Dirt Daubers Nests Are Built For The Young To Snack
By Les Harrison
Wakulla County Extension Director
Snack foods are a typical American part of the summer break from school and a vacation staple. There are so many from which to choose, each with its own unique flavor and texture.
In recent years, these well preserved (or petrified) treat have come under near constant criticism from a variety of professionals. There is concern about the effects of high levels of sugar, salt and trans-fats in the diet along with the absence of nutrients and soluble fiber.
Adults are susceptible to the hazards of these securely packaged menu alternatives, but the major concern is the long term effects on youth. While some of the human residents of Wakulla County fret over this topic, one native insect species has no such worries.
Dirt daubers, in the Sphecidae insect family, spend summers busily building nests, usually on protected locations of buildings and other human structures. As with all wasp species, the objective is to raise the next generation.
Unlike yellow jackets and ground wasp, this is not a social insect which will assemble in large colonies. Though not particularly aggressive, it is capable of a painful sting if provoked.
As an adult, it survives on drinking nectar. Like all wasp however, its larvae are carnivores which consume the tissue of other insects.
This stage of life is where this genus’ behavior truly distinguishes it from other wasp. It also justly earns its common name.
The females use local soil to construct nests in which to lay their eggs. Using moisture and their mandibles they construct single egg chambers.
There are two forms commonly encountered. One can be shaped like a pipe organ’s flutes or tubes, the other just an oval glob of dirt.
Nests are sometime multi colored. This variation reflects variations in soil types available for the individual nest constructions.
If in shielded sites, the hardened nest can last for years or decades. Once abandoned by the dirt daubers the nest can be used by other insects for bring up their young or as homes.
Once built, the females begin a provisioning process to assure the survival of their young. Spiders are the food source for the larval hatchlings.
Depending of the dirt dauber species, there are specific native spiders which are targeted to be on the young’s future menu. The female dirt daubers must protect the nutrient supplies from drying out and spoilage.
To overcome this challenge, she uses her stinger to immobilize but not kill the unlucky spider. In this state of suspended animation, the comatose spider is alive and a viable food source.
Unable to resist the dirt dauber, the spider is crammed into the egg compartment with others which fall prey to this winged predator. A single leathery egg is deposited in the cavity before it is sealed shut.
In the weeks following the egg’s deposit, it hatches and the larva is able to snack at leisure on the helpless spiders. When strong enough, the new dirt dauber bores out of the nest encasement to begin the process again.
While not likely to be found on the shelves of convenience stores, hapless spiders await their fate under the countless eaves and on exterior walls as well preserved healthy snacks for future generations of dirt daubers.