Growth and metabolism of the hyperiid amphipod, Themisto japonica (Bovallius), reared in the fluctuating and constant temperatures in the laboratory

In order to assess the effect of large daily changes of temperatureon the growth and metabolism (oxygen consumption) of a verticalmigrator, Themisto japonica, specimens collected from the fieldwere reared in the laboratory under a fluctuating temperatureregime (1–15°C, with an integrated daily mean of 8°C)and at constant temperature (8°C) as a control. To facilitateanalysis, two predictive models were constructed and tested.One (IDMT model) is based on the integrated daily mean temperature,and the other (IDMR model) on the integrated daily mean rate.The IDMT model predicts that vertical migration causes no differencein either daily growth or daily metabolism. The IDMR model suggeststhat daily growth will increase by a factor of 1.04, and metabolismby a factor of 1.58. Because of the small difference betweenthe models in respect of growth, the experimental results areconsonant with either. Experiments support the IDMT model resultsfor daily metabolism. The results are discussed in light ofexisting views of physiological rate processes of vertical migratorsand regarding the adaptive theory of vertical migration.     

Assessment of higher insect taxa as bioindicators for different logging-disturbance regimes in lowland tropical rain forest in Sabah, Malaysia

One of the serious environmental problems since the 1980s has been the conflict between the high rate of deforestation and maintenance of healthy ecosystem services and biological values in tropical forests. There is an urgent demand for setting up an appropriate environmental assessment to keep healthy ecosystem functions and biodiversity along with sustainable forest use based on ecology. In this study, we tried to assess logging-disturbance effects on the abundances of several flying insect groups (higher-taxon approach) in lowland tropical rain forest (Deramakot Forest Reserve, Sabah, Malaysia), while considering seasonal changes and vertical forest stratification. The season was the most important factor affecting the abundances of all the insect groups. Effects of logging disturbance were prominent in the understorey but obscure in the canopy. Changes in physical conditions caused by logging—possibly an increased evaporation due to solar radiation—may have decreased the abundance of desiccation-sensitive insects, especially in the understorey. There are also two probable reasons for the difference between events in the understorey and those in the canopy: (1) noise effects of various physical, environmental factors may have obscured insect responses to logging disturbance in the canopy; (2) higher spatio-temporal variation in quality and quantity of living food resources—such as leaves, flowers and fruits—provided in the canopy may have affected the abundance of their consumer insects independently of logging disturbance. Thus, this study suggests that the abundance of some insect groups at higher-taxon level, especially in the understorey, can be used as bioindicators for assessing effects of logging disturbance on the forest ecosystem.     

Intrinsic optimum temperature of the diamondback moth and its ecological meaning

Temperature can notably affect development rate and intrinsic rate of increase of the diamondback moth, Plutella xylostella L. The intrinsic rate of increase is usually regarded as a good measure of fitness in insects, and the constant temperature at which the intrinsic rate of increase reaches its maximum is defined as the "optimal" temperature for an insect species to survive. The estimates of optimal temperature for some insects and mites are ~30°C. However, the Sharpe-Schoolfield-Ikemoto model provides an estimate about the intrinsic optimum temperature at which the probability of an enzyme being in the active state is maximal. The intrinsic optimum temperature is considered to be the most suitable temperature for an insect species to survive. The estimates of intrinsic optimum temperature for some insects and mites are ~20°C. The optimal temperature and the intrinsic optimum temperature of the diamondback moth were estimated in the current study. The former estimate is 28.4 (95% CI: 26.2-28.8°C), whereas the latter estimate is 19.4°C (95% CI: 17.9-20.5°C). Considering the daily average air temperatures during the peaks of the diamondback moth in China, the intrinsic optimum temperature of 19.4°C might represent the most suitable temperature for this insect to survive. We also discussed whether it is sounded to use the intrinsic rate of increase as the fitness. Because the intrinsic rate of increase cannot reflect the density-dependence of population and the trade-off between individual body mass and population size, it is inappropriate to equate these two concepts.     

