Meeting Abstract
Environmental temperature is a driving force in ectothermic physiology and is a limiting resource in temperature habitats. We examined the sprint speed and innate immune ability of Hemidactylus turcicus across a thermal gradient to determine this species’ thermal optimum and potential thermal plasticity. The effects of dietary n-3 PUFAs on immune performance were also tested, because these essential nutrients are suspected to be a limiting factor in some aspects of immunity. Adult H. turcicus were collected from buildings in southern Illinois following the breeding season and maintained in captivity. Sprint speed was recorded across a thermal gradient from 20–36oC in 4oC intervals, which represented both the extremes and optimal temperatures for this species. Innate immune performance was also tested along a thermal gradient from 20–35oC in 5oC intervals, by injecting H. turcicus with PHA extracts in their rear foot and measuring the swelling response. Geckos were then orally dosed with n-3 PUFAs or water and the PHA experiments were conducted again at 25 and 35oC. As expected, sprint speed increased with temperature but plateaued at 28–36oC, and the swelling response to PHA exhibited a similar increase with temperature. These results show that H. turcicus exhibits high thermal plasticity as they are able to maximize physiological performance across a range of temperatures. N-3 PUFAs supplements induced a significant and complex interaction between innate immunity and temperature; whereby geckos orally dosed with n-3 exhibited an increased swelling response to PHA at 25oC, compared to controls, but a strong reduction in swelling at 35oC. Controls did not change with temperature. While previous studies have shown that n-3 PUFAs are associated with immunomodulatory effects, our results suggest n-3 PUFAs can also have complex, temperature dependent anti-inflammatory affects.
