Multitrophic interactions of Helicoverpa moths with their hostplants and parasitoids
The feeding of the generalist H.armigera and the specialist H.assulta resulted in the same inductions of jasmonic acid, lipoxygenase, and proteinase inhibitors, but H. assulta caused the less intensive foliar polyphenol oxidase increase, more intensive nicotine and POD increases in tobacco than H. armigera.Upon exposure of intact maize seedlings to wound-induced GLVs, (Z)-3-hexenyl acetate and (E)-4,8-dimethyl-1,3,7-nonatriene was released in the neighboring plants, demonstrating that absorption, conversion and release of volatiles occurred for plant-plant communication.——Planta(226:215-224) Phytochemistry(67:34-42) Journal of Experimental Biology (213:2889-2895), Journal of Insect Physiology(55: 788-792)
“Interspecific facilitation”,“symbiotic invasion”and “back invasion” hypotheses
About 25 years ago, the red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Scolytinae), was accidentally introduced into China, where it attacks several pines, particularly Chinese pine (Pinus tabuliformis Carrière) (Sun et al. 2013). We performed a comparative study of fungal associates of RTB in its native and introduced regions in order to elucidate the possible role of symbiotic fungi in beetle behavioral shift (Lu et al. 2009). Both the fungus and beetle therefore appear to benefit each other from this association. The symbiotic relationship between D. valens and its phoretic fungi, Leptographium spp., especially the two most commonly isolated strains of L. procerum in China, is probably mutualistic since the fungi can benefit from these symbioses to be translocated to new host trees, and beetles can take the benefits of fungi to help overcome tree defenses (Lu et al. 2010, 2011). In addition, laboratory studies showed that the RTB larvae fed with the two Chinese isolates of L. procerum acquired significantly more weight than those larvae fed with other isolates (Wang et al. 2013). ——PLoS ONE (12:1-9) New Phytologist(187:859-866) Ecology(92:2013-2019) Annual Review of Entomology 58: 293-311
PWN-vector beetle-associated fungi interactions mediated by infochemicals
Pine wilt disease (PWD) is perhaps the most serious threat to pine forests worldwide. The causative agent of PWD, the pinewood nematode (PWN), engages in a symbiotic partnership with its insect vector, the Monochamus beetle, as well as associated bacteria and ophiostomatoid fungi, in order to successfully infect and kill its host pine tree (Zhao et al. 2014). Specific fungal isolates (Sporothrix sp. 1) induce the xylem tissue of the pine tree to produce diacetone alcohol (DAA), which may also increase PWN propagation and beetle larvae growth(Zhao et al. 2013). As conditions deteriorate inside the pine tree, PWN enters the dispersal phase of its life cycle (JⅢ and JⅣ). Then JⅢ moult to JⅣ in response to C16 and C18 FAEEs released from the surface of the emerging Monochamus beetle adult. Additional chemical or other types of signals may stimulate association of JIV with the beetle adult for dispersal to a new pine tree host.——Ecology 94: 2817-2826 Current Biology 23: 2038-2043
