The influence of olfaction on exploratory behaviour in the paradise fish (Macropodus opercularis L.)

We studied the role of olfaction on the exploratory behaviour of the paradise fish. Intact animals showed habituation of exploratory behaviour toward a heterospecific fish after five consecutive encounters. Fish with olfactory nerves destroyed spent significantly longer time with exploration compared to the control even at the fifth encounter. We suggest that olfactory inputs have a strong influence on exploratory behaviour.     

Behavioural elements of the paradise fish (Macropodus opercularis). II. A functional analysis

The effects of various environmental influences, such as presence of a living predator, dominant conspecific or frightening artificial stimulus, on particular behavioural elements of the paradise fish (Macropodus opercularis) were studied. It has been found that certain sets of the elements are manifested as organizational complexes which characterize a certain mood or form of defensive behaviour. The compound elements of these complexes seemed to be partly interchangeable, partly under environmental control. The main behavioural complexes of the paradise fish were the Territorial complex characterizing the peaceful, home-living animal, Emotionality complex appearing in case of immediate and past danger, Active and Passive defense complexes which represent alternatives in defense, depending on particular stimulus settings. Some supporting evidence for these behavioural complexes are presented and discussed.     

Diallel genetic analysis of the elements of paradise fish's (Macropodus opercularis L.) behavior in familiar and novel situations

Elements of the paradise fish's ethogram were recorded in 1 familiar and 3 different unfamiliar situations and the inheritance of these behavioral elements was investigated employing a five times replicated diallel cross between 3 inbred strains. A generalized Hayman Analysis of Variance and a Variance Covariance Analysis were performed to estimate genetic effects and parameters, such as, additive genetic variance, different sorts of dominance variance, reciprocal effects, direction and degree of dominance, ratio between the frequency of dominant and of recessive alleles, minimum number of effective factors and heritabilities, etc. Knowing the genetic architecture, we make inferences about the possible evolutionary past of the behavioral elements and explain why selection might favor certain types of paradise fish's behavior in particular circumstances. In several cases a possibility of "monogenic" inheritance emerged. We explain this finding and conclude that in a cross experiment where the inheritance of phenotypical units are investigated by employing only a few genetically different strains this result may be expected.     

Behavioural elements of the paradise fish (Macropodus opercularis). I. Regularities of defensive behaviour

Elements of behaviour were described for the paradise fish on the basis of the topography, location and orientation of the animal observed in various seminatural and laboratory environments. Correlations and repeatability of the parameters of observation were analyzed. Environmental influences, such as periods of the day, housing, feeding, raising conditions, presence of various frightening stimuli and species, and strain differences, were studied. Several functional connections were found among the behavioural elements.     

Genotype-environment interaction in passive avoidance learning of the paradise fish (Macropodus opercularis)

Passive dark avoidance conditioning and effects of the presence and absence of a fish-like dummy on the training process were studied in four inbred strains of paradise fish. Strain differences were found in the shuttle activity during habituation trials, and in the sensitivity to the mild electric shock punishment. The presence or absence of the dummy in the punished dark side of the shuttle box had a genotype-dependent effect on the measures taken during the conditioning process. The statistical analysis of the learning curves revealed differences in the way the strains varied in the different environments, i.e. genotype--environment interaction components of variances were identified. The results are discussed in the light of previous investigations and their implication in further genetic analysis.     

Prostaglandin-F2 alpha stimulates reproductive behavior of female paradise fish (Macropodus opercularis)

