When It Rains, Eggs Gain: Maternal Investment in Eggs and Progeny in Caiman

ABSTRACT

Environmental factors influence females and the resources they accumulate and invest in their eggs. We studied the influence of climatic variables and corporal attributes of Caiman latirostris females on egg characteristics, hatching success and hatchling size. We recorded reproductive metrics of female body and physiological condition, and collected their entire clutches. One group of the eggs in a clutch was assigned for fatty acid profile analysis (FA), while another was used for artificial incubation. We also registered the precipitation and temperature of previous reproductive season and prior to oviposition. Eggs from females with better body condition had a higher proportion of the essential fatty acid (EFA) C20:4 and higher polyunsaturated FA content. EFAs such as C20:4, C22:5, and C22:6 in eggs were positively associated with seasonal precipitation and temperature, suggesting that rainy years are beneficial for maternal investment. In contrast, C18:2 in eggs was negatively associated with precipitation during vitellogenesis but positively correlated with maternal tissue fatty acids. The high proportion of C18:2 may reflect a greater consumption of prey rich in C18:2, such as insects or mollusks, possibly associated with a less diverse diet resulting from changes in resource availability driven by climatic conditions during these periods. High C18:2 content in eggs was associated with lower hatching success. Therefore, years with abundant precipitation during vitellogenesis are advantageous because they may increase prey diversity and resource availability for females, allowing greater transfer of physiologically important fatty acids to eggs.