Trieces

Townes, 1946

Species Guides

Trieces integer

Trieces is a of in the Ichneumonidae, Metopiinae. It is one of the largest genera within the Metopiinae, with described from all zoogeographical regions except the Indomalayan region until recently. Species are solitary endoparasitoids of Lepidoptera. The genus includes multiple species groups, with the onitis group being particularly well-studied in the Nearctic region.

Trieces by (c) Donald Hobern, some rights reserved (CC BY). Used under a CC-BY license.

Trieces diffidens by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Trieces: /ˈtriːsiːs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Trieces can be distinguished from its closest Chorinaeus by morphological characters detailed in identification keys. Members of the onitis group, which includes multiple Nearctic and Palearctic species, share characteristic features that allow grouping. Specific identification to species level requires examination of detailed morphological characters and reference to published keys for regional faunas.

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Habitat

Associated with deciduous forest in Canada, based on records for Nearctic of the onitis group.

Distribution

Recorded from Eurasia, Africa, North America, and the Neotropical region (including Brazil). Distribution records from GBIF include Denmark, Norway, and Sweden. Recent descriptions have extended the range to include India, representing the first records from the Indomalayan region.

Host Associations

Lepidoptera - All six of the onitis group with data in Canada are of deciduous forest Lepidoptera
Yponomeuta vigintipunctatus - for Trieces tricarinatus; competition with Triclistus yponomeutae observed in this host

Behavior

Solitary endoparasitoid development. In cases of multiparasitism, competition between larvae results in survival of only one individual. Physical aggression between first instar larvae has been observed as the mechanism of elimination.

Ecological Role

of Lepidoptera, contributing to of in forest .

Similar Taxa

ChorinaeusClosest to Trieces; can be separated using morphological characters detailed in published identification keys
TriclistusCo-occurring ichneumonid ; exhibits competitive interactions with Trieces in multiparasitized

More Details

Taxonomic history

established by Townes in 1946. The onitis group has been revised for the Nearctic region, with three previously described species redefined and six new species described. First records from the Indomalayan region were published in 2022 with three new species from India.

Competitive interactions

Studies of Trieces tricarinatus demonstrate that survival in multiparasitized depends on the relative timing of host and competitor hatching. T. tricarinatus survives only if host pupation occurs before egg hatching of the competing Triclistus yponomeutae.