bluuebunny/crossref_metadata_2025 huggingface dataset:
The changes in the T‐lymphocyte subsets in a population of Turkish children with puberty gingivitis
Authors: DEMIR TURGUT , ORBAK RECEP , TEZEL ADNAN , ÇANAKÇ VAROL , KAYA HASAN
Published: March 2008

Objective.  The aim of the study was to investigate the number of CD4 and CD8 T lymphocytes, analyse subjects with gingivitis and those without, and determine the role of T lymphocytes in the pathobiology of puberty gingivitis.

Material and methods.  Fifty individuals with and without puberty gingivitis were recruited for this study. The CD4+ and CD8+ T‐lymphocyte counts were determined using flow cytometry on the biopsy samples, and the CD4+/CD8+ ratio was calculated. At the same time, periodontal index scores were recorded to assess the periodontal status. Acquired data were analysed statistically using a paired t‐test to compare laboratory values obtained before and after the treatment in individuals with puberty gingivitis and disease‐free individuals. In addition, Pearson's correlation analysis was performed to investigate the relation between laboratory values and clinical measurements.

Results.  The CD4+/CD8 ratio in gingival tissues obtained from test group was significantly higher (P < 0.05) than that found in the gingival tissue obtained from control group. We found that the CD4+ and CD8+ lymphocyte counts continued to increase significantly (P < 0.001) and the CD4+/CD8+ ratio continued to drop significantly (P < 0.05) after treatment in test group.

Conclusions.  T lymphocytes could play a significant role in the pathobiology of puberty gingivitis
Restoration of a ponderosa pine forest increases soil CO2efflux more than either water or nitrogen additions
Authors: Selmants Paul C , Hart Stephen C , Boyle Sarah I , Gehring Catherine A , Hungate Bruce A
Published: March 2008

Ecological restoration often involves returning ecosystem structure to some predisturbance reference state, but ecosystem function must also recover if restoration efforts are to be self‐sustaining over the long term. In the south‐western United States, ponderosa pine forest structure was altered by disruption of the fire regime following Euro‐American settlement. Forest structure is now being restored to presettlement conditions through the application of thinning and burning treatments. However, the effects of these treatments on below‐ground ecosystem processes remain unclear.

We conducted a water and nitrogen (N) addition experiment in adjacent restored and unrestored ponderosa pine stands and compared soil CO2efflux in response to these treatments over a 13‐month period. Our goals were to (i) quantify water and N limitation to below‐ground carbon (C) cycling in contemporary high‐density ponderosa pine forests; and (ii) determine if restoration alleviates water and N limitations.

Restoration thinning and burning increased soil CO2efflux, along with surface soil water content, temperature and herbaceous fine root biomass, while total fine root biomass decreased as a result of restoration.

Water and N additions increased C flux from soils to a similar degree in both restored and unrestored ponderosa pine stands, but the increase was relatively small when compared to that stimulated by restoration.

Synthesis and applications.An understanding of how ecosystem processes respond to treatments designed to restore ecosystem structure is critical in ensuring the long‐term success of restoration efforts. Here we show that, although water and N stimulate C flux from soils in these semi‐arid forests, restoration treatments have a much greater effect on soil C balance than increased water and N availability by themselves. This suggests that increased quality of C inputs from a recovering understorey herbaceous community is a key component of restoring ecosystem function (e.g. below‐ground C cycling) in south‐western ponderosa pine forests.
Fitness costs associated with three mutant acetyl‐coenzyme A carboxylase alleles endowing herbicide resistance in black‐grass Alopecurus myosuroides
Authors: Menchari Y , Chauvel B , Darmency H , Délye C
Published: March 2008

Pleiotropic effects associated with genes endowing resistance to herbicides are generally predicted to reduce plant fitness. Quantifying these effects is necessary to develop management strategies against herbicide‐resistant weeds. We assessed the pleiotropic effects associated with three mutant alleles of the herbicide target enzyme acetyl‐coenzyme A carboxylase (ACCase) on plant growth and seed production in black‐grass Alopecurus myosuroides.

In each of two field experiments, black‐grass populations segregating for Leu‐1781 (five populations), Asn‐2041 (three populations) or Gly‐2078 (two populations) ACCase were produced to obtain several distinct, homogenized genetic backgrounds and to permit reliable comparisons among wild‐type, heterozygous and homozygous mutant ACCase plants grown in competition with a wheat crop.

No significant differences from wild‐type plants in vegetative biomass, height and seed production were observed in Leu‐1781 or Asn‐2041 ACCase plants.

 Over both experiments, homozygous Gly‐2078 ACCase plants displayed a significant reduction in biomass (42%), height (6%) and seed production (36%). Reduction varied with the segregating population and between field experiments.

