Environmental and Social Factors Associated with the Occurrence of Stone-Handling Behavior in a Captive Troop of <Emphasis Type="Italic">Macaca fuscata</Emphasis>

Stone-handling, a documented behavioral tradition in Japanese macaques (Macaca fuscata), occurs in both captive and provisioned free-ranging troops. We utilize data systematically collected as part of a broader investigation of stone-handling behavior in a captive troop to elucidate the environmental and social factors responsible for its occurrence. We analyzed contexts of stone-handling over 18 mo to determine under what conditions individuals most often perform it. There is clear seasonal variation in the occurrence of stone-handling. The lowest number and shortest duration of stone-handling bouts were in winter, gradually increasing to a peak in summer, and again decreasing toward autumn. Monkeys stone-handled more on clear sunny days than on cloudy or rainy ones. They displayed the behavior less under stressful conditions caused by human intervention or by aggression among troop members. Such stressful social conditions appeared to decrease individual motivation for stone-handling. In other words, individuals most frequently performed stone-handling under more relaxed environmental and social conditions. The findings are consistent with the hypothesis that stone-handling is a form of solitary object play behavior in macaques.     

The first case of dental flossing by a Japanese macaque (<Emphasis Type="Italic">Macaca fuscata</Emphasis>): implications for the determinants of behavioral innovation and the constraints on social transmission

We report the first case of dental flossing behavior by a Japanese macaque. We used cross-sectional data to assess the presence of this novel tool-use behavior at the group-level. Although this behavior was performed frequently by a central middle-ranking middle-aged female during her grooming interactions, and appeared at least four years ago, it remained idiosyncratic to its innovator, and until now has not spread to other group members. We examined the factors that may have favored this innovation, including the environmental context, the individual characteristics of the innovator, and the structural and functional aspects of the behavior. Group size, kinship, and dominance are socio-demographic factors that are likely to limit the opportunities for any group member to observe the innovator, and thus constrain the diffusion of this potential candidate as a new behavioral tradition. This is one of the rare studies to document the spontaneous appearance of tool-use behavior in primates under natural conditions. Identifying the determinants of innovations and the constraints on their diffusion within social groups of non-human primates is of special interest to understanding cultural evolution.     

Fatty acid composition of Goniobasis virginica, Physa sp. and Viviparus malleatus (Mollusca: Gastropoda) from Lake Musconetcong, New Jersey

Gas—liquid chromatographic studies were done to determine the fatty acid composition of Goniobasis virginica Physa sp., and Viviparus malleatus (Mollusca: Gastropoda), from Lake Musconetcong, NJ, U.S.A. Palmitic acid was the predominant saturated fatty acid, followed by stearic acid, in all three molluscan species. The chief monoenes were 16:n−7, 18:1n−7; 20:1n−11+9, and 22:1n−11+13, which together accounted for all monoene fatty acids and one-quarter of the total fatty acids. Considerable amounts of linolenic acid (2.7−4.1%) and arachidonic acid (7.8−12%) were found in all three species. The percentage composition of docosahexaenoic acid (22:6n−3) was low compared to that of eicosapentaenoic acid (22:5n−3). Non-methylene interrupted dienes (20:2 NMID), characteristic of marine molluscs, ranged from 2 to 3% in the three species of freshwater snails.     

A quantitative assay for neomycin phosphotransferase activity in plants

A sensitive, simple, and quantitative assay for determining neomycin phosphotransferase (NPT) activity in plant cell extracts is described. The procedure retains the simplicity of previously published methods, yet offers up to a 140-fold increase in sensitivity. This increase is due to (1) the addition of bovine serum albumin (BSA) to the assay mixture, (2) desalting of crude maize extracts to remove a low-molecular-weight inhibitor of the enzyme, and (3) use of a different extraction buffer and an improved extraction procedure to liberate more enzyme from the cells. This method has been used successfully to detect and quantitate both stable and transient expression of NPT in transgenic tobacco and maize tissue.     

Infectivity, growth, development and pathology of Echinostoma caproni (Trematoda) in the golden hamster

Laboratory hamsters (Mesocricetus auratus) were experimentally infected with 75 ± 15 metacercarial cysts of Echinostoma caproni. Worms were recovered from days 7 to 89 post-infection with eight to 90 (average 37) parasites in the small intestine. Worm wet weights averaged 0.85 mg at 10 days, 1.8 mg at 17 days, 3.4 mg at 45 days, and 7.7 mg at 89 days; average dry weights for the identical days were, 0.15, 0.30, 0.70 and 2.2 mg, respectively. The average body area of worms fixed in hot (80°C) alcohol-formalin-acetic acid was 0.21 mm² on day 3, 4.9 mm² on day 10, and 17.7 mm² on day 42. Clinical signs in some hamsters included progressive unthriftiness and watery diarrhea. Gross examination revealed enlarged lymphatic nodules along the length of the small intestine. The histopathological responses of hamsters to the parasite showed erosion of the intestinal villi with lymphocytic infiltration being the primary response; hemorrhagic areas were also observed in the villi.