|adult hatched from an nymph of Ixodes ricinus|
Ixodiphagus hookeri is a small wasp which has the typical morphology of a chalcid 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 and on the females the antennae have eleven segments and the antennae are club shaped while in males they have ten segments and are thread-like.
Ixodiphagus hookeri has a short flight period in the summer in Europe and the female normally oviposits an egg into the body of an unfed nymph of Ixodes ricinus, but has been recorded ovipositing in the adults Rhipicephalus sanguineus, the egg remains in diapause 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 can become melanised and its death. The bacteria Wolbachia 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 konobiont parasitoids in the tick for 28 to 70 days before emerging. In Europe Ixodes ricinus appears to be the preferred species and the marsh tick Dermacentor reticulatus is not used as a host. Different populations of I. hookeri around the world show different host preferences, complicating attempts to use this species as a biological control for ticks.
Ticks from the genera Ornithodoros, Amblyomma, Dermacentor, Haemaphysalis, Hyalomma, Ixodes and Rhipicephalus are recorded as having been infected by I. hookeri. Because of the potential importance of I. hookeri as a natural enemy of ticks, it has been extensively researched.
I. hookeri occurs worldwide (except Antarctica).
- "Ixodiphagus hookeri (Howard, 1908)". GBIF.org. Retrieved 29 May 2017.
- Plantard O; Bouju-Albert A; Malard M-A; et al. (2012). "Detection of Wolbachia in the tick Ixodes ricinus is due to the presence of the hymenoptera endoparasitoid Ixodiphagus hookeri". PLoS ONE. 7 (1): e30692. doi:10.1371/journal.pone.0030692.
- M. S. Quaraishi (1958). "Morphology of Two Chalcidoid Parasites of Ticks, Hunterellus hookeri Howard, 1908, and Ixodiphagus texanus Howard, 1907". The American Midland Naturalist. 59 (2): 489–504.
- J. Collatz; P. Selzer; A. Fuhrmann; et al. (2010). "A hidden beneficial: biology of the tick-wasp Ixodiphagus hookeri in Germany". Journal of Applied Entomology. 135 (5): 351–358. doi:10.1111/j.1439-0418.2010.01560.x.
- Renjie Hu; K. E. Hyland; J. H. Oliver (1998). "A review on the use of Ixodiphagus wasps (Hymenoptera: Encyrtidae) as natural enemies for the control of ticks (Acari: Ixodidae) (abstract)". Systematic and Applied Acarology. 3 (1): 19–28. doi:10.11158/saa.3.1.3.