bluuebunny/crossref_metadata_2025 huggingface dataset:
l‐carnitine supplementation and lipid metabolism of rats fed a hyperlipidaemic diet
Authors: Eder K.
Published: March 2003

Until now, there has been no clear knowledge about the effect of dietary carnitine supplementation on lipid metabolism. Therefore, this study was conducted to investigate the effect of a dietary l‐carnitine supplementation (500 mg/kg) onx the lipid metabolism of adult rats. Rats fed a hyperlipidaemic basal diet containing 15% lard and 1% cholesterol were used as an animal model. The feeding period was 6 weeks. As parameters of lipid metabolism, the concentrations of individual lipids in plasma, lipoproteins and liver and the fatty acid composition of liver and erythrocyte total lipids were determined. There were no significant differences between the control group and the group receiving the diet supplemented with carnitine on parameters of animal performance (daily body weight gains and feed conversion ratio). As expected, plasma, very low‐density lipoproteins (VLDL) and liver exhibited high concentrations of cholesterol. Concentrations of triglycerides and phospholipids in plasma and individual lipoproteins as well as the concentrations of triglycerides, cholesterol and phospholipids in the liver were not significantly altered by dietary carnitine supplementation. The concentration of cholesterol in plasma and liver was increased by dietary carnitine. The fatty acid composition of liver and erythrocyte total lipids was not influenced by dietary carnitine supplementation. In conclusion, this study does not indicate a lipid‐lowering effect of dietary carnitine supplementation in hyperlipidaemic rats. Probably, the essential functions of carnitine in metabolism were realized by carnitine which was synthesized endogenously.
Effects of dietary Ca/P ratio, P level and microbial phytase supplementation on nutrient digestibilities in growing pigs: breakdown of phytic acid, partition of P and phytase activity along the intestinal tract
Authors: Seynaeve M. , Janssens G. , Hesta M. , Van Nevel C. , De Wilde R. O.
Published: March 2003

Eight female pigs (26–61 kg) provided with a simple T‐cannula about 10 cm proximal to the ileo‐caecal valve, were used in two experiments to investigate the effects of Ca/P ratio, P level and supplementation with phytase (500 FTU/kg) on the breakdown of phytic acid (IP6), partition of P and phytase activity along the alimentary tract in pigs. In experiment 1, two Ca/P ratios (1.5/1 and 2.2/1) and two P levels (0.34 and 0.47%) were tested according to a 2 × 2 factorial arrangement within a Latin square design. In experiment 2, the maize‐tapioca‐soybean meal‐based diets of experiment 1 were supplemented with phytase (500 FTU/kg). No lower inositolphosphates, but substantial phytase activities were detected in the ileal digesta and faeces. Significant faecal amounts of IP6 were found only for diets with a wide Ca/P ratio, due to its antagonistic effect on phytase activity. The addition of feed phosphate increased the proportion of inorganic P (Pi), but reduced the phytase activity in the small intestine. Breakdown of IP6 at the terminal ileum was 16.2% for the diets without phytase supplementation and was due to microbial activity. Supplementation with phytase tripled the pre‐caecal breakdown of IP6. However, the liberated Pi along the small intestine was not absorbed by the animal, but incorporated in microbial biomass as shown by lower organic matter (OM) disappearance and unaffected P disappearance ( Seynaeve et al.; J. Anim. Physiol. a. Anim. Nutr. 83, 36–48, 2000 ), increased phytase activity (+28%), higher organic nonphytate P fraction (+36%) and higher amounts of bacterial residues or intestinal cell debris residues (+43%) in the small intestine. The digestibility experiments indicate that P absorption from feed phosphate takes place to a large extent proximally to the ileo‐caecal valve. The phosphorus that is liberated by added microbial phytase from phytate in feedstuffs causes an increase in the microbial population in the small intestine of pigs but only becomes available for absorption by the pig in the caecum/colon region.
Effect of β‐carotene on health status and performance of sows and their litters
Authors: Kostoglou P. , Kyriakis S. C. , Papasteriadis A. , Roumpies N. , Alexopoulos C. , Saoulidis K.
Published: March 2003

