Sociobiology最新文献

筛选
英文 中文
Effects of Eight Years of Collecting on the Persistence of Liometopum apiculatum Ant Nests in Rangelands of Charcas, San Luis Potosí, Mexico 八年采集对墨西哥圣路易斯波托西州查尔卡斯牧场中 Liometopum apiculatum 蚂蚁巢持久性的影响
IF 0.9 4区 农林科学
Sociobiology Pub Date : 2024-05-15 DOI: 10.13102/sociobiology.v71i2.10082
Julio César Zavala-Sánchez, J. A. Reyes-Agüero, Priscila Lara-Juárez, Pedro Castillo Lara, Alicia Grajales-Lagunes, Rogelio Aguirre-Rivera
{"title":"Effects of Eight Years of Collecting on the Persistence of Liometopum apiculatum Ant Nests in Rangelands of Charcas, San Luis Potosí, Mexico","authors":"Julio César Zavala-Sánchez, J. A. Reyes-Agüero, Priscila Lara-Juárez, Pedro Castillo Lara, Alicia Grajales-Lagunes, Rogelio Aguirre-Rivera","doi":"10.13102/sociobiology.v71i2.10082","DOIUrl":"https://doi.org/10.13102/sociobiology.v71i2.10082","url":null,"abstract":"In Mexico, the pupae of the reproductive castes of the ant Liometopum apiculatum, escamoles, are highly valued in traditional and gourmet cuisine in the country’s central region. Escamoles are collected during the dry season of the year. The recommended collecting process is to open the ant nest by removing soil until the rearing chamber and the trabeculae with attached escamoles are found. A well-managed ant nest can be collected repeatedly for approximately 12 to 40 years. In Charcas municipality, San Luis Potosí, Mexico, 400 ant nests were located and checked under two land tenure conditions: the Laguna Seca private ranch and the Pocitos communal ejido. The exploitation of escamoles on both tenures was characterized by recording the number of dead and live ant nests. This work evaluated the condition of the ant nests registered in 2012 after eight years. The hypothesis was that ant nests’ survival would be greater in the private than in the communal land. The percentage of living ant nests on the ejido decreased by 35.67%. In contrast, on the ranch, it was 26.88%. The percentage of relocated ant nests was lower on the ejido, 37.43%, compared to the ranch, which was 48.1%. The number of dead ant nests on the ejido increased to 33.51% and on the ranch 15.0%. As predicted by the hypothesis, ant nest survival was higher on the private ranch than on the communal ejido lands because of stronger control of the extraction process.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141128074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Morphological and Histological Structure of Adexinal Glands of some Solitary Bee Species (Hymenoptera – Apoidea) 一些独居蜂种(膜翅目 - Apoidea)的肛门腺的形态学和组织学结构
IF 0.9 4区 农林科学
Sociobiology Pub Date : 2024-05-09 DOI: 10.13102/sociobiology.v71i2.10405
Kariman M. Mahmoud, Mohamed A. Shebl
{"title":"Morphological and Histological Structure of Adexinal Glands of some Solitary Bee Species (Hymenoptera – Apoidea)","authors":"Kariman M. Mahmoud, Mohamed A. Shebl","doi":"10.13102/sociobiology.v71i2.10405","DOIUrl":"https://doi.org/10.13102/sociobiology.v71i2.10405","url":null,"abstract":"Solitary bees are diverse and very important for plant and crop pollination. They are extensively studied taxonomically, but little is known about their anatomy and physiology compared to honey bees. Dufour’s gland is important for many physiological functions in social and solitary bees. The present study addresses the morphological and histological structure of Dufour’s gland in ten bee species representing bee families Andrenidae, Colletidae, Halictidae, Melittidae, Megachilidae, and Apidae. Results indicated that the shape and size of the glands tend to differ from one species to the other. However, on histological bases, the intern seems to be the same among the secretion cell types. The gland varied in length and size in the studied species, probably due to nesting behavior differences: ground and cavity nesting. Further studies are needed to clarify the different secretions produced by Dufour’s gland and their functions in each species.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141129028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Diversity and Species Composition of Ants in Urban and Suburban Environments in Bejaia City (Algeria) 贝贾亚市(阿尔及利亚)城市和郊区环境中蚂蚁的多样性和物种组成
IF 0.9 4区 农林科学
Sociobiology Pub Date : 2024-05-09 DOI: 10.13102/sociobiology.v71i2.9698
Nadjet Laakel, L. Aissat, Leila Bounab, Cilia Yahiaoui
