These results suggest that the four isolates with gradient descent efficacies also had gradient descent capacities against desiccation, and MAX-2 had significantly higher antistress capacity under desiccation stress than the other isolates. MAX-2 caused similar symptoms to other isolates in the wet microhabitat

NSC 683864 nmr (substrate with 35% moisture content; Figure 3a). T. molitor larvae exhibited bradykinesia, and the internodes of insects turned slightly brown in the early stage of infection (2 d to 3 d post-inoculation; Figure 3b). The internodes gradually became dark black, and the larvae died within the following 2 d (Figure 3c). White mycelia sprang up and gradually covered the cadavers approximately 10 d after inoculation. The conidia formed, and the larval surface turned green after another 1 d to 2 d (Figure 3d). The substrate also showed white mycelia, which gradually turned light green during the course of infection. This phenomenon suggests that

new conidia formed and added to the initial inoculum concentration, thereby resulting in a large number of inocula around the larvae (Figure 3e). Figure 3 The symptoms of T. molitor larvae infected by M. anisopliae isolate MAX-2. Note: a-e, in the wet microhabitat; f-j, GSK458 under desiccation stress. Bar = 1 cm (a-j). The arrows in g, h, and i indicated the local black patches on the cuticles under desiccation stress. In the dry microhabitat (substrate with 8% moisture content; Figure 3f), MAX-2 exhibited medium efficacy (41% mortality), whereas the other isolates showed no efficacies or very low efficacies (< 5% mortality). Similar to the observations in the wet microhabitat, T. molitor larvae exhibited bradykinesia in the dry microhabitat, but the larvae exhibited local black patches on the cuticles 3 d to 4 d after inoculation (Figure 3g). The local black patches gradually extended to one to two somites, and the

larvae became slower, died, and dried (Figure 3h). LY294002 mouse However, no mycelium or conidia emerged on the insect cadavers and substrates when kept in dry substrate all the time. This result suggests that the moisture level Thiamine-diphosphate kinase was too low to facilitate mycelial or conidial growth. However, when the cadavers were transferred to a moist filter, mycelium and conidia rapidly emerged on their surface within 2 d to 3 d (Figure 3j). In addition, few larvae completed exuviation and survived even when local black patches appeared on the shell (Figure 3i). Discussion A valid laboratory bioassay system for evaluating M. anisopliae efficacy under desiccation stress Water stress tolerance of fungal strains is usually evaluated using various salts to create different water potential scenarios. However, in testing the virulence of the strains, the salt can affect the life cycles of hosts. In this paper, a novel laboratory bioassay system was used to test the efficacy of M. anisopliae under desiccation stress on T. molitor larvae in dry substrate.