# Presentation: 506266

## The Art of Pollination in Cages with Insects

- “Everything there is to know about the bees and flies used in controlled pollination cages at NCRPIS, Ames, IA”

- S.J. Hanlin and S.G. McClurg
- Entomology Project    November, 2005

## Why do we use insect pollinators ?	

- 	The NCRPIS maintains collections of diverse germplasm.  Controlled pollination of individual accessions helps retain the original genetic diversity of the plant populations.  **Some plants are more effectively pollinated by insects than by hand.  In addition, insects may be more economical than hand pollination of some crops.**  At NCRPIS, insect pollinators are added to caged accessions of B*rassica*, miscellaneous umbels, sunflowers, and vegetables, as well as some ornamental and medicinal species.

**Notes:**
-Why do we use insects as pollinators at NCRPIS?
-We have found from years of observation and research that some plants are more effectively pollinated by an insect than by hand pollination and many plants have made adaptations so that pollen can be transferred via insect.
-In some cases we have found that using an insect to pollinate a group of plants is more economical than having several people hand pollinate the same size plot. 

## Primary insect pollinators used at NCRPIS

- Honey bees or *Apis mellifera*
*Osmia lignaria* or blue orchard bee and *O. cornifrons *or hornfaced bee
- Bumblebees or *Bombus impatiens*
- Houseflies or *Musca domestica*
- Blue bottle flies or *Calliphora *sp.
- Alfalfa leafcutter bee or *Megachile rotundata*

**Notes:**
-We use a wide variety of insects to do our pollinating at the station in a wide variety of situations.
-Over the years all of these insects have been used very successfully in combinations or by themselves as pollinators for the plants we grow in Ames.
-We would like to now look at each of these insects individually, an overview of the management techniques which are used and some pros and cons of each of these pollinators. 

## Honey bees

- Social bee with 2 - 4000 bees/cage
- Brought to U.S. by European colonists
- Traditionally used to pollinate many different plants
- Forage best from 15 to 32 C (60 to 90 F); don’t fly when wind speeds exceed 25 MPH
- Rearing well established but costly due to equipment and regular care required
- $82.50 for single story nuc
- $86.75 for double story nuc
- Aggressive, sting

**Notes:**
-The first pollinator is the honey bee.
-This is the most widely used pollinator at the station. 
-It is a social insect meaning it has a queen and other bees who do the work and lives in a colony group.
-This bee works very well during most of the summer months. However it is not as good at pollinating in the early spring or late fall or in rainy windy conditions.
-the management of this insect is very well established.  However it does take a large amount of time to manage this insect thus making the cost fairly high.
-Another problem with this bee is that it can be aggressive and does sting.

## Honey bee management at NCRPIS

- Source of bees:  Maintain own colonies supplemented with purchased queens or packages in the spring as needed
- Work is done by controlled pollination supervisor and 2 to 3 crew members
- 6 outlying bee yards in the Ames, IA area
- 150 Parent colonies (3 story hives with 10 frames per story)
- 800 Nucleus hives (1-2 stories with 6 frames per story)
- Spring time
- Check health of overwintered bees
- Begin making specialized nucleus hives and queen cells in April
- Begin “nuc” placement into field cages
- Summer time
- Continue making nucs and queen cells until mid August
- Place nucs into field cages at curators request (ca 90 weekly)
- Feed weekly with corn syrup solution and pollen patty bi-monthly
- Fall/Winter
- Monitor bees for mites; treat as needed
- Combine or discard queenless or very weak nucs
- Move strongest nucs and 2-story parent colonies to overwintering building
- Winterize 3-story parent colonies left outside
- Clean and repaint vacant equipment

**Notes:**
-Most of the honey bees we use are hives that we maintain throughout the winter or over wintered.  However we do supplement these with purchased queens and bees or packaged bees in the spring.
-We begin raising queens and producing the nucleus hives in the spring (April) and may start to put in some nucs for pollination.  This increase our production during the summer months.  We produce queens usually until August and nucs into early September.   We do continue to put nucs into cages into October.
-During this time we also feed each caged nuc high fructose corn syrup and pollen patties.
-In the fall we prepare the hives and nucs for over wintering.  With the majority of our bees going into an indoor facility for most of the winter months.

