Pales processioneae – the second OPM tachinid

Back in 2020 Andy Halstead got in touch with me to pass on some tachinids that he had reared in Surrey from tent webs of Oak Processionary Moth (Thaumetopoea processionea). A few of these were Carcelia iliaca, which was the first tachinid parasitoid to have been identified from UK OPM nests back in 2014.

Both species are specific parasitoids of OPM and it’s interesting that it took 6 years for P.processioneae to be found because in Europe Palese is by far the commonest parasitoid of OPM nests and C.iliaca is the rarer species.


With the arrival in 2020 of Pales processioneae this genus has gone from one which is very easily to identify to one which needs very careful examination when working in regions where OPM occurs.

  1. Males: cerci very narrow in dorsal view and very sinuous in lateral view. Surstyli with sharp bristlets on the outer face. Body quite weakly dusted and shiny. Face in both sexes 1.08 – 1.25x as long as the frons. 3rd antennal segment in males 3.5 – 4.6x, in females 2.5 – 3.0x as long as the 2nd. Frons in males 0.72 – 0.84x, in females 0.88 – 1.00x as wide as one eye…………….. pavida 
  • Males: cerci wider in dorsal view and quite straight in lateral view. Surstyli bare on the outer face. Body with denser dusting and hairier. Face in males 0.97 – 1.07x, in females 0.95 – 1.02x as long as the frons. 3rd antennal segment in males 3.0 – 3.7x, in females 2.4 – 2.8x as long as the 2nd. Frons in males 0.65 – 0.75x, in females 0.82 – 0.94x as wide as one eye……………… processioneae