The Community Ecology of Herbivore Regulation in an Agroecosystem: Lessons from Complex Systems

Abstract

Whether an ecological community is controlled from above or below remains a popular framework that continues generating interesting research questions and takes on especially important meaning in agroecosystems. We describe the regulation from above of three coffee herbivores, a leaf herbivore (the green coffee scale, Coccus viridis), a seed predator (the coffee berry borer, Hypothenemus hampei), and a plant pathogen (the coffee rust disease, caused by Hemelia vastatrix) by various natural enemies, emphasizing the remarkable complexity involved. We emphasize the intersection of this classical question of ecology with the burgeoning field of complex systems, including references to chaos, critical transitions, hysteresis, basin or boundary collision, and spatial self-organization, all aimed at the applied question of pest control in the coffee agroecosystem.

New forms of structure in ecosystems revealed with the Kuramoto model

“…It is satisfying that the Kuramoto model does seem to represent the underlying qualitative dynamics of the real system. Since this system is about pests of an important crop, it is obvious of potential practical importance that an approximate toy model such as this one can reflect the basic structure of this system as we have come to know it from over two decades of study [ 33 ]. There is a clear relationship between the number of nodes and the timing of the formation of synchrony groups, suggesting that a herbivore guild containing multiple species attacking it is likely to synchronize the whole group quite rapidly.…”

“…As interesting as the theoretical diversions of the basic model are, thus far there has not been an attempt at applying the Kuramoto framework to a real ecological system. Here, we use the well-documented system of pests and their natural enemies in the coffee agroecosystem [ 33 , 34 ] as a system in which predators/parasitoids/diseases attack four well-known pests of coffee and, therefore, can be viewed as a single system of oscillators. The four pests are (i) the coffee berry borer ( Hypothenemus hampei Ferrari), (ii) the coffee leaf miner ( Leucoptera coffeella Guérin-Méneville), (iii) the green coffee scale ( Coccus viridis ), and (iv) the coffee leaf rust fungus ( Hamaelia vastatrix Berk.…”

“…We diagram the basic system in figure 1 . It is critical to note that this rendering, although it includes top predators and parasitoids (those that eat the consumers of the prey), is a simplified rendering, emphasizing the direct energy transfer interactions and ignoring the well-known indirect higher order interactions [ 33 ]. Anticipated further studies will incorporate those more complex additions of reality.…”

Viewing communities as coupled oscillators: elementary forms from Lotka and Volterra to Kuramoto

“…The most obvious utility of such an approach is where synchronous dynamics are the focus of investigation (e.g. Earn et al,1998;Blasius et al, 199;Liebhold et al, 2004 ), and may have practical implications for the management of fisheries (Kaemingk et al, 2018), the planning complex biological control systems in agroecosystems (Vandermeer et al, 2019), or conservation (Earn et al, 2000).…”

Temporal resource continuity increases predator abundance in a metapopulation model: insights for conservation and biocontrol

“…For example, the assemblage of plants, herbivores, and natural enemies in real agricultural landscapes is large, overlapping, and complex (Vandermeer et al 2019, Snyder 2019 (Dainese et al 2019, Chaplin-Kramer et al 2011).…”