AA reader Diane Hickey Davis asks: Are there any differences, genetic or otherwise, between the Green Anole (Anolis carolinensis) found wild in Louisiana, Alabama, Florida panhandle, Tampa region, and those sold by Carolina Biological supply or PetSmart?
I have an observation of the Green Anole (Anolis carolinensis) from the southern Cumberland Plateau of Tennessee. A population of these anoles lives on a south facing rock outcrop at the top of the plateau. In November 2017, I saw an individual with what appeared to have multiple hair-like features on its head. I first located this population in March 2017. Of the individuals I photographed in March 2017, neither showed evidence of these hair like features. I have been unable to locate any individuals from this population in two trips to the site in 2018.
Any thoughts on what this hair-like feature might be? Has anyone else observed this in Anolis carolinensis or any other anole species?
Dear anolologists,
The 31st July deadline for submissions to the Anolis newsletter is fast approaching, and we want to remind everyone that this is an open submission for all contributions!
See this previous post for all information you need on the type of contributions we are looking for!
We particularly encourage all of those anolologists who presented research at the 2018 Anolis Symposium to contribute brief synopses of their talks or posters.
Best wishes
The AN Editorial Team
Submit contributions to: anolis2018@gmail.com
Formatting instructions: http://www.jameststroud.com/uploads/2/6/1/3/26134722/anvii_formatting_instructions.pdf
A brown anole emerging from the egg.
There is much talk these days about how human land use (e.g. urbanization) impacts wildlife. Although anoles have often taken center stage in this discussion (Winchell et al. 2016; Tyler et al. 2016; Chejanovski et al. 2017; Lapiedra et al. 2017; Winchell et al. 2018), most of this work has focused on measuring phenotypes of adult males. Very little work has been done to understand how massive habitat alteration impacts early life stages even though we know that these stages are extremely sensitive to environmental disturbance and have the potential to impact population dynamics (Carlo et al 2018). Embryos are particularly sensitive to changes in the environment because they lack the ability to respond to unfavorable conditions by adjusting their behavior (i.e., they can’t run away). Since the 1980’s, we’ve known that egg mortality can have massive effects on population densities and even determine how these densities cycle from year to year (Andrews 1982; Andrews 1988; Chalcraft and Andrews 1999). Still, comparatively little attention is given to embryo development and egg survival when considering how habitat alteration impacts species.
In a newly published paper (Hall & Warner 2018), we sought to understand how extreme ground temperatures in cities and suburbs (i.e., the urban heat island effect) influence patterns of embryo development. Due to a lack of canopy cover (i.e., trees) and an abundance of heat-absorbing surfaces (e.g., concrete), cities and suburbs tend to be much warmer than adjacent forested areas, and this means nest temperatures are higher in urban and suburban areas compared to adjacent forested sites (Tiatragul et al. 2017). Warm temperatures often have positive effects on embryo development; however, extremely warm temperatures can cause mortality and even slow developmental rates (Sanger et al. 2018).
Figure 1. An overview of our experimental design to understand how urban incubation regimes impact embryo development and survival. Eggs from both forest and city populations were factorially distributed into forest and city incubation treatments. At approximately a quarter of the way through development, some eggs were exposed to a spike in temperature measured from the field (either 39 or 43 °C peak). Eggs completed development at their assigned incubation profile (city vs. forest) and hatchling growth and survival were monitored in the lab for three months.
While performing population research of Anolis (Norops) bicaorum at Kanahau Utila Research & Conservation Facility, we stumbled upon two males in close proximity initiating a territorial dispute. With the intention of documenting this behavior, we began to record the interaction.
In all honesty, the confrontation was a little shorter than any of us expected… It may well be one of my funniest fieldwork memories to date (despite watching it on repeat, I still can’t help but chuckle at this anole’s misfortune!) . To detail, upon the first exchange of dewlap extensions, the responding male slipped and fell clumsily from the trunk; meanwhile, his contender (who was in the process of displaying) looked on, apparently baffled at the sudden disappearance of his rival.
It appears the falling males mistake arose owing to a combination of two factors. The simple explanation is that this male lost his footing on the steep vertical trunk (which formed the battleground on this occasion), but indeed it’s rare to see an anole make such an error of judgement; the lamellae on their feet afford them excellent grip on many substrates. The second explanation owes to the fact males are completely intolerant of one another. We noted that when engaging in territorial disputes, males of A. bicaorum become entirely absorbed in their confrontation, possessed by their territorial natures and relentless in their efforts to dissuade and expel contenders from their patch. Often, competing individuals become so preoccupied that hey no longer perceive apparent dangers (e.g., the closely observing biologists). Perhaps the haphazard approach of males in territorial engagement leaves them prone to the occasional miscalculation.
