Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae)
Проанализировано соотношение особей, находящихся на разных стадиях онтогенеза в части популяции Gyrodactylus sphinx Dmitrieva et Gerasev, 2000, мигрирующей на нового хозяина. Среди иммигрировавших гиродактилид доля особей с функционирующей мужской половой системой, способных размножаться только поло...
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irk-123456789-37182009-09-01T17:25:48Z Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) Dmitrieva, E.V. Краткие сообщения Проанализировано соотношение особей, находящихся на разных стадиях онтогенеза в части популяции Gyrodactylus sphinx Dmitrieva et Gerasev, 2000, мигрирующей на нового хозяина. Среди иммигрировавших гиродактилид доля особей с функционирующей мужской половой системой, способных размножаться только половым путем, составляет 72%. Таким образом, трансмиссия Gyrodactylus sphinx осуществляется главным образом за счет особей с функционирующей мужской половой системой. Половое созревание, по-видимому, и является пусковым механизмом миграционного поведения гиродактилид. Узкая встречаемость G. sphinx в природе соответствует его врожденной строгой специфичности. По-видимому, особи G. sphinx находят подходящего хозяина, ориентируясь по его физиологическим параметрам и благодаря их собственным поведенческим особенностям. The ratio between the different ontogenetic stages of gyrodactylids transferred from infected to uninfected hosts was studied. 72% of transmitted individuals have a functional male reproductive system and can reproduce only sexually. Therefore, in Gyrodactylus sphinx Dmitrieva et Gerasev, 2000 transmission mainly involves individuals with a functional male reproductive system. It is likely that the sexual maturation of gyrodactylids provides the trigger for migratory behaviour. The restricted occurrence of G. sphinx on one host species in nature is a result of innate host specificity. Both the behavioural patterns of G. sphinx and physiological parameters of the fish uphold the search for a suitable host. 2003 Article Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) / E. V. Dmitrieva // Вестн. зоологии. — 2003. — Т. 37, № 2. — С. 67-72. — англ. 0084-5604 http://dspace.nbuv.gov.ua/handle/123456789/3718 595.12 en Інститут зоології ім. І. І. Шмальгаузена НАН України |
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Краткие сообщения Краткие сообщения Dmitrieva, E.V. Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) |
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Проанализировано соотношение особей, находящихся на разных стадиях онтогенеза в части популяции Gyrodactylus sphinx Dmitrieva et Gerasev, 2000, мигрирующей на нового хозяина. Среди иммигрировавших гиродактилид доля особей с функционирующей мужской половой системой, способных размножаться только половым путем, составляет 72%. Таким образом, трансмиссия Gyrodactylus sphinx осуществляется главным образом за счет особей с функционирующей мужской половой системой. Половое созревание, по-видимому, и является пусковым механизмом миграционного поведения гиродактилид. Узкая встречаемость G. sphinx в природе соответствует его врожденной строгой специфичности. По-видимому, особи G. sphinx находят подходящего хозяина, ориентируясь по его физиологическим параметрам и благодаря их собственным поведенческим особенностям. |
| format |
Article |
| author |
Dmitrieva, E.V. |
| author_facet |
Dmitrieva, E.V. |
| author_sort |
Dmitrieva, E.V. |
| title |
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) |
| title_short |
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) |
| title_full |
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) |
| title_fullStr |
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) |
| title_full_unstemmed |
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) |
| title_sort |
transmission triggers and pathways in gyrodactylus sphinx (monogenea, gyrodactylidae) |
| publisher |
Інститут зоології ім. І. І. Шмальгаузена НАН України |
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2003 |
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Краткие сообщения |
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http://dspace.nbuv.gov.ua/handle/123456789/3718 |
| citation_txt |
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) / E. V. Dmitrieva // Вестн. зоологии. — 2003. — Т. 37, № 2. — С. 67-72. — англ. |
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AT dmitrievaev transmissiontriggersandpathwaysingyrodactylussphinxmonogeneagyrodactylidae |
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2025-07-02T06:58:43Z |
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2025-07-02T06:58:43Z |
| _version_ |
1836517450032611328 |
| fulltext |
UDC 595.12
TRANSMISSION TRIGGERS
AND PATHWAYS IN GYRODACTYLUS SPHINX
(MONOGENEA, GYRODACTYLIDAE)
E. V. Dmitrieva
Institute of Biology of the Southern Seas, Nakhimov av., 2, Sevastopol, 99011 Ukraine
Accepted 10 April 2001
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae). Dmitrie-
va E. V. — The ratio between the different ontogenetic stages of gyrodactylids transferred from infected
to uninfected hosts was studied. 72% of transmitted individuals have a functional male reproductive
system and can reproduce only sexually. Therefore, in Gyrodactylus sphinx Dmitrieva et Gerasev, 2000
transmission mainly involves individuals with a functional male reproductive system. It is likely that the
sexual maturation of gyrodactylids provides the trigger for migratory behaviour. The restricted
occurrence of G. sphinx on one host species in nature is a result of innate host specificity. Both the
behavioural patterns of G. sphinx and physiological parameters of the fish uphold the search for a
suitable host.
