Journal Article
It’s time for dinner, a particular and seasonal feeding habit of a threatened troglobitic Catfish from Brazil, Rhamdiopsis krugi Bockmann and Castro 2010 (Ostaryophysi, Siluriformes)
Bichuette, M.E.
Record Number:
6803
Year:
2024
Journal:
Fishes
Pages:
1-19
Volume:
9, 494
Notes:
Copyright: © 2024 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons
Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)
Abstract:
Abstract: Rhamdiopsis krugi is a highly specialized troglobitic (exclusively subterranean) catfish endemic to the phreatic water bodies of twelve caves located within two separated metasedimentary basins in the region of Chapada Diamantina, Bahia state, Brazil. This species is included in the List of Endangered Fauna of Brazil, under the Vulnerable category—VU. In general, troglobites have different strategies for searching for food and reproductive partners, as well as unique behaviors. Knowledge of the reproductive periods, as well as its feeding habits, provides fundamental data for effective protection and species conservation. Biological aspects related to feeding habits and
reproduction of R. krugi were addressed across six annual cycles, considering both dry and rainy seasons. For this, stomach content analysis, using the frequency of occurrence and volumetric index methods, as well as observation of the sex ratio and stage of maturation of the gonads were carried out for 148 individuals of R. krugi sampled in eight caves in Chapada Diamantina. Stomach volumes correlated with reproduction aspects across the dry and rainy seasons. These populations showed opportunistic carnivorous feeding habits, consuming both autochthonous and allochthonous items, with a preference for foraging in submerged guano deposits, which demonstrates the catfish’s strong
dependence on bats. Regarding sex ratios, there was no marked seasonality; however, in rainy seasons, there was a higher proportion of maturing females, showing a reproductive tendency. During these periods, there was also a significantly higher number of stomachs with contents, showing seasonality in the diet. Specialized diet and dependence on rainy periods, especially in diet, corroborate the fragility of R. krugi, especially considering the changes in rainfall regimes in Brazil, with dry seasons exceeding eight months per year in the last ten years.
Keywords: cavefish; guano; reproduction; Heptapteridae; Chapada Diamantina; Bahia
Key Contribution: The study is a monitoring through six annual cycles, extremely rare when we consider cave organisms. It is shown that R. krugi did not follow the expected outcomes considering the sex ratio observed for most fish. Even more, R. krugi ingests great amount of bat guano together with invertebrates, and shows seasonality in reproduction, even occurring in habitats with few environmental oscillations, such as phreatic waters. These data are applicable for conservation purposes and show the importance of long-term ecological studies covering several annual cycles
Times Cited:
1
Relevent Species:
Related Records:
Trajano, E. (1993)
Considerations about systematics and the evolution of behavior in Siluriform cave fishes
Mendes, L.F. (1995)Observations on the ecology and behaviour of a new species of troglobitic catfish from northeastern Brazil (Siluriformes, Pimelodidae)
Trajano, E. and Menna-Barreto, L. (1995)Locomotor activity pattern of Brazilian cave catfishes under constant darkness (Siluriformes, Pimelodidae)
Trajano, E. (1997)Food and reproduction of Trichomycterus itacarambiensis, a cave catfish from south-eastern Brazil
Trajano, E. and Bockmann, F.A. (2000)Ecology and behaviour of a new cave catfish of the genus Taunayia from north-eastern Brazil (Siluriformes: Pimelodidae)
Britto, M.R., Lima, F.C.T. and Santos, A.C.A. (2005)A new Aspidoras (Siluriformes: Callichthyidae) from rio Paraguaçu basin, Chapada Diamantina, Bahia, Brazil
Ribeiro, AC (2006)Tectonic history and the biogeography of freshwater fishes from the coastal drainages of eastern Brazil: an example of faunal evolution associated with a divergent continental margin
Bockmann, F.A. and Castro, R.M.C. (2010)The blind catfishes from the caves of Chapada Diamantina, Bahia, Brazil (Siluriformes: Heptapteridae): description, anatomy, phylogenetic relationships, natural history and biogeography
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Trajano, E., Gallao, J.E. and Bichuette, M.E. (2016)Spots of high biodiversity of troglobites in Brazil: the challenge of measuring subterranean diversity
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Cardoso, G.M., Bastos-Pereira, R. and Ferreira, R.L. (2022)Two new troglobitic species of Iansaoniscus from Brazilian caves (Crustacea, Isopoda, Pudeoniscidae)
Bichuette, M.E. (2024)It’s time for dinner, a particular and seasonal feeding habit of a threatened troglobitic Catfish from Brazil, Rhamdiopsis krugi Bockmann and Castro 2010 (Ostaryophysi, Siluriformes)