No abstract

How the non-consumptive effects (NCEs) of predators influence the development, survival, fecundity, and population growth of prey has not been well documented, which is the primary consideration for the compatibility of prey with its natural enemies in agricultural ecosystems. We herein employed the age-stage, two-sex life table to examine the NCEs of the predator Coccinella septempunctata on the life-history traits and population growth of prey Sitobion miscanthi via caged predator (prey co-existing with caged predator) and caged prey (predator co-existing with caged prey) treatments with daily different exposure times (i.e., 0 h (control), 12 h, and 24 h). The results indicated that the predation risk of a caged predator could reduce the first nymphal duration and net reproductive rate (R0) of S. miscanthi at 12 h, and the first nymphal duration, preadult duration, and mean generation time (T) at 24 h. However, the predation risk of the caged prey resulted in the prolongation of the pre-adult development time and total pre-reproductive period (TPRP) as well as lowered the intrinsic rate of increase (r), finite rate of increase (𝜆), R0, life expectancy, and reproductive value of S. miscanthi after both 12 h and 24 h. Furthermore, the predation risk of both the caged predator and caged prey could increase the percent of winged morph at 24 h. These findings indicate that S. miscanthi could respond to the predation risk of the caged predator by either accelerating the developmental rate or reducing the net reproductive rate, while S. miscanthi might reduce their fitness in response to the predation risk of caged prey. Furthermore, S. miscanthi might also alter to winged morphs for dispersal under both of the above treatments. The findings obtained have practical ramifications for managing this economically important pest in wheat production with reduced insecticide applications.

Evolution of the spread strategies of plant pathogens may be described using the vector manipulation hypothesis (VMH), which posits that pathogens can enhance their transmission to new host plants through their effects on mobile vectors. Barley yellow dwarf virus (BYDV) transmitted by aphid vectors in wheat has become increasingly important as a model pathosystem. However, the role of alate aphids in virus spread has attracted little attention although the migratory morph is a key vector for the long-distance dispersal of plant pathogens. Herein, we first examined the selection preferences of alate or aptera morphs of the vector Schizaphis graminum for healthy/mock-inoculated/BYDV-infected wheat plants and then identified possible volatile components that influenced alate S. graminum selection behavior. The results showed that noninfective S. graminum (either alate or aptera) mainly tended to select BYDV-infected wheat while infective S. graminum (only aptera) preferentially selected noninfected wheat. In addition, we found that the BYDV-infected plants showed significant differences in the content and quantity of volatiles compared with healthy or mock-inoculated wheat plants and that the increased volatiles (trans-2-hexen-1-al or decanal) released by BYDV-infected plants may play a critical role in attracting noninfective alate aphids in a concentration-dependent manner. These findings describe a novel mechanism by which the volatile profiles released by virus-infected plants may influence alate aphid colonization preference, providing further or new evidences for the VMH. This study extends our knowledge base on plant virus transmission to new host plants with potential ramifications for the integrated management of both the vector and disease.

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The development of efficient and cost-effective bifunctional electrocatalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is promising for high-performance rechargeable metal-air batteries. In this work, a Co-N,O-C@C3N4...