K e y wo r d s: Gyrodactylidae, Gyrodactylus, transmission, trigger, host specificity.
Ïóñêîâîé ìåõàíèçì ðàññåëåíèÿ è íàïðàâëåíèå òðàíñìèññèè Gyrodactylus sphinx (Monogenea, Gyro-
dactylidae). Äìèòðèåâà Å. Â. — Ïðîàíàëèçèðîâàíî ñîîòíîøåíèå îñîáåé, íàõîäÿùèõñÿ íà ðàçíûõ
ñòàäèÿõ îíòîãåíåçà â ÷àñòè ïîïóëÿöèè Gyrodactylus sphinx Dmitrieva et Gerasev, 2000,
ìèãðèðóþùåé íà íîâîãî õîçÿèíà. Ñðåäè èììèãðèðîâàâøèõ ãèðîäàêòèëèä äîëÿ îñîáåé ñ
ôóíêöèîíèðóþùåé ìóæñêîé ïîëîâîé ñèñòåìîé, ñïîñîáíûõ ðàçìíîæàòüñÿ òîëüêî ïîëîâûì
ïóòåì, ñîñòàâëÿåò 72%. Òàêèì îáðàçîì, òðàíñìèññèÿ Gyrodactylus sphinx îñóùåñòâëÿåòñÿ ãëàâíûì
îáðàçîì çà ñ÷åò îñîáåé ñ ôóíêöèîíèðóþùåé ìóæñêîé ïîëîâîé ñèñòåìîé. Ïîëîâîå ñîçðåâàíèå,
ïî-âèäèìîìó, è ÿâëÿåòñÿ ïóñêîâûì ìåõàíèçìîì ìèãðàöèîííîãî ïîâåäåíèÿ ãèðîäàêòèëèä.
Óçêàÿ âñòðå÷àåìîñòü G. sphinx â ïðèðîäå ñîîòâåòñòâóåò åãî âðîæäåííîé ñòðîãîé ñïåöèôè÷íîñòè.
Ïî-âèäèìîìó, îñîáè G. sphinx íàõîäÿò ïîäõîäÿùåãî õîçÿèíà, îðèåíòèðóÿñü ïî åãî
ôèçèîëîãè÷åñêèì ïàðàìåòðàì è áëàãîäàðÿ èõ ñîáñòâåííûì ïîâåäåí÷åñêèì îñîáåííîñòÿì.
Êëþ÷åâûå ñ ëîâ à: Gyrodactylidae, Gyrodactylus, òðàíñìèññèÿ, ïóñêîâûå ìåõàíèçìû, ñïåöèôè÷íîñòü.