Synthesis and applications. Our work illustrates the variation in fitness cost depending on the resistance gene, the plant genetic background and the environment. This underlines the necessity to identify the resistance gene(s) present in a weed population before designing resistance‐management strategies. Competitive crops should be effective against Gly‐2078 ACCase plants. The effect of resistant ACCase alleles on seed survival and germination needs to be studied in order to develop cultural practices creating or maximizing fitness costs in resistant plants. However, the variation of fitness cost with the environment and the weed population, as well as the likely absence of fitness cost associated with resistance genes such as Leu‐1781 ACCase, renders the success of specific cultural control practices uncertain. A solution could be a weed control programme maximizing the diversity of cultural practices and including anti‐resistance cultural practices to avoid or reduce selection for resistant ACCase alleles.
Dispersal, disturbance and the contrasting biogeographies of New Zealand’s diadromous and non‐diadromous fish species
Authors: Leathwick J. R. , Elith J. , Chadderton W. L. , Rowe D. , Hastie T.
Published: March 2008

Aim  To examine the relationship between diadromy and dispersal ability in New Zealand’s freshwater fish fauna, and how this affects the current environmental and geographic distributions of both diadromous and non‐diadromous species.

Location  New Zealand.

Methods  Capture data for 15 diadromous and 15 non‐diadromous fish species from 13,369 sites throughout New Zealand were analysed to establish features of their geographic ranges. Statistical models were used to determine the main environmental correlates of species’ distributions, and to establish the environmental conditions preferred by each species. Environmental predictors, chosen for their functional relevance, were derived from an extensive GIS database describing New Zealand’s river and stream network.

Results  In terms of geography, most diadromous species occur in a scattered fashion throughout extensive geographic ranges, and occupy large numbers of catchments of widely varying size. By contrast, most non‐diadromous species show relatively high levels of occupancy of smaller geographic ranges, and most are restricted to a few large catchments, particularly in the eastern South Island. In terms of environment, there is marked separation of diadromous from non‐diadromous species, with diadromous species generally caught most frequently in low‐gradient coastal rivers and streams with warm, maritime climates. With a few notable exceptions, most diadromous species have lower occurrence in river segments that are located above obstacles to upstream migration. Non‐diadromous species are usually caught in inland rivers and streams with cool, strongly seasonal climates, typified by a low frequency of high‐intensity rainfall events.

Main conclusions  We interpret the contrasting biogeographies of New Zealand’s diadromous and non‐diadromous species as reflecting interaction between their marked differences in dispersal ability and a landscape that is subject to recurrent, often large‐scale, natural disturbance. While both groups are likely to be equally susceptible to local, disturbance‐driven extinction, the much greater dispersal ability of diadromous species has allowed them to persist over wide geographic ranges. By contrast, the distributions of most non‐diadromous species are concentrated in a few large catchments, mostly in regions where less intense natural disturbance regimes are likely to have favoured their survival.
Endogenous sex hormones and C‐reactive protein in healthy postmenopausal women
Authors: Störk S. , Bots M. L. , Grobbee D. E. , Van Der Schouw Y. T.
Published: March 2008

Background.  Oral oestrogen replacement therapy increases levels of C‐reactive protein (CRP). CRP is an established strong predictor of cardiovascular events. It is unknown whether endogenous oestrogen levels are associated with CRP. We therefore studied the relationship between endogenous sex hormones and CRP in healthy postmenopausal women emphasizing the role of body composition as peripheral fat is both a main source of oestrogen production after menopause and an endocrine tissue with inflammatory activities.

Subjects and methods.  The study population comprised 889 women participating in the PROSPECT study, an ongoing population‐based cohort study. Information on risk factors was collected by questionnaires and clinical examination. Endogenous sex hormone levels and CRP were measured with double antibody radio immuno assay (RIA) from fasting plasma samples. In this cross‐sectional study, associations between risk factors and lnCRP were studied using linear regression models.

Results.  Increases in oestrone and free oestradiol levels and the free androgen index were related to an increase in lnCRP of 1.19, 1.23 and 1.21 mg dL−1 respectively. Body mass index (BMI), waist circumference and physical activity were strongly related to CRP levels, independent of age and other cardiovascular risk factors. Levels of all sex steroids but dehydroepiandrostenedione decreased with age. In age‐adjusted analyses, an increase in waist circumference or BMI by one quartile was associated with a 1.28‐fold and 1.26‐fold increase in CRP. The relationship between endogenous hormones and CRP was modestly attenuated but remained highly significant after adjustment for body composition, physical activity and other traditional cardiovascular risk factors.

Conclusions.  Our findings show that in postmenopausal women high levels of endogenous oestrogenic and androgenic sex steroids coincide with high CRP levels. This was only explained in part by markers of body composition or intra‐abdominal fat.
A club‐shaped hair found on the first‐instar nymphs of Schistocerca gregaria
Authors: BERNAYS E. A. , COOK A. G. , PADGHAM D. E.
Published: March 2008

A receptor found mainly on the antero‐dorsal regions of the first‐instar nymph of Schistocerca gregaria is described. The fine structure of the sensillum and its associated cells is described and its possible functions discussed in relation to its unusual structure.
The orientation of walking honeybees in odour fields with small concentration gradients
Authors: KRAMER ERNST
Published: March 2008

