SICB 2018: Physiological Traits Predict Behavioral Activity of Female Lizards

One of the most challenging things an organism will do throughout its lifetime is balance its energy budget. Energy is used to grow, develop, reproduce, survive, and how animals allocate that energy will forever be a fascinating question to biologists. If you have more energy, then in theory you should be able to be more active and be a “fitter” individual. For most lizards, excess energy can be represented by fat stores, so if individuals tend to store more energy, then they should be less able to put energy into other reproductive or physiological traits. This was the idea tested by Marzieh Rouzbehani of Trinity University, working in the lab of Michele Johnson.

They studied two anole species: crested and bark anoles (Anolis cristatellus and A. distichus) and found that the two species exhibit different energy-physiology relationships. They found crested anoles with larger eggs had more fat stores, and that crested anoles with larger eggs did not exhibit activity tradeoffs. Bark anoles on the other hand exhibited no relationship between egg mass and fat stores, but found a trend where bark anoles with larger egg masses had lower activity levels. In addition for both species, they found no relationship between hematocrit (the volume percentage of red blood cells in blood) and activity levels, and their work emphasizes the complexity that is species-specific physiological dynamics for female anoles. Different anole species are likely to have different physiological traits influence their behavior and activity in different ways. Fascinating stuff!

SICB 2018: Predicting Climate-Induced Distributional Shifts for Puerto Rican Anoles

Anna Thonis, a Master’s Student in the Lister Lab at Rensselaer Polytechnic Institute, used distributional projection models to predict future ranges of anoles in Puerto Rico. There are ten species of anoles in Puerto Rico, and all of them are predicted to be faced with range shifts in the coming years due to climate change, as Puerto Rico may be faced with both warming and drying out in the future.

Thonis used population occupancy data collected by Lister from 1976-2012 as an input for her models. Using climate models and open source software, Thonis projected anole populations for 2050 and 2070. Based on these models, there will be an average reduction of the most suitable of anole habitats of 29.5% by 2050, and 8 of 10 anole species in Puerto Rico face habitat reduction. In 2070, the models predict and increase in habitat reduction, with a 39.6% reduction in the most suitable habitat and 9 of 10 species of anole facing habitat reduction.

Though these models sound dismal for anoles, Thonis hopes that future work with distributional models can help inform conservation decisions as climate change processes. More detailed models may be able to inform decisions on where protected habitats for anoles should be placed.

SICB 2018: Do back-pattern morphs in female brown anoles differ in morphology, behavior and natural selection?

Sometimes, males and females of the same species differ in traits linked with their ability to survive and reproduce. These differences, called sexual dimorphisms or polymorphisms are quite common in lizards, including anoles! Female brown anoles have a polymorphic back pattern while males are usually of a single pattern. A lot of work has tried to uncover why this back pattern polymorphism exists in nature and what advantages it offers these lizards. Rachana Bhave, a Ph.D. student with Robert Cox at the University of Virginia were interested in determining just how these male and female-like morphs of brown anoles differ in their morphology, behavior, and which traits influence survival.

Using a captive island population in Florida, Bhave et al. captured all of the lizards on the island and measured differences in morphology between the morphs, finding that female-like morphs tend to have higher survival as juveniles but not as adults. These morphs differed in their growth rates but did not experience different selective pressures, indicating perhaps a very complex control regulating the back pattern maintenance in this population. They also found that while female-like morphs tend to display at a higher rate, there weren’t any differences in the morphs probability to attack. They plan to integrate more physiological data such as growth or performance metrics to try and uncover the governing factors responsible for maintaining this back-pattern polymorphism. Awesome stuff to come!

SICB 2018: Environmental Factors Affect Aggression in the Brown Anole

Male-male competition is one of the most widespread phenomena in lizards. Males compete for access to critical food resources, territory space, and female lizards, making a male’s ability to win competitions against other males critical to survive and reproduce. However, how the behavior of a male can vary depending on what social environment he grew up in, the abundance of certain predators or competitors, or the density of other male and female lizards. Therefore, determining what environmental factors influence the behavior of male lizards as they attempt to procure resources necessary to survival and reproduction is a critical question in biology today.

