Category: Bug of the Week (Page 15 of 218)

Bug of the Week: Larvae Are Insects, Too

Do you know what this insect on a brittlebush flower is?

Not very attractive is it?

I’ll give you a hint. Remember the lady beetles we saw two weeks ago?

This bumpy creature is a lady beetle larva.

Even though people usually can identify an adult lady beetle, not as many people recognize lady beetle larvae. The larvae are impactful, however, because they eat way more aphids than the adults do. Plus, if they survive, they become an adult.

The bottom line is that taking time to identify insects in all their stages and forms is important.

Bug of the Week: Reactions to Genista Caterpillars

A few weeks ago a friend and I visited the Desert Botanical Garden. As we passed by a Texas Mountain laurel plant, I noticed a caterpillar.

Okay, maybe I knew where to look.

A couple of other people came by, and saw that my friend and I were peering into the bush. I was struck by how different their reactions were.

A young boy spotted one and exclaimed, “Look, a caterpillar!” Soon he had found one after another, excited at each one, pointing them out to us.

A man –probably his father– came up and said, “A pest.”

They walked on.

Obviously, each of us has a unique perspective. For example, I knew the insects were called genista caterpillars, Uresiphita reversalis, and when they finished development they would turn into a moth. I’ve seen genista caterpillars every year in the spring on Texas mountain laurel plants for over a decade. The caterpillars feed while the plant is flowering, then disappear–pupate and overwinter as a pupa — until the following year (see a photograph of an adult and a pupa). Generally the plant recovers after the caterpillars pupate, so no need to do anything about them.

Also, Texas mountain laurel leaves and bright red seeds are full of some noxious chemicals (toxic alkaloids). It is actually pretty amazing that the caterpillars can eat the leaves and survive. Genista caterpillars use the plant’s chemicals to defend themselves, like monarch caterpillars use the toxins in milkweeds to defend themselves. They are specialized to those plants.

Even though everything seems to be changing (the garden is now closed), there’s always hope that we can expect to see genista caterpillars again next year.

Have you ever seen a genista caterpillar?

Bug of the Week: Lady Bugs Need Plants

it is another case of “if you plant it, they will come.”

Right now the common desert shrubs called brittlebush (Encelia farinosa) are in full flower.

Many pollinators use the flowers as a source of nectar and pollen, including honey bees, butterflies, and flower flies.

In addition to the dainty little flower fly on the right, this flower has another visitor, an easily recognizable one. It is a lady bug, or more accurately lady beetle, of course.

Many of the flowers had lady beetles sitting on them. Why?

It is well known that lady beetles can supplement their diets with flower pollen, but these plants also offer something else.

Aphids!

Lady beetles are mostly aphid specialists. The larvae eat many aphids per day. The aphids feed on the brittlebush, which in turn feed the lady beetles.

The plants actually support two kinds of lady beetle. In the above photograph is the seven-spotted lady beetle, Coccinella septempunctata. Common in Europe, it was introduced to North America in the last century. As the name suggests, it has seven black spots on its forewings.

The species we encountered first is the convergent lady beetle,  Hippodamia convergens.  Native to North America, you can tell these beetles by the two “converging” white lines on the back of the thorax.

The number of spots on the wings of convergent lady beetles varies a lot and sometimes the spots are tiny/nonexistent like on the beetle in the photograph above.

Now you are an expert, can you figure out what species of lady beetle is featured in the header of this blog?

 Where did the lady beetles come from?

Lady beetles migrate.

Aphids are cool season insects, so here in the low desert they arrive in late winter and early spring. By summer the aphids are gone and so are the lady beetles. The beetles fly into the mountains where they may complete another generation and/or form large aggregations to overwinter. When temperatures begin to warm, they fly back to low lying regions to start the cycle again.

The bottom line is that without the brittlebush and without the aphids, we wouldn’t see lady beetles.

Are there flowers in bloom where you live?

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