Meeting Abstract
Steroid hormones are considered mediators of life history stages in vertebrates, due to their broad effect on animal physiology and behavior. For seasonal species, there is an increase in androgens (T), estradiol (E) and glucocorticoids (GC) during reproductive season, which allows and facilitates this process. These steroids also display complex immunomodulatory effects, which depends on hormonal concentration, temporal pattern and individual condition. We are investigating the seasonal covariation of steroid levels (T, E, GC), immune parameters (leukocyte profile and bacterial killing ability) and body condition index in males and females of the tegu lizards (Salvator merianae), a species that display pronounced transitions in life history stages along the year. We expect immunity to be positively correlated with steroids and body condition during reproductive phase, and lower immunocompetence during hibernation compared to the rest of the year. Considering the differential investments in reproduction among males and females, we also expect to found differences on immunity among sexes. The links between of season, sex, body condition index, hormone levels, and immunological parameters will be tested.
