Back in 2013, AA featured a number of posts discussing whether and how often bats eat anoles. The discussion ended with a report of a paper documenting extensive anole hunting by the big-eared bat in Panama (see photo above). That paper described how the bats captured their prey: “M. microtis hunts on the wing, checking leaf by leaf in the forest while hovering up and down the understory vegetation.”

Now, a new study has used DNA metabarcoding of fecal samples from the frog-eating bat, Trachops cirrhosus, and has discovered that the bat needs a new common name: the frog-and-lizard-eating bat. That’s right: although DNA from a variety of frog genera was found in the bat poop, the second most common taxon (inhabiting 22% of the turds) after Pristimantis frogs was anoles!

The study did some other clever things as well in an attempt to figure out how the bats found their prey. Here’s what they say in the discussion:

“We found DNA from Anolis lizards in almost a quarter of our bat samples, but bats showed a fairly low response to the rustling sounds of anoles moving through leaf-litter. A previous anecdotal report from Honduras described finding a dead anole in the mistnet pocket with a female T. cirrhosus (Valdez and LaVal 1971). Anoles do make alarm sounds, but do not call, therefore we anticipate that the rustling sounds made by anoles moving through leaf-litter is the most obvious cue they present to T. cirrhosus. We had hypothesized that we would find greater responses to anole rustling sounds in dry season conditions (lizards moving through dry leaves) than wet because movement through dry leaves produces louder, more conspicuous rustling sounds. While we did find anoles in the diet of more T. cirrhosus in the dry season than in the wet season, and we did find higher response to the sounds of anoles moving through dry versus wet leaf litter, these differences were not significant. Why bats did not show more response in general to anole rustles is unclear. One possibility is that since the speaker was in a fixed location, the rustling sound does not move in space as a real moving animal would. Additionally, rustles are relatively low amplitude compared to the mating calls we presented to the bats, which could account for the lower responses. Also, anoles are diurnal, therefore we might not predict them to be moving around at night, and rustling sounds could be indicative of many different potential prey, some more palatable than others. Bats may thus be locating anole prey by some other mechanism than rustling sounds, and one bat did attack a silent, motionless plastic anole model, indicating that T. cirrhosus may be able to locate sleeping lizards using echolocation alone. Anoles are diurnal, so unless one was scared off of its perch, they are unlikely to be moving through the leaf litter at night.”

And just because it’s so cool, I have to add the beginning of the next paragraph:

“Diet samples indicated some predation events that appear to be rare, including predation on the hummingbird F. mellivora, and on the bats Glossophaga soricina, C. perspicillata, and Micronycteris microtis.“

Jonathan Losos
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