Hyperparasitic wasps help fight ticks
Ticks transmit a wide range of microorganisms causing serious infections in humans and animals. It is estimated that there are more than 1400 human-pathogenic species of vector-borne bacteria, viruses and parasites worldwide. At least 60% of them are zoonotic species, i.e. transmissible from animals to humans.
"In connection with the epidemiological significance of these blood-sucking ectoparasites, there is an increasing need for an effective fight against ticks. Until now, the most frequently used strategy has been the application of chemical acaricides. However, due to the increasing resistance of ticks to these substances and their toxicity and negative impact on the environment, it is necessary to look for alternative solutions, such as plant extracts or essential oils. Ticks also have various natural enemies, such as some species of birds, bacteria pathogenic for insects, entomophagous fungi, helminths and parasitoids of the genus Ixodiphagus," says Veronika Blažeková from the Institute of Parasitology SAS.
Ixodiphagus hookeri is a parasitoid wasp that attacks various species of soft (family Argasidae) and hard (family Ixodidae) ticks, including those found in our conditions (genera Ixodes, Haemaphysalis and Dermacentor).
"The wasp lays its eggs in the bodies of tick nymphs, while the wasp larvae feed on the internal tissue of the host and the sucked blood in the body of the tick. The adults bite their way out of the body of the attacked nymph, killing their host. This process prevents the reproduction of parasitized ticks, which makes I. hookeri a suitable candidate for biological control of ticks," explains the parasitologist.
Research has shown that parasitoid wasps from the genus Ixodiphagus can participate in the regulation of the occurrence and abundance of tick populations and can also influence to some extent the dynamics of diseases caused by tick-borne microorganisms. Parasitized ticks die before the start of their reproduction, which also regulates the transstadial and transovarial transfer of pathogenic agents.
"We established laboratory breeding of I. hookeri wasps using sterile ("pathogens-free") ticks, which creates space for their further practical use. In laboratory conditions, we achieved an increase in the rate of parasitism of ticks by wasps by almost 50% more than they occur in nature. In the near future, we plan to release sterile ticks infested with wasps in locations with a high incidence of ticks and pathogens, which may contribute to the regulation of the population of these blood-sucking arthropods," ads the scientist.
The project represents a significant step in the fight against ticks and their vectors, using environmentally friendly methods that have the potential to improve public health and animal protection.
Edited by Monika Tináková
Foto: Parazitologický ústav SAV, v. v. i.