Weekend Expedition 70: Mississauga/Credit River

Mar7

On Sunday, Catherine and I went out to Mississauga, where we met up with Gil Wizen, one of my favourite macrophotographers to go out for a early spring hike around the woods above the Credit River. It was such a treat to be out with a fellow invertebrate zoologist, not having to explain why exactly we should flip over a given log, or pull up a piece of loose bark…How very rarely do we get to go out in the woods with another person with the same agenda!

The forest was snowy, but warming, and we are anticipating a major thaw through the week….Very soon, the famed Ontario salamander fauna will be on the move to vernal pools for breeding. This weekend we did not find any salamanders, but we did find a great variety of cool arthropods, thanks in no small part to diligent searching by Gil.

The wooded bluffs above the Credit River, near the Mississauga campus of U of T was where we wandered. The geology of this place looks pretty fascinating, with some thin layers of sandstone very near the surface, often pushed upward by tree roots.

Catherine and Gil on the way to the forest.

The mixed forest seemed to have abundant birdlife, and it would be good to come by earlier or later in the day to see if we could find some owls…

Many of the birds were doing what we were doing, probing under bark and looking in crevices for invertebrates.

One of our very first finds was also one of the coolest: A Dolomedes tenebrosus, looking fat and happy under some loose bark. This is a species in the fishing spider/nursery web spider family (Pisauridae), and it is usually found near water. They are undoubtedly major beneficiaries of abundant aquatic insect hatches in certain seasons.

Here is the same spider resting on a block of the sandstone cap that we found thrust up near the tree roots. The large eyes of these pisaurids are evident, and hint at relationships with wolf spiders, also in the Lycosoidea clade.

We found a much smaller Dolomedes tenebrosus nearby under some leaves. Interestingly, both of these spiders seemed not strongly affected by the cold, and were able to move about even though it was hovering near zero.

Gil examines a rotted and fallen trunk. I asked him whether he had done this sort of think since childhood, and it seems that like me he has always flipped logs and rocks looking for invertebrates. A born naturalist!

A caterpillar of Idia lubricalis (a hermiine erebid), also found under leaves. Thanks to Gil for the ID!

Like the previous week in Crother’s Woods, we also found a number of crab spiders and running crab spiders. Here is a running crab, likely a Philodromus species.

A small (Handsome Fungus, family Endomychidae) beetle found in fungus-rotted wood. This one has a very pleasingly-shaped pronotum and daintily-clubbed antennae.

Gil also uncovered some tiny psuedoscorpions, which was a treat to see.

Many thanks to Gil, for leading us to a very productive patch of woods. We look forward to getting out again soon!

Weekend Expedition 69: A muddy slog in Crother’s Woods

Feb29

Sunday afternoon was warm and sunny, but when Catherine and I went out to Crother’s Woods, the forest was sodden and mucky. Nonetheless, we set out for a short stroll, looking under bark of fallen trees and in the leaf litter for creatures…

So have a gander at what we found!

We found a bunch of Bassaniana (now Coriarachne) bark crab spiders overwintering in bark crevices. These are extremely cryptic on bark, and are probably very abundant all up a tree.

These bark crab spiders have very robust forelegs, and likely can take relatively large prey.

These bark crab spiders are extremely flat!

This running crab spider (Philodromidae) was also found under bark, along with the Coriarachne.

Yet another philodromid. I wish we knew the species here!

Catherine managed to find a sac spider (Clubionidae, likely genus Clubiona) in a sac, also under bark.

This shot shows the sac spider’s eye arrangement.

Catherine found this eastern yellowjacket queen under some bark as well. She is overwintering, and we took good care to replace her in an equivalent crevice.

She was completely motionless, with wings held in a protective posture typical of overwintering yellowjackets. I was interested to see that her wings tuck under the spines on the hind tibiae.

One of our coolest finds was this minute tree-fungus beetle on a bracket fungus on a birch tree. (family Ciidae, maybe Ceracis thoracicornis? OK, this is not even a ciid at all! Gil Wizen has informed me this is a tenebrionid, Neomida bicornis!)

These beetles tunnel through the tough fungus, and I cannot understand how these forward-facing pronotal spines are helping!

This beetle was less than 2 mm long, and made my day.

If anyone out there knows what they use these spines for, please let us know!

This looks like the larva of a flat bark beetle (Cucujidae) (but wait! It is not! Again, Gil Wizen to the rescue! This is a fire-colored beetle, Neophryochroa femoralis)

A closer crop reveals that the water droplets act as magnifiers, bringing into view structures such as the tracheae, visible through the translucent cuticle (click picture for larger view).

