Tuesday, April 11, 2017

Crack pots, insanity, and some really sick human beings

Snakes provide a variety of ecosystem services, not the least of which is rodent control. This is a free service provide by nature. However, like much of what is free, Republicans insist on privatizing it so somebody can make a profit.

Arizona HB2022 failed on a tie vote yesterday (April 10, 2017). The bill, if passed, would have allowed citizens to shoot "snake shot" within city limits in the State of Arizona. The Arizona Daily Star today (April 11) attributes the failure of the bill to a letter from Mike Cardwell an employee of the San Bernadino County Sherrif's office (California) and a herpetologist. Kudo's to Mike for sending the letter. The Cardwell letter included the following "The bottom line when it comes to destroying small animals like rattlesnakes is that that gun fire presents a much greater danger to by-standers than the snake itself."

Where is the Hantavirus when you need?  Oh, the snakes are controlling the rodents that carry it! The New Mexico Department of Health announced April 7th that a 54-year-old man from San Juan County has died of Hantavirus Pulmonary Syndrome (HPS). This is the second case of HPS confirmed in New Mexico this year. Snakes control rodents that carry this virus and reduce the probability that it will be transmitted to humans.

Just so you understand where this kind of proposed legislation comes from - here is the argument for the law, made by Chris Eger, at Guns.com. The comments that accompany this post are eye-opening.

A House measure advancing through committee would allow the use of specialty ammo inside Arizona cities for snakes and rats but is drawing fire from animal rights groups.
The bill, proposed earlier this month in the state House, has been winding its way through hearings and has gotten an initial nod from lawmakers, though its sponsor cautions it is not an animal regulation proposal.
“It’s a firearms bill,” said Rep. Jay Lawrence, R-Scottsdale. “It’s not a bill that deals with harming snakes or rats or any other vermin, it merely is a firearms bill.”
Lawrence’s measure, HB 2022, would amend state law to allow the use of rat or snake shot to control pests. The cartridges, instead of using a solid bullet, utilize a plastic cap or shell that holds a quantity of small diameter shot. The bill’s language only allows for .22 caliber shot rounds with pellets 1.3mm or less in diameter.
Currently, only the use of blanks is allowed within city limits to control pests.
Not all are impressed by the bill, especially reptile advocates who point out there are at least four species of endangered snakes at large in Arizona.
Russ Johnson of the Phoenix Herpetological Society told local media the proposal is fraught with pitfalls.
“Do we really want people shooting guns in the city limits next to houses?” said Johnson. “You’re talking about shooting rats. So you’re shooting on your rooftop, so you got bird shot spraying everywhere. OK, if you’re shooting a snake, you’re pointing down. You’re gonna get a ricochet even though it’s pellet.”
HB 2022 has passed both the JPS and Rules committees.
Filed Under: Ammunition, Politics & 2nd Amendment


Monday, April 10, 2017

Logging & Leatherbacks


Leatherback turtle hatchlings. Photo Credit: Juan Patiño
 Debris from logging in tropical forests is threatening the survival of hatchling leatherback turtles and the success of mothers at one of the world's most important nesting sites in Colombia.

New research by the University of Exeter and the Doñana Biological Station in Seville, Spain, has found that debris on beaches caused by logging activity is impacting both young turtles and their mothers during the key periods of their life cycles.

Leatherbacks are at particular risk of being caught up in fishing nets and longlines as bycatch, because they are migratory, travelling long distances worldwide.

Many breeding sites are already under pressure from tourism.

But now, research published in the journal Marine Ecology Progress Series has revealed that the logging is an additional, previously underestimated threat.

To nest and breed successfully, females must be able to cross the sandy beaches to dig their nest to successfully incubate their eggs.

In turn, hatchlings must be able to cross the sand unaccompanied to reach the water.

Researchers found that the beach debris hindered this movement.The team monitored 216 turtles, comparing their activity in areas with high amounts of debris to low amounts, in a globally significant nesting site in Colombia.
 
They also manipulated the amount of debris to see how it changed behavior.

They found that females which nested in areas with higher amounts of debris were spent more time building their nest and tended to do so closer to the shoreline.

This meant they were more vulnerable to flooding, which puts their eggs at risk.

Some females were even wounded in the process.

