Natural Thermoelectric Heat Pump in Social Wasps

Ishay, Jacob S.; Pertsis, Vitaly; Rave, Eran; Goren, Alon; Bergman, David J.

doi:10.1103/physrevlett.90.218102

Cited by 21 publications

(25 citation statements)

References 10 publications

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“…We may note, in passing, that previously we have already detected and described another extracerebral organ in hornets, namely, the Ishay organ whose function, we posited, was to sense gravity (Ishay et al, 1996). The source of the heat energy in the TC is probably the conversion of voltage that derives from the hornet's cuticule, that is, thermovoltaic pulses that course along the length of its body (Ben-Shalom et al, 1988;Ben-Shalom and Ishay, 1989;Ishay et al, 1990;Ishay et al, 1991;Ishay et al, 1992), and the cooling is achieved via a thermoelectric heat pump (Ishay et al, 2003). Fig.…”

Section: Discussionmentioning

confidence: 99%

“…He concluded that the reason for this was that the hemolymph in both cases cools on its way from the thorax to the abdomen. We, too, have detected such distinct thermal differences in hornets between their gaster (gaster ¼ the last six segments of the abdomen in Hymenoptera), thorax, and even their head (Galushko et al, 2005;Ishay et al, 2003;Ishay et al, 2004). However, in all our examinations of hornets, but especially in the last-mentioned report, we have failed to find any clear-cut connection between the flow of hemolymph from the heart or aorta and the temperature of any part of the insect body.…”

Section: Introductionmentioning

confidence: 93%

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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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

A thermoregulatory center in hornets: IR photography

Plotkin

Ermakov

Volynchik

et al. 2005

Microsc. Res. Tech.

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“…In a previous study [10] we reported that in flying hornets the temperature is not uniform throughout the body, but rather the head and thorax are warm, whereas the gaster and legs are several degrees colder than the thorax (which is the warmest) and the head. The present investigation focused on the temperature distribution along the ventilating hornet's body, and an attempt is also made to explain the observed thermal differences between various body parts.…”

Section: Introductionmentioning

confidence: 83%

“…However, the body temperature of hornets leaving the nest for various tasks (e.g., foraging) changes, whether because the new ambient temperature exerts an effect on their own body temperature and/or because of the fact that in the course of these outside activities, part of their body (mainly the thorax) heats up while another part (mostly the gaster) cools down. We have recently reported [10] that the thorax of V. orientalis hornets flying out of the nest becomes warmer than the ambient temperature whereas the gaster gets colder, with the thermal difference between both ends of the body, in hornets returning to the nest after flight, amounting to about 7 • C. We assume that this temperature difference plays a very important role in communication between those members of the colony that stay at the nest entrance, always in light -as their different colors of their body is observed by the members arriving from outside of the nest; the colors displayed by these coming from the outside is different. The cuticle of the hornets is luminescent [17].…”

Section: Discussionmentioning

confidence: 99%

“…As pointed out in Ref. [10], the fact that the temperature in some parts of the hornet body is sometimes lower than ambient requires the employment of some active cooling mechanism by the hornet. The mechanism suggested there, namely thermoelectric heat pump operating across the thickness of the cuticle, could explain the appearance of such cooling effects, if certain physical parameters of the cuticle have appropriate values.…”

Section: Discussionmentioning

confidence: 99%

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Ventilating Hornets Display Differential Body Temperature

Ishay¹,

Plotkin²,

Ermakov³

et al. 2006

PIER

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Abstract-Our investigation entailed a thermal analysis of hornets engaging in ventilation activity at the nest entrance. In the hot summer months, between July-October, ventilating worker hornets are seen just outside the nest entrance, where they assume a typical stance, namely, with their feet erect and fastened to the substrate, their abdomen bent downward at a 90 • angle to the thorax, their antennae vibrating, and their wings beating rapidly for minutes at a time. Eventually these hornets leave their position, either to retreat into the nest or else to fly off to the field, and are replaced by new hornets that assume the ventilation task. Infra-red (IR) photography reveals that in the course of the ventilation activity, the warmest region in the ventilating hornet body is the anterior upper part of the thorax, and the coolest regions are the wings, limbs, antennae and abdomen. This study involved precise and repeated measurements via IR photography of the temperature in the various body parts of the ventilating hornets, and it also offers a preliminary, tentative explanation for the observed differential body temperature. The communication value of the color of the hornet body when ventilating is discussed.

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Presence of a thermoregulatory hot spot in the prothorax of the large carpenter bee and the bumble bee

Volynchik

Plotkin

Ermakov

et al. 2006

Microscopy Res & Technique

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In both the large carpenter bee (Xylocopa pubescens) and the bumblebee (Bombus terrestris), a hot spot was detected in the center of the prothorax on its dorsal-external aspect. In both cases, the temperature in this hot spot was found to be greater than the ambient temperature and that at the tip of the gaster. In B. terrestris, it was higher by 9-10 degrees C from that at the gaster tip and by 15-16 degrees C from the ambient temperature, while in X. pubescens the corresponding differences were 11-20 degrees C and 18-19 degrees C, respectively. The recorded thermal differences were not fixed but were rather variable, temporally as well as individually, but invariably all individuals measured showed these temperature differences. Furthermore, in none of the studied specimens was a hot spot detected in any part of the body other than the prothorax. From this hot spot in the prothorax, there is a cascade of temperatures in both directions, that is, anteriorly towards the head and posteriorly towards the gaster, with a graded drop in temperature in either direction. This article discusses possible reasons for the existence of such a hot spot in this particular location (the prothorax), its role or function, and its mode of operation. The authors speculate that it is a thermoregulatory center (for heating or cooling) that might be present in possibly all Hymenoptera that spend a considerable part of their life flying, regardless of whether they are social, parasocial, or solitary.

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Natural Thermoelectric Heat Pump in Social Wasps

Cited by 21 publications

References 10 publications

A thermoregulatory center in hornets: IR photography

A thermoregulatory center in hornets: IR photography

Ventilating Hornets Display Differential Body Temperature

Presence of a thermoregulatory hot spot in the prothorax of the large carpenter bee and the bumble bee

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