The Marvelous in Nature

A potato surprise

A few weeks ago I was preparing dinner and pulled out and peeled a few potatoes for whatever meal I was making. Three were just fine, but when I cut open the fourth it was dark and decayed all down the centre. I was surprised; there’d been a small blemish at one end, but there are often small blemishes and I just cut them off and use the rest of the potato as normal. But this one was hollowed out.

As I was contemplating whether it was worth cutting out the decayed bits and using whatever was left, or if the smell/taste of the decay might have permeated the whole potato, I saw what I thought was a bit of movement. Tiny, thin slivers of silvery-white, no wider than two or three hairs. I thought they were hairs at first, until they started crawling.

So I did what anyone who found their grocery-store potato infested with tiny silver worms would do: I put the potato slices in a bowl, covered the top with cling wrap, poked a couple of holes in it, and brought it up to my study for observation.

I wasn’t sure what to expect. I was kind of thinking they might be fruit flies, because that seemed the most logical choice for an insect that’s snuck home in fresh produce. But I figured if I just exercised a bit of patience, hopefully I would see. If they were in fact fruit flies, I’d have less than two weeks to wait – which is how long it takes a fruit fly to go from egg to adult stage.

I kept checking on it. After a couple of days I realized the potato was starting to dry out, so I started spritzing it once a day with water to try to keep it moist (not too much; I didn’t want them to drown). It would’ve been better if I hadn’t peeled the potato, but at the time I was peeling it I didn’t realize it held a secret inside.

Five days later, when I peered closely I noticed what seemed like a lot of tiny pearl-white seeds congregated in one spot within the decay. This was exciting! I figured they were nymphs, or the next life stage of whatever it was that the potato was growing. I got my camera and macro lens and got the closest shot I could of them.

This is the image, cropped to 100% – as close as I could get. I’ve been having some trouble with my camera card reader on my computer – it works, but takes some patient fiddling with – so I didn’t check them out closely right away. On the back of the camera, though, they kind of looked like tiny beetles, like maybe a nymph stage. I knew that beetles have a worm-like grub stage, and I’d already observed worm-like grubs, so that’s what I figured they were. Beetles. Just needed to wait till they grew into adults to find out what type.

I waited some more. Another few days went by. Finally, one afternoon I peered in to the bowl and there it was! The adult!

It wasn’t a beetle.

It was, in fact, a gnat of some sort. (Beetles, I learned upon further research, don’t have a nymph stage; their larval instars all look roughly the same. Ditto for gnats. More on this later.) Unfortunately, it accidentally got squished before I could get a photo, and only two adults ever emerged from the potato halves; I wondered if I hadn’t been keeping it damp enough in the decaying sections. So I don’t have a photo and can’t definitively say what it was. But it looked something like this:

This happens to be a fungus gnat that drowned itself in my tea a couple of years ago.

My beloved Kaufman Guide to Insects doesn’t have much on gnats, so I turned to Google, which knows everything. Fungus gnats can be a real nuisance problem with indoor houseplants, and nearly everything Google turned up pertained to using a raw potato slice, placed on the soil surface, to draw the fungus gnats out of hiding so they can be removed. From this I deduced that they must actually use potatoes as hosts, at least occasionally.

I had to dig a little deeper but I did finally find a page in amongst the household remedy hits that confirmed this. This University of Florida information page said:

Most species of darkwinged fungus gnats (Sciaridae) feed on fungi and decaying organic matter and are not considered economic problems. A few species, however, attack healthy tissue of such economic plants as potatoes, wheat, red clover, alfalfa, cultivated mushrooms, pine seedlings, and various ornamentals, including tulip bulbs, ferns, begonias, coleus, geraniums, cacti, young orchids, areca palm, and dracaenas.

That’s quite the list! But heading it up is potatoes, which was the one I was interested in at the moment. Figure 2 on the page is actually of the worm-like larvae in a decaying potato.

Anyway, back to this photo:

I thought it was a larval stage of the beetle-no-actually-gnat. Until I double-checked the life cycles of beetles and gnats, and neither turned up any reference to a tiny, globular larval stage. That’s weird, I thought. But I image-googled “fungus gnat larva” to be sure. It was all photos of adults or the thin, silvery worms… except there were a couple that were round, slightly-haired critters.

