Cooperating elephants mitigate competition until the stakes get too high.

Cooperation is ubiquitous in the animal kingdom as it aims to maximize benefits through joint action. Selection, however, may also favor competitive behaviors that could violate cooperation. How animals mitigate competition is hotly debated, with particular interest in primates and little attention paid thus far to nonprimates. Using a loose-string pulling apparatus, we explored cooperative and competitive behavior, as well as mitigation of the latter, in semi-wild Asian elephants (Elephas maximus). Our results showed that elephants first maintained a very high cooperation rate (average = 80.8% across 45 sessions). Elephants applied "block," "fight back," "leave," "move side," and "submission" as mitigation strategies and adjusted these strategies according to their affiliation and rank difference with competition initiators. They usually applied a "fight back" mitigation strategy as a sanction when competition initiators were low ranking or when they had a close affiliation, but were submissive if the initiators were high ranking or when they were not closely affiliated. However, when the food reward was limited, the costly competitive behaviors ("monopoly" and "fight") increased significantly, leading to a rapid breakdown in cooperation. The instability of elephant cooperation as a result of benefit reduction mirrors that of human society, suggesting that similar fundamental principles may underlie the evolution of cooperation across species.

Interaction mechanism of plant-based nanoarchitectured materials with digestive enzymes of termites as target for pest control: Evidence from molecular docking simulation and in vitro studies.

The integration of nanotechnology for efficient pest management is gaining momentum to overcome the challenges and drawbacks of traditional approaches. However, studies pertaining to termite pest control using biosynthesized nanoparticles are seldom. The present study aims to highlight the following key points: a) green synthesis of AgNPs using Glochidion eriocarpum and their activity against wood-feeding termites, b) testing the hypothesis that AgNPs diminish digestive enzymes in termite gut through in silico analysis. The green synthesis route generated spherical PsAgNPs in the size range of 4-44.5 nm exhibiting higher thermal stability with minimal weight loss at 700 °C. The choice and no-choice bioassays confirmed strong repellent (80.97%) and antifeedant activity of PsAgNPs. Moreover, PsAgNPs exposure caused visible morphological changes in termites. Molecular docking simulation indicated possible attenuation of endoglucanase and bacteria-origin xylanase, digestive enzymes from termite gut, through partial blocking of the catalytic site by AgNPs. Altogether, our preliminary study suggests promising potentials of PsAgNPs for pest management in forestry and agriculture sectors to prevent damages to living trees, wood, crops, etc. As sustainable pest management practices demand low risk to the environment and biodiversity therefore, we recommend that more extensive studies should be performed to elucidate the environmental compatibility of PsAgNPs.

[Difference of soil nematode communities between the humus and soil surface layer in the cold temperate coniferous and broadleaved mixed forest of Yulong Snow Mountain Nature Reserve, Yunnan, China]. / çŽ‰é¾™é›ªå±±è‡ªç„¶ä¿æŠ¤åŒºå¯’æ¸©æ€§é’ˆé˜”æ··äº¤æž—è æ®–è´¨å±‚å’ŒåœŸå£¤è¡¨å±‚çº¿è™«ç¾¤è½ç»“æž„å·®å¼‚.

A high-throughput sequencing approach was used to differentiate the nematode communities in the humus and soil surface layer (0-10 cm) in 20 hm2 plot located in the cold temperate coniferous and broadleaved mixed forest of Yulong Snow Mountain Nature Reserve, Lijiang, Yunnan. A total of 5744582 sequences were obtained, which were further annotated to 44 nematode families. In the humus layer, 37 families were recorded, with Tylenchidae (18.1%) being the most dominant family. For trophic groups, bacterivorous, fungivorous and herbivorous were predominant. The soil surface layer had 41 families, with Mononchidae (45.4%) being the most dominant family. The relative abundance of predatory nematode was highest in the soil surface layer. There was no significant difference in the α diversity indices (Shannon, Simpson and Chao1 index) of nematode communities at the OTU level between two habitats. At the family level, however, α diversity of nematode community in the humus layer was significantly lower than in soil surface layer. ß diversity of the nematode community was significantly different in the two habitats, with lower Cody index but high Sorensen non-similarity index in the humus habitat. Results of non-metric multidimensional scaling (NMDS) analysis showed that the internal structure difference of nematode community in the soil surface layer was higher than that in the humus layer.

Small-scale and multi-species approaches for assessing litter decomposition and soil dynamics in high-diversity forests.

PREMISE OF THE STUDY: The relationship between tree species abundance and diversity and soil chemistry has been studied in several ecosystems and at different spatial scales. However, species-specific assessments have mainly been conducted in temperate ecosystems and in monospecific settings, calling for studies from diverse, mixed forests from different ecosystems. METHODS: In a subtropical forest in southern China, under four dominant tree canopy species (Lithocarpus chintungensis, Castanopsis wattii, Schima noronhae, and Manglietia insignis), we assessed species' effect on inter- and intraspecific percentages of litter mass loss, and the effect of species on soil nutrients and soil microbial biomass. RESULTS: Our results show significant differences in litter decomposition for all four species; however, the percentage of litter mass loss was stable under different species. Microbial biomass and soil nutrients presented strong differences under different tree species. Species-specific differences in soil characteristics were seen for carbon-nitrogen-phosphorus relationships. Surprisingly, the correlations between carbon and phosphorus and between nitrogen and phosphorus showed opposite slopes in soils collected under different tree species. DISCUSSION: Our results provide insights into the importance of tree species identity in providing variety to ecosystem processes occurring on the forest floor. We recommend this methodological approach-combining analysis of litter decomposition, soil nutrient concentrations, and microbial biomass-when dealing with species-rich forests.