bugs – Page 6 – Seabrooke Leckie

Rubus galls

I have been seeing these things around our property since moving here. Initially there were just a handful of them, in the Rubus canes along the edge of the woods. I took a photo last winter, the first time I found one. I came home, tried to ID it, couldn’t find anything that quite matched. I found another this fall. Took a photo, came home, tried to ID it, came up blank. A few weeks ago I came across another, same thing. Each time I was sure that I just hadn’t been using the right search term, or looking in the right place, or something like that.

Then earlier this week I found a whole patch of them, in a thicket of canes over at the 100-acre woods. There had to be more than a dozen, clustered into just a few square meters. “Okay,” I told myself, “I really need to get these figured out.” I ran off a bunch more photos then came home, made myself a tea, and forced myself sit down and look till I had an answer. Worse came to worst, I figured, I’d post it to BugGuide and hope Charley Eiseman would help me out on this one, too. ;) But it’s so much more satisfying (and you remember better) if you can identify it yourself.

I think what had been causing me problems is I’d been looking for a photo match. This has always done me fairly well before. Go to Google image search and type in some sort of descriptive term, and in all likelihood someone else has described and ID’d the same thing you have. This didn’t work in this case. It pulled up quite a number of lumpy galls, but none of them looked to be the same as mine. I also tried my favourite recent reference acquisition, Eiseman & Charney’s Tracks & Sign of Insects (go get a copy, if you haven’t already! You’ll thank me!), but none of the photos there looked like my thing, either (though some looked similar). I repeated this process in each ID attempt, and again this week.

It was only on this most recent try that I finally delved into Eiseman & Charney’s text, paying close attention. And it was in there that I think I found my answer. I found three references to galls in brambles (Rubus sp.).

The first stated, “Metallic wood-boring beetles (Buprestidae) include the red-necked cane borer (Agrilus ruficollis), responsible for slight, ridged swellings that are 1 inch (2.5 cm) long in bramble canes”. Which, as cool as it would be for my galls to be wood-boring beetles, didn’t seem to be it. They’re more lumpy and large than slight and ridged, and most are longer than just an inch.

Number two said, “Woody stems and twigs are host to a number of Neolasioptera midges … N. nodulosa [is responsible for] swellings on brambles, sometimes ridged and usually near the tip of the stem.” This seemed a definite possibility. None of them were ridged, but the text only said “sometimes”. Many (though not all) of mine were near the tip. So I Googled it. They definitely do make swellings on bramble canes, but they seem to be much slimmer than what I have. Hm. Back to the book.

The final reference read, “Several species of Diastrophus (Cynipidae) cause pronounced swellings on blackberry stems (as well as roots), up to 6 inches (15.2 cm) long.” I’m not sure which species of Rubus is referred to by “blackberry” (there are at least two that could be called such), but they’re the right plant genus, anyway. And these galls are definitely pronounced, and a couple of them did reach a few inches long. The BugGuide.net page for D. nebulosus looks pretty similar, and the text did suggest that there are several species, which may or may not necessarily all look the same.

So I think these are Diastrophus galls. The insects that made them are wasps. They look less like what we typically think of as wasps, and more like fruit flies – very squat in stature. The lumpiness of the gall is due to the presence of many chambers within. Presumably the adult female lays many eggs into the plant, all clustered together, and they all make their own swelling, which in turns creates one large, lumpy gall. There doesn’t seem to be very much out there on their life history, but from the circumstantial evidence of my observations it would seem they overwinter in their galls and emerge in the spring to mate.

Though the galls on our 30 acres were untouched, more than half of the ones at the 100-acre woods had been investigated by birds. Downy Woodpeckers and chickadees will both drill into galls to extract the grubs overwintering within. They’re most commonly known to do this with goldenrod galls, but obviously these Rubus galls were large enough and promising enough to draw their attention. Where the birds have chipped away the woody cover, you can see the dark holes belonging to each individual chamber. (And it was the discovery of this, more than the abundance of them, that made me really want to get an ID after finding the bramble patch.)

