白蚁取食行为多型及其机理

对白蚁取食行为的研究涉及5科18属38种白蚁。其取食行为多型可归纳为3类:(1)工蚁主导型:采食活动基本上由工蚁完成,兵蚁不参与或仅极少数个体参与,食物侦查或保护采食工蚁的职能不显著;(2)工蚁-兵蚁协同型:这是白蚁采食组织的常见类型,兵蚁成为采食队伍的固定成员,负责采食活动的安全侦查与防卫、食物源侦查等工作;(3)假工蚁主导型:由于尚未分化形成专职的工蚁,因而大龄幼蚁(广义的假工蚁)成为采食活动的主力,同时兼有巢内的保护职能。在食物加工和分配过程中,低等白蚁的幼蚁在未获得消化纤维素能力前主要通过肛交哺获得营养物质和共生物,且肛交哺是新蜕皮个体重新获得共生鞭毛虫的途径。高等白蚁幼龄工蚁负责食物加工、依赖型品级通过口交哺获得营养物质。白蚁采食活动中的行为多型受踪迹信息素控制,不同品级个体腹板腺有明显分化;不同品级和发育阶段个体食性分化与消化道结构、消化酶活性密切相关;保幼激素影响交哺行为以及消化酶基因表达。本文在评述研究进展的同时,对进一步研究提出了展望。     

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。     

尖唇散白蚁的梳理清洁行为和食物交哺行为

为了了解尖唇散白蚁梳理清洁行为和交哺行为,为防治该种白蚁提供依据,通过定性观察和定量测定的方法对尖唇散白蚁的梳理清洁行为和交哺行为进行了研究。结果表明:尖唇散白蚁的梳理清洁行为主要由4龄以上工蚁完成,4~6龄的若蚁也参与,但不及工蚁频繁;梳理清洁行为占到其昼夜活动时间的1.6%左右,当白蚁体表沾染污物时,如体表沾有染料或真菌孢子等,梳理清洁行为的频率增加,占用的时间也增多,人为用染料污染白蚁体表,梳理清洁行为可占到6.5%;尖唇散白蚁的交哺行为可发生于各个品级之间,其中工蚁是交哺行为中最活跃的品级,其他各品级均可接受来自工蚁的饲喂;6龄以上工蚁对工蚁的染料食物交哺测试显示,取食后24 h受喂工蚁获得的食物量仅占原取食工蚁取食量的5.86%,48 h饲喂者与受喂者消化道食物量大致持平,并随时间推移逐渐减少,受喂者消化道中的食物始终低于饲喂者。本研究结果支持散白蚁的交哺行为属于层叠式交哺模式的观点。     

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。     

黑翅土白蚁触角感器的扫描电镜观察

【目的】通过黑翅土白蚁Odontotermes fomosanus(Shiraki)幼蚁、工蚁、兵蚁触角感器种类、数量及分布的研究,分析不同龄幼蚁、工蚁和兵蚁的触角感器特征,为进一步研究触角感器发育特点及不同个体的行为分化机制提供参考。【方法】通过扫描电镜观察触角形态,分析触角节数、感器种类、数量及分布特征。【结果】工蚁、兵蚁、幼蚁个体触角长度差异显著,触角长度顺序:工蚁>兵蚁>3龄幼蚁>2龄幼蚁>1龄幼蚁;触角感器共有9种类型,分别为短毛形感器、长毛形感器、短刺形感器、长刺形感器、锥状B?hm氏鬃毛、球状钟形感器、刺突状钟形感器、球状钟形感器与刺突状钟形感器中间型、长刺具泡状感器。工蚁、兵蚁缺少长刺具泡状感器。幼蚁触角感器种类和数量随龄数而增加,1龄幼蚁具7种感器,缺少球状钟形感器和球状钟形感器与刺突状钟形感器中间型2种类型;2龄幼蚁具有8种感器,缺球状钟形感器;3龄幼蚁具有全部9种类型感器。【结论】黑翅土白蚁幼蚁、工蚁、兵蚁触角节数和感器显著差异,可作为幼蚁龄数以及非生殖品级判别的形态指标,应用于白蚁非生殖品级行为多型等相关研究。     

