Thermoregulation in the nests of hornets

Ishay, Jacob S.; Ruttner, F.

doi:10.1007/bf00300713

Cited by 49 publications

(33 citation statements)

References 12 publications

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“…However, they can be distinguished from each other by their abdominal respiratory pumping movements, which are discontinuous with long breaks in resting and sleeping bees ( Fig.·7A,B; Kaiser, 1988;Kaiser et al, 1996) but rapid and continuous in heating bees (Fig.·7C), implying high rates of respiration (Bailey, 1954;Fraenkel, 1932;Heinrich, 1972). Similar continuous and rapid respiratory movements have been described for various insects during warm-up before flight (Heinrich, 1993;Krogh and Zeuthen, 1941;Sotavalta, 1954) and for brood-incubating hornets (Vespa crabro; Ishay and Ruttner, 1971) and bumblebees (Bombus spp. ), where conspicuous differences in the abdominal pumping movements of resting and heating individuals also occur (Heinrich, 1972).…”

Section: Heating and Resting Beessupporting

confidence: 57%

Hot bees in empty broodnest cells: heating from within

Kleinhenz

Bujok

Fuchs

et al. 2003

Journal of Experimental Biology

165

139

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SUMMARY Honeybee colonies maintain brood nest temperatures of 33–36°C. We investigated brood nest thermoregulation at the level of individual worker behaviour and the transfer of heat from workers to the brood. Worker bees contribute to the regulation of brood nest temperature by producing heat while sitting motionless on the caps of brood cells. We report here an additional,newly observed heating strategy where heating bees enter empty cells between sealed brood cells and remain there motionless for periods of up to 45 min. Individually marked worker bees on the surface of sealed brood cells maintained thorax temperatures (Tth) between 32.2±1.0°C and 38.1±2.5°C (mean ± s.d.; N=20 bees) with alternating warming and cooling periods. Most of the observed bees made one or several long-duration visits(>2 min) to empty cells within the sealed brood area. Tth at the time bees entered a cell[Tth(entry)] was 34.1–42.5°C (N=40). In 83% of these cell visits, Tth(entry) was higher (up to 5.9°C; mean 2.5±1.5°C; N=33) than the mean Tth of the same bee. High values of Tth(entry) resulted from preceding heating activity on the comb surface and from warm-ups just prior to cell visits during which Tth increased by up to +9.6°C. Bees inside empty cells had mean Tth values of 32.7±0.1°C (resting bees) to 40.6±0.7°C (heat-producing bees) during long-duration cell visits without performing any visible work. Heating behaviour inside cells resembles heating behaviour on the brood cap surface in that the bees appear to be inactive, but repeated warmings and coolings occur and Tth does not fall below the optimum brood temperature. Bees staying still inside empty cells for several minutes have previously been considered to be `resting bees'. We find, however, that the heating bees can be distinguished from the resting bees not only by their higher body temperatures but also by the continuous, rapid respiratory movements of their abdomens. By contrast, abdominal pumping movements in resting bees are discontinuous and interrupted by long pauses. Heat transfer to the brood from individual bees on the comb surface and from bees inside empty cells was simulated under controlled conditions. Heating on the comb surface causes a strong superficial warming of the brood cap by up to 3°C within 30 min. Heat transfer is 1.9–2.6 times more efficient when the thorax is in touch with the brood cap than when it is not. Heating inside empty cells raises the brood temperature of adjacent cells by up to 2.5°C within 30 min. Heat flow through the comb was detectable up to three brood cells away from the heated thorax.

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Section: Heating and Resting Beessupporting

confidence: 57%

Hot bees in empty broodnest cells: heating from within

Kleinhenz

Bujok

Fuchs

et al. 2003

Journal of Experimental Biology

165

139

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“…Social wasps and hornets (Vespinae) are insects that retain a uniform temperature in their nest, namely, about (29 6 1)8C (Himmer, 1932;Ishay et al, 1967;Ishay and Ruttner, 1971). To cool the nest, the foraging worker hornets bring droplets of water to the nest, which they then attach to the silk caps of the larval cells.…”

Section: Introductionmentioning

confidence: 99%

A thermoregulatory center in hornets: IR photography

Plotkin

Ermakov

Volynchik

et al. 2005

Microsc. Res. Tech.

