Abstract
The amphipod Quadrivisio lutzi (Shoemaker, 1933) (Maeridae) inhabits the coastal lagoons of southeastern Brazil, which are highly unstable environments. Drastic reduction in the abundance and distribution of this amphipod on these lagoons has been observed. The constant recovery of its populations suggests that this species may show a reproductive strategy that helps it to persist on these environments. Therefore, our aim was to study the reproductive biology of this species in Carapebus lagoon and to answer the question if its reproductive strategy contributes to a rapid population recovery. The size-range at sexual maturity was determined by the relative growth of the gnathopods and by the number of articles in antennal flagella. Brood size, egg diameter, size at first maturity and other relative reproductive parameters were obtained, which were compared to other species using a multivariate Principal Component Analysis (PCA). Females reach maturity at smaller size-range (2.9-3.9 mm body length (BL) than males (4.9 -5.9 mm BL). Mean egg diameter was small (0.35 ± 0.08 mm) and fecundity was high (20.2 ± 9.2 eggs/female; maximum 48 eggs). The relative reproductive parameters observed in Q. lutzi suggest it as iteroparous species. The PCA situated Q. lutzi within the species of high reproductive potential, characterized by small female size at first maturity, small egg diameter, large brood size and iteroparity, which have been largely considered adaptations that allow rapid recovery of population sizes. Therefore, we concluded that the reproductive strategy of this species contributes to its survival in the highly unstable Carapebus lagoon at southeastern Brazil.
Highlights
The amphipod Quadrivisio lutzi (Shoemaker, 1933) (Maeridae) inhabits coastal lagoons in the southeast of Brazil (Leite et al, 1980; Henriques-de-Oliveira et al, 2007; Weber et al, 2013), which are environments characterised by high humic acid content
Maturity and sexual dimorphism Changes in the relative growth of the propodus of the second gnathopod and in the number of flagellum articles were evident in both sexes, at 0.3 mm head length (HL) (2.9 – 3.5 mm body length (BL)) in females (Fig. 6) and at 0.5 mm HL (4.9 – 5.9 mm BL) in males (Fig. 7)
Changes in the relative growth of the propodus of the gnathopods and in the number of articles in antennal flagella have been previously studied in other amphipods to relate them either with growth phases, sexual dimorphism or size at maturity (Leite and Wakabara, 1989; Moore and Wong, 1996; Lopes and Masunari, 2004; Tsoi and Chu, 2005)
Summary
The amphipod Quadrivisio lutzi (Shoemaker, 1933) (Maeridae) inhabits coastal lagoons in the southeast of Brazil (Leite et al, 1980; Henriques-de-Oliveira et al, 2007; Weber et al, 2013), which are environments characterised by high humic acid content (see Farjalla et al, 2002; 2009) This species has colonised freshwater environments (Lee and Bell, 1999) and is an important component of the trophic chain of these aquatic ecosystems, primarily as a decomposer of bottom vegetal debris and as a consumer of animal organic litter. Some of the lagoons are subject to contamination with anthropogenic waste and/or domestic sewage (Henriques-de-Oliveira et al, 2007; Esteves, 2011)
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