Fedoseeva E.B. 2017. The metathoracic spiracles in some ants and wasps (Hymenoptera: Formicidae; Vespidae) // Russian Entomol. J. Vol.26. No.1: 49–62 [in English].

Zoological Museum of Lomonosov Moscow State University, Bolshaya Nikitskaya Street 2, 125009 Moscow, Russia.

key words: Aculeata, Comparative anatomy, mesosoma, mesopleuron, metapleuron, spiracular mechanism.

ABSTRACT. The second thoracic spiracle and the adjacent skeleton were studied in twenty-two ant species from nine Formicidae subfamilies (Formicinae, Dolichoderinae, Myrmeciinae, Paraponerinae, Ponerinae, Ectatomminae, Myrmicinae, Dorylinae and Ecitoninae) and two wasp species from Vespidae (Vespa crabro L., 1758 and Dolichovespula sp.). Dissections followed by scanning electron microscopy or photography revealed that the studied alate forms with concealed spiracles from both Aculeata families possess the spiracular occlusor muscle in addition to the supramesopleural sclerite concealing the true spiracle. There is assumed to be a homologous relationship between the re-discovered spiracular occlusor muscle of Aculeata and the corresponding muscle of the metathoracic spiracle in Symphyta. The comparison of winged Formicidae and ant workers with concealed spiracles demonstrated the similarities between them both on the position of plates covering the metathoracic spiracles (i.e. supramesopleural sclerite and spiracular lobe, respectively), and on the position of the spiracular occlusor muscles. Accordingly, the spiracular lobe of worker ants of Formicinae, Dolichoderinae, Myrmeciinae, Paraponerinae, Ponerinae and Ectatomminae was determined to be a derivative of the supramesopleural sclerite that is essential to their winged females. At the same time the exposed type of spiracles observed in studied Myrmicinae, Dorylinae and Ecitoninae ant workers corresponds with the absence of the supramesopleural sclerite in the alate forms.

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