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Herbivores and the evolution of the semelparous perennial life‐history of plants
Author(s) -
Klinkhamer P. G. L.,
Kubo T.,
Iwasa Y.
Publication year - 1997
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1046/j.1420-9101.1997.10040529.x
Subject(s) - semelparity and iteroparity , biology , herbivore , perennial plant , reproduction , life history theory , ecology , life history
The relationship between a plant and its potential enemies changes drastically after reproduction has started. Using a dynamic modelling approach we study the effects of herbivores and pathogens, that are attracted by reproducing plants, on optimal allocation of resources, and life‐history strategies. We assume that the level of attack increases with the investment in reproduction, which may lead to a reduction of current years reproductive success, a reduction of storage efficiency or an increase of plant mortality. If herbivores or pathogens attracted by flowering plants mainly reduce current years reproductive success, the optimal life‐history is annual or iteroparous perennial if the attack is an all or nothing event. If the level of consumption increases with the number of herbivores attracted, the optimal life‐history is most likely iteroparity with or without mast years. Only under very restricted conditions this may lead to semelparity. If herbivores mainly reduce the efficiency of the resources stored for next year, the optimal life‐history is iteroparity. If herbivores mainly reduce survival, the optimal solution is likely to be mast years or semelparity. For parameter values that are realistic for Cynoglossum officinale , a semelparous perennial from calcereous soils, the model predicts that reproduction should start in the third year and that 99% of the available resources at the end of season should be invested in reproduction and only 1% saved for growth next year. With such an investment only c. 1% of the plants would survive after reproduction, so the optimal life‐history is close to semelparity. For the small fraction of plants that reproduce more than once, years of vegetative growth only and years with reproduction should alternate. Multiple reproduction is rare in C. officinale . However, such a life history is very common for plants known as semelparous perennial. Although the available empirical evidence is, as yet, circumstantial rather than conclus ive we propose that reproduction related mortality mediated through herbivores or pathogens may play a role in the evolution of the semelparous perennial life‐history.