Piracy mating by large males in a monogamous substrate-breeding cichlid in Lake Tanganyika

Telmatochromis temporalis is a biparental substrate breeding cichlid that mates in size-assortative monogamy at the southern end of Lake Tanganyika. In this population, at least a few months before the rainy season, large males (90–110 mm TL) did not pair. However, they maintained large territories that were defended against conspecific large males and that contained several pairing small males (50–80 mm). Large males occasionally visited the nests of the small pairs in their territories, and selectively took over the nests by attacking the owner male. During the takeover, the large males courted the small females in the nests and might have ejaculated sperm. After the large males left the nests, the small owner males conducted paternal care at the nests. These behaviour patterns of large males are similar to piracy mating reported in other polygamous fish species. The piracy mating of large maleT. temporalis seems to be an alternative tactic when large females are not available.     

Coordinate regulation of DNA damage and type I interferon responses imposes an antiviral state that attenuates mouse gammaherpesvirus type 68 replication in primary macrophages

DNA damage response (DDR) is a sophisticated cellular network that detects and repairs DNA breaks. Viruses are known to activate the DDR and usurp certain DDR components to facilitate replication. Intriguingly, viruses also inhibit several DDR proteins, suggesting that this cellular network has both proviral and antiviral features, with the nature of the latter still poorly understood. In this study we show that irradiation of primary murine macrophages was associated with enhanced expression of several antiviral interferon (IFN)-stimulated genes (ISGs). ISG induction in irradiated macrophages was dependent on type I IFN signaling, a functional DNA damage sensor complex, and ataxia-telangiectasia mutated kinase. Furthermore, IFN regulatory factor 1 was also required for the optimal expression of antiviral ISGs in irradiated macrophages. Importantly, DDR-mediated activation of type I IFN signaling contributed to increased resistance to mouse gammaherpesvirus 68 replication, suggesting that the coordinate regulation of DDR and type I IFN signaling may have evolved as a component of the innate immune response to virus infections.     

Pale and dark dichromatism related to microhabitats in a herbivorous tanganyikan cichlid fish,Telmatochromis temporalis

Dichromatism and habitat utilization of a small herbivorous cichlid fish,Telmatochromis temporalis, were studied in a littoral rocky area of Lake Tanganyika. Individuals of both sexes had either pale or dark body coloration that did not change for long periods. Both sexes defended territories from consexuals, and a male had a harem of several females. Pale fish had territories in exposed areas and dark fish in shaded ones. Larger fish were dominant over smaller consexuals and occupied well-illuminated areas. When pale and dark fish were kept in areas with shaded and lighted backgrounds, respectively, they changed body colour within a few weeks. When pale fish were in well-illuminated areas and dark ones in shaded areas, they were cryptic. BecauseTelmatochromis temporalis are very vulnerable prey in coastal areas, dichromatism may function as antipredator camouflage.     

Hydraulic properties of layered soils influence survival of Rhodes grass (<Emphasis Type="Italic">Chloris gayana</Emphasis> Kunth.) during water stress

Survival of vegetation on soil-capped mining wastes is often impaired during dry seasons due to the limited amount of water stored in the shallow soil capping. Growth and survival of Rhodes grass (Chloris gayana) during soil drying on various layered capping sequences constructed of combinations of topsoil, subsoil, seawater-neutralised residue sand and low grade bauxite was determined in a glasshouse. The aim was to describe the survival of Rhodes grass in terms of plant and soil water relationships. The soil water characteristic curve and soil texture analysis was a good predictor of plant survival. The combination of soil with a high water holding capacity and low soil water diffusivity (e.g. subsoil with high clay contents) with soil having a high water holding capacity and high diffusivity (e.g. residue sand) gave best survival during drying down (up to 88 days without water), whereas topsoil and low grade bauxite were unsuitable (plants died within 18–39 days). Clayey soil improved plant survival by triggering a water stress response during peak evaporative water demand once residue sand dried down and its diffusivity fell below a critical range. Thus, for revegetation in seasonally dry climates, soil capping should combine one soil with low diffusivity and one or more soils with high total water holding capacity and high diffusivity.