有效积温Sine函数拟合模型及其应用

阐述了昆虫物候分析的SSPM模型（single sine phonological model）计算方程和过程,该模型采用Sine函数拟合每天温度变化,并利用积分,获取每天有效积温和一定时间内日度累积值.SSPM重要的参数有发育起点温度和上限温度,参与模型计算包括日最高气温和日最低气温2个输入值,在输入值和参数值组合条件下,模型有6个不同计算方程.以棉铃虫（Helicoverpa armigera）为例,介绍了SSPM在昆虫发育历期分析过程,简单表述了模型预测功能.随自动化气象站分布密度增加和Internet技术的发展,模型在区域化害虫管理中有着重要的应用前景.     

Within-person changes in salivary testosterone and physical characteristics of puberty predict boys' daily affect

Recent investigations highlighted the role of within-person pubertal changes for adolescents' behavior. Yet, little is known about effects on adolescents' daily affect, particularly regarding the hormonal changes underlying physical changes during puberty. In a study with 148 boys aged 10 to 20 years, we tested whether within-person physical and hormonal changes over eight months predicted everyday affect fluctuations, measured with experience sampling. As expected, greater within-person changes in testosterone (but not in dehydroepiandrosterone) were associated with higher affect fluctuations in daily life. Additionally, greater physical changes predicted higher affect fluctuations for individuals in the beginning of puberty. The findings demonstrate the relevance of physical and hormonal changes in boys' affective (in)stability.     

The Influence of Diurnal Temperature Variation on Degree-Day Accumulation and Insect Life History

Ectotherms, such as insects, experience non-constant temperatures in nature. Daily mean temperatures can be derived from the daily maximum and minimum temperatures. However, the converse is not true and environments with the same mean temperature can exhibit very different diurnal temperate ranges. Here we apply a degree-day model for development of the grape berry moth (Paralobesia viteana, a significant vineyard pest in the northeastern USA) to investigate how different diurnal temperature range conditions can influence degree-day accumulation and, hence, insect life history. We first consider changes in diurnal temperature range independent of changes in mean temperatures. We then investigate grape berry moth life history under potential climate change conditions, increasing mean temperature via variable patterns of change to diurnal temperature range. We predict that diurnal temperature range change can substantially alter insect life history. Altering diurnal temperature range independent of the mean temperature can affect development rate and voltinism, with the magnitude of the effects dependent on whether changes occur to the daily minimum temperature (Tmin), daily maximum temperature (Tmax), or both. Allowing for an increase in mean temperature produces more marked effects on life history but, again, the patterns and magnitude depend on the nature of the change to diurnal temperature range together with the starting conditions in the local environment. The study highlights the importance of characterizing the influence of diurnal temperature range in addition to mean temperature alone.     

The role of intra-specific mechanisms and predation in regulating the numbers of the lime aphid,Eucallipterus tiliae L.

Summary Analysis of changes in numbers of the lime aphid, Eucallipterus tiliae L., reveals that there is an overcompensated density dependent factor acting within years, and an inverse density dependent factor acting between years. Because of its effect on the aphid's rate of development and reproduction the variation in temperature from year to year acts as a density disturbing factor.There is no evidence from laboratory experiments to suggest that the quality of its food influences the numbers of the lime aphid. However, qualitative changes in the aphid following period of aphid abundance are shown to be important in the overcompensated density dependent response. The more prevalent insect predators influence the regulating process as they eat most of the aphids that remain after an aphid population has declined from a very high level of abundance. Their action results in a more overcompensated response than would occur in their absence.     

A guide to the use of the exuding-stylet technique in phloem physiology

The use of exuding stylets holds considerable promise for the investigation of sieve-tube physiology. However, largely because of difficulties in cutting insect stylets, the technique has been applied to only a few plant species. Based on our experience, a comparison is made of the available means of obtaining sieve-tube exudate from the exuding stylets of phloem-feeding insects, including aphids, scale and mealybugs. Forty-one plant species and approx. 35 insect species were tested for their ability to provide stylet exudate. Stylets on all but a few of the plant species tested yielded at least some exudate, but the success rate and duration of exudation on many species were unsatisfactory for detailed investigations of phloem transport. Plant species appears to be the most important factor for obtaining reliably exuding stylets, although the size of the insect species used and the physiological condition of the plant are also important variables. Armored scale provide a simple and reliable source of exuding stylets, but are impractical for most experimental purposes. Radio-frequency microcautery of aphid stylets was substantially the most effective means of cutting stylets. Instructions are provided for constructing a microcautery unit at minimal expense, using a citizen's band radio as the radio-frequency source.Abbreviations CB citizen's band - R.F. radio frequency     

