I am a high school science teacher, National Geographic Grosvenor's Fellow and a nature columnist. This blog highlights nature columns that appear weekly in local seacoast New England Newspapers
"The best thing one can do when it is raining is to let it rain" - Longfellow
by Sue Pike
July 25 2017 The York Weekly/Portsmouth Herald/Foster's Daily and online at seacoastonline.com .....etc
What better summer pastime than sitting by a pond on a hot day? The frogs are languidly croaking, and the mosquitoes are not so terrible at the moment so just a few are buzzing by your ear. The surface of the water is a still and clear as glass, the surface broken only by the occasional minnow rising or a water strider skimming over the surface, tiny dimples where its feet touch the water.
As a biology teacher, I love the water strider. Whenever the topic of water and why it is vital for life on Earth comes up, we talk about the amazing properties of water, one of which is that water molecules are sticky. Water molecules like to stick to other water molecules to the exclusion of other molecules, air for example. So, when you have an air-water interface the water molecules will form something akin to a skin (this is called surface tension, and, scientifically, is not a “skin” but looks like one because the water molecules at the surface are sticking so strongly to each other and not to the air it makes it more difficult to break through that surface tension than to move around in the water beneath the surface). Because water has a high surface tension, some organisms, like water striders, can walk on it instead of breaking through.
I was watching some water striders on a neighborhood pond and wondering why
Water striders legs characteristic dimples where they touch the water Sue Pike photo
they were one of the few animals cruising around on the surface of the water. Why so few other insects shared their domain. An occasional water spider skittered across (but they aren’t insects) and some groups of springtails congregated in the shadows, but it seemed like everyone else was down in the water, not at the surface. I wondered how difficult it was for a small insect to break through that “skin” on the surface of the water. Would it be like punching through a brick wall or like tearing gossamer veil? (I can’t answer this yet, but still wonder — I only know that if a water strider is pushed beneath the surface it can drown).
There are quite a few species of water strider found in North America. As members of the class Insecta water striders have three pairs of legs. The front legs are much shorter than the back two sets of legs. The short front legs are used to catch prey - they eat any kind of aquatic insect or larvae they can find (mosquitoes and dragonflies are typical prey). The back two sets of legs are used to walk on the water. They are very specifically designed for this - attached to the thorax in a way that is optimal for water striding but doesn’t work at all for walking on land.
Not all insects can walk on water; water striders can because they have very fine hairs on the undersides of their legs that trap air and repel water (the scientific term for this is superhydrophobic). There is an incredible video on the American Association for the Advancement of Science website (www.sciencemag.org/news/2014/03/secret-walking-water) that shows what researchers have learned about how water striders seem to move so effortlessly on a pond’s surface: “By vigorously rowing along the surface, striders create swirls that help propel them forward, all without rupturing the water surface.” I highly recommend watching this - you will look at water striders with an entirely new appreciation. They are incredibly fast - they can move at the speed of a hundred body lengths per second, this is like a six-foot tall person running at 400 miles per hour.
Watching water striders can be a great way to while away a summer afternoon, but I recommend against trying to pick one up. I’ve read that water striders don’t bite humans, but know from experience (my kids picking them up, not me) that they can inflict a painful “bite.” (I’ve never actually verified whether this is a real bite or imagined, but the shriek from my son seemed real). They have piercing mouthparts that can pierce their prey’s exoskeleton and suck out the juices. This is what they do to one of their favorite prey, mosquito larvae. They grab the mosquito larvae by its breathing tube when it comes up to breath, pulls it through the surface of the water and sucks it dry... it is always a good thing to have some water striders around.
by Sue Pike
appeared week of August 28 2017 in the York Weekly, Portsmouth Herald, Foster's Daily and more
I was hiking up Mt Moosilauke last weekend. Toward the start, about 20 feet back from the trail, a Chicken of the Woods mushroom beckoned to us. The size of a stop sign, at least a couple pounds in weight, its bright yellow color glowing, it seemed to be asking us to come collect and eat it. We still had many miles to go so we decided to pick it up on the return. Coming back down we looked and looked but couldn’t find it, I think this loss is probably going to haunt me forever. It looked like the most perfect Chicken of the Woods fungi I have ever seen.
While I love the subtlety of nature, I also like things that are easy to identify - blue jays and cardinals, oak and maple trees, and edible mushrooms that cannot be mistaken for anything else. Chicken of the Woods fungi are one such mushroom. If you know a little bit about mushroom anatomy they really are unmistakable.
by Sue Pike
8/19/2017 The York Weekly/Portsmouth Herald/Fosters Daily Democrat and more
Of the many mysterious things you can find while beachcombing, one of the most difficult to understand is (I think) the egg collar of the moon snail. These beautifully-sculpted ribbons of sand show up on our beaches this time of year. A friend recently brought me one - it had washed up above the tide line, dried out and was starting to crumble. I knew it was a moon snail egg case but had to wonder how it was crafted; I certainly couldn’t have made such a thing. The story of how the female moon snail does this is spectacular - a nice example of the myriad of solutions nature has come up with to help with the task of reproduction.
Moon snails are beautiful, round, moon-shaped snails (hence the name) that live just offshore of sandy beaches and on tidal sand and mudflats. They burrow in and through the sand in search of their prey. Pick up a clam or mussel shell, even a moon snail shell, if there is a…
August 1 2017 The York Weekly/Portsmouth Herald/Foster's Daily/seacoastonline.com etc
My neighbor has a beautiful hop hornbeam tree growing next to his driveway. Up until a couple years ago, I had never heard of this tree and spent some time trying to convince him it was an immature shagbark hickory (which it doesn’t resemble at all, so I’m not sure why I firmly believed this to be true). Then for a while I thought it was an elm (which is a closer fit than the shagbark) and finally, I really looked at the tree, saw the “hops” and figured out what it really was.
The hop hornbeam (Ostrya virginiana) is a small tree which is commonly found in the understory of our hardwood forests. They are often described as unremarkable trees (even maligned as weed trees in managed forests). These are completely unfair descriptors. No tree is unremarkable; look close enough and all have their own unique charm. Hop hornbeams are particularly gorgeous trees. Their bark is grayand thin,…