Introduction
Although numerous studies of the biology and ecology of Gyrodactylus Dmitrieva et Gerasev, 2000
(Monogenea, Gyrodactylidae) have been conducted, the behavioural triggers involved in the transmission of
gyrodactylids and, especially, in the abandonment of a suitable host are as yet unknown. The hypothesis that
transmission begins with the accidental detachment of gyrodactylids or an accidental contact of hosts seems
dubious, inasmuch as transmission is too important to occur by chance. Known host-parasite systems exhibit
a great diversity of specific mechanisms which efficiently enable dispersion of the parasites. Therefore, it
seems rather questionable to assume that gyrodactylids have not developed similar mechanisms. Looking at
data on the biology of Gyrodactylus, it appears reasonable to suppose that the development of the male
reproductive system may be the trigger for their migratiory behaviour. In oviparous monogeneans cross-
transmission induced by sexual maturation is common. For example, sexually mature gill-parasitic
monogeneans, such as Ancyrocephalus paradoxus and some species of both Dactylogyrus and Diplectanum,
move along the gill forming aggregations of individuals prior to fertilization (see inter alia Oliver, 1976;
Izumova, Zharikova, 1982; Gerasev, Starovoitov, 1988; Dorovskikh, Matrokhina, 1991). Entobdella solea, the
early stages of development of which take place on the upper surface of the its host, migrate to the lower
surface of the fish on reaching sexual maturity (Kearn, 1963).
In order to validitate this hypothesis, the composition the ontogenetic stages in the population of
gyrodactylids migrating from infected hosts to uninfected ones was analysed.
Material and methods
Gyrodactylus sphinx Dmitrieva et Gerasev, 2000 parasitizes the Black Sea blenny, Blennius sphinx Va-
lenciennes. Four ontogenetic stages of the worm (fig. 1) were distinguished based on the development of the
Vestnik zoologii, 37(2): 67–72, 2003
© E. V. Dmitrieva, 2003
Fig. 1. Ontogenetic stages of gyrodactylids according to the development of reproductive system and embryo:
1 — new born (1a) pre-first birth individuals (1b); 2 — immediately post-first birth individuals; 3 — pre-
second or pre-third birth individuals; 4 — post-second or post-third birth individuals.
Ðèñ. 1. Còàäèè îíòîãåíåçà ãèðîäàêòèëèä, îïðåäåëÿåìûå ïî ñòåïåíè ðàçâèòèÿ ðåïðîäóêòèâíîé ñèñòå-
ìû è ýìáðèîíà: 1 — íîâîðîæäåííàÿ (1à) ïåðåä îòðîæäåíèåì ïåðâîãî ïîòîìêà (1b) îñîáè; 2 — îñîáü
ñðàçó æå ïîñëå îòðîæäåíèÿ ïåðâîãî ïîòîìêà; 3 — îñîáü ïåðåä îòðîæäåíèåì âòîðîãî èëè òðåòüåãî ïî-
òîìêà; 4 — îñîáü ïîñëå îòðîæäåíèÿ âòîðîãî èëè òðåòüåãî ïîòîìêà.
male reproductive system and embryo using data presented by Harris (1985): 1 — the new-born (1a)/pre-
first birth (1b) individuals, which have an advanced embryo, have no penis and can reproduce only asexually;
2 — the immediately post-first birth individuals, which have an embryo consisting of several cells and no
penis. At this stage the male reproductive system is still under development, thus the second embryo is formed
without fertilization, although the following one will definitely be the result of fertilization; 3 — the pre-
second and pre-third birth individuals, which have a penis and an advanced embryo. The latter could result
from both asexual (if it is the second embryo) and sexual (if the third embryo) reproduction, but subsequently
they will reproduce only sexually; 4 — the post-second or post-third birth individuals, which have a functional
male reproductive system and a uterus either empty or containing a very small embryo. These individuals also
reproduce only sexually.
Two specimens of the host (B. sphinx) infected with G. sphinx and one uninfected were placed in an
aquarium filled with 1 litre of the seawater at a temperature of 16°C. Average initial intensity of infection was
8 worms per host. Seven replicates were performed, each lasting for 10 days. Transmitted gyrodactylids were
68 E. V. Dmitrieva
* The stages of gyrodactylid ontogenesis: 1s — the pre-first birth/new-born individuals; 2s — immediately
post-first birth individuals; 3s — the pre-second or pre-third birth individuals; 4s — the post-second or
post-third birth individuals.
