Braconidae show a variety of biologies.  Hosts are usually the larvae of Holometabola, although nymphs of Hemimetabola and adults of both Holometabola and Hemimetabola are also parasitized.  Two major lineages occur within this family, the cyclostome and non-cyclostome braconids.  Most species are endoparasitic koinobionts, although a large number are idiobiont ectoparasitoids.  idiobionts generally paralyze their hosts, lay an egg on or near the host, and begin consuming it immediately after the egg hatches.  Most idiobionts are ectoparasitoids (Sharkey 1993).  Koinobionts usually do not paralyze their prey, and typically an egg is laid inside the host.  The egg hatches immediately but undergoes a quiescent period while the host grows to an appropriate size and stage.  Koinobionts usually exercise some control over the development of their hosts (Vinson & Iwantsch 1980), and because they are closely associated with the life cycles of their hosts they have limited host ranges.  On the other hand, idiobionts are usually not closely synchronized with their hosts, and host ranges are generally quite large (Askew & Shaw 1986).  Ectoparasitism and the idiobiont development are ground-plan attributes of Braconidae (Sharkey 1993).  Nevertheless, both endoparasitism and koinobiosis appear to have developed a few times within the family.

 

There is no consensus on the number of braconid subfamilies, but Sharkey (1993) proposed 29 as follows:  Adeliinae, Agathidinae, Alysiinae, Amicrocentrinae, Aphidiinae, Apozyginae, Braconinae, Cardiochilinae, Cheloninae, Doryctinae, Dirrhopinae, Euphorinae, Gnamptodontinae, Helconinae, Homolobinae, Ichneutinae, Khoikhoiinae, Macrocentrinae, Meteoridiinae, Meteorinae, Microgastrinae, Miracinae, Neoneurinae, Opiinae, Orgilinae, Rogadinae, Sigalphinae, Trachypetinae and Xiphozelinae.

 
Key  references are Shenefelt 91965) who published a bibliography on Braconidae, Shenefelt (1969, 1970a, 1970b, 1972, 1973a, 1973b, 1974, 1975, 1978), Shenefelt & Marsh 91976), Fischer (1971), Mackauer & Stary (1967) and Mackauer (1968) catalogued the described species of Braconidae.  Shenefelt (1980) indexed his catalogs.  Tobias, Belokobylskij & Kotenko (1986) and Tobias, Yakimavichus & Kirijak (1986), building on the historic works of Telenga (1936, 1941, 1955) and Tobias (1975), keyed all the described species of Braconidae of European USSR.  Marsh (1979) cataloged the described species of Braconidae of North America.  marsh et al. (1987) keyed the genera of Braconidae occurring in North America.  Van Achterberg (1990) gave a key to the Holarctic subfamilies and (1984a) discussed their phylogenetic relationships.  „apek (1970) investigated larval braconids and discussed the phylogeny of Braconidae in light of larval morphology.  „apek (1973) gave a key to the larvae of braconid subfamilies.  Huddleston (1988) discussed Braconidae of Great Britain at the subfamily level.  Shaw & Huddleston (1991) provided a key to the subfamilies of Britain and discussed in great detail their biological attributes. 

​

Sharkey (1993) discussed the subfamilies of Braconidae by first dividing the family into its two major groups, noncyclostome and cyclostome.

 

Braconidae

​

Labrum not concave, usually sculptured, and often concealed beneath mandibles; vein m-cu of hind wing absent, except for a very small stub in specimens of Dirrhope and Acampsis; spiracle of metasomal tergum 2 usually (99%) on laterotergite; metasoma not bent between segments 2 and 3; species not parasitic on Aphidae (Homoptera).

All are endoparasitoids, most are koinobionts, though secondarily some have reverted to the idiobiont mode of parasitism. Female venom glands usually have the musculature reduced, suggesting little venom is used.  This seems probable in light of the fact that most hosts are parasitized when they are small compared with the parasitoid.

Interestingly, members of Ichneutinae have heavily muscled venom glands, and they parasitize the egg stage of their host.  When this occurs, the muscles may be necessary to counter the pressure in the egg.

 

The most common hosts are Lepidoptera larvae, followed by Coleoptera larvae.  Other hosts include Hemiptera nymphs and adults; Orthoptera and Psocoptera nymphs; adult Hymenoptera, Coleoptera and Chrysopidae (Neuroptera); and Symphyta larvae.  Typically, an early instar of the host is parasitized, the parasitoid egg hatches, and its development is arrested until the host is nearly full grown, at which time the parasitoid rapidly develops and consumes the host.  The parasitoid often oviposits into a host egg and delays development as described above.  The development of the host is often regulated so that the parasitoid emerges in synchrony with the next generation of hosts.  Members of Euphorinae and several other smaller groups oviposit into adult or nymphal insects, and some are idiobionts.

​

Adeliinae

Have vein Rs of forewing not tubular to wing margin; forewing without vein r; hind wing with vein A not tubular; transscutal suture present; metasomal terga 1-3 fused but not forming carapace over remaining terga. They are solitary endoparasitoids of leafmining Lepidoptera larvae.  Because of their close phylogenetic relationship with Cheloninae, members are possibly egg-larval koinobiont parasitoids.

Distribution is worldwide, although not recorded in the Neotropical or Oriental regions.  However, several species are in the Canadian National Collection from South America (Bolivia, Ecuador), and undoubtedly members will be found in the Oriental region as well; two genera.

​

Agathidinae (including Mesocoelus)

Have the forewing with cell lRs small or absent, with last abscissa of vein Rs close to stigma such that cell 2R1 narrow, and with wing fold between prestigma and vein 1/Rs; gena and mouthparts sometimes (25~o) elongate; occipital carina absent.

They are solitary koinobiont endoparasitoids of Lepidoptera larvae.  Most are diurnal, but about 1O% to 20% are nocturnal.  The last instar parasitoid larva leaves the body of the host and consumes the remains externally, except for the head capsule.

Agathidines spin a cocoon, which is often inside the cocoon spun by the final instar of the host.

