Seed dispersal by hornets: An unusual insect‐plant mutualism

Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four populations of Stemona tuberosa from 2011–2016, we demonstrate that hornets are the primary seed dispersers of S. tuberosa and play an important role in "long-distance" seed dispersal in this species. Furthermore, some ant species act as secondary dispersers and may transport the seeds to safe sites.Hornets and ants provide complementary seed dispersal at different spatial scales. This unique example of insect-plant mutualism may be an underestimated but important strategy to ensure "long-distance" seed dispersal in other myrmecochorous plants.     

Diversity and evolution of samara in angiosperm北大核心CSCD

Samara (winged fruit) can be dispersed easily by wind and may be a crucial factor for angiosperm spread and diversification. In a narrow sense, a samara is an indehiscent dry fruit with wing(s) developed from fruit pericarp, while in a broad sense samaras also include all winged fruits with wings developed from both pericarp and peri-anth or bracts. According to the wing shape and growth patterns of samaras, we divided samaras into six types, i.e. single-winged, lanceolate-winged, rib-winged, sepal-winged, bract-winged, and perigynous samaras. Perigynous samaras can be further classified into two forms, i.e. round-winged and butterfly-winged samaras. Accordingly, the aerodynamic behavior of samaras can be classified into five types, autogyro, rolling autogyro, undulator, helicopter, and tumbler. The rib-winged and round-winged samaras can be found in Laurales, a basal angiosperm, and may represent the primitive type of early samaras. In the derived clades, samaras evolved enlarged but unequal wings and decreased wing loading (the ratio of fruit weight to wing size), which is likely an adaptation to gentle wind and secondary dispersal through water or ground wind. The wings of some samaras (such as sepal-winged and bract-winged samaras) may have multiple functions including wind dispersal, physical defense for the seeds, and adjust seed germination strategy. The pantropical family Malpighiaceae is extraordinarily rich in samara types, which is likely related to its multiple inter-continent dispersal in history, which is known as “Malpighiaceae Route”. Therefore, Malpighiaceae can be used as a model system for the studies on samara adaptation and evolution. We identified the following issues that deserve further examination in future studies using both ecological and evo-devo methods: 1) the adaption of different types of samaras in dispersal processes, 2) the molecular and developmental mechanism of sepal- and bract-wings, and 3) the evolution of samara types and their effects on angiosperm diversification. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All rights reserved.     

A Dispersal and Vicariance Analysis of the Genus Caragana Fabr.

The genus Caragana Fabr., consisting of approximately 70 species, has a temperate Asian distribution and occurs mainly in the drought and cold regions of the northwestern and southwestern Tibetan Plateau of China. The distribution pattern of the genus was investigated using dispersal-vicariance analysis （DIVA）, The results indicate that vicariance versus dispersal plays a major role in the evolution of the genus and that short-distance dispersal also exists. There is no fossil record of this genus. Therefore, Caragana is inferred as an advanced taxon in terms of its limited temperate Asian distribution. Based on the morphological variation and ecological adaptation in Caragana, the generic speciation is postulated to be related to the uplifting of the Tibetan Plateau and to the increasing arid conditions of Central Asian lands since the Neogene. The Mongolian Plateau and the Tibetan Plateau are hypothesized as the barriers of vicariance between East Asia and western Central Asia.     

苏门白酒草的繁殖特征与入侵性的关系以及某些进化含义

Conyza sumatrensis （Retz.） E. Walker, a member of Asteraceae, is a highly invasive species. However, its reproduction biology remains poorly known. To understand the role of reproductive traits in successful invasion of the species, we studied several traits of its reproductive system： the miniature capitulum and gynomonoecious sexual system, the biology and phenology of capitula and florets, pollen/ovule ratio, the mating system （selfcompatibility）, flower visitors, physical traits and dispersal potential of achenes, germination potential of achenes from manually pollinated capitula, and the association of these traits with invasiveness. Our study showed that the reproductive traits of autonomous seed production, versatile mating system of self- and cross-pollination, and generalized pollination system might contribute to the species＇ successful invasive capability. The invasiveness was further enhanced by the high and rapid production of achenes, as well as the high percentage, rapid germination rate and high dispersal capability of achenes. It was concluded that in annual or winter-annual weeds, autonomous seed production contributed significantly to the invasiveness of the species.     

