Gray-fronted Dove

 

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This post is gonna be short; Catherine and I a prepping for a very long roadtrip to Texas, LA, and eventually to BC to start Catherine’s field season. This is just a video of a Grey-fronted Dove (Leptotila rufaxilla) feeding nestlings at the Nouragues Station in French Guiana.

This nest was right beside the showers in camp, and to get this footage, I set up my camera and started recording, leaving it there until the card filled or the battery ran out. This was a labour intensive process, as the majority of clips recorded were just the bird sitting there and the chicks sleeping.

I think that this clip of feeding made it all worthwhile though, as it gives a rare view of how the chicks “plug in” to the adult to receive their meal of “crop milk

Weekend Expedition 71: Mississauga salamander hunt

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After a week of warmth, Gil Wizen and I set out for the same woods we visited last week, in order to see if we could find any salamanders out to take advantage of the vernal pools. The snow was completely gone, and the pools ice-free, although it was overcast and a nippy 5 C.

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There were flies and moths out on the vegetation, indicating at least that the insects have begun to wake up.

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Even a male orb weaver was out, although he did not have a capture web.

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Near the vernal pools, we started to flip some logs, hoping for a treasure rove of salamanders, but initially we found only millipedes, beetles and some small red-backed salamanders.

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There were quite a few firefly larvae in the rotted wood, as well as some rove beetles.

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Very close to the vernal pools, Gil found this Jefferson’s Salamander, Ambystoma jeffersonianum. This (to me) was a big beast, dwarfing the longtoed salamanders from BC. This species is endangered in Ontario, although it is common in other parts of its range.

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They are a difficukt species to capture well in a photograph, and for this shot I stood off at a distance and used the 300 mm. Luckily it was overcast, and the light in the forest was diffuse. The salamander was quite motionless, and probably was not pleased about being out in daylight.

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We replaced the big amphibian, and wished it well. Soon, hopefully, many of its fellows will come down to breed in these little vernal pools.

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We also found a few redbacked salamanders, which are a species of plethodontid. These animals have no need of open water to breed, and in fact lay their eggs in moist soil and wood, hatching out into juveniles with legs already formed. They are lungless, and never need gills either!

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These Plethodon are a bit easier to photograph, although they might have benefited from a more diffuse flash.

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After leaving Gil to pack for his coming trip to Ecuador, I found my way home was blocked by a big St. Patrick’s day parade. It was scheduled to last several hours, so I crawled through the awful Toronto traffic to Tommy Thompson Park to kill some time until my annoying relatives had cleared out of town. I found a couple of nice sac spiders under some bark.

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These Clubiona have very impressive chelicerae, but never seem to threaten to use them. Instead, they are very prone to jumping when disturbed.

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I found some European fire ants under a rock, and took some photos. They were still rather lethargic, and hence not much of a stinging hazard!

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They are quite pretty little ants, and Toronto seems to abound with them now.

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Here a worker antennates a queen. You can see her much-enlarged thorax and wing scars.

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Despite their wings, the queens do not disperse by flying in North America, a trait they seem to have lost. In addition, the colonies here are often much larger than those in Europe.

 

Weekend Expedition 70: Mississauga/Credit River

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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.

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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.

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Catherine and Gil on the way to the forest.

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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…

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

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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.

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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.

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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.

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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!

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

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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.

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

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

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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

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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!

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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.

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

These bark crab spiders are extremely flat!

These bark crab spiders are extremely flat!

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

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

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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.

This shot shows the sac spider’s eye arrangement.

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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.

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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.

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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!) 

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

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

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

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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

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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).

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

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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

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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!

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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.

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

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Just love the little mustaches on these bold woodpeckers!

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

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

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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

IMG_9607Catherine 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. )

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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.

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

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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.

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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.

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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.

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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.

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

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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:

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

 

 

Serious gull baths

20151231-IMG_2691Catherine 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.

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Some winter spiders at Island View Beach

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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.

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

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

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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.

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

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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.

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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.

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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.

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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.

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

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Also found a tiny gnaphosid, which may be Sergiolus.

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

 

My favourite photos from Guyana

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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!

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

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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.

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

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

 

Counting wasp attacks: investigating alarm pheromones in yellowjackets

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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.

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Vespula pensylvanica, the western yellowjacket

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Vespula alascensis, the common yellowjacket

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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.

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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:

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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.

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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.

 

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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:

 

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

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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!

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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.


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