Genotype-specific interactions between parasitic arthropods

Abstract

Despite the ubiquity of coinfection, we know little of the effects of intra-specific genetic variability on coinfection by distinct parasite species. Here we test the hypothesis that parasite multiplication depends on the combination of parasite genotypes that coinfect the host (that is Genotype. × Genotype interaction). To that aim, we infected tomato leaves with the ecto-parasitic mites Tetranychus urticae and Tetranychus evansi. We tested all possible combinations between four T. urticae and two T. evansi populations sampled on different hosts or localities. There was no universal (that is genotype-independent) effect of coinfection on mite multiplication; in many cases the two species had no effect on each other. However, several combinations of T. evansi and T. urticae populations led to elevated T. evansi numbers. Similarly, T. urticae reproduction largely depended on the interaction between T. urticae and T. evansi populations. This evidence for genotype-by-genotype interaction between coinfecting parasites indicates that the effect of coinfection on parasite epidemiology and evolution may vary in space according to the genetic composition of local parasite populations; it further suggests the possibility of coevolution between parasites species that share the same hosts.

Identification of spider-mite species and their endosymbionts using multiplex PCR

“…Indeed, they are easily applicable, for instance, to estimate species prevalence while studying interspecific competition or performing an invasion experiment (e.g., Sarmento et al 2011;Sato et al 2014;Orsucci et al 2017), or to determine endosymbiont establishment and invasion in laboratory populations (e.g., Xi et al 2005). Moreover, the use of these multiplex PCR on non-extracted single individuals can be particularly useful for quick and costeffective prevalence assessment on field-collected populations.…”

Why Do Herbivorous Mites Suppress Plant Defenses?

“…This local hyper-suppression coincided with the increased expression of effector-encoding genes in T. evansi ( Te28 and Te84 ) and, moreover, was paralleled by an increased production of eggs by T. evansi -but not by the invading T. urticae ( Schimmel et al, 2017a ). Also Orsucci et al (2017) found evidence for an increase in T. evansi ’s reproductive performance when T. urticae was present on the same tomato leaf. In the opposite experimental situation, no significant changes were detected in the plant’s defense responses, nor did T. urticae females produce more eggs upon introduction of T. evansi to adjacent leaf tissue ( Schimmel et al, 2017a ).…”

Population‐level dynamics in experimental mixed infections: evidence for competitive exclusion among bacterial parasites of Paramecium caudatum

“…This may be surprising considering the large number of studies showing interactions between host and parasite genotypes, often with crossing reaction norms for infectivity and resistance related traits (Lambrechts et al 2005, de Roode and Altizer 2010), including for Paramecium-Holospora interactions (Adiba et al 2010, Duncan et al 2010, Fellous et al 2012, Bella et al 2016). Furthermore, both parasite and host genotype have been shown to change which parasite has higher fitness in a coinfection scenario (Louhi et al 2015, Klemme et al 2016, Orsucci et al 2016. Nevertheless, other studies show host genotype does not necessarily change the rank order of parasite fitness in coinfections, even when genotype impacts individual parasite traits (Susi et al 2015b).…”