Sudies on the breeding behaviour of guppy fish, Poecilia reticulata(Peters), under laboratory conditions
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Date
2009
Authors
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Publisher
CCSHAU
Abstract
Guppy (Poecilia reticulata (Peters)) is an important ornamental aquarium fish.
Courtship behaviour of this fish has been of interest to ecologists and evolutionary biologists.
This is a cannibalistic fish which creates problems in keeping this fish in the aquaria.
The adult guppy fishes were procured from the local market. These fishes were put
in an aquarium of 24” ×12”×12” size, having filled with pond water. The fishes were fed on
natural food @ 800-1000 zooplankton per aquarium on alternate days and artificial food
(Toya Fish Food) @ 1g per aquarium twice a day was given. These feed levels kept the
hydrological factors at optimum range.
The aquarium was provided with water plants like Hydrilla and
Ceratophyllum to give shelter to the new born. The latter were segregated each day and
then transferred to other culture tanks as explained above to avoid predation by the adult
fishes. The length and weight of the growing male and female fishes fed on above
mentioned feed was monitored at different ages. The age specific size of the fishes was
then determined. Mature males and females in different ratios were taken in the
experimental aquarium and their behavioural displays towards each other were recorded in
large number of trials and comparisons were made. The observations on female and male
mate choices as influenced by the size, color and number of opposite sex and reproductive
stages were recorded. The time budget of males and females of different ages and
reproductive stages, and in different sex ratios were also recorded. The effect of previous
feeding levels on the future time budgets of males was also studied.
In breeding experiments, effect of different sex ratios (female: male) on the fecundity of
female guppy fish was recorded. Likewise, effect of four protection designs on the gestation
period and fecundity of female, and survival of young guppy fish were determined.
Guppy fish raised on the recommended food source showed proportionate body
growth with age. The anal fin in 8 weeks old males (2.5 cm) developed in to gonopodium
and in 12 weeks old males (3.0 cm) gonopodium hood was developed. At this age/size, the
males were considered to be capable of mating, although it was not certain whether sperms
were available or not in such males.
Males showed sigmoid displays and sneaky mating attempts where as females
showed approach and fleeing behavior. In 1: 1 female: male ratio, all the males showed
sigmoid displays only, and none showed sneaky mating attempts. However, when the males
of different ages/sizes competed for the mate, they showed both kinds of displays; the
frequency of sneaky display/ attempt was lower than the sigmoid display. It was further
indicated that males of 3.5 cm length were sexually mature to attract the virgin females for
mating, and female of guppy fish preferred large males for mating over the smaller ones and
orange males over the dull coloured males. The female of guppy fish were found to copy the
mate choice behaviour of other female in competition.
Like female guppy fish, the males also had distinct choice for females of large size
and a reproductive stage. The males showed maximal preference for mature virgin and
bearer-unmated females. When two males compete for a virgin or bearer-unmated female,
the first male showed, in majority of the cases, sigmoid display whereas second male in
majority cases resorted to sneaky mating attempts. The same trend was followed in case of
females with other reproductive stages.
Young males of guppy fish (up to 4 weeks old) spent most of their time in feeding,
which was reduced gradually with the age (size) of the fish. When a virgin mature female
was provided to a male, the young males engaged mostly in feeding whereas mature males
engaged in the pursuit of females. When multiple females were provided to a male, the latter
involved more and more in the chasing of females. The present feeding level of the males
also influenced the future feeding and courtship behaviour of the males.
Female fishes in all the reproductive stages, if kept alone, spent most of their time in
feeding. Presence of males severely influenced the time budget of female guppy fishes.
Variation in sex ratio was found to influence the fecundity in female guppy fish. An
optimum 1: 3 sex-ratio resulted into maximum fecundity in the females of this fish. All the
female showed almost equal gestation period before giving birth to the young ones (range
21-25 days). The fecundity, though could not reach at optimum level as realized in previous
experiment, yet it was uniform (about 58) in all the four types of aquaria. The survival of
young fry and young fishes in aquarium design-II was significantly higher than those in other
three aquarium designs.
Description
Keywords
Beverages, Biological phenomena, Sexual reproduction, Developmental stages, Research methods, Selection, Budgets, Reproductive stage, Breeds (animals), Sets