Age, mortality, fertility, and individual diversities in the Rotifer Proales sordida gosse. II. Life‐history in relation to mortality and fecundity

Lifespan and Fecundity Patterns in Rotifers: The Cost of Reproduction

“…Consequently, a given amount of reproductive effort in older age classes is likely to increase the probability of mortality more than the same reproductive effort in younger age classes. Similar results were reported by Jennings and Lynch (1928) for another rotifer.…”

Measuring the Cost of Reproduction. Ii. The Correlation Structure of the Life Tables of Five Freshwater Invertebrates

“…It is not yet clear, even in the intensively studied nematode Caenorhabditis elegans (Hirsh, 1979), to what extent this determinism applies to the germ line. However, reproduction often ceases completely when a certain number of eggs have been produced, though the individual may survive for a considerable period after the extrusion of the last egg, as in the rotifers Proales sordida (Jennings and Lynch, 1928), P. decipiens (Noyes, 1922), Platyias patulus (Bell, 1983) and Philodina (present work). In the gastrotrich Lepidodermella squammata surviving females produce four eggs (Sacks, 1964; occasionally five according to Brunson, 1949), while Chaetonotus tachyneusticus produces only two (Brunson, 1949), regardless of lifespan or ration.…”

“…The coefficient of variation of total egg production is very low in Lepidodermella (CY= 19.0, Sacks, 1964 Table 1) and Proales decipiens (CY = 13.8, Noyes, 1922 Table 2, June series). It is rather greater in Proales sordida (CY = 34.2, Jennings and Lynch, 1928 Table 2) because the frequency distribution is negatively skewed, but much greater in Platyias (CY = 56.8), the frequency distribution being very broad. Thus we find a strong autocorrelated negative relationship between reproductive rate and longevity in Lepidodermella, a weaker but still negative relationship in Proales, and a very weak, or even positive, trend in Platyias.…”

“…Two series, each of 50 individuals, are differentiated by solid and hollow symbols. C. Rotifer Proales sordida (Jennings and Lynch, 1928 Since Philodina has a highly determinate life history, with reproduction plunging steeply from about two eggs per 10 days during ages 20 through 80 days to nearly zero by day 100, the negative relationship between fecundity and longevity observed within clones of this organism is more economically explained as a statistical artefact arising from reproductive determinism than as an instance ofreproductive cost. The same objection can be lodged against any similar study of organisms with determinate growth, including the widely-cited observations on the rotifer Asplanchna brightwelli made by Snell and King (1977).…”

Measuring the Cost of Reproduction. I. The Correlation Structure of the Life Table of a Plankton Rotifer

“…Since the age of the founding individual was not known, it played no part in the experiment other than helping to create a clone of 24 individuals. The age of the founder might nevertheless create variance between clones, since the life histories of offspring are known to be affected by maternal age in rotifers (Jennings and Lynch, 1928;Lansing, 1948). However, only a few individuals in each clone were offspring of the founder itself, the rest being more distant descendents, and neither longevity nor total fecundity varied systematically with the number of generations separating individuals from the founder.…”