Distribution is worldwide; 54 genera.  Sharkey (1986) discussed the rationale for including Mesocoelus in Agathidinae.

​

Amicrocentrinae

Have their body length more than 8 mm; occipital carina absent; epicnemial carina absent; forewing with cell lRs with five bordering veins; ovipositor about as long as forewing.  They are parasitoids of large, stem boring Lepidoptera larvae.  The pale yellowish brown color of adults suggests that they are nocturnal.

Distribution includes Madagascar and continental Africa; one genus (Amicrocentrum).

 

Cardiochilinae

Have the forewing with last abscissa of vein Rs weakly sclerotized and decurved, and with cell lRs present and distinctly wider than long; antenna with more than 16 flagellomeres; metasomal tergum 1 with spiracle on laterotergite; occipital carina absent; transscutal suture inflexible, superficial.

They are solitary koinobiont endoparasitoids of Lepidoptera larvae.  Distribution is worldwide; five genera.

 

Cheloninae

Have metasomal terga 1-3 fused, forming a carapace covering remaining terga; forewing with veins present though not always tubular; postpectal carina present anterior to mesocoxa; epicnemial carina absent.

They are solitary egg, larval koinobiont endoparasitoids of Lepidoptera.  The egg is laid in the host egg, and development of the parasitoid is arrested at the first instar larval stage until the host larva has prepared a pupation retreat (Shaw and Huddleston 1991).  Distribution is worldwide; seven genera.

​

Dirrhopinae

Have forewing with vein Rs not tubular to wing margin, and with vein r present; metatarsomere 1 with longitudinal comb of closely appressed setae; transscutal articulation groove like; metasoma not greatly constricted anteriorly, not petiolate; metasomal terga 1 - 3 not forming a carapace.

They are solitary endoparasitoids of leaf mining Lepidoptera larvae.  Because of their close phylogenetic relationship with Cheloninae they may be egg and larval koinobionts.  Described species are from the Palaearctic and Nearctic regions; undescribed specimens from South Africa and the Solomon Islands (Australian region) are in the Canadian National Collection; more collecting will likely extend the distribution to other regions; one genus (Dirrhope).

 

Euphorinae (including Centistini, and Ecnomios)

is a rather diverse and likely polyphyletic assemblage that is difficult to diagnose; metasoma usually (85%) petiolate; forewing with cell 2Cu open apically and with vein r - m usually (85%) absent; maxillary palpus usually (85%) 5 segmented

They are solitary, rarely gregarious, usually koinobiont endoparasitoids of several different orders of insects including the following, in order of frequency: Coleoptera, Hemiptera, Neuroptera, Psocoptera, Orthoptera and Hymenoptera.  Adult and nymphal stages are usually parasitized, although the larvae of Coleoptera are parasitized by a few members.  Distribution is worldwide; 63 genera.

 

Helconinae (comprising Blacini (including Dyscoletes, Brachistini, Brulleiini, Cenocoeliini, Diospilini and Helconini).  

Brulleiini, Cenocoeliini, Diospilini and Helconini have the occipital carina present; forewing with vein r-m present and with cell lRs quadrate or pentagonal; metasomal tergum 1 usually (95%) rugose and remaining terga smooth; metasomal tergum 1 not greatly narrowed anteriorly.  Blacini: occipital carina present; forewing with vein r-m usually (99%) absent (except Dyscoletes), and with vein 2cu-a usually (99%) absent (except members of Blacozona and Stegnocella); metasomal tergum 1 with dorsolateral pits.

Brachistini: occipital carina present; forewing without vein r-m and with vein 2cu-a usually (95%) present; metasomal tergum 1 with dorsolateral pits very weak or absent.

They are mostly koinobiont endoparasitoids of Coleoptera larvae.  Male mating swarms have been observed in several species of Blacus (Southwood 1957, Haeselbarth 1973).  Members of Dyscoletes (Blacini) are parasitic on Boreus larvae (Mecoptera) (Mason 1976). Distribution is worldwide; about 50 genera.

 

Homolobinae

(comprising Homolobini and Microtypini).  Homolobini: forewing with vein r-m present but not tubular; body usually (98%) yellowish brown; metasomal tergum 1 long, almost parallel-sided, and usually widest at the spiracles.  Microtypini: forewing and cell lRs triangular, vein A with an a' cross vein; occipital carinae and subpronope present.

They are solitary koinobiont endoparasitoids of Lepidoptera larvae.  Most (90%) species are nocturnal.  Distribution is worldwide; four genera.

 

Ichneutinae

have the dorsal longitudinal carina of propleuron usually (95%) absent; occipital carina absent; epicnemial carina often (50%) absent; metasomal terga 1-3 not forming a carapace.

Members of the tribe Ichneutini and Proteropini are solitary koinobiont larval parasitoids of larval Symphyta; those of Muesebeckiini parasitize leaf mining Lepidoptera.  The egg or first instar larva of the host is parasitized, and development is delayed until the host larva has spun its cocoon.  Distribution is worldwide; nine genera.

​

Khoikhoiinae

 have metasomal tergum 1 with spiracle on laterotergite; transscutal articulation functional, groove like, not superficially impressed; forewing with apical abscissa of vein Rs spectral or nebulous; epicnemial carina absent.

Their biology is unknown, but based on their close relationship to Cardiochilinae, members of Khoikhoiinae are likely solitary koinobiont endoparasitoids of Lepidoptera larvae.  They are found in South Africa; two genera.

 

Macrocentrinae

 (including Chamton). Charmonini: forewing without vein r-m; occipital carina reduced dorsally; hind wing with vein 2a'.  Macrocentrini: metatrochantellus with spines; occipital carina absent; body usually (95%) yellowish brown; sclerotized bridge present between metacoxal cavities and propodeal foramen.

They are solitary or gregarious endoparasitoids of early to late instar Lepidoptera larvae.  Some gregarious species of Macrocentrus are known to be polyembryonic; many species are nocturnal.  Distribution is worldwide; eight genera.

 

Meteoridiinae

have the hind wing with vein 2/Cu; forewing with cell lRs quadrate and with vein 2cu-a present.

