Journal of Environmental Biology

Temperature-dependent demographic differences in sessile rotifers of the genus Limnias (Rotifera: Gnesiotrocha)

Paper received: 12.11.2018??????????????????? Revised received: 24.01.2019????????????????? Re-revised received: 28.02.2019???????????? Accepted: 09.03.2019

Authors Info

M.A. Jim?nez-Santos¹,

S.S.S. Sarma²* and S. Nandini²

¹Posgrado en Ciencias del Mar y Limnolog?a, Universidad Nacional Aut?noma de M?xico, CP 04510, Mexico

²Laboratory of Aquatic Zoology,

National Autonomous University of Mexico, CP 54090 Tlalnepantla, Mexico

*Corresponding Author Email :

sarma@unam.mx

Abstract

Aim: Rotifer research on sessile taxa has received less attention because they are not easy to identify in fixed samples. In the Lake Xochimilco, a Ramsar site in Mexico City, three morphotypes of L. ceratophylli and a single morphotype of L. cf. melicerta occur in different densities. The aim of this study was to test if temperature was responsible for the differences in the population densities of these morphotypes. ??  

Methodology: The present study was carried out using population growth method consisting of 4 treatments (3 morphotypes of L. ceratophylli and one of L. cf. melicerta) at 20 and 25?C. Experiments were carried out in 50 ml glass jars containing 25 ml synthetic medium with Chlorella vulgaris as food. The population growth rates (r) were derived. Analysis of variance (ANOVA) and post-hoc tests were used to quantify the intra-and interspecific differences in the population growth rates. 

Results: The temperature levels for optimal population growth rates differed among the morphotypes of same species. At 20?C, the morphotype 1 had the highest r (0.23 d^-1) similar to that of L. cf. melicerta, while morphotype 3 had the lowest (0.15 d^-1). For L. cf. melicerta, the r was higher at 25?C than at 20?C. Of three morphotypes of L. ceratophylli, morphotype 3 had the highest r at 25?C similar to that of L. cf. melicerta at same temperature.

Interpretation: There were significant differences among growth patterns within the morphotypes of L. ceratophylli, depending on culture temperature. These trends highlight the relative importance of environmental variables in differentiating morphotypes of a sessile species complex which could explain their possible seasonal changes in the natural waterbodies.

Key words: Limnias, Morphotypes, Ramsar site, Sessile rotifers, Temperature dependent

Copyright ? 2019 Triveni Enterprises. All rights reserved. No part of the Journal can be reproduced in any form without prior permission. Responsibility regarding the authenticity of the data, and the acceptability of the conclusions enforced or derived, rest completely with the author(s).