Backyardsafari's Blog

Environmental Inspiration in Your Own Backyard

Insect Mystery July 31, 2010

As those who follow me on  Twitter may know, I recently moved in to a new apartment. My old apartment balcony was made of concrete and metal, but this new one has a wooden railing.

On the first day I got the keys for the new place and went exploring, I noticed little piles of saw dust underneath some of the rails outside.

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Previous experience (having a wooden deck as a child growing up) told me that the dust was the result of carpenter bees “drilling” into the wooden rails. Not too much of a mystery there!  The mystery comes, instead, from the insect that I then saw flying around the railings.

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It was hard to get a picture of, and unfortunately this is about the best I have.  Is this a carpenter bee? In this case, previous life experience would tell me no!  All of the carpenter bees I have seen look like pretty much like other bees. For example, here is a picture from a pest control site showing what a carpenter bee looks like vs. a honey bee. There is a bit of a size and shape difference, but the coloring is very similar!

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The insect I saw, however, was all black. A google image search reveals that some carpenter bees are black, but according to the Pennsylvania State University Entomology department, there is only one species of carpenter bee in Pennsylvania–Xylocopa virginica. This species is one of the kinds with the stereotypical yellow and black “bee” markings.

There is one more strange thing about the insect I saw.  That head shape!  Again, I wish I got a better picture, but in the image above you can see that the head is much narrower than the body, which doesn’t seem to be the case in carpenter bees.

So what say you, readers?  Any ideas what this mystery insect might be? Do you think it is a carpenter bee after all? I should add that, while I saw it flying around the area with the wood shavings, it never went in any of the drilled holes. I searched for insect predators of the carpenter bee, but couldn’t find anything. I should also add that I have never seen this insect again after that first day! Could it just be a different shaped male of the same species? What do you think?

I am going to end with a picture I found on the U.S. Forest Service website during my search that I thought was too amazing not to share. It’s a picture of the smallest bee (Perdita minima) on top of the largest bee (a female carpenter bee)’s head.

Photo Credit: Dr. Stephen L. Buchmann

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Amazing!

So what do you think, nature sleuths? I’m sure we can solve this mystery together! Please leave any guesses or information in the comments! I would love to know what it was!

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Purple Beetle Catchers July 14, 2010

* Edited to include more information*.

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Have you seen me?

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Recently, while driving around the state of Pennsylvania, I started noticing these purple boxes, high up in trees spaced out along major highways. I saw them on the way to Philadelphia, Virginia, New York, and along roads in the small rural area where I work.

Every time I saw one I wondered what it was for. My theory was that they were part of a scientific study collecting some insect to get an idea of how many were in an area. Having completed research projects myself before, this seemed to make sense–the purple boxes were spaced out fairly evenly, as if to get a solid data set, and were put along major roads I assumed because of their accessibility. I didn’t know what insect they were trying to capture/count, but with their size and height in the trees it made sense that it would be one of our six-legged flying friends.

I always meant to look up the answer but kept forgetting, as so often happens in life. Finally, on a recent bus ride, I saw a box out my window and decided to end the mystery once and for all. Thanks to the joys of 3G and my phone data plan, I was able to google search right then and there. I couldn’t find anything at first, but after trying a few different search terms before typed in “purple beetle catchers along roads” and viola! An article from a Vermont newspaper came up that explained that these purple ‘boxes’ are being used to trap the emerald ash borer beetle.

The beetle turns out to be an invasive species introduced from Asia to Michigan in 2002. It has since spread to at least 12 states and a few Canadian provinces, including Pennsylvania, New York, and Virginia. The adult beetles eat the leaves while the larva destroy the inner bark, which ruins a tree’s ability to move nutrients around. It seems this beetle has killed many millions of trees since 2002, and scientists are trying to find ways to eradicate it.

I contacted a colleague of mine at the Pennsylvania Department of Conservation and Natural Resources to find out more information. He says that usually these traps contain a pheromone inside that attracts the insect, but in this case they actually contain oil from the Manuka tree, which has compounds similar to what ash trees release when they are stressed out (which in this case is because they are being eaten by the beetles). He added that the purple color is also an attractant in this beetle family, which is why the color was chosen. The traps are not supposed to eradicate the beetle, but are helping to find out where the beetle is and monitor its movements. It seems the biggest concern is spreading the borers around through fire wood. If people cut wood infested with the borers and then take the wood somewhere else, a new area can become infested. Many thanks to Jeff at PA DCNR for the information!

This post isn’t just about the emerald ash borer, or the purple traps, though. It is about trying to ask questions about the world around us and then follow through with the answers, even though we are busy and it is hard to remember. I always find it interesting to compare the differences between adult and childhood education.  As kids, we are taught many things. When we ask why, we are told that we might need it later, or that it is part of becoming a well-rounded person. When we grow up, though, this stops. Once you get out of college, especially, continuing education either stops completely or becomes pinpointed to a very specific topic that compliments our jobs and careers. Why? Do we assume that we now are well-rounded people and don’t need to learn anything else? Do we stop becoming curious about the world around us?

