The parthenogenetic Marmorkrebs (Malacostraca: Decapoda: Cambaridae) is a triploid organism

Abstract

There is a close association between parthenogenesis and polyploidy. For this reason, we undertook a karyological analysis to test whether the parthenogenetic Marmorkrebs, Procambarus fallax forma virginalis, possesses an enlarged set of chromosomes. For this purpose, we karyotyped the Marmorkrebs, the sexual form of P. fallax (together called P. fallax complex), and the closely related species P. alleni. The latter shows 94 chromosomes in the haploid condition. In contrast to this, we found a haploid set of 92 chromosomes in individuals of the P. fallax complex. However, in mitotic metaphases the sexual form shows 184 chromosomes, whereas the Marmorkrebs possesses 276 chromosomes. Hence, the parthenogenetic Marmorkrebs reveals a triple amount of the haploid chromosome number. In addition, we detected a strikingly large subtelocentric chromosome which appears once in haploid and twice in diploid cells of sexual individuals of the P. fallax complex. In the parthenogenetic Marmorkrebs, this prominent chromosome occurs thrice. All this clearly reveals that the Marmorkrebs is a triploid organism. The applicability of the used methods, the significance of polyploidy in evolution of Decapoda, putative pathways to parthenogenetic triploidy, a possible hybrid origin and the scientific and ecological consequences of an increased chromosome set in Marmorkrebs are discussed.

Impact of Low-Molecule Acidic Peptides on Growth and Histological Structure of Inner Organs of Marbled Crayfish <i>Procambarus fallax</i> (Hagen, 1870)<i> F. virginalis</i>

“…In control, the cross sectional area segments of hepatopancreas reached 31332.11±1189.72 µm 2 , while the slices in the experiment were more than 42.3 % -4475.77±42147.38 µm 2 . The value of the tubule rift did not differ significantly -in the control area of the rift of the tubular reached 6301.07±409.37 µm 2 , in the experiment -6868.51±652.33 µm 2 . This means that the increase in the size of the lobules of hepatopancreas occurred due to tissue proliferation and accumulation of fat inclusions in these tissues.…”

“…In the control, area of the cross-section slices of lobules of hepatopancreas reached 31332.11±1189.72 µm 2 , while in the experiment segments were 42.3 % (p <0.05) bigger -42147.38±4475.77 µm 2 (Fig. 3).…”

“…Size of cells in the control were 948.09±69.22 µm 2 , in the experience -1403.76±80.37 µm 2 (Fig. 4).…”

“…As an invasive species marbled crayfish hit the waters of the Netherlands, Italy, Slovakia, Sweden, Croatia and Ukraine [7][8][9][10][11][12][13][14]. The main feature of the marbled crayfish is that its population consists entirely of triploid females and reproduction occurs by parthenogenesis [15]. All the offspring is genetically uniform.…”

Different aspects of reproduction strategies in crayfish: A review

“…The observed increase in a number of acuminate and pappose setae of putative mechanoreceptive function (Hobbs, 1972; around the gonopores and the annulus during maturation had not been described before in decapods (Vogt et al, 2004). Martin et al (2015) recently showed that the marbled crayfish is a triploid, showing a triple amount of the haploid number of chromosomes. In addition, they detected a huge amount of a subtelocentric chromosome which became clear firstly in haploid and secondly in diploid cells of sexual individuals of the P. fallax complex.…”