Hey there!
I’ve been wanting to do this anole for a while so I’m kind of excited. These posts keep me going sometimes when the news is rough. I hope anoles bring you some respite as well.
Anolis agassizi is an anole that is endemic to Malpelo Island (off the coast of Colombia).
The island has rocky terrain and no vegetation, and the anoles are not territorial, and will willingly overlap or share perches and food sources. The insects that they eat are mainly beetles that are attracted to the colonies of birds that nest there. They also seem to have an attraction to the colour orange.
Anolis agassizi males have an average SVL of 105.4 mm, and females at 85.2 mm. They are mainly predated on by the Malpelo (or Dotted) galliwasp and seabirds.
Large males have large nuchal crests that are permanently erect, unlike other anoles. The small morphs of the male anoles also differ in colour, having spotted heads like the females do. All males have very small dewlaps.
Anolis marmoratus, by Kristin Winchell. This photo is featured in the Anole Annals 2021 calendar!
Last year, Rafael Alejandro Lara Resendiz (Centro de Investigaciones Biológicas del Noroeste and Instituto de Diversidad y Ecología Animal) published a paper in Acta Biológica Colombiana, in which he summarizes nocturnal activities in exclusively diurnal reptiles and addresses the question of how this behavior affects their ecophysiology.
Ectotherms – reptiles, amphibians, fish, and most invertebrates – need environmental temperature to produce heat internally, meaning that these organisms depend upon an external source of heat to regulate their internal functions. Thermoregulation is a complex physiological process that is involved in every activity that allows ectotherms to survive in nature (e.g., feeding and reproductive behavior, growth patterns, locomotion, digestion). In this regard, ectotherm species differ in their thermoregulation behaviors; some species are more active during the day while others are active during the twilight. However, some species that are known to be diurnal have been found active during the twilight. Lara-Resendiz (2020) address four-point in his work. Specifically, he 1) reviews nocturnal activity events in reptiles considered exclusively diurnal; 2) discusses the ecophysiological implications on this topic; 3) identifies the aspects that have not yet been approached in-depth; and 4) proposes possible directions for future lines of research.
Several species that are known to be exclusively diurnal have been observed carrying out nighttime activities, including lizards (e.g., Agama, Anolis, Callisaurus, Dipsosaurus, Gerrhonotus, Liolaemus, Ophisaurus, Phrynosoma), snakes (e.g., Charina, Contia, Masticophis), tortoises (e.g., Gopherus, Geochelone), marine turtles (e.g., Chelonia). Particularly, reptiles inhabit a wide variety of habitats including tropical and cold areas, desserts, high and low elevation areas, and the sea. Living in this different environment may cause lizards to have different patterns of activities throughout the daytime or nighttime: geographical location and thermal environmental variability have a tight relationship with the period of activities of all ectotherms.
One hypothesis has been proposed to explain the nocturnal behavior in diurnal species, in which ectotherm species have different optimal temperatures in the photophase (daytime) and scotophase (nighttime). In this regard, by selecting different environmental temperatures during each phase species that are active during the day can also be active during the night. In some other cases, species that are known to be strictly diurnal can behave opportunistically during the night due to ecological or physiological conditions – high levels of humidity and/or low predation rate, and prey can be easily spotted. Another possible explanation of this change in the time of activity in lizards and snakes is the heterogeneity or homogeneity in the temperature variation in the environment, where species that inhabit stable habitats cannot increase the length of their foraging time, while those species in more heterogenous habitats have more opportunities to extend their activity period due to their wide-body temperature range; this hypothesis has not been tested yet.
Currently, ectotherm species are facing the consequences of the change in the global temperature because they depend on the temperature of their habitat. Climate change is causing species to overheat, therefore, changing their diurnal activity and increasing vulnerability in their population structure. Particularly, these effects have been stronger in the atropical ectotherms which are inhabiting places where the temperature is near their optimal temperature. This suggests that the nocturnal opportunistic behavior of some ectotherm species could be a response to the increasing temperatures.
In conclusion, we need to address questions regarding why these changes in the foraging activity of ectotherm is occurring, and how their ecology and physiology is or could be affected by foraging during the nighttime.
Abstract:
This review is the first to summarize published studies that document nocturnal activity events in reptiles previously considered exclusively diurnal. The ecophysiological implications of this nocturnal activity in tropical and high-latitude environments are described and discussed from the perspective of optimal activity temperature ranges, tolerance thresholds, activity periods, cathemerality, voluntary hypothermia, and its importance in the face of global climate change. Gaps in the research field are finally identified, and new lines of study are proposed.
