Affect regulation (AR) and temperament were examined in children with Autism Spectrum Disorder (ASD). To determine AR, children were exposed to a mildly frustrating situation. Temperament was assessed by the Children's Behavior Questionnaire (CBQ). Children with ASD showed greater variability in AR and used less effective AR strategies compared to controls. Lower academic ability was associated with less effective AR strategies for the ASD while for the controls older age predicted more effective AR strategies. Those with ASD were lower than controls in Attention Focusing, Inhibitory Control, and Soothability. Of the three overarching temperament factors of the CBQ, only Effortful Control but not Negative Affectivity and Surgency/Extraversion distinguished those with ASD from controls. For the ASD group, higher academic ability predicted higher Negative Affectivity. Fewer symptoms and older chronological age predicted higher Effortful Control.

Individuals in social groups of a number of species produce and exchange among themselves frequent, quiet vocalisations. The function of most such vocalisations, here termed 'close' calls, remains obscure, because of the lack of any obvious context of behaviour associated with their production. In this first of two papers that attempt to determine the function of these calls in wild girilla groups, we describe the call repertoire, the age-sex distribution of frequencies of call-types, the contexts in which the calls are given, compare the above measures with available descriptions for the other African great apes, the common and bonobo chimpanzees, and briefly speculate on possible functions. We provide sonograms and 21 acoustical measures of 15 calls in total, including eight 'close' calls, recorded from identified individuals of two habituated heterosexual groups of wild gorillas (Gorilla gorilla) of average composition for the region. In so doing, we provide the most detailed description yet of any great ape's within-group vocalisations. The age-sex classes differed in their use of 'close' calls: adult males called the most in total, immatures the least; and while most classes gave all calls, they gave them at differing frequencies. The differences were consistent across the two-year study period. We suggest two main contexts of production, namely situations of potential separation, and potentially agonistic situations. Thus animals called when far from others and before changes in group activity, and they called when unusually close to one another, especially while feeding. In comparison to the closely related common and bonobo chimpanzees, gorillas apparently had no calls specific to subordinate individuals behaving submissively: subordinate gorillas gave calls in such a situation, but they and dominants gave the same calls (at our current level of analysis) in other situations also. Acoustically and functionally, the gorilla's 'close' calls can be separated into 'syllabled' grunts and non-syllabled' longer calls, we suggest. 'Syllabled' calls might function to maintain contact between animals, to coordinate activity, and to act as mild threats; 'non-syllabled' calls might function as appeasement signals, and to cohere and coordinate group movement when given at good feeding sites, both by attracting animals to the site, and by inhibiting competition at it.

Emerging infectious diseases threaten a wide diversity of animals, and important questions remain concerning disease emergence in socially structured populations. We developed a spatially explicit simulation model to investigate whether-and under what conditions-disease-related mortality can impact rates of pathogen spread in populations of polygynous groups. Specifically, we investigated whether pathogen-mediated dispersal (PMD) can occur when females disperse after the resident male dies from disease, thus carrying infections to new groups. We also examined the effects of incubation period and virulence, host mortality and rates of background dispersal, and we used the model to investigate the spread of the virus responsible for Ebola hemorrhagic fever, which currently is devastating African ape populations. Output was analyzed using regression trees, which enable exploration of hierarchical and non-linear relationships. Analyses revealed that the incidence of disease in single-male (polygynous) groups was significantly greater for those groups containing an average of more than six females, while the total number of infected hosts in the population was most sensitive to the number of females per group. Thus, as expected, PMD occurs in polygynous groups and its effects increase as harem size (the number of females) increases. Simulation output further indicated that population-level effects of Ebola are likely to differ among multi-male-multi-female chimpanzees and polygynous gorillas, with larger overall numbers of chimpanzees infected, but more gorilla groups becoming infected due to increased dispersal when the

Science is fairly certain that the gorilla lineage separated from the remainder of the hominoid clade about eight million years ago,2, 4 and that the chimpanzee lineage and hominin clade did so about a million years after that.1, 2 However, just this year, 2007, it was discovered that although the human head louse separated from the congeneric chimpanzee body louse (Pediculus) around the same time as the chimpanzee and hominin lineages split,3 the human pubic louse apparently split from its sister species, the congeneric gorilla louse, Pthirus, 4.5 million years after their host lineages split.3 No tested explanations exist for the discrepancy. Much is known about hominin evolution, but much remains to be discovered. The same is true of primate socioecology in general and gorilla socioecology in particular.

The present observations of wild gorillas demonstrate that lactation has a major influence on birth spacing. The frequency of suckling declined as infants matured, from greater than 1/h during the first year to about 1/2 h by 30-36 months when mothers usually resumed sexual cycling. In contrast, the length of suckling bouts remained relatively constant throughout lactation, averaging between 2.6 and 3.2 min per bout. Within infant age categories, suckling frequencies of less than or equal to 0.5 bouts/h were associated with mothers who had resumed cycling, whereas higher frequencies were associated with mothers who were still anoestrous. These results complement those obtained from studies of breast-feeding in humans, and support the suggestion that the frequency of suckling is a critical factor in the contraceptive effects of lactation.