Host plant manipulation of natural enemies: leaf domatia protect beneficial mites from insect predators

Abstract

Acarodomatia are small tufts of hair or invaginations in the leaf surface and are frequently inhabited by several taxa of non-plant-feeding mites. For many years, ecologists have hypothesized that these structures represent a mutualistic association between mites and plants where the mites benefit the plant by reducing densities of phytophagous arthropods and epiphytic microorganisms, and domatia benefit the mite by providing protection from stressful environmental conditions, other predaceous arthropods, or both. We tested these hypothesized benefits of domatia to domatia-inhabiting mites in laboratory and growth chamber experiments. In separate experiments we examined whether domatia on the wild grape, Vitis riparia, provided protection against drying humidity conditions or predaceous arthropods to two species of beneficial mite: the mycophagous species Orthotydeus lambi, and the predaceous species Amblyseius andersoni. For both taxa of beneficial mite, domatia significantly increased mite survivorship in the presence of the predatory bug, Orius insidiosus and the coccinellids Coccinella septempunctata and Harmonia varigata. There was no evidence for a protective effect of domatia with a third species of predatory arthropod, lacewing larvae Chrysoperla rufilabris. In contrast, there was no evidence for either species of beneficial mite that domatia provided any protection against low humidity. Thus in this system the primary mechanism by which domatia benefit beneficial mites is by protecting these organisms from other predatory arthropods on the leaf surface.

Influence of leaf trichomes on predatory mite (Typhlodromus pyri) abundance in grape varieties

“…Although initially controversial, evidence has accumulated in support of this hypothesis (Agrawal and Karban 1997;Norton et al 2000;English-Loeb et al 2005;Monks et al 2007). Trichomes may help moderate the eVects of low humidity (Grostal andO'Dowd 1994, but see Norton et al 2001), protect mites from predators (Roda et al 2000;Norton et al 2001;Faraji et al 2002;Seelmann et al 2007), and increase the capture of alternate food sources such as pollen and fungal spores that promote retention of generalist mite populations (Putman and Herne 1964;Kreiter et al 2002;Roda et al 2003). In a recent review, Romero and Benson (2005) suggest current evidence best supports protection from predators.…”

Domatia reduce larval cannibalism in predatory mites

“…It has been hypothesised that leaf domatia mediate mutualistic interactions between plants and predatory and fungivorous mites because they protect the mites against adverse conditions ( Pemberton & Turner, 1989;O'Dowd & Willson, 1991;Grostal & O'Dowd, 1994 ;Walter, 1996 ) and against other predators or omnivores ( Norton et al , 2001;Faraji et al , 2002a , b). Owing to this protection, the survival of predators on plants with domatia would be higher than on plants without domatia ( Agrawal & Karban, 1997;Agrawal et al , 2000;English-Loeb et al , 2002 ).…”

“…They are mainly inhabited by predatory and fungivorous mites and are therefore referred to as acarodomatia ( Pemberton & Turner, 1989;O'Dowd & Pemberton, 1998 ). A mutualistic interaction between plants and the mites through leaf domatia has been hypothesised, with the mites being protected inside the domatia ( Norton et al , 2001;Faraji et al , 2002a ). This would result in increased survival of the mites, resulting in an increased consumption of herbivores or plant-pathogenic fungi, thereby providing benefit to the plant ( O'Dowd & Willson, 1991;Walter & O'Dowd, 1992;Grostal & O'Dowd, 1994 ;Walter, 1996 ).…”

“…Thus far, it is clear that domatia can protect the mites against adverse abiotic conditions such as drought ( Walter & O'Dowd, 1992;Grostal & O'Dowd, 1994) , intra-guild predation ( Norton et al , 2001 ) and counterattacking prey ( Faraji et al , 2002a ), but not whether they also offer protection against cannibalism. Cannibalism is a common ecological interaction in nature ( Polis, 1981;Elgar & Crespi, 1992 ), and occurs frequently in predatory mites ( Croft & Croft, 1996;Schausberger, 2003;Montserrat et al , 2006 ).…”

Revealing the role of predator interference in a predator–prey system with disease in prey population

“…The strength of interference among predators is habitat specific. Habitat structures can change encounters between predators (Norton et al, 2001) and may therefore alter interference among predators (Grabowski and Powers, 2004). As a result, changes in habitat may lead to different outcomes in response to introduction of predator to control disease.…”