Activation of the Fibrillar Muscles in the Bumblebee During Warm-Up, Stabilization of Thoracic Temperature and Flight

1973 ◽  
Vol 58 (3) ◽  
pp. 677-688
Author(s):  
BERND HEINRICH ◽  
ANN E. KAMMER
Keyword(s):  
Heat Production ◽  
Action Potentials ◽  
Spike Frequency ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Heating And Cooling ◽  
Thoracic Temperature ◽  
Flight Muscles ◽  
Frequency Of Action Potentials ◽  
Physical Laws

1. Extracellular action potentials and thoracic temperatures (TTh) were simultaneously recorded from the fibrillar flight muscles of Bombus vosnesenskii queens during preflight warm-up, during stabilization of TTh in stationary bees, and during fixed flight. 2. In most stationary bees during warm-up and during the stabilization of TTh the rate of heat production, as calculated from thoracic temperature and passive rates of cooling, is directly related to the frequency of action potentials in the muscles. 3. The rate of heat production increases throughout warm-up primarily because of a greater spike frequency at higher TTh. 4. In stationary bees during the stabilization of TTh at different ambient temperatures (TA) the fibrillar muscles are activated by any in a continuous range of spike frequencies, rather than only by on-off responses. 5. Regulation of TTh in stationary bees may involve not only changes in the rate of heat production but also variations of heat transfer from the thorax to the abdomen. 6. During fixed flight the fibrillar muscles are usually activated at greater rates at the initiation of flight than later in flight, but the spike frequency and thus heat production are not varied in response to differences in TA and heating and cooling rates. 7. During fixed flight TTh is not regulated at specific set-points; TTh appears to vary passively in accordance with the physical laws of heating and cooling. 8. Differences in the TTh of bees in free and in fixed flight are discussed with regard to mechanisms of thermoregulation.

An Analysis of Pre-Flight Warm-Up in the Sphinx Moth, Manduca Sexta

1971 ◽  
Vol 55 (1) ◽  
pp. 223-239 ◽  
Author(s):  
BERND HEINRICH ◽  
GEORGE A. BARTHOLOMEW
Keyword(s):  
Ambient Temperature ◽  
Manduca Sexta ◽  
Heat Production ◽  
Blood Circulation ◽  
Cardiac Activity ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature ◽  
Wing Vibration ◽  
Rate Of Increase

The physiology of pre-flight warm-up in Manduca sexta was analysed with regard to rate of heat production, regional partitioning of heat between thorax and abdomen, and the control of blood circulation. 1. When moths which have come to equilibrium with ambient temperature undergo pre-flight warm-up, the thoracic temperature increases linearly until flight temperature (37-39 °C) is approached. 2. The rate of increase in thoracic temperature during warm-up increases directly with ambient temperature from about 2 °C/min at 15 °C to about 7.6 °C/min at 30 °C. 3. The temperature of the abdomen remains near ambient throughout the period of warm-up, but during the initial part of post-flight cooling while thoracic temperature declines sharply abdominal temperatures rise appreciably. 4. During warm-up the rate of wing vibration increases linearly with thoracic temperature. At a thoracic temperature of 15 °C the rate is about 8/sec and at 35 °C it is about 25/sec. 5. When resting animals are held by the legs they at once begin to beat their wings through a wide angle. These wing beats at any given thoracic temperature are slower than the wing vibrations characteristic of normal warm-up, but they cause thoracic temperature to increase at almost the normal rate. 6. The removal of thoracic scales causes a decrease in rate of warm-up, but in still air this does not prevent the moths from reaching flight temperature. 7. During cooling the rate of decrease in thoracic temperature is greater in live animals than in freshly killed ones. At any given difference between thoracic and ambient temperatures cooling rates are directly related to thoracic temperature. 8. In resting moths heart pulsations are usually variable with regard to rate, amplitude, rhythm, and sometimes direction, but the records of cardiac activity simultaneously obtained from thorax and abdomen show close correspondence. 9. During warm-up the records of changes in impedance from electrodes in the abdomen indicate that pulsations of the abdominal heart are either absent, greatly reduced, or at a frequency different from that simultaneously recorded from the thorax. 10. The calculated rate of heat production during warm-up is linearly related to thoracic temperature. 11. Our data are consistent with the assumption that heat produced in the thorax during warm-up is sequestered there by reduction in blood circulation between thorax and abdomen. 12. Rates of warm-up in insects are close to the values predicted on the basis of body weight from data on heterothermic birds and animals.