## Honey bee use at NCRPIS

- Major insect pollinator utilized
- Placed in ca 800 cages per year
- Can be used year round
- Used in both field and greenhouse cages
- Used to replace *Osmia* in B*rassica* cages
- Used in conjunction with flies in umbels

**Notes:**
-We use approximately 800 nucs annually.
-The majority are used in field cages
-We not only use honey bees in our field plots during the summer, but we also use weak nucs in greenhouse cages in the winter and the spring.

## What is a “nuc” ?

- 	A “nuc” or nucleus hive is a smaller version of a normal honey bee hive.
- Structure of nuc
- One or two stories with bees on frames of wax comb
- Bottom board with specially designed slide that allows bees to fly either direction from the box (inside or outside of cage) or to be confined within the box
- Lid with feeding hole
- Contents of single story = 6 frames total
- 2 frames with honey/pollen
- 3 frames with worker bees and brood (bee larvae)
- Queen bee
- 1 frame of empty comb
- Weighs ca 20 pounds
- Contains ca 2000 bees
- 2 story nuc
- Weighs ca 50 pounds
- Contains 4000 bees
- Frames contain: Lower box has brood and     upper box has honey/empty comb

**Notes:**
-I have been talking about the nucleus hives, well what are they.
-These are small hives with 6 frames, they have a laying queen and in a single story contains approximately 2000 worker bees a double story such as pictured here will contain approximately twice as many bees.
-When we make these hives in the field we place in them 3 frames of brood or young bees with adhering adult bees and 2 frames of honey/pollen.  The extra frame is an empty frame with no bees on it.
-With the double hive the extra box contains 4 extra frames of honey with adhering bees.

## Honeybee positioning into two cage sizes

- Nucs are generally placed in the northwest corner or north end of the cage.

**Notes:**
-When we place the nuc into cages it depends on the size of the cage they are going into.
-In the smaller cages we place the nuc half in and half out to allow for feeding of bees.
-In the larger sunflower cages, the double story nuc is completely placed into the cage.
-We always place the nuc into the north end of the cage, this encourages the bees to move throughout the cage because of the spring/summer sun.

## Slide 9

**Notes:**
-This graft just shows the number of honey bees we use compared to the overall bees that are used at the station.
-Honey bees have been used longer than 1999, however this is the time that I took over the project.

## Osmia

- Solitary bee; ca 40 bees per cage
*O. cornifrons* brought from Japan in 1977, *O. lignaria* native to U.S.
- Excellent for early season plants (*Brassica* and fruit trees)
- Will work 10 to 32 C (50 to 90 F) during the spring
- Rearing is established; cannot be manipulated further
- Cost $17.50/small domicile
- Cannot relocate domiciles from original placement during pollination season
- Non-aggressive

**Notes:**
-The little Osmia bee.
-This unlike the honey bee is a solitary bee, meaning that it lives and works by itself. 
-We use only 40 bees per cage to do the pollinating.
-This is the bee we use for all of our early blooming crops mainly the Brassicas but we have used them on early blooming shrubs.
-Rearing is fairly simple and thus the cost of use is fairly low.
-It is non-aggressive and does not sting.
-Several problems with this bee is that by July it goes into hibernation and must be replaced for further pollination and once it is in a cage, the domicile can not be manipulated in any way or the bees become disoriented and dies. 

## Osmia management at NCRPIS	

- Source of bees:
- NCRPIS increase from 6 outlying locations and from small field cages
- Ca 1500 to 2500 bees are purchased annually from supplier in the U.S.
- Domicile is PVC pipe (5 or 7.6 cm diameter) suspended via eye-bolts from 1.25 m metal rod bent at 45 degree angle ca 1 m from bottom
- PVC end cap placed on back; front of pipe is cut at an angle to reduce weather damage to straws inside
- Small domiciles for germplasm cages contain 4 filled straws (ca 32 bee pupae) in bundle of 16 cardboard tubes
- Large domiciles for bee increase contain 5 filled straws (ca 40 bee pupae) in total of 23 cardboard tubes; front of domicile covered with mesh screen to protect from predators
- Bees need a source of mud for forming walls between cells in nesting straws
- Osmia domiciles are collected in early July and stored at 26 C (80 F)
- Domiciles must be handled carefully to prevent dislodging developing larvae from pollen balls within the nesting straws
- Nest straws will be invaded by a variety of Hymenoptera
- Mid-November straws are removed from domiciles and examined for bee pupae before winter storage at 4 C (40 F)
- In March straws are placed into new domiciles ready for springtime use

