bluuebunny/crossref_metadata_2025 huggingface dataset:
Residue of gutta‐percha and a glass ionomer cement sealer following root canal retreatment
Authors: FRIEDMAN S. , MOSHONOV J. , TROPE M.
Published: September 2010

A previous report indicates that root canals obturated with a new glass ionomer cement endodontic sealer (Ketac‐Endo, Espe, Germany) and laterally condensed gutta‐percha can be retreated by ultrasonic instrumentation. To address the possibility of Ketac‐Endo being used without condensation of gutta‐percha, the purpose of this study was to evaluate the efficacy of ultrasonic retreatment in canals obturated with single‐cone gutta‐percha and Ketac‐Endo. Thirty root canals were prepared in a standardized way to ISO size 40 and obturated with gutta‐percha and Ketac‐Endo. Either a size 40 gutta‐percha cone was used with and without lateral condensation, or a size 25 single cone, without condensation. After 14 days, the canals were retreated using chloroform and ultrasonic instrumentation. The roots were split vertically, and the amount of residual debris on the canal walls was assessed by three examiners using a dissecting microscope. Debris was recorded in the apical, middle and coronal canal levels according to a preset evaluation scale. The mean scores for each group were compared by ANOVA and Mann‐Whitney U‐test, with a 5% level of significance. In the roots obturated with lateral condensation the amount of residual debris in the coronal and middle canal levels was lower than in the other two groups, whereas in the apical level it was higher. Statistically, only the differences in the apical level were significant (P < 0.03). It was concluded that ultrasonic retreatment may be performed effectively in root canals obturated with single‐cone gutta‐percha and Ketac‐Endo.
Cemental tear: a case report
Authors: Stewart M. L. , McClanahan S. B.
Published: September 2010

Aim  To report a case of a cemental tear.

Summary  A case is reported of a patient with a history of trauma, root canal treatment and retreatment procedures to eliminate recurring sinus tracts. An exploratory surgery, extraction, and biopsy resulted in a diagnosis of cemental tear.

Key learning points  • The detachment of a fragment of cementum is described as a cemental tear.

• Cemental tears have been reported in the periodontal literature associated with localized, rapid periodontal breakdown. Common causative factors are aging and traumatic occlusion but the exact aetiology is unknown.

• Trauma may be considered as a potential aetiologic factor for cemental tears in addition to occlusal traumatism and aging.
Ex vivo biocompatibility tests of regular and white forms of mineral trioxide aggregate
Authors: Ribeiro D. A. , Matsumoto M. A. , Duarte M. A. H. , Marques M. E. A. , Salvadori D. M. F.
Published: September 2010

Aim  To examine the genotoxicity and cytotoxicity of regular and white mineral trioxide aggregate (MTA) ex vivo by the single‐cell gel (comet) assay and trypan blue exclusion test, respectively.

Methodology  Aliquots of 1 × 104 Chinese hamster ovary cells were incubated at 37 °C for 3 h with grey and white forms of MTA at final concentrations ranging from 1 to 1000 μg mL−1. The negative control group was treated with vehicle control phosphate buffer solution for 3 h at 37 °C and the positive control group was treated with methyl metasulfonate (at 1 μg mL−1) for 1 h at 37 °C. After incubation, the cells were centrifuged at 180 g for 5 min and washed twice with fresh medium and resuspended with fresh medium. Each individual treatment was repeated three times consecutively to ensure reproducibility. Parameters from single‐cell gel (comet) and cytotoxicity assays were assessed by the Kruskal–Wallis nonparametric test.

Results  Neither compounds produced genotoxic effects with respect to the single‐cell gel (comet) assay in all concentrations evaluated. In the same way, the dose–response relationships of all compounds tested at concentrations ranging from 1 to 1000 μg mL−1 on cell viability assessed by the trypan blue assay displayed no statistically significant differences (P > 0.05) for either endodontic material.

Conclusions  Regular (grey) and white MTA are not genotoxins and do not induce cellular death.
Incidence and antimicrobial susceptibility of Porphyromonas gingivalis isolated from mixed endodontic infections
Authors: Jacinto R. C. , Gomes B. P. F. A. , Shah H. N. , Ferraz C. C. , Zaia A. A. , Souza‐Filho F. J.
Published: September 2010

Aim  To investigate the prevalence of Porphyromonas gingivalis in root canals of infected teeth with periapical abscesses and to investigate the antimicrobial susceptibility of this species to some frequently prescribed antibiotics.

Methodology  Samples were obtained from 70 root canals of abscessed teeth. Microbial sampling, isolation and bacterial identification were accomplished using appropriate culture methods for anaerobic species. The antimicrobial susceptibility of the 20 strains of P. gingivalis isolated was determined by using the E‐test. The antimicrobial agents tested were amoxicillin, amoxicillin + clavulanate, azythromycin, benzylpenicillin, cephaclor, clindamycin, erythromycin, metronidazole and tetracycline.

