Dead insects are actually wintertime houses in the trees

Scale insects attack plants we care about and poop sticky sugar water on our windshields, and I don’t appreciate either of these very much. But, like most living things, the effects of scale insects on other creatures are complicated, and scale insects also do a lot of things we consider good up in the canopy. I’d argue that scale insects are keystone species, whose poop and leftover carcasses are food and homes, respectively, for many animals and fungi. Here are thrips and mites using scale insect covers and carcasses for homes over the winter.



Scale insects on a time lapse

The scale insect wiggle dance made me wonder about scale insect behavior. The consensus among people who study and think about scale insects is that they don’t move very much. But has anyone ever measured this? I often see the species I work with walking across branches during life stages when they’re thought to be mostly sedentary.

So my tech-savy fiance Joe thought it would be cool to do a time lapse overnight. Here’s the setup.



We filmed a branch with a bunch of 2nd instars and a dead mother scale from 2013. We found these scales didn’t move but that some interesting things happened. See you if you can pick them out. I’ll post what we noticed below the video.

1. Several produce honeydew– this is the glimmering on the one just below the big female.
2. Several also produce wax.
3. Mystery “footprints” show up on the top left branch. I have a couple guesses, but I’m interested to hear if anyone has ideas about what made them.

Some of these are less visible on the youtube version of the video than they are on the raw version. Anyway, we’ll make more time lapses, and it’d be cool to identify the most interesting questions we can answer with this technique. For example, I think it’d be cool to see if the scales produce more honeydew when ants are around. I also think it’d be neat to see if the scales start walking around when the branch starts to dry out to find better places to eat.

It snowed last night, and my Mimi (grandmother) called this morning to see if I was working during the snow day. I said “yes”, and she said “are you working on papers”? Not exactly, Mimi, not exactly. :)