“Our Future Flies on the Wings of Pollinators”
Jan 12, 2008
This is the slogan for one group (www.pollinator.org) that is trying to increase public awareness about the immense value of pollinators and of the risks inherent in their population declines. It is reported that one mouthful in three that we consume is the result of insect pollination. Twenty-five percent of all birds eat seeds and fruit and are dependant on insect pollinators. It is a sobering thought to realize the interconnectedness of insects and our food supply and their value to the health of ecosystems worldwide.
Canada has approximately 1000 species of wild bees plus thousands of species of pollinating flies and beetles but most people only consider the introduced honey bee when they think of pollinators. Honey bees are good pollinators of many plants due to their vast numbers when a hive is placed nearby. Quite a number of our flowering plants are not well pollinated by them though as some plants require a specialised buzzing or a kind of bug dance to ensure the flower releases its pollen. This is an evolutionary tactic that ensures the right insect partner will transfer pollen to the same species of plant rather than randomly over a field of many different types of blooms. Honey bees are apt to be less discerning in their plant choices and can fly over a much larger range. This means they might be visiting many different species of plants and not necessarily ensuring cross pollination. Native bees and other insect pollinators often stay within 100 m of their nest site. A single female blue orchard bee (aka mason bee aka BOB) can visit 60,000 blossoms in its short lifetime. Native bees however do not produce honey.
Our honey bees are under serious threat from introduced mites and pathogens. Feral honey bee colonies have been all but wiped out in the East and only the attention and vigilance of bee keepers enables any hives to survive. These pests and diseases have also infected some native bees, but many are not showing signs of infestation.
What is affecting native pollinator populations are the usual consequences of our urban spread and agribusiness: habitat loss, fragmentation of the landscape so that natural areas are widely separated from each other, pesticide use, introduced species and diseases and monoculture food production all contribute to the decline of our wild pollinators. Many species make nests in woodpecker or beetle holes or fissures in dead wood or even underground, sometimes in abandoned mouse holes. When we tidy up our yards and parks so that there are no dead and dying trees and deeply till the soil, then we are forcing these species to seek more favourable living conditions farther and farther from our gardens and farms. When we grow a single crop, there is usually not a long enough floral season from the single crop to sustain the pollinators. They need different plants blooming throughout their life cycle in order to feed and survive.
Pollen comes in two general varieties. A very light, dusty pollen that is found in grasses and conifers is wind dispersed, while the heavier, sticky pollen, found on tomatoes and blueberries and most flowering plants is distributed as insects pick it up on their hairy bodies and move it from plant to plant; smooth bodied insects are not generally good pollinators. The sticky variety of pollen is rich in protein, starches and vitamins and is used by many species to feed their developing young.
Many people are considering our native blue orchard bees to be a major tool that can be used to pollinate our food and esp tree fruit crops as the honey bee populations decline further. BOB’s as they are also known, are solitary bees that can live adjacent to each other in bee condos. They are adapted to our environment and will fly earlier in the year than honey bees even in our adverse weather conditions. They’ll even fly in a light drizzle, surely a true west coast creature! BOB’s begin flying when the temperature reaches 14ºc, usually in the first two weeks of March and continue through the tree fruit season,
Solitary bees are described as gentle and non-threatening creatures that you would need to squeeze between your fingers before they will sting. The blue orchard bee looks somewhat similar to a house fly, only with a more rounded, smaller body (.5 in) and an intense cobalt blue abdomen. True flies have one set of wings while bees have two sets, although sometimes the second set can be hard to make out.
Some hover flies are excellent pollinators and can be recognized as they hover over a flower like a hummingbird; bees and wasps cannot hover. There is another species of blue orchard bee (Osmia texana) known as the berry bee because of its predilection for raspberry, blackberry and loganberry flowers. These bees fly a little later in the spring, usually around mid-May when BOB’s are just finishing their services. Apparently they will nest in similar bee condos and it might be worth building some bee condos and putting them out later in the spring for these pollinating helpers. Our native bumble bees are also invaluable for their pollination services, there are known to be at least ten species here on Southern Vancouver Island. Bumble bees do form small colonies and are known to sting if they feel threatened. I inadvertently stepped on a nest during a walk through Devonian one year and although the air was alive with bumble bees, none of them seemed to consider me a threat. In fact no one I was with received a sting (quite unlike a similar experience with hornets-ouch!).