Like most of the under-bark fauna, these beetles are very flat! Even adult cucujids are very dorso-ventrally flattened.

Although much of what we saw was above freezing, wood in contact with the soil was still partially frozen, and these isopods were in the midst of ice. Ice-o-pods. Get it? Anyway, we are due for more freezing weather in Toronto, so I hope you have enjoyed these pics…It is not likely we will get any more this week!

Weekend Expedition 68: A frozen High Park outing

Jan25

Catherine and I were on our way to see a talk on environmental restoration by Dr. Dawn Bazely, York U prof and prolific scientist, author and SciComm advocate, held Sunday at the Howard Park Tennis Club. This talk was not only interesting, but for Catherine and myself it was a great way to get introduced to the High Park Stewards, a local conservation group focused on the large western Toronto park.

Before the talk, we had a couple hours to wander around the frozen landscape, seeing what we could rustle up. It turns out, not much was active on this cold and cloudy Sunday. Perhaps best exemplifying this is the hibernating Carabus (either granulatus or maeander) that we found under a log. These large carabids are a familiar sight in logs in wintertime, but unlike the ones we see in coastal BC, this one was not going anywhere fast!

If only all carabids were so docile!

After wandering up a hill, we stopped by a section of the park where people leave seeds for the birds, and saw what are probably Toronto’s most common winter songbirds, House Sparrows, Cardinals, Black-capped Chickadees, Red-breasted Nuthatches and Downy Woodpeckers vying for the free meal. I concentrated on shooting the woodpeckers, because they were not as shy.

Because it was so dark, I engaged the stabilizer on my 300 for all of these shots. Not too shabby!

Just love the little mustaches on these bold woodpeckers!

Here you can see the specialized foot morphology that woodpeckers have for clinging to vertical surfaces.

Although these were taking seeds from the piles on the ground, they would also peck at various branches nearby for insects.

These lovely birds added a splash of colour to an otherwise gloomy day in the park.

Weekend Expedition 67: the mythical white squirrels of Trinity Bellwoods

Jan18

Catherine and I undertook a short expedition out to Trinity Bellwoods Park to see if we could spot the famous white squirrels which live in the area. These are not a different species, but rather a colour morph of the native Eastern Gray Squirrel Sciurus carolinensis. We did see a white squirrel on the coffee shop outside, along with some white squirrel bling on the inside. Unfortunately, I found the coffee was sour in that particularly obnoxious way that clueless hipsters are so fond of. “Yeah man, I liked coffee before it was good. You wouldn’t understand.”

(BTW, this type of crappy coffee is not limited to Toronto. We found more than our fair share in Vancouver as well. )

We did of course see some black squirrels, another morph that folks further south find quite interesting. These are actually quite common all over Toronto.

The park itself is a bit of an overrun mudpit in the winter, which the dogs seem to enjoy, but makes for treacherous walking.

The squirrels did squirrely things, such as hand face first down treetrunks, and sit in high branches making clucking sounds. These are scatter-hoarding rodents, caching food through the summer in order to survive the winter, but in urban areas make a good living on handouts and raiding gardens.

We saw several wasp nests, free of waspy occupants in the frigid air. Luckily there are lots of tree cavities around for the new queens to overwinter.

The more typically-coloured gray variant of the gray squirrel was in evidence as well, doing some major clucking from perches, as well as seeing of we had any nuts to fork over.

They are quite handsome animals, and one can’t help but marvel at their strength and speed as they navigate the trees. A squirrel must also have a tough heart to endure all the rapid climbs and descents.

The black morph probably gains some thermal advantages that offset the increased predation risk of having such an obvious coat colour.

The most exciting part of this trip was watching the squirrels chase each other, something that will probably happen more frequently in springtime. It did however, lead to my best shot of the day:

Voilà! The flying squirrel! A bit out of focus on the head, but still pretty good for a speeding squirrel!

Serious gull baths

Jan1

Catherine and I went to Beacon Hill Park yesterday, and were delighted to see some gulls having a pre-New Year’s bath in one of the ponds. With the winter sun making good highlights, the shots were a natural choice for pictures. What really strikes me about these bathing gulls is how they seem so serious about their hygiene routine. I suppose with the cold winter weather it helps to have maximum floof potential in your feathers before a long cold winter night.

Some winter spiders at Island View Beach

Dec31

Catherine and I are back in BC for Christmas, hanging out with my mom in Victoria. The weather has largely been atrocious, so the photo opportunities have been scarce. However, the past couple days has seen a bit of clearing, so we headed up to Island View to see what we could see.

A small male Pardosa was the first wolf we saw, and was surprisingly active, despite the freezing temperatures.

