Gonadal structure analysis ofMacrobrachium amazonicum(Heller, 1862) from a wild population: a new insight into the morphotype characterization

Abstract

The aim of this work is to correlate the histological gonad analysis of adult male Macrobrachium amazonicum of a wild population with morphotypes identified in populations reared in earthen ponds. A total of 500 adult male specimens were collected in the Mosqueiro Island, Municipality of Belém, State of Pará, Brazil. The animals were classified on the basis of body and cheliped colour, second right cheliped spination, total length, cheliped length and weight. The gonads of each morphotype were fixed, processed by histological techniques and stained with haematoxylin and eosin. All four morphotypes, translucent claw (TC), cinnamon claw (CC), green claw 1 (GC1) and green claw 2 (GC2), were identified in the wild population, indicating the same population structure described for cultured animals. The M. amazonicum testes are composed of multiple lobes. The TC gonads showed a population of germ cells in the eccentric portion of the seminiferous tubule and few spermatozoa in the central region. Cinnamon claw males exhibited a large cell population with intense meiotic activity and sparse spermatozoa. Regardless of the different external morphologies of GC1 and GC2, no histological differences were found in their gonads; both had a large number of gametes and similar spermatogenic cell population. Despite the external morphological evidences of the four morphotypes, the histological criteria indicate the existence of only three morphotypes: TC, CC and green claw (GC).

Population biology of Macrobrachium jelskii (Miers, 1877) (Decapoda, Palaemonidae) from an artificial pond in Bahia, Brazil

“…This pattern has often been attributed to the occurrence of hermaphroditism in caridean shrimps (Wenner, 1972;Bauer, 2000;2004;Correa and Thiel, 2003). However, several studies focusing on histology and gonadal development found no evidence of hermaphroditism in species of Macrobrachium (Carvalho and Pereira, 1981;Damrongphol et al, 1991;Chaves and Magalhães, 1993;Mossolin and Bueno, 2002;Silva et al, 2009;Revathi et al, 2012). By ruling out hermaphroditism, variations in the sex ratio of populations of Macrobrachium spp.…”

Ocurrence of male morphotypes of Macrobrachium amazonicum (Caridea, Palaemonidae) in a population with an entirely freshwater life cycle

“…Papa et al (2004) and Silva et al (2009) studied the morphology of the testes of the male morphotypes of M. amazonicum, identified by Moraes-Riodades and Valenti (2004), demonstrating that GC1 and GC2 are very similar and thus, suggesting that they should be grouped together. Similarly, these two morphotypes presented similar body sizes in the present study, what was also demonstrated by Moraes-Riodades and Valenti (2004).…”

“…in the Eastern Amazon region (Silva et al, 2009; and in Northeastern Brazil (Santos et al, 2006). In a previous study, Pantaleão et al (2012) investigating the occurrence of different morphotypes in a continental population from a hydroelectric reservoir in the Tietê River, collected 587 males, in a period of one year, and only found TC morphotype (the first ontogenetic stage).…”

Effect of density on population development in the Amazon River prawn Macrobrachium amazonicum

“…Natural populations inhabiting coastal areas show great variability in size, due to heterogeneous growth caused by the existence of 4 male morphotypes (Moraes- Riodades & Valenti 2004, Santos et al 2006, da Silva et al 2009). Some population studies have been performed in the eastern (KCA Silva et al 2002a,b, 2005, MCN Silva et al 2007) and central (Odinetz-Collart 1991a,b) Amazon basin.…”