Do you have some fruit trees that are miserly with their fruit production? Is a cool, wet week in February or March limiting the honey bees ability to pollinate your trees?
On my own property I have some plum, apple and pear trees that only rarely produce bumper crops. Since the resident bear is much more attuned to their peak ripeness stage and quick and diligent to harvest them, bumper crop or not, I rarely manage more than a single pie from my trees.
However, if you are not growing fruit for bears, you might consider creating some habitat for our native pollinators, adapted to life in our soggy spring climate. Derek Wulff is offering to show anyone how to construct a blue orchard bee condo on Monday February 25, 7 pm at the Community House. You need a large plastic pop bottle which will be painted, some cotton batten or upholsterers cotton (they often give scraps away for free), newspaper to roll into straw shapes, some cardboard, elastic bands and masking tape. Bee condo tubes are made from rolled newspaper and must be at least six inches long. The female will lay fertilized female eggs at the furthest end of the tubes and unfertilized male eggs at the nearest end; if the tubes are too short, she will only lay male orchard bees. The males hatch first and hang around the entrance waiting for the females to emerge and mate, like teenage boys around the 7-eleven!
Some pollinators use the hollow stems of the common reed (Phragmites australis) as nurseries for their young. Apparently the stem walls are thick enough to curtail certain parasitic wasp species from infesting the nests. That is also why rolled newspaper is appropriate for the tubes that the females will use to lay their eggs, they can rolled thickly enough to prevent the wasp ovipositors from reaching the juvenile bees. The wasps are able to penetrate the walls of plastic and cardboard straws and lay their eggs on developing mason bees. There will need to be a source of mud nearby that the females use to plug their constructed cells and nests. The developing young will complete metamorphoses in the nests by July but remain in the tubes until early spring. The nests cannot be moved or jostled until after July, if an egg falls from its mooring, it will usually die. Mite populations build up over three years and dedicated gardeners will need to clean the cocoons of dormant mason bees in the fall. This is easily done as the mites are on the outside of the cocoon and can be washed off with warm soapy water without damaging the bees. The bee condos should be placed where they receive morning sun, but protected from hot weather by a shaded overhang.
You can help our declining populations of pollinators by planting pollinator friendly flowers and enhancing pollinator habitat (from Lifecycles website).
• Native pollinators tend to be attracted to blue, purple and yellow single blossom flowers.
• Flowers with short tubes or no tubes at all are more likely to attract a variety of bees.
• Short-tongued bees and hover flies are attracted to small shallow flowers such as in the mustard family (beautiful bitter-cress and sea rocket), carrot family (springold and fennel), and sunflower family (daisies and asters).
• Long-tongued bumble bees are attracted to flowers with deep corollas and hidden nectar spurs such as larkspur, columbine, snapdragon, bergamot, delphinium, bell shaped flowers, mint and tomato family.
• Leaf cutter bees are attracted to beans and peas (legume family).
• Use native flowers and heritage varieties.
• Construct and install nest for pollinators for pollinators in your backyard. There are many designs for nesting boxes for species such as mason bees and hunting wasps.
• Learn to identify beneficial insects and their nest sites and let them flourish in your garden. This allows for a balanced population of spiders, ladybugs, bees and other beneficial insects to fight against the pests in your yard.
• Provide a water source, like a birdbath, small pond or a dripping faucet which insects can access. Bees need to drink clean water too!
• Provide mud for mason bee nests by digging a hole as wide as a shovel, past the organic layer and into the mineral layer of the soil. The mineral soil can be easily packed by the mason bee.
• Leave dead wood in your backyard. Dead wood provides shelter and nesting space for many beneficial insects, including leaf cutter bees and mason bees. They make their homes in old beetle burrows. Entire trees or even branches will suit this purpose.
• Keep some empty in your yard. For bees that keep underground nests, it is important to keep a small patch of uncultivated and undisturbed ground which is accessible to them.
• Flower food can be added to your yard by planting high nectar-producing plants each year. Native plants are great for indigenous pollinators!
• REDUCE PESTICIDE USE. Look towards other options first. Organic controls such as soap sprays and pest control techniques with natural parasites are good starters.
articles by Rex Welland of Victoria
The Forgotten Pollinators by Stephan Buchmann et al
Monday, October 13, 2008
"Our Future Flies on the Wings of Pollinators"
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