ICHNEUMONIDAE: : Woldstedtius Carlson 1979
Diagnosis:Characteristics of Woldstedtius include: 1. Body size <10mm; 2. Position of spiracle on T1 at, close to, or before centre; 3. Shape of aerolet in forewing triangulate; 4. Colour of face not all black; 5. Metasoma compressed laterally (often very strongly in females); 6. Size of ocelli small; 7. Length of antennae shorter than body; 8. Length of ovipositor barely visible; 9. Wings present; 10. Colour of wings hyaline (clear); 11. Sternaulus absent; 12. Shape of face in lateral view flat or only weakly bulging; 13. Sternite on T1 (viewed laterally) not extending past spiracle; 14. Shape of T1 (viewed laterally) evenly curved; 15. Number of teeth in mandibles 3; 16. Metasoma same colour throughout or with colourful stripes; 17. Length of T1 vs T2 subequal in length; 18. Sculpture on mesoscutum finely pitted, many hairs; 19. Width of T1 (viewed dorsally) of uniform width (slightly widening posteriorly); 20. Glymma on T1 present, (deep pit); 21. Sculpture on metasoma smooth with a semi-glossy or satin appearance at least on T2; 22. Propodeum very short (not reaching beyond coxal insertion).
Similarity to Other TaxaIn two of the three species known, the metasoma is very strongly laterally compressed (knife-like) in females.
Although this can be hard to see, Woldstedtius has 3 teeth in the mandibles. The only other genus to have this in New Zealand is Diplazon . However, Diplazon has a distinct colouration on the hind tibia, whereas Woldstedtius have the same colour throughout.
Distribution in NZ
North Island: AK, WN. South Island: MB, DN, CO, OL, FD, SL.
Species in NZThree undescribed species.
Biology & hostsThis is a genus with a few species in the Neotropical and cooler areas of the Oriental region (Gauld 1984). Little is known about their biology in New Zealand, and no host records are known, although they are most likely to be parasitoids of hoverflys (Diptera: Syrphidae). Currently, there less than fifity specimens known in the NZAC, and the majority were collected from high elevations of >1000m.
Sources of informationGauld ID 1984. An Introduction to the Ichneumonidae of Australia. London, British Museum (Natural History). 413 p.
Ward DF. 2013. Diplazontinae (Hymenoptera: Ichneumonidae) from New Zealand. New Zealand Entomologist 36 (1): In Press.
Ward DF, Early JW, Schnitzler FR, Hitchmough RA, Stringer IAN. 2012. Conservation status of New Zealand Hymenoptera. New Zealand Entomologist 35 (2):116-119.
CitationWard DF & Schnitzler FR. 2013. Ichneumonidae of New Zealand. Genus Woldstedtius http://ichneumonidae.landcareresearch.co.nz
Accessed: 13 October 2019