Ndlovu M, Pérez-Rodríguez A
Department of Zoology and Entomology, University of the Free State, P. O. Box 339, Bloemfontein 9300, South Africa.
Department of Zoology and Entomology, University of the Free State, P. O. Box 339, Bloemfontein 9300, South Africa.
J Therm Biol. 2018 May;74:23-28. doi: 10.1016/j.jtherbio.2018.03.004. Epub 2018 Mar 13.
Mound building termites are key ecosystem engineers of subtropical savanna regions. Mounds allow termites to maintain suitable conditions for termite reproduction and food cultivation ('fungus gardens'). We studied how the internal mound temperature of Macrotermes natalensis, a dominant mound-building termite of the subtropical savanna of southern Africa, responds to a number of environmental variables. We used general additive mixed models (GAMM) to determine how external temperature, mound size (volume) and the amount of vegetation shade affects mound internal temperature over a 24-h period. Internal mound temperature varied daily following changes of the external temperature, although the range of variation was much smaller. Active termite mounds maintained a higher internal temperature than inactive ones, and mound activity reinforced the positive effect of mound size and moderated the negative effect of vegetation shade on internal temperatures. In turn, external temperature fluctuations equally affected active and inactive mounds. Large mounds maintained near optimal internal temperatures compared to smaller sized mounds. We therefore conclude that termite mound size is a stronger determinant of internal mound temperature stability compared to plant shade cover.
筑丘白蚁是亚热带稀树草原地区关键的生态系统工程师。蚁丘能让白蚁维持适宜白蚁繁殖和食物培育（“菌圃”）的条件。我们研究了南非亚热带稀树草原优势筑丘白蚁纳塔尔大白蚁（Macrotermes natalensis）的蚁丘内部温度如何响应一系列环境变量。我们使用广义相加混合模型（GAMM）来确定外部温度、蚁丘大小（体积）和植被遮荫量在24小时内如何影响蚁丘内部温度。蚁丘内部温度随外部温度变化每日波动，尽管变化范围小得多。活跃的白蚁丘内部温度高于不活跃的蚁丘，蚁丘活动增强了蚁丘大小的积极影响，并缓和了植被遮荫对内部温度的负面影响。反过来，外部温度波动对活跃和不活跃蚁丘的影响相同。与较小的蚁丘相比，大型蚁丘能维持接近最佳的内部温度。因此，我们得出结论，与植物遮荫覆盖相比，白蚁丘大小是蚁丘内部温度稳定性更强的决定因素。
