黑翅土白蚁与其它二种白蚁种群间的相容性

将黑翅土白蚁Odontotermes formosanus(Shiraki)与另外2个种群的白蚁按一定比例放置于同一培养皿中观察其斗争情况,研究黑翅土白蚁与台湾乳白蚁Coptotermes formosanus(Shiraki)和黑胸散白蚁Reticulitermes chinensisSnyder的相容性。结果表明,实验一开始,双方的工蚁和兵蚁都立即进入激烈的嘶咬斗争,在不同配比下,开始5min内的斗争次数均在40次左右,5h后开始5min内的斗争次数陡然下降,几乎不发生争斗。各种群白蚁在其数量占优势的情况下均表现出显著的斗争优势;而在双方数量相当时,黑翅土白蚁工蚁的斗争能力明显强于另外2个种群的工蚁。结果表明,自然界中不可能出现黑翅土白蚁与家白蚁和黑胸散白蚁群体的偶然性融合,黑翅土白蚁很可能在其群体建立的地区中占据优势。     

三种白蚁的头胸部及消化道结构特征比较

【目的】白蚁具有降解木质纤维素的能力,主要场所在消化道内,因此消化道形态结构的研究具有重要意义。【方法】本文对采自河南省的3种白蚁(平额散白蚁Reticulitermes planifrons Li et Ping、湖南散白蚁Reticulitermes hunanensis Tsai et Peng和双工土白蚁Odontotermes dimorphus Li et Xiao的兵蚁和工蚁头胸部特征及其消化道结构进行了比较。【结果】两种散白蚁兵蚁的头壳、后颏和上颚没有明显差异,但与双工土白蚁差异显著。3种白蚁工蚁的前肠、后肠及消化道平均长度均大于兵蚁,且差异显著(P<0.05),而中肠的差异不显著;双工土白蚁的肠道总长度工蚁/兵蚁比值(1.4倍)大于两种散白蚁(1.1倍);除了嗉囊和囊形胃外,两种散白蚁工蚁的其余消化道各段差异显著(P<0.05),与双工土白蚁相比差异也显著。【结论】工蚁的消化道比兵蚁发达,散白蚁的消化道结构与土白蚁有较大不同,这些结果与工蚁和兵蚁的社会分工有关,同时也表明高等白蚁与低等白蚁相比不仅是采食习惯的差别,自身消化系统结构与分区也有较大不同,并为白蚁的生物防治和生物质资源利用提供了资料。     

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。     

八种白蚁的兵蚁和工蚁消化道形态比较研究(等翅目)

为探讨白蚁消化道形态品级差异及其系统学意义,对4个科8种白蚁兵蚁和工蚁的消化道进行比较形态学研究.结果表明:低等白蚁的兵蚁和(拟)工蚁形态较为相似,高等白蚁的兵蚁与工蚁局部特征存在明显差异.由低等到高等兵蚁和工蚁消化道各部分差异呈增多趋势.前、中、后肠占消化道的百分比在山林原白蚁Hodotermopsis sjoest...     

保幼激素类似物对白蚁的作用研究进展

本文介绍了保幼激素类似物对白蚁的影响,包括诱导前兵蚁、兵蚁和一些中间品级(形态畸形)的产生、抑制白蚁的取食、减少或消除白蚁的共生原生动物群、对白蚁产生不同水平的急性和慢性毒性、抑制工蚁蜕皮以及繁殖蚁建立新群体等方面的影响,其中最主要影响是诱导前兵、兵蚁和一些中间品级的产生破坏了白蚁群体品级比例的平衡性或完整性.因此,保幼激素类似物可用于白蚁的防治,并在田问防治散白蚁和乳白蚁均取得了较好的防治效果,并探讨了应用保幼激素类似物防治白蚁的潜力与前景.     

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。     

台湾乳白蚁种群兵蚁量度特征变异及其分类学意义分析

台湾乳白蚁Coptotermes formosanus是我国南方木材及其建筑结构最主要的有害白蚁,也是世界重要的入侵性物种。台湾乳白蚁兵蚁品级的量度特征是其描述鉴定的重要依据,本文对台湾乳白蚁兵蚁主要量度特征数据进行了整合,并就台湾乳白蚁11个地理种群兵蚁品级的主要量度特征进行了比较,探讨了台湾乳白蚁相应量度特征的分类学意义。     

台湾乳白蚁行为多型的研究

本文对台湾乳白蚁的打洞挖掘行为、取水行为、修饰行为和交哺行为进行了比较详细的定量分析,探讨了年龄和品级对台湾乳白蚁群体中行为多型的影响。实验结果表明大（老）龄工蚁承担了台湾乳白蚁群体内大多数的任务,对台湾乳白蚁群体的维持具有重要意义。另外品级也是影响台湾乳白蚁群体内劳动分化的一个重要因素。在营养交哺方面,若蚁尚不具备完好的取食行为,是群体中营养交哺的受益者,而兵蚁在台湾乳白蚁群体中占据着较重要的地位,享受着营养物质优先供应的特殊权利。     

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。     

Differential susceptibility of subterranean termite castes to entomopathogenic nematodes