Urban invaders are not bold risk-takers: a study of 3 invasive lizards in Southern California
In Current Zoology
Putman, Pauly, and Blumstein
Abstract
Biological invasions threaten biodiversity worldwide, and therefore, understanding the traits of successful invaders could mitigate their spread. Many commonly invasive species do well in disturbed habitats, such as urban environments, and their abilities to effectively respond to disturbances could contribute to their invasiveness. Yet, there are noninvasive species that also do well in disturbed habitats. The question remains whether urban invaders behave differently in urban environments than noninvaders, which could suggest an “urban-exploiting” phenotype. In Southern California, the co-occurrence of invasive Italian wall lizards Podarcis siculus, brown anoles Anolis sagrei, and green anoles A. carolinensis, and native western fence lizards Sceloporus occidentalis offers an opportunity to test whether invasives exhibit consistent differences in risk-taking within human-altered habitats compared with a native species. We predicted that invasive lizards would exhibit more bold behavior by having shorter flight-initiation distances (FIDs) and by being found farther from a refuge (behaviors that would presumably maximize foraging in low-risk environments). Invasive populations had similar or longer FIDs, but were consistently found at distances closer to a refuge. Collectively, invasive lizards in urban habitats were not bolder than a native species. Reliance on nearby refuges might help species successfully invade urban habitats, and if a general pattern, may pose an added challenge in detecting or eliminating them.
I know this year has been off to… a start.
A lot has happened, and while someone else would avoid “getting political” in their scicomm, I think we should acknowledge that science is political. Voting was only one step to making America better, and that was threatened by people who want to continue to perpetuate racism and white supremacy. We all saw what happened. There’s no way that anyone calling the people who stormed a government building during an election process are patriots. There’s so much work to do, more than reading a book or following more Black scientists on social media. While those are good, being anti-racist and standing up against people who would seek to uphold these structures are continuous processes. I hope this new year brings you renewed resolve to be allies.
Now. Here’s to a good anole to start the year with.
Anolis bartschi, also known as the Western Cliff anole and West Cuban anole, is beautiful and peculiar.
Found in the Pinar del Rio, the westernmost province of Cuba, this anole lives on karstic (a type of limestone topography) hills, equipped with long hindlimbs and toes that help it get around the terrain. It can be found on the rock faces, cliffs, rock piles and in crevices.
It is one of two (known) anoles that completely lack a dewlap, but it does inflate its throat as a display, along with the usual anole head bobs. They are also one of the few species with communal nests, with the females laying their eggs in crevices on the sides and walls of caves. Female Western Cliff anoles can get up to 6.4 cm long (SVL) and the males about 7.5cm. They are also one of the few anoles with blue colouring.
Checking another box for uncommon anole behaviour, Western Cliff anoles squeak (Rodríguez Schettino et al.,1999)! And they may hang from their forelimbs, and walk with their toes raised. An individual may eat smaller anoles than themselves.
Western Cliff anoles are considered at a low extinction risk.
Like many anoles, we are still learning about more this anole and I can’t wait to find out more.
Exercise has many effects on your body, most of which are good, and is why we humans do it to stay healthy. However, some of those changes, especially under very intense regimens, can have unseen consequences that might be bad. Your immune system, for example, responds to different types of exercise (aerobic endurance versus anaerobic resistance) by altering which branch of your immune system is dominant at that time. Both kinds of exercise tend to increase the more specific ‘humoral immunity’ (B-cell immunity below) over the more general ‘cell-mediated immunity (T-cell immunity below), though the routes to get there are very different for the two kinds of exercise. However, most of what we know about exercise-immunity tradeoffs is from humans and rodents. What about in other animals that have limited access to resources? Might simple energy limitation cause overall immunity suppression when energy is diverted to athletic performance?
My former student Andrew Wang and I studied this experimentally with green anoles. We trained lizards for endurance on a treadmill, or for resistance with weights on a racetrack, for 9 weeks, and compared those to a sedentary control group. Both of these types of locomotion are important to anoles in the wild, and the training schedule was meant to simulate the high end of movement patterns in nature. We then subjected them to three immune challenges: (1) swelling response to phytohemagglutinin (cell-mediated immunity), (2) antibody response to sheep red blood cells (humoral immunity), and (3) wound healing ability (integrated response across all parts). We expected that if simple energy limitation explained tradeoffs, all immune measures would decrease, with endurance-trained suffering the most. If protein limitation was the reason for tradeoffs, then we expected all immune measures to decrease, with sprint-trained suffering the worst. Finally, if the response is due to changes in molecular pathways specific to type of exercise, we expected humoral immunity to be favored over cell-mediated in both trained groups.
Figure 1 from Wang and Husak (2020)
Our results did not support only one of our hypotheses. Endurance-trained lizards had the lowest cell-mediated immunity, whereas sprint-trained had the lowest wound healing ability. Antibody production did not differ among treatments. Our hypothesis of sprint-trained lizards (or even endurance-trained) having the lowest overall immune function was not supported, suggesting that energy limitation alone does not explain immune system alteration. For sprint-trained lizards, energy was likely important, since wound healing, an expensive task, went down the most in that group. For endurance-trained lizards, though, the change in T helper cell production favored humoral over cell-mediated immunity. Since both types of exercise favor humoral immunity, it was not too surprising that antibody production did not differ among treatments. Lots of questions remain to be answered, though!
