insects

Broccoli lovers

We were treated to a surprisingly mild day today – around 20°C (68°F), which is beautiful for this time of year. It would have been nicer if it were sunny rather than overcast, but in late October in Ontario you really can’t be picky. I took Raven for a walk (despite that we stayed on our 30 acres, I wore my orange vest just to be on the safe side as I’d heard gunshots from the neighbour’s property earlier in the afternoon) and then bedded down the strawberries before returning indoors.

I never got around to harvesting the last of the broccoli this season. It was my first year growing broccoli, and I kept waiting for it to get a bit bigger, but before it got bigger it would undergo a growth spurt and start flowering. I got a few heads, but the last couple I missed. When they started flowering I decided just to leave them; maybe I could get some seeds off them when they were done.

I noticed, while I was in the garden tending the strawberries, that the plants are still flowering merrily away. Aside from the odd clover here and the stray aster there, they’re pretty much the only thing in the landscape that still is. This fact hasn’t gone unnoticed. The warm weather this afternoon had some late-season pollinators out looking for flowers to forage on, and they’d all converged on this small patch of yellow blossoms. I’d left my camera up at the house while I took the straw down to the garden, and couldn’t resist going back for it to document some of what was crawling over the plants.

There were three bumblebees (three!) visiting the broccoli flowers. At first I thought this one was Tricolored Bumble Bee (Bombus ternarius), by default due to the orange, though there are actually a few species that sport the orange bands on the abdomen. The most common in the east is Tricolored, but we also have B. sylvicola (no common name) and Red-belted Bumble Bee (B. rufocinctus).

I spent a while puzzling over the photos on BugGuide.net, trying to decide what the differences were between the species, before getting frustrated and Googling a North American bumblebee identification page. I discovered this great ID page, which is found at Bumblebee.org. It seems to have originally begun as a UK site – if you Google “bumblebee guide”, most of the first couple of pages are UK sites, and I get the impression they’re much more into their bumblebees there than we are here.

In any case, that fabulous ID key (now bookmarked!) pointed me to Red-belted Bumble Bee, primarily due to the orange butting up against the black on the abdomen – the other species all have a yellow band between them.

Bumblebee species #2 is, I’m fairly certain, a Common Eastern Bumble Bee (Bombus impatiens). This species appears to fly quite late into the fall, with BugGuide having records as late as November for Ontario. It’s also very common, and not at all picky in its habitat or food plant selection. Anywhere and everywhere will do for these guys.

I don’t know about this one. It looks different from #2 – the blacks look blacker, the spot on the thorax larger, a wider band of yellow on the abdomen – but it could simply be individual variation. Or, it could be a male Red-belted, which show no red belt (just black). I think I’m leaning toward Common Eastern, however… it seems like it has a black head, whereas Red-belted would be yellow, I think.

The only other bee visiting the broccoli flowers was this little green sweat bee. There are three genera, all with shiny green representatives, and all looking fairly similar. This individual might be Augochlora… or then again, it might be Augochlorella or Augochloropsis…

This one looks like a bee, but is actually a fly (note the big eyes that touch each other). There are a number of species of flies that are bee or wasp mimics, their disguise providing them with protection against possible predators. Some are incredibly convincing. This one looks to be a member of the genus Eristalis, a group whose larvae are aquatic scavengers.

I was watching another fly when I noticed one of these guys camouflaged against the stem. A green caterpillar, so well hidden it had taken me several minutes before I noticed one. Looking more closely, I ended up spotting half a dozen. There are three species of green caterpillar that might be found on brassicas such as broccoli, but this one, with the thin yellow stripe, will become a Cabbage White butterfly, a very common species.

As I investigated, I spotted one caterpillar who was receiving some special attention from a little fly. It took a bit of hunting, but I believe the double-bulbed abdomen makes this a black scavenger fly, a member of the family Sepsidae, and probably within the genus Sepsis. Google “sepsis fly” and you get quite a number of results of studies looking at copulatory behaviour in the genus… From what I can tell, however, the family are more interested in dead than live material for laying their eggs on/in, and so this guy may not have had any real interest in the caterpillar after all.