The debris also meant it took longer for hatchlings to reach the sea, increasing their chance of being eaten by predators and meaning they had to expend more energy, making them more vulnerable.

Professor Brendan Godley, director of the Centre for Ecology and Conservation at the University of Exeter's Penryn Campus in Cornwall, is a co-author on the research.

He said: "Leatherback turtles are already under immense pressure, from fisheries bycatch and are also one of the species prone to ingesting marine plastic litter.

"Our research clearly indicates that logging presents another threat.

"It is now paramount that beach clean-up operations are built into logging activities to prevent further damage to this species."

Dr Adolfo Marco Llorente, of the Doñana Biological Station, said: "Although logging debris does not affect rates of nesting, it has a significant impact on where and how nests are built, which negatively affects both mothers and hatchlings.

"This is on a scale that could lead over time to reduction of the overall population.

"Simple measures could make a real difference, such as repositioning organic waste areas, or salvaging the wood debris as an energy source.

"It's also essential that logging practices that reduce the impact on the marine environment are implemented."



 Patino-Martinez J, Godley BJ,  Quiñones L,  Marco A. 2017.  Impact of tropical forest logging on the reproductive success of leatherback turtles. Marine Ecology Progress Series, 569: 205 DOI: 10.3354/meps12064

Friday, April 7, 2017

Lowland amphibians are at higher risk from future climate warming.


A new study of Peruvian frogs living at a wide variety of elevations -- from the Amazon floodplain to high Andes peaks -- lends support to the idea that lowland amphibians are at higher risk from future climate warming.

That's because the lowland creatures already live near the maximum temperatures they can tolerate, while high-elevation amphibians might be more buffered from increased temperatures, according to a study by University of Michigan ecologist Rudolf von May and his colleagues published online April 6 in the journal Ecology and Evolution.

Previous studies have suggested that lowland reptiles and amphibians are especially vulnerable to climate warming. But in most cases, those conclusions were based on computer modeling work that incorporated a limited amount of field data.

"Understanding how species respond to climatic variation is critical for conserving species in future climatic conditions. Yet for most groups of organisms distributed in tropical areas, data about species' critical thermal limits are limited," said von May, a postdoctoral researcher in the U-M Department of Ecology and Evolutionary Biology.

"I think the contribution of our study is that it focuses on a group of closely related frog species distributed along a single montane gradient and that it includes empirical data on species' tolerance to heat and cold, as well as air temperatures measured along the same gradient."

In the process of conducting the study, which involved more than two years of fieldwork, von May and his colleagues identified three previously unknown frog species. Those newly discovered species will be described separately in a series of journal articles.

The elevational-gradient study focused on the thermal ecology and evolution of 22 species of land-breeding frogs, which are also known as terrestrial-breeding frogs, in southern Peru's Manu National Park and surrounding areas. Sampled elevations ranged from the Amazon River floodplain, at 820 feet above sea level, to 12,000-foot Andes Mountains peaks.

The region in and around Manu National Park is known for long-held records of biodiversity including more than 1,000 species of birds -- about 10 percent of the world's bird species -- and more than 1,200 species of butterflies. In addition, the park contains an estimated 2.2 percent of the world's amphibians and 1.5 percent of its reptiles.

While most frogs lay eggs in water, terrestrial-breeding frogs use a specialized reproductive mode called direct development: A clutch of embryos hatch directly into froglets; there are no free-living tadpoles. Terrestrial-breeding frogs form a diverse group that can exploit a wide variety of habitats, as long as those locations contain sufficient moisture.

In the study, the researchers looked at how closely related frog species differ in their elevational distribution and their tolerance to heat and cold in a region of the tropical Andes where temperature increase is predicted to be detrimental for most species.

"These measurements were taken in order to determine whether tropical frogs could take the heat -- or cold -- predicted for tropical regions as a result of climate change," von May said.

The researchers found that the frogs' tolerance to heat varied from 77 degrees Fahrenheit to 95 degrees and that, as expected, highland species tolerated much lower temperatures than lowland species.

Frogs living in high-elevation grasslands tolerated near-freezing temperatures, which they experience during the dry season, as well as moderately high temperatures, which they may experience during sunny days.

When considering the temperature of the microhabitats in which the frogs live, the results suggest tropical lowland species live close to their thermal limit. Amphibians living at high elevation might be more buffered from future temperature increases because the highest temperatures they can tolerate are farther away from the maximum temperatures that they regularly experience in the wild.

