Meeting Abstract

P3.83  Saturday, Jan. 5  Control of salt gland secretion in two insectivorous lizard species HAZARD, L.C.**; LECHUGA, C.; ZILINSKIS, S.; Montclair State University, NJ; Montclair State University, NJ; Montclair State University, NJ hazardl@mail.montclair.edu

When dietary salt content is high, some reptile species rely on cranial salt glands to supplement renal ion excretion. The salt glands of lizards are unique among reptiles in their ability to secrete potassium and bicarbonate in addition to the more typical sodium and chloride. Composition of the secreted fluid depends on the ion load incurred: herbivorous lizards generally secrete potassium chloride, while marine species secrete primarily sodium chloride. Many insectivorous species also possess salt glands but have been minimally studied. We studied secretion by the nasal salt glands of two insectivorous lizard species, Novoeumeces schneideri (Scincidae) and Anolis carolinensis (Polychrotidae) in response to different combinations of cations (sodium, potassium, and histidine control) and anions (chloride and acetate control). Lizards were injected with ion solutions or controls (saline and sham injected) daily for 4 days; secreted salt, feces and urine were collected daily. Samples were analyzed for sodium, potassium, and chloride and daily cation and anion secretion rates calculated. The salt glands of Anolis secreted only in response to chloride, regardless of the accompanying cation. Novoeumeces also secreted in response to chloride, but secreted at higher rates when histidine or potassium were also present. Both species showed low variation in cation secretion; Anolis secreted almost entirely potassium, even when given sodium loads, while Novoeumeces secreted a mix of the two regardless of cation load. The responses of these two species differ from each other and from two herbivorous species studied previously, indicating considerable flexibility in the physiology of the salt gland across lizard taxa.