INVESTIGADORES
RUEDA MARTIN Paola Alejandra
artículos
Título:
Trophic analysis of three species of Marilia (Trichoptera: Odontoceridae) from the neotropics
Autor/es:
REYNAGA, M. CELINA; RUEDA MARTÍN, PAOLA ALEJANDRA
Revista:
REVISTA DE BIOLOGÃA TROPICAL
Editorial:
REVISTA DE BIOLOGIA TROPICAL
Referencias:
Lugar: Turrialba; Año: 2014 vol. 62 p. 543 - 550
ISSN:
0034-7744
Resumen:
The trophic ecology of the aquatic insect fauna has been widely studied for the Northern temperate
zone. However, the taxa originally classified within a given particular trophic group in temperate ecosystems,
do not necessarily exhibit the same dietary profile beyond its geographic limits. Since, the trophic ecology
of caddisfly larvae is largely incomplete in the Neotropical Region, the present work aims to describe feeding
habits inferred from quantitative analysis of data taxonomically resolved at the species level. For this, the
feeding habits of three Trichoptera species Marilia cinerea, M. elongata and M. flexuosa were recorded in the
Yungas forests of Argentina and Bolivia. A total of 15 larvae of each species were sampled from 13 different
streams were selected for gut content analysis. The ingested material was extracted from the foregut and midgut
by using ventral dissection of thorax. For each species, mandibles were dissected, mounted in glycerin and
illustrated in order to highlight morphological differences between these mouth pieces purportedly associated
to the dietary behavior of individuals, and their habitats. The niche overlap was estimated through Schoener?s
method. The diet analysis revealed that M. cinerea, M. elongata and M. flexuosa feed on the same food items,
but through different patterns of preferences. Larvae of M. cinerea were collected on both emerging surfaces of
rocks on which a thin layer of running water flows and streams sliding areas with stony bottoms attached to the
rock surfaces. They displayed a gut content consisting predominantly of invertebrate vestiges and have strong
mouthparts provided of large molar areas; this allowed us to allocate the species within the functional group of
predators. M. elongata feeds mainly on fine particulate material, its mouthparts are scoop-shaped and occurs
in areas of low flow; this set of features is linked to a collector-gatherer strategy. Finally, larvae of M. flexuosa
have been primarily assigned to the functional group of shredders and secondarily to the collector-gatherer
class. They inhabit sandy bottoms of mountain streams, have strong scoop-shaped mouthparts and show a diet
dominated by leaf litter and fine particulate material. We concluded that the functional group assignment to the
genus level for Marilia is not recommended, and further studies at species level are necessary.