Results  A total of 352 individual strains, belonging to 69 different species, were isolated. Eighty three percent of the strains were strict anaerobes and 47.5% of the isolated bacteria were Gram‐negative. Porphyromonas gingivalis was found in 20 root canals and was most frequently found in symptomatic cases. Statistically, the presence of P. gingivalis was related to purulent exudates and pain on palpation (both P < 0.05). All P. gingivalis strains were sensitive to amoxicillin, amoxicillin + clavulanate, cephaclor, clindamycin, benzylpenicyllin, metronidazole and tetracycline. The lowest range of minimum inhibitory concentration (MIC) (0.026–0.125 μg mL−1) was observed against amoxicillin + clavulanate and clindamycin. The lowest MIC 90 was observed against clindamycin (0.064 μg mL−1). One strain was resistant to erythromycin and eight strains were resistant to azythromycin.

Conclusion  Porphyromonas gingivalis pathogen is isolated with frequency from root canals of infected teeth with periapical abscesses. Amoxicillin, as well as amoxicillin–clavulanic acid and benzylpenicillin were effective against P. gingivalis.
Female home range size and the evolution of social organization in macropod marsupials
Authors: Fisher Diana O. , Owens Ian P. F.
Published: September 2010

1. Traditional explanations for interspecific variation in home range size are based almost exclusively on analysis of northern hemisphere eutherian mammals. These suggest that variation in body size is the most important factor, while climate and diet are less important. The generality of these explanations is tested using a novel database on macropod marsupials (kangaroos and allies).

2. We found a 490‐fold difference in home range size and a 50‐fold difference in body weight amongst macropods. In agreement with studies on eutherians, female home range size was strongly correlated with body weight.

3. However, unlike the pattern in eutherians, climate was more strongly associated with home range size than was body weight: annual rainfall explained more than half of the variation, while group size (6%) and population density (8%) were minor explanatory variables, and female body weight explained no further variation.

4. When we used a phylogeny‐based comparative method, annual rainfall explained 32% of the variation and body size a further 16%.

5. Sex differences in home range size were not explained by body size dimorphism, but were strongly related to rainfall and less strongly related to the degree of female home range overlap. Species with large sex differences in home range size lived in high‐rainfall habitats where female ranges were small.

6. We suggest that climate has been a key factor in social evolution of macropods. In species inhabiting productive habitats, small female home ranges allow males to overlap with more females by increasing home range size. Males often compete for females by searching widely. In less productive habitats, males cannot further increase or defend their already large home ranges, resulting in similar‐sized ranges in both sexes. Where female home range overlap is high, males need not increase home ranges as much, but this effect is secondary to that of climate.

7. In agreement with the theory that competitive searching by males is not necessarily related to body size, species with extreme size dimorphism had no sex difference in home range size, and species with extreme home range differences between the sexes showed no particular pattern of dimorphism.

8. Variation among macropod species in home range size and social organization is more closely correlated with variation in habitat productivity, and is less related to body size, diet, density and group size, than predicted by eutherian‐based explanations.
Effects of food limitation and emigration on self‐thinning in experimental minnow cohorts
Authors: Dunham J. B. , Dickerson B. R. , Beever E. , Duncan R. D. , Vinyard G. L.
Published: September 2010

1. The theory of food‐regulated self‐thinning (FST) for mobile animals predicts population density (N) to be an inverse function of mean body mass (W) scaled to an exponent (b), such that N = k W−b, where k is a constant. FST also predicts energy requirements (or energy flow) to remain constant over time (termed energetic equivalence) as losses to cohorts (e.g. emigration and mortality) are balanced by increased growth of surviving individuals.

2. To test these predictions, we analysed the dynamics of six experimental minnow cohorts. Replicate populations of fish were held under identical conditions with a constant and limited supply of food over a 126‐day period. Half of the cohorts were open to emigration, and half were closed so that fish could only be lost through starvation mortality.

3. Patterns of self‐thinning indicated non‐linear changes in population density and energy flow in relation to changes in mean body mass and time, respectively. Non‐linear patterns of self‐thinning were probably due to a delayed growth response to changes in population density effected through mortality and/or emigration. Contrary to results of similar experiments on other fish, emigration did not have a significant influence on the pattern of self‐thinning.

4. These results may be attributed to trophic interactions within cohorts and the importance of social behaviour to cohort dynamics. Both population density and energy flow in our experimental populations appeared to cycle, with episodes of starvation and mortality alternating with food recovery and weight gain, as predicted by recent models of stepwise die‐off and stunted growth in animal cohorts.

5. Most of the support for FST in mobile animals comes from observational data on mean body mass and population density. Potentially important mechanisms, including the manner in which individuals are lost or retained in populations, are usually not investigated directly. Such tests of FST can only provide equivocal support. Detailed observational study and controlled experiments are needed to understand casual mechanisms.
Relationships between sex ratio, climate and density in red deer: the importance of spatial scale
Authors: Mysterud Atle , Yoccoz Nigel G. , Stenseth Nils CHR. , Langvatn Rolf
Published: September 2010

1. Recently, contrasting evidence of density‐dependent offspring sex ratio variation in red deer (Cervus elaphusL.) has been presented.Kruuket al. (1999)reported that the proportion of male red deer born on the island of Rum, Scotland, each year declined with increasing population density and with winter rainfall, i.e. as nutritional stress in females increased. In contrast,Postet al. (1999a)reported increasing male‐biased offspring sex ratios in Hordaland, Norway, with both rising numbers of hinds and increasing values of the North Atlantic Oscillation (NAO), which they regarded an index of severe winters.

