July 4, 2013
For Some Young Lizards, Their First Meal Is A Real Life Changer
Brett Smith for redOrbit.com - Your Universe Online
We have all heard of 'formative years' that can influence a person's view of the world and, consequently, their behavior - but a new study published in the journal Cell Biology has found for certain lizards their very first meal can have lasting impacts on everything from their future range to agility.
"A mere detail in life can make all the difference for the fate of individuals," said co-author Manuel Massot of Universite Pierre et Marie Curie in Paris. "Consequently, minor environmental variations can also influence evolution."
Referring to the phenomenon as "phenotypic response," Massot and the study's other co-author Pedro Aragon said they expect to see major significance attached to seemingly small events that take place particularly early on in life.
In the study, the researchers examined the viviparous lizard, or Zootoca vivipara. The lizard is unique because it gives birth to its young live, instead of laying eggs as most lizards do. After being born, the baby lizard must catch its first meal alone because adult Zootoca do not care after their young.
"The first meal of life is a great challenge for them, and it is for this reason that we expected that a single meal can condition a good start in life," Massot said.
The researchers began by capturing 120 pregnant lizards and having them give birth in their lab. Half of the newborns were given an easy first meal, while the other half were dropped into nature to fend for themselves - as they typically would without human interference. After eating, the lizards were placed back out into their natural habitat and recaptured periodically over two years to track their health outcomes.
The team's findings suggested the lizards' first meal had a momentous impact of later outcomes. Lizards that had been fed as newborns were more likely to remain in the same general area. They were also more difficult to catch and less often recaptured, the researchers said, adding that these outcomes could be due to "a greater ability to escape, lower activity, or reduced risk-taking behavior."
Meanwhile, the lizards that had to fend for themselves gave birth to larger litters two years later, averaging 4.3 births compared to 2.9.
The two biologists said the study's findings could have implications for other organisms. They recommended other biologists investigate seemingly minor events that can push species in unpredictable directions.
According to Massot's personal website, the ecologist is also involved in investigating the effects of global warming on species adaptation. His previous research has included studies on the reproductive habits of other European lizards and reptile adaptation to the effects of climate change.
Growing around a foot in length, Zootoca live throughout Europe and Asia. They can vary widely in color and patterning, but are typically medium brown, grey, or black.
The lizards typically mate in April and May - giving birth to three to ten young in July. The newborn lizards are a little longer than one inch when born and eventually they reach sexually maturity around 2 years old for males and 3 years old for females.