Category: All Posts Page 15 of 145

Shai Meiri, School of Zoology & the Steinhart Museum of Natural History, Tel Aviv University
uncshai@tauex.tau.ac.il

In late April 2021, someone posted a facebook image of a lizard seen in a residence garden in Rishon LeZion, a satellite city of Tel-Aviv, Israel (approximately 31.9611N, 34.7889E). Aviad Bar, one of the best herpetologists in Israel, identified it as a brown anole (Anolis sagrei Duméril & Bibron, 1837) and went there to investigate. He found around ten lizards in that garden, and managed to catch two of them. The preliminary identification was verified, and the lizards were later deposited in the national collections at the Steinhardt Museum of Natural History, Tel Aviv University, after the Israeli Nature and Parks Authority (INPA; the governmental body in charge of protecting nature in Israel) were consulted.

Anolis sagrei is potentially very bad news. It is one of the best models for the study of evolution in nature over short time scales across the animal kingdom (a more or less random sample of works includes: Losos et al. 2004, Schoener et al. 2005, Calsbeek and Cox 2010, Losos and Pringle 2011, Stuart et al. 2014, Kamath et al. 2020, Stroud et al. 2020, Donihue et al. 2021). But it is also one of the worst reptile invaders worldwide, alongside flowerpot snakes (Indotyphlops braminus), the mourning gecko (Lepidodactylus lugubris) red-eared sliders (Trachemys scripta – we have those in Israel now too) and some Hemidactylus geckos (e.g., H. turcicus, which we may have helped to provide; H. frenatus). To date Anolis sagrei has invaded several states in continental USA (e.g., Florida, Louisiana, Texas), as well as Grand Cayman Island, Bermuda, Jamaica, Grenada, St. Vincent, the Canary Islands, multiple areas in Mexico, Belize, Honduras, Costa Rica, Panama, Ecuador, Hawaii, Taiwan, and Singapore (Sexton and Brown 1977, Kraus 2009, Norval et al. 2012, Amador et al. 2017, Capinha et al. 2017, Stroud et al. 2017, Solis et al. 2017, Batista et al. 2019).

Furthermore, Anolis sagrei is known to compete with native anoles, mainly Anolis carolinensis a system very frequently studied (reviewed in Kraus 2009, and see e.g., Echternacht 1999, Losos and Spiller 1999, Gerber and Echternacht 2000, Stuart et al. 2014, Kamath et al. 2020). Effects on other anoles were also suggested (Losos et al. 1993 for A. conspersus; Batista et al. 2019 for Anolis gaigei), and competition with other lizards has been hypothesized (e.g., Stroud et al. 2017, Batista et al. 2019). Thus, a new record of A. sagrei from outside its native range is no cause for a celebration.
How did A. sagrei reach Israel? One hypothesis, raised by INPA, is that eggs have been transported accidentally in shipments, likely from the USA. We know A. sagrei eggs remain viable for weeks, and can even withstand some exposure to sea water (Hsu et al. 2021). There is a plant nursery not far from the place where A. sagrei was found in Israel, and reptiles have often been accidentally transported with plant shipments (e.g., the flowerpot snake; see e.g., Perry et al. 2006, Losos 2013, Auguste et al. 2018). Indeed, a shipment of wood from Italy arriving in Israel early in 2019 contained live Podarcis siculus (specimens were transferred to the Steinhardt Museum of Natural History, and I identified them there). The USA is the #1 exporter of goods to Israel and considering A. sagrei is widespread in the US, it is a reasonable assumption.

A more plausible explanation soon emerged, however. Anolis sagrei has been in the pet trade in Israel for some time. Some third-party reports to Aviad Bar suggested that a private reptile enthusiast living in Rishon LeZion has been very successful in breeding Anolis sagrei and has simply been releasing juveniles or hatchlings into his back garden. Apparently, this has been going on for at least two and potentially 4-5 years. Thus, the source of the invasion seems to have been intentional (and illegal) introduction of individuals to nature.

