Bees and Biodiversity

Bombus ternarius, Tricolored bumble bee on mountain mint

 Recently I discussed the idea of allowing dandelions on the lawn to benefit pollinators. I pointed out that such practice only benefits a handful of generalist pollinators, but not the specialists. The latter can be more numerous than the former when they are all counted. They also account for the wide diversity of nature.

Bombus impatiens, Common Eastern Bumble Bee on blanket flower

Andrena cornelli, Azalea andrena on azalea

Let me expand on the concept of biological diversity or, as it is often called by ecologists, biodiversity. There are 4,000 species of bees in North America, from the familiar, big and plump bumble bees to tiny bee species that remain unnoticed to all except to those who study bees. Bear in mind that even bumble bees aren't just one single species but about 46 in North America.

Augochlora pura on thistle

Nomada, cuckoo bee on spring beauty

Bee species vary not only in size but in many other ways. Some are active from early spring to the end of fall. Others complete their whole cycle in just a few weeks and remain dormant the rest of the year. Some are adapted to different climates and cover a large area, others are more limited in their geographic distribution.

There are even some species, called cuckoo bees, that don't bother raising a family. Instead, just as cuckoo birds, lay their eggs in the nests of other bees.

Some bees have a long tongue that enables them to reach into fairly deep throated flowers. Others can only visit flowers that are relatively flat and open. Finally, some are very particular about the flowers they visit.They collect pollen from only one species of plants (monolectic) or a few related species (oligolectic). They may visit a wider range of flowers for nectar, but only their choice plants will satisfy their pollen needs.

Agapostemon splendens on seaside goldenrod

Lasioglossum pilosum on coneflower

Losing a few of these specialists may not be catastrophic, but it is preferable to preserve as many of them as possible. A rich variety of species confers resilience to an ecosystem. This is why it is important to have a wide range of specialists along with the handful of generalists. One way to help the specialists is to plant a variety of native plants to ensure that some of them satisfy their needs.

Colletes on Cerceris canadensis

Bombus perplexus, confusing bumble bee on common milkweed

Long horned bee on sunflower

 All images © Beatriz Moisset

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Beginners Guide to Pollinators and Other Flower Visitors

© Beatriz Moisset. 2016
 

What is native? What is not? When does it matter?

Common milkweed, Asclepias syriaca (© B. Moisset)

Definitions of native plants abound. None is entirely satisfactory in all circumstances but each may serve a specific function. Some strive for scientific accuracy; others serve practical purposes. Moreover, in some instances the nativity of a plant may not matter to the native-plant gardener. None of us is about to give up growing tomatoes regardless of their non-native status.

Some important concepts lack a perfect definition. We need to name them, nonetheless. Biologists would be lost if they couldn’t use the concept of “species” just because no definition fits all the circumstances. This word is not only important but absolutely necessary. One may need to use different definitions of “species” depending on the discipline; but that is no reason to give up the word. The concept of “native” organisms is equally necessary. It is here to stay, regardless of the difficulties that may arise at times.

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© 2012, Beatriz Moisset. All rights reserved. This article is the property of Native Plants and Wildlife Gardens.

List of articles
Beginners Guide to Pollinators and Other Flower Visitors