They are larval-pupal endoparasitoids of Lepidoptera.  Eggs are laid into the host larvae, but adults emerge from the host pupae.  Distribution is worldwide; two genera.

 

Meteorinae

 (including Zele) have metasomal tergum 1 usually (95%) much narrower anteriorly than posteriorly; forewing with vein r-m present and with cell lRs quadrate; metacoxal cavities not separated from propodeal foramen by sclerotized bridge; metasomal tergum 1 often (80%) with deep dorsal pits.  Some researchers consider the two included genera to be members of Euphorinae and others treat them as separate monotypic subfamilies.

They are solitary or gregarious koinobiont endoparasitoids of Coleoptera or Lepidoptera larvae.  Some species of Meteorus that parasitize Lepidoptera larvae suspend their cocoons from a line of silk resembling a meteor, hence the generic name.  Many species of Meteorus and Zele are nocturnal.  Some species are idiobionts.  Distribution is worldwide; two genera.

 

Microgastrinae

 have forewing with last abscissa of vein Rs not tubular; metasomal tergum 1 with spiracle on laterotergite; occipital carina absent; antenna with 16 flagellomeres (because of a median constriction in each flagellomere, the flagellum may appear to have 32 articles); apical (ventral) margin of clypeus concave.

They are solitary or gregarious koinobiont endoparasitoids of Lepidoptera larvae (see Shaw and Huddleston, 1990, for a detailed summary).  Usually koinobionts, sometimes egg and larval parasitoids.

Distribution is worldwide; 52 genera (largest braconid subfamily in terms of number of species).

 

Miracinae

 have the forewing with last abscissa of vein Rs not sclerotized and without vein r-m; metasomal tergum 1 with spiracle on membranous laterotergite; antenna with 12 flagellomeres.

They are solitary endoparasitoids of leaf mining Lepidoptera larvae.  Distribution is worldwide; two genera.

 

Neoneurinae

 have the epicnemial carina absent; occipital carina absent; maxillary palpus with 3 segments; labial palpus with 2 segments; metasomal terga with setae scattered over surface and not restricted to posterior transverse row.  This subfamily may be a derived lineage of Centistini (Euphorinae).  Some attributes that suggest this supposition are parasitization of adult insects, laterally compressed ovipositor, and specialized pit like antennal sensilla.

They are internal parasitoids of adult Formicidae.  The ovipositor is greatly curved and is thrust directly into the gaster of the adult ant.  Distribution is Holarctic, including northern Africa; two genera.

 

Orgilinae

 have the forewing with vein r-m usually absent but, if present, then cell 1-Rs triangular, and vein A lacking anal crossveins; occipital carina usually (90~o) present; no wing fold between vein 1/Rs and stigma; dorsal pit absent; vein 2cu-a of forewing present.  Antestrix, known only from two Chilean species, is not included in this diagnosis.

 They are solitary koinobiont endoparasitoids of Lepidoptera larvae.  Distribution is worldwide; seven genera.

 

Sigalphinae

 (including Acampsis, Minanga, Neoacampsis, Pselaphanus and Sigalphus) have the occipital carina absent dorsally; forewing with free apical abscissa of vein Cu present and with vein r-m present; metacoxal cavities open to propodeal foramen and not separated by sclerotized bridge; metasomal tergum 1 usually (95~O) with pair of percurrent longitudinal carinae.

They are solitary endoparasitoids of Lepidoptera larvae.  Distribution is worldwide; five genera.

 

Trachypetinae

 have their forewing with cell lRs pentagonal; ovipositor barely exerted; antennal flagellomere with more than 50 articles.

Biology is unknown.  Sharkey (1993) suspects, based on presumed phylogenetic affinites, that members are endoparasitoids of Lepidoptera larvae.  More than half of the known specimens have been collected at light in desert habitats (A.D. Austin, pers. commun.). They are found only in the Australian region; three genera.

 

Xiphozelinae

 have the occipital carina absent; sclerotized bridge between metacoxal cavities and propodeal foramen; hind wing with cell lCu much longer on posterior margin than on anterior margin (vein lA much longer than vein M+Cu); metasomal segment 1 with median tergite more than five times as long as apical width.

They are solitary nocturnal endoparasitoids of Noctuidae (Lepidoptera) larvae.  Distribution is Palaearctic, Oriental, and Australian regions; two genera.

 

    Cyclostome Braconidae

 

The labrum is usually (70%) concave, smooth, and often (80%) mostly glabrous (many Doryctinae have microsculpture and many setae on the labrum, but in those forms the labrum is distinctly concave); many members without these attributes have exodont mandibles; hind wing with vein m-cu often (50%) present; metasomal tergum 2 with spiracle usually (90%) on median tergite.  Members of Aphidiinae, which are here associated with the cyclostomes for the first time, do not share some of the more obvious diagnostic attributes of the other cyclostomes.  They are best diagnosed by the following: joint between metasomal terga 2 and 3 flexible; metasoma often (50%) bent ventrally between segments 2 and 3; hind wing with vein lA and vein cu-a absent or spectral, never sclerotized, and with long sensory setae near junction of veins R and lr-m; parasitoids of Aphidae (Homoptera).

 

Most are idiobiont ectoparasitoids of Lepidoptera larvae and Coleoptera, although many members are endoparasitoids of Diptera, Aphidae (Homoptera) and Lepidoptera, and many of these are koinobionts.  Isoptera and Embioptera are also known hosts and one genus may be phytophagous (Marsh 1991).  Most females have well muscled venom glands and use venom to subdue their prey and paralyze it, at least temporarily.  Development of the parasitoid usually begins immediately, with little or no visible effect on the development of the host, which is quickly consumed.

 

Alysiinae

have their mandibles exodont, not touching when closed; epicnemial carina absent; occipital carina absent; hind wing with vein 2m-cu often (50%) present.  Alysiinae is a derived lineage of the paraphyletic subfamily Opiinae (Buckingham and Sharkey 1988).

Most (90%) are solitary koinobionts and all are endoparasitic on Cyclorrhapha (Diptera) larvae.  Distribution is worldwide, but much more speciose in temperate regions; 65 genera.

