Tall herb herbivory resistance reflects historic exposure to leaf beetles in a boreal archipelago age-gradient

摘要: In this paper, we introduce the coevolution-by-coexistence hypothesis which predicts that strength of a coevolutionary adaptation will become increasingly apparent as long corresponding selection from an interacting counterpart continues. Hence, evolutionary interactions between plants and their herbivores can be studied by comparing discrete plant populations with known history herbivore colonization. We host plant, Filipendula ulmaria (meadow sweet), on six islands, in Bothnian archipelago subject to isostatic rebound, represent spatio-temporal gradient coexistence its two major herbivores, specialist leaf beetles Galerucella tenella Altica engstroemi. Regression analyses showed number traits important for insect-plant (leaf concentrations individual phenolics condensed tannins, height, G. adult feeding oviposition) were significantly correlated island age. First, tannins positively age, suggesting resistance increased after colonization continued increase parallel increasing time past coexistence, while height reverse negative correlation. Second, multi-choice experiment both oviposition consumption negatively Third, larvae performed poorly well-defended, older well less-defended, younger populations. Thus, no parameter assessed study falsifies hypothesis. conclude gradients present rising archipelagos offer unique opportunities address interactions, but care has taken abiotic (and other biotic) factors may interact complicated way.