Genera Ichneumonorum Nearcticae
The purpose of the Genera Ichneumonorum Nearcticae is to present concise current information about the taxonomy, biology, distribution and species-richness of North American Ichneumonidae. Every effort has been made to ensure that the information presented is exhaustively referenced for accuracy. In the subsidiary sections (listed on the side-bar) our aim is to provide an introduction to each subfamily present in the Nearctic region, together with a concise subfamilial diagnosis and a synopsis of its biology. Each section is completed by keys to Nearctic genera, with each key augmented by high quality photographs, a summary of species present and reference to the current keys to species. The classification presented here is widely accepted by the international community, and although there will be inevitably some difference of interpretation, we present the most generally accepted current overview. We welcome comments on the Genera Ichneumonorum Nearcticae, and suggestions for its improvement.
General Introduction to the Ichneumonidae
The Ichneumonidae is the largest family of all the parasitic wasps, and worldwide it probably includes more than 100,000 species (Gauld, 2002), of which 23,500 are currently described and classified into 38 subfamilies (Table I). This remarkable diversity makes the Ichneumonidae one of the largest families of organisms on Earth, one that far exceeds, in terms of species-richness, all the vertebrate animals combined. Ichneumonids are common and conspicuous in all New World terrestrial biomes, from the desolate Arctic tundra, through the lush equatorial rainforests, to the windswept sub-Antarctic islands. They are found in suburban gardens and pristine forests, in deserts and on waterside vegetation. Although they are abundant in almost every habitat, unlike most other organisms they may reach their overall peak of species-richness in north temperate mixed woodland rather than in lowland tropical forest (Janzen, 1981).
Numerous ichneumonid species may be observed in most localities, such as fast-moving, brightly patterned ichneumonines that are most conspicuous on account of their vibrating white-banded antennae, cryptines with strikingly patterned wings flitting lazily along sun-dappled forest paths, menacing metallic blue Thyreodon with bright yellow antennae that fly robustly through the undergrowth, mimicking aggressive pompilid wasps, and the slender, orange-brown night-flying ophionines that cluster around bright lights at night. Many ichneumonids can be seen on flowers while feeding on nectar or pollen, but most often they are only glimpsed as they fly erratically through the understorey vegetation. A few ichneumonids are physically quite large, with long ovipositors that may exceed 60 mm in length. These ichneumonids excite attention wherever they occur, especially when they are found congregating around tree trunks in old-growth forests. Most ichneumonids, however, are rather dark-colored and inconspicuous.
All North American ichneumonids are parasitoids: they develop by feeding as a larva on a single immature host insect which is eventually killed by the ichneumonid. The adult ichneumonid is free-living. Males may be found in aggregations around sites where females are emerging, but females spend much of their time searching for prospective hosts on or into which they deposit an egg. Thus in many species there is pronounced sexual color-pattern difference, with the more conspicuous males aposematically banded with black and yellow, and the females cryptically brownish (Gauld & Fitton, 1987).
Ichneumonids attack a wide range of hosts, most frequently the larvae and pupae of the larger holometabolous insect orders (Lepidoptera, Diptera, Coleoptera or other Hymenoptera), although a very few also attack the immatures of other holometabolous insects such as Trichoptera (Agriotypinae), Mecoptera (a few Campopleginae), and Neuroptera (Brachycyrtinae, some Cryptinae). None are known to attack hemimetabolous insects (i.e. those with an egg/nymph/adult life cycle), although some feed on arthropod eggs in sacs, and a very few attack spiders. Most typically, the adult female ichneumonid lays an egg inside a host caterpillar, and the ichneumonid larva feeds selectively within its host, avoiding damage to the host caterpillar which continues to feed and grow like a normal larva. When the caterpillar is almost fully-grown, the ichneumonid larva consumes its insides entirely and breaks free from the caterpillar skin as a large whitish grub, which subsequently spins a cocoon under or next to the host larval remains. There is tremendous biological diversity within the Ichneumonidae: some drill through two or more centimeters of hardwood to find wood-boring grubs, some lay eggs inside an insect embryo in an egg, others drill into hard exposed pupae, and some temporarily paralyze and parasitize spiders (Eberhard, 2000). Some, such as Apsilops spp. (Cryptinae), search for hosts on plants growing in standing water. Agriotypus spp. (Agriotypinae) enter freshwater to search for the submerged pupae of caddis-flies (Elliott, 1982) and a few species of Cremastinae, such as Tanychela spp., enter freshwater to locate their nymphuline hosts (Resh & Jamieson, 1988).
The family Ichneumonidae is a clearly definable monophyletic group (Sharkey & Wahl, 1992) that includes the Hybrizontinae (= Paxylommatinae of authors) and the Agriotypinae. Because they are both highly autapomorphic, these latter two groups have often been treated as distinct families (e.g., by Mason, 1981), or in the case of the former, as a subfamily of Braconidae (e.g., by Achterberg, 1976). Gauld (1984: pp. 11-12) presents a cogent argument for including the Hybrizontinae within the Ichneumonidae. Currently the majority of authors follow the interpretation of Sharkey & Wahl (1992).
The internal classification of the Ichneumonidae has been subject to a great deal of change since the 19th century when only five subfamilies were recognized: Ichneumoninae, Cryptinae, Tryphoninae, Pimplinae and Ophioninae. As more natural groupings were recognized, the number of subfamilies steadily increased to 25 in Henry Townes' monographs on the genera (1969; 1970a&b, 1971). Subsequently, with the application of rigorous phylogenetic argumentation, particularly with regards to the Labeninae, Pimplinae and the Microleptinae [link in prep.] (sensu Townes), the number increased to 37 in a recent overview (Gauld, 2002). Four new subfamilies have been proposed in the last 15 years:
-Townesioninae: this subfamily, comprising Townesion and Sachtlebenia, was described from the eastern Palaearctic region by Kasparyan (1993) and placed near the Tryphoninae. Subsequently Gauld & Wahl (2000) demonstrated that this was a highly autapomorphic genus-group of Glyptini, and included it within this tribe in the Banchinae.
-Pedunculinae, Claseinae: Porter (1998) erected these two new subfamilies for aberrant and problematical endemic Neantarctic taxa, the Pedunculinae for Pedunculus, and the Claseinae for Clasis and Ecphysis. Gauld & Ward (2000) redefined the Pedunculinae to include endemic Australian genera previously placed in the Brachycyrtinae (Gauld, 1984), but saw no reason to resurrect the Claseinae from the Cryptinae.
-Nesomesochorinae: Townes (1970b) placed the Palaeotropical genus Chriodes and the Neotropical genus Nonnus together as the Nonnini, a tribe he placed with some reservations in the Campopleginae. Fitton & Gauld (1976) established the correct name of the tribe as Nesomesochorini. Miah & Bhuyia (2001) elevated this tribe to subfamilial status, and we agree that recognition of Nesomesochorinae is warranted because the group shares no unique derived features with campoplegines. The subsequent break-up of the Nesomesochorinae into two subfamilies by Quicke et al. (2005) is unwarranted as the three component genera, Chriodes, Klutiana and Nonnus share many morphological synapomorphies.
