黑胸散白蚁幼期不同品级的发育和分化

在黑胸散白蚁Reticulitermes chinensis发育和分化过程中,发现有假工蚁、假若蚁两种虫态。假工蚁由6龄和7龄工蚁转化发育而来,假若蚁由4龄和5龄若蚁转化发育而来。显微测量结果表明,黑胸散白蚁的胚后发育主要包括2个龄期的幼蚁期、6个以上龄期的工蚁期、4个龄期的若蚁期和有翅成虫。在此基础上分析了其他虫态的分化来源,发现兵蚁由3～7龄工蚁分化发育而来,翅鳞型和长翅芽型补充生殖蚁由6龄若蚁转化发育而来,短翅芽型补充生殖蚁由4龄和5龄若蚁转化发育而来,微翅芽型补充生殖蚁既可由4～6龄工蚁转化发育而来,又可由假工蚁和假若蚁转化发育而来,无翅型补充生殖蚁由3～7龄工蚁转化发育而来。提出了黑胸散白蚁群体中不同品级个体的可能分化途径。     

黑胸散白蚁补充型生殖蚁的产生及发育的观察

根据翅和翅芽的有无、长短,把分离群体中培养出的黑胸敌散蚁Reticulitermes chinensis Suyder补充生殖蚁命名为翅鳞型、长翅年型、短翅芽型、微翅芽型和无翅型补充生殖蚁.在工蚁、兵蚁、若蚁组成的群体中,分化较复杂,能培养出多种类型的补充生殖蚁,而在工蚁和兵蚁组成的群体中多数只培养出无翅型补充生殖蚁,少数远能培养出微翅型补充生殖蚁.短翅型、微翅型、无翅型补充生殖蚁需要经历一个后熟期才能产卵.此外,还对分离群体产生补充生殖蚁的频率、数量及初期产卵能力进行了观察.     

黑胸散白蚁新群体的建立及发展规律

经十年的室内配对饲养观察,黑胸散白蚁 Reticulitermes chinensisSnyder初期群体配对后5—10天开始产卵,胚胎发育期36—46天,幼蚁经历两个龄期,各龄8—13天,工蚁是幼蚁经两次蜕皮后分化出来,具有上颚自如活动,头宽0.71mm以上;前兵蚁蜕一次皮发育为兵蚁需经历10—13天,触角14—15节,头宽0.81—0.82mm,大于2龄工蚁,初期巢群最早3个半月左右产生兵蚁.当年配对的产卵期3至4个半月,产卵量16—45粒.饲养7—8年后的群体开始出现若蚁(长翅成虫的幼期).9、10年群体发育成熟即产生长翅成虫.解剖三个成熟群体中一个巢原始蚁王、蚁后均存在,另两巢发现原始蚁王、蚁后均死亡,其中一巢由群体内自行补充上了翅鳞型母蚁1头,无翅补充型生殖蚁1头(较小,性别不清),翅芽型3头.另一巢补充上了无翅型大腹母蚁1头,翅芽型1头.通过室内长期连续饲养观察,对该种白蚁新建群体发育成熟年龄及其内在因素已有一定的了解.     

圆唇散白蚁工蚁生殖可塑性相关的性腺发育和基因表达

【目的】为了探讨圆唇散白蚁Reticulitermes labralis雌性工蚁向补充生殖蚁转化过程中的卵巢发育特征以及卵母细胞从滞育到恢复生长发育的起点。【方法】观察圆唇散白蚁雌性工蚁从3龄-6龄-转化成补充生殖蚁发育过程中的卵巢和卵母细胞动态变化;在若蚁向原始生殖蚁和补充生殖蚁转化的转录组中筛选出与卵母细胞生长期相关的基因表达,利用qRT-PCR方法检测这些基因在工蚁向生殖蚁转化发育过程中的表达水平。【结果】圆唇散白蚁工蚁从低龄向老龄发育过程中卵巢逐渐增大;前补充生殖蚁卵巢长度和宽度分别是工蚁的约2和3倍,而前补充生殖蚁转化为补充生殖蚁之后,卵巢没有显著增大。工蚁转化为前补充生殖蚁之后,卵母细胞大小（长径）和滤泡细胞层厚度仍然没有显著改变;前补充生殖蚁转化成补充生殖蚁之后,卵母细胞大小和滤泡细胞层厚度显著增加。调控卵母细胞生长期发育的6个基因cyclin-dependent kinase 1, cell division cycle protein 20, G2/mitotic-specific cyclin-B3, G2/mitotic-specific cyclin-A, aurora kinase A和serine/threonine-protein kinasepolo在补充生殖蚁中的表达水平极显著增加,分别是前补充生殖蚁的约34, 62, 91, 36, 57和106倍。工蚁转化为前补充生殖蚁之后,仅G2/mitotic-specific cyclin-B3, G2/mitotic-specific cyclin-A和aurora kinase A表达水平显著增高,分别是工蚁的约3, 3和2倍。【结论】圆唇散白蚁工蚁卵巢发育的停滞发生在老龄期,卵母细胞发育的恢复和减数分裂启动从工蚁转化为补充生殖蚁之后开始。     

