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Jing Hu Wail M. Hassan Guorong Chen Yanlin Li Wenqiao Fan Wei Wang 《Ecological Entomology》2019,44(6):800-809
1. The Qilian Mountains represent one of the key livestock‐raising grasslands in China. The two main herbivore species raised in this area – yaks and sheep – are of critical economical value. Grasshoppers compete with these animals for available nutrients, creating multifaceted relationships between livestock, grasshoppers and plants. A clear understanding of such relationships is lacking and is urgently needed to guide conservation efforts. 2. This study aims to document the effects of yak and sheep grazing on grasshopper assemblages and to elucidate the underlying mechanisms of such effects. 3. It is shown here that yaks and sheep impact grasshopper assemblages differently. Grasshopper assemblages exhibited lower density, biodiversity, richness, and evenness of distribution in yak‐grazed pastures than in grazing‐free grasslands. Sheep‐grazed pastures exhibited a dramatically divergent picture, with elevated density, biodiversity and richness, and a slightly decreased evenness of distribution. Grasshoppers were generally larger in grazed pastures than in grazing‐free grasslands, especially in yak‐grazed plots. 4. The present study suggests that differences between yak and sheep pastures in plant assemblage structure and plant traits are probably the underlying forces driving the differences in grasshopper assemblage structure and grasshopper traits, respectively. 5. The study shows that the grasshopper habitat indicator species differ between yak and sheep pastures, raising the possibility that such indicators can be used to monitor grassland usage and degradation in the Qilian Mountains. 6. These results provide novel insights into the dynamic interactions of common domesticated herbivore species, grasshoppers and plants in Qilian Mountains, which augment current knowledge and may ultimately lead to better conservation practices. 相似文献
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Chang‐Yong Ma Warren Y. Brockelman Lydia E. O. Light Thad Q. Bartlett Peng‐Fei Fan 《American journal of primatology》2019,81(8)
According to the sexual selection hypothesis, infanticide during resident male replacement is an adaptive strategy that has evolved because the killing of unweaned offspring sired by previous males shortens the inter‐birth intervals of the mothers whose infants are targeted and thereby increases the reproductive fitness of the perpetrator. To test this hypothesis, we describe previously unreported cases of primary male replacement for two gibbon species (Hylobates lar and Nomascus nasutus), and review all other reported cases of primary male replacement in gibbons. Overall, infants were present in nearly half of all cases (16/33, 48%) and of the 18 infants present during replacement, 50% (N = 9) disappeared within 2 months of the event. In four of the five cases where there was sufficient demographic information to identify the likely sire of the subsequent offspring of females that lost infants, the new male was believed to be the sire. Infants were also less likely to die or disappear if the new male and original resident male were possible kin. However, there was no significant difference in the age of infants between those that died or disappeared following replacement and those that survived to weaning (p = .630). Our review of takeover‐related infant loss in gibbons confirms that periods of male instability are risky for unweaned infants and that replacing males benefit from infant loss. Nevertheless, variability in the context of infant loss and difficulties related to data collection in the field make it difficult to test competing hypotheses concerning the mechanisms and functions of infanticide in the small apes. 相似文献
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Ye Yu Xiao-Jing Liu Xiao Ma Zhong-Jie Zhang Tai-Chu Wang Fan Sun Cheng-Xiang Hou Mu-Wang Li 《Insect Science》2020,27(1):2-13
The silkworm Bombyx mori is an important lepidopteran model insect in which many kinds of natural mutants have been identified.However,molecular mechanisms of most of these mutants remain to be explored.Here we report the identification of a gene Bm-app is responsible for the silkworm minute wing(mw)mutation which exhibits exceedingly small wings during pupal and adult stages.Compared with the wild type silkworm,relative messenger RNA expression of Bm-app is significantly decreased in the ul 1 mutant strain which shows mw phenotype.A 10 bp insertion in the putative promoter region of the Bm-app gene in mw mutant strain was identified and the dual luciferase assay revealed that this insertion decreased Bm-app promoter activity.Furthermore,clustered regularly interspaced short palindromic repeats/RNA-guided Cas9 nucleases-mediated depletion of the Bm-app induced similar wing defects which appeared in the mw mutant,demonstrating that Bm-app controls wing development in B.mori.Bm-app encodes a palmitoyltransferase and is responsible for the palmitoylation of selected cytoplasmic proteins,indicating that it is required for cell mitosis and growth during wing development.We also discuss the possibility that Bm-app regulates wing development through the Hippo signaling pathway in B.mori. 相似文献
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B D Chen L Sensenbrenner K Fan Q Y Run 《Journal of immunology (Baltimore, Md. : 1950)》1992,148(3):753-759
Murine peritoneal exudate macrophage (PEM) coexpress receptors for both granulocyte-macrophage CSF (GM-CSF) and macrophage CSF (M-CSF) and can be induced by both factors, either alone or in combination, to undergo extensive proliferation in vitro. In this study the effect of murine rIL-4 (MurIL-4) on the proliferation of PEM was examined. MurIL-4 alone did not support macrophage proliferation but prolonged their survival in vitro. When MurIL-4 was combined with human (Hu)rM-CSF, it enhanced the proliferative response of PEM to rHuM-CSF in a dose-dependent manner, reaching a maximum at approximately 10 ng/ml. Contrarily, MurIL-4 suppressed the proliferative response of PEM to MurGM-CSF. Receptor binding assays using radiolabeled ligands showed that MurIL-4 selectively enhanced the expression of M-CSF receptors; suggesting that at least part of the synergistic effect of MurIL-4 is mediated at the receptor level. Of relevance to this effect is the finding that MurIL-4 greatly promoted the responsiveness of PEM to low concentrations of HurM-CSF. Unlike M-CSF receptors, however, MurIL-4 treatment failed to modulate the levels of GM-CSF receptors in PEM. The proliferative responses of PEM to both MurGM-CSF and HurM-CSF could be inhibited by MurIFN-gamma with similar sensitivity. This inhibitory effect of MurIFN-gamma was partially neutralized by MurIL-4 in cultures containing HurM-CSF but not those containing MurGM-CSF. This study demonstrates that IL-4 is involved directly in the regulation of macrophage production by modulating their responsiveness to various cytokines. 相似文献
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101 species of oribatid mites and 12 species of helminths--anoplocephalids, transmitted by these mites, were found out by Soviet-Vietnam studies in agroecosystems and tropical forests of northern and southern Vietnam. Helminths were recorded from graminivorous mammals as follows: horses, zebu, sheep, goats, buffaloes, deer, hares, elephant, 2 species of rates, 5 species of monkeys and 11 species of birds. 相似文献