Deadly Perfume

R e s e a r ch highlights

host response Draining of glandular contents prior to exposure to fungal spores significantly reduced the survival of Deadly perfume larvae, and the authors propose that fumigation of fungal spores by the Insects can succumb to infection perfumes that can kill pathogens perfume cloud might prevent spore after ingestion of pathogens or when before they have had a chance to infect, germination and reduce the chances the insect cuticle is breached by path- and have published their findings in of infection. Moreover, treating cul- ogenic fungi. Antimicrobial defences the Journal of Chemical Ecology. tured Bacillus thuringiensis serovar which can combat pathogens that Leaf-beetle larvae produce tenebrionis and B. thuringiensis have gained access to the haemo- glandular secretions that contain sali- serovar kurstaki with concentrations coel have been characterized in cylaldehyde, a metabolic by-product of salicylaldehyde either directly Drosophila melanogaster, and include that is derived from the catabolism of or as a volatile inhibited bacterial the production of reactive oxygen salicin and saligenin. Previous studies growth, and therefore the deadly species and antimicrobial peptides. revealed that salicylaldehyde was a perfume could kill bacterial and Juergen Gross and colleagues now potent antifungal and antibacterial fungal pathogens. report that beetle larvae secrete agent in vitro, but little was known Insects, which are the most about when it was released or which numerous animal group on the microorganisms it could kill. Larvae Earth, have evolved a swathe of of Phratora vitellinae were placed in effective defences against patho- glass vials and their headspace was gens. This new study reveals that analysed by gas chromatography, insect perfumes might have been which confirmed that the main conserved during evolution to not volatile component of the secretions only benefit the producer, by killing was salicylaldehyde. Glands can be competitor insects or altering the everted to dispense secretions during behaviour of predators, but also to predator attack, but close inspection disinfect the external insect micro- of the cuticle above the glandular environment and reduce the chances reservoir using scanning electron of disease. microscopy revealed furrow-shaped Susan Jones openings through which the larvae could continuously secrete volatile Original Research Paper Gross, J., Schumacher, K., Schmidtberg, H. & Vilcinskas, A. compounds. The larvae are therefore Protected by fumigants: beetle perfumes in permanently surrounded by a cloud antimicrobial defense. J. Chem. Ecol. 34, 179–188 of salicylaldehyde. (2008)