Currently we recognize 38 subfamilies (Table I) and this is perhaps the most generally recognized classification used at present, although some doubts remain about the status of a few taxa such as Skiapus and Clasis.
The history of ichneumonid classification is complicated further by nomenclatural confusion resulting from a variety of causes. Whilst this is not exceptional for many insect groups, a complicating factor in the Ichneumonidae arises from the fact that Henry Townes (the most influential ichneumonologist of the past century) used a rather idiosyncratic system of nomenclature, which was followed by many of his students and collaborators. It is only in the past decade that a system of nomenclature based on the International Code of Zoological Nomenclature (vide Fitton & Gauld, 1976; 1978; Wahl & Mason, 1995) has gained wide acceptance. For clarification, the Townes’ names of various taxa are given in Table I and a list is provided of all family-group names in Ichneumonidae.
We have avoided arranging the subfamilies in any informal groupings, although three natural groupings - the Pimpliformes, Ichneumoniformes and Ophioniformes - seem to be reasonably well supported by sound derived morphological features, despite continuing debate on their exact limits (Gauld, 1985; Wahl, 1991, 1993; Wahl & Gauld, 1998; Gauld & Wahl, 2000; Quicke et al., 2000).
New keys to the subfamilies present in North America are included in a separate section (in preparation) and details of each subfamily are given under the appropriate heading on the sidebar. Throughout both of these accounts standardized morphological terminology has been used. Details of this morphological terminology are given in the General Morphology section.
Catalogues of the described species of Ichneumonidae are: World (Yu & Horstmann, 1997); Nearctic (Carlson, 1979); Neotropic (Townes & Townes, 1966); Indo-Australian (Gupta, 1987); Ethiopian (Townes & Townes, 1973). Details of the size, distribution, characterization, composition, and biology of the various subfamilies are given below under subfamiliar headings
A Detailed Overview of Ichneumonid Biology
a. Life history: eggs.
b. Life history: larval and pupal stages.
Most koinobionts kill their host as a final instar larva within the host's pupation chamber and are thus afforded some degree of protection during their own pupation. Even so, many ichneumonids spin an ovoid, dense, silken cocoon (Slovák, 1984). Although considerable variation in the amino acid composition of silk has been found between various parasitoid taxa (Quicke & Shaw, 2004) all, except Adelognathus, were dominated by short side-chain amino acids. Which amino acid was dominant varied between taxa, but most silks could be interpreted as fibroins. Some ichneumonids that spend a very short period in their cocoon spin a quite frail cocoon. Multivoltine species may have cocoon dimorphism, with diapausing larvae spinning a thicker cocoon than their non-diapausing siblings (Danthanarayana et al., 1977; Fitton et al., 1982). The cryptine vespid parasitoid Sphecophaga has three forms of cocoons: a white form that gives rise to a brachypterous female; a thin yellow cocoon giving rise to winged females in the same summer; a thick yellow cocoon that gives rise to winged males and females the following summer (Donovan, 1991). The cocoons of some ichneumonids that undergo protracted diapause (e.g. Enicospilus lobophagus) are very dense and have a nacreous inner wall that is probably resistant to desiccation and penetration by micro-organisms. Ichneumonids that pupate within their host's pupa (such as Anomaloninae, Ichneumoninae, Metopiinae and Pimplini) generally do not make a cocoon or spin only a rudimentary cocoon, as do many idiobionts (such as Rhyssinae) that attack hosts deeply concealed in woody tissue. Many species seem to diapause as a prepupa, although a few north temperate species diapause as pharate adults within the cocoon (Morley, 1915).
Some campoplegines (e.g. Cryptophion spp.) are unusual in that they kill their host caterpillar on the food-plant before the caterpillar has become fully grown (Gauld & Janzen, 1994). In such an exposed situation, the ichneumonid cocoon is extremely vulnerable to scavengers or hyperparasitoids and various campoplegines have adopted a variety of strategies for concealing their cocoons from predators. Many species have black and white mottled cocoons that resemble bird-droppings. Those of Cryptophion are concealed under the host larval remains, whilst some northern temperate species of Hyposoter construct a false cocoon (Finlayson, 1966). Other species ensure that their cocoons are removed from the leaf surface. Those of Charops, for example, are suspended from the host food-plant by a long thread, and species of Bathyplectes and some Phobocampe have 'jumping cocoons' that break free of the substrate so that cocoon and pupa fall amongst the leaf litter (Gauld & Bolton, 1988).
c. Adult biology.
The great majority of ichneumonids are bisexual, and like other Hymenoptera arrhenotokous with fertilized diploid eggs producing females and unfertilized haploid eggs giving rise to males. However, a few cosmopolitan synanthropic ichneumonids (e.g., Diplazon laetatorius, Venturia canescens) are thelytokous throughout much of their range. Sphecophaga appears to have a deuterotokous form which exploits locally abundant resources, as well as normal bisexual forms that overwinter (Donovan, 1991). Sexual dimorphism is generally not as pronounced amongst the Ichneumonidae as it is in many other groups of apocritan Hymenoptera, although in a few genera it can be very striking. For example, some species of Cryptinae (e.g. many Gelis spp.) have apterous, ant-like females and normal alate males (Salt, 1952). Sexual dimorphism is most apparent in idiobiont groups, the males of which are relatively short-lived flower-feeders who spend most of their lives flying low through, or resting on the vegetation. The females, on the other hand, are long-lived and spend most of their lives on the ground searching for hosts in leaf litter or in concealment under bark etc. Thus some ichneumonine males are often aculeate mimics and aposematically colored, whilst the females are cryptic black or brownish insects. Many idiobionts (e.g., many Cryptinae, Pimplinae, and Labeninae) show considerable sexual dimorphism in size, a result of facultative arrhenotoky (Flanders, 1956; Aubert, 1959). Females lay a disproportionately large number of female (fertilized) eggs on large hosts and male (unfertilized) eggs on small hosts (Arthur & Wylie, 1959; Kishi, 1970). In general, koinobionts show less pronounced sexual dimorphism; males and females frequently resemble each other closely in shape, color pattern and even size (Gauld & Fitton, 1987) and both males and females can often be seen flying amongst or resting on the vegetation. The nocturnally active koinobionts are the least sexually dimorphic of all the ichneumonids, females and males generally differing only in the density of pectination of the tarsal claws (Gauld, 1988a).
