In honor of the local paper’s attempt to get an in-depth look at events around Lawrence for 24 hours, I spent a little time outside city limits with a bug net and a camera. While a bug-on-the-street interview is less traditional than other coverage the day generated, I think that a look at the activities of our tiniest residents is as important.
Below the fold: Craneflies, spiders, snakes, beetles and dragonflies comment on May 10 in Lawrence. Dialup users, beware!, there are copious photographs. Nature lovers, rejoice!, there are copious photographs.
I took a walk through an oldfield owned by the University of Kansas. While I had a killing jar with me, I only used it to contain and photograph my interviewees.
The first and most abundant species of animal I encountered was this cranefly (family Tipulidae). Many members of the family do not eat as adults, and live only long enough to mate and lay eggs. Dozens of them were sitting on leaves of grass, moving just far enough to avoid the disturbance I caused as I walked among them. They wanted to emphasize that they do not bite. The larvae consume roots in some areas, the adults drink nectar if they eat at all.
The tiny bulb below the wing is a structure called a haltere. Like all members of the fly family, craneflies have one pair of wings for flying. Like all insects, they have two pairs of wings, the second of which has been reduced to the small nub you can see there. Halteres are believed to help balance flies in flight.
This cranefly commented that the weather was lovely, perfect for a brief life filled with mating.
My next encounter was with a click beetle (family Elateridae). Like all beetles, the elaterids have front wings which have been thickened and hardened into a protective covering. These modified wings are called elytra. Perhaps thanks to that additional protection, beetles are the most diverse family of animals. When all the beetle species are described, there will be millions. We’ve already got names for 350,000 of them, compared to only a few thousand mammal species. This astounding diversity led one famous biologist to quip that the deity must posses an “inordinate fondness for beetles,” a fondness shared by many entomologists.
Click beetles have a further modified anatomy which allows them to produce a loud click by snapping a spike from one body segment against a hook on the next segment. That click can distract a predator. The springlike force required to produce the click can also toss the beetle out of harm’s way. There are about 7,000 described species of click beetles.
This particular beetle declined to be interviewed, attempting to turn away from the camera, but wasn’t so media-averse as to click its way to freedom.
Further down my path I encountered this spider. It appeared to have caught a small gnat in its web, but like a pedophile caught by an exploitative television news program, fled when the cameras got too close.
While some people are afraid of spiders, they shouldn’t be. Very few spiders are capable of hurting a human, and all spiders kill insects around the house or in the field. This spider constructed a lovely web between a few blades of grass, and its racing stripes definitely seemed to make it go faster.
My final interview was with this dragonfly (order Odonata, suborder Anisoptera, probably of family Aeshnidae). It and several other members of the same species were buzzing across the field, hunting for their prey. Dragonflies are very fast and very maneuverable, and use that mobility to evade people like me and to catch other insects. This one rested on a stem of grass long enough for me to catch it and put it in the jar for an interview.
Insects do not breathe through their mouths the way vertebrates do. Their circulatory system couldn’t transport oxygen from lungs throughout the body, so insects have tiny holes in their side, and open spaces for air to diffuse through, bringing oxygen throughout their bodies more directly. To help that process along, this dragonfly was expanding and contracting its tail, pushing air in and out and helping to circulate the insect version of blood, called hemolymph. While something like the beetle above has a low metabolism and doesn’t have to worry about air circulation, dragonflies have to produce a lot of energy to fly the way they do. This one was breathing hard to maintain all of that activity, and I didn’t keep it in the jar too long so it wouldn’t have to wait for its next meal.
Dragonflies do not sting. A lot of people think that the long tail is some sort of stinger, but it isn’t. They are completely harmless, and do a lot to control insect populations. Their juvenile forms live in the water and eat lots and lots of mosquito larvae. Dragonfly nymphs are also known to eat small fish and tadpoles.
During the earth’s Carboniferous era – 300 million years ago – before insects had evolved the joints need to fold their wings back, let alone developed the halteres and elytra we discussed above, dragonflies and related species dominated the earth. Some fossil dragonflies had wings as wide as 2 and a half feet. Other dragonflies of that era look very similar to the ones we see today. The basic anatomy of a dragonfly makes it a powerful and successful predator, necessitating relatively few changes over the years.
The snake I promised above the fold actually wasn’t seen on May 10, but on April 14. I startled it as I was walking along the side of a pond in the Fitch Natural History Reservation. It slid out into the water to hide. Copperheads (Agkistrodon contortrix) like this are poisonous, though people I know who’ve gotten bitten claim it isn’t so bad. Henry Fitch, after whom the area is named, has studied these and other snakes in the area for decades, and says that when a copperhead bites him, the thing to do is go watch a movie until the venom runs its course. I’m not sure I plan to put that to the test, and I wouldn’t suggest that you do so either. As Wikipedia says, “A bite from any venomous snake should be taken very seriously and immediate medical attention sought.”
The genus name – Agkistrodon – is formed from the Greek words for “fishhook” and “tooth,” a good enough description of the hollow fangs used to deliver the venom. The venom breaks down proteins, causing tissue damage, but are not targeted nerve toxins like some snakes produce.
The family of snakes to which the copperhead belongs is characterized by heat-sensitive organs on the sides of the heat. They can successfully target and strike targets warmer than the background even when deprived of all other senses.
This sensitivity to heat explains why copperheads are such. great hunters of small rodents, with about 90% of their diet coming from mice and voles. That makes them no friend to mammalogists, but vital to ecology and to anyone who doesn’t want to be overrun by mice.
This snake declined to be interviewed on the grounds that it was busy hunting. Given those fishhook teeth, I decided to respect its wishes.
That’s what was happening outdoors in Lawrence on May 10. Be sure to write up your adventures of the day for the Journal-World’s 24 Hours in Lawrence.