Thermoregulation strategies in ants in comparison to other social insects, with a focus on red wood ants (Formica rufa group)

Abstract

Temperature influences every aspect of ant biology, especially metabolic rate, growth and development. Maintenance of high inner nest temperature increases the rate of sexual brood development and thereby increases the colony fitness. Insect societies can achieve better thermoregulation than solitary insects due to the former’s ability to build large and elaborated nests and display complex behaviour. In ants and termites the upper part of the nest, the mound, often works as a solar collector and can also have an efficient ventilation system. Two thermoregulatory strategies could be applied. Firstly the ants use an increased thermal gradient available in the mound for brood relocation. Nurse workers move the brood according to the thermal gradients to ensure the ideal conditions for development. A precise perception of temperature and evolution of temperature preferences are needed to make the correct choices. A second thermoregulatory strategy used by mound nesting ants is keeping a high temperature inside large nests. The unique thermal and insulation properties of the nest material help to maintain stable conditions, which is the case of the Wood ant genus Formica. Ants can regulate thermal loss by moving nest aggregation and alternating nest ventilation. Metabolic heat produced by ant workers or associated micro organisms is an important additional source of heat which helps to maintain thermal homeostasis in the nest.

Diversity of fungi from the mound nests ofFormica ulkeiand adjacent non-nest soils

“…We also observed significant differences between the temperatures of the north and south sides of mounds (data not included), a phenomenon that can likely be attributed to variations in the dimensions of mounds, the composition and density of thatch, and degree of shading (Scherba 1962;Frouz 2000;Kadochová and Frouz 2014).…”

“…Nests are built in exposed sites and are oriented to maximize their exposure to solar radiation (Sherba 1958); they gain heat from solar radiation in the early spring and maintain temperatures that are higher and more stable than those of surrounding soils because of the insulating properties of thatch (Scherba 1962;Frouz and Jilková 2008). This layer of organic material prevents the overheating of mounds during the warmest parts of the year for other ant species that construct thatched nests (Bollazzi and Roces 2010;Kadochová and Frouz 2014) and it may serve the same function in F. ulkei.…”

The roles of microclimatic diversity and of behavior in mediating the responses of ectotherms to climate change

“…If they nonetheless approach their critical thermal maximum, they can climb onto small clods of sand or pebbles so that they push their bodies farther into cool overlying layers of air (Wehner et al, 1992). In the opposite direction from the surface, a highly predictable thermal gradient extends into the soil, and many organisms thermoregulate by moving vertically within the soil (Kadochová and Frouz, 2014). Local objects can also provide steep temperature gradients that can be exploited by slight repositioning of the body.…”

Taxonomic and functional ecology of montane ants

“…As a consequence, it is the assemblage patterns of these foraging workers that are of interest here. Colonies themselves, however, do have a suite of thermoregulatory mechanisms available to them (Kadochová and Frouz 2013). Unfortunately, colony-level community or demographic data are notoriously difficult, if not impossible, to obtain (but see Ingram et al 2013).…”