The behaviour of walking honeybees in small gradient odour fields was investigated by means of a simulation technique. The bee was kept in one place by a locomotion compensator (‘running sphere’). This compensator allowed for a precise reconstruction of the bee's actual locomotion on the sphere, and presented the bee with a stimulating odour whose concentration was controlled by feedback from the reconstructed locomotion. This rendered possible the application of well‐defined odour fields and revealed that: (1) honeybees are capable of finding odour sources in the absence of optical cues and with concentration gradients too small to allow tropotactic or klinotactic orientation; (2) bees are capable of memorizing odour concentrations with a high degree of accuracy; (3) this orientation system is based on a switching over from negative to positive anemotaxis at a ‘reference’ concentration; (4) this reference is a function of the odour concentration at which a sugar reward is given. The results do not support any hypothesis for an orientation system based on the detection and comparison of successive values of odour concentration. A hypothesis on the nature of the ‘reference value’ is discussed and supported by experiments.
The effect of leaf excision on the performance of Myzus persicae and Brevicoryne brassicae in relation to the nutrient treatment of the plants
Authors: van EMDEN H. F. , BASHFORD MARGRETHE A.
Published: March 2008

Two groups of brussels sprout plants of one variety given different fertilizer treatments proved ‘resistant’ and ‘susceptible’ to both Myzus persicae and Breicoryrie brassicae, as measured by aphid mean relative growth rate. The hypothesis that leaf disc would fail to reflect differences in ‘nutritionallybased’ plant resistance was confirmed with B.brussicue but not M.persicae. Both aphids grew more slowly on discs than leaves of ‘susceptible’ plants; the reverse tendency showed on ‘resistant’ material. Total:(, amino nitrogen proved poorly correlated with aphid performance. Previously published (van Emden & Bashford, 1971) equations relating individual amino acids to aphid performance gave a better fit to the results, but still failed to account for the reduced performance of the aphids on ‘susceptible’ discs.
Courtship behaviour in Meraporus gramivticola (Hymenoptera) and other Pteromalinae
Authors: BARRASS ROBERT
Published: March 2008

The courtship of Meraporus graminicola Walker is described and compared with that of other Pteromalinae. The sequence of courtship movements is characteristic of each species, and in all species studied the male's mating attempt is made not during a sequence of courtship movements but at the end of the sequence. Then the male extends its mouthparts, an action common to all species, and if there is no contact with the female's antennae a mating attempt follows.
Factors governing the induction of diapause in Ephestia elutella and Plodia interpunctella (Lepidoptera)
Authors: BELL C. H.
Published: March 2008

Diapause in fully grown larvae of Ephestia elutella and Plodia inferpunctella was induced by low temperature and short photoperiods. Light intensities below 1 lx affected the induction of diapause in both species. At 20 and 25d̀C, the critical photo‐period for E.elutella was c. 14 h, and for P.interpunctella c. 13 h. The sensitive phase in both species occurred at about the time of the fourth larval moult. In E.elutella about seven short photoperiods were required for larvae to enter diapause. In P.interpunctella high population density during larval development increased the proportion of larvae entering diapause.

The conditions inducing diapause in laboratory stocks, and in stocks collected from the field, were different. Laboratory stocks of both species did not enter diapause at 25d̀C and required short photoperiods for diapause at 20d̀C. Some larvae of the field stock of E.elutella entered diapause in constant darkness at 30d̀C, the number being increased at low R.H., and almost all did in short photoperiods at 25°C. At 20T, most larvae of this stock entered diapause regardless of photoperiod, and at 15°C all did. In P.interpunctella up to one‐third of larvae of the field stock entered diapause in short photoperiods at 25d̀C, and all did if transferred to short photoperiods at 20d̀C.

In unheated premises, falling temperatures normally induce diapause in E.elutella each autumn, photoperiod only being important if temperatures are high. In P.interpunctella, photoperiod is a more important factor because it can override the effect of falling temperature to a greater extent than in E.elutella. In both species, however, different field populations may respond in different ways.
Factors influencing the duration and termination of diapause in the Warehouse moth, Ephestia elutella
Authors: BELL C. H.
Published: March 2008

The influence of environmental factors on the duration of diapause was evaluated in larvae of Ephestia elutella (Hübner) reared in short photo‐periods at 25d̀C or below. Termination of diapause was hastened by long photoperiods, high temperatures, long periods at low temperature, or exposure to fumigants. Diapause terminated rapidly under long photoperiods at 30 or 25d̀C, but not at 20d̀C. The critical photoperiod for the termination of diapause was similar to that for induction, lying between 13 and 16 h at 25d̀C. The longest duration of diapause occurred in constant darkness (DD) at 20d̀C. However, batches of larvae reared at 20d̀C in DD pupated a little sooner than batches reared under LD, if both were transferred at the start of diapause to warm, long‐day conditions. Long exposure to low temperature reduced the number of long photoperiods necessary for the rapid termination of diapause at high temperature. Samples of larvae brought to the laboratory at monthly intervals from an unheated outbuilding in which they were overwintering, required an average of c. 200 days to pupate in DD at 25d̀C when transferred in December, compared with only 32 days when transferred in February or March. By comparison, batches transferred to LD 16:8 at 25d̀C required 39 days when transferred in December and 20–24 days in February and March. Holding at low temperature for long periods also encouraged synchronous emergence of the sexes. Duration of diapause was generally shorter in a laboratory stock than in a stock collected from the field.
Grooming and pollen manipulation in bees (Apoidea): the nature and evolution of movements involving the foreleg
Authors: JANDER RUDOLF
Published: March 2008

Three modes of self cleaning occur in insects: nibbling by the maxillae, scraping one structure by another in one direction only, and rubbing back and forth while the respective parts are in continuous contact. This paper describes a comprehensive and comparative account of this behaviour in bees, with special reference to the cleaning of or by the forelegs.

