Lizards may be overwhelmed by fire ants and social stress combined

Date: May 23, 2017

Source: Penn State

Lizards living in fire-ant-invaded areas are stressed. However, a team of biologists found that the lizards did not exhibit this stress as expected after extended fire ant exposure in socially stressful environments, leading to questions about stress overload. "After encounters with non-lethal stress levels (from fire-ant exposure), we asked; Okay, they (the lizards) live, but what happens then?" said Tracy Langkilde, professor of biology, Penn State. "Do they live and are fine? Do they live and remain stressed? We just don't know."

Langkilde and her colleagues wanted to know the short- and long-term physiological effects on fence lizards due to invading fire ants. Langkilde's prior research showed that lizards in fire-ant-invaded areas have elevated stress levels in their natural habitats, but did not pinpoint the cause of that stress.

"We can't look at lizards in the field," said Langkilde, "because the environments aren't controlled and so we can't assume that the stress response is just due to the fire ants. There are other environmental factors that could be causing differences in stress." The researchers conducted two experiments to test fence lizards' stress response to non-lethal exposure to fire ants. The first experiment looked at the impact on stress physiology immediately after a short, fire-ant exposure and the second looked at the physiological effects after extended exposure in semi-natural conditions.



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