Parasites increase fluctuating asymmetry of maleDrosophila nigrospiracula: Implications for sexual selection |
| |
Authors: | Michael Polak |
| |
Institution: | (1) Department of Zoology, Arizona State University, 85287-1501 Tempe, AZ, USA |
| |
Abstract: | Fluctuating asymmetry (minor deviations from perfect bilateral symmetry) is manifested by individuals less able to buffer
environmental stress during development. I utilized a system of two naturally-occurring parasites ofDrosophila nigrospiracula to test whether parasitic infection during host development yields elevated degrees of fluctuating asymmetry in two morphological
traits of males. This hypothesis has important implications for sexual selection, as it may explain why asymmetric males are
often found to be sexually disadvantaged. In my system, nematodes infect larvae and therefore are more likely to disrupt development
than mites which only parasitize adult flies. As predicted, nematode-infected maleD. nigrospiracula had a higher degree of bristle asymmetry than did mite-infested and control (carrying neither parasite) males. There was
also a significant relation between nematode number and degree of asymmetry. There was a significant negative relation between
nematode load and size of adult males, implicating a causal link between nutritional stress during host development and fluctuating
asymmetry. Patterns of wing length asymmetry were inconsistent with those of bristle asymmetry. Nematode-infected males did
not differ in wing length asymmetry relative to mite-infested and control males, nor was there a significant relation between
nematode number and wing asymmetry. This inconsistency in expression of asymmetry may reflect different intensities of selection
operating on each morphological trait. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|