Relative growth and population dynamics of Macrobrachium iheringi (Decapoda, Palaemonidae)

Abstract

During the ontogenetic development of crustaceans, the relative growth of some structures may change, especially during the transition from juvenile to adult. This study describes the relative growth of body structures of Macrobrachium iheringi, and provides information on its population dynamics, such as structure, fecundity, and morphological sexual maturity. The sampling of M. iheringi was carried out in “Ribeirão da Hortelã”, in Botucatu (SP, Brazil). The length of the carapace (CL), abdomen (AL), and ischium (IL), merus (ML), carpus (CrL), propodus (PpL), and dactyl (DcL) of the second right pereopod were measured. In addition, the width of the second abdominal pleura (PW) and propodus height (PpH) were included in analyses. The relationships that best demonstrated the changes in the allometric coefficient were CL vs PpL in males and females. The CL, in which males and females reach morphological sexual maturity, was estimated as 13.3 mm and 11.1 mm, respectively. The sex-ratio differed from the expected 1:1 and was skewed towards females. Precipitation and temperature influenced the abundance of different demographic classes. Macrobrachium iheringi has few but large eggs, which is expected since this species has an abbreviated larval development. Based on these results, we conclude that the propodus are good indicators of the size at onset of morphological sexual maturity. In addition, important information was obtained on the biology of M. iheringi, including its life cycle pattern, reproduction and influence of abiotic factors.

Male morphotypes of the freshwater prawn Macrobrachium brasiliense (Decapoda: Caridea: Palaemonidae)

“…Moraes‐Riodades and Valenti () suggested that the occurrence of morphotype differences s could be a characteristic of the genus Macrobrachium , and that this hypothesis could only be confirmed upon the examination of more species, because there are hundreds of species in the genus Macrobrachium . According to the current literature, M. iheringi ( Ortmann 1897) (Nogueira et al, ) and some populations of M. amazonicum from water reservoirs (e.g., Pantaleão et al, ; Paschoal, Oliveira, Andrioli, & Zara, ) do not seem to show this characteristic. Some species or populations may lack the differentiation, because differentiation may be driven by the production of peptides by the androgenic glands and regulated by other factors associated with the endocrine physiology of these animals (Paschoal & Zara, ; Rocha & Barbosa, ).…”

Seasonal variation in the population structure of the freshwater prawn Macrobrachium brasiliense (Decapoda: Palaemonidae) in a neotropical region

“…The frequency distribution of males and females of M. brasiliense between the size classes followed a pattern, with a greater number of females in the smallest size classes and a greater number of males in the largest classes, which may be a reflection of the reproductive strategy called "temporary female guarding" (Bauer, 2004), with dominant males that court and protect females during copulation. This model of population structure seems to be a pattern in M. brasiliense, considering all the populations studied so far (Mantelatto and Barbosa, 2005;Pereira and Chacur, 2009;Oliveira et al, 2019), as well as for other Macrobrachium species (Mattos and Oshiro, 2009;Gualberto et al, 2012;Nogueira et al, 2019b;Perroca et al, 2021). Therefore, this type of sexual system appears to be common within the genus, since most populations are characterized by males being larger than females, with males showing aggressive behavior during social interactions (Fielder and Lee, 1983;Karplus et al, 1992;Karplus and Barki, 2019).…”

“…The hypothesis that rainfall seasonality should affect population structure and reproduction leading to peak recruitment in the dry season was tested. This hypothesis is supported by the theory of upward (bottom-up) and downward (top-down) regulatory processes of population and community dynamics (Collar et al, 2017;Benke, 2018) and by several empirical studies that found a relationship between the reproductive period/recruitment with periods of greatest rainfall (Mantelatto and Barbosa, 2005;Nogueira et al, 2019b;Oliveira et al, 2019). The hypothesis proposes that: [1] different population structures occur between seasons (dry and rainy), i.e., immature and small individuals predominating in the dry season and a predominance of adult individuals and larger size classes in the rainy season; and [2] a significant relationship will occur between juvenile abundance and rainfall.…”

“…In general, the sex ratio was inclined towards females in the population. This trend occurs frequently within the genus Macrobrachium (Garcia-Davila et al, 2000;Montoya, 2003;Mantelatto and Barbosa, 2005;Mattos and Oshiro, 2009;Tamburus et al, 2012;Pescinelli et al, 2016;Nogueira et al, 2019b), mainly in species in which males reach larger sizes compared to females. Many factors can influence sex ratio within the population, such as aggressiveness, migration, reproductive strategies, differential selection of microhabitats, and longevity (Karplus et al, 1991;Bauer, 2004;Karplus and Barki, 2019).…”

Molecular characterization and expression profiling of transformer 2 and fruitless-like homologs in the black tiger shrimp, Penaeus monodon

“…and Penaeus spp. ( Bajaniya et al, 2014 ; Nogueira et al, 2019 ). Penaeus monodon also exhibits differential growth rate in which the female shows superior growth to male.…”