E. nostras genome assembly. Euroleon nostras genome

Neuropteran larvae are fierce predators that use venom to attack and feed on arthropod prey, but the ecology and evolution of venom deployment in different neuropteran families is poorly understood. We used spatial transcriptomics, proteomics, morphological analysis and bioassays to investigate the venom system in the antlion Euroleon nostras and the lacewing Chrysoperla carnea. Although the general morphology of the venom system was similar in both species, we found substantial differences at the molecular level. E. nostras produces particularly complex venom that is secreted from three different glands, indicating functional compartmentalization. E. nostras venom and digestive tissues were devoid of bacteria, providing strong evidence that all venom compounds are of insect origin rather than the products of bacterial symbionts as previously suggested. We identified several toxins that were exclusive to the venom of E. nostras, including phospholipase A2 and several undescribed proteins with no homologs in the C. carnea genome. The compositional differences have significant ecological implications, as only antlion venom had potent insecticidal activity, indicating its use for the rapid immobilization of large prey. Our results emphasize the importance of molecular venom evolution as an adaptive mechanism to distinct ecological niches.