Mating success and wing morphometry in Drosophila melanogaster after long-term rearing on different diets

Different environmental factors are important for development, physiology, behaviour and, therefore, adaptation of Drosophila species. Additionally, the presence of genetic and phenotypic variation in traits affecting mate choice forms the basis for sexual selection that may lead to isolation between populations in different nutritive environments. The aim of this research was to determine mating success and wing morphometry of Drosophila melanogaster flies after more than a decade of growing on banana and carrot substrates. Males and females reared on carrot medium were more successful in mating than flies reared on banana diet. Females originating from banana medium rather chose males originating from carrot substrate, while females developed on carrot medium equally chose males developed on both substrates. Differences in wing size and shape were observed between sexes and nutritional strains. Furthermore, the results showed absence of ethological isolation between two ‘nutritional’ strains.

Is there ethological isolation among Drosophila melanogaster strains reared for more than 35 generations on different food?

Ethological isolation among three strains of D. melanogaster reared for more than 35 generations on different food (standard cornmeal-agar-yeast medium, banana, and tomato) was tested in a series of multiple choice tests. Long-term maintenance on different substrates did not contribute to sexual isolation among three 'nutritional strains', as degrees of ethological isolation (Malogolowkin-Cohen's isolation indices) were not statistically significant. Males and females reared on different nutritional resources were equally successful in matings, i.e., significant differences in the number of copulations achieved by males and females from various lines were not observed.

Courtship and mating behaviours of two syntopic species of skink (Plestiodon anthracinus and Plestiodon fasciatus)

Courtship and mating behaviours are widely conserved throughout the scincid lizard genus Plestiodon, and ethological isolation between closely related species depends heavily on differentiating chemical cues. The purpose of this study was to determine whether or not subtle, as yet undetected differences are present in the mating behaviours of two syntopic, distantly related skinks, P. anthracinus and P. fasciatus. Observed courtship and mating behaviours were similar between the two species and to those reported for other species within this genus. However, survival analysis determined significant interspecific differences in the duration of pre-coital behaviours. Investigation of such subtle differences between species more closely related than these two may generate further insights into the evolution of ethological isolating mechanisms in lizards.

Reproductive isolation among three populations of the genus Grammostola from Uruguay (Araneae, Theraphosidae)

Ethological isolation of individuals from three allopatric Grammostola populations of Uruguay, G. iheringi (Keyserling, 1891), G. mollicoma (Auserer, 1875) northern population and G. mollicoma southern population, was tested under laboratory conditions. Grammostola iheringi behaved as a reproductive isolated species, whereas the two populations of G. mollicoma did not show ethological isolation between them. However, ecological isolating reproductive mechanisms could be acting on G. mollicoma populations. Artificial burrows seem to be important for reproductive isolation in these species.

"Prairie Grouse", Tympanuchus cupido × phasianellus, Hybridization on Manitoulin Island, Ontario

Greater Prairie Chickens started their range expansion from Wisconsin about 1900. They reached Sault Ste. Marie, Ontario, by 1925 and completed colonization of Manitoulin Island by 1945. In the fall of 1932, an irruption of Northern Sharp-tailed Grouse from the Hudson Bay Lowlands occurred. Residents of Manitoulin distinguished the two species and reported the presence of “square-tails” and “sharp-tails” in the winter of 1932-1933. There is no specimen evidence or verbal reports that Northern Sharp-tailed Grouse reached Michigan during that irruption. Prairie Sharp-tailed Grouse were in the northern peninsula of Michigan by 1930. In 1941, Michigan Department of Natural Resources made a planting of 37 Prairie Sharptailed Grouse on Drummond Island. Thence they spread east and the first lek was found at the west end of Manitoulin Island in 1952. By 1960, these birds had virtually colonized the whole island. Development of a hybrid index from the morphology of specimens of skins and skeletons from Manitoulin indicated that more than 50% of all birds in the 1960s were hybrids. In Michigan, less than 1% of the birds necropsied or checked in hunters’ bags were hybrid. It seems likely that ethological isolation broke down on Manitoulin Island. The booming display of the Prairie Chicken and the tail rattling display of the Sharp-tailed Grouse can be broken down into their component parts. They appear to be homologous to five discrete displays of the Spruce Grouse, grouped in different patterns in each of the two lek species. There was little hybridization between Prairie Sharptailed Grouse and Prairie Chickens that had lived sympatrically for thousands of years. Northern Sharp-tailed Grouse had probably never lived sympatrically with Prairie Chickens and the evolution of the perception of species distinctions may not have evolved to the point where hybridization was restricted to a rare event.