Hurricane Effects on Neotropical Lizards Span Geographic and Phylogenetic Scales

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On April 29, 2020

In New Lit Abstracts

New literature alert!

In PNAS
Donihue, Kowaleski, Losos, Algar, Baeckens, Buchkowski, Fabre, Frank, Geneva, Reynolds, Stroud, Velasco, Kolbe, Mahler, and Herrel
Abstract

Extreme climate events such as droughts, cold snaps, and hurricanes can be powerful agents of natural selection, producing acute selective pressures very different from the everyday pressures acting on organisms. However, it remains unknown whether these infrequent but severe disruptions are quickly erased by quotidian selective forces, or whether they have the potential to durably shape biodiversity patterns across regions and clades. Here, we show that hurricanes have enduring evolutionary impacts on the morphology of anoles, a diverse Neotropical lizard clade. We first demonstrate a transgenerational effect of extreme selection on toepad area for two populations struck by hurricanes in 2017. Given this short-term effect of hurricanes, we then asked whether populations and species that more frequently experienced hurricanes have larger toepads. Using 70 y of historical hurricane data, we demonstrate that, indeed, toepad area positively correlates with hurricane activity for both 12 island populations of Anolis sagreiand 188 Anolis species throughout the Neotropics. Extreme climate events are intensifying due to climate change and may represent overlooked drivers of biogeographic and large-scale biodiversity patterns.

 

Are Anoles with Re-grown Tails Easier to Catch?

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On April 29, 2020

In All Posts

In reporting a case of tail bifurcation in a Bahamian brown anole (A. sagrei) from south Eluethera, Sebastian Hoefer and Nathan Robinson (The Cape Eleuthera Island School), write in Herpetology Notes proposing so!

“Another interesting observation was that this individual was particularly easy to capture and did not attempt to escape. The lack of avoidance could be explained by the anole being stunned due to stress at the time of capture. Alternatively, it could be that multiple tails infer higher energetic costs than a single tail. In turn, this could negatively affect the individual’s activity patterns or ability to avoid predators.”

 

 

Hoefer, S. and Robinson, N.J., 2020. Tail bifurcation in a Brown Anole, Anolis sagrei (Duméril & Bibron, 1837). Herpetology Notes, 13, pp.333-335.

Dominance and Anoles: It’s Risky at the Top, But Worth It

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On April 27, 2020

In All Posts

Two anoles duking it out. Photo from sciencesource.com

Give the elaborate and charistmatic behaviours of our favourite lizards — anoles — many researchers have attempted to piece apart the intricacies of anole social dynamics. In a recent study in Zoology, Glenn Borgmans (University of Antwerp) tests whether dominant adult male American green anoles (A. carolinensis) – dominant in relation to other males – are actually at an advantage, for example by establishing priority access to food or other resources, or if risks associated with being the big boss in town outweigh any perceived benefits, like an increased likelihood of injury due to aggressive male-male interactions. You can read all about it here!

 

Abstract
Male Anolis carolinensis lizards will fight and form social dominance hierarchies when placed in habitats with limited resources. Dominance may procure benefits such as priority access to food, shelter or partners, but may also come with costs, such as a higher risk of injuries due to aggressive interaction, a higher risk of predation or a higher energetic cost, all of which may lead to an increase in stress. While most research looks at dominance by using dyadic interactions, in our study we investigated the effect of dominance in a multiple male group of A. carolinensis lizards. Our results showed that dominant males in a multiple male group had priority access to prey and potential sexual partners but may run a higher risk of predation. We could not confirm that dominant males in a multiple male group had a higher risk of injuries from aggressive interactions or a higher energetic cost by being dominant. Overall our results seem to indicate that dominant male A. carolinensis lizards in a multiple male group obtain clear benefits and that they outweigh the disadvantages.

Dominant lizards ate more food items (left; A) and hid less (right; B) than more submissive individuals.

Borgmans, G., Van den Panhuyzen, S. and Van Damme, R., 2020. The (dis) advantages of dominance in a multiple male group of Anolis carolinensis lizards. Zoology, 139, p.125747.

Salmonella in Japan’s Green Anoles

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On April 25, 2020

In All Posts, Introduced Anoles, New Research

When I hear or read Salmonella, I think of my mom explaining to my 7-year-old self why I shouldn’t eat raw chicken (to be clear, I never expressed interest in doing this, but lesson learned nonetheless). According to the U.S. Centers for Disease Control and Prevention, most instances of Salmonella bacteria making people sick do in fact result from transmission by food. But Salmonella infection can come from other sources, including direct contact with living animals, particularly reptiles (including birds which, in case you haven’t heard, are reptiles). So I was only a little surprised when I came across a recent paper in the Journal of Veterinary Medical Science, based in Japan, documenting the prevalence of Salmonella in the green anole, Anolis carolinensis, on Okinawa Island, Japan.

