When the (human) is at the door

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Gray wolves in Alberta. Photo by Paul Paquet.

 

We have an expression “when the wolf is at the door” meaning that bad times are upon us, and poverty/ill health is looming. This implies a feeling of despair and anxiety, and when the wolf is at the door, it is likely that our hormonal systems reflect our stress.

So too with the wolves, when humans are at the door, so to speak. Recent research by Heather Bryan shows that both stress hormones and sex hormones seem to increase as a result of human persecution.

Dr. Bryan and her team quantified hormones in hair from wolves from populations which varied in the level of human persecution: tundra/taiga wolves from Nunavut and the Northwest territories, and boreal forest wolves from the Northwest territories and Alberta. The tundra/taiga wolves experience on the whole a greater level of persecution than those in the boreal forest, but Dr. Bryan also examined an outgroup of boreal wolves with high levels of persecution.

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Cortisol is a hormone which is produced under various stressful conditions, such as injury, starvation and social conflict. Tundra/taiga wolves had greater levels of these hormones than wolves from the boreal region. The increases associated with human hunting pressure could reflect changes in the social structure wrought by mortality of members of these tight-knit groups of animals.

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Likewise, Bryan observed increases in progesterone and testosterone with hunting pressure, perhaps as a result of disruption of pack dynamics brought on by excess mortality. In wolf societies, breeding females (the mothers) suppress reproductively mature subordinate females (usually their daughters) reproduction, resulting in a pack structure in which only the dominant female breeds. In packs with unstable social conditions, as when hunting removes individuals, this suppression of subordinate reproduction is interrupted, which could result in population-wide increases in sex hormone production.

Dr. Bryan also notes a possible confound in the comparison of the two groups: the tundra taiga wolves also differ in their ecology. These populations have much greater long-distance movements as they follow migrating herds of caribou, and the increased cortisol may reflect the stresses of these long-range movements.

Nonetheless, this study provides an fascinating glimpse at the inner lives of wolves. It will be very interesting to see what follows from this research, especially if we can determine how the hormonal state of populations influences their behaviour.

 

 

 

Weekend Expedition 60: Feast of the otters

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Vancouver is known for hockey riots, the North Shore mountains, and cheap sushi. The last of these items was on the menu yesterday at Stanley Park’s  Lost Lagoon, where I found a group of  river otters at an all-you-can eat buffet.

 

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When I saw the first otter, I thought it was a beaver, as it was swimming around the base of the beaver lodge at the west end of the lagoon. When it popped its head up, I realized my mistake.

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I found two otters here, both of them feeding on small Common Carp (Cyprinus carpio), an introduced species common in Lost Lagoon.

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Both of these otters seemed to be pretty rapidly catching the fish, and were consuming them at a great rate.

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After a short time, a small crowd had gathered to watch the otters at work.

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One of the otters came up on the far bank.

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I was not surprised to see it engage in a little rolling and scent marking, something I have seen and written about before.

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Then the second animal emerged on the same bank I was standing on (about 3 m away!)

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It too did some rolling around! I could not get the whole otter in frame due to its proximity.

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After a short time, bot otters swam west, upstream into the sun. There, they joined up with some more otters I had not noticed previously. Now there were at least 6 otters in total.

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Here too the otters were feasting on carp. They seemed to be very successful, coming up with a fish only seconds after diving. I was beginning to suspect that the recent cold snap may have debilitated these young carp.

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Here are a couple shots of a social interaction, which looked more like playing than true aggression.

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In the previous aggressive interactions I have seen, the otters vocalize. These ones were quiet.

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I watched the otters fish for a couple hours. In that time, I lost count of how many fish were being eaten.

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The otters ate rapidly as well, and you could hear the bones break as they hacked into the fish with their teeth.

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They seem to close their eyes as they eat, probably an adaptation like sharks have when putting their face close to potentially dangerous prey.

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As the sun started getting low on the horizon, the otters headed east toward the lagoon proper. They probably den elsewhere, perhaps in the harbour. Overall, this was the best photography session I have ever had with otters, and I was so glad I came to the park when I did. To see some of these shots at a larger size, click here

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Date with an ant

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Last week, Catherine and I went out to see “Interstellar” using free points racked up on my ScotiaBank (“We’re richer than you think”) debit card. Since we had not had dinner, we headed up to Stepho’s, a Vancouver Greek restaurant with generous portions and low prices (Their price for a 1/2 souvlakia has increased by $2 since 1989). This was already an awesome date, with dinner and a movie, but what really made my night is when Catherine returned from the ladies room and presented me with this awesome ant.

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I identified this as Tetramorium species E, what is commonly known as the pavement ant. This is an introduced species or member of one of several introduced species that is quite common in some cities in BC. I have found that populations are most dense in the suburban sprawl of Richmond.

Thinking to photograph her after the movie, I imprisoned her (the ant) in a pill bottle and sprinkled some wetted sugar into the container to keep her sustained. I then promptly forgot about her until this morning!