The function of prostaglandin-F2 alpha (PGF2 alpha) in reproductive behavior of adult female paradise fish (Macropodus opercularis) was evaluated. In experiment 1, females were allowed to spawn normally with a male and were left with that male until the following day when testing occurred. Subjects were then randomly assigned to one of three groups: PGF2 alpha (N = 8), vehicle control (N = 3), or a handling control (N = 3); for testing, females were removed, injected, then returned to the same tank. Seven of the eight subjects injected with 500 ng PGF2 alpha initiated complete reproductive behavior following injection. Vehicle and handling control subjects did not show any female reproductive behaviors. Prostaglandin-induced increases in sexual behaviors were seen from 15 to 75 min after the injection and were maximal approximately 45 min postinjection. In experiment 2, mature but unspawned (and presumably sexually naive) females were placed for 1 hr with males which were actively nestbuilding and parenting, following which subjects were either injected with PGF2 alpha (N = 6) or given a vehicle injection (N = 6). Experimental females did not behave differently from control females. Neither groups was observed to approach the male or initiate spawning behaviors following treatment; all subjects in both groups spawned on the following day. In experiment 3, sexually mature females were given extended familiarity with the male and the test tank. Pairs which had not spawned after 6 days (unspawned) were randomly assigned to experimental (N = 6) or control (N = 5) groups. Pairs which had spawned 1 day previously (N = 6) formed a "prespawned" comparison group. Females from the experimental and prespawned groups were injected with PGF2 alpha (500 ng), while the control females received a vehicle injection. Half of the "prespawned" females performed spawning acts while none of the unspawned or control females did so. Detailed behavioral analyses showed little or no effect of PG treatment, despite greater familiarity with the male. In experiment 4, females were placed with males and observed until the early signs of spawning, at which time they were injected with indomethacin (a PG synthesis inhibitor) or vehicle. The behavior of females treated with 35 micrograms (N = 3) or 70 micrograms (N = 6) of indomethacin was unaffected by indomethacin and largely indistinguishable from controls (N = 6). In summary, exogenous prostaglandins reinstate sexual behavior in female paradise fish. However, responsiveness to prostaglandins is influenced by prior sexual experience.(ABSTRACT TRUNCATED AT 400 WORDS)     

Artifical gynogenesis and mapping of gene-centromere distances in the paradise fish,Macropodus opercularis

Summary An efficient method has been developed for the production of gynogenetic paradise fish in order to obtain genetically homogeneous strains in a relatively short period. Diploidy of the gynogenetic embryos was restored by inhibition of the second meiotic division, and consecutive generations of normal, fully viable offspring were reared. Crossing-over frequencies and the relative positions of four marker loci were determined by analysing electrophoretic patterns of serum transferrin and esterases in the gynogenetic progeny of heterozygous females.     

Effect of the components of the physical environment on escape behaviour of the paradise fish (Macropodus opercularis)

Physical features of a seminatural environment on provoking various defence behaviour elements of the paradise fish were studied. It was found that most escape behaviour forms were under the control of visual stimuli. Transparent physical space induced escape and inhibited jumping. While the latter was induced by the presence of vertical untransparent surfaces. Dark places usually were avoided by the paradise fish. Placed into an unfamiliar environment in the presence of different escape routes the paradise fish seemed to make decisions after careful comparison of alternatives.     

Polymorphism and inheritance of serum esterases and beta-globulins in the paradise fish (Macropodus opercularis; Anabantidae)

Electrophoretic variants of serum esterases and beta-globulins in two subspecies of paradise fish (Macropodus opercularis) were studied. Four esterase loci (Est-1, Est-2, Est-3 and Est-4), a single transferrin (Tf) and another major beta-globulin locus (Bg) were identified by segregational analysis. Est-3 seems to be a monomorphic locus. Three alleles of Est-1, two of Est-2, two of Est-4, four of Tf and two alleles of Bg were found in the laboratory population. None of these loci were closely linked. Electrophoretic patterns of F1 hybrids confirmed the monomeric structures of each of the studied proteins. Allelic segregation at the Tf and Bg loci was normal in F2 and backcross populations. In crosses of the two Macropodus subspecies there were deviations from Mendelian ratios because of missing recombinant esterase phenotypes. Each of these would have been homozygous Est-2f/f. We suppose that Est-2f/f causes lethality in the early phase of development, except in the Est-1c/c, Est-2f/f combination characteristic of the parental subspecies M.o. concolor.     