The males emerge from the pupa before the females in many ichneumonid species. In the Rhyssinae (and probably also other wood-borer parasitoids), males may congregate around tree trunks from which conspecific females are in the process of emerging, with some of these males establishing territories which they defend against other males (Eggleton, 1990). Other species show scramble competition for mates and in these cases males are sometimes exceptionally elongate – a specialization for mating with the female prior to her full emergence (Nuttall. 1973). In temperate regions, males of some Orthocentrinae. Tersilochinae and Diplazontinae form conspicuous mating(?) swarms. Gauld (1991) observed that males of Joppidium (Cryptinae) form groups flying above and around newly emerged females. Such behavior suggests that the female may be releasing a pheromone, as has also been suggested for some Campopleginae (Vinson, 1972; Gordh & Hendrickson, 1976). Further evidence for sexual pheromones in Ichneumonidae is the observation that males of Exetastes cinctipes (Banchinae) are attracted to 8-dodecenyl and 11-tetradecenyl acetates (Hrdy & Sedivy, 1979).
Mating is rather brief (usually from one to ten minutes in duration) and has rarely been observed. The females of many species are believed to mate only once (Gordh & Hendrickson, 1976; Slovák, 1986) but some mate repeatedly (Mathur, 1967). The male often approaches the female from the rear and repeatedly strokes her with his antennae (Slobodchikoff, 1973; Barrows, 1976), but some species approach face to face with the male vibrating his wings (Veen, 1982). During copulation the male may be situated behind, above, or rarely to the side of the female. and he usually continues to antennate her throughout copulation (Barrows, 1976; Gordh & Hendrickson, 1976; Danthanarayana et al., 1977).
Little is known about the phenology of ichneumonids. In regions that have a pronounced winter or dry season, the majority of koinobiont species are active in spring or shortly after the start of the rains, exploiting the first flush of phytophagous larvae that appear when plants put on new growth. Most of these ichneumonids will have diapaused as prepupae in their host's pupal retreat. Many show a high degree of synchrony with their hosts and emerge as adults for a very short period. Sometimes, as in the case of Enicospilus lebophagus, only part of a year's population emerges the following year; a small proportion may remain in diapause for another twelve months (D.H. Janzen. pers. comm.).
Idiobionts, which mostly attack prepupae or pupae, tend to appear slightly later in the season. In the temperate region most do not survive the winter, but in the seasonal tropics many continue to fly about well into the following dry season. Thus in the seasonal tropics, unlike the northern temperate regions, idiobiont parasitoids may be active throughout the entire inclement season. Potential hosts that are in diapause are thus susceptible to attack throughout their diapause (Gauld, 1987). A few species of genera such as Camera (Cryptinae) and Clistopyga (Pimplinae) have only been collected in the dry season, suggesting they may diapause in the wetter periods. In the northern temperate regions, some species, particularly of the Ichneumoninae, diapause as adults, concealing themselves during the winter beneath the bark of trees and in grass tussocks (Rasnitsyn, 1964).
Ichneumonids have a variety of defensive strategies against predators. Some are furnished with cuticular processes. which may offer physical protection. For example. some species of Certonotus (Labeninae) have spines on the pronotum, propodeum and metanotum, and Acrotaphus species (Pimplinae) have a pronotal shield and occipital flange protecting the cervical membrane against attacks by asilids. Many medium-sized to large species of tropical mesostenines are black and white striped, an adaptation that renders them very difficult to focus on (at least for the human eye) as they fly through patches of light and shade in the forest understory. Species of the pimpline genera Theronia and Xanthopimpla have large tarsal claws with an internal poison-sac, these claws functioning as a poison fang (Townes, 1940). Most of these species are also aposematically colored and, like those capable of stinging, many are Müllerian mimics of aggressive aculeates (Gauld, 1991). Many other species are also brightly colored and are apparently Batesian mimics of aculeates (Evans, 1966, 1968). Some (e.g. Dolichomitus spp.) are yellow and black banded, or brown and yellow, and apparently mimic polistine vespids. Others, such as Rhynchophion, are metallic blue with violet and orange wings, and in flight closely resemble species of Pepsis (Pompilidae); some mesostenines twitch their wings while running and also can easily be mistaken for pompilids. A few pimplines are orange with black-banded wings and in flight they resemble noxious braconids (Quicke, 1990; Quicke et al., 1997). A few ichneumonids. most notably some species of Pimpla, Apechthis, and Exochus, emit a pungent odour when handled (Townes 1939) and this may serve to deter predators.
d. Evolutionary constraints and ground plan behavioral traits.
It is widely suggested that the more primitive apocritan (wasp-waisted) Hymenoptera develop from an egg that has been placed on an immobilized, concealed host by the adult parent. It is this habit of the female – providing the food for the offspring by choosing and immobilizing the host – that distinguishes the higher Hymenoptera from other carnivorous insects that simply lay their eggs near a food source but leave the task of seeking out and attacking the food to the larva. The hymenopteran habit of stinging, permanently immobilizing and rather rapidly consuming the larval food source is termed idiobiosis. Insects that do this are idiobionts. Most idiobionts feed externally on their hosts and they are referred to as ectoparasitoid idiobionts. The few that feed internally within the host are said to be endoparasitoids. Many species of ichneumonids, including the subfamilies Pimplinae, Rhyssinae, Xoridinae, Labeninae and Cryptinae, are ectoparasitic idiobionts. These ichneumonids typically attack concealed hosts, such as the larvae or pupae of endopterygote insects that are in tunnels and mines within plant tissue, or in galls. Most commonly, species of Lepidoptera, Symphyta, Diptera or Coleoptera are exploited as hosts. Many of the morphological adaptations shown by these idiobiont ichneumonids are specializations that enable them to gain ovipositional access to these concealed hosts (Gauld, 1988a). Since different ichneumonid species attack different hosts in subtly different locations, it is often relatively easy to discriminate the various ichneumonid species by differences in the length, shape and structure of the ovipositor
The adult female idiobiont ichneumonid permanently paralyses the host with a venom secreted by a gland associated with the ovipositor and injected during the ovipositional sequence. This ensures the host does not damage the delicate parasitoid egg. When the egg (which is usually rather large) rapidly hatches, the food source, alive but immotile, is free from decay. The parasitoid larva simply has to consume a defenseless bag of nutritive fluid and tissue. This type of behavior is relatively undemanding physiologically – i.e. the ichneumonid larva does not have to contend with any reaction against it by the host's immunodefensive system. Physiological constraints consequently have little to do with limiting host ranges. The species of host that the ichneumonid might encounter in a certain situation is therefore probably unimportant, so it is not surprising to find that some idiobionts have host ranges that embrace species belonging to several different orders. For example, Scambus sagax is known to attack species of Lepidoptera, Symphyta and Coleoptera associated with resinous galls, shoots or cones of conifers, whilst Endromopoda detrita has been reared from hymenopterous, lepidopterous and dipterous stem-borers of Poaceae (Fitton et al., 1988). In behavioral terms, host habitat location (a response to a chemical stimulus arising from the immediate environment the host occupies), seems to predominate over host location (a response to a chemical stimulus produced by the host itself).
e. Derived ectoparasitic traits.
f. Evolution of endoparasitism and koinobiosis.