A larger female wolf was a bit less active, but still good to see.

Though the weather is cold, prey are still around and active, and in fact the widows we saw still had small capture webs. Not sure if they ever snack on these termites, but it is possible.

Many of the female widows were quiescent, though some could still move about.

As usual, there were immature males hanging out on the periphery of the females’ webs. These “winter males” are bigger, bulkier, and more like females than the summer crop.

It is likely that these “winter males” undergo more molts to achieve their greater size, and perhaps the bulk is needed to survive the freezing temperatures without feeding much. They could be well placed to secure early matings in the spring.

We traveled about the beach quite a bit, and believe now that the good widow habitat might be more extensive than we previously thought. It will require some careful mapping to determine though.

After returning from the beach, I went up to Mt. Tolmie and saw some more widows, including this large female, who was entirely black underneath. The habitat here is more patchy, but still supports decent widow populations.

At both Island View and M. Tolmie, we found quite a few overwintering cutworms.

Also found a tiny gnaphosid, which may be Sergiolus.

I ended the spidering by uncovering a sleeping Phidippus, under a small rock.

My favourite photos from Guyana

Dec1

In case you missed it, here is a link to the Science Borealis Reader’s Survey: http://bit.ly/ScienceBorealisSurvey. Feedback from this survey will help me better understand my readership.

Sometimes, a lucky circumstance presents itself, and you are ready to seize the opportunity. I got many wonderful photos on my trip up the Rewa River in Guyana this spring, but ironically enough, my favourite set of shots came within the first hour on the boat!

We spotted this hawk on the left bank of the river, and we quietly motored over to it. This was a Roadside Hawk (Rupornis magnirostris), a small, primarily insectivorous hawk found from Mexico to northern Argentina. It has quite a boring name, but it is actually quite lovely and unusual, with a body form akin to an accipiter rather than its Buteo cousins.

Anyway, these were some of the loveliest bird pics I got on the whole trip, so please enjoy them!

The hawk was very obliging as a model, turning this way and that, and looking at us with curiosity.

This view shows how close in body form they come to an accipiter. Short wings, long tail, fine barring on the breast, broad bars on the tail.

In fact, other birds are convergent in form to accipiters, notably in America the forest falcons.

Such a lovely hawk! For larger versions of these images, click here.

Counting wasp attacks: investigating alarm pheromones in yellowjackets

Nov30

This is a post to announce my new paper, which has a bit of a mouthful for a title: Developing a paired-target apparatus for quantitative testing of nest defense behavior by vespine wasps in response to con- or heterospecific nest defense pheromones

This is a paper that was long in the making, and there are two important things you should take away from it: 1) the bioassay setup is cool and 2) three species of the genus Vespula recognize each other’s alarm pheromones

OK, so why alarm pheromones? Well, many social insects coordinate their defences against predators using chemical signalling. These signals can arouse a colony into defensive behaviour, and often can be applied to attackers to attract other workers to attack the intruder. In some cases these chemicals are one and the same, in others, they may be different. No matter! Although our efforts here were part of an attempt to describe the alarm pheromone chemistry of these yellowjackets, we never did succeed in isolating the exact chemicals needed to mimic the naturally-occurring alarm pheromones.

Vespula pensylvanica, the western yellowjacket

Vespula alascensis, the common yellowjacket

Vespula germanica, the German yellowjacket

Many wasp species have their alarm pheromones in their venom sac, and presumably, when disturbed extrude a little venom to signal other workers, or deposit venom on nest predators to “mark” them for attack by the colony. We worked with three species of yellowjackets, Vespula pensylvanica, Vespula alascensis and Vespula germanica. The substances we tested in this study were venom sac extracts of these wasps dissolved in acetonitrile, an easy-to-work with polar solvent.

We dissected out venom sacs (the translucent jelly-bean looking thing) and crushed them in acetonitrile, at a rate of 1 sac per 10 microliters. We filtered the extracts and stored them cold for later use.

To test the effect of the putative alarm substances in these extracts, we needed a bioassay device. Because no standard protocol existed, I designed one that I hope will become the standard for any future experiments:

The paired-target bioassay

In 1995, Visscher and Vetter (yes, that Vetter! The spider guy!) developed a resonant-target attack counter for use in quantifying defensive attacks by yellowjackets and bumblebees. It so happens that when these flying stingmeisters attack, they fly at high speed toward their victim and strike it with force. Visscher and Vetter’s device utilized this important fact by surrounding an audio microphone with a resonant plastic target, and using an electrical counter to count the hits. The device requires construction of the counting circuit, but I thought, why not just record an audio file and count the strikes later?

