A few weeks ago, we collected the common grass-bush anole Anolis pulchellus around the El Verde Field Station for an enclosure experiment looking at interspecific interactions. We stored the lizards in baggies in the lab for a day or two, moved them to their enclosures for just under three weeks, and we’ve recently finished recapturing them from the enclosures. After measuring their growth and sampling their diets, we put them back where we found them so they could continue on their way with a great story to tell their friends.
One unlucky anole, however, never made it to its enclosure. When I retrieved its bag to take to the experiment site I found the following tragic scene:
The anole appeared to have basically exploded. It looked like foul play, and unlike in the case of other anole-themed murder mysteries, in this case the culprits were apprehended immediately. This poor little (31 mm snout-vent length) guy had somehow been running around out there despite harboring not just one, but five chunky fly larvae inside him.
Just for fun, I kept the larvae in some moist dirt in a plastic container on my desk. I’d largely forgotten about them, but after about three weeks (and only days before we’re due to leave Puerto Rico), the circle of life was complete. Three of the five larvae emerged as adult flies buzzing around the container.
I’ve spent plenty of time looking at aquatic insect larvae from fish stomachs, but I’ll be the first to admit I know next to nothing about adult insect identification. Some quick googling turned up a study by Irschick et al. (2006) looking at the effects of a parasitic fly on Anolis carolinensis in Louisiana. That parasite was a member of family Sarcophagidae – the flesh flies – and it looks like that’s probably what was living inside the poor anole as well. They certainly have the red eyes and striped backs that characterize Sarcophagids, though if anyone can identify it with more confidence please let us know.
Interestingly, I’d noticed that some of the Anolis pulchellus had bumps or nodules projecting from their bodies. This seemed to be especially common in anoles from higher elevations (400-500 m) – this is where the deceased anole came from, though I didn’t notice if he had bumps too. Has anyone noticed these on other species? I don’t know if there’s any connection to parasite infection, but it’s a suspicious coincidence…
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Martha Munoz
Travis – Way cool! As for the elevation differences in parasite load – this correlates well with what we know from the literature. Zippel et al. (1996) found that A. coelestinus and A. cybotes from higher elevation were more infested than their low elevation counterparts. They attributed this to moisture differences between habitats, rather than elevation, per se. Indeed, this summer we counted ectoparasites for an undergrad’s study and elevation alone does not appear to be the best predictor.
Martha Munoz
PS: I just now got your reference to Milton. Certainly the poor dead lizard has discovered the burning lake of Pandemonium.
Maisie
A couple of weeks ago I found a green anole with this parasite and I tried to help it and pulled 6 maggots out of it and just today I found a baby green anole that also had the parasite and it was all ready dead and I don’t know what to do!
Claudia S Copeland
Scroll down for the post by Lanette Vann. She surgically removed them and the lizard was fine! I was so sad when my unfortunate anole died. (Mine ended up having 19 larvae– horrible!) I would love to find out what is going on, and how to prevent this.
Liam Revell
Jason Kolbe, Butch Brodie, Jonathan, & I had a similar incident – I believe also with A. pulchellus – during a field trip back in 2006. If I remember correctly, Jason collected the larvae. – Liam
Yoel Stuart
I’ve seen similar larvae in Anolis carolinensis (at sea level). Some larvae even punctured a hole the skin, as though they needed a hole to breath from, but continued to burrow around subcutaneously. Those anoles were not long for this world.
Ambika Kamath
And the record for the number of such larvae in these A. carolinensis was, I think, 12.
Mimi Quin
Hello… I’m writing from Central Texas. In 2 days I’ve found 2 adult anoles barely hanging on to life and completely overrun by larvae. I gently patted their skin and the larvae started abandoning ship (in this case, the anole. I read the post by Rebecca and share her feelings of being disturbed by the situation, especially after finding the 2nd anole. I wish there was something we could do.
Claudia Copeland
Did the larvae leave through the holes by the lizard’s neck? Or did they explode out? (i.e., did the lizard live?) If you have happened on an easy way to get the larvae out, that would be something at least, if I see another parasitized one. (Did you see the post by Lanette Vann, who did surgery on the lizard?? Impressive…) Most are surely dying without encountering us humans, of course.
Rebecca Sykes
Since I first noticed these parasites attacking the lizards in my yard back in 2012, I’ve continued to see lizards that are affected. Seems like there were fewer the past couple of years but this year I’m once again seeing a large number of them. Most often it is the larger males that are affected but not always. When I find a dead lizard, I place the body in a ziplock bag for disposal hoping to prevent the larvae from developing. I bought a fly trap but not sure if that’s helping at all. Any way to effectively combat or control the parasites? It’s really distressing to see this happening.
Angela
I have seen similar bumps around the necks of some female A. sagrei on Eleuthera (Bahamas). I wonder if they are related to parasites or if they are just abcesses or calcium deposits…
Rebecca
I live in south TX and have been a great fan of green anolis since I was a child. I’ve been quite distressed that over the last few months I’ve found several dead anolis and seen a few live ones that are apparently are infested with Sarcophagid Fly larvae. I’d never even heard of this fly but research has led me to believe that’s what it is.
Is this a serious problem, and is there any way to control these flies?
