Parental egg care behavior and fanning activity for the orange chromide,Etroplus maculatus

Synopsis

Physiological studies revealed that agitation (simulated fanning) of the brood results in increased oxygen consumption, increased developmental rate and general promotion of brood success. It was also found that the more intense the agitation (excursions per minute) the greater the metabolic rate is enhanced. Embryos exposed to continual agitation hatched approximately twenty hours in advance of non-agitated eggs. Temporal studies of fanning activity inEtroplus maculatus showed significant differences between pairs breeding in colonial situations as compared to those breeding in isolation. Parental behaviors were recorded throughout egg care until hatching. Two types of ventilatory behaviors were described: active fanning and passive fanning. Pairs breeding in isolation invested more time in long passive bouts and less time in short active bouts. Conversely, colonial parents fanned predominately with short active bouts and displayed no prolonged passive fanning. Surprisingly, no differences were apparent in either reproductive success or hatching time between isolated and colonial pairs in this study. Orange chromides readily nested in two extremely different situations. They also displayed significantly different fanning regimes, behavioral time budgets and transitions of behavior; yet they were equally successful. Parental orange chromides can modulate their ventilatory activities in response to the contingencies of their nesting situation which ultimately allows them maximization of reproductive success.