The key to success for invasive species: die young

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The key to a successful invasion may lie in living fast and dying young. University of Iowa biologists studying a species of freshwater snail found that lines that were the most effective invaders matured and reproduced faster than their non-invasive counterparts within the species. Credit: Carina Donne, Colorado State University

Key points:

  • Asexual snails have been successful invasive species, despite their low genetic diversity.
  • For invasive species, there is a major advantage to the combination of slow growth rate and early reproductive maturity.
  • The measure of a species’ reproductive success could potentially be used to predict which species would make good invaders, allowing for early prevention measures.

Researchers at the University of Iowa have found that “live fast and die young” may not just be rap lyrics. For invasive species, the motto is actually a successful lifestyle.

In a new study published in Ecology, the research team examined why a type of freshwater snail that has invaded ecosystems around the world has been so successful. The studied freshwater mud snails are native to New Zealand and have spread – probably beginning with commercial shipping – to dominate many lake and river ecosystems in Asia, North America, Europe and elsewhere. Species are of interest to biologists because they reproduce both sexually and asexually.

Asexual snails were the most effective invaders, despite much lower genetic diversity than sexual snails. Additionally, asexual snails have slower growth rates – and are smaller in size – than sexual snails. While this combination would generally reduce a species’ ability to compete in a new setting, the reverse has happened.

To understand why, the team of researchers developed populations of snails originally collected in Belgium and six locations across the United States in their lab. They examined the offspring for “life history traits”, that is, characteristics related to an organism’s fitness or reproductive success that would allow it to thrive in a new environment.

“They grow significantly faster than their New Zealand counterparts,” said Carina Donne, corresponding author of the study and a PhD student at Colorado State University. “It just shortens the whole life cycle. If you can make babies at a younger age, all other things being equal, your populations will grow faster.

“I think the data suggests that there seems to be a real benefit to this combination of slow growth rate and early reproductive maturity,” said Maurine Neiman, lead study author and professor at the University of ‘Iowa. “Their generation times are faster and they are likely to outperform other snail lines that mature more slowly.”

Beyond a successful strategy for an invasive species, the researchers say the study results shed light on the importance of life history traits. They think life history traits could be fundamental to knowing if and how other species take root in new environments.

“Much research on invasive species focuses on prevention measures. We have so many invasive species that once they’re there and established, it’s harder to get rid of them,” Neiman said. “If we can figure out a way to predict what the right invasive species would be, we could implement preventative measures.”

Data provided by the University of Iowa.

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