Limits...
Thermoregulation of foraging honeybees on flowering plants: seasonal variability and influence of radiative heat gain.

Kovac H, Stabentheiner A - Ecol Entomol (2011)

Bottom Line: The thorax temperature excess decreased strongly with increasing T(a) (T(th)-T(a) = 21.6 - 3.6°C).3.An anova revealed that season had the greatest effect on T(th), followed by T(a) and radiation.4.It was presumed the foragers' motivational status to be the main factor responsible for the variation of T(th) between seasons and different plants.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, Karl-Franzens-University of Graz, Universitätsplatz 2 Graz, Austria.

ABSTRACT
1. During nectar and pollen foraging in a temperate climate, honeybees are exposed to a broad range of ambient temperatures, challenging their thermoregulatory ability. The body temperature that the bees exhibit results from endothermic heat production, exogenous heat gain from solar radiation, and heat loss. In addition to profitability of foraging, season was suggested to have a considerable influence on thermoregulation. To assess the relative importance of these factors, the thermoregulatory behaviour of foragers on 33 flowering plants in dependence on season and environmental factors was investigated.2. The bees (Apis mellifera carnica Pollman) were always endothermic. On average, the thorax surface temperature (T(th)) was regulated at a high and rather constant level over a broad range of ambient temperatures (T(th) = 33.7-35.7°C, T(a) = 10-27°C). However, at a certain T(a), T(th) showed a strong variation, depending on the plants from which the bees were foraging. At warmer conditions (T(a) = 27-32°C) the T(th) increased nearly linearly with T(a) to a maximal average level of 42.6 °C. The thorax temperature excess decreased strongly with increasing T(a) (T(th)-T(a) = 21.6 - 3.6°C).3. The bees used the heat gain from solar radiation to elevate the temperature excess of thorax, head, and abdomen. Seasonal dependance was reflected in a 2.7 °C higher mean T(th) in the spring than in the summer. An anova revealed that season had the greatest effect on T(th), followed by T(a) and radiation.4. It was presumed the foragers' motivational status to be the main factor responsible for the variation of T(th) between seasons and different plants.

No MeSH data available.


Related in: MedlinePlus

Temperature of the blossom surface near the honeybee mouthparts (means per flowering plant and day) in dependence on ambient temperature (Ta) at three different classes of solar radiation. Equations of linear regressions, number of observations, and regression statistics in Table 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3298660&req=5

fig04: Temperature of the blossom surface near the honeybee mouthparts (means per flowering plant and day) in dependence on ambient temperature (Ta) at three different classes of solar radiation. Equations of linear regressions, number of observations, and regression statistics in Table 2.

Mentions: The blossom surface temperature (range Tbl = 9.5–42.2°C) measured closely beside the bees' mouthparts increased linearly in dependence on Ta at all three categories of radiation (Fig. 4, Table 1, statistical details in Table 2). In sunshine the blossoms' temperature was about 4 °C elevated above the ambient air temperature. Under (partly) overcast skies (200–500 W m−2) the Tbl was also always higher than the ambient air temperature. However, the blossoms' temperature in shade was similar to the ambient air. The three regression lines differed significantly (anova, P < 0.0001, F-Ratio = 68.35, d.f. = 5), and the intercepts of values in sunshine versus the two other categories of radiation were also significantly different (P < 0.01; F-Ratio = 6.83, 9.53, 36.32; d.f. = 1).


Thermoregulation of foraging honeybees on flowering plants: seasonal variability and influence of radiative heat gain.

Kovac H, Stabentheiner A - Ecol Entomol (2011)

Temperature of the blossom surface near the honeybee mouthparts (means per flowering plant and day) in dependence on ambient temperature (Ta) at three different classes of solar radiation. Equations of linear regressions, number of observations, and regression statistics in Table 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3298660&req=5

fig04: Temperature of the blossom surface near the honeybee mouthparts (means per flowering plant and day) in dependence on ambient temperature (Ta) at three different classes of solar radiation. Equations of linear regressions, number of observations, and regression statistics in Table 2.
Mentions: The blossom surface temperature (range Tbl = 9.5–42.2°C) measured closely beside the bees' mouthparts increased linearly in dependence on Ta at all three categories of radiation (Fig. 4, Table 1, statistical details in Table 2). In sunshine the blossoms' temperature was about 4 °C elevated above the ambient air temperature. Under (partly) overcast skies (200–500 W m−2) the Tbl was also always higher than the ambient air temperature. However, the blossoms' temperature in shade was similar to the ambient air. The three regression lines differed significantly (anova, P < 0.0001, F-Ratio = 68.35, d.f. = 5), and the intercepts of values in sunshine versus the two other categories of radiation were also significantly different (P < 0.01; F-Ratio = 6.83, 9.53, 36.32; d.f. = 1).

Bottom Line: The thorax temperature excess decreased strongly with increasing T(a) (T(th)-T(a) = 21.6 - 3.6°C).3.An anova revealed that season had the greatest effect on T(th), followed by T(a) and radiation.4.It was presumed the foragers' motivational status to be the main factor responsible for the variation of T(th) between seasons and different plants.

View Article: PubMed Central - PubMed

Affiliation: Department of Zoology, Karl-Franzens-University of Graz, Universitätsplatz 2 Graz, Austria.

ABSTRACT
1. During nectar and pollen foraging in a temperate climate, honeybees are exposed to a broad range of ambient temperatures, challenging their thermoregulatory ability. The body temperature that the bees exhibit results from endothermic heat production, exogenous heat gain from solar radiation, and heat loss. In addition to profitability of foraging, season was suggested to have a considerable influence on thermoregulation. To assess the relative importance of these factors, the thermoregulatory behaviour of foragers on 33 flowering plants in dependence on season and environmental factors was investigated.2. The bees (Apis mellifera carnica Pollman) were always endothermic. On average, the thorax surface temperature (T(th)) was regulated at a high and rather constant level over a broad range of ambient temperatures (T(th) = 33.7-35.7°C, T(a) = 10-27°C). However, at a certain T(a), T(th) showed a strong variation, depending on the plants from which the bees were foraging. At warmer conditions (T(a) = 27-32°C) the T(th) increased nearly linearly with T(a) to a maximal average level of 42.6 °C. The thorax temperature excess decreased strongly with increasing T(a) (T(th)-T(a) = 21.6 - 3.6°C).3. The bees used the heat gain from solar radiation to elevate the temperature excess of thorax, head, and abdomen. Seasonal dependance was reflected in a 2.7 °C higher mean T(th) in the spring than in the summer. An anova revealed that season had the greatest effect on T(th), followed by T(a) and radiation.4. It was presumed the foragers' motivational status to be the main factor responsible for the variation of T(th) between seasons and different plants.

No MeSH data available.


Related in: MedlinePlus