Response of the predatory mite Phytoseiulus macropilis (Banks) to volatiles produced by strawberry plants in response to attack by Tetranychid mites (Acari: Phytoseiidae: Tetranychidae)

Abstract

-The attack of phytophagous mites may induce plants to produce volatiles, which in turn may attract predators. The occurrence of multiple phytophagous infestations on plants may infl uence predator response. In this paper, we investigated whether the attraction of the predatory mite Phytoseiulus macropilis (Banks) to phytophagous-infested plants would change with the simultaneous presence of two tetranichid mites Oligonychus ilicis (McGregor) and Tetranychus urticae Koch. While the former species is rarely found on strawberry plants and is only occasionally found in association with P. macropilis, the latter is commonly found on strawberry plants and is frequently found in association with P. macropilis. Y-tube olfactometer test assays demonstrated that the predator preferred plants infested with T. urticae, avoided plants infested with O. ilicis, and had no preference for plants infested with both phytophagous mite species. These results indicated that the presence of a non-prey species (O. ilicis) on a given plant can alter the response of the predator to one of its prey (T. urticae). The consequences of the predatory behavior determined in this study on the predator ability to control T. urticae population on strawberry plants are discussed. KEY WORDS: Induced defense, Fragaria, Tetranychus urticae, Oligonychus ilicisThe attack of phytophagous mites to plants may induce the production of plant volatiles, which in turn may attract natural enemies (Dicke et al 1998, Arimura et al 2005.The role of such herbivore-induced plant volatiles (HIPV) on predator attraction has been studied under laboratory (Pallini et al 1997, Takabayashi et al 2000, greenhouse (Janssen 1999, Venzon et al 1999, Holtz et al 2003 and fi eld conditions (De Moraes et al 1998, Drukker et al 2000, Kessler & Baldwin 2001, Heil & Kost 2006. The complexity of these studies increases with the experimental scale. Under natural conditions, for instance, the presence of more than one species of herbivore on the same plant may alter the blend of HIPV and thereby interfere with the response of natural enemies (Vos et al 2001, Shiojiri et al 2002, Moayeri et al 2007.Few studies have investigated the effects of multiple herbivore infestations on natural enemy attraction. Shiojiri et al (2002) found that the parasitoid Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) prefers odours of cabbage plants infested with its host Plutella xylostella (L.) (Lepidoptera: Plutellidae) alone, to cabbage plants infested with its host and a non-host herbivore species, Pieris rapae (L.) (Lepidoptera: Pieridae). In contrast, parasitism by Cotesia glomerata (L.) (Hymenoptera: Braconidae) was higher on plants infested with these two herbivores than on plants infested with P. rapae (host) alone.Moayeri et al (2007) observed a stronger attraction of the predator Macrolophus caliginosus Wagner (Heteroptera: Miridae) when plants were infested by spider mites and aphids than when plants were infested by only one of these herbivores. They suggested that the attrac...

Direct defense elicited by Tetranychus urticae koch (Acari: Tetranychidae) in Bt maize plants

“…The number of dead adult females was higher in pre-infested plants than in the clean plants ( Figure 1D, χ 2 =10.9, df=58, P<0.001). As demonstrated in the first part of the present investigation and in previous investigations SCHMELZ, 1996;FADINI et al, 2010a;PAULO et al, 2017), the pre-infestation of non-Bt maize plants by T. urticae reduced the survival and reproduction of the conspecific adult females, and it also reduces the survival of immatures. This suggests that maize plants which have undergone pre-infested by T. urticae altered the survival pattern of conspecific adult forms, reducing the performance of the population as a result of direct defense induction.…”

Olfactory response of Sancassania polyphyllae (Acari: Acaridae) to its phoretic host larva killed by the entomopathogenic nematode, Steinernema glaseri (Rhabditida: Steinernematidae)

“…Predatory mites are known to use volatiles to find their hosts (Janssen et al, 1997). For example, Y-tube olfactometer test assays demonstrated that predatory mites including Phytoseiulus persimilis (Athias and Henriot), Typhlodromus kerkirae (Swirski and Ragusa), Amblyseius womersleyi (Schicha), Phytoseiulus macropilis (Banks) have responded to volatiles from spider mites infested plants (Sabelis and van de Baan, 1983;Koveos and Broufas, 1999;Maeda et al, 2001;Fadini et al, 2010). Only one Y-tube study (Skelton et al, 2007) has been conducted using acarid mite, Tyrophagus putrescentiae (Schrank), which has contributed to the difficulties in designing appropriate bioassays.…”

Alien interference: disruption of infochemical networks by invasive insect herbivores

“…A recent study on the attraction of predatory mites Phytoseiulus macropilis (Banks) illustrates how an uncommon herbivore can interfere with a chemically mediated tritrophic interaction (Fadini et al . ). It was found that the predator was strongly attracted to plants with spider mites Tetranychus urticae , but avoided the odour of plants infested with red mites Oligonychus ilicis .…”

“…Doubly infested plants, carrying both herbivores, were not attractive to the predator, which supports the notion that interference in the chemical signalling by the unfamiliar herbivore may occur in this system (Fadini et al . ).…”