Leptocybe invasa Fisher & La Salle

Eucalyptus gall wasp, Blue gum gall wasp

Hymenoptera: Chalcidoidea: Eulophidae: Tetrastichinae

Female: Color dark brown with metallic greenish / bluish tinge. Wings hyaline or lightly and uniformly infuscate. Antennal formula 11433 (anelli four-segmented). Mesoscutum without a median line. Scutellum with prominent submedian carinae. Dorsellum prominent, as long as propodeum. Fore wing with two setae on submarginal vein; postmarginal vein very short, only about a quarter as long as stigmal vein.

Male: Similar to female in general appearance and coloration; antennal formula 11343 with scape having a narrow and elongate sensory organ on lateral margin, annelli three-segmented, funicle four-segmented with long latero-terminal bristles and less stout than in female, club three-segmented; abdomen somewhat tubular. Doganlar (2005) described the males as follows: head and mesosoma brown with distinct blue to green metallic shine, metasoma brown with a slightly metallic tinge, legs pale yellow, except mid and hind coxae which have metallic shine, and antennae yellow. Males are fewer and not commonly observed as the wasp is mainly thelytokous. Doganlar (2005) provided a description of the male.

 Head
   Mesosoma, dorsal and lateral view
   Female antenna
 Male antenna
 Wing venation
   Adult female (left) and male (right) in profile

     Larva inside gall
     Pupa inside gall
     Freshly emerged adult
     Adult female
         Adult female - dorsal view
     Adult male - dorsal and lateral views

Middle East, the Mediterranean, Europe, Africa (Mendel et al., 2004); L. invasa is thought to originate from Australia, but its situation in this country is unknown. Presently recorded from Algeria, France (including Corsica), Israel, Italy, Jordan, Morocco, Portugal, Spain, Turkey, Algeria, Jordan, Kenya, Morocco, Syria, Tanzania, Uganda, Iran, Israel, Thailand, Turkey, Vietnam, and India (known so far from Andhra Pradesh; Delhi; Karnataka; Kerala; Uttar Pradesh; Tamil Nadu).

L. invasa attacks many Eucalyptus species (E. botryoides, E. bridgesiana, E. camaldulensis, E. globulus, E. gunii, E. grandis, E. saligna, E. maidenii, E. robusta, E. tereticornis, E. viminalis). The wasp causes typical bump-shaped galls on the leaf midribs, petioles, and stems of new growth of several Eucalyptus spp., particularly in young plantations and nurseries. Larvae form galls on the leaves and tender shoots of Eucalyptus spp. Heavy galling prevents further development of the infested growth. Mendel et al. (2004) described in detail the stages of gall formation and the biology of the wasp.

The wasp reproduces by thelytoky and only females have been known so far. Eggs are inserted in the epidermis of the upper side of newly developed leaves on both sides of the midrib, petiole and parenchyma tissue of twigs, always in a lined group. The section of the leaf midrib carrying the eggs turn from green to pink 1-2 weeks after oviposition. The galls are spherical and glossy green initially and later turn from green to light or dark red depending on whether the galls are on leaves or the stem. The emergence holes are light brown on the leaves and reddish brown on the stem (Mendel et al., 2004).

    Galls on seedlings
 Eucalyptus leaf with oviposition injury
   
     Galls on midribs of leaves
     Adult emergence holes on galls