Trans-marine Dispersal Inferred from the Saltwater Tolerance of Lizards from Taiwan

Table 2 from Hsu et al. showing the survival rates of lizard eggs exposed to saltwater

New literature alert!

Trans-marine dispersal inferred from the saltwater tolerance of lizards from Taiwan

In PLOS ONE
Hsu, Lin, Liao, Hsu, and Huang

Abstract

Dehydration and hypersalinity challenge non-marine organisms crossing the ocean. The rate of water loss and saltwater tolerance thus determine the ability to disperse over sea and further influence species distribution. Surprisingly, this association between physiology and ecology is rarely investigated in terrestrial vertebrates. Here we conducted immersion experiments to individuals and eggs of six lizard species differently distributed across Taiwan and the adjacent islands to understand if the physiological responses reflect the geographical distribution. We found that Plestiodon elegans had the highest rate of water loss and the lowest saltwater tolerance, whereas Eutropis longicaudata and Emultifasciata showed the lowest rate of water loss and the highest saltwater tolerance. Diploderma swinhonisHemidactylus frenatus, and Anolis sagrei had medium measurements. For the eggs, only the rigid-shelled eggs of Hfrenatus were incubated successfully after treatments. While, the parchment-shelled eggs of Elongicaudata and Dswinhonis lost or gained water dramatically in the immersions without any successful incubation. Combined with the historical geology of the islands and the origin areas of each species, the inferences of the results largely explain the current distribution of these lizards across Taiwan and the adjacent islands, pioneerly showing the association between physiological capability and species distribution.

Read the full paper here!

#DidYouAnole – Anolis cuvieri


Photo by Jorge Velez-Juarbe, iNaturalist

Happy Anole Day!

Here’s another crown-giant anole, Anolis cuvieri, the Puerto Rican Giant anole.


Photo

The Puerto Rican Giant anole is, as the name suggests, native to Puerto Rico. These anoles typically have an SVL of 132 mm, and both sexes have large tail crests. While these bright green anoles can turn darken and turn brown, this species also has a rare brown morph! Juvenile cuvieri are grey-brown with striping and shift to their signature green when they mature.


Photo by Graham Reynolds

They eat insects, mainly beetles, moths and butterflies, and also occasionally fruit, snails, birds and of course, other anoles.


Photo by sas103, iNaturalist

Puerto Rican Giant anoles prefer rainforest and can be found where there are lots of large trees together.

Green Anole and Giant Day Gecko Locked in a Duel

It’s invasive eat native time again here in Florida, where this poor but brave male green anole somehow found himself in a battle with a giant invasive gecko, Phelsuma grandis. Check out the video on ladywildbones’ Instagram page.

Phelsuma grandis is native to Madagascar, but has been introduced to South Florida as well, where several breeding populations exist in the Florida Keys.

Phelsuma grandis found in the Florida Keys | Image Credit: Delton Howard/iNaturalist

They eat insects, fruit, nectar, and any animal that will fit into their jaws, including anoles! Like anoles, Phelsuma are aggressive, territorial, and fast-growing. They are the ultimate Florida invader, though rivaled in success by the green iguana.

Juvenile Giant Day Gecko caught in the Florida Keys | Image Credit: Delton Howard/iNaturalist

We can probably expect to see more Day Gecko/Anole confrontations as the geckos increase their population.

Tail Autotomy Is Associated with Boldness in Male but Not Female Water Anoles

Photo by Lindsey Swierk

Although most people use “personality” to describe human characteristics, animals also exhibit personality traits, which behavioral ecologists categorize as aggressiveness, exploration, activity, sociability, and boldness. Each personality trait is linked to inherent trade-offs that could affect one’s overall fitness, and may differ between the sexes due to different life history strategies. Boldness is a personality trait that includes behaviors such as risk-taking, response to predators, and resistance to being handled. It is assumed that bolder individuals are more likely to “take chances” and forage under predation risk compared to less bold individuals, whereas less bold individuals may spend more time scanning for predators and less time foraging.