Then there was this little wee guy. This one really is a species of ichneumonid wasp, and really is parasite of other insects. There are quite a number of species of ichneumonids, and I’m not precisely sure which this might be. I suspect, however, Hover Fly Parasite (Diplazon laetatorius), based on the black body and red legs with white stripes. It’s a widespread species that parasitizes the larvae of a wide variety of fly species.

These hemipterans weren’t new for me, though I had to look up their names again. Tarnished Plant Bugs (Lygus lineolaris), or perhaps a related species. It’s a fairly widespread species in the east, and adults are active most of the year, into quite late in the fall. Their larvae are generalists, but particularly like agricultural and commercial crops such as soybean and cotton (and, apparently, broccoli).

And the final critter crawling about the flowers was this tiny moth. It’s a Diamond-back Moth (Plutella xylostella), an introduced species that was probably accidentally imported in the mid-1800s. Caterpillars feed on plants in the family Cruciferae which – you guessed it – includes broccoli. Unsurprisingly, adults occur wherever these crop plants are grown (pretty much everywhere), and have a very long flight season.

Four days early

Another beautifully mild day today, with our thermometer peaking at 17 oC (63 oF) in the sun mid-afternoon (actual temperature was somewhat lower, but not by a great deal). We’ve had a string of such nice days now. It looks like after tomorrow a cold front will move in and drop temperatures down for a few days, but by this time next week we’ll be back up again. I’ve been starved for balmy, sunny weather, I’ve been soaking it in these last few days.

So has the wildlife. I’m up to 12 species of moths recorded so far this season already. This seems to me like an extraordinary number for March 17, and I’m not sure how much of that number has to do with the string of warm days (perhaps we didn’t run into that last year?), versus me actually setting up and looking for them (I didn’t try this early last year because I didn’t want to waste my time if nothing was flying, since it was more of an effort when we were in the apartment, but this year since we’re in a house I can put the light out anyway and it’s not a big deal if nothing comes), versus simply being in a great place for moths (and everything else; I love my home).

Last night I got two moths which I took photos of this morning, after holding them chilled in the fridge overnight. Rather than just setting them up on the deck railing or on a sheet of paper or something, I hunted down a dead leaf that was still in good shape as a photo base. Most were starting to fall apart, or if they were still intact, they were curled up. Finally I found one that was whole, and mostly flat. When I picked it up and turned it over, I noticed a small white speck on the underside. It turned out to be a leafhopper. I think it’s a Red-banded Leafhopper, Graphocephala coccinea, also sometimes known as a Candy-striped Leafhopper. It’s very pale, and I suspect this may be because it had just recently emerged, and its exoskeleton was still soft (the colours in insects’ exoskeletons often strengthen as the shell hardens).

Also something I noticed today that I hadn’t over the weekend was a profusion of flies. They were ubiquitous in open areas where leaf detritus had piled up in the fall, such as the edge of our driveway and lawn, or the clearings along the forest edge. I’m not positive on its ID. I think it might be a Stable Fly, Stomoxys calcitrans, which is a common and cosmopolitan species. I was able to rule out House Fly by the veination on the wings, but that was about as far as I got. Flies are a group I’m content to leave to someone else’s expertise.

Edit: Kirk suggests in the comments that this is a Flesh Fly, family Sarcophagidae. So not even close to Stable Fly. I told you fly ID is better left to the experts.

I was intrigued by the discovery of the leafhopper, and the presence of all the flies, and thought perhaps during my walk with Raven today I’d take my camera and see what other spring insects I might be able to turn up. I wasn’t expecting much – after all, it’s only March 17 and there’s still snow on the ground in many places. But I might be lucky and find one or two.

