Sunday, August 29, 2010
Sorry, More Bugs
Sorry, more bugs. I told myself not everyone is as fascinated with bugs as I am, but then I found a really interesting one, one that nightmares are made of.
Dale (my husband, and Eleanor (our friend) were on our way to photograph dragonflies at one of our favorite spots, Lake in the Woods. It occurs to me a lot of our good sightings this summer are by-products of our search for dragonflies: The otter eating newts, the butterfly that lays down a chasiity belt, the hummingbird stealing sap from a sapsucker, etc. We learned a long time ago to grab serendipitous events. It’s good to have a goal in mind, but there should be a lot of flex built in. In this instance we had already entered the Umpqua Nation Forest and were bumping along on the last stretch – seven miles of gravel road. About a mile from our goal a very narrow gravel road branches off at an odd angle, leaving a sunny triangle of grasses and weeds in the middle of the forest. We spotted a dragonfly in the opening and all piled out.
The sunny opening is buzzing with insects. I quickly verify three species of dragonflies: a common green darner zooms overhead while a variegated meadowhawk and an autumn meadowhawk perch on the tips of tall grasses. Dale finds a spider to photograph. The spider has wrapped up an ant and is sucking its juices. Suddenly a pine white butterfly gets tangled in the web too. A robber fly grabs a honey bee and lands on Eleanor’s shirt. She patiently stands still while we photograph. At least four species of butterflies are busy in this tiny opening. So much going on.
And then a great big lump flies past me and lands on the tip of a large grass. It must be a fly. Flies have only one set of wings, whereas most flying insects have two pairs. Their second set of wings is reduced to funny stubs called halters. But I’ve never seen a fly like this. It reminds me of a miniaturized dirigible. Blunt head. Blunt rear end. Huge eyes. It’s about ¾ inch long and looks heavier than any fly I’ve ever seen. It lands for about a minute, then zooms off for two or three minutes. My triangle of grass is small enough I can spot it wherever it come back to rest.
When we get home I dive into Kaufman’s, “Field Guide to Insects of North America.” It’s a bot fly! There are 41 species of bot flies in the United States. Only two are shown in Kaufman, but mine is similar to one whose larva are parasites of small mammals. Bot flies can’t bite. They can’t even eat, but their life history is a little unnerving. The female lays about 2000 eggs. She picks spots where they should come in contact with the host species –in a rabbit nest, a mouse tunnel, grasses where rodents forage. The egg is heat sensitive and hatches when a host is near. The tiny larva usually enter through the mouth or nose, but an open wound will do. It soon travels to a subcutaneous location and spends the next month or so living off the host before emerging. After emerging it drops to the ground to pupate.
My friend, Donna, somehow got a bot fly larva into her body when she was traveling in a foreign country. Of course she didn’t know it at the time, but pretty soon she realized she had a funny little lump on her hand. The lump got bigger and bigger. One night it was time for the larva to emerge. Out he poked. I’m pretty gutsy, but I know I would have been a little unnerved by seeing that bot fly larva crawl out. For my fly to be so big, the larva has got to be big too.