Temperature and immunity: temperature manipulation during embryonic development and its effect on the immune system and thermoregulatory performance 

Daniel Ardia

Franklin & Marshall College, USA

Developmental conditions during early life can have effects on physiology in later life history stages. Using temperature modifications during development, I have studied how developmental temperature affects organismal performance, including multiple measures of immune response. Temperature can drive physiological development through tradeoffs or can adjust developmental programming, such as through perinatal programming. The effect of temperature on performance is particularly critical in a period of rapid global warming. I present results from field and laboratory manipulations of embryonic temperatures on immunity and thermoregulation. Experimental cooling of tree swallow embryos led to long-term lower innate immunity measured as bacteria killing ability. Field temperature manipulation during embryonic development also affected thermoregulatory ability, with moderate cooling leading to improved thermoregulatory performance. In captive studies using artificial incubation, quail and zebra finches show effects of temperature manipulation on cell-mediated immunity, bacteria killing ability, white blood cell counts, metabolic rate and thermoregulation. In general, deviation from optimal embryonic development conditions leads to reduced immune activity in juveniles, but potential acclimatory performance in metabolic rate and thermoregulation. These results suggest that embryonic development conditions in birds can have complex developmental effects on immunity, thermoregulatory performance and metabolic rate.