Bug of the Week

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National Moth Week is coming up July 18-26, 2015. To get ready, let's take a look a few of the different kinds of moths and learn how to recognize them.

There are some 11,000 species of moth in North America, grouped into many families.

1. Family Saturniidae - Wild or Giant Silkworm Moths

The giant silkworm moths are some of the largest moths. They have wide, thick bodies, like a person's thumb.

Examples:

Rosy_maple_moth(Public domain photograph)

The rosy maple moth exhibits the bright colors and thick body characteristic of this group.

atlas-mothThe atlas moth also has a particularly thick body. Other kinds of saturniids include luna moths, cercropia moths, and Polyphemus moths.

2. Family Sphingidae - called sphinx moths, hawk moths or hummingbird moths

Sphinx moths are also relatively large, but both their wings and abdomen are more pointed.

triangle-sphinx-mothThe wings and head form a triangle when a sphinx moth is at rest.

white-lined-sphinx-moth-bestThis is a widespread and common species, the white-lined sphinx moth.

rustic-sphinx-moth-side-houseThe rustic sphinx is another example.

Tobacco and tomato hornworm adults are also sphinx moths.

3. Family Erebidae -Tussock and Tiger moths

Note:  the tussock and tiger moths are a diverse group and they names are in flux. In the past, the tiger moths belonged to a separate family, the Arctiidae.

The most consistent characteristic of this family is that they hold their hairy front legs outstretched when they are at rest. Many of the subfamilies have striped or spotted wings.

hickory-tussock-moth-1This is a hickory tussock moth.

The Isabella tiger moth, the adult of the woolly bear caterpillar, belongs to this group.

4. Family Pterophoridae - plume moths

Although the members of this group are much smaller than the families above, they are very distinct because the moths hold their thin wings outstretched like an airplane.

plume moth1The typical T-shaped plum moth looks like this.

Next week we will continue with more moth families.

What is your favorite kind of moth?

 

This week let's take another look at the diverse community of insects found on the rush or desert milkweed.

Dusky Lady Beetle Larva with Aphids(Photograph by Lynne S., used with permission)

What do you see here? Probably the first things you notice are the bright orange-yellow aphids. Those are oleander aphids.

Dusky Lady Beetle Larva with Aphids on Milkweed(Photograph by Lynne S., used with permission)

But, what is the insect with the bright white fluffy look?

The insect that looks like a tiny white carpet is actually a lady beetle larva. Instead of the bright red-and-black lady beetles we usually think of, this larva will turn into a small dark brown or black beetle.

These nondescript beetles belong to a group called dusky lady beetles (Tribe Scymnini). The adults are round in shape, like other lady beetles, and feed on aphids, scales and mealybugs, too. The main difference is that the larvae produce a white waxy coating, which is thought to help protect them from predators.

Have you ever spot an adult dusky lady beetle or a larva? Where did you find it?

Right in time for Father's Day, we heard our first cicada singing yesterday.

cicada-side-good

It seems like the local Arizona species of cicadas always start singing the third week of June, or around Father's Day. They are highly predictable.

cicada-back-19

Of course our annual cicadas aren't as wondrous as the red-eyed periodical cicadas.

Snodgrass_Magicicada_septendecim(Public domain illustration by Snodgrass from Wikimedia).

You have probably heard about periodical cicadas. The adults emerge in large groups after long period underground. Some come out every 13 years. Others spend a whopping 17 years underground.

 

Magicicada_septendecim(Public domain photograph of 17-year cicadas from Wikimedia).

How easy is it to predict when a given insect will emerge or arrive in a certain area? The annual emergence or migrations of insects may depend on weather factors, such as temperature, winds, rains, etc. Those in turn change the availability and timing of host plants, which influence insect development. Insect emergence is often unpredictable, although scientists have created complex mathematical models to track certain pest species.

Cicadas, on the other hand, are protected underground. They also feed on fairly stable hosts, namely trees. Perhaps it is a combination of those factors that allow cicadas to be so predictable relative to other insects.

By the way, some broods of the periodical cicada are emerging in 2015, mainly along the Mississippi River basin area. Check Magicicada.org for more details and links to citizen science projects.

Are the cicadas singing where you live? Have you ever seen an emergence of the periodical cicada?