A total of 48 sows were allocated to four groups (12 sows per group) at the 99th day of pregnancy and were treated throughout two consecutive breeding cycles, as follows: (a) control group: no treatment; (b) group BC1: 400 mg β‐carotene/sow/day via feed from 7 days prior to the expected farrowing, until the 30th day postservice; (c) group BC2: 400 mg β‐carotene/sow/day via feed from 7 days before weaning up to service, followed by 200 mg β‐carotene until the 30th day postservice; and (d) group BC inj: four intramuscular (i.m.) injections of 200 mg β‐carotene/sow (on the 100th day of pregnancy, on the day of farrowing, on the day of weaning and on the first day of oestrus). Serum β‐carotene equivalents, vitamin A and IgG concentrations were determined in sows at several times of the breeding cycle. Moreover, serum IgG concentrations were determined in piglets on the second day of lactation and at weaning. Data relating to sow reproductive parameters and litter parameters were also recorded. It was shown that concentrations of serum β‐carotene equivalents were elevated only in the BC inj group during lactation and at service, while serum vitamin A concentrations were also elevated in the BC inj group only at oestrus. There was no effect of β‐carotene on the oestrus intensity score, the weaning‐to‐oestrus interval, the number of returns to oestrus per sow and the farrowing‐to‐farrowing interval. The number of piglets born alive was greater in the BC inj group compared with the controls, while the litter size at weaning was greater in the groups BC1, BC2 and BC inj compared with the control group (p < 0.05). Supplementation of β‐carotene did not appear to influence the serum IgG concentration in sows and piglets.
Metabolic changes during the perinatal period in dairy sheep in relation to level of nutrition and breed. II. Early lactation
Authors: Bizelis J. A. , Charismiadou M. A. , Rodkais E.
Published: March 2003

The effect of level of nutrition during pregnancy was investigated on various plasma parameters, on energy intake, body weight, energy balance and milk yield, after parturition in two Greek dairy breeds. Thirteen Chios (CH) and 17 Karagouniko (K) pregnant ewes were assigned to groups A and B, which received 110% of their energy requirements for maintenance plus pregnancy for two foetuses and 90% of their maintenance energy requirements, respectively. After parturition all ewes were fed ad libitum. Body weights of group A and K ewes were higher (p 0.05) compared with group B and CH ewes, during lactation, although daily energy intakes tended to be greater in group B than in A ewes, during the first 3 weeks and in CH than K ewes (p 0.05), after the second week post‐partum. Total mean milk production was 114 ± 11 l and 82 ± 10 l for groups A and B (p 0.05) and 120 ± 12 l and 70 ± 7 l for CH and K ewes (p 0.001), respectively. Positive energy balance appeared after the day 15 and 7 of lactation, for groups A and B ewes and after the day 15 and 5 of lactation, for CH and K ewes, respectively. The group B and K ewes tended to have higher mean plasma glucose concentrations than group A and CH ewes, during early lactation. There were no significant differences in free fatty acids, β‐hydroxybutyric acid, insulin and T4 concentrations between A and B ewes. CH had higher free fatty acids (p 0.05) and β‐hydroxybutyric acid (p 0.05), and lower T4 (p 0.01) and insulin (p 0.05) concentrations than K ewes. It was concluded that under‐nutrition during pregnancy results in low milk yields of ewes fed ad libitum in early lactation, due to the poor development of the udder during late gestation.
Effect of nonessential amino acids on nitrogen retention in growing pigs fed on a protein‐free diet supplemented with sulphur amino acids, threonine and tryptophan
Authors: Křížová L. , Šimeček K. , Heger J. , Van Cauwenberghe S.
Published: March 2003