Bees, like all Hymenoptera, clean various parts of the head, including the mouthparts and the antennae, with the forelegs. Lower Hymenoptera scrape each antenna with either foreleg; in the species of Aculeata that possess the antenna cleaner (strigil) on the foreleg, only the ipsilateral leg is used. The thoracic dorsum of most bees, as in many sphecoid wasps, is scraped in a forward direction by the middle leg;Triepeolusspp., however, use the hind leg, and the Anthophorinae the foreleg.

Some beetles and lacewings clean their forelegs in the mouthparts by nibbling and scraping. Most higher Hymenoptera as a rule scrape the foreleg between the ipsilateral maxilla and the labium; bees, however, clamp the foreleg between the flexed ipsilateral middle leg and then scrape it. An evolution of this behaviour is postulated via several intermediate forms derived from original stepping movements.

Halictidae and Andrenidae clamp the foreleg for scraping underneath the middle tibia, whereas all other bees nearly always clamp it underneath the middle basitarsus. Very similar movements are used in various species for transferring pollen, oil, or nest materials from the foreleg to the middle leg.

It is argued that the original way of pollen carrying in bees must have been by filling the crop through direct eating or by scraping pollen off the foreleg between the ipsilateral maxilla and the labium. The latter movement is widespread among bees and is homologous to the normal foreleg cleaning in the mouthparts of most other Hymenoptera. The efficiency of this behaviour is enhanced in many lower bees by a comb on the galea, which is the homologue of a similar structure widespread among aculeate wasps. In higher bees, Apidae and Anthophoridae, the galeal comb is replaced by an equifunctional stipes comb. Many bees have neither of these types of maxillary combs.
The dynamics of ovarian maturation and oocyte resorption in the Queensland fruit fly, Dacus tryoni, in daily‐rhythmic and constant temperature regimes
Authors: MEATS A. , KHOO K. C.
Published: March 2008

The rate of oocyte development in constant regimes corresponded to the rates predicted by Pritchard's (1970) relationship which indicates that the lower temperature threshold is 13.5dgC. Rates in fluctuating regimes indicated that development occurs at certain temperatures below the constant threshold if these are alternated with higher temperatures on a daily basis

In certain fluctuating regimes, oocyte development occurred at a rate in excess of 3.5% per day and maturation proceeded to completion. In such regimes resorption occurred only if egg laying was prevented; when this happened the terminal oocytes usually remained intact and the penultimate ones were resorbed. In other fluctuating regimes, oocyte development proceeded at a rate of less than 3.5% per day and no maturation was achieved because the most advanced oocytes were resorbed‐either before or during the vitellogenic phase.

The 3.5% threshold corresponds to a value of 2 day‐degrees per day (2DDPD) above 13.5d̀C. Resorption, but no development, was observed in partly mature flies around O DDPD, whereas neither occurred in a still colder regime. These results are shown to be in accord with Fletcher's (1975) field data which are also used to discuss the significance of resorption. Finally, the DDPD relationship is used to define those daily temperature profiles which may permit maturation in the field.
Effects of leaf age on feeding ‘preference’ and egg laying in the chrysomelid beetle, HaZtica lythri
Authors: PHILLIPS W. M.
Published: March 2008

Final instar larvae and adults of the chrysomelid beetle Haltica lythri Aubé were tested for their feeding preferences on young and senescent leaves of their host plant Epilobium hirsutumL., and found to spend most of the time feeding on young leaves when in a free‐choice situation. Females fed senescent leaves laid significantly fewer eggs than females fed young leaves. Feeding on senescent leaves is discussed in an ecological context.
Reduction in responsiveness of male apple moths, Epiphyas postvittana, to sex pheromone following pulsed pheromonal exposure
Authors: BARTELL R. J. , LAWRENCE L. A.
Published: March 2008

ABSTRACT. The degree of reduction in sex pheromone‐mediated responsiveness of male light‐brown apple moth, which results from previous exposure to the pheromone, is increased by presenting the pre‐exposure dose as a sequence of short pulses, rather than as a single pre‐exposure. This effect is interpreted in terms of adaptation and disadaptation of the pheromone receptors, and of central habituation and dishabituation. When the interval between pulses is of sufficient length for receptor disadaptation, the total amount of excitatory input generated by the pulsed pheromone would be greater than if the same dose were to be applied continuously. It is concluded that the greater resultant reduction in responsiveness following pulsing is directly related to the greater degree of habituation resulting from this presumed increased amount of excitatory input.
Sound production in some triatomine bugs
Authors: SCHOFIELD C. J.
Published: March 2008

