ICHNEUMONIDAE: : Mastrus Förster, 1869
Diagnosis:Characteristics of Mastrus include: 1. Body size <10mm; 2. Position of spiracle about 0.6x long Tergite 1 (behind the centre but not strongly); 3. Shape of aerolet in forewing pentagonal (open); 4. Colour of face all black; 5. Metasoma compressed dorsal-ventrally; 6. Size of ocelli small; 7. Length of antennae shorter than body; 8. Length of ovipositor distinct but not longer than the body; 9. Wings usually present; 10. Colour of wings hyaline (clear); 11. Sternaulus more than 0.5x length mesopleuron; 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 2; 16. Metasoma generally same colour throughout; 17. Length of T1 longer than T2; 18. Sculpture on mesoscutum finely pitted, but also glossy; 19. Width of T1 uniform, strongly widening from anterior to posterior; 20. Glymma on T1 absent; 21. Sculpture on metasoma smooth with a glossy appearance at least on T2; 22. Propodeum very short (not reaching beyond coxal insertion).
Distribution in NZ
North Island: HB.
Species in NZOne species, (Horstmann 2009), introduced in 2012 as a biological control agent for the codling moth Cydia pomonella (L.) (Lepidoptera: Tortricidae).
Biology & hostsMastrus ridens (originally identified as M. ridibundus) was collected from Kazakhstan in the 1990s. It was released in California, Argentina and Chile to control codling moth and brought into New Zealand quarantine in 2009 for tests to determine their behaviour, biology and ecological impacts (Sandanayaka et al. 2011). It was subsequently released into New Zealand 2012.
Sources of informationCharles JG, Dugdale JS. 2011. Non-target species selection for host-range testing of Mastrus ridens. New Zealand Entomologist 34: 45-51.
Sandanayaka WRM, Chhagan A, Page-Weir NEM, Charles JG. 2011. Colony optimisation of Mastrus ridens (Hymenoptera: Ichneumonidae), a potential biological control agent of codling moth in New Zealand. New Zealand Plant Protection 64: 227-234.
CitationWard DF & Schnitzler FR. 2013. Ichneumonidae of New Zealand. Genus Mastrus http://ichneumonidae.landcareresearch.co.nz
Accessed: 25 August 2019