食蚊鱼昼夜摄食节律观察

以分时段采样法研究入侵物种食蚊鱼的夏季昼夜摄食节律。食蚊鱼夏季种群内有雌鱼、雄鱼和幼鱼三个不同的摄食类群,这三个类群的摄食节律差异明显。雌鱼摄食节律成双峰型,第一高峰在10:00,而最高峰在22:00,此时肠道食物团平均重量11.70±11.60mg,饱满指数为190.22±155.61。幼鱼也成双峰型,分别在6:00和18:00有两个摄食高峰,以清晨6:00为最高,肠道食物团平均重1.08±1.09mg,饱满指数为128.44±105.49。雄鱼则成单峰型,摄食高峰出现午后14:00左右,肠道食物团平均重0.71±0.96mg,饱满指数为71.80±107.65。食蚊鱼不同摄食类群间的摄食高峰交错出现,是其协调种内关系,降低种内竞争的一种有效行为机制。

Diel feeding rhythm of mosquito fish

Mosquito fish,an invasive species,was introduced into mainland China in 1927 and entered Guangzhou during 1960s.The diel feeding rhythm of mosquito fish taken from Ming Lake,an artificial lake in Jinan University in summer,2007 was investigated in this study.Population structure of mosquito fish in summer was very complex,consisting of female,male and larvae fish groups.These feeding groups had different feeding rhythm in this season.Female feeding rhythm showed two peaks at 10:00 and 22:00.The second peak was the highest,and the food in the fish gut was 11.70±11.60 mg and feeding index was 190.22±155.61 at that time.Larvae fish feeding rhythm had two peaks at 6:00 and 18:00,and the highest one peaked at 6:00,when the food in the gut was 1.08±1.09 mg and feeding index was 128.44±105.49.Male fish feeding rhythm had a single peak at 14:00,at which the food in the gut was 0.71±0.96 mg and feeding index was 71.80±107.65.Different feeding rhythms among these three feeding groups could reduce the intra-specific competition.