Sphecidae

Sphecidae is a paraphyletic family of wasps, commonly known as digger wasps or thread-waisted wasps. They are part of the superfamily Apoidea, which also includes bees and other related wasp families. Historically a large and diverse group, the classification of Sphecidae has undergone significant revision in recent decades, primarily due to phylogenetic studies using molecular data.

The key characteristic of wasps formerly classified within Sphecidae is their predatory behavior. Adult female sphecid wasps provision their nests with paralyzed insect prey, typically Orthoptera (grasshoppers and crickets), but also other insect orders depending on the specific species. The wasp paralyzes its prey with a sting and then carries it back to a nest, which is usually a burrow dug in the ground, although some species nest in pre-existing cavities or construct mud nests. Once in the nest, the wasp lays an egg on the prey item. The wasp larva hatches and consumes the paralyzed prey as its food source.

The paraphyletic nature of Sphecidae arises from the fact that the family as traditionally defined does not include all descendants of its most recent common ancestor. Modern phylogenetic analysis has revealed that certain groups formerly placed within Sphecidae are more closely related to bees (Apidae) than they are to other sphecid wasps. Consequently, a number of subfamilies have been moved into other families, such as Crabronidae. This reclassification reflects a more accurate understanding of the evolutionary relationships within Apoidea.

The remaining lineages generally recognized that once belonged to Sphecidae (although placements may still be under revision) include Ammophila, Sceliphron, and Sphex genera. These wasps are generally solitary, with each female constructing and provisioning her own nests. They play an important role in regulating insect populations and contribute to the ecosystem as predators.