Austin Carriere (The University of Oklahoma), Dr. Lindsey Swierk (Binghamton University – SUNY), Dr. Bree Putman (California State University San Bernardino) and I investigated the sex differences in the trade-offs between boldness and predator avoidance in water anoles (Anolis aquaticus), using the voluntary shedding of the tail (tail autotomy) as a proxy for predation risk. This project involved a two-year mark-recapture study, morphological data collection, and behavioral trials. We conducted and recorded boldness trials in the field for all captured adult anoles, and we analyzed the video footage in the lab. We quantified boldness as the latency for a lizard’s head to emerge from a refuge into a novel environment.

Fig 1. Adjusted survival curves showing how tail break (yes or no) affected time to head estimated from the Cox proportional hazard model in a) female and b) male water anoles. Survival rate is the proportion of individuals still in the refuge.

We found that there were sex-differences in the costs of boldness, as tail autotomy was positively associated with boldness in males but not in females. Tail autotomy has been shown to have serious fitness consequences in lizards; therefore males likely suffer a higher cost of boldness. We also found that males tended to be more likely to show evidence of tail autotomy. Our results could be due to the fact that lizards exhibit a polygynous mating system, wherein males defend territories to acquire mates, and so males may exhibit bolder behavior to increase their reproductive success. However, the trade-off of boldness in males is the higher probability of tail autotomy, probably due to increased exposure to predators or more involvement in aggressive encounters with conspecifics. Our study contributes to the understanding of sex differences in behavior within an ecological context.

Source: Talavera, J.B., Carriere, A., Swierk, L., Putman B.J. Tail autotomy is associated with boldness in male but not female water anoles.  Behav Ecol Sociobiol 75, 44 (2021). https://doi.org/10.1007/s00265-021-02982-w

#DidYouAnole – Anolis equestris

Photo by Karl Guyton II

Hi!

Welcome back. I lost a family member and took a break, but I’m back now and thank you for coming back.

I picked the Cuban Knight Anole for today because there’s just so much anole to love.

Anolis equestris are crown-giant anoles and the largest known species of anole with an SVL of 10-20 cm in males and 9-17 cm in females. Their tails can be about twice their body length. They are territorial and will gape and display at perceived threats, while raising its body.

Cuban Knight anoles are native to Cuba, but have since been introduced to places like Turks and Caicos, Florida, Hawaii and the Canary Islands.


Photo by Ultra Violet

These large anoles eat pretty much whatever they want to, including the usual anole fare like insects, nectar, other smaller lizards, and fruit and plant matter. They are actually able to pass on viable seeds! Cuban Knights have also been seen eating other animals that are smaller than themselves, like birds, scorpions, and frogs.


Photo by Paul Richards

Both males and females have dewlaps, which for this species have no pattern and are pale pink. There are 11 subspecies of the Cuban Knight anole, including A. equestris poitor, also called the Blue Beauty for its blue colouring that becomes more prominent and overt in its dark phase. These are only found in Cayo Santa María, an island off Cuba’s north central coast.


Photo by Jesús Reina Carvajal

Thanks for reading!

Here’s a video of a female digging a possible nesting site for your time.

Taiwan Tries a New Tack to Get Rid of Invasive Festive Anoles

From the pages of the Taiwan News. We’ve had posts on the invasion of festive anoles into Taiwan previously.

Facing invasive lizard dilemma, Taiwan tries a different tack

Brown anole has caused eco-havoc in Taiwan, but a research team in Chiayi may have the answer 

A brown anole displaying. (Wikipedia, Creative Commons photo)

A brown anole displaying. (Wikipedia, Creative Commons photo)

The brown anole (Anolis sagrei), an invasive lizard species native to Cuba and the Bahamas, has been causing damage to Taiwan’s ecosystems for years, but solutions to controlling its spread have been elusive.

Now a university research team in Chiayi County is trying a different approach — working with plant nurseries in parts of the county to get rid of anole eggs from plant soil — that appears to be promising. Chiayi County was the entry point for the non-native species and has been at the epicenter of its proliferation for nearly two decades.

