Influence of Male Mating Behavior on Wing Morphology in Brassolini Butterflies

• Main Author: Frichter, Susan E.
• Format: Others
• Published: ScholarWorks@UNO 2012
• Online Access: http://scholarworks.uno.edu/honors_theses/11; http://scholarworks.uno.edu/cgi/viewcontent.cgi?article=1010&context=honors_theses

The influence of male mating behavior on wing morphology in two genera of the tribe Brassolini, Caligo and Opsiphanes, was examined. This study consisted of fieldwork and laboratory components. During fieldwork, male and female butterflies from each genus were flown through a flight tunnel and recorded with a video camera for further analysis of flight speed in the laboratory. In addition, male and female butterflies were observed in their natural environment, and the differences in their mating and flight behavior were noted. In the laboratory, photographs of previously captured Brassolini butterflies were taken and edited. Each image was adjusted to life size, the wings were overlapped in a standardized way for all specimens, and the forewing length and total wing area for each butterfly were determined subsequently. The image of each butterfly was cut into fifteen arches, weighed, and documented in order to calculate the aspect ratio and wing centroid. After pooling the data for Caligo and Opsiphanes species, the calculated aspect ratio and wing centroid data were used to perform a test in accordance with the determined variance for each of the comparisons. A total of eight comparisons were made as follows: male Caligo aspect ratio versus female Caligo aspect ratio, male Caligo wing centroid versus female Caligo wing centroid, male Opsiphanes aspect ratio versus female Opsiphanes aspect ratio, male Opsiphanes wing centroid versus female Opsiphanes wing centroid, male Caligo aspect ratio versus male Opsiphanes aspect ratio, male Caligo wing centroid versus male Opsiphanes centroid, female Caligo aspect ratio versus female Opsiphanes aspect ratio, and female Caligo wing centroid versus female Opsiphanes centroid. As expected, the results of the statistical analyses showed that although the wing morphology in male and female Caligo did not differ, the wing morphology in male and female Opsiphanes was significantly different due to the difference in activities. In addition, wing morphology of male Caligo and Opsiphanes also differed significantly from one another, while only the aspect ratio in female Caligo and Opsiphanes were significantly different from one another. Thus, these statistical analyses suggested that due to the differences in mating behavior between males of both genera, selection has caused the wing morphology of males in each genus to differ from the other in order to maximize their fitness.