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Pheromone mediated modulation of pre-flight warm-up behavior in male moths.

Crespo JG, Goller F, Vickers NJ - J. Exp. Biol. (2012)

Bottom Line: This resulted in less time spent shivering and faster heating rates.Two interesting results emerge from these experiments.Our results shed light on thermoregulatory behaviour of unrestrained moths associated with the scramble competition for access to females and suggest ecological trade-offs between rapid flight initiation and sub-optimal flight performance.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Utah, Salt Lake City, UT 84112, USA. jose.crespo@utah.edu

ABSTRACT
An essential part of sexual reproduction typically involves the identification of an appropriate mating partner. Males of many moth species utilize the scent of sex pheromones to track and locate conspecific females. However, before males engage in flight, warm-up by shivering of the major flight muscles is necessary to reach a thoracic temperature suitable to sustain flight. Here we show that Helicoverpa zea males exposed to an attractive pheromone blend (and in some instances to the primary pheromone component alone) started shivering earlier and took off at a lower thoracic temperature than moths subjected to other incomplete or unattractive blends. This resulted in less time spent shivering and faster heating rates. Two interesting results emerge from these experiments. First, the rate of heat generation can be modulated by different olfactory cues. Second, males detecting the pheromone blend take off at lower thoracic temperatures than males exposed to other stimuli. The take-off temperature of these males was below that for optimal power production in the flight muscles, thus generating a trade-off between rapid departure and suboptimal flight performance. Our results shed light on thermoregulatory behaviour of unrestrained moths associated with the scramble competition for access to females and suggest ecological trade-offs between rapid flight initiation and sub-optimal flight performance.

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Related in: MedlinePlus

Upper limit traces of maximal vertical force production as a function of corethoracic temperature for each of the 11 Helicoverpa zeamales tested. (A) Vertical force versus core thoracictemperature. (B) Flight muscle mass-specific vertical forceversus core thoracic temperature. The horizontal dashedline depicts the mean vertical force needed to counteract the mean body massof males tested. The vertical dashed line shows the mean core thoracictemperature at which mean maximal vertical force is exerted. The gray areaindicates the range of temperatures at which peak maximal force productionwas observed for different males. Incomplete traces show missing data due todetachment from the force transducer during the experiment.
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Figure 4: Upper limit traces of maximal vertical force production as a function of corethoracic temperature for each of the 11 Helicoverpa zeamales tested. (A) Vertical force versus core thoracictemperature. (B) Flight muscle mass-specific vertical forceversus core thoracic temperature. The horizontal dashedline depicts the mean vertical force needed to counteract the mean body massof males tested. The vertical dashed line shows the mean core thoracictemperature at which mean maximal vertical force is exerted. The gray areaindicates the range of temperatures at which peak maximal force productionwas observed for different males. Incomplete traces show missing data due todetachment from the force transducer during the experiment.

Mentions: To understand whether the lower Tth found inmales that were exposed to the attractive blend (Fig. 2B) manifested itself as a change in flight performance; wemeasured how maximal vertical force varied with Tth.Distributions of maximal vertical force production as a function of coreTth showed that the mean (±s.d.) optimalTth (i.e. the temperature at which the peakforce occurred) was 32.1±1.4°C (N=11; Fig. 4). Using the mass of tested individuals(145.0±26.3 mg), the projected Tth forsufficient force production to stay airborne was approximately 26°C. Onaverage, males produced a maximal vertical force of 1.42±0.26 mN, butmuscle response to temperature varied substantially (Fig. 4A). A similar distribution was observed when maximalvertical force was calculated based on thoracic muscle mass (Fig. 4B). Finally, the mean maximal verticalforce found in this study was 67.0±16.2 N kg–1 flightmuscle, which lies within the values found by Marden (Marden, 1987) for a wide variety of insects and otheranimals.


Pheromone mediated modulation of pre-flight warm-up behavior in male moths.

Crespo JG, Goller F, Vickers NJ - J. Exp. Biol. (2012)

Upper limit traces of maximal vertical force production as a function of corethoracic temperature for each of the 11 Helicoverpa zeamales tested. (A) Vertical force versus core thoracictemperature. (B) Flight muscle mass-specific vertical forceversus core thoracic temperature. The horizontal dashedline depicts the mean vertical force needed to counteract the mean body massof males tested. The vertical dashed line shows the mean core thoracictemperature at which mean maximal vertical force is exerted. The gray areaindicates the range of temperatures at which peak maximal force productionwas observed for different males. Incomplete traces show missing data due todetachment from the force transducer during the experiment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368620&req=5

Figure 4: Upper limit traces of maximal vertical force production as a function of corethoracic temperature for each of the 11 Helicoverpa zeamales tested. (A) Vertical force versus core thoracictemperature. (B) Flight muscle mass-specific vertical forceversus core thoracic temperature. The horizontal dashedline depicts the mean vertical force needed to counteract the mean body massof males tested. The vertical dashed line shows the mean core thoracictemperature at which mean maximal vertical force is exerted. The gray areaindicates the range of temperatures at which peak maximal force productionwas observed for different males. Incomplete traces show missing data due todetachment from the force transducer during the experiment.
Mentions: To understand whether the lower Tth found inmales that were exposed to the attractive blend (Fig. 2B) manifested itself as a change in flight performance; wemeasured how maximal vertical force varied with Tth.Distributions of maximal vertical force production as a function of coreTth showed that the mean (±s.d.) optimalTth (i.e. the temperature at which the peakforce occurred) was 32.1±1.4°C (N=11; Fig. 4). Using the mass of tested individuals(145.0±26.3 mg), the projected Tth forsufficient force production to stay airborne was approximately 26°C. Onaverage, males produced a maximal vertical force of 1.42±0.26 mN, butmuscle response to temperature varied substantially (Fig. 4A). A similar distribution was observed when maximalvertical force was calculated based on thoracic muscle mass (Fig. 4B). Finally, the mean maximal verticalforce found in this study was 67.0±16.2 N kg–1 flightmuscle, which lies within the values found by Marden (Marden, 1987) for a wide variety of insects and otheranimals.

Bottom Line: This resulted in less time spent shivering and faster heating rates.Two interesting results emerge from these experiments.Our results shed light on thermoregulatory behaviour of unrestrained moths associated with the scramble competition for access to females and suggest ecological trade-offs between rapid flight initiation and sub-optimal flight performance.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, University of Utah, Salt Lake City, UT 84112, USA. jose.crespo@utah.edu

ABSTRACT
An essential part of sexual reproduction typically involves the identification of an appropriate mating partner. Males of many moth species utilize the scent of sex pheromones to track and locate conspecific females. However, before males engage in flight, warm-up by shivering of the major flight muscles is necessary to reach a thoracic temperature suitable to sustain flight. Here we show that Helicoverpa zea males exposed to an attractive pheromone blend (and in some instances to the primary pheromone component alone) started shivering earlier and took off at a lower thoracic temperature than moths subjected to other incomplete or unattractive blends. This resulted in less time spent shivering and faster heating rates. Two interesting results emerge from these experiments. First, the rate of heat generation can be modulated by different olfactory cues. Second, males detecting the pheromone blend take off at lower thoracic temperatures than males exposed to other stimuli. The take-off temperature of these males was below that for optimal power production in the flight muscles, thus generating a trade-off between rapid departure and suboptimal flight performance. Our results shed light on thermoregulatory behaviour of unrestrained moths associated with the scramble competition for access to females and suggest ecological trade-offs between rapid flight initiation and sub-optimal flight performance.

Show MeSH
Related in: MedlinePlus