At least when it comes to finding their nest entrance…
Because our great leader Obama said “mow less” (in his recent Presidential Memorandum), so I skipped two weeks of mowing, i.e. this is about 21 days after last time I mowed!
My wife told me there was a yellowjacket nest in the back yard, so I carefully moved that area first, by first blocking their hole with a stone, then blasting some pesticide toward the 200 also foragers coming back, and finally letting the mower working on top of the entrance for 3 minutes. These gals have much stronger mandibles! they chewed their way out in no time (about an hour). There was another, smaller nest about 2 ft away and the same thing. This morning, at 11 degrees C, I was wondering if they were foraging. They were! they work harder than honey bees, who would not venture out until its about 15C. They were also not as defensive as honey bees, if I put a mower right next to a strong hive, I would be hammered by bees, but the yellowjackets did not seem to associate me with the mower or the pesticide coming to their home (again, not as smart?).
So at around 5:30 pm I was mowing the front yard, I did not know there was another nest! suddenly wasps started coming to my hair and I had to run into my garage. Luckily I did not get stung. I remember my first one was about 10 times more painful than a honey bee sting! I had this throbbing pain, shooting from my sole of right foot (walking barefoot on deck got me there) to my head for 4 hours, with 2 hours of which I could not move my leg. My second one in Spain was not as painful (one got under my camera belt and stung my chest) but it was itchy for a good 3 days.
Soon after I saw about 100 wasps flying around, but low on grass. At that time I thought they were just confused or perhaps trying to find me to sting. But this morning when I checked them, they were doing the same thing! They were flying 1-3 inches above ground, hovering around an area of 3×4 meters, but mostly east side of their hole. They were confused! They must be using the small “landmarks” created by the not-mowed grass (here is dandelion stalk, that should be 5″ from my home…), once the grass is moved back to a quite homogenous area, they could NOT find their way home…But it is now 10:30 am in the morning! I did a few video using my phone. I might go back using a better camera again. I checked the two at the back, where the grass was not as tall, they are not exhibiting this behavior.
This tells me several things: 1). Yellowjackets use small landmarks near their nest, similar to honey bees. But unlike honey bees, 2). They do not use odor, honey bees will use odor once close to their hive. Of course yellow jackets might not have odor coming out since their “house” has no ventilation, unlike honey bees wooden hives (artificial). 3). Yellowjackets do not use visual cues (hey, these wasps found the hole! let us follow them…), they are pretty single minded and each is trying to find their way home without paying attention to others. and finally 4). They do not mark the entrance with pheromone. honey bees will “scent” using secretions from their “Nasonov glands” near the tip of their abdomen and fanning their wings, essentially saying “come in, girls, our sweet home is in this direction!”.
I will keep an eye on these wasps to see how long they will be confused. They must have been doing that for 3-4 hours between 5:30 and now (11:18am).
Too bad I will be gone for a while and when I come back, they will be all dead. Otherwise i will play some interesting tricks with them. For example, I can plant a small flag next to their hole, guiding the wasps home (will the searching stop right away?). After a day, I will move that flag 5 meters away, how many wasps will be hovering there at the flag? Oh, the tricks you can play with bugs! (I used to do this to ants when I was 4-6).
P.s. wasps continued to search a large area at 2 pm. but at 4 pm, they seem to have got it. still they fly low and then find the hole after 0.5 to 2 minutes. Still confused but not aimless searching. The species I think should be Vespula germanica (family Vespidae).