Chalcoela

Zeller, 1872

Sooty-winged Chalcoela (for C. iphitalis)

Species Guides

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Chalcoela is a of crambid ( Crambidae, Glaphyriinae) containing at least two described . The genus is notable for the parasitic of C. iphitalis, whose larvae are specialized of paper wasp (Polistes) larvae within their nests. This species represents a rare example of a lepidopteran that has evolved to exploit social hymenopteran colonies. The genus was established by Zeller in 1872.

Chalcoela iphitalis P1610953a by xpda. Used under a CC BY-SA 4.0 license.Chalcoela iphitalis P1610959a by xpda. Used under a CC BY-SA 4.0 license.Sooty-winged Chalcoela - Chalcoela iphitalis, Woodbridge, Virginia by Judy Gallagher. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Chalcoela: //kælˈkoʊ.lə//

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Identification

of C. iphitalis are small with sooty-dark wings. Caterpillars are strikingly similar in appearance to paper wasp larvae, an apparent case of mimicry that may facilitate their acceptance within nests. Webbing spun by caterpillars within wasp is a diagnostic clue to their presence.

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Habitat

Associated with paper wasp nests attached to sheltered substrates including eaves of buildings, palmetto leaves, wood, painted wood, metal, plastic, and cement. Nests built on twigs or branches appear to be avoided. Caterpillars overwinter inside abandoned nests.

Distribution

Eastern North America, with records from Vermont south to Florida and west to Kansas, Colorado, and Arizona. The has been introduced to Hawaii. Specific distribution varies by : C. iphitalis is widespread in eastern and central North America, while C. pegasalis distribution is less documented.

Seasonality

with in spring and late summer. occurs as larvae or pupae within abandoned nests.

Diet

Larvae of C. iphitalis are obligate of paper wasp pupae and pre-pupal stages. do not feed on ; larval diet is restricted to developing wasps within their .

Host Associations

Life Cycle

are laid singly on substrate surfaces adjacent to nests, not on nests directly. Eggs often deposited in clumps of seven or fewer when ovipositing females contact existing eggs. Larvae enter wasp and feed on pupae or pre-pupae, spinning silken cocoons with air pockets within cells. Developmental time approximately 4 weeks at 22°C. occurs within wasp cells. emerge in spring and late summer. Overwinters inside abandoned wasp nests.

Behavior

Oviposition occurs exclusively at night and is stimulated by contact with nests or wasps. remain motionless with tucked back during daytime. At night, moths fly and land near wasp nests with antennae fully extended and oscillating. Upon antennal contact with adult wasps, moths display avoidance by tucking antennae back and running rapidly in the opposite direction. Moths rarely walk directly on nest surfaces. Adult wasps exhibit alarm behavior upon detecting moths, including jerking movements, wing flipping, leaving the nest in pursuit, and alarming nestmates through vibrations; this response can persist for up to 10 hours.

Ecological Role

that can significantly impact paper wasp . Heavy are a documented primary cause of colony failure and nest decline in Polistes. The 's habit of in abandoned nests may contribute to the rarity of nest re-use by paper wasps. Serves as for the ichneumonid Calliephialtes grapholithae, linking paper wasp nests to this otherwise caterpillar-focused parasitoid.

Human Relevance

Occasionally encountered when paper wasp nests are removed from buildings. The 's oviposition and -mimic caterpillars make it a subject of interest for studies on - and mimicry. Heavy can contribute to wasp nest failure, potentially reducing nuisance wasp near human structures.

Similar Taxa

  • Other CrambidaeMany crambid are small and dark-winged, but Chalcoela is distinguished by its specialized association with paper wasp nests and oviposition . Most crambids are phytophagous, not predatory.

More Details

Parasitoid hyperparasitism

Chalcoela iphitalis serves as an intermediate linking the ichneumonid Calliephialtes grapholithae to paper wasp nests. This was previously known only from concealed caterpillar hosts (bagworms, leafrollers, etc.) and its from paper wasp nests was initially puzzling until the 's role was identified.

Host resistance

Field studies document differential among paper wasp . Mischocyttarus mexicanus shows complete resistance to despite sympatry with heavily infested Polistes . Possible mechanisms include chemical defenses from Van der Vecht's gland or behavioral differences in nest defense.

Research history

The of C. iphitalis was described in older literature, but critical details of oviposition and differential remained undocumented until a 2017 field and laboratory study in southern Louisiana.

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