The solitary parasitoid wasp lays her nut in the body of a caterpillar or standardised host . After it hatches , the developing larva dines on the cat ’s interior until eventually tearing its agency through the skin of the host , killing it . Since the parasitoid depend entirely on the cat for its maturation , the quality of the legion is quite important , and have an entire caterpillar to oneself is critical for offspring survival . allot to novel workplace published inPLOS ONEthis week , distaff wasps can tell if competing parasitoids have laid their eggs inside a host . They can even count how many ball are already there .
premature subject field on parasitoid behavior bring out that the tiny 2 - mm ( 0.08 - inch ) longLeptopilina heterotomauses its ovipositor – the acerate leaf - like bollock inject Hammond organ ( see above ) – to separate between unparasitized and parasitized fruit fly larva . The specie is also known to discriminate between hosts with different numbers of parasitoid eggs already inside them . This science require some experience , and how female choose the dependable potential host has remain a mystery .
AWageningen Universityteam led by Sara Ruschioni require to see if there was a receptive base for this so - called host discrimination . Using hemolymph ( a blood - corresponding vital fluid ) from fruit fly larva , the team energise tiny structures similar to smack buds – foretell sensilla – situate at the very tip of the ovipositor of the wasps . There are seven sensilla at end of an ovipositor , and each are innervate by six neuron .
The researchers made electrophysiological recording of nervous signals as they excite just one sensillum using hemolymph from unparasitized fruit fly larvae , from one - time - parasitized larva , and from those that had been parasitized twice already .
The neuronal response of sensillia to these hemolymph samples varied dramatically depending on both the presence and act of parasitoid eggs inside the host – suggest that innkeeper discrimination is encoded by taste receptor neurons at the ends of ovipositors . And activeness from just three of the six neuron will suffice .