Cyberkelp: an integrative approach to the modelling of flexible organisms

Biomechanical models come in a variety of forms: conceptual models; physical models; and mathematical models (both of the sort written down on paper and the sort carried out on computers). There are model structures (such as insect flight muscle and the tendons of rats' tails), model organisms (such as the flying insect, Manduca sexta), even model systems of organisms (such as the communities that live on wave-swept rocky shores). These different types of models are typically employed separately, but their value often can be enhanced if their insights are integrated. In this brief report we explore a particular example of such integration among models, as applied to flexible marine algae. A conceptual model serves as a template for the construction of a mathematical model of a model species of giant kelp, and the validity of this numerical model is tested using physical models. The validated mathematical model is then used in conjunction with a computer-controlled tensile testing apparatus to simulate the loading regime placed on algal materials. The resulting information can be used to create a more precise mathematical model.     

Shifts in breeding habitat selection behaviour in response to population density

We tested whether mountain pine beetles Dendroctonus ponderosae, an insect herbivore that exhibits outbreak population dynamics, modifies its habitat selection behaviour in response to density‐dependent environmental shifts. Using an individual‐based habitat selection model, we formulated predictions of how beetle population density will influence breeding habitat selectivity. Our model predicted that beetles should be more selective at intermediate densities than at low or high densities. The mechanisms influencing optimal selectivity differed between low and high density populations. In low density populations, breeding site availability was the primary factor affecting selectivity, whereas intraspecific competition and the reliability of habitat quality cues were important in high density populations. We tested our model predictions in natural populations that encompassed a range of beetle population densities. Our empirical findings supported the two key predictions from our model. First, habitat quality was more variable in high density populations. Second, individuals in high density populations were less selective compared to beetles from intermediate density populations. Our results demonstrate that beetles alter their habitat selection behaviour in response to density‐dependent shifts. We propose that the behavioural changes we identified may influence the rate at which beetle populations transition between density states.     

昆虫发育速率与温度关系的数学模型研究

一、前言 昆虫生长发育过程中,温度是影响最显著的一个生态因子。对于昆虫发育历期与环境温度间的定量关系,前人提出过不少经验公式,分别在不同程度上反映了发育历期与温度间的密切依赖关系。     

Dielectric properties of insect tissues

In order to explain some effects of microwave irradiation on insects it is necessary to consider a mathematical model. The knowledge of dielectric properties of a typical insect tissue is crucial for such a model. A method based on shift of resonant frequency and of quality factor measurement in a resonator both before and after the insertion of samples was used. The method (measurements at a frequency of 2375 MHz) has been described in detail. A large number of measurements were performed on different kinds of typical insect tissues (cuticle, fat body, muscles, reproductive organs and eggs) for their dielectric properties. The values obtained compare well to those reported in the literature for some mammals. Differences seemed to depend on different water-to-fat content ratios. However, no simple dependence on the water content was found. Values obtained from insect tissue material have been discussed in detail.     

Morphologic changes in the thymus and lymphoid nodules of the appendix of the white rat subjected to increasing physical loads

By means of histological and morphometrical methods the thymus and appendage have been studied in male white rats subjected to a dosed physical loading (swimming). The physical loading is accompanied with essential changes in structure and cell composition of the immunogenic organs. The rate and character of the changes depend on the adaptability level of the animal's organism to the physical loading. At adaptation to the loading, the process of age involution of the thymus decelerates, amount of lymphoid nodules in the appendage increases, comparing the control parameters, contents of lymphocytes noticeably increase in all zones of the lymphoid nodules. When adaptation to the physical loading is not sufficient, the rate of the thymus involution sharply increases, while in the appendage the number of the lymphoid nodules decreases. However, in some animals at a sharp involution of the thymus, the changes in the appendage do not differ from the control ones.     