Von May is the first author of the Ecology and Evolution paper, "Divergence of thermal physiological traits in terrestrial breeding frogs along a tropical elevational gradient."

Citation
Rudolf von May, Alessandro Catenazzi, Ammon Corl, Roy Santa-Cruz, Ana Carolina Carnaval, Craig Moritz. Divergence of thermal physiological traits in terrestrial breeding frogs along a tropical elevational gradient. Ecology and Evolution, 2017; DOI: 10.1002/ece3.2929



Wednesday, March 15, 2017

Cobras - Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting

Bryan Frye and a cobra.
A University of Queensland-led international study has revealed how one of the world's most feared types of snakes -- cobras -- developed their potent venom.

Associate Professor Bryan Fry of UQ's School of Biological Sciences said cobras were killers in Africa and Asia, and caused crippling social and economic burdens through the number of survivors who needed amputations due to the snake's flesh-eating venom.

"While we knew the results of their venom, how the cobra's unique defensive venom evolved remained a mystery until now," he said.

"Our study discovered the evolutionary factors shaping not only cobra venom, but also the ornate markings on their hoods, and the extremely bright warning colourings present in some species."

The research team studied 29 cobra species and related snakes, finding that the flesh-destroying venom first evolved alongside the broad hoods that make cobras so distinctive.

Dr Fry said further increases in the potency of the toxins subsequently occurred parallel to their warning strategies such as hood markings, body banding, red colouring and spitting.

"Their spectacular hoods and eye-catching patterns evolved to warn off potential predators because unlike other snakes, which use their venom purely for predation, cobras also use it in defence," he said.

"For the longest time it was thought that only spitting cobras had these defensive toxins in high amounts in their venoms, however we've shown that they are widespread in cobras.

"These results show the fundamental importance of studying basic evolution and how it relates to human health."

Dr Fry said the next step in the team's research was to conduct broad antivenom testing.

"Globally, snakebite is the most neglected of all tropical diseases and antivenom manufacturers are leaving the market in favour of products that are cheaper to produce and have a bigger market," he said.

"Antivenom is expensive to make, has a short shelf life and a small market located in developing countries.

"Therefore, we need to do further research to see how well those remaining antivenoms neutralise not only the toxins that kill a person, but also those that would cause a severe injury."

He said there may also be a benefit to this research in cancer treatment.

"Any kind of compound that selectively kills cells could be a good thing," Dr Fry said.

"These chemicals may lead to new cancer treatments if we can find ones that are more potent to cancer cells than normal healthy cells.

"Cobras are a rich resource of novel compounds in this way so there may ultimately be a silver lining to this very dark cloud."


Citation

Panagides N, Jackson TN, Ikonomopoulo MP. Arbuckle K, Pretzler R, Yang DC, Ali SA, Koludarov I, Dobson J, Sanker B, Asselin A, Santana RC, Hendrikx I, van der Ploeg H. Tai-A-Pin J, van den Bergh R. Kerkkamp HM, Vonk FJ, Naude A, Strydom MA, Jacobsz L, Dunstan N. Jaeger M, Hodgson WC, Miles J, Fry BG. 2017 How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting. Toxins  9, 103.

Monday, March 13, 2017

Hypsiboas punctatus, the first fluorescent frog

Before and after. The polka-dot tree frog in natural light
 (top) and under UV (bottom.)Photo credit: Julian Faivovich
 & Carlos Taboada 
The first fluorescent frogs have been discovered in South America. The green fluorescence is due to a compound found in the lymph and skin glands of the polka-dot treefrog (Hypsiboas punctatus). At twilight, the phenomenon enhances the frogs’ brightness and may help them communicate with each other.

Fluorescence has previously been reported in fish, scorpions and birds, but never amongst the 7000 plus species of amphibians. The blue–green glow of the polka-dot tree frog was observed when they were under UV light and is linked to a new fluorescent compound, not previously known in nature. The compound absorbs light in the violet–ultraviolet region and emits blue–green light. Time-of-flight mass spectrometry showed that the main fluorescent compound was the molecule Hyloin-L1. NMR revealed an N-methyl-dihydroisoquinolinone core.

