This study examined two types of parasitic fungi (Cordyceps javanica and Cordyceps blackwelliae) that infect insects, comparing how they kill their hosts and what chemical compounds they produce during infection. Researchers found that each species uses different toxic molecules to infect insects, with C. javanica being more deadly and producing diverse compounds called beauveriolides. By analyzing infected insect corpses, scientists provided the first direct evidence that these toxic compounds are actually made during real infections, not just in laboratory cultures.