What does this all mean? In nature, individuals vary dramatically in how much, and for how long, they move around their environment. Those that are more active, thus likely have different immune capabilities compared to more sedentary individuals. It would be very interesting to see how natural variation in survival strategies, high-performance versus high-immunity, affected success in nature. This is a wide-open field for anoles and other reptiles!
Source: Wang, A. Z. and J. F. Husak. 2020. Endurance and sprint training affect immune function differently in green anole lizards (Anolis carolinensis). Journal of Experimental Biology223: jeb232132.
I am a West Indian amateur herpetologist and member of the AA family for the past 5-6 years.
I have travelled and photo-documented anole species along the Eastern Caribbean archipelago from Curaçao in the south to Anguilla in the north. In so doing, the colour patterns of each endemic species have instilled a special thrill to my senses.
However, it is in my home island of Trinidad where a unique spectacle lays in wait of thoughtful analysis. In the urban areas of Port-of-Spain (especially in the suburb of Woodbrook), Anolis aeneus is common on fruit trees, running along house walls and even venturing through windows into home interiors, displaying their speckled glory.
Yet a mere 60 miles to the northeast in the rural village of Fishing Pond (my home village), the anole species A. planiceps rules unchallenged, without the presence of A. aeneus. However, the sighting of A. planiceps is as rare as hen’s teeth (to use a local saying), running along the ground to mount the nearest tree trunk when seen occasionally.
Instead, along my house walls (in that rural area), three lizard species predominate: Ameiva atrigularis and Cnemidophorus lemniscatus, both teiid ground dwellers, as well as Gonatodes vittatus, a gekkonid tree/wall climber. Occasionally, three other species can be seen: Polychrus marmoratus and Tropidurus plica, in the same family as anoles, as well as Mabuya bistrata, a skink in the Scincidae family. The last three are known to be tree/wall climbers. None of these six species are likely to be seen in the urban areas previously mentioned, where household cats and early morning birds seem not to deter the presence of A. aeneus.
My question, therefore: does interspecific competition for food and habitat (and maybe predation) from the other six rural lizard species keep A. planiceps from having larger populations? No other Eastern Caribbean island seems to harbour such an anomaly, except maybe St.Vincent with its elusive A. griseus which is in an environment with few other lizard species.
I await the views of the more learned and experienced members of the AA family.
In closing I’m aware that A. aeneus‘ home base extends to Grenada and the Grenadine Islands, while A. planiceps‘ base extends to Venezuela and Guyana.
I hope you’ve been having a great holiday and that 2021 will be a great year for you. And what better way to end the year than with an anole?
Anolis homolechis, the Cuban White-fanned or Habana anole, is a trunk-ground anole native to Cuba. It is very similar in appearance to the Brown anole (Anolis sagrei), but, as the name suggests, has a stark white dewlap that may have light grey large stripes.
White-fanned anoles are sympatric with Brown anoles; however they partition by temperature, with Brown anoles preferring hotter areas. White-fanned anoles can be found in the shade and can occur at higher elevations than Brown anoles as well (Lizards in an Evolutionary Tree, 2009).
Female Habana anoles have a very small dewlap, almost identical to the males, but with smaller, darker striping.
A recent study published in Biotropica by Beard et al. (2020) examines the impact of removing anoles (Anolis gundlachi, specifically) and perhaps the Caribbean’s most iconic frog, the coquí (Eleutherodactylus coqui), on arthropod densities.
Lizard and frog removal increases spider abundance, but does not cascade to increase herbivory.
Beard, K. H., Durham, S. L., Willig, M. R., & Zimmerman, J. K.
Abstract:
Insectivorous vertebrates, especially on islands, can exert top-down control on herbivorous prey, which can transfer through a food chain to reduce herbivory. However, in many systems insectivorous vertebrates feed on more than one trophic level, especially consuming arthropod predators, and this intraguild predation can diminish trophic cascades. Our goal was to determine, using an exclosure experiment, the relative importance of anole lizards and coqui frogs in controlling spider and arthropod abundances as well as herbivory rates in the understory of the Luquillo Experimental Forest, Puerto Rico. We found that exclosures removing both anoles and coquis doubled spider abundance compared to exclosures with anoles and coquis at natural densities. The effect of coquis on spiders was greater and occurred more quickly than that of anoles, potentially because of the higher natural densities of coquis and removal of both vertebrates produced no interactive effects. We found support for the idea that anoles, but not coquis, reduce foliar arthropod abundances on one of the two studied plant species. However, there was also evidence that anole removal decreased herbivory, the opposite of what we would expect if there was a trophic cascade. Potential explanations include that anoles reduced predatory arthropods on foliage more than they reduced herbivorous arthropods. Results highlight that the food web in tabonuco forest is not simple and that there are complex and dynamic relationships among vertebrate insectivores, predatory arthropods, and herbivorous arthropods that do not consistently result in a trophic cascade.
