Soares R.P.P., Dujardin Jean-Pierre, Schofield C.J., Diotaiuti L. (1996). Wing symmetry and flight activity. Memorias do Instituto Oswaldo Cruz, 91 (no spécial), p. 143. ISSN 0074-0276.
Titre du document
Wing symmetry and flight activity
Année de publication
1996
Type de document
Article
Auteurs
Soares R.P.P., Dujardin Jean-Pierre, Schofield C.J., Diotaiuti L.
Source
Memorias do Instituto Oswaldo Cruz, 1996,
91 (no spécial), p. 143 ISSN 0074-0276
We compared bilateral structures (wings) of flying versus non-flying insects in two lines of P. megistus which differed only by their laboratory maintenance time : PM1 (more than five generations in insectarium) and PM2 (one or two generations under laboratory conditions). Insects were processed according to Schofield (1980) and observed through a period of 30 days. During this time the insects that had flight (gf, for "good" flyers) and their wings extracted for morphometry. At the end of this period the same number of insects that did not fly (bf, for "bad" flyers), were used as a control and submitted to the same analysis. Fluctuating asymmetry (FA) was estimated at nine distances (A, B, C, D, E, H, 1, 2 and 3). FA occurs as a result of random deviations in the developement of bilaterally symmetric traits, and is considered as a useful trait for monitoring stress in the laboratory and in natural environments (Parsons, 1990). For each sample, FA values were calculated for each character as the sum of the squared signed differences between sides divided by the number of individuals sampled, i.e., ((Li-Ri)2)/N). This is equivalent to index 5 of Palmer and Strobek (1986) which they state is best able to discriminate true differences in FA. As the index to estimate asymmetry is a variance, differences between samples were tested for significance using tests of homogeneity of variances (Ho : s1=s2). Due to low sample size, statistical analysis was not applied to PM2 females (only two individuals). The PM1 bf females (6 insects) were more asymmetric than their gf counterparts (5 insects) at four wings traits (2,3 in PM1 and 2 in PM2) (gf=7 insects and bf=7 insects). Conversely, one character out of nine was found more asymmetric in gf either from PM1 (character 3 for PM1 females and E for PM1 males) or PM2 males (character D). (Résumé d'auteur)
