红火蚁的社会型及其相关基因Gp-9的研究综述

红火蚁Solenopsis invicta Buren的蚁巢具有2种基本的社会组织形态:单后型和多后型。蚁巢中蚁后的数量是由工蚁和蚁后的基因型共同决定的。红火蚁的Gp-9基因编码一种气味结合蛋白并控制这种社会多态性的表达。Gp-9基因的发现首次证明单个基因在昆虫复杂的社会行为中起关键的作用。从红火蚁的社会型特征、Gp-9基因与不同社会型的关系以及Gp-9基因的相关研究对该领域的研究进展进行综述。     

不同方法对红火蚁社会型鉴定效果的比较

红火蚁Solenopsis invicta Buren的社会型——单蚁后(Monogyne)和多蚁后(Polygyne)型的鉴定方法众多,对于鉴定方法之间的比较较少。为了探究鉴定红火蚁社会型的有效实验方案,本研究对采集自中国南方的红火蚁种群样品进行了生物学观察,并采用了几种常用的方法对样品社会型进行了测定,此外还对比了4种不同DNA聚合酶在实验中的效果。多重PCR技术(Multiplex Polymerase Chain Reaction)、Gp-9 b等位基因扩增两种方法成功率高,能准确鉴定红火蚁社会型。4对同时扩增B、b等位基因的引物成功率不高。实验结果表明,将多重PCR技术、Gp-9 b等位基因扩增,与生物学观察相结合,能更准确地对红火蚁社会型进行鉴定。在PCR实验中选用具有适度保真性和热启动效果的DNA聚合酶能提高红火蚁社会型鉴定的准确性。     

红火蚁雌蚁生殖发育的研究

通过解剖多后型红火蚁Solenopsis invicta Buren雌蛹、有翅雌蚁和脱翅雌蚁,观察了雌蚁内生殖系统的结构和发育进度。结果表明,多后型雌蚁内生殖系统形成于蛹期,其结构与单后型雌蚁存在一定差异。从发育进度来看,虽然雌蚁羽化后其卵巢大小和卵巢管数量仍有一定增长,但蛹期是卵巢大小、卵巢管数量快速增长的阶段;卵子发生始见于羽化后第4d,且卵量随个体发育而快速增加,直至脱翅后第10d达到高峰,随后开始下降;生殖系统的其它结构的变化较小。雌蛹、有翅雌蚁和脱翅雌蚁发育后期的卵巢平均大小分别为1149．23×712．42、1594．88×834．26和1975．60×1303．57μm;而卵巢管数量则分别为62．67、81．33和86．33条。至雌蚁脱翅后10d,卵巢中成熟卵和总卵量分别为20．00±4．62粒和34．00±2．31粒。     

入侵我国红火蚁的三种单倍型

红火蚁Solenopsis invicta Buren是重要的经济害虫,特别是在农业和生态系统危害方面。2004年底在广东和香港的部分地区发现红火蚁入侵。本文用线粒体细胞色素氧化酶Ⅰ（CO Ⅰ）基因对境内的13个种群进行了入侵蚁巢是否独立传入进行了分析。通过对共计28个蚁巢56个体的包含904个碱基的CO Ⅰ基因分析,发现入侵中国的红火蚁中存在3种单倍型。基于未修正的配对序列变异分析表明,单倍型Ⅱ与单倍型Ⅲ之间的变异最小。而香港种群同时具有这三种单倍型,是入侵中国的红火蚁种群中多样性最丰富的地区。这三种单倍型都分别在阿根廷红火蚁种群中有记录。同源性分析显示,中国的红火蚁可能起源于阿根廷或南美洲,而香港可能是所研究种群的第一入侵地点。     