Basically the device I designed is an elaboration of Visscher and Vetter’s strike counter, only it can be assembled with off-the-shelf components, and utilizes free software to count the strikes recorded to an audio file. In addition, my design is explicitly for use in paired assays, as wasp attack behaviour is often quite variable from one situation to the next, and experiments to test the effect of alarm pheromones can benefit greatly by pairing the treatment and control in each replicate. Think of it as blocking! at 9 am, the wasps are really feisty, and hundreds come out to strike, at 10:30, the attack is less fierce. If we did a control run with a single target at 9, and a treatment target at 10:30, we would be misled, but with a paired design we can determine that our treatment has an effect in both replicates. This saves immensely on the number of replicates required to see a difference.

OK, so here is how the device looks:

The vast majority of the components are very easy to acquire, and the only construction requires a bit of drilling and screwing in of wingnuts and bolts. Everything else is off-the-shelf, and the device folds up neatly for transport and storage. The targets are formed from thin black polystyrene weigh boats, which make a drum-like sound when struck, and they can be disposed of between each replicate so that residual alarm pheromone is not a problem.

Onour Moeri bringing the paired target device to the wasps.

Here is what it looks like when a wasp strikes a target:

The basic process of doing a bioassay is to place the device so that the targets are equidistant from the nest entrance, apply a test substance to one target, a control solvent to the other, start the recording, and then tap the nest entrance to get the wasps activated (note, this step not ALWAYS needed! Some nests are on high alert anyway!)

Here is a video of the device in operation, with audio derived directly from the paired microphones. In this case, the pheromone extract is placed on the left-hand side of the device.

After each assay, the device is removed, the targets replaced, and then the treatment and control are re-applied for another replicate. I always alternated the left-right placement from one replicate to the next, to avoid any side bias.

After a number of replicates (at least 10, better 15 to 20), the audio files are offloaded from the digital recorder, and split into treatment and control files for each replicate. You can use Audacity (a freeware program) to do this.

A simple oscillogram of each file often shows an effect: This is how the two oscillograms look for the left (top) and right (bottom) channels. As you can see, the left hand side experienced more strikes in this short clip.

But how to count these strikes effectively? Well, the solution is another freeware program, SoundRuler, developed by Marcos Gridi-Papp for his teaching in bioacoustics. My application of this software is really wasting its potential, but it works quite well for counting these loud percussive strikes!

In the SoundRuler interface, some simple rules for counting the strikes are programmed in, then automated counting of the entire range desired is simple:

The SoundRuler interface with an open audio file of 240 seconds.

The same file after automated counting enabled. In this case, 123 strikes were counted.

Alright! So that is the development of the paired-target bioassay device, as well as its operation. What did we use it for?

Well, we tested whether three species of ground nesting yellowjackets, Vespula pensylvanica, Vespula alascensis and Vespula germanica have an alarm pheromone in their venom sacs. We also tested whether or not these species would recognize the alarm pheromones of the other species. It turns out that they do!

So what would be the advantage of responding to the alarm pheromone of another yellowjacket species? Well, each of these species has a very similar life history, being ground-nesting, and needing to defend the nest from the same kinds of predators (bears, skunks, raccoons, humans). I can see the advantage of responding early to a “pheromone-marked” predator which had just attacked another species, stinging it and driving it away before it has the chance to attack your own nest. These alarm pheromones probably evolved once in the vulgaris species group, and there was no selection for differentiation, and possibly selection against it.

So there you have it! An inexpensive, easy to construct bioassay device that you can use to test alarm pheromones in large stinging wasps! A counting protocol that is easy and fast! What more could you want? Well, I suggest that the first thing you could wish for is very good luck and/or insight into the complicated chemistry of these alarm substances, but this study has at least provided some new tools to get there.

OK! So that is the paper. I hope you enjoyed it, and be sure to read the whole thing over at the journal website! In the meantime, please enjoy these awesome pictures of the bioassay device in operation.

Drifting on the Rewa

Nov28

To get back to my posting on the trip to Guyana I made this spring, I should get some of the most charismatic megafauna out of the way.

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OK! Are you still with me? Let’s talk about drifting on the Rewa! When we reached our highest-upstream camp on the Rewa, Josey, Brian and Rambo took Jonathan and I out “drifting” several times, basically motoring upstream a few kilcks and then drifting and paddling the boat downstream, in the hopes of seeing wildlife that would otherwise be scared by the motor. We did this several times, most often in the evening to get views of all the animals that come to the river to bathe or drink.

Using the drifting technique, we were able to see several family groups a capybaras, a species I had not previously seen in daylight!