Ta b l e 1. Ontogenetic stages of Gyrodactylus sphinx transmitted from infected fish to uninfected fish and the
transmission rate
Ò à á ëèö à 1. Ñòàäèè îíòîãåíåçà îñîáåé Gyrodactylus sphinx, èììèãðèðîâàâøèõ íà íåçàðàæåííîãî
õîçÿèíà è ñêîðîñòü òðàíñìèññèè
Day
Replicate
Initial
infection
of 2 fishes 1 2 3 4 5 6 7 8 9 10
Average
per day
1 7, 9 0 0 3s* 4s, 2s 2s, 3s 2s 3s 4s 0 0 0,8
2 10, 12 0 2s 3s, 3s 4s 2s, 4s 3s 4s 4s 4s 0 1
3 10, 8 0 3s 3s, 4s 2s, 4s 2s, 4s 2s 3s 4s 0 0 1
4 10, 7 0 0 2s 2s 4s 3s 4s 4s 0 0 0,6
5 9, 8 0 0 3s 3s, 2s 4s, 3s 4s 0 4s 0 0 0,7
6 10, 7 0 0 2s, 2s 3s, 4s 4s, 4s 3s 0 3s 0 0 0,8
7 7, 8 0 0 2s 3s 2s 0 3s 4s 0 0 0,5
Average: 8 Average: 0,8
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae)
immediately detached from the host and their developmental stages determined. The blennies were examined
daily. The resulting data are presented in table 1.
Other experiments were carried out in order to determine the host specificity of G. sphinx. In the first
experiment B. sphinx, the typical host of G. sphinx, were placed an aquarium with other fish species (Blennius
pavo Risso, B. sanguinolentus Pallas, Neogobius melanostomus (Pallas)) from the same natural habitat. Seven
replicates were performed: 1 — fishes were examined after 1 day of exposure to the parasite; 2 — after 2 days;
3 — after 3 days; and so on. In another experiment, several G. sphinx were placed on specimens of B. pavo
and B. sanguinolentus, which were then examined hourly. The longest exposure time in this experiment was
5 hours. The experiment was replicated 5 times.
Results and discussion
A sum total of 54 gyrodactylids transferred to a new host, with a mean rate of
transmission from infected to uninfected host of 0.8 per day. The first ontogenetic stage
was not found among the transmitted gyrodactylids. The proportion of immediately
post-first birth individuals with a second embryo and in which the male reproductive
system is under development (2nd stage) was 28%; the remainding 72% were those with
a functional male reproductive system and a sexual reproduction mode (third and
fourth stages) (tabl. 2).
Such a population structure of developmental stages among the transmitted gyro-
dactylids cannot be the result of the accidental detachment of worms, because acciden-
tal detachment is equally likely for all developmental stages. Furthermore, these exper-
imental results differ from those known for these stages in gyrodactylid populations. For
example, half the Gyrodactylus turnbulli Harris, 1986 population consists of the pre-first
birth worms, and the proportion of post-second and post-third birth worms is less than
2%; and populations of G. arcuatus Bychowsky, 1933 and G. gasterostei Glaser, 1974
include 55% pre-second birth individuals and only 5% of post-second and post-third
birth worms (Harris, 1985, 1988, 1993). Among the transmitted individuals of G. sphinx
there are no the pre-first birth worms, whereas the post-second and post-third birth
worms (4th stage) comprise almost 40%, i. e. 6 times as many as normally occurs in
the population. (fig. 2). Therefore, the migration of this stage cannot be accidental and
may well result from behavioural changes associated with sexual maturity.
Moreover, data on the distribution of these stages among gyrodactylids recovered
from sediment (Harris, 1988) agrees with our data from transmitted forms. High val-
ues of the portions of third and fourth stages found in sediment (fig. 3) have been
explained by Harris as exclusively the result of age-specific mortality. However, direct
evidence is not available, because all worms are found alive. Furthermore, both our data
and that of Scott and Anderson (1984) indicate that detached gyrodactylids can move
successfully to a new host. It is likely that mature gyrodactylids are more abundant in
sediment than on fish through active migration from their hosts.
