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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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Differences in thoracic temperature over time between Helicoverpazea males exposed to different chemical stimuli from firstexposure to the stimulus until take-off. Faster heating rate and lowerthoracic temperature at take-off result in more rapid take-off in malesstimulated with sex pheromone. Treatments are as follows: attractive,Z11-16:Ald + Z9-16:Ald; primary component, Z11-16:Ald; and other treatments,grand mean of the last four treatments (i.e. non-attractive, Z11-16:Ald +Z9-16:Ald + Z11-16:OAc; secondary component, Z9-16:Ald; primary component +acetate, Z11-16:Ald + Z11-16:OAc; and blank, hexane). Dashed line representstime elapsed since the start of the experiment until the start ofshivering.
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Figure 3: Differences in thoracic temperature over time between Helicoverpazea males exposed to different chemical stimuli from firstexposure to the stimulus until take-off. Faster heating rate and lowerthoracic temperature at take-off result in more rapid take-off in malesstimulated with sex pheromone. Treatments are as follows: attractive,Z11-16:Ald + Z9-16:Ald; primary component, Z11-16:Ald; and other treatments,grand mean of the last four treatments (i.e. non-attractive, Z11-16:Ald +Z9-16:Ald + Z11-16:OAc; secondary component, Z9-16:Ald; primary component +acetate, Z11-16:Ald + Z11-16:OAc; and blank, hexane). Dashed line representstime elapsed since the start of the experiment until the start ofshivering.

Mentions: To characterize warm-up behavior in response to different sexualpheromone odors, the following variables were measured: (1) time to startshivering (measured from the start of the experiment; Fig. 2A), (2) core Tth withwhich moths took off (see Materials and methods for definition; Fig. 2B), (3) time spent shivering (Fig. 2C) and (4) the rate of heatingcalculated during shivering (Fig. 2D). Forall measured variables, males exposed to the attractive blend showed asignificant difference when compared with those of the last four treatments(i.e. non-attractive, secondary component, primary component + acetate, andblank; Kruskal–Wallis multiple comparison test,P<0.05). In other words, males that detected theattractive blend started shivering earlier, took off at a lower thoracictemperature, spent less time shivering and heated up at a faster rate than thoseexposed to other olfactory stimuli (excluding the primary component treatment;Fig. 3). Moreover, treatments otherthan the attractive blend and major component alone were not significantlydifferent from each other (Kruskal–Wallis multiple comparison test,P>0.05).


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

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

Differences in thoracic temperature over time between Helicoverpazea males exposed to different chemical stimuli from firstexposure to the stimulus until take-off. Faster heating rate and lowerthoracic temperature at take-off result in more rapid take-off in malesstimulated with sex pheromone. Treatments are as follows: attractive,Z11-16:Ald + Z9-16:Ald; primary component, Z11-16:Ald; and other treatments,grand mean of the last four treatments (i.e. non-attractive, Z11-16:Ald +Z9-16:Ald + Z11-16:OAc; secondary component, Z9-16:Ald; primary component +acetate, Z11-16:Ald + Z11-16:OAc; and blank, hexane). Dashed line representstime elapsed since the start of the experiment until the start ofshivering.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Differences in thoracic temperature over time between Helicoverpazea males exposed to different chemical stimuli from firstexposure to the stimulus until take-off. Faster heating rate and lowerthoracic temperature at take-off result in more rapid take-off in malesstimulated with sex pheromone. Treatments are as follows: attractive,Z11-16:Ald + Z9-16:Ald; primary component, Z11-16:Ald; and other treatments,grand mean of the last four treatments (i.e. non-attractive, Z11-16:Ald +Z9-16:Ald + Z11-16:OAc; secondary component, Z9-16:Ald; primary component +acetate, Z11-16:Ald + Z11-16:OAc; and blank, hexane). Dashed line representstime elapsed since the start of the experiment until the start ofshivering.
Mentions: To characterize warm-up behavior in response to different sexualpheromone odors, the following variables were measured: (1) time to startshivering (measured from the start of the experiment; Fig. 2A), (2) core Tth withwhich moths took off (see Materials and methods for definition; Fig. 2B), (3) time spent shivering (Fig. 2C) and (4) the rate of heatingcalculated during shivering (Fig. 2D). Forall measured variables, males exposed to the attractive blend showed asignificant difference when compared with those of the last four treatments(i.e. non-attractive, secondary component, primary component + acetate, andblank; Kruskal–Wallis multiple comparison test,P<0.05). In other words, males that detected theattractive blend started shivering earlier, took off at a lower thoracictemperature, spent less time shivering and heated up at a faster rate than thoseexposed to other olfactory stimuli (excluding the primary component treatment;Fig. 3). Moreover, treatments otherthan the attractive blend and major component alone were not significantlydifferent from each other (Kruskal–Wallis multiple comparison test,P>0.05).

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