Individual variation in dispersal associated behavioral traits of the invasive Chinese mitten crab （Eriocheir sinensis,H. Milne Edwards, 1854） during initial invasion of Lake V~inern,Sweden

Understanding and predicting species range-expansions and biological invasions is an important challenge in modem ecology because of rapidly changing environments. Recent studies have revealed that consistent within-species variation in behavior （i.e. animal personality） can be imperative for dispersal success, a key stage in the invasion process. Here we investigate the composition and correlation of two important personality traits associated with invasion success, activity and boldness, and how they are connected to sex and individual size in a newly colonised population of the Chinese mitten crab Eriocheir sinensis in Lake Vanem, Sweden. We found no effect of sex or size on behavioral expressions orE. sinensis but a clear positive correlation between boldness and activity. In addition, this study generates important baseline data for monitoring behavioral develop ment, and thereby changing ecological impact, of an invading population over time. This has implications for predicting ecological effects of invasive species as well as for managing ecological invasions.     

Hoarding habitat selection of squirrels (Sciurus vulgaris) in Liangshui Nature Reserve, China

This study was conducted during October 2003–April 2004 in the Liangshui National Nature Reserve of the Xiao Xing'an Mountains of Northeast China. Results showed that hoarding behavior of squirrels exhibited selectivity. The preference order of hoarding habitat selection of squirrels is as follows: original Korean pine forest, secondary natural fir forest, artificial fir forest, mix-conifer leaf forest, artificial fallen leaves pine forest, mix-conifer-broadleaf forest, mix-broadleaf forest birch forest, and artificial Korean pine forest. Compared with the existing results, using the cache spots as an index, the order of habitat selection changed, revealing that this research should include more factors, such as pilferage from other animals and secondary dispersal by the squirrels or other species. The Vanderploeg and Scavia selectivity indexes, Wi and Ei, were used to evaluate the use of microhabitat by squirrels in the original Korean pine forest. Results indicated that the squirrels exhibited a significant microhabitat utilization pattern: (1) Squirrels prefer to use the microhabitat in original Korean pine forest with high canopies, the medium shrubby density, and the medium stub density, where pilferage animals are few (Ei > 0.2); (2) Squirrels did not prefer to use the microhabitat in the original Korean pine forest with a low slope degree, high density of fallen logs and stumps, a high herbage coverage, and an abundance of pilferage animals (Ei < ?0.2), and they showed an aversion for a shaded slope (Ei = ?0.5368). The selectivity of microhabitat utilization for the hoarding behavior of squirrels plays an important role in determining the spatial pattern of Korean pine seedlings.     

Hoarding habitat selection of squirrels (Sciurus vulgaris) in Liangshui Nature Reserve, China

This study was conducted during October 2003–April 2004 in the Liangshui National Nature Reserve of the Xiao Xing'an Mountains of Northeast China. Results showed that hoarding behavior of squirrels exhibited selectivity. The preference order of hoarding habitat selection of squirrels is as follows: original Korean pine forest, secondary natural fir forest, artificial fir forest, mix-conifer leaf forest, artificial fallen leaves pine forest, mix-conifer-broadleaf forest, mix-broadleaf forest birch forest, and artificial Korean pine forest. Compared with the existing results, using the cache spots as an index, the order of habitat selection changed, revealing that this research should include more factors, such as pilferage from other animals and secondary dispersal by the squirrels or other species. The Vanderploeg and Scavia selectivity indexes, Wi and Ei, were used to evaluate the use of microhabitat by squirrels in the original Korean pine forest. Results indicated that the squirrels exhibited a significant microhabitat utilization pattern: (1) Squirrels prefer to use the microhabitat in original Korean pine forest with high canopies, the medium shrubby density, and the medium stub density, where pilferage animals are few (Ei > 0.2); (2) Squirrels did not prefer to use the microhabitat in the original Korean pine forest with a low slope degree, high density of fallen logs and stumps, a high herbage coverage, and an abundance of pilferage animals (Ei < ?0.2), and they showed an aversion for a shaded slope (Ei = ?0.5368). The selectivity of microhabitat utilization for the hoarding behavior of squirrels plays an important role in determining the spatial pattern of Korean pine seedlings.     

