1. Predator-prey interactions, especially those involving herbivorous insects, are of great importance in maintaining biodiversity. Predation pressure varies temporally in response to prey availability and activity. However, little is known about the patterns and drivers of fluctuations in predation pressure at fine temporal scales.2. Artificial caterpillars (placed on plant leaves at breast height) were used to assess changes in predation pressure across four time intervals of the day in a monsoonal tropical rainforest in south-west China. The study examined how assemblage composition of arboreal ants, the dominant predators, changed across the same time intervals. The potential linkages between biotic (arboreal ants) and abiotic (temperature and light intensity) factors with predation rate were evaluated.3. Predation rate on caterpillars during the early part of the night (19.00-01.00 hours) was significantly higher than in the morning, afternoon, or late night. Ant assemblage composition, rather than species richness or total abundance, best explained the variations in predation rate on artificial caterpillars. 4. The results help to strengthen understanding of trophic interactions by demonstrating that predation pressure fluctuates at finer timescales than previously tested, and that a particular set of ant species may play major roles in predation on caterpillars and possibly other organisms.

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Sheep sometimes develop an abnormal behavior termed as wool-biting when kept in an indoor system; however, little is known about this behavior. As the provided feed type may affect the foraging behavior and repress abnormal behavior in animals, we tested the effect of feed type on repressing wool-biting behavior in this study. We used hay prepared in three forms, that is hay bales, rolls and cubes. The wool-biting frequency associated with hay bales was significantly higher than that associated with rolls (P < 0.05) and cubes (P < 0.05); however, there was no significant difference between rolls and cubes. For hay rolls, wool-biting significantly decreased after feeding (P < 0.05), suggesting that rolls may provide sheep with appropriate oral stimulation; thus, decreasing the post-feeding oral abnormal behavior. An individual difference of wool-biting behavior between sheep was also detected, and an unexpected bed-eating behavior was found in the hay cube treatment. We suggest that sheep performing movements that are similar to their natural foraging behavior while grazing would repress wool-biting behavior, which happened in hay roll and hay cube treatments. Considering sanitation and animal welfare, providing sheep with hay rolls may provide an easier method to control wool-biting behavior in housed sheep.

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Pipe model theory has the potential to be widely applied in the estimation of tree allometry parameters, although it remains uncertain whether it can provide accurate estimation of the crown biomass of plantation forest. In this study, an improved pipe model was used for the first time to estimate the crown biomass of Larix olgensis plantations in northeast China. The results of linear regression analysis showed that crown biomass could be accurately estimated from the stem area at the crown base, which could be calculated using the tree height, crown base height, and stem area at breast height. Furthermore, covariance analysis was applied to analyze the differences in site-related factors that affect crown biomass. There was no significant difference between sites in the crown biomass of L. olgensis plantations in the research area, while the effect of tree age on crown biomass estimation should be considered. Our study showed that a modified pipe model could accurately estimate the crown biomass of larch plantations in northeast China, which has great significance for the determination of crown biomass in Chinese plantations using pipe model theory.

Wool-biting behavior in housed sheep is a serious animal welfare problem and is difficult to control. Since we have found that sheep fed on rolled hay performed less post-feeding wool-biting than those fed on baled hay, here we mixed these two kinds of hay in four different proportions (0%, 33%, 67% and 100% of rolled hay) to test the effect of rolled hay on repressing wool-biting behavior. We also measured the pulling force needed to remove a piece of rolled hay, baled hay, wool and fresh grass. Wool-biting occurred most frequently in the treatment containing 0% rolled hay; however, there was no significant difference between the other three treatments. The pulling force needed to remove a piece of baled hay was significantly weaker than that for the other three objects; no other significant differences in pulling force were found. Our results suggest that the wool-biting behavior of sheep was due to feeding frustration, which arises when they lack the appropriate oral stimulation from performing their normal foraging movement; this then redirects to the wool on their pen-mates. Feeding sheep rolled hay, even in low quantities, can provide them with appropriate oral stimulation and was effective in repressing wool-biting behavior.