I was surprised to discover a total of 13 individuals of 7 species today. Leafhopper and flies were #1 and 2, but species #3 was the above – fire-less fireflies known as the Winter Firefly, Ellychnia corrusca. The genus Ellychnia are all diurnal, and as such lack the light-emitting organs of most other fireflies (not much point, they wouldn’t be seen). They are also most commonly found on tree trunks, and indeed these two (plus one other) were climbing up the ridged bark of a big White Pine. The Winter Firefly, presumably taking its common name from its cool-weather tolerance and early spring appearance, also happens to be the largest firefly of the northeast by almost twice as much – the large one in this photo was probably about 18mm, perhaps 5/8″.

A couple trees away, sitting on the side of a hop-hornbeam, was this critter – a ladybeetle, but not the generic orange-with-black-and-white-“head” Asian Ladybeetle that we’re so used to seeing around the house and garden. This one is actually native, and discovering native ladybeetles is such a rare occurrence for me I could count the total number I’ve seen on two hands. Surprisingly, there are actually more than 480 species in North America, so I don’t know how much of my not having seen many is simply because they’re secretive compared to the Asian invaders, or because the Asian beetles are outcompeting them. This particular one, seeming the reverse in pattern from the usual black-spots-on-red, is called the Twice-stabbed Ladybeetle, Chilocorus stigma. You can see why the species was named such, but it’s a slightly morbid name, particularly when you consider the Lady in ladybeetle was actually a reference to the Virgin Mary.

There has been a general decline in ladybeetles on the continent, and in recognition of this the Lost Ladybug Project was started in an effort to build a database of ladybeetle sightings to try to help with monitoring these species (since it’s really hard for a couple of Cornell scientists to cover the entire continent). If you have any ladybeetle observations be sure to send them in!

I just happened to spot this guy sitting still in amongst the leaf litter while I was photographing a fly, not a foot away. It is a true bug with the scientific name Menecles insertus, and was easy enough to pick out in the Kaufman Insect guide by its all-brown colouring and pale stripe down its back. It seems to be a fairly common insect of the east, feeding on a range of deciduous trees. My guess would be that its brown colouring is an adaptation to a late fall and early spring adult stage, since the predominant colour in the landscape at those times of year is the brown of dead leaves. There wasn’t much info available in either resource I checked, though, and I’m simply hypothesizing that it overwinters as an adult since that would make such an early spring appearance easier.

I found two of these spiders, in two different spots. I think they’re a type of wolf spider, but I don’t have a definitive ID on them yet, either. They were scuttling through the leaf litter, and, aside from the flies, were the main source of eye-catching movement that I encountered. All of the rest of the insects required examining the ground more closely.

I also don’t know what this beetle is. It was just a wee little thing, less than half a cm (less than 1/4″) long, but a bright iridescent bronze. I had happened to kneel down to inspect a large rock with mica deposits in it, and as I was checking out the mica, a little beetle comes wandering up over the top of the rock in front of me, like he wanted to make sure he was counted.

Edit: In the comments, Ted makes this suggestion: “The beetle is a leaf beetle (Chrysomelidae) in the genus Graphops (subfamily Eumolpinae). It could be G. curtipennis, a common eastern North American representative, although there are a number of species in the genus that are difficult to sight ID.”

One other species I saw but didn’t post here was a diurnal moth, a small little tan guy, whose identity also remains unknown to me. It’s amazing how much time one can spend trying to identify things if one really wants to.

Finally, species #13, was these grasshopper nymphs (above and below). I found the green one first, and was quite surprised to discover a grasshopper. I didn’t notice until I got home that it was a nymph and not an adult. Part of the presence of grasshoppers so early is explained by this. It turns out they’re both Northern Green-striped Grasshoppers, Chortophaga viridifasciata. The species has two colour morphs, with both sexes occurring in both colours, but with females predominantly green and males mostly brown. Eggs are laid and hatch in the summer and over the course of the fall the baby ‘hoppers go through a few moults. The winter arrives while they’re still nymphs, though they may be anywhere from half-grown to nearly adults. They overwinter as nymphs and emerge early in the spring to finish growing. They’re usually the first species of grasshopper to be encountered as adults in the spring because they’ve got such a huge head start on development over other species that overwinter as eggs.