To my surprise, she was still alive, and so I set up a macro rig consisting of the Canon 50mm on 62 mm of extension tubes capped off with the Raynox DCR-250. I photographed her on a piece of grass against the wood floor at f16 and  ISO 400 using a diffused YN-560 at 1/4 power.

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These myrmecines do not move very quickly. They are quite aggressive with other ants though, and are often seen engaged in major battles during the summertime. You can see the out-of-focus highlight to the right of the ant is pentagonal, due to the 5 bladed aperture of the inexpensive Canon lens.

 

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The constrains of the close subject distance meant that the flash was positioned somewhat behind the subject, but I like how this highlights the setae.

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The future looks bleak for this individual, as she is now parted from her colony, which is probably huddled in a little ball somewhere below the ladies room of Stepho’s. I will continue providing her with sugar as long as she lasts though, and maybe try some more shooting later on.

Photo session with a jumper

IMG_5050This weekend, I did not have much time to go out and shoot, so I got my photography in by taking some shots of a Phidippus johnsoni female we are keeping in the apartment. In some of these shots, I was trying to mix hard and soft light to show the hairs of teh spider more clearly, but with the activity of the spider, it became a bit of a free-for-all regarding lighting.

Update: I am not sure if this is Phidippus johnsoni. It may well be P. borealis.

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Here is the spider just before leaping. The extended forelegs are characteristic of an about-to-leap jumper.

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This is the effect I was going for with the bare flash to the rear.

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The colour of the chelicerae seems to depend hugely on the angle of light. Not surprising, as this seems to be an example of structural colouration.

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Here they are with more direct lighting.

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When not tearing around the tabletop studio, the jumper liked to hide in the dried leaves.

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Slender in the grass

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‘”Though nothing can bring back the hour of splendor in the grass, glory in the flower, we will grieve not; rather find strength in what remains behind.”  -Wordsworth

It seems to me that I have not posted in some time. For various reasons, I have not had much time or energy for photography or blogging recently. I do manage short bursts of inspiration, and I have plans for a few more in-depth posts, but for now I can only offer this gorgeous Tibellus oblongus that I shot the other day while digging for ants.

These slender spiders are members of the Philodromidae, or running crab spiders, and are most at home lying on grasses and slender twigs as ambush predators.

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Here is one I photographed this summer showing her hunting prowess.

 

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Their longitudinal stripes help them blend in with the substrate, and they are quite tricky to spot until they move.

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I found this individual, as well as one more buried in the soil beneath a clump of tall grass.

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I find the lines of these spiders very elegant, and they are definitely pleasing to photograph.

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Next time you are out in a grassy meadow, keep an eye out for these cryptic hunters!

Weekend Expedition 59: A fungal outing to Lynn Canyon

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This Sunday, Catherine Scott, Mike Boers, Tanya Stemberger and I went out to Lynn Canyon, to take in some of the fungal delights of mid-fall. I used to be a much more avid mushroomer than I have been recently, so it was great to get out and exercise my rusty ID skills.Here are some of the things we saw!

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Catherine looks amazed that Tanya is going to live-tweet our fungal expedition.

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This is the cheaper version of the Capilano suspension bridge.

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Here is a very pretty Lactarius.

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Lactarius bleeding its “milk”.

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Here is a chopper employed by North Shore Search and Rescue, combing the river for a missing hiker. With wilderness at your doorstep, as in Vancouver, these types of things happen frequently.

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Ground-based searchers examine the river.

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Mike gets overtaken by a man with a musclebound dog who pulled him up the slope. This is really the best way to  hike!

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Something so calming about looking at these trees on a fall day.

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A luridly orange patch of witch’s butter on a fallen log.

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Here is a fungus gnat on what might be a Mycena.

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Newly growing caps of what may be Naematoloma.

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An Elfin Saddle! This is Helvella lacunosa (or something similar), a species I used to pick and eat quite a bit.

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Mushrooms are challenging subjects…I hope to get a chance to do more serious photography of them one day.

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Since Tanya had yet to see a salamander, I uncovered this Ensatina for her to examine. As expected, this was a big hit. Ensatinas are probably the cutest of BC amphibians.

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Catherine and Tanya examining the salamander, Catherine looks spooked, but this is normal (and has nothing to do with the Ensatina).

Lace Bug!

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Last night I brought a pile of leaves into our apartment to try some more spider shooting in a controlled environment. To my surprise, this little lace bug (Family Tingidae) must have come in  on the leaves.

Tingids are one of my favourite bugs, as they look like they were sculpted from stained-glass. This one has a really crazy pronotum, which looks something like a radar dome.

I hope you enjoy these shots of our unexpected visitor!

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Last Gasp of Arachtober

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For the very last post of Arachtober, I thought I would take some shots of the Halloweeniest spider on the west coast, Dysdera crocata. These orange and red beauties are specialist predators of terrestrial isopods (pillbugs) and have fangs equal to the task of envenomating these armoured prey.  IMG_2658 IMG_2683 IMG_2710 IMG_2712 IMG_2750 IMG_2756

 

Best two wasp nests I ever spent: the case of the Black-throated Antshrike

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Female Black-throated Antshrike. Photo by Phil Stouffer. What an impressively fierce-looking bird!

