Sexual size dimorphism of the freshwater shrimp Macrobrachium jelskii (Miers, 1877) (Decapoda: Palaemonidae) and its relationship to Rensch’s rule

Population structure and fecundity of Macrobrachium jelskii (Miers, 1877) (Decapoda, Palaemonidae) on the Batateiras River, sub-basin of the Salgado River, in southern Ceará, Brazil

“…In M. jelskii, males probably exhibit "pure search" behavior with no need for a large body size and may reach sexual maturity at smaller sizes. The females of M. jelskii, on the other hand, probably prioritize a larger body size (Nascimento et al, 2020), since an increase in fertility is directly related to growth of the body, as observed in our results and by other authors (Nery et al, 2015;Soares et al, 2015). (Miers, 1877).…”

“…The sexual size dimorphism found in the present study, where females are morphometrically larger than males, is widely known for M. jelskii (Barros-Alves et al, 2012;Rocha and Barbosa, 2017;Taddei et al, 2017a;Silva et al, 2019a;Nascimento et al, 2020). This pattern can be explained by the evolution of reproductive strategies for M. jeslkii.…”

“…This pattern can be explained by the evolution of reproductive strategies for M. jeslkii. Probably, the selection of female fecundity is associated with the strategy of "pure search" by males of these species (Nascimento et al, 2020). Corroborating our results of sexual size dimorphism and morphological sexual maturity, we can highlight the absence of males in the largest size classes for the population studied, as well as the greater abundance of ovigerous females in the largest size classes.…”

“…The higher abundance of M. jelskii males in our results may be related to their reproductive biology, especially in the rainy months. If males exhibit the "pure search" behavior, as proposed by Nascimento et al (2020), they are more active and consequently more exposed in these months, when females are more receptive to mating. In addition, females, especially when ovigerous, use macrophytes from marginal areas as a refuge (Montoya, 2003;Soares et al, 2015), reducing their capture probability.…”

Inter‐sexual comparison of body biomass, proximate biochemical composition, and fatty acid profiles of new juvenile squat lobsters (Pleuroncodes monodon) in the Southeast Pacific Ocean

“…These physiologically adaptive processes have probably led to a sexual differentiation in size early in the juvenile stage in the red squat lobster (Guerao & Abelló, 2011;Haye et al, 2010). Similar responses have been described in other marine decapod crustaceans (e.g., Aristaeomorpha foliacea, Belcari et al (2003); Macrobrachium jelskii, Nascimento et al (2020)).…”