The ratio between the ontogenetic stages of G. arcuatus on the gills and on the skin
(Harris, 1993) agrees with the model of gyrodactylid transmission presented here. The
percentage of “on-skin” gyrodactylids with a functional male reproductive system is
several times greater that on the gills (fig. 4). This disparity can hardly be explained by
Ta b l e 2. The percentage of the ontogenetic stages of Gyrodactylus sphinx in specimens transmitted to various
uninfected fish
Ò à á ëèö à 2. Ïðîöåíò îñîáåé ðàçíûõ îíòîãåíåòè÷åñêèõ ñòàäèé Gyrodactylus sphinx, èììèãðèðîâàâøèõ ñ
çàðàæåííûõ ðûá íà íåçàðàæåííûõ
Replicate
Stage
1 2 3 4 5 6 7
Total ± Sx, %
2s 37.5 20 30 33 14 25 40 28.5 ± 9.4
3s 37.5 30 30 17 43 37.5 40 33.6 ± 8.8
4s 25 50 40 50 43 37.5 20 37.9 ± 11.6
69
age mortality, and is more likely due to the displacement of sexually mature worms
from fish gills to the skin prior to transmission to a new host.
We suggest that the searching behaviour of gyrodactylids is induced by the physi-
ological changes which accompany the development of the male reproductive system.
The transmission of sexually mature organisms from host to host aids the survival
of the species. Asexual reproduction leads to the gyrodactylid stock on one host con-
sisting of several asexual clones of the same species. Cross-fertilization between these
closely related individuals increases the risk of the homozygosity of recessive characters.
Therefore, the immigration of mature parasites to other hosts helps maintain heterozy-
gosis in the population and increases genetic diversity, which also promotes the survival
of the species in general.
70 E. V. Dmitrieva
Fig. 3. Ratio between the ontogenetic stages (see fig. 1) of Gyrodactylus turnbulli on the skin of Poecilia
reticulata (A) and in sediment (B) (using data from Harris, 1988).
Ðèñ. 3. Ñîîòíîøåíèå îñîáåé Gyrodactylus turnbulli, íàõîäÿùèõñÿ íà ðàçíûõ ñòàäèÿõ îíòîãåíåçà
(ðèñ. 1), íà êîæå Poecilia reticulata (À) è â îñàäêå (Â) (èñïîëüçîâàííû äàííûå èç ðàáîòû Ï. Õàððè-
ñà, 1988).
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
p
ro
p
o
rt
io
n
o
f
to
ta
l
1 2 3 4
development stages
A
B
Fig. 2. Ratio between the ontogenetic stages (see fig. 1) in the entire population of Gyrodactylus sphinx (A)
and between individuals which have migrated to a new host (B).
Ðèñ. 2. Ñîîòíîøåíèå îñîáåé, íàõîäÿùèõñÿ íà ðàçíûõ ñòàäèÿõ îíòîãåíåçà (ñì. ðèñ. 1), âî âñåé ïîïó-
ëÿöèè Gyrodactylus sphinx (A) è ñðåäè îñîáåé, èììèãðèðîâàâøèõ íà íîâîãî õîçÿèíà (B).
0
0,1
0,2
0,3
0,4
0,5
p
ro
p
o
rt
io
n
o
f
to
ta
l
1 2 3 4
ontogenetical stages
A
B
Bakke et al. (1992) have described different transmission pathways for gyro-
dactylids and have pointed out that worms behaviour is an essential component of the
dispersal strategy of these worms. In order to clarity the specific mechanism of trans-
mission used by G. sphinx in the Black Sea coastal environment, a number of experi-
ments were carried out. In nature this species is found only on one host, Blennius
sphinx. Under experimental conditions, G. sphinx did not leave its natural host and
move to other fish species placed in the same aquarium. When these gyrodactylids were
mechanically transferred to atypical hosts, they detached within a few hours, which
clearly indicates a strictly physiological mechanism for maintaining the presence of
G. sphinx on its appropriate host. Therefore, this gyrodactylid species does not appar-
ently use a transport host as an aid to transmission in its natural environment. On the
other hand, this species has a behavioural mechanism which enables an efficient search
for a suitable host. All of the detached worms were found on the bottom and walls of
the aquarium and ignored all macrophytes. This behaviour is congruent with the behav-
iour of its host, the blenny, which prefers to locate on the substrate and away from
macrophytes.
