All posts by Sofia Prado-Irwin

Evolution 2016: Combat and Display Traits Are Condition Dependent in a Central American Anole

IMG_4616Many exaggerated phenotypic traits, such as the large and colorful dewlaps of male anoles, increase fitness of individuals who possess them. But these traits are often energetically costly. Too high an investment in showy or extreme traits can come at the cost of an individual’s health and performance. Such traits are therefore said to be condition-dependent; that is, individuals will not develop them unless they are already in a healthy condition.

John David Curlis and colleagues explored  several potential condition-dependent traits in two closely related Central American Anolis species, A. limifrons and A. humilis. He quantified a number of sexually and naturally selected traits and tested whether they varied by body condition to see whether any of them were condition dependent, and whether the degree of condition dependence varied between two closely related species. None of the traits he tested were condition dependent in A. limifrons, but two traits – jaw width and dewlap size – were condition dependent in A. humilis. He therefore concluded that the degree of condition dependence of these traits is evolutionarily labile. In addition, A. humilis dewlaps are generally larger than A. limifrons, which suggests that condition dependence may be a more important force affecting traits that are subjected to stronger sexual selection. Taken together, these results suggest that condition-dependence of sexually-selected traits may be playing a role in dewlap diversity (and perhaps other phenotypic traits) throughout Anolis lizards.

Evolution 2016: Evolution of the Thermal Niche in Anolis

IMG_4609Studies of adaptive radiation often focus on two main axes of divergence: the structural niche (e.g., where a species lives) and resource niche (e.g., what a species eats). In his SSE Symposium talk titled “The physiology of adaptive radiation,” Alex Gunderson explained the importance of a third, under-appreciated axis of species diversification: the thermal niche. Gunderson and colleagues tested whether different approaches to estimate the rates of evolution of the thermal niche lead to different conclusions, and whether thermal traits evolve at similar rates to classic ecomorphological traits like body size and limb length.

Scientists generally use three main approaches to quantify the thermal niche and estimate rates of thermal niche evolution: ecological niche modeling (ENM), organismal body temperatures, and physiological data (tolerance/sensitivity to different temperatures). Different studies use different approaches, but few use all three. Each of these metrics addresses a different scale of thermal biology, from broad environmental variables (ENM) to individual organisms (physiology). Gunderson and colleagues therefore predicted that estimated rates of evolution would vary based on the metrics used, and they used data from a number of Anolis species to test this prediction.

Specifically, the authors predicted that: a) ecological niche modeling approaches would estimate greater rates of thermal niche evolution, because environmental factors like temperature and precipitation used in ENM are very broad metrics, and are not necessarily directly correlated with individual thermal niche; b) organismal temperature data would estimate intermediate rates of thermal niche evolution, while it is a measure of individual thermal niche, it is also quite plastic; c) physiological measures would estimate the most conservative/low  rates of evolution, because measures of thermal maxima and minima most accurately reflect the possible tolerance and sensitivity of individuals to thermal environments. They found that physiological data does indeed produce the most conservative estimates of thermal trait evolution, but their predictions about the performance of ENM and body temperature differed. Estimates of thermal niche evolution were highest when using body temperature data, and were intermediate when based on ENM. The fact that body temperature-based estimates of evolution rates were higher than ENM-based estimates suggests that researchers are generally underestimating error in body temperature measurements in the field.

After evaluating the results of these three different approaches in relation to thermal niche evolution, the researchers then compared rates of evolution of thermal traits to those of classical ecomorphological traits. When they used ENM, thermal traits seemed to evolve much more rapidly than morphological traits. In contrast, when they used physiological data, they found the opposite. Clearly, different metrics of climatic niche lead to different conclusions about evolutionary patterns. Gunderson therefore recommends incorporating aspects of multiple ecological and physiological scales when studying divergence of the thermal niche.

Localities for Anolis lemurinus in Costa Rica

Hello AA readers! I’m writing today with a favor to ask. I’m planning to do some research on Anolis lemurinus in Costa Rica this summer, and I’m looking for potential field sites. I’ve been to La Selva Biological Station, which seems to have a healthy population, but if you know of any other localities in Costa Rica where A. lemurinus are abundant, please let me know! I’d greatly appreciate it.

Please contact me at pradoirwin [at] g.harvard.edu

Thanks!

 

Herpetological Field Weekend in Bimini

I recently accompanied postdoc Anthony Geneva on a collecting trip to the small Bahamian island of Bimini for the shortest field excursion I’ve ever been on – four days in total. We were there to collect animals for a breeding colony, and luckily for us, the abundance of anoles on this tiny island is unbelievable. There are four species of Anolis present, each one representing a different ecomorph. Unsurprisingly, the brown anole A. sagrei is by far the most common, but we also saw our fair share of trunk-crown green anoles (A. smaragdinus), trunk anoles (A. distichus), and even a good number of twig anoles (A. angusticeps), which are notoriously hard to spot, so we were pretty excited. The island is also home to healthy populations of curly-tailed lizards (Leiocephalus), whiptails (Ameiva), and several species of gecko, so there was lots to see.

We collected during the day and at night, and were amused by the behavior of some of these lizards. My favorite find was this little guy sleeping under a leafy blanket. He almost fooled us, but that little curl of tail poking out gave him away.

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We were also lucky to witness an adult angusticeps in broad daylight, the first time either of us had ever spotted a twig anole during the daytime. In true twig anole fashion, he kept subtly repositioning himself around the branch to hide, making it rather annoying to photograph him. Nonetheless, it was an exciting find.