‘It is basically a benzamide with a methoxy group added on, which makes the absorption band fall on the edge of the visible spectrum,’ notes Andrew Beeby at Durham University, UK, who was not involved in the study. He adds that this ‘DayGlow frog’ adds to our growing awareness of bioluminescence. The isoquinolinone structure has never before been described in any animals, only in plants. The chromophore seems to be the cyclic benzamide.

‘This is very different from fluorophores found in other vertebrates, which are usually proteins or polyenic chains,’ says author Maria Gabriela Lagorio, a photochemist at the University of Buenos Aires, Argentina. ‘The chromophore itself is well known, but the class of the secondary compound is completely new,’ adds co-author Norberto Peporine Lopes, a natural product chemist at the University of São Paulo in Brazil.

Hyloin L-1 (H-L1) is the molecule that is principally responsible for the polka-dot tree frogs’ fluorescence, although the other molecules pictured also contribute Biologist Karen Carleton at the University of Maryland notes that like many colourful compounds, ‘it contains lots of carbon–carbon double bonds with lots of π electronics that can easily be excited at visible wavelengths. It is also similar to a compound like 11-cis retinal, which is the chromophore that our eye uses to absorb light.’

The discovery is a bolt out of the blue for most in the field. ‘We were not expecting this bio-fluorescence. It was an incredible surprise,’ says Lopes. He suspects the frog, which has translucent skin, uses the phenomenon to communicate. Lagorio agrees: ‘Amphibian species have photoreceptors in their eyes maximally attuned to blue and green vision, so we expect that these compounds enhance the brightness of these frogs under conditions of twilight.’ The team has now begun examining the polka-dot’s relatives. ‘We expect that this will be a more universal phenomenon with perhaps 100 or 200 species showing this property,’ says Lopes.

‘It would be interesting to investigate if [fluorescence] has a role in species recognition, or whether it facilitates the formation of couples,’ notes Bibiana Rojas, ecologist at the University of Jyväskylä, Finland. ‘Fluorescence would be potentially very useful in a noisy environment and in a habitat with dense foliage, as it would make individuals brighter.’

Citation

Taboada C, Brunetti AE, Pedron FN, Neto FC,  Estrin DA, Bari SE, Chemes LB,  Lopes NP, Lagorio MG, Faivovich J. 2017. Naturally occurring fluorescence in frogs. PNAS 2017 doi:10.1073/pnas.1701053114

Saturday, March 11, 2017

A new homalopsid snake from Myanmar

Gyiophis salweenensis Photo credit. Evan Quah
The 54th species of homalopid snake has been described by Quah et al. (2017). The new species, Gyiophis salweenensis was described from the lowlands of Mawlamyine District in Mon state, southeastern Myanmar. The authors suggest that Gyiophis salweenensis  is presumed to be closely related to G. maculosa Blanford and G. vorisi Murphy based on the similarities in scales and coloration but can be separated from G. maculosa by the shape of its first three dorsal scale rows that are square, ventral scale pattern that lacks a central spot, and a faint stripe on dorsal scale rows 1–4. It can be further distinguished from G. vorisi by its lower number of ventral scales (129 vs. 142–152), lower number of subcaudals (30/29 vs. 41–58), narrow rostral scale, and having more rows of spots on the dorsum (four vs. three). A preliminary molecular analysis using 1050 base pairs of cytochrome b (cytb) recovered G. salweenensis  as the sister species to the Chinese Mud Snake (Myrrophis chinensis). G. maculosa and G. vorisi were unavailable for the analysis. The discovery of G. salweenensis sp. nov. highlights the need for more surveys into the herpetological diversity of eastern Myanmar which remains very much underestimated.

Citation
Quah ES, Grismer LL, L Jr PE, Thura MK, Zin T, Kyaw H, Lwin N, Grismer MS, Murdoch Ml. 2017. A new species of Mud Snake (Serpentes, Homalopsidae, Gyiophis Murphy & Voris, 2014) from Myanmar with a first molecular phylogenetic assessment of the genus. Zootaxa. 4238(4):571-82.