Two N balance experiments were conducted on growing pigs to study the effect of essential and nonessential amino acids added to a protein‐free diet on N retention. In Expt. 1, the addition of sulphur amino acids, threonine and tryptophan to a protein‐free diet at levels two times the maintenance requirements reduced (p > 0.1) daily N loss from –131 to –108 mg/kg0.75. A further addition of nonessential amino acids equivalent to 250 mg N/kg0.75/d resulted in a marked increase (p < 0.01) in daily N retention to 28 mg/kg0.75. In Expt. 2, nonessential amino acids were added to a protein‐free diet supplemented with sulphur amino acids, threonine and tryptophan at levels corresponding to 100, 200 and 300 mg N/kg0.75/d. N retention increased linearly as dietary nonessential N increased. The slope of the best‐fit regression line indicated that the marginal efficiency of nonessential N utilization for protein accretion was 0.26. The results suggest that nonessential amino acids may be a limiting factor for the re‐utilization of amino acids released by body protein breakdown or that they may serve as precursors for de novo synthesis of amino acids by gut microorganisms, thus contributing to the amino acid requirements of the pig.
A low‐selenium diet increases thyroxine and decreases 3,5,3′triiodothyronine in the plasma of kittens
Authors: YU S. , HOWARD (DECEASED) K. A. , WEDEKIND K. J. , MORRIS J. G. , ROGERS Q. R.
Published: March 2003

The effect of a low‐selenium diet on thyroid hormone metabolism was investigated in growing kittens. Twelve specific‐pathogen‐free kittens with ages ranging from 16 to 18 weeks were divided into two groups of equal number with equal sex distribution in each group. One group was fed a yeast‐based low‐selenium diet (0.02 mg Se/kg diet) while the other group was fed the same diet supplemented with Na2SeO3 at 0.4 mg Se/kg diet for 8 weeks. Food intake, body weight and body weight gain were not affected by the low‐Se diet during the study period. However, kittens given the low‐Se diet had significantly reduced plasma selenium concentration and glutathione peroxidase activity. Plasma total thyroxine (T4) increased and total 3,5,3′triiodothyronine (T3) decreased significantly in kittens fed the low‐Se diet at the end of the study. These results suggest that type I deiodinase in cats is a selenoprotein‐ or a selenium‐dependent enzyme.
Physiological traits in preterm calves during their first week of life
Authors: BITTRICH S. , MOREL C. , PHILIPONA C. , ZBINDEN Y. , HAMMON H. M. , BLUM J. W.
Published: March 2003

Morbidity and mortality of preterm neonatal calves are higher than of calves born at normal term, possibly and in part due to immaturity of physiological functions. Physiological parameters were therefore studied during the first week of life in seven preterm calves, born on day 277 of gestation after dams were injected prostaglandin F2αand flumethason. Calves were fed colostrum of the first milking for the first 3 days and from day 4 to day 7 the same colostrum diluted with milk replacer. Body weight increased during the first week of life by 2.2 kg. Heart rate and respiratory rate were always relatively high, whereas values of rectal temperature, blood gases, haematological, metabolic and endocrine traits were in the range and behaved similarly as is the experience in full‐term neonatal calves. Major exceptions were glucose and insulin, the concentrations of which barely rose postprandially, and growth hormone, the responses of which to growth hormone releasing factor analogue 1–29 were extremely variable and in part very small. In conclusion, calves born 2 week before normal term that survived the first week of life, although physiologically immature, were well able to handle ingested nutrients and to control their metabolism.
Host handling and specificity of the hyperparasitoid wasp, Dendrocerus carpenteri (Curtis) (Hym., Megaspilidae): importance of host age and species
Authors: Chow A. , Mackauer M.
Published: March 2003

The oviposition behaviour of Dendrocerus carpenteri (Curtis), an ectophagous hyperparasitoid of aphidiine wasps inside mummified aphids was examined. Hyperparasitoids were provided in the laboratory with pea aphids (Acyrthosiphon pisum) which had been parasitized by three different species of aphidiine wasps (Aphidius ervi, Ephedrus californicus and Praon pequodorum) ranging in physiological age from the late larval stage to the late pupal stage. Females accepted only the hosts inside mummified aphids; they ignored live aphids, and did not accept dead, but not yet mummified aphids, although the latter were sometimes probed with the ovipositor. Female behaviour in handling A. ervi or E. californicus mummies did not change with experience; handling and oviposition times were stereotypic. However, naive females needed experience to locate the cocoon of P. pequodorum and distinguish it from the empty aphid mummy. Host acceptance and specificity were influenced more by the developmental stage than the species of the primary parasitoid. In dichotomous choice tests, hyperparasitoids ‘preferred’ prepupae over younger pupae of A. ervi, but they did not distinguish between these stages of E. californicus; older pupae were accepted at a low rate. Host preference was not influenced by conditioning on the rearing host. We consider several constraints on the host range of D. carpenteri, and discuss alternative explanations of differential hyperparasitism in the field.
Effect of larval density on development and diapause of Sesamia nonagrioides (Lef.) (Lep., Noctuidae) under laboratory conditions
Authors: Fantinou A. A. , Tsitsipis J. A.
Published: March 2003

