Impact of Temperature and Notonecta predation on Cyclomorphosis in Daphniapulex: A Field Study in Subtropical environment, Jammu, India

摘要

The present study was carried out to find the impact of temperature and predation on cyclomorphosis in Daphnia pulex in a shallow pond with subtropical climatic conditions. Average values for carapace length and tail spine length were recorded to be 1.28 mm ± 0.143 and 0.529 mm ± 0.073 respectively during whole period of study. The length of carapace and tail spine were distributed over a very wide range of values during period of low temperature (10-24°C) as compared to the high temperature period (25-30°C). The results indicated that though D. pulex didn't exhibit the characteristic cyclomorphic traits like crest enlargement but body allometry showed certain variations among two different seasons with temperature difference of 22°C which has suggested producing cyclomorphic/phenotypic alterations. Regression analysis revealed that temperature exerted a highly significantly impact on carapace length in D. pulex. However, predation of Notonecta sp. on the D. pulex was not observed to show any direct phenotypic implications on the individuals.