黑胸散白蚁的分飞成熟年龄及生殖蚁对子代个体分化的抑制作用

实验室配对饲养黑胸散白蚁Reticulitermes chinensis表明,黑胸散白蚁新群体在原始生殖蚁控制下,83.30%的群体在第9年分出了有翅成虫,16.70%的群体在第7年发生有翅成虫分飞,平均分飞成熟年龄为8.67年;由补充生殖蚁控制的群体在第6年即有53.85%的群体发生分飞,第7年有46.15%的群体分飞,平均分飞成熟年龄为6.38年,较原始生殖蚁控制的群体发生分飞平均提前2.29年。初次发生分飞时群体内个体数量前者明显多于后者。研究还发现,群体内补充生殖蚁的数量与分飞发生的早迟关系不大。作者认为在黑胸散白蚁中,原始生殖蚁对补充生殖蚁和若蚁的产生具有较强的抑制作用,而补充生殖蚁对上述品级的分化虽有一定抑制,但不如原始生殖蚁强。认为黑胸散白蚁群体发展速度在品级分化的调节上起到不可忽视的作用,但一定要在生殖蚁分泌外激素的能力开始减弱后才能发挥效应。     

黑胸散白蚁工蚁与工蚁型补充生殖蚁体内抗氧化酶和解毒酶的活性及基因表达变化

【目的】社会性白蚁的工蚁可以转化成补充生殖蚁参与生殖,提高自身适合度。本研究旨在探究工蚁转变成补充生殖蚁后,与氧化应激抗衰老相关的抗氧化酶和解毒酶活性的变化,为揭示生殖蚁的繁殖和抗衰老机制提供参考。【方法】利用生化方法分别测定黑胸散白蚁Reticulitermes chinensis工蚁、工蚁型补充生殖蚁和原始生殖蚁体内的2种抗氧化酶过氧化氢酶(catalase, CAT)和超氧化物歧化酶(superoxide dismutase, SOD)与4种解毒酶酸性磷酸酶(acid phosphatase, ACP)、碱性磷酸酶(alkaline phosphatase, AKP)、羧酸酯酶(carboxylesterase, CarE)和细胞色素P450(cytochrome P450, CYP450)的酶活性;同时利用qRT-PCR检测这些酶对应的基因RsCAT, RsSOD, RsACP, RsCYP450和RsCarE的表达量。【结果】与雌性工蚁相比,黑胸散白蚁工蚁型补充生殖蚁体内的CAT, SOD, ACP, AKP和CarE活性显著上升,分别达到雌性工蚁的5.82, 1.41, 1.39, 2.27和2.70倍,CYP450活性在两品级间没有显著差异;RsCAT, RsSOD, RsACP, RsCarE和RsCYP450的表达量也显著增加。补充生殖蚁体内CAT和ACP活性显著高于原始生殖蚁的,而SOD和AKP活性在两品级间没有显著差异;雌雄补充生殖蚁RsCAT的相对表达量分别是原始生殖蚁的5.68和3.60倍,RsACP的相对表达量分别是原始生殖蚁的81.12和46.72倍。【结论】黑胸散白蚁工蚁由非生殖品级转化为生殖品级以后,体内抗氧化酶和解毒酶的酶活力和基因表达水平显著升高,从一定程度上揭示了生殖品级的抗衰老机制。     