The INPA asked me to write a report on potential threats posed by the brown anole and its chances of establishment and spread (Meiri 2021), then held a consultation, and commissioned Aviad Bar to survey the anole population in Rishon LeZion, and adjacent natural areas. Additionally, other Israeli herpetologists have tried to find the species around the area where it was first reported. The survey encountered some unexpected difficulties. For one, the recent horrible and useless spat of fighting between Israel and Hamas, which could and should have been avoided by both sides, caused unnecessary suffering on both, and seemed to have served only the extremely short-term purposes of “leaders” of both sides. Lizards had nothing to do with this apparently. The fighting forced the surveyors to stop the survey multiple times to take cover in shelters of complete strangers from incoming rockets. Luckily, none of them was hurt. Many people welcomed the surveyors into their garden and allowed them to look for and collect lizards. The survey (Bar 2021) was recently submitted to the INPA.

Anoles have been found in five streets in Rishon LeZion, with a maximum linear extent of ~500 m. Lizards have been found active by day on walls, fences, vegetation and on the ground, and to sleep on branches at night – typical anole behavior. Worryingly, anoles of all sizes, from adults >60 mm SVL to small hatchling-sized individuals, were found throughout the study area, strongly suggesting the lizards breed in Israel. Anolis sagrei breeds extremely fast, especially in regions where it is invasive where it matures early and reduces its already incredibly short inter-laying interval (e.g., Jensen et al. 2008, Fetters and Mcglothlin 2017). Basically, one gets the impression (or at least I do) that introduced Anolis sagrei lay eggs (almost) as fast as domestic chickens. It seems to further be helped by light pollution – growing faster and reproducing earlier where artificial lights are available at night (Thawley and Kolbe 2020) – like they are in Rishon LeZion.

Anoles were also highly abundant. Aviad (Bar 2021) found 101 anoles during his survey, and Akiva Topper and Oren Kolodny have found 28 in a single night. For comparison, the second most abundant reptile found during Aviad’s survey was the common chameleon, Chamaeleo chamaeleon – with 15 specimens. The third most abundant was the commensal (and in Israel, native) house gecko, Hemidactylus turcicus (10 animals). In fact, only 41 reptiles other than A. sagrei were found in the survey, of all species (including those identified only from tracks!). Thus in terms of abundance, A. sagrei seems to outclass all other reptiles put together by a factor of at least 2.5-to-1. That this species can be extremely abundant in places it has invaded is well known (e.g., Campbell and Echternacht 2003).

While A. sagrei has invaded many places the world over, it seems to have been confined to tropical or subtropical countries (and the subtropical parts of the USA), and this is the first report of it inhabiting higher latitudes and non-tropical climates (except perhaps some potential places in the USA). One hope expressed early was that the relatively cool Mediterranean winters prevailing in central Israel will prove detrimental for anoles. Yet, like it probably does in some cities in the USA, A. sagrei seem not to mind what goes for winters near the Mediterranean coastlines of Israel. A combination of the climatic effects of the warm puddle that is the eastern Mediterranean Sea and warm microhabitats likely found in urban residential gardens seem to allow it to easily survive the winter. Watering of said gardens likely allows it to easily survive the arid climate of the long Israeli summers (where very little rain, if any, falls in April or October, and virtually none in between). Thus, urban areas seem to present for the anoles the kind of climate and microhabitats it thrives in in its native and introduced range.

Could it spread outside of the cities? As far as we know following Aviad’s survey (Bar 2021), no anoles were found in natural areas bordering its current urban distribution. The little water available there for most of the year may preclude its establishment. But it is highly likely that, if accidentally transported, it could easily establish in habitats where abundant water is available year-round. Such as streams and pools, artificial and natural.

How much of a threat is posed by Anolis sagrei to Israeli nature is less certain. As far as I know few have tried to estimate its effect on arthropod and other prey-species communities (but see Losos 2011,2020). I certainly cannot guess it. Actual reports of Anolis sagrei impacting other vertebrate taxa seem to be confined to its effect on congenerics (even Stroud et al., 2017, only mentions potential impacts), of which Israel has none. But a super-fecund, and highly abundant, species such as the brown anole could potentially compete with other small terrestrial and arboreal lizards (and juveniles of larger species), of which the Israeli coastal plain has many (Bar et al. 2021). I can easily envision it competing with, and potentially preying on lizards such as Mediodactylus orientalis, Hemidactylus turcicus, Phoenicolacerta laevis and Heremites vittatus – at least juvenile ones (and it could easily prey on adult Ablepharus rueppellii, if it can find it in the grass and leaf litter).

