Native bees are important pollinators – extended play version

Claudio Gratton, Associate Professor
Department of Entomology
UW-Madison College of Agricultural and Life Sciences (608) 265-3762

Bees in Wisconsin. Claudio Gratton tells us about the types of habitats that attract native pollinators.




6:22 – Total Time

0:16 – How the landscape affects native bees
0:46 – Diversity of the landscape
1:07 – Examples of how natives bees need habitat
1:37 – Life of a pollinator
2:04 – Habitat needed by native bees
2:29 – What the research says
3:04 – Natives make up for honey bees
3:37 – What native bees look like
4:38 – Do native bees sting
5:01 – Why study insects
5:42 – How interest began in insects
6:13 – Lead out


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Sevie Kenyon: Claudio, welcome to our microphone. How do our landscapes affect pollinators?

Claudio Gratton: And what I mean by landscape is, basically what’s there. Is it mostly agricultural? Is it mostly wooded? If it’s agricultural, is it corn? Soybean? Alfalfa? Is it pasture? Is it orchards? If it’s non-agricultural, is it wetlands, or woodlands or areas near rivers? All of those things define, describe what our landscape looks like.

Sevie Kenyon: And how do those different landscapes affect the insect life there?

Claudio Gratton: The insects move around the landscape, and so they experience different aspects of that landscape as they’re moving around, looking for food, looking for shelter, looking for mates. So, what is out there in the landscape, which we have a lot of control over makes a huge difference for those insects.

Sevie Kenyon: And Claudio, can you give us some examples?

Claudio Gratton: For example, bees. There are a lot of native wild ,bees in Wisconsin: five to six hundred species. These pollinators are looking for food and so as they move around the landscape looking for food the kinds of crops or the kinds of wild natural areas that they have out there make a big difference to their ability to survive and provision food for their young.

Sevie Kenyon: Claudio, can you describe for us, perhaps, the life of one of these pollinators?

Claudio Gratton: Some of them are ground nesters, so what they do is, the females actually dig holes into the ground and they go down, as little as six inches, but maybe even down a couple of feet, and what they do is pupate inside these chambers underground, and then the next spring they will emerge looking for food, just like their Mom did. So, the ability of the landscape to have nesting habitats for them is really important.

Sevie Kenyon: Well, what kind of habitats do these native pollinators like to have for their nest?

Claudio Gratton: So, some pollinators actually nest inside of stems, inside of hollow grass stems. So, you can imagine that a landscape that has fallow fields or grasslands or things like that might be really beneficial for stem nesting bees. The ones that nest in the ground like soft grounds that don’t get tilled up all the time.

Sevie Kenyon: Claudio, what does your research tell you about these pollinators?

Claudio Gratton: The work that we’ve been doing suggests that grasslands, woodlots tend to have more pollinators. And, what we’re trying to figure out is whether the abundance and the diversity of those pollinators actually relates to something that the farmers may care about, which is increased crop pollination. It’s great to have species around just for conservation sake, but we might want to know if those species are actually contributing something to the agriculture that we’re trying to do.

Sevie Kenyon: Claudio, is it possible for these native pollinators to make up the difference for commercial pollination?

Claudio Gratton: We don’t really know the answer to that right now, but that’s exactly what we think may be happening. There are some places in Wisconsin where native pollinators may be so abundant that it’s possible that you don’t need to bring in honey bees. Or, that you may need to not bring in as many. 

So, it’s possible that these native, naturally occurring, wild pollinators are actually providing us a service that we are replacing with the rental of honey bee hives that actually cost us money to do that.

Sevie Kenyon: Could you describe for us the variation? What do they look like?

Claudio Gratton: So the five or six hundred things that we call bees, if you can imagine a honey bee, imagine now shrinking some of those to maybe half or a quarter the size. Imagine making them dark black and compact. Imagine making them twice or three times as big as a honey bee to look like a bumble bee.

So, they all have the same general look. Four wings, which are kind of membranous, kind of clear wings, they tend to be fuzzy, which is what actually makes them good pollinators. The pollen actually sticks to their bodies. The hairs on their bodies are especially designed so that they’re like, they have little hooks on them that actually grab and hold the pollen to them. That makes it possible for them to just bumble around a flower and actually pick up pollen as they’re doing that.

Some of them have stripes, yellow and black stripes on them. Some of them actually are metallic with these beautiful iridescent metallic blacks and metallic green colors that look like the rainbow sometimes when the light hits them just right.

Sevie Kenyon: Do native pollinators sting?

Claudio Gratton: Most bees will deliver some kind of sting if you are actually handling them or if you’re really harassing them, but the ones that are non-social tend to do this a lot less then the social ones. So, honey bees, bumble bees, which have a nest or a colony that they’re trying to protect will engage in these defensive behaviors. That’s where the stinging comes in.

Sevie Kenyon: Claudio what attracts you to this line of study?

Claudio Gratton: I love insects, first of all. The thing about bees and Lady Beetles is that they’re out there doing good for us. They actually provide a service for people. As we go out and change our landscapes and change the way they look, the way they’re configured, the things that we plant there, these potentially free services may be changing and so I love this idea, this project from the perspective of the insects and I really feel strongly about it from the perspective of us being able to manage these natural resources that are out there for us.

 Sevie Kenyon: Claudio, do you have a story about how you got this interest in insects?

Claudio Gratton: I think I may have been a classic boy running around with his butterfly net when I was a kid. Everyone goes through those phases I think. But, I had a particularly good teacher in high school who was an entomologist. He got me hooked on insects and the closer you look at them the more you look at them the more you’re wowed by their beauty, by their diversity by the way that they live the way they do things and I haven’t been able to stop learning about them.

Sevie Kenyon: We’ve been visiting with Claudio Gratton, Department of Entomology, University of Wisconsin in the College of Agricultural and Life Sciences, Madison, Wisconsin… and I’m Sevie Kenyon.

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