Many insect larvae, such as the caterpillars of most larger moths, feed in an exposed situation, but they move to a substantially more concealed pupation site upon completion of feeding. If a feeding larvae was attacked by an idiobiont, it would be immobilized in a position where both it and its parasitoid would be highly vulnerable to scavengers, predators and other parasitoids. Such exposed hosts are generally not attacked by idiobionts until they are in concealment. There is, however, a clear selective advantage for any parasitoid that can oviposit onto the easily discoverable larval host stage but postpone permanent immobilization until after the host is in the pupation retreat. The retreat's protection will be afforded to the developing parasitoid as well. The strategy of allowing a host larva to develop for a time after oviposition is called koinobiosis (Askew & Shaw, 1986), It is widespread throughout the Ichneumonidae. Both ectoparasitoid and endoparasitoid forms of koinobiosis are known in the Ichneumonidae, although the former is a fairly uncommon life way.
Ectoparasitoid koinobiosis seems to have evolved separately in three subfamilies: the Adelognathinae, the Tryphoninae and the Polysphincta genus-group of the Pimplinae. At its simplest, as it occurs in the Adelognathinae, there is an apparent evolutionary transition from idiobiosis to incipient koinobiosis. One Adelognathus species develops as an idiobiont ectoparasitoid of a sawfly host concealed in plant tissue (Kopelke, 1987), another develops as an idiobiont ectoparasitoid of an exposed host (Rahoo & Luff, 1987), but several species are koinobiont ectoparasitoids of weakly concealed hosts (Fitton et al., 1982). In all cases, the adelognathine egg is simply glued on to the sawfly host and the emergent ichneumonid larva consumes the host quite rapidly. When fully grown, the adelognathine larva leaves the host and constructs a cocoon, either on the ground or in the host larval retreat (if present). This is a particularly unspecialized form of koinobiosis, since the parasitoid fails to exploit the abilities of the host to construct a more secure pupation retreat. Such a habit may have arisen because the parasitoid larva has been unable to avoid being discarded at the host larva's penultimate molt. Sawflies are particularly effective at being able to divest themselves of larval ectoparasitoids; unlike many other insects with caterpillar-like larvae, sawflies usually have a non-feeding final larval instar. When the sawfly larva is fully fed, it sheds its cuticle (and ectoparasites) before retreating to a pupation site.
A more specialized form of koinobiont ectoparasitism arose in the ancestors of the Tryphoninae. Tryphonines have a highly modified egg which is attached to the host by means of a stalk and anchor mechanism (Mason, 1967; Kasparyan, 1981), which apparently acts as an adaptation to retain purchase on a larval sawfly host during its penultimate molt. For example, Idiogramma species are koinobiont ectoparasitoids of xyelid sawfly larvae concealed in plant tissue, but idiogrammatines do not complete development until after the xyelid larva has vacated its mine in the host plant (immediately prior to which the xyelid molts) and has constructed a subterranean pupation retreat. Leaving the plant to pupate underground is advantageous for the host as it avoids being attacked as a prepupae or pupa by idiobiont ectoparasitoids. Molting prior to quitting the host-plant is selectively advantageous as it enables the xyelid to escape from primitive koinobiont ectoparasitoids. By circumventing the problem of ecdysis tryphonines have benefited from the first of their host's parasitoid avoidance strategies – they too escape the attentions of (facultatively hyperparasitic) idiobionts ovipositing through plant tissue.
Apart from avoiding being sloughed off during the host's penultimate molt, there are several other problems that koinobiont ectoparasitoids have had to overcome: vulnerability to attack by the host, and being subject to environmental factors such as desiccation. Tryphonines overcome the first problem by generally anchoring their eggs just behind the host's head, so the host cannot reach them with its mandibles (Baltensweiler & Moreau, 1957). In dry conditions the anchor stalk of the tryphonine egg may break (Morris et al., 1937), and so many tryphonines are restricted to attacking hosts in humid places or in partial concealment (Kasparyan, 1981). Some are nocturnal (e.g. Netelia spp.) and probably attack larvae that have completed feeding and are searching for pupation retreats (Vance, 1927; Schaff, 1972). The subfamily Lycorininae also has "stalk and anchor" eggs, and has avoided host attack and environmental factors by apparently attaching the egg to the cuticle inside the host's hind gut, using the ovipositor to probe up the anus (Shaw, 2004).
A unique and highly specialized form of ectoparasitoid idiobiosis occurs in the Polysphincta genus-group of the Pimplinae. The adult ichneumonid stings and temporarily immobilizes a spider on its web, and then carefully positions an egg on the immotile spider after first removing any other eggs that may be present. In many species, the ovipositor is only used for stinging the spider and the egg is extruded from the ovipositor's base. The spider recovers, continuing to feed and construct webs whilst the ichneumonid larva slowly grows, feeding through a minute integumentary lesion. The developing larva apparently produces a secretion that modifies the host's web-building behavior so that the spider constructs a web suitable for the wasp's pupation (Eberhard, 2000; Matsumoto, in press).
g. Endoparasitism and the problems with koinobiosis.
As mentioned previously, endoparasitoid koinobiosis necessarily involves a close physiological interaction between the parasitoid larva and its host. The host immune system is a major evolutionary barrier that endoparasitoids have had to overcome. The parasitoid has to prevent the host defenses from destroying it, yet at the same time it must not incapacitate the host lest both perish. Selective evolutionary pressures on koinobiont endoparasitoids could be primarily physiological, perhaps explaining why there is often very little obvious structural difference in extremely speciose genera such as Enicospilus, Lissonota, Glypta, Mesochorus, Orthocentrus, Campoplex and Dusona - all of which are cosmopolitan and each likely to comprise more than 2,000 species worldwide.
Koinobiont endoparasitoids have a variety of mechanisms to circumvent the defenses of the hosts (Salt, 1968; Vinson & Iwantsch, 1980; Guzo & Stoltz, 1987), but a number of these only work well against a very few hosts (Salt, 1975; Vinson & Stoltz, 1986; Ohsaki & Sato, 1990). Consequently the host range of koinobiont endoparasitoids is generally narrow in comparison to those of an idiobiont (Sheehan & Hawkins, 1991). For example, the endoparasitic koinobiont Enicospilus americanus only parasitizes a few species of Saturniidae (Gauld, 1988b), whilst the closely related tropical species E. lebophagus is restricted to just a single saturniid species, Rothschildia lebeau (Gauld, 1988c). Hyposoter PRO-3 has been reared on 114 of 115 occasions from a single species of Dyscophyllus (Hesperiidae) (Janzen & Hallwachs, 2008). In general, koinobiont endoparasitoids only attack hosts belonging to one or two families, or more usually, just a few species of one family.
