Science Current Events | Science News | Brightsurf.com
 

Lizard moms may prepare their babies for a stressful world

April 20, 2012
Stressed out lizard moms tend to give their developing embryos short shrift, but the hardship may ultimately be a good thing for the babies once they're born, according to a study published in the journal Physiological and Biochemical Zoology.

Stress changes the way animals allocate energy. During predator attacks or food shortages, hormones are released that help the body to access stored energy. But for pregnant females there's a potential trade-off. Stress hormones could rob precious energy from developing embryos, leading to offspring that aren't as healthy.

A research team led by Erik Wapstra of the University of Tasmania, Australia, tested the effects of stress on southern grass skinks, which, unlike many lizards, give birth to live young rather than laying eggs.

In the lab, the researchers recreated the physiology of a stressful situation by artificially raising levels of the stress hormone corticosterone in pregnant skinks. Other skinks had their food intake limited, recreating the stress of a food shortage. The team then measured the health of the stressed mothers and their eventual offspring, and compared their state to mothers and offspring that weren't under stress.

The study found that stressed moms gave birth to smaller offspring that grew more slowly than those born to low-stress mothers. Stressed mothers themselves were found to be in better physical shape after giving birth than non-stressed mothers. That's a signal that when stressors are present, mothers tend to allocate energy to self-preservation first.

Despite seemingly getting the short end of the stick, the news wasn't all bad for offspring of stressed mothers. "We found that small offspring had larger fat reserves relative to body size-, which may enhance offspring survival in a stressful post-natal environment," the researchers write. Previous studies have also shown that smaller juvenile lizards often do better when predator density is high or when food availability is low.

It appears that a mother's stress-induced selfishness may actually help to pre-adapt her babies for a stressful world.

###

Keisuke Itonaga, Susan M. Jones, and Erik Wapstra, "Do Gravid Females Become Selfish? Female Allocation of Energy during Gestation." Physiological and Biochemical Zoology 85:3 (May/June 2012).

Physiological and Biochemical Zoology primarily publishes original research papers in animal physiology and biochemistry with a specific emphasis on studies that address the ecological and/or evolutionary aspects of physiological and biochemical mechanisms. Studies at all levels of biological organization from the molecular to the whole organism are welcome, and work that integrates levels of organization to address important questions in behavioral, ecological, evolutionary or comparative physiology is particularly encouraged.

University of Chicago Press Journals


Related Physiological Biochemical Zoology Current Events and Physiological Biochemical Zoology News Articles


Summertime cholesterol consumption key for wintertime survival for Siberian hamsters
Increasingly, scientific findings indicate that an organism's diet affects more than just general health and body condition.

Energy requirements make Antarctic fur seal pups vulnerable to climate change
A new study suggests that climate change could pose a risk for Antarctic fur seals in their first few months of life.

Here's venom in your eye: Spitting cobras hit their mark
Spitting cobras have an exceptional ability to spray venom into eyes of potential attackers. A new study published in Physiological and Biochemical Zoology reveals how these snakes maximize their chances of hitting the target.

Study shows hibernating bears conserve more muscle strength than humans on bed rest do
A fascinating new study from the May/June 2007 issue of Physiological and Biochemical Zoology quantifiably measures the loss of strength and endurance in black bears during long periods of hibernation.
More Physiological Biochemical Zoology Current Events and Physiological Biochemical Zoology News Articles

© 2015 BrightSurf.com