Thus, Gyrodactylus sphinx transmission is undertaken by individuals with a func-
tional male reproductive system, and the trigger for their migratory behaviour may be
sexual maturation. The narrow occurrence of this monogenean in nature totally coin-
cides with its innate host specificity. In their search for a suitable host these worms are
abetted by physiological parameters of the host and by their own behavioural patterns.
The author is grateful to Dr. D. I. Gibson for checking the English of the paper.
Bakke T. A., Harris P. D., Jansen P. A., Hansen L. P. Host specificity and dispersal strategy in gyrodactylid
monogeneans, with particular reference to Gyrodactylus salaris (Platyhelminthes, monogenea) //
Diseases of Aquatic Organisms. — 1992. — 13. — P. 63–74.
Dorovskikh G. N., Matrokhina S. N. Distribution of some species of parasites on the gills of ruff //
Parazitologiya. — 1987. — 21. — P. 64–68. — Russian.
Gerasev P. I., Starovoitov V. K. Distribution of Ancyrocaphalus paradoxus (Monogenea) on gills of mature
specimens of Stizostedion lucioperca from Kurschskiji Bay // Proc. Zool. Inst. Ac. Sci. USSR. —
1988. — 177. — P. 89–99. — Russian.
Izumova N. A., Zharikova T. I. About some peculiarities of distribution of Dactylogirus anchoratus and
D. chranilowi (Monogenoidea (Beneden) Bychowsky, 1937; Dactylogiridea Bychowsky, 1937) on gills
Fig. 4. Ratio between ontogenetic stages (see fig. 1) of Gyrodactylus arcuatus on the gill (A) and on the skin
(B) of Gasterosteus aculeatus (using data from Harris, 1993).
Ðèñ. 4. Ñîîòíîøåíèå îñîáåé Gyrodactylus arcuatus, íàõîäÿùèõñÿ íà ðàçíûõ ñòàäèÿõ îíòîãåíåçà (ðèñ.1), íà æàáðàõ
(À) è êîæå (Â) Gasterosteus aculeatus (èñïîëüçîâàííû äàííûå èç ðàáîòû Ï. Õàððèñà, 1988).
0
0,05
0,1
0,15
0,2
0,25
0,3
0,35
0,4
0,45
0,5
p
ro
p
o
rt
io
n
o
f
to
ta
l
1 2 3 4
ontogenetical stages
A
B
Transmission Triggers and Pathways in Gyrodactylus sphinx (Monogenea, Gyrodactylidae) 71
of carps // Hydrobiol. character. of the Volga basin reservoirs. — Leningrad : Nauka, 1982. —
P. 89–100. — Russian.
Harris P. D. Observations on the development of the male reproductive system in Gyrodactylus gasterostei
Glaser, 1974 // Parasitology. — 1985. — 91. — P. 519–529.
Harris P. D. Changes in the site specificity of Gyrodactylus turnbulli Harris, 1986 (Monogenea) during
infections of individual guppies (Poecilia reticulata Peters) // Can. J. Zool. — 1988. — 66. —
P. 2854–2857.
Harris P. D. Interactions between reproduction and population biology in gyrodactylid monogeneans —
a review // Bull. Fr. Peche Piscic. — 1993. — 328. — P. 47–65.
Kearn G. C. The life cycle of the monogenean Entobdella solea, a skin parasite of the common sole //
Parasitology. — 1963. — 53. — P. 253–263.
Oliver G. New observations on biology and ecology of some Diplectanidae (Monogenea:
Monopistocotylea) // Proc. Inst. Biol. Pedology of Far-Eastern Sci. Centre of Ac. Sci. USSR. —
1976. — 34. — P. 104–109. — Russian.
Scott M. E., Anderson R. M. The population dynamics of Gyrodactylus bullatarudis within laboratory
populations of the fish host Poecilia reticulata // Parasitology. — 1984. — 89. — P. 217–236.
72 E. V. Dmitrieva
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