Pre-Easter egg hunt

I love a good scavenger hunt. I love the challenge of hunting for something particular, given some guidelines on where to look, and the delight and satisfaction when the target is found. Which is probably why, every winter, I go out one afternoon to see if I can figure out where the tent caterpillars are going to be this year.

It all started when I found a cluster of white eggs on the shiny dark bark of what I think was a young apple tree, in spring of 2008. It had always seemed to me that the white tents of the tent caterpillars appeared as if by magic in the spring. One month there was nothing, the next month there was this large, fist-sized webbing in the fork of a branch. So when I discovered that the moths lay their eggs on the branches – fairly conspicuously, I might add – and that they spend the winter in this state… well. A challenge, if I ever saw one.

That was 2008. Late in the winter of 08/09, I went out and scoured the branches of appropriate trees, deliberately trying to find the egg masses of the tent caterpillars before they hatched out in the spring and started building their webs, and was pleased to actually find some. I did it again last winter, too, though I only mentioned it in passing in another post.

And here’s this year’s cohort. The top photo is of last year’s eggs (laid 2009, hatched 2010). The second photo is of what will become this year’s caterpillars (laid 2010, will hatch 2011). Between laying and hatching, the eggs are covered by a shiny brown, hard shellac-like cover that helps to protect them from the elements and potential predators. When the caterpillars hatch in the spring, they’ll have to chew their way through this cover to get out. The shellacking falls away after this, leaving white eggs with dark holes in the tops – how you can tell the difference between old and new eggs.

After they hatch, the caterpillars move down the branch (toward the trunk) until they reach the first major fork. There, they set up shop and start building their web. This photo is of a clump of new eggs only a handspan above a major fork. I bet you can guess where the nest is going to be, come May.

Tent caterpillars are no more than an aesthetic nuisance – they very rarely cause any lasting damage to the tree – and so I leave them. Out here in our fields, there’s no one to be bothered by a defoliated tree anyway. Once the caterpillars move on to pupate, in late spring/early summer, the tree will have a chance to regroup and fix itself up again before it has to go dormant for winter.

I talked a bit more about tent caterpillar biology in my original post from 2008 (mostly post-hatching info).

Sunday Snapshots: Log pile

A couple of days ago we had a (relatively) mild, rain-free afternoon and Dan decided it would be a good opportunity to try to move another load of wood from the piles out in the field into our basement, where it’s easy to access two or three times a day (the woodstove being our only source of heat, we burn a fair bit).

The wood in the field was here when we moved in, and our landlord gave us the freedom to use it as we needed it. I’m not sure what the full story is on it, but it’s obviously been stacked there for years – and years and years maybe – because the stuff that was well-covered is incredibly dry, and the stuff that wasn’t as well protected is, in some cases, starting to go a little punky.

Prior to moving it in, Dan had to sort through the pile to separate the dry stuff from the punky and/or wet stuff, and halfway through he came back to the house and called up the stairs: “Seabrooke? Are you looking for blog material?”

I’m always looking for blog material, and of course he knows that. I grabbed my camera and joined him out at the wood pile while he finished sorting out the logs. Hidden amongst them were numerous critters and other interesting things. I decided to make this a Sunday Snapshots because I wouldn’t be able to ID the spiders or beetles, and with a Sunday Snapshots I wouldn’t have to… ;)

Burr oak acorns — The log pile sits under a Bur Oak; many of the burry caps had collected in the gaps.

A white-bellied spider in a silk cocoon, alongside a dead pillbug/sowbug.

caterpillar? — A caterpillar... I think?

Gypsy Moth pupal shells - a male hatched out of the one on the left, a female out of the one on the right, as determined by size.