The effect of larval density on development and diapause of Sesamia nonagrioides (Lef.) was examined. Larvae were grown on an artificial diet at densities of five, 10, 20, 30 and 40 larvae per box, under two environmental (diapause‐including and diapause‐averting) conditions. High larval densities resulted in increased mortality under both experimental conditions tested. Although crowded larvae showed a higher pupation rate than those reared under low densities, small differences occurred between mean larval developmental time at different densities under developmental condition. In spite of this, crowding proved effective on the intensity of diapause of this species and the duration of diapause was shorter for crowded larvae. Pupal weights of both sexes were significantly reduced at high densities while there were significant differences between pupal weights formed by larvae reared under diapause conditions and those formed by larvae reared under nondiapause conditions at all density treatments. The pupal period was significantly longer under diapause conditions than that under development conditions but density was not found to play a role on the time of the emergence of the adults produced by larvae reared under developmental or diapause conditions.
Ostrinia nubilalis (Hb.) (Lep., Pyralidae) on sweet corn: relationship between adults caught in multibaited traps and ear damages
Authors: Maini S. , Burgio G.
Published: March 2003

Infestation with Ostrinia nubilalis (Hb.), the European corn borer (ECB) can be detected by using different sampling techniques in the field and statistical models aimed to assess the development time of ECB larvae and crop damage. An appropriate monitoring for this polyphagous species to show a relationship between the kind of sampling or a model and the subsequent damage in a particular crop, is very difficult. Sex pheromone traps, generally, are also not reliable for monitoring ECB. The possibility of employing new types of traps baited with a sex pheromone and a maize kairomone, the phenylacetaldheyde (PAA) (multibaited traps) was investigated. In sweet corn, trapping experiments were conducted over a 2‐year period with two kinds of cone traps (XLa and XLb) set up at the borders of fields (four replicates). ECB attacks of first and second generation larvae were evaluated in the corn ears as a percentage of damage and using a damage index (DI). A correlation was found between the number of females caught per trap and either the percentage of damaged ears (r = 0.73 for XLa; r = 0.65 for XLb) and the DI (r = 70 for XLa; r = 0.60 for XLb). Conversely, the number of males caught per trap was not correlated with ECB larval damage. A linear model of multiple correlation fitted to the data of simultaneous captures of males and females showed that the coefficients were not higher than simple correlation. The correlation coefficients obtained by fitting a curvilinear response surface were higher (r = 0.81 for XLa and r = 0.84 for XLb, respectively, related to percentage of damaged ears; r = 0.79 for XLa and r = 0.76 for XLb, respectively, related to DI) thus indicating that the simultaneous counting of males and females in cone traps can be an efficient and simple monitoring tool.
Larval parasitism of a forest pest, the common pine sawflyDiprion pini(L.) (Hym., Diprionidae), during an endemic density phase
Authors: Herz A. , Heitland W.
Published: March 2003

Abstract:Species composition and impact of larval parasitoids during an endemic density phase of a pine forest pest, the common pine sawflyDiprion pini(L.), were investigated by exposure of laboratory‐reared larvae of the sawfly to parasitoid attack in natural habitats. Colony‐associated host larvae of different instars were exposed continuously from early June until end of September of the years 1994 and 1995 in two pine stands with a different history of pine sawfly outbreaks. Host larvae were exchanged after a defined time interval and those collected up were examined in the laboratory for parasitism. Parasitoid assemblages were shown to be very species poor at both pine stands. The dominant species were the ichneumonidOlesicampe macellator andthe tachinidDrino gilva, which reached attack rates on the collected host larvae of 60 and 94%, respectively, during peak activity. The patterns of temporal attack, of multiparasitism, and of superparasitism of these dominant species were studied. In an additional experiment, the response of these species to different host‐patch sizes (number of host larvae per colony) were investigated. No aggregative response to higher host‐patch densities could be detected. The role and function of these larval parasitoids in the population dynamics ofD. piniare discussed.
Impact of flowers on the demography of western flower thrips Frankliniella occidentalis (Thysan., Thripidae)
Authors: Gerin C. , Hance TH. , Van Impe G.
Published: March 2003

