Many scientists believe that in mammals, there’s a tradeoff between growth and better health. Pugs, for example, are known to live longer than their larger counterpart in the dog world, the Great Dane. But a new study shows that when more energy is allocated to the creation of better cellular materials, longevity is enhanced.

Dr. Chen Hou, an associate professor of biological sciences at Missouri University of Science and Technology, published a paper titled “Energetic cost of biosynthesis is a missing link between growth and longevity in mammals” in the Proceedings of the National Academy of Sciences.

Hou says that his “take-home message” from his research is that if you allocate more energy to making improved cellular materials, you will live longer—a concept that he says engineers may be more familiar with than biologists.

“The existing life history theories suggested a tradeoff between growth and somatic maintenance, meaning more energy spent on growth would result in less for maintaining health,” says Hou. “But this study reveals that the energy cost for biosynthesis is a hidden physiological mechanism underlying the well-established negative correlation between growth and lifespan in mammalian species.”

Hou’s study uses a new research model based on energy conservation to explain the physiological effect of the variation in the energetic cost on the aging process. It also illustrates its role in linking growth and lifespan.

“Previously, the energetic cost of biosynthesis has been thought to be a constant across species and therefore was not considered a contributor to the variation in any life history traits, such as growth and lifespan,” says Hou.

“This study employs a recently proposed model based on energy conservation to explain the physiological effect of the variation in this energetic cost on the aging process and illustrates its role in linking growth and lifespan.”

The study shows that after controlling two energy components—mass-specific metabolic rate and the energetic cost of biosynthesis—there is still a negative correlation between growth constant and lifespan, revealing that the energetic cost of biosynthesis is a link between growth and longevity in mammals.

Hou says that since the energy cost of biosynthesis links growth to aging processes, allocating more energy to growth may enhance somatic maintenance.

He believes the conventional understanding of the tradeoff between growth and maintenance needs to be more carefully analyzed, and that the potential combined effect of metabolic rate and energetic cost of biosynthesis should be considered in similar studies of aging.

While the impact of wildfires on terrestrial life has been well studied, only recently has research started to examine the effects of wildfire ash on aquatic organisms. New research reveals that wildfire ash can have lethal consequences on Australian water ecosystems.

Wildfires are becoming more prevalent due to the warming and drying effects of climate change, with Australia becoming especially vulnerable to dangerous bushfires. “Therefore, many Australian species may be threatened by fires,” says Jenelle McCuaig, a Masters student at the University of Alberta, Canada. “This is putting them at greater risk of endangerment and possible extinction.”

Wildfires release ash into the air, which can enter aquatic environments directly or be washed into bodies of water by rainfall. “Once in the water, ash may leach metals and organic combustion products, where they can affect organisms, acquired by ingestion through intestines or respiration through gills,” says McCuaig. There are also serious consequences for humans, as we rely on healthy freshwater ecosystems for water and food.

McCuaig and her team focused their research on two common Australian crustacean species, a crayfish (Cherax destructor) and a shrimp (Macrobrachium australiense).

To examine the effects of wildfire ash on the crustaceans, each species was exposed to a range of ash concentrations to determine their sensitivity and likelihood of survival. McCuaig then measured their oxygen consumption using a respirometry system and took tissue samples to look at their metabolic activity.

After exposure to just 5g of ash per liter of water, McCuaig found that no shrimps could survive—but it took 8 times as much ash to reach complete crayfish mortality. “The huge difference in sensitivity between the two species was much greater than I expected,” says McCuaig.

This research shows that even between similar species, there can be a big difference in survival response to environmental stressors such as wildfire ash. “Differences in body shape and gill structure, as well as habitat preferences, have allowed them to fulfill different niches,” says McCuaig. “Crayfish demonstrated greater resilience to the ash exposure compared to the shrimp.”

For the surviving crayfish and shrimp, the individuals exposed to the highest concentrations of ash had the highest metabolic rates, suggesting a high level of physiological stress.

“This is particularly concerning during ash exposure, because increased ventilation means that the animals will be taking up more of the ash particles and leached contaminants from the water, further affecting their body systems,” McCuaig notes. “This research will allow us to identify the species that are most threatened by fires and help to inform the development of breeding programs or relocation efforts. When it comes to wildfires, resources are limited, so we must prioritize response actions.”

McCuaig adds that even though many wildfires occur naturally, humans still have a responsibility to protect the living world: “Species conservation begins with wildfire prevention in the first place—it is incredibly important to be educated about, and to implement, fire-safety into our lives to mitigate human-caused wildfires.”

This research is being presented at the Society for Experimental Biology Annual Conference in Prague from 2–5 July 2024.

Under pressure from predatory foxes and cats and competing with feral rabbits, the Greater bilby has lost more than 80% of its habitat. Conservation work led by Professor Carolyn Hogg is designed to help save the bilby from extinction.

A consortium of scientists led by the University of Sydney has for the first time sequenced the entire genome of the Australian bilby. The research is published in the journal Nature Ecology & Evolution.

This first mapping of the bilby’s genetic blueprint, encapsulating biological information on how they grow and evolve, provides an important tool for conservation of the threatened species.

Lesser known than other marsupials, bilbies are often referred to as the Australian Easter bunny and have ongoing cultural significance to Aboriginal Australian communities.

Notable for their large ears and backward facing pouches, bilbies are burrowing nocturnal omnivores. They use their strong forelimbs and long claws to find food and turn over soil and organic matter, making them the ecosystem engineers of Australia’s deserts.

There were once two bilby species, the Lesser bilby, which became extinct in the 1960s, and the Greater bilby that now exists in only 20% of its former habitat range, mostly in the central deserts of Western Australia and the Northern Territory.

