Reproductive behavior, development and eye regression in the cave armored catfish, Ancistrus cryptophthalmus Reis, 1987 (Siluriformes: Loricariidae), breed in laboratory

Abstract

The parental care by the male, which includes defense of the rock shelter where the egg clutch is laid, cleaning and oxygenation of eggs, is typical of many loricariids. On the other hand, the slow development, including delayed eye degeneration, low body growth rates and high estimated longevity (15 years or more) are characteristic of precocial, or K-selected, life cycles. In the absence of comparable data for close epigean relatives (Ancistrus spp.), it is not possible to establish whether these features are an autapomorphic specialization of the troglobitic A. cryptophthalmus or a plesiomorphic trait already present in the epigean ancestor, possibly favoring the adoption of the life in the food-poor cave environment. We briefly discuss the current hypotheses on eye regression in troglobitic vertebrates.O cascudo troglóbio (exclusivamente subterrâneo), Ancistrus cryptophthalmus (Loricariidae, Ancistrinae) é conhecido de quatro cavernas na área cárstica de São Domingos, bacia do alto rio Tocantins, Goiás. Estas populações diferem quanto ao formato geral do corpo e grau de redução dos olhos e da pigmentação cutânea. A pequena população encontrada na caverna Passa Três (aproximadamente 1.000 indivíduos) é a que apresenta os olhos mais reduzidos, não visíveis externamente nos adultos. Um grupo de um macho e três fêmeas provenientes dessa caverna reproduziu-se espontaneamente três vezes em laboratório, no fim do verão, O cuidado parental pelo macho, que inclui defesa do abrigo rochoso onde os ovos eram aderidos e limpeza e oxigenação destes, segue o padrão típico de loricariídeos. Por outro lado, o desenvolvimento relativamente lento, incluindo a regressão tardia dos olhos (iniciando aos 12 meses de idade), as baixas taxas de crescimento corporal e a alta longevidade estimada (mais de 15 anos) são característicos de ciclos de vida do tipo "precoce", ou K-selecionados. Na ausência de dados comparáveis para os aparentados epígeos próximos, não é possível estabelecer com exatidão se tais características se tratam de adaptações autapomórficas da espécie cavernícola ou de pré-adaptações (exaptações) dos ancestrais epígeos, as quais poderiam ter favorecido a colonização do meio subterrâneo. Finalmente, apresentamos uma breve discussão sobre as hipóteses correntes acerca da regressão dos olhos em vertebrados troglóbios.

Ecological and phylogenetic determinants of life‐history patterns among ten loricariid species

“…The remaining two of the five subfamilies of Loricariidae ( sensu Roxo et al ., ) for which life‐history data exist also show one predominant life‐history strategy. On one side, the Ancistrinae consistently shows characteristics concordant with an equilibrium strategy (Secutti & Trajano, ; Suzuki et al ., ) and on the other side the Rhinelepinae exhibits an extreme periodic strategy (Suzuki et al ., ). In this way, our study supports the hypothesis that phylogenetic history is more important in the determination of life‐history strategies than key ecological factors.…”

“…This pattern of life‐history conservationism within subfamilies is in agreement with previous reviews of the reproductive strategies of the Loricariidae (Agostinho et al ., ; Secutti & Trajano, ; Suzuki et al ., ). The remaining two of the five subfamilies of Loricariidae ( sensu Roxo et al ., ) for which life‐history data exist also show one predominant life‐history strategy.…”

“…> 2500 g in Hypostomus commersoni Valenciennes 1836), fecundity (less than 50 oocytes in Ancistrus cryptophthalmus Reis 1987 v . more than 180,000 oocytes in Rhinelepis aspera Spix & Agassiz 1829 (Secutti & Trajano, ; Suzuki et al ., )) and oocyte size among species (Secutti & Trajano, ). Recently, interest in the reproduction of loricariids has increased as a result of the numerous cases of rapidly spreading invasions by several species of this family in tropical and subtropical environments around the world (Hoover et al ., ; Orfinger & Goodding, ).…”

Reproduction, development, asymmetry and late eye regression in the Brazilian cave catfish Ituglanis passensis (Siluriformes, Trichomycteridae): evidence contributing to the neutral mutation theory

“…Over the last seven decades and among fishes, Mexican tetra characins of the genus Astyanax have been the favored source of material in genetic and developmental studies focused on the regression of eyes and pigmentation in cave derivatives (e.g., Thinès 1960;Wilkens 1971Wilkens , 1987Wilkens , 1988Wilkens , 2007Wilkens , 2011Peters and Peters 1973;Durand 1979;Borowsky and Wilkens 2002;Jeffery 2005;Gross et al 2009;Yamamoto et al 2009;Bilandzija et al 2013;Hinaux et al 2013;McGaugh et al 2014;Wilkens and Strecker 2017; among many others). The other troglobitic fishes studied include the cyprinids Caecobarbus geertsi (Thinès 1960), Phreatichthys andruzzi (Berti et al 2001;Aden 2008) and Garra barreimiae (Aden 2010), besides the Brazilian loricariid, Ancistrus cryptophthalmus (Secutti and Trajano 2009). In every case, juveniles were born with apparently normally structured eyes, that degenerated throughout ontogeny.…”

“…The reproductive cycles of relatively few among the 200+ troglobitic fishes worldwide have been described. Among these, the Mexican cave-fishes Astyanax (e.g., Wilkens 1987Wilkens , 1988Parzefall 1993;Jeffery 2005), the USAn amblyopsids (Poulson 1963), and the Brazilian armored catfish Ancistrus cryptophthalmus (Secutti and Trajano 2009) based on spontaneous (non-induced) reproduction in the laboratory, the Mexican heptapterids Rhamdia zongolicensis and R. reddelli (Wilkens 2001), and Phreatichthys andruzzi from Somalia (Berti et al 2001;Aden 2008) based on induced reproduction, and the Cuban bythitid Lucifuga subterranea (Durand 1998) based on data from the natural habitat.…”