We examined the attachment and infectivity of two entomopathogenic nematode species, Steinernema carpocapsae and Heterorhabditis indica, on soldiers and workers in two subterranean termite species, Coptotermes formosanus and C. vastator. In attachment tests with S. carpocapsae, more nematodes attached to soldiers of C. formosanus and C. vastator in the absence of workers compared to soldiers that were in the presence of workers. In tests with soldiers alone, workers alone, and mixture of equal numbers of workers and soldiers, soldiers in the mixed groups had lower mortality than soldiers alone after 1 and 4 days for both termite species. Exposure of small groups of either termite species to S. carpocapsae resulted in higher mortality of soldiers after 1 and 4 days post exposure. Mortality in soldiers alone exposed to H. indica was not significant compared to mortality in mixed groups at 1 day exposure, but was significant after 4 days. In concentration-mortality tests, a significant two-way interaction existed between nematode concentration and termite caste for C. formosanus exposed to S. carpocapsae for 1 and 4 days. A significant effect of nematode concentration was found for C. vastator exposed to H. indica for 1 day. This termite species had lower mortality when exposed to H. indica after 1 and 4 days compared to C. formosanus. At 4 days post exposure to H. indica, the effects of nematode concentration and termite caste were significant. Steinernema carpocapsae caused higher mortality than H. indica, but mortality of workers was higher when exposed to H. indica. Soldiers of both species experienced rapid mortality when exposed to S. carpocapsae, whereas soldiers of C. vastator experienced lower mortality when exposed to H. indica. Thus, our results show that when soldiers alone or workers alone are exposed to the nematodes, there is a differential susceptibility of soldiers and workers to nematode infection with soldiers being more susceptible than workers. In a mixed group of soldiers and workers or workers alone, it appears that grooming behavior of the workers serves as a mechanism to reduce nematode infection of soldiers and workers. The reason for this differential response to nematode infection is that soldiers do not exhibit grooming behavior.     

Regulation of juvenile hormone titers by soldiers in the Formosan subterranean termite, Coptotermes formosanus

In field collections of the Formosan subterranean termite Coptotermes formosanus, soldiers averaged less than 10%. The proportion of soldiers increased to about 25% or higher when termites were kept in the laboratory, as did the juvenile hormone III (JH III) titers for both workers and soldiers. In laboratory experiments with a proportion of soldiers 25% or higher, very few new pre-soldiers were formed and the JH titer in existing soldiers remained constant. On the contrary, workers from groups containing less than 25% soldiers formed more pre-soldiers. In such cases, both workers and soldiers showed higher JH titers. Newly formed soldiers also had higher JH titers than older soldiers. It is speculated that populations containing higher soldier proportions inhibit further soldier differentiation, eventually holding the JH titers under the threshold or suppressing the activity of corpora allata resulting in lower JH titers in workers.     

Physical contact between soldier and worker is essential in soldier self-regulation of Coptotermes formosanus (Isoptera, Rhinotermitidae)

In a termite society, the soldier proportion is regulated at a species-specific level with a seasonal fluctuation. A feedback mechanism in soldier proportion regulation is well recognized, while the proximate means by which the presence of soldiers inhibits the new soldier formation from workers remains mostly elusive. In the present study, some possible means for this inhibition were tested with the Formosan subterranean termite, Coptotermes formosanus Shiraki. The results showed that neither soldier-originated volatiles nor non-volatile chemicals without physical contact were responsible for the inhibition of new soldier formation. The essentiality of physical contact between workers and soldiers in soldier regulation was established. However, by physical contacts, as the soldier-replacement experiment showed, workers could not individually recognize or “count” soldiers to maintain a set soldier proportion. The possible feedback mechanisms for soldier regulation are discussed.     

Behavioral Interactions Between <Emphasis Type="Italic">Aphaenogaster rudis</Emphasis> (Hymenoptera: Formicidae) and <Emphasis Type="Italic">Reticulitermes flavipes</Emphasis> (Isoptera: Rhinotermitidae): The Importance of Physical Barriers

Predation pressure from ants is a major driving force in the adaptive evolution of termite defense strategies and termites have evolved elaborate chemical and physical defenses to protect themselves against ants. We examined predator–prey interactions between the woodland ant, Aphaenogaster rudis (Emery) and the eastern subterranean termite, Reticulitermes flavipes (Kollar), two sympatric species widely distributed throughout deciduous forests in eastern North America. To examine the behavioral interactions between A. rudis and R. flavipes we used a series of laboratory behavioral assays and predation experiments where A. rudis and R. flavipes could interact individually or in groups. One-on-one aggression tests revealed that R. flavipes are vulnerable to predation by A. rudis when individual termite workers or soldiers are exposed to ant attacks in open dishes and 100% of termite workers and soldiers died, even though the soldiers were significantly more aggressive towards the ants. The results of predation experiments where larger ant and termite colony fragments interacted provide experimental evidence for the importance of physical barriers for termite colony defense. In experiments where the termites nested within artificial nests (sand-filled containers), A. rudis was aggressive at invading termite nests and inflicted 100% mortality on the termites. In contrast, termite mortality was comparable to controls when termite colonies nested in natural nests comprised of wood blocks. Our results highlight the importance of physical barriers in termite colony defense and suggest that under natural field conditions termites may be less susceptible to attacks by ants when they nest in solid wood, which may offer more structural protection than sand alone.     

