Wilderness Underfoot: The bald-faced hornet's winter strategy

StoryImage( ‘/Images/Story//Auto-img-117087877614079.jpg’, ”, ”);
StoryImage( ‘/Images/Story//Auto-img-117087891814078.jpg’, ”, ‘The hornets' nest — An abandoned nest makes an interesting display in a nature center, a classroom or the home of an aspiring naturalist. Hornets' nests can be collected in the winter after hard freezes have killed off the hornets. Before you bring it inside the house, leave it outside for a few hours just in case a wren or mouse has nested inside. After that, if you're still nervous about bringing it into the house, let it dry out in a garage, shed or enclosed porch. Any dead hornets inside the nest will quickly dry up. ‘);

By midwinter, although their nests may still be hanging in trees, these social wasps have long since died off.

Winter is the easiest time to spot the large bulb-shaped nest of the bald-faced hornet. This papery nest is usually found hanging near the end of a tree branch. During spring and summer, it is hidden by leaves, but by the end of autumn, the bulb stands out boldly against bare branches and blue skies.

If the sight of a hornets’ nest sends a chill up your spine, don’t fear. After a summer of hunting insect prey, drinking nectar from flowers, and building the distinctive nest, most of the colony comes to a fateful end in mass starvation and freezing. The colony’s only winter survivors, its young fertilized queens, abandon the nest in autumn, seeking a warm shelter for wintering over. In the spring, young queens will emerge from logs, holes in the ground, and human structures in search of locations for their own colonies.

Each queen starts by building a small nest with hexagonal chambers in which her eggs and larvae will grow. As the larvae develop into adults, they continue building onto the nest, adding layers through the summer.

Eventually, the nest may reach the size of a football, or larger. Its walls are made from chewed-up wood, paper and mulch mixed with the hornet’s starchy saliva. This structure is quite sturdy and resilient to weather. Even if the outside layer of the nest is soaked by rain, the inside remains relatively dry.

Although bald-faced hornets prefer building their nests in trees, they may attach a nest to a building or other structure. These insects are fiercely defensive, relentlessly stinging any poor creature, or human, that disturbs their nest.

Birds that winter over here—as well as white-footed mice—will often tear open hornets’ nests to get at the nutritious pupae and adult wasps that have been killed by the cold. Wrens and mice have been known to take up winter residence in hornets’ nests.

Despite their name, these social wasps are not true hornets. They’re closely related to paper wasps.

From the Feb. 7-13, 2007, issue

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