Morphometric correlates of host specificity in Dactylogyrus species (Monogenea) parasites of European Cyprinid fish

Parasitology ◽  
2001 ◽  
Vol 123 (2) ◽  
pp. 169-177 ◽  
Author(s):  
A. SIMKOVÁ ◽  
Y. DESDEVISES ◽  
M. GELNAR ◽  
S. MORAND

We test the hypothesis that living on larger fish may impose constraints, i.e. the need to develop large attachment organs, related to the necessity to remain attached on large gills. For this, we compiled data on body size and morphometric measurements of attachment organs of 44 Dactylogyrus species (ectoparasites with direct life-cycle) from 19 cyprinid species. Nineteen dactylogyrid species were considered as specialists (infecting only 1 host species) and 25 as generalists (infecting more than 1 species). The lack of phylogenetic information lead us to perform comparative analyses using raw values and independent contrasts obtained by random phylogenies. Our results show that rich parasite communities are formed by specialists and generalists whereas poor communities are composed mainly of generalist parasites. Moreover, specialists are found on larger hosts, which may reflect a specialization on a predictable resource, as larger fish live longer and offer large gills for parasite colonization. Parasite specialization is shown to be linked with adaptation of attachment organs to their fish hosts. Two morphometric variables of the attachment organ, the total length of anchor and length of base of anchor, were positively correlated with host length for specialists.

2012 ◽  
Vol 50 (No. 12) ◽  
pp. 537-542
Author(s):  
Ergonul MB ◽  
A. Altindag

Although Ligula intestinalis (L., 1758) has been recorded in several fish hosts, available data on the parasitization parameters of Ligula intestinalis plerocercoids such as prevalence, mean intensity and parasitic index in tench (Tinca tinca L., 1758) is limited. In this study, totally 272 fishes were investigated for the presence of L. intestinalis plerocercoids. The prevalence value was 40.01% of the whole fish sample and the mean intensity was 2.48. The lower IP values and mean intensity levels may provide some evidence of the strategy of Ligula in order to complete its life cycle. None of the parasitization parameters showed significant differences between the sexes.


1998 ◽  
Vol 38 (7) ◽  
pp. 73-79 ◽  
Author(s):  
Hooi-Ling Lee ◽  
Donald DeAngelis ◽  
Hock-Lye Koh

This paper discusses the spatial distribution patterns of the various species of the Unionid mussels as functions of their respective life-cycle characteristics. Computer simulations identify two life-cycle characteristics as major factors governing the abundance of a species, namely the movement range of their fish hosts and the success rate of the parasitic larval glochidia in finding fish hosts. Core mussels species have fish hosts with large movement range to disperse the parasitic larval glochidia to achieve high levels of abundance. Species associated with fish host of limited movement range require high success rate of finding fish host to achieve at least an intermediate level of abundance. Species with low success rate of finding fish hosts coupled with fish hosts having limited movement range exhibit satellite species characteristics, namely rare in numbers and sparse in distributions.


Parasitology ◽  
2011 ◽  
Vol 138 (9) ◽  
pp. 1183-1192 ◽  
Author(s):  
KRISTIN K. HERRMANN ◽  
ROBERT POULIN

SUMMARYEach transmission event in complex, multi-host life cycles create obstacles selecting for adaptations by trematodes. One such adaptation is life cycle abbreviation through progenesis, in which the trematode precociously matures and reproduces within the second intermediate host. Progenesis eliminates the need for the definitive host and increases the chance of life cycle completion. However, progenetic individuals face egg-dispersal challenges associated with reproducing within metacercarial cysts in the tissues or body cavity of the second intermediate host. Most progenetic species await host death for their eggs to be released into the environment. The present study investigated temporal variation of progenesis in Stegodexamene anguillae in one of its second intermediate fish hosts and the effect of the fish's reproductive cycle on progenesis. The study involved monthly sampling over 13 months at one locality. A greater proportion of individuals became progenetic in the gonads of female fish hosts. Additionally, progenesis of worms in the gonads was correlated with seasonal daylight and temperature changes, major factors controlling fish reproduction. Host spawning events are likely to be an avenue of egg dispersal for this progenetic species, with the adoption of progenesis being conditional on whether or not the parasite can benefit from fish spawning.


2010 ◽  
Vol 2 (4) ◽  
pp. 24-26
Author(s):  
Mustafa KOYUN ◽  
Faik Naci ALTUNEL

Dactylogyrus species are a group of monogenean gill parasites that are highly specific to freshwater fishes; represents the most dominant genus among the Monogenea with regard to host distribution and location. They were sampled 14 species from more than 27 host collected in Turkey. Among these dactylogyrid parasites, Dactylogyrus fraternus could be described and illustrated from specimens collected from gills of a cyprinid fish, bleak Alburnus alburnus, in Enne Dam reservoir from Kutahya, Turkey. Diagnostic characters of this species are the tegument of trunk showing annulations, except on the cephalic region, and copulatory complex comprising sclerotized, basal part broad, the tube which is long and hard. The purpose of the present study was to determine, on the whole, the body structure of the Dactylogyrus fraternus in bleak.


Parasitology ◽  
2002 ◽  
Vol 124 (6) ◽  
pp. 625-629 ◽  
Author(s):  
A. LEVSEN ◽  
P. J. JAKOBSEN

This paper describes the ability of the Asian fish nematode Camallanuscotti to carry out both heteroxeny, i.e. an indirect life-cycle using copepods as intermediate host, and monoxeny, i.e. direct infection and development in the definitive fish host. C. cotti occurs naturally in various freshwater teleosts in Asia. During the past decades it has been disseminated into closed or semi-closed aquaculture systems and aquaria around the world, mainly due to the ornamental fish trade. Under such conditions the species may frequently face a bottleneck situation with regard to the availability of copepods. It is known that C. cotti may reproduce and persist in copepod-free aquaria for several months. In order to investigate whether C. cotti has selected towards monoxeny in water systems lacking copepods, in contrast to the opposite selection pressure when copepods are present, 2 separate infection trials were run. It was shown that the parasite can infect the fish host both indirectly via copepods, and directly. However, C. cotti has significantly higher fitness, expressed as survival to maturity, when transmitted indirectly compared to the direct transmission mode. We suggest that the ability of aquarium populations of C. cotti to carry out a direct life-cycle is favoured by selection in order to avoid extinction whenever copepods are absent. It still remains unknown, however, whether the parasite shows the same characteristics in the wild.


Parasitology ◽  
1975 ◽  
Vol 71 (3) ◽  
pp. 493-503 ◽  
Author(s):  
A. A. Banaja ◽  
J. L. James ◽  
J. Riley

A direct life-cycle inReighardia sternae, a cephalobaenid pentastomid of gulls was investigated: the work was prompted by a report of eggs and larvae recovered from the stomach and intestine of a naturally infected gull.Infective pentastomid eggs were obtained by surgically transplanting maturing femaleReighardia, taken from freshly shot wild gulls, into captive recipients. Faecal material from birds thus artificially infected was collected daily and examined for eggs. Eggs were force fed to 33 hand-reared (from eggs or nestlings) juvenile gulls which were selected at random and sacrificed at intervals thereafter and examined for pentastomids.One hour after infection, primary larvae appear in the body cavity where they moult immediately. They grow steadily and by 27–35 days are sexually differentiated, and by 66 days have copulated. Fertilized females take a further 116 days to produce eggs by which time they are 7·6 cm long.The complex migrations undertaken by developing larvae in the gull, and the problems of the mechanism of direct transmission, are discussed.


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