2. Compared toPostet al. (1999a), we reanalysed sex ratio variation on a greatly extended data set, including four populations of Norwegian red deer, taking into account a finer population substructure.

3. The proportion of male calves shot each autumn declined markedly as density increased in all four populations. The proportion of male calves shot each autumn increased significantly with an increasing NAO index in one of the four populations, but there was no residual effect of the NAO once the effect of snow depth (at low elevation) was controlled for (decreasingly male biased harvest with increasing snow depth).

4. At the west coast of Norway, the NAO is positively correlated with temperature and precipitation. However, since temperatures in this region often are around 0 °C during winter, the relationship between the NAO and snow depth may be difficult to predict.

5. An analysis of variation in snow depth revealed that snow depth was negatively correlated with the NAO at low altitudes (below 400 m), but this relationship was reversed at high altitudes giving a positive correlation between snow depth and the NAO. We therefore suggest that a high NAO index indicates favourable winter conditions for red deer, as red deer winter at low altitude, and since recent studies show that a high index of the NAO is generally positively correlated with body weight in red deer.

6. Female red deer thus reared fewer sons as nutritional stress increased with increasing density and severity of climate in Norway, which is consistent with the birth sex ratios observed on Rum, Scotland.
Mouse population eruptions in New Zealand forests: the role of population density and seedfall
Authors: Choquenot David , Ruscoe Wendy A.
Published: September 2010

1. Sporadically eruptive house mouse populations provide an opportunity to test ideas about how intrinsic and extrinsic factors interact to limit rodent populations. New Zealand house mouse populations inhabiting beech forests and associated mosaics erupt when autumn beech seedfall is high. We analysed 25 years of data on mouse density and beech seedfall from a beech and podocarp/hardwood forest mosaic in New Zealand to test the effects of mouse density, beech seedfall and rat density on rates of change in mouse abundance, estimated as the rate of change in a density index for sequential seasonal transitions (r).

2. For autumn to winter and winter to spring transitions, r was related to the magnitude of autumn seedfall and mouse density at the start of each transition, regardless of whether forest types were considered separately or together. For spring to summer and summer to autumn transitions, r was related to mouse density alone. Density dependence could reflect the influence of intrinsic social factors, intraspecific competition for food, or the effects of parasites, diseases or predators.

3. We modified a conceptual model of variation in rodent reproductive effort to derive a general model of how numerical responses to density‐independent increases in food availability, modified by density‐dependent mechanisms and extrinsic precursors to population increase, drive sporadic eruptions in the density of some rodent populations. For house mice in New Zealand, the numerical response to seedfall was modified by some unidentified density‐dependent mechanism(s) to generate sporadic eruptions. Extrinsic precursors to population increase appear to be important in other eruptive house mouse populations.

4. House mouse density in beech forest was more volatile than in podocarp/hardwood forest, maximum rates of increase and decrease being higher in the former. Density tended to be higher in podocarp/hardwood forest when overall density was low, and higher in beech forest when overall density was high. This suggests that between eruptions, mice persist in podocarp/hardwood forest at higher densities than in adjoining beech forest.
Butterfly numbers and weather: predicting historical trends in abundance and the future effects of climate change
Authors: Roy D. B. , Rothery P. , Moss D. , Pollard E. , Thomas J. A.
Published: September 2010

The effect of weather on the size of British butterfly populations was studied using national weather records and the Butterfly Monitoring Scheme (BMS), a national database that has measured butterfly abundance since 1976.

 Strong associations between weather and population fluctuations and trends were found in 28 of 31 species studied. The main positive associations were with warm summer (especially June) temperature during the current and previous year, low rainfall in the current year and high rainfall in the previous year. Most bivoltine species benefited from warm June weather in the current year, three spring species and two that overwinter as adults benefited from warm weather in the previous summer, and most species with moist or semi‐shaded habitats increased following high rainfall and cooler weather in the previous year.

 Simple models incorporating weather variables and density effects were constructed for each species using the first 15 years’ population data (1976–90). These fitted the observed data for that period well (median R2 = 70%). Models were less good at predicting changes in abundance over the next 7 years (1991–97), although significant predictive success was obtained.

 Parameter values of models were then adjusted to incorporate the full 22‐year data‐run. For the eight species whose models had best predicted population changes or fitted the data well (R2 > 85%), models were run from 1767 to 1997, using historical weather records, to ‘predict’ trends in abundance over the past two centuries. For three species it was possible to compare predicted past trends with contemporary accounts of abundance since 1800. In each case, the match between predictions and these qualitative assessments was good.