Flight Energetics and Heat Exchange of Gypsy Moths in Relation to Air Temperature

1980 ◽  
Vol 88 (1) ◽  
pp. 133-146
Author(s):  
TIMOTHY M. CASEY
Keyword(s):  
Air Temperature ◽  
Heat Production ◽  
Beat Frequency ◽  
Warm Up ◽  
Heating And Cooling ◽  
Thoracic Temperature ◽  
Air Temperatures ◽  
Respiratory Heat Loss ◽  
Flight Morphology ◽  
Gypsy Moths

Gypsy moths elevate thoracic temperature (Tth) during flight by endogenous heat production but do not regulate it. Thoracic temperature of moths in free, near-hovering flights exceeded air temperature by approximately 6–7 °C at all Tα's between 17 and 32 °C. Mean rates of mass specific oxygen consumption varied between 40 and 47 ml O2 (g·h)−1 and were not correlated with air temperature. Wing-beat frequency increased from 27 to 33 (s)−1 between air temperatures of 18 and 35 °C. Thoracic heating and cooling constants are similar in live and dead moths, and removal of thoracic scales increases heating constants by about 12%. Preflight warm-up occurs at low Tα's but the moths are capable of immediate, controlled flight at Tα's above 22 °C. Relatively low levels of heat production by the flight muscles are a consequence of low power requirements associated with the flight morphology of gypsy moths. Calculated rates of thoracic and respiratory heat loss of free-flying moths are slightly lower than values of heat production.

Effects of Ambient Temperature on Warm-Up in the Moth Hyalophora Cecropia

1973 ◽  
Vol 58 (2) ◽  
pp. 503-507
Author(s):  
GEORGE A. BARTHOLOMEW ◽  
TIMOTHY M. CASEY
Keyword(s):  
Ambient Temperature ◽  
Heat Production ◽  
Cooling Curves ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Logarithmic Plot ◽  
Thoracic Temperature ◽  
Hyalophora Cecropia ◽  
The Difference ◽  
Straight Lines

The rates of pre-flight warm-up in adult Hyalophora cecropia (mean weight 3.10g) were measured 24-36 h after eclosion at 15, 20, 25, and 30 °C in still air. 1. The rate of thoracic warm-up increased linearly with ambient temperature, averaging 2.6 °C/min at 15 °C and 6.5 °C/min at 30 °C. 2. Thoracic temperatures typically reached 37-39 °C while abdominal temperatures rarely rose more than 3 °C above ambient. 3. The cooling curves of the thorax at 15° and 25 °C were straight lines and had similar slopes on a semi-logarithmic plot. 4. Our data are compatible with the idea that heat production is dependent on thoracic temperature, and are incompatible with the theory that it depends on the difference between thoracic and ambient temperatures.

Thermoregulation in Small Flies (Syrphus Sp.): Basking and Shivering

1975 ◽  
Vol 62 (3) ◽  
pp. 599-610
Author(s):  
BERND HEINRICH ◽  
CURT PANTLE
Keyword(s):  
Air Temperature ◽  
Beat Frequency ◽  
Vibration Frequencies ◽  
Wing Beat ◽  
Hovering Flight ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature ◽  
Flight Muscles ◽  
Vibration Rate

1. Flies of the genus Syrphus aggregated at specific sites in the field (‘lecks’). Flies at leeks were always capable of ‘instant’ take-of, even at ambient temperatures of 10 °C or less. 2. The flies regulated their thoracic temperature by a combination of basking and shivering. During hovering flight in sunshine thoracic temperature rose 12–14 °C above the ambient temperature. 3. The flies engaged in frequent brief chases while at the lecks. 4. At an air temperature > 18 °C the flies at the leck remained in hovering flight most of the time. 5. The vibration frequencies of the thorax during shivering and flight ranged from about 100 to 200 Hz at 10–27 °C, though at a given temperature and spike frequency the vibration rate during warm-up was higher than the wing-beat frequency (assumed to be the same as thoracic vibration frequency) during flight. 6. During shivering, but not in flight, there is a tendency for the indirect flight muscles to be activated in synchrony.

Thermoregulation of African and European Honeybees during Foraging, Attack, and Hive Exits and Returns

1979 ◽  
Vol 80 (1) ◽  
pp. 217-229 ◽  
Author(s):  
HEINRICH BERND
Keyword(s):  
Metabolic Rate ◽  
Ambient Temperature ◽  
Heat Loss ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature

1. While foraging, attacking, or leaving or returning to their hives, both the African and European honeybees maintained their thoracic temperature at 30 °C or above, independent of ambient temperature from 7 to 23 °C (in shade). 2. Thoracic temperatures were not significantly different between African and European bees. 3. Thoracic temperatures were significantly different during different activities. Average thoracic temperatures (at ambient temperatures of 8–23 °C) were lowest (30 °C) in bees turning to the hive. They were 31–32 °C during foraging, and 36–38 °C in bees leaving the hive, and in those attacking. The bees thus warm up above their temperature in the hive (32 °C) before leaving the colony. 4. In the laboratory the bees (European) did not maintain the minimum thoracic temperature for continuous flight (27 °C) at 10 °C. When forced to remain in continuous flight for at least 2 min, thoracic temperature averaged 15 °C above ambient temperature from 15 to 25 °C, and was regulated only at high ambient temperatures (30–40 °C). 5. At ambient temperatures > 25 °C, the bees heated up during return to the hive, attack and foraging above the thoracic temperatures they regulated at low ambient temperatures to near the temperatures they regulated during continuous flight. 6. In both African and European bees, attack behaviour and high thoracic temperature are correlated. 7. The data suggest that the bees regulate thoracic temperature by both behavioural and physiological means. It can be inferred that the African bees have a higher metabolic rate than the European, but their smaller size, which facilitates more rapid heat loss, results in similar thoracic temperatures.

Contribution of shivering in leg muscles to heat production in Japanese quail

1986 ◽  
Vol 64 (4) ◽  
pp. 889-892 ◽  
Author(s):  
E. Don Stevens ◽  
J. Ferguson ◽  
V. G. Thomas ◽  
E. Hohtola
Keyword(s):  
Ambient Temperature ◽  
Japanese Quail ◽  
Heat Production ◽  
Open Circuit ◽  
Linear Rate ◽  
Ambient Temperatures ◽  
Coturnix Coturnix ◽  
Metabolic Heat ◽  
Leg Muscles ◽  
Flight Muscles

We estimated heat production in Japanese quail (Coturnix coturnix japonica) by measuring oxygen uptake using open-circuit respirometry as ambient temperature was decreased gradually from 26 to 3.5 °C. At the same time, the intensity of shivering was estimated in both the leg muscles and the flight muscles by measuring electromyograms. Metabolic heat production increased in a linear fashion as ambient temperature decreased. Shivering intensity increased at the same linear rate in the leg muscles as in the flight muscles as ambient temperature decreased. The leg muscles produce a substantial fraction (about 1/4) of the total shivering heat production at low ambient temperatures. Shivering occurred in bursts; the onset of a burst in the leg muscles was precisely synchronized with the onset of a burst in the flight muscles.

Carbohydrate Use in the Flight Muscles of Manduca Sexta During Pre-Flight Warm-Up

1987 ◽  
Vol 133 (1) ◽  
pp. 317-327 ◽  
Author(s):  
BARBARA JOOS
Keyword(s):  
Manduca Sexta ◽  
Glycogen Content ◽  
Agricultural Experiment Station ◽  
Warm Up ◽  
Total Cost ◽  
Ambient Temperatures ◽  
Budget Analysis ◽  
Rutgers University ◽  
Agricultural Experiment ◽  
Flight Muscles

Although fat is the principal fuel for flight in moths and butterflies, some use of carbohydrate fuels during activity would be predicted on energetic and biochemical grounds, particularly in nectivores. The present study evaluates the use of carbohydrate fuels during pre-flight warm-up in the endothermic sphinx moth Manduca sexta (L.). Carbohydrate content of moths was measured at intermediate points during the pre-flight warm-up cycle and at take-off. Muscle glycogen content declined during the initial phases of warm-up, whereas glucose and trehalose concentrations were unchanged. Abdominal carbohydrates were not mobilized during warm-up. Energy budget analysis suggests that glycogen oxidation supplies about 39% of the energy needed for the initial phase of warm-up and about 6% of the total cost of warm-up. Glycogen use during warm-up may be correlated with the capacity for endothermic warm-up at low ambient temperatures. Carbohydrates appear to be more important as fuels for activity in some lepidopterans than has been previously reported for other members of this diverse Order. Note: Present address: Department of Entomology and Economic Zoology, New Jersey Agricultural Experiment Station, Cook College, Rutgers University, New Brunswick, NJ 08903, USA.

Physiology and Energetics of Pre-Flight Warm-Up in the Eastern Tent Caterpillar Moth Malacosoma Americanum

1981 ◽  
Vol 94 (1) ◽  
pp. 119-135
Author(s):  
TIMOTHY M. CASEY ◽  
JERI R. HEGEL ◽  
CHARLENE S. BUSER
Keyword(s):  
Heat Production ◽  
Stroke Work ◽  
Stroke Frequency ◽  
Warm Up ◽  
Thoracic Temperature ◽  
Air Temperatures ◽  
Tethered Flight ◽  
Tightly Coupled ◽  
Head Temperature ◽  
Tent Caterpillar

