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.     

The depletion of starch from the sapwood of the ash (Fraxinus excelsior) and its relation to attack by powder-post beetles (Lyctus spp.)

The depletion of starch in the living sapwood of ash was examined as a possible means of rendering converted timber immune from attack by Lyctus (powder-post beetle).
Observations on disks of timber kept under controlled conditions showed that depletion is conditioned by access of oxygen; thus although in the standing tree depletion proceeds from without inwards, it can be induced in any part of the sapwood, and in any direction, by permitting access of oxygen, i.e. there is no polarity in depletion. The optimum temperature range for depletion in ash is from 31 to 36 C.: above 45 C. death of the cells may interrupt depletion.
The presence of β-indoly acetic acid does not influence rate of depletion. Reformation of the starch in the depleted wood in the presence of cane sugar could not be induced. The enzyme concerned in mobilization of the starch appears to be a labile one with an optimum in the neighbourhood of 40 C. and to be produced during the active respiration of the cells, starch depletion ceasing when oxygen is withdrawn.
In transversely cut disks the rate of respiration at 33 C. ceases to be proportional to the volume of tissue after a thickness of about 6 mm. has been attained. At 20 C. disks 10 mm. thick may be evenly depleted. Infestation experiments upon timber undergoing depletion showed that the attack by Lyctus is circumscribed by starch-level and not by total nitrogen or soluble sugars.
Under correct conditions of kilning, 1 in. sapwood plank can be rendered starch-free in about 20 days: with larger sizes depletion is uncertain and probably uneconomic.
The methods of starch and sugar analysis used in the work are appended.     

中国和越南苔类植物新记录种——柏氏细鳞苔

报道了采自中国广西和越南北部地区细鳞苔属新记录种——柏氏细鳞苔[Lejeunea patersonii(Steph.)Steph.]。该种的主要特征为侧叶顶端圆形或钝形,叶边缘具圆齿;腹叶小,远生,宽为茎的1~2倍;叶细胞角质层平滑,三角体不明显或中等大,中部球状加厚缺。该研究对柏氏细鳞苔与其相似种进行了细致的比较讨论,并对柏氏细鳞苔原有的地理分布信息进行了更正,重新确认了该种的地理分布。     

The moisture content of timber in relation to attack by Lyctus powder-post beetles

The relation between moisture content of oak sapwood and rate of development of Lyctus brunneus has been investigated at 23C. Oviposition took place normally in samples of various moisture contents between 5.5 and 23.5%. The eggs hatched in wood of 7.7% moisture content, but not of 61% moisture content, although the embryos developed fully. The rate of gain in weight of young larvae increased to a maximum as the moisture content of the wood rose to about 14.2% and then fell again. The rate of development from egg to adult followed a somewhat similar curve with a maximum at 16% moisture content. At all moisture contents the first male emerged a few days earlier than the first female. The average weight of the male beetles was less and their moisture content greater than those of the corresponding females. The average weight of the beetles showed a tendency to increase at moisture contents of the wood above 97%. The average moisture content of the males was fairly constant up to 156% moisture content of the wood, but that of the females rose slowly as the moisture content of the samples increased. In wood of 15.6% moisture content at 23C. the minimum period of development from egg to adult was 167 days; at 14.2% moisture content and 27.5 C. this was reduced to 142 days. Green timber was shown to be liable to infestation as soon as a superficial skin was formed of a suitable moisture content; the upper limiting moisture content is probably the fibre saturation point. Control of moisture content of timber cannot be achieved sufficiently easily for it to become an important method for the control of Lyctus infestation.     

Orientation of flying male Anobium punctatum (Coleoptera: Anobiidae) to sex pheromone: separating effects of visual stimuli and physical barriers to wind

Abstract. Flying male woodworm, Anobium punctatum , are able to locate a source of female pheromone offered as a point source but land more quickly if the same odour source is presented on a model 'tree' (cylinder). We tested the response to a two-dimensional black 'tree' marked as a silhouette on the upwind screen of the wind tunnel, with or without a hidden upwind barrier to the wind. The beetles responded equally to pheromone presented on a visual silhouette with wind barrier and to the hidden upwind wind-barrier alone, suggesting that the wind-barrier itself has a significant effect on insect orientation and landing: visual stimuli do not add to the landing response if the barrier is present. However, without the barrier upwind, landing was faster when the visual stimulus was present than without. This is the third forest-living species to be shown to respond in this way, which suggests this phenomenon may be more widespread. The possibility that this phenomenon is present in other, non-forest, phytophagous insects, their predators and parasitoids is discussed.     