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In the Oriental hornet Vespa orientalis (Hymenoptera, Vespinae), there is on the dorsal side of the thorax, beneath the mesoscutum plate of the prothorax and around the median notal suture, a lump that, in the course of hornet activity, is warmer by 9 degrees C from the surrounding milieu and by up to 6 degrees C from other body parts of the hornet. This lump is about 1 mm in diameter, butterfly-shaped, and its upper, posterior border abuts the base of the forewings. During hornet activity and via Infra Red photography one can observe heat extensions stemming from the center of the lump and proceeding forward in the direction of the head, downward toward the legs and backwards toward the bases of the wings. The warmest region is the center of the lump, with its margins showing a lower temperature. As for the legs of the hornet, their upper part is warmer than the other parts. The temperature gradients along the hornet's body are dependent on the extent and nature of hornet activity. Thus, during flight or ventilation activity, the thorax is the warmest part of the body, while the wings, legs, and antennae, as well as the posterior part of the gaster are colder, yet all these body parts are still warmer to varying degrees than the surrounding milieu. Thus, at night, when sentry worker hornets stand guard around the nest entrance and remain practically motionless, the temperature differences between the various body parts are retained unchanged. We conjecture that the described butterfly-shaped lump is a thermoregulatory center (TC), which is neurogenically activated, since the changes occurring in it are rapid, a matter of one to several seconds and do not appear to be directly dependent on the hemolymph supply. The thermoregulatory center keeps a high constant temperature apparently related to hornet activity and the environmental conditions. The temperature cascade is most probably regulated via the tracheal system. Apparently another system activated by a heat pump mechanism keeps the gaster at a lower temperature than the environment.

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“…Hornet cuticle has a negative temperature coefficient (NTC) of the electrical resistivity, meaning that the resistivity decreases with increasing temperature up to optimal, following which there is an abrupt upsurge in the resistivity resulting in a positive temperature coefficient (PTC) of the resistivity (Xu, 1991). The ferroelectric properties of the hornet cuticle cease above the Curie temperature (Xu, 1991), which incidentally is also the optimal temperature in the hornet's nest, namely, around 298C (Ishay and Ruttner, 1971). Owing to the sharp transition that occurs when the cell roofs contain perovskite and the nest temperature exceeds the Curie (ferroelectric transition) temperature, the substance that was previously ferroelectric (in its tetragonal phase) now undergoes a transition to a rhombodedral phase (Van Aken et al, Fig.…”

Section: Discussionmentioning

confidence: 99%

Perovskites in the comb roof base of hornets: Their possible function

Ishay

Joseph

Galushko

et al. 2005

Microscopy Res & Technique

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On the ceiling of the Oriental hornet comb cell, there are mineral granules of polycrystalline material known to belong to the group of perovskites. In a comb cell intended to house a worker hornet, the roof base usually carries one or several such perovskite granules containing titanium (Ti), whereas in the roof base of a cell housing a developing queen, there are usually several granules containing a high percentage of silicon (Si), aluminum (Al), calcium (Ca), and iron (Fe), but very little if any Ti. In worker comb cells, Ti usually appears as ilmenite (FeTiO3). Besides documenting the above-mentioned facts, this report discusses possible reasons for the appearance of ilmenite crystals in worker cells only and not in queen cells.

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Thermoregulation in the nests of hornets

Cited by 49 publications

References 12 publications

Hot bees in empty broodnest cells: heating from within

Hot bees in empty broodnest cells: heating from within

A thermoregulatory center in hornets: IR photography

Perovskites in the comb roof base of hornets: Their possible function

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