Right now, probably 2-5 years after it first invaded, A. sagrei seems to be doing extremely well in its new introduced range in Israel – but it is still probably very localized. This means that we have a unique opportunity to deal with it before it spreads further. Our record of dealing with reptile invasions in Israel is abysmal. Few reptile species have been introduced to Israel: Cyrtopodion scabrum, Trachemys scripta and more recently (Jamison et al. 2017) Tarentola annularis (Meiri et al. 2019, Bar et al. 2021). As far as I know, no attempt has been made to stop the spread of C. scabrum and T. scripta. The story of T. annularis is even more telling. Despite being larger, meaner, and potentially far more aggressive species than A. sagrei, and being introduced to a single locality, very little has been done to try and curb its invasion. One person was employed, for a few months, to try to control what was already a population numbering in the thousands – and even this effort was stopped for lack of funding (read: being of very low perceived priority).

I hope this will not be the case with Anolis sagrei too. We have the potential to stop the invasion, still in its infancy, in its tracks. The INPA seem to have the will (and certainly has the means) to do it, and I wish them luck and perseverance. This is an outlet of anole lovers so please don’t get me wrong. I do not wish for Israel to be the next test case of fascinating scientific work on the rapid evolution of Anolis sagrei. We want to keep anoles those wonderful and lizards we read about in papers and books (e.g., Roughgarden 1995, Losos 2009). I want us to keep on having to go and find them in places we find exotic (if there is anything Rishon LeZion is not, it is exotic). I want to engage with the scientists who study them on their own turf. Let’s keep anoles in the Neotropics where they belong.


References
Amador, L., Ayala-Varela, F., Narvaez, A. E., Cruz, K. and Torres-Carvajal, O. 2017. First record of the invasive brown anole, Anolis sagrei Dumeril & Bibron, 1837 (Squamata: Iguanidae: Dactyloinae), in South America. Check List 13: 2083.

Auguste, R.J., Dass, K. and Baldeo, D. 2018. Discovery of the Puerto Rican crested anole, Anolis cristatellus Duméril & Bibron, on Trinidad. Caribbean Herpetology, 63: 1-2.

Bar, A. 2021. Summary of a preliminary survey to evaluate the establishment and distribution of the species brown anole (Anolis sagrei). Report to the chief ecologist of the Israeli Nature and Parks Authority, Pazbar, Herzlia. In Hebrew.