 

Aphidiinae

 have their antenna usually (80%) curved ventrally in dead specimens; flexible joint between metasomal terga 2 and 3 (in dead specimens the metasoma is often (50%) bent at this point); hind wing with veins lA and cu-a absent or not tubular; parasitic on Aphidae (Homoptera). Aphidiinae is placed with the idiobiont (cyclostome) Braconidae because of the presence of the following apomorphies: hind wing with anterior margin excavated basally and with long sensory setae present near junction of veins R and r-m; metasomal terga weakly sclerotized, labrum smooth, triangular, and mostly glabrous; and host mummified (as in most Rogadinae).

They are solitary koinobiont endoparasitoids of Aphidae (Homoptera) nymphs and adults.  Distribution is worldwide, but more speciose in temperate regions; about 51 genera (P. Stary, pers. commun.).

 

Apozyginae

 have the forewing with vein 2m-cu; labrum glabrous and concave; hind wing with vein 2/Cu.  Apozyginae is treated by Sharkey (1993) as a subfamily of Braconidae rather than as a distinct family as originally proposed by Mason (1978, 1987). Sharkey and Wahl (1992) justified this placement.

Their biology is unknown, but judging from a general similarity to some Doryctinae members are possibly idiobiont ectoparasitoids of xylophagous Coleoptera larvae.  They are found in Chile; one genus with one species, Apozyx penai Mason.

 

Braconinae

 (including Vapellina) have the labrum concave; occipital carina absent; epicnemial carina absent; hind wing with vein 1/M at least twice as long as M+Cu.

Most species are idiobiont ectoparasitoids of concealed larvae of xylophagous and stem boring Coleoptera and Lepidoptera larvae, and rarely of Diptera and Symphyta.  Several genera are gregarious endoparasitoids of Lepidoptera pupae (van Achterberg 1984b, Quicke 1987a).  Distribution is worldwide; 151 genera.

 

Doryctinae

 (including Histeromerus) have the labrum concave; protarsus usually (99%) with spines along anterior margin; occipital carina present but usually (80~) absent ventrally; epicnemial carina present.

They are mostly solitary idiobiont ectoparasitoids of xylophagous and stem boring Coleoptera larvae, though one genus is known to parasitize Embioptera (Shaw and Edgerly 1985) and another may be phytophagous (Marsh 1991).  Distribution is worldwide; 75 genera.

 

Gnamptodontinae

 (including Telengaia) have the labrum concave to flat; forewing with cell 2Cu open (vein lA incomplete); metasomal tergum 2 with smooth, anterior, transverse elevation; propodeum without sculpture. Telengai is similar to most gnamptodontines.  Members have a modified metasoma, but wing venation and head and mesosomal structures lead me to believe that Gnamptodontinae, including Telengaia is monophyletic.

These are parasitoids of leaf mining larvae of Nepticulidae (Lepidoptera).  It is not known if they are endoparasitoids or ectoparasitoids, but based on their possible sister group relationship with Opiinae plus Alysiinae (Buckingham and Sharkey 1988).  They are believed to be endoparasitoids.  Distribution is worldwide; four genera.

 

Opiinae

 (including Mesostoa) have the epicnemial carina absent (except Ademon); occipital carina often (85%) absent dorsally but usually (98%) present laterally; occipital carina, when present, usually (98%) meeting subgenal carina, not hypostomal carina; hind wing with vein 2m-cu often (50%) present; clypeus with ventral margin usually (90%) not concave.  Van Achterberg (1975) proposed Mesostoa as a separate monotypic subfamily.  It is included here in the Opiinae based on the shared possession of the following: labrum not greatly concave; clypeus straight ventrally; epicnemial carina absent; ovipositor bent dorsally. Opiinae is paraphyletic in that Alysiinae is a derived lineage of this assemblage (Buckingham and Sharkey 1988).

They are solitary endoparasitoids of Cyclorrhapha (Diptera) larvae.  As with members of Alysiinae, they often parasitize a late larval instar, but they are also known to parasitize eggs and early instar larvae.  Distribution is worldwide; 17 genera; most species are in the large genus Opius, which is divided into about 50 sub-genera.

 

Rogadinae

 (including Exothecini, Hormiini, Lysterimini, Pambolini, Rhyssalini, Rhysipolini, Hydrangiacolini, Rogadini and Ypsistoceratini).  Sharkey (1993) commented that this subfamily is certainly not monophyletic.  Many of the constituent tribes have been placed in other subfamilies (Doryctinae) or have been treated as independent subfamilies.  Because the relationships of these taxa are poorly understood, he adopted a very broad definition of Rogadinae.  Most of the tribes comprising the Rogadinae are discussed and diagnosed separately as follows:

 

​

Tribe Exothecini

Labrum concave; occipital carina ending ventrally on subgenal carina or absent ventrally but present at least laterally; epicnemial carina absent.These are idiobiont ectoparasitoids of concealed (usually leaf mining) Lepidoptera, Diptera, Coleoptera, and Symphyta larvae. Distribution is probably worldwide; five genera.

 

Tribes Hormiini, Lysterimini and Pambolini

Labrum concave; metasomal tergum 2 with spiracle on median tergite or near margin of median and lateral tergites; occipital carina absent ventrally or meeting hypostomal carina; metasomal tergum 1 without median longitudinal carina, often (80%) with 2 percurrent longitudinal carinae; protibia without pegs or spines; epicnemial carina present.  Hormiini: metasomal terga, except first, membranous.  Lysterimini: metasomal segments 1-3 with median tergites heavily sclerotized and sculptured and usually covering following terga.  Pambolini: propodeum often with posterolateral spine or bump; metasomal terga 2 and 3 not membranous, usually smooth, but if sculptured then not covering following terga.

Members of Hormiini and Lysterimini are usually gregarious ectoparasitoids of concealed Lepidoptera larvae.  Members of Pambolini are solitary ectoparasitoids of Coleoptera and Lepidoptera larvae.  Distribution is worldwide; about 15 genera.