**Notes:**
-We do produce most of the bees which we use in cages for pollination however do need to purchase between 1500 to 2500 bees yearly to fill all of our needs.
-The domiciles are placed into the cages in April where they remain until July.
-We collect all of the domiciles out of cages in July and place them into storage.
-In November we sort out the straws with bees in them from the ones without bees and these are incubated.
-In March we make up new domiciles to use in cages

## Osmia use at NCRPIS

-  Used in ca 200 field cages of *Brassica* annually from April – June
- Can be used in cool greenhouse cages beginning in April
- Used for some miscellaneous umbels and ornamentals

**Notes:**
-This is an example of the domicile that is used and the parts of the domicile.
-We use approximately 200 of these a year mostly in field cages , however we have used them also in cages in our cooler greenhouses in the spring. 

## Slide 13

**Notes:**
-This is the graft showing the use of Osmia bees compared to the overall bee use and again remember almost all of this use is for only about 3 months. 

## Bumblebees

- Social bee with ca 50 bees/colony
- Use U.S. native species
- Excellent pollinator of many plants
- Work in rainy, cool (13 C or 55 F), windy weather
- Active for long hours
- Rearing is difficult so commercial colonies are used
- Expensive ($100 per unit)
- Mildly aggressive

**Notes:**
-The last bee I am going to talk about is the bumble bee.
-Like the honey bee it is a social bee with a queen and workers in a communal hive.
-This is probably the best and most versatile pollinator available.  They fly in a wide variety of weather conditions and pollinate a wide variety of plants.
-The problem is they are difficult to rear and are expensive to purchase.
-They also can be aggressive and do sting.

## Bumblebee use at NCRPIS

- Bumblebees are used in ca 10 cages per year
- Used mainly for ornamentals with trumpet shaped flowers as bumblebees have long tongues
- Used in both field and greenhouse cages
- Can be purchased year round but availability may be limited by demand
- Queenright colonies may be too aggressive in working cages with tender or few flowers; Drone colonies are more “mellow”
- Occasionally we collect “wild” bumblebees for temporary cage use; put 3-5 bees per cage which live ca 5 days

**Notes:**
-Because of these limitations, we purchase only on average 6 to 8 hives per year.  We do use a hive in several cages during the summer with good success .
-We use the bees mainly in ornamentals with large trumpet shaped flowers that require a long tongue bee to pollinate them. 
-We use them both in the field and in the greenhouse cages.
-We have also used not only the “queenright hives” (contain a queen and workers) but also “drone hives” which contain only male bees.
-Also in late summer we have collected wild workers and placed them into cages with good success.  The only problem is they need to be replaced almost every week because they have no home to go to.

## Slide 16

**Notes:**
-this is the comparison overall of bee use and as you can see even though bumble bees are such great pollinators they actually make up a small portion of our overall bee use on a yearly basis.

## Houseflies and Blue Bottle flies

- Place ca 200 flies per cage each week
- “Incidental” pollinators
- Work at average temperatures
- Rearing is well established; pupae are low cost, cost varies per number of pupae purchased
- Require pre-conditioning of pupae prior to cage release for good emergence; no care required for adults
- Non-aggressive but may be considered “irritating”

**Notes:**
Past research at our station showed adding 200 flies to each cage weekly was appropriate
Flies are considered incidental pollinators as they collect pollen on their body hairs and move it around the flower head in their search for nectar
Work at average temperatures
Rearing is well established; fly pupae are inexpensive compared to other pollinators
We found that it is best to pre-condition pupae before adding to cages for increased adult emergence
Flies will not harm human workers, but may be considered “irritating”

