Proximate factors influencing soldier development in the basal termite <Emphasis Type="Italic">Cryptotermes secundus</Emphasis> (Hill)

Summary Regulation of soldier development in termites at the endocrinological and social scale was intensively studied in the 60s and 70s, but conclusive results are still scanty. In termites, the presence of soldiers inhibits further soldier differentiation, but the mechanism is not well understood. Secretions from the frontal glands seem to be important, but dry- and dampwood termites do not have frontal glands. We investigated the influence of precocene I, a JH-antagonist, and of soldier head extracts on the development of soldiers in the drywood termite, Cryptotermes secundus (Hill). Soldierless colonies produced fewer soldiers when treated with precocene I or soldier head extract than control colonies. Furthermore, colonies treated with precocene I had produced worker-nymph intercastes, last stage nymphs and alates by the end of the experiment (after six months) which were not present in control colonies. Hence, both treatments inhibited soldier development while precocene I simultaneously promoted the development of adult traits, probably by reducing (directly or indirectly) the JH level. The inhibition effect of the soldier head extract indicates that at least in termites without a frontal gland, other sources of material in the head have a regulatory function.     

Paraconvexitermes acangapua (Isoptera: Termitidae,Nasutitermitinae), a new genus and new species of the so-called “small Neotropical soil-feeding nasutes” from South America

A new genus Paraconvexitermes is described, comprising Paraconvexitermes acangapua, new species, P. nigricornis (Holmgren) and P. junceus (Emerson), both previously in Convexitermes Holmgren. Now, Convexitermes comprises C. manni Emerson and C. convexifrons (Holmgren). The worker’s digestive tube of both genera along with those of Atlantitermes species allowed to get a better definition of these three genera. Illustrations on the digestive tube and mandibles of workers, soldier’s head, alate’s head and secondary reproductive female of the new genus and species are provided. The phylogenetic relationships with the other nasute genera are discussed along with the “soil feeding” concept.     

Chinese species of genus Notopygus Holmgren (Hymenoptera,Ichneumonidae, Ctenopelmatinae) with description of a new species

A new species, Notopygus longiventris Sun & Sheng, sp. n., collected from Benxi County, Liaoning Province, China, and N. emarginatus Holmgren, 1857, reared from Neurotoma sibirica Gussakovskij (Hymenoptera, Pamphiliidae) from Haicheng, Liaoning Province, are reported. The new species is placed within existing key to species.     

截头堆砂白蚁研究概况

截头堆砂白蚁Cryptotermes domestictis是世界性蛀木害虫, 也是我国主要危害木材的白蚁之一。本文重点综述了我国截头堆砂白蚁补充型繁殖蚁的形成、生存、繁殖和扩散, 以及成熟群体的分飞, 原始繁殖蚁的形成周期和行为特点, 初建群体的形成、发展发育和取食行为的生物学和生态学研究进展。并且对该种白蚁的控制进行了探讨, 为控制该种白蚁的扩散、传播和为害提供理论依据。     

Isolation and characterization of six microsatellite loci in the drywood termite Cryptotermes secundus (Kalotermitidae)

The Kalotermitidae is a family of lower termites and its species are ideal to study the evolution and maintenance of eusociality within the Isoptera. Co‐dominant genetic markers are an essential tool to elucidate the putatively complex colony and population structure. Six polymorphic microsatellite loci were identified in the drywood termite Cryptotermes secundus (Kalotermitidae). To test the variability of the markers, 18 colonies (n = 18) from Darwin (Australia) were assayed. We found two to eight alleles per locus with the level of observed heterozygosity at each locus ranging from 0.00 to 0.53. The significantly positive F_IT value suggests that some kind of inbreeding does occur in this population.     

Interspecific competition between Diadegma semiclausum Hellen and Diadegma mollipla (Holmgren), parasitoids of the diamondback moth, Plutella xylostella (L), feeding on a new host plant

Interspecific competition between an introduced parasitoid species aimed at controlling a herbivorous pest species and a native parasitoid parasitising the same host may influence the success of classical biological control programmes. In Kenya, interspecific competition between an introduced and a local parasitoid on two diamondback moth populations (DBM, Plutella xylostella) was investigated on two different host plants. We tested simultaneous and delayed competition of the local parasitoid Diadegma mollipla Holmgren and its exotic congenus D. semiclausum Hellen on a newly aquired DBM host plant (snowpea) in the laboratory. Under simultaneous competition, D. mollipla produced more progeny than D. semiclausum on snowpea. A head start of D. Mollipla, of four and eight hours before its congenus was introduced, resulted in a similar number of progeny of both species. In delayed competition (time intervals of 24 h, 48 h and 72 h), progeny production was similar for both parasitoids when the time interval was 24 h, irrespective of which species parasitized first. More progeny was produced by the species which attacked first, when the time interval was greater than 24 h, although it was only significant at 72 h. Competitive abilites of both parasitoids on the new host plant differed largely between laboratory and semi-field conditions. The influence of two host plants (snowpea and cabbage) on competition was studied in the greenhouse with different host and parasitoid densities. Parasitism levels of D. semiclausum were significantly higher than those of D. mollipla, regardless of host plant, host and parasitoid densities, but progeny production of D. mollipla on snowpea was still slightly higher than on cabbage. As compared to the confinement of parasitoids and larvae to small containers, D. mollipla parasitized very few larvae in the cages. Competitive ability of the two parasitoid species tested was influenced both by the density of the searching females and by parameters related to either the host plant and/or the herbivorous hosts.     

First records of urban invasive Cryptotermes brevis (Isoptera: Kalotermitidae) in continental Spain and Portugal

Occurrence of the West Indian drywood termite, Cryptotermes brevis, is registered for the first time as established populations in Barcelona (Spain) and also additional information is given regarding a recent record from Lisbon (Portugal). This serious invasive termite pest was detected in five buildings in Barcelona, Spain and one building in Lisbon, Portugal.     

四川象尉属二新种（等翅目：尉科）

最近,作者在整理四川省象尉亚科Nasutitermitinae标本时,发现象尉属Nasutitermes Dudley二新种,现记述如下。     

Molting dynamics and juvenile hormone titer profiles in the nymphal stages of a lower termite, Cryptotermes secundus (Kalotermitidae)--signatures of developmental plasticity

Termites are social cockroaches and this sociality is founded on a high plasticity during development. Three molting types (progressive, stationary and regressive molts) are fundamental to achieve plasticity during alate/sexual development, and they make termites a major challenge to any model on endocrine regulation in insect development. As the endocrine signatures underpinning this plasticity are barely understood, we studied the developmental dynamics and their underlying juvenile hormone (JH) titers in a wood-dwelling termite, Cryptotermes secundus, which is characterized by an ancestral life style of living in dead wood and individuals being totipotent in development. The following general pattern elements could be identified during winged sexual development (i) regressive molts were accompanied by longer intermolt periods than other molting types, (ii) JH titers decreased gradually during the developmental transition from larva (immatures without wing buds), to nymph (immatures with wing buds), to winged adult, (iii) in all nymphal stages, the JH titer rose before the next molt and dropped thereafter within the first week, (iv) considerable variation in JH titers occurred in the midphase of the molting cycle of the 2nd and 3rd nymphal instar, inferring that this variation may reflect the underlying endocrine signature of each of the three molting types, (v) the 4th nymphal instar, the shortest of all, seems to be a switch point in development, as nymphs in this stage mainly developed progressively. When comparing these patterns with endocrine signatures seen in cockroaches, the developmental program of Cryptotermes can be interpreted as a co-option and repetitive use of hormonal dynamics of the post dorsal-closure phase of cockroach embryonic development.     

Comparison of the behavioural and physiological responses to humidity of five species of dry-wood termites, Cryptotermes species

ABSTRACT. A circular humidity gradient apparatus with a porous cellulose substrate was used to compare the humidity responses of pseudoworkers (immature wood-feeding forms) of five species of dry-wood termites. Four of these species are widely distributed pests of buildings: Cryptotermes brevis (Walker), C. cynocephalus Light, C. dudleyi Banks and C. havilandi (Sjöstedt). The fifth species, C. naudei Coaton, has not been recorded from buildings. C. havilandi, C. cynocephalus and C. naudei were found to tend to group and feed at humidites above 90% r.h., while C. dudleyi pseudoworkers avoided humidities above 90% r.h. and below 70% r.h. These results accord with the results of studies on the effects of relative humidity on feeding and reproduction of these species. The behaviour of the most widespread species, C. brevis , seems to be closely associated with its ability to undergo acclimatization and to feed efficiently at either medium ( c. 60%) or high ( c. 90%) relative humidity. C. brevis kept at 89% r.h. showed an increased tendency to group at humidities above 90%, with a lower temperature preference, changes in faecal pellet formation and, for one population at least, an increased tolerance of exposure to saturated air. The humidity preferences at constant temperature were compared with the temperature preferences of the same individuals examined in uniform humidity. The value of behavioural responses as indicators of physiological differences between species and populations is considered.     

