We examined interspecific female mating preferences in four closely related species of cichlid belonging to the Pseudotropheus zebra species complex of Lake Malawi. These species differ in coloration but are similar in other respects, suggesting that male color patterns may be important to female mate choice in species recognition. To test this hypothesis, we presented females from each species with a choice of four males, one of her own species and three others that were each of a different species. We also gave each female a choice between the three heterospecific males only. In all four species, females showed a significant preference for conspecific males in the four-way choice and chose the male with the most similar color pattern to the conspecific male in the three-way choice. These results are discussed with reference to the theory of sexual selection on color patterns as a means of sympatric speciation in cichlids.

SUMMARY: It has been hypothesized that the physical properties of the environment exert selection pressure on long-range acoustic communication signals to match the local habitat by promoting signal characteristics that minimize excess attenuation and distortion. We tested this in a unique family of bladder grasshoppers notable for producing a signal with a 2 km maximum transmission distance. In direct performance comparisons, male advertisement calls of seven species were broadcast through four vegetation biomes – forest, fynbos,savanna and succulent karoo. The calls of species native to forest and fynbos biomes propagated with lower levels of distortion over distance in their respective habitats relative to those of non-native species, while fynbos species also performed best in the remaining two habitats. In addition, both forest and fynbos species had low levels of signal attenuation over distance in all environments. The fynbos biome was characterized by high inconsistency in signal degradation, while the forest biome had the highest levels of environmental noise. Innate habitat characteristics, leading to comparatively limited acoustic communication distances in the forest and fynbos relative to the savanna and succulent karoo, may therefore explain the need for a higher quality of signal transmission in grasshoppers inhabiting the former two environments.

Although the processes that promote biodiversity remain poorly understood, geographic variation resulting from selection and/or neutral processes is thought to be a precursor to allopatric speciation. An examination of intraspecific divergence in multiple traits and their co-variation is an essential part of understanding the origin of new species. Here we investigate patterns of geographic variation in acoustic, morphological and genetic characters of allopatric populations of the bladder grasshopper Bullacris unicolor. We found significant geographic variation in both temporal and frequency components of male advertisement calls, as well as in morphological variables of males and females. However, acoustic characters were much more strongly differentiated between populations than were morphological characters, with no correlation between acoustic and morphological traits. Furthermore, analysis of the mitochondrial DNA marker cytochrome c oxidase I indicated strong genetic structuring, pointing towards genetic isolation among populations in the absence of isolation by distance. Furthermore, we found genetic distance was significantly correlated with morphological differentiation, but not with acoustic differentiation. The high levels of variation in male advertisement calls between populations, as well as the lack of association between acoustic and genetic distance, suggests that divergence in acoustic traits cannot be attributed to genetic features, and is more likely due to alternative selective pressures, such as mate choice or the ecological environment. Our results further suggest that morphological and acoustic features are uncorrelated at the intraspecific level and appear to be evolving under separate selective pressures.

Natural landscapes are increasingly fragmented due to human activity. This contributes to isolation and inadequate gene flow among wildlife populations. These threats intensify where populations are already low, and gene flow is compromised. Ensuring habitat connectivity despite transformed landscapes can mitigate these risks. Leopards are associated with high levels of biodiversity and are the last widely occurring, free-roaming apex predator in South Africa. Although highly adaptable, leopard survival is reduced by human-caused mortality and habitat destruction. We aimed to assess the connectivity of leopard habitat in the Eastern Cape and Western Cape, South Africa. We predicted leopard habitat by correlating GPS data from 31 leopards to environmental features that included human-associated and natural landscapes. We used circuit theory to delineate corridors linking known leopard populations. Finally, using camera traps, we tested whether five predicted corridors were used by leopards. Leopard habitat was strongly correlated to moderate slopes and areas of natural land-cover and plantations, highlighting mountainous areas as important habitat with high connectivity probability. While most habitat patches showed some level of connectivity, leopards avoided highly transformed landscapes, potentially isolating some populations. Where corridors are not functional, active conservation measures for species connectivity becomes important.

"Female preferences for male calling songs in the bladder grasshopper Bullacris membracioides" published on 01 Jan 2006 by Brill.