The coevolution of host resistance and parasitoid virulence

Abstract

Host-parasitoid interactions are abundant in nature and offer great scope for the study of coevolution. A particularly fertile area is the interaction between internal feeding parasitoids and their hosts. Hosts have evolved a variety of means of combating parasitoids, in particular cellular encapsulation, while parasitoids have evolved a wide range of countermeasures. Studies of the evolution of host resistance and parasitoid virulence are reviewed, with an emphasis on work involving Drosophila and its parasitoids. Genetic variation in both traits has been demonstrated using isofemale line and artificial selection techniques. Recent studies have investigated the fitness costs of maintaining the ability to resist parasitoids, the comparative fitness of flies that have successfully defended themselves against parasitoids, and the degree to which resistance and virulence act against one or more species of host or parasitoid. A number of studies have examined geographical patterns, and sought to look for local adaptation; or have compared the traits across a range of species. Finally, the physiological and genetic basis of change in resistance and virulence is being investigated. While concentrating on Drosophila, the limited amount of work on different systems is reviewed, and other possible areas of coevolution in host-parasitoid interactions are briefly discussed.

Abundance and host associations of parasitoids attacking frugivorous drosophilids on Iriomote-jima, a subtropical island of Japan

“…Parasitoids in return evolve ways to cope with host defenses, such as sticky eggs, virus-like particles and venom virulence factors (Fleury et al, 2009). Both host resistance and parasitoid virulence are thought to be graded traits, which form clines and mosaics in natural communities, based on local selective forces (Boulétreau & Fouillet, 1982;Carton & Nappi, 1991;Kraaijeveld & van Alphen, 1994, 1995Kraaijeveld et al, 1998;Kraaijeveld & Godfray, 1999).…”

Genetic dimension of the coevolution of virulence–resistance in Drosophila – parasitoid wasp relationships

“…Insects infested with parasitoids initiate a haemocyte-mediated response (a melanotic capsule) that quickly destroys the intruders Nappi, 1997, 2001), but parasitoids have developed various passive or active mechanisms to counteract this immune response (Strand and Pech, 1995;Godfray 2000). The possibility that these systems may coevolve is a recurrent question in evolutionary ecology (Kraaijeveld et al, 1998;Kraaijeveld and Godfray, 1999). Thompson (1999) has proposed that the selective interactions between species commonly differ between populations, resulting in coevolutionary 'hot spots' and 'cold spots'.…”

Evaluating the Costs of Mosquito Resistance to Malaria Parasites

“…These trade-offs result in optimal resource allocation, thereby holding the evolution of resistance in check (Sheldon and Verhulst 1996). The assumptions inherent in this hypothesis are that disease resistance is heritable, prevalence and intensity of infection in host populations are highly variable, resources are finite, resource allocation to reproductive or somatic function is plastic, and resistance is indeed costly.Using a variety of invertebrate intermediate host or vector/parasite systems, it has proved possible to rapidly select for parasite resistance within the laboratory context (Huff 1929;Thompson and Sikorowski 1979;Al-Mashhadani et al 1980;Collins et al 1986;Feldmann and Ponnudurai 1989;Thathy et al 1994;Kraaijeveld et al 1998;Somboon et al 1999;Webster and Woolhouse 1999;Mucklow and Ebert 2003) thereby upholding the first assumption concerning the heritable nature of many resistance traits.The plasticity of resource partitioning is demonstrated by the inverse relationship between reproductive effort or other costly activities, and resource allocation to immune function (Konig and Schmid-Hempel 1995;Sheldon and Verhulst 1996;Siva-Jothy et al 1998;McKean and Nunney 2001;Rolff and Siva-Jothy 2002;). Additionally, when immune systems are experimentally stimulated, trade-offs occur between immune stimulation and longevity (Moret and Schmid-Hempel 2000) or reproduction (Ahmed et al 2002;Schwartz and Koella 2004).…”

“…Using a variety of invertebrate intermediate host or vector/parasite systems, it has proved possible to rapidly select for parasite resistance within the laboratory context (Huff 1929;Thompson and Sikorowski 1979;Al-Mashhadani et al 1980;Collins et al 1986;Feldmann and Ponnudurai 1989;Thathy et al 1994;Kraaijeveld et al 1998;Somboon et al 1999;Webster and Woolhouse 1999;Mucklow and Ebert 2003) thereby upholding the first assumption concerning the heritable nature of many resistance traits.…”