All posts by Roman Dial

Do Black Spots On Anoles Fool Parasites Into Going Elsewhere?

With regard to the recent discussion of the black spots on the side of A. allisoni:

We saw a bunch of sarcophagid flesh fly larvae infections in canopy-dwelling Puerto Rican A. evermanni. These evermanni were sluggish and often had brown spots either on the shoulder or just dorsal and anterior to the rear legs. I captured some of these lizards and held them in captivity as the flies emerged and the flies emerged in the spots.

Now, our thinking was that the evermanni — a morphologically unspotted lizard — had these spots as a result of the fly larvae damaging the tissue from inside the body cavity. On the evermanni with fly infestations, the soon-to-be-exit holes looked like the “shoulder” spots shown  here on these lizards and on many other anole species.

In contrast, the Puerto Rican spotted A. stratulus had a much reduced frequency of sarcophagid infestation compared to evermanni living in the same canopy habitat and location. These spots often fooled me into thinking that stratulus individuals had been infected, but they were actually just spotted in the shoulder and anteriorly dorsal to the rear leg, where the flies would leave exit holes on evermanni.

One hypothesis is that perhaps morphological spots on spotted lizards fool female flies looking to larviposit on lizards into “thinking” that the lizard is already infected. An infected lizard, when it has visible spots, will soon die, too soon for a flesh fly female’s larvae to survive to the pupal stage, if the female were to larviposit on this dying lizard

I always wanted to do an experiment with the flesh flies and the evermanni and a sharpie, but ….

[Editor’s note: sarcophagid fly effect on anoles has been previously discussed in on AA]