Life history adaptation to demographic regime in laboratory-cultured Tisbe furcata (Copepoda, Harpacticoida)
Bergmans, M. (1984). Life history adaptation to demographic regime in laboratory-cultured Tisbe furcata (Copepoda, Harpacticoida). Evolution 38(2): 292-299. https://dx.doi.org/10.2307/2408488 In: Evolution. Society for the Study of Evolution: Lancaster. ISSN 0014-3820; e-ISSN 1558-5646, more |  |
| Keywords | Laboratory culture
Life history
Tisbe furcata (Baird, 1837) [WoRMS]
Marine/Coastal |
| Abstract | A laboratory population of Tisbe furcata (Copepoda, Harpacticoida) with a 35-generation history of stable population size was examined for life history adaptations to demographic stationarity. Survival and fecundity schedules and individual fitness parameters were measured; a standard being provided by three accessions of the wild source population. Tisbe furcata responded to density regulation by increasing its potential net reproductive rate, Ro This result is in agreement with the theory of fitness in age-structured populations, though in contradiction with intuitions based on the r-Kparadigm. The physiological mechanisms through which Ro is raised are high age-specific fecundity, delayed senescence and, primarily, increased frequency of egg sac production. The reasons for the adoption of the latter mechanism rather than other alternatives are analyzed. The cost of early reproduction is held responsible for differences between cohorts in the distribution of individual minimum generation times: (indirect) truncation-type selection in the case of Ro-selection is opposed to a (direct) symmetric pattern in the case of r-selection. This is one of the first papers reporting adaptive fine-tuning of the lxmx schedule in an equilibrium rather than r-selected population. |
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