Periodic Reporting for period 5 - COMPCON (Competition under (niche) construction)
Período documentado: 2023-05-01 hasta 2023-10-31
Data generated by COMPCON will strengthen the growing link between Ecology and Evolution, as it will test recent hypotheses concerning how individual variation, niche width, niche construction and competition interact to shape species distributions and trait evolution.
We also found large variation for intra and interspecific competitive ability, but again no correlation among traits. We are currently investigating whether specific combinations of these traits facilitate coexistence among these competitors, based on theoretical predictions.
Moreover, we found that tomato plants accumulate cadmium and that the response of the two species to this accumulation varies in shape and intensity and is altered by the presence of interspecific competitors. However, the change induced by the presence of the competitor is not in niche location or width, as expected by classical theory, but in the shape of the response.
Furthermore, we performed experimental evolution of spider mites on tomato plants with or without cadmium and with or without competitors, then tested how this evolutionary history affected the probability of coexistence in environments with and/or without cadmium. We found effects of the evolutionary history in some, but not all, cases, and a strong dependence of this effect upon the environment tested. These findings have important consequences for the effect of evolution in species interactions.
Finally, we performed experimental evolution of spider mites on tomato plants in which defences can be induced or suppressed or in plants where defences cannot be altered by spider mites, in presence or absence of competitors. We found that T. evansi, the suppressor, stopped suppressing when (a) evolving on plants where suppression has no effect and (b) evolving on plants with competitors. This suggests that suppression has ecological and physiological costs, a key finding for the understanding of herbivore-plant interactions.
We performed comprehensive tests of individual niche variation in the fundamental and the realized niche and their potential correlation. This data set is unique in that (a) few studies have addressed the genetic basis of niche width and (b) none has addressed potential correlations among the fundamental and the realized niche width at the individual level. We will subsequently test how variation in individual niche width affects coexistence.
The data concerning individual variation in niche construction revealed significant variation, which is very exciting. We found that such variation in niche construction led to longer persistence of the weaker competitor. We will performed experimental evolution to test whether the suppression of plant defences is maintained in an environment with cheaters or in which niche construction yields no benefit. We found that spider mites ceased suppressing plant defences in such environments, revealing a high cost of suppression, potentially shedding light on the low prevalence of this strategy in herbivores, despite high benefits.