Colony composition and some costs and benefits of facultatively communal behavior in a Trinidadian webspinner (Embiidina: Clothodidae)

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Oxford University Press


lothoda urichi (Saussure), a Trinidadian webspinner, is facultatively communal; its colonies vary from solitary individuals to groups of reproductive females with their offspring sharing a silk covering. Communal females produce significantly more eggs than solitary females, but this increase is countered by significantly higher egg parasitism rates experienced by females reproducing under crowded conditions. C. urichi establishes colonies by remaining in its natal silk galleries, or by dispersing to establish a new gallery or to join an existing one. A model, developed by logistic regression analysis and based on the estimated area covered by silk, can be used to predict if a colony is solitary or communal, or whether half-grown nymphs are present.