Bar, A., Haimovitch, G. and Meiri, S. 2021. Field guide to the amphibians and reptiles of Israel. Edition Chimaira, Frankfurt Am Main. In Press.
Batista, A, Ponce, M., Garces, O., Lassiter, E. and Miranda, M. 2019. Silent pirates: Anolis sagrei Dumeril & Bibron, 1837 (Squamata, Dactyloidae) taking over Panama City, Panama. Check List 15: 455-459.
Calsbeek, R. and Cox, R. M. 2010. Experimentally assessing the relative importance of predation and competition as agents of selection. Nature 465: 613-616.
Campbell, T. S. and Echternacht, A. C. 2003. Introduced species as moving targets: changes in body sizes of introduced lizards following experimental introductions and historical invasions. Biological Invasions 5: 193-212.
Capinha, C., Seebens, H., Cassey, P., Garcia‐Diaz, P., Lenzner, B., Mang, T., Moser, D., Pysek, P., Rodder, D., Scalera, R. and Winter, M. 2017. Diversity, biogeography and the global flows of alien amphibians and reptiles. Diversity and Distributions 23: 1313-1322.
Donihue, C. M., Kowaleski, A. M., Losos, J. B., Algar, A. C., Baeckens, S., Buchkowski, R. W., Fabre, A. C., Frank, H. K., Geneva, A. J., Reynolds, R. G., Stroud, J. T., Velasco, J. A., Kolbe, J. J., Mahler, D. L. and Herrel, A. 2020. Hurricane effects on Neotropical lizards span geographic and phylogenetic scales. Proceedings of the National Academy of Sciences, USA, 117: 10429-10434.
Echternacht, A. C. 1999. Possible causes for the rapid decline in population density of green anoles, Anolis carolinensis (Sauria: Polychrotidae) following invasion by the brown anole, Anolis sagrei, in the southeastern United States. Anolis Newsletter 5: 22–27.
Fetters, T. L. and Mcglothlin, J. W. 2017. Life histories and invasions: accelerated laying rate and incubation time in an invasive lizard, Anolis sagrei. Biological Journal of the Linnean Society 122: 635-642.
Gerber, G. P. and Echternacht, A. C. 2000. Evidence for asymmetrical intraguild predation between native and introduced Anolis lizards. Oecologia 124: 599–607.
Hsu, M. H., Lin, J. W., Liao, C. P., Hsu, J. Y. and Huang, W. S. 2021. Trans-marine dispersal inferred from the saltwater tolerance of lizards from Taiwan. PLoS One, 16: e0247009.
Jamison, S., Tamar, K., Slavenko, A. and Meiri, S. 2017. Tarentola annularis (Squamata: Phyllodactylidae): a new invasive species in Israel. Salamandra 53: 299-303.
Jensen, J. B., Camp, C. D., Gibbons, W. and Elliot, M. J. 2008. Amphibians and reptiles of Georgia. University of Georgia Press, Athens.
Kamath, A., Herrmann, N. C., Gotanda, K., Shim, K. C., LaFond, J., Cottone, G., Falkner, H., Campbell, T. S. and Stuart, Y. E. 2020. Character displacement in the midst of background evolution in island populations of Anolis lizards: a spatiotemporal perspective. Evolution 74: 2250-2264.
Kraus, F. 2009. Alien reptiles and amphibians. A scientific compendium and analysis. Springer Verlag, Berlin.
Losos, J. B. 2009. Lizards in an evolutionary tree: ecology and adaptive radiation of Anoles. University of California Press, Berkeley.
Losos, J. B. and Pringle, R. M. 2011. Competition, predation and natural selection in island lizards. Nature 475: E1-E2.
Losos, J. B. and Spiller, D. A. 1999. Differential colonization success and assymmetrical interactions between two lizard species. Ecology 80: 252-258.
Losos, J. B., Marks, J. C. and Schoener, T. W. 1993. Habitat use and ecological interactions of an introduced and a native species of Anolis lizard on Grand Cayman, with a review of the outcomes of anole introductions. Oecologia 95: 525-532.
Losos, J. B., Schoener, T. W. and Spiller, D. A. 2004. Predator-induced behaviour shifts and natural selection in field-experimental lizard populations. Nature 432: 505-508.
Meiri, S., Belmaker, A., Berkowic, D., Kazes, K., Maza, E., Bar-Oz, G. and Dor, R. 2019. A checklist of Israeli land vertebrates. Israel Journal of Ecology and Evolution 65: 43-50.
Meiri, S. 2021. The brown anole in Israel, assessing the invasion pathway, establishment potential and potential threats. Report to the chief ecologist, Israel Nature and Parks Authority. In Hebrew.
Norval, G., Huang, S.-C., Mao, J.-J., Goldberg, S. R. and Slater, K. 2012. Additional notes on the diet of Japalura swinhonis (Agamidae) from southwestern Taiwan, with comments about its dietary overlap with the sympatric Anolis sagrei (Polychrotidae). Basic and Applied Herpetology, 26: 87-97.

Perry, G., Powell, R. and Watson, H. 2006. Keeping invasive species off Guana Island, British Virgin Islands. Iguana, 13: 273-277.

Roughgarden, J. 1995. Anolis lizards of the Caribbean: ecology, evolution, and plate tectonics. Oxford University Press, Oxford.
Schoener, T. W., Losos, J. B. and Spiller, D. A. 2005. Island biogeography of populations: an introduced species transforms survival patterns. Science 310: 1807-1809.
Sexton, O. J. and Brown, K. M. 1977. The reproductive cycle of an iguanid lizard Anolis sagrei, from Belize. Journal of Natural History, 11: 241-250.
Solis, J. M., Ayala-Rojas, C. G. and O’Reilly, C. M. 2017. New records for two reptiles from the Bay islands, Honduras. Mesoamerican Herpetology 4: 669-671.
Stroud, J. T., Giery, S. T. and Outerbridge, M. E. 2017. Establishment of Anolis sagrei on Bermuda represents a novel ecological threat to Critically Endangered Bermuda skinks (Plestiodon longirostris). Biological Invasions, 19: 1723-1731.
Stroud, J. T., Mothes, C. C., Beckles, W., Heathcote, R. J., Donihue, C. M. and Losos, J. B. 2020. An extreme cold event leads to community-wide convergence in lower temperature tolerance in a lizard community. Biology Letters, 16: 20200625.
Stuart, Y. E., Campbell, T. S., Hohenlohe, P. A., Reynolds, R. G., Revell, L. J. and Losos, J. B. 2014. Rapid evolution of a native species following invasion by a congener. Science 346: 463-465.
Thawley, C. J. and Kolbe, J. J. 2020. Artificial light at night increases growth and reproductive output in Anolis lizards. Proceedings of the Royal Society of London B. 287: 20191682.

