Survivorship and fecundity ofArgulus bengalensis(Crustacea; Branchiura) under laboratory conditions

Abstract

The Life table features and the fecundity schedule of the fish louse Argulus bengalensis (Branchiura: Argulidae) were estimated under laboratory conditions using Cirrhinus mrigala as the model host. The cohort-based Life table revealed that survival of A. bengalensis declines as a function of age. Life expectancy was observed to be 34 days for a newly emerged adult. The mean number of eggs produced per egg strip was 86 (±8.89 S.E.). The sex ratio 2:1 was biased towards males. The net reproductive rate (R 0 ) varied between 50 and 487 while the cohort generation time (T c ) ranged between 24 and 26 days. The intrinsic rate of increase (r) was 0.14-0.23, while the finite rate of increase (λ) remained between 1.16 and 1.28. The Life table features and the fecundity schedule of A. bengalensis are comparable with congenerics of temperate regions. Early reproduction (between 21 and 23 days) and an extended postreproductive phase (47 days) of females are characteristic of A. bengalensis and a reflection for survival under uncertain conditions and a parasitic mode of life.

Histological and ultrastructural investigation of the female reproductive system of Argulus bengalensisRamakrishna, 1951 (Crustacea: Branchiura)

“…The branchiuran parasites belonging to the genus Argulus often increase their population size resulting in mass fish mortality (Menezes et al, ; Singhal et al, ; Grignard et al, ; Buchmann and Bresciani, ; Northcott et al, ; Pekmezci et al, ; Saha et al, ). The major determinant of their parasitic fitness is their high reproductive investment (Guha et al, , b) and the female reproductive system is fundamental to their reproductive efficiency. Some aspects of their reproductive biology, like the structural and functional organization of the female reproductive system remain unclear.…”

“…Many researchers, even prior, had conducted studies on the reproduction and population dynamics of Argulus spp. (Shafir and Oldewage, ; Mikheev et al, ; Harrison et al, ; Taylor et al, ; Guha et al, ). Especially at the time when the presence of spermatophores was still unknown in the genus, much information was published on the structural organization of the male reproductive system (Jurine, ; Leydig, ; Claus, ; Grobben, , Martin, ; Debaisieux, ; Wingstrand, ; Avenant‐Oldewage and Swanepoel, ).…”

Male reproductive system of the fish ectoparasiteArgulus bengalensis(Crustacea: Branchiura)

“…Exile into a separate enclave helps the spermatogonial cells to maintain their stem cell property by concealing themselves from the signals leading into differential pathway (Banerjee et al, ). This feature ultimately confers an advantage to their parasitic adaptability in terms of their endured fecundity throughout their reproductive phase (Guha et al, ) of life and hence, in the maintenance of their population size. The outer enclaves of the testicular lobes are connected to each other by an isthmus which means that substance can pass through it and creates an equivalent environment in the outer enclaves for maintenance of the spermatogonia.…”

Mutualistic association of rotifer Philodina roseola with the branchiuran fish ectoparasite Argulus bengalensis at its embryonic stage

“…On the other hand, Argulus being an ectoparasite results in the mass mortality in pisciculture. The life cycle of Argulus includes egg, larval, juvenile and adult stages [4]. The main survival strategy among their populations involves the maximization of reproduction to attain optimum fitness.…”

“…The life cycle of Argulus includes egg, larval, juvenile and adult stages [4]. The main survival strategy among their populations involves the maximization of reproduction to attain optimum fitness.…”