Placing Artificial Domiciles to Attract Bumble Bees

Bumble Boosters

Lesson Plan Number 5 http://bumbleboosters.unl.edu

 

"Build a better bee-house and the world will beat a path to your door." Brady Beecham

Overview: In recent years, scientists have reported declines in the populations of many pollinating insects, including bumble bees. The availability of suitable nesting sites is a limiting factor for bumble bees, and several researchers have investigated artificial domiciles. So far, research about enticing bumble bees to accept artificial domiciles has been contradictory, inconclusive, and relatively unsuccessful. In this lesson, students will consider factors that could contribute to the establishment of natural nests. They will then be challenged to develop artificial domiciles and to evaluate their success in attracting nest site seeking bumble bee queens.

Project: Students will use a variety of materials to construct artificial domiciles for attracting bumble bee queens. Artificial domiciles will be placed in the field in the spring and monitored throughout the summer. Students will monitor domiciles for occupancy and determine which designs provide the most attractive artificial domiciles.

Vocabulary: hypothesis, variable, experimental design

Materials: Domicile construction: Consider how materials will withstand the harsh Nebraska summers. Use household or recycled materials like wood, plastic soda containers, cardboard, wire mesh, plastic tubing, etc. Some bumble bee species nest underground. Other species will nest on the surface. A shovel will be needed to bury nests that are placed underground. Flags made of wire with florescent tape are helpful in relocating nests. Students should maintain a journal that includes their design and observations.

Educational goals:

1. To elevate student awareness of the importance of pollinating insects and factors that effects their abundance.
2. To involve students in a "real" scientific investigation that will require critical thinking, creative design, collaboration, and networking.
3. To increase student ability in applying scientific method to design an experiment, test for variables, and evaluate data.
4. To increase student skills at presenting and publishing the results of a scientific investigation.

Scientific goals:

1. To develop strategies to increase the nesting success of bumble bees that can be implemented by farmers, gardeners, orchardists, and conservationists.
2. To determine the nest selection criteria that are used by bumble bees.

 

 

Introduction:

Developing a highly attractive artificial domicile for bumble bees has many important applications. It would allow humans to increase populations of bumble bees and the plants that benefit from their pollination. An attractive artificial domicile would also be invaluable to researchers who study bumble bees. Two methods of establishing bumble bee colonies have been investigated.

In the first method, a queen is collected soon after she emerges from hibernation and confined in a nest box. In the mid-1980's, a Dutch company developed techniques rearing bumble bees in captivity. Some of the information on rearing bumble bees in captivity has been published, but much remains a trade secret. Colonies reared in captivity sell for around $250 and are extensively used in greenhouses to pollinate cucumbers, tomatoes, and other crops. The second method of establishing colonies is to attract queens to artificial domiciles placed in natural settings. This is a less labor-intensive method and is better suited for small-scale pollination and observation. Researchers have not found a reliable way to attract nest seeking bumble bee queens.

Declining pollinator populations have increased interest in developing a reliable method to attracting bumble bees to artificial domiciles. During the last century, researchers tried many artificial domiciles designs with little success. You can think of a highly attractive artifical domicile as the Holy Grail of bumble bee research. In its first year, Bumble Boosters cooperating schools placed 30 replications of 4 domicile designs in natural settings. The designs used were based on reviewing the literature and making domiciles that others had reported to be successful. Out of the 120 domiciles placed, none attracted bumble bees. The goal of this lesson is to have students study natural nests and to design more successful artificial domiciles.

The Lesson:

Step #1: Nests in Nature. Before designing an artificial domicile, it is important to know why queens select certain nest sites and what these natural nests have in common. Here are some helpful resources for starting students on the investigation process:

1. Use the poster of a bumble bee nest or video clip to show the elements of natural nests.
2. For a firsthand look, bumble bee nests can be located and dug-up. Nests can be placed in a box for further observation or relocated. Since locating a nest can be very time-consuming and requires protective equipment, this is not recommended for the classroom. If you choose to move a nest, read Sladen for a good description of what to expect.
3. The Bumble Boosters Web site has information about bumble bee biology, nest architecture, and nest selection.

One of the most important factors in the success of bumble bees is nest selection. Newly emerged queens will spend up to two weeks searching for a suitable nest site. Bumble bees do not create their own nest cavity, and they do not forage for insulating materials. A suitable nest site will be dark, dry, protected from predators, and have pre-existing insulating material. Bumble bees often select an abandoned rodent den as a place to initiate a nest. Locating natural nests can provide valuable insight about designing artificial domiciles. However, looking for nests is time consuming and may not be a productive class activity. If students observe natural nests, they should be encouraged to keep a journal of their observations to compare with observations of their classmates. Students should look for common elements in natural nests to guide them in designing artificial domiciles.

