Trogus pennator

(Fabricius, 1793)

Trogus pennator is a in the Ichneumonidae that attacks larvae of swallowtail butterflies (Papilionidae), particularly in the Eurytides and Papilio. Females locate using chemical cues from larval and feeding damage. The is deterred from parasitizing Battus philenor due to aristolochic acid by that host. It has been recorded in North America including Vermont.

Trogus pennator by (c) Katja Schulz, some rights reserved (CC BY). Used under a CC-BY license.

Trogus pennator (27881686990) by Katja Schulz

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Trogus pennator (46970037271) by Christina Butler from Georgia, United States. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Trogus pennator: //ˈtroʊ.ɡəs pɛnˈneɪ.tɔr//

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

Identification

Trogus pennator can be distinguished from other Trogus by its associations and geographic distribution. Specific morphological diagnostic features are not documented in available sources.

Images

Habitat

Occurs in diverse where plants grow, including areas with plants in multiple used by Papilionidae as food sources.

Distribution

Recorded from North America, including Vermont, United States. The Trogus pennator argutus is recognized.

Host Associations

Eurytides (Papilionidae) - of larvaeConfirmed ; naive females innately respond to host and feeding damage cues
Papilio (Papilionidae) - of larvaeConfirmed ; includes P. machaon (Old World swallowtail)
Battus philenor - rejected Larvae are rejected due to chemical defense; aristolochic acids deter attack and offspring cannot survive

Behavior

Females exhibit innate preference for plants damaged by larvae over plants damaged by nonhost larvae, and prefer host extracts over nonhost frass extracts. Naive females show no innate preference for specific food plants but develop learned preferences after experience with hosts. Host-finding involves searching responses to frass and feeding damage cues.

Ecological Role

of larvae; contributes to of Papilionidae in the Eurytides and Papilio. Behavioral and physiological barriers prevent of chemically defended Battus philenor.

Similar Taxa

Other Trogus speciesShare similar lifestyle on swallowtail butterflies; distinguished by range and geographic distribution

More Details

Chemical Ecology

Aristolochic acids sequestered by Battus philenor larvae act as a behavioral deterrent to T. pennator females and create a physiological barrier preventing offspring survival, representing a multi-layered defense system.

Learning Behavior

T. pennator demonstrates flexible learning for plant cues (developed through experience) alongside fixed innate responses to -derived chemical cues (, feeding damage), indicating a dual mechanism for host location.