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。     

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。     

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。     

两种鼻白蚁之间的入侵关系

设计了5个实验以研究台湾乳白蚁(Coptotermes formosanus)和黄肢散白蚁(Reticulitermes flavipes)的种间斗争关系。所试白蚁来自阿拉巴马州。实验1将两组白蚁的兵蚁和工蚁以自然比例混合(台湾乳白蚁工蚁：兵蚁＝20：5,黄肢散白蚁工蚁：兵蚁＝24：1);实验2观察了双方同数量(各25头)工蚁的种间斗争能力;实验3观察两者同数量(各5头)兵蚁的种间斗争关系;实验4、5分别研究双方工蚁与兵蚁的斗争关系。因两种工蚁形态相似,所以在实验前用0．1％Nile blue A染过的滤纸饲喂一方白蚁24h使虫体着色以便观察。所有实验在22℃,65％RH荧光灯下进行。每个实验将两方白蚁同时放入一培养皿中,观察至一方100％受伤,然后把培养皿移到培养箱内,24小时后统计死亡率。结果表明,实验一开始,双方的工蚁和兵蚁都立即进入残酷的厮杀斗争,台湾乳白蚁兵蚁和工蚁的斗争能力都明显强于黄肢散白蚁;兵蚁的斗争行为不受工蚁的影响,工蚁的斗争能力也不受兵蚁的制约。实验中台湾乳白蚁的工蚁与黄肢散白蚁的兵蚁攻击能力相当,但黄肢散白蚁的工蚁却远弱于台湾乳白蚁的兵蚁。上述结果说明,自然界中不可能出现此两种白蚁群体的偶然性融合;外来的台湾乳白蚁很可能在其群体建立的地区占据优势[动物学报49(3)：295—302,2003]。     

Influence of caste polyethism on longevity of workers in social insect colonies

Different patterns of division of labor can affect the expected longevity of social insects workers. It has been earlier suggested that when tasks performed inside and outside colony are equally risky then the expected longevity of workers in colonies with caste polyethism is greater than that in colonies without polyethism. To verify these predictions I used a model assuming two sets of tasks, associated with different mortality rates. In the colony without polyethism the workers preformed safe and risky tasks in turn, while in the colony with caste polyethism the workers specialized in only one set of tasks. The outcomes suggest that the expected longevity of workers in colonies with caste polyethism cannot be greater than that in colonies without polyethism. Only if there is no aging and under some special and rare conditions are there no differences in expected longevity between colonies with and without caste polyethism. If aging is independent of activity, caste polyethism does not shorten longevity when all tasks in the colony are equally risky. The results can explain why caste polyethism is not as widespread among social insects as age polyethism.     

Worker Age, Ovary Development, and Temporal Polyethism in the Swarm-Founding Wasp Polybia occidentalis (Hymenoptera: Vespidae)

I measured oocyte sizes of Polybia occidentalis workers to assess whether ovary development corresponded with adult age or with individual variation in behavior. Workers exhibited temporal polyethism by first working inside the nest, then performing on-nest tasks, and later foraging and defending the nest. Individuals varied in their ages at first performance of each of these sets of behavioral acts. Ovary development corresponded strongly with adult age. Workers' ovaries declined quickly after an initial phase of partial development. The period of ovary decline overlapped with the age range at which most workers began performing tasks on the exterior nest surface. However, after accounting for age effects, individual behavioral differences (rate of temporal polyethism and performance of foraging and defense tasks) did not correspond with ovary development. These data suggest that ovary development had little or no effect on variation in task performance by P. occidentalis workers on the nest surface.     

Nutritional function of replete workers in the pharaoh's ant, Monomorium pharaonis (L.)