Juvenile hormone III titers and regulation of soldier caste in coptotermes formosanus (Isoptera: Rhinotermitidae)

Juvenile hormone (JH) is an important growth hormone in insects that has also been implicated in caste determination in termites. Gas chromatography-mass spectrometry was used to establish that the JH in the Formosan subterranean termite, Coptotermes formosanus Shiraki, is JH III. JH III titers were measured in workers, pre-soldiers, and soldiers from samples collected from the field. The average titers of JH III in workers and soldiers were about 13 and 25 pg mg(-1), respectively. However, pre-soldiers contained a significantly higher amount, 596 pg mg(-1). As expected, treatment of workers with a JH-analogue, methoprene, triggered rapid formation of pre-soldiers. However, these pre-soldiers had a very low JH III titer (62 pg mg(-1)). It appears that the application of JHA, while inducing pre-soldier formation, does not increase the endogenous JH III titer. The titer, however, increased as the pre-soldiers aged and before transforming into soldiers.     

Intra- and interspecific agonistic behavior of the subterranean termite Microcerotermes crassus (Isoptera: Termitidae)

The aim of our study was to investigate the intra- and interspecific agonistic behaviors exhibited by the worker and soldier castes of the subterranean termite Microcerotermes crassus Snyder (Isoptera: Termitidae). Aggression between M. crassus colonies from different field locations and also against three termite species--Coptotermes gestroi (Wasmann), Globitermnes sulphureus Haviland, and Odontotermes sp.--were observed in the laboratory. Termite responses were tested in paired combination of castes (soldiers versus soldiers, soldiers versus workers, and workers versus workers) consisting of 10 individuals each. Significant agonistic behaviors were observed only in encounters between pairings of different termite species. M. crassus was aggressive toward individuals from different species but not toward individuals from different M. crassus colonies. Mortality of M. crassus reached 100% in most of the interspecific encounters. However, no or low mortality was recorded in the intraspecific pairings.     

Insecticide susceptibility in Coptotermes formosanus and Reticulitermes virginicus (Isoptera: Rhinotermitidae).

Lethal time to mortality responses were established for eight insecticides against workers and soldiers of the Formosan subterranean termite, Coptotermes formosanus Shiraki, and workers of Reticulitermes virginicus (Banks). There were significant differences in the tolerance ratios between workers of C. formosanus colonies to all toxicants tested except fipronil. One colony was 16 times more tolerant than another to deltamethin. C. formosanus soldiers had significant differences in tolerance ratios among colonies exposed to all toxicants except chlorpyrifos. Methoxychlor, permethrin, deltamethrin, and fipronil did not kill soldiers from two, one, one, and three colonies, respectively, within 8 h. Seventy-five percent of R. virginicus colonies were significantly less susceptible than the most susceptible colony to chlordane, methoxychlor, chlorpyrifos, cypermethrin, and fipronil, with 50% of the colonies less susceptible to permethrin and bendiocarb. In 50% of C. formosanus colonies the worker lethal time curves displayed substantial flattening in response to permethrin, and deltamethrin. Lethal time curses for C. formosanus soldiers exposed to chlordane, chlorpyrifos, permethrin, cypermethrin, deltamethrin, and bendiocarb showed substantial flattening. R. virginicus workers demonstrated substantial curve flattening when exposed to chlordane, methoxychlor, chlorpyrifos, deltamethrin, and fipronil. These findings indicate substantial intercolony and intra-colony differences in susceptibility to insecticides.     

Symbiosis of a termite and a sclerotium-forming fungus: Sclerotia mimic termite eggs

Brown balls, of a similar size but different shape to termite eggs, were found frequently in the piles of eggs of the subterranean termite Reticulitermes speratus. rDNA analysis identified the ball as the sclerotia of the fungus, Fibularhizoctonia sp. nov, which is phylogenetically closest to decay fungi, Athelia spp. Laboratory observation showed that the workers gathered the eggs and the sclerotia indiscriminately, even if they were widely scattered in a Petri dish, and piled them up in a specific place for egg care. We compared the morphology of the eggs with that of sclerotia of Fibularhizoctonia spp. and Athelia spp. in relation to egg carrying behaviour, and found that the workers could only carry the Fibularhizoctonia spp. sclerotia whose diameters were similar to the short diameter of the eggs. We also conducted a bioassay using termite eggs and dummy eggs (glass beads and sea sand) of two diameter-classes, coated with or without the egg-derived chemicals. The workers recognized the eggs based on a combination of the size, shape, and chemical cues. All the results suggested that the sclerotia mimic the eggs both morphologically and chemically. Finally, we found that the workers suppressed germination of sclerotia, and termite egg survival increased in the presence of sclerotia only if they were tended by the workers. If the workers were removed experimentally, the sclerotia germinated and grew by exploiting termite eggs. These results suggest that the sclerotia protect termite eggs from putative pathogens.