Fish study links brain size to parental duties


Male stickleback fish that protect their young have bigger brains than counterparts that don’t care for offspring, finds a new University of British Columbia study.

Stickleback fish are well known in the animal kingdom for the fact that the male of the species, rather than the female, cares for offspring. Male sticklebacks typically have bigger brains than females and researchers wanted to find out if the difference in size might relate to their role as caregivers.
In the study, published recently in Ecology and Evolution, researchers compared regular male sticklebacks to male white sticklebacks, which do not tend to their offspring. They found evidence that this change in male behaviour – giving up caring for the young – occurred at the same time the white stickleback evolved a smaller brain.
"This suggests that regular sticklebacks have bigger brains to handle the brain power needed to care for and protect their young," says Kieran Samuk, a PhD student in UBC’s Dept. of Zoology and the study’s lead author. "This is one of the first studies to link parental care with brain size."
The white stickleback is a relatively young species that only diverged from other sticklebacks 10,000 years ago, offering researchers some insight into how quickly brains can evolve.

SOURCE: PHYS.ORG

Fish study links brain size to parental duties

Male stickleback fish that protect their young have bigger brains than counterparts that don’t care for offspring, finds a new University of British Columbia study.

Stickleback fish are well known in the for the fact that the male of the species, rather than the female, cares for offspring. Male typically have bigger brains than females and researchers wanted to find out if the difference in size might relate to their role as caregivers.

In the study, published recently in Ecology and Evolution, researchers compared regular male sticklebacks to male white sticklebacks, which do not tend to their . They found evidence that this change in male behaviour – giving up caring for the young – occurred at the same time the white stickleback evolved a smaller brain.

"This suggests that regular sticklebacks have bigger brains to handle the brain power needed to care for and protect their young," says Kieran Samuk, a PhD student in UBC’s Dept. of Zoology and the study’s lead author. "This is one of the first studies to link parental care with brain size."

The white stickleback is a relatively young species that only diverged from other sticklebacks 10,000 years ago, offering researchers some insight into how quickly brains can evolve.

SOURCE: PHYS.ORG

Fish experience heart failure as water temperature rises


Fish may experience heart failure as ocean temperatures rise due to climate change, according to new research from the University of Auckland.



School of Biological Sciences researchers Anthony Hickey and Fathima Iftikar say the effect of climate change on animals is clear, particularly ectotherms, or cold-bodied animals, such as most fish which rely on their surroundings to maintain optimum body temperature.

"This research shows that the heart acts as a ‘bio-indicator’ of which species may survive rises in ocean temperature but exactly why heart failure occurs we still don’t know,” Dr Hickey says.

The new study, funded through the Marsden Fund and involving Canadian and Australian researchers, found that mitochondria – the power units within heart cells – begin to fail as temperatures rise.

Dr Hickey and Dr Iftikar exposed three species of wrasse from different environments – tropical, temperate and cold – to gradually rising water temperatures. The Australian tropical species Thalassoma lunare (commonly known as moon wrasse) fared worst. These fish inhabit the narrowest thermal range of any species in the study.

"The tropical wrasse could only tolerate a shift of a few degrees before experiencing changes to their mitochondria, and this resulted in a loss of efficiency so that even though the fish could acclimatise to some degree, it came at a cost," Dr Hickey says.

The life-sustaining mitochondria began to fail in all three species before full heart failure occurred, suggesting mitochondrial failure likely accounts for heart failure in heat-stressed animals.

The study suggests that the impact of changes in temperature have an impact on fish mitochondria, limiting the range of environments the fish can occupy. This has important implications if sea temperature rises predicted by climate scientists are accurate, Dr Hickey says.

"Understanding mitochondrial function, or dysfunction, in ectotherms such as fish has important ramifications in terms of climate change and requires more study to investigate the capacity of a wide range of species to survive ocean warming."
Similar responses have been seen in commercially-important crab species, and in heat stressed mammalian mitochondria.
SOURCE: PHYSORG.COM

Fish experience heart failure as water temperature rises

Fish may experience heart failure as ocean temperatures rise due to climate change, according to new research from the University of Auckland.

School of Biological Sciences researchers Anthony Hickey and Fathima Iftikar say the effect of on animals is clear, particularly ectotherms, or cold-bodied animals, such as most which rely on their surroundings to maintain optimum body temperature.

"This research shows that the heart acts as a ‘bio-indicator’ of which species may survive rises in ocean temperature but exactly why occurs we still don’t know,” Dr Hickey says.

The new study, funded through the Marsden Fund and involving Canadian and Australian researchers, found that – the power units within heart cells – begin to fail as temperatures rise.

Dr Hickey and Dr Iftikar exposed three species of wrasse from different environments – tropical, temperate and cold – to gradually rising water temperatures. The Australian tropical species Thalassoma lunare (commonly known as moon wrasse) fared worst. These fish inhabit the narrowest thermal range of any species in the study.

"The tropical wrasse could only tolerate a shift of a few degrees before experiencing changes to their mitochondria, and this resulted in a loss of efficiency so that even though the fish could acclimatise to some degree, it came at a cost," Dr Hickey says.

The life-sustaining mitochondria began to fail in all three species before full heart failure occurred, suggesting mitochondrial failure likely accounts for heart failure in heat-stressed animals.

The study suggests that the impact of changes in temperature have an impact on fish mitochondria, limiting the range of environments the fish can occupy. This has important implications if sea temperature rises predicted by climate scientists are accurate, Dr Hickey says.

"Understanding mitochondrial function, or dysfunction, in ectotherms such as fish has important ramifications in terms of climate change and requires more study to investigate the capacity of a wide range of species to survive ocean warming."

Similar responses have been seen in commercially-important crab species, and in heat stressed mammalian mitochondria.

SOURCE: PHYSORG.COM