 Models were also used to predict future changes in abundance, using three published scenarios for climate change. Most, but not all, species are predicted to increase in the UK under warmer climates, a few species stayed stable, and only one species – the agricultural pest Pieris brassicae (Cabbage White) – is predicted to decline.
Habitat heterogeneity affects population growth in goshawkAccipiter gentilis
Authors: Krüger Oliver , Lindström Jan
Published: September 2010

The concept of site‐dependent population regulation combines the ideas of Ideal Free Distribution‐type of habitat settlement and density dependence in a vital rate mediated by habitat heterogeneity. The latter is also known as habitat heterogeneity hypothesis. Site‐dependent population regulation hypothesis predicts that increasing population density should lead to inhabitation of increasingly poor territories and decreasing per capita population growth rate. An alternative mechanism for population regulation in a territorial breeding system is interference competition. However, this would be expected to cause a more even decrease in individual success with increasing density than site‐dependent regulation.

We tested these ideas using long‐term (1975–99) population data from a goshawkAccipiter gentilispopulation in Eastern Westphalia, Germany.

Goshawk territory occupancy patterns and reproduction parameters support predictions of site‐dependent population regulation: territories that were occupied more often and earlier had a higher mean brood size. Fecundity did not decrease with increasing density in best territories.

Using time‐series modelling, we also showed that the most parsimonious model explaining per capita population growth rate included annual mean habitat quality, weather during the chick rearing and autumn period and density as variables. This model explained 63% of the variation in per capita growth rate. The need for including habitat quality in the time‐series model provides further support for the idea of site‐dependent population regulation in goshawk.
Host‐handling behaviours in parasitoids of the black scale: a case for ant‐mediated evolution
Authors: Marco S. Barzman , Kent M. Daane
Published: September 2010

We hypothesize that differences in host‐handling times among three closely related encyrtid parasitoids (Metaphycus anneckei Guerrieri & Noyes, Metaphycus hageni Daane & Caltagirone and Metaphycus lounsburyi[Howard]) are influenced by the defences of their host, black scale (Saissetia oleae[Olivier]). Two forms of host defence were examined: (i) the scale’s possession of a hard integument, and (ii) the effect of ants tending S. oleae.

 Duration of host assessment, host rejection, drilling/oviposition and the presence or absence of host feeding were measured for M. anneckei, M. hageni and M. lounsburyi. Results show that M. anneckei oviposits through the soft ventral integument while M. hageni and M. lounsburyi oviposit through the harder dorsal integument. M. anneckei was never observed to host feed while both M. hageni and M. lounsburyi use hosts for either oviposition or host feeding. The ventral drilling location and absence of non‐concurrent host feeding significantly reduced the overall host‐handling time of M. anneckei, relative to M. lounsburyi and M. hageni.

 Oviposition success of M. anneckei and M. hageni in the presence of ants was compared. An observation arena was established with the numbers of Argentine ants, Linepithema humile (Mayr) and S. oleae manipulated on potted oleanders. M. hageni and M. anneckei were placed, individually, onto the observation arena and their interaction with ants and S. oleae recorded. While 55·3% of M. anneckei successfully oviposited, M. hageni was unable to oviposit or host feed in the presence of foraging ants.

 Field tests were conducted using potted oleander plants, infested with S. oleae, to determine the effect of L. humile on scale density, parasitism levels and parasitoid species composition. Ant‐tended plants had significantly more scale, lower scale parasitism and lower levels of host feeding (as indicated by unknown scale mortality levels). There were also significant differences in parasitoid species composition between ant‐tended and ant‐excluded treatments, with the relative frequency of parasitoid species with faster host‐handling times more common in the ant‐tended treatment.
Absolute foraging rate and susceptibility to interference competition in blackbirds varies with patch conditions
Authors: Cresswell Will , Smith Rik D. , Ruxton Graeme D.
Published: September 2010

Individual variation in feeding rate in the absence of competitors (absolute feeding rate) and change in feeding rate in the presence of competitors (susceptibility to interference) are crucial parameters used in individual‐based population models that predict the distribution of animals across patches. There are, however, few data on how these parameters are dependent on local foraging conditions, which will vary widely in natural systems.

 We tested the hypotheses that absolute feeding rate and change in feeding rate with group size were independent of patch conditions. We observed 27 European blackbirdsTurdus merulafeeding in seminatural experimental patches that were either open (where prey was easily visible) or covered with leaves (where prey was invisible until the leaves had been moved aside by the bird). Absolute feeding rate and susceptibility to interference were measured by recording feeding rates of blackbirds alone and in the presence of increasing numbers of competitors, respectively.

 There was significant individual variation in absolute feeding rate dependent on patch type, with some birds showing relatively large increases in open patches. There was no significant correlation between absolute feeding rate in open and leaf patches.

 There was significant variation in individual susceptibility to interference dependent on patch type. There was no correlation between an individual’s susceptibility to interference in open and leaf patches.