11-0867 - Agonopterix pulvipennella - Featherduster Agonopterix — 0867 - Agonopterix pulvipennella - Featherduster Agonopterix

Woolly Bear and Gypsy Moth pupal case — Woolly Bear and female Gypsy Moth pupal case

0889 - Two-dotted Agonopterix - Agonopterix argillacea and 07-0639 - Caloptilia stigmatella - Poplar Caloptilia — 0639 - Caloptilia stigmatella - Poplar Caloptilia (left) and 0889 - Two-dotted Agonopterix - Agonopterix argillacea

holes by boring beetle/insect — All of the sawdust that one moth is buried in came out of these tiny holes, created by some type of wood-boring insect and/or its larvae.

scale insects — some type of (dead) scale insect

More Christmas bugs

I hope everyone had a Merry Christmas, if you celebrate it, or a happy holiday season if you don’t. I returned to my mom and dad’s for our family get-together. It’s one of the few times of the year where all three of us daughters get a chance to visit together and with our parents, and we all look forward to it and generally have a really good time. I’m always happy to be returning back to my own house and bed and fur-family, but it’s still sad for the visit to be over.

On Christmas day we had a couple of other visitors join us for a bit. The first one I noticed was the Boxelder Bug above. He was strolling along the windowsill, listening in on our conversation, though he didn’t have much to add to it. Boxelder Bugs, like ladybugs (such as the one below, who was the other visitor eavesdropping on our discussion), are common winter houseguests. They spend the winter as adults, and search for a cozy nook to hole up in over the cold months. This often ends up being cracks in your house’s exterior walls, and sometimes they can make their way all the way inside. Though I’ve seen the species before, this is the first time I’d actually spotted one indoors.

In some areas they can be so common as to be a nuisance, but I’ve never seen such aggregations. The most I’ve personally observed in one place was at my sister’s new house this autumn, where she had a dozen or two crawling about her front porch. Fortunately, they’re pretty harmless. They don’t bite or sting, and unlike ladybugs, they won’t poop on and stain your window frames. Since it was much too cold to put him outside, we let him be. It was Christmas, after all.

Fir galls

Continuing with the theme of the left-behind… I do a lot of peering at branches in the winter months, after most life has gone into hiding. Sometimes some interesting discoveries can be made, affixed to (or even within) twigs or branches. I took Raven down to the 100-acre Woods yesterday, the first time we’ve gone in a little while because of hunting season (we’re in the mid-November hunting lull at the moment, but we wore our brightly-coloured jackets, just to be safe; I don’t think anyone hunts on that bit of land, but who knows what goes on there when no one’s around to see it). The forest has a fair bit of Balsam Fir scattered through the damper areas, and I paused at one clump to finger the needles, whereupon I noticed these odd little lumps amidst the foliage. There were a lot of them, mostly at the outer ends of the branches, and mostly (it seemed) on the east side of the tree (though that might just be coincidence).

Determining their identity was fairly easy once home. A Google image search for “balsam fir needle galls” turned up several pages with identical galls to mine. Gotta love the forestry industry’s thoroughness; virtually anything you want to know about pests of commercially valuable tree species is available online. The pest in question here is a tiny midge, Paradiplosis tumifex, which goes by the appropriate English name Balsam Gall Midge.

Eggs are laid on current-year needles as they’re growing (which explains why the galls seemed mostly to be near the ends of branches), and when the egg hatches the larvae burrow into the needle to settle down and feed. The needle forms a gall around the larva and its new home. The larva eats and grows and eats and grows, until mid-autumn when they finally break loose of their gall and drop to the ground. There, they burrow into the soil under the tree and wait for spring. Warming ground temperatures in late April and early May encourage the larvae to pupate, and a week or two later the tiny adults begin to emerge. Females mate, then return to the newly-forming fir needles where they lay their eggs, and the cycle begins again.

Once the larvae leave the needles in the fall, the needles brown and drop from the tree. The branches were scattered with the ones that had caught in the twigs. I noticed on the ones that were still attached to the branch that a few of them seem to be broken off; I’m not sure if this was from the midge larva emerging, or environmental damage post-emergence. The midges are no more than a nuisance, apparently; they do no long-term damage to the tree, beyond perhaps mildly stunted growth that year when under severe outbreak conditions. The galls are dropped by the winter, and even aesthetically the tree looks fine again quickly (important for the Christmas Tree market). Populations are cyclical, with two or three years of high numbers, followed by several of low. I can’t remember having noticed anything unusual about this same tree last year (it grows beside the path), and I’m not sure if that’s because numbers were low last year and high this year, or I just wasn’t looking.