Parasitoid–host metapopulation dynamics: the causes and consequences of phenological asynchrony

Abstract

Summary1. The strength of interaction between the specialist parasitoid Cotesia melitaearum and the host butterfly Melitaea cinxia is influenced by the coincidence of the adult stage of the parasitoid with the larval stage of the host. 2. We show that there is great variation in this developmental synchrony among local populations and among years, ranging from complete synchrony to complete asynchrony. 3. The causal mechanism is early spring temperature, which affects parasitoid development differently than the development of the host. 4. At cool air temperatures the dark-coloured and mobile host larvae benefit from basking in the sun, while the white and immobile parasitoid cocoons develop slowly in shaded microclimates, becoming adults after hosts have pupated and are no longer available for parasitism. At warm temperatures many adult wasps emerge in time to parasitize host larvae. 5. We show that the host-parasitoid synchrony influences subsequent parasitoid population size and the rate of colonization of previously uninhabited host populations, contributing to parasitoid metapopulation dynamics. 6. We detected no direct effect of the phenological synchrony on local host population size, but the synchrony is likely to be important for overall host metapopulation dynamics via variation in the rate of colonization by the parasitoid.

Phenological asynchrony between herbivorous insects and their hosts: signal of climate change or pre-existing adaptive strategy?

“…By this means, the caterpillars can use cool, sunny conditions to generate adaptive phenological asynchrony with the parasitoids. In dull weather, they are not able to do this and suffer increased parasitoid attack as a result (Van Nouhuys & Lei 2004). In this situation, it seems clear that almost any change of climate would influence relative development time and, hence, the degree of butterfly-parasitoid synchrony, with consequences for the dynamics of their interaction.…”

Displacement of Aphytis chrysomphali by Aphytis melinus, parasitoids of the California red scale, in the Iberian Peninsula

“…Meta-analysis estimates an average displacement per decade of northern and altitudinal species distribution boundaries of 6.1 km and 6.1 m northward and upward respectively (Parmesan & Yohe, 2003). In addition to the more predictable effects of abiotic factors on single species, species idiosyncratic phenological responses to changes in environmental variables are expected to trigger a cascade of changes on species interactions at all ecological levels with unpredictable consequences (Davis et al, 1998;Chapin et al, 2000;Van Nouhuys & Lei, 2004). In the present work, a comprehensive study describing CRS parasitoid assemblages in the main Spanish citrus growing areas has been conducted.…”

Environmental Impacts—Terrestrial Ecosystems

“…Case studies documenting this process are rare. Van Nouhuys and Lei (2004) showed that warmer, early spring-temperatures favoured the parasitoid wasp Cotesia melitaearum disproportionally, bringing it into closer synchrony with its host the butterfly Melitaea cinxia. Although the authors found no direct effect of the phenological matching on local host population size, the synchrony is likely to be important for overall host meta-population dynamics via variation in the rate of colonisation by the parasitoid.…”