Our insect of the week for August 5 is not a beetle. Surprise! For the last 3 weeks, we have been discussing beetles. If you start observing animals in central Illinois, on average about 75% of those you observe will be beetles. Yes, they are that common and diverse.
Another very diverse group, often overlooked unless they are bothering you, are members of the order Hymenoptera. Megarhyssa macrurus is our insect of the week this week. It is classified in the family Ichneumonidae. The species name translates from the Greek words makrós (long) and oùrá (tail). What a surprising name – just look at the ovipositor on this female. This species was described by Linnaeus in 1771. Although the ovipositor (tail) looks like a single filament in life, it has been separated into the three filaments (the middle one is the actual ovipositor). This species uses its ovipositor to drill into wood to deposit its egg in the larvae of another wasp – the horntail (we may feature that one at some point in the future). The egg hatches and devours the paralyzed horntail larvae (the Megarhyssa female also stings the larvae deep in the wood to paralyze it before depositing her egg). So, this wasp is actually a parasite of another wasp. There are so many insect stories in central Illinois. We are just introducing you to a few. Have you ever seen this wasp in central Illinois?
Updated November 11, 2024 – If you are curious what the male of this species looks like here is a lateral view (scale is a bit different). This specimen was collected by our former member, Gordon Adams in 1961 in Peoria County.