 Mathematical models that seek to make predictions of the distribution of animals across heterogeneous patches should incorporate measures of competitive ability over a wide range of patch conditions, or use more complex parameters that incorporate individual changes in density dependent pay‐offs dependent on patch conditions.
Queuing for preferred territories: delayed dispersal of Siberian jays
Authors: Ekman Jan , Eggers SÖnke , Griesser Michael , Tegelström HÅkan
Published: September 2010

Siberian jays (Perisoreus infaustus) can acquire breeding status along two routes. Some offspring dispersed in their first summer of life, but one‐third of birds ringed as nestlings (39 of 117; 40 broods) postponed dispersal beyond their first winter and up to 3 years of age.

 Birds dispersing in their first summer were able to settle in flocks outside their natal territory, while retained offspring appeared to be queuing for territorial vacancies in high‐quality habitat rather than claiming one of the currently available vacancies of low quality.

 Males dispersing in their first year acquired territories close to human settlements, and with few low spruces. Reproductive success was low in those territories. Males with delayed dispersal acquired territories further away from human settlements and with a high density of low spruces (< 15 m). Reproductive success was high in such territories.

 A preference of all birds for territories characterized by high reproductive success, regardless of their timing of dispersal, suggests a causal relationship to habitat characteristics. A non‐breeding surplus of retained offspring had priority to vacancies at high densities and these birds claimed territories where reproductive success was high. At low densities and without a non‐breeding surplus it was possible for birds dispersing as yearlings to shift territory, and acquire vacant sites of higher quality. It was birds settled in the territories with lowest reproductive success which shifted, and at low population density their territories remained vacant.

 Siberian jays postponed dispersal as a strategic trade‐off, where they forego dispersal options of low quality while queuing for high‐quality habitat. However, a nepotistic parental behaviour towards retained offspring implies that fitness gains of delayed dispersal is not only a question of habitat quality.
Invasion and dynamics of covert infection strategies in structured insect–pathogen populations
Authors: BONSALL M. B. , SAIT S. M. , HAILS R. S.
Published: September 2010

Pathogens are known to cause horizontally transmitted overt (fully symptomatic) and vertically transmitted covert (asymptomatic) infections. Here, we explore a range of different covert infection strategies on the persistence and dynamics of insect host–pathogen interactions.

The three strategies we explore are (i) sublethal infections in which hosts survive initial infection but suffer costs on fecundity or development, (ii) persistent infections, which are transmitted vertically with minimal costs on fecundity and development and which also confer immunity against superinfection and (iii) persistent infections without immunity against superinfection.

We examine the conditions that allow these three strategies to invade. We find that sublethal infections can act to modulate the population dynamics (i.e. cause changes in amplitude and periodicity of cycles) as well as inducing different dynamics (stable and unstable states). This is in line with empirical findings.

Covert infection strategies are also able to generate novel dynamics. In particular, over a wide range of parameter space the predicted dynamics of the covert infections without immunity are of a persistent stable interaction solely between the covertly infected hosts and the pathogen, with the exclusion of clean susceptible hosts.

Our results suggest that, in general, host–pathogen interactions may be maintained in low‐level persistent endemic states without the propensity to show the cyclic oscillations characteristic of enemy–victim interactions. Understanding host–pathogen dynamics requires a knowledge of the factors involved, such as covert infections, that may compensate for the destabilizing effects of time‐lags.
The effect of bovine tuberculosis and brucellosis on reproduction and survival of wood bison in Wood Buffalo National Park
Authors: JOLY DAMIEN O. , MESSIER FRANÇOIS
Published: September 2010

Wood bison (Bison bison athabascaeL.) abundance in Wood Buffalo National Park, Canada, declined from an excess of 10 000 bison in the late 1960s to a low of 2200 bison in the late 1990s.

Bovine tuberculosis (Mycobacterium bovis) and brucellosis (Brucella abortus), were introduced to Wood Buffalo National Park in the late 1920s. As each of these pathogens has the potential to reduce survival and reproduction in bison, they are suspected to have played a role in the decline in bison abundance.

We live‐captured bison in the winters of 1997–2000, tested for tuberculosis, brucellosis and pregnancy and released animals with radio transmitters to evaluate survival.

We found that bison that were positive for both diseases were less likely to be pregnant or to survive the winter than bison positive for one or neither disease. Further, in one population, bison that were tuberculosis‐positive had a substantially lower pregnancy probability.

