The influence of genetic variation on pre‐oviposition processes for host‐parasitoid co‐evolution

Despite the importance of parasitoid wasps as biological control agents and the vast literature available on different aspects of their natural history and ecology, it is only recently that an interest in integrating genetics into aphid‐parasitoid studies has emerged. Some studies have been completed on the effect of genetic variation on aphid parasitism outcomes, especially after the description of aphid physiological resistance to parasitoids and its role in their co‐evolution. The interaction between aphids and parasitoids goes beyond the physiological conflict between the parasitoid egg and the aphid internal defences. A series of aphid and parasitoid attributes, that can be influenced by biotic and abiotic factors, precedes that last step in the oviposition process. The understanding of how genetic variation can play a crucial role in influencing the pre‐egg‐laying stages of the aphid‐parasitoid interaction remains relatively unexplored. Here, we review currently available information on this topic. We contextualise the aphid‐parasitoid co‐evolution process exemplified by the post‐oviposition approach. Knowledge gaps are also discussed and the significance of fulfilling them is addressed. An ecology‐evolutionary perspective on aphid‐parasitoid research is advocated, by incorporating genetic variation into the study of aphid‐parasitoid co‐evolution. This will increase the understanding of the adaptation and evolution of both organism's characteristics in response to each other and abiotic pressures, and also the implications for pest management. Co‐evolution between aphid hosts and their parasitoids has been associated with adaptative pressures linked with aphid physiological resistance (related to aphid and their endosymbionts' genetic variation) and parasitoid virulence. The aphid‐parasitoid interaction is composed of multiple previous stages before parasitoid oviposition that has been relatively unexplored as source of variability for parasitism outcomes. Genetic variation associated with aphids and parasitoids' attributes involved in those early stages of the interaction has been unconsidered on both basic and applied biology research.