For the past few years, I’ve had the privilege to join the students in the UW entomology lab on their annual observation and collection trip to the Colockum Wildlife Reserve. I like to think that I’ve been able to share some of my enthusiasm about pollination ecology, but (of course) I learn a great deal more than I teach.
The photographic opportunities are not half bad, either. This week’s bug is Papilio rupulus, the Western Tiger Swallowtail, taken on my first visit to Colockum Ridge.
Stop the presses: the Bug of the Week is actually a bug!
More specifically, it’s a water strider, in the family Gerridae. If I had to guess, it’s in the genus Aquarius, but I don’t know water striders all that well. (Since the absolute best that I can hope for is ID to genus, I can’t help thinking that I should have written “Generically, it might be Aquarius…” but that doesn’t really convey what I want it to. The English language is a crazy, crazy beast.)
The most distinctive feature of the Gerridae is their ability to move across the surface of a body of water. They’re very lightweight, and they’ve evolved the ability to spread their weight across such a wide area of water that they are completely supported by its surface tension. Like all bugs (Hemiptera), their mouthparts are adapted for piercing and drinking, so if you think of a water strider as a self-propelled drinking straw that walks on water, you’ve got the gist of it.
As usual, though, there are enough interesting things going on to warrant a closer look.
On to the Bug of the Week.
One of these days, I'll actually post one of the Hemiptera (that is, a bug) as the Bug of the Week, just to prove that I know what one is. Today, I'm going to demonstrate my embrace of the vernacular by adding a couple of legs.
Which came first, the flower or the bee?
Despite the setup, that is not a trick question. It has an answer, and as is often the case where insects are concerned, the answer is best expressed with a beetle. Or, in this case, two beetles.
When I first started studying pollination, I assumed that I would just be studying bees. For the most part, that’s how it worked out, but I also assumed that there would only be bees to study. That turned out to be wrong.
Sure, I knew about the odd moth-pollinated orchid or bat-pollinated cactus, and I knew that the adults of many insect species live on nectar, and so provide opportunities for incidental pollination. Still, I thought that the only real pollen specialists – that is, species that can digest pollen, that have specific adaptations for carrying and living with pollen, that show up for pollen even if the flower doesn’t have any nectar – are bees.
Then I saw this thing.
This week’s bug is a stroppy little beast I ran into on a hike outside of Wenatchee last May. I’ve heard these referred to as bombardier beetles, but they’re not: all the two have in common is the attitude, and the ability to make potential predators who approach from behind wish they had done something else.
For obvious reasons, I talk about bumblebees a lot. For rather distressing reasons, the conversation often turns to the mysteries of jet-setting parasites and intercontinental gene flow. Sometimes it seems like these are forces that operate in the background, either by agricultural mistake or in somebody’s unscreened ballast water, but this week’s bugs (yes, beetles) are reminders that species invasion can take place right out in the open.
Last week, I went for a bug with looks. This week, I’m going for drama.
A couple of years ago, I spent a day on the south slope of the Columbia River Gorge looking for native solitary bees. It was the first week of April, which is still a chilly time for bees, but I thought I might find some early risers.
After several hours, I had found absolutely nothing except a couple of ants in a glacier lily and one, lonely blow fly in a buttercup. It was a good day for wildflowers, although it would have been a better day for the wildflowers themselves if there had been pollinators around.
Then, in a patch of Columbia desert parsley, I found this guy.