Host-Range Evolution: Adaptation and Trade-Offs in Fitness of Mites on Alternative Hosts

Abstract

Trade‐offs in fitness on different host plants has been a central hypothesis in explaining the evolutionary specialization of herbivores. Surprisingly, only a few studies have documented such trade‐offs. In this paper, I present results from a selection experiment that demonstrates trade‐offs in host plant use for a polyphagous spider mite. Although adaptation to a novel poor‐quality host did not result in detectable costs on a favorable host, spider mites that had adapted to a poor‐quality host lost their ability to tolerate the poor‐quality host when they were reverted to the favorable host for several generations. Trade‐offs in fitness on alternative hosts among herbivorous spider mites remains one of the classic empirical examples of constraints on the evolution of host range. Adaptation to the novel poor‐quality host was not associated with adaptation to a related host‐plant species or to particular host‐plant chemicals that I assayed. Thus, the complexity of host‐plant defenses may restrict host shifts to single species of novel host plants, and adaptive zone shifts onto entire groups of plants predicted by the Ehrlich and Raven Model may be rare. Spider mite performance was genetically associated with host‐plant preference. Mites from the control population showed a significant preference for the favorable host plant, whereas mites adapted to the novel host plant showed no preference. Finally, although induced plant responses to herbivory in the poor‐quality host decreased the fitness of unselected mites, induced responses resulted in higher fitness of adapted mites. These results suggest that spider mites that rapidly adapt to particular host plants can overcome constitutive and inducible plant defenses.

Effect of soybean cultivar on life history parameters of Tetranychus urticae Koch (Acari: Tetranychidae)

“…Several researchers have demonstrated that spider mites produce differently populations on various plant cultivars such as Tetranychus truncatus Ehara on corn (Pang et al 2005); Amphitetranychus viennensis and T. urticae on apple (Kasap 2003;Skorupska 2004, respectively), and T. urticae on ivy geranium (Opit et al 2001) on strawberry (Gimenez Ferrer et al 1993;Suzanne and Hutchison 2003) on cucumber (Park and Lee 2007) and on soybean (Wheatley and Boethel 1992). Several potential mechanisms could be responsible of observed differences, including plant nutritional quality of the host plant and morphological or allelochemical features (Sabelis 1985;Krips et al 1998;Dike et al 1999;Agrawal 2000;Pietrosiuk et al 2003;Balkema-Boomstra et al 2003). Host plant species and cultivars often differ in chemical profiles, thereby affecting herbivore physiology (Ode 2006), and interactions between various organisms (Stout et al 2006).…”

Is the Cereal Rust Mite, Abacarus Hystrix Really a Generalist? – Testing Colonization Performance on Novel Hosts

“…Such observations are numerous for tetranychid mites (e.g. Fry 1989Fry , 1999Gotoh et al 1993;Yano et al 1998;Agrawal 2000;Egas and Sabelis 2001), and comparatively scarce for eriophyoid mites. This may be due to the rearing problems and to the relatively low economic relevance compared to tetranychid mites.…”

Cooperative web sharing against predators promotes group living in spider mites

“…After another 24 h, I counted the cumulative egg numbers laid and calculated egg numbers laid by each test female by subtracting the egg number of the initial female from the cumulative number. Because the number of eggs laid within a certain period is considered the most sensitive performance index of spider mite females (Yano et al 1998;Gotoh et al 1999;Agrawal 2000;Yano et al 2003), any indirect interaction, either exploitative competition or plant mediated interaction, between females sharing webs should result in lower (or higher) egg numbers laid by the test female. A one-way ANOVA (SAS Institute Inc. 1998) was performed on the data for each test female species.…”