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Anolis angusticeps, taken by Anthony Geneva

On the other side of the spectrum was this very bold smaragdinus¸ who jumped from a leaf above and stood right next to me, giving me some solid side-eye before running back up the trunk.

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For a quick four-day trip, we saw a really remarkable diversity of lizards, and we had a great time on Bimini.

 

 

 

Anole Annals Calendars Are Here!

 

anole calendar 1 front

Thanks once again to everyone who participated in our photo contest. We received over 200 photos! The results are in, and the winning photos have been assembled into the Anoles 2016 Calendar! The grand prize winner is the photo above, Anolis bahorucoensis, taken by Carlos De Soto. In second place is the photo below, Anolis cristatellus, taken by JP Zegarra.

cristatellus

You can view the rest of the winning photos in the 2016 calendar here! Congratulations to all the winners!

In addition, because we had so many incredible photos, we have created an extra calendar: Obscure Anoles 2016! This calendar features some of the best photos of less common or rarely seen species and behaviors. We hope you enjoy!

anole calendar 2

Happy holidays, and we wish you all the best in the coming anole-filled year of 2016!

Anole Annals Photo Contest 2015 – Time to Vote!

Thank you to everyone who submitted photos for the AA 2015 contest, we received so many amazing shots! We’ve narrowed it down to the top 40, and now it’s time to vote! Choose your 5 favorites in the poll below.

Reminder: Submit Photos for Anole Photo Contest 2015!

Steven De Decker and Tess Driessens’ winning photo from the 2012 contest.

Thank you to everyone who has sent in photos for our 2016 calendar contest, we’ve received some great submissions! For those who haven’t yet gotten around to it, you’ve still got one week – the deadline is Saturday, November 21. If you have any great anole photos, we would love to have them in the contest! And just to remind you, the first and second place winners will receive a free Anole Annals 2016 calendar, woo! So send in your pics, let’s make the 2016 calendar great!

To remind you, here are the rules: submit your photos (as many as you’d like) as email attachments to anoleannals@gmail.com. To make sure that your submissions arrive, please send an accompanying email without any attachments to confirm that we’ve received them. Photos must be at least 150 dpi and print to a size of 11 x 17 inches. If you are unsure how to resize your images, the simplest thing to do is to submit the raw image files produced by your digital camera (or if you must, a high quality scan of a printed image).  If you elect to alter your own images, don’t forget that it’s always better to resize than to resample. Images with watermarks or other digital alterations that extend beyond color correction, sharpening and other basic editing will not be accepted. We are not going to deal with formal copyright law and ask only your permission to use your image for the calendar and related content on Anole Annals (more specifically, by submitting your photos, you are agreeing to allow us to use them in the calendar). We, in turn, agree that your images will never be used without attribution and that we will not profit financially from their use (nobody is going to make any money from the sale of these calendars because they’ll be available directly from the vendor).

Please provide a short description of the photo that includes: (1) the species name, (2) the location where the photo was taken, and (3) any other relevant information. Twelve winning photos will be selected by readers of Anole Annals from a set of 28 finalists chosen by the editors of Anole Annals.  The grand prize winning and runner-up photos will be chosen by a panel of anole photography experts. Deadline for submission is November 21, 2015.

Good luck, and we look forward to seeing your submissions!

Anole Photo Contest Is Back!

Lucas Bustamante-Enríquez’s Grand Prize-winning photo of A. chrysolepis from the 2013 contest (© Lucas M. Bustamante-Enríquez/TROPICAL HERPING)

We know you’ve all been waiting, so here it is! Anole Annals is pleased to announce the return of the Anole Photo Contest, 2015 edition! We’re closing in on November, which means it’s time to gather the best anole photographs for our 2016 calendar. As with previous contests, the goal is to identify 12 winning photos. The grand prize winner will have his/her photo featured on the front cover of the 2016 Anole Annals calendar, second place winner will have his/her photo featured on the back cover, and they’ll  both win a free calendar! (Check out the 2013 and 2012 winners). We’re a bit late getting things going this year, so get your photos in as soon as you can!

The rules: submit your photos (as many as you’d like) as email attachments to anoleannals@gmail.com. To make sure that your submissions arrive, please send an accompanying email without any attachments to confirm that we’ve received them. Photos must be at least 150 dpi and print to a size of 11 x 17 inches. If you are unsure how to resize your images, the simplest thing to do is to submit the raw image files produced by your digital camera (or if you must, a high quality scan of a printed image).  If you elect to alter your own images, don’t forget that it’s always better to resize than to resample. Images with watermarks or other digital alterations that extend beyond color correction, sharpening and other basic editing will not be accepted. We are not going to deal with formal copyright law and ask only your permission to use your image for the calendar and related content on Anole Annals (more specifically, by submitting your photos, you are agreeing to allow us to use them in the calendar). We, in turn, agree that your images will never be used without attribution and that we will not profit financially from their use (nobody is going to make any money from the sale of these calendars because they’ll be available directly from the vendor).

Please provide a short description of the photo that includes: (1) the species name, (2) the location where the photo was taken, and (3) any other relevant information. Twelve winning photos will be selected by readers of Anole Annals from a set of 28 finalists chosen by the editors of Anole Annals.  The grand prize winning and runner-up photos will be chosen by a panel of anole photography experts. Deadline for submission is November 21, 2015.

Good luck, and we look forward to seeing your submissions!