Insect community organisation in estuaries: the role of the physical environment

Insects are reportedly uncommon in marine habitats and, from a spatial/temporal intercomparison perspective, estuaries are among the least studied. We examined the natural variability seen among insect community organisation in estuaries on both sides of the North Atlantic, and evaluated the role of their physical environments. Community composition was found to be strongly influenced by three physical factors: estuary size, the degree of inundation by incoming tides, and substrate size/stability. Insects formed a significant proportion (17–54%, by numbers) of the benthic community of coarse-grained-substratum estuaries, and species richness increased with estuary size. Nymphs/larvae of mayflies, stoneflies, caddisflies, elmid beetles and chironomids dominated channel sites inundated by up to 25% of all incoming tides, but a gradual loss in species richness occurred downstream. However, even the most seaward sites supported high insect densities (up to 25 016 and 5433 m⁻², supporting 26 and 4 species, at sites inundated by 75 and 100% of all incoming tides, respectively). Sites covered by tides for between 3 and 5 h twice daily were dominated by orthocladine chironomids, especially of the genus Orthocladius . Chironomid larvae contribute significantly to the diets of some coastal fish species, particularly juvenile flounder and sticklebacks. We present a schematic model summarising the relationships between estuary size, degree of inundation by salt water and insect community structure.     

BDNF improves axon transportation and rescues visual function in a rodent model of acute elevation of intraocular pressure

Optic neuropathies lead to blindness; the common pathology is the degeneration of axons of the retinal ganglion cells. In this study, we used a rat model of retinal ischemia-reperfusion and a one-time intravitreal brain-derived neurotrophic factor(BDNF)injection; then we examined axon transportation function, continuity, physical presence of axons in different part of the optic nerve, and the expression level of proteins involved in axon transportation. We found that in the disease model, axon transportation was the most severely affected, followed by axon continuity, then the number of axons in the distal and proximal optic nerve. BDNF treatment relieved all reductions and significantly restored function. The molecular changes were more minor,probably due to massive gliosis of the optic nerve, so interpretation of protein expression data should be done with some caution.The process in this acute model resembles a fast-forward of changes in the chronic model of glaucoma. Therefore, impairment in axon transportation appears to be a common early process underlying different optic neuropathies. This research on effective intervention can be used to develop interventions for all optic neuropathies targeting axon transportation.     

Influence of physical activity on the regulation of bone density

Using a mathematical model which relates bone density to daily stress histories, the influence of physical activities on the apparent density of the calcaneal cancellous bone was investigated. Assuming that the mechanical bone maintenance stimulus is constant for all bone tissue, bone apparent density was calculated by a linear superposition of the mechanical stimulus provided by different daily physical activities. An empirical weighting factor, m, accounted for possible differences in the relative importance of load magnitude and number of cycles in each activity. By considering hypothetical variations in body weight and occupational activity levels, the range of probable m values was established. The model was then applied to the results of two previous running studies in which calcaneal density was measured to obtain an estimate of the stress exponent parameter, m. The results indicate that stress magnitudes (or joint forces) have a greater influence on bone mass than the number of loading cycles. We demonstrate that by carefully considering the magnitudes of imposed skeletal forces and the number of loading cycles, it may be possible to design exercise programs to achieve predictable changes in bone mass.     

Understanding flying insect dispersion: Multiscale analyses of fragmented landscapes

