I had planned to post just a single photo of this scene with ants tending treehoppers. Here we see at least two different colorful treehopper instars, with one actively molting. Ants like the one shown above tended to this small grouping of treehoppers. As I was choosing a photo to post, I noticed something strange about the treehoppers though. Do you see it too?
Look closely and you’ll see that a few nymphs have parasites. I wasn’t sure at first, so I started looking through my other photos. Sure enough, almost every one had one or more parasites. The parasites seem to prefer hiding under the wing pads and below the thorax.
Most of the parasites were small, but there were at least a few plump ones.
None of the photos provided a clear view of the parasites, but I suspect they are mites. In any case, apparently the services provided by the ants don’t include grooming.
For several days I had noticed ants racing along the bricks at the base of one of my garage doors. I finally took a closer look to see what could be keeping them so busy for so long. They were streaming between a hole in my house and somewhere out in the front yard. I tried following, but these ants are tiny, only a few millimeters long. I quickly lost them in some pine straw.
Turns out they were moving out of my house. The ones heading toward the yard were carrying eggs, larvae, and pupae. As I watched them though, I noticed something else leaving with them that didn’t look quite right.
When I first saw one of the critters above, I knew it wasn’t an ant. My initial thought was it must have been a tiny roach. That first one was gone before I could react, but I headed inside to grab some containers in hopes of seeing more. Over the course of an hour and a half, I spotted three more and managed to grab a couple of them.
Watching one, it seemed unsure of its course. At times it would bump against some incoming ants and dart away. It would always rejoin the column, but sometimes moving in the wrong direction.
Eventually it would right itself, almost always after encountering an ant carrying a larva or pupa. I’d guess it can’t follow whatever chemical signals the ants are tracking and instead relies on following the cargo.
It got me wondering how the ants know which direction to go in. I know they follow a chemical trail, but what tells them which direction they should go? Actually, lots of questions came to mind as I watched them. How do they know it’s time to move? How do they decide on a new nest location?
Later, I gave the freeloaders the white paper treatment.
I began to wonder if these weren’t crickets. I grabbed Arnett’s American Insects and started skimming the cricket families listed there. When I came to Myrmecophilidae (Ant-loving crickets), I figured that must be it. I briefly thought I might even be able to contribute something to BugGuide, but it turns out there were plenty of photos there already, confirming the identification.
Both the specimens I captured have ovipositors and so must be female.
I found some good info on these in my Field Guide to Grasshoppers, Katydids, and Crickets of the United States. These crickets only live in ants nests. They apparently feed on oily secretions from the ants bodies, causing no ill effects. Only one species occurs in my area, the Eastern Ant Cricket, Myrmecophilus pergandei. This particular cricket species has been found living with eleven different species of ants.
Speaking of ant species, I decided to try and identify the host ants. Using the key in Ants of North America: A Guide to the Genera, I arrived at Tapinoma. Based on the remarks there, I believe these ants must be Tapinoma sessile. I sacrificed one to see how well the common name of Odorous House Ant applies. It was indeed odorous, and as I mentioned, they were leaving my house.
As I watched the ant column, one other thing caught my attention. Fairly often, I’d notice a much larger ant passing by, about twice as big as the others. I snatched one of those as well.
Remembering some of Alex Wild’s comments from his blog entry on how to identify queen ants, I recognized this as a queen. That only confused me though, since I had seen perhaps half of dozen of these in the brief time I observed the column. I naively thought that ant nests generally had a single queen. The wikipedia entry for this species says that its nests can actually have hundreds of queens!
I wasn’t familiar with either of these interesting insects when I started watching them. Had I encountered them a week later though, I’d probably have recognized them from a recent post from Alex Wild. He scooped me, but I couldn’t let the opportunity to blog about them pass.
What happened to the ants you might be wondering? Well, they can’t seem to make up their mind. As I write this there is still a column going strong, weeks later. They were steadily moving out for almost a week, but then at some point I noticed they had reversed course and were moving back in. I don’t want to imagine just how many thousands of ants there are somewhere in the walls of my home.
