Tuesday, August 25, 2009

The Hornet's Nest

The fallen 12" wide hornet's nest showing some of its internal structure

A friend gave me a large hornet's paper nest the other day. She had found it last summer when she got stung while mowing her lawn. The nest was up on a tree, hanging from a high branch. After that she was weary of approaching the general area but did nothing to remove the nest and didn't suffer any further attacks. When Fall came, a strong wind broke the branch and brought down the paper nest already abandoned by its inhabitants.

When she gave me the nest, she asked me a few questions while we both marveled at its craftsmanship. There are several species of wasps referred to as hornets. They build paper nests up on trees using chewed pieces of vegetable material that hardens and becomes the consistency of paper.

The nest's envelope and cells are paper made of wood fibers mixed with wasp's saliva and applied in layers. The different colors show the variety of sources used in the construction

This is what Bugguide has to say about the life cycle of this particular kind of hornets: "A fertilized queen overwinters and starts a paper enclosed nest in the Spring. As the colony grows, multiple tiers are added, consisting of hexagonal cells. Males appear in the Fall." The Texas Agricultural Extension adds this information. And you can find a few more facts in the Fairfax County Public Schools website.

Hornet's stings can be very painful and they are more likely to attack when you happen to be close to their nests; that is where the expressions "mad as a hornet" and "hornet's nest" come from. Also, they can make nuisances of themselves, especially in the fall when they boldly approach any food available at picnics. Most people don't want to know anything beyond that; hornets are to be feared and avoided. An exterminator is the first thing that they think of when finding a nest in their properties.

But, there is another side to the story, worth examining. Hornets are omnivorous eaters whose diet seems to know no limits, but it can be grouped in two types: food for the adults, mostly sugary materials to fuel their flight and food for the growing babies, rich in proteins needed for building new tissues. They obtain the sweet materials from a variety of sources, from flower nectar to spilled soda on a picnic table; but mostly from the first. Thus, in their frequent visits to flowers they carry pollen from flower to flower and accomplish pollination. Although not as efficient as bees they deserve recognition for their job as pollinators. When it comes to feeding their babies, their diet is just as varied as the sugary one, ranging from living insects to cooked meat; from flies to bacon and hard boiled eggs. But, ordinarily, the main source of the baby food is insects that they catch in large numbers. They pounce on their prey, chew on it turning it into a pulp and feed this mush to the growing larvae in the colony.

An adult resident hornet. This one can't sting because it is a male

I would like to think that they specialize on harmful insects and leave beneficial ones alone; but, of course, this isn't true. They are equal opportunity predators and quickly attack anything available from honey bees to flies or caterpillars; as well as taking advantage of any dead meat available, be it a dead mouse or table scraps. However it seems that the bulk of their prey is made of all sorts of flies, house flies, blow flies, robber flies, flower flies, and everything in between. Many years ago a researcher counted 227 flies caught in an hour by a relatively small colony of about 60 wasps.

Caterpillars also figure prominently in their diet; once again they attack a wide range of species from butterflies to moths. Tent caterpillars are among the undesirable pests that they prey on; they may also feed their babies on Luna moths or painted ladies.

They have other connections with the rest of the living world. Some birds, such as the red eyed vireo use paper fragments from abandoned wasps nests to insulate and decorate their nests. Finally, hornets themselves are part of the food chain, providing nutrition to a number of other creatures, birds such as fly catchers, toads, bats, raccoons, etc. They are part of the web of life, linked to the plants they pollinate, the prey species they control and the species that they nourish.

My friend was wise in letting the wasp nest follow its natural course, rather than calling an exterminator. The busy hornets took care of countless insects all through the summer.

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© Beatriz Moisset. 2013

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