The primary focus of this article is on the so-called negritos of Peninsular Malaysia and southern Thailand, but attention is also paid to other parts of Southeast Asia. I present a survey of current views on the "negrito" phenotype--is it single or many? If the phenotype is many (as now seems likely), it must have resulted from parallel evolution in the several different regions where it has been claimed to exist. This would suggest (contrary to certain views that have been expressed on the basis of very partial genetic data) that the phenotype originated recently and by biologically well-authenticated processes from within the neighboring populations. Whole-genome and physical-anthropological research currently support this view. Regardless of whether the negrito phenotype is ancient or recent-and to the extent that it retains any valid biological reality (which is worth questioning)-explanations are still needed for its continued distinctiveness. In the Malay Peninsula, a distinctive "Semang" societal pattern followed by most, but not all, so-called negritos may have been responsible for this by shaping familial, breeding, and demographic patterns to suit the two main modes of environmental appropriation that they have followed, probably for some millennia: nomadic foraging in the forest, and facultative dependence on exchange or labor relations with neighboring populations. The known distribution of "negritos" in the Malay Peninsula is limited to areas within relatively easy reach of archaeologically authenticated premodern transpeninsular trading and portage routes, as well as of other non-negrito, Aslian-speaking populations engaged in swidden farming. This suggests that their continued distinctiveness has resulted from a wish to maintain a complementary advantage vis-à-vis other, less specialized populations. Nevertheless, a significant degree of discordance exists between the associated linguistic, societal-tradition, and biological patterns which suggests that other factors have also been at play.
Immune restoration disease (IRD) associated with Mycobacterium tuberculosis parallels the reconstitution of a pathogen-specific Th1 response. However, it is not clear whether humoral responses to M. tuberculosis antigens also rise, or whether antibody levels predict IRD. Here, humoral immunity to M. tuberculosis antigens was investigated in four Asian cohorts.
Urbanization is creating a new global biome, in which cities and suburbs around the world often resemble each other more than the local natural areas they replaced. But while urbanization can profoundly affect ecology at local scales, we know little about whether it disrupts large-scale ecological patterns. Here we test whether urbanization disrupts a macroecological pattern central to ecological and evolutionary theory: the increase in seed predation intensity from high to low latitudes. Across 14,000 km of latitude spanning the Americas, we compared predation intensity on two species of standardized experimental seeds in urbanized and natural areas. In natural areas, predation on both seed species increased fivefold from high latitudes to the tropics, one of the strongest latitudinal gradients in species interactions documented so far. Surprisingly, latitudinal gradients in predation were equally strong in urbanized areas despite significant habitat modification. Nevertheless, urbanization did affect seed predation. Compared with natural areas, urbanization reduced overall predation and vertebrate predation, did not affect predation by invertebrates in general, and increased predation by ants. Our results show that macroecological patterns in predation intensity can persist in urbanized environments, even as urbanization alters the relative importance of predators and potentially the evolutionary trajectory of urban populations.