Reproductive biology and development of gill glands in the inseminating characid, Macropsobrycon uruguayanae Eigenmann, 1915 (Cheirodontinae: Compsurini)

Abstract

Reproductive biology and development of gill glands in the inseminating characid, Macropsobrycon uruguayanae Eigenmann, 1915

Reproductive ecology of Odontostilbe pequira (Steindachner, 1882) (Characidae, Cheirodontinae) in the Paraguay River, southern Pantanal, Brazil

“…Since O. pequira shows a long reproduction, it is possible to suppose that the females have a high reproductive investiment, spawning several batches the whole year, which also compensates for the apparently low fecundity. The diameter of O. pequira oocyte was smaller than observed in Cheirodontinae Macropsobrycon uruguayanae (Azevedo et al 2010) and also in most of Characidae species (Kramer 1978), suggesting that the small diameter is one more attempt to increase fecundity, which is lower in relation to other Cheirodontinae fish.…”

“…The absolute fecundity of O. pequira was low (181.4) in relation to the fecundity (795) found for the same species in southern Brazil (sub-tropical region) (Oliveira et al 2010), as for other Cheirodontinae fishes with external fertilization (Gelain et al 1999;Oliveira et al 2002;Silvano et al 2003), although such works report on seasonal reproductive periods. This behavior appears clear, because the fecundity of the inseminating Cheirodontinae Macropsobrycon uruguayanae was shown to have a similar value (191.08 oocytes) (Azevedo et al 2010), which could be a viable tactic among the Cheirodontinae fishes, which have a long reproductive period, independent of the type of fertilization. However, the relative fecundity of O. pequira (0.54) is similar to that of various Cheirodontinae fishes, such as Macropsobrycon uruguayanae (0.53) and Cheirodon ibicuhiensis (0.5), and smaller than the value found for the species in southern Brazil, which was the highest found for Cheirodontinae fishes to date (0.80) (respectively: Azevedo et al 2010;Oliveira et al 2002Oliveira et al , 2010.…”

“…This behavior appears clear, because the fecundity of the inseminating Cheirodontinae Macropsobrycon uruguayanae was shown to have a similar value (191.08 oocytes) (Azevedo et al 2010), which could be a viable tactic among the Cheirodontinae fishes, which have a long reproductive period, independent of the type of fertilization. However, the relative fecundity of O. pequira (0.54) is similar to that of various Cheirodontinae fishes, such as Macropsobrycon uruguayanae (0.53) and Cheirodon ibicuhiensis (0.5), and smaller than the value found for the species in southern Brazil, which was the highest found for Cheirodontinae fishes to date (0.80) (respectively: Azevedo et al 2010;Oliveira et al 2002Oliveira et al , 2010. Despite the intraspecific difference in relative fecundity, O. pequira in the southern Pantanal demonstrates GSI values comparable to those found by Oliveira et al (2010), indicating an equivalent reproductive investment, in view of the long reproductive period and lower fecundity observed here versus seasonal reproduction and greater fecundity in southern Brazil (subtropical region).…”

Comparative local analysis of metabolites, lipids and proteins in intact fish tissues by LAESI mass spectrometry

“…34,35 Both light and transmission electron microscopy demonstrated the presence of secretory vesicles in the columnar cells lining the gill gland. On occasion, periodic acid-Schiff stained (PAS+) material was observed within the lumina of the gill gland chambers (see the PAS+ stained regions in Fig.…”

“…2). [34][35][36] Due to the secretory nature of gill glands and their development as male secondary sex characters, it was hypothesized that these structures might release some type of male sexual chemical signal or pheromone. …”