{"title":"Diversity and Species Composition of Ants in Urban and Suburban Environments in Bejaia City (Algeria)","authors":"Nadjet Laakel, L. Aissat, Leila Bounab, Cilia Yahiaoui","doi":"10.13102/sociobiology.v71i2.9698","DOIUrl":"https://doi.org/10.13102/sociobiology.v71i2.9698","url":null,"abstract":"We conducted an ant inventory in urban and suburban spaces in Bejaia city to deal with this need for more information about ant biodiversity in the Algerian urban environment. The two methods, hand collecting and pitfall traps, are carried out 24 days in three months (May, June, and July) of 2022. In the urban habitats, 2,653 ant individuals were collected, comprising ten species, six genera and three subfamilies. In the suburban habitats, 6,706 ant specimens were collected, comprising 19 species, 11 genera, and three subfamilies. The most abundant subfamilies in both urban and suburban habitats are Formicinae, followed by Myrmicinae and Dolichoderinae. The results showed that suburban habitats are more diversified (H’= 1.72) than urban habitats (H’= 1.25). The equitability values for suburban and urban habitats are moderate, with 0.58 and 0.54, respectively. The Jaccard similarity index value is 0.45, indicating an essential turnover of ant species between urban and suburban habitats. The ant community’s composition differed between sampled sites (NMDS, Stress = 0.013). The average dissimilarity (as per SIMPER) was 90.37%. Four species (T. simrothi, L. cf. grandis, P. cicatricosa, and L. myops) contributed to 70% of the differences between sites of urban and suburban habitats.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141129020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Lipid Food Preference and Transportation Using Tools by an Indian Ant Species Monomorium pharaonis (Hymenoptera: Formicidae): A Field Study 一种印度蚁(膜翅目:蚁科)的脂质食物偏好和工具运输:野外研究
4区 农林科学
Sociobiology Pub Date : 2023-10-09 DOI: 10.13102/sociobiology.v70i4.9167
Ritika Sarkar, Sarmistha Banik, Ranajit Karmakar
{"title":"Lipid Food Preference and Transportation Using Tools by an Indian Ant Species Monomorium pharaonis (Hymenoptera: Formicidae): A Field Study","authors":"Ritika Sarkar, Sarmistha Banik, Ranajit Karmakar","doi":"10.13102/sociobiology.v70i4.9167","DOIUrl":"https://doi.org/10.13102/sociobiology.v70i4.9167","url":null,"abstract":"Besides proteins and carbohydrates, the Pharaoh ant (Monomoroium pharaonis) prefers lipid foods especially when it becomes limiting in the colony. We used four different food-grade lipids such as mustard oil, sunflower oil, coconut oil and butter for seven consecutive days for a specified time frame (11.15 hr - 14.15 hr). There was a specific time zone in which the highest number of ants accumulated at all four food baits with varying peak values. Sunflower oil was the most preferred food, and mustard oil showed the lowest like. The differential number of ants in all four lipid food baits under observation can be attributed to the physical features and nutrient content. We also noted an interesting feature of the foraging activity: the major role of gathering and transporting food was performed primarily by two castes, intermediate and large, among the four distinct foraging castes. Most tools used in the present investigation were <0.5mm and of naturally available sand particles. They used the smallest tools more often as compared with the size of the other two categories. Our ant (M. pharaonis) transported only the butter-soaked smallest tools back to the nest. M. pharaonis used the smallest tools more often and this could be because the particular-sized tools were efficiently managed by the ant species under study. Our ants transported only the butter-soaked smallest tools back to the nest. It is revealed that butter was the most important lipid food for the particular ant colony of M. pharaonis.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135143158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
First Records of the Exotic Ant Strumigenys rogeri, Emery 1890 in Brazil 外来蚂蚁Strumigenys rogeri的最早记录,1890年在巴西
4区 农林科学
Sociobiology Pub Date : 2023-10-09 DOI: 10.13102/sociobiology.v70i4.9886
Esperidião Alves dos Santos-Neto, Elmo Borges A. Koch, Alexandre Arnhold, Jacques H. Charles Delabie