The mainland ground anole Anolis tandai from Brazil. (Photo: Ivan Prates)

From GW Today:

June 02, 2021

By Kristen Mitchell

A George Washington University Columbian College of Arts and Sciences Ph.D. student recently published a paper about the evolution of Central and South American anoles, a group of tropical lizards that have been historically understudied compared to their distant relatives in the Caribbean. The study was a collaboration with researchers from the Smithsonian National Museum of Natural History.

Jonathan Huie, a Ph.D. candidate in the Department of Biological Sciences, got involved in this work as an undergraduate student through a National Science Foundation research internship at the Smithsonian National Museum of Natural History. This research sparked his passion for lizards and ultimately guided him toward a doctoral program studying salamanders at GW.

Mr. Huie is lead author of the new paper, published in The Biological Journal of the Linnean Society on Wednesday. Mr. Huie spoke to GW Today about the impact of this research.

Q: Why has there historically been such a significant gap between what researchers know about Caribbean anoles and what they know about anoles found in Central and South America?
A: Most of the 400-plus species of anoles live in Central and South America, and yet the lion’s share of anole research has focused on Caribbean species. There are likely several reasons why, but ease and accessibility are definitely important factors. In the Caribbean, anoles are quite abundant and easy to find but mainland anoles are more secretive, likely because they have more predators to hide from. It’s difficult to study what you can’t see.

Another reason may be because islands themselves are excellent study systems. They’re small and easier to make sense of compared to mainland systems. There’s also a lot of them, which is ideal for replication and hypothesis testing. Lastly, science is often conducted where it’s easiest or most desirable to establish a field site so it’s probably no coincidence that many well-studied anoles occur near vacation spots.

With that said, there’s been a huge push in recent years to learn more about mainland anoles. Our study wouldn’t have been possible otherwise, but there is still a lot we don’t know about mainland anoles.

Q: What did your research reveal about how anoles in Central and South America have evolved to fill various ecological niches?
A: Anoles originated on the mainland, then they colonized the Caribbean, and eventually re-invaded the mainland. Caribbean anoles are well-known among biologists for repeatedly evolving sets of species with similar ecologies and morphologies on Cuba, Hispaniola, Jamaica and Puerto Rico. For example, some species live on thin perches like twigs and have convergently evolved short limbs and well-developed toe pads. Other species specialize in living in tree-crowns, on tree trunks, grasses and bushes. We found that when anoles diversified on the mainland the second time, they convergently re-evolved all of the same habitat specialists and morphological adaptations found in the Caribbean—but this time in Central and South America. This is fascinating given what we often believe to be true about islands and continents.

Our second main finding was that ground-dwelling anoles are really common on the mainland and have their own set of morphological adaptations. Many Caribbean anoles forage on the ground, but very few live there full-time. Mainland ground anoles, on the other hand, really took off. We hypothesized that ground anoles are common on the mainland—at least among the group that re-invaded the mainland—because most arboreal niches were already occupied by other lizards. It’s unclear why Caribbean ground anoles are not more abundant.

Q: How do your findings challenge long-held assumptions made about evolution on islands compared to mainland habitats?
A: We found that island and mainland anoles are more similar than previously thought. For a long time, it was believed that islands were hotbeds for extreme morphologies and that continents lacked the necessary conditions. In the context of anoles, island species were considered to be unique—that the relationship between habitat and morphology was fundamentally different on islands versus the mainland. However, we found strong evidence that this is not the case.

That is not to say that everything we once thought to be true is now wrong—there are still many differences between island and mainland anoles. However, our research shifts how we should view island and mainland comparisons. Our paper joins other recent studies in suggesting that the mainland is equally good at cultivating morphological diversity as island environments.

Q: How did you get involved in this research, and how did it shape the kind of research you are doing now as a Ph.D. candidate?
A: I got involved as an undergraduate National Science Foundation Research Experiences for Undergraduates (REU) intern at the Smithsonian’s National Museum of Natural History in 2018, under the co-mentorship of Ivan Prates and Kevin de Queiroz. I was a total fish geek and had never studied anoles, but I signed on to investigate the link between habitat and morphology in a handful of mainland anoles.

