''Ixodiphagus hookeri'', the tick wasp, is an encyrtid wasp which lays its eggs into

ticks Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...

. It seems to use a symbiotic

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

, ''

Wolbachia pipientis ''Wolbachia'' is a genus of intracellular bacteria that infects mainly arthropod species, including a high proportion of insects, and also some nematodes. It is one of the most common parasitic microbes, and is possibly the most common repr ...

'', to weaken the tick's

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as Tumor immunology, cancer cells and objects such ...

Description

''Ixodiphagus hookeri'' is a small wasp which has the typical morphology of an encyrtid wasp and is blackish in colour, it measures 0.8-0.9mm in length and has a wing length span of 1.5mm. Its head is dorsally flattened with very large compound eyes. In females, the antennae have eleven segments and the antennae are club shaped; while in males they have ten segments and are thread-like.

Biology

''Ixodiphagus hookeri'' has a short flight period in the summer in Europe. The female normally oviposits an egg into the body of an unfed

nymph A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ty ...

of ''

Ixodes ricinus ''Ixodes ricinus'', the castor bean tick, is a chiefly European species of hard-bodied tick. It may reach a length of when engorged with a blood meal, and can transmit both bacterial and viral pathogens such as the causative agents of Lyme dis ...

'', but has been recorded ovipositing in the adults of ''

Rhipicephalus sanguineus ''Rhipicephalus sanguineus'', commonly called the brown dog tick, kennel tick, or pantropical dog tick, is a species of tick found worldwide, but more commonly in warmer climates. This species is unusual among ticks in that its entire lifecycle ...

''. The egg remains in

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press It ...

until the nymph engorges on vertebrate blood, at which point the egg becomes active. Some eggs are not successful, as the tick's immune system can encapsulate the egg, which results in the egg becoming melanised and dying. The bacteria ''

Wolbachia ''Wolbachia'' is a genus of intracellular bacteria that infects mainly arthropod species, including a high proportion of insects, and also some nematodes. It is one of the most common parasitic microbes, and is possibly the most common repro ...

'' is symbiotic with the wasp, and its presence in ticks is a possible indicator of infestation by tick wasps; ''Wolbachia'' may have a role in suppressing the host's immune system response to the wasp. The wasp larvae then exist as koinobiont parasitoids in the tick for 28 to 70 days before emerging. Ticks from the genera ''

Ornithodoros ''Ornithodoros'' is a genus in the soft-bodied tick family, Argasidae. Physiology The opening between the midgut and hindgut has been lost, making the ticks unable to pass digestive waste products out of their bodies. Taxonomy The Linnean name ...

'', ''

Amblyomma ''Amblyomma'' is a genus of hard ticks. Some are disease vectors, for example the Rocky Mountain spotted fever in Brazil or ehrlichiosis in the United States. This genus is the third largest in the family Ixodidae, with its species primarily oc ...

'', ''

Dermacentor ''Dermacentor'' is a genus of ticks in the family Ixodidae, the hard ticks. The genus has a cosmopolitan distribution, with native species on all continents except Australia. Most occur in the Nearctic realm. Hosts of ''Dermacentor'' ticks i ...

'', ''

Haemaphysalis ''Haemaphysalis'' is a genus of ticks, containing these species: *''Haemaphysalis aborensis'' Warburton, 1913 *''Haemaphysalis aciculifer'' Warburton, 1913 *''Haemaphysalis aculeata'' Lavarra, 1904 *''Haemaphysalis adleri'' Feldman-Muhsam, 1951 ...

'', ''

Hyalomma ''Hyalomma'' is a genus of hard-bodied ticks common in Asia, Europe, and North Africa. They are also found in Southern Africa. The name is derived from Greek: hyalos (ὕαλος) crystal, glass; and omma (oμμα) eye. The genus is believed to ...

'', ''

Ixodes ''Ixodes'' is a genus of hard-bodied ticks (family Ixodidae). It includes important disease vectors of animals and humans ( tick-borne disease), and some species (notably '' Ixodes holocyclus'') inject toxins that can cause paralysis. So ...

'' and ''

Rhipicephalus ''Rhipicephalus'' is a genus of tick Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". ...

'' are recorded as having been infected by ''I. hookeri''. In Europe, ''Ixodes ricinus'' appears to be the preferred species and the marsh tick ''

Dermacentor reticulatus ''Dermacentor reticulatus'', also known as the ornate cow tick, ornate dog tick, meadow tick, and marsh tick, is a species of tick from the family Ixodidae. It is the type species for the genus '' Dermacentor''. ''D. reticulatus'' is an ornate t ...

'' is not used as a host. Because of the potential importance of ''I. hookeri'' as a natural enemy of ticks, it has been extensively researched. Different populations of ''I. hookeri'' around the world show different host preferences, complicating attempts to use this species as a

biological control Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically als ...

for ticks. Ixodiphagus hookeri

Distribution

''I. hookeri'' occurs worldwide, except in

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest co ...

References

External links

''I. hookeri'' at the Universal Chalcidoidea Database
{{Taxonbar, from=Q309554 Encyrtinae Hymenoptera of Europe Hymenoptera of North America Insects described in 1908