The hosts of a great many koinobiont endoparasitic ichneumonids are the larvae of Lepidoptera (Banchinae, Ophioninae, most Anomaloninae, Stilbopinae, many Camplopleginae, Metopiinae, most Cremastinae, Ichneumoninae, and a few Ctenopelmatinae), and to a lesser extent, particularly in north temperate regions, the larvae of Symphyta (Collyriinae, most Ctenopelmatinae, some Campopleginae, a few Tersilochinae). Despite their huge diversity, the Coleoptera are attacked by only a relatively few specialized lineages of koinobiont ichneumonids: the Phrudinae, most Tersilochinae, a few Cremastinae, Anomaloninae and Acaenitinae, and a very few Campopleginae. Similarly the hyperdiverse order Diptera are attacked by only two koinobiont ichneumonid evolutionary lineages: the derived pimpliformes (Cylloceriinae, Orthocentrinae and Diplazontinae (Wahl, 1990)) - a lineage that only exploits the families Syrphidae, Tipulidae, Mycetophilidae and Sciaridae - and the stilpnine Cryptines which are larval/pupal parasitoids of cyclorrhaphous Diptera.
h. Gregariousness, secondary predation and hyperparasitism.
Whilst most ichneumonids develop on a single host as primary parasitoids, a few idiobionts may be facultative or even obligate hyperparasitoids. The tendency towards hyperparasitism is most pronounced in the endoparasitic koinobiont subfamily Mesochorinae where all species apparently develop as hyperparasitoids, usually of a braconid larva (the primary host) within a phytophagous larva (the secondary host).
Askew, R.R. & Shaw, M.R. 1986. Parasitoid communities: their size, structure and development. In: Waage, J. & Greathead, D. (eds.). Insect Parasitoids. Academic Press: London. 389 pp.
Arthur, A.P. & Wiley, H.G. 1959. Effects of host size on sex ratio, development time and size of Pimpla turionellae (L.) (Hymenoptera: Ichneumonidae). Entomophaga, 4: 297-301.
Aubert, J.-F. 1959. Biologie de quelques Ichneumonidae Pimplinae et examen critique de la theorie de Dzierzon. Entomophaga, 4: 75-188.
Austin, A.D. 1985. The function of spider egg sacs in relation to parasitoids and predators, with special reference to the Australian fauna. Journal of Natural History, 19: 359-376.
Baarlen, P. van, Topping, C.J., & Sunderland, K.D. 1996. Host location by Gelis festinans, an eggsac parasitoid of the linyphiid spider Erigone atra. Entomologia Experimentalis et Applicata, 81: 155-163.
Baltensweiler, W. & Moreau, J.P. 1957. Ein Beitrag biologisch-systematischer Art zur kenntnis der Gattung Phytodietus (Hymenoptera). Zeitschrift für Angewandt Entomologie, 41: 272-276.
Barrows, E.M. 1976. Sexual behavior in Hyposoter fugitiva (Hymenoptera: Ichneumonidae). Entomological News, 87: 101-102.
Beirne, B.P. 1941. A consideration of the cephalic structures and spiracles of the final instar larvae of the Ichneumonidae (Hym.). Transactions of the Society for British Entomology, 7: 123-190.
Bracken, G.K. 1965. Effects of dietary components on fecundity of of the parasitoid Exeristes comstockii (Cress.) (Hymenoptera: Ichneumonidae). Canadian Entomologist, 97: 1037-1041.
Bradley, W.G. & Burgess, E.D. 1934. The biology of Cremastus flavoorbitalis (Cameron), an ichneumonid parasite of the European corn borer. Technical Bulletin of the United States Department of Agriculture, 441: 1-15.
Carlson, R.W. 1979. Family Ichneumonidae. In: Krombein, K.V., P.D. Hurd, D.R. Smith, and B.D. Burks. Catalog of Hymenoptera of America North of Mexico. Vol. 1. Smithsonian Institution Press: Washington, D.C. 1198 pp.
Carton, Y. 1978. Biologie de Pimpla instigator (Hym.: Ichneumonidae) IV. Modalités du développement larvaire en function du site de ponte; rôle des reactions hémocytaires de l'hôte. Entomophaga, 23: 249-259.
Clausen, C.P. 1940. Entomophagous Insects. McGraw Hill: New York. 688 pp.
Coronado-Rivera, J., González-Herrera, A., Gauld, I.D. & Hanson, P.E. 2004. The enigmatic biology of the ichneumonid subfamily Lycorininae. Journal of Hymenoptera Research, 13: 223-227.
Daly, H.V., G.I. Stage & T. Brown. 1967. Natural enemies of bees of the genus Ceratina, (Hymenoptera: Apoidea). Annals of the Entomological Society of America, 60: 1273-1282.
Danthanarayana, W., Farrugia, D. & Gauld, I.D. 1977. Studies of the biology and systematic position of a new species of ichneumonid parasitizing the light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), in Australia. Bulletin of Entomological Research, 67: 607-617
Donovan, B.J. 1991. Life cycle of Sphecophaga vesparum (Curtis) (Hymenoptera: Ichneumonidae), a parasitoid of some vespid wasps. New Zealand Journal of Zoology, 18: 181-192.
Eberhard, W.G. 2000. The natural history and behavior of Hymenoepimecis argyraphaga (Hymenoptera: Ichneumonidae) a parasitoid of Plesiometa argyra (Araneae: Tetragnathidae). Journal of Hymenoptera Research, 9: 220-240.
Elliott, J.M. 1982. The life cycle and spatial distribution of the aquatic parasitoid Agriotypus armatus (Hymenoptera: Agriotypidae) and its caddis host Silo pallipes (Trichoptera: Goeridae). Journal of Anomal Ecology, 51: 923-941.
Evans, H.E. 1966. The Comparative Ethology and Evolution of the Sand Wasps. Harvard University Press: Cambridge. 526 pp.
Evans, H.E. 1968. Mexican and Central American Pompilinae (Hymenoptera, Pompilidae): supplementary notes, I. Entomological News, 79: 158-167.
Eggleton, P. 1990. Male reproductive behaviour of the parasitoid wasp Lytarmes maculipennis (Hymenoptera: Ichneumonidae). Ecological Entomology, 15: 357-360.
Finlayson, T. 1966. The false cocoon of Hyposoter paraorgyiae (Vier.) (Hymenoptera: Ichneumonidae). Canadian Entomologist, 98: 139.
Finlayson, T. 1975. The cephalic structures and spiracles of final-instar larvae of the subfamily Campopleginae, tribe Campoplegini (Hymenoptera: Ichneumonidae). Memoirs of the Entomological Society of Canada, 94: 1-137.
Fisher, R.C. 1959. The life-history and ecology of Horogenes chrysostictos (Gmelin) (Hymenoptera: Ichneumonidae), a parasite of Ephestia sericarum. Canadian Journal of Zoology, 37: 429-446.
Fitton, M.G. & Gauld, I.D. 1976. The family-group names of the Ichneumonidae (excluding Ichneumoninae) (Hymenoptera). Systematic Entomology, 1: 247-258.
Fitton, M.G. & Gauld, I.D. 1978. Further notes on family-group names of the Ichneumonidae (excluding Ichneumoninae) (Hymenoptera). Systematic Entomology, 3: 245-247.
