Effect of nest inundation on the hatching success of Caiman latirostris eggs.

CEDILLO LEAL, C. ; SIMONCINI, M.; LEIVA, P.; LARRIERA, A.; PIÑA, C. I.

Skukuza

Congreso; 24th Working meeting Crocodile Specialist Group/UICN; 2016

Internationa Union Conservation of Nature/Crocodile Specialist Group

Inundationis one of the main causes of poor hatching success in crocodilians, howeverthere is little information about the tolerance of embryos to submergence andthe role that eggshell structure has on embryo survival.  The objective of this research was todetermine the effect of inundation on hatching success of Caiman latirostris eggs flooded at two stages of embryonicdevelopment and whether eggshell surface roughness influences the tolerance ofembryos to inundation. We used clutches from 10 nests, separated into twogroups of five clutches; eggs of each clutch were divided into four treatments (nineeggs per treatment) as follows: 1. Non-inundated without scraping eggshell; 2. Non-inundatedwith scraping eggshell; 3. Inundated without scraping eggshell; 4. Inundated withscraping eggshell. A group of five clutches was inundated when each clutch reachedday 30 of development (at 32°C±0.5°C), whereas another group of five clutches wasinundated when they reached day 60 of development.  All inundated groups were immersed for aperiod of 10 hours. At day 30 of embryo development (at 32°C±0.5°C), inundationonly reduced hatching success in scraped eggs. On the other hand, at day 60 of embryodevelopment, inundation decreased hatching success in both groups (with orwithout scraping eggshell surfaces). We conclude that eggshell roughnessmitigate the damage caused by early inundation. On the other hand, lateinundation tend to be fatal independently of eggshell roughness.