Following the first image brought me to this bug-control page, which was a sales page for a live shipment of the invertebrate Hypoaspis miles. They’re predatory mites, and one of their primary prey items is – you guessed it – fungus gnat larvae. It says they are a soil mite, native, and fairly versatile in terms of habitat/substrate. Was that what I had? Predatory mites that ate all my fungus gnat larvae which was why I only got two adult gnats? Unfortunately, I don’t think the photos I took are of good enough quality to know for sure, but that’s the way I’m leaning.

So even though I only got two adults and ended up with more mysteries than answers, I’m considering the potato experiment a success.

Thaw

I think most years about this time, give or take a week, we get a thaw where the weather is gorgeous and mild and the sun is shining and the snow melting and the insects poke their heads out for a breath of fresh air. Today was one of those days; a balmy 5.5°C (42°F), which had me returning from my walk with my jacket unzipped and my mittens stuffed in my pocket (in truth the mittens never came out). Even though I understand the groundhog saw his shadow last week and we’re in for six more weeks of winter, days like today give you hope that spring is not that far off.

(Potentially only three weeks, in fact; last year the first moth of the year came to our door on February 25. Of course, the evidence suggests he was not quite all there (or maybe just hopelessly optimistic), given that it was -3ºC (26ºF) at the time I found him. The first sensible moths showed up last year on March 17, which is – coincidence? – about six weeks from now.)

In any case, as I stepped out today I noticed some insects milling around on the sun-warmed cement and log beams of the house, which were, I believe, the first outdoor insects I’ve seen moving about this year (this doesn’t include springtails, which are probably not insects). Most of them are Small Milkweed Bugs (), which I’ve written about a couple of times before. They’re familiar faces, now, the first brave souls to venture forth at the hint of spring warmth. (In contrast to last year and the year before, I did actually ID them correctly this year; I’ve had a habit of calling them Box Elder Bugs when they first appear.) They’re a few weeks earlier this year; last year they didn’t come out to sunbathe until February 22.

(One of the most interesting things about keeping a blog has been being able to track the phenology of certain events like this, and compare it from one year to the next. I’ve always meant to keep a journal of sightings, first and otherwise, and some years I’ve even actually started, but I never remember to keep up with it. Perhaps it’s because, come April and definitely May, one starts to get flooded by all the “first” observations. I should probably select a few favourite and harbinger species – Red-winged Blackbird, American Woodcock, Dutchman’s Breeches, Coltsfoot, first moth, first butterfly, first Small Milkweed Bug – and just remember to record those every year. After all, they’re the ones that please me so when they first appear.)

The milkweed bugs were joined by a few other critters – a couple of species of fly and a single spider, none of which I feel confident in ID’ing. I didn’t even bother trying for a photo of the spider as he was tucked into an awkward spot on the wall. Below is one of the flies. By the time I got back from my walk the sun had slipped farther down the sky and the patch of wall they’d all been hanging out in was now hidden in shadow; all but a few hardy (or hopeful?) milkweed bugs had retreated back to their cozy niches. We’re back to a forecasted high of -7°C (19.5°F) tomorrow, so that might be it for another few weeks, but it was a nice treat for early February.

Flying Squirrel

I missed last week’s post, busy preparing for a wedding, and yesterday, catching up from the wedding; apologies! But I’m super excited about today’s post. I was planning on another topic for this evening, actually – I’ll end up doing it this weekend, perhaps. But as I came down to check on the fire I noticed Oliver was hunched over, peering out the window at something at the window feeder. He does this regularly, and always when I go over to look there’s nothing there.

But this time there was! A small, furry brown body was curled up right at the window’s edge, its back to the house. I thought at first it was a rat or mouse, but then it stretched out to grab a seed and I got a good look at its eyes. They were huge! This was no rat – it was a flying squirrel!

