Saharan Silver Ant
Image: Norman Nan Shi and Nanfang Yu
Saharan silver ants, Cataglyphis bombycina, forage under conditions of extreme heat as an adaptation to avoid predators such as ant-eating lizards. Scout ants monitor the lizard activity. When the lizards take shelter from the heat, the scouts alert the ant foragers who venture outside the nest to forage without being attacked.
The surface temperature may reach 70 C, hot enough to fry and egg or damage proteins inside the cells. To prevent heat damage, the ants synthesize heat shock proteins before they venture out of the nest in anticipation of the high heat. The ants have long legs to elevate their bodies above the hot desert sand and into the cooler air of the boundary layer. The ants travel rapidly to minimize the exposure to the heat.
The ants have a silvery color due to triangular hairs that cover the body and shade the body from heat. The hairs reflect long wave visible and near infrared light, wavelengths with the most energy that would heat the ants. The reflected light gives them their silvery appearance. Not only do the hairs prevent heating by reflecting infrared waves, the hairs promote cooling by enhanced infrared emissions in mid range wavelengths. These emissions transfer heat from the warm surface of the ant to the cooler sky.
These adaptations (and probably others) allow silver ants to survive hostile environments. The cooling properties of their hairs may have potential use in cooling humans and our structures.
Norman Nan Shi & colleagues. Keeping cool: Enhanced optical reflection and radiative heat dissipation in Saharan silver ants. Science 17 Jul 2015: Â Vol. 349, Issue 6245, pp. 298-301
DOI: 10.1126/science.aab3564
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