Poison Ivy Caterpillar / Dimorphic Macalla Moth

May 20th, 2012 - 4:36 PM | Filed under Featured Photos | 3 Comments

For many years I’ve noticed colorful little caterpillars that live individually in silken retreats on the surface of leaves of poison ivy. At a recent BugGuide gathering, a photo of one of these caterpillars was shown and I realized we still didn’t know what these were. I resolved then to rear a few to try and arrive at an identification. There’s plenty of poison ivy near my home, so I didn’t anticipate much trouble finding a few.

Here’s the first one I found. The white area just behind the head is atypical. The caterpillar is smaller than usual, so it might be an early instar. It could also represent some sort of injury.

13mm | August 20, 2011 | Roswell, GA, USA

The next day I collected another one, larger.

20mm | August 21, 2011 | Roswell, GA, USA

The next weekend I collected one more.

20mm | August 27, 2011 | Roswell, GA, USA

Here’s a cropped version of the image above, showing the head. Checking these specimens and other photos on BugGuide, there appears to be quite a bit of variability in the head coloration. They all have a white band across the lower part of the head capsule though.

Closeup of head

At that point I figured I had a good chance of successfully rearing at least one.

The last one I collected was the first to pupate. A few days before pupating it started to change color. That’s not unusual for caterpillars as they prepare to pupate. In this case it darkened to become more orange.

Prepupal stage of final instar | 9 September 2011

Another closeup of head

I neglected to photograph any of the pupae.

Earlier this month, an adult eclosed. It’s attractive and quite distinguished looking with an elaborate headdress.

20mm wingspan | 4 May 2012

Lateral view

Front view

Closeup of head

After searching through various guides, I decided this must be what’s currently known as Macalla superatalis. My books actually identified it as part of a genus it was previously placed in, Epipaschia. The common name, Dimorphic Macalla (previously Dimorphic Epipaschia), refers to the fact that it comes in two color forms: green as above, or tan.

Having arrived at the identification, I checked BugGuide and found that someone had beat me to the identification based on a literature search. Oh well, it looks like I might be the first there to have successfully reared them though.

References:

A Field Guide to Moths of Eastern North America
by Charles V. Covell, Jr.
Peterson Field Guide to Moths of Northeastern North America
by David Beadle and Seabrooke Leckie

Tapinoma Ant Observations

May 2nd, 2012 - 10:31 PM | Filed under Featured Photos | 1 Comment

April 13, 2012 | Twelvestones, Roswell, GA, USA

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.

Moving out

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.

That's not an ant

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.

About to right itself

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.

Follow the larvae

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.

Dorsal view

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.

Dorsolateral view

Both the specimens I captured have ovipositors and so must be female.

Frontal view

Rear view

Another shot

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.

Queen

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.

References:

American Insects:
A Handbook of the Insects of America North of Mexico

by Ross H. Arnett, Jr.
Field Guide to Grasshoppers, Katydids, and Crickets of the United States
by John L. Capinera, Ralph D. Scott, and Thomas J. Walker
Ants of North America:
A Guide to the Genera

by Brian L. Fisher and Stefan P. Cover

Another Unidentified Caterpillar

April 30th, 2012 - 10:04 PM | Filed under Featured Photos | No comments

~30mm | January 7, 2012 | Tupaciguara, Minas Gerais, Brazil

Even though I can’t identify it, it’s pretty enough that I had to post it.

Leafrolling Mystery Caterpillar

April 29th, 2012 - 7:43 PM | Filed under Featured Photos | No comments

20mm | April 5, 2012 | Twelvestones, Roswell, GA, USA

Earlier this month I was checking for anything interesting in my backyard when I came across this caterpillar in a rolled up leaf on viburnum. I decided to try and rear it to get an identification.

It turns out it was a final instar because it pupated beneath its leaf within a week, sometime around the 9th.

Pupa within leaf shelter

I removed the pupa from its webbing for some cleaner shots.

11mm | Underside of pupa

Dorsolateral view

I checked daily for the adult, but sadly it eclosed while I was away on vacation, sometime around the 20th give or take a few days. When I got back I found a dead and beat up adult. I prefer live images of a fresh adult that I can release later, but I’ll take what I can get here I guess.

10mm | Adult

Based on similar looking moths, I decided it must be a Tortricid moth in the genus Archips. Looking through all the species images on BugGuide, I decided it most resembled Archips grisea.

It has what appears to be a costal fold on the forewing, indicating it’s probably a male.

Note enlarged area near base of forewing

This page has a description of the larva which is consistent with the caterpillar I found. One distinguishing feature is a completely black head and prothoracic shield.

Uniformly black head and prothoracic shield

The page also says the first pair of legs are black while the other two pair are pale green and unmarked. Check.

Leg colors consistent with larval description

Everything suggests this is Archips grisea except the host plant. Either this is something else, or viburnum hasn’t been recorded for this species.

I’m asking for some expert help here. If it checks out I’ll update BugGuide as there are currently no larval images for this species (or anywhere on the internet that I can find) and no record for Georgia.