Remember my post last week on the White Woodpecker preying on wasp nests? Well,if you browsed that issue of Revista Brasileira de Ornithologia, you may have noticed that I published an article on a similar topic!

This is another account of a bird preying on wasp nests, one that was completely unexpected. This involved the Black-throated Antshrike, Frederickena viridis. Black-throated Antshrikes are members of the Thamnophilidae, or antbirds, a largely Neotropical family known for being associates of army ants. Basically, these birds “attend” army ant raids and parasitize the ant colony by quickly grabbing the insects, lizards and arachnids that flee the approaching ant swarm.

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Eciton burchellii army ants. These impressive swarm raiding ants kick up quite a lot of prey from the leaf litter, which antshrikes are only too happy to steal.

During fieldwork in 2010, we caught a male Black-throated Antshrike is doing its own dirty work, striking wasp nests, causing the wasps to abscond, and feeding on the brood. Here is the video (edited for time, as the whole attack sequence  lasted 42 min):

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A: Polybia scrobalis B: Polybia bistriata

The two wasp species in question were Polybia scrobalis and Polybia bistriata, which we had placed in a video arena for our experiments documenting Red-throated Caracara feeding behaviour. In some ways, you could say that the antshrike was parasitizing us!  This was all recorded as intended by our automated video system, which reacts to motion in the video stream and records the action with a 5-s pre-recording buffer. On that morning, my field assistant Tanya Jones and I were just getting up and having breakfast when this antshrike was attacking. By the time we were done breakfast, the antshrike was too!

A few things to note: Unlike their behaviour with the Red-throated Caracaras, this Polybia scrobalis colony fought back. At 0:30, 1:22  and 1:45 in the video, you can see wasps attacking the antshrike, and in the second two instances, the antshrike plucking off the wasps.

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Wasp on antshrike at ~30s

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Wasp on antshrike at 1:22

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Wasp on antshrike at 1:45

 

For comparison, here is an attack on the same wasp species by Red-throated Caracaras:

So why do the wasps attack the antshrike and not the caracaras? Can these wasps can evaluate the threat posed to the colony and adjust their defence/retreat appropriately? Maybe the wasps somehow evaluate the odds of successfully driving away a predator and abscond if nest defence is likely to be hopeless. After all, the workers which are killed in nest defence are still a loss. Continued defence piles up the losses, and if defeat is inevitable, it is better to retreat with your worker force intact.

Alternatively, it could be that the colony the caracaras attacked was worse off in some  way, and more likely to abscond, but the possibility remains that wasp defensive behaviour against vertebrates is plastic.  There is definitely room for some exciting research here.

Considering the White Woodpecker, the Black-throated Antshrike, and the Red-throated Caracara (among others) it seems that more and more vertebrate predators are being found that prey on wasp nests. In these cases, it appears that the birds are minimizing the risk of stinging by inducing the absconding response of their swarm-founding prey before moving in close to feed on the larvae.

While I was a little upset that these nests fell to the antshrike rather than giving me more data on caracara predation, getting a paper out of it and learning something new was well worth it.

 

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Male Black-throated Antshrike. Photo by Phil Stouffer.

Some Arachtober shots and thoughts

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October is a month for spiders, being the time when many of the species which have grown large on summer’s bounty are settling down to lay eggs, or looking for overwintering sites. For spider photographers, it is like golden hour all month! If you search flickr for “Arachtober” you will find the photographic bounty that macrophotographers have amassed.

This Arachtober, I have not really been applying myself to spider photography, although I have made some dedicated efforts to secure shots of black widow defenses (for Catherine’s invited  talk at last weekend’s ESBC conference), or Steatoda males and females, for my friend Chloe Gerak’s award-winning talk at the same conference.

Anyway, here are some shots and thoughts about my Arachtober.

 

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Western black widow throwing silk on Catherine’s finger at Island View Beach.

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Catherine gave a great talk on “dangerous spiders” at the ESBC conference, her first 1/2 hour talk. Her t-shirt (thanks Alex Wild!) serves as a great abstract of the talk.

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Female Steatoda grossa with a bit of backlight highlighting her web. False black widows around here are not very black!

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Chloe after delivering her awesome, award-winning talk entitled “How the false widow finds true love”.

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Male and female Steatoda grossa juxtaposed for comparison.

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A largish sac spider (Clubionidae) showing the large chelicerae typical of the family.

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Putting the light a little behind the spider can help resolve some of the surface details and maintain a bit of mysteriousness at the same time.

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More direct light makes for a less moody feel as the sac spider drinks water on a colourful leaf.

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Arachtober is also a scary time for spiders. Here is an emesine thread-legged bug I found in a spider retreat, where it was likely feeding on spider eggs.

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Fall foliage makes for a wonderful seasonal backdrop for this Hallowe’en spider villain.

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