ABSTRACT. Adults of five species of Triatominae were found to stridulate when handled: Triatoma protracta, T. lenti, T. infestans, Panstrongylus megistus and Dipetalogaster maximus. All five larval stages of D. maximus were also found to stridulate. Stridulation is caused by the tip of the reflexed proboscis rubbing along the transversely ridged prosternal groove. Each syllable of the resulting song is produced by a single antero‐posterior movement of the proboscis and contains 80–150 intrasyllabic spikes, each corresponding to the striking of a single ridge in the prosternal groove. Analysis of tape recordings of the songs showed that all species have a broad frequency band without well‐defined maxima, extending into the ultrasonic with frequencies of up to 50–100 kHz. The lowest frequency produced by each species is consistent with the repetition rate of the striking of prosternal ridges by the proboscis. No behavioural response to the replayed song was detected, but when the song was replayed to female P. megistus the frequency of action potentials within the antennal nerve correlated well with the intrasyllabic spike frequency of the replayed song. Possible microphonic artefacts were not, however, excluded. Possible functions of the song are discussed.
Daily changes in the sensitivity of wax‐moth larvae, Galleria mellonella, to cooling stress
Authors: BOGUŚ MIECZYSŁWA J. , CYMBOROWSKI BRONISŁAW
Published: March 2008

ABSTRACT. Sensitivity to cooling stress in the last instar larvae of Galleria mellonella was measured as (a) the number of extra larval moults, (b) the number of larvae retaining the ability to secrete silk, and (c) the number showing arrested development. With respect to (a) and (b) there were considerable differences in sensitivity across the day. A relationship was observed between the number of additional larval moults induced by chilling and the ability of prepupal larvae to spin silk: the periods during the 24 h when the most larvae passed through additional larval moults were periods characterized by the smallest number of larvae capable of spinning, and vice versa. These daily changes were apparently partly independent of developmental age. Daily variations in sensitivity also occurred when larvae of the same age were cooled at different times of day. It is suggested that these rhythms in cold‐sensitivity are related to a cold‐sensitive rhythm in juvenile hormone secretion, or hormone sensitivity in the tissues.
Neural and hormonal control of pheromone biosynthesis in the bark beetle, Ips paraconfusus
Authors: HUGHES P. R. , RENWICK J. A. A.
Published: March 2008

ABSTRACT. Synthetic juvenile hormone (JH) induced the synthesis of the three pheromones, ipsenol, ipsdienol and 2‐phenylethanol, by Ips paraconfusus males and enhanced the conversion of (–)‐α‐pinene to a fourth pheromome, cis‐verbenol. Synthetic JH also mimicked the stimulatory effect of feeding on the metabolism of myrcene to ipsdienol and ipsenol. Implantations of corpora allata and/or corpora cardiaca from fed or newly‐emerged males into intact or decapitated males were performed. The results indicated that JH acts indirectly by stimulating the release of brain hormone, and the release of JH in unfed males is prevented by neural inhibition which is removed by the stretching of the gut during normal feeding. Failure of any hormonal treatment or gland implantation to stimulate cis‐verbenol synthesis in the absence of exogenous α‐pinene is presented as evidence that no endogenous precursor for this pheromone is present. An apparent seasonal variation in the ability of males to produce ipsdienol and ipsenol when treated with JH was observed.
The hyperglycaemic activity of locust adipokinetic hormone
Authors: JONES JENNIFER , STONE JUDITH V. , MORDUE W.
Published: March 2008

ABSTRACT. Pure adipokinetic hormone (AKH) extracted from the glandular lobes of locusts induces hyperglycaemia in cockroaches. Larger doses (20–200 pmol) of AKH are required to induce hyperglycaemia in the cockroach than are required to produce hyperlipaemia in locusts (1–20 pmol).
Oriented responses of carrot fly larvae, Psila rosae, to plant odours, carbon dioxide and carrot root volatiles
Authors: JONES O. T. , COAKER T. H.
Published: March 2008

ABSTRACT. The responses of carrot fly larvae, Psila rosae, to host plant volatiles were studied. Two criteria for an oriented response were used: one based on whether an individual reached within 1.5 cm of the odour source and one involving analysis of the track patterns of larvae within 3 cm of the odour source. All larval instars were attracted to both host and non‐host plant material, though to a lesser degree by the latter; they were also attracted to CO2, but not to N2. A steam volatile fraction of carrot roots, and methyl eugenol, a volatile component of this fraction, also attracted the larvae, differentially at different concentrations. The possible roles of both CO2 and the host‐specific secondary plant volatiles in the host plant finding behaviour of soil inhabiting arthropods are discussed.
Photoperiod and temperature modulation of male eclosion timing in the white peach scale, Pseudaulacaspis pentagona
Authors: McLAUGHLIN J. R. , ASHLEY T. R.
Published: March 2008

ABSTRACT. The daily rhythm of eclosion of male Pseudaulacaspis pentagona is entrained by the interaction of the prevailing light and temperature cycles. The onset of light is the critical cue for the release of eclosion. Darkness or increasing temperature inhibits it. A decrease in temperature induces eclosion during the photophase, but does not do so during the scotophase. The eclosion rhythm is modified daily by the prevailing temperature cycle, apparently to ensure maximum survival of, and mating by the short‐lived males.
The effects of increasing mandibular load on electrical activity in the mandibular closer muscles during feeding in the desert locust, Schistocerca gregaria
Authors: SEATH IAN
Published: March 2008