 

Tribe Rhyssalini

Labrum concave; metasomal tergum 2 with spiracle on laterotergite, well below margin of median tergite; occipital carina ending ventrally on hypostomal carina; metasomal tergum 1 without median longitudinal carina, or metasoma not coarsely sculptured beyond tergum 1, or both; protibia without spines or pegs on anterior surface.

They are usually gregarious, sometimes solitary, idiobiont ectoparasitoids of Coleoptera and Lepidoptera larvae.  Distribution is worldwide (Australian?); five genera.

 

Tribe Rhysipolini (including Hydrangiacolini)

Labrum concave; occipital carina ending ventrally on subgenal carina; metasomal tergum 1 without median longitudinal carina, or metasoma not coarsely sculptured beyond tergum 1, or both; anterior surface of protibia without pegs and spines.

They are koinobiont ectoparasitoids of Lepidoptera larvae.  Distribution is worldwide; seven genera.

 

Tribe Rogadini (including Betylobracon, Leurinion and Ypsistoceratini)

Occipital carina present; labrum usually (95%) concave; metasomal tergum 1 usually (95%) with sharp median longitudinal carina; metasomal terga 3 and 4 also often (75%) have median longitudinal carina; protibia without pegs and spines on anterior surface.

Leurinion is usually placed in Hormiinae because, as in members of Hormiinae, the median tergites of some metasomal segments are membranous.  However, this attribute occurs in several other cyclostome subfamilies including members of Rogadinae, e.g., Aeliodes excavatus (Telenga).  Furthermore, the membranous portions of the metasomal terga of Leurinion species are more widespread than the membranous proportions of Hormiinae species and include the posterior part of tergum 1.  Members of Leurinion have a sharp median longitudinal carina on the propodeum and metasomal terga 2 and 3.  This combination of derived characters is unknown outside Rogadinae

 

Ypsistoceratini, composed of Ypsistocerus, Terrnitobracon and an undescribed genus from the southeastern USA, are sometimes placed in their own subfamily.  They are a derived group morphologically and have lost many attributes that allow for their easy placement in any cyclostome subfamily.  They share several derived characters with the rogadine genus Yelicones: expanded apical tarsomeres of all legs and the presence of spines on the anterior surface of the protibia.

 

 

Tobias (1979) placed Betylobracon in its own subfamily.  However, based on the presence of a strong m-cu' vein in the forewing (a derived character within the idiobiont Braconidae) and metasomal spiracles located on the median tergites (a primitive character that excludes it from the koinobiont Braconidae) it appears to belong to the idiobiont lineage.  Of the subfamilies in this lineage it appears to be closely related to Yelicones and allies.  This is shown by the following: femora swollen, apical tarsomeres swollen and elongate, and ovipositor short (shared by all Rogadini). Betylobracon waterhousei Tobias, the only species described to date, bears a striking resemblance to Yelicones delicatus (Cresson).  The principal difference between the two species is that the clypeus of the former is not concave ventrally, but this character state reversal is not uncommon within the idiobiont clade.

​

These are koinobiont endoparasitoids of Lepidoptera larvae; pupation takes place inside the mummified remains of the host, except for members of Leurinion, which do not mummify their hosts.  The biology of members of Ypsistoceratini is unknown, but they have been associated with termite nests (Isoptera).  Distribution is worldwide; about 45 genera.

 

​

Further Description

 

Braconidae continue to be of considerable value in biological control.  Ischiogonus syagrii Ful. was imported into Hawaii from Australia in 1921 in a successful effort of control against the fern weevil, Syagris fulvitarsis Pasc. Opius fletcheri Silv, a parasitoid of the melon fly, Bactrocera curcurbitae Coq., and O. tryoni Cam., attacking Mediterranean fruit fly, Ceratitis capitata Wied., have been credited with appreciable reduction of these two pests in Hawaii and have allowed the continued growing of certain fruits and vegetables that were previously heavily infested.  The reduction in infestation of C. capitata in coffee was particularly important. Apanteles solitarius Ratz and Meteorus versicolor Wesm., both of European origin, have been responsible for adequate control of the satin moth, Stilpnotia salicis L. in some parts of North America (Clausen 1940/1962). Apanteles oenone Nixon and Chelonus sp. nr. curvimaculatus Cameron are considered probable good candidates for importation against the pink bollworm, Pectinophora gossypiella Saunders, attacking cotton (E. F. Legner, unpub. data), as they are associated with low densities of the pest in its endemic range in northwestern Australia.

 

 

Host Preferences

Regarding host preferences, because of the large number of species involved and the extensive studies that continue to be made, host preferences will be discussed using the Clausen (1940/1962)format, on the basis of principal subfamilies.  There is an exceptional uniformity of habit within these groups, not only in the choice of hosts but in the manner of development (Clausen 1940/1962).

 

Vipioninae

 are principally external parasitoids of the larvae of Lepidoptera, though a considerable number attack coleopterous larvae and a few species are parasitic on those of sawflies and Diptera (Cecidomyiidae).  The dominant genus is Microbracon, which is cosmopolitan and attacks a wide range of hosts.  Practically all hosts attacked by members of this subfamily are contained in a cell, burrow or cocoon or are protected by a web.  Free-living larvae normally are not subject to attack, though an undetermined species of Microbracon parasitizes the uncovered larvae of the teak leaf skeletonizer, Hapalia machaeralis Wlk.  in India and M. brevicornis Wesm. attacks the free-living larvae of Heliothis in South Africa (Beeson & Chatterjee (1935).  Most species are gregarious in habit, although the number developing on each individual host is small.  An occasional species is predaceous rather than parasitic, such as M. lendicivorus Cush. (Williams 1928), which develops at the expense of the larvae of the cecidomyiid, Asphotrophia fici Barnes.  These larvae live in the receptacles of the fruit of Ficus nota in the Philippines (Clausen 1940/1962).

 

Spathiinae and Doryctinae

Few studies have been made on the Spathiinae and Doryctinae, but the species seem to attack principally the larvae of bark and wood-boring Coleoptera.  The genera most commonly encountered are Spathius, Doryctes and Dendrosoter, which are externally parasitic.

