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A morphological query
As is well-known, in both insects and vertebrates, hairs create recurved plastrons, water-resistant surfaces. Among insects, they enable unwater mobility and breathing. Among theropods, feathers serve analogous functions of deflecting water from body surfaces, protecting the body from abrasions, and, on wings, they are boundary layers. In arthropods, macrochaetes (scales and bristles) are often innervated sense organs, fitting into sockets on the exoskeleton, and the bristles (longer, narrower scales) are ornamented on all sides, whereas scales (wide, flat macrochaetes) are asymmetrical and ornamented on only one side and not, in fact, found in several insect clades. Throughout the Mesozoic (as now), moths/butterflies were bright, colourful fliers (ultraviolet vision among feathered taxa and small pterosaurs enabling them to capture these prey), the colours and wing designs of the insect!
s due to an array of tapestried scales. And it is here, I pose a few questions for other colleagues on the DML (I am drawing from the insect work of Helen Ghiradella, who has provided me with much data and avenues of speculation).
The flying social insects (in the main, bees and Lepidoptera) pollinating radiating angiosperms, had macrochaetes functioning as communication devices, defense, aids in flight, feeding, and thermoregulation. Drawing from Helen's work, I ask if it is feasible that, among the small theropods emerging from China (I am intrigued by the undescribed "bristles" on the tail of a dinosaur specimen now in Europe, but await data), the feathers may have had homologous roles. Did feathers contain within them sensory mechanisms? Did they disperse scents and pheromones to attract insect prey?
As in Lepidoptera, feathered theropods had/have wings of various colour designs, useful for camouflage, communications in information centres (colonies). Among lepidopterans, e.g., the macrochaetes protect against spider webs and sundew plants (detaching and interfering with the "sundew", breaking webs), and one wonders if small theropods's feathers had similar roles. W. Nachtigall, in his 1974 Insects in flight, noted that macrochaetes are sound absorbers, protecting them from bats and some (?most) avian predators. Let us speculate: would the feathers of the small theropods have absorbed sound, protecting them from larger predators?