The ontogeny of soldiers in Prorhinotermes simplex (Isoptera, Rhinotermitidae)

The ontogeny of the soldier caste in Prorhinotermes simplex is studied with emphasis on the instar origin of soldiers, the duration of the presoldier stage, and changes in external anatomy during the soldier morphogenesis. The soldiers of different instar origin are compared morphometrically and by analysis of the soldier defensive secretion. The soldiers were found to develop from larvae of the second up to the eighth instar, via a short (13–17 days) presoldier stage. The early soldier instars were found exclusively in incipient colonies while the mature colony contains late instar soldiers only. The abrupt change in the external anatomy occurs in two steps. During the larva-presoldier moult, the head increases in length but only slightly in width. During the presoldier-soldier moult, both the length and width of the head increase markedly and the typical cordate shape is attained; the relative size of the pronotum increases considerably. The long falcate mandibles develop mainly during the larva-presoldier moult. One antennal segment is added during these two moults. With increasing instar age of soldiers a relative increase of the pronotum and the head size in its posterior region was observed. No functional differences in external anatomy were found among the six soldier instars. The composition of the frontal gland secretion is similar in the six soldier instars, an extraordinarily high amount of a defensive substance, (E)-1-nitropentadecene, was detected together with (Z,E)-α-farnesene, presumably an alarm substance. The strategy of soldier production is discussed. We conclude that the observed patterns of soldier production in P. simplex correspond well to its ecological strategy of an advanced single-site nester able to migrate and form foraging groups. Received 16 August 2005; revised 21 November and 6 February 2006; accepted 16 February 2006.     

Cyclic CO(2) release in Cryptotermes cavifrons Banks, Incisitermes tabogae (Snyder) and I. minor (Hagen) (Isoptera: Kalotermitidae).

CO(2) release patterns of three drywood termite species were investigated using flow-through respirometry techniques. Eight hours of real-time CO(2) release data were recorded for pseudergates of Cryptotermes cavifrons Banks, Incisitermes minor (Hagen), and I. tabogae (Snyder) at 20-40 degrees C. Cyclic release of CO(2) was observed in 20-90% of C. cavifrons, 70-100% of I. tabogae, and 87-100% of I. minor pseudergates. Variability of the recordings (calculated as the coefficient of variability or CV) was used to estimate the level of cycling in each recording. CV ranged from 14.53+/-2.57 (40 degrees C) to 32.33+/-1.12% (30 degrees C) in C. cavifrons, 20.24+/-2.44 (35 degrees C) to 67.3+/-10.3% (20 degrees C) in I. minor, and 15.9+/-1.46 (35 degrees C) to 34.15+/-6.18% (20 degrees C) in I. tabogae. The relationship between temperature and CV for each species was modeled using non-linear regression. CV of both Incisitermes spp. decreased exponentially with temperature, while C. cavifrons CV followed a Gaussian model, indicating an optimal cycling temperature of approximately 30 degrees C. Mean V.CO(2) values were determined for each species as a function of temperature, and ranged from 0.1 ml CO(2) g(-1) h(-1) (I. minor at 20 degrees C) to 0.8 ml CO(2) g(-1) h(-1) (C. cavifrons at 40 degrees C). For all three species, V.CO(2) significantly increased linearly with temperature. Colinearity tests indicated that different models described the V.CO(2) relationship with temperature for both genera. Q(10) values for V.CO(2) over the range of 20-40 degrees C were 1.92 for I. minor, 1.66 for I. tabogae, and 1.62 for C. cavifrons pseudergates.     

First record of intersex in neotenic reproductives of the termite Cryptotermes brevis (Isoptera: Kalotermitidae)

Drywood termites of the family Kalotermitidae present a very flexible developmental pattern, in which pseudergates are totipotent and may become reproductives. In this study, three colonies of Cryptotermes brevis headed by neotenic reproductives were used: (i) colony A, with a primary king and a neotenic queen; (ii) colony B, with a primary queen and a neotenic king; and (iii) colony C, with neotenic king and queen. The primary king from colony A and the neotenic king from colony B presented well‐developed reproductive systems, with conspicuous testicular lobes and cysts containing spermatozoa also observed in the seminal vesicles. The neotenic queen of colony A and the primary queen of colony B had ovaries with several oocytes in early developmental stages with some of them already vitellogenic and terminal, which suggests egg‐laying activity. Both of these queens presented the spermathecae lumen filled with spermatozoa. The queen of colony C had vitellogenic oocytes; however, the oocytes were not terminal and the lumen of spermathecae was devoid of spermatozoa and secretions. The seminal vesicles of colony C neotenic king have no spermatozoa. This king displayed a previtellogenic oocyte among its testicular lobes, which suggested that this individual was an intersex.     

