Bacteria have developed an impressive ability to survive and propagate in highly diverse and changing environments by evolving phenotypic heterogeneity. Phenotypic heterogeneity ensures that a subpopulation is well prepared for environmental changes. The expression bet hedging is commonly (but often incorrectly) used by molecular biologists to describe any observed phenotypic heterogeneity. In evolutionary biology, however, bet hedging denotes a risk‐spreading strategy displayed by isogenic populations that evolved in unpredictably changing environments. Opposed to other survival strategies, bet hedging evolves because the (...) selection environment changes and favours different phenotypes at different times. Consequently, in bet hedging populations all phenotypes perform differently well at any time, depending on the selection pressures present. Moreover, bet hedging is the only strategy in which temporal variance of offspring numbers per individual is minimized. Our paper aims to provide a guide for the correct use of the term bet hedging in molecular biology. (shrink)

One of the major criticisms of optimal foraging theory (OFT) is that it is not testable. In discussions of this criticism opposing parties have confused methodological concepts and used meaningless biological concepts. In this paper we discuss such misunderstandings and show that OFr has an empirically testable, and even well-confirmed, general core theory. One of our main conclusions is that specific model testing should not be aimed at proving optimality, but rather at identifying the context in which certain types of (...) behaviour are optimal. To do this, it is necessary to be aware of the assumptions made in testing a model. The assumptions that are explicitly stated in the literature up to now do not completely cover the actual assumptions made in testing OFT models in practice. We present a more comprehensive set of assumptions. Although all the assumptions play a role in testing models, they are not of equal status. Crucial assumptions concern constraints and the relation between fitness and currency. Therefore, it is essential to make such assumptions testable in practice. We show that a more explicit relationship between OFT modelling and evolutionary theory can help with this. Specifically, phylogeny reconstruction and population dynamic modelling can and should be used to formulate assumptions concerning constraints and currencies. (shrink)

One of the major criticisms of optimal foraging theory (OFT) is that it is not testable. In discussions of this criticism opposing parties have confused methodological concepts and used meaningless biological concepts. In this paper we discuss such misunderstandings and show that OFr has an empirically testable, and even well-confirmed, general core theory. One of our main conclusions is that specific model testing should not be aimed at ‘proving’ optimality, but rather at identifying the context in which certain types of (...) behaviour are optimal. To do this, it is necessary to be aware of the assumptions made in testing a model. The assumptions that are explicitly stated in the literature up to now do not completely cover the actual assumptions made in testing OFT models in practice. We present a more comprehensive set of assumptions. Although all the assumptions play a role in testing models, they are not of equal status. Crucial assumptions concern constraints and the relation between fitness and currency. Therefore, it is essential to make such assumptions testable in practice. We show that a more explicit relationship between OFT modelling and evolutionary theory can help with this. Specifically, phylogeny reconstruction and population dynamic modelling can and should be used to formulate assumptions concerning constraints and currencies. (shrink)