Growing by the Bay

Month: September 2018

Senecio talinoides

After several years in the garden, the plant is starting to flower. Stay tuned.

wasp on sedum flower

Wasp on Sedum

Wasp on Sedum

This wasp, which I believe is Prionyx thomae (P. parkeri and P. canadensis are similar), seemed very interested in a flowering sedum. It appeared to be collecting nectar, though conceivably it was just watching for prey.

Fairly common in the western U.S. and south to Argentina, Prionyx thomae is a solitary wasp. The female kills prey such as grasshoppers by injecting them with venom, then carries the remains back to a nest where it can serve as a host for its offspring. Because the stinger is not barbed like that of a bee, it doesn’t break off in its victim, and the female can inflict multiple stings. (The male lacks a stinger entirely.)

If my insect identification skills were better I might be able to tell if this is a male or a female. Guidelines from Bohart, R.M., Menke, A.S., 1963, A Reclassification of the Sphecinae: With a Revision of the Nearctic Species of the Tribes Sceliphronini and Sphecini:

  • Male—Average length 12 mm; head and thorax black, gaster red, tergites rarely with darker markings; wing clear in cellular area, darker beyond; erect hair of head and thorax white; flagellum as in figure 103; sternite VII entire
  • Female—Average length 13 mm; pronotal lobe and vertex, scutal furrows, mesopleura behind pronotal lobe, and pleura above mid and hind coxae with appressed silvery pubescence; labial palpus generally not visible in museum specimens, much shorter than maxillary palpus

The female carries its prey, sometimes larger than itself, to a chamber it excavates at the end of a tunnel that it digs for the purpose, then lays its egg.

Bug Eric (my best source) describes such a wasp grappling with its grasshopper prey.

Some rights reserved 2020 Tom’s Garden. This work is licensed under a Creative Commons (attribution, noncommercial, no derivs: 3.0) License (US), although some of the work this blog incorporates may be separately licensed. Text and images by Thomas Christensen unless otherwise noted. For print permissions or other inquiries please request via rightreading.com/contact.htm.