A new strain QHLA of Lecanicillium uredinophilum was isolated from a Chinese caterpillar fungus complex and its optimum growth temperature and fermentation conditions were studied. Its insecticidal activity was tested against larvae of seven different insect pests, including Henosepilachna vigintioctopunctata, Spodoptera exigua, Plutella xylostella, Spodoptera frugiperda, Sitobion avenae, Hyalopterus perikonus, and Aphis citricola. The optimum growth temperature was 21–24 °C. The highest spore production of the strain QHLA was 4.08 × 106 spore/mL on solid medium with a nitrogen source of NH4Cl. However, the highest mycelial growth rate of the strain QHLA was on solid medium with a nitrogen source from yeast extract (4.63 ± 0.03 mm/d). When the liquid medium contained peptone, yeast extract, and glucose, the water content of the mycelia was the lowest, while the spore production was the highest until day 12. When the liquid medium contained glucose, tussah pupa powder, KH2PO4, and MgSO4, the mycelia production was highest until day 8. The bioassay for insecticidal activity indicated that the LC50 values of QHLA were 6.32 × 103 spore/mL and 6.35 × 103 spore/mL against Sitobion avenae and Aphis citricola, respectively, while the LC90 values of the strain QHLA against Aphis citricola and Sitobion avenae were 2.11 × 107 spore/mL and 2.36 × 108 spore/mL, respectively. Our results demonstrated that the strain QHLA was a high virulence pathogenic fungus against insect pests, with the potential to be developed as a microbial pesticide.

Historically, some edible insects have been processed into a complex of insect and fungus, such as Antherea pernyi and Samsoniella hepiali. Until now, the dynamics of the nutritional changes due to this infection were unclear. This study reveals the dynamic changes in nutritional components of Antherea pernyi pupa after infection with Samsoniella hepiali at post-infection time points of 0 d, 10 d, 20 d, and 30 d. The dynamic analysis of the components at different post-infection times showed that the content of polysaccharides and cordycepin increased with time while the content of fats and chitin decreased. The content of proteins showed a trend of decreasing at the beginning and then increasing. The essential amino acids (EAAs) decreased at the beginning and then increased, and non-essential amino acids (NEAA) changed similarly. The essential amino acid index showed a slight continuous decrease. Although the crude fat decreased dramatically due to the infection, from a value of 30.75% to 7.2%, the infection of S. hepiali produced five new fatty acids (14-methyl-pentadecanoic acid, docosanoic acid, succinic acid, arachidonic acid, and myristic acid) while the content of the seven fatty acids was greatly reduced after infection. Therefore, after being infected by S. hepiali and combined with it, the nutritional profile of A pernyi pupa was changed significantly and there were different characteristics at different infection stages. The above findings provide scientifically fundamental data to understand the nutritional value of the insect–fungus complex as human food and animal feed.