Parasitoid
The term "parasitoid" was coined in 1913 by the Swedo-Finnish writer Odo Reuter,[3] and adopted in English by his reviewer,[4] the entomologist William Morton Wheeler.
From this analysis, proposed by K. D. Lafferty and A. M. Kunis, the major evolutionary strategies of parasitism emerge, alongside predation.
Most ectoparasitoids are idiobiont, as the host could damage or dislodge the external parasitoid if allowed to move and moult.
Most endoparasitoids are koinobionts, giving them the advantage of a host that continues to grow larger and avoid predators.
[19] About 10% of described insects are parasitoids, in the orders Hymenoptera, Diptera, Coleoptera, Neuroptera, Lepidoptera, Strepsiptera, and Trichoptera.
The approximate number (estimates can vary widely) of parasitoid species[26] out of the total is shown in square brackets, e.g. [2,500 of 400,000].
The parasitoid wasps include some 25,000 Ichneumonoidea, 22,000 Chalcidoidea, 5,500 Vespoidea, 4,000 Platygastroidea, 3,000 Chrysidoidea, 2,300 Cynipoidea, and many smaller families.
[30][31][32] Hosts such as ants often behave as if aware of the wasps' presence, making violent movements to prevent oviposition.
[33] Parasitoid wasps face a range of obstacles to oviposition,[6] including behavioural, morphological, physiological and immunological defences of their hosts.
[36] Some parasitoid wasps locate hosts by detecting the chemicals that plants release to defend against insect herbivores.
In fact, populations across the southern U.S. were inexplicably closely related, considering rate of range expansion from a presumed Central American origin.
Responsive adult females overwhelmingly chose their familiar song, indicating the use of a learned, auditory search image.
Interestingly, when receptive females only heard silence the night before testing for preference, they chose the host songs equally, 50/50.
tympana tuned to host sound cues, larviparous) supports the extraordinarily fast range expansion of O. ochracea, as well as the presence and power of learning in parasitoids.
Natural enemies are more difficult to produce and to distribute than chemicals, as they have a shelf life of weeks at most; and they face a commercial obstacle, namely that they cannot be patented.
[62] Commercially, there are two types of rearing systems: short-term seasonal daily output with high production of parasitoids per day, and long-term year-round low daily output with a range in production of 4–1000 million female parasitoids per week, to meet demand for suitable biological control agents for different crops.
[63][64]Maria Sibylla Merian (1647–1717) was one of the first naturalists to study and depict parasitoids and their insect hosts in her closely-observed paintings.
[65] Parasitoids influenced the religious thinking of Charles Darwin,[e] who wrote in an 1860 letter to the American naturalist Asa Gray: "I cannot persuade myself that a beneficent and omnipotent God would have designedly created parasitic wasps with the express intention of their feeding within the living bodies of Caterpillars.
"[67] The palaeontologist Donald Prothero notes that religiously minded people of the Victorian era, including Darwin, were horrified by this instance of evident cruelty in nature, particularly noticeable in the ichneumonid wasps.
[68] Parasitoids have inspired science fiction authors and screenwriters to create terrifying parasitic alien species that kill their human hosts.
[72][73][74] The molecular biologist Alex Sercel, writing in Signal to Noise Magazine, compares "the biology of the [Alien] Xenomorphs to parasitoid wasps and nematomorph worms from Earth to illustrate how close to reality the biology of these aliens is and to discuss this exceptional instance of science inspiring artists".
He further compares the Xenomorph life cycle to that of the nematomorph Paragordius tricuspidatus which grows to fill its host's body cavity before bursting out and killing it.
[75] Alistair Dove, on the science website Deep Sea News, writes that there are multiple parallels with parasitoids, although in his view, there are more disturbing life cycles in real biology.
[76] The social anthropologist Marika Moisseeff argues that "The parasitical and swarming aspects of insect reproduction make these animals favoured villains in Hollywood science fiction.