Demonstrating a negative effect of diseases on survival and reproduction is a necessary, but not sufficient, test of the role of diseases in bison population decline.
Liver involvement in post‐smolt Atlantic salmon, Salmo salar L., infected with infectious pancreatic necrosis virus (IPNV): a retrospective histopathological study
Authors: Noguera P A , Bruno D W
Published: September 2010

Histological changes associated with infectious pancreatic necrosis virus (IPNV) infection have historically been described for the pancreas and gut, but any involvement of the liver was poorly acknowledged or described. The aims of this study were to find robust evidence that the reported increase in liver pathology in Atlantic salmon post‐smolts in natural outbreaks was effectively related to IPNV infection and retrospectively to report when such a shift in the involvement of the liver had taken place, supported by a histopathological description for a differential diagnosis. The study reports new findings concerning the dynamics of liver pathology development, with apoptosis, demonstrated by histological and immunological techniques, described as the most relevant and particular feature. Immunohistochemical examination of affected liver suggests apoptosis is not only the result of the virus infection itself but triggered through the action of the host’s innate immune response. Liver involvement contributes to the nature of infection and becomes an important factor in the disease process. Additionally, it was established that the increase in infectious pancreatic necrosis prevalence is correlated with a new distinct pattern of outbreak distribution throughout the year. The role of smolt category (i.e. S1, S1/2 or S0), hence timing of seawater transfer as a strong correlating factor, is discussed.
Corpus al latum regulation of copulatory behaviour in the male grasshopper, Melanoplus sanguinipes
Authors: CHEESEMAN M. T. , GILLOTT C.
Published: September 2010

Abstract The relationship between corpus allatum (CA) regulation of copulatory behaviour and the CA's influence on the development of the accessory reproductive glands was studied in the male grasshopper, Melanoplus sanguinipes (Fabr.). Allatectomy slowed the development of copulatory behaviour; ≤80% of control males 7 days and older mated with females, but allatectomized males did not show comparable levels of copulation until day 19. In a 3 h observation period, the time taken for 50% of males to initiate copulation was c. 60 min for allatectomized males and only c. 10 min for controls. At the age when 50% of males copulated, the accessory glands of allatectomized males were less developed than those of controls; the accessory gland weight was 65%, soluble protein was 72% and reserves of long hyaline protein I were 40% those of controls. Treatment with Juvenile Hormone III on day 2 stimulated accumulation of long hyaline protein I in 9‐day‐old allatectomized males to the level found in untreated 19‐day‐old allactec‐tomized males, but did not elicit heightened copulation. No positive feedback from the accessory glands appeared necessary to elicit copulation since vasectomy, ablation of the accessory glands or isolation of the terminal abdominal ganglion by ventral nerve cord transection did not inhibit copulatory behaviour in 7‐day‐old males. Because allatectomy inhibited copulatory behaviour in 7‐day‐old males in which the accessory glands were removed but not in 19‐day‐old males without accessory glands, the increased tendency of older allatectomized males to mate with females was not due to release of inhibition caused by continued growth of the accessory reproductive glands.
Stage‐specific effects of Campoletis sonorensis parasitism on Heliothis virescens development and prothoracic glands
Authors: DOVER B. A. , VINSON S. B.
Published: September 2010

Abstract The ichneumonid endoparasitoid Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) injects a polydnavirus when it oviposits into a host. We compared the development of Heliothis virescens (F.) (Lepidoptera: Noctuidae) larvae parasitized in the penultimate (fourth) stadium with those parasitized in the last (fifth) stadium by C.sonorensis and show that hosts stung in the fifth stadium exhibited arrested or delayed development compared to the controls. Parasitoids developed normally to the point of emergence in larvae stung in the fifth stadium but most did not successfully emerge from the host. The prothoracic glands in all successfully parasitized fifth stadium hosts and most unsuccessfully parasitized fifth stadium hosts showed some degree of virally‐induced degeneration. Larvae stung in the fourth stadium developed more slowly than controls and either did not moult or developed to a fifth and sometimes a supernumerary sixth stadium before parasitoid emergence. Unsuccessfully parasitized hosts were delayed in their development but eventually moulted to the fifth and, in some cases, a supernumerary sixth stadium before pupating. Hosts stung in the fourth stadium showed no signs of prothoracic gland degeneration whether successfully parasitized or not. In addition, calyx fluid injections into early fourth stadium hosts did not cause prothoracic gland degeneration even after these hosts moulted to the fifth stadium, suggesting that degeneration induced by polydnavirus is specific to the last stadium of the host.
Electrophysiological and behavioural responses to lactic acid stimuli in larvae of Tenebrio molitor L. (Coleoptera: Tenebrionidae) and permeability of antennal sensilla
Authors: ALBERT P. J. , ZACHARUK R. Y. , WEAVER D. K. , McFARLANE J . E .
Published: September 2010

Abstract. Of the five types of antennal sensilla in larvae of Tenebrio molitor L., only the uniporous long pointed pegs and papillate plates are readily permeable to an aqueous solution of CoCl2, which is generally indicative of a gustatory function. An electrophysiological investigation confirms the gustatory role of the papillate sensilla on the antenna, and it suggests that they are responsible for mediating the behaviour of larvae toward lactic acid stimuli. Larvae with ablated antennae do not aggregate as would normal animals in the presence of lactic acid stimuli. The uniporous long pointed pegs show no response to lactic acid or other aqueous stimuli.
Environmental and physiological factors influencing phototactic flight of Bemisia tabaci
Authors: BLACKMER J. L. , BYRNE D. N.
Published: September 2010

Abstract. Experiments were conducted in a glasshouse and in the laboratory to determine the environmental and physiological parameters that affect flight behaviour of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). The number of whiteflies taking off and exhibiting a positive response to sky light in the glasshouse was greatest from 08.30 to 10.00 hours. During peak flight activity less than 5% of the population engaged in phototactic orientation. Temperature was the best single predictor for the phototactic response, accounting for 75% of the variability in whitefly ascent.

