Background: Positive intersexual genetic correlations are typically viewed as constraining the evolution of sexual dimorphism, when traits are subject to sexually antagonistic selection. Our study species, the damselfly Ischnura elegans, has a female-limited colour polymorphism with three female colour morphs (males are monomorphic), one of which is considered to be a male mimic. Questions: Are...

The male of some snake species forms a copulatory plug which occludes the oviductal parts of the female's cloaca for a few days. The plug, apparently formed from secretions of the kidney immediately after insemination, probably prevents rival males from copulating with the same female.

In this paper, several experiments on F0 transformation within the voice conversion framework are presented. The conversion system is based on a probabilistic transformation of line spectral frequencies and residual prediction. Three probabilistic methods of instantaneous F0 transformation are described and compared. Moreover, a new modification of inter-speaker residual prediction is proposed ...

We studied the reproductive behaviour associated with mate choice by size in three species of White Sea molluscs genus Littorina—L. saxatilis, L. obtusata and fabalis. Three behavioural patterns were revealed after a comparative analysis male snails. The males obtusata, regardless their size, could all females but preferred to larger ones. fabalis chose own or larger. saxatilis mated approximat...

Voice conversion is a process which modifies speech produced by one speaker so that it sounds as if it is uttered by another speaker. In this paper a new voice conversion system is presented. The system requires parallel training data. By using linear prediction analysis, speech is described with line spectral frequencies and the corresponding residua. LSFs are converted together with instantan...

Line spectrum pairs (LSPs) are the roots (located in the complex-frequency or -plane) of symmetric and antisymmetric polynomials synthesized using a linear prediction (LPC) polynomial. The angles of these roots, known as line-spectral frequencies (LSFs), implicitly represent the LPC polynomial and hence the spectral envelope of the underlying signal. By exploiting the duality between the time a...

For more than 100 years it has been known that the sclerotised median lobe of beetles harbours a membranous structure (the "internal sac" or "endophallus") which is everted during copula inside the female genital tract. In order to explore the functional role of this structure and those associated with it, we cryofixed copulating pairs of Donacia semicuprea and Lilioceris lilii and studied the ...

Whether nonhuman primates avoid copulating with close kin living in their social group is controversial. If sexual aversion to relatives occurs, it should be stronger in females than in males because of females' greater investment in each offspring and hence greater costs resulting from less viable offspring. Data presented here show that adult male rhesus macaques breeding in their natal group...

Japanese populations of the leaf beetle, Chrysolina aurichalcea, have 2 main karyotypes, Type 31 and Type 41, which greatly differ in chromosome number and form. We examined their geographical distribution and reproductive isolation in southern Hokkaido, northern Japan. Type 41 was widely distributed in the survey area, whereas Type 31 was restricted to a narrow portion. A transect across each ...