## Fly management at NCRPIS

- Fly pupae are purchased
- BBF from Idaho every 2-3 weeks; stored at 0 C (32 F) for up to 3 weeks
- HF from ISU Ent project picked up weekly; cannot be stored
- Fly pupae are incubated on a weekly schedule
- 2-3 days at 26.5 C (80 F)
- Half-pint paper cartons with screened lids
- Better adult emergence
- Fly pupae HOLDERS
- One quart plastic containers weighted with plaster and exit hole cut out at top
- Gives flies a place to hide during inclement weather
- Protects pupae from people entering cages

**Notes:**
We purchase BBF pupae from a supplier in Idaho
We set up a regular shipping schedule when flies are needed on an ongoing basis since BBF can be stored for several weeks without reducing emergence too much
We purchase HF locally; they can not be stored so are picked up weekly
Fly pupae are incubated for 2-3 days at 26.5 C in half-pint paper cartons with screened lids
We developed some pupae holders from 1 qt plastic containers weighted with plaster; these give adults place to hide in bad weather and protect pupae from workers entering the cages

## Use of flies at NCRPIS

- Flies are used primarily for pollination of *Daucus* and other umbels
- May use as “fill in” pollinator for other crops (e.g. *Erysimum, Crambe*) when bees unavailable
- Used in ca 40 greenhouse cages in the winter and ca 20 GH cages in the spring/summer
- Used in ca 80 field cages in the summer
- Flies are replenished  in cages weekly due to their short life span; live 2 to 3 weeks
- Using two species of flies together or flies along with HB has been shown to increase seed quantity and quality

**Notes:**
Flies are used primarily for the pollination of Daucus but may be used as a fill in pollinator for other crops when bees are temporarily unavailable
We use them in ca 40 GH cages in the winter, 20 GH cages in spring/summer, 80 field cages in summer
Flies will live ca 2-3 weeks, but we replenish them weekly to make sure there is an adequate population present when environmental conditions are unfavorable
Research on pimpinella and daucus showed that using two species of flies together or flies along with HB will increase seed quantity and quality 

## Slide 20

**Notes:**
Graph showing use of flies from 2003 -2005
Although they are used in few cages (considering all pollinators overall) annually, flies are used during much of the year.
Winter-Spring GH season is Jan – May, Field/Summer GH is May or Jun – Sep, Fall GH is Oct – Dec

## Alfalfa leafcutter bee

**Why use ALC ?**
**Pollinator to supplement honey bees**
**Wanted insect easy to rear with established management **
**Non-stinging preferred**
**Largest unmet pollination demands:**
**Wild cucumis in GH cages**
**Late-blooming wild-type sunflowers**
**Bee Biology/Systematics Lab, Logan, UT recommended ALC**
**TRAITS of ALC:**
**Solitary bee; use 20 to 40 bees per cage, replaced ca every other week**
**Introduced to U.S. from Europe ca 1930**
**Traditionally used for pollination of forage legumes and blueberries**
**Work at 26 C (80 F) or above but not frequently in cool cloudy or rainy weather, prefer dry sunny climate**
**Rearing is established; bees are low cost ($100/gallon) and require little care**
**Non-aggressive but will bite if squeezed**

**Notes:**
Why are we using ALC ?  We wanted to find another pollinator to supplement honeybees.
We wanted an insect easily reared, with management techniques established; preferred non-stinging; something that would fill the need of wild cucumis pollination in winter GH cages as well as field cages of wild sunflower which may bloom late in the season. 
Bee lab personnel in Logan recommended that we try ALC to meet these needs. 
We had used ALC previously in research as a comparison for other pollinators.
ALC is a solitary bee which means each individual female does all the work needed to provision nest cells and lay eggs by herself; they may live/work near other bees of the same species but do not help each other.
We supply ca 20 to 40 bees per cage and replace them every-other week as needed since the plants we are putting them on are not their “favored” pollen/nectar sources.  Traditionally ALC have been used for pollination of forage legumes and blueberries.
They work best at ca 26 C or above and prefer dry sunny conditions; they don’t work much in wet cool conditions.
Rearing of this bee is established; they are low cost ($100 per gallon of 10,000 cells) and require little care.
They are non-aggressive but may bite (which stings momentarily) if squeezed accidently.

