title: Larvae of the parasitoid wasp Ampulex compressa sanitize their host, the American cockroach, with a blend of antimicrobials.
abstract: Food resources contaminated with spoilage or pathogenic microorganisms pose severe problems to all higher organisms. Here, we describe a food-hygienic strategy of the emerald cockroach wasp Ampulex compressa. The wasp larvae develop on and inside the American cockroach Periplaneta americana, a host that can harbor various putrefactive microbes, as well as human and insect pathogens. From P. americana, we isolated the Gram-negative bacterium Serratia marcescens, which is a potent entomopathogen that can rapidly kill insect larvae. It is also known as a food contaminant and as an opportunistic human pathogen. Using behavioral observations and chemical analyses, we demonstrated that A. compressa larvae impregnate their cockroach hosts from inside with large amounts of an oral secretion containing a blend of γ-lactones and isocoumarins with (R)-(-)-mellein [(R)-(-)-3,4-diydro-8-hydroxy-3-methylisocoumarin] and micromolide [(4R,9Z)-octadec-9-en-4-olide] as dominant components. We fractionated hexane extracts of the secretion and investigated the antimicrobial properties of the fraction containing the lactones and isocoumarins, as well as of synthetic (R)-(-)-mellein and micromolide, against S. marcescens and a Gram-positive bacterium, Staphylococcus hyicus, in broth microdilution assays. The test fraction inhibited growth of both tested bacteria. The activity of the fraction against S. marcescens was explained by (R)-(-)-mellein alone, and the activity against S. hyicus was explained by the combined action of (R)-(-)-mellein and micromolide. Our data suggest that the specific combination of antimicrobials in the larval secretion provides an effective frontline defense against the unpredictable spectrum of microbes that A. compressa larvae may encounter during their development inside their cockroach hosts.
authors.affiliation: Evolutionary Ecology Group, Institute of Zoology, University of Regensburg, 93053 Regensburg, Germany. gudrun.herzner@biologie.uni-regensburg.de
authors.forename: Gudrun
authors.initials: G
authors.lastname: Herzner
authors.forename: Anja
authors.initials: A
authors.lastname: Schlecht
authors.forename: Veronika
authors.initials: V
authors.lastname: Dollhofer
authors.forename: Christopher
authors.initials: C
authors.lastname: Parzefall
authors.forename: Klaus
authors.initials: K
authors.lastname: Harrar
authors.forename: Andreas
authors.initials: A
authors.lastname: Kreuzer
authors.forename: Ludwig
authors.initials: L
authors.lastname: Pilsl
authors.forename: Joachim
authors.initials: J
authors.lastname: Ruther
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D005798:Genes, Bacterial; D006790:Host-Parasite Interactions / Q000502:physiology*; D006801:Humans; D049934:Isocoumarins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D007783:Lactones / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D008969:Molecular Sequence Data; D010526:Periplaneta / Q000382:microbiology* / Q000469:parasitology*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012706:Serratia marcescens / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D057788:Staphylococcus hyicus / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D014863:Wasps / Q000382:microbiology / Q000472:pathogenicity / Q000502:physiology*
chemical_list: D000890:Anti-Infective Agents; D049934:Isocoumarins; D007783:Lactones; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S