Responses to stress of Caenorhabditis elegans populations with different reproductive strategies
Alda Alvarez, O., and Jager, T. and Kooijman, S. A. L. M. and
Kammenga, J. E. 2005. Responses to stress of Caenorhabditis
elegans populations with different reproductive strategies
Functional Ecology, 19: 656 - 664.
- Hermaphroditic and gonochoric reproduction are essentially
different reproductive strategies that may lead to diverging
population responses to adverse environmental conditions. Each
strategy implies different physiological mechanisms, which affect
life-history traits and represent different ways of dealing with
- We studied the performance of hermaphroditic vs gonochoric
strains in the nematode Caenorhabditis elegans exposed to cadmium
stress at the individual and population level.
- Under control conditions, the gonochoric strain started
reproduction earlier than the hermaphroditic strain at a smaller
size. This was due to an earlier switch from sperm to oocyte
production triggered by male sperm availability. Under cadmium
stress hermaphrodites showed a decrease in the size at onset of
reproduction, presumably as a strategy to maintain a high population
growth rate. In contrast the body size of gonochoric nematodes was
- A process-based model (DEBtox) was used as a tool for analysing
life-history data and calculating population growth rates. The model
fitted the data well using physiologically relevant parameters such
as ageing, survival or reproduction related parameters. The
simultaneous fit of all life-history traits was used to obtain
populations growth rate estimates.
- The differences between the two C. elegans strains were
reflected at the population level. Lower population growth rates, as
calculated by DEBtox, were found in the gonochoric strain, largely
determined by the proportion of males in the offspring.
- From the overall results we suggest that the differences found
between both populations are due to the reproductive strategy. Under
control conditions, CB strain (with gonochoric reproduction) does
not favour population growth rates in the short term due to faster
ageing and copulation costs on survival. Furthermore, in response to
stress this strain also showed lower performance than the N2
hermaphroditic strain, mainly due to a higher sensitivity of
survival to the stressor.
Erratum: Some infinity symbols in Table 1 converted into 8.