Sex ratios were determined for individuals remaining on poinsettia, Euphorbia pulcherrima (Willd.), and for individuals that exhibited phototactic orientation; both groups deviated from an expected 1:1 ratio. Males were more prevalent on the plants (1:0.76), whereas females were much more prevalent (1:3.02) among the whiteflies responding to sky light. A higher percentage of the females displaying a phototactic response contained eggs when compared to females remaining on poinsettia (87 v 65%). The two groups of females did not differ significantly in their weights, but males that remained on the plants were heavier than males that responded to sky light. Mark–recapture studies and experiments where phototactic individuals were removed from the population established that the response was short‐lived.

Whiteflies exhibiting a phototactic response in the glasshouse were more likely to exhibit long‐duration, phototactic flights in a vertical flight chamber when compared to individuals that remained on poinsettia (80.7 ± 6.7 v 36.0 ± 5.8% phototactic response; 7.0 ±3.2 v 0.7±0.2min flights). There was also less deviation in flight across the horizontal plane among the individuals that exhibited a positive response to sky light in the glasshouse in comparison to individuals that remained on their host. However, initial rates of climb were not significantly different between the two groups of whiteflies.
Influence of pheromone concentration and ambient temperature on flight of the gypsy moth, Lymantria dispar (L), in a sustained‐flight wind tunnel
Authors: CHARLTON RALPH E. , KANNO HIROO , COLLINS ROBERT D. , CARDÉ RING T.
Published: September 2010

Abstract. The effects of pheromone concentration and ambient temperature on male gypsy moth, Lymantria dispar (L.) (Lepidoptera), flight responses to pheromone were investigated in a wind tunnel. As the pheromone dose increased from 10 ng to 1000 ng, males flew at progressively slower airspeeds and ground speeds, and reduced their wingbeat frequencies. Furthermore, the moths steered significantly smaller course angles as the pheromone concentration increased, indicating that they were adopting a more upwind heading. The overall width of the flight tracks also decreased when males flew in more concentrated pheromone plumes. Estimation of plume dimensions using a male wing‐fanning assay showed that as pheromone dosage increased, the resultant active spaces became wider, indicating that an inverse relationship existed between the dimensions of the time‐averaged plume and the width of track reversals and that most turns were initiated within the plume. When males were flown at cool (20°C) and warm (26°C) ambient temperatures but to equivalent pheromone emission rates, they exhibited higher airspeeds and ground speeds at the higher temperature but steered larger course angles. Track widths, and length of track legs were, however, similar at the two temperatures. The mean turning frequency was nearly the same (c. 4 turns/s) across all the concentrations and temperatures tested even though the moths' thoracic temperature differed by 5°C when the ambient temperature was varied.
Impact of (Z)‐7‐dodecenol and turbulence on pheromone‐mediated flight manoeuvres of male Trichoplusia ni
Authors: LIU YONG‐BIAO , HAYNES KENNETH F.
Published: September 2010

Abstract. Turbulence and chemical noise are two factors which may influence pheromone‐mediated flight manoeuvres of a moth in natural habitats. In this study, the effects of turbulence and the behavioural antagonist (Z)‐7‐dodecenol on flight manoeuvres of male Trichoplusia ni (Hübner) were evaluated in a wind tunnel. Male moths increase airspeed and course angles when turbulence is increased. This leads to significant increases in the length of flight tracks, but significant reductions in the time taken to reach a pheromone source. In less disturbed pheromone plumes, distributions of course angles and track angles of male T.ni show a prominent peak centred about 0° relative to the upwind direction, indicating that moths can temporarily steer directly upwind toward a pheromone source.

When (Z)‐7‐dodecenol is released 10 cm upwind of a pheromone source to form an overlapping plume downwind, course angles, airspeeds and ground‐speeds of male T.ni are reduced significantly compared with those in uncon‐taminated pheromone plumes. This results in a longer flight time to reach a pheromone source. The decrease in flight speed would decrease the rate of contact with filaments, and thereby perhaps allow the moth to detect uncon‐taminated pheromone filaments independently from filaments containing the behavioural antagonist.
A comparison of the energetics of foraging of three species of Leptogenys (Hymenoptera, Formicidae)
Authors: DUNCAN F. D. , CREWE R. M.
Published: September 2010