红火蚁对我国一些生物潜在影响的初步分析

通过分析国际上对红火蚁影响生境中其他生物的研究成果,认为红火蚁主要通过以下3种方式危害其他生物:(1)攻击、捕食刚孵化的地栖性卵生动物个体,或者以群体力量捕食昆虫幼虫、成虫等;(2)竞争有限的食物资源,导致其他物种因为缺乏足够食物供给而种群数量减少甚至灭绝;(3)通过叮咬而使得某些动物存活率降低,改变生境,甚至弃巢外逃,或者因为受攻击活动量加大而增加被捕食的几率。同时初步分析在《国家重点保护野生动物名录》中列举的379种野生动物名录中,有22种鸟类(占9.6%)、1种两栖类(占14%)、所有的18种爬行类(占100%)可能因为红火蚁的入侵导致种群数量下降甚至灭绝。     

红火蚁工蚁对绿僵菌侵染蛹的防御行为

研究了红火蚁工蚁感染绿僵菌后在蛹室的行为变化,以及健康工蚁对侵染蛹的行为保护机制.结果表明: 工蚁被绿僵菌侵染后,在蛹室的活动时间逐渐减少,由第1天的103.4 s降至第3天的38.5 s;而且育幼时间占蛹室活动时间的比例也下降,由第1天的13.6%降至第3天的3.5%.当蛹被绿僵菌侵染后,工蚁对侵染蛹的梳理总时间为对照组的5.3倍,每次梳理的平均持续时间为对照组的5.2倍.梳理行为能显著减少侵染蛹的体表分生孢子数量,在无工蚁、2只工蚁和10只工蚁存在条件下,蛹体表平均孢子数分别为103.1、51.6和31.3个.工蚁的存在能抑制蛹体表孢子的萌发,处理20 h后,无工蚁、2只工蚁和10只工蚁存在条件下,蛹体表孢子萌发率分别为95.1%、80.4%和59.9%.蛹的羽化率随着工蚁数量增加显著升高.红火蚁工蚁通过社会行为防御病原真菌侵染蛹的策略为种群的延续和发展提供了保障.     

等位基因特异PCR技术的研究与应用

生物的单核苷酸多态性(Single-nucleotide polymorphism,SNP)具有数量多、分布广、易于分型、稳定性强等优点,很适合于用做分子标记.等位基因特异PCR(Allele-specific PCR,AS-PCR)是根据SNP位点设计3'末端与SNP位点碱基互补或错配的特异PCR引物,通过凝胶电泳等方法检测PCR扩增产物的有或无,从而检测基因型中SNP的一种技术.经过不断地改进与完善,基于SNP的等位基因特异PCR标记已逐渐成为一种快速、简便、低成本、可靠、高通量的检测基因型SNP的方法.本文应用等位基因特异PCR技术,根据小麦TaDREB1基因在旱选10和鲁麦14的120(C→A)SNP成功地开发了一个SNP分子标记,证明了该方法的有效性和可行性.     

应用PCR重组技术构建大肠杆菌分泌型表达载体

应用ＰＣＲ重组技术,对大肠杆菌分泌型表达载体ｐＩＮ－ⅢｏｍｐＡ进行改建,除去原载体的ＨｉｎｄⅢ位点,将信号肽序列末端两个密码子ＣＡＧＧＣＣ改为ＣＡＡＧＣＴ,从而引入一个新的ＨｉｎｄⅢ位点,并在其下游接上一段多克隆位点序列。改建后的载体可用于直接插入外源ＤＮＡ编码序列,表达产物在分泌过程中被切除信号肽而成为天然有活性的蛋白质,操作十分简便。     

四引物PCR扩增反应的单管SNP快速测定法

建立一种在单管中进行单核苷酸多型性 (SNP)快速测定的高效廉价方法 .以人ABCA1基因中的I82 3M为研究对象 ,设计 4种引物进行PCR扩增 ,其中两种引物用于扩增一段含有SNP位点的DNA片段 ,另两种引物为SNP位点特异性引物 ,4种引物在单管中同时进行PCR扩增反应 ,根据延伸产物的长度确定SNP的类型 .为提高SNP测定的特异性 ,在特异性引物的 3′端倒数第 3个碱基引入了一个人为错配碱基 ,使引物的错误延伸率显著降低 ,大大提高了SNP分析的准确性 .实验结果表明 ,所建立的方法简单 ,操作简便 ,可在单管中完成SNP的测定反应 .     