Total counts to date this season: 12 species of moth, 12 species of other insect. At March 17th! And spring (the official first day) not even here yet, it’s still four days away. I just can’t get over that. It looks like we’ll have to endure a few chilly days as a cold front moves through later this week and into the weekend, but we’ll be back up to these temperatures again next week. I wonder if I should wait till the 21st to declare spring finally arrived?

The hundred-legged one

What is it about invertebrates that creeps people out so much? Cockroaches are the stereotype of unclean dwellings, and used dramatically to draw shivers from an audience, but really the insects probably have little to no interest in you personally. A spider crawling out of a drainpipe can prevent someone from stepping into a bathtub (no way was I climing in until it was taken outside or flushed down again), but the chances of it crawling on you, much less biting you, are pretty slim.

My personal insect-phobia, the one that will cause me to throw a garment into the air shrieking should I discover one hiding inside a seam, is earwigs. Creep. Me. Out. I’m not sure why, although perhaps it goes back to my childhood and having earwigs occasionally climb into clothing while it was drying on the line outside (I should note I was never bitten by one, but that didn’t reduce their creepiness). They particularly favoured the lining of bathing suits, for some reason. I’m also not terribly fond of silverfish, though that doesn’t have any childhood encounters tied to it. The rest of the groups I’m generally okay with, although spiders are better if they’re at a distance.

One guy I know revealed that he’s creeped out by leeches. Another guy said his was house centipedes, which was also my sister’s when I asked her. A couple days ago we had one of these show up in our bathroom sink (the photos in this post are of this obliging individual). I have to admit they’re fairly creepy crawlies, as creepy-crawlies go. Up to two inches long, with giant long legs that spread out in a large oval shape, long antennae and rear legs, and they can dash across a wall at lightning speed. They’ve never really bothered me, but perhaps that’s because I have all of my energy invested in earwigs.

Centipedes, unsurprisingly, get their name from their many legs (cent = hundred, pedes = feet). Millipedes also take their name from their many feet, but the “milli” means thousand. You can tell the difference between centipedes and millipedes because the former are usually flattened with just one pair of legs per body segment, while millipedes are rounded and have two pairs of legs per body segment. Millipedes have a defence mechanism of curling up into a spiral when threatened, while centipedes, which don’t have the same strong upperside, instead run away (and I challenge you to try catching one!).

There are a number of different species of centipedes in North America, but the house centipede (Scutigera coleoptrata) is the only one from the order Scutigeromorpha (the group is also called house centipedes; since the North American species is the only one on the continent, it can get away with using the group name as the species’ common name). It’s actually not even native to North America, but was instead originally from the Mediterranean and has since spread (hitching rides with humans or their cargo). It can now be found here as well as in Europe and Asia, and a few spots in Africa, Australia and New Zealand. In Japan, they’re reasonably popular and Wikipedia suggests it can often be found for sale in pet shops.

Millipedes are scavengers, eating detritus and dead material. Centipedes, including the house centipede, are predators, eating insects and arthropods commonly found in a household environment, such as spiders, ants, silverfish, cockroaches, termites and bedbugs, and as such could be considered beneficial bugs to have around. They kill their prey by injecting venom through small “fangs”, the same way spiders do. Although it is technically possible to be bitten by a house centipede, you would have to be intentionally or accidentally handling it, and even then it probably wouldn’t feel like much, as their fangs are too small to puncture most skin. The biggest house centipedes might be able to inflict a good bite if presented some soft skin, which would feel a bit like being stung by a bee, and would similarly subside after a few hours (also, a small number of people may be allergic to the centipede’s venom like some people are to bee stings).

Although they can be found almost anywhere in the house, they prefer damp locations, such as basements or bathrooms, or overwatered houseplants. Outside they can be encountered under rocks, in wood piles or in compost heaps. They’ll happily overwinter in your house, and are commonly seen in spring (or in mild spells mid-winter) when the weather begins to warm.

