bumble bee species utilizes the resources in an area7, it is time intensive and potential differences in preferences among hives cannot be discerned without additional molecular analyses to identify colony of origin of the foraging bee11.
For some studies of foraging dynamics, it is desired to conduct the studies at individual colonies; however, wild bumble bee nests are generally located underground or at ground level making them difficult to locate12. Commercially produced bumble bee hives provide researchers greater access and better experimental control and the removal of pollen off workers is still primarily conducted by capturing foragers as they return to the hive and manually removing their corbicular pollen loads13,14. The removal of pollen by hand from the corbicula of a bee is time intensive with a low hourly yield of pollen especially at hive entrances where the rate of returning pollen foragers may be low. Additionally, manually removing pollen from bees can result in stings from disturbed workers.
Pollen traps have been used for experimental removal of pollen from honey bees for decades15; yet, a passive method for removing pollen from bumble bees has not been developed. The primary obstacle in developing a mechanism to remove pollen from returning forager bumble bees is the large variation of worker sizes that exist in a bumble bee colony16. Honey bee pollen traps are effective largely because honey bee worker size does not vary much. Additionally, these traps require only minor manipulations after installation and don&#8217;t require bees to be sacrificed17. This is achieved using screens or plastic surfaces that dislodge the pollen off of the hind legs of workers as they return to the hive. These traps remove only a portion of the pollen loads from returning foragers and the various designs of those result in varied efficiencies at pollen collection. As the pollen is removed from the bee legs, it falls through a screen and into a collection basin to which the bees have no access, so that the researcher can remove it with only minor disturbance to the hive.
The purpose of the present study is to adapt the techniques used for collecting pollen from honey bee hives and apply them to bumble bee nests using 3D printed structures and test the trap designs on colonies of Bombus huntii. The design process followed the assumptions that the traps should be inexpensive to produce, adaptable to a variety of bumble bee species, cause minimal harm or disturbance to the bees, and that the rate of pollen removal should exceed hand collection of pollen. Three-dimensional printing technology is versatile, easily accessible, and a cost-effective tool allowing researchers to replicate and modify objects for specific purposes18. The technique presented here instructs the user to build pollen traps and attach them onto commercially available bumble bee colonies. The traps are not designed to be use with wild colonies. These traps passively remove the corbicular pollen loads from the hind legs of pollen carrying bumble bees as they return to their nest boxes.

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	<colgroup>
		<col />
		<col span="2" />
		<col />
	</colgroup>
	<tbody>
		<tr height="35">
			<td height="35" style="height:35px;width:71px;">MakerBot Replicator+</td>
			<td style="width:87px;">MakerBot</td>
			<td style="width:87px;">Model PABH65</td>
			<td style="width:217px;"></td>
		</tr>
		<tr height="52">
			<td height="52" style="height:52px;width:71px;">MakerBot Tough Material</td>
			<td style="width:87px;">PLA Filament</td>
			<td style="width:87px;"></td>
			<td>various colors</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:71px;">Nest Box</td>
			<td style="width:87px;">Biobest</td>
			<td style="width:87px;"></td>
			<td>Not sold publicly without bee purchase</td>
		</tr>
	</tbody>
</table>

a 3d printed pollen trap for bumble bee (bombus) hive entrances

To verify the plant sources from which bumble bees forage for pollen, individuals must be collected to remove their corbicular pollen loads for analysis. This has traditionally been done by netting foragers at nest entrances or on flowers, chilling the bees on ice, and then removing the pollen loads from the corbiculae with forceps or a brush. This method is time and labor intensive, may alter normal foraging behavior, and can result in stinging incidents for the worker performing the task. Pollen traps, such as those used on honey bee hives, collect pollen by dislodging corbicular pollen loads from the legs of workers as they pass through screens at the nest entrance. Traps can remove a large quantity of pollen from returning forager bees with minimal labor, yet to date no such trap is available for use with bumble bee colonies. Workers within a bumble bee colony can vary in size making size selection of entrances difficult to adapt this mechanism to commercially reared bumble bee hives. Using 3D printing design programs, we created a pollen trap that successfully removes the corbicular pollen loads from the legs of returning bumble bee foragers. This method significantly reduces the amount of time required by researchers to collect pollen from bumble bee foragers returning to the colony. We present the design, results of pollen removal efficiency tests, and suggest areas of modifications for investigators to adapt traps to a variety of bumble bee species or nest box designs.

Eight different pollen filter designs were tested to determine their efficacy and efficiency at removing corbicular pollen loads from returning bumble bee workers. All designs were successful at removing at least of one corbicular pollen load from a returning forager. However, some were found to slow workers from leaving or entering the hive or failed to remove pollen loads (Table 1). Pollen traps with various filters were tested sequentially on 4 laboratory reared colonies of B. huntii Greene f...

Watch this Scientific Journal Video about A 3D Printed Pollen Trap for Bumble Bee Bombus Hive Entrances at JoVE.com

A 3D Printed Pollen Trap for Bumble Bee Bombus Hive Entrances

We present a non-lethal and automated mechanism to collect pollen from bumble bee (Bombus) workers returning to a hive. Instructions for producing, preparing, installing and using the devices are included. By using 3D-printed objects, modification to the design was timely, efficient and allowed for quick turnaround for testing.

