CO-Horts

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Friday, June 28, 2019

Let's Celebrate Pollinators Every Week!


Posted by: Lisa Mason, Arapahoe County Extension

Last week was National Pollinator Week! We should celebrate pollinators every week because they provide so many benefits to humans and ecosystems! Many people are well aware that bees are declining all over the world for a variety of reasons including habitat loss, pesticide use, parasites, diseases, climate change, etc.

Pollinators include bees, bats, flies, beetles, wasps, ants, butterflies, moths and some small mammals. Bees are among the most efficient pollinators because the pollen sticks to the hairs on the bee.

Two-tailed swallowtail, Papilio multicaudata. Photo: Lisa Mason

Why should we care about pollinators?

Pollinators provide valuable ecosystems services. They transfer pollen grains from one flower to another which enables the plants to reproduce. Here is a closer look at the value pollinators have to humans and ecosystems.
  • 75% of more than 240,000 plant species rely on pollinators for reproduction. 
  • The global production of crops that depend on pollinators is an industry worth up to US $577 billion annually. 
  • Bees help to pollinate 1/3rd of the human diet including the most nutritious part of our diet—fruits, vegetables and nuts. 
  • In addition to crops, they pollinate the food for livestock that contributes to the meat and dairy industry.
Our planet has an incredible amount of bee diversity! Most of us are familiar with the honey bee (Apis mellifera), a non-native bee species to the United States. The honey bee was brought over from Europe in the 1600’s. In addition to the honey bee, we have approximately 20,000 species of bees worldwide. We have over 900 species in Colorado!

A green metallic sweat bee, Agapostemon sp. Photo: Lisa Mason
A leafcutter bee, Megachile sp. Photo: Lisa Mason

Where you can you find the bees?

Bees come in all sizes, shapes and colors. Take a close look at the flowers in your garden this summer. You are likely to see bees buzzing around in pollinator-friendly plants! To get an idea of the bees that are in your garden, check out the Native Bee Watch Citizen Science Field Guide.

When the bees aren’t foraging in flowers, the females are likely at their nesting site. Of all the bees in the world, approximately 90% are solitary bees which means they mostly do not interact with other bees with the exception of mating.  Of those bees, about 70% live underground and the other 30% are cavity nesters. Solitary bees have a one-year lifecycle.

Some bees are generalists or polylectic, meaning they collect pollen and nectar from a variety of flower species. These bees are opportunistic but still may prefer certain flowers. A specialist or monolectic bee only feeds on a specific plant species. Monolectic bees have generally coevolved with a specific plant species meaning the plant and bee depend on each other for survival.

A squash bee, Peponapis pruinosa. Photo: Lisa Mason

Do you enjoy pumpkins and squash?

If so, thank a squash bee! They are a great example of a specialist bee. In Colorado, we have one species, Peponapis pruinosa. Squash and pumpkin plants need these bees to pollinate the flowers so they can reproduce. They have special pollen collecting hairs on their hind legs that helps to transport the pollen. One research study showed that not only were squash bees more efficient at pollinating squash plants, but they pollinate earlier in the morning when pollen and nectar is readily available. By the time honey bees start foraging, the squash bees have already pollinated the flowers. If you look in the early mornings at the big yellow flowers on your squash or pumpkin plants, you are likely to see squash bees in the flowers.

Squash bees and other native bees need your help! By developing habitat in your yard, you can provide food, shelter, water and space for native bees and other pollinators. Check out this blog post on creating pollinator habitat. You can also check out the following fact sheets:

Have fun observing bees in your garden!

A cactus bee, Lithurgopsis apicalis. Photo: Lisa Mason

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