RT Journal Article
T1 Thermoregulatory function and sexual dimorphism of the throat sack in Helmeted Guineafowl (Numida meleagris) across Africa
A1 Van Niekerk, Johann H.
A1 Megia Palma, Rodrigo Manuel
A1 Forcina, Giovanni
AB The responses of ground-dwelling birds to heat and cold stress encompass a variety of behavioural, physiological and even morphological mechanisms. However, the role of glabrous skin in this respect has been marginally addressed so far. The Helmeted Guineafowl (Numida meleagris) is a landfowl distributed across Sub-Saharan Africa with eight traditionally recognised extant subspecies. Among the most prominent morphological traits underlying intraspecific variability are size and pigmentation of the bare throat skin (or sack), which might be related to the different habitats and environmental conditions across its wide range. In order to explore the Helmeted Guineafowl range-wide sack variation and pigmentation in relation to thermoregulation and sexual signalling, we collected morphometric and environmental information for N. m. coronata integrating field data with the inspection of photographic material encompassing seven subspecies and environmental information from their habitats. Field data evidenced that sack size was significantly correlated with ambient temperature, thus pointing to a likely involvement of the throat sack in thermoregulation. When the pictorial data from all subspecies were pooled, sack size correlated negatively with biomass, rainfall and humidity, while a positive correlation was found with annual solar irradiation. Sack size correlated positively with monthly temperature variation among the blue-throated subspecies from southern Africa as opposed to the black-throated subspecies ranging north to Zambia and Mozambique. Still, in this latter group the sack was often larger during winter months, possibly to maximise solar radiation absorbance. Noteworthy, sack size was related to sex dimorphism in two subspecies. Sack morphology and colour in the Helmeted Guineafowl likely modulate body temperature by evaporative cooling or heating upon needs, but in some subspecies it is also seemingly related to sexual signalling. Additional studies are needed to fully understand the multifunctionality of this important morphological feature in this species.
PB Elsevier
SN 2055-6187
YR 2022
FD 2022
LK https://hdl.handle.net/20.500.14352/113516
UL https://hdl.handle.net/20.500.14352/113516
LA eng
NO Van Niekerk, J. H., Megía-Palma, R., & Forcina, G. (2022). Thermoregulatory function and sexual dimorphism of the throat sack in Helmeted Guineafowl (Numida meleagris) across Africa. Avian Research, 13. https://doi.org/10.1016/J.AVRS.2022.100047
NO This work was funded by a research grant from the Percy Fitzpatrick Institute of African Ornithology, University of Cape Town, South Africa [REF. B 717]. Partial support was provided by the Portuguese Foundation for Science and Technology [FCT fellowships PTDC/BAA-AGR/28866/2017 and CEECIND/04084/2017] and the Spanish Government, Ministry of Universities (“María Zambrano” – Next Generation EU).
NO Percy FitzPatrick Institute of African Ornithology (Cape Town, South Africa)
NO Portuguese Foundation for Science and Technology
NO Ministerio de Universidades (España)
NO European Commission
DS Docta Complutense
RD 9 abr 2025