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Termoregulace lesních mravenců r. Formica na výškovém gradientu
Kadochová, Štěpánka ; Frouz, Jan (advisor) ; Véle, Adam (referee)
This study examines thermoregulation behavior of wood ant genus Formica on elevation gradient. Two years long dataloger records of inner nest and ambient temperature were combined with detailed spring-summer manual measurement of nest temperature in different depths below nest surface. Results show that inner nest temperature was higher than air temperature in all seasons. Temperature of ant nest is highest in the deepest layer, the heat flows from inside out. We can assume that thermal homeostasis of ant nest in spring and summer i.e. in period of ant highest activity is influenced mainly by inner heat sources - microbial activity and ant metabolism. Insulation seems to have direct effect on nest temperature only in early spring; in summer insulation affects nest temperature indirectly, via ant activity. In winter there is pronounced effect of nest volume which corresponds high isolative properties of nest material. Our results indicate that thermoregulatory behavior of wood ants is driven by endogenous factors, namely colony needs in sense of queen oviposition brood development. Both of these require high temperature. Nests at variable altitude did not differ in average seasonal temperature or seasonal temperature fluctuation. Variability of nest temperature was bigger among nests from one...
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Wood ant thermoregulation heat cluster formation
Slováková, Jana ; Frouz, Jan (advisor) ; Kadochová, Štěpánka (referee)
This study focuses on the influence of ant clusters on nest thermoregulation. The significance of this influence has been measured using temperature information from dataloggers about inner nest as well as ambient air temperature during the period from April 4 to June 4, 2016 and images capturing the ant mound surface for the same period. The results show that the ant clusters incidence rate and the size of the clusters are significantly affected by the inner temperature of the nest. The dependence of the cluster occurrence on the inner temperature is not linear but rather has the character of steep drops at defined temperature thresholds. In the temperature range of 0 - 7řC cluster occurrence significantly increases and reaches the occurrence peak at the upper limit of this interval, from 7řC to 21řC the cluster occurrence rate is significantly lower but relatively constant and at the temperature above 21řC there is a steep decrease. The occurrence of clusters is also significantly determined by climatic influences and insolation, with the measured data showing that after a precipitation or snowfall, the average cluster size is significantly larger compared to similar days without a precipitation or snowfall recorded. Keywords: Formica polyctena, thermoregulation, nest, temperature, ecology
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Thermoregulation in ant genus Formica, an individual vs. colony conflict
Kadochová, Štěpánka ; Frouz, Jan (advisor) ; Dauber, Jens (referee) ; Domisch, Timo (referee)
This thesis deals with thermoregulation in red wood ants, in Formica rufa group. Our aim was to better understand the mechanisms by which red wood ants maintain thermal homeostasis in their nests. Red wood ants are known to keep high and stable temperatures in their nests from spring to autumn. Most emphasis is placed on the role of the nest mound as a solar collector or on a heat production by microbial community present in the nest material. However, some researchers believe that wood ants are able of active nest thermoregulation in which they can affect the nest temperature by behavioural reactions, mainly by sun basking, increased metabolic heat production or heat transport. The thesis consists of three research articles. The first one is focused on the timing of thermoregulation in red wood ants, the second one investigates in more detail one specific aspect of red wood ant thermoregulation - a sun basking behaviour. These two papers provide data from long-term field observations and experiments. The last paper is based on laboratory experiments where we tested a hypothesis resulting from field observations. Thanks to the field research we found out that ant activity (traffic on ant trails) significantly correlates with nest temperature; once the activity decreased the thermal homeostasis...
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Termoregulace lesních mravenců r. Formica na výškovém gradientu
Kadochová, Štěpánka ; Frouz, Jan (advisor) ; Véle, Adam (referee)
This study examines thermoregulation behavior of wood ant genus Formica on elevation gradient. Two years long dataloger records of inner nest and ambient temperature were combined with detailed spring-summer manual measurement of nest temperature in different depths below nest surface. Results show that inner nest temperature was higher than air temperature in all seasons. Temperature of ant nest is highest in the deepest layer, the heat flows from inside out. We can assume that thermal homeostasis of ant nest in spring and summer i.e. in period of ant highest activity is influenced mainly by inner heat sources - microbial activity and ant metabolism. Insulation seems to have direct effect on nest temperature only in early spring; in summer insulation affects nest temperature indirectly, via ant activity. In winter there is pronounced effect of nest volume which corresponds high isolative properties of nest material. Our results indicate that thermoregulatory behavior of wood ants is driven by endogenous factors, namely colony needs in sense of queen oviposition brood development. Both of these require high temperature. Nests at variable altitude did not differ in average seasonal temperature or seasonal temperature fluctuation. Variability of nest temperature was bigger among nests from one...
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