Temperature‐dependent, behavioural, and transcriptional variability of a tritrophic interaction consisting of bean, herbivorous mite, and predator

Abstract

Different organisms compensate for, and adapt to, environmental changes in different ways. In this way, environmental changes affect animal-plant interactions. In this study, we assessed the effect of temperature on a tritrophic system of the lima bean, the herbivorous spider mite Tetranychus urticae and the predatory mite Phytoseiulus persimilis. In this system, the plant defends itself against T. urticae by emitting volatiles that attract P. persimilis. Over 20-40 °C, the emission of volatiles by infested plants and the subsequent attraction of P. persimilis peaked at 30 °C, but the number of eggs laid by T. urticae adults and the number of eggs consumed by P. persimilis peaked at 35 °C. This indicates that the spider mites and predatory mites performed best at a higher temperature than that at which most volatile attractants were produced. Our data from transcriptome pyrosequencing of the mites found that P. persimilis up-regulated gene families for heat shock proteins (HSPs) and ubiquitin-associated proteins, whereas T. urticae did not. RNA interference-mediated gene suppression in P. persimilis revealed differences in temperature responses. Predation on T. urticae eggs by P. persimilis that had been fed PpHsp70-1 dsRNA was low at 35 °C but not at 25 °C when PpHsp70-1 expression was very high. Overall, our molecular and behavioural approaches revealed that the mode and tolerance of lima bean, T. urticae and P. persimilis are distinctly affected by temperature variability, thereby making their tritrophic interactions temperature dependent.

A road map for molecular ecology

“…Lodge et al 2012;Malek et al 2012;Orozco-terWengel et al 2012;Parchman et al 2012;Pompanon et al 2012;Tedersoo et al 2012), as well as new questions that have resulted from merging formally disparate disciplines (e.g. Kraaijeveld et al 2012;Nosil & Feder 2012;Ozawa et al 2012;Simms & Porter 2012).…”

Beyond insects: current status and achievements of RNA interference in mite pests and future perspectives

“…The risk assessment of non‐target effects, especially on beneficial species such as natural enemies, is crucial to apply this technology in an integrated pest management (IPM) program. Important natural enemies of spider mites, such as P. persimilis and M. occidentalis , have been found to be sensitive to oral RNAi . However, given the evolutionary distance between predatory mites and herbivore mites, we believe that sequence‐dependent unintended effects can be avoided, given the appropriate target gene design.…”

“…Important natural enemies of spider mites, such as P. persimilis and M. occidentalis, have been found to be sensitive to oral RNAi. [11][12][13]20 However, given the evolutionary distance between predatory mites and herbivore mites, we believe that sequence-dependent unintended effects can be avoided, given the appropriate target gene design. Evaluation of the specificity of RNAi silencing in mites and the potential for unintended effects on non-target organisms and investigation of whether bioinformatics could be a useful tool in risk assessment are necessary.…”

Different population densities and continuous feeding byOligonychus yothersi(McGregor) (Acari: Tetranychidae) affect the emissions of herbivore-induced plant volatiles on avocado (Persea americanaMill. cv. Hass) shoots under semi-field conditions

“…Likewise, high amounts of (E)-β-ocimene, α-farnesene, farnesyl cyanide and MeSA were collected from O. yothersi-infested avocado shoots(Table 1). The emission of farnesyl cyanide from mite-infested avocado plants constitutes the first report of the presence of this sesquiterpene in volatile profiles from mite-infested plants.Evidence indicates that temperatures and light are the main environmental factors controlling the dynamics of both BVOCs' and HIPVs' emissionsKigathi et al 2009; Staudt and Lhoutellier 2011) Ozawa et al (2012). found that lima bean (P. lunatus cv.…”