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Traffic noise stresses out frogs, but some have adapted

Frogs from pounds near highways show a dampened stress response and altered immune profile when experimentally exposed to noise compared…

Frogs from pounds near highways show a dampened stress response and altered immune profile when experimentally exposed to noise compared to frogs from quiet ponds. This suggests that frogs from noisy ponds have adapted to reduce the negative effects of traffic noise. Credit: Tracy Langkilde, Penn State

Frogs from noisy pounds near highways have altered stress and immune profiles compared to frogs from more quiet pounds-changes that reduce the negative effects of traffic noise on the amphibians. Ifølge en ny undersøgelse, når frogs from quiet ponds are experimentally exposed to traffic noise, the noise is stressful and impairs the production of antimicrobial peptides-an important defense mechanism against pathogens. Dog, frogs taken from ponds near highways show a dampened stress response and altered immune profile, both of which reduce the costs of traffic noise. The study appears online November 21

, 2018, in the Royal Society Journal Proceedings B .

“In the United States, traffic noise can be heard almost everywhere,” said Jennifer Tennessen, first author of the paper who was a graduate student at Penn State at the time of the research and is currently a research associate at Western Washington University. “Noise can have a number of negative consequences on wildlife, for example, by interfering with communication and reducing the ability to find food. Frogs are particularly vulnerable to noise because they depend on sound to find mates and reproduce. Wood frogs travel to ponds in the jump to mate and lay their eggs, but many of these ponds are located near noisy roads. We wanted to know if traffic noise has negative physiological effects on wood frogs and if so, whether they can adapt. “

The researchers collected Eggs from ponds located less than 300 feet from interstates and major highways and from ponds in more isolated settings, up to 3 miles from major roads. De eieren werden verhoogd door metamorfose in de lab, en de resulterende frogs werden blootgesteld aan of verkeersstoringen of omgevingsgeluiden die vergelijkbaar waren met die bij de stille ponden gedurende 8 dagen, over de lengte van de tijd die zij zouden uitgeven op broedvijvers.

De onderzoekers vonden dat frogs uit de stille ponden hadden verhoogde levels van de stresshormooncorticosteron na blootstelling aan verkeerslawaai voor 8 dagen, wat aangeeft dat de noise is stressvol. Noise exposure also affected immune function in frogs from quiet sites, increasing counts of a type of white blood cell called monocytes-an indication of an immune response to noise and impairing the production of important compounds on the skin called antimicrobial peptides.

“In frogs from quiet ponds, exposure to traffic noise impaired the ability to produce antimicrobial peptides in the brevinin and temporin families,” said Louise Rollins-Smith, professor of pathology, microbiology, and immunology at the Vanderbilt University School of Medicine and an author of the paper. “Antimicrobial peptides are components of the immune defense system that provide important protection against pathogens like bacteria and fungi. Brevinin-family peptides specifically inhibit the fungal pathogen that causes the infectious disease chytridiomycosis, or chytrid, which is responsible for widespread mortality of amphibians around the world. “

Wood frogs rely on sound to find mates and reproduces, but many breeding ponds are located near noisy roads. A new study reveals that traffic noise is stressful to frogs and impairs the production of antimicrobial peptides – an important defense mechanism against pathogens like the chytrid fungus. Credit: Lindsey Swierk

“Long term elevation of stress hormones can lead to negative immune consequences,” said Tracy Langkilde, professor and head of biology at Penn State and senior author of the paper. “Så vi kunne forvente å se undertrykkelse af stresspåvirkningen efter langvarig stress eksponering for å redusere immunforsvaret, som for eksempel den ændrede produktion af hudpeptider, som vi dokumenterede her.” I frogs from noisy ponds, we see just that. “[19659005] Frogs from noisy ponds did not have elevated levels of corticosterone after exposure to traffic noise for 8 days, suggesting that frogs from ponds in high-noise areas have a suppressed stress response.

“We are not sure if the frogs from Noisy sites have a suppressed stress response to noise specifically or if they have a suppressed stress response overall, “said Langkilde. “Both offer the benefit of avoiding stress-related costs of noise, but having a dampened stress response in general could have other negative effects, for example not being able to properly mount a behavioral response to predators.”

Unlike frogs from quiet ponds, which had increased monocyte counts when exposed to traffic noise, frogs from noisy ponds had actually increased monocyte counts when exposed to the ambient noise heard at quiet ponds. De forskere mener at dette barns immunforsvar kan ske i ukendte situationer, og støtter ideen om at frogs fra støyende steder har tilpasset seg for å unngå de fysiologiske kostnader for støy.

“I fremtiden håber vi at fastlægge mekanismen for hvordan frogs are adapting to noise, “said Tennessen. “De veje nær de pond vi studerede var bygget mellem 1940’erne og 1960’erne, så disse ændringer kunne have forekommet inden for 15 til 35 frog generationer. Folk pleier at tænke på tilpasning og evolution over store tidsplaner, men her vi ser at dyr kan reagere relativt snel tot nieuwe threats, hoewel de gevolgen van die reactie nog steeds onduidelijk zijn. “

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More information:
Frogs adapt to physiologically costly anthropogenic noise, Proceedings of the Royal Society B rspb.royalsocietypublishing.or … .1098 / rspb.2018.2194

Journal reference:
Proceedings of the Royal Society B

Provided By:
Pennsylvania State University

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