Identification of the Diadegma species (Hymenoptera: Ichneumonidae, Campopleginae) attacking the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae)

The species of Diadegma that attack Plutella xylostella (Linnaeus) are revised. Following a morphometric study involving principal components and discriminant analyses, seven distinct morphospecies are recognized. One species is described as new: D. novaezealandiae from New Zealand. Diadegma mollipla (Holmgren) is the name for the species from sub-Saharan Africa and some Indian Ocean and South Atlantic islands. Diadegma varuna Gupta syn. nov. and D. niponica Kusigemati syn. nov. are both synonymized with D. fenestrale (Holmgren). Diadegma xylostellae Kusigemati is strongly presumed to be a synonym of D. semiclausum (Hellén). An illustrated identification key is provided and each species is described in a standard way.     

四川新白蚁属一新种记述(等翅目,木白蚁科)

记述新白蚁属1新种,屏山新白蚁 Neotermes Pingshanensis sp．nov．,新种与长颚新白蚁 Neotermes dolichognathus Xu et Han相近,但体色不同,头长/宽比例不同,触角第2节明显长于第3节,左上颚缘齿4枚,前胸背板前缘具深凹.危害物为潮湿木窗框.模式标本保存于成都市白蚁防治研究所.     

Endocrine signatures underlying plasticity in postembryonic development of a lower termite, Cryptotermes secundus (Kalotermitidae)

SUMMARY Wood-dwelling termites are characterized by an extremely high and unique developmental flexibility that allows workers, which are immatures, to explore all caste options. The endocrine signatures underlying this flexibility are only vaguely understood. We determined juvenile hormone (JH) and ecdysteroid hemolymph titers during postembryonic development and in terminal instars of the drywood termite Cryptotermes secundus using field and laboratory colonies. Postembryonic development is characterized by a drop in JH titers at the transition from larval (individuals without wing buds) to nymphal (individuals with wing buds) instars. JH titers were low in winged sexuals and reproducing primary reproductives (<200 pg/μl) but were by an order of magnitude higher in neotenic replacement reproductives. The unique regressive molts of termites seem to be characterized by elevated JH titers, compared with progressive or stationary molts. Ecdysteroid titers were generally low in nymphal instars and in primary reproductives (<50 pg/μl). It was only during the third and fourth nymphal instars and in winged sexuals where some individuals showed elevated ecdysteroid titers. These results are the most comprehensive endocrinological data set available for any lower termite, with the potential to serve as baseline for understanding the extreme developmental flexibility underlying the evolution of social life in termites.     

Phylogenetic analysis and trait evolution in Australian lineages of drywood termites (Isoptera, Kalotermitidae)

A phylogenetic analysis of Australian drywood termites (Isoptera, Kalotermitidae) based on partial sequence from the cytochrome oxidase II (COII) and cytochrome b genes is presented. In addition to providing new information on the evolutionary relationships among 25 species from seven genera, we evaluate the relative likelihoods of alternative topological hypotheses, including those derived from morphology-based classifications. We also test the applicability of a molecular clock for estimating the age of the Kalotermitidae and infer the evolution of species-specific variation for habitat type and soldier caste phragmosis by mapping this information onto the independently derived phylogeny. Maximum-likelihood analysis of both nucleotide and protein sequences from a multigene data set jointly support a single topology, which is shown to be the best estimate of the true phylogeny among the alternatives tested. Our results support the monophyly of all genera but question the discrimination between Procryptotermes and Cryptotermes. A basal dichotomy among generic groups suggests two principle lines of divergence within the family. Intergeneric relationships show mixed congruence to previous proposals, resulting in one morphology-based classification being rejected. A molecular clock hypothesis is not supported due to significant among-lineage rate heterogeneity in the COII gene. Patterns revealed through trait mapping suggest that the most recently diverged taxa tend to occupy the driest habitats and that these same taxa reflect a defensive transition away from large mandibulate soldiers toward small phragmotic soldiers. The association between habitat and defensibility supports the hypothesis that these two characters have been tightly linked throughout the social diversification of termites.     

New data on Nasutitermes from French Guiana (Isoptera: Termitidae: Nasutitermitinae)

Nasutitermes octopilis, N. ephratae, N. similis, N. guayanae, N. guayanae form columbicus, and N. surinamensis are cited for the first time from French Guiana on the basis of the soldier and worker castes. The mandible of major worker of N. surinamensis, of small soldier of N. costalis, small worker of N. ephratae, small and major worker of N. similis, and of the major worker of N. guayanae [“form” columbicus (Holmgren, 1910)] are described for the first time.