Given the chance, parasites evolve to cause less harm

How do you make a parasite less harmful? It might be as simple as forcing them to stick around.

Amanda Gibson from Indiana University performed experimental evolution with the nematode worm Caenorhabditis elegans and a parasitic bacteria (Serratia marcescens), comparing different scenarios for how the parasite was passed on. Under most circumstances, parasites continued to cause their hosts harm throughout the 20-generation experiment. Only when each strain of parasite was allowed to infect the same host strain, generation after generation, did the parasite evolve to become less harmful.

Continue reading

Light Pollution Puts Marsupials Out of Sync

Wallabies living near humans breed later in the season, potentially missing valuable resources that could mean the difference between life and death for their growing offspring.

New research published last month in Proceedings B that found that light pollution in Australia is putting the tammar wallaby (Macropus eugenii) out of sync with the seasons. Robert and colleagues from La Trobe University in Melbourne studied wallaby breeding near urban areas and in natural bush, and found that human light pollution prevents the marsupials from responding to light cues that normally signal the start of the breeding season. Wallabies living near humans had lower levels of melatonin, a hormone linked to the sleep-wake cycle, and gave birth on average 27 days later than wallabies in wild conditions. The authors say that this may lead to a mismatch between the birth of young wallabies and food availability.

Continue reading

Elephant seals are more social than we thought…

For male elephant seals, the fight to secure a mate can be vicious, even deadly. So they try everything they can to avoid it. This is a pattern biologists see again and again – across the animal kingdom, males have evolved to use signals to assess each other’s prowess and avert costly physical confrontations. In most cases, these signals are honest – they accurately convey an individual’s size, strength or dominance. But new research shows this is not the case for Elephant seals, which have evolved a more sophisticated system.

Continue reading

Is Organic Farming Really Better for the Climate?

Organic food is often sold as being the greener alternative. By not pumping toxic chemicals into the environment, we expect that organic farms should do less harm to our wildlife, health and the climate. But new research suggests that current organic farming practises are actually worse for the environment.
Continue reading

Stink Bugs Provide Sunscreen for their Eggs

One scientist found his laboratory stink bugs were laying different colour eggs on the black and white squares of a crossword printed on the newspaper lining of their cage. This small observation led him to begin a series of experiments that show how female stink bugs are able to selectively provide sun protection for vulnerable eggs.
Continue reading

Shy Hermit Crabs Have More Luck with the Ladies

Nice guys finish last? Not for the hermit crab – shy males produce more sperm and are more successful with the ladies.

While we accept the individual differences in behaviour between humans without question, terming it ‘personality’, the idea personality in animals has been met with great scepticism. However, evidence for consistent behavioural differences between individuals, known as personality or behavioural syndromes, is now widespread, the question remaining is why? What is the benefit of personality? Some scientists suggest that different personalities represent different life strategies relating to risk taking and investing in the future, others suggest that personalities exist because environmental conditions are variable and different strategies fair better under different conditions.
Continue reading

Recoding Genes: How Post-Transcriptional Editing is Giving Squid the Upper Hand

Natural selection is incredibly good at adapting organisms to their environment, even those environments that are harsh and difficult to live in. But the changes currently happening to the World’s climate, hydrology and land-use may be too rapid for natural selection to act, in most cases. For some species, natural selection has provided the tools to adapt more rapidly, through behavioural or physiological changes. A few species have gone further still, evolving the ability to edit their own genes as they are expressed. Recent research shows this ability is used rampantly by certain species of squid, which may explain why they have responded relatively well to human impacts on the environment so far.
Continue reading

Evolving the Modern Dinosaur

There are more than 10,000 species of living, breathing dinosaurs on Earth today. It’s just that we call them birds. And while a chicken might seem like a measly ancestor for the enormous T-rex, modern birds can teach us a lot about dinosaur evolution. A huge genome sequencing project, which recently culminated in the publication of nearly 50 genome sequences and the most accurate tree of bird evolution to date, has further blurred the line between bird and dinosaur. Spurring a plethora of studies into the origins of our modern feathered, singing friends, the December 2014 edition of Science taught us that the transition from dinosaurs to birds was gradual and began long before the Dinosaurs were gone. It taught us that it involved multiple independent origins of bird song, a characteristic that now dominates around 10% of the genome. And it taught us that the evolution of flight was facilitated by new genes and new gene regulation, but also by the loss of genes.

Making a Chicken from a T-Rex

Last October, the Therapod Working Group constructed a new phylogeny (family tree) for Dinosaurs, based on morphological characteristics measured in fossil remains of over 150 different species. The new tree revealed fascinating insights into the nature and pace of avian evolution.

Continue reading