The toxic effects of bis (tributyltin) oxide on the rat thoracic aorta.

The toxic effects of bis (tributyltin) oxide (TBTO) on the ultrastructure and permeability of rat thoracic aorta were studied electron microscopically and the accumulation sites of tin were determined with an X-ray microanalyzer. Male Wistar rats received 0.05ml/kg of TBTO as an emulsion in 1 ml of distilled water through a stomach tube. After time intervals of 2, 4, 6, 8, 10, 12 h after intubation, thoracic aortae were isolated and prepared for electron microscopy. Marked swelling of mitochondria in the aortic endothelial cells appeared at 4 h after TBTO treatment. By x-ray microanalysis, tin L-alpha peaks (3.44 keV) were obtained from these swollen mitochondria. Subendothelial edema progressed between 6 and 8 h after TBTO treatment. By tracer experiment, it was seen that large amounts of peroxidase reaction products filled the expanded subendothelial space. At 12 h after TBTO treatment, degenerative changes of the endothelial cells were prominent. These results indicated that orally administered TBTO accumulated in the mitochondria of the endothelial cells of thoracic aorta. The direct toxic effects of TBTO on mitochondria might induce severe damage to the endothelial cells and cause disturbance of the permeability barrier function of the endothelial layer and subendothelial edema.     

How does the scorpionEuscorpius flavicaudis (Deg.) manage to survive in Britain?

Field observations at Sheerness suggest thatE. flavicaudis is night-active: it fluoresces strongly in ultra-violet light. Aktograph experiments demonstrated a marked circadian rhythm of noctural locomotory activity whose free-running period in constant light is 24.7 h. In darkness, the free-running period is variable. The rate of transpiration is not unduly low compared with that of other scorpions, as might have been expected wereE. flavicaudis day-active. It is argued that the survival of this species in southern England does not involve any special physiological adjustments since most if not all species of scorpions are able to withstand freezing temperatures.     

Relationships among membranes in plastids of the red algaNitophyllum punctatum (Stackh.) Grev.

Summary The fine structure of plastids in the early stages of differentiation has been studied during the carposporogenesis of the red algaNitophyllum punctatum (Stackh.) Grev. A membranous body has been found in the plastidial matrix, which shows connections either with thylakoids, or with the plastidial genophore. More than one membranous body may be present and in some instances they show a morphological relationship also with the plastidial limiting membranes. The presence of such bodies has been observed also in fully differentiated plastids in a number of other red algae currently under study.It has been shown that the plastidial envelope may release in the matrix vesicles that give rise to the single thylakoids typical of the red algal plastids.The research project received the financial support of Ministero della Pubblica Istruzione (Roma).     

The toxicity and sublethal effects of p,p'-DDT and dieldrin to Aglais urticae (L.) (Lepidoptera: Nymphalidae) and Chorthippus brunneus (Thunberg) (Saltatoria: Acrididae)

Single topical doses of pure p,p'-DDT and dieldrin (HEOD) were given to the last larval instars of Chorthippus brunneus and Aglais urticae bred under standardized conditions. The symptoms of acute toxicity followed the same pattern in all four insect-insecticide combinations, and there was a clear inverse correlation between the toxicity of absorbed insecticide and concentration of total lipid when dosed, both being dependent on age. It is probable that developmental changes in concentration of total lipid cause changes in resistance to the lipophilic and hydrophobic organochlorine insecticides. These results illustrate the importance of using the amount of insecticide absorbed rather than the amount applied for the interpretation of data. Unabsorbed insecticide was estimated by methanol rinses; there was some evidence that these remove a small proportion of absorbed insecticide from A. urticae, but not from C. brunneus. Sublethal effects tend to occur at times of lipid mobilization. There was considerable correlation between insecticide persistence and the occurrence of sublethal effects. Both species convert DDT to DDE readily, although only A. urticae retains DDE for long. No obvious effects were detected in C. brunneus. The only effect in A. urticae was retarded pupation when a large dose was applied fairly near the time of pupation. Dieldrin was more toxic and persistent, and caused latent toxicity, deformation of adults, sterility, and hyperactivity of adults in A. urticae, although there were no apparent effects on C. brunneus except for a possible decrease in the time to moult. Neither insecticide affected water uptake in C. brunneus eggs, and development continued normally up to hatch. The hatched nymphs were unaffected by DDT, most of which was in the egg membranes, and the nymphs rapidly metabolized the rest to DDE. Dieldrin did kill nymphs at eclosion. There was no evidence of effects on the genetic constitution of future generations, but the survival and reproductive abilities of individuals can obviously be affected. I conclude, from two measures of the amount of insecticide acquired by A. urticae in the field, and from the amount required to produce sublethal effects, that A. urticae is probably, with present levels of contamination, unaffected by DDT or dieldrin outside sprayed areas, but more information is needed on other possible effects, and on amounts found in wild specimens. I discuss how far this conclusion applies to other insect species.     

