27Changes in Body Melanisation
and Not Body Size Affect Mating
Success in Drosophila immigrans
Shama Singh
A. K. Chakravarthy (ed.), New Horizons in Insect Science: Towards Sustainable Pest Management,
DOI 10.1007/978-81-322-2089-3_3, © Springer India 2015
S. Singh ()
Department of Zoology, University of Delhi, Delhi
1 10007, India
Department of Genetics, M. D. University, Rohtak,
Haryana 124001, India
e-mail: [email protected]
AbstractWild flies and laboratory strains of Drosophila immigrans were inves-
tigated to study effects due to changes in body size and body melanisa-
tion on mating success (mated pairs, mating latency (ML), and copulation
duration(CD)). Accordingly, the hypothesis, whether changes in body size
or body melanisation are correlated with mating success in D. immigrans,
was tested. A comparison of copulating and noncopulating flies of D. im-
migrans in the field showed contrasting differences due to body melanisa-
tion but not with body size. Similar results were found in copulating flies
with early- vs. late-mating propensity. Isofemale lines varying either in
body melanisation or in body size, but not in both the traits were selected.
Laboratory data on dark vs. light isofemale lines showed a significant ef-
fect of body melanisation on mating success. By contrast, small vs. large
body size strains did not differ in their mating success. Further, laboratory-
selected dark strain showed a significantly higher number of mated pairs
and longer CD as compared with light strain; whereas ML was longer
for light strain and much shorter for dark strain. Thus, changes in mating
success are associated with body melanisation and not with body size in
D. immigrans.Introduction
Mating success is an important component of fit-
ness affected by genetic as well as environmental
factors (Long et al. 1980 ; Markow 1996 ). In some
Drosophila species, females have been shown to
choose their mating partner based on body size.Keywords
Body melanisation · Body size · Copulation duration · Drosophila
immigrans