Apocrita

The Apocrita are a suborder of Hymenoptera insects, which includes the infraorder aculeata, that is the great majority of the Hymenoptera. The terebrantia, or parasitica, is considered a second infra-order of apocrites; they are a paraphyletic group, therefore invalid.

Anatomy description

Thoracic-abdominal region

The distinctive features of Apocrita reside in the morphological structure of the regions of the thorax and abdomen, markedly changed compared to the typical structure of the insect body:

  • the first abdominal segment (urite or uritis) contributes to forming the region of the thorax: assuming the physiognomy of a fourth thoracic segment, called propodeum, it is closely connected to the metathorax morphologically differentiated from the rest of the abdomen;
  • the abdomen is divided into two morphological regions: anteriorly the petiole, posteriorly the gastro. The petiole takes the form of a thin, more or less elongated peduncle, which connects the rest of the abdomen to the thorax. The II urite or II and III urites contribute to the formation of the petiole. Consequently, the apparent abdomen, the gastro, is formed by the remaining urites, starting from the III or IV.

In some Apocrites, belonging to the superfamily of the Chalcidoids, the petiole is rather reduced that the abdomen is apparently sessile. In all other Hymenoptera Apocrita the abdomen is visibly pedunculated and in some systematic groups the petiole reaches a considerable length.

The ovopositor

The other distinctive morphological characteristic of the Apocrites lies in the structure of the ovipositor. VIII and IX uritis contribute to the formation of this organ. Morphologically it is made up of two pairs of latero-ventral processes to which 3 pairs of processes called valvulae (sing. valvula), particularly developed in length are connected. The lateral processes are divided into two pairs of valvifers, formed respectively by the two urites. Two laminar expansions of quadrangular shape, called square laminae, are connected to the first pair of valvulae.

Valvulae are called first, second and third valvulae respectively. The first valvulae are merged to form a sheath in which the pair of second valvulae flows. The third valvulae, bristly and slightly sclerotic, forms a sort of elongated case that encloses the other valvulae. The first and second valvulae are strongly sclerotized and form an organ, called terebra, capable of sometimes penetrating particularly resistant plant tissues such as wood or the bark of trees, the cuticle of other insects, the epidermis of mammals.

Mouthparts

The mouthparts are chewing or chewing-lapping or chewing-sucking. In some systematic groups (Apoidea) the jaws completely lose their primitive function and are used for other purposes, such as work or transport organs, leaving the function of the intake of liquid foods to the ligula (second sucking or lapping mouthparts).

Apocrita have different diets. The adults can feed on sugary liquids, with a diet possibly supplemented by pollen, or they are carnivores, or omnivores. There are few phytophagous forms.

Extant families and superfamilies

Suborder Apocrita

  • (unranked) Aculeata
    • Superfamily Apoidea (bees and sphecoid wasps)
      • Family Ampulicidae (cockroach wasps)
      • Family Andrenidae (mining bees)
      • Family Apidae (carpenter bees, digger bees, cuckoo bees, bumble bees, orchid bees, stingless bees, and honeybees)
      • Family Colletidae (yellow-faced bees and plasterer bees)
      • Family Crabronidae (sand wasps, bee wolves, etc.)
      • Family Halictidae (“sweat bees”)
      • Family Heterogynaidae
      • Family Megachilidae (leaf-cutting bees)
      • Family Melittidae
      • Family Stenotritidae
      • Family Sphecidae (digger wasps)
    • Superfamily Chrysidoidea
      • Family Bethylidae
      • Family Chrysididae (cuckoo wasps)
      • Family Dryinidae
      • Family Embolemidae
      • Family Plumariidae
      • Family Sclerogibbidae
      • Family Scolebythidae
    • Superfamily Vespoidea
      • Family Bradynobaenidae
      • Family Mutillidae (velvet ants)
      • Family Pompilidae (spider wasps)
      • Family Rhopalosomatidae
      • Family Sapygidae
      • Family Scoliidae
      • Family Sierolomorphidae
      • Family Tiphiidae
      • Family Vespidae (paper wasps, potter wasps, hornets, pollen wasps, yellowjackets)
    • Superfamily Formicoidea
      • Family Formicidae (ants)
  • (unranked) Parasitica
    • Superfamily Ceraphronoidea
      • Family Ceraphronidae
      • Family Megaspilidae
    • Superfamily Chalcidoidea
      • Family Agaonidae (fig wasps)
      • Family Aphelinidae
      • Family Chalcididae (chalcid wasps)
      • Family Encyrtidae
      • Family Eucharitidae
      • Family Eulophidae
      • Family Eupelmidae
      • Family Eurytomidae (seed chalcids)
      • Family Leucospidae
      • Family Mymaridae (fairyflies) – the smallest of all insects
      • Family Ormyridae
      • Family Perilampidae
      • Family Pteromalidae
      • Family Rotoitidae
      • Family Signiphoridae
      • Family Tanaostigmatidae
      • Family Tetracampidae
      • Family Torymidae
      • Family Trichogrammatidae
    • Superfamily Cynipoidea
      • Family Austrocynipidae
      • Family Cynipidae (gall wasps)
      • Family Figitidae
      • Family Ibaliidae
      • Family Liopteridae
    • Superfamily Diaprioidea
      • Family Austroniidae
      • Family Diapriidae
      • Family Maamingidae
      • Family Monomachidae
    • Superfamily Evanioidea
      • Family Aulacidae
      • Family Evaniidae (ensign wasps)
      • Family Gasteruptiidae
    • Superfamily Ichneumonoidea
      • Family Braconidae
      • Family Ichneumonidae (ichneumon wasps)
    • Superfamily Megalyroidea
      • Family Megalyridae
    • Superfamily Mymarommatoidea – sometimes called Serphitoidea
      • Family Mymarommatidae
    • Superfamily Platygastroidea
      • Family Platygastridae
      • Family Scelionidae
    • Superfamily Proctotrupoidea
      • Family Heloridae
      • Family Pelecinidae
      • Family Peradeniidae
      • Family Proctorenyxidae
      • Family Proctotrupidae
      • Family Roproniidae
      • Family Vanhorniidae
    • Superfamily Stephanoidea
      • Family Stephanidae
    • Superfamily Trigonaloidea
      • Family Trigonalidae

References

  1. Apocrita. Wikipedia. https://en.wikipedia.org/wiki/Apocrita
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