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Vol. 53, 2014
Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura:
Trichodactylidae) at La Plata basin
Verónica
Williner1,2*, Debora Azevedo Carvalho1 and Pablo
A Collins1,3
1Instituto
Nacional de Limnología (CONICET-UNL), Ciudad Universitaria, Paraje El
Pozo s/n, Santa Fe 3000, Argentina
2Facultad de Humanidades y Ciencias (UNL), Ciudad
Universitaria, Paraje El pozo s/n, Santa Fe 3000, Argentina
3Facultad de Bioquímica y Ciencias Biológicas (UNL),
Ciudad Universitaria, Paraje El pozo s/n, Santa Fe 3000, Argentina
Abstract
Background: In inland water
systems, it is important to characterize the trophic links in order to
identify the ‘trophic species’ and, from the studies of functional
diversity, understand the dynamics of matter and energy in these
environments. The aim of this study is to analyze the natural diet of Trichodactylus kensleyi of subtropical rainforest
streams and corroborate the temporal variation in the trophic activity
during day hours.
Results: A total of 15 major taxonomic groups were
recognized in gut contents. The index of relative importance identified
the following main prey items in decreasing order of importance:
vegetal remains, oligochaetes, chironomid larvae, and algae. A
significant difference was found in the amount of full stomachs during
day hours showing a less trophic activity at midday and afternoon. The
index of relative importance values evidenced the consumption of
different prey according to day moments. Results of the gut content
indicate that T. kensleyi is
an omnivorous crab like other trichodactylid species. Opportunistic
behavior is revealed by the ingestion of organisms abundant in streams
such as oligochaetes and chironomid larvae. The consumption of
allochthonous plant debris shows the importance of this crab as
shredder in subtropical streams. However, the effective assimilation of
plant matter is yet unknown in trichodactylid crabs.
Conclusions: This research provides
knowledge that complements previous studies about trophic relationships
of trichodactylid crabs and supported the importance of T. kensleyi in the transference of
energy and matter from benthic community and riparian sources to
superior trophic levels using both macro- and microfauna.
Key words: Decapoda; Omnivorous crab;
Shredder; Subtropical forest; Streams.
*Correspondence: E-mail: vwilliner@inali.unl.edu.ar
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