Intraspecific and interspecific of the competition between Spodoptera frugiperda and Spodoptera exigua indoors
Spodoptera frugiperda and Spodoptera exigua are major pests of crops in our country,and they share many common host plants.In order to understand the competitive relation between S.frugiperda and S.exigua,the intraspecific and interspecific larval interaction between these two pests were observed under food plentitude as well as food deficiency condition.The competitive behaviors of larvae of S.frugiperda and S.exigua with different initial newly hatched larvae population densities when they appeared simultaneously in the same ecological niche were studied.The results showed that wriggle was the predominant intraspecific competitive behavior in S.frugiperda in all the interactive scenarios,with the highest mean wriggle frequency of 8.57±0.49 times per 30 min recorded in the scenarios of 3rd vs.5th instar of this species without food condition.The number of aggression and defense behaviors of S.frugiperda with food treatment was lower than that without food treatment.In the interactive scenario between S.frugiperda and S.exigua,head touching and wriggle were the most frequent behavior in both pests without food treatment.The highest frequency of head touching of 5.03±2.43 times per 30 min and wriggle of 18.47±5.92 times per 30 min,were recorded when the 4lh instar larvae S.frugiperda competed with the 5th instar larvae S.exigua.In addition,S.frugiperda had a higher survival rate in the interactive scenario of the same instar of S.frugiperda and S.exigua,and the older one had higher survival rate in the interactive scenario of different instar of these two pests.The survival rate of both species was higher with food than without food.In the indoor simulation of population competition,the survival rate of S.frugiperda and S.exigua populations decreased with the increase of coexisting time.Repeated measurement analysis of variance showed that the survival rate of 5 newly hatched larvae of S.frugiperda+40 newly hatched larvae of S.exigua was not significantly affected by the coexistence time,also the survival rate of them was no significant difference.Repeated measurement analysis of variance showed that the coexistence time of 5 newly hatched larvae of S.frugiperda+40 newly hatched larvae of S.exigua had no significant effect on the survival rate of S.frugiperda,but the survival rate of S.exigua larvae was significantly affected by the coexistence time.In other combinations,the coexistence time significantly affected the survival rate of S.frugiperda and S.exigua larvae.Among them,the survival rate of 40 newly hatched larvae of S.frugiperda+40 newly hatched larvae of S.exigua was significantly different.The survival rate of S.frugiperda was significantly higher than that of S.exigua,resulting in possible replacement of S.exigua with S.frugiperda.This study helps clarify the population competition and replacement between these two pests and formulate scientific control strategies.
万方数据
维普
