Dusona leptogaster is a species of parasitic wasp belonging to the family Ichneumonidae, subfamily Campopleginae.

[1] It is a parasitoid of Geometrid moth larvae, the two known hosts being Alsophila aescularia and Lomaspilis marginata.

[3][4] Dusona leptogaster is a known parasitoid of two species of Geometrid moth: Alsophila aescularia and Lomaspilis marginata.

D. leptogaster larvae kill their host during its pupal stage and then spin a cocoon inside the now hollow pupa.

[2] Dusona leptogaster is known from most of the palearctic region: Austria, Azerbaijan, Belgium, Bulgaria, Croatia, Czech Republic, Finland, France, Germany, Hungary, Italy, Japan, Latvia, Moldova, Netherlands, Poland, Romania, Russia (including east Siberia), Sweden, Switzerland, Turkey, Ukraine and United Kingdom.