Award Date

5-1-2013

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Science

First Committee Member

Allen G. Gibbs

Second Committee Member

Laurel Raftery

Third Committee Member

Haroon Stephen

Fourth Committee Member

John Mercer John Mercer

Fifth Committee Member

David Lee

Number of Pages

71

Abstract

The importance of flying insects cannot be understated; without them as pollinators, the great diversity of flowing plants could not have occurred. Flight requires a suite of highly derived morphological and physiological characteristics that may limit the evolutionary responses of other life history traits.

To investigate the complexities of maneuvering flight, I used high-speed videography to analyze wing and body motions in the HoverflySyritta pipiens(Order: Diptera) during horizontal turns called saccades. I characterized the saccades by calculating the instantaneous rotational velocities throughout the saccade, maximum rotational velocity, and the mean rotational velocity. I then compared the shape of the rotational velocity curve to previous research on the saccades ofDrosophila melanogasterto determine if, likeDrosophila, saccades of S. pipiens are stereotypical behaviors triggered by an avoidance response and are consistent in the magnitude of the rotation and in the time to complete the turn. I also found that, unlikeDrosophilathat accelerate to the maximal rotation velocity more quickly than they decelerate, inS. pipienssaccades acceleration/deceleration times could be equal, or flies could take a longer time to accelerate than decelerate, or a shorter time to accelerate than decelerate. This suggests thatS. pipienssaccades are more variable, and under greater control by S. pipiens than has previously been found inD. melanogaster. InD. melanogaster, body torque is generated by asymmetry in wing stroke amplitude between the inner and outer wings. I measured stroke amplitude duringS. pipienssaccades and found that no asymmetry in wing stoke amplitude could be found that could be associated with the generation of body torque.

Wing loading, the ratio of wing area to mass, has been shown to be a predictor of flight performance in flying animals. Increases in wing loading have been found to increase the energetic cost of flight and result in lower overall flight performance. I studied the effect of increased wing loading in flies that had undone laboratory selection for resistance to desiccation and starvation.

Desiccation selected flies had wing loadings significantly higher than their controls but did not differ in flight velocity (total, horizontal, vertical) or flight angle during take-off. Starvation resistance flies, with higher wing loadings than their controls, had significantly lower vertical flight velocity and flight angle during take-off flights. However, starvation resistance flies did not have significantly different wing loadings than the desiccation resistant flies, suggesting that other mechanisms might be responsible for lower vertical flight velocities and take-off angles.

Keywords

Desiccation; Flight; Insects – Flight; Resistance; Starvation; Takeoff

Disciplines

Biology | Entomology

Language

English


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