Investigating termite nest thermodynamics using a quick-look method and the heat equation

Abstract

Termite mounds are often cited as an example of efficient thermoregulated structures. Nest thermal stability can be critical for insects that are particularly sensitive to heat and desiccation. Few studies have measured internal temperature of termite nests with respect to environmental parameters, especially in Neotropical species. In this study, we analyzed the thermal profiles of different parts of Procornitermes araujoi nests, a neotropical mound-building termite of the Brazilian cerrado. To read into our dataset we first used rasterization, a method that allows a quick-look assessment of time-series. Our results show that nest architecture efficiently buffers against environmental temperature fluctuations while at the same time maintaining a relatively high internal temperature in the core. This rather stable internal climate follows nevertheless the external temperature long-term averages. Using a novel numerical scheme, we further show that the heat transfer dynamics are well described by the classical heat equation, with an additional heat source whose origin is discussed.

Termites have developed wider thermal limits to cope with environmental conditions in savannas

“…Although we think it unlikely that there are mound thermoregulatory mechanisms in the Cubitermes species we sampled because of their very different thermal limits, our data are equivocal as to whether there is mound thermoregulation in Macrotermes bellicosus mounds. This is a topic of much debate (Korb, 2003;Jones and Oldroyd, 2006;Gouttefarde et al, 2017;Scott Turner, 1994;Turner, 2001). Macrotermes bellicosus had the same CTmax in all locations sampled despite environmental conditions varying among habitats; this suggests that there may be thermoregulatory mechanisms within their mounds, likely to maintain ideal growing conditions for their fungus symbionts (Korb and Linsenmair, 2000;Korb, 2003).…”

“…Termites have very different life history traits compared with other invertebrates (Poissonnier et al, 2018;Porter and Hawkins, 2001;Roisin, 2000); most termite species produce complex nest structures, and/ or live underground (Jones and Oldroyd, 2006;Noirot and Darlington, 2000). These subterranean environments could protect and buffer termites from extreme environmental conditions, maintaining stable and ideal nest conditions (Gouttefarde et al, 2017;Jones and Oldroyd, 2006;Korb, 2003). The adaptation of nest structures to provide more efficient thermoregulatory properties, such as altering the external shape to interact with the external temperature to maintain more stable internal conditions (Ocko et al, 2017;Singh et al, 2019;Vesala et al, 2019), may have helped enable forest termite species to colonise and prosper in savanna environments.…”

Termites have wider thermal limits to cope with environmental conditions in savannas

“…Although we think it extremely unlikely that there are mound thermoregulatory mechanisms in the Cubitermes-group species we sampled because of their very different thermal limits, our data are equivocal as to whether there is mound thermoregulation in Macrotermes bellicosus mounds. This is a topic of much debate (Korb, 2003;Jones & Oldroyd, 2006;Gouttefarde et al, 2017;Turner, 1994;Turner, 2001), because although large termite mounds can alter the internal temperature when compared with external air…”

“…Termites have very different life‐history traits compared with other invertebrates (Poissonnier et al, 2018; Porter & Hawkins, 2001; Roisin, 2000); most termite species produce complex nest structures, and/or live underground (Jones & Oldroyd, 2006; Noirot & Darlington, 2000). These subterranean environments could protect and buffer termites from extreme environmental conditions, maintaining stable and ideal nest conditions (Gouttefarde et al, 2017; Jones & Oldroyd, 2006; Korb, 2003). The adaptation of nest structures to provide more efficient regulatory properties, such as altering the external shape to interact with the external temperature to maintain more stable internal conditions (Ocko et al, 2017; Singh et al, 2019; Vesala et al, 2019), may have facilitated the colonisation and success of forest termite species in savanna environments.…”

“…Termites have very different life-history traits compared with other invertebrates (Poissonnier et al, 2018;Porter & Hawkins, 2001;Roisin, 2000); most termite species produce complex nest structures, and/or live underground (Jones & Oldroyd, 2006;Noirot & Darlington, 2000). These subterranean environments could protect and buffer termites from extreme environmental conditions, maintaining stable and ideal nest conditions (Gouttefarde et al, 2017;Jones & Oldroyd, 2006;Korb, 2003).…”