Wednesday, February 22, 2017

Tiny frogs from the Western Ghats

Seven new species discovered from the Western Ghats. A. Radcliffe's Night Frog (Nyctibatrachus radcliffei), B. Athirappilly Night Frog
 (Nyctibatrachus athirappillyensis), C. Kadalar Night Frog (Nyctibatrachus webilla), D. Sabarimala Night Frog (Nyctibatrachus sabarimalai),
 E. Vijayan's Night Frog (Nyctibatrachus pulivijayani), F. Manalar Night Frog (Nyctibatrachus manalari), G. Robin Moore's Night Frog.
[(D-G. Size of the miniature species in comparison to the Indian five-rupee coin (24 mm diameter)]. Photo Credit: SD Biju
Scientists from India have discovered seven new frog species belonging to the genus Nyctibatrachus, commonly known as Night Frogs. This find is a result of five years of extensive explorations in the Western Ghats global biodiversity hotspot in India. Four out of seven of the new species are miniature-sized frogs (12.2-15.4 mm), which can comfortably sit on a coin or a thumbnail. These are among the smallest known frogs in the world.

Unlike other frogs in the genus that are predominantly stream dwelling, the new miniature frogs were found under damp forest leaf litter or marsh vegetation. Scientists were surprised by the relative abundance of these previously unknown species at their collection localities. "In fact, the miniature species are locally abundant and fairly common but they have probably been overlooked because of their extremely small size, secretive habitats and insect-like calls," says Sonali Garg who undertook this study as part of her PhD research at University of Delhi.

In the lab, the newly sampled frogs were confirmed as new species by using an integrated taxonomic approach that included DNA studies, detailed morphological comparisons and bioacoustics. Evidence from these multiple sources confirmed that the diversity of Night frogs is higher than previously known and particularly remarkably for the miniaturized forms. Previously, the Night Frog genus composed of 28 recognized species of which only three were miniature-sized.

Now the total number of known Nyctibatrachus species has increased to 35, of which 20 percent are diminutive in size. This frog genus is endemic to the Western Ghats of India and represents an ancient group of frogs that diversified on the Indian landmass approximately 70-80 million years ago.

The discovery of several new species of ancient origin can provide useful insights into the evolution of endemic frog lineages in the Western Ghats, which is a leading amphibian hotspot. The past decade has witnessed an exponential increase in the number of new amphibian species described from this region. Of the total new species of amphibians (1581) described globally between the years 2006-2015, the highest number were from the Brazilian Atlantic Forest (approximately 182) followed by the Western Ghats-Sri Lanka biodiversity hotspot (approximately 159), with 103 species described alone from the Western Ghats region.

However, the future of many of the new species may be bleak. All the newly described species are currently known only from single localities in the southern Western Ghats, and some lie outside Protected areas. Researchers found the Radcliffe's Night frog and the Kadalar Night Frog inside private or state-owned plantation areas facing threats such as habitat disturbance, modification and fragmentation. The Athirappilly Night Frog was found in close vicinity to the Athirappilly waterfalls and the Sabarimala Night Frog near the Sabarimala pilgrimage centre, both of which are disturbed by anthropogenic activities. "Over 32 percent, that is one-third of the Western Ghats frogs are already threatened with extinction. Out of the seven new species, five are facing considerable anthropogenic threats and require immediate conservation prioritization," says Prof SD Biju, who led the new study and has also formally described over 80 new species of amphibians from India

Citation
Sonali Garg, Robin Suyesh, Sandeep Sukesan, SD Biju. Seven new species of Night Frogs (Anura, Nyctibatrachidae) from the Western Ghats Biodiversity Hotspot of India, with remarkably high diversity of diminutive forms. PeerJ, 2017; 5: e3007 DOI: 10.7717/peerj.3007

Tuesday, February 21, 2017

Phylogenetics of Kingsnakes in the Lampropeltis getula Complex, in Eastern North America

