Category: All Posts Page 29 of 154

Anolis cristatellus predating on Eleutherodactylus martinicensis; photo taken by Jeanelle Brisbane

In the (sub)tropics of the Western Hemisphere, it is not uncommon to come across sleeping anoles while strolling around at night in (partially) vegetated areas; they are after all considered diurnal. It was therefore quite a shock when active anoles appeared in the beam of our headlights during the nights of 18 January and 16 April 2019 on the Commonwealth of Dominica. On the first night, we observed how a juvenile Anolis cristatellus (non-native) jumped from one grass style to the next and successfully caught a fly; on the second night, the adult A. cristatellus had a still alive and resisting, frog (Eleutherodactylus martinicensis) in its mouth (see photo).

An increasing number of anole species are being found to utilize artificial light sources after sunset, and thereby extend their activity period, allowing increased growth and fecundity. What made our encounter especially unsuspected was the absence of artificial light in the area we were surveying for the removal of newly arrived alien species. Instead, these nights (waxing gibbous with 91.7-92.9% visibility) were close to the full moon, and without cloud cover. Our observations were at 19:59 and 20:40h, almost 2 hours after the end of astronomical twilight; it was night.

The area of our observations consists of several abandoned plots nearby the harbor, overgrown with grasses, vines, and bushes. The edges of this open area are partially made up of a single line of trees, shorter than 7 m in height.

Our observations indicate a potential understudied part of anole ecology, though more observations are needed to understand the occurrence of this behavior, both within and among species. However, ex-situ, some authors have already demonstrated that anoles show activity under moonlight conditions, which appeared more evident for shade-adapted species.

In our paper just published in Neotropical Biodiversity, we discuss several to-be-tested hypotheses and address how our observations could shed new light on anole predation by nocturnal predators, like owls and bats. Beyond anoles, observations of nocturnal activity by diurnal reptiles have been reported on some occasions. The observations of this behavior in Anolis are of special importance given the large body of literature and understanding of these model species; allowing the scientific community to test hypotheses and move beyond observational reports.

Excitingly, since the publication of our work we have been in contact with enthusiast readers of which one indicated to have observed moonlight-facilitated activity as well but did not write that up, yet.

Matt R. Whiles, Chair and Professor in the Soil and Water Sciences Department at the University of Florida provides these details:

Specimen was not captured, just photographed by my wife Lindsay Hsieh, who is familiar with Anolis and recognized that it was different looking.  Observed in Alachua county FL, west of Gainesville in a horse barn facility – coordinates: 29^O 41’08”N 82^O 30’18”W;  date was November 10 2020.  A. carolinensis are common on the barn, but none we’ve seen look like this.  The owners of the facility routinely haul horses back and forth from Gainesville to south Florida, so could be a transplant.”

He then asks: “I’ve seen thousands of A. carolinensis, and never one like this.  Do you think this is just a color/pattern display, or would this individual always look like this?  We are keeping an eye out for it again and will try to collect it if you want the specimen.”

Thoughts, anyone (including interest in the specimen should it be seen again)? My guess is that these are not  permanent markings; the block spot on the head and the hint of an erected nuchal (neck) crest suggests a stress response; perhaps the lizard had just been fighting. Indeed, Dr. Whiles clarified in a subsequent email: “I’ve certainly seen the black spot form on stressed individuals, but never the full patterning.  To add to your hypothesis, my wife indicated it was interacting with another Anolis when she saw it (you can actually see the tail of the other individual in the pic).”

Aryeh Miller and Ansley Petherick

Which anole species will grace the pages of this year’s calendar? Pictured here is Anolis capito. Photograph by Aryeh Miller.

Thanks to all of you that have sent in photos for our calendar contest! For those who haven’t sent anything yet, now’s your chance – the deadline to submit is at the end of THIS WEEK (this Friday, November 13), so if you plan to submit, be sure to do so soon!

To remind you, the rules are here:
Submit your photos (as many as you’d like) as email attachments to anoleannalsphotos@gmail.com. To make sure that your submissions arrive, please send an accompanying email without any attachments to confirm that we’ve received them. Photos must be at least 150 dpi and print to a size of 11 x 17 inches. If you are unsure how to resize your images, the simplest thing to do is to submit the raw image files produced by your digital camera (or if you must, a high quality scan of a printed image).  If you elect to alter your own images, don’t forget that it’s always better to resize than to resample. Images with watermarks or other digital alterations that extend beyond color correction, sharpening and other basic editing will not be accepted. We are not going to deal with formal copyright law and ask only your permission to use your image for the calendar and related content on Anole Annals (more specifically, by submitting your photos, you are agreeing to allow us to use them in the calendar). We, in turn, agree that your images will never be used without attribution and that we will not profit financially from their use (the small amount of royalties we receive are used to purchase calendars for the winners). Please only submit photos you’ve taken yourself, not from other photographers–by submitting photos, you are declaring that you are the photographer and have the authority to allow the photograph to be used in the calendar if it is chosen.

Please provide a short description of the photo that includes: (1) the species name, (2) the location where the photo was taken, and (3) any other relevant information. Be sure to include your full name in your email as well.

Thank you and good luck!

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.“