 

Rhogadinae

 are apparently limited in their host preferences mainly to the larvae of Lepidoptera, on which they develop internally. Rogas is the most common genus of the subfamily. Oncophanes lanceolator Nees differs in habit from others of the subfamily in developing as a gregarious external parasitoid.

 

Cheloninae

are mainly solitary internal parasitoids of lepidoptera larvae.  The genera Ascogaster, represented by the codling moth parasitoid A. quadridentata Wesm. (carpocapsae Vier.), Phanerotoma, and Chelonus, are restricted to lepidopterous hosts and have the habit of ovipositing in the egg and completing their larval development when the host larva is nearly mature.  Such behavior makes it difficult to understand how they might be valuable in biological control, since the host continues to cause damage even though parasitized in the larval stage.  However, the impact on the population in precluding adult reproduction may be profound, and should not be underestimated over the long term.

 

Triaspinae

 are parasitic in the larvae of Bruchidae and occasionally Curculionidae, but little information is available on the manner of attack and development. Triaspis is frequently reared from weevil-infested beans, peas and other seeds (Clausen 1940/1962).

 

Neoneurinae

Little information is available on host preferences of the Neoneurinae. Elasmosoma berolinense Ruthe is reported attacking adult ants of Formica fusca var. japonica Motsch (Kariya 1932).  The female pounces on the ants at the entrance to the nest and inserts the ovipositor into the abdominal region.  Observations on American and European species point also toward a relationship with ants (Clausen 1940/1962).

 

Microgasterinae

 are limited in their host preferences principally to lepidoptera larvae, and many of the hosts are fee-living in habit.  Dominant genera that are very common are Apanteles, Microgaster and Microplitis.  Development takes place internally, the only apparent exception being A. canarsiae Ashm., which was recorded as a solitary external parasitoid of the larva of Desmia funeralis Hbn. by Strauss (1916).  Clausen (1940/1962) considered this record questionable, however, because it may be based on observations made during the very short period of external feeding which occurs in some species between emergence from the host body and spinning of the cocoon.

 

Braconinae

 are most often found as parasitoids of lepidopterous caterpillars, though some species attack trypetid and curculionid larvae.  Species of the well known genus Bassus develop internally in lepidopterous larvae of shoot or stem boring habit.

 

Blacinae

Little is known regarding the host preferences of the Blacinae. Eubadizon and Orgilus are parasitic in lepidopterous larvae, whereas Syrrhizus attacks adult chrysomelid beetles of the genus Diabrotica.

​

Macrocentrinae

 are solitary or gregarious internal parasitoids of lepidopterous larvae.  The dominant genus Macrocentrus is well studied by virtue of its attack of the European corn borer and oriental fruit moth.  Initial attack is on the young larva in its burrow, and parasitoid development is completed when the host larva is full grown.

 

Opiinae

Information on the Opiinae is principally from the genus Opius, many species of which are parasitic in dipterous larvae of the family Trypetidae, though a number of species have been reared from Agromyzidae.  Oviposition is in the maggot in almost any stage of development, and adult emergence is from the host puparium.

 

Euphorinae

 are distinctive in that the majority of species are internal parasitoids of adult Coleoptera.  The well known genus Perilitus (Dinocampus) is confined in its host preferences to Coccinellidae and Curculionidae, while Microctonus attacks mainly the Curculionidae, Chrysomelidae and Tenebrionidae. Perilitus is solitary but in some species of Microctonus a large number may develop in a single host. Aridelus attacks nymphs and adults of Pentatomidae and Euphorus and Euphoriana are parasitic in Miridae (Muesebeck 1936).  Exceptions to the above generalization are that M. aethiops Nees has been reared from adults and larvae of Phyllotreta and Sitona, and M. brevicollis Hal. has its first generation in the larvae of Haltica ampelophaga Guer. and the second generation in adult beetles (Kunckel D'Herculais & Langlois 1891).

 

Meteorinae

 are solitary or gregarious internal parasitoids of the larvae of many Lepidoptera and have also been recorded from those of bark and wood-boring Coleoptera.  Extensive studies exist on the habits of a number of species of Meteorus, the single genus of the subfamily.  Oviposition occurs in young host larvae while they are exposed, and development is completed before the pupal stage is attained.  Some species produce two complete generations upon one brood of host larvae, the first being upon very young individuals and the second upon those which are nearly mature (Clausen 1940/1962).

 

Aphidiinae

 are very consistent in their host preferences, and all species that have been studied are solitary internal parasitoids of Aphididae. They can be very effective in reducing infestations of their hosts, even though this usually takes place after the latter have reached a high population density and considerable crop injury has already occurred.  Clausen (1940/1962) believed that this was due to the ability of the aphids to reproduce at lower temperatures than the parasitoids, and the pest population attains a relatively high abundance before conditions for parasitoid development become favorable.  Common genera are Aphidius, Lysiphlebus, Praon and Ephedrus.

 

Alysiinae

There have been no extensive studies on Alysiinae, but common members are the genera Alysia and Dacnusa, internal parasitoids of Diptera. Alysia is more particularly a parasitoid of blowflies of the genera Sarcophaga, Lucilia and Calliphora, and the adult emerges from the puparium.  Extended studies of A. manducator Panz., have been made by Graham-Smith (1916, 1919), Altson (1920), Myers (1927a), Salt (1932) and Holdaway & Smith (1932).  Also some species of Dacnusa attack the larvae and emerge from the puparia, principal hosts being Agromyzidae.

 

 
Biology and Behavior

 

The position of the host larvae with respect to the plant may influence parasitoid attack (Cushman 1926a).  A parasitoid species may attack two or more hosts that are widely separated taxonomically but have the same relationship to the plant, whereas closely related species, that are of different habits, are not subject to attack.  Cushman concluded that the relationship of the host insects to the plant, rather than taxonomic relationships, often governs the choice of hosts by the parasitoid.  This applies not only to many Braconidae but to various other parasitic groups and even to some predators as is discussed under the section on "Host Selection."  Other early authors recognized the close association of a parasitoid species with a particular plant species or group, which limits their attack to insects infesting those plants.  Picard (1919) in studies of insects associated with fig trees, concluded by Sycosoter lavagnei P. & L. is primarily attracted to fig trees rather than to the particular coleopterous species which it parasitizes.  Taylor (1932) reported that in South Africa Microbracon brevicornis attacks larvae of Heliothis armigera Hbn. on Anthirrhinum only, even though caterpillars are present on an array of other plants.