Distribution of kingsnakes in the Lampropeltis getula complex in North America:
 (A) Lampropeltis californiae (banded); (B) Lampropeltis holbrooki;
 (C) Lampropeltis nigra; (D) Lampropeltis getula getula; (E) Lampropeltis getula 
“sticticeps”; (F) Lampropeltis getula floridana; (G–I) Lampropeltis getula 
meansi (patternless, striped, and wide-banded, respectively); (J) Lampropeltis 
splendida; (K) Lampropeltis getula nigrita; (L) Lampropeltis californiae 
(striped). Distributions are modified after Conant and Collins (1998),
 Krysko (2001), Stebbins (2003), Krysko and Judd (2006), and 
Pyron and Burbrink (2009a, 2009b).
Kingsnakes of the Lampropeltis getula complex range throughout much of temperate and subtropical North America; along the Pacific coast from Oregon southward to the Mexican Plateau, and eastward to New Jersey and southward to Florida. Kingsnakes of this species complex are extremely variable in color pattern, and therefore, along with their mostly docile disposition, are easily recognizable and very popular in the pet trade.The distinct morphology and color patterns found in the Lampropeltis getula complex, along with its transcontinental geographic distribution and occasional disjunct populations across the North American
Distribution and locations of samples sequenced for kingsnakes 
of the Lampropeltis getula complex in eastern North America: yellow 
dots = Lampropeltis getula floridana from Florida peninsula; blue dots = 
Lampropeltis getula getula from the Atlantic coast; red dots = Lampropeltis 
getula meansi from the Eastern Apalachicola Lowlands in the Florida 
panhandle; gray dots = morphological intermediates between L. g. floridana
 and L. g. getula; and coral dots = morphological intermediates between 
L. g. getula and L. g. meansi. Green and pink polygons refer to Lampropeltis
 nigra and Lampropeltis holbrooki, respectively, on the western side of the 
Appalachian Mountains. Distributions are modified after Conant and 
Collins (1998), Krysko (2001) using multi-locus phylogeny, 
and Krysko and Judd (2006) using morphology.
landscape make a fascinating subject for phylogeography. In a new paper Krysto et al (2017) expanded the sample from the getula complex and add a nuclear DNA locus to the molecular data set  used previously to hypotheses distinct genetic lineages. They use genetic and ecological methods to test previous hypotheses of distinct evolutionary lineages by examining 66 total snakes for: analyzing phylogeographic structure using 2 mtDNA loci and 1 nuclear locus; estimating divergence dates and historical demography among lineages in a Bayesian coalescent framework, and; applied ecological niche modeling (ENM). The molecular data and ENMs illustrate that three previously recognized subspecies in the eastern United States comprise well-supported monophyletic lineages that diverged during the Pleistocene. The geographic boundaries of these three lineages correspond closely to known biogeographic barriers (Florida peninsula, Appalachian Mountains, and Apalachicola River) previously identified for other plants and animals, indicating shared geographic influences on evolutionary history. Them authors conclude that genetic, ecological, and morphological data support recognition of these 3 lineages as distinct species (Lampropeltis floridana, Lampropeltis getula, and Lampropeltis meansi).

Citation
Krysko KL, Nuñez LP, Newman CE, Bowen BW. Phylogenetics of Kingsnakes, Lampropeltis getula Complex (Serpentes: Colubridae), in Eastern North America. The Journal of heredity. 2017 Jan 24.

Saturday, February 18, 2017

Climatic and geographic predictors of life history variation in Eastern Massasauga, Sistrurus catenatus

A juvenile Eastern Massasauga. Photo credit: Eric Hileman.

A new study is bringing attention to a little known and imperiled rattlesnake that slithers among the wetlands in regions surrounding the Great Lakes.

The Eastern Massasauga rattler was once common in such states as Indiana and Illinois. Until recent years, it could still be found in Chicago's Cook County. But the reptile's range and numbers have been steadily declining. In 2016, the snake was listed as threatened under the U.S. Endangered Species Act.

In the new study, Northern Illinois University biological sciences professor Richard King and his former student Eric Hileman examine the life history of the Eastern Massasauga, revealing important local climate impacts on the snake that should be carefully weighed when developing conservation strategies.

"Our results provide evidence that climatic variation in the Great Lakes region strongly influences body size, individual growth rates and key aspects of reproduction," says Hileman, first author of the study published in PLOS ONE, a journal of the Public Library of Science. Hileman earned his Ph.D. in biological sciences from NIU in December and is now a postdoctoral fellow in biology at Trent University in Ontario, Canada.

Hileman, King and more than 40 co-authors gathered and synthesized more than a century of data on the snakes from study sites across the range of the Eastern Massasauga. Most of the data was culled from studies conducted from the mid-1990s forward at sites in Illinois, Indiana, Wisconsin, Michigan, Iowa, Ohio, Pennsylvania and New York, as well as Ontario, Canada.

