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Vol. 51 No. 1, 2012
Feeding Habits and Trophic Niche Overlap of Aquatic
Orthoptera Associated with Macrophytes
Soledad
Capello1,*, Mercedes Marchese1,2, and María L. de
Wysiecki3
1Instituto
Nacional de Limnología (INALI-CONICET-UNL), Ciudad Univ., Santa Fe
3000, Argentina
2Facultad de Humanidades y Ciencias-UNL. Ciudad Univ.,
Paraje El Pozo, Santa Fe 3000, Argentina
3Centro de Estudios Parasitológicos y de Vectores
(CEPAVE) (CCT-La Plata- CONICET- UNLP), Calle 2 nº 584, La Plata 1900,
Argentina
Soledad Capello, Mercedes Marchese, and María L. de
Wysiecki (2012) A
dietary analysis is a frequent 1st step in studying an animal’s
ecology, because its diet directly reflects resource use and can
provide insights into habitat utilization and competitive interactions.
Little is known concerning orthopteran species that inhabit moist or
wet environments, because such species do not usually become pests. We
hypothesized that aquatic orthopterans feed on only a few macrophytes,
and they show trophic niche overlap. Feeding habits of 7 orthopteran
species associated with macrophytes, the botanical composition of the
diets of these insects, and their trophic niche breadth and overlap
were analyzed from the Middle Paraná River, Argentina. The diet
composition by a microanalysis of feces under an optical microscope and
the frequency of occurrence of each plant, food niche breadth, niche
overlap, and food specialization level of every species were
determined. Only Paulinia acuminata, Marellia remipes, and Cornops aquaticum exclusively consumed
aquatic plants. The water hy cinth (Eichhornia
crassipes) was the
unique macrophyte consumed by all orthopteran species studied, although
in different proportions. The greatest trophic niche breadth was shown
by Coryacris angustipennis,
and the highest Berger-Parker index value was found for C. aquaticum, which also showed
high specificity. The species C.
aquaticum, C. angustipennis,
Conocephalus sp., and Scudderia sp. showed niche overlap;
however, they can live in the same habitats because resources are very
abundant. This is the 1st analysis of the diet compositions of these
species (except C. aquaticum),
and it is important information to explain orthopteran assemblages
associated with macrophytes in this Argentine river.
Key words: Diet, Herbivores, Orthoptera,
Water hyacinth, Paraná River.
*Correspondence: E-mail:solecapello@gigared.com
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