From Virginia Tech, (now a Ph.D. student with Shawn Kuchta at Ohio University) Emily Watts and her collaborators sought to understand what environmental factors influence the behavior of male brown anoles (Anolis sagrei). They used males reared in a common garden from four different populations in the Bahamas to try and determine if genetic or environmental factors influence the aggression differences among males of different populations. Using male-male competition experiments and mirror experiments (where a single male perceives himself as a rival), they tested the hypothesis that males reared in a common garden will not differ in aggressive behavior. They found that aggression varied significantly among populations when using mirror tests, but they found support for their original hypothesis when using male-male competition experiments. This work highlights that aggressive behavior of males is shaped by a multitude of pressures from the environment, to genetics, and ultimately how and where a lizard develops to adulthood. More is to come as they continue to increase the number of their experimental trials with more Anoles!IMG_3929

The Location of the (Neo)Type Specimen of Anolis carolinensis

Bryan Stuart, Curator of Herpetology at the North Carolina Museum of Natural Sciences in Raleigh, recently posted this on Facebook:

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And an important comment on the FB post from Jeff Beane, the department’s collections manager:

“And the neotype of Anolis carolinensis is now NCSM 93545.”

Spiders Eating Anoles and Frogs

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What a horrible way to go! We’ve reported on this before [e.g., 1, 2, 3], but not Folt and Lapinski have published a nice review in Phyllomedusa of wandering and orb weaver spiders eating frogs and lizards in Costa Rica.

The Brown Anole: A Proud Texan

From the pages of the San Angelo Standard Times:

Wild About Texas: Brown anole got to Texas as fast as it could

Living in the day and age where memes on social media are the prevailing means of communication does have a FEW benefits. I can almost always count on having a good laugh daily at something someone has posted.

Just the other day, I saw a meme that stated, “I was not born in Texas, but I got here as fast as I could!” As a naturalist, all I could think about when I saw this posted was one particular species of lizard that has found its way here, and that species is the brown anole.

The brown anole (Anolis sagrei) is one of two species of anoles that currently reside in Texas, but this species is not native to this state. First established near Houston in the 1970’s, this species was known only from areas around Houston, San Antonio and Brownsville as late as the turn of the century.

However, now it can be seen in and among most metro areas within an imaginary triangle that pinnacles in the DFW area, east of I-35 and west of I-45. It has only recently been observed (2016) in the Metroplex, and there have not been enough observations to verify whether there is a breeding population there or not. Even more recently, a smattering of individuals had been reported from a nursery in the city limits of Midland and these observations have been verified.

Originally native to the Bahamas and Cuba, this species has been introduced and is thriving in areas outside of Texas as well. It is arguably the most common lizard observed throughout the southern 2/3 of Florida, and it can also be seen throughout the eastern seaboard of Mexico.

The habitats that this invasive lizard prefers are settings in densely vegetated areas. Although occasional specimens are discovered basking and foraging in short shrubs and trees, the vast majority of sightings are of individuals in terrestrial settings. It is the propensity for living among ornamental plants and shrubs that has enabled this species to thrive in the warmer climates outside of its natural range. Therefore, many Brown Anoles are observed living around landscaped human habitations such as houses and even businesses.

The brown anole is among the most plainly colored and yet most intricately patterned lacertilian species in the United States. Unlike the native green anole (which can vary in coloration from green to tan to brown), this anole is always a shade of brown. The scales on the back are small and granular in appearance and texture, and females are often plainly patterned, adorned only with a light stripe that runs lengthwise down the spine. Males on the other hand are patterned with an intricate array of lightly outlined dark wedges and blotches along the spine.