Fitton, M.G., Gauld, I.D. & Shaw, M.R. 1982. The taxonomy and biology of the British Adelognathinae (Hymenoptera: Ichneumonidae). Journal of Natural History, 16: 275-283.
Fitton, M.G., Shaw, M.R. & Gauld, I.D. 1988. Pimpline Ichneumon-flies. Hymenoptera: Ichneumonidae (Pimplinae). Handbooks for the identification of British insects, 7(i): 1-110.
Flanders, S.E. 1956. The mechanisms of sex-ratio regulation in the (Parasitic) Hymenoptera. Insectes Sociaux, 3: 325-334.
Frilli, F. 1965. Studi sugli imenotteri ichneumonidi. 1. Devorgilla canescens (Grav.). Annali dell’Istituto di Entomologia Agraria dell Università di Bari, 1: 119-207.
Führer, E. 1975. Uber die physiologische Spezifität des polyphagen Puppenparasiten Pimpla turionellae L. (Hym., Ichneumonidae) und ihre ökologischen Folgen. Zentralblatt fur das gesamte Forstwesen, 92: 218-227.
Führer, E. & Kilincer, N. 1972. Die motorische Aktivität der endoparasitischen Larven von Pimpla turionellae L. und Pimpla flavicoxis Ths. in der Wirtspuppe. Entomophaga, 17: 149-165.
Gauld, I.D. 1976. The classification of the Anomaloninae (Hymenoptera: Ichneumonidae). Bulletin of the British Museum (Natural History). Entomology, 33: 1-135.
Gauld, I.D. 1984. An introduction to the Ichneumonidae of Australia. British Museum (Natural History): London. 413 pp.
Gauld, I.D. 1987. Some factors affecting the composition of tropical ichneumonid faunas. Biological Journal of the Linnean Society, 30: 299-312.
Gauld, I.D. 1988a. Evolutionary patterns of host utilization by ichneumonid parasitoids (Hymenoptera: Ichneumonidae and Braconidae). Biological Journal of the Linnean Society, 35: 351-377.
Gauld, I.D. 1988b. The species of the Enicospilus americanus complex (Hymenoptera: Ichneumonidae) in eastern North America. Systematic Entomology, 13: 31-53.
Gauld, I.D. 1988c. A survey of the Ophioninae (Hymenoptera: Ichneumonidae) of tropical Mesoamerica with special reference to the fauna of Costa Rica. Bulletin of the British Museum (Natural History) Entomology, 57(1): 1-309.
Gauld, I.D. 1991. The Ichneumonidae of Costa Rica, 1. Memoirs of the American Entomological Institute, 47: 1-589.
Gauld, I.D. 2002. The family Ichneumonidae. In: Gauld, I., Godoy,C., Ugalde, J. & Sithole, R. The Ichneumonidae of Costa Rica, 4. Memoirs of the American Entomological Institute, 66: 1-768.
Gauld, I.D. & Bolton, B. 1988. The Hymenoptera. Oxford University Press and British Museum (Natural History): Oxford. 332 pp.
Gauld, I.D. & Dubois, J. 2006. Phylogeny of the Polysphincta group of genera (Hymenoptera: Ichneumonidae; Pimplinae): a taxonomic revision of spider ectoparasitoids. Systematic Entomology, 31: 529-564.
Gauld, I.D. & Fitton, M.G. 1987. Sexual dimorphism in Ichneumonidae: a response to Hurlbutt. Biological Journal of the Linnean Society, 31: 291-300.
Gauld, I.D. & Janzen, D.H. 1994. The classification, evolution and biology of the Costa Rican species of Cryptophion (Hymenoptera: Ichneumonidae). Zoological Journal of the Linnean Society, 110: 297-324.
Gauld, I.D. & Wahl,D.B. 2000. The Townesioninae: a distinct subfamily of Ichneumonidae (Hymenoptera) or a clade of the Banchinae? Transactions of the American Entomological Society, 126: 279-292.
Gauld, I.D. & Ward, S. 2000. Subfamily Brachycyrtinae. In: Gauld, I. 2000. The Ichneumonidae of Costa Rica, 3. Memoirs of the American Entomological Institute, 63: 1-453.
Giraldo-Vanegas, H. & Garcia, J.L. 1992. Determinación del número de instares de Eiphosoma vitticolle Cresson (Hymenoptera: Ichneumonidae). Boletin de Entomologia Venezolana (N.S.), 7: 133-137.
Gordh, G. & Hendrickson, R. 1976. Courtship behavior in Bathyplectes anurus (Thomson) (Hymenoptera: Ichneumonidae). Entomological News, 87: 271-274.
Grimaldi, D. & Engel, M.S. 2005. Evolution of the Insects. Cambridge University Press: New York. 755 pp.
Gupta, V.K. 1987. The Ichneumonidae of the Indo-Australian area (Hymenoptera). Memoirs of the American Entomological Institute, 41: 1-1210.
Guzo, D. & Stoltz, D.B. 1987. Observations on cellular immunity and parasitism in the tussock moth. Journal of Insect Physiology, 33: 19-31.
Hrdy, I. & Sedivy, J. 1979. Males of Exetastes cinctipes (Hymenoptera, Ichneumonidae) attracted to 8-dodecenyl and 11-tetradecenyl acetates. Acta Entomologica Bohemoslovaca, 76: 59-61.
Hummelen, P.J. 1974. Relations between two rice borers in Surinam, Rupella albinella (Cr) and Diatraea saccharalis (F.) and their hymenopterous larval parasites. Mededelingen Landbouwhogeschool Wageningen, 74: 1-88.
International Commission on Zoological Nomenclature. 1994. Opinion 1757. Cryptus Fabricius, 1804 and Cryptinae Kirby, 1837 (Insecta, Hymenoptera) conserved. Bulletin of Zoological Nomenclature, 51: 74-75.
Iwata, K. 1958. Ovarian eggs of 233 species of the Japanese Ichneumonidae (Hymenoptera). Acta Hymenopterologica, 1: 63-74.
Iwata, K. 1960. The comparative anatomy of the ovary in Hymenoptera, Part.V. Ichneumonidae. Acta Hymenopterologica, 1: 115-169.
Janzen, D.H. 1981. The peak in North American ichneumonid species-richness lies between 38° and 42° N. Ecology, 62: 532-537.
Janzen, D.H. & Hallwachs, W. 2008. Database of rearings of Guanacaste Lepidoptera. http://janzen.sas.upenn.edu/
Jervis, M.A. & Kidd, N.A.C. 1986. Host-feeding strategies in hymenopteran parasitoids. Biological Review, 61: 395-434.
Jervis, M.A., Kidd, N.A.C., Fitton, M.G., Huddleston, T. & Dawah, H.A. 1993. Flower-visiting by hymenopteran parasitoids. Journal of Natural History, 27: 67-105.