ABSTRACT. Electrical activity from individual mandibular closer muscle fibres of the desert locust Schistocerca gregaria was monitored during three feeding conditions: chewing soft grass, chewing soft grass against an artificial load, and chewing an incompressible grass. Spiking frequency during bursts of activity was found to increase under conditions of increased artificial, and natural load. These increases in spiking frequency occurred over a frequency range much lower than that necessary to produce a maximal tetanic contraction, and therefore correspond to increases in power output by the closer muscles in response to increases in load. A possible mechanism for this is described.
A continuously recording respirometer, used to measure oxygen consumption and estimate locomotor activity in tsetse flies, Glossina morsitans
Authors: TAYLOR PAUL
Published: March 2008

ABSTRACT. The construction of a continuously recording respirometer is described. The oxygen consumption patterns of male tsetse flies recorded with this apparatus generally match their patterns of locomotor activity previously reported from actograph data and direct observation. Clear signs of a diel rhythm, in a light cycle, were still apparent at the low temperature of 15°C.
Studies on the mid‐gut of the desert locust,Schistocerca gregaria.
Authors: ANDERSON M. , COCHRANE D. G.
Published: March 2008

ABSTRACT.The gross morphology of the mid‐gut musculature of the desert locust,Schistocerca gregariais described. Some of the electrophysiological characteristics of the external longitudinal muscle fibres were examined. The membrane potentials have mean values of ‐24.7mV (SE ± 7.3). Spontaneous post‐synaptic potentials were recorded, and the responses of the muscle fibres to electrical stimulation of their nerve supply studied.
Some relationships between the ‘calling’ posture and sexual receptivity in unmated females of the moth, Ephestia cautella
Authors: BARRER P. M. , HILL R. J.
Published: March 2008

ABSTRACT. A positive relationship is shown between the frequency of successful completions of courtship and the extent of development of the ‘calling’ posture of E. cautella females. Further relationships are shown between the frequency of successful completions of courtship and the positions in which calling females hold their antennae. During late photophase, calling females which hold their antennae forward are less likely to mate than are similarly calling females which hold their antennae back over the wings, whereas in early scotophase this relationship is reversed, and calling females which hold their antennae forward are more likely to mate than are similarly calling females which hold their antennae back. These observations are discussed in relation to the diel rhythm of the species, disturbance, and female receptivity to male courtship.
A new method for cutting the mouth‐parts of feeding aphids, and for collecting plant sap
Authors: DOWNING N. , UNWIN D. M.
Published: March 2008

ABSTRACT. A technique is described for cutting the mouth‐parts of feeding aphids with a radio frequency probe, and for collecting plant sap from the severed ends of the stylets without contamination. The technique is a significant improvement on previous methods used, and will allow reliable quantitative analysis to be made of plant sap on which the aphids feed.
Hormonal and host factors stimulating pheromone synthesis in female western pine beetles, Dendroctonus brevicomis
Authors: HUGHES P. R. , RENWICK J. A. A.
Published: March 2008

ABSTRACT. Newly‐emerged, unfed Dendroctonus brevicomis females produced large quantities of the pheromone exo‐brevicomin when treated topically with the synthetic juvenile hormone 10,11‐epoxyfarnesenic acid methyl ester (JH III). No exogenous source of pheromone precursor was required, and decapitation experiments showed that the synthetic JH was effective in the apparent absence of brain hormone. However, implantations of combined corpora allata—corpora cardiaca from either newly‐emerged or fed (i.e. pheromone producing) females failed to stimulate exo‐brevicomin synthesis by recipient unfed beetles. Biosynthesis of exo‐brevicomin was induced in newly‐emerged females by ingestion of host phloem, and the stimulatory phloem component was found in methanol extracts. Neither less polar solvent extracts of phloem nor artificial distension of the gut with air was effective in stimulating pheromone synthesis.
Some effects of amputation of the antennae on pigmentation, growth and development in the locust, Schistocerca gregaria
Authors: MORDUE(LUNTZ) A. J.
Published: March 2008

ABSTRACT. Removal of the antennae from Schistocerca gregaria early in the third or fourth instar resulted in fifth instar nymphs with a green haemolymph and cuticle. Antennectomized adults had a lower somatic dry weight and a smaller fat body than operated control insects. In addition, their rate of sexual development increased and some of their morphometric parameters were altered. Implantation of corpora allata into fourth instar nymphs induced a green coloration of the haemolymph after a few days. It is suggested that antennectomy of Schistocerca nymphs resulted in an increased effectiveness of the corpus allatum hormone with its concomitant effects on nymphal pigmentation, growth and development, and adult morphometries. It is further suggested that antennectomy of crowded locusts may mimic, for them, the uncrowded condition, by reducing sensory input.
The action of tetrodotoxin on the cockroach, Periplaneta americana: a toxicological and neurophysiological study
Authors: GAMMON DEREK W.
Published: March 2008