Both species have varying amounts of dark striping that extends behind the eyes. Males have a brightly colored dewlap that, when extended, is dark red. The limbs are long, and are often colored patterned with dark stripes or bands. The head is not nearly as elongated like the green anole and is not noticeably separated from the body, and the tail, which is colored like the back, is about one-half of the 8-inch total length.

Brown anoles, like other lizard species, are “cold-blooded”, or ectothermic. This means that it does not generate heat from the inside of their body, as mammals and birds do, but rather is dependent on outside sources for heating and cooling. It is active during the early mornings and late afternoons from early April to October, and like many other reptile species it avoids the hottest part of the day by resting in shaded areas. However, the fact that it resides primarily in tropical areas, it is often active throughout the year.

This species of lizard is an opportunistic carnivore, feeding primarily on small insects such as moths, butterflies, crickets, grasshoppers, beetles, and the like.

The brown anole is oviparous, which is a fancy way of saying that it lays eggs. During the breeding season, which typically begins in early spring and extends into late summer, males will attempt to attract females by extending his bright red dewlap (a flap of skin underneath the chin) while bobbing his head up and down in a “push-up” manner.

Following successful copulations, the female will begin to lay clutches of a single egg. By laying an egg about every two weeks, a female can lay as many as 12 eggs in a season. These eggs are laid in areas of high humidity, and typically will hatch in about five weeks. The two-inch long hatchlings are smaller imitations of the female, and are capable of fending for themselves immediately.

This lizard species is a gregarious basker and will often allow people to get rather close as it relies upon its coloration for protection. However, once it feels an intruder has approached too close for comfort, it will quickly dart for cover among the leaf litter.

Michael Price is owner of Wild About Texas, an educational company that specializes in venomous animal safety training, environmental consultations and ecotourism. Contact him at wildabouttexas@gmail.com.

Register Now for the 2018 Anole Symposium

Winning Symposium t-shirt design by Eric-Alain Parker

Winning Symposium t-shirt design by Eric-Alain Parker

Calling all anole aficionados! Spots for the Seventh Anole Symposium on March 17-18, 2018 at the Fairchild Tropical Garden in Miami, Florida are starting to fill up! We have a limited number of spots for attendees and fewer still for presentations. If you have already registered, great! If you haven’t, please do so soon to guarantee your spots. Registering now does not require you to also pay now  – registrants will be contacted in early 2018 to pay the $100 registration fee. Submitting an abstract is not also required at this stage, and can be amended to the registration at a later date.

 

Notes on the Neblina tepui Anole (Anolis neblininus), Discovered in Brazil

Female  Anolis neblininus .

Female Anolis neblininus .

In November 2017, I had the opportunity to join a team of scientists led by herpetologist Miguel T. Rodrigues (University of São Paulo) in an extraordinary expedition to the Serra da Neblina, a very remote tepui (sandstone table-top mountain) on the Brazil-Venezuela border. The expedition involved the Brazilian Army, several Yanomami guides, and a team of BBC journalists. We collected around 2,500 samples of amphibians, reptiles, birds, small mammals, and plants between 80 and 2,995 m of altitude – among them, at least 10 frog and lizard species new to science!

Neblina peak (2,995 m) as seen from our camp at the Bacia do Gelo ("ice bowl", 1,997 m).

Neblina peak (2,995 m), Brazil’s highest mountain, as seen from our camp in the Bacia do Gelo (“ice basin”) at 1,997 m.

As soon as we got to an elevation of around 2,000 m, we started looking for Anolis neblininus, the Neblina anole. This mysterious lizard was described based on six individuals collected on the Venezuelan portion of the mountain in the 80’s by a team of AMNH-Smithsonian scientists. To our surprise, it took us only a few hours to find one, two, several individuals – the first records of A. neblininus in Brazil!

The Neblina anole seems to be locally abundant, with more than 30 individuals found over a week. Because of their slow movements and cryptic coloration, these lizards are really hard to spot during the day. All but two individuals were found at night, sleeping on thin branches and leaves on the edge of forest patches, at a height of 1-4 meters above the ground. Although we set up 100 pitfall traps in the area to sample herps and small mammals, all of the anoles were found through active search.