When I encountered the planthopper above, I had no idea what was going on. While not entirely sure, I assumed that might be a parasite on its abdomen. I had wanted to get a closeup of just the parasite, but when I went to grab the planthopper, it jumped and flew away with little difficulty. The parasite must not have been as much of a hindrance as it would appear.
Here’s a crop of the image above showing the parasite.
It didn’t take much searching on the internet to determine that this must be the larva of a wasp in the family Dryinidae. There are plenty of images of larvae on BugGuide. According to Wikipedia, a larva initially feeds internally on the host. Only later in its development does it protrude the host as shown here.
I feel lucky to have seen this. As is usually the case, this just whets my appetite for more. Now I’ll be on the lookout for the odd looking adult.
Leafcutter ants are a common sight in the Brazilian cerrado. I admit to being apathetic when it comes to photographing them. In order for me to turn my lens on them, something unusual generally has to be happening. In this case, I first noticed something odd occurring around one of the nest entrances. Looking closer, I could see the ants were being attacked by a small fly. I had read about that, but had never seen it personally. Intrigued, I figured I’d spend a few minutes shooting, even though I fully expected to end up with nothing usable. I was pleasantly surprised that one of the images managed to get both an ant and the fly in focus.
The fly was almost constantly in motion, occasionally dive bombing an ant. I assume this is a female fly in the family Phoridae. Look carefully above and you can see the fly’s ovipositor.
At one point I saw a fly at rest near the nest entrance, possibly the same fly as above.
Each one of these eggs from the underside of a leaf was parasitized by a wasp. Their barrel shape with round fringed caps suggests they might be stink bug eggs. Had a stink bug nymph emerged, the caps would have been neatly opened. Instead, they each have a roundish hole chewed in them. In fact, there’s a parasitoid wasp straggler chewing its way free from the rightmost egg.
I might be seeing things, but you can almost make out the wasp’s body through the transparent egg shell.
I didn’t notice at the time, but a mite came along.
Metamorphosis for this butterfly appears to have been interrupted by a parasite, a small wasp perhaps. You can see the hole where the parasite chewed its way out. Oddly, there’s a similar hole on the other side. Maybe it abandoned this other exit since it looks incomplete. Or maybe there were actually multiple parasites.
I know this is the chrysalis of a brush-footed butterfly in the family Nymphalidae because other butterfly families use a a small silken thread around the thorax to help secure it. Here’s an example from an earlier post.
Butterfly chrysalises can be quite intricate and this one has some interesting flourishes.
Can you spot the spider corpse here? Looks like it succumbed to some sort of fungal infection. Fungi are quite diverse and I don’t recall ever seeing one quite like this one. Here’s a closer view.
I suspect that webbing is probably from the spider itself. It probably was hiding inside a silken retreat when it died.
Would the fungus properly be called an arachnopathogen? I think so but there’s practically no hits when I search for that term.
I did find a photo with a similar looking fungus on BugGuide though. Sadly, no info on the identity of the fungus. It’s neat to see that the photo was taken not too far from where I live though.
Am I the only one that wonders if I should be wearing a surgical mask when I get close to something like this?
Despite its defenses, this caterpillars appears to have ended up with some parasite eggs, a tachinid fly perhaps.
I collected this little chrysalis while I was in the field the day before I took this photo. I didn’t think I’d be able to get a good photo at the time, and I was curious to see what might emerge. Strangely, looking at this with my own eye, it appears opaque with a silvery and gold surface. With the camera and flash, it appears as above, somewhat transparent and showing what looks like a wing inside. I figured it would only be a short time to see the butterfly that might emerge. Well, I was half right.
About a week later, I found this in the rearing container.
With those enlarged hind femora this must be something in the superfamily Chalcidoidea, perhaps in the family Chalcididae. The natural history fits, since Chalcidids are parasites of Lepidoptera and Diptera pupae.
Here’s what’s left of the chrysalis.
The more I observe nature, the more I realize that parasites rule. So far this trip, I’ve accumulated dozens of photos to prove my point, including the one above.
Believe it or not, this caterpillar was still alive. The parasites, wasps presumably, are long gone.