Crabronid wasps (Crabronidae)

Scientists suggest that Apoidia, the superfamily classification given to the group of bees and wasps with similar evolutionary paths, started with the predatory wasps. Over time, bees evolved as the nectar feeding Apoidia group.

Apart from a handful of physical similarities with bees, Crabroninae wasp behavior also contrasts with bee behavior. By and large, Crabroninae wasps follow the basic predatory, solitary wasp model. However Crabroninae diversity extends to specialized species adopting other reproductive strategies such as colony building, brood parasitism and close approximation nesting (condo style).

Some entomologists divide the family into six sufamilies based on shared physical and behavioral characteristics. Aphid Wasps, for example, (Subfamily Pemphredoninae) generally share the behavioral characteristic of provisioning nests with aphids.

Bembicinae, the largest subfamily, in terms of total North American species, often go by the name sand wasps, based on their nest building habits.

Most people rightly associate sand wasps with the Crabronid wasps because of their extensive presence in North American residential areas and gardens.

Flies rank at the top of the preferred foods list for most predatory Bembicinae species.

Bembix, one sand wasp genus, often adopt a condo style, close association nest building strategy. Large numbers of individuals often build nests in close association to each other.

Large, closely associated nest building projects also opens up potential space and choices for the many brood parasitic Bembicinae species.

The top picture shows an above average sized species with a black abdomen and white eyes. The bottom of the abdomen shows a white stripe pattern. Other species are more easily recognized by stripes on the top of the abdomen, along with green eyes.

The large tongue and markings of the wasp in the second picture are characteristic of another sand wasp species in the Steniolia genus.

Green eyes and overall body shape look similar in both sand wasp species.

Philanthinae another subfamily with a considerable number of species and wide range, choose a variety of insects for nest provision.

The name beewolves explains the common name for Philanthinae species in the genus Philanthus. Neither bees nor wolves, Beewolves tend to nectar on flowers, waiting to capture a nearby bee for nest provisioning.

The brown eyes and brown body help identify Cerceris bicornuta, a Southeast species. Adult beetles serve as their larval hosts.

Knowing the common name of a third Philanthinae genus, Ant Queen Kidnapping Wasps, provides an adequate starting point for guessing their preferred larval hosts.

Square-headed wasps, (Crabroninae), the remaining subfamily with a substantial North American species presence, measure less than 1/2 inch in length. These relatively smaller wasps tend to capture local flies as larval hosts.

Yellow tends to be the dominant abdominal color. A top down picture highlights the characteristic square head.

© 2009-2011 Patricia A. Michaels