不同异构体的氯氰菊酯对德国小蠊的毒力

氯氰菊酯的顺式或反式、或其混合体对德国小蠊的生物活性，在50～500PPm浓度范围内，击倒中浓度由原369ppm降至49～164ppm；高温稳定性中的击倒中时，由原10～18分降至4～10分。     

Thermal tolerance and geographical range size in the Agabus brunneus group of European diving beetles (Coleoptera: Dytiscidae)

Aim Within clades, most taxa are rare, whilst few are common, a general pattern for which the causes remain poorly understood. Here we investigate the relationship between thermal performance (tolerance and acclimation ability) and the size of a species’ geographical range for an assemblage of four ecologically similar European diving beetles (the Agabus brunneus group) to examine whether thermal physiology relates to latitudinal range extent, and whether Brown’s hypothesis and the environmental variability hypothesis apply to these taxa. Location Europe. Methods In order to determine the species tolerances to either low or high temperatures we measured the lethal thermal limits of adults, previously acclimated at one of two temperatures, by means of thermal ramping experiments (± 1°C min^?1). These measures of upper and lower thermal tolerances (UTT and LTT respectively) were then used to estimate each species’ thermal tolerance range, as total thermal tolerance polygons and marginal UTT and LTT thermal polygons. Results Overall, widespread species have higher UTTs and lower LTTs than restricted ones. Mean upper lethal limits of the Agabus brunneus group (43 to 46°C), are similar to those of insects living at similar latitudes, whilst mean lower lethal limits (?6 to ?9°C) are relatively high, suggesting that this group is not particularly cold‐hardy compared with other mid‐temperate‐latitude insects. Widespread species possess the largest thermal tolerance ranges and have a relatively symmetrical tolerance to both high and low temperatures, when compared with range‐restricted relatives. Over the temperature range employed, adults did not acclimate to either high or low temperatures, contrasting with many insect groups, and suggesting that physiological plasticity has a limited role in shaping distribution. Main conclusions Absolute thermal niche appears to be a good predictor of latitudinal range, supporting both Brown’s hypothesis and the environmental variability hypothesis. Restricted‐range species may be more susceptible to the direct effect of climate change than widespread species, notwithstanding the possibility that even ‘thermally‐hardy’, widespread species may be influenced by the indirect effects of climate change such as reduction in habitat availability in Mediterranean areas.     

An easy,rapid and inexpensive method to monitor tributyltin (TBT) toxicity in the laboratory

Tributyltin (TBT) contamination remains a major problem worldwide. Many laboratories are committed to the development of remediation methodologies that could help reduce the negative impact of this compound in the environment. Furthermore, it is important to have at hand simple methodologies for evaluating TBT toxicity in the laboratory, besides the use of complex and costly analytical instrumentation. With that purpose, a method was adapted that is based on the inhibition of growth of an indicator strain, Micrococcus luteus ATCC 9341, under TBT. Different types of matrices, of TBT concentrations and sample treatments were tested. The results herein reported show that the bioassay method can be applied for both aqueous and soil samples and also for a high range of TBT concentrations (at least up to 500 μmol/L). Besides being cheap and easy to perform, it can be performed in any laboratory. Additionally, one possible application of the method to monitor TBT degradation is presented as an example.