The scientists found strong evidence for geographic variation in six of nine life-history variables. Among the findings:

The average body size of the snake and the size of its offspring increased with increasing mean annual precipitation, possibly because wetter climates yield greater prey abundance.

Litter sizes decreased with increasing mean temperature, and increased by one offspring for each 1.89-degree increase in latitude, even when maternal size was held constant.

"It's been rare to look within a species and show that these patterns exist," King says. "The study results demonstrate that a one-size-fits all conservation strategy is not appropriate. Rather, assessments of extinction risk and the design of management strategies need to account for geography."

The Eastern Massasauga snakes are generally found in wet prairies or sedge meadows, where the reptiles employ a sit-and-wait strategy to catch and feed on small mammals. Adult size ranges from about 2 feet to 2 ½ feet in length. While venomous, the snakes are not particularly aggressive or dangerous to work with.

"You're not likely to encounter them unless you're looking for them," King says. "It's easy to walk right by one. They're very cryptically colored to look like dead leaves and cattails, so they blend in exceedingly well."

The reptiles suffered habitat loss from extensive drainage of land for agriculture and development. As recently as the 1970s, some states had bounties on the snake.

With concerns over whether they would persist in the wild, the remaining snakes in Chicago's Cook County were taken into a captive breeding program in 2010, King says.

"In Illinois, they've nearly blinked out entirely," he adds. "We're probably down to one location in the southern part of the state that has a stable population. They seem to have stronger holds in Michigan and southern Ontario."

The study authors believe findings will aid Eastern Massasauga recovery efforts.

"The life-history parameter estimates will be essential for improving models related to extinction risk and climate change," Hileman says. "The results from these predictive models can subsequently be used to develop site-specific management strategies."


Citation

Eric T. Hileman, Richard B. King, John M. Adamski, Thomas G. Anton, Robyn L. Bailey, Sarah J. Baker, Nickolas D. Bieser, Thomas A. Bell, Kristin M. Bissell, Danielle R. Bradke, Henry Campa, Gary S. Casper, Karen Cedar, Matthew D. Cross, Brett A. DeGregorio, Michael J. Dreslik, Lisa J. Faust, Daniel S. Harvey, Robert W. Hay, Benjamin C. Jellen, Brent D. Johnson, Glenn Johnson, Brooke D. Kiel, Bruce A. Kingsbury, Matthew J. Kowalski, Yu Man Lee, Andrew M. Lentini, John C. Marshall, David Mauger, Jennifer A. Moore, Rori A. Paloski, Christopher A. Phillips, Paul D. Pratt, Thomas Preney, Kent A. Prior, Andrew Promaine, Michael Redmer, Howard K. Reinert, Jeremy D. Rouse, Kevin T. Shoemaker, Scott Sutton, Terry J. VanDeWalle, Patrick J. Weatherhead, Doug Wynn, Anne Yagi. Climatic and geographic predictors of life history variation in Eastern Massasauga (Sistrurus catenatus): A range-wide synthesis. PLOS ONE, 2017; 12 (2): e0172011 DOI: 10.1371/journal.pone.0172011

Sunday, February 12, 2017

Gliding lizards use the position of the sun to enhance social display

Sulawesi Lined Gliding Lizard (Draco spilonotus
showing the sun on the dewlap
Photo A. S. Kono/Wikamedia
In a recent paper, Klomp et al. describe how a gliding lizard in the genus Draco orient their body to the sun so that the light emphasizes their display. The following is the abstract from the paper.

Effective communication requires animal signals to be readily detected by receivers in the environments in which they are typically given. Certain light conditions enhance the visibility of colour signals and these conditions can vary depending on the orientation of the sun and the position of the signaller. We tested whether Draco sumatranus gliding lizards modified their position relative to the sun to enhance the conspicuousness of their throat-fan (dewlap) during social display to conspecifics. The dewlap was translucent, and we found that lizards were significantly more likely to orient themselves perpendicular to the sun when displaying. This increases the dewlap's radiance, and likely, its conspicuousness, by increasing the amount of light transmitted through the ornament. This is a rare example of a behavioural adaptation for enhancing the visibility of an ornament to distant receivers.

Citation
Klomp DA, Stuart-Fox D, Das I, Ord TJ. 2017. Gliding lizards use the position of the sun to enhance social display. Biology Letters. 2017 Feb 1;13(2):20160979.