Host Plant-Induced Changes in Detoxification Enzymes and Susceptibility to Pesticides in the Twospotted Spider Mite (Acari: Tetranychidae)

Abstract

Adult female twospotted spider mites, Tetranychus urticae Koch, reared on lima bean plants were moved to cucumber, maize, or new lima bean plants (the latter being a control) and evaluated after 24 h or 7 d for changes in susceptibility to three pesticides and in levels of related detoxification enzymes. The largest and most consistent changes were observed in mites feeding on cucumber. Susceptibility of mites on cucumber to the synthetic pyrethroids bifenthrin and lambda-cyhalothrin was greater than that of mites reared on lima bean and maize after only 24 h on the plants, and remained higher after 7 d. Mites on cucumber also were more susceptible to the organophosphate dimethoate than were mites on lima bean, but only after 7 d on the host. Susceptibility was inversely related to activities of both general esterase and glutathione S-transferase (GST) in mites on cucumber; general esterase and GST activities were 60 and 25% lower, respectively, than activities of twospotted spider mite on lima bean after 7 d of feeding. Mites on maize were slightly but significantly more susceptible than those on lima bean to bifenthrin, but not to lambda-cyhalothrin, after 7 d and to dimethoate after 24 h but not after 7 d. General esterase and GST activities in twospotted spider mite fed on maize for 24 h were 20 and 16% higher, respectively, than activities in twospotted spider mite on lima bean, but general esterase activity was 30% lower than lima bean-fed mites and GST was not different after 7 d. Thus, plant-induced changes in general esterase activity, perhaps in combination with GST activity, in twospotted spider mite appear to be inversely related to, and possibly responsible for, changes in susceptibility of twospotted spider mite to several pesticides, particularly the synthetic pyrethroids. General esterases appear to play less of a role in the detoxification of the organophosphate insecticide dimethoate.

A link between host plant adaptation and pesticide resistance in the polyphagous spider miteTetranychus urticae

“…Host plants are also known to affect the toxicity of insecticides to insects (13-16, 18-23, 25). Feeding on alternative hosts changes the activity of mite detoxification enzymes measured with some model substrates (24,73), and performance of mites on tomato was negatively affected by a P450 inhibitor (92). These findings indicate that the transcriptomic changes we observed may be essential for perfor-mance.…”

“…We show here that adaptation to tomato not only changes the transcript levels of many detoxification enzymes, but also results in a decreased acute toxicity for three of five acaricides tested. The transcriptional remodeling we observed after adaptation to tomato may thus be the proximal cause for the well-known effect of host plants on the efficacy of acaricides in T. urticae (17,24,90,91). Host plants are also known to affect the toxicity of insecticides to insects (13-16, 18-23, 25).…”

“…The "preadaptation hypothesis" for insecticide resistance has been supported by surveys of the literature (11,12) although the comparisons drawn between herbivores and natural enemies or between chewing and sucking herbivores may be confounded by taxonomy, thus calling for other forms of experimental and observational evidence (12). It is now well accepted that herbivore exposure to different plant allelochemicals can affect the toxicity of pesticides (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Moreover, metabolic resistance to pesticides is known to commonly rely on the increased expression of one or more genes encoding detoxification enzymes and formal evidence that many of these detoxification enzymes can metabolize both plant chemicals and pesticides is accumulating (26,27).…”

Tri-Trophic Level Impact of Host Plant Linamarin and Lotaustralin on Tetranychus urticae and Its Predator Phytoseiulus persimilis

“…Agrawal et al (2002) and Magowski et al (2003) reported that host plant preference by the two-spotted spider mite was influenced by the presence of natural toxins, and these impacted mite reproductive performance. Negative response to those chemicals can be overcome by conditioning, i.e., increasing acceptability of the host plants to subsequent spider mite generations (Navajas, 1998;Yang et al, 2001). Host plants also induce physiological changes in the mites by activating detoxification enzymes such as general esterases and glutathione S-transferases; this affects the susceptibility of the mites to some pesticides.…”

Identification of potential detoxification enzyme genes in Leptinotarsa decemlineata (Say) and study of their expression in insects reared on different plants

“…The link between enzyme activities and insect detoxification abilities is well documented. Insect susceptibilities to insecticides often vary depending on host plant, suggesting that insect detoxification ability can be modulated by allelochemicals in host plants (Feyereisen 1999;Yang et al 2001;Riley and Tan 2003;Tilquin et al 2004). …”