## Use of ALC bees at NCRPIS is still in the research stage !

- Lab work done 2004-2005 showed ALC can be used as greenhouse pollinator in winter/spring
- Early emergence of bees from cells is possible, but bees will not live for an extended time until a springtime “trigger” occurs
- Continuous incubation allows for weekly replacement of bees
- Extended emergence test (into fall) is underway now
- We are collecting “bare bees” rather than releasing them with cells as growers do
- Parasitoids (tiny wasps, ca 3 species) are a problem/concern
- We can release a known number of bees per cage

**Notes:**
Our use of ALC for germplasm increase is still in the research phase.
In normal use by growers, ALC are incubated in Mar – Apr for field use in Apr – May.  They are released with their cells into fields and provided large shelters for nesting.
We wished to use the ALC outside of their normal season and have been successful in early and late emergence of bees.
Early incubation:
We have incubated cells starting in Jan for GH cages flowering in Feb.
Normally ALC will live for several weeks to months; early-incubated bees will die off within a week until spring trigger (vernal equinox ?) so continuous incubation of new cells may be necessary for this system.
Extended emergence: 
We are still getting bees to emerge in Dec but don’t know if they are working well or living long as we lack the appropriate plants to put them on.
Bee collection:
We have been collecting bees through an emergence box/collection dish system so that we can reduce the number of parasitoids (parasitic wasps that are common in the cells) that are released into our environment and also so we can release a known number of bees per cage. 

## ALC management: Cool (4 C or 40 F) storage and pre-incubation at room temperature

-  Cells obtained from Canadian or western U.S. suppliers stored in screen trays or vented jars
-  Cell depth should not exceed 3.8 cm (1.5 inches) for reduced mortality
-  Pre-incubation at 23-24 C (73-75 F) for several days prior to warm incubation

**Notes:**
ALC management: They require some manipulation of cells in the lab, but once those steps are accomplished, the bees themselves require no care.
Logan personnel feel the highest quality cells (fewest parasitoids, healthy bees) are obtained from Canadian and western US suppliers.
Cells are purchased by the gallon (1 gallon contains ca 10,000 cells) in early spring. 
The cells are stored in a refrigerated chamber until we are ready to use them. (4 C or 40 F).  
Cells need to be kept well-ventilated and at a depth of 1.5” or less to prevent excess heat build-up in the cells; we use screen trays or jars with vented lids.
Prior to actual warm incubation of the cells, they should be allowed to sit at room temperature for a few days to reduce stress.

## ALC management: warm incubation and bee collection

-  **Cells incubated for 30 days at 30 C (86 F) for complete bee emergence**
** ****First two weeks incubated in dark, then placed in chamber with limited light period**
** ****Bees collected daily; provided wood nest cell and sucrose soaked wicks**
** ****Retrieved ca 43 sets of bees (20 bees/set) from ca 2400 cells**
** ****Parasitoids are controlled with 24 hour black-light/water trap**

**Notes:**
Warm incubation of ALC cells at 30 C (86 F) for 30 days is required for complete bee emergence, so advance planning is needed to coordinate bee emergence with predicted flowering of crops.  This may be tricky with diverse germplasm, so ongoing incubation of new cells is required for a ready supply of bees.
The first two weeks the cells are incubated in a dark chamber.  
The third week cells are transferred to a wood emergence box in a chamber that is lighted for ca 5 hours daily.  
Emerging bees are attracted to the light and exit the box into the collection dish where 5% sucrose solution is provided via cotton wicks and there are layers of wood nest cells they can hide in.  Both of these items and limited hours of light allow the bees to stay calm and healthier until they are collected and transferred to field or GH cages.
This year we retrieved about 43 sets of bees (20 bees/set) from ca 2400 cells incubated weekly.
In the bottom of the chamber note the black light and water traps used to control parasitoids that are common in these cells.  This same type of trap is located in other rearing areas where wasps may exit cells held at room temperature.