Step #2: Artificial domiciles. Researchers have tried to mimic natural nests by manipulating different variables. They have had limited success using a variety of artificial nest designs. Below are a few of the variables that have been considered by past research. Students are encouraged to include some of these variables while designing their artificial domiciles.

Variables:

1. Location of nests.
2. 1. Some species of bumble bees nest on the surface and others nest underground. To attract both types, consider designing some domiciles for placement on the ground and others for underground. Previous underground designs have been fitted with an entrance tunnel leading to the ground surface. Some species respond better than others to establishing nests in artificial domiciles.
3. 1. Nests must be dry. Bees will likely abandon a nest that becomes wet.
   2. Tunnels leading up from underground nests should not be slick because bees will have difficulty walking up the tube. Tunnels should also be wide enough for two bees to pass each other.
   3. Nests are usually in an area that provides foraging plants throughout the summer.
   4. Marking domiciles may help attract searching queens and allow them to more easily orient themselves to the nest. Researchers have painted nests, marked them with flags and placed logs over them in an attempt to aid the queen in finding the nest.
4. Domicile design.
5. 1. Artificial domiciles have been made of terra cotta, tin, wood, cheese cloth, wire mesh, plastic, concrete, soil and recyclable materials.
   2. The size of the artificial domicile cavity may be an important factor. Keep in mind that as a colony develops it may need more room to accommodate growth.
   3. Some researchers have put gravel or sand in the base of the nest to encourage drainage.
6. Time of year. Domiciles must be placed in the field by mid-March when the first Queens begin to emerge.
7. Scent of the nest. Bumble Bees are often found in abandoned rodent dens. It may be possible that the bees are attracted to a chemical message left by a previous rodent inhabitant or to the scent of another queen.
8. Protection from predators. Bumble bee nests are sometimes attacked by ants, mice and skunks. Hives can be protected from rodents by making their entrances large enough for bees to enter and exit freely, but too small for rodents to enter. About ¾" to 1" diameter is recommended.
9. Nesting materials. Bumble bees need soft insulating material to cover their nest. Instead of gathering it on her own, a queen chooses a site with pre-existing insulating materials like a mouse or birds' nest. Researchers have imitated natural nest materials with soft grass clippings, cotton, and compost material. Avoid nest materials such as wool that may entangle the bees' legs.
10. Human observation. Opening or rearranging a domicile early in the season may cause an established queen to abandon the nest. A good design will allow observers to check the domicile with minimal disturbance. After the first brood has emerged, the queen will defend the nest rather than abandon it.

1. If you choose to have an observation window in your nest, using red glass may minimize disturbance since bees cannot see red light.
2. Slow, deliberate movements while examining a nest will reduce the chance of a defensive response.

Step #3. Designing and building artificial domiciles. Students are encouraged to consider the above variables and observations of natural nests into account when designing their artificial domiciles. Here are some recommended steps for designing and building artificial domiciles.

a. Decide whether the domicile will be placed above or below ground.

1. Draw plans for the design of the nest. The reverse side of the data sheet can be used for the final copy of the blueprint.
2. Select artificial domicile designs. Students will generate many different designs. Focusing attention on a few designs helps to narrow down the variables involved in solving the problem. Voting or small groups are ways to choose a few designs for replication.
3. Gather construction materials for use in the artificial domiciles. Using recycled material is consistent with the conservation ethic of the project. They are also cheap and easy to obtain.
4. Make and test artificial domiciles. Placing a copy of each model out in the field for a few days will reveal design flaws. If the artificial domicile becomes wet or damaged, design modifications should be made.
5. Design Replication. Since this is a real science project, we encourage students to make several copies of each design to be placed in different locations.

Step #4. Placing domiciles in the field. Most successful artificial domiciles will be located in areas where bees have been spotted before. Within a test location, consider the placement of domiciles in relationship to other site characteristics i.e. streams, fence rows, trees, and buildings. In each location, it is important to conduct several trials with each artificial domicile. Drawing a map and placing a flag near domiciles will aid in locating nests later in the season. Taking photographs of artificial domiciles and surroundings during placement is a useful tool for recording data.

