Thursday, 16 May 2013

How I Defeated the Hornets

    Today, a friend linked to a story about a Swedish man stung to death after attempting to mate with a hornets' nest. Having been stung by a yellowjacket myself, I found it difficult to imagine anyone actually inviting such a painful experience in such a sensitive area, but hey, there are crazies out there, right? Of course, this particular story is likely a hoax, according to this site.
    Nonetheless, the tale reminded my of something I'd been meaning to write up since last summer, when I discovered a thriving hornets' nest under our deck. While I am by no means an expert on extermination, perhaps my experience will be useful if you find yourself in a similar situation.

     It first crossed my mind that there might be a nest there when I noticed a yellowjacket land on the deck and then crawl down between the boards. As I pondered this, another landed in almost the same spot, and also disappeared between the 2x6es. Not wishing to be stung, I fetched a little mirror-on-a-stick gadget I have in my toolchest, and knelt down on the sidewalk next to the deck, a good two meters from likely location of the nest, based on the wasps' entry point.
     This was the only time I was stung during the entire operation, and at first I thought I had just bumped my wrist on an exposed nail or something. But there was no blood, no obvious sign of a puncture wound, only the characteristic swelling and pinkness that goes with a sting. And it hurt like crazy.
     The sting established a few things. First, it confirmed that there was indeed a nest present, and second, it was probably closer to this end of the deck than I thought, if I was so promptly attacked way over here. But it also established the commencement of hostilities between myself and the Vespulan colony, a war that would end with their utter destruction.

Phase I: Recon
     I considered what I knew of my enemy. Yellow jackets, like true hornets, bees and ants, are eusocial. That means the individual workers are more than happy to sacrifice themselves to protect the hive, but there's no benefit to the hive if they throw their lives away attacking something that isn't a threat. So presumably, even when they get all riled up, they probably won't chase you too far. And so I planned a raid to probe their defenses.
     I have a nice long stick with a natural hook at the end I use for picking apples. I wrapped cardboard around the end of it to make a kind of giant flyswatter, and approached the deck, after making sure there were no human noncombatants in the area. I saw a yellowjacket returning from foraging, and slammed it to paste with the swatter before retreating to the other end of the yard to observe. Almost immediately a dozen or so angry insects emerged and buzzed around in a combat patrol over the deck, their numbers growing as others presumably made their way from deeper in the nest. But they didn't stray much farther than two or three meters from base, and didn't seem to identify me, five or six meters away, as a target.
     I carried out a few more probing raids, standing a little closer to observe each time, but fleeing whenever a Vespulan got too close to me. In this way, I learned just how far they would pursue before breaking off the chase, valuable intel to inform the next phase of my campaign.

Phase II: Harassment and Attrition
     Interesting thing about yellow jackets. They are primarily predatory, bringing back insects and chewed up bits of carrion to feed the larvae, who secrete a rich sweet sugary fuel for the adult workers. Later in the season, when they focus on fattening up the breeders instead of feeding new larvae, the adults tend to shift their feeding habits to sweet stuff like fruit, which is why you'll sometimes see them buzzing around your root beer at picnics.
     Flying is a pretty energy-intensive activity, which is why the adults need more sugar. This was mid-July, the raspberries weren't falling off the bush yet, and the hive was still growing lots of new workers, so most of the Vespulans' flight fuel was still coming from larval secretions. Strategically, then, they were highly dependent on foraging. This became my target in Phase 2, the war of attrition.
     Each day, I made several harassment raids on the Vespulan colony, whacking the deck loudly with my swatter, retreating to just outside of their usual pursuit range, swatting targets of opportunity as they presented themselves. On a typical raid I might kill half a dozen workers, but that was just icing. Six dead workers meant six fewer foragers, but more importantly, forty angry wasps buzzing around defending the hive meant forty angry wasps delaying their foraging trips, burning up fuel, and needing to tank up again before going out to collect protein for the larvae.
     The attrition phase took a week or so, and eventually my persistence began to pay off. Fewer and fewer defenders emerged to meet each attack. Even so, I could not assume I had simply killed them all; presumably the higher fuel demands had caused more workers to be diverted to foraging, keeping a smaller combat reserve to defend the hive. But in any case, the groundwork had been laid for the final phase of the campaign.

