Panamanian city frogs more attractive


This February 2018 video from the USA says about itself:

The Túngara Frog‘s “Taste For the Beautiful”

Department of Integrative Biology faculty member Michael J. Ryan discusses animal sexual selection and evolution in his new book “A Taste for the Beautiful”. Ryan is the Clark Hubbs Regents Professor in Zoology at The University of Texas at Austin and a Senior Research Associate at the Smithsonian Tropical Research Institute in Panama. He is a leading researcher in the fields of sexual selection, mate choice, and animal communication.

From the University of Texas at Austin in the USA:

Females prefer city frogs’ tunes

December 10, 2018

Urban sophistication has real sex appeal — at least if you’re a Central American amphibian. Male frogs in cities are more attractive to females than their forest-frog counterparts, according to a new study published in Nature Ecology and Evolution.

Frogs in urban areas have more conspicuous and complex vocal calls, in part because they have fewer predators than those in natural habitats, say scientists from Vrije Universiteit (VU) in the Netherlands, The University of Texas at Austin, Purdue University and the Smithsonian Tropical Research Institute in Panama.

University of Texas at Austin professor of integrative biology Mike Ryan joined team leader Wouter Halfwerk and colleagues to investigate how city life has altered the signaling behavior of male túngara frogs. The trappings of cities often interfere with animal communication, as noise and light pollution affect the visual and auditory signals animals use to attract mates. Halfwerk previously has published work showing how urbanization affects birdsong in Europe.

The research team recorded the characteristic ‘chuck’ calls made by the one-inch frogs living in forests near the Panama Canal and in nearby human-disturbed areas, including small towns and cities. They found that the urban males would call more often and with greater call complexity, meaning they made more of the ‘chuck’ sounds that females prefer, compared to the frogs in the forest. The authors played back both calls to female frogs in a lab, and they discovered that three-quarters of the females were more attracted to the complex urban calls, compared to the simpler forest calls.

“In the forest, these more attractive calls have a higher cost,” Ryan explained. “The sound can attract frog-eating bats and bloodsucking midges.”

Evolution may select for the trait that allows the frogs to make more complex vocal calls in cities and towns, where the eavesdropping predators are scarcer there than in the forest. To help test this idea, the researchers examined what would happen when they moved urban frogs into forest habitats and forest frogs into urban habitats. It turned out that the urban frogs were able to actively reduce the complexity of their calls in the new environment, but forest frogs couldn’t make the switch to making their calls more complex to attract females.

Ryan, his graduate students and colleagues have been studying sexual selection and communication in the túngara frog for decades. His 2018 popular science book A Taste for the Beautiful describes how males of this species and other species have evolved over the years to attract more females.

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Brazilian tree frogs parenting, new study


This June 2015 video says about itself:

7 Tiny Frogs Found on 7 Brazilian Mountains

Researchers in Brazil discovered seven never-before-seen species of Brachycephalus frog on seven different mountains in the Atlantic forest.

From PLOS:

Not too big, not too small: Tree frogs choose pools that are just right

Frogs breeding in pools of water on leaves face trade-off between drying out and repelling predators

December 5, 2018

Frogs that raise their young in tiny pools of water that collect on plant leaves must make a delicate trade-off between the risk of drying out and the risk of being eaten, according to a study publishing December 5 in the open-access journal PLOS ONE by Mirco Solé from the Universidade Estadual de Santa Cruz in Bahia, Brazil and colleagues.

The temporary pools of water trapped by the leaf rosette of some plants in the Bromeliaceae family are used by a variety of creatures as a source of prey, water and shelter — one example is the Broad-snout casque-headed Tree Frog (Aparasphenodon arapapa) which uses the water ‘tanks’ of bromeliad plants as a place to mate and rear its tadpoles. To understand how the frogs choose the right spot, the researchers measured the characteristics, including size, water level, and leaf debris, of the central tanks of 239 bromeliads in Reserve Boa União in Bahia, Brazil.

They compared bromeliads that were occupied by a tree frog with those that were empty and found that male frogs generally prefer bromeliads with larger tanks, a higher volume of water, and less leaf litter — qualities which make the tanks less likely to dry up and easier to access. However, the very largest and fullest bromeliad tanks were frog-less, suggesting that a trade-off exists when choosing the best place to breed. Males have a specially shaped bony head that they use to form a tight seal with the opening of the bromeliad tank, which is thought to protect them from predators. Forming a tight seal may be tricky in very large bromeliads, making them a poor choice as a shelter.

The authors conclude that the trade-offs animals face when selecting a site to breed should be taken into consideration in conservation strategies.

Solé adds: “Aparasphenodon arapapa, a tropical frog from the Brazilian Atlantic Forest places its eggs into bromeliads, but instead of simply choosing the largest bromeliad tank with the most water, complex trade-offs between selection pressures and balancing water requirements are involved in the bromeliad choice.”

New giant salamander species discovery in Florida, USA


This 2016 video from Spartanburg Science Center in the USA is called One of our sirens eating an earthworm.

From National Geographic in the USA:

New species of giant salamander discovered in Florida

Scientists have discovered a two-foot-long salamander species in Florida and Alabama that has the spots of a leopard and the body of an eel.

By Jason Bittel

December 5, 2018

There have been whispers for decades that a creature with the spots of a leopard and the body of an eel lurked in the swamps of Florida and Alabama. Rumor had it the animal was as long as a man’s arm, with glistening gray skin, and frills on either side of its face.

But unlike Bigfoot and the Loch Ness Monster, this animal is real. And today scientists have given it a name: the reticulated siren.

“It was basically this mythical beast,” says David Steen, a wildlife ecologist at the Georgia Sea Turtle Center and co-author of a paper officially describing the new species published December 5 in the journal PLOS ONE. Informally, people have called it the leopard eel, though it is clearly not an eel (and zero parts big cat).

Sirens are among the world’s largest salamanders—and this species, also known as scientifically as Siren reticulata, grows up to two feet in length. Like other members of the Sirenidae family, these creatures are completely aquatic, Steen says.

Unlike most salamanders, sirens have lost their hindlimbs through millions of years of evolution. They wear their gills on the outside, which absorb oxygen from water in the murky ecosystems they inhabit. Sirens also lack eyelids and sport tiny, horny beaks instead of teeth.

The new species is one of the largest creatures to be described in the United States in over 100 years. And it could have gone longer. Steen says it took about five years of searching ponds and waterways in the Florida panhandle before they could come up with enough specimens to describe the species.

Giant prehistoric amphibians, video


This PBS video from the USA says about itself:

When Giant Amphibians Reigned

9 October 2018

Temnospondyls were a huge group of amphibians that existed for 210 million years. And calling them ‘diverse’ would be putting it mildly. Yet in the end, two major threats would push them to extinction: the always-changing climate and the amniote egg.