Conspicuous differences in floral morphology are partly responsible for reproductive isolation between two sympatric species of monkeyflower because of their effect on visitation of the flowers by different pollinators. Mimulus lewisii flowers are visited primarily by bumblebees, whereas M. cardinalis flowers are visited mostly by hummingbirds. The genetic control of 12 morphological difference...

The objectives of this research were to partition variation in ovulatory follicle size into genetic and nongenetic components and to assess the utility of ovulatory follicle size as an indicator trait associated with reproductive success in beef cattle. Data were collected during the years 2002 to 2005 from 780 beef females that ranged in age from 1 to 12 yr (mean of 2.4 observations per female...

The evolution of inflorescence size, a key trait in reproductive success, was studied in the genus Acer under a perspective of adaptive evolution. Breeding systems, hypothesized to indicate different levels of mating competition, were considered as the selective scenarios defining different optima of inflorescence size. Larger inflorescences, which increase male fitness by generating larger flo...

A critical step in ecological speciation is the development of reproductive isolation. The processes leading up to reproductive isolation are difficult to study since they often occur over very long time periods. Populations of European whitefish (Coregonus lavaretus) has gone through reticulate divergent evolution in many Scandinavian lakes during the last 10 000 years. Some populations even e...

More and more evidence shows that mating preference is a mechanism that can lead to a reproductive isolation event. In this paper, we consider a haploid population living on two patches linked by migration. Individuals are ecologically and demographically neutral on the space and differ only on a trait, a or A, determining both mating success and migration rate. The special feature of this pape...

Most conspicuous organisms are multicellular and most multicellular organisms develop somatic cells to perform specific, nonreproductive tasks. The ubiquity of this division of labor suggests that it is highly advantageous. In this article I present a model to study the evolution of specialized cells. The model allows for unicellular and multicellular organisms that may contain somatic (termina...

Lifetime reproductive performance is a major issue for the Northern Australian beef industry. Delayed cycling of lactating cows after parturition is one of major causes of reproductive inefficiency and impacts on the profitability of beef businesses. In the CRC for Beef Genetic Technologies, genetic markers have been used to develop prediction equations for the improvement of post partum anoest...

usefulness of Japanese quail (Coturnix coturnix japonica) as an expenT z n t a l animal was first pointed out about eight years ago (WILSON, ABBOTT and ABPLANALP 1959, 1961; PADGETT and IVEY 1959). These birds have steadily gained in popularity since then, but few quantitative genetic studies have been reported to date. The present investigation was designed to assess the response of Japanese q...