The impact of flowers on the population growth of Frankliniella occidentalis was characterized on waxflower plants, Impatiens walleriana. In the presence of flowers, the populations grew exponentially while in their absence, the thrips populations only maintained themselves and showed no growth The difference in number and in size of thrips reared in both conditions suggested that the flowers were essential for the success of thrips development. In the presence of flowers, the distribution of females between the leaves and the flowers varied strongly according to the availability of flowers. By contrast, the proportion of first larvae in the flowers increased up to the last day of the experiment.
Semiochemicals associated to spacing behaviour of the bird cherry‐oat aphid Rhopalosiphum padi L. (Hem., Aphididae) do not affect the olfactometric behaviour of the cereal aphid parasitoid Aphidius rhopalosiphi De Stephani‐Pérez (Hym., Braconidae)
Authors: Gonzáles W. L. , Fuentes‐Contreras E. , Niemeyer H. M.
Published: March 2003

Volatiles produced by the interaction of Rhopalosiphum padi and wheat, and semiochemicals which elicit the spacing behaviour of R. padi on wheat and oat, were evaluated in an olfactometer against the cereal aphid parasitoid Aphidius rhopalosiphi. The parasitoid was attracted by volatiles produced by the R. padi‐wheat interaction at high density of aphids, but not by the R. padi‐wheat interaction at low density. Compounds produced by the interaction of wheat or oat that was infested with a high density of aphids (approximately 9 aphids/cm2), 6‐methyl‐5‐hepten‐2‐one (MHO), 6‐methyl‐5‐hepten‐2‐ol (MHOH), 2‐tridecanone (2‐T), and methyl salicylate (MS), neither attracted nor repelled A. rhopalosiphi as pure compounds or in the naturally occurring mixture. The results are discussed in terms of the use of semiochemicals and parasitoids in the integrated management of aphid pests.
Strategies of aphidophagous predators: lessons for modelling insect predator–prey dynamics
Authors: Kindlmann P. , Dixon A. F. G.
Published: March 2003

Both theoretical and empirical evidence indicate that in systems where insect predators have longer developmental times than their prey the predators have little impact on the abundance of their prey. In assessing the ‘effectiveness’ of a predator for biological control one should take into account that selection maximizes predator fitness, not its effctiveness as a biocontrol agent. Therefore, predators that have a long developmental time relative to their prey are unlikely to be the best biocontrol agents. If these results can be generalized to other predator–prey systems, then it is clear that an understanding of predator–prey dynamics can only be achieved by studying predators.
Integrated pest management of Ips pini (Col., Scolytidae) populations in south‐eastern Montana
Authors: Gara R. I. , Millegan D. R. , Gibson K. E.
Published: March 2003

Second growth ponderosa pine forests of the Northern Cheyenne Reservation of south‐eastern Montana sustained a chronic Ips pini outbreak between 1978 and 1994. Studies determined the emergence and seasonal flight patterns of the scolytids with regards to temporal and spatial distribution of host material as well as population changes during the year. These changes related to the dry‐down rate of host material (thinning and logging slash) and the availability of slash; an index of population change (IPC) was developed to estimate seasonal changes in the Ips population from spring to autumn. Principal management components of an integrated pest management system included (1) an emphasis on creating thinning and logging slash between August and December, a time that provides quickly degrading host material for the overwintering Ips population while not providing suitable host material for the subsequent spring flight; (2) restrictions on winter logging as slash produced during this period provided suitable hosts for the first spring flights of I. pini; and (3) restrictions on the use of trap logs or pheromones to lower Ips populations as these materials provide kairomones for the predators (Enoclerus lecontei, Enoclerus spegeus and Temnochila chlorodia) that partition their I. pini host across the spring, summer and autumn.
Haemocytes of the hemlock woolly adelgid Adelges tsugae Annand (Hom., Adelgidae) and changes after exposure to low temperatures
Authors: Gouli V. , Parker B. L. , Skinner M.
Published: March 2003

