Abstract
Most models of sexual selection focus on coevolution of male
sexual trait and female preference for the trait. However, whether
the female preference modifies the male trait depends on the overall
receptivity of females, on the importance of the male trait for
the females, on female sampling behaviour, and on female control
over copulation decision. These aspects are often neglected by theoreticians.
Female receptivity, song requirement and preferences were
studied in two Drosophila virilis group species, D.
montana and D. virilis. The main
object of the study was female acceptance/rejection behaviour.
Female wing spreading posture was a signal for males to attempt
copulation, when the female was ready to mate. I used this signal
as an indicator of female acceptance. D. virilis females
were generally very receptive, but there were differences between
females both in receptivity and in responsiveness of the females
to simulated courtship songs. D. virilis female
did not require song and had a low acceptance threshold with a
heterospecific male. These two traits are explained by a high female
receptivity. D. montana females, on the contrary,
had a high acceptance threshold. These females accepted the courting
male only after hearing his song. They also repelled males, which
attempted copulation without female acceptance signal. In this
species the strength of species discrimination did not correlate
with the overall receptivity of the females. Between species hybrid
females (from a cross vir x mo and
from backcross to mo) resembled D.
montana females in their song requirement, but not in
their receptivity. This suggests that these two traits are inherited
independently.
D. montana and D. littoralis females
have previously been found to prefer males with short and dense
sound pulses in wild. These song characters were repeatable among
overwintered males in a fashion different from other song characters.
This shows that song characters involved in sexual selection are
more sensitive to environmental factors than other song traits.
| Identifer | oai:union.ndltd.org:oulo.fi/oai:oulu.fi:isbn951-42-5154-7 |
| Date | 22 February 1999 |
| Creators | Isoherranen, E. (Eija) |
| Publisher | University of Oulu |
| Source Sets | University of Oulu |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis, info:eu-repo/semantics/publishedVersion |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess, © University of Oulu, 1999 |
| Relation | info:eu-repo/semantics/altIdentifier/pissn/0355-3191, info:eu-repo/semantics/altIdentifier/eissn/1796-220X |
Page generated in 0.0022 seconds