Molecular phylogeography and evolutionary history of Picea likiangensis in the Qinghai-Tibetan Plateau inferred from mitochondrial and chloroplast DNA sequence variation

The aim of the present study was to examine the phylogeographic and evolutionary history of Picea likiangensis,a dominant species of the conifer forests in the eastern declivity of the Qinghai-Tibetan Plateau. We collected 422 individuals from 42 natural populations of three major varieties classified under this species.In conifers,mitochondrial(mt) DNA and chloroplast(cp) DNA dispersed by seeds or pollen experience very different levels of gene flow.To this end,we examined the sequence variation of two mtDNA fragments(nad5 intron 1 and nad1 intron b/c) and three cpDNA fragments(trnL-trnF,trnS-trnG and nadhK/C).We found that cpDNA probably introgressed from P.purpurea into remote populations of P.likiangensis through long-distance dispersal. Multiple refugia seem to have been maintained for P.likiangensis during the Last Glacial Maximum because the cpDNA and mtDNA haplotypes recovered were fixed in the different regions.Postglacial expansions were only detected at the distributional edges of this species where a single cpDNA or mtDNA haplotype was fixed in adjacent populations.However,genetic imprints of postglacial expansions from these two sets of markers were different in the western and southeastern regions,which may result from the long-distance dispersal of the cpDNA,as well as its fast lineage sorting during intraspecific divergences.Analysis of molecular variance further suggested that genetic differentiation between the three varieties is higher at cpDNA markers than at mtDNA markers,which supports the previous viewpoint that cpDNA markers with a high rate of gene flow may be more effective in delimitating closely related taxa.Together,the results of the present study highlight the evolutionary complexity of a widely distributed species owing to interactions among local and edge expansion,long-distance dispersal,and intraspecific divergences at two sets of DNA genomes with different rates of gene flow.     

Genomic and mitochondrial evidence of ancient isolations and extreme introgression in the four-lined snake

Comparing mitochondrial and genomic phylogenies is an essential tool for investigating speciation processes,because each genome carries different inheritance properties and evolutionary characteristics.Furthermore,mitonuclear discordance may arise from ecological adaptation,historic isolation,population size changes,and sex-biased dispersal.Closely related taxa are expected to experience gene flow;however,this may not be true for insular populations or populations isolated in refugia.The four-lined snake Elaphe quatuorlineata has a fragmented distribution,separating populations of the Italian and Balkan Peninsulas,whereas several insular Aegean populations of significantly smaller body size(Cyclades island group and Skyros Island,Greece)are currently considered distinct subspecies.We constructed the species-tree phylogeny of this species utilizing genome-wide single nucleotide polymorphisms and a gene-tree based on complete cytochrome b sequences,aiming to detect convergence and discrepancies between biparentally and maternally inherited genomes.Population structuring,phylogenetic patterns and migration events among geographically defined lineages supported our hypothesis of isolation in multiple sub-refugia.Where biogeographical barriers did not restrict subsequent dispersal,extensive genetic exchange occurred between mainland Balkan populations.This process has led to the mitochondrial sweep of an ancestral mitolineage that survived only in peripheral(East Greece)and insular populations(North Cyclades and Skyros).The Central Cyclades represent an ancient lineage for both molecular markers that emerged almost 3.3 Mya.Considering their distinct morphology,insular E.quatuorlineata populations should be the future focus of an extensive sampling,especially since the mitonuclear discordance observed in this species could be related to ecological adaptations,such as the island-dwarfism phenomenon.     

Entire solutions in a delayed nonlocal dispersal competitive system

In this paper, we are concerned with the existence of an entire solution in a delayed nonlocal dispersal competitive system. This entire solution converges to two monotone fronts with different speeds, which approach each other from both sides of the x-axis, as t converge to-∞ and then converge to (1,0) as t converges to +∞. Its global dynamic shows the superior species invade the inferior ones from both sides of the x-axis and then the inferior ones become extinct, which is a new invading way. In fact, our conclusions extend this invading way into a more general competitive system. Furthermore, we show several properties of this entire solution.     

Lipidomics as a Principal Tool for Advancing Biomedical Research

Lipidomics,which targets at the construction of a comprehensive map of lipidome comprising the entire lipid pool within a cell or tissue,is currently emerging as an independent discipline at the interf...