The boat was not as quiet as a canoe, but after days of motoring on the river, this was pretty nice!

The capybaras were often accompanied by large horseflies. Surprisingly, none of these flew over to us, even when their hosts slipped into the river.

The capybaras take to the river when disturbed, and can even navigate extremely fast currents. I remember many times at Parare in French Guiana being startled by big capybaras splashing into the fast-flowing Arataye. This stretch of river was much more sedate, so allowed us to see the animals swimming quite well.

As usual, some of teh capybaras has things perched on them. This is a giant cowbird, which feeds on ectoparasites on the large rodent. Even Black Caracaras do this, but we did not see one doing so.

Drifting quietly also allowed us to spy wildlife we might have missed from going to fast: this iguana was well-concealed at most angles.

We also saw a number of tapirs, which often come to water to bathe in the morning an evening. These are the largest of the South American ungulates, and are very impressive see!

The tapir is a very shy creature in the wild, probably because they are hunted by anybody who can kill them! Unlike capybaras, which breed rapidly, tapir are one of the many species that quickly drop in population with even moderate hunting.

Here was a female tapir we saw at noon, not drifting. I did not get a shot of it, but she had big wounds in her flank, likely from a jaguar or puma. Rather than a relaxing bath, this poor tapir was likely hiding from a predator in the water.

This is what a tapir looks like shaking off!

They look much more elegant when their snout isn’t flapping madly!

Gorgeous animals! We felt really lucky to be able to see so many of these shy and magnificent creatures!

Cheapskate Tuesday 28: Dollar store plant backdrop

Nov24

Catherine and I are living in Toronto, an expensive city to be sure, and our finances our feeling the strain. Nonetheless, money isn’t the only thing in short supply as the Ontario winter bears down on us! The insects around here are pretty serious about winter, and are getting extremely difficult to find! Also, though it has not happened yet, the cold of winter is going to make it very difficult to get out every weekend to turn up new creatures. So we come to studio photography! Having some captive arthropods, it is only natural to want to shoot them, but it gets a bit boring to have them either on white backdrops, or low key and black all the time. While we do have a nice south-facing window, and i can and have used it for a “blue sky” shot, it would be nice to have some foliage! In Vancouver, this meant going out to a vacant lot across the street and clipping some salal, or blackberry or whatever (Vancouver is green!). Here, the lack of green herbaceous matter, especially downtown, is worrisome!

This is Toronto right about now. Nice sentiment on the sign, but the snakes and insects are about as evident right now as the greenery!

Anyway, we do have a dollar store right downstairs, and low and behold, they sell some fake plants. I figured, why not set these up on the wall where I can use them much like a real plant when I am out shooting with the Monster Macro Rig?

2 bucks a pop is not too pricy!

A couple nails in the wall to hang them, and there they are.

For some extra colour and depth, why not put some green paper behind? $1!

Results:

OK, I am getting good exposures, but that green looks way off to me. It is way too bluish for my taste, and does not look natural.

Even with significant adjustments in Photoshop, the green still bothers me. Better to get it right in camera, so back to the Dollar store to find some gels.

For $1.50, I got a pack of “gels” to colour the output of my background light. These are just plastic report covers. I am only using the yellow one, but will keep the rest as well for funky hard lighting somewhere down the line.

With a bit of velcro, gels are ready to attach to the flash.

Man, that YN-460 is looking old! Not bad for 30 bucks though! It has been a trooper!

Results: Yellow-gelled background light

OK! This looks way better to me. And this Rabidosa is looking FINE! Orange spider goggles seem to be in this year.

Here if it looks any cooler, it is because I brought it down in post, but still pretty credible rendition of what lit, out of focus vegetation might look like.

This Kukulcania male on moss is about how I would expect it to look against some actual plants outdoors.

If I pull out far enough, I have to open up a bit. This dock spider shot shows how the “vegetation” looks when a bit more in focus. Still good colour though!

Getting in close shows that the background can still be soft with a big subject. Depth of field is a complicated business!

This debris-covered assassin nymph might prefer to be in the guck of a spiders crevice, but the fake plants in the background have the look of the outdoors.

So there you have it! One way to achieve out of focus vegetation indoors in the studio! Another way to do this might be to print large photos of out of focus plants as backdrop, but I worry about how to light that consistently without getting big glaring reflections from my background light’s head.

This setup is cheap, portable, and nice to have in my bag of tricks. One wonderful thing is that I will never have to worry about that one white stick or grass blade in the background that mucks up a shot before I even realize it. This way, there are no visual intrusions! It is good to know that I have some “outdoor” shooting ability as the icy winter looms!