So many of us know the importance of pollinating insects, and indeed of insects in general which are the base of the terrestrial food chain. We've read about bees and butterflies that are struggling and realize that our small gardens, in their minor way, can collectively play a larger role in supporting the wildlife whose homes we share. When we see an insect foraging on a plant we purchased we are happy and feel fulfilled -- we are doing something good, and it is fantastic to feel good about that.
Looper moth caterpillar camouflaged in coneflower petals
So often, though, someone will say they saw pollinators on a plant -- which could be anything from a lavender to rattlesnake master to milkweed or daffodil. And then it's an open and closed case as that plant's presence is justified in the landscape as being ecologically important because something was using it. In the case of plants we especially find beautiful or unique, whether native or not, we rush to validate our preferences when it seems nature corroborates how we feel about a specimen. There's psychology at play here, something I discuss in my book A New Garden Ethic, about protecting ourselves in a world of mass extinction and preserving a sense of stability or safety in how we perceive the world. And that is what's partly at play in the defense of plants when an insect is seen using them. Of course it's an adult insect we're talking about here, not larvae eating leaves or other parts of the plant (without larvae there can be no adults, after all). Further, we're not often sure what kind of insect it is, and this is important to consider. Some questions we can ask about our backyard observations include:
1) Is this a native or exotic insect species? If exotic, is it pushing out natives? What role do those native insects play in the ecosystem compared to the exotic and what may or may not be lost as they are supplanted?
2) Is this a generalist or specialist species? Specialists are critical to the ecosystem and losing just one has a cascade effect that influences how well plants are being pollinated. Generalists, like bumble bees, will forage on just about anything. Also take honey bees: not only are they an exotic species that crowd out native bees and spread disease, they steal forage from native bees that native ecosystems (plants, etc) depend upon. That is partly due to their sheer volume, colony size, and range of several miles. A good number of native bees have a flight range of only a few blocks.
3) How is that adult pollinator using the plant? Is it foraging for nectar (fuel for itself) or pollen (essential food for its young)? What parts of the plant is it using (it's not just about the flower)? Is there evidence that any insect larvae are using the plant? Here we're commonly thinking butterfly and moth caterpillars, but also beetle larvae and much more will use the plant.
These are hard questions to answer, and if you can answer them you're now a bona fide backyard biologist who should be recording what you see to track how the climate and environment are changing. But simply, until we can answer these questions to some degree, our plants may not be as beneficial as we assume when we "see a pollinator" using it. It may very well be that the plant primarily supports insect species that are doing harm to other species, creating an unseen cascade effect that ripples out beyond the garden altering how nearby spaces function. If we can begin to understand that a garden is not its own self-contained place, but part of a larger whole, perhaps we will begin to ask harder, more honest, and more critical questions about what's using our garden and how we can improve the habitat so it's as pretty for wildlife as it is for us.
1) Is this a native or exotic insect species? If exotic, is it pushing out natives? What role do those native insects play in the ecosystem compared to the exotic and what may or may not be lost as they are supplanted?
2) Is this a generalist or specialist species? Specialists are critical to the ecosystem and losing just one has a cascade effect that influences how well plants are being pollinated. Generalists, like bumble bees, will forage on just about anything. Also take honey bees: not only are they an exotic species that crowd out native bees and spread disease, they steal forage from native bees that native ecosystems (plants, etc) depend upon. That is partly due to their sheer volume, colony size, and range of several miles. A good number of native bees have a flight range of only a few blocks.
3) How is that adult pollinator using the plant? Is it foraging for nectar (fuel for itself) or pollen (essential food for its young)? What parts of the plant is it using (it's not just about the flower)? Is there evidence that any insect larvae are using the plant? Here we're commonly thinking butterfly and moth caterpillars, but also beetle larvae and much more will use the plant.
These are hard questions to answer, and if you can answer them you're now a bona fide backyard biologist who should be recording what you see to track how the climate and environment are changing. But simply, until we can answer these questions to some degree, our plants may not be as beneficial as we assume when we "see a pollinator" using it. It may very well be that the plant primarily supports insect species that are doing harm to other species, creating an unseen cascade effect that ripples out beyond the garden altering how nearby spaces function. If we can begin to understand that a garden is not its own self-contained place, but part of a larger whole, perhaps we will begin to ask harder, more honest, and more critical questions about what's using our garden and how we can improve the habitat so it's as pretty for wildlife as it is for us.
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