## Domiciles seem important in extending life span and activity level of ALC bees

-  Female bees carry pollen; providing domicile encourages them to work flowers in order to nest
-  Cut disks from leaves and petals for nest cells
-  Manmade domiciles have evolved from wood to styrofoam blocks; some models we tried in 2005 field and GH

**Notes:**
Female ALC are thought to carry pollen; males primarily collect nectar.
In order to encourage female ALC to work flowers they would not normally be interested in, providing a domicile for them to build cells in gives them more incentive.
People should be aware that the ALC bees will cut nest disks from both leaves and flower petals for their nest cells.  Curatorial staff at Ames have not noted reduced seed production as a result of this cutting however.  There are preferences for some plants or parts over others for nesting cell disks.
A GH study last winter showed the ALC cut leaf disks primarily from alfalfa and roses when offered those plants along with buckwheat and common mallow.  All of these plants were suggested as plants attractive to ALC for pollination or nesting material.  The petals of a wild-type Helianthus annuus were also highly attractive to the bees in the cage.
These photos show the domiciles we’ve tried at the station this past year using manufactured styrofoam nest blocks with 0.6 cm diameter holes preferred by this bee and various wood frames or boxes.
We do not anticipate collecting the ALC cells created from our small germplasm cages; the quality may be poor due to few bees and non-preferred plant sources.

## 2004 – 2005 Field Tests

- 2004: Compared HB to ALC in cages
- 8 accessions
- No significant difference in quantity or quality of seed produced
- 2005: Compared HB to ALC with and without alfalfa nesting plant
- 6 accessions
- Seed processing is in progress

**Notes:**
In 2004, we received complete results from 8 of 10 accessions planted in the field in 5’x5’x20’ cages for each two treatments: honeybee (HB) and ALC.
Accessions tested are listed in notes section.  No significant difference in seed quantity/quality.
Accessions successfully tested included:
Ames 19069 Cucurbita pepo
Ames 26871 Cucurbita pepo var. ozarkana
NSL 53717 Cucumis melo subsp. melo
PI 358814 Cucumis sativus
PI 536476 Cucumis melo subsp. Agrestis
Ames 15714 Erysimum cheiranthoides
PI 263866 Brassica nigra
PI 470079 Brassica napus

In 2005, we added a third treatment to the test.  We wished to determine if planting a small amount of alfalfa inside the cage for bee nesting material, had any impact on ALC pollinating “foreign” crops.  Seed processing is still in progress, but in general it appears that the amount of seed in the two ALC treatments was similar for most accessions.
Accessions included in this test:
Ames 6100 Brassica napus
Ames 7833 Ocimum gratissimum var. macrophylla
PI 285613 Daucus carota
PI 414157 Cucumis sativus var. sativus
PI 601164 Cucumis melo subsp. melo
PI 615152 Cucurbita pepo

## Accessions ALC appeared highly attracted to in 2005 field/GH cages

- 	ALC seem to be most effective at pollinating small to medium sized flowers of a “flat” nature
*Angelica*
*Brassica napus*
*Cucumis *
*Daucus*
*Helianthus* (wild-type heads)
*Melilotus*
*Ocimum*
*Potentilla*

*Cucumis* photo courtesy of L. Clark, NCRPIS

*Daucus* umbel pollinated by ALC

**Notes:**
Because the ALC is such a small bee, they seem to be most effective at pollinating small to medium size flowers that are relatively flat or easy to move in/out of.
During the 2005 field season the ALC were added to a variety field cages (along with other pollinators) in the cucurbita, miscellaneous umbel, and horticultural field plots.  
The crops listed are those where ALC seemed very attracted to the flowers and were working much of the time when observations were made.

## International Pollination Symposium 2006

- July 23 – 27, Iowa State University, Ames, IA
- "Host-Pollinator Biology Relationships - Diversity in Action"
- http://www.ucs.iastate.edu/mnet/plantbee/home.html

**Notes:**
Before we close, I would like to extend an invitation to you all to attend the International Pollination Symposium at Iowa State University this coming July.  NCRPIS is helping to host this event.  Please take a flyer if interested or check the website.

## Questions ?