INBIOSUR   25013
INSTITUTO DE CIENCIAS BIOLOGICAS Y BIOMEDICAS DEL SUR
Unidad Ejecutora - UE
artículos
Título:
The influence of energy, nutritional value and noxiousness of prey in sex- and size-biased predation by Snail Kites in southern South America
Autor/es:
CADIERNO, PILAR; MARTÍN, PABLO RAFAEL; BURELA, SILVANA; HERAS, HORACIO; DREÓN, MARCOS
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 biochemical composition exhibited significant differences between sexes. Proteins and carbohydrates were the major energy-providing components. 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, determined at foraging perches sampled monthly, showed that Kites preferentially feed always on the largest snails available throughout the sampling period. In spite of the fact that the remains of female body without the AG have less energy than males, sex preferential predation toward females was observed.Our study demonstrates for the first time the optimal foraging trade-off between prey size/sex and nutrition/energy in Snail Kites. After discarding the albumen gland, male and female snails of equivalent size provide different nutrients and energy, though Snail Kite foraging is generally biased toward females mostly due to their bigger size suggesting Snail Kites are unable to distinguish between sex. , , , , .