The main cellular components of the haemolymph of Adelges tsugae Annand were identified from individuals collected in Massachusetts, USA in February and October 1997. The cell types present were formative cells, plasmatocytes, adipohaemocytes, vermiform cells, prohaemocytes and oenocytoids. Vermiform cells were the most abundant. Very few oenocytoids were found. They were significantly more cells of all types in the haemolymph of A. tsugae collected in October than in those collected in February. Adelges tsugae collected in February were exposed in the laboratory to ‐20, ‐25 and ‐30°C for 2, 4 and 8h. No intact cells were found in the haemolymph of A. tsugae exposed to ‐30°C. Haemocytes were damaged by exposure to ‐20 and ‐25°C. The effect of these temperatures on the different cell types is presented.
Wirkung von Larvenkot von Dendrolimus pini L. (Lep., Lasiocampidae)nach Fraß an Kiefer auf Keimung und Keimlingswachstum von Kiefern‐, Birken‐und Eichensaat
Authors: Jung P. , Lunderstädt J.
Published: March 2003

Abstract: Germination and growth of Pinus sylvestris L., Betula pendula Roth. and Quercus robur L. were investigated under laboratory conditions. Sterilized sand was used as the substrate and supplied with (a) increasing amounts of faeces of larvae of Dendrolimus pini L. which had been reared previously on Scotch pine and (b) a solution of NH4NO3 of the same N‐concentration as the faeces. The germination of pine and birch decreased strongly with increasing amounts of faeces, whereas the germination of oak was unaffected. When the inhibition of germination was overcome the further growth proceeded according to the species‐specific growth pattern during a period of 200 days (oak) and 300 days, respectively (pine, birch). It was influenced neither by the supply of faeces nor of fertilizer. It is concluded from the results that the faeces of phytophagous insects contain inhibitory components which become effective only during the germination process of the species if there is a poor supply of nutrients in the seed (pine, birch). The subsequent stage of germ growth however, is not affected. The results are discussed in terms of a possible ecological function for insects as regulators of the species composition following mass propagations.
Age‐dependent fecundity and life‐fertility tables for Podisus nigrispinus (Dallas) (Het., Pentatomidae)
Authors: Medeiros R. S. , Ramalho F. S. , Lemos W. P. , Zanuncio J. C.
Published: March 2003

Abstract: The reproductive potential and longevity of Podisus nigrispinus (Dallas) were determined under laboratory conditions at a constant temperature of 25°C. The data were used to calculate life‐fertility tables and rates of increase. The fecundity plateau of P. nigrispinus lasted 18 days, and during this period mean fecundity was 8.89 eggs per female per day. It started at the eighth day of age and ended at the 18th day of age. The declining fecundity period started at 18 days of age and ended with the death of the females. The female of P. nigrispinus oviposited a mean of 188.54 eggs, and had a mean longevity of 31.21 days. The gross reproductive rate (GRR) was 104.374 females/female; the net reproductive rate (Ro) was 31.945 females/female; the generation time was 47.390 days; the doubling time was 9.480 days; the intrinsic rate of increase (rm) was 0.073, and the finite rate of increase (λ) was 1.076. The predator population increased by 16.61 adult progeny per female per generation in the laboratory.
Attractiveness for Ceratitis capitata (Wiedemann) (Dipt., Tephritidae) of mango (Mangifera indica, cv. Tommy Atkins) airborne terpenes
Authors: Hernández‐Sánchez  , Sanz‐Berzosa  , Casaña‐Giner  , Primo‐Yúfera
Published: March 2003

The airborne volatiles of the Tommy Atkins cultivar of mango (Mangifera indica L.), a fruit frequently damaged by Ceratitis capitata, were analysed by aeration of fresh fruits, adsorption and thermal desorption coupled to gas chromatography–mass spectrometry. Ethanol and acetic acid were identified as the major components, together with longifolene, which has not been described before in the mango aroma and other terpenes (α‐pinene, 3‐carene, p‐cymene, limonene and α‐terpinolene). The attractiveness of the identified terpenes for C. capitata was tested in laboratory cages and the results showed that p‐cymene and limonene were the best terpene attractants for both males and females.
Oviposition by Mamestra brassicae (L.) (Lep., Noctuidae) in relation to age, time of day and host plant
Authors: Rojas  , Wyatt  , Birch
Published: March 2003