格特隐球菌交配型的多重PCR鉴定

【目的】建立一种基于格特隐球菌α交配型位点内SXI1α基因和a交配型位点内SXI2a基因的多重PCR分析,用于快速鉴定格特隐球菌的交配型。【方法】设计针对格特隐球菌α交配型位点内SXI1α基因部分片段和格特隐球菌a交配型位点内SXI2a基因部分片段的特异性引物,用于多重PCR鉴定格特隐球菌的交配型;并与交配试验以及已报道的扩增α交配型位点的引物MFα、STE12α,及扩增a交配型位点的引物STE20a、STE3a进行扩增效果的比较。【结果】基于SXI1α基因和SXI2a基因的多重PCR分析,准确鉴定所有受试格特隐球菌(包括VGI、VGII、VGIII和VGIV基因型)的交配型,引物STE12α、STE20a和STE3a在常规PCR鉴定中不能鉴定部分菌株的交配型;66.7%的受试菌株不能发生交配,交配试验无法鉴定其交配型。【结论】建立的多重PCR方法明显优于常规PCR或交配试验鉴定。     

Successful establishment of the invasive fire ant Solenopsis invicta in Taiwan: insights into interactions of alternate social forms

Aim Understanding the factors underlying the successful establishment of invasive ant species is critical for developing quarantine strategies to prevent additional invasions as well as for determining how such species overcome the selective pressures in invaded areas. Although several studies have revealed differences in the social organization and population genetics of invasive ants in their native and introduced ranges, few studies have considered the potential interactions between alternate social forms within newly‐invaded areas simply because many invasive ants are characterized as polygyne or unicolonial. Location Taoyuan and Chiayi County, Taiwan. Methods Both social forms (polygyne and monogyne) of the red imported fire ant, Solenopsis invicta, occur in two separately invaded areas in Taiwan (Taoyuan and Chiayi). We employed intensive sampling methods and diagnostic polymerase chain reaction assays to determine the distribution of these two social forms in both infested areas in Taiwan. Results The distribution of social forms differs dramatically between the two infested areas, consistent with different invasion histories regarding the original make‐up of individuals comprising the initial founder group. The Taoyuan population likely was colonized initially by ants of both social forms, with the subsequent spread characterized by continuous outward movement of the two forms, particularly the monogyne form. In contrast, the initial founders of the Chiayi population likely were of the polygyne social form only, suggesting the monogyne social form in this population appeared only recently and likely arose directly from polygyne queens converting to the alternate social form. Main conclusions Our results provide detailed insights into the invasion history of S. invicta in Taiwan and suggest that the distinct reproductive biology of the two social forms may have shaped the current distribution of S. invicta in these infested areas and that the dynamics of two forms may affect the long‐term persistence and potential for spread of this pest ant species.     

Major gene effects on phenotype and fitness: the relative roles of Pgm-3 and Gp-9 in introduced populations of the fire ant Solenopsis invicta

The objective of this study was to disentangle the relative effects of Pgm-3 and Gp-9 and/or other closely linked genes on the phenotypes and reproductive success of queens in introduced (USA) populations of S. invicta. Gp-9 or a closely linked gene(s) was found to have major effects on queen weight, the likelihood that queens shed their wings (a behaviour associated with the onset of reproduction), and the probability that queens are accepted in polygyne (multiple-queen) colonies. Our analyses show that once the effect of Gp-9 genotype is taken into account, Pgm-3 genotype no longer is significantly associated with differences in queen phenotype or the probability of queens being accepted in polygyne colonies. This suggests that the associations of Pgm-3 genotype with weight, wing shedding rate and probability of acceptance by polygyne colonies previously reported in studies that did not control for the effects of Gp-9 are due to the strong linkage disequilibrium that exists between Pgm-3 and Gp-9, or to linkage disequilibria between these and other genes affecting queen phenotype and fitness. Several lines of evidence, including data from the native South American range, suggest that additional cryptic alleles at Gp-9, or additional genes in the same linkage group as Gp-9, must be involved in controlling queen phenotype and the large suite of traits important in determining social organization of S. invicta colonies.     

