Tuesday, March 29, 2016

Fishflies and Dobsonflies


No, this is not a prehistoric monster from a horror film (e.g. Them! or The Beginning of the End). It is an insect in the family Corydalidae. The common names of these insects are Fishflies or Dobsonflies. They are very important insects in healthy aquatic ecosystems. 
Immature corydalids (larvae) live underwater in well oxygenated streams and are also called hellgrammites.
Adult corydalids (pictured here) are very large insects with wing lengths ranging from 2.5 cm (1 inch) to over 5 cm (2 inches) and wingspans of up to 14 cm (5.5 inches). 

The individual in these pictures is probably a fishfly. Fishflies are smaller than dobsonflies, with wings that are usually less than 5 cm long. Adult dobsonflies and fishflies don't actually eat very much (if anything) and they are around for only a few weeks before they die. The larvae however are alive for up to five years, living underwater as predators of other insect larvae. The next time someone tells you that dobsonflies only live for a few weeks you can kindly explain to them that while they only spend a few weeks of their lives as adults, they are alive for up to five years before that.

My friend found this fishfly last May in her yard near Long Lake, MI

Wednesday, February 10, 2016

The Red Headed Menace

Many insects are not what they seem to be.
This (above) is a red-headed ash borer (Coleoptera: Cerambycidae 
Neoclytus acuminatus), but it looks like a paper wasp (below).
The red headed ash borer is not really a menace. Unless you are a recently cut or dead ash tree, they will not harm you. They have evolved to resemble paper wasps and other stinging insects, which protects them from predators. They might be found in homes in late winter or early spring when they are brought in with firewood. My friend found this one last week inside of a local business.