INIBIOLP   05426
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE LA PLATA "PROF. DR. RODOLFO R. BRENNER"
Unidad Ejecutora - UE
artículos
Título:
The influence of energy, nutritional value and noxiousness in sex- and size-biased predation by Snail Kites in southern South America
Autor/es:
BURELA,S.; HERAS, H.; CADIERNO, M.P.; MARTÍN, P.R.; DREON MS,
Revista:
EMU
Editorial:
CSIRO PUBLISHING
Referencias:
Lugar: Collingwood; Año: 2017 vol. 117 p. 382 - 387
ISSN:
0158-4197
Resumen:
Snail Kites (Rostrhamus sociabilis) feed almost exclusively on Apple Snails (Pomacea spp.). While field observations indicate they discard the noxious albumen gland (AG) when feeding on female snails, there is no information on the energy lost by this behavior, the gland composition, or if there are snail sex preferences associated. We addressed for the first time these aspects for Snail Kites foraging on Pomacea canaliculata in southern South America. Whole snail?s proximal composition exhibited significant differences between sexes. Proteins and carbohydrates were the major energy-providing components and soft parts provide ~2.91±0.16 and 2.50±0.14 Kcal g-1 dw for male and female without AG, respectively while AG accounts for 15 % of available energy.Size and sex of prey consumed were determined at foraging perches sampled monthly. Kites preferentially feed on larger snails compared with the population size distribution. In spite that the remains of female body without the AG have less energy than males, sex preferential predation toward females was observed.As whole, results indicate that after discarding the albumen gland, male and female snail of equivalent size provide different nutrients and energy, and that although Snail Kite predation is generally biased toward females this is due mostly to their bigger size.