Facial Display Experiment

Decent Essays
As the hypothesis predicted, the rate and the duration of facial displays do influence the outcome of a contest between two male Betta splendens. In fact, it was found that the male which carried out more facial displays for longer was, on average, defined as the winner of a dyadic conflict.
The average results seem to reinforce this hypothesis, although a few results went against it (e.g., the fish in tank 13), which might have been due to some limitations of the experiment. The heater on the left side of the tank might have interfered with the response from the left fish as it consists in a physical object and might have reduced the attention of the fish especially during the first part of the experiment. This means that there might have
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Using threats without escalating to a more damaging offense might be a way of economising effort even though the signalling activities still require a significant amount of energy. However, studies show that the winning individuals are faster at producing energy, as their metabolic rates are faster than in losers, although this might also be because subordinate individuals consume less energy as they produce less facial displays. This is very important as they cannot show themselves as being superior (Nìdia Castro, Albert F.H. Ros, Klaus Becker and Rui F. Oliveira, 2006). Duration might be a greater determinant of dominance as it could require more energy than does the rate. Therefore, it could be thought that the fish on the left side of tank 13 might have won the fight as it spent less time in facial display against its mirror image thus saving energy, but studies show that energy costs are usually reflected the night after the contest as opposed to during the conflict (Nìdia Castro, Albert F.H. Ros, Klaus Becker and Rui F. Oliveira, 2006). In conclusion, energy costs from the first part of the experiment do not influence the fish versus fish…show more content…
Nonetheless, in the natural environment of Betta splendens the results might have been different as many external factors might alter the outcome. In fact, in the natural environment aggression is mainly used in order to get mating opportunities as the dominant male is seen as persisting whilst the subordinate flees. This conveys genetic superiority to a potential female mate and therefore suggests that they are breeding fighting fish and will be the best-fitted to defend the area around the nest (Doutrelanta C, McGregora PK, Oliveirab RF, 2001). Studies show that the agonistic behaviour of a Siamese fighting fish is influenced by the effect of an audience. With a female audience, males tend to show agonistic displays that are not so aggressive, as a recent study shows that females tend to prefer less aggressive individuals (Teresa L. Dzieweczynski, Alyssa M. Russell, Lindsay M. Forrette and Krystal L. Mannion, 2014). However, they tend to have more aggressive contact (e.g., biting) with their opponents in the presence of males, which eavesdrop on the display. The behavior of the fish might have also been influenced by the presence of a nest or of progeny in their territory as studies show that aggressiveness increases in males who need to defend nests
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