Tuesday, September 27, 2011

Autumn Insects

Autumn is harvest time, a busy time for wildlife, a time to hoard food or fatten up for the winter. Many insect species don't attain maturity until the fall, and must find a mate and breed in the limited time available to them before first hard frost.

Sad to say, time is running out for this beautiful Common Buckeye (Junonia coenia). According to my Peterson Field Guide to Eastern Butterflies this insect is a "migrant and temporary colonist north to ... s. Ontario". Although Common Buckeyes theoretically colonize this area and even a bit farther north, this is my first encounter with this butterfly and I've never seen one even in larval form or as roadkill. Nor will it be around much longer: this species cannot survive our winters, and new generations from warm southern climes will have to resettle the harsher northern limits of their range all over again next spring and summer.

An inspiring insect, and all those appealing colors and patterns on the wings call for a hand drawn sketch.

Several species of darners (Anax junius and Aeshna sp.) and meadowhawks (Sympetrum sp.) are well known late season fliers. A bit of a wanderer and thereby less often seen is the Black Saddlebags (Tramea lacerata). But it was somewhat surprising to find this female – a teneral – as late as September 26th.

Sometimes Black Saddlebags aren't around for a year or two. But there seems to have been a bumper crop this year, and I've already encountered two others: one on September 16th at the intersection of Louisa St. and the Eastern Ontario Trail, the other on September 19th near the intersection of Alexander St. and the Eastern Ontario Trail.

Always look twice at twigs, bird droppings and dead leaves ... or even living leaves, that green "leaf" could be a Texas Bush Katydid (Scudderia texensis).

A closeup shot of the katydid's ovipositor.

This Maple Spanworm Moth (Ennomos magnaria) is doing its best to masquerade as a dead yellow leaf ...

... while a caterpillar (as yet unidentified) imitates a dry, unpalatable twig.

When an insect advertises its presence with bold colors it's for a good reason! This odd looking "carpenter ant" was was on the run when I took its picture so the image quality is rather poor. Luckily I was unable to capture it to take a closeup shot of it sitting in my hand because it can sting – it's not a carpenter ant, it's a wasp called a Velvet Ant. Timulla sp., possibly grotei, and this one is a female; males velvet ants can fly but the females lack wings. I don't know what kind of a punch Timulla can pack, but it has relatives nicknamed "cow killers" ...

Learn more about the life cycle of Velvet Ants at Wikipedia: Mutillidae.

Easily mistaken for a yellowjacket, the chalcid wasp Leucospis affinis is a parasite of Megachilid bees. Note how this female carries her ovipositor over the top of her abdomen. Another distinguishing characteristic (unfortunately not very clear in the photos) are the enlarged spiny femora on the hind legs.