尖唇散白蚁兵蚁和工蚁卵巢和卵子形态特征的比较

兵蚁和工蚁是白蚁中的非生殖品级,兵蚁是由工蚁分化产生。为了探讨兵蚁品级性腺不育的原因以及兵蚁和工蚁性腺发育的差异,采用组织学染色观察与测量方法对尖唇散白蚁Reticulitermes aculabialis Tsai et Hwang的兵蚁和工蚁的卵子发生各阶段进行比较和分析。结果显示:两者性腺发育大小呈极显著性差异(P<0.01),兵蚁与工蚁卵巢横切面面积之比约为1∶7;兵蚁的卵子发生与工蚁相比,仅有卵母细胞的分化期,没有生长期;兵蚁的卵母细胞比工蚁的小,两者的分化期卵母细胞体积之比约为1∶16。该结果表明工蚁向兵蚁转化过程中性腺进一步退化,兵蚁性腺极度退化使其丧失了成为补充繁殖蚁的可能性。该研究结果为兵蚁不能生殖提供组织学上的证据,同时又揭示了兵蚁和工蚁在潜在生殖能力差异方面的组织学基础。     

黑胸散白蚁分离饲养补充型生殖蚁的产生及羽化分飞行为

对黑胸散白蚁Reticulitermes chinensis Snyder成熟群体进行室内自然条件分离饲养观察,结果表明:单品级分离群体和多品级分离群体均能产生补充型生殖蚁,产生补充型生殖蚁的概率与分离群体内的个体数量呈正相关关系,分离时间和气温对产生补充型生殖蚁的历期影响较大,1、4、6、9月分离的群体产生补充型生殖蚁的历期分别为78.50、46.00、32.17、26.00d,经分析差异显著(P<0.05)。分离群体能迅速产出有翅成虫羽化分飞,在分离后2年就可发育进入羽化分飞的成熟年龄,分离时间对产生羽化分飞的历期有一定影响,6月分离的多品级分离群体产生羽化分飞的历期平均为659.3d。单品级翅芽若蚁分离群体可产生羽化分飞,且存在反季节羽化现象。     

圆唇散白蚁补充生殖蚁的类型与建群能力

摘要: 【目的】为了探讨圆唇散白蚁Reticulitermes labralis补充生殖蚁对巢群稳定和发展的作用。【方法】对野外巢群进行调查研究, 及对婚飞成虫通过雌雄配对与补充生殖蚁隔离巢群进行人工饲养的对比研究。【结果】在野外巢群只发现1对原始蚁王蚁后, 而补充生殖蚁的数量最多可达到689头/巢。圆唇散白蚁有3种类型的补充生殖蚁, 即由工蚁转化来的无翅型补充生殖蚁、若蚁转化来的翅芽型补充生殖蚁和末龄若蚁羽化来的拟成虫型补充生殖蚁。实验室条件下婚飞配对群体和隔离群体建群1个月后的存活率分别为64%和96%。建巢初期婚飞配对群体的子代数目增长缓慢, 2个月时的群体数量为6.3±1.54, 10个月时的群体数量也仅为8.4±1.47; 而隔离建群补充生殖蚁2个月时的群体数量为52.4±6.44, 10个月时的群体数量为164.3±20.85, 都高于婚飞配对群体。 此外, 野外巢群的补充蚁后跟原始蚁后一样都具有发达的卵巢。【结论】在圆唇散白蚁中补充生殖蚁是白蚁巢群主要的繁殖力量, 也是建立新巢群的重要繁殖品级。     