Molecular evolutionary analyses of the odorant-binding protein gene Gp-9 in fire ants and other Solenopsis species

The fire ant Solenopsis invicta exists in two social forms, one with colonies headed by a single reproductive queen (monogyne form) and the other with colonies containing multiple queens (polygyne form). This variation in social organization is associated with variation at the gene Gp-9, with monogyne colonies harboring only the B allelic variant and polygyne colonies containing b-like variants as well. We generated new Gp-9 sequences from 15 Solenopsis species and combined these with previously published sequences to conduct a comprehensive, phylogenetically based study of the molecular evolution of this important gene. The exon/intron structure and the respective lengths of the five exons of Gp-9 are identical across all species examined, and we detected no evidence for intragenic recombination. These data conform to a previous suggestion that Gp-9 lies in a genomic region with low recombination, and they indicate that evolution of the coding region in Solenopsis has involved point substitutions only. Our results confirm a link between the presence of b-like alleles and the expression of polygyny in all South American fire ant species known to possess colonies of both social forms. Moreover, phylogenetic analyses show that b-like alleles comprise a derived clade of Gp-9 sequences within the socially polymorphic species, lending further support to the hypothesis that monogyny preceded polygyny in this group of fire ants. Site-specific maximum likelihood tests identified several amino acids that have experienced positive selection, two of which are adjacent to the inferred binding-pocket residues in the GP-9 protein. Four other binding-pocket residues are variable among fire ant species, although selection is not implicated in this variation. Branch-specific tests revealed strong positive selection on the stem lineage of the b-like allele clade, as expected if selection drove the amino acid replacements crucial to the expression of polygyne social organization. Such selection may have operated via the ligand-binding properties of GP-9, as one of the two amino acids uniquely shared by all b-like alleles is predicted to be a binding-pocket residue.     

红火蚁多蚁后型种群有效蚁巢局域分布的空间相关性

应用地统计学的方法分析了红火蚁多蚁后型种群有效蚁巢的空间变异规律,建立了多个间隔距离与半方差值的球状模型.对吴川市调查样地的研究表明, 多个样地不同方向上红火蚁有效蚁巢不同间隔距离上的半方差值呈明显规律性变化,表现为随着间隔距离的增大,半方差值增大,具有空间依赖性.其5个球状模型的变程分别为9.1、7.6、23.5、7.5和14.5 m,平均为12.4 m.在这些距离内的抽样空间上任何两点红火蚁有效蚁巢数量间存在相关关系.所建模型块金常数占基台的比例,即空间不连续性较大,分别为0.7034、0.9247、0.4398、1.1196和0.4624,表明红火蚁有效蚁巢分布存在一定的空间随机性和结构性.深圳市的5块样地10个方向上有7个方向半方差值随间隔距离呈明显规律性变化,表现为空间依赖性,变程分别为14.5、11.2、10.8、17.6、11.3、9.9和12.8 m,平均为12.6 m.     

Social chromosome variants differentially affect queen determination and the survival of workers in the fire ant Solenopsis invicta

Intraspecific variation in social organization is common, yet the underlying causes are rarely known. An exception is the fire ant Solenopsis invicta in which the existence of two distinct forms of social colony organization is under the control of the two variants of a pair of social chromosomes, SB and Sb. Colonies containing exclusively SB/SB workers accept only one single queen and she must be SB/SB. By contrast, when colonies contain more than 10% of SB/Sb workers, they accept several queens but only SB/Sb queens. The variants of the social chromosome are associated with several additional important phenotypic differences, including the size, fecundity and dispersal strategies of queens, aggressiveness of workers, and sperm count in males. However, little is known about whether social chromosome variants affect fitness in other life stages. Here, we perform experiments to determine whether differential selection occurs during development and in adult workers. We find evidence that the Sb variant of the social chromosome increases the likelihood of female brood to develop into queens and that adult SB/Sb workers, the workers that cull SB/SB queens, are overrepresented in comparison to SB/SB workers. This demonstrates that supergenes such as the social chromosome can have complex effects on phenotypes at various stages of development.     