Kasparyan, D.R. 1981. Ichneumonidae (Subfamily Tryphoninae). Tribe Tryphonini. Fauna of the USSR, 106: 1-414. Amerind Publishing Co.: New Delhi. 414 pp. [English translation of Russian original published in 1973, in Leningrad]
Kasparyan, D.R. 1993. Townesioninae, a new Ichneumonid subfamily from the eastern Palearctic (Hymenoptera: Ichneumonidae). Zoosystematica Rossica, 2: 155-159.
Kishi, Y. 1970. Difference in the sex ratio of the pine bark weevil parasite, Dolichomitus sp. (Hymenoptera: Ichneumonidae), emerging from different host species. Applied Entomology and Zoology, 5: 126-132.
Kopelke, J.-P. 1987. Adelognathus cubiceps Roman, 1924 (Ichneumonidae: Adelognathinae) – ein ungewöhnlicher Parasitoid der gallenbildenden Pontania-Arten (Tenthredinidae: Nematinae). Senckenbergia Biologia, 67: 253-259.
Mason, W.R.M. 1967. Specialization in the egg structure of Exenterus (Hymenoptera: Ichneumonidae) in relation to distribution and abundance. Canadian Entomologist, 99: 375-384.
Mathur, K.C. 1967. Notes on Apistephialtes sp., an ichneumonid larval parasite of Hypsiplya robusta Moore in India. Technical Bulletin of the Commonwealth Institute of Biological Control, 9: 133-135.
Matsumoto, R. 2005. A new host record of Ephialtes hokkaidonis Uchida (Hymenoptera: Ichneumonidae: Pimplinae) with a description of oviposition behavior. Bulletin of the Osaka Museum of Natural History, 59: 41-50.
Matsumoto, R. in press. "Veils" against predators: modified web structure of a host spider induced by an ichneumonid parasitoid, Brachyzapus nikkoensis (Uchida) (Hymenoptera). Journal of Insect Behaviour.
Matsumoto, R. & Saigusa, T. 2001. The biology and immature stages of Thrybius togashii Kusigemati (Hymenoptera: Ichneumnoidae: Cryptinae), with a description of the male. Journal of Natural History, 35: 1507-1516.
Miah, M.I. 1998. The phylogeny and taxonomy of the parasitic wasps subfamily Campopleginae (Hymenoptera, Ichneumonidae). Ph.D thesis, University of London.
Miah, M.I. & B.A. Bhuyia. 2001. The relationships of the subfamily Campopleginae (Hymenoptera, Ichneumonidae) with its related subfamilies in cladistic assessment. Proceedings of the Zoological Society (Calcutta), 54: 27-37.
Morley, C. 1915. Ichneumonologia Britannica 5. H & W Brown: London. 400 pp.
Morris, K.R.S., Cameron, E. & Jepson, W.F. 1937. The insect parasites of the spruce sawfly (Diprion polytomum Htg.) in Europe. Bulletin of Entomological Research, 28: 341-393.
Nuttall, M.J. 1973. Pre-emergence fertilization of Megarhyssa nortoni nortoni (Hymenoptera: Ichneumonidae). New Zealand Entomologist, 5: 112-117.
Ohsaki, N. & Sato, Y. 1990. Avoidance mechanisms of three Pieris butterfly species against the parasitoid wasp Apanteles glomeratus. Ecological Entomology, 15: 169-176.
Osman, S.E. 1978. Der Einfluss der Imaginalernährung und der Begattung auf die Sekretproduktion der weiblichen Genitalanhangdrüsen und auf die Eireifug von Pimpla turionellae L. (Hym., Ichneumonidae). Zeitschrift für Angewandt Entomologie, 85: 113-122.
Porter, C.C. 1998. Guiá de los géneros de Ichneumonidae en la region Neantártica del sur de Sudamérica. Opera Lilloana, 42: 1-234.
Price, P.W. 1973. Reproductive strategies in parasitoid wasps. American Naturalist, 107: 684-693.
Price, P.W. 1974. Strategies for egg production. Evolution, 28: 76-84.
Pschorn-Walcher, H. 1967. Biology of the ichneumonid parasites of Neodiprion sertifer (Geoffroy) (Hym.: Diprionidae) in Europe. Technical Bulletin of the Commonwealth Institute of Biological Control, 8: 7-51.
Pschorn-Walcher, H. & Zinnert, K.D. 1971. Investigations on the ecology and natural control of the larch sawfly (Pristophora erichsonii Htg. Hym.: Tenthredinidae) in Central Europe. Part II. Natural enemies: their biology and ecology, and their role as mortality factors in P. erichsonii. Technical Bulletin of the Commonwealth Institute of Biological Control, 14: 1-50.
Quicke, D.L.J. 1990. Tergal and inter-tergal metasomal glands of male braconine wasps (Insecta, Hymenoptera, Braconidae). Zoological Scripta, 19: 413-423.
Quicke, D.J. 2005. Biology and immature stages of Panteles schnetzeanus [sic] (Hymenoptera: Ichneumonidae), a parasitoid of Lampronia fuscatella (Lepidoptera: Incurvariidae). Journal of Natural History, 39: 431-443.
Quicke, D.L.J., Fitton,M.G., Notton, D.G., Broad G.R. & Dolphin, K. 2000. Phylogeny of the subfamilies of Ichneumonidae (Hymenoptera): a simultaneous molecular and morphological analysis. In: Austin, A.D. & M. Dowton (eds.). Hymenoptera: Evolution, Biodiversity and Biological Control. CSIRO: Collingwood. 467 pp.
Quicke, D.L.J, Fitton, M.G., Broad, G.R., Crocker, B., Laurenne, N.M. & Miah, M.I. 2005. The parasitic wasp genera Skiapus, Hellwigia, Nonnus, Chriodes, and Klutiana (Hymenoptera, Ichneumonidae): recognition of the Nesomesochorinae stat. rev. and Nonninae stat. nov. and transfer of Skiapus and Hellwigia to the Ophioninae. Journal of Natural History, 39: 2559-2578.
Quicke, D.L.J. & Shaw, M.R. 2004. Cocoon silk chemistry in parasitic wasps (Hymenoptera: Ichneumonoidea) and their hosts. Biological Journal of the Linnean Society, 81: 161-170.
Quicke, D.L.J., Wharton, R.A. & Sittertz-Bhatkar, H. 1997. Antero-lateral abdominal scent glands of braconine wasps (Hymenoptera: Braconidae). Journal of Hymenoptera Research, 6: 219-230.
Rahoo, G.M. & Luff, M.L. 1987. The biology of Adelognathus granulatus Perkins (Hym., Ichneumonidae) a parasitoid of the small gooseberry sawfly Pristophora pallipes (Lep.) (Hym., Tenthredinidae). Zeitschrift für Angewandte Entomologie, 104: 480-484.
Rasnitsyn, A. 1964. On hibernation of ichneumon-flies (Hymenoptera, Ichneumonidae). Entomologicheskoye Obozreniye, 43: 46-51.
