Hornet nests are marvels of natural engineering, attracting much interest from scientists. Hornets are the largest type of wasp, belonging to the same family as yellowjackets and paper wasps, the Vespidae.
Why Do Hornets Build Nests?
A hornet queen builds a new nest every spring to protect its colony and growing brood from the elements, such as wind, rain, and hail.
There is only one member of the previous colony capable of surviving winter and spring: the hornet queen. Upon emerging in the new season, the queen of the hornet sets up its new nest in a new location.
During the first round of worker hornet egg laying, the queen will build a small hornet nest, which is just large enough to accommodate her first batch of sterile female hornet eggs.
As soon as the worker hornets are fully developed, they will take over the hornets’ nest construction and continue to construct it until the fall. Queens are now solely responsible for producing more young.
How Do Hornets Build Nests?
A hornet’s nest is constructed of a paperlike material made from woody tissue fibers mixed with saliva. This creates a paper-mâché type of structure that looks like something akin to a party piñata. 
Hornets’ nests consist of three or four layers of open-cell combs enclosed within a thick, multilayered shell. Hornets are able to fly in and out through a single opening at the bottom. 
The queen builds the nest alone until the worker hornets are ready to take over, at which point they build a nest composed of three to four tiers of open-cell combs. As a result of this process, bald-faced hornet larvae emerge as adults after 20-25 days. 
The worker hornets cover the exterior of the nest with a paper-like wrapping that functions as an envelope or wrapper with only one opening at the bottom.
A bald-faced hornet nest may resemble an upright wine glass with a long cylindrical stem that serves as the nest’s entrance. 
Worker hornets continue to build the nest until the fall, when the number reaches between 300 and 1000. 
In the case of bald-faced hornet nests that are hangers, the nests are usually attached to branches or eaves through posts or petioles.
The powerful mandibles of worker hornets enable them to collect construction materials by chewing off or girdling bark and wood from the twigs and branches of various trees and shrubs.
The method of girding is used by European hornets to harvest bark from trees and bushes in the same manner as one eats corn on a cob. As a result of extensive damage, a branch may die entirely or in part if it becomes too girdled. 
Where Do Hornets Build Nests?
Nests of European hornets are most often found in tree hollows, but can also be found in barns, sheds, attics, or voids in walls. In general, European hornets will build nests in any cavity that is semi-protected.
The exposed portion of the hornet’s nest is covered with a coarse and papery material that is tan in color. A distinctive odor is reported to emanate from hornet nests constructed inside wall voids. 
Bald-faced hornet nests are typically located high up in tree branches and are well camouflaged. Their conical football-shaped hornet nests are made of paper material, which is similar to the nest material used by European hornets.
The bald-faced hornet’s nests are much larger than those of its wasp cousins, which can be as large as two feet in length and more than one foot in diameter.
Typical nesting sites for bald-faced hornets include trees and shrubs, manufactured structures, utility poles, and the eaves of houses and sheds. Between 100 and 400 hornets can be found in a bald-faced hornet colony at its peak. 
Why Do Hornets Build Their Nest Near People's Homes?
When there is a ready supply of food sources such as fruit drops, exposed garbage, and compost bins, hornets are more likely to build nests near homes.
The presence of a hornet’s nest too close to the home can be alleviated by maintaining a tidy yard, painting the eaves brightly, and caulking exposed cracks. 
Generally, bald-faced hornets prefer to nest under the eaves of buildings, on horizontal branches, or in a similar location well protected from the elements. The giant European hornet, on the other hand, is larger in size and prefers hollow trees.
How to Identify a Hornet's Nest?
A hornet nest may be identified by its woody, tissue-like construction, derived from tree branches. When completed, the hornet nest resembles a paper mâché structure or a piata. In most cases, they are conical, football-shaped, or teardrop-shaped. 
The exterior of the hornet nest consists of a strong envelope or wrapper made of the same paper-like substance with one opening at the bottom. Nests of bald-faced hornets may have a long cylindrical stem that serves as an entrance. 
How Long Will a Hornet’s Nest Last?
Every spring, a new hornet nest is started and a new colony is established by the queen. The hornets’ nest will last from early spring till late fall.
Like the rest of the Vespidae family, hornets live a seasonal life cycle from spring to late fall, with the exception of their queens.
Hornets do not reuse the nest from the previous year. Since hornets’ nests are made of paper, the discarded nests disintegrate quickly during the late fall wind and rain. 
Difference between Wasp's Nest and Hornet's Nest
Despite the fact that wasps and hornets use similar materials for nest building, there are several differences between their nesting techniques and habits.
In most cases, paper wasps build nests in the form of umbrellas under the eaves and overhangs of man-made structures. Depending on the species of wasp, nests may be left exposed.
Hornets, on the other hand, construct nests that are similar in size or larger than a football. It is common for bald-faced hornets to build their nests high up on the branches of trees.
As opposed than hornets, most yellowjacket wasp species prefer to build their nests underground. 
A bald-faced hornet’s nest looks like a gray wine glass hanging from the eaves of a building. A long cylindrical stem drops beneath the cup of the nest to allow access inside 
How to Prevent a Hornet's Nest
In order to protect their bushes from European hornets, homeowners may cover them with nets or spray them individually with a wasp or hornet spray. Pesticides are not available that can be directly applied to the bushes to control hornet nests. 
Among the most problematic areas for hornets and wasps are yards and homes that have many food sources such as dropped fruit, exposed garbage, and open compost bins.
Food sources should be kept out of yards, garages, barns, and porches to prevent wasp and hornet nests.
Caulking and sealing exposed cracks will prevent wasp nests from being constructed inside walls and in areas with high traffic in the spring. Eaves painted a bright color may also help reduce eaves hornet nesting. 
How to Safely Remove a Hornet's Nest
Chemical spraying is one method of safely removing a hornet’s nest. In order to achieve the most effective results, it should be attempted at night when they are the least active and the largest number of hornets are present.
The homeowner should take caution when spraying chemicals on a hornet’s nest by wearing protective gear such as thick, long sleeves and pants tucked into tall socks and covering any exposed skin.
If there is a hornet nest hidden in the wall void of a house, homeowners should not attempt to cover the outside entrance of the nest. It is possible that disturbed hornets will chew through interior walls to escape if they are unable to leave through their natural exit. 
In the event that homeowners are unable or unwilling to remove the nest on their own or cannot do so safely, they should consult a local pest control company.
All types of hornets will attack en masse if they believe that their nest is in danger. Unless there is a significant risk to humans, they should not be disturbed.
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