I knew we had flying squirrels around here because I’d found shredded cedar bark in one of the nestboxes a couple of years ago. The box actually wasn’t that far from the house, but I’d never seen evidence of them visiting the feeders (on the other hand, I don’t know exactly what I’d be looking for). I have, however, on occasion heard little feet scampering up the side of our log house while I’ve been working in my study late at night. I know that sound from the daylight hours when the Red Squirrels run up and down to the feeder. I guessed that the nighttime scamperings must therefore belong to flying squirrels – but I’d never seen one till tonight. Here or otherwise.

There are only the two species of flying squirrel in North America (though there are a few subspecies). Ours are most likely Northern Flying Squirrels, though we’re near the northern edge for Southern Flying Squirrel, too. There are visual differences between the two species if you get a good look at one, including size, but they’re most readily distinguished by habitat preference, with the Northern preferring mixed or coniferous forests and the Southern largely mature hardwood forests, especially Carolinian. Our forests around here are pretty strongly mixed.

The flap of skin between the front and back legs can only be easily viewed when the squirrel is gliding, of course, though you can sometimes see the wrinkle there when they’re still. They’ve also got flattened tails that presumably help with steering when they’re in the air, and oversized eyes to help see in the dark. They’ve got a varied diet and are pretty opportunistic about what they eat, but Wikipedia suggests the bulk of their diet is truffles (various types of underground fungi), which they sniff out with their nose.

Obviously, they also eat birdseed. We have our feeder set up so one side of it is butted up against the house, below the living room window. The cats and Jack love this. Jack’s mostly interested in the Red Squirrels, while the cats prefer the birds. The critters at the feeder learn pretty quickly that what’s going on behind the glass has nothing to do with them and they’re free to keep eating. All of our animals will paw at the window or press their faces right up to it, but it doesn’t bother the critters at the feeder in the least.

Apparently the flying squirrel has learned this, too. It sat not four inches from Oliver’s nose, just a couple panes of glass between it and some sharp teeth. But it was very confident in those panes of glass. Charlie came and joined us after a bit (the two of them made it a little hard to get any pictures). I could put the camera right up to the window, the lens knocking against the glass and the flash going off at regular intervals, and the squirrel would be completely undisturbed. It’s too bad there’s a screen in the window; it makes it hard to get good shots. The smeary nose prints all over the glass doesn’t help, either. ;)

I hope he’s a regular visitor! I think it’s so cool we’ve got a flying squirrel coming to our feeders.

Waxwing droppings

When Dan came inside a couple of days ago he told me, “There’s a blog post for you over by the shed. All over the snow.” Figuring there’d been a predation out there and I’d had a murder scene to dissect, I grabbed my camera and went out to investigate.

But instead of finding fur or feathers, I found… purple stains?

It didn’t take much detective work to guess what these were from. We’ve had a flock of waxwings hanging about the last week or so. I’d thought they were Bohemians, the first time I noticed them, but I had no binoculars and the year since I’d last seen Bohemians had left my ear a little rusty. They turned out to be Cedar Waxwings the next time I saw them. (In my defense, Bohemians are much more common around here in the deep winter than Cedars are.)

The stains, of course, are the waxwings’ droppings, dyed purple by the berries they’d been eating. There aren’t a lot of purple berries available at this time of year; wild grapes and buckthorn would be the primary candidates. At the centre of most of the stains was either a bit of berry skin or some seeds, so I took a closer look to try to determine what they were eating.

It doesn’t help that wild grapes and buckthorn berries are both roughly the same size, especially after having passed through a digestive system. I took a photo of the bits, with my fingers for scale, figuring I’d try to look them up.

I first tried googling buckthorn berry seeds to see if I could find any images to confirm that’s what this was – I know what domesticated grape seeds look like, but don’t know if the wild type look the same, and I’ve never opened up a buckthorn berry. When that turned up nothing, I thought, you know, the easiest way to confirm this would be just to go get a buckthorn berry and see.

I write most of my blog posts in the evenings or, often, late at night. So this thought occurred to me at about 11:30 pm. After some minutes of weighing it in my mind, I finally decided that yes, in the interest of completeness, I’d venture out and find a buckthorn berry. Just to be sure.

