Trogus lapidator

(Fabricius, 1787)

Trogus lapidator is an ichneumonid that develops within the pupae of the Old World swallowtail Papilio machaon. It is notable for an unusual mechanism: rather than cutting through the pupal case with like most related wasps, it primarily uses a liquid secretion to soften and dissolve host tissue, employing mandibles only secondarily to spread the secretion and minimally enlarge the exit hole at the end of emergence. The occurs across Europe, with records from Finland to Belgium and Canada.

Trogus lapidator by (c) Tereshkin, some rights reserved (CC BY). Used under a CC-BY license.

Shaw et al 2015 Figs 1-4 (cropped) by Mark Robert Shaw, Pieter Kan, Brigitte Kan-van Limburg Stirum. Used under a CC BY 4.0 license.

Trogus lapidator by Tereshkin. Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Trogus lapidator: /ˈtroː.ɡus ˌla.pɪˈdaː.tor/

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Images

Distribution

Europe (including Finland, Belgium), with additional records from Canada (Alberta, British Columbia).

Host Associations

Papilio machaon - Develops within pupa; emerges from pupal stage, killing the host

Life Cycle

Development occurs within the pupa of its ; emerges from host pupa.

Behavior

Unusual mechanism: creates exit hole through pupal wing case primarily using a liquid secretion that softens and disintegrates host tissue. are used mainly to spread this secretion rather than to cut mechanically. Only at the very end of emergence are mandibles employed minimally to enlarge the hole. This contrasts with the typical cap-cutting emergence of most other Ichneumonidae from Lepidoptera pupae.

Ecological Role

of papilionid butterflies; regulator of Papilio machaon.