The age at which females begin to lay, the daily pattern of oviposition, the influence of host‐plant material on egg‐laying as well as the host preference of Mamestra brassicae L. (Lep., Noctuidae) were investigated under laboratory conditions. The females began to oviposit during the third, fourth and fifth scotophase after emergence. A great variability in daily female fecundity was observed. The highest level of oviposition occurred during the fifth day. Females oviposited during the whole scotophase, but maximal oviposition occurred during the second hour. The females without host‐plant material laid fewer eggs than females with host‐plant material (cabbage leaves Brassica oleracea var. capitata). In two‐choice tests, the females preferred to oviposit on cabbage rather than chrysanthemum, but there was no difference in the mean number of eggs laid on cabbage and tomato. There were significantly greater mean numbers of total eggs deposited on tomato than on chrysanthemum.
Effects of environmental factors on virulence of the entomopathogenic fungus, Nomuraea rileyi, against the corn earworm, Helicoverpa armigera (Lep., Noctuidae)
Authors: Tang  , Hou
Published: March 2003

The effects of environmental factors on infection of the entomopathogenic fungus, Nomuraea rileyi, isolated from the corn earworm, Helicoverpa armigera, in Taiwan, to its host insect were studied in the laboratory. The fungus caused higher larval mortality at 20°C than at 30°C when 5 × 106 conidia/ml were sprayed on the fourth instar. However, mortality of the fifth instar injected with 1 × 103 conidia/larva was not significantly different when the inoculated larvae were incubated from 15 to 30°C. The fungal development in inoculated larvae was best at 20 and 25°C after shifting from 20°C to either lower or higher temperatures. The germination rate was higher at 20 and 25°C than at 30 or 35°C. Conidial germination was better on the wash‐off of insect cuticle than on Sabouraud maltose agar with yeast extract. Sporulation on chill‐dried cadavers was maximal at 95 or 100% relative humidity than at lower levels of relative humidity. The time required for sporulation was 2 days less at 100% than at 95% relative humidity. Although photoperiod did not affect fifth instar mortality caused by N. rileyi, the median lethal time (LT50) values were shorter upon incubating under light than in darkness. Incubation of infected cadavers under 12 or 24 h light resulted in 20‐fold more conidial production than under full darkness. Therefore, illumination is necessary for development of this isolate on insect cadavers.
Leaf volatiles as attractants for neonate Helicoverpa armigera Hbn. (Lep., Noctuidae) larvae
Authors: Singh A. K. , Mullick S.
Published: March 2003

The 1st instar Helicoverpa armigera larvae were bioassayed in the laboratory to study their orientational responses towards leaf volatiles of four leguminous crops: chickpea, Cicer arietinum L.; pigeonpea, Cajanus cajan Millsp.; blackgram, Vigna mungo L.; and cowpea, Vigna unguiculata L. (Walp.). The gram podborer larvae showed positive orientational responses towards leaves of all four test plants. Whole leaves of chickpea, pigeonpea and blackgram were more attractive for gram podborer larvae than cowpea whole leaves. Larval attraction for crushed (damaged) leaves of chickpea, blackgram and cowpea was significantly higher than the attraction for pigeonpea crushed leaves. The orientational responses of gram podborer larvae for crushed leaves of cowpea were significantly higher compared to whole leaves. However, the whole pigeonpea leaves elicited higher orientational responses than the crushed leaves. Maceration was not observed to affect the attractancy of chickpea and blackgram leaves. Further, the leaves were extracted in n‐hexane and methanol. It was observed that the crude extracts of all the test leaves elicited positive orientational responses of larvae. In no‐choice tests, the orientational preference of the larvae for the hexane extracts of all the test leaves was statistically equal. Similarly, the methanol extracts of leaves of all the test plants also attracted a greater percentage of larvae in no‐choice tests. However, under two‐choice bioassays, hexane foliage extract of all the test plants elicited higher orientational responses of larvae compared to the methanolic extracts of same leaves. The results of these bioassays clearly indicate that all the test leaves emit kairomones for gram podborer larvae. Moreover, kairomonal components of these leaves are, at least in part, extractable in hexane and methanol, which are higher in hexane than methanol.
Studies on the activity of the alkaline phosphatase in the midgut of infected silkworm, Bombyx mori L.
Authors: Miao Y.‐G.
Published: March 2003