I bundled up, grabbed a flashlight, and called to Raven. (Perhaps strangely for someone whose primary interest is a nocturnal taxon, I’m somewhat afraid of the dark. Fortunately, all the snow in the winter means it never gets really dark at night.) We ventured out to the one location on the property where I knew there were some buckthorn. The shrub was mostly empty, but a few lone berries remained.

Upon returning to the house with one, after stripping off all my winter garb again, I broke it apart on a kitchen plate. Inside the thin skin were four blunt-ended teardrop-shaped seeds that looked exactly like the ones in the droppings. Combined with the fact that the buckthorn shrub had been cleaned out, I’m pretty confident in saying that that’s what the birds have been eating.

Edit: Super-smart bird-poop expert Julie Craves comments that these are probably, in fact, wild grapes. D’oh! Check out her explanation in the comments for why.

I blogged about buckthorn a little over a year ago, and commented on its potential benefits to wildlife. It’s kind of nice to see our local wildlife making use of an invasive plant like this, especially since it’s one of those species that’s been so successful there’s probably little hope of eradicating it anymore.

Rough Stink Bug

With the onset of winter it’s been a little while since Dan brought me any interesting nature discoveries, but a couple of days ago he walked into my study and set something down on my desk. It clicked as it landed lightly on the wooden surface. “Two of these have been flying around my lights all morning,” he said. Bugs seem to like Dan; I rarely have anything flying around my lights. The odd ladybug, perhaps.

In this case the pestering creature was a stink bug. Sometimes also called shield bugs for their medieval-shield shape, they have the distinctive (and memorable) ability to produce foul-smelling secretions when threatened or disturbed. The idea is that the smell will put off potential predators; since most birds have a very poor sense of smell, presumably the secretion also tastes bad. If you catch a stink bug in a bad mood, you’ll soon know it. Fortunately, this one seemed to be pretty calm.

Using my Kaufman Field Guide to Insects I narrowed the genus of this individual down to Brochymena (rough stink bugs, I think so-called for the toothed edges to the pronotum, the section right behind the head), and then went onto BugGuide to figure out the species. I’m pretty sure this is a Four-humped Stink Bug, B. quadripustulata (“four pustules”?), which is one of the more common and widespread members of this genus. The KGI indicates that adults of some Brochymena species hibernate as adults beneath bark, so I’m wondering if these two came in with the firewood.

I found it interesting how much red the bug had on it, when I looked at the photos. To my naked eye it seemed fairly uniformly brown, with some darker Vs at the shoulders and around the bottom of the scutellum (the bit in the middle of the back that appears as a pale U in the first photo, and which didn’t stand out as pale to my eye). It amazes me how much detail cameras reveal in these smaller subjects, and it’s one of the reasons I enjoy photographing moths and other insects so much. (Incidentally, the random little pale dashes, such as the one on his head, are moth scales. I had him in one of my moth jars until I got my camera equipment set up.)

Although some of the 250 species in family Pentatomidae are hunters of other arthropods, most feed on the sap of plants. Some can be serious crop pests. They stab the plant with their long, thin proboscis and use it like a straw to suck the sap out. This doesn’t usually kill the plant (except in cases of bad infestations) but because a scar will form where the plant was pierced it can create deformities and blemishes – a problem for farmers trying to sell their produce for human consumption since we humans are so picky about the aesthetics of our produce. Sometimes it will destroy seeds, which can be problematic for grain crops or things like corn, where the seed needs to be whole to be useful. When not in use, the proboscis is tucked firmly against their underside. You can see it here as a thin line going from the head down between the legs.

The other interesting thing you can see on its underside is the scent gland that produces the stink. It’s just a small divot in the side of the thorax, dorsal to the middle leg (ordinarily, when the bug is upright, it would be right above the leg, but in this photo it’s right below). A close-up of the gland is below, indicated with an arrow. Not the best quality, but he was squirming a lot, rowing his legs and pushing against the stone to try to flip himself upright. He wasn’t having a lot of success, and as soon as I got the photo I turned him over again. (For a better-quality photo, check out this one on BugGuide.)