I measured their body proportions using the museum’s natural history collection but finished quickly. So, we started adding more and more species, and even after the internship was over, I continued to visit other natural history collections to measure even more lizards. The next thing I knew, I had looked at more than 200 species. Natural history collections like the Smithsonian were absolutely critical for this work and fostering my interests beyond fishes.

As a Ph.D. student, I am currently studying salamander limbs to better understand the type of adaptations needed to make the water-to-land transition. The kinds of questions I am interested in for my dissertation are similar to the ones we approached with the anole project. Without my internship, it’s very unlikely that I would have ended up at GW studying salamanders.

Q: How are you planning to build on this research moving forward?
A: There is still so much left to do. In our recent paper, we only published about half of the data I initially collected. We are excited to dive deeper and look at how body size influences patterns of morphological adaptation.

There’s also the other group of mainland anoles that we didn’t look at. I am interested in knowing more about how these other mainland species fit into the puzzle. Did they adapt in a similar manner as the group of mainland anoles we looked at? Or are they doing something different? We would like to know how often evolution repeats itself to produce similar outcomes.

Vaneisa Baksh is an editor, writer and cricket historian for the Trinidad Saturday Express. She’s written two essays on the local lizards and along the way has chided up herpetologists for not responding to the first one. Let’s get to work!

First she writes several weeks ago, in an article entitled “The LIzards Running Up and Down”:

The first time I heard the sound, I thought a bird had flown into the house, although none of my regular feathered folk chirped like that. I searched and searched, remembering how one time a little dove had come in and had been frantically trying to escape while I tried to guide it to the open window in the kitchen. My efforts were just increasing its anxiety and I had to leave it alone to simmer down until it mercifully found its way to freedom.

This time, there was no bird and eventually, as the sound repeated itself, I spotted the culprit. It was a lizard, a gecko, and although we have co-habited in different houses since I was a child, I’d never heard one of the buggers speak. That was a couple years ago, and curious to know if this was a mutation of the creature we called “24-hours” on account of the myth that if it fell on you, it would stay there for an entire day, I went looking for information.

It turned out that these are really house-loving critters. They prefer to be indoors and are harmless, and might even be regarded as useful. I learned that they feed on insects, cockroaches, termites, wasps, flies, spiders, moths and poor butterflies. I’d decided that I would just have to get used to the unusual sound—the most apt description on Wikipedia was “tchak tchak tchak”, which it said was often sounded six to nine times in sequence. I have a way of seeing words in shapes, and maybe sounds as well. Every time I hear the gecko chirp, I would see the sound like a fairly squared-off pellet. Perhaps it is because the sounds are evenly pitched and last for roughly the same length of time. I don’t know, but I have tried to get used to it suddenly rapping into my consciousness.

At first, it was restricted to my bedroom and my study, but now it seems the lizards are everywhere. Whereas I found it an occasional interruption, now I feel there are colonies of them living in my house and even though I hardly see more than one at a time, I feel that they have taken over.

It is one thing to adjust to the sound they make—tchak tchak tchak is far more bearable than the abrasively loud grinding from the welding next door—but these discreet urban dwellers leave their little droppings everywhere. Everywhere. Not only do I have to clean them off the floors, especially at the base of the walls, but the area that really trips me is by my bedside table and on my bed. Yesterday, I washed my sheets and replaced them. As I prepared to turn in last night, I spotted the droppings on the edge of the bed. I suppose that’s why I am bringing them up now.

I would dearly like to know if other householders are experiencing this increased presence that is now forcing a whole different level of housekeeping. I have been getting faint whiffs of urine as well, and it drives me crazy, because I am washing cushion covers, curtains, sheets, everything that could be contaminated, and mopping the floors far too often.

It’s not just being finicky, which I am, but for some time now, my eyes have been unusually sensitive and gritty. While it is true that I am spending a considerable amount of time reading and writing in front of various screens, and that the presence of Saharan dust has been exacerbating things, my ophthalmologist says there is evidence of some kind of persistent irritant, or allergy affecting my eyes.

Naturally, I am mindful that it is possible that the creatures overhead who seem to like my bedroom might be doing numbers over my bed and that might be messing with my eyes. I am not trying to gross anyone out, it just seems that it is likely that there is a growing population of the lizards, which I think we also call woodslaves, and that while we might be adjusting to their presence and their noises, we might not be aware of the side effects.