Neblina anoles really like to sleep on fern leaves - most individuals were found this way.

Neblina anoles really like to sleep on fern leaves – most individuals were found this way.

To learn a bit about how much Neblina anoles move during the day, we experimented with spooling a few individuals. Based on how much thread they left along their way, it seems that A. neblininus does not move much in a day. Individuals go up and down short trees and bushes, but do not seem to walk on exposed ground. However, the spools that we had – leftovers from a study of larger Enyalius lizards – may have been too awkward for such small anoles to carry.

Spooling lizards is an effective way to learn how much they move and what type of substrate they use. Unfortunately the spools that we had were rather big for these anoles.

Spooling lizards is a simple yet effective way to learn how much they move and what type of substrate they use. Unfortunately, the spools that we had were probably too big for these anoles!

Follow the thread to find the lizard!

Follow the thread to find the lizard!

These montane lizards experience remarkably low temperatures. At night, when temperatures were as low as 6oC, the anoles were unresponsive for long periods after captured, apparently because they were too cold. On consecutive mornings, we followed individuals (spotted on the night before) to check at what time they would become active. To our surprise, the anoles started moving at different times in each day, between 6 and 9:30 am, in an apparent association with how cold it was. It is therefore possible that the onset of activity is given mostly by temperature, as opposed to when the sun comes out.

Male Anolis neblininus. Too cold to go anywhere.

Male Anolis neblininus. Too cold to go anywhere.

One interesting feature of A. neblininus is how variable their coloration is. Some individuals have gray bodies, others green or brown; some have yellow heads. They are also capable of changing their colors a bit. The dewlap is well developed in females, with dark spots on an orange or brown background. Male dewlaps are white, bluish, or yellowish. Neblina anoles have a very cool-looking dorsal crest, more developed in males.

Male (left, center) and female dewlaps.

Male (left, center) and female dewlaps.

Our recent studies of mainland anole lizard evolution and biogeography have found that A. neblininus is closely related to species from montane Atlantic Forest, Andes, and Andean foothills. This pattern may result from a history of cool habitats connecting South American mountains in the past, followed by habitat retraction and extinction in intervening areas. Our expedition to the Neblina revealed additional species that seem to be related with taxa from distant mountains. We are now examining their history based on genetic data to help shed light on the history of the mysterious tepui fauna.

When a Meal Can Bite Back

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A Brown Anole (Anolis sagrei) attempts to make a meal of a large centipede.

Anoles eat a wide variety of food items present in their environments, including all sorts of arthropods, and, occasionally, smaller anoles! We might expect that anoles would choose safe, appropriately-sized prey that would reduce chances of injury and guarantee a meal. However, some anoles, including brown anoles (Anolis sagrei), have been seen taking on potential prey that are either quite large (enough that we might foresee trouble actually swallowing the prey item) or poisonous or venomous, such as caterpillars and centipedes.

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Another attempt at subduing the centipede.

Margaret Griffis O’Brien, a contributor to iNaturalist, recently observed just such a showdown on the mean streets of Miami between a brown anole and a centipede nearly its own body size. The anole made repeated attempts to take down the centipede before it was scared away from its potential meal by an intervening automobile. The centipede was injured enough from the battle that it was unable to leave the road and later in the day was found flattened by the continued traffic. The centipede, either an eastern bark centipede or the invasive Rhysida longipes, was a member of the family Scolopendridae, a group of centipedes known to possess powerful and painful (to humans, at least!) venoms.

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The anole’s predation attempt was characterized by a lot of waiting for opportune moments to attack followed by quick strikes at the centipede.

Given that large, venomous centipedes have been documented in the diet of A. sagrei previously, it would be interesting to know if anoles are able to consume centipedes without being envenomated, how susceptible they are to centipede venom, and whether consuming these large, potentially dangerous prey items is advantageous for these lizards.

All photos by Margaret Griffis O’Brien.

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