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Wing folding and unfolding in featherwing beetles (Coleoptera: Ptiliidae)тезисы доклада
- Авторы: Petrov P., Farisenkov S., Reshetnikova N., Polilov A.
- Сборник: Book of Abstracts of XXVI International Congress of Entomology (Helsinki, Finland, July 17-22, 2022)
- Тезисы
- Год издания: 2022
- Первая страница: 625
- Аннотация: Most adult beetles (Insecta: Coleoptera) are capable of folding their hindwings under the protective cover of the modified forewings (elytra) and unfolding them before flight. Beetles of the family Ptiliidae, which in most cases have a body length smaller than 1 mm and include the smallest free-living (non-parasitic) insects, are no exception: most ptiliids fly and are able to fold and unfold their bristled wings (a condition known as ptiloptery). This ability makes them unique among microinsects. The details of the two processes have been unclear, and the mechanics behind themremains almost a mystery. We have studied the wings, mechanisms of their folding and unfolding, and various structures involved in these mechanisms, in representatives of different groups of Ptiliidae, and the analyzed distribution of resilin in the wings of some species, using light, scanning electron, and confocal microscopy and high-speed video recording. Our results show that ptiliids have two different types of positioning the folded wings; the wings are folded using a complex mechanism involving several structures and unfolded largely by the elasticity provided by resilin. In the generally larger and less specialized basal genera, the wings are folded by bending along several diagonal lines and asymmetrically overlap at rest under the elytra, in a manner similar to Staphylinidae (Saito et al., 2014); in the other ptiliid genera, the wings are folded symmetrically, without overlapping, by bending at four points along lines subperpendicular to the axis of the wing. The setae, especially in the smaller, more advanced genera, are also folded, by bending at their bases, and lie subparallel to the wing blade. In the genus Ptenidium the wings have an additionalfifth bending line. The complex mechanism of folding and unfolding the feather-like wings involves several elements of the microsculpture of the elytra and different elements of the pterothoracic and abdominal dorsum, especially abdominal tergites. Remarkably, the wings of ptiliids contain only a single cavity, situated basally in the petiole and in the proximal portion of RA4 in the wing blade, and no cavities within any other veins. Therefore, the folding and unfolding of the wings largelydepend on the flexibility and resilience of the cuticle, and can only partly be guided by changes in the pressure of the haemolymph within the veins. The distribution of resilin in the wing is uneven: it is concentrated in the areas that bend during folding and unbend during unfolding. Resilin must also play a role in the flexibility of the wing during flight. In the studied ptiliids the wings inflight can bend at an amplitude of at least 17 degrees. Our results show that ptiliids have evolved a set of features that make their miniaturized wings easily foldable and unfoldable. These features may have contributed to the evolutionary success of ptiliids as the smallest free-living insects. The study was supported by the Russian Science Foundation (project no. 22-14-00028).
- Добавил в систему: Полилов Алексей Алексеевич