 

The host food plant often has a major influence on the extent of parasitization, which is demonstrated by the case of Apanteles congregatus, parasitoid of Phlegothontius larvae in North America.  When larvae feed on wild Solanaceae, parasitization can be very high.  Morgan (1910) noted that larvae occurring on tobacco are seldom parasitized, and he thought that parasitized individuals found upon this plant may have moved to it from native vegetation.  The difference in degree of successful attack is believed due probably to the toxic effect of the caterpillar's food on the early stages of the parasitoid (Clausen 1940/1962).  Additional observations on Apanteles parasitization of Phlegothontius were made by Gilmore (1938), who found that lack of effective parasitization was most pronounced when the host occurred on dark-fired tobacco.  Larvae feeding only on such foliage were frequently parasitized but the Apanteles larvae were unable to develop to maturity.  The nicotine content of this tobacco is high, and it was thought that this toxic character may be present in sufficient concentration in the host blood to bring about the death of the parasitic larvae.

 

The quantity and quality of parasitoid or predator progeny on different hosts seem to vary in the insectary according to evolutionary contact, as mentioned by Legner & Thompson (1977).  Their study compared the suitability of the potato tuberworm and the pink bollworm, the original source host, as hosts for a braconid, Chelonus sp. nr. curvimaculatus Cameron.  It was found that after being reared for many generations on the potato tuberworm, and then for one generation on pink bollworm, the parasitoid was stimulated to increase its destruction of and fecundity on the factitious host.  This group of Chelonus parasitoids responds to kairomones in the body scales of several lepidopterans (Chiri & Legner 1986), and might be characterized as generalists.

 

Regarding biology and behavior, parasitism by braconids may be either external or internal, and modifications in habit are correlated with habits of the host stages that are subjected to the attack.  Generally, internal parasitism occurs if the hosts are free-living as in the case of adult beetles attacked by the Euphorinae and other groups, the foliage-feeding lepidopterous larvae by Microgasterinae, Meteorinae, etc., and the aphids that serve as hosts of the Aphidiinae (Clausen 1940/1962).  However, external parasitism is general in hosts that live in confined quarters and thus the Vipioninae, attacking principally caterpillars in tunnels, leaf rolls, etc., and the groups that occur on the larvae of bark and wood-boring Coleoptera, develop externally.  The latter groups complete development on the host instar upon which the egg was laid.  The Cheloninae, Macrocentrinae and Triaspinae seem to be exceptions to these generalizations, for they are internal parasitoids of hosts occurring in burrows or cavities in plant stems, fruits and seeds.  But these parasitoids oviposit either in the egg or the young larva attaining larval maturity in the fully grown host, so that the internal habit is necessary (Clausen 1940/1962).

 

Referring to adult habits, adults of most species are believed to feed mainly on honeydew and various plant exudations; but females of a large number subsist almost entirely upon the body fluids of the host stages that they attack.  Such habits occur generally in the subfamily Vipioninae and occasionally in the Microgasterinae.  It is well developed in the genus Microbracon and has been noted in almost all species that have been studied.  The host feeding habit was first observed by Trouvelot (1921) in M. gelechiae Ashm. (johannseni Vier.); and he and Genieys (1925) in the case of M. brevicornis Wesm., described the habit in some detail and gave an account of the formation of the feeding tube under the conditions that prevent normal direct feeding.  Genieys stated that ordinary laboratory food materials do not fulfill the nutritional requirements of the parasitoid female and that feeding on the body fluids of the host larva was essential before oviposition could take place. Chelonus shoshoeanorum Vier., was found to feed on the fluids that exude from the puncture in the egg of the host.  How the embryo survives and the hatched larva fairs after such an attack is worthy of investigation.

 

A large number of species are able to begin oviposition on the day of emergence of the female from the cocoon, although there is no uniformity here even within genera. Opius fulvicornis Thoms. is ready for immediate oviposition, while O. melleus Gahan requires a gestation period of circa 13 days. Apanteles melanoscelus ratz. (Crossman 1922) and Ascogaster quadridentata are able to oviposit soon after emergence.  Some species of Microbracon seem to require as much as 15 days.  Genieys noted an unusual condition in M. brevicornis, where unmated females began oviposition 4-5 days after emergence, but mated females required 14-18 days.  Some researchers defined the gestation period as the time elapsing between mating and first oviposition but, with the exception of the above instance, this has no bearing on the time at which the first eggs are laid as oogenesis proceeds whether or not mating has taken place.  In extended studies on the biology and habits of M. hebetor (= M. brevicornis), Hase (1922) observed that females can be successfully mated and produce female progeny even after 40 days, during which time male progeny are produced at the normal rate.  Oviposition is inhibited below 15°C (Clausen 1940/1962).

 