深圳市红火蚁婚飞规律研究

本研究利用自制红火蚁Solenopsis invicta Buren收集装置对红火蚁婚飞规律进行研究,结果表明:本试验过程中共观察到婚飞273次,无论大、中、小蚁巢均有有翅蚁婚飞现象;共收集到有翅蚁10 618头,雌雄比为2.1:1;单次婚飞有翅蚁均为雌虫的有167次,均为雄虫的有25次,单次婚飞有翅蚊既有雌虫又有雄虫(雌虫+雄虫)的共81次;同一蚁巢可以发生多次婚飞,同一蚁巢不同次婚飞的有翅蚁性别比也会发生变化;除2009年11月和2010年2月未收集到有翅蚁,其余各月均可观察到有翅蚁婚飞,婚飞最高峰期为2010年4月和5月,其次是2009年6-9月,婚飞次数和收集到的有翅蚁数量成明显的正向相关关系;8:30-15:00均有有翅蚁婚飞,而婚飞高峰期为11:30-13:30,婚飞一般持续30～150 min.婚飞一般发生在雨后晴天或相对低温后气温快速回升以后.     

我国大陆红火蚁入侵扩张趋势长期预测

红火蚁Solenopsis invicta Buren是一种严重危害农林业生产、生命健康、公共安全和生态环境的国际性重大外来入侵害虫。2004年9月中国大陆首次发现红火蚁,2021年12月该蚁已入侵了12个省区近500个县区。本研究根据中国大陆红火蚁入侵发生县区数量变化,结合潜在适生区域评价信息,建立了红火蚁入侵县区数量与入侵时间长度间关系模型,并对入侵县区数量变化趋势作出长期预测。当中国大陆红火蚁潜在入侵县区数量上限分别为1 400、1 500和1 600个时,入侵县区数量与入侵时间长度关系模型分别为N=1400/(1+e^{5.4048-0.1784T})、N=1500/(1+e^{5.4335-0.1757T})和N=1600/(1+e^{5.464-0.1734T})。基于以上模型的分析结果显示,我国红火蚁快速扩散传播从2009-2010年开始,快速扩张期可能持续26～28年,年平均新增县区41～52个/年,预测2035-2037年入侵县区数量增长速率将开始减缓,2...     

Trophallaxis by temporal subcastes in the fire ant, Solenopsis invicta, in response to honey

ABSTRACT. Trophallactic behaviour of temporal subcastes in Solenopsis invicta Buren colonies was studied in two separate experiments. First, radiolabeled honey was presented to small colonies containing larvae, queens and marked workers; radioactivity in the head, thorax and abdomen of each ant was measured after 0.25, 1, 6, 12, 24, 48 and 72 h. The quantity of honey per subcaste was dependent on the total amount of honey collected. As more honey entered the colony, the quantity in foragers, queens and reserves increased more rapidly than that in nurses or larvae. The internal distribution of radioactivity in the head, thorax or abdomen indicated that differences between subcaste members in either the rate of food exchange or digestion existed. In a second experiment behavioural observations were made on marked workers in colonies before and after the presentation of honey. Reserves spent significantly more time engaged in trophallaxis than either foragers or nurses, both as active donors and active receivers. Based on number of encounters, nurses were more likely to receive honey while reserves and foragers were more likely to donate honey. The duration of encounters involving nurses tended to be shorter than those involving reserves or foragers.