Category: Bug of the Week (Page 191 of 218)

Bug of the Week: Sunflower Insect Update

Some of you may remember from the Academy of Science and Technology Blog Carnival 3 post that we are participating in the The Great Sunflower Project.

We got our package of lemon queen sunflowers (Helianthus annuus) in the mail, planted them and were pleasantly surprised when they started to grow like crazy.

sunflwer plant

This morning I’m happy to report the first bee. No, the flowers haven’t opened yet, but here is a tiny sweat bee resting on a leaf.

sweat bee

It is about the size of a pencil lead. It has been visiting nearby flowers. Can you see the pollen?

sweat bee

A parasitic wasp was also sitting on a sunflower leaf.

parasitic wasp

Are these insects merely resting in the warm sun?

A clue to what they may be doing comes from the black spots you see on the sides of the photos near the base of the leaves.

ants

Those are ants.

What are the ants doing? Now, many people might think the ants are “eating the plants.” In a way the ants are, but not by chewing on leaves or harming the plant in any way.

It turns out sunflowers have extrafloral nectaries. As I explained in a previous post,  extrafloral nectaries are structures on the plant in places outside of flowers that provide nectar for insects, often ants.

Ants of the Southwest some great photographs of ants sipping nectar from the extrafloral nectaries of a sunflower. Photo 1 and Photo 2. Notice how hairy sunflowers are.

Sometimes bees and wasps may take advantage of the sweet liquid nectar as well.

Just think, insects get their breakfast from a plant and not a flower in sight.

Bug of the Week: Paper Wasp

This morning it has been partly cloudy, but during a burst of sunshine I was able to catch a photo of this paper wasp, Polistes flavus.

paper wasp

Any idea what she might be doing?

paper wasp

Look how shiny she is. Her eyes are shaped like kidney beans. She has three smaller eyes called ocellae in a triangle at the top of her head.

She was hunting for caterpillars and other insects. Wasps feed their young larvae bits of insects they catch and bring back to their extraordinary paper nests.

You might wonder whether I was in any danger taking this photo. In fact, this species of paper wasp that we encounter in Arizona is surprisingly unassuming. Unless you directly threaten their nest, they are not likely to sting. Their nests are often hidden in the dense foliage in small shrubs, such as rosemary bushes or under red yucca (hesperaloe) in our yard. We are much more likely to be stung by bees than these wasps.

I have noticed several paper wasps around my mint plants lately. I hope they are catching the cabbage loopers that have been devastating the plants. Go wasps, go.

Bug of the Week: Spider Mite Predators

In a previous post about hollyhock visitors, I mentioned the plants had spider mites. I wondered when the spider mite predators would show up. Turns out I didn’t have long to wait.

Spider mites are barely visible with the naked eye, and many of the beneficial insects and arachnids that feed on them are also incredibly tiny. In fact, I wished I had a microscope instead of a camera this week. Let’s take a “look.”

spider mite destroyer beetle

Those grayish black circles towards the top are lady beetles, but not the large orange and black ones like you might expect. These are called spider mite destroyers (Stethorus picipes). If you were not looking closely they might look like a bit of dirt or tiny seeds on the plant leaf. I can tell they are lady beetles by their rounded shape.

spider mite destroyer beetle pupa

The lady beetle larvae are on the plant feeding on the spider mites as well, as evidenced by the greyish pupa lying along the middle of the leaf.

You can see more of the life stages at the UC Davis IPM Online site.

red mite

A large red mite like this one might seem to be a bigger version of a problem mite, but it is actually a beneficial predator of spider mites. When you see single red mites that are readily visible and actively crawling about on leaves, that is probably a predatory mite feeding on plant mites or small insects. Mites have round bodies and eight legs.

minute pirate bug

Other point-sized predatory insects on the hollyhocks are minute pirate bugs (Orius tristicolor). (That is “minute” as in small, not the word for time.) The adults are black and white.

Minute pirate bugs feed on a number of small insects and mites. Here are some young pirate bugs or “nymphs” feeding within the webs of the spider mites. The nymphs are orange.

minute pirate bug nymphs

For a better look at the life stages, try this biological control page.

I didn’t get photos, but there were also some predatory thrips eating spider mites. Thrips are often thought of as plant pests, but some species are predatory.

It is great to see all the beneficial organisms having a banquet of spider mites. And I didn’t have to do anything except watch the show.

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