{"title":"First Records of the Exotic Ant Strumigenys rogeri, Emery 1890 in Brazil","authors":"Esperidião Alves dos Santos-Neto, Elmo Borges A. Koch, Alexandre Arnhold, Jacques H. Charles Delabie","doi":"10.13102/sociobiology.v70i4.9886","DOIUrl":"https://doi.org/10.13102/sociobiology.v70i4.9886","url":null,"abstract":"Strumigenys Smith, 1860 is a megadiverse ant genus with 858 species distributed worldwide. These ants forage and nest in leaf litter, rotten wood, dried leaves or twigs and are specialized predators. Here we present the first records of the pantropical Strumigenys rogeri Emery, 1890 in Brazil. The information was obtained from specimens conserved in the Formicidae Collection of the Cocoa Research Center. We recovered data of occurrence of S. rogeri in six locations in southern Bahia, Brazil. The specimens were found in remnants, secondary growths or agroforest areas within the Atlantic Brazilian rainforest biome. Interestingly, areas of cocoa agrosystems shaded with Eritryna legume trees seem allowing this ant to be relatively easy to find. It is reasonable to think that many specimens of S. rogeri were accumulated in entomological collections throughout Brazil or were misidentified due to the complicated taxonomy of the genus.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135146620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Ants Sleep, Plants do not: The Variation in Species’ Activity Influences the Topology of Interaction Networks 蚂蚁睡觉,植物不睡觉:物种活动的变化影响相互作用网络的拓扑结构
4区 农林科学
Sociobiology Pub Date : 2023-10-09 DOI: 10.13102/sociobiology.v70i4.9283
José Eneas Schramm Júnior, Gabriela S. Oliveira, Tamires B. Santos, Gilberto Marcos de M. Santos
{"title":"Ants Sleep, Plants do not: The Variation in Species’ Activity Influences the Topology of Interaction Networks","authors":"José Eneas Schramm Júnior, Gabriela S. Oliveira, Tamires B. Santos, Gilberto Marcos de M. Santos","doi":"10.13102/sociobiology.v70i4.9283","DOIUrl":"https://doi.org/10.13102/sociobiology.v70i4.9283","url":null,"abstract":"The emergence of graph theory allowed using the complex network approach to aggregate detailed information about interactions between species. Although the use of the complex network approach has improved the understanding about community structuring, few aspects such as the temporal variation in the species’ activity pattern in the networks’ topology were explored so far. The current study used the ecological network approach to investigate ants interacting in the extrafloral nectary (EFN) of plants in order to test the hypothesis that the temporal variation in the foraging behavior of these animals affects the networks’ topology. In order to assess the temporal effect on the interaction networks, 24-hour collections divided in two 12-hour shifts (day and night) were performed in 20 plots, thus totaling 288 collection hours over 6 months. The ant-plant interaction networks presented similarity among the topological metrics assessed throughout the day. Different ant species presented distinct foraging times. Thus, two modules referring to the day and night shifts emerged from the network and presented specific species at each foraging shift. On the other hand, the plants kept on providing the resource (active EFNs) throughout the day. The results found in the current study have shown that ecological networks keep their structures constant; however, the ecological processes ruling these networks can better respond to the effects caused, for example, by the temporal variation in species’ activity. Therefore, it is worth always taking into consideration the importance of ecological processes at the time to analyze interactions in the nature.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Record of an Ectoparasitic Fungus on Eggs of the Neotropical Termite Nasutitermes corniger (Blattaria, Isoptera, Termitidae) 一种新热带白蚁(白蚁亚目,等翅目,白蚁科)卵外寄生真菌的记录
4区 农林科学
Sociobiology Pub Date : 2023-10-09 DOI: 10.13102/sociobiology.v70i4.9592
Ana Maria Costa-Leonardo, Vanelize Janei
{"title":"Record of an Ectoparasitic Fungus on Eggs of the Neotropical Termite Nasutitermes corniger (Blattaria, Isoptera, Termitidae)","authors":"Ana Maria Costa-Leonardo, Vanelize Janei","doi":"10.13102/sociobiology.v70i4.9592","DOIUrl":"https://doi.org/10.13102/sociobiology.v70i4.9592","url":null,"abstract":"Insects and fungi are abundant in many environments and often interact. However, little information exists on the fungal infestation of insect eggs. Here, we report an entomogenous fungus similar to Hormiscioideus filamentosus (Blackweel &amp; Kimbrough, 1978) infesting eggs of the termite Nasutitermes corniger (Motschulsky, 1855). The fungus arises from egg chorion and has long and simple filaments. The small haustorial cells infiltrate the egg chorion and the fungal thalli number varies from two to ten. Future studies will elucidate the infestation levels of termite eggs by this entomogenous fungus in the Neotropical region and its effects on termite colonies.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Step-by-step Dissection Protocol of Apicotermitinae Worker (Blattaria: Isoptera) 顶白蚁科工蜂分步解剖规程(白蚁目:等翅目)
