Thoracic crop

Casadei-Ferreira, A., Fischer, G., Economo, E.P. 2020. Evidence for a thoracic crop in the workers of some Neotropical Pheidole species (Formicidae: Myrmicinae). Arthropod Structure, Development 59, 100977 (doi:10.1016/J.ASD.2020.100977)
 * Thoracic crop (see Petersen-Braun, M.; Buschinger, A. 1975: Entstehung und Funktion eines thorakalen Kropfes bei Formiciden-Königinnen. Insectes Sociaux 22: 51-66 (Development and function of a thoracic crop in ant queens);

During independent, claustral colony foundation of ant queens the flight muscles degenerate. The then „empty“ space within the thorax can be filled with a considerable swelling of the esophagus, which may serve as a „thoracic crop“, in addition to the usual crop in the gaster. Hölldobler & Wilson 1990, p.157: „More recently, it has been found that the esophagus of the queen expands into a "thoracic crop" in which the converted tissues are temporarily held in liquid form. In Pharaoh's ant (Monomorium pharaonis), the esophagus diameter widens from 7-10 micrometers to 265 micrometers. The thoracic crop has been demonstrated in five genera of Myrmicinae and Formicinae so far (Petersen-Braun and Buschinger, 1975).“