The local common name for these social wasps is marimbondo-chapéu in Portuguese or hat wasp in English. The name refers to the form of the nest, seen above.
Seen from below, I’d say it looks more like a sunflower. They are really packed in there. I’d estimate there are probably a couple of hundred of them.
Here’s another crop that I like of that same image.
You’ve probably noticed by now these images were taken during the day. So what are all of them doing hanging out on the nest? Taking a siesta? I wondered the same thing. I spent around 45 minutes taking pictures and attempting to gauge just how closely I could approach without alarming them. During that whole time, not a single one flew off or arrived.
I began to wonder if these wasps might be nocturnal. When I returned a few hours after dark, I had my answer. At that point, the nest was quite active, with dozens flying around. A quick internet search for “nocturnal wasps Brazil” gave me the genus, Apoica, a genus known for its nocturnal habits.
When reviewing the images, I noticed they have relatively large ocelli, which undoubtedly helps them navigate and find prey at night.
Most of these photos were taken with my 100mm macro, sometimes combined with my teleconverter. The closest I ventured was for this habitat shot, taken with my wide angle zoom at its widest 18mm setting.
I don’t have my copy of Latin American Insects with me, but I just checked it via google books. Hogue refers to this genus as parasol wasps, also because of the shape of the nest. He notes that only the common species, Apoica pallens, has a yellow abdomen.
When I spotted these paper wasps alongside the trail, I only halfheartedly took a few shots. Mostly, I just didn’t think I’d be able to get an attractive photo out of it. So when I was reviewing my shots, I just about deleted all of them, including this one.
At the last second though, I noticed something unusual in the photo. I call these sorts of discoveries where I notice something in the photo that I didn’t realize was there when I took it “easter eggs.” It happens often enough that I just decided to add a new category for that here on my blog.
Back to the photo though. What caught my eye are the little black things in a few of the cells near the top center of the nest. Zooming in, you see this.
I assume those are some sort of parasitoid flies or wasps. You can see a few paper wasp eggs at the top. I’m not quite sure what to make of the contents of the cells with the adult parasites. There’s an extra little white blob with the one on the right. Could that be the parasitoid larva? If so, why would there be an adult in the cell with it? Seems too big to be a parasitoid egg. And what are the pinkish blobs with the adult on the left and in the lower right? Are those the parasitoid larvae or is that what the paper wasp larva look like at that stage?
As usual, I have many more questions than answers. I’d love for someone to help fill me in if they know what’s going on here.
This has definitely fueled my curiosity though. I’m likely to brave some stings and try to get some closer and better focused shots of nest cell contents on future encounters.