An investigation of physiological adaptations for remarkable heat tolerance in a genus of desert-inhabiting African ants

Reading Time: 2 minutes

In their study in Myrmecological News, “Some like it hot: Physiological responses of hot-rod ants (Hymenoptera: Formicidae) and their interactions with past and future climate change”, Mbanyana et al. have provided the first study to elucidate physical and physiological adaptations of Ocymyrmex ants for activity for foraging on the ground at temperatures that would cause the great majority of ants to shrivel and die.

A Photoblog contribution by Nokuthula Mbanyana

Nokuthula Mbanyana

Edit by James Trager and Salvatore Brunetti

Hot-rod ants (Ocymyrmex fortior in the picture) climb up sticks or grass stalks to alleviate heat stress when foraging at high temperatures.

Ants within this group love sun exposure, and are extremely fast moving. They nest directly in soil on the ground and nests are sometimes found in the open or in rocky soils, usually with a crater of soil and small stones around the entrance.

Ocymyrmex ants typically nest in open, usually with a crater of soil around the entrance.

Hot rod ants (Ocymyrmex velox in the video) cleaning their nest entrances, and removing plant debris.

These arid-adapted ants are characterized by species with long legs that usually hold the head, thorax and gaster high above the substrate, which help with body temperature regulation.

Desiccation resistance is an essential trait for small organisms living in arid conditions. The cuticular lipids were extracted in the field from live Ocymyrmex ants , and cuticular hydrocarbon composition was analysed in the lab, given its role in cuticular waterproofing.

Critical thermal limits (CTmax and CTmin) were measured from selected Ocymyrmex species usimg a double-jacketed isolation chamber system connected to a programmable water bath.

Sampling for this study was conducted in arid and mesic regions of South Africa. In the picture, Nokuthula Mbanyana-Nhleko digging up an Ocymyrmex nest in Northern Cape (Leon Taaljard Nature Reserve), South Africa.

Some of the Ocymyrmex species are adapted to forage at ground temperatures exceeding 60ºC, and these ants are active during the hottest time of the day. Soil temperatures were measured before collecting ants.

Ocymyrmex ants feedig on a dead lizard. Photographed in Angola.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *