Pachysomoides stupidus
(Cresson, 1874)
Pachysomoides stupidus is a gregarious ichneumon that parasitizes paper wasps (Polistes spp.). Females lay multiple on pre-pupal Polistes , and larvae feed gregariously as external on the pupa. The exhibits larval competition among siblings for resources, with males showing more altruistic than females in resource allocation. sex ratios are biased toward females, with investment ratios equalized by egg-layers.
Pronunciation
How to pronounce Pachysomoides stupidus: //ˌpækɪˈsoʊmɔɪdiːz ˈstjuːpɪdəs//
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Identification
Black and white banded body with orange legs. Distinguished from the Pachysomoides fulvus by geographic range and association details.
Distribution
Southeastern United States: North Carolina to Florida, Texas, and southern Illinois. Also recorded in Brazil (Rio de Janeiro, São Paulo) and Hawaii.
Host Associations
- Polistes - Pre-pupal and pupae; larvae feed gregariously as external on the pupa
Life Cycle
Females lay several on a pre-pupal Polistes . Larvae hatch and feed gregariously as external on the pupa. Up to 31 larvae have been observed on a single pupa. The larval paper wasp spins a silken cap over its before pupating, allowing parasitic larvae to feed undetected on the exterior of the nest. Gregarious development involves larval competition among siblings for host resources.
Behavior
Females oviposit on pre-pupal Polistes . Larvae exhibit gregarious feeding with sibling competition for resources. Males demonstrate more altruistic, less selfish behavior than females in resource competition contexts.
Ecological Role
of paper wasps (Polistes), regulating .
Similar Taxa
- Pachysomoides fulvusCongeneric ; P. fulvus ranges more broadly (New York to Florida, west to California and British Columbia) and lays on larvae or pupae inside nest rather than gregariously on pre-pupal