Thoracic temperature (Tth) during pre-flight warm-up increased linearly with time at all air temperatures (Ta). The rate of pre-flight warm-up increased from 3.3 to 12.7 °C/min between Ta's of 14 and 28 °C. Head temperature remained within a few °C of Tth during warm-up, while ventral abdominal temperature remained within a few °C of Ta. Pulsation rate of the dorsal vessel in the thorax increased directly with thoracic temperature. Wing-stroke frequency (n) varied from 15 s−1Tth = 16 °C to 58 s−1 at Tth = 40 °C and was similar at any given Tth between Ta's of 14 and 28 °C. While stroke amplitude varied significantly between warm-up and tethered flight, stroke frequency was similar for the two activities in the same Tth range. Calculated rates of heat production were tightly coupled to Tth and did not vary with Ta. The change in heat production during warm-up was dependent entirely on changes in frequency of muscle contraction. Stroke work was constant at 0.68 mW between Tth of 15 and 40 °C.

scholarly journals Female pheromones modulate flight muscle activation patterns during preflight warm-up

2013 ◽  
Vol 110 (4) ◽  
pp. 862-871 ◽  
Author(s):  
José G. Crespo ◽  
Neil J. Vickers ◽  
Franz Goller
Keyword(s):  
Muscle Contraction ◽  
Heating Rate ◽  
Heat Production ◽  
Muscle Activation ◽  
Motor Units ◽  
Temperature Dependent ◽  
Activation Patterns ◽  
Warm Up ◽  
Flight Muscles ◽  
Pheromone Blend

At low ambient temperature Helicoverpa zea male moths engage in warm-up behavior prior to taking flight in response to an attractive female pheromone blend. Male H. zea warm up at a faster rate when sensing the attractive pheromone blend compared with unattractive blends or blank controls ( Crespo et al. 2012 ), but the mechanisms involved in this olfactory modulation of the heating rate during preflight warm-up are unknown. Here, we test three possible mechanisms for increasing heat production: 1) increased rate of muscle contraction; 2) reduction in mechanical movement by increased overlap in activation of the antagonistic flight muscles; and 3) increased activation of motor units. To test which mechanisms play a role, we simultaneously recorded electrical activation patterns of the main flight muscles (dorsolongitudinal and dorsoventral muscles), wing movement, and thoracic temperature in moths exposed to both the attractive pheromone blend and a blank control. Results indicate that the main mechanism responsible for the observed increase in thoracic heating rate with pheromone stimulation is the differential activation of motor units during each muscle contraction cycle in both antagonistic flight muscles. This additional activation lengthens the contracted state within each cycle and thus accounts for the greater heat production. Interestingly, the rate of activation (frequency of contraction cycles) of motor units, which is temperature dependent, did not vary between treatments. This result suggests that the activation rate is determined by a temperature-dependent oscillator, which is not affected by the olfactory stimulus, but activation of motor units is modulated during each cycle.

scholarly journals ENDOTHERMY IN THE SOLITARY BEE ANTHOPHORA PLUMIPES: INDEPENDENT MEASURES OF THERMOREGULATORY ABILITY, COSTS OF WARM-UP AND THE ROLE OF BODY SIZE

1993 ◽  
Vol 174 (1) ◽  
pp. 299-320 ◽  
Author(s):  
G. N. Stone
Keyword(s):  
Ambient Temperature ◽  
Heat Loss ◽  
Body Mass ◽  
Thermal Power ◽  
Thermal Conditions ◽  
Energetic Cost ◽  
Solitary Bee ◽  
Warm Up ◽  
Ambient Temperatures ◽  
Thoracic Temperature

1. This study examines variation in thoracic temperatures, rates of pre-flight warm-up and heat loss in the solitary bee Anthophora plumipes (Hymenoptera; Anthophoridae). 2. Thoracic temperatures were measured both during free flight in the field and during tethered flight in the laboratory, over a range of ambient temperatures. These two techniques give independent measures of thermoregulatory ability. In terms of the gradient of thoracic temperature on ambient temperature, thermoregulation by A. plumipes is more effective before flight than during flight. 3. Warm-up rates and body temperatures correlate positively with body mass, while mass-specific rates of heat loss correlate negatively with body mass. Larger bees are significantly more likely to achieve flight temperatures at low ambient temperatures. 4. Simultaneous measurement of thoracic and abdominal temperatures shows that A. plumipes is capable of regulating heat flow between thorax and abdomen. Accelerated thoracic cooling is only demonstrated at high ambient temperatures. 5. Anthophora plumipes is able to fly at low ambient temperatures by tolerating thoracic temperatures as low as 25 sC, reducing the metabolic expense of endothermic activity. 6. Rates of heat generation and loss are used to calculate the thermal power generated by A. plumipes and the total energetic cost of warm-up under different thermal conditions. The power generated increases with thoracic temperature excess and ambient temperature. The total cost of warm-up correlates negatively with ambient temperature.

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