ABSTRACT. Some sublethal effects of tetrodotoxin (TTX) on the cockroach were investigated using chronically implanted extracellular electrodes. Prostration and subsequent paralysis were correlated with blockage of peripheral nerves, the CNS being apparently unaffected at the dose employed. Over several days following treatment many cockroaches showed a reversal of the symptoms and finally recovered fully. This coincided with recovery of the blocked nerves. It is suggested that TTX can be used to distinguish pharmacologically the peripheral and central actions of drugs and insecticides. Furthermore, TTX treatment could also be useful in the analysis of the subcellular nature of the sodium channels in nerve membrane.
The transport of the cardiac glycoside ouabain by the Malpighian tubules of Zonocerus variegatus
Authors: RAFAELI‐BERNSTEIN ADA , MORDUE W.
Published: March 2008

ABSTRACT. Isolated Malpighian tubules of Zonocerus variegatus excreted cardiac glycosides more efficiently than isolated tubule preparations from Locusta migratoria. A higher rate of excretion of ouabain by isolated tubules was induced in adult Zonocerus given this toxin in their diet.
A versatile high frequency radio microcautery
Authors: UNWIN D. M.
Published: March 2008

ABSTRACT. The paper describes a radio frequency microcautery operating at 27 MHz. Unusually high power is used to achieve a high rate of temperature rise in the tissue in order to leave fluid transporting vessels unblocked, e.g. aphid stylets. The power is adjustable down to levels appropriate to normal radio cautery applications and a timer is provided for single pulse operation. A special‐purpose thermionic valve is used to generate the power which is fed to a remote probe.
Response characteristics and after effects of multimodal neurons in the mushroom body area of the honey bee
Authors: ERBER J.
Published: March 2008

ABSTRACT. Single cell recordings in the mushroom body area of the bee revealed that the majority of cells responds to more than one modality. Five different modalities were tested: light, scent, sugar‐water applied to the antennae or the proboscis, and mechanical stimuli of the antennae (air puffs). The background discharge (spontaneous) frequency of the neurons was correlated with the recording site, being low in the calyx area and high in the area of the β‐lobes. No correlation between the reaction spectra of neurons and the recording location was found. A simple classification of single cells into different classes is not possible. Some units change their response pattern during recording; this is interpreted as an indication of other inputs which were not controllable in the experiments. After‐effects, lasting some seconds to minutes, were found with scent, light and sugar‐water stimuli. The olfactory and gustatory inputs obviously play an important role in activating multimodal units. Some neurons showed increasing sensitivity for a scent after a number of olfactory conditionings. An increase of sensitivity in these units is correlated with an increase of the spontaneous discharge frequency.
Food discrimination and induction of preference for artificial diets in the tobacco hornworm, Manduca sexta
Authors: STÄDLER ERICH , HANSON FRANK E.
Published: March 2008

ABSTRACT. Feeding discrimination of Manduca larvae reared on leaves and a variety of artificial media was tested against leaves, various media, solvent fractions of leaves and media, and media components, including pure chemicals. Field‐collected animals showed the same preferences as did animals cultured in the laboratory for many generations. Rearing larvae on a leaf species, an artificial diet, or homogenized leaves added to artificial diet induced a preference for that food in subsequent choice tests. Extracts of these foods using organic solvents (particularly hexane) elicited feeding choices resembling those evoked by the foods themselves: water extracts were effective as stimulants or deterrents, but responses to them differed considerably from responses to the foods. Animals raised on a defined artificial diet showed an increased preference (or decreased deterrence) for the lipid component (linolenic acid) of that diet in behavioural tests. Thus induction of preference was shown to be influenced by a specific nutrient compound. Fifteen artificial diets were tested; three were successful, including a completely defined medium. Various components of the diets were tested for feeding preferences, both as omissions from the main diet and as pure compounds. Some were stimulatory, most were neutral or slightly deterrent; a few were strongly deterrent. With the exception of linolenic acid, preferences for pure compounds were not significantly correlated with the food on which the animals were reared. The data suggest that food discrimination depends on the perception of a complex chemical message comprised of both polar and non‐polar compounds, with the latter being of somewhat greater importance. The results are consistent with the explanation of the induction of feeding preferences being due to a reduced responsiveness to deterrents, to an increased preference for feeding stimulants or to both.
Arrestment responses of the parasitoid, Nemeritis canescens, to a contact chemical produced by its host, Plodia interpunctella
Authors: WAAGE JEFFREY K.
Published: March 2008

ABSTRACT. The locomotory response of walking parasitoids to a contact chemical from their host is reviewed, and in particular the response of the ichneumonid, Nemeritis canescens Grav., to the mandibular gland secretion of its host, Plodia interpunctella Hubn., is investigated. In response to the presentation of the host chemical on a surface, a walking Nemeritis exhibits a complex ortho‐kinetic response involving stopping, walking at a reduced speed and probing with the ovipositor. In response to the removal of the chemical following presentation, as would occur when the insect left the edge of the chemical patch, the wasp exhibits a klinotactic response which directs it back to the patch at an average angle of 157° relative to the orientation at the moment of stimulation. This turning‐back response at the patch edge greatly increases the time spent on a patch of contact chemical. The waning of this response determines when a host patch is abandoned. This waning is retarded by increasing the concentration of contact chemical on the patch and by opposition while on the patch.
Topography and electrical activity of peripheral neurons in the abdomen of the tsetse fly (Glossina) in relation to abdominal distension
Authors: ANDERSON M. , FINLAYSON L. H.
Published: March 2008

