Seasonal population dynamics and maturation of Neoechinorhynchus pungitius (Acanthocephala: Neoechinorhynchidae) infecting brook stickleback, Culaea inconstans, from Sioux Creek, Wisconsin, U.S.A.

1989 ◽  
Vol 67 (3) ◽  
pp. 590-595 ◽  
Author(s):  
Becky A. Lasee
Keyword(s):  
Population Dynamics ◽  
Egg Production ◽  
Seasonal Periodicity ◽  
Culaea Inconstans ◽  
Mean Intensity ◽  
Host Sex ◽  
Significant Difference ◽  
Brook Stickleback ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

Seasonal population dynamics and maturation of the acanthocephalan Neoechinorhynchus pungitius from brook stickleback (Culaea inconstans) were investigated. Stickleback were collected monthly at Sioux Creek, Wisconsin from April 1981 to May 1982 (excluding December, January, and February). Forty-seven percent (292/620) were infected with N. pungitius, which exhibited seasonal periodicity in prevalence, mean intensity, and maturation. Prevalence and mean intensities were lowest in summer and increased through autumn owing to recruitment of juvenile and immature worms. Prevalence and mean intensity reached their peaks by April and May, and N. pungitius infrapopulations were composed primarily of mature worms. Egg production began in May and continued throughout early summer. Neoechinorhynchus pungitius males appeared shorter lived than females, as the June and July infrapopulations were comprised mostly of females. Prevalence and mean intensity of N. pungitius increased as brook stickleback length increased. There was no significant difference between numbers of male and female fish infected or between mean intensity and host sex.

Seasonal population dynamics of Neoechinorhynchus qinghaiensis in the carp, Gymnocypris przewalskii przewalskii, from Qinghai Lake, China

2001 ◽  
Vol 75 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Yang Tingbao ◽  
Liao Xianghua
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Feeding Habits ◽  
Host Population ◽  
Qinghai Lake ◽  
Mean Intensity ◽  
Gymnocypris Przewalskii ◽  
The Mean ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

Studies on the seasonal population dynamics ofNeoechinorhynchus qinghaiensis(Acanthocephala: Neoechinorhynchidae) in its fish hostGymnocypris przewalskii przewalskiiin the Qinghai Lake, China, were carried out with samples taken in May 1991, August 1992, November 1992 and February 1993. Prevalences were higher than 44% in all seasons. The mean intensity of infection was above 124 worms per fish. The maximum intensity of worms recovered from a single fish was 1402 in the autumn of 1992. Differences in the mean abundance, mean intensity and prevalence are not statistically significant relative to season and this is likely to be related to the stable temperatures recorded at the bottom of Qinghai Lake. Over-dispersed distributions ofN. qinghaiensisin the host population, due to heterogeneity and feeding habits, were observed in all seasons. The size composition of both sexes ofN. qinghaiensisshowed males to be less than 3.5 mm and females between 0.5 and 4.25 mm, with the main recruitment phase in the worm populations occurring in the autumn, extending through winter and spring with the lowest recruitment occurring in the summer. The maturation and copulation of worms were mainly focused in the summer season. The sex ratio of female to male was both high in winter (1.51:1) and spring (1.48:1). The higher proportion of females and the change in the worm sex ratio in winter can be attributed to the reduced longevity of male worms. As immature male worms exhibit a higher proportion of the worm population than females in all seasons, further studies are needed to determine if such a situation compensates for the shorter life span of males.

scholarly journals Seasonal population dynamics of the monogeneans Quadriacanthus kobinensis parasitising Clarias fuscus in Pearl River, China

2016 ◽  
Vol 53 (1) ◽  
pp. 105-108
Author(s):  
J. J. Hu ◽  
H. Y. Li
Keyword(s):  
Population Dynamics ◽  
Body Length ◽  
Infection Intensity ◽  
Field Investigation ◽  
Pearl River ◽  
Mean Intensity ◽  
Maximum Abundance ◽  
Clarias Fuscus ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

SummaryThis paper describes the population dynamics of Quadriacanthus kobinensis on the gills of Clarias fuscus following a field investigation from June 2012 to May 2013 in Pearl River, China. The results showed that in Q. kobinensis prevalence was highest (70.13 %) in the summer and Mean intensity reached a peak in the autumn. The maximum number of Q. kobinensis in a fish was 474. The maximum abundance occurred during summer (25.8) and the minimum values during spring. Q. Kobinensis exhibited an aggregated distribution in all seasons. The highest prevalence was in hosts of 28 cm<L and the infection intensity was also the highest in this group. In terms of infection intensity, host of 28 cm<L differed significantly from those of 24<L≤26 cm, but no significant differences existed in other body length groups.

The population dynamics of metacercariae of Apatemon gracilis (Trematoda: Digenea) in three species of lake-dwelling leeches

Parasitology ◽  
1986 ◽  
Vol 93 (3) ◽  
pp. 517-530 ◽  
Author(s):  
S. M. Spelling ◽  
J. O. Young
Keyword(s):  
Population Dynamics ◽  
Relative Density ◽  
Sexual Maturity ◽  
Egg Production ◽  
Seasonal Pattern ◽  
Distinct Pattern ◽  
The Other ◽  
Mean Intensity ◽  
Density Values ◽  
Host Mortality

SUMMARYMonthly samples of the leeches Erpobdella octoculata, Glossiphonia complanata and Helobdella stagnalis were taken over a two-year period from an eutrophic, English lake to detect metacercariae of the trematode, Apatemon gracilis. In each cohort of each of the three leeches, prevalence was low in young individuals, rose to a peak in autumn/winter, and then declined until the cohort had almost died out; in E. octoculata and H. stagnalis a final brief increase occurred. Mean intensity and relative density values followed a similar seasonal pattern of change to that of prevalence in these last two species, but in G. complanata values fluctuated irregularly with no distinct pattern. The frequency distribution of the parasite in G. complanata was highly over-dispersed, but less so in the other two species. Infected E. octoculata reached sexual maturity. The parasite reduced egg production in G. complanata and H. stagnalis, but only by maximum values of 2·5 and 9% respectively. This reduction in fecundity is low compared to the subsequent high mortality, at 95% or more, of newly recruited young from as yet unidentified causes. Parasite-related host mortality was difficult to assess in young leeches, but there was some evidence for its occurrence in older leeches of E. octoculata and H. stagnalis. However, this is unlikely to play a prominent role in the control and regulation of lacustrine leech populations.

scholarly journals Seasonal population dynamics of the clover cyst nematode (Heterodera trifolii)

2000 ◽  
Vol 53 ◽  
pp. 452-452
Author(s):  
P.P. Kyi ◽  
P.G. Long ◽  
C.F. Mercer ◽  
R.A. Skipp ◽  
G.W. Yeates
Keyword(s):  
Population Dynamics ◽  
Cyst Nematode ◽  
Seasonal Population ◽  
Seasonal Population Dynamics

Seasonal population dynamics of a specialized termite-eating spider (Araneae: Ammoxenidae) and its prey (Isoptera: Hodotermitidae)

Pedobiologia ◽  
2016 ◽  
Vol 59 (3) ◽  
pp. 105-110 ◽  
Author(s):  
Charles Richard Haddad ◽  
Marek Brabec ◽  
Stano Pekár ◽  
René Fourie
Keyword(s):  
Population Dynamics ◽  
Seasonal Population ◽  
Seasonal Population Dynamics
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