A comparative survey of proboscis morphology and associated structures in fruit-piercing, tear-feeding, and blood-feeding moths in Calpinae (Lepidoptera: Erebidae)

Abstract

Functional feeding categories for adult species of Calpinae are described. Structures associated with the proboscis were examined using exemplar species in fruitpiercing, blood-feeding, and tear-feeding species using both light microscopy and SEM methods. At least three genera currently placed in Calpini, and several others in related groups lack specialized piercing structures. The proboscis of the tear-feeding species, Hemiceratoides hieroglyphica, is equipped with specialized cuticular hooks not yet observed in other tear-feeding species. Tearing hooks moveable by blood pressure are restricted to Calpini species, and little additional variation within this taxon exists, suggesting proboscis morphology may not be strongly correlated with feeding behavior (e.g., fruit piercing vs. blood feeding). A glossary of terms and character codings for proboscis structures is provided, and morphologies for all included calpine taxa are described.We discuss the taxonomic significance of proboscis morphology in Calpinae and the evolutionary implications of their associated feeding behaviors. This survey indicates morphology provides powerful prediction, but not proof of lepidopteran adult food habits.

Structure of the lepidopteran proboscis in relation to feeding guild

“…Studies of the lepidopteran proboscis have produced a mix of functional, structural, and positional terminology (Eastham and Eassa, ; Hepburn, ; Kingsolver and Daniel, ; Krenn, ; Walters et al, ; Krenn and Mühlberger, ; Krenn and Kristensen, ; Petr and Stewart, ; Zaspel et al, ; Monaenkova et al, ; Lehnert et al, ). We, therefore, explicitly define the terms that we use.…”

Blood, sweat, and tears: a review of the hematophagous, sudophagous, and lachryphagous Lepidoptera

“…This enables feeding while the bird is sleeping by holding its proboscis precisely between the eyelids. The proboscis morphology of H. hieroglyphica greatly resembles that of the blood feeders (Zaspel ). This species is actually in the same subfamily (Noctuidae: Calpinae) as the blood‐feeders, so it is more closely related to hematophagous moths than lachryphagous moths.…”

“…Proboscis of the blood‐feeding, skin‐piercing moth Calyptra eustrigata . eb erectile barbs, feb furcate erectile barbs, sc sensory cone, th tearing hooks (From Zaspel et al . Reprinted with permission from Zoomorphology).…”

“…Bänziger noticed that when he closed his eye during moth feeding, he would feel an “extremely sharp pain.” However, when his eye was open during feeding, he only felt “irritating stings of short duration” (Bänziger and Büttiker ). The extra pain associated with closed‐eye feeding might be the result of the shut eyelid making contact with minute triangular spines that on the surface of the L. griseifusa proboscis (Zaspel ). The threat of increased pain likely incentivizes hosts to keep their eyes open while L. griseifusa feeds; this increases the feeding surface area and enables greater numbers of moths to simultaneously feed on the same eye.…”

“…Hematophagous and lachryphagous Lepidoptera could potentially serve as vectors for disease, though this has never been documented (Bänziger , Hilgartner , Zaspel ). For successful biological transmission, a pathogen would most likely need to be in the vector's salivary gland, where it could multiply or change form and subsequently undergo transmission to the host via the vector's proboscis (Krenn and Aspock ).…”