External braconid parasitoids usually attack host larvae that are half grown or larger which are contained in cells, leaf rolls, or burrows or are beneath a web or other covering.  Females of some species of Microbracon penetrate host burrows, attacking larvae directly. Bracon glaphyrus Mshll. burrows in the soil in search of Baris larvae, and Bracon sp. nr. hylobii, scrapes away the frass at the entrance of the burrow of Hylobius, turns about, and inserts the ovipositor into the burrow.  The female of Cardiochiles nigriceps Vier. straddles the young host larva and inserts the ovipositor by a downward thrust, while most other species of internal parasitoids oviposit by a forward thrust of the ovipositor between the legs.  In Apanteles, several earlier researchers insisted that oviposition was in the host egg, but this has not been proved (Clausen 1940/1962). A. militaris Walsh inserts the ovipositor in the body of the caterpillar and then folds its legs and retains its hold only by the ovipositor. A. glomeratus L. oviposits by preference in the newly hatched cabbage worms (Picard 1922).  In the attack by A. machaeralis Wlkn. of young caterpillars of Hapalia, the latter drop from the leaves and suspend themselves by a silken threat, whereupon the parasitoid quickly descends the thread and oviposits. Meteorus hypophloei Cush. attacks bark beetle larvae only when they are crawling about on the surface of the bark.  Among the Euphorinae, the species of Perilitus usually oviposit in the host beetles by inserting the ovipositor through the intersegmental membrane in the abdomen.  Several researchers believed that P. coccinellae oviposits in larvae and pupae as well as in the adult beetles, which has not been confirmed (Clausen 1940/1962). Microctonus melanopus Ruthe was noted by Speyer (1925) to insert the ovipositor through the anal opening of the host or the membrane nearby.  Females of Euphorus helopeltidis Ferr. jump on the back of the mirid nymph, curve their abdomen beneath the body and make the insertion in an abdominal suture or at the base of a coxa (Menzel 1926, 1929).  Females of Syrrhizus diabroticae Gahan, which oviposit in adult Diabrotica beetles, mount the back of the host, and the ovipositor is inserted dorsally at the base of the elytra. Cosmophorus henscheli Ruschka has a different habit, where the female attacks the host beetle head to head, grasps the back of the thorax between the mandibles and then brings the ovipositor forward and inserts it in one of the thoracic sutures.

 

Among endoparasitic and gregarious species, the full complement of eggs is usually deposited at one insertion of the ovipositor, and often very quickly.  Therefore, the female of Apanteles militaris deposits up to 72 eggs at one insertion in less than one second (Tower 1915).  However, Apanteles sagax Wlkn which develops in considerable numbers in the caterpillars of Sylepta derogata F., deposits eggs singly at some distance from each other (Wilkinson 1937).

 

Host larvae attacked by ectophagous braconids are usually permanently and completely paralyzed.  Once exception is Microbracon pini Mues., which inflicts only temporary paralysis, lasting ca. 1-hr, upon the larva of Pissodes strobi Peck. Bracon sp. attacking the larvae of Hylobius abietis L. does not sting the host, which are contained in burrows where they do not move very much during normal feeding (Munro 1917).  Donohoe (Clausen 1940/1962) found that some of the larvae of Ephestia figulilella Greg which have been stung by M. hebetor Say are able to effect complete recovery.  In the first 15 days of parasitoid activity, 12% of the hosts recovered, while 29% of those attacked during the third 15-day period recovered, showing a progressive lessening in effectiveness of the sting (Clausen 1940/1962).  Internal parasitoids seldom paralyze their hosts although larvae of bark beetles attacked by Coeloides dendroctoni Cush become inactive and appear paralyzed within two days after attack and are dead on the third day (De Leon 1935b).  Larval hosts of C. pissoidis are permanently paralyzed and sometimes killed by the sting.  Adult scolytid beetles attacked by Cosmophorus henscheli are paralyzed for one hour or more but recover completely.  Dipterous larvae parasitized by Alysia manducator are paralyzed for a period of 1-2 min, and recovery is accompanied by pronounced writhing movements.  Repetition of attack upon the same individual results in its death in one or two days, evidently from an excess of poison.

 

Among the groups that oviposit in the host egg, such as Ascogaster, Chelonus and Phanerotoma, the stage of development of the egg at the time of parasitoid oviposition has a notable influence on the extent to which attack is successful.  In A. quadridentata (= carpocapsae Vier.), Cox (1932) found that the female will oviposit in codling moth eggs in any stage of development, but parasitization is not successful if the "black-spot" stage has been reached.  Rosenberg (1934) secured successful parasitization even in that stage, however.  The egg is placed at random in the cytoplasm, but in such a position that it is always outside the host embryo when the latter becomes fully formed.  Entry into the body of the host embryo is accomplished by the newly hatched larva.  Vance (1932b) determined that females of C. annulipes Wesm. oviposit indiscriminately in corn borer eggs of any stage of development, but Wishart & Van Steenburgh (1934) showed that there is a marked difference in the number which attain maturity when oviposition takes place in those of different ages.  Maturity was reached by 26.6% of the parasitoid individuals when the host eggs were <24-h old, 36% in those which were 2.5 days old, and only 11.4% in those which were nearly ready to hatch.  In fresh eggs there is a good chance that the larva will be found outside the body of the embryo after it has developed, in which case no further growth can take place.  However, it may pass between the lateral folds before completion of the dorsal closure and become successful established. Eggs placed in the yolk after dorsal closure are a complete loss. After the embryo rotates, practically all eggs are placed within it.

 

In the Microgasterinae the only species known to oviposit in the host egg is Microgaster marginatus Nees, a parasitoid of Polia spp. in Russia (Zorin 1930).  The egg is laid in the host embryo 24h prior to hatching.  There are several parasitoids of Diptera among the Alysiinae which oviposit in host eggs bud do not attain larval maturity until the pupal stage.  Examples are Sympha agromyzae Roh. in Agromyza, Coelinidea meromyzae Forbes in Meromyza, and C. niger Nees in Chlorops (Clausen 1940/1962).

 

The gregarious external parasitoid of the larvae of Hapalia machaeralis Wlk and other Pyralidae in India (Beeson & Chatterjee 1935) and China (Chu 1935), Cedria paradoxa Wlkn. was the only braconid found demonstrating maternal care. The researchers emphasized the persistence of the female with the brood after the host was stung and the eggs laid, which care continued until the progeny attained the adult stage.  Another host may then be attacked, and the same events take place.  Chu believed that the females did not feed during this period.  A maximum of five broods was produced by each female, and the number of individuals in each brood decreased progressively.  The averages for a series of females producing four broods was 31.4, 20.3, 11.0 and 3.0 eggs in successive ovipositions.  Beeson & Chatterjee (1935) concluded that the total number of eggs deposited on a series of hosts was no greater than may normally be laid on a single one, and implied that a female normally attacks only one host individual during her lifetime.  They considered that the main purpose of brood care was for protection from attack by chalcidoid parasitoids. 
 

​

​

​

​