A multiscale model was developed to simulate the rate of landing of a winged insect, the grain aphid, Sitobion avenae F. At a large scale (kilometric scale), it is convenient to use a deterministic model of their dispersion, based upon diffusion–advection–reaction partial derivative equations. At a small scale (hectometric scale), the process of site selection (‘landing’) is only partially understood, but is known to include the perception of field colour and landscape characteristics. Several hypotheses on aphids' behaviour were tested to simulate the rate of landing: the simulation was done by a cellular automata submodel under five different hypotheses on the precise organisation of the landing behaviour. We found a strong interaction between the effect of the proportion of wheat crops in the landscape and their spatial organisation. The spatial correlation between the places occupied by wheat crops appears crucial to determine the global rate of landing of the aerial insect stock. The shape of the response surface of landing rate against the proportion of surface occupied by wheat, and the spatial autocorrelation of wheat plots, appears very regular and relatively simple to model by ad hoc mathematical functions. Large scale simulations using the results of the small scale model in a diffusion–reaction equation solved numerically, showed that, on a real landscape extracted from a GIS on the whole Brittany region (western France), the spatial pattern of the aphid landing is sensitive to the hypothesis tested on their landing behaviour. This hierarchical modelling combining two different approaches at two different scales (mathematical deterministic equations on a large multi-kilometric scale, and partly stochastic cellular automata on a small hectometric scale), requires methods to validate its results in the field, in the framework of a decision support system. Such a multiscale model has a wide field of application including not only plant protection but also management and conservancy of animal species dispersing by flight.     

昆虫多状态发育的生存分析

针对昆虫种群变态发育过程,本文给出了一个多状态生存函数的模型。使用生存分析的方法对模型进行丁分析。本文还对有关的生存参数如各状态的死亡风险,发育风险,年龄特征死亡率,年龄特征发育率以及状态发育历期等进行了讨论并且给出了它们的极大似然估计值。关于马铃薯块茎蛾数值例子的分析表明所提出的摸型用来描述昆虫种群的发育过程是有效的。本文的结论可以做为组建描述昆虫种群多状发育的年龄一状态特征生命表的理论基础。     

Chemical structure, juvenile hormone activity and persistence within the insect of juvenile hormone mimics for Rhodnius prolixus.

41 chemicals were tested for juvenile hormone (JH) activity for Rhodnius prolizus by two methods of application. Several different classes of chemical were represented, viz. long chain terpenoid compounds, aryl terpenoid compounds, aryl terpenoid amines and aryl terpenoid ethers.All classes of chemical contained members which showed at least moderate activity. The most active compound was N-(2,5-dichlorophenyl)-3,7-dimethyl-2,6-octadienylamine; 0.0024 μg induced the production of an insect which was halfway between a normal adult and a complete supernumerary larva. Since several compounds with widely differing chemical groupings showed high JH activity, it is considered that overall molecular size and shape are important considerations in determining JH activity, although they do not by themselves provide a complete explanation. Some chemicals tested are specific in their JH activity to relatively few insects. JH mimic specificity is discussed and it is considered that molecular shape can explain some aspects of this phenomenon.The persistence within the insect of the JH mimics varied greatly. In general, compounds with a methyl ester group at one end and an epoxide group at the other had least persistence. The absence of one or more of these features tends to induce greater persistence. Within most classes of chemical, the members with highest JH activity tended to have least persistence and it is considered that the major factor affecting persistence with the insect is the rate of enzymic degradation of the JH mimic.     

Determination of aeration rate and kinetics of composting some agricultural wastes

This study aimed to determine the aeration rate and its kinetics in aerobic composting of agricultural wastes. For this aim compost materials were prepared by mixing grass trimmings, tomato, pepper, and eggplant wastes. Four vertical forced aeration type reactors and one vertical natural convection type reactor were manufactured to apply four different aeration rates. CO2 rate and temperature changes were recorded in three different places in the reactors. Moisture content, pH and organic material rate were recorded each day. While process-monitoring parameters (CO2, temperature, pH, moisture content) were used for interpretation of the process, organic material degradation was used for interpretation of the process success. The seven different kinetic models were applied for modeling decomposition rate to the experimental values. According to the results, four of these models were found applicable to this study. These models were analyzed with some statistical methods as root mean square error (RMSE), chi-square (chi2), and modeling efficiency (EF). According to the statistical results of these models, the best model was found as: [Formula: see text] where kT is the rate of decomposition (g VS/g VS day); T the process temperature (degrees C); Mc the daily moisture content (%wb); C the daily CO2 rate in composting reactor (%) and a, b, c, d are constants. According to the results, the highest organic matter degradation and temperature value were obtained at the aeration rate of 0.4 l air min(-1)kg(om)(-1). Thus, it could be applied to this mixed materials composting process.