The behaviour of the paradise fish (Macropodus opercularis) in two different open-fields. A correlation study

The behaviour of the paradise fish in a traditional "closed" and in a new "transparent" open-field was investigated. The traditional way of measuring ambulation scores was extended by recording ethologically defined behaviour units. The correlations found between the scores measured in the "closed" field and those measured in the "transparent" field are discussed in this paper.     

Die Auspigmentierung von Schwanzflossenregeneraten bei Macropodus opercularis L. (Teleost.)

Ohne ZusammenfassungDissertation der Mathematisch-Naturwissenschaftlichen Fakultät der Friedrich Schiller-Universität zu Jena. Die Arbeit ist durch Herrn Prof. Dr. V. Franz angeregt worden.     

Polymorphism and inheritance of serum esterases and β-globulins in the paradise fish (Macropodus opercularis; Anabantidae)

Electrophoretic variants of serum esterases and β-globulins in two subspecies of paradise fish ( Macropodus opercularis ) were studied. Four esterase loci ( Est-1, Est-2, Est-3 and Est-4 ), a single transferin ( Tf ) and another major β-globulin locus ( Bg ) were identified by segregational analysis. Est-3 seems to be a monomorphic. locus. Three alleles of Est-1 , two of Est-2 , two of Est-4 , four of Tf and two alleles of Bg were found in the laboratory population. None of these loci were closely linked. Electrophoretic patterns of F₁ hybrids confirmed the monomeric structures of each of the studied proteins. Allelic segregation at the Tf and Bg loci was normal in F₂ and backcross populations. In crosses of the two Macropodus subspecies there were deviations from Mendelian ratios because of missing recombinant esterase phenotypes. Each of these would have been homozygous Est-2^f/f . We suppose that Est-2^f/f causes lethality in the early phase of development, except in the Est-1^c/c, Est-2^f/f combination characteristic of the parental subspecies M.o. concolor .     

Behavior-genetic analysis of the paradise fish (Macropodus opercularis). IV. Behavioral unit analysis of the response to novelty using recombinant inbred strains

Frequencies and relative durations of eleven ethologically defined behavioral units were measured on paradise fish of two inbred strains and 9 recombinant inbred lines derived from their cross and then maintained under inbreeding. Significant genotype-dependent differences were found in all but one behavior units. Strain distribution patterns showed polygenic genetic determination of all units, and in several cases non-allelic genic interactions seem to contribute to the variation. Additive and interaction components of the progenitor means and minimal number of effective factors were estimated for each behavior unit.     

Behavior-genetic analysis of the paradise fish, Macropodus opercularis. III. Genetic analysis of the response to novelty using recombinant inbred strains

Fifteen behavioral measurements were taken on paradise fish of two inbred progenitor strains and of 16 recombinant lines derived from their cross and maintained under inbreeding with gynogenesis and sib-mating. Univariate and multivariate analyses showed significant differences among the RI means on all measures. Four combined variables extracted by principal component analysis showed that there were common sources of a large part of the behavioral variability measured in the arbitrarily designed test situations. There were no separate subgroups of the RI strain means, and overlapping ranges point to a polygenic genetic determination of the studied behavioral phenotypes. A biometrical analysis of the distribution pattern of recombinant lines and the progenitor strains showed that in several characters non-allelic genic interactions made a significant contribution to the variation. Additive and interaction components of the mean, the heritabilities and the minimum number of effective factors were estimated for all studied behavioral phenotypes, and the combined variables as well.     

Conditions for recognition of a physical space as two compartments by the paradise fish (Macropodus opercularis, Pisces, Anabantidae).

By using a series of aquaria which were more or less separated into two compartments by a "gate" made of plastic or glass strips, we studied how paradise fish changed their patterns of movement relative to the nature of the gates. We found that opaque plastic gates were well recognized by the paradise fish (Macropodus opercularis) even if the strips were very thin, but that they only changed their pattern of movement when the strips exceeded a certain width. Thus, paradise fish appear to be able to distinguish a physical space of the same size as consisting of either one or two compartments, depending on the material (transparency) and width of the dividing strips.