Nitric oxide radicals are emitted by wasp eggs to kill mold fungi

Detrimental microbes caused the evolution of a great diversity of antimicrobial defenses in plants and animals. Insects developing underground seem particularly threatened. Here we show that the eggs of a solitary digger wasp, the European beewolf Philanthus triangulum, emit large amounts of gaseous nitric oxide (NO⋅) to protect themselves and their provisions, paralyzed honeybees, against mold fungi. We provide evidence that a NO-synthase (NOS) is involved in the generation of the extraordinary concentrations of nitrogen radicals in brood cells (~1500 ppm NO⋅ and its oxidation product NO2⋅). Sequencing of the beewolf NOS gene revealed no conspicuous differences to related species. However, due to alternative splicing, the NOS-mRNA in beewolf eggs lacks an exon near the regulatory domain. This preventive external application of high doses of NO⋅ by wasp eggs represents an evolutionary key innovation that adds a remarkable novel facet to the array of functions of the important biological effector NO⋅.

Nitric oxide radicals are emitted by wasp eggs to kill mold fungi

Detrimental microbes caused the evolution of a great diversity of antimicrobial defenses in plants and animals. Here we show that the eggs of a solitary digger wasp, the European beewolf Philanthus triangulum, emit large amounts of the gaseous free radical nitric oxide (NO.) to protect themselves and their provisions, paralyzed honeybees, against mold fungi. Despite the extraordinary concentrations of nitrogen radicals (NO. and its oxidation product NO2.) in the brood cells (~1500ppm), NO. is synthesized from L-arginine by an NO-synthase (NOS) as in other animals. The beewolf NOS gene revealed no conspicuous differences to related species. However, due to alternative splicing, the NOS-mRNA in beewolf eggs lacks a 144bp exon near the regulatory domain. This preventive external application of high doses of NO. by seemingly defenseless wasp eggs represents an evolutionary key innovation that adds a remarkable novel facet to the array of functions of the important biological effector NO..

Morphology of the sting apparatus of the digger wasp Oxybelus uniglumis (Linnaeus, 1758) (Hymenoptera, Crabronidae), with emphasis on intraspecific variability and behavioural plasticity

The solitary digger wasp Oxybelus uniglumis (Linnaeus, 1758) uses its sting not only for paralyzing prey but also for transporting the prey to the nest site. The sting morphology is expected to reflect the mechanical overloading applied to the sting during prey transportation. In this paper, we provide a detailed description of the sting skeleton of Oxybelus uniglumis and define specific morphological characters in order to reveal possible morphological predictions for conducting specific prey-carriage behaviour. The most important features are the following: (1) In contrast to all other known Apoidea, Oxybelus uniglumis has a single (instead of double) valvillus; (2) There are no distinct borders between the rostral process and the 2nd valvula, so the valvula is relatively strongly articulated to the basal elements of the sting; (3) The internal skeleton exhibits intraspecific variation, which has not previously been recorded for Hymenoptera. Results are discussed from a functional standpoint.