Resh, V.H. & Jamieson, W. 1988. Parasitism of the aquatic moth Petrophila confusalis (Lepidoptera: Pyralidae) by the aquatic wasp Tanychela pilosa (Hymenoptera: Ichneumonidae). Entomological News, 99: 185-188.
Rojas-Rousse, D. & Benoit, M. 1977. Morphology and biometry of larval instars of Pimpla instigator (F.) (Hymenoptera: Ichneumonidae). Bulletin of Entomological Research, 67: 129-141.
Rotheray, G.E. 1981. Host searching and oviposition behaviour of some parasitoids of aphidophagous Syrphidae. Ecological Entomology, 6: 79-87.
Sandlan, K.P. 1979. Host-feeding and its effects on the physiology and behaviour of the ichneumonid parasitoid Coccygomimus turionellae. Physiological Entomology, 4: 383-392.
Salt, G. 1931. Parasites of the wheat-stem sawfly, Cephus pygmaeus, Linneaus, in England. Bulletin of Entomological Research, 22: 479-545.
Salt, G. 1952. Trimorphism in the ichneumonid parasite Gelis corruptor. Quarterly Journal of Microscopical Science, 93: 453-474.
Salt, G. 1968. The resistance of insect parasitoids to the defence reactions of their hosts. Biological Reviews of the Cambridge Philosophical Society, 43: 200-232.
Salt, G. 1975. The fate of an internal parasitoid, Nemeritis canescens, in a variety of insects. Transactions of the Royal Entomological Society of London, 127: 141-161.
Schaff, A.C. 1972. The parasitoid complex of Euxoa ochrogaster (Guenée) (Lepidoptera: Noctuidae). Quaestiones Entomologicae, 8: 81-120
Sharkey, M.J. & Wahl, D.B. 1992. Cladistics of the Ichneumonoidea (Hymenoptera). Journal of Hymenoptera Research, 1: 15-24.
Shaw, M.R. 1999. Gregarious development in endoparasitic koinobiont Ichneumonidae (Hymenoptera). Entomologist's Gazette, 50: 55-56.
Shaw, M.R. 2004. Notes on the biology of Lycorina triangulifera Holmgren (Hymenoptera: Ichneumonidae: Lycorininae). Journal of Hymenoptera Research, 13: 302-308.
Sheehan, W. & Hawkins, B.A. 1991. Attack strategy as an indicator of host range in metopiine and pimpline Ichneumonidae (Hymenoptera). Ecological Entomology, 16: 129-131.
Short, J.R.T. 1978. The final larval instars of the Ichneumonidae. Memoirs of the American Entomological Institute, 25: 1- 508.
Slobodchikoff, C.N. 1973. Behavioral studies of three morphotypes of Therion circumflexum (Hymenoptera: Ichneumonidae). Pan-Pacific Entomologist, 49: 197-206.
Slovák, M. 1983. To the larval development of the ichneumonid Exetastes cinctipes. Ustavu Experimentálnej Fytopatológie a Entomológie, 2: 233-244.
Smithers, C.N. 1956. On Philopsyche abdominalis Morley (Hym., Ichneumonidae), a parasite of Acanthopsyche junodi Heylaerts (Lep., Psychidae). Journal of the Entomological Society of South Africa, 19: 225-249.
Thibout, E. 2005. Role of caterpillar silk thread in location of host pupae by the parasitoid Diadromus pulchellus. Journal of Insect Behavior, 18: 817-826.
Tothill, J.D. 1922. The natural control of the fall webworm (Hyphantria cunea Drury) with an account of its several parasites. Bulletin of the Department of Agriculture of Canada, Entomological Branch, 19: 1-107.
Townes, H. 1939. Protective odors among the Ichneumonidae (Hymenoptera). Bulletin of the Brooklyn Entomological Society, 34: 29-30.
Townes, H. 1940. A revision of the Pimplini of eastern North America (Hymenoptera, Ichneumonidae). Annals of the Entomological Society of America, 33: 283-323.
Townes, H. 1969. The genera of Ichneumonidae, part 1. Memoirs of the American Entomological Institute, 11: 1- 300.
Townes, H. 1970a. The genera of Ichneumonidae, part 2. Memoirs of the American Entomological Institute, 12: 1- 537.
Townes, H. 1970b. The genera of Ichneumonidae, part 3. Memoirs of the American Entomological Institute, 13: 1- 307.
Townes, H. 1971. The genera of Ichneumonidae, part 4. Memoirs of the American Entomological Institute, 17: 1- 372.
Townes, H. & Townes, M. 1973. A catalogue and reclassification of the Ethiopian Ichneumonidae. Memoirs of the American Entomological Institute, 19: 1-416.
Townes, H. & Townes, M. 1966. A catalogue and reclassification of the Neotropic Ichneumonidae. Memoirs of the American Entomological Institute, 8: 1-367.
Vance, A.M. 1927. The biology and morphology of the braconid Chelonus annulipes Wesm., a parasite of the European corn borer. Technical Bulletin of the United States Department of Agriculture, 294: 1-48.
Veen, J.C. van. 1982. Notes on the biology of Banchus femoralis Thomson (Hym., Ichneumonidae) an endoparasitoid of Panolis flammea (D. & S.) (Lep., Noctuidae). Zeitschrift für Angewandte Entomologie, 94: 300-311.
Vinson, S.B. 1972. Courtship behavior and evidence for a sex pheromone in the parasitoid Campoletis sonorensis (Hymenoptera: Ichneumonidae). Environmental Entomology, 1: 409-414.
Vinson, S.B. & Iwantsch, G.F. 1980. Host regulation by insect parasitoids. Quarterly Review of Biology, 55: 143-165.
Wahl, D.B. 1990. A review of the mature larvae of Diplazontinae, with notes on larvae of Acaenitinae and Orthocentrinae, and proposal of two new subfamilies (Insecta: Hymenoptera, Ichneumonidae). Journal of Natural History, 24: 27-52.
Wahl, D.B. 1991. The status of Rhimphoctona, with special reference to higher categories within Campopleginae and the relationships of the subfamily (Hymenoptera: Ichneumonidae). Transactions of the American Entomological Society, 117: 192-213.
Wahl, D.B. 1993. Cladistics of the ichneumonid subfamily Labeninae (Hymenoptera: Ichneumonidae). Entomologia Generalis, 18: 91-105.
Wahl, D.B. & Gauld, I.D. 1998. The cladistics and higher classification of the Pimpliformes (Hymenoptera: Ichneumonidae). Systematic Entomology, 23: 265-298.
Wahl, D.B. & Mason, W.R.M. 1995. The family-group names of the Ichneumoninae (Hymenoptera: Ichneumonidae). Journal of Hymenoptera Research, 4: 285-293.
Yu, D.S. & Horstmann, K. 1997. A catalogue of World Ichneumonidae (Hymenoptera). Memoirs of the American Entomological Institute, 58: 1-1558.
Contents © 2002-present American Entomological Institute. All Rights Reserved.
Site credits and citation. Questions? E-mail: aei[at]aei.cfcoxmail.com