During that time, the county government has tried to grapple with the problem because of the serious threat posed by the lizard to Chiayi’s biodiversity, said Chen Hsun-wen (陳宣汶), an assistant professor in National Chiayi University’s Biological Resources Department. From 2009 to 2017, local authorities focused their eradication campaign on offering financial incentives to the public for getting rid of the lizards, a system that spurred increased interest in catching brown anoles and controlling their population.

Eventually, however, the county discovered that the more than NT$10 million (US$356,951) in cash rewards handed out through the incentive program did not translate into control of the brown anole population, according to Chen. It may even have been counterproductive, he said, because it caused problems in compiling accurate statistics and resulted in inefficiencies in getting rid of the lizards.

Reptile reputation

That led the Forestry Bureau’s Chiayi Forest District Office to consider a new approach — outsourcing a brown anole prevention and control project to a research team in Chen’s department in 2018. The team adopted a strategy of containing the reptiles instead of slaughtering them and put in place measures to confine them to areas where they already existed to keep them from spreading.

The team’s primary target has been plant nurseries, a common sight in Chiayi, after it found that brown anoles were most likely to spread to different areas through the movement of seedlings and saplings shipped by those nurseries, said Hsu Wei-chieh (徐偉傑), an assistant research fellow in the department.

According to Hsu, the lizards usually lay their eggs in the soil of nursery plants and hide in the branches and leaves of saplings, and the containment plan is aimed at getting nurseries to check for the lizards or their eggs when a batch of seedlings or saplings are shipped out.

Floridians

To assist the nurseries in the effort, the team has dispatched workers to monitor the nurseries and help them check for lizards or their eggs and get rid of them before products are shipped, Chen said.
Because of the difficulty in spotting the lizards or their eggs, the team also sets traps at the nurseries to catch the reptiles.

Chen said gauging the population of the brown anoles is not easy, but it appears that the team’s efforts are having some impact, as the population of lizards in Shuishang Township in Chiayi County, while still high, appears to be growing at a much slower rate than previously. Shuishang Township has several nurseries where many varieties of tree saplings imported from the U.S. grow, and it is where the lizard species was first found in Taiwan.

A genetic analysis found that Taiwan’s brown anoles came from Florida, Chen said, and he believes they came through imports of plants and plant products from Florida that had the eggs of brown anoles in their soil.

The team is now hoping that through their focus on controlling the brown anole population at their source, the species can be contained and be stopped from damaging Taiwan’s ecosystems.

How Well Can Anoles Perceive the Patterns on Anole Dewlaps?

From the pages of Chipojo Lab:

“Manuel recently published a paper in the Journal of Herpetology with Leo Fleishman and Maya Prebish, examining visual acuity and perception of Anolis dewlap patterns. Yesterday, a news feature came out about the article in El Nuevo Día, sharing the findings en español. Keep scrolling below for an English translation!”

Read the entire, extremely interesting post here!

Brown Anole Stands Up to A Dog: the Video

A while back, Nancy Greig, Director of the Cockrell Butterfly Center at the Houston Museum of Natural Science, reported on an interaction with Freddie, her 27-pound dog, and a brown anole. Well, Freddie’s been at it again!

Here’s what Nancy has to say:

That dog-Anolis sagrei interaction I sent a photo of several months ago was not a one-off. Yesterday Freddie encountered another good-sized male that again would not back down. He could have run away, but seemed to think he was much bigger that he was.

I also “tested” him by touching his tail. He opened his mouth and extended his dewlap (I did this more than once), but did not try to run away. He could easily have run to hide, but like the first one, was extremely feisty (or had a death wish). I’m not sure if he eventually got away, but he certainly had many opportunities that he did not take.

I think it’s just the big male anoles that are so tough/stupid. The smaller ones run away.

 

#DidYouAnole – Anolis lucius


Photo by djhiker, iNaturalist

Congratulations on the 46th President to all the Americans! Its only day 2 so he still’s brand new, but that doesn’t mean the work is done!

