The absence of myrcene in digger pine phloem and required oleoresin intake calculations indicate myrcene cannot serve as a precursor for ipsenol in male bark beetles. Five pine species are equally suitable hosts for the beetles in terms of adult survival, nuptial chamber construction, pheromone production, and attraction, with pheromone production independent of myrcene titer, suggesting males use other precursors and myrcene variation does not affect insect-plant coevolution. Rhizoglyphus robini secretes a novel highly conjugated monoterpenoid, robinal (3-oxo-4-isopropylidene-1-cyclohexene-1-carboxaldehyde), identified via GC, GC-MS, IR, UV, and NMR, which is unique to this mite among 15 astigmatid mites investigated, present in mite exudates but not in foodstuffs, and may be biosynthesized by cyclization of α-acaridial. Brassinosteroids, a new class of plant-growth regulators, were found to strongly promote mycelial growth of Psilocybe cubensis: synthetic 22S,23S-homobrassinolide at 10⁻² ppm caused mycelia to grow two to three times faster on 6% malt agar, representing the first report of brassinosteroid activity on fungi.