Protecting pollinators

They come in the familiar black and yellow but they also come in metallic green and metallic blue, some with few hairs, some hairy, some as large as a quarter while others are the size of a mosquito

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The honeybee is only one of about 20,000 species of pollinators around the world, many more of which have yet to be discovered. In the US and Canada, we’re looking at about 4,000 species, and only 900 of which are native. All species look and behave differently with the vast majority nothing like honeybees. We need to appreciate these differences in order to protect and support them.

Why are pollinators so important?

Angela Gradish is a research associate in the School of Environmental Science at the University of Guelph. As she explained at FarmSmart19 in Guelph, pollination is required for fruit and seed set. Plants may be self-pollinating or cross-pollinating with assistance from wind and animals: birds, insects and some bats provide the bulk of pollination services, including flies, wasps, butterflies and moths.

Angela Gradish: Pollinators are divided into two groups according to their diets

But honeybees are what we think of when we think of pollination, even though they are not native; they are considered the livestock of the pollinator world, reared artificially for use as pollinators and for honey. Without us, honeybees wouldn’t be here.

Honeybees depend on nectar and pollen as their only food source for their entire life cycle, therefore they are behaviourally and physically specialized. Their body hairs are positively charged, attracting pollen by static electricity. Modified structures known as ‘corbicula’ are used as pollen baskets on their back legs, creating a pollen pellet that is delivered back to the hive.

Pollinators come in the familiar black and yellow but they also come in metallic green and metallic blue, some with few hairs, some hairy, some as large as a quarter while others are the size of a mosquito. In bumblebees, even sisters can be a wide variety of sizes, with early spring emerged bees being larger.

Most bees aren’t very social. In 90 percent of species, individual females create a brood nest but provide no maternal care. Honeybees and bumblebees are ‘eusocial’, with a queen laying the eggs and sisters providing cooperative care. Worker bees will bite a small hole in the top of a cell holding larvae and regurgitate pollen and nectar into the brood chamber, then seal the top with wax. The adults will then stay close to provide warmth.

Where do pollinators live? Only honeybees live in the familiar wooden boxes. Seventy percent of pollinators dig holes or use existing holes in the ground, while cavity nesters will lay eggs inside a hollow reed, under rock piles or grass, in bee-made mud structures or in holes in the mortar of brick walls, in stumps, or in the case of carpenter bees, in chewed tunnels in your house walls. They’re versatile, said Gradish.

Pollinators are divided into two groups according to their diets. There are generalists, those such as honeybees and bumblebees that will collect nectar and pollen from hundreds of plant types, and specialists that will only visit one type of plant.

Squash bees, for example, are adapted to feed on all cucurbic flowers except cucumbers, coming out at dawn with the opening of the flowers from nests in the ground close-by.

Corn doesn’t rely on bees to pollinate, it does fine with wind, but the list is long for other crops that do need bees, including everything from asparagus, berries, broccoli, buckwheat, canola, carrots, cauliflower, cherries, and clover to peanuts and peas, peppers, soybeans, stone fruits, sunflowers, tomatoes, and tree nuts. Basically, everything but cereals needs bees.

Gradish cited estimates that pollinators contributed $29 billion to farm income in 2010, with a global value of $3,251 per hectare, of which a significant $2,913 per hectare was attributed to honeybees.

What can we do to protect these vital workers?

Gradish suggested paying attention to their habits and needs. Pollinators are generally most active from April through October, with a peak in June and July. Depending on the species, they require heat and light to fly. Some, such as the alfalfa leaf cutter bee, will shut down if clouds roll in; some can see under lower light and generate their own heat to fly. All activity is weather dependent, with activity increasing in the heat, to a point.

Louise Heyming: don’t mow the roadside at all if it’s only for aesthetic reasons

When it comes to pesticides, Gradish advises minimal use, carefully timed before dawn or after dusk when the bees are less active. The adults will be exposed while out flying; the larvae will be exposed by contaminated material brought back by the adults. Avoid applying pesticides near bloom and in cooler conditions that can increase the toxicity of the pesticide, and choose products that are less toxic to bees with less residual effect. Around the farm, choose manual removal of weeds instead of using herbicides on ditches and hedgerows.

Louise Heyming, Supervisor of Conservation Outreach at the Grand River Conservation Authority, joined Gradish, taking that suggestion one step further: don’t mow the roadside at all if it’s only for aesthetic reasons. Such areas provide habitat for pollinators, as do decaying wood, rockpiles, rodent burrows, and grassy areas. What do you already have, she asked? What can you enhance?

The garden is another obvious place to support pollinators, with simply leaving garden clean up until spring, providing an over-wintering home. Pollination strips in market gardens planted with native wildflowers will also help beneficial insects, and cover crops and riparian buffers provide food sources and nesting areas. Trees can be considered a food too, as well as providing a leaf litter home in either windbreaks or hedgerows. Even a single row of spruce can reduce windspeed to encourage foraging.

Look for opportunities on your own farm and find out if funding assistance is available to make your farm more pollinator-friendly through conservation authorities or the OSCIA.