Jonathan Losos
Rebecca,
there isn’t much known about sarcophagid fly parasitism of lizards, and the little that there is can be found in the paper cited in the post (I can send you a copy if you email me). It is interesting that you have noticed an increased in the frequency, which could suggest that the flies have become more abundant or the lizards more susceptible. Perhaps the drought has weakened the lizards? I’m just guessing. As for controlling them, I suspect we don’t know enough about them to figure out how to do that. However, a quick google revealed that these flies are used by medical entomologists, so perhaps there is more known than I realize.
Rebecca
Thanks, Jonathan. I’m definitely interested in learning more about this situation even if there’s nothing that can be done to control it. I’m still disturbed about this as I’ve never seen anything like it. Sure hope whatever caused this will soon reverse itself. Following is the article I found when first I realized this was going on. In fact, I witnessed an anoli running through the grass being pursued by a fly, and that’s when I first suspected something out of the ordinary.
http://www.anthonyherrel.fr/publications/Irschick%20et%20al%202006%20J%20Herpetol.pdf
Don’t guess running around the yard with a flyswatter is going to do any good.
Phillip W. Rosenbaum
I found your info on the sarcophagidae fly while trying to find out what has been killing my anoles. We live in a small town just South of Houston about 30 miles and we love our green lizards because they are great insect control.
Over the last couple of years, we have noticed lizards dying and they all have holes in them. There are several out there now with large swollen wounds that are scabbed over and they appear to be getting skinnier and poorer looking everyday.
Your pictures match up with what we are seeing. Don’t remember anything like this in our almost 30 years here in the country, only recent years.
Phil
Claudia
We took in a green anole just one day ago, in New Orleans. (Actually, saved him from our cat.) The lizard did not want to go free, so we kept him in a terrarium, but then he got very weak. We took him out to hunt in some grass that’s filled with tiny grasshoppers, and then noticed movement under his skin. He died shortly thereafter, and we set him out, but it really looked like larvae crawling under his skin. Very sad, but he probably did not run from us (and wanted to stay with us) because he was sick…
Lanette Vann
I was cleaning on our back porch today and caught an anole I’ve collected them since I was a child and had like 10 at one time they were all very healthy. But I remember my favorite had a lump in his side and it moved.. I took a scalpel and cut a tiny hole where the movement was and pulled out about 4 little larvae with some needle nose tweezers.. i kept him in a sanitary tank until he healed up. He was fine afterwards. Gained weight and got pretty big.
Claudia Copeland
So glad to hear that you did this! Thank you for sharing. I will follow your example if I ever see anything like this again. (We ended up putting the body of our unfortunate little anole in a jar, and a huge number of larvae came out– 19, I believe. They had digested the whole body within a few hours. This really does make me wonder if something is going on with the lizards and/or sarcophagid flies here. Sarcophagid flies are all over, very common– used in forensic entomology, as they love dead bodies– so it’s not a new introduction of the flies. But perhaps something has weakened the lizards or a new strain of fly has emerged that prefers living to dead flesh?) Did you use anything for anaesthetic?
Ann
just witnessed an upside down lizard (dead) on my elevated deck in Charleston SC area. the legs were moving, so I recorded what I thought was amphibian residual twitching.
I picked it up by the tail in order to toss it out into the grass – when I noticed the cause of the movements.
set it on the deck railing and got to witness the larvae working their way out of the carcass (the hot sunlight seemed to irritate them).
They wriggled themselves free of the anole cavity, then were able to wriggle/roll themselves off the railing (to avoid sun/heat?).
I saved a few in a cup with a wet paper towel … we’ll see what develops.
I have awesome video – if anyone is interested.
(ps: fire ants recently treated in yard, lots of recent rain/heat)
Susie
My husband just found an upside-down, dead Lizard on a house window screen. When he took him down the larvae started crawling out and he crushed them. I recently nursed a large anole back to health that had two holes on each side. I didn’t notice any larvae on him, in fact I thought some other animal bit him. He’s fine now but only sticks his head out of whatever he’s hiding in when he sees me. Poor Lizzy. I’m just totally grossed out because I wonder if these flies can lay this larvae in dogs. My daughter has dug these out of her chickens. Wth??? We are in NW Florida.
Kenneth J Hicks
I’m not an expert on these, but what I have been able to find out is: 1) these type of maggots tend to infest particular hosts. Those more than likely went for smaller lizards. Others infest toads while still others go after turtles; 2) there has been conjecture that usually flies will seek out weaker, older, etc. individuals. However, during ideal situations for the flies, healthy creatures are infested as well. There’s a guess that these could be warnings of weather conditions say, a particularly warm or humid summer. But as for your dog, s/he should be fine because they are looking for reptile, amphibian etc. host.
Heather
Found an anole in Alabama with a hole in its side. Comes to visit often to bask in a certain spot outside my office. I noticed the hole was getting larger and larger and the body of the anole was brown while around the hole was green. Found him dead today with multiple larvae coming out of him. Came on here to see what they could be. Thanks for all the information!
Heather F.
We have had four cases of lizards being infested by this larvae here in Wilmington NC in the historic downtown area. This is extremely disturbing as we have a healthy population of this type of lizard and they are so much fun to have around. Just this morning we spotted the fourth in our garden with its abdomen moving. It caught a insect and seemed okay. The first one noticed was just a couple of weeks ago. The larvae was dropping out of a hole on the lizard. The second and third time both lizards were dead. Though this summer was extremely hot and humid (nothing abnormal for our area) the fly population wasn’t that noticeable. Really curious what’s going on here.