Phase III: The Ground War
     The time had come to finish off the hive. By observing the Vespulans over the course of the campaign to date, I had a fair idea of how long it would take for them to be able to regroup after a raid. I also was fairly certain that the hive was attached to the underside of one of three adjacent 2x6es on the deck, which would need to be removed in order to carry out the final assault. I assembled the gear I would need: crowbar, swatter, a can of Raid (which in hindsight I probably didn't need). I also suited up with my fencing mask, a leather jacket, and work gloves, to reduce the likelihood of being stung.
     The assault began with a swatter raid, just like previous attacks, except that at this point my objective was to kill all of the defenders, not merely to harass them. There were few enough at this point that I was able to do so.
     Once I was satisfied there was no Vespulan in a position to sting me, I grabbed the crowbar and pried up the middle plank, where I hoped the nest would be attached. I had to move fairly quickly, as I wanted to finish this before returning foragers were able to join in the defense. Alas, the plank I removed was clean; the nest was attached to the next one over. I sprayed a goodly dose of Raid directly into the nest's entrance.

     As I said, in hindsight, I probably didn't really need to use chemical weapons. At the time, I didn't know how many adult workers might yet be inside the hive as a last reserve against intruders, but I assumed there would be some. Indeed, there were a few, but I probably could have squished them without being stung, with sufficiently aggressive tactics. Alternatively, I suppose I could have put duct tape over the entrance. I shall always have to live with having made that decision.
      In any event, I next grabbed the hoe and used its blade to scrape the nest free from the underside of the adjacent plank, and it fell to the ground under the deck where I couldn't conveniently reach it with my gloved hands. So I trotted to the garage and got a spear-like implement we have for weeding dandelions, and skewered the hive, bringing it out onto the sidewalk. Now it was just the mopping up.

     A couple of adult wasps did crawl from the entrance to the nest, but they were in no condition to attack me. The insecticide was already doing them in. With the nest on the sidewalk, some distance from its original location, any returning foragers were likely to go into a confused "Where the heck is my house?" search mode, rather than angrily seeking vengeance. (Insect brains are very small.)
     Still clad in my anti-sting armour, I began to dismantle the nest, which was a fascinating and beautiful structure. There were several layers of cells, many with larvae in them. I felt a pang of regret, but only a little. The hive was in a bad place, and as the summer progressed, it would become more of a  nuisance, so close to our main thoroughfare to the garage. Besides, one of them STUNG me! They started it!

    That said, I am not a sworn enemy of all yellow jackets. They're actually fairly beneficial creatures, preying as they do on many insects we consider pests. They don't seek out people to sting, tending to conserve their venom for when they need to defend the nest. As alarming as it is to have one buzzing around your plate in late summer, I don't think I can remember ever being stung by one that was out foraging, nor seeing someone stung under such conditions. Had they built their nest a bit more remotely, say, behind the garage, out of pursuit range from human routes, we could have peacefully coexisted. Alas.


  1. [pedant]Yellowjackets aren't hornets. They're genus Vespula wheras Hornets are genus Vespa. They're both members of the subfamily Vespinae and the family Vespidae. Technically they're both Wasps.[/pedant]

  2. Now that I've got that out of my system. :)

    In our neighbourhood there are wasp nests every year. When they choose my yard I like it when they pick a nice exposed spot but that's rare. A few times they've chosen a spot in my deck and planters that can't be taken apart except destructively and last year they found their way into the eves of my house. Thus my tactics have been primarily chemical warfare using a combination of foaming insecticide and, once the numbers appear to be suitably diminish, foam insulation in a can as deep as I can get it. Seems to be generally effective but definitely easier when I catch them early.

    A few years back the whole neighbourhood was being terrorized and we nobody could find the nest until one day walking down the alley we spotted it hanging off the corner of a house in a sheltered spot. The nest was over two and half feet long top to bottom. Professionals were contacted for that one.

  3. Argh! I thought I'd corrected that, because I did make a point of distinguishing between yellow jackets and true hornets in a later paragraph. Must've missed the first one in my edits.

    Two feet, huh? That's huge! Must've been home to six or seven thousand workers, which would certainly lead to a notable neighbourhood population. But was anyone actually stung, to your knowledge?

  4. Not sure on actual stings. Wouldn't surprise if there were, yellow jackets are fairly aggressive. I was stung last year by one in the house although I can't blame the wasp. It was sitting on my desk and I put my arm down on it.

    When I took out the big nest I took out from the inside the eaves I easily had over a hundred carcasses of wasps that managed to crawl out of the nest. Not sure how many were inside but it was a busy place.

    You're definitely right about their range of attention. When taking out the one last year I would push the tube into the nest, spray like crazy they retreat up the roof a little over two meters. Angry wasps would swarm out but not notice me that far away.

  5. Late summer they get 'tetchy, and require no provocation for their attacks. Their representative opened hostilities in the summer of 78. There will be no detente, there will be no negotiation. I will strictly enforce my personal No-Fly Zone.

  6. 5 words: shop vac filled with water.
    It's fun to watch them on final approach being sucked into the gaping void. (Not referring to Madonna)