| Title: | Female pheromones modulate flight muscle activation patterns during preflight warm-up |
| Author(s): | Crespo JG; Vickers NJ; Goller F; |
| Address: | "Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA. jose.crespo@utah.edu" |
| ISSN/ISBN: | 1522-1598 (Electronic) 0022-3077 (Print) 0022-3077 (Linking) |
| Abstract: | "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" |
| Keywords: | "Animals *Body Temperature Regulation Female *Flight, Animal/drug effects Male Moths Muscles/drug effects/*physiology Sex Attractants/*pharmacology Smell behavior insect muscle physiology olfaction thermobiology;" |
| Notes: | "MedlineCrespo, Jose G Vickers, Neil J Goller, Franz eng R01 DC006876/DC/NIDCD NIH HHS/ DC 06876/DC/NIDCD NIH HHS/ Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S. 2013/05/24 J Neurophysiol. 2013 Aug; 110(4):862-71. doi: 10.1152/jn.00871.2012. Epub 2013 May 22" |