Membracis Treehoppers and Nymphs

April 29th, 2012 - 6:15 PM | Filed under Featured Photos | 4 Comments

~10mm | January 7, 2012 | Tupaciguara, Minas Gerais, Brazil

When I spotted a group of treehoppers like the one above, I settled in for a while. With such a beautiful subject, I was determined to get some good photos. The shot above is probably my favorite out of around 300 or so shots. I struggled to get something in the background to avoid the usual black background that usually happens with macro flash photos. A black background wasn’t going to serve very well for these mostly black treehoppers.

Not only are the adults pretty, but the nymphs are also attractive in their own way. I prefer the black background here.

5mm | Nymph

The treehoppers cluster together in small groups.

Adult with nymphs

Somewhat surprisingly, these treehoppers didn’t appear to be attended by any ants.

More nymphs

I thought this exuvium was interesting. The interior is orangish, like the spikes on the abdomen. I suppose the base color is really mostly orange with black spots. The white color must really just be white scales.

Exuvium

They were on a good sized tree.

Underside of host branch

While looking around for an identification, I encountered a similar looking species on this plate from the Biologia Centrali-Americana identified as Membracis foliata. This article indicates there’s been confusion around that species though, so it could very well be one of the other species mentioned there (unfortunately I can’t access the full text).

Dictyopharid Planthopper with Dryinid Wasp Parasite

April 18th, 2012 - 8:50 PM | Filed under Featured Photos | 1 Comment

~20mm | January 7, 2012 | Tupaciguara, Minas Gerais, Brazil

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.

Closeup of 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.

Thread-legged Bug with Spider Prey

April 16th, 2012 - 9:29 PM | Filed under Featured Photos | 1 Comment

30mm long | December 30, 2011 | Quirinópolis, Goiás, Brazil

This thread-legged bug appears to be hanging in mid-air, but in fact it has delicately balanced itself on a spider web. Its beak holds a small spider that it must have just plucked from the center of the web.

Some thread-legged specialize in spiders, and I wonder if this might be one of them. Some are even known to lure the spider by plucking at the web like captured prey might.

Another view

A Couple of Dictyopharid Planthoppers

April 15th, 2012 - 9:29 PM | Filed under Featured Photos | 1 Comment

10mm long | December 30, 2011 | Quirinópolis, Goiás, Brazil

These dictyopharid planthoppers are a nice addition to my virtual collection.

It took many attempts before I got this shot where both planthoppers were in the plane of focus. That’s sometimes difficult enough with small subjects, but even more so when they are above your head. I convinced myself the Canon 60D’s flip-out view screen with live view would come in handy for situations like this. Shots like these that I’d otherwise have missed make me feel better about the expenditure.

Clearwing Moth

April 9th, 2012 - 9:52 PM | Filed under Featured Photos | No comments

~20mm wide | December 31, 2011 | Quirinópolis, Goiás, Brazil

This colorful moth in the family Arctiidae looks a little worse for wear. Nonetheless, it’s quite striking and I’m sure a fresh specimen must be even more so. I later saw another one of these near a porch light so it might be a common species.

While searching for a possible identification, I came across this blog posting. It describes how hundreds of caterpillars were invading people’s home in Piracicaba, São Paulo. With the help of a biologist, they found both the host plant and some pupae for rearing. What emerged looks very much like the moth above, identified as Cosmosoma teuthras, a common moth throughout Brazil. Check the site for photos of the caterpillars, pupae, and an adult. I have no idea if there are similar looking species, but it seems like a good possibility for what I found.

Identification Challenge #14 Reveal: Arched Hooktip

April 7th, 2012 - 11:00 AM | Filed under Identification Challenges | No comments

27mm wide | March 24, 2012 | Twelvestones, Roswell, GA, USA

No one commented on the latest identification challenge. Despite showing just the tip of the forewing, the image provided showed the distinctive feature of a subfamily of moths commonly called hooktip moths. If you got that far, it’s a pretty simple process of elimination since there are only a handful of North American species, each one easily distinguished from the other. This species is the Arched Hooktip, Drepana arcuata.

This individual appears to be a male, based on the widely bipectinate antennae.

Male, based on antennae

As I mentioned in the original post, this moth was reared from a caterpillar I encountered late last year. They feed on alders and birches. I found this one on alder, within a leaf it had folder over using its own silk.

Sheltered within a folded alder leaf | 20mm long | October 29, 2011 | Buford, GA, USA

I raked my fingertip through the silk, in order to get a clearer view.

Clearer view

These caterpillars have enlarged warts, shown here.

Closeup of enlarged warts

It’s actually quite a handsome caterpillar. Note the bands on the head capsule, which no doubt inspired its common name, Masked Birch Caterpillar.

Frontal view

One other interesting thing about these caterpillars is that they scrape or beat parts of their anatomy against the leaf in order to advertise their presence to neighboring individuals. In this way they can space themselves out and avoid unnecessary competition.

Reference:

Caterpillars of Eastern North America
by David L. Wagner