A coevolutionary framework based on temporal and spatial ecology of host-parasite interactions: A missing link in studies of brood parasitism

Abstract

Almería, Spain Abstract A central tenet of coevolutionary theory, including theory of the coevolutionary relationship between brood parasites and their hosts, is that temporal and spatial patterns may reveal important information about ecological and evolutionary dynamics. For instance, level of genetic structure of populations provides important information about the role of genetics and gene flow in determin-ing local patterns of selection on hosts due to parasitism (i.e., egg rejection) and on parasites due to selection by hosts (i.e., egg mimicry). Furthermore, abiotic (i.e., climatic conditions) and biotic (phe-notypic characteristics of animals) factors that also vary spatially may directly or indirectly affect populations of hosts and brood parasites and, therefore, their interaction. By reviewing the literature, we found considerable evidence for an effect of the spatially and temporally structured abiotic environment on the phenotype of both parasite and host eggs and the degree of mimicry. Moreover, we found examples suggesting that specific life history characteristics of hosts that vary geographically and/or temporally may affect the probability of initial colonization of a new host species and the direction and the speed of coevolution. We provide an exhaustive review of studies investigating temporal and spatial patterns of the interaction between brood parasites and their hosts. Such temporal and spatial trends in parasite and host traits are, together with genetic information on rejection and significant effects of gene flow, consistent with coevolutionary dynamics. However, gene flow and changes in the temporal and spatial patterns of abundance of both parasites and hosts may result in frequent cases of counter-intuitive relationships between the phenotype of the parasite and that of the host (i.e., poor or no mimicry), which may suggest limits to the degree of adaptation. We provide a list of scientific questions in need of further investigation, concluding that studies of brood parasites and their hosts may play a central role in testing the geographic theory of coevolution and several