Saturday, August 22, 2009

A Leatherwing and Wasps

Update: One insect was originally identified incorrectly. See here for an explanation.

As the season has shifted into late summer and different plants have matured and bloomed, I have been seeing a different set of insects around the garden. Here are a few that I found yesterday.

First up is a Pennsylvania Leatherwing (Chauliognathus pennsylvanicus), a soldier beetle, with its head planted firmly in a flower. The Kaufman guide describes it an autumn insect that is common on "goldenrods and thoroughworts," but in this case it is feeding on a mint plant. Like other soldier beetles, leatherwings rely primarily on nectar but also eat pest insects such as aphids.

As I was taking these photos, I was fascinated by the wasp-like stripes on the leatherwing's abdomen. So far I have not found an explanation for them.

In the photo above, the leatherwing is joined by a wasp, which I believe belongs to the genus Philanthus. Wasps in this genus are known as "beewolves" because they prey on other stinging insects. Female Philanthus wasps dig burrows and lay their eggs on paralyzed bees and wasps.

I have been somewhat surprised by just how popular these mint plants have proven among insects. I have seen many different species nectaring there. In addition to the two mentioned above, I have also seen honey bees, bumble bees, and at least one fly species. Today the mint flowers were full of wasps. Philanthus wasps were probably the most common, but I also saw a couple Eumenes fraternus wasps wasp-like thick-headed flies (see here), and at least one other species I couldn't identify. Members of the Eumenes genus often build mud nests to lay their eggs. Four Three wasps, including two Philanthus wasps, and one Eumenes fraternus (right) are shown in the photo below.

More photos of these insects at my Flickr account.