Speaking of work, I’ve been thinking about this anole (previously seen here) since Anolis bartschi.

Anolis lucius, or the Slender Cliff anole, is another endemic Cuban anole. It can be found close to urban areas and in similar karstic habitats to the Western Cliff anole. They also can be found inside caves where they also lay their eggs, sticking them to the walls (Hardy, 1957). They have a cyclical reproductive cycle, mating and laying their eggs in the wet season, after egg production occurs in the dry season.


Photo by Alex Alfil, iNaturalist

Slender Cliff anoles have a really pretty design with almost circular striping at the top of their heads and striping down their sides. They have a translucent lower eyelid, the purpose of which is unknown. Possibly to help filter out light when they initially emerge from the caves? Is anyone studying these anoles right now? Can you email me? For science??


Photo by Shea Lambert

In the meantime, here’s a paper about winter aggregation. Socially distant huddles! Cute!

Thermal Ecology and Activity Pattern of the Lizard Anolis onca (Squamata: Polychrotidae) in Araya Peninsula, Venezuela

Adult male Anolis onca from Isla de Margarita basking, by Gabriel N. Ugueto

We all know that anoles have subdigital lamellae; however, there is one species in which these lamellae are lacking: Anolis onca, which is known for being a sand-dwelling anole. In 2011, Dr. Jennifer Velásquez and colleagues published a paper in SABER, in which they studied the differences in thermal ecology and the activity pattern of male and female Anolis onca in Araya Peninsula, Venezuela, during the dry and wet season in a dry forest (10 m a.s.l). This study was conducted from September 2004 to April 2005, during which time 56 individuals were captured (15 females and 41 males). Dr. Velásquez and colleagues measured body temperature (Tb), substrate temperature (Ts) on the capture site, and air temperature (Ta).

Dr. Velásquez and colleagues found that in males and females, the Tb was higher during the dry season compared to the wet season: 33.6 ºC (30.0 – 37.2; n = 23) and 33.6 ºC (30.0 – 35.5; n = 7) for males and females, respectively, during the rainy season, and 34.4 ºC (33.0 – 35.8; n = 18) and 34.3 ºC (34.0 – 35.7; n = 8) during the dry season. Mean Ta and Ts were also higher during the dry season compared to the rainy season; during the dry season, Ta was 37.4 ± 0.69 ºC (n = 30) and Ts was 38.4 ± 0.69 ºC (n = 30), while during the rainy season, Ta was 33.9 ± 0.82 ºC (n = 26) and Ts was 34.9 ± 1.58 ºC (n = 26). In addition, Dr. Velásquez and colleagues found that A. onca changes its timing of activity depending on the season. During the rainy season, A. onca is more active from 9:00 am to 10:00 am, and during the dry season from 12:00 am to 1:00 pm; during both seasons, there is low activity from 3:00 pm to 5:00 pm.

The authors argued that there is a relationship between Tb, Ta and Ts during the rainy and the dry season, in which the thermophysiology of A. onca is influenced by the climate variability of the microhabitat it occupies, suggesting that this species is a thermoconformer. In conclusion, the body temperature of this species varies during the day and across seasons, and it also varies as air and substrate temperature vary.

Abstract:

Aspects of the thermal ecology and activity pattern of the lizard, Anolis onca, during the dry and rainy season, and both periods in a belt of xerophytic forest located in the Araya Peninsula, Sucre state, Venezuela. The mean body temperature of A. onca was 33.9 ± 1.50 ºC in both periods to A. onca, while it reached 34.4 ± 0.75 ºC during the drought period and 33.6 ± 1.87 °C during the rainy period. In both climate periods, we found positive and significant correlations between body temperature with air and substrate temperature. The results suggest that thermoregulation is done passively, influenced by microhabitat temperature (air and substrate). There was a unimodal daily activity pattern during both periods. The thermal niche breadth was greater in males, while niche overlap between sexes was higher during the rainy period.

Read the full paper here!

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