黑胸散白蚁下唇腺的解剖和扫描电镜观察

【目的】通过研究黑胸散白蚁Reticulitermes chinensis下唇腺解剖构造及其在不同品级个体间的分化,为进一步探索口交哺和品级分化机制提供参考。【方法】通过显微解剖观察,了解黑胸散白蚁下唇腺的形态构造及其在不同品级个体间的分化;通过扫描电镜观察,了解下唇腺的结构及神经支配;通过饮水实验,研究工蚁饮水及下唇腺囊的贮水功能。【结果】黑胸散白蚁下唇腺是左右对称结构,每侧构造由一个下唇腺腺泡群、一个下唇腺囊及相关的导管组成。每侧导管分别开口于舌基部下方。蚁后的下唇腺最发达,在下唇腺大小、下唇腺囊大小、腺泡大小及腺泡数量4方面均显著高于其他品级个体;兵蚁、工蚁、有翅成虫的下唇腺也较为发达,相互之间这4个参数的差异性不显著。扫描电镜观察发现,工蚁下唇腺腺泡由主导管和分支导管相连,腺泡外侧有神经分布。黑胸散白蚁工蚁有饮水习性,获得的水贮存在下唇腺囊内。【结论】黑胸散白蚁不同品级个体间,蚁后的下唇腺最发达,有翅成虫的下唇腺也比较发达,说明蚁后除行使生殖职能外,还承担交哺育幼等职能。黑胸散白蚁工蚁有饮水习性,下唇腺囊有贮水功能。     

类雄激素受体在尖唇散白蚁繁殖蚁和工蚁卵子发生中的免疫细胞化学表达

为探讨类雄激素受体 (androgen receptor-like,AR-like)在白蚁卵子发生过程中的作用,采用免疫细胞化学方法对尖唇散白蚁Reticulitermes aculabialis雌性繁殖蚁和工蚁卵子发生中的类雄激素受体进行了定位检测。结果发现：繁殖蚁和工蚁卵巢中均有类雄激素受体免疫阳性反应。类雄激素受体在末龄若虫和成虫卵母细胞的分化期和生长期定位于卵母细胞质,而在成虫的卵黄形成期定位于滤泡细胞;在工蚁卵巢中,类雄激素受体定位于分化期和生长期的卵母细胞质,无卵黄形成期。结果提示类雄激素受体在白蚁的卵子发生过程中有重要作用： 工蚁的卵巢发育受抑制,其卵子发生相当于末龄若虫水平,但根据群体的变化又可以发育为补充繁殖蚁,有发育的潜能。     

尖唇散白蚁工蚁、兵蚁和繁殖蚁精子发生的比较研究

为探讨白蚁非生殖品级和生殖品级生殖细胞发育差异,采用组织学染色技术对尖唇散白蚁Reticulitermes aculabialis Tsaiet Hwang繁殖蚁、工蚁和兵蚁的精巢发育以及精子发生进行了显微观察和比较研究。结果发现3个品级间精巢发育的程度差异很大,三者精巢切面面积相对大小之比为:繁殖蚁∶工蚁=1.7∶1;繁殖蚁∶兵蚁=29.3∶1;工蚁∶兵蚁=17.1∶1。繁殖蚁和工蚁精巢管内有精子的形成,工蚁和繁殖蚁精子的发生都经历了精原细胞、初级精母细胞、次级精母细胞、精细胞和精子时期,但工蚁有大量次级精母细胞呈细胞凋亡状态。兵蚁生殖细胞发育仅有精原细胞、初级精母细胞、次级精母细胞,没有精细胞和精子产生。工蚁的生殖细胞显著小于同一时期繁殖蚁的生殖细胞,兵蚁的各时期生殖细胞均极显著小于繁殖蚁同一时期的生殖细胞。研究表明各品级之间生殖功能分化与生殖细胞发育有直接关系,工蚁有转化为补充繁殖蚁和兵蚁的能力;而兵蚁由于精巢极度退化不能产生精细胞和精子,因此是非生殖品级分化的终极形式,不具有转化成补充繁殖蚁或其它品级的能力。     

Compound eye development during caste differentiation in the termite Reticulitermes speratus (Isoptera: Rhinotermitidae)

We morphologically examined postembryonic compound eye development in Reticulitermes speratus (Kolbe) to understand developmental regulation during caste differentiation. The eye primordia were shown to exist from the larval stage. The number of ommatidia and compound eye size greatly increased over the course of imaginal development. Nymphoids (second-form reproductives) possessed a developed compound eye structure on the surface of the cuticle and thick optic nerves, but individual ommatidia were not clearly discriminated. However, in the line of apterous workers and soldiers, although the outer rim of the eye was observed from second-stage workers, there were few morphological differences among instars, including ergatoids (third-form reproductives). Both nymphoids and ergatoids are slightly physogastric and have highly developed reproductive organs. These results suggest that eye development in the apterous line could be strongly arrested and that there is a weak developmental correlation between the eyes and reproductive organs in R. speratus.     