ABSTRACT. The detailed morphology of the abdominal nervous system of adult male and female Glossina morsitans is described. Staining with methylene blue revealed about twenty peripheral neurons distributed in a relatively constant pattern in each abdominal segment. Suction electrode recordings were made of the electrical activity generated by these neurons. Three pairs per segment present on the ventral body wall responded to mechanical stimulation, and are assumed to play a primary role in monitoring abdominal distension. Also present in each segment is a pair of dorsal longitudinal stretch receptors which require a greater intensity of mechanical stimulation to respond than do the ventral body wall neurons. A proposal as to how the various mechanically responsive receptors are involved in monitoring abdominal distension is presented.
Embryonic diapause in the psocid, Peripsocus quadrifasciatus: photoperiod, temperature, ontogeny and geographic variation
Authors: EERTMOED GARY E.
Published: March 2008

ABSTRACT. Embryonic diapause in Peripsocus quadrifasciatus from temperate North America is a maternally‐induced, facultative, temperature‐dependent response to photoperiod. The length of the critical photoperiod necessary to induce diapause increases approximately 15 min for every degree increase of a population's latitude. Variations in this critical photoperiod cline are probably adaptations to the temperature influences of altitude and other local factors. Nymphs play an important role in reading environmental conditions and determining the adults' response to them. The evidence on cold survival of non‐diapausing embryos suggests dormancy as an alternative to winter diapause, particularly in the more moderate, southern latitudes.
Electrophysiological response of honey bee labial palp contact chemoreceptors to sugars and electrolytes
Authors: WHITEHEAD ARMAND T.
Published: March 2008

ABSTRACT. The sensilla chaetica on segments II, III and IV of honey‐bee labial palps were investigated electrophysiologically. The responses (spikes/s) correlated with the log of the concentrations of sucrose, glucose, fructose, NaCl, KCl and LiCl, but not with CaCl2 or MgCl2, which gave inconsistent responses. The firing rates were higher and thresholds lower to the sugars than to the electrolytes. The sensitivity of the segments fell in the order: III > II > IV for most of the stimulants, which elicited responses in the order: sucrose > glucose = fructose’ KCl > LiCl > NaCl. The sensilla adapted logarithmically with time. No synergism of response was noted when mixed‐sugar solutions were applied, but inhibition of response was seen when glucose–sucrose, fructose–sucrose, and glucose–fructose–sucrose mixtures were applied. None of the sensilla tested responded to water.
Factors conducive to increased protein feeding by the blowfly Phormia regina
Authors: BELZER W. R.
Published: March 2008

ABSTRACT. Each period of elevated protein consumption by Phormia regina was associated with some recognizable physiological event that requires protein synthesis (e.g. tanning, adult fat body development, vitellogenesis). Injecting cycloheximide to inhibit protein synthesis prior to the onset of such events delayed the events and also the development of the associated periods of protein hunger. Injecting cycloheximide after a known period of protein synthesis had occurred, however, did not postpone the normally associated protein hunger even while the inhibitor was fully active. The findings conform to a hypothesis that an unidentified deficit, created by protein synthesis, underlies the tendency by Phormia to increase its ingestion of proteinaceous materials. The effects which different hormones have on protein hunger are evidently indirect results of their control of different periods of protein synthesis.
Recurrent nerve inhibition of protein feeding in the blowfly Phormia regina
Authors: BELZER W. R.
Published: March 2008

ABSTRACT. Stretch receptors located in the foregut appear to contribute negative feedback to the ingestion of protein by Phormia; as fluid is consumed, the concomitant stretch impedes further drinking. This inhibitory feedback, transmitted to the frontal ganglion via the recurrent nerve, seems to depress protein ingestion less than carbohydrate ingestion. Such a disparity may help to ensure that the female fly acquires enough protein for egg development through the retention of her ability to consume available protein even after carbohydrate consumption has been terminated.
X‐ray investigation of gas bubble formation, and water loss in tsetse fly pupae
Authors: LANGLEY P. A. , ELY R.
Published: March 2008

ABSTRACT. Using a microfocal X‐ray apparatus, a gas bubble was detected within the puparium of Glossina morsitans. The bubble appeared between 6 and 15 h after pupariation and was associated with one of the longitudinal tracheal trunks of the third instar larva. The bubble grew and achieved maximum size approximately 96 h after pupariation. It then disappeared at the time of eversion of the pupal appendages. There was a close correlation between bubble size and the weight of water lost since the time of pupariation. At the time of eversion of the pupal appendages the gas bubble apparently passed out through the longitudinal tracheal trunk and posterior spiracle to occupy the space between larval (puparial) and pupal cuticle. It is suggested that the bubble plays a vital role in the separation of these cuticular layers and that to this end water loss from the puparium is essential.