If you are curious to learn more about Anolis (Norops) bicaorum (a threatened species endemic to Isla de Utila, Honduras), the most recent research by Brown et al. (2017) at Kanahau URCF resulted in published records on their geographic distribution, natural history, ecology and interactions with sympatric anoles.
From the Herping in Cuba Facebook page (with permission).
The Bark Anole (Anolis distichus ignigularis) from the Río Recodo. Photo from Richard Glor’s Flickr.
The Bark Anole (Anolis distichus) is a highly polymorphic lizard widely distributed in Hispaniola. Anolis distichus is divided into 16 subspecies with dewlap colors ranging from deep wine red to pale yellow (Glor and Laport 2012). In the early days scientists, such as Albert Schwartz, argued that A. distichus is divisible into multiple subspecies according to an analysis of variation in body color and dewlap pigmentation. But, are they really subspecies?
During the 2018 Joint Meeting of Ichthyologists and Herpetologists (JMIH), Richard Glor shared his lab’s advances on the curious case of Bark Anoles. Anolis distichus populations have ecological, phenotypic and genetic differences. Previous studies show a correlation between dewlap phenotype and environmental variation; in drier habitats, lizards have smaller, brighter, yellow dewlaps, while those in wetter habitats have larger, less bright, orange dewlaps (Ng et al. 2012).
Previously, the Glor Lab found strong support for the hypothesis that A. distichus is comprised of numerous genomically distinct populations (MacGuigan et al. 2016). Genetic divergence was associated with a biogeographic barrier, but not with dewlap color. Also, they found evidence for hybridization in contact zones with limited gene flow and intrinsic reproductive isolation between subspecies (MacGuigan et al. 2016; Ng et al. 2016). Overall, these studies suggest that geographic isolation, as well as ecological specialization, contribute to speciation.
The Glor Lab continues putting together the pieces of the puzzle. Most recently, they sequenced and assembled whole genome sequence data for A. distichus to identify the genomic basis for species differences and speciation.
Crested Anole (Anolis cristatellus) under a leaf. Photo by Chris Thawley.
Conservation biologists have long been concerned about the effects of human development on species and environments. Urban habitats can significantly change lighting patterns for animals by increasing nocturnal ambient illumination. Artificial light at night (ALAN) has the potential to disrupt an organism’s physiology, behavior, and ecology. However, light pollution remains poorly studied and is a concern for urban herpetofauna.
Anolis lizards in Miami, Florida are a great system to study the effects of ALAN on behavior, health, reproduction, and survival. Anoles are diurnal and are adapted to a distinct photic habitat appropriate to their sun/shade preferences. However, many anole species have been observed active at night where artificial lights are prevalent. So, what are the effects of ALAN on anole fitness?
Chris Thawley, a postdoctoral researcher in the Kolbe Lab at the University of Rhode Island, is interested in whether ALAN imposes selection on anoles and how they might adapt to these pressures. Chris conducted a field experiment introducing landscape lightning into a previously unlighted habitat within an urban matrix. For over two months, he assessed whether Brown Anoles (Anolis sagrei) and Crested Anoles (A. cristatellus) experienced higher levels of ALAN at their sleeping perches and if these lizards behaviorally avoided exposure to artificial light. Also, lizards were marked and followed to determine if light exposure impacted survival, growth, body condition, and physiology.
Chris found that A. sagrei and A. cristatellus lizards are not behaviorally avoiding ALAN at night. Anoles that were more exposed to artificial light had lower glucose levels compared to those that were less exposed. Also, there were no dramatic changes in reproduction, but ALAN reduced follicle size. Egg mass showed a positive relationship with snout-vent length (SVL) in lizards exposed to ALAN, which suggests that ALAN increases egg mass in larger lizards. Chris continues analyzing growth and survival data and aims to explore if there is a correlation between levels of corticosterone (CORT), melatonin, and glucose.
A brown anole (Anolis sagrei) surveys its domain.