A 3D Printed Pollen Trap for Bumble Bee (Bombus) Hive Entrances

To verify the plant sources from which bumble bees forage for pollen, individuals must be collected to remove their corbicular pollen loads for analysis.  ...

This method allows researchers to collect pollen from bumblebee colonies with minimal disturbance to the bees and low risk of bee stings to the researcher. Using this protocol, pollen can be collected from multiple colonies simultaneously, permitting researchers to use more colonies with less labor and expense than hand collecting pollen. This method will benefit research in pollination and bee health, pesticide science and environmental contamination and can be adapted to multiple species of bumblebees.Begin by removing the support structures printed with the trap body and catch basin, including those of the sieve structure and the trap body. Clear any plastic strands crossing the raised edges of the pollen filter with a hand drill, then use a box cutting razor blade and sandpaper to even out any bumps or raised edges on the flat side of the filter. Gently push the plastic pollen filter through one side of the trap body.The filter will only fit in one way as the left side of the trap has a larger opening to accommodate passage of the raised filter cones. If the side slits are too small for the pollen filter to slide through smoothly, use a razor to scrape enough plastic away from the slit in the trap body. Ensure that the filter fits securely in place with no more than a two millimeter gap between it and the trap body.Slide the raised edges on the bottom of the trap body into the groove on top of the catch basin. The catch basin should be positioned directly underneath the sieve region of the trap body. Cut or sand the plastic to allow smooth placement and removal of the catch basin.Placement of the catch basin will secure the pollen filter into place. Stop pollen feeding 24 to 48 hours before deploying colonies, which will cause workers to use up any stored pollen and stimulate them to leave the nest. Prepare the hive trap body for installation by placing a trap closure insert into the filter slot to prevent bees from escaping.Working under a red light, lift the plastic nest box out of the cardboard outer box and locate the entrance at the front of the nest. For corporate style hive entrances, pull up on the entrance tab until both entrance holes are open. Then insert the two tubes of the pollen trap into the entrance holes ensuring that the sieve of the pollen trap is on the bottom.Gently push down on the plastic entrance tab to secure the pollen trap in place. To install the pollen trap into bio best style hive entrances, use a flathead screwdriver to gently pry the plastic entrance device from the nest box. Insert the pollen trap into the nest entrance holes until it is placed firmly against the nest.Then secure it to the nest with tape or quick dry glue where the trap contacts the nest box. Lace the nest boxes into this study area, providing cover from precipitation and anchorage for wind as these can adversely affect the quality and quantity of the collected pollen. Provide the hives with adequate sun cover to prevent overheating.Remove the trap closure insert from the trap body to allow bees to forage freely so that they can orient themselves with the surrounding area and the location of their nest. Orientation flight time should be complete in 24 hours under normal conditions. To engage the trap, slide the pollen filter into the filter slot, ensuring that it is securely in place.Install the catch basin by sliding it onto the trap body from the front until it's fully closed. If the catch basin is loose or falls off the trap body, use a rubber band to secure it. Observe bees entering and exiting the pollen trap at first deployment to ensure the pollen filter holes are large enough.If workers are unable to pass through the pollen filter, remove the filter and use the hand drill to enlarge the holes. Increase the diameter sequentially as holes that are too large will not collect any pollen. Once bees are able to pass through the filter, continue observing the entrance to ensure pollen is being removed upon re-entry.After the designated period of pollen collection, remove the catch basin from the trap body and process the pollen loads according to the experimental design. Remove the pollen filter to allow workers to forage freely, leaving the trap body attached to the hive for the duration of the experiment. Eight pollen filter designs were tested to determine their efficacy and efficiency at removing corbicular pollen loads from returning bumblebee workers.All designs were successful at removing at least one load, but some were found to slow workers from leaving or entering the hive, or failed to remove pollen loads. The filters were tested sequentially on four laboratory reared colonies of bee green foraging on Phacelia tanacetifolia for a cumulative 138.5 hours and 229 collected corbicular pollen loads over seven days. 52 hours of video observation and 142 pollen loads were collected during the test period.The number of corbicular pollen loads collected was divided by the number of observed pollen laden foragers that passed through a filter to calculate efficiency. Pollen filter design efficiencies ranged from two to 58.9%Corbicular loads were removed from the legs and fell as cohesive pellets of pollen into the catch basin. Circular filter openings improved pollen collection and movement of workers into the nest environment.In addition, filter designs that had raised structures that extended away from the nest box also improved pollen removal from the hind legs of foragers. Design number eight, a circular trap entrance with raised edges was the final design. When fixing the pollen trap body to the bumblebee hive body, there is a risk of bees escaping and the researcher getting stung.It is important to place the trap closure into the trap before attempting this. Working under red light will further reduce the risk. Following pollen collection, the researcher can compare foraging preference, pesticide exposure studies, or environmental contaminant exposure studies.This technique has allowed us to compare bumblebee foraging to honeybee foraging behaviors, and it has been used to look at pesticide exposure of bumblebees returning to the nest with contaminated pollen.

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4.9K vistas.  Utah State University. This method allows researchers to collect pollen from bumblebee colonies with minimal disturbance to the bees and low risk of bee stings to the researcher. Using this protocol, pollen can be collected from multiple colonies simultaneously, permitting researchers to use more colonies with less labor and expense than hand collecting pollen. This method will benefit research in pollination and bee health, pesticide science and environmental contamination and can be adapted to multiple species of...