Step #5. Observing domiciles / Recording data. Domicile occupancy should be checked twice: spring and in the late summer. In the spring, queens are likely to abandon disturbed domiciles. Waiting until June 1^st to make first observations minimizes the chance for disturbance. Check in late July-early August to determine if the nest has been successfully occupied. Domiciles can be observed by watching the entrance of the nest for activity. It is important to remain 6-10 feet away from the entrance of the domicile to avoid a defensive response. If bumble bees are leaving or entering the domicile, collect, chill, and identify the specimen before releasing it. If after 15 minutes no activity is observed, approach the artificial domicile, open it and record what is inside. Use the data sheet provided with this lesson to record information.

Step #6. Review data / Evaluate domiciles. Talking about the attributes of both successful and failed designs can help identify the key variables in attracting queens to artificial domiciles. In these discussions, students will examine the variables and develop hypotheses about artificial domiciles. Remind them not to be discouraged if their nests are not occupied. This is a "real" investigation, and unlike teaching exercises, the answer is unknown. Scientific investigation often requires years of trial and error before problems are solved.

1. What variables do you think contributed to the success of nests that attracted queens?
2. Is there any one variable that successful domiciles have in common?
3. Do some species of bumble bees appear more willing to nest in artificial domiciles than others?
4. What variables do you think contributed to the failure of unsuccessful nests?
5. Was the location of your domiciles an important factor in their success or failure?
6. How would you improve the design of your artificial domiciles to better attract queens?

Step #7. Submit results. After data has been recorded and analyzed, send copies of data sheets, photographs, maps, and other relevant information to:

Bumble Boosters

Department of Entomology

202 Plant Industries Building

University of Nebraska-Lincoln

Lincoln, NE 68503-0816

Conclusion:

The lesson is concluded when students present their findings to their classmates. This lesson can serve as a springboard for future assignments involving the process of scientific investigation.

References:

For more information regarding the research of artificial domiciles please refer to the Bumble Boosters Web site - http://bumbleboosters.unl.edu

Alford, D. V. 1975. Bumblebees. London: Ebenezer Baylis & Son Ltd.

Free, J. B. 1955. The Division of Labor Within Bumblebee Colonies. Insectes Soc. 2: 195-212.

Frison T. H. 1927. Experiments in Rearing Colonies of Bumblebees. (Bremidae) in Artificial Nests. Biol. Bull. Woods Hole 52: 51-67.

Fry, R. E. and Medler, Jr. T. 1954. Field Domiciles for Bumblebees. J. Econ. Ent. 47: 672-676.

Hasselrot, T. B. 1952. A New Method for Starting Bumblebee Colonies. Agron. J. 44: 218-219.

Hobbs, G.A., Virostek, J. F. and Nummi, W.O. (1960). Establishment of Bombus spp (Hymenoptera: Apidae) in Artificial Domiciles in Southern Alberta. Can. Ent. 92: 868-872.

Hobbs, G.A., Virostek, J. F. and Nummi, W.O. 1962. Managing Colonies of Bumblebees (Hymenoptera: Apidae) for Pollination Purposes. Can. Ent. 94: 1121-1132

Holm, S. N. 1966. Problems of the Domestication of Bumble Bees. Bee World 47: 179-186.

Loken, A. 1949. Studies on Scandinavian Bumble Bees. (Hymenoptera, Apidae)/ Norsk ent. Tidsskr. 20: 1-218.

Plowright, R.C. and Jay, S.C. (1966). Rearing Bumble Bee Colonies in Captivity. J. Apic. Res 5: 155-165.

Sladen, F. W. L. (1989). The Humble-bee, its Life History and How to Domesticate it. London: Logaston Press.

 

Artificial Domicile Data Sheet

Placement Data

Domicile Design Name:

Date placed in field:

Exact Location:

Is the placement of the domicile on the surface or underground?

Insulating materials included in domicile:

Other information related to placement or design:

Nearby forage plants and approximate distance to those plants.

 

Spring Observation (June 1^st):

Date checked:

Is it occupied by bumble bees (yes or no)?

What is the species and gender?

Are there other inhabitants in the domicile? If so, what are they?

What floral resources are nearby? How far are they from the artificial domicile?

Other:

Summer Observation (July early-August):

Date checked:

Is it occupied by bumble bees (yes or no)?

What is the species and gender?

Are there other inhabitants in the domicile? If so, what are they?

What floral resources are nearby? How far are they from the artificial domicile?

Other: