The toxicity of tributyltin oxide to the wood-boring beetles Lyctus brunneus Steph. and Anobium punctatum (Deg.)

When tributyltin oxide (TBTO) was tested by British Standard 3653 against Lyctus brunneus, 0·5 % solution, equivalent to 0·72 g/m₂ surface application, gave almost complete protection. Tests to BS 3651, using larvae of Anobium punctatum transferred into fully impregnated wood gave toxic limits of 1·39–2·93 kg/m³ TBTO when benzene was used as diluent. The use of white spirit as diluent gave lower toxic limits, probably due to combined toxic action of TBTO and white spirit residues. TBTO appears to have no contact action against the insects tested. Probit analysis of the test with A. punctatum gave an LD 50 of 0·254 kg/m³ and an LD99 of 3 kg/m³. The advantage of treating results by probit analysis rather than by deriving ‘toxic limits’ is discussed.     

Molecular Identity of Holomastigotes (Spirotrichonymphea,Parabasalia) with Descriptions of Holomastigotes flavipes n. sp. and Holomastigotes tibialis n. sp.

Holomastigotes is a protist genus (Parabasalia: Spirotrichonymphea) that resides in the hindguts of “lower” termites. It can be distinguished from other parabasalids by spiral flagellar bands that run along the entire length of the cell, an anterior nucleus, a reduced or absent axostyle, the presence of spherical vesicles inside the cells, and the absence of ingested wood particles. Eight species have been described based on their morphology so far, although no molecular data were available prior to this study. We determined the 18S rRNA gene sequences of Holomastigotes from the hindguts of Hodotermopsis sjostedti, Reticulitermes flavipes, Reticulitermes lucifugus, and Reticulitermes tibialis. Phylogenetic analyses placed all sequences in an exclusive and well‐supported clade with the type species, Holomastigotes elongatum from R. lucifugus. However, the phylogenetic position of Holomastigotes within the Spirotrichonymphea was not resolved. We describe two new species, Holomastigotes flavipes n. sp. and Holomastigotes tibialis n. sp., inhabiting the hindguts of R. flavipes and R. tibialis, respectively.     

Effect of ozone on respiration of adult Sitophilus oryzae (L.), Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.)

The effect of ozone on the respiration of three species of adult stored-product Coleoptera was tested in an air-tight flask. Sitophilus oryzae (L.), Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst) adults were exposed to atmosphere containing 0.1, 0.2 or 0.4 μg/ml initial ozone at 23–25 °C and 50% r.h. Carbon dioxide (CO₂) production reflected the respiration rates of insects and was determined with a gas chromatograph (GC). The experiments showed that the effects of ozone on respiration had two distinct phases. Phase 1 involved a lower respiration rate of the adult stored-product Coleoptera under ozone atmosphere and reflected the need for insects to reduce ozone toxicity. After 1 h, CO₂ production of S. oryzae was 3.19, 2.63, 2.27 and 1.99 μl/mg for the ozone concentration of 0, 0.1, 0.2 and 0.4 μg/ml, respectively. The results also showed that there were decreases in the rate of respiration in R. dominica and T. castaneum with an increase in ozone concentration. During phase 2, respiration of S. oryzae, R. dominica, and T. castaneum adults treated with ozone increased as the ozone degraded to oxygen. After 7 h, the effect of ozone on CO₂ production, relative to the control, changed from a decrease to an increase. The findings in relation to control strategies were discussed.     

Testing the effects of liquid eradicants on emergence of Anobium punctatum (Deg.)

A laboratory method is described for evaluating the effectiveness of insecticides in preventing the emergence of furniture beetles (Anobium punctatum (Deg.)). Composite blocks of Scots pine were prepared consisting of an untreated core containing larvae and two treated outer veneers from which all solvent had evaporated and through which beetles had to emerge. Dieldrin and gamma-BHC prevented emergence of beetles, dieldrin being the more effective material. The following did not prevent emergence at the concentrations tested: pentachlorophenol, zinc naphthenate, polychlor-naphthalene, copper-chrome-arsenate, tri-butyltin oxide.     

A bioenergetic study of a benthic nematode,Plectus palustris de man 1880, throughout its life cycle

Summary Respiration rates of the bacterivorous freshwater nematode Plectus palustris were measured during the whole life cycle of the species and for animals grown at two food densities. Covariance analysis showed that small, but significant differences exist in the elevation of the respiration rate—body weight regressions (R=aW ^b, in nl O₂/ind·h and g wet weight) for different food densities. At a food density of 6–9·10⁸ bacterial cells/ml the level of respiration is 14% lower compared to rates of animals cultured at a ten times higher food density. However, the allometric function, R-aW ^b, adequately describes the relationship of respiration and body weight only during the larval growth phase and for young females, while respiration rates of newly hatched larvae and mature females at maximal egg production have lower metabolic rates. Cumulated metabolic costs to attain a certain age, size and stage of development have been determined and are used in a subsequent paper (Schiemer et al., 1979) to calculate the energy budgets of the species.     

Sull' apparato genitale maschile diReticulitermes

Riassunto Si è studiata la struttura dell'apparato genitale maschile negli alati di 5 specie diReticulitermes: lucifugus, flavipes, hageni, tibialis, hesperus.Inlucifugus si è anche considerato il grado di funzionalità dell'apparato genitale in caste diverse.

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Summary Male genital apparatus morphology and functional activity have been studied in winged specimens ofReticulitermes: lucifugus Rossi,flavipes Kollar,hageni Banks,tibialis Banks,hesperus Banks; forlucifugus also specimens of other castes and stages have been considered.

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Résumé La morphologie et la fonction de l'appareil génital masculin ont été étudiées sur des exemplaires ailés deReticulitermes: lucifugus Rossi,flavipes Kollar,hageni Banks,tibialis Banks,hesperus Banks; pourlucifugus, on a considéré aussi des exemplaires d'autres castes stades.

     

Upper lethal temperature limits of the common furniture beetle Anobium punctatum (Coleoptera: Anobiidae)

The susceptibility of the egg, larval and adult stages of Anobium punctatum De Geer (Coleoptera: Anobiidae) to heat (46–54°C, 25–30% RH) was investigated. The larval stage was found to be most tolerant to heat. Very short exposure (5 min) of the larvae to temperatures of 52°C and above led to 100% mortality of the larvae. Treatment for 1.5 and 1 h at 47° and 48°C, respectively, led to 100% mortality. At 46°C, longer treatment time (2.5 h) was necessary. Exposure to 45°C for 3.5 h did not lead to immediate death of the larvae. The actual mortality is assumed to be greater than the results actually reported, as most of the larvae had not resumed normal activity at the end of the two-week observation period. The egg and adult stages were more sensitive to heat than the larvae; shorter exposure times were sufficient to obtain 100% mortality.     

Hydrogen emission by three wood-feeding subterranean termite species (Isoptera: Rhinotermitidae): Production and characteristics

Abstract Hydrogen emission by wood-feeding termites, Coptotermes formosanus, Reticulitermes flavipes and Reticulitermes virginicus, was investigated upon a cellulosic substrate as their food source. The emission rates among the three species tested were significantly different and R. virginicus demonstrated the greatest H₂ emission at 4.78 ± 0.15 μmol/h/g body weight. In a sealed test apparatus, H₂ emission for each termite species showed a quick increase at the initial incubation hours (3–6 h), followed by a slower growth, possibly due to the feedback inhibition by gas accumulation. Further investigation revealed that continuous H₂ emission could be maintained by reducing the H₂ partial pressure in the sealed container. The bioconversion of cellulose to molecular H₂ by the subterranean termites tested could reach as high as 3 858 ± 294 μmol/g cellulose, suggesting that the termite gut system is unique and efficient in H₂ conversion from cellulosic substrate.     

A new biological method to control Anobium punctatum,by using the parasitoid wasp Spathius exarator

Biological pest control by means of beneficial organisms is for long part of agriculture and Integrated Pest Management (IPM). A new and efficient strategy to control the most common timber pest species in churches and museums, the furniture beetle Anobium punctatum (De Geer) (Coleoptera: Anobiidae), is based on the parasitoid wasp species Spathius exarator (Linnaeus) (Hymenoptera: Braconidae). Once this braconid wasp detects its host species beneath the surface, it pierces the wood with its ovipositor to lay one single egg onto the beetle larva. After hatching, the wasp larva feeds on the beetle larva thereby killing it. Afterwards, it pupates and emerges through a self-gnawed hole as an adult wasp. The tiny, 0.5-mm-wide exit hole can easily be distinguished from the 1- to 2-mm-wide exit hole of A. punctatum. Laboratory tests revealed that female wasps have an average life span of 85 days and produce a total of 24 offspring, when nutrition is provided. Between 2012 and 2019, braconid wasps were introduced into 54 different A. punctatum infested buildings. Treatment success was monitored by examining exit holes of new beetles and wasps thereby calculating corresponding parasitism rates. After the first year of treatment, parasitism rates were significantly higher with a mean value of 0.15 when compared to untreated objects with a natural parasitism and a mean value of 0.08 (n = 54). Following treatment of three objects over a period of eight years, parasitism rates continuously increased from 0.02 up to 0.31. In a church organ, which was treated during this period, the monitoring revealed a complete suppression of pest activity. These data prove that this biological method of pest control is an efficient, sustainable and non-toxic option to manage the common furniture beetle.     

Sugli organi genitali maschili delle Rhinotermitidæ (isoptera)

Riassunto Si è studiato l'apparato genitale maschile di alcune caste e stadi diReticulitermes lucifugus e degli alati diPsammotermes assuanensis, Coptotermes sj?stedti, Schedorhinotermes javanicus, prestando particolare attenzione alla forma delle vescicole seminali, al loro contenuto, e all'attività del testicolo.

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Summary It has been studied the male genital apparate of some casts and stages ofReticulitermes lucifugus and of winged reproductives ofPsammotermes assuanensis, Coptotermes sj?stedti, Schedorhinotermes javanicus, with particular attention to the form of the seminal vescicles, to their contenute, and to the testicle's activity.

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Résumé Nous avons étudié la conformation des organes males de quelques castes et stades deReticulitermes lucifugus et des ailes dePsammotermes assuanensis, Coptotermes sj?stedti, Schedorhinotermes javanicus, en donnant une particulière attention à la forme des vésicules séminales, à leur contenu et à l'activité du testicule.

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Questa nota rappresenta l'ultimo dei nostri lavori che il prof. CarloJucci ha riveduto ed approvato per la stampa. A Lui la dedichiamo, grati per l'insegna mento datoci e per l'essempio costante di dedizione al lavoro.     

Immersion survival differs among three Diabrotica species

Soil dwelling invertebrates including insects and their larvae are subjected to severe oxygen limitations when the soil becomes saturated or covered by water. Differential survival of this stress may in part explain ecological range of a species and could lead to cultural control methods for economically important species. We tested immersion survival for larvae of three species of Diabrotica (viz., D. balteata LeConte, D. undecimpunctata undecimpunctata Mannerheim, and D. virgifera virgifera LeConte). Groups of larvae were submersed in conditioned, hypoxic (dissolved oxygen <0.3 ppm) tap water, held at 10, 15, 20, or 25 °C, and periodically removed and assayed for survivorship. We found that time to 50% mortality (LT₅₀) differed significantly between species. Third instar D. u. undecimpunctata were most sensitive to immersion at 25 °C (LT₅₀=9 h), D. balteata were intermediate (LT₅₀=15 h) and D. v. virgifera larvae were least sensitive (LT₅₀=23 h). Second instar D. v. virgifera were significantly more tolerant of immersion than the other species (LT₅₀=56 h versus 15 h for D. u. undecimpunctata and 11 h for D. balteata). Mortality during immersion corresponds with the build up of lactic acid. Survivorship for all species increased with decreasing temperature. The use of flooding in rootworm management is briefly discussed.     

Influence of acetate on the growth of Candida utilis in continuous culture

Candida utilis was grown on acetate in chemostat cultures that were, successively, carbon and ammonia-limited (30° C; pH 5.5). With carbon(acetate)-limited cultures, the specific rate of oxygen consumption (q _{O 2}) was not a linear function of the growth rate but was markedly stimulated at the higher dilution rates, thus effecting a marked decrease in the Y _O value. This increased respiration rate, and decreased yield value, correlated closely with a marked increase in the extracellular acetate concentration. Under ammonia-limiting conditions, very low Y _O values were found, generally comparable with those found with carbon-limited cultures growing at the higher dilution rates, but these varied markedly with the extracellular acetate concentration. Thus, when the unused acetate concentration was raised progressively from about 5 g/l to about 21 g/l, the Y _O value decreased non-linearly from 11.4 to 5.8. When the extracellular acetate concentration was further increased to 25 g/l, growth was inhibited and the culture washed out. This relationship between respiration rate and the extracellular concentration of unused acetate was also markedly influenced by the culture pH value. Thus, with a fixed extracellular acetate concentration (16±2g/l) and dilution rate (0.14 h^–1), lowering the culture pH value progressively from 6.9 to 5.1 effected a marked and progressive increase in the respiration rate. Further lowering of the culture pH to 4.8, however, caused a complete collapse of respiration. In contrast to this situation, progressively lowering the pH value of an acetatelimited culture from 6.9 to 4.5 affected only slightly the culture respiration rate, and growth was possible even at a pH value of 2.5. These results are discussed in the context of the possible mechanisms whereby acetate exerts its toxic effect on the growth of C. utilis.     