Trophic ecology deals with questions about the ways in which organisms acquire energy and how that process interacts with the communities and ecosystems surrounding them. Anole-focused research has played a strong role in our understanding of trophic ecology and ideas abut how communities come together and evolve, particularly in papers by Schoener, Roughgarden, and Lister. However, many trophic ecology studies have focused on specific communities or locations and haven’t dealt with how the ecology of one focal species varies across space and as a function of the presence of other close competitors.
Sean Giery, a post-doc at the University of Connecticut, in collaboration with James Stroud, a post-doc at Washington University in St. Louis, worked to address this gap in our knowledge by studying how the trophic ecology of the brown anole, Anolis sagrei, varies across its range. Brown anoles are voracious predators of insects, known to chow down on a diverse range of arthropods, including some of surprising size. Since the brown anole is also a prodigious invader, it occupies habitats with a variety of potential competitors, including locations with few competitors. Sean and James leveraged this situation to their advantage by compiling stomach content data from previously published papers (including a follow-up on Lister’s paper above). They also added their own sampling, including in Southern Florida, the Bahamas, and Hawaii…tough work! Sean and James then used the articles themselves, field guides, and citizen science sources like iNaturalist to determine the presence of other species which might compete with the brown anole, including other anoles and diurnal, insectivorous lizards.
Sean and James assembled an impressive database of the diet of A. sagrei.
They found that as community richness increases, the dietary niche of A. sagrei actually becomes broader, the opposite of the direction predicted by theories of ecological release. Additionally, average niche overlap between individual anoles declines as community richness increases. When only brown anoles are present in a community, individuals are highly similar in the types and proportions of what they eat, another finding which runs counter to models of how niche breadth should vary when a species is released from interspecific competition. Sean concluded his talk by suggesting that interference competition may be more important than generally recognized and soliciting suggestions for ways to continue looking at this impressive dataset. We’ll look forward to reading the paper!
Spencer Asperilla presenting his poster, “A Biodiversity Survey of Parasites from Anolis Lizards on Andros Island, Bahamas”, at the 2018 Joint Meeting of Ichthyologists and Herpetologists (JMIH).
Anolis species inhabiting the Caribbean provide a great example of adaptive radiation and convergent evolution in ecology, morphology, and behavior. Adaptation, diversification, and specialization to a particular microhabitat and dietary resource, created a great diversity among anoles. But what about their parasite assemblages? Andros Island in the Bahamas is the fifth largest island in the Caribbean Archipelago. However, it is still unclear if the parasite fauna hosted by Anolis lizards show similar evolutionary pathways.
In 2016, after an amazing experience studying abroad at ForFar Field Station on Andros Island, Spencer Asperilla and Katie Brittain joined the Langford Lab at Florida Southern College. Spencer and Katie were interested in documenting parasite species present in Bahamian Anolis lizards to determine if these are specialists or generalists among ecomorphs and identify if parasite populations vary seasonally. They conducted parasite biodiversity surveys on three sites on Andros Island, which involved capturing lizards and collecting blood smears and fecal matter. Specimens and samples were transported to Florida Southern College where they were processed and analyzed for parasites.
Spencer and collaborators found that parasitic infection rate was highest during the Summer (66.66%), and lowest during the Spring (60.56%); however these differences were not significant. Climate variables, such as mean daily temperature and precipitation, were evaluated, but no seasonal pattern could be determined for parasite infections in Bahamian lizards. As for parasite diversity, Brown Anole (Anolis sagrei; trunk-ground ecomorph) lizards had most species of parasites present, while A. angusticeps (twig ecomorph), A. distichus (Bark Anole; trunk ecomorph), and A. smaragdinus (Green Anole; trunk-crown ecomorph) had lower species diversity. The authors suggest these differences are related to the biology of the different ecomorphs. Trunk-ground anoles, such as A. sagrei, might be more susceptible to parasite infection by descending to the ground to capture prey or interact with a conspecific, whereas the other ecomorphs remain higher up in the tree. Ground-dwelling insects may serve as intermediate hosts for parasites found in trunk-ground anoles. Spencer and collaborators propose that habitat use, as well as dietary composition, serve as an ecological explanation for parasite distribution among ecomorphs.
The big question remains unanswered: have parasite species coevolved with specific lizard hosts? The Langford Lab continues identifying parasites species to assess the diversity, host-specificity and infection patterns of Bahamian Anolis lizards. Spencer wants to resume this project as part of his master’s thesis and he looks forward to traveling back to Andros Island to collect additional samples.
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