Bilby populations went into steep decline after European arrival and the introduction of feral cats and foxes, as well as rabbits competing for food sources. Bilby populations are often managed in the wild by Indigenous rangers, while about 6,000 live in fenced sanctuaries, islands and zoos.

Using DNA from a deceased zoo bilby, a team led by the University of Sydney’s Professor Carolyn Hogg has sequenced the genome of the surviving Greater bilby. The team also created the first genome for the extinct Lesser bilby from the skull of a specimen collected in 1898.

“The Greater bilby reference genome is one of the highest quality marsupial genomes to date, presented as nine pieces, representing each of the bilby chromosomes,” said Professor Hogg from the Australasian Wildlife Genomics Group. “It offers insights into biology, evolution and population management.”

A reference genome is the equivalent of having a puzzle box lid; it’s a way of knowing what all the DNA puzzle pieces mean.

“It helps us understand what gives bilbies their unique sense of smell and how they survive in the desert without drinking water,” Professor Hogg said.

The Greater bilby genome comprises about 38,000 protein coding genes across nine chromosomes with 3.66 billion base pairs. By comparison, the human genome has about 19,900 protein genes across 23 chromosomes with 3.2 billion base pairs.

Importantly, the genome is being used to manage the bilby metapopulation in zoos, fenced sanctuaries and islands.

“By selecting individuals for translocation and release, we maximize their genetic diversity, thus improving the population’s ability to adapt to a changing world.”

The team has also used the genome to develop a more precise scat testing method to complement existing traditional land-use practices by Indigenous rangers.

“We know a lot about bilbies—where they live, what they eat, and how to track them,” said ranger Scott West from the Kiwirrkurra Indigenous Protected Area in Western Australia.

“It’s good to use iPads for mapping, and cameras to monitor them. The DNA work also helps check if bilbies are related, where they are from and how far they traveled. Using old-ways and new-ways together helps us get good information about bilbies and how to look after them. This is what two-way science is.”

“Everything takes four times longer and is four times more difficult when you don’t have a reference genome,” Professor Hogg said. “We have accelerated science to ensure the ongoing survival of bilbies.”

When people think of honey bees, they often think of classic wooden hives, in which beekeepers are having to breed more and more bees just to keep managed populations stable. These man-made boxes, designed to facilitate pollination and honey production in an era before animal welfare was considered, are the hives in which scientists study honey bees.

However, these boxes have little in common with the wild nests that featured in honey bee evolution. Are we are missing something from the evolution of wild bees that might help managed bees today?

Honey bees, originally a tropical insect, colonized cold climates 600,000 years ago by evolving complex behavior patterns for finding and selecting nest cavities in trees.

Swarming honey bees send out scouts to find suitable nests, measure them for fitness against a list of criteria such as height off the ground, volume, entrance size, and entrance location. They communicate this information to the rest of the scouts. Then the scouts engage in a voting system to select the best one and move the entire swarm sometimes over a kilometer, to the new nest.

This tells us that these nests were not that common, even 600,000 years ago. However, the survival advantages warrant investing enormous amounts of energy in finding them.

Disease, predators, parasites and climate change are threatening the future of managed honey bees, pollinators of our food crops. Yet research into these pressures and honey bee behavior rarely takes account of the nest preferences of honey bees shaped by evolution.

For example an international survey of honey bee losses conducted by the Federation of Irish Beekeepers has only three yes/no questions about hives and bee research has no methods or standards on how to evaluate the quality of hives, in contrast to the elaborate measures taken by the bees themselves.

Have we, by putting honey bees into boxes for our own convenience, prevented bees coping with these pressures? Do the bees’ elaborate nest-choosing suggest strategies to help protect them?

One way to answer these questions would be to quantify the physical properties of man made research hives, in relation to the preferences of the honey bees and the context they evolved in. This would mean we could give a hive a scientifically based score relevant to the long term survival of honey bees. It would also form a basis for researching whether human built hives are helping or hindering the honey bees.

My research used the science methods more commonly used for aerodynamics and building simulations (computational fluid dynamics or CFD) and quantified the heat loss differences between hives and the nests honey bees vote for.

Heat retention is important for honey bees as they need to keep the internal temperature of part of their nest above 20°C all year round and part of it close to 34°C for most of the year.

My findings show the tree nests lose substantially less heat than the conventional hives used by researchers. My study also used CFD to visualize the air flows inside both tree and hives, which showed that the internal air circulation within the hive is of substantially different type to that inside the tree nest.

In addition the study has shown that features of man made hives inserted for the beekeeper or researcher’s convenience to easily insert and remove frames actually increase heat losses substantially.

Why has this not been done already?

In the 1930s, all sorts of hive experiments were conducted. By the 1940s, scientists concluded that different hives made little difference to bees. Thus the baseline for research, that hive characteristics could be ignored, was set.

However these experiments did not quantify key physical characteristics (such as heat loss), or determine if the experiments actually changed much physically inside the hive, or measured how man-made hives related to the preferences of honey bees. It was only in the late 1970s that research was carried out into honey bee nest preferences and then later around 2003 into the way honey bees seek out new nest locations and vote for them.

This knowledge about nest preferences and seeking has had little impact on hive based research, probably because the doctrine “hives make no difference” was well established. This means today, as in the 1950s, research does not take into consideration key physical characteristics of the hive nor place them in context with the honey bee preferences that have evolved.

The differences between the hive and the tree nest are so stark, it does call into question whether some research is really about the bees or the bees coping with us.

This article is republished from The Conversation under a Creative Commons license. Read the original article.