Hexbyte Glen Cove Male fairy-wrens show looks can be deceiving thumbnail

Hexbyte Glen Cove Male fairy-wrens show looks can be deceiving

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The researchers found that all male superb fairy-wrens produced and maintained vibrant colours, regardless of their ‘natural quality’. Credit: Alex McQueen

In many animals, female preference for males with the most elaborate appearance is an important factor in the evolution of bright and dramatic colors.

Females are thought to prefer colorful males because only ‘high-quality’ males—those with the most resources, superior foraging skills or social status—can produce and maintain the most vibrant colors.

By choosing these high-quality males, may ensure a good father or good genes for their offspring.

But do high quality males that are preferred by females invest more in their appearance?

A new study by Monash University ornithologists suggests not necessarily.

Led by Ph.D. graduate Dr. Alex McQueen, from the Monash University School of Biological Sciences the study published in Behavioural Ecology examined whether conspicuous colors of superb fairy-wrens signal male quality.

“We examined whether only the best quality males with excellent resources can produce the most vibrant colors and whether only the best quality males can maintain their colors in pristine condition,” said Alex. “We also tested this in an experiment, by administering testosterone to some males which caused them to produce breeding colors in winter.”

“Surprisingly, we found that all male superb fairy-wrens produced and maintained vibrant colors, regardless of their ‘natural quality’. Also the males that had to produce breeding colors in challenging winter conditions displayed vibrant colors that were indistinguishable from other males,” she said.

Every year male superb fairy-wrens change color by molting from a brown non-breeding to an ultraviolet blue and black breeding plumage.

While they are in their breeding plumage, males flaunt their colors to females by performing elaborate sexual displays.

“We predicted that maintaining their colors would be especially important in this species for two reasons: first, males that are preferred by females produce their breeding plumage earlier than all other males, many months before the start of breeding, meaning that those early males display their breeding colors for the longest each year; and second, ultraviolet blue feathers have been shown to readily fade over time in other birds,” said Alex.

The research team measured the colors of the same, wild male fairy-wrens several times a year.

And they recorded how much time males spent preening when they were in their brown non-breeding plumage and colorful breeding plumage.

“We were very surprised to find that male breeding colors do not fade with time,” said Alex.

“Despite keeping their colors in pristine condition, males did not spend more time preening while in breeding plumage,” she said.

The research team found that instead males ‘retouched’ their breeding colors by replacing a few blue feathers at a time throughout the breeding season.

“Our study shows that the vibrant breeding colors of male superb fairy-wrens are unlikely to signal male quality to females,” said Alex.

“We also found that are careful to keep their feather colors in excellent condition for sexual displays.”



Citation:
Male fairy-wrens show looks can be deceiving (2020, December 22)
retrieved 23 December 2020
from https://phys.org/news/2020-12-male-fairy-wrens.html

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Hexbyte Glen Cove Could key gene system discovery be suffocating corals' last gasp? thumbnail

Hexbyte Glen Cove Could key gene system discovery be suffocating corals’ last gasp?

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A unique stress experiment aligned deoxygenation stress to the natural night-day cycle of common reef-building corals from The Great Barrier Reef. Credit: Morgan Bennett-Smith

Oxygen is life, in or out of the water, raising concerns that declining ocean oxygen stores are adding an additional environmental stress to already highly vulnerable coral reef ecosystems. While the twin effects of ocean warming and acidification are well studied, until now there has been limited understanding of how the growing threat of ocean deoxygenation may impact the ability of corals to function and ultimately form reefs.

A unique deoxygenation-reoxygenation stress experiment has given researchers from the University of Technology Sydney (UTS), University of Konstanz and University of Copenhagen insight into how corals manage deoxygenation stress and the key genes that likely drive varied stress susceptibility that commonly results in .

The study, published in Global Change Biology discovered that, like other animals and humans, corals have a similar, sophisticated response to low oxygen levels, or hypoxia. The response is commonly activated during oxygen-deprived exercise and cancer growth in humans

“Ocean deoxygenation is potentially a greater and more immediate threat to coral reef survival than warming and acidification.” lead author and UTS Ph.D. candidate in the Rachel Alderdice said.

“Coral reefs are increasingly being exposed to low oxygen events due to climate change and localised pollution often caused by nutrient run-off.

“The extent to which corals are at risk from future declines in background ocean oxygen levels relies on their hypoxia detection and response systems so to be able to identify this gene response system is significant and exciting,” Ms Alderdice, from the UTS Climate Change Cluster(C3) Future Reefs Research Programme, said.

The unique stress experiment aligned deoxygenation stress to the natural night-day cycle of common reef-building corals from The Great Barrier Reef. Transcriptomic RNA sequencing revealed the key genes expressed that help keystone species such as Acropora tenuis respond to, and tolerate, .

However the research also revealed that not all the coral appeared to be equally sensitive to hypoxia.

“We found those corals that bleached had a delayed, less-effective programming of their hypoxia response gene system compared to the non-bleached coral. The differences in programming abilities for this key gene system may be fundamental to understanding what dictates corals’ capacity to tolerate environmental stress—and ultimately how to more accurately predict the future for ,” University of Konstanz, and senior author, Dr. Christian Voolstra said

The researchers say that the identification of such ‘common switch’ gene repertoires to stress might provide a novel means to identify of interest to guide novel diagnostics for improved reef coral management or as target for selective breeding ‘ restoration’ efforts aimed at increasing coral stress resistance.

Co-author Associate Professor David Suggett, who leads the UTS C3 Future Reefs Research Program said “A fundamental concern we have right now is whether corals and reefs are already feeling the effects of sub-lethal O2 . We have been so preoccupied with unravelling the effects of ocean warming and acidification, we have forgotten deoxygenation, despite its life sustaining role and that is an ocean property we can measure well”.

“This work confirms our recent analysis that continued ocean deoxygenation will play a critical role in shaping the future of our reefs, and yet another reason to urgently tackle ,” he said.



Citation:
Could key gene system discovery be suffocating corals’ last gasp? (2020, November 16)
retrieved 17 November 2020
from https://phys.org/news/2020-11-key-gene-discovery-suffocating-corals.html

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part may be reproduced without the