Ovarian development and modes of apoptosis during oogenesis in various castes of the termite Reticulitermes aculabialis

Reproductive division in termites is the most significant biological process that leads to the formation of caste‐specific differences in tasks and status. However, little is known about the mechanism of reproductive division that underlies caste differentiation. In the present study, ovarian development and stage‐specific apoptotic patterns are investigated during oogenesis in reproductive, worker and soldier termites Reticulitermes aculabialis Tsai & Hwang. The results show that the mean lengths of the ovaries of reproductives are two‐fold longer compared with those of workers and six‐fold longer compared with soldiers. By contrast to the reproductives, the process of oogenesis in the workers includes only the oogonium differentiation stage (stage I) and oocyte growth stage (stage II), and oogenesis in the soldiers stops at stage I. Vitelogenic oocytes (stage III) are absent from workers and soldiers. During stage II in the reproductives and workers, the layer of follicle cells has a thickness of 7.56 ± 0.52 and 2.81 ± 0.34 µm, respectively. In addition, there are significant differences in the number and size of the germ cells at the same stage in the various castes. The existence of two apoptotic patterns during oogenesis is demonstrated by the terminal deoxynucleotidyl transferase‐mediated dUTP nick end labelling (TUNEL) assay. First, the majority of the cells showing apoptosis occur at stage I of oogenesis in reproductives, workers and soldiers. Second, DNA fragmentation is demonstrated by TUNEL staining of the follicle cell layers and oocytes at stage II in reproductives. Finally, the proliferation activity of follicle cells in the reproductives is observed by 5‐bromo‐2′‐deoxy‐uridine labelling. The level of oogenesis may explain the significant discrepancies in the reproductive capacity among the reproductives, soldiers and workers. These large discrepancies are controlled by apoptosis during early oogenesis.     

Does lack of intraspecific aggression or absence of nymphs determine acceptance of foreign reproductives in <Emphasis Type="Italic">Macrotermes</Emphasis>?

The rejection or acceptance of a foreign reproductive by an alien colony may not always be as straightforward as cue recognition between worker termites. This paper aims to determine whether adoption of foreign reproductives is caused simply by lack of intraspecific aggression or is contingent on the reproductive status of the host colony. In the fungus-culturing termites, Macrotermes gilvus (Hagen) and Macrotermes carbonarius (Hagen), major workers showed low intraspecific aggression towards non-nestmates irrespective of geographic distance between source colonies. Our results indicated that workers were hardly aggressive towards non-nestmates. In royal cell-swapping experiments, both species responded in a similar way: (1) in host colonies with nymphs present, the foreign reproductives were rejected; while (2) in host colonies without nymphs the foreign reproductives were either accepted and breeding resumed or the host colonies died eventually. Workers from the host colonies preferentially maintained offspring nymphs from which adultoid replacement reproductives develop rather than accepting foreign reproductives. There is no fitness gain for the queenless workers in accepting foreign reproductives; however, there is overall benefit to the newly born population.     

Workers do not mediate the inhibitory power of queens in a termite, <Emphasis Type="Italic">Reticulitermes speratus</Emphasis> (Isoptera,Rhinotermitidae)

In social insects, the caste systems are based on reproductive division of labor; queens specialize in reproduction and workers primarily maintain the colony. Recently, a volatile pheromone containing n-butyl-n-butyrate and 2-methyl-1-butanol was identified as a termite queen pheromone that inhibits the differentiation of female neotenic reproductives (secondary queens). Although this volatile inhibitory pheromone regulates caste differentiation directly, the method by which it reaches members without direct contact with the queen in large colonies is not well understood. Therefore, additional mechanisms of indirect communication must exist, such as worker-mediated queen signal transport. We found that workers exposed to female reproductives did not mediate queens’ inhibitory signal in a termite Reticulitermes speratus. The experiment assessed worker transfer from direct to indirect contact groups and determined that the differentiation of new female reproductives in the indirect contact groups was not influenced by the direct contact groups, whereas direct contact with functional female reproductives and artificial queen pheromone did suppress neotenic differentiation. This suggests that worker transfer of the queen signal is unlikely and that for colony-wide inhibition direct contact by the majority of infertile members with reproductives or eggs, which emit the same volatiles as female reproductives, is necessary within a certain time interval.