Summary: Queens of the pharaoh's ant Monomorium pharaonis (L.), like several other ant species, feed on larval secretions as their main nourishment and their fecundity is positively correlated with the number of large larvae present in the nest. The surplus of secretions produced by larvae is stored in a temporary caste of replete workers, which comprises young workers who remain in the nest and store liquid nourishment. Repletes are characterised by a conspicuously large gaster, caused by large amounts of liquid food stored in the crop, from which it may be regurgitated and distributed among colony members. In this study, repletes of pharaoh's ants were demonstrated to be functioning as buffers, smoothing fluctuations in availability of high quality food to the reproductive queens when larvae are scarce or missing, thus temporarily keeping up the egg production of queens.¶In undisturbed two-queen colonies with 20 large worker larvae and 30 workers (15 young and 15 old workers), approximately 10 repletes developed (one replete per two larvae). Development of older workers into repletes, when some or all repletes had been removed from the colonies, demonstrated that their temporal polyethism exhibits great plasticity in this trait.¶This study confirmed that, in pharaoh's ants, the regulation of fecundity depends not only on the food flow to the queen from larvae or from repletes but also on an unknown larval stimulus.¶The term crop repletes is suggested for replete workers which use their crop to store nourishment, as opposed to fat-body repletes, which store nourishment in their fat body.¶The presence of brood tending crop repletes in nests in several European ant species of Leptothorax, Myrmica, and Lasius, show that repletism is a common trait in ants, and that it may play an important role in regulation of nutrition in ant colonies, as demonstrated in Monomorium pharaonis.     

Functional flexibility of the honey bee hypopharyngeal gland in a dequeened colony

The role of the worker honey bee Apis mellifera L. changes depending on age after eclosion (age polyethism): young workers (nurse bees) take care of their brood by synthesizing and secreting brood food (royal jelly), while older workers (foragers) forage for nectar and process it into honey. Previously, we showed that the major proteins synthesized in the hypopharyngeal gland of the worker change from brood food proteins to alpha-glucosidase at the single secretory cell level in parallel with this age polyethism [Kubo et al., J. Biochem. 119, 291-295 (1996); Ohashi et al., Eur. J. Biochem. 249, 797-802 (1997)]. Here, we examined whether the function of the hypopharyngeal gland has flexibility depending on the colony conditions, by creating a dequeened colony in which the older workers were compelled to feed the drone larvae. It was found that most of the older workers in the dequeened colony synthesized brood food proteins as did nurse bees. Furthermore, the percentage of workers that synthesized brood food proteins was maintained at 80-90% of the total workers for at least two months, as in a normal colony. These results indicate that the function of the hypopharyngeal gland cells of the worker has flexibility and can, if necessary, be maintained as that of the nurse bee, depending on the condition of the colony.     

Biochemical characterization of digestive enzymes in the black soldier fly,Hermetia illucens (Diptera: Stratiomyidae)

The black soldier fly, Hermetia illucens, is beneficial because its larvae feed on organic materials derived from plants, animals and humans and promote the recycling of food waste and organic materials. We investigated the biochemical properties of digestive enzymes released from the salivary gland and gut of the black soldier fly. Because the gut extracts of the black soldier fly larvae had high amylase, lipase and protease activities, we suggested that the black soldier fly might belong to the polyphagous insect group. In addition, a strong trypsin-like protease activity was observed in the gut extracts of the black soldier fly larvae. Higher activities of leucine arylamidase, α-galactosidase, β-galactosidase, α-mannosidase and α-fucosidase were observed from the gut extracts of the black soldier fly larvae compared with those of house fly larvae. These findings may explain previous reports that the black soldier fly larvae can digest food wastes and organic materials more efficiently than any other known species of fly.     

Methoprene accelerates age polyethism in workers of a social wasp (Polybia occidentalis)

Abstract. Topical applications of the Juvenile Hormone (JH) analogue methoprene to 1-day-old adult workers of the highly eusocial wasp Polybia occidentalis (Olivier) (Hymenoptera: Vespidae) accelerate the rate of age polyethism. Longevity of laboratory-reared wasps is negatively correlated with dose of topically applied methoprene. Doses of 25 μg methoprene or greater are lethal. Untreated wasps show marked age polyethism in the field. Age of first performance of acts in seven behavioural categories (in-nest, transition to outside, non-task on nest envelope, nest maintenance, foraged material handling, defence, and foraging) is negatively correlated with methoprene dose. Topical applications of methoprene accelerate age polyethism of highly eusocial bee and wasp workers, but do not have this effect on primitively eusocial bees and wasps, suggesting that JH control of age polyethism evolved independently in advanced species of Apidae and Vespidae.     

The importance of daylength and queens for larval care by young workers of the ant Myrmica rubra L.

ABSTRACT. Workers whilst still less than a month from emergence rear early stage larvae better in a 16h day than in one of 14h. The callows must perceive the diel rhythm directly because there are no foragers to give them a clue, and the larvae are kept in the dark and cannot respond directly. This, and the study of egg-laying by young workers that preceded it, indicates that the extra hours daylight enable the workers to avoid the reproductive diapause that normally prepares them for hibernation. They retain active ovaries, ingest and share food with larvae either as trophic eggs or as a regurgitate from the crop.
In late summer, callows can rear sexual larvae in spring condition. Queens have a small negative effect on this, expressed as a smaller, though still gyne, pupa produced a little earlier. This weak response to queens develops into a strong negative one at a constant temperature of either 10 or 20°C. The workers then behave as they normally do in spring, and feed a watery regurgitate (dietary control) or, if this fails to arrest sexual development, physically harass the larvae by biting them in the ventral thorax (manipulative control). Large workers then result instead of gynes.     

Structure of the gut contents of Trichogramma australicum Girault (Hymenoptera: Trichogrammatidae) larvae fixed in situ in eggs of its host Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

Abstract Trichogramma australicum larvae develop most rapidly in younger eggs of its host, the pest lepidopteran Helicoverpa armigera . To establish how the developmental stage of the host affects the diet of T. australicum , larvae were fixed in situ in eggs of H. armigera of different ages and the structure of the egg contents and parasitoid gut contents examined histologically. Larvae feeding on newly laid host eggs contain primarily yolk particles in their gut, while larvae feeding on older hosts contain necrotic cells and yolk particles. The gut of T. australicum larvae does not contain organised tissue remnants, indicating that larvae feed primarily by sucking food into their pharynx and feed best on a mixture of particulate semisolids in a liquid matrix. Secretory structures of T. australicum larvae that could be involved in modifying the host environment were examined. The hindgut is modified to form an anal vesicle with a number of attributes suggesting that it may be a specialised secretory structure. The paired salivary glands open to the exterior via a common duct.     

Age polyethism,idiosyncrasy and behavioural flexibility in the queenless ponerine ant,Diacamma sp.

Age-related behavioural change of individually marked and known-age workers of a colony ofDiacamma sp. was observed through entire ant lives in the laboratory for more than a year. Although typical age polyethism was observed, activity of inside and outside tasks, life span, or time schedule of behavioural change varied considerably among workers. Idiosyncrasies in age-related behavioural change was detected among workers that eclosed on the same day. Cluster analyses revealed that individual patterns of behavioural change tended to be different when eclosion dates were far apart. This suggests that most workers change their behaviour flexibly. Thus, there is little effect of idiosyncrasy on colony response to changes in colony condition.     

Age polyethism in the leaf-cutting ant Acromyrmex subterraneus brunneus Forel, 1911 (Hym., Formicidae)

Abstract  This study describes and quantifies the behavioural acts of two laboratory colonies of Acromyrmex subterraneus brunneus by investigating worker age polyethism. Twenty-nine behavioural acts were recorded during the 19-week observation period. Young individuals performed tasks inside the nest related to brood care and care for the fungus garden, whereas older individuals performed activities outside the nest such as foraging and activities in the waste chamber. The average longevity (±SD) was 108.21 ± 3.30, 109.15 ± 1.92 and 122.71 ± 1.55 days for large, medium and small workers, respectively. The small-sized workers presented a higher probability of reaching older age than large- and medium-sized workers. This study describes task switching according to age polyethism and the relationship of physical and temporal subcastes.