I thought consciously about this for the first time in 2005, when I was keeping a notebook during field work in Wyoming. For the first time I took the usual questions that often flit in and out of our heads–I wonder what that insect is? What is the name of this? Why is this happening?–and actually wrote them down and tried to find the answers later.

It can be difficult to remember to do this, but it is a great exercise and one that enriches and compliments our usual daily routines. When I finally picked the right set of search words to find out about the emerald ash borer, I was so excited–and as funny as it sounds, proud–about finally solving this mystery. Because of it, I know more about the world today than I did yesterday.

Imagine–there is a whole drama unfolding in the forests all around us! A stow-away from another land silently devouring trees from the inside out, as teams of scientists try to fight them in an ongoing country-wide arms-race between the beetle’s adaptations and our own human technologies.

And to think I knew nothing about it!

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Have you seen one of these traps near your house or in your travels? If so leave a comment or send an e-mail to askbackyardsafari@gmail.com–I would love to know how wide-spread these are!

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Insects in Your Backyard May 14, 2010

Phew! Long time no post! I apologize for the delay–I have begun a series of days where I take children from kindergarten through 8th grade out to experience nature. I take one grade at a time and show them things on their school grounds and/or take them to a local nature area, like part of a creek or a tree nursery. It has been a busy few days, especially because the rain called for some impromptu in-door lessons to replace what we would have done outside. They have been a lot of fun, and I hope to write more about them sometime soon. For now, though, I want to write about something I saw on my first day out with a class early this week.

A few days ago I took a kindergarten class out to explore the school grounds and see what adventures we could find. We did an “environmental scavenger hunt,” where I told them different things to do, like find a seed, or discover if all of the yellow flowers in the yard were the same, and then they searched for answers. At one point I sent them to look for insects, and one of the students called me over to point out a leaf that had been chewed on and eaten. How clever! I was very excited that this child understood that even if he didn’t see the insect itself, he knew an insect had been there because of the holes in the leaf where it had eaten! That is exactly the type of thinking we need to foster, and could all benefit from!

We talked in the Doorways to Nature post about picking a certain thing to look for on walks (or any time we leave the house) to give a little more variety to our day and try to expand our horizons. On a recent walk I decided to look for insect ‘damage’ to see how much of it I could find. Insect damage is the term used for any kind of insect signs usually found on a leaf. It can be one of the different types of insect feeding, a place an insect has laid eggs on the leaf, or a place where an insect has changed the leaf to make a shelter.

Here is a leaf I found that had hole feeding. True to its name, hole feeding is just when an insect has eaten a hole through a leaf! It can be fairly circular, like this one, or have more irregular edges. See the lighter edges around the hole?  This is where the plant has begun to heal around the place the insect ate. This is very important, so remember it for a little farther down in the post!

Here is some more hole feeding, along with margin feeding, which is when an insect feeds along the edge of a leaf.  There is also some kind of growth on the plant–I am not sure if it is related to the insects or not, and will have to do some more research on that.

Until about 5 years ago I never really thought about insect damage. Then I helped a graduate student one summer with her research looking at insect damage preserved on fossilized leaves. We spent the summer digging up leaf fossils in the Bighorn Basin of Wyoming, and then searching the fossil for signs of insect feeding. The fact that not only a delicate leaf but also the signs of something living on the leaf could be preserved for so long–the leaves we were looking at had lived and died ~55 million years ago–really amazed me, and forever changed the way I look at leaves and insect feeding.

Remember the ring around the hole feeding where the plant is healing that I mentioned earlier? That ring is very well-preserved in the fossils, and is a great sign of insect damage. Here is a picture of one of the leaves we found that summer that was later used on the cover of Science:

[Photo taken by Scott Wing, Smithsonian Institution]

The dark ring around the holes in this fossil leaf are how we know the hole is from insects feeding when the plant was still alive, and not holes made afterwards from decay or damage to the fossil.

One of my favorite types of insect feeding, and one that–believe it or not–is also preserved in fossil leaves is called skeletonization.

It was difficult to get a close up of this without picking the leaf off the tree, but notice the lighter areas around the edges of the plant? This is where all of the layers of the leaf except the veins were chewed away.

When I was in Wyoming for that summer in 2005 I found a living tree that had almost all of the different kinds of insect damage on it that we were finding in the fossils. I pulled leaves off that represented each one and used packing tape to preserve them in my field journal. They have held up remarkably well so far, and the example of skeletonization is especially clear:

There are other types of insect damage as well. The list could go on and on, but the other kind that I enjoy finding the most is mines, where an egg is laid inside the leaf and an insect chews its way out, leaving its droppings behind.  I didn’t find any on my recent walk, but here is a photo example from this wikipedia page:

Searching for insect damage is a great way to learn more about the habitat around you. Are there a lot of insects feeding? Or just a few? Is there only one kind, or are there many? Take a look at the trees and bushes next to where you park your car, or by the building where you work–it could be anywhere, and you don’t have to go on long walks to find it! Let’s see what we can learn about the great drama of Life going on around us by searching for the marks that are left behind.

As always, please feel free to send me photos of anything you find! I would love to learn more about what is around you, and what adventures you have had!