Of the 706 green anoles from Okinawa Island whose intestinal contents were analyzed for Salmonella presence between 2009 and 2014, only 2.1% tested positive. That number is low compared with published results for green anole populations in Florida (7.5%), Chichi Island in Japan (34.2% – this study was highlighted here on Anole Annals when it came out in 2013), and Guam (76.2%). I’m struck by how much these percentages vary. Green anoles have been in Florida for millions of years, whereas populations in the other locations have only been established for tens of years. The authors hypothesize that infection rate in recently introduced populations should correlate with how long the population has been established. Testing this hypothesis will require data from more populations.  It also appears that we know little about whether anoles are affected by carrying Salmonella, although a quick search did reveal this study involving the brown anole, Anolis sagrei.

All told, we have a lot to learn about anoles and Salmonella. In the meantime, please protect yourself from Salmonella infection by following basic food safety precautions: refrigerate foods adequately, wash fruits and vegetables and cook meat and eggs thoroughly, and clean potentially contaminated cookware and utensils with soap and water. Most importantly, WASH YOUR HANDS, although I assume that like me, you are already doing this approximately a hundred times per day (for those of you reading this in the future, I’m not a weirdo. We’re in the middle of a pandemic).

For those who may be interested, green anoles became established in and around Japan several decades ago and are considered an ecologically disruptive pest. If you want to read more, here are links to some old Anole Annals posts on various topics related to the region’s green anoles: trapping efforts, population age structure, range expansion. Enjoy!

Does Breeding Season Variation Affect Evolution of a Sexual Signaling Trait in a Tropical Lizard Clade?

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On April 22, 2020

In New Lit Abstracts

New literature alert!

In Ecology and Evolution
Gray, Barley, Hillis, Pavón‐Vázquez, Poe, White
Abstract

Sexually selected traits can be expected to increase in importance when the period of sexual behavior is constrained, such as in seasonally restricted breeders. Anolis lizard male dewlaps are classic examples of multifaceted signaling traits, with demonstrated intraspecific reproductive function reflected in courtship behavior. Fitch and Hillis found a correlation between dewlap size and seasonality in mainland Anolis using traditional statistical methods and suggested that seasonally restricted breeding seasons enhanced the differentiation of this signaling trait. Here, we present two tests of the Fitch–Hillis Hypothesis using new phylogenetic and morphological data sets for 44 species of Mexican Anolis. A significant relationship between dewlap size and seasonality is evident in phylogenetically uncorrected analyses but erodes once phylogeny is accounted for. This loss of strong statistical support for a relationship between a key aspect of dewlap morphology and seasonality also occurs within a species complex (A. sericeus group) that inhabits seasonal and aseasonal environments. Our results fail to support seasonality as a strong driver of evolution of Anolis dewlap size. We discuss the implications of our results and the difficulty of disentangling the strength of single mechanisms on trait evolution when multiple selection pressures are likely at play.

 

Thermal Sensitivity of Lizard Embryos Indicates a Mismatch Between Oxygen Supply and Demand at Near-lethal Temperatures

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On April 17, 2020

In New Lit Abstracts

New literature alert!

In Journal of Experimental Zoology
Hall and Warner
Abstract

Aspects of global change create stressful thermal environments that threaten biodiversity. Oviparous, non‐avian reptiles have received considerable attention because eggs are left to develop under prevailing conditions, leaving developing embryos vulnerable to increases in temperature. Though many studies assess embryo responses to long‐term (i.e., chronic), constant incubation temperatures, few assess responses to acute exposures which are more relevant for many species. We subjected brown anole (Anolis sagrei) eggs to heat shocks, thermal ramps, and extreme diurnal fluctuations to determine the lethal temperature of embryos, measure the thermal sensitivity of embryo heart rate and metabolism, and quantify the effects of sublethal but stressful temperatures on development and hatchling phenotypes and survival. Most embryos died at heat shocks of 45°C or 46°C, which is ~12°C warmer than the highest constant temperatures suitable for successful development. Heart rate and O2 consumption increased with temperature; however, as embryos approached the lethal temperature, heart rate and CO2 production continued rising while O2 consumption plateaued. These data indicate a mismatch between oxygen supply and demand at high temperatures. Exposure to extreme, diurnal fluctuations depressed embryo developmental rates and heart rates, and resulted in hatchlings with smaller body size, reduced growth rates, and lower survival in the laboratory. Thus, even brief exposure to extreme temperatures can have important effects on embryo development, and our study highlights the role of both immediate and cumulative effects of high temperatures on egg survival. Such effects must be considered to predict how populations will respond to global change.

 

Hall, JM, Warner, DA. Thermal sensitivity of lizard embryos indicates a mismatch between oxygen supply and demand at near‐lethal temperatures. J Exp Zool. 2020; 1– 14.

 

Anolis cristatellus Journal Cover!

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On April 15, 2020

In All Posts, New Research

Hot off the press — the latest anole journal cover! In this issue of Nature Ecology & Evolution, Shane Campbell-Staton and I led a team of researchers to explore the effects of urban heat islands on anoles. We found that not only can urban Anolis cristatellus tolerate higher temperatures than their forest counterparts, but also identified genomic regions associated with divergent thermal tolerance. Check out a summary of this work at the urban evolution blog I co-edit, Life in the City: Anoles Adapt to Beat the Urban Heat.

