Older parents may be beneficial to offspring

New research shows how the age of ringworms (Caenorhabditis elegans) affects their offspring. The study showed that older parents had offspring that grew more quickly, had their own offspring at a younger age, and reproduced more often through a normal lifespan.

“Reduced lifespan in the offspring of older parents has been observed in many species, including humans,” said lead researcher Dr. Laura Travers of the University of East Anglia.

“Producing offspring in later life may be harmful to offspring for several reasons. For example, older parents may have lower quality eggs or sperm, or be less well able to take care of their offspring.”  

“On the other hand, in some species it has been shown that older parents can produce more robust offspring because they have more resources to invest and are more experienced in later life which allows them to take better care of their offspring.”

“We wanted to find out more about how parental age influences reproduction and lifespan of offspring. So, we investigated how older parents affect offspring over several generations in roundworms.”

Using the small transparent, soil dwelling worms, the researchers bred several generations. The lifespan and offspring of every second generation was measured. Dr. Travers explained why roundworms were good research subjects.

“They don’t have bones, a heart, or a circulatory system. But they’re a classic model organism for studying aging and reproductive processes in biology because they do share many genes and molecular pathways that control development with humans.”

“They are also really useful because they have a short lifespan of about three weeks, so we can study them over several generations in a short amount of time. Doing a similar study in humans would take more than a century!”

It seems that older parents invested more energy in their eggs, giving their offspring a better start at growing larger and maturing faster. Ironically,  this allowed the offspring of older parents to become parents at a younger age and create more offspring. Dr. Travers explains the importance of this finding,

“It has often been suggested that old parental age is detrimental for offspring lifespan, health and fitness. But our results show that old parental age has strong beneficial effects for offspring development and lifetime reproductive success.This is really important because it contradicts the established view that old parental age invariably reduces offspring lifespan and fitness.”

The study is published in the journal Proceedings of the Royal Society B Biological Sciences.

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By Zach Fitzner, Earth.com Staff Writer