The effects of several factors on the activity of alkaline phosphatase (ALKP) in the midgut of the silkworm, Bombyx mori L were studied. The ALKP activity varied greatly among the tested strains. There was positive correlation between ALKP activity and cocoon quality. The ALKP activity of the midgut decreased when the silkworm was infected with cytoplasmic polyhedrosis virus (CPV); whereas, infection with nuclear polyhedrosis virus (NPV) did not affect ALKP activity. This suggests that the pathogenic mechanism of CPV differs from that of NPV. Bacillus thuringiensis caused direct damage to the midgut tissues of the silkworm with a rapid decline in ALKP activity. Activation of ALKP by Mg2+ was more evident than the other chemicals. Ascorbic acid, Ca2+, citric acid and Cl– were inhibitory to ALKP in vitro.
Impact of predators on artificially augmented populations of Lymantria dispar L. pupae (Lep., Lymantriidae)
Authors: Gschwantner T. , Hoch G. , Schopf A.
Published: March 2003

The impact of predators on artificially augmented populations of Lymantria dispar pupae (Lep., Lymantriidae) and the species composition of the predator community were investigated in two oak stands in eastern Austria. The population density of L. dispar has been at innocuous levels for several years at both sites. From mid‐June to mid‐July, we created artificial prey populations by mounting gypsy moth pupae with beeswax on burlap bands placed at the base, 25, 50 and 100 cm height on 25 trees at each site. A total of 6600 pupae were exposed at each site. A total of 92% of exposed pupae were destroyed by predators, at site I (with dense understorey vegetation) whereas 67% were destroyed on site II (with sparse understorey vegetation). Initially, pupal mortality was highest at the base of trees, but differences in mortality among the four locations where pupae were exposed decreased during the course of the study period. Spatial differences in predation were ascertained, suggesting that the aggregation of small mammals, for example, is related to patches of dense shrub vegetation. Pupal mortality was primarily caused by mice (46.3% at site I and 36.4% at site II). Many exposed pupae simply disappeared (40.4% at site I and 22.8% at site II). Calosoma spp. and other invertebrate predators caused very little mortality among L. dispar pupae (5.5% at site I and 7.8% at site II). Trap catches on separate study plots at both sites revealed that Apodemus flavicollis (Rodentia, Muridae) was the most important predator species present, whereas Apodemus sylvaticus (Rodentia, Muridae) and Clethrionomys glareolus (Rodentia, Arvicolidae) were captured in low numbers.
Determinants of the size of aphid–parasitoid assemblages
Authors: Stadler B.
Published: March 2003

Abstract: Aphid parasitoids have to cope with a range of different life‐history features of their hosts in terms of size at maturity, abundance, ant‐attendance, host specificity, host alternation and many more. Their hosts often show large fluctuations in numbers during a season or in different habitats and the plants they live on strongly shape their performance. Plant characteristics (i.e. life form, ecological strategy, light exposure, nutrient provision, habitat type) also affects the environment of aphids and their associated parasitoids. Using data restricted to Central European aphids and their primary parasitoids, effort is directed to identifying significant ecological variables, which might influence the diversity of parasitoid assemblages in aphids. Most parasitoid species were reported from the Aphidini and Macrosiphini. Aphids, which are very abundant, host‐alternating, polyphagous and live on grasses appear to support larger parasitoid assemblages than those which are less abundant, non‐host‐alternating, mono‐ or oligophagous and feed on trees or herbs. Obligate myrmecophiles support fewer parasitoids than facultative myrmecophiles. Different degrees of mobility, the production of wax wool and alate adults did not have significant effects on parasitoid numbers. Discