A wasp's nest, up close. (Photo: Matt/CC BY-SA 2.0)
The Vespula germanica species of wasps, one of the most common in the world, build nests that typically reach the size of a five-gallon bucket. They’ll house one queen and 15,000 or more wasps, and will not last through the winter—the queen wasp and her workers will die, and the next generation of queens will build new nests.
In places with mild winters, including Florida, New Zealand and North Africa, nests can survive for more than a year, though. That’s when they start getting big.
In Southampton, England, a wasp nest measuring six feet by five feet was found in the attic of a pub. In New Zealand, a nest described as “the size of a small car” hung from a campsite tree branch. In Florida, one entomologist was called to a hunting preserve to handle a nest 6.5 feet tall and eight feet wide:
That’s only about half the size of the largest wasp nest ever discovered, which measured approximately 12 feet by five feet by 18 feet, and was documented at a farm in New Zealand in 1963.
A nest that lasts into its second year can host multiple queens and more than 100,000 wasps in total. Over time, the rare nest that survives winters can accumulate dozens of queens. One giant nest built in a fold-down camper in South Carolina contained 37.
These freaky, hardy nests are horrifying in their size, but they also raise a troubling question: Is there anything keeping insects' nests from growing even larger? Absent human intervention, would they just expand forever?
The scientists to whom I posed these questions were both unfazed and reassuring. “Some species of wasps are just more likely to continue their nests than others,” says Bob Brown, who studies wasps in New Zealand. Most wasps just don’t have the same instinct to upgrade and super-size their homes that humans do. Only about five to 10 percent of V. germanica nests will last through winter, and the common wasp creates multi-year dwellings even more rarely. Across all 44,000 square miles of New Zealand’s North Island, Brown has heard of only one example.
More pressing, for insects, is dealing with competition from other colonies or natural enemies. This isn’t just true of wasps; the spectrum of eusocial insects—bees, ants, termites, and their ilk—has to watch out for challengers and predators.
A termite colony in Namibia. (Photo: Schnobby/CC BY-SA 3.0)
A termite colony can last for a decade or two once it becomes established, but most never do. Once a year, a colony releases a gigantic swarm of fertile offspring, says Scott Turner, an animal physiologist who has spent decades studying termite mounds. These homesteader termites drop to the ground, mate, and try to found new, competing colonies. “Nearly all of them die,” says Turner.
In this struggle for survival, size does help; one study of termite mounds found the largest were more likely to survive over the long term. A typical termite mound might be 6.5 feet tall, but they can grow to 20 feet, or more. Unlike your average wasp nests, termite mounds are long-term homes, and can stand for decades. There are physical limits to their growth, though. Sometimes, according to Turner, a section of the nest will be too far from water or other key resources—too much of a pain to keep up—and they'll abandon that wing.
Wasps and termites, then, have some checks on their expansionist impulses. But what about ants? One ant “mega-colony,” made of smaller, interrelated colonies, was said to stretch over 3,700 miles in Europe, and was later discovered to extend its domain across oceans, to Japan and California. Ants from these three mega-colonies recognized each other as kin: in experiments, they would attack other ants but not each other.
Given their vast terrain, is there any check on ant megalopolis growth? Well, by one measure, ant colonies are limited by the rate at which their queens produce offspring. If an ant colony is large enough, the queen will bear sexually reproductive ants who fly off to found new colonies, instead of workers who help increase the physical structure of the current colony. Still, the size of even a single underground city can be incredible:
As for the mega-colonies of interrelated ants, the only limit to their domain is time. Eventually, the geographically divided ants will evolve away from each other, and competition will begin again.