Abstract
For many years, ecology was dominated by studies of communities focussing on above-ground systems, whereas the soil was viewed as a "black box". Much of the early research also concentrated on bi-trophic interactions e.g. interactions involving plant-herbivore and herbivore-parasitoid (or predator) associations. In recent years, it has become evident that, in order to unravel community-level processes, research should include a greater number of potential interactions. For example, recent experiments have revealed that above-ground (AG) and below-ground (BG) communities may interact, by influencing changes in the primary and secondary chemistry of a shared plant species. However, few of these studies have examined the effects of root herbivory on developmental parameters in higher trophic levels aboveground, such as parasitoids and their hyperparasitoids and vice versa. Here, we aim to investigate the extent to which the presence or absence of BG herbivores influences developmental and behavioural processes of specialist and generalist herbivores, parasitoids and hyperparasitoids aboveground and how aboveground herbivory influences the development of a parasitoid of a belowground herbivore. We aim at investigating four hypotheses: (1) The presence or absence of AG or BG herbivores affects the developmental performance of parasitoids (and hyperparasitoids) in the opposite compartment, through changes in plant and host quality. (2) BG herbivore damage differently affects the developmental performance of generalist and specialist herbivores and their antagonists. (3) Oviposition behaviour of AG parasitoids and hyperparasitoids under controlled conditions is affected by the amount of feeding damage by herbivores in the opposite compartment as these affect host and plant quality. (4) Oviposition behaviour of AG herbivores, parasitoids and hyperparasitoids in the field is affected by the amount of feeding damage by BG herbivores as these affect host and plant quality.
Netherlands