House centipedes start out with just four pairs of legs when they hatch, but go through a series of larval stages (“instars”) where they shed their previous exoskeleton (their hard outer shell – insects wear their skeleton on the outside and attach all their muscles to its inner surface, compared to vertebrate animals whose skeleton is inside with the muscles affixed to the outside). It may take them up to three years to reach full size, where they’ll have 15 pairs of legs (centipedes can have anywhere from 15 to 100+ pairs of legs, but the number of legs is always odd). Once full grown they can live up to seven years.

Adults have compound eyes, like many insects (though we tend to think of flies first), and so have excellent vision (also helpful, in addition to their speed, in evading capture). They’re the only group of centipedes to have this feature. They have three modified feeding appendages, “toothed” mandibles (visible in the above photo as a sort of beak-like shape under the face), a pair of maxillae, and a pair of leg-like palps (visible in the previous photo as . The mandibles “chew” the prey while the other two appendages manipulate it. The “fangs” are found on the first body segment, behind the head. I kind of think it looks like a grasshopper head, and if you couldn’t see the rest of the body you might almost believe it was related to this much less creepy crawlie group.

Sleepover guests

My parents live in a 100-odd year old farmhouse out in the country west of Toronto. Sharing the building with wildlife was part of growing up, whether it was bugs or vertebrates. We had mice in the walls (occasionally seen scurrying across the kitchen floor), starlings in the eaves, snakes and newts in the unfinished basement, squirrels and bats in the attic. Most of our houseguests were primarily active during the spring and summer months. In the winter, our primary visitors were, and are, ladybugs.

Anyone in an older home is probably familiar with the mid-winter ladybug invasions that seem to coincide with warm spells. Within the space of a few days, the house seems to become overrun with them. They gather in the corners of window frames, congregate around light fixtures, and seem to find their way into or onto just about everything – hair, clothing… food… Just where do all these bugs come from, in the middle of winter when insect life, as a whole, is pretty absent?

Growing up I used to think that the warm spell encouraged a hatch of ladybug eggs that had been laid in the fall before the first frosts. Actually, all of these uninvited guests are adults, that crawled under the siding or into the cracks of the house in the fall to overwinter. In the warm spell, they awaken and start to move around, and the warmer temperatures indoors draw them inside through small cracks in the walls or around the windows. I know that in my parents’ 100-year-old farmhouse, the insulation is not quite up to modern-day standards, and there are ample opportunities for a little beetle to squeeze in to the much more habitable warmth of the indoors.

The ladybug most people are familiar with is the Multicolored Asian Lady Beetle, an extremely variable ladybug that comes in a wide range of colours and spottiness. Above you can see two very different colour variations of the same species. It’s also the primary culprit in winter home invasions. The species was introduced in Louisiana and Mississippi in 1979 and 1980, as a method of controlling aphids and other agricultural and horticultural pests. They’ve spread a long way since then! You can actually buy ladybugs commercially from garden centres or online to release in your garden as a natural pest-control method.

Ladybugs in and of themselves are essentially harmless, although they can be a bit of a nuisance during their winter invasions. Once the temperature drops following the warm spell, ladybugs that have come into your home will congregate in corners where they will resume their hibernation. During the winter they live off stored fat reserves, but the dry air in most homes during the winter can cause dehydration in these little bugs that results in piles of dead bodies. Ladybugs that manage to make it into enclosed light fixtures usually can’t make it out again and collect in the bottom.

Aside from this, the ladybugs leave little stains that, growing up, I took to be “ladybug poop” in the corners where they congregate. In actuality, these stains are the result of the ladybugs being startled, threatened or stressed. As a defense mechanism, ladybugs have the ability to excrete some of their “blood”, which has a bright yellow colour and rather sharp, and not altogether pleasant, smell, which discourages potential predators. In prepping the windowframes of my parents’ house for repainting this winter I could easily tell where the ladybugs had been.

I was rather surprised that our recent warm spell didn’t cause the sort of mass invasion I tend to expect with higher temperatures, and while I came across little groups of ones or twos in most corners of the house, there weren’t the large groups I associate with mid-winter warming. Something yet to look forward to, I guess!