Abstract. The three Leptogenys species L.nitida, L.schwabi and L.attenuata coexist in the coastal forests of South Africa and exhibit an array of foraging strategies ranging from individual foraging to group raiding. To determine whether there is a physiological basis for these strategies, the energetic cost of locomotion of individuals in these three species was determined. Carbon dioxide emission of voluntary running ants was measured using a flow‐through technique, in order to determine their metabolic rate when running. The minimum cost of transport was constant over a range of temperatures (20–35°C), and similar for all three species (common value 212.96 ± 17.35 Jkg_1m_1). A comparison of the energy required to sustain representative foragers at 25°C indicated that it was energetically less expensive for L. nitida workers to forage than for the other two species. This may explain why L.nitida uses group raiding, while the other two species use individual foraging with limited recruitment for retrieval of large food items.
Responses of rectal pumping to oxygen lack by larval Calopteryx splendens (Zygoptera: Odonata)
Authors: MILLER P. L.
Published: September 2010

Abstract. Larvae of most stadia of Calopteryx splendens (Harris) have been shown to pump water in and out of the rectum for much of the time. In each cycle of pumping there are from three to seven inhalant stokes which progressively fill the ileum with water. A short pause intervenes before a strong compression of segments 5–8 expels the water in a jet. The pattern resembles the gulping ventilation of aeshnid and libellulid dragonfly larvae. Larvae made hypoxic or otherwise stressed show a rise in the frequency and amplitude of pumping. The increase in frequency is brought about by a reduction of the pause duration, while the gain of amplitude results from a rise in both the number of inhalations/cycle and the magnitude of the stroke volume of each inhalation. Some evidence concerning the role of stretch receptors in the execution of the cycle is presented. It is proposed that rectal pumping promotes the exchange of ions and dissolved gases between the rectal water and the hindgut epithelia, supplying mainly the chloride‐absorbing cells in the rectal pads. Pumping also stirs the water in the vicinity of the caudal lamellae which are probably the insect's major sites of gaseous exchange.
Carbohydrate and lipid metabolism during the last larval moult of the tobacco hornworm, Manduca sexta
Authors: SIEGERT KARL J. , SPEAKMAN JOHN R. , REYNOLDS STUART E.
Published: September 2010

Abstract. At 25°C and with a light regime of 17 h light and 7h dark, the last larval moult of the tobacco hornworm, Manduca sexta, lasts approximately 32 h, during which profound changes of metabolism were observed. At the onset of the moult, which coincides with the cessation of feeding, the proportion of active fat body glycogen phosphorylase increased from 10 (‐2h) to 25–30% (Oh). A biphasic pattern with peak activities of 45–50% after t – 12 h and again just prior to the shedding of the cuticle (32 h) was subsequently observed. Haemolymph trehalose concentration decreased significantly from c. 35 (Oh) to 20mM (8h), but then recovered to an intermediate level (30mM; 12h). After completion of the moult, the trehalose concentration was 35–40 mM. The haemolymph glucose level in feeding fourth instar larvae was 4–5 mM, but decreased sharply before the onset of the moult to c. 1 mM, followed by a slow 6‐fold increase over the next 20h. Prior to the shedding of the cuticle, the glucose level dropped again dramatically. The haemolymph lipid level increased slowly from an initial level of 1.2–1.4mg/ml during the early part of the moult, reaching a maximum of 1.8mg/ml after /= 16 h. Afterwards, a decrease of c. 50% was observed until ecdysis occurred. Oxygen consumption per animal decreased steadily from 30–35 μl/min pre‐moult by approximately 70% to c. 10 μl/min but started to increase about 5 h before the animals resumed feeding.
Protein intake by gypsy moth larvae on homogeneous and heterogeneous diets
Authors: STOCKHOFF BRIAN A.
Published: September 2010

Abstract. Food selection behaviour, food utilization efficiency and growth performance of a generalist insect, the gypsy moth (Lymantria dispar (L.), Lepidoptera: Lymantriidae), were examined with respect to variation in food nitrogen concentration. The results suggest that gypsy moth do not suffer physiologically and in fact may benefit from intraplant variation by selective feeding. When provided with diet cubes containing identical nitrogen concentrations, control larvae tended to consume food from a single cube. This behaviour contrasted with that of larvae provided cubes differing in nitrogen concentration. These larvae tended to consume more from the high nitrogen cube, but allocated feeding more evenly among diet cubes than did control larvae. Overall, larvae mixed foods so as to obtain a mean concentration of 2.9‐3.2% nitrogen, a concentration assumed to approximate the ’intake target’. Larvae confined to single nitrogen concentrations mitigated the impact of imbalanced diets on body composition via both pre‐ingestive and post‐ingestive compensation. When confined to a specific nitrogen concentration, larvae adjusted their intake to the point of best compromise. In this case, this was the geometrically closest point to the estimated intake target. Larvae with a choice of foods that deviated more than ±1% from each other in nitrogen concentration grew as well as or better than larvae without a choice but given identical mean nitrogen concentrations. These results demonstrate that selectivity and nitrogen consumption by gypsy moth larvae are altered according to the particular choices available. Insects may benefit from intraplant variation in food quality because such variation provides the opportunity to choose foods and mix them in ways that permit close matching with the intake target. Variation may be particularly important to insects which must offset changing nutritional demands.