Ananichneumon Wasp Orthopelma mediator
A member of the Ichneumonidae family this wasp is the main parasite of the Cynipidae wasp Diplolepis rosae. Other species targeted include D. spinosissimae, D. mayri and D. eglanteriae. It is an endoparasite and as such deposits its eggs directly into the larvae of its host before the bedeguar gall has begun development, thereby making all the larvae available, as opposed to just the outer ones of the already formed gall. Being an early stage parasite it may well then open itself for hyperparasitization at a later date by Eurytoma rosae, Pteromalus bedeguaris and Torymus bedeguaris.
The female wasp is long and slender in shape. Head and body measurements are 2.4-5mm, averaging to 4mm. The wasp has a black head and thorax, with large black eyes and ocelli. It has long, slender, dark antennae that consist of 21 segments. The coxae are black, as is the hind femora, while the rest of the legs, including the trochantor, are brown with pale joints, although sometimes the rear leg may be darker or grey in colour. The gaster (abdomen) is testaceous with yellow beneath and brown markings on the side and top with a short ovipositor.
The male wasp, like the female, is long and slender in shape although slightly bigger, measuring 2.7-5.5mm with an average of 4.6mm. It has a black head and thorax, with large black eyes and ocelli. It has long, slender, dark antennae that consist of only 20 segments. The coxae are black, as is the hind femora, while the rest of the legs, including the trochantor, are brown with pale joints, although sometimes the rear leg may be darker or grey in colour. The gaster (abdomen) is testaceous with yellow beneath and brown markings on the side and top.
As an internal parasite the wasp gives no indication of its presence until it is full grown, at the end of september, by which time it will have absorbed the entire contents of its host, excepting mouthparts. At this point the skin of the host is dull and ill fitting of the new wasp larva until after only a few days the host skin is shed and the O. mediator larva is revealed.
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The larva shape is of even thickness and bluntly rounded at both ends and slightly curved. The body surface is glabrous and shining, and the segmental divisions are not deeply incised. It has a lateral beeding along the side of the abdomen. by the end of october the larva has started to change and develops a waist as the thoracic segments become more compact and the first 2 abdominal ones become slender. The eyes also start to form on the second segment. These changes progress through the winter and are very pronounced by april, when the larva begins to pupate.
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After pupation the adult wasps tend to emerge at the end of april through to early june which corresponds with the emergance of the remaining Diplolepis wasps and surprisingly along with the Pteromalus bedeguaris wasps as well.
Polysphinta tuberosa
Polysphinctini (20 species in the British Isles) are parasitic on spiders, both young Polysphincta tuberosa (Ichneumonidae: Pimplinae) is unusual in being a koinobiont ectoparasitoid - allowing the host to continue development but living outside the host's body. The adult lays a single egg on the front of a spider's abdomen - the host is often the common white & yellow/green spider Araniella cucurbitina. The position of the egg makes it impossible for the spider to remove it using its legs or mandibles and makes rubbing it off very difficult. When the egg hatches the larva stays in the same position and pierces the host's skin to drink its body fluids. In its first weeks the larva remains quite small (c. 2mm) but this is because it is ticking over, waiting for the host to get big enough. Once it senses the host is the right size it will suck the spider dry over night and grow to 5-6mm in length! The larva then spins a silk cocoon and pupates - the adult hatching after a couple of weeks.
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info from chrisraper.org.uk
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Polysphinctini (20 species in the British Isles) are parasitic on spiders, both young and old.
Many young Polysphinctini overwinter as larvae on the young spider host or in the hosts
nest.
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Most Polysphincta and other genera of spider parasitoids place the egg dorsally or
laterally at the base of the spider abdomen, the host is temporarily paralyzed and the
firmly fixed eggshell is utilized by the developing larva as a means of maintaining its
attachment to the host body.
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There are approximately 11 species in this genus.: P. atavina · P. boops · P. dizardi ·
P. gutfreundi · P. longa · P. mascoi · P. nielseni · P. purcelli · P. rufipes ·
P. tuberosa · P. vexator
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