I’ve never had a problem with lizards. When we were children, the whole brood of about 15 to 20 cousins on any given night would gather in my grandfather’s living room to look at television shows because nobody else had a TV.

We’d start streaming in when the news programme, Panorama, began at seven o’clock. That was when he would turn on the black and white beauty with the wooden cabinetry. Afterwards when some other show began (the real reason we were there), he would sit there with us, and if there was any sign of anything remotely inappropriate for us, like a kissing scene, he would suddenly exclaim, “Look, look, look, the lizard up there!” Naturally, we would all momentarily turn our heads away from the screen at the unexpected shout. Sometimes there was a lizard, but more often not, and he would say, “Ah, he run away!” But his distraction worked well enough, or so he thought.

Harmless enough.

But I feel something has changed. There are more, they are loud and though they love being indoors, they are not house-trained! This might sound creepy though I say it in jest, what if I am now the interloper in the house of the lizards?

—Vaneisa Baksh is an editor, writer and cricket historian.

E-mail: vaneisabaksh@gmail.com

 

And then Vanessa writes yesterday in “Welcome to the Lounge of Lizards”:

I’D hoped that bringing up the ungovernable appearance of house lizards might have elicited a response from a couple of herpetologists. Disappointingly none came; but many people shared their experiences and theories. There was much to learn from these personal stories, and they broadened my sense of community, so I want to share some titbits from a few.

I mean, here we are, locked down in our separate cubicles, not knowing anything about one another, and suddenly, we are sharing lizard tales, revealing snippets of our lives that tell us something about daily trials we have in common. It’s not something we’d chat about, and noticing that our traditionally unobtrusive house mates have become loquacious would hardly qualify as a subject for conversation—unless you have physical visitors and the lizards are contributing their five cents to the discussions. Innocuous things have to force themselves unto your radar—usually by causing some disruption—before they register on your consciousness. Like the jiggly latch on a window that you notice every time you open or close it, but never outside that moment.

Curious if these chirpy critters were mutants or had just been imported, I read of work done by Jonathan Losos, a professor of evolutionary biology and a herpetologist, whose research is mostly concerned with how lizards interact with their environment and how they have diversified. Apparently they have focused on the “evolutionary radiation” of Caribbean Anolis lizards, among others, but they are also looking at how species are adapting to urban environments.

One related study examined the impact of an invasive anole species in Dominica. Up until two decades ago, it was home to a single species until a second species arrived tucked inside a shipment of lumber. Not hard to imagine our lizards coming in by sea. I remember landing in Nevis on one of those small aircraft and as we disembarked, a scorpion scurried down the aisle as soon as the door was opened. Naturally, ­passengers let the hustler disembark first.

A 65-year-old reader sent this: “Our first house was a small ‘board-house’ with a thatched roof and termite-ridden boards. I could knock on a board to find out if it was termite-eaten by the hollow sound that emanated. Prying into the thin cover, I would find the hollow cavities. Here the house-geckos laid their eggs. Unfortunately, sometimes I would remove the eggs. The old Indian people used to call them ‘bistooyas’, the ones about three inches long, sometimes with white stripes from their eyebrows to the body.”

Quite a few people said they had been hearing the noises but couldn’t figure out the source, assuming it was some kind of night bird, and some thought they were alone in this experience.

One person said that around the same time they began hearing those sounds they noticed that “my eyes felt like I had nits in the base of my eyelashes, and the attendant discomfort… At the same time, I had noticed a reduction in small spiders, spider’s webs, and mosquitoes”.

A woman of the West included a delightful description of the upsurge of geckos. “There’s quite a lot of courtship going on between pairs, appropriately, in our bedroom, and each pair seems to play tag, with a pursuer and its quarry. Inevitably, though, they come to an agreement and tiny baby lizards pop up soon after.” She doesn’t mind them, she says, but most of the women harbour strong feelings.

“I detest those creatures. They are annoying. They feed on the insects in the house. If by chance I should see one within easy reach, I implore my husband to get rid of it, and he would hold it using a piece of cloth and throw it outside. He doesn’t harm them,” said one.

A few mentioned that peppermint infused with water makes a reasonable repellent. One had specific directions: peppermint oil may be used by soaking cotton balls and placing them on the top of shelves, inside closets, behind books and similar places. I prefer using a spray bottle, measuring half water and quarter oil and spraying in the same places. It’s been keeping them away so far and the smell becomes less pungent after a few days.” Another said she had tried it, but is worried about the larger implications.

