Combined effects of temperature and prey (Brachionus angularis) density on life-table demography and population growth ofAsplanchna brightwelli(Rotifera)

Abstract

-Predator-prey interactions play major and direct roles in the structuring of zooplankton communities. Asplanchna usually predates ciliates, rotifers, cladocerans and sometimes even copepods, its predation may drive not only the ecological, but also the evolutionary dynamics of prey populations. In the present study, the life-table demography and the population growth of Asplanchna brightwelli were investigated at four temperatures (16, 20, 24 and 28 xC) using Brachionus angularis as prey at four densities (10, 20, 30 and 40 ind.mL x1 ). The results showed that temperature affected significantly all the life-table demographic parameters (age-specific survivorship and fecundity, average lifespan, life expectancy at hatching, generation time, net reproductive rate and intrinsic rate of population increase) and the population growth rate obtained from the population growth studies, prey density affected the generation time, the net reproductive rate, the intrinsic rate of population increase and the population growth rate, and the interaction between temperature and prey density affected the generation time and the population growth rate. Both the average lifespan and the life expectancy at hatching were the longest at 16 xC, the generation times were longer at lower temperatures (16 and 20 xC) and higher prey densities (30 and 40 ind.mL x1 ), the net reproductive rates were higher at lower temperatures (16 and 20 xC) and 20-40 ind.mL x1 of B. angularis, and the population growth rates were higher at 20 xC under 20-40 ind.mL x1 of B. angularis.

Differences in life history characteristics among three sympatric evolutionary species of theRotaria rotatoriacomplex

“…Rotaria rotatoria is an asexual freshwater bdelloid rotifer, which is the largest Metazoan group that reproduces using only parthenogenesis (Ricci & Melone 2000;Mark Welch & Meselson, 2000, Fontaneto et al 2008Birky 2011). A large number of investigations dealing with ecological and evolutionary responses of monogont rotifers to temperature have recently been conducted because of their highly susceptibility to physical and chemical changes in their environment due to their small size and peculiar parthenogenetic reproduction (Miracle & Serra 1989;Snell et al 1991;Nogrady et al 1993;Xiang et al 2010;Huang et al 2012;Pan et al 2014). However, few studies are available on the life history characteristics and population dynamics of bdelloid rotifers (see Ricci 1983Ricci , 1991Lebedeva & Gerasimova 1987;Ricci & Caprioli 1998;Santo et al 2001;Ricci & Covino 2005).…”