These insects vary in size (from 10 to 55 mm in length) with an elongated abdomen held in place by the thorax by a slender and slender structure in the shape of a characteristic petiole called a “wasp waist”. They can be all black or brown, or dark with white, yellow or red markings. The front legs of females often have specialized structures for digging.
The larvae are pale and have no legs.
The Sphecid family once included the crabronids, a fairly similar group of wasps that now form a full family.
Sphexes are holometabolous insects . Their growth cycle consists of four different stages: egg, larva, pupa and adult. The female, generally solitary in her nest, captures spiders or insects that she paralyzes with her venom. It transports them to the nest, then lays its eggs on the prey which will serve as food for the larvae.
Some species are kleptoparasites: females visit the nest of another wasp and lay eggs on preys already captured. They thus leave their eggs on the host and take no care of their larvae.
Almost everywhere in North America.
These wasps build different types of nests depending on the species. Most species do this in the soil. The female can dig her own nest or use a hole already ready for use. Some build mud cells attached to stones, tree trunks or buildings. Others nest in plant stems or in dead wood.
The adults feed on the nectar of different plant species. The larvae are carnivorous.
What you need to know
This family of wasps has more than 720 species around the world, including 21 in Canada.
Depending on the species, adult sphexes feed on nectar, aphid honeydew or body fluids from their prey. The larvae are carnivorous and feed on the paralyzed bodies of the arthropods on which they were born. These are often grasshoppers, locusts, caterpillars and spiders . The females hunt solitary to ensure the subsistence of the larvae.
All species of sphex can inflict a painful sting. However, they never attack humans unless you try to manipulate them.
It is said of some people that they have an hourglass figure this very flattering qualifier indicates that their waist is very thin.