Caste- and development-associated gene expression in a lower termite

Background  

Social insects such as termites express dramatic polyphenism (the occurrence of multiple forms in a species on the basis of differential gene expression) both in association with caste differentiation and between castes after differentiation. We have used cDNA macroarrays to compare gene expression between polyphenic castes and intermediary developmental stages of the termite Reticulitermes flavipes.     

Analysis of Extensive [FeFe] Hydrogenase Gene Diversity Within the Gut Microbiota of Insects Representing Five Families of Dictyoptera

We have designed and utilized degenerate primers in the phylogenetic analysis of [FeFe] hydrogenase gene diversity in the gut ecosystems of roaches and lower termites. H₂ is an important free intermediate in the breakdown of wood by termite gut microbial communities, reaching concentrations in some species exceeding those measured for any other biological system. The primers designed target with specificity the largest group of enzymatic H domain proteins previously identified in a termite gut metagenome. “Family 3” hydrogenase sequences were amplified from the guts of lower termites, Incisitermes minor, Zootermopsis nevadensis, and Reticulitermes hesperus, and two roaches, Cryptocercus punctulatus and Periplaneta americana. Subsequent analyses revealed that all termite and Cryptocercus sequences were phylogenetically distinct from non-termite-associated hydrogenases available from public databases. The abundance of unique sequence operational taxonomic units (as many as 21 from each species) underscores the previously demonstrated physiological importance of H₂ to the gut ecosystems of these wood-feeding insects. The diversity of sequences observed might be reflective of multiple niches that the enzymes have been evolved to accommodate. Sequences cloned from Cryptocercus and the lower termite samples, all of which are wood feeding insects, clustered closely with one another in phylogenetic analyses to the exclusion of alleles from P. americana, an omnivorous cockroach, also cloned during this study. We present primers targeting a family of termite gut [FeFe] hydrogenases and provide results that are consistent with a pivotal role for hydrogen in the termite gut ecosystem and point toward unique evolutionary adaptations to the gut ecosystem.     

Respiration Rate of Stream Insects Measured <Emphasis Type="Italic">in situ</Emphasis> Along a Large Altitude Range

Field studies of respiration in stream insects are few in comparison with laboratory studies. To evaluate the influence of temperature and oxygen along altitudinal gradients we measured the respiration rate of fully acclimatized larval Trichoptera, Plecoptera and Ephemeroptera under similar field conditions in streams from 400 to 3800 m above sea level in tropical Ecuador. Mean active respiration rates of the animals at 3800 m were approximately half of those at 400 m. Trichoptera showed a slightly larger difference in respiration with altitude than Ephemeroptera. Comparative respiration measurements at 100 and 50% oxygen saturation indicated that highland animals reduced their oxygen uptake more than their counterparts in the lowland when oxygen availability decreased. The temperature response of respiration calculated between the insect assemblages at different altitudes showed a mean assemblage Q₁₀−value of 1.50. Trichopteran larvae had a slightly stronger temperature response (Q₁₀ of 1.68) than ephemeropterans (Q₁₀ of 1.30). These community Q₁₀-values are considerably lower than the mean value of 2.36 found in single species in the laboratory. The weak community-wide response of respiration to temperature in tropical streams is probably due to full acclimatization of the component species to stable and narrow temperature ranges. Adaptations to the low oxygen availability at high altitude probably consist of a suite of genetic physiological and behavioural features.     

Antioxidant enzyme activities in subcellular fractions of larvae of the black swallowtail butterfly,Papilio polyxenes

