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Archive for November 3, 2015

Bald-faced Hornet Nests No Longer Inhabited (if you live where there has been a hard frost)

Mary Holland holding very large wasp nest, which was built above her houseIf you research bald-faced hornet nests you will find that their average size is often compared to that of a football or basketball. The maximum size is said to be between 14 and 18 inches in diameter, and up to 23 or 24 inches in length. The pictured nest (which hung 20 feet above the roof of my house) measures 14 inches wide and 29 inches long – far larger than the average hornet nest!

This entire nest was built in roughly four months. It was started by a queen bald-faced hornet that, after emerging from hibernation this past spring, chewed some wood fiber, mixed it with her saliva and created a few brood cells surrounded by one or more paper “envelopes.” She laid an egg in each cell, and fed the hornet larvae insects which she first masticated into tiny bits. When the larvae pupated and emerged as adult workers, they assumed the duties of nest building, food collection, feeding the larvae and protecting the nest, while the queen continued laying eggs in horizontal tiers of cells. This ongoing activity produced a colony of anywhere from 100 to 400 workers by the end of the summer. Shortly before the first hard frost this fall, the queen left the colony and found a protected spot in which to spend the winter. When freezing temperatures arrived, the workers all died, leaving a nest that will never again be inhabited by bald-faced hornets. (Thanks to Nick Burnham, who ingeniously managed to collect the nest for me, and Gary Trachier for the photo.)

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