Abstract:

The aim of the investigation was to determine length-weight relationships (LWR) as an alternative method for determining insect biomass. The LWR were calculated for seven aquatic beetles species caught at Choghakhor Marsh in Iran. Individuals’ samples were dried at 60℃ for 24 h, cooled in a desecrator, and weighted to the nearest 0.001 g. Each beetle was also measured for body length to the nearest 0.1 mm. The parameters of LWR (a and b values) were estimated by linear regression on the transformed equation: Log W=log a + b log L. The results indicated that the parameter b on LWR varied between 2.315 and 3.117. Significant LWR with high correlation coefficient (r²) were found for all species examined. The obtained relations can be used in the determination of the weight of the beetle and they are also useful in addressing many ecological questions. The application of the LWR presented here should be restricted to the observed length ranges.

Key words: Insects, Coleoptera, biomass, body length, body weight, marsh, Iran