The black swallowtail butterfly, Papilio polyxenes, larvae are specialized feeders of pro-oxidant rich plants of Apiaceae and Rutaceae. An important defense against toxic forms of oxygen species generated by ingestion of the pro-oxidants, are the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), GSH-dependent glutathione peroxidases (selenium-dependent glutathione peroxidase [GPOX] and peroxidase activity of selenium-independent glutathione-S-transferase [GT_px]), and glutathione reductase (GR). The subcellular distribution of these enzymes in black swallowtail larvae was investigated and was found to resemble the patterns described for larvae of two other lepidopteran species: the southern armyworm, Spodoptera eridania, and the cabbage looper, Trichoplusia ni. The confinement of SOD in the cytosol and mitochondria was typically eukaryotic, but the relative proportion (1:1) was markedly different from the mammalian pattern (4:1; cytosol:mitochondria). The most obvious difference between the black swallowtail and other lepidoptera as a group, and mammalian species, is in very wide intracellular distributions of CAT, GTpx, and GR in insect species. Insects possess very low levels of a GPOX-like activity which reduces both H₂O₂ and organic peroxides. Consequently, insects have elaborate activities with a wide subcellular distribution of both CAT which decomposes H₂O₂, and GTpx which decomposes organic peroxides. The reduction of peroxides is dependent on GSH, which in this process is oxidized to GSSG. GR which reduces GSSG to GSH is also of wide subcellular distribution, analogous to the distribution pattern of GTpx.     

Cry2A toxins from <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> expressed in insect cells are toxic to two lepidopteran insects

The cry2Aa and cry2Ab genes from a Brazilian Bacillus thuringiensis strain were introduced into the genome of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in order to evaluate the heterologous proteins expression in insect cells and their toxicity to different insects. The recombinant viruses (vAcCry2Aa and vSynCry2Ab) were amplified in Trichoplusia ni (BTI-Tn5B1-4) cells and used to infect Spodoptera frugiperda larvae. Total extracts from S. frugiperda infected with the recombinant viruses were analysed by SDS-PAGE, which detected the presence of polypeptides around 65 kDa. Cuboid-shaped protein crystals were observed in insect extracts by light and scanning electron microscopy. Bioassays, using the heterologous proteins showed toxicity against second instar A. gemmatalis larvae (Cry2Aa) with a LC₅₀ of 1.03 μg/ml and second instar S. frugiperda larvae (Cry2Ab) with a LC₅₀ of 3.45 μg/ml. No toxic activity was detected for Aedes aegypti and Culex quinquenfaciatus.     

Species composition and aspects of the biology of Orectolobiformes from Indonesian waters

The biological aspects of members of the order Orectolobiformes exploited in Indonesian waters are given. Seven species belonging to five families were recorded in the catches at various landing sites in southern Indonesia. Of these, Chiloscyllium punctatum was the most abundant species landed, contributing >50% of the number of orectolobiforms recorded. The biological data obtained varied greatly between the species listed. The total length (L_T) at maturity for some species, e.g. C. punctatum and Nebrius ferrugineus, varied from that which has been previously recorded for those species in other regions. This highlights the need for regional‐specific biological data for fisheries managers and conservation assessors.     

Ventilatory accommodation of changing oxygen demand in sciurid rodents

Summary Ventilation was measured across a range of O₂ consumption rates in four sciurid rodents: Tamias minimus (47 g), Spermophilus lateralis (189 g), S. beecheyi (531 g), and Marmota flaviventris juveniles (1054 g) and adults (2989 g). Maximum thermogenic oxygen consumption was measured for all but adult M. flaviventris. Aerobic scopes (maximum/minimum O₂ consumption rates) were 4.6, 3.8, 5.4, and 4.8 in T. minimus, S. lateralis, S. beecheyi, and juvenile M. flaviventris, respectively. Aerobic scope was at least 4.1 in adult M. flaviventris. Ventilatory accommodation of changing O₂ consumption rate was qualitatively similar in the four species, with the bulk of accommodation resulting from changes in minute volume. Nevertheless, there were significant differences in the relative importance of frequency, tidal volume, and O₂ extraction in accommodation. In all species, frequency and minute volume were strongly correlated to O₂ consumption rate. Tidal volume was significantly correlated to O₂ consumption rate in T. minimus and S. beecheyi, but not in the other species. Oxygen extraction was not significantly correlated to O₂ consumption rate in any species. Analysis of factorial ventilation changes across a standardized 3.8-fold change in O₂ consumption rate revealed significant differences among species in frequency and O₂ extraction, but not in tidal or minute volume. When compared to a generalized allometry for mammalian resting ventilation, the four sciurid species had consistently lower respiration frequency and higher O₂ extraction than predicted, perhaps because the sciurid measurements were made on unrestrained animals. There was no indication that ventilation constrained maximum O₂ consumption rate.Abbreviations BMR basal metabolic rate - BTPS body temperature and pressure saturated - EO₂ oxygen extraction - f respiration frequency - MMR minimal metabolic rate - RH relative humidity - STPD standard pressure and temperature, dry - T _a ambient temperature - T _b body temperature - minute volume - tidal volume - maximum rate of oxygen consumption