Anole Online Learning Resources

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On April 13, 2020

In All Posts, Education and Anoles

The days of self-isolation and quarantine are dragging on as COVID-19 continues its worldwide rampage. We may all be a little less productive than we had thought we would be as we tend to unruly kids and rogue parents who won’t stay indoors. Here at Anole Annals, we’ve scoured our past posts and brainstormed some of our favorite learn-at-home resources to help keep you entertained at home while learning about your favorite lizards!  Whether you’re a seasoned researcher looking for a break, a teacher in search of remote learning activities, or a parent at home with kids in need of educational activities, we hope you find the following resources useful.

 

HHMI BioInteractive

HHMI produced several fantastic videos and learning modules perfect for learning about anoles, ecology, and evolution in the classroom and at home! Each of the activities also comes with handy educator materials to make sure your newly homeschooled students gets the most out of these resources.

The Origin of Species: Lizards in an Evolutionary Tree — This short video (~17 minutes) covers the concepts of adaptation, islands as natural laboratories, speciation, and convergent evolution. Pair the video with the associated interactive activities and discussion prompts to get the most out of this resource. Start with this one, since all of the other activities produced by HHMI relate back to the concepts covered here.

Lizard Evolution Virtual Lab — This all inclusive four part learning module involves videos and an interactive web application (also available for IOS) to learn about ecomorphs, phylogenies, experimental data, and dewlaps. Students will collect and analyze data as they learn about the scientific process and anole themed concepts. The modules also have embedded mini quizzes to make sure your student is understanding the information, and educator materials to help you guide your students as they learn.

The Lone Anole — This activity is a short conversation starter based on a photo of the Plymouth anole (Anolis lividus) to use with students to discuss ideas of adaptation and natural selection.

One of the sample cards for students to “collect data” from in the HHMI  selection by predation activity.

Look Who’s Coming for Dinner: Selection by Predation — In this interactive activity, students are walked through the scientific process to learn how to develop a hypothesis, collect data, and analyze results with plotting and basic statistics. This activity is based on the study: Rapid temporal reversal in predator-driven natural selection (Losos et al. 2006). Everything you need to complete the virtual experiment is included!

Effects of Predation on the Niche of Lizards — This short activity guides students through interpreting a scientific figure from the study: Predation on a common Anolis lizard: can the food- web effects of a devastating predator be reversed? (Schoener, Spiller, and Losos, 2002).

How Lizards Find Their Way Home — This short video (8 minutes) is based on the research of Manuel Leal. Watch a real scientist design an experiment to answer a question and carry out fieldwork radio tracking lizards! Produced by Day’s Edge Productions.

Lizards in the Cold — This short activity based on the study Winter storms drive rapid phenotypic, regulatory, and genomic shifts in the green anole lizard (Campbell-Staton et al. 2017) teaches students how to interpret a scientific figure and is a good conversation starter for discussing natural selection and climate change.

Lizards in Hurricanes — Another short activity based on a study by Donihue et al. (2018): Hurricane-induced selection on the morphology of an island lizard. Students are asked to review a figure from the paper and discuss how hurricanes and other extreme weather events can lead to morphological change, and how scientists can experimentally investigate these changes.

Reproductive Isolation and Speciation in Lizards — This short animated video (~2 minutes) discusses the process of speciation and the role of the dewlap in reproductive isolation in anoles.

Using DNA to Explore Lizard Phylogeny — In this interactive activity students learn how to build a phylogeny based on common traits and then by using DNA sequences to explore the concept of convergent evolution. As with the other activities, everything you need to do this experiment at home is provided digitally.

Read More

Ever Wonder if Anoles Eat Scorpions?

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On April 7, 2020

In All Posts

They do! Rodríguez-Cabrera and colleagues report in the latest issue of Euscorpius: Occasional Papers in Scorpiology on predation on scorpions in Cuba. In addition to the A. homolechis and A. sagrei shown above (left and right, respectively), A. equestris was also observed eating a scorpion.

Help Needed Identifying an Ecuadorian Anole

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On April 4, 2020

In All Posts, Ask the Experts


Recently, a friend found the anole pictured above in Mompiche, Ecuador. As of now, the identity of this anole remains unknown.

The closest matches I could find were Anolis bombiceps and A. lyra, but there were problems with both of those species. Anolis bombiceps lacks a spot on the dewlap, and is not known to occur as far west as Mompiche. On the other hand, Anolis lyra seemingly has either a red or white dewlap without any blue coloration. This individual seems to match up perfectly with A. lyra in all other regards.

This may simply be an individual displaying unusual dewlap coloration, but I’m interested in hearing your thoughts (Editor’s note: AA‘s comment function is broken, so please use the form below).

Thanks in advance!

EDITOR’S UPDATE: SEVERAL READERS WROTE BELLA TO SAY THAT THIS IS A FEMALE A. LYRA. NOTE THE DIFFERENCE IN COLOR OF THE DEWLAP IN BELLA’S PHOTOS AND THE ONES IN A PREVIOUS POST ON ANOLE DEWLAP SEXUAL DICHROMATISM.

 

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