Above- and belowground herbivores influence each other mediated by the host plant. Most of the studies on this matter have been conducted in controlled and homogeneous laboratory conditions. However, the reality is that species interact within dynamic, heterogeneous and complex landscapes. Moreover, the dispersal capacity of species is obviously different. While plants and aboveground insect herbivores have the chance to move over long distances by means of flight or seed dispersal, belowground herbivores are limited in their movements. This situation results in an asymmetrical shifting mosaic in time of species interactions, where organisms are present in some patches and not in other. Nevertheless, it has never been addressed how species interactions, such as those of below- and aboveground herbivores, are affected by their own mobility within structurally complex landscapes and what are the evolutionary consequences for herbivory-related life history traits (e.g. plant toxin production and development of resistance against toxins by herbivores). We developed an individual based simulation model in which we addressed the effect of landscape structure on the population dynamics and the evolution of toxin production/resistance of a plant and two herbivores, an aboveground and a belowground. Simulations were run under different landscapes testing different mobility for the species, with belowground herbivores always having a very restricted movement and, conversely, a continuum of dispersal ranges for plant seeds and aboveground herbivores. The interaction between the plant and both herbivores was studied under a trade-off scenario where the multiplication of each of the three species was modified in time as a function of the development of toxins or resistance.
Results/Conclusions