“There is something amiss in the ecosystem. This, what can only be described as an infestation, is a new phenomenon. Is this a new and invasive species or has this lizard been blessed by depleting stock of its natural predators? I do think it is something which the scientists need to investigate. Is there something more sinister at work? And what are the implications? I have always been leery of lizards. Their presence disconcerts me. And now this is like living in some kind of mild horror story—in my own house! Lizards pop up everywhere—in the vegetable basket, in the clean-clothes basket, drop from the roof. One found its way into my glass of water; fortunately, I looked down before I sipped!”

Another said, “I agree with you totally on all that you said, and I believe that these creatures are being used for sinister purposes.”

I don’t know about that, but I enjoyed learning more, like discovering that a group of lizards is called a lounge. I imagine them lounging about our homes and I figure what better place for a lizard to lime than this country!

From the Tuscaloosa News:

One of the most commonly seen lizards in the Southern states is the green anole, also known as North American green anole or Carolina anole. (Its scientific name is Anolis carolinensis.) Although more than 400 species of anoles are known to science, the green anole is the only one native to the United States. Most people appreciate seeing them in their yards.

Q. A type of lizard we have in Birmingham, Alabama, is sometimes green and sometimes brown. I know it is not two different kinds of lizard because I have watched one change from brown to green. Are these a type of chameleon that can change skin color to match their surroundings?

A. No. Anoles are in a different family of lizards from Old World chameleons. Those are the ones famous for being able to change skin color based on the background, thus creating a true camouflage. In green anoles, color change is a response to external factors, such as temperature and humidity. It may also be influenced by hormonal changes. Whether lizards experience emotions comparable to humans remains a mystery. Researchers continue to investigate why anoles change color, as well as what purpose that change serves for the individual lizard. Most anoles found hidden under bark or leaves on cool days will be brown. If you pick up a brown one and hold it, it will usually turn green.

To learn more, I contacted Tom Jenssen, an expert on the subject of color-changing behavior in green anoles. During his career as a professor at Virginia Tech, Jenssen observed thousands of green anoles while conducting research on the species.

His observations confirmed categorically that the color of a green anole has nothing to do with what the lizard is standing on. One on a green leaf can be brown; one on dark soil can be green. He indicated that factors causing a green anole to exhibit the brown color phase are not completely understood, but he explained the biological mechanism:  “Color-shifting comes from melanophore activity over a sub-dermal layer whose structure reflects green wave lengths.”

In other words, the concentration of black or brown pigment cells determines the color exhibited. If the pigment cells are large, they obscure a lower level in the skin that reflects green light. When the cells are concentrated, the lizard looks dark brown, mottled brown or even like a bad bruise of blotchy brown and olive-green. If the pigment cells contract in size, the lower level is exposed, and the lizard appears green.

He further noted that the activity of pigment cells and their concentration are controlled by the endocrine system, the glands that affect hormones and mood changes for many animals.

The remaining biological mystery: What triggers the endocrine system to cause the pigment cells to contract or expand? Body color in anoles is highly complex with no simple answer for why an individual is a particular color at any given time. Social interactions with other lizards may be responsible in some cases. Brown coloration could possibly result in faster warming of the body on a cool sunny day.

Q. Why do these lizards that can change from brown to green sometimes have a bright red throat?

A. Male green anoles use the vivid red throat fan, or dewlap, to challenge other male anoles and sometimes even other animals. The dewlap display is often accompanied by push-ups and head-bobbing. An invasive species from Cuba, the brown anole, now found in Florida, Georgia and Alabama, has an orange dewlap. Next time you see a green anole displaying a red throat, take a moment to watch its performance. Who is its audience? Is it another anole in the vicinity — or is it you?

Native green anoles are completely harmless and offer fun outdoor entertainment. Enjoy watching them stalk bugs and interact with each other. They are indicative of a healthy environment and deserve our appreciation wherever we find them.

Whit Gibbons is professor of zoology and senior biologist at the University of Georgia’s Savannah River Ecology Laboratory. If you have an environmental question or comment, e-mail ecoviews@srel.edu.

Charles Leeper shows us a green anole in action from around his home. And here’s an oldie of Anolis smaragdinus doing the same: