Does kin structure explain the occurrence of workers in a lower termite?

Kinship plays a fundamental role in the origin of social life. It is also predicted to affect numerous details within animal societies, yet recent studies revealed equivocal results. We tested the influence of relatedness for the occurrence of workers in the termite Cryptotermes secundus. Here individuals are developmentally flexible to remain workers or to become dispersing sexuals that found new colonies. Furthermore, colony relatedness naturally increases with inbreeding and decreases when neighboring colonies fuse. Similar to recent studies on social Hymenoptera, our experimental change in relatedness gave equivocal results. Reducing relatedness within colonies did not have an effect, but individuals in inbred colonies were less likely to disperse and more likely to remain workers as predicted by kinship arguments. Several explanations for the interpretation of these equivocal results are provided.     

Ectobiotic spirochetes of flagellates from the termite Mastotermes darwiniensis: attachment and cyst formation

The association of the gut flagellates Mixotricha paradoxa and Deltotrichonympha sp. from the termite Mastotermes darwiniensis with ectobiotic spirochetes and bacterial rods is investigated with light and electron microscopy. Treatment with different chemicals disturbing molecular interactions and use of the freeze-fracture and freeze-etch technique show that hydrophobic interactions and integral membrane proteins seem to be involved in the firm attachment at the contact sites. Application of antibiotics reduces the number of ectobionts and leads to a disintegration of the cortical attachment systems. As a result Mixotricha becomes spherical and immotile. In both flagellates the antibiotics have a further effect: they lead to a transformation of some of the spirochetes into cystic bodies. Cyst formation of ectobiotic spirochetes is here reported for the first time. Starvation has a similar but less dramatic influence than antibiotics. The cysts contain protoplasmic cylinders in the periphery and sometimes larger central bodies. Production of dormant cystic forms may be a survival mechanism under hostile conditions.     

地质变迁与云南白蚁的发生

由不同板块相嵌构成的云贵高原,是当今世界上形成比较新、海拔比较高的高原之一。高原中的地质历史,反映在二十多亿年来完整的地层中所包含的丰富的古生物化石种类。据统计,已发现的各类化石有14个门类、650多属、2,300多种。是我国古生物类群比较集中和在进化上较完整的地区,也是研究高原的形成和生物的起源和演化历史的珍贵材料。本文就云南在地质变迁过程中所产生的某些影响,试对云南白蚁的发生做初步探讨。     

白蚁的外部形态和分类系统

等翅目Isoptera(白蚁)在有翅昆虫亚纲进化的谱系中是属于一类比较原始的昆虫,与蜚蠊目Blattaria昆虫有比较密切的亲缘关系。 白蚁有翅成虫的头部形态、前后翅的等同、翅脉的复杂结构以及腹部的形态,都和低等的有翅昆虫或古代绝灭的昆虫相类似。但白蚁的生活习性和兵蚁的形态特征,在整个昆虫纲中是属于极为进化的一个类群。兵蚁的形态极为特化。双眼的退化、前后翅的     

Inconspicuous matured males of worker form are produced in orphaned colonies of Reticulitermes speratus (Isoptera: Rhinotermitidae) and participate in reproduction

Differentiation of neotenics is easily induced by orphaning the worker termites of Reticulitermes speratus (Kolbe). Although it has previously been reported that the sex ratio of neotenics is female-biased, the background of this phenomenon and the gonad developmental process of workers in artificially orphaned colonies are unknown. Although both male and female conspicuous neotenics can emerge as a response to the orphaning of the colony, we observed that majority of the reproductive males that are formed do not molt into the neotenic morph and are therefore inconspicuous in the population. Participation of the inconspicuous reproductive males in sexual reproduction was confirmed by genetic analysis. Slight pigmentation of the abdominal sternites is the only characteristic of the inconspicuous reproductive males that enables them to be distinguished from normal male workers. The presence of the female ergatoid (one type of female neotenic) did not induce the production of inconspicuous reproductive males during the 12-week experiment time.     

Termite resistance of solid wood and plywood treated with quaternary ammonia compounds and common fire retardants

The ability of termites to attack solid wood and plywood treated with quaternary ammonia compounds and common fire retardants was evaluated. The plywood and solid-wood specimens treated with either monoammonium phosphate (MAP), diammonium phosphate (DAP), ammonium sulfate (AS), didecyl dimethyl ammonium chloride (DDAC), or didecyl dimethyl ammonium tetrafluoroborate (DBF) were subjected to termite resistance tests using the subterranean termites Coptotermes formosanus Shiraki under laboratory conditions. The lowest mass losses and the highest termite mortalities were obtained for the solid-wood and plywood specimens treated with DDAC and DBF. Higher termite mortalities were seen in the plywood specimens treated with the fire retardants when compared to the solid-wood specimens. The MAP, DAP, and AS treatments lowered the mass losses in both solid-wood and plywood specimens in comparison with control specimens; however, DBF and DDAC protected specimens well against termite attack at both concentration levels tested.     

A new genus and species of mandibulate nasute termite (Isoptera, Termitidae, Syntermitinae) from Brazil

Acangaobitermes krishnaigen. et sp. n., is described here, based on soldiers and workers collected in Brazil. Some characteristics suggest a close kinship with Noirotitermes Cancello & Myles, and both genera share the following traits absent in all other Syntermitinae: the microsculpturing on the soldier head capsule surface with internal granulations; the piercing mandibles with a single very reduced marginal tooth and the worker very similar in both genera. The most conspicuous differences between Acangaobitermes and Noirotitermes are the shape of the soldier head, the frontal tube and pronotum. The shape of the soldier head in Noirotitermes is unusual, with a very broad and short frontal tube, four conspicuous protuberances like sharp corners at the rear, while in the new genus the posterior contour of the head is devoid of these protuberances. The frontal tube of Acangaobitermes is elongate and conical, while in Noirotitermes it is short and very broad. The pronotum of Acangaobitermes is saddle-shaped as is usual in other Syntermitinae, while it is aberrant in Noirotitermes.     

First record of the termite family Kalotermitidae (Blattodea: Termitoidae) in Korea

The drywood termite Kalotermitidae Froggatt, represented by Glyptotermes nakajimai Morimoto, is identified for the first time in Korea. They were collected in Yeoseo-do Island, the southern part of the Korean peninsula. A key to the termite species in Korea, habitus photographs of all castes, ecological information, and illustrations of diagnostic characters are provided.