Antimicrobial defense in the emerald cockroach wasp Ampulex compressa (Hymenoptera, Ampulicidae)


The Emerald cockroach wasp (or Juwelwasp) Ampulex compressa is a solitary parasitoid wasp that belongs to the family Ampulicidae. Soon after eclosion and mating female A. compressa start to hunt cockroaches like the American cockroach Periplaneta americana. Once a female has traced a cockroach, it attacks it and bites its pronotum. It first stings into the thorax to cause a transient paralysis of the forelegs. Next, the A. compressa  female injects venom into the cerebral ganglia to transfer the cockroach into a lethargic state. The docile host cockroach is then dragged to a small cavity that serves as a nesting site. There, the female attaches one egg to a mesothoracic leg of the cockroach. Subsequently the female closes the nest with twigs and stones and virtually immures the cockroach.


Two to three days after oviposition the larva hatches. It first remains at the oviposition site on the outer cuticle of the cockroach and sucks hemolymph through a hole in the cockroach cuticle. After about six to seven days it migrates inside the cockroach and feeds on the inner tissues, which eventually causes the death of the host. After eroding the cockroach almost completely, the larva forms a cocoon inside the empty cockroach shell in which pupation and metamorphosis take place. About 5-6 weeks after oviposition the new adult wasp emerges from the cockroach and the cycle begins anew.


Due to their unsanitary life-style cockroaches may harbor different kinds of microorganisms, including saprophytic as well as entomopathogenic bacteria and fungi that compete for the food source or may infect the A. compressa larvae. As the cockroach host represents both, the only food source and the “cradle” of the wasp immature, the latter have to deploy effective defense strategies to keep such competing and pathogenic microorganisms at bay.


We could show that larvae of A. compressa impregnate their hosts from inside with large amounts of an antimicrobial secretion. This secretion comprises a blend of at least nine different chemical compounds, with (R)-(-)-mellein and micromolide being the most prominent components. Together, the different components of the larval secretion show broad-spectrum activity against a wide range of different microbes such as bacteria, mycobacteria, fungi and a virus. The ecological role of the secretion is thus the protection of the food of A. compressa larvae from competing microbes as well as the protection of the larvae themselves from pathogens during the time of development inside the cockroach.

 



 


Publications

Herzner G (2014) Antimicrobial defense strategies in two solitary wasp species. Entomolgie heute 26: 1-17.

Weiss K, Parzefall C, Herzner G (2014) Multifaceted Defense against Antagonistic Microbes in Developing Offspring of the Parasitoid Wasp Ampulex compressa (Hymenoptera, Ampulicidae). PLoS ONE 9(6): e98784. doi:10.1371/journal.pone.0098784.

Herzner G (2014) Wie schützen sich Larven der Juwelwespe vor schädlichen Mikroben? BIOSpektrum 20(2): 142-143.

Herzner G, Schlecht A, Dollhofer V, Parzefall C, Harrar K, Kreuzer A, Pilsl L, Ruther J (2013) Larvae of the parasitoid wasp Ampulex compressa sanitize their host, the American cockroach, with a blend of antimicrobials. Proceedings of the National Academy of Sciences of the USA 110 (4): 1369-1374.

 





Fotos © Gudrun Herzner


 
updated:
08.08.2015