Leschenaultia exul

(Townsend, 1892)

Leschenaultia exul is a tachinid fly that parasitizes tent caterpillars, particularly the forest (Malacosoma disstria) and eastern tent caterpillar (Malacosoma americana). Females locate using olfactory cues from larval and volatiles, combined with visual cues such as silk trails and larval aggregations. The deposits macrotype directly onto host larvae and is considered an important agent of forest tent caterpillar in North America.

Pronunciation

How to pronounce Leschenaultia exul: //lɛskəˈnaʊltiə ˈɛksʊl//

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Identification

As a tachinid fly, L. exul can be distinguished from other Diptera by the presence of prominent bristles on the body and the characteristic tachinid wing venation with a distinct bend in M. Specific identification to level requires examination of genitalic structures and comparison with . It may be distinguished from the congeneric Patelloa pachypyga, which also attacks forest , by differences in location and preference for aspen poplar versus balsam poplar host tree complexes.

Habitat

Forest supporting of tent caterpillars (Malacosoma ), particularly stands containing aspen poplar (Populus tremuloides) and balsam poplar (Populus balsamifera).

Distribution

North America; recorded from Canada and the United States. Specific study locations include Alberta, Canada.

Host Associations

Life Cycle

Females deposit macrotype directly onto larvae. Eggs hatch and larvae develop internally as , eventually killing the host. Specific details of and require further documentation.

Behavior

Females fly upwind toward and volatiles to locate hosts. They use visual cues including host silk trails and larval aggregations during host searching. In wind tunnel experiments, L. exul spent more time on the side containing volatiles from forest frass and showed preferential attraction to the forest tent caterpillar-aspen poplar complex over the forest tent caterpillar-balsam poplar complex.

Ecological Role

agent that contributes to of forest and eastern tent caterpillar. As a , it helps suppress of these defoliating forest pests.

Human Relevance

Contributes to natural of forest , a significant defoliator of hardwood forests in North America. May reduce the severity of and associated economic impacts on forestry and urban trees.

Similar Taxa

  • Patelloa pachypygaAlso a tachinid of forest ; can be distinguished by differences in location and tree preference, with P. pachypyga showing similar but not identical preferences for aspen poplar over balsam poplar

More Details

Host Location Mechanism

Research indicates L. exul uses a combination of olfactory and visual cues. Olfactory cues include produced by larvae and volatile compounds from host . Visual cues include the silk trails and aggregated larval masses characteristic of colonies.

Historical Taxonomy

Originally described as Blepharipeza exul by Townsend in 1892, later transferred to Leschenaultia. The 1936 study by W. R. Thompson in Annals of the Entomological Society of America established foundational biological knowledge of this .

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