Uncovering head gland diversity in neotropical Polistinae wasps (Hymenoptera, Vespidae): Comparative analysis and description of new glands

Description of the Intramandibular Gland II in Polybia emaciata Lucas (Hymenoptera, Vespidae)

“…For our results to be more comparable with previous publications (Penagos-Arévalo et al, 2015) and because foragers are the caste involved in nest construction, foragers of Polybia emaciata were net-collected from Silvania, a farmland municipality in Cundinamarca, Colombia (4°24´19.7"N, 74° 22´30.9"W, 1475 m.a.s.l.). Wasps were delicately handled with soft forceps.…”

“…Wasps were delicately handled with soft forceps. Head section preparation followed standard protocols as described by Billen (1998), Samacá et al (2013) and Penagos-Arévalo et al (2015). Forager heads were sectioned after the posterior part of the vertex was removed and were immediately submerged in 2% glutaraldehyde in Na-cacodylate buffer for approximately 12 h at 4°C.…”

“…Gland description included the following: location, cell type according to the classification provided by Noirot and Quennedey (1974), maximum dorsoventral or anteroposterior extension, and cell diameter (Britto et al, 2004;Billen, 2009;Penagos-Arévalo et al, 2015).…”

“…Inside the mandibles of Neotropical social wasps, three glands have been identified, the intramandibular gland I, the intramandibular gland II, and the ectal mandibular gland (Penagos-Arévalo et al, 2015). The intramandibular gland I is a class 1 gland, whereas the other two are class 3 glands.…”

“…Cely-Ortiz observed this gland in Polybia emaciata in his unpublished undergraduate work (2011). However, in vespids, Penagos-Arévalo et al, (2015) provide the formal record of this gland. These authors recorded the gland in four of 33 species studied, and although P. emaciata was included in their extensive study, they did not report the intramandibular gland II in this species.…”