Interaction Between Macrophytic Biomass and Insect Biomass in Wetland of West Bengal

摘要

The present paper deals with the interaction between monthly macrophytic biomass and Insect biomass during the period January 2002 to December 2002. A gradual increasing trend in macrophytic biomass production was observed during winter month. Ephemeroptera and Odonates were more abundant during summer months than in winter and monsoon. Ephemeroptera were absent in June and July in all wetlands. Hemipterans were recorded maximum during winter months as compared to other seasons, whereas Coleopterans were found to be more or less, evenly distributed throughout the year. In Eichhomia crassipes, it was maximum (120.4 g/m super(2)) in May in Khiramari bee! and Coleoptera biomass also maximum (2.4 g/m super(2)) in the same month. Nelumbo nucifera was minimum (18.4 g/m super(2)) in January in Krishna Sayer lake and Coleoptera biomass also minimum (0.0001 g/m super(2)) in the same month. Odonates and Ephemeropterans were correlated positively and significantly with submerged macrophytic biomass (Ceratophyllum demersum and Vallisneria spiralis) but their correlation with emergent (Altemanthera philoxeroides and Nelumbo nucjfera) macrophytic biomass were negative but significant. Hemipterans and Dipterans may be considered as comparatively less associated group with macrophytes. On the degree of interaction and association of insects with macrophytes, the former may be categorized into not interacted, strongly interacted, less interacted groups. Not interacted groups of insects with the macrophytes were Hemiptera and Diptera. The strongly interacted insects were Odonata, Ephemeroptera and Coleoptera. The less interacted groups of insects belonging to the order Hemiptera (Ranatra, Laccotrephes, Diplonychus), Coleoptera (Laccophilus, Canthydrus, Amphiops, Berosus) and Diptera (Chironomids).