4区 农林科学
Sociobiology Pub Date : 2023-10-09 DOI: 10.13102/sociobiology.v70i4.8503
Rayssa Almeida-Azevedo, João Alves-Oliveira, José Wellington Morais, Elizabeth Franklin, Renato Almeida de Azevedo
{"title":"Step-by-step Dissection Protocol of Apicotermitinae Worker (Blattaria: Isoptera)","authors":"Rayssa Almeida-Azevedo, João Alves-Oliveira, José Wellington Morais, Elizabeth Franklin, Renato Almeida de Azevedo","doi":"10.13102/sociobiology.v70i4.8503","DOIUrl":"https://doi.org/10.13102/sociobiology.v70i4.8503","url":null,"abstract":"Apicotermitinae are soldierless termites highly abundant in tropical forests. The taxonomy of this subfamily is based on characters of worker cast and winged forms when present. However, the procedures necessary to dissect termite workers to observe their external and internal morphological characteristics are not well detailed in any study. Here, we describe a step-by-step protocol for worker dissection of soldierless termite species. We suggest the use of Polyvinyl Alcohol (PVA) for cleaning and visualization of the gizzard and enteric valve, and glycerin to remove tergites and sternites and describe in detail the dissection of the gizzard and enteric valve, and how visualize the insertion of Malpighian tubules.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135143168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Reviewing Social Facilitation in Insects Over the Past 30 Years 回顾过去30年昆虫的社会促进作用
4区 农林科学
Sociobiology Pub Date : 2023-10-09 DOI: 10.13102/sociobiology.v70i4.9210
Andrea A. Fonseca, Conceição Aparecida dos Santos
{"title":"Reviewing Social Facilitation in Insects Over the Past 30 Years","authors":"Andrea A. Fonseca, Conceição Aparecida dos Santos","doi":"10.13102/sociobiology.v70i4.9210","DOIUrl":"https://doi.org/10.13102/sociobiology.v70i4.9210","url":null,"abstract":"Social facilitation is a phenomenon in which individuals from a group show behavioral changes due to the presence of other organisms of the same species. This happens through group interaction between these individuals, later increasing in frequency or intensity. Social facilitation studies began with humans but later extended to other species, including insects. The concepts of social facilitation in insects developed over the last 30 years are reviewed here. To that end, bibliographic searches were carried out to determine whenthe term social facilitation first emerged, how it was described in the research, where and when it was applied, and how the concept is currently employed. There has been, however, a steady decrease in the number of published texts conceptualizing the term social facilitation during the last three decades. Nevertheless, the terms emergent behavior, collective behavior, and informationexchange enabled expansion of the survey on social facilitation, indicating that study in the area remains broad. The orders Blattodea (cockroaches and termites) and Hymenoptera (ants, wasps, and bees) were the most represented among the surveyed publications, indicating the occurrence of social facilitation due to eusociality. Eusocial organisms demonstrate unique social interactions, which makes them likely objects of future social facilitation studies.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135143170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
First Record of the Introduced Ant Myrmica specioides In the Eastern United States 美国东部引进金蚁物种的首次记录
4区 农林科学
Sociobiology Pub Date : 2023-10-09 DOI: 10.13102/sociobiology.v70i4.9153
Sämi Schär, Roger Vila, Mattia Menchetti
{"title":"First Record of the Introduced Ant Myrmica specioides In the Eastern United States","authors":"Sämi Schär, Roger Vila, Mattia Menchetti","doi":"10.13102/sociobiology.v70i4.9153","DOIUrl":"https://doi.org/10.13102/sociobiology.v70i4.9153","url":null,"abstract":"The ant Myrmica specioides Bondroit, 1918 (Hymenoptera: Formicidae) is first reported from the Eastern United States. This species is native to the West Palearctic region and has previously been known as an introduced species in Northwestern North America. It was found 2013 in the Boston metropolitan area. The species was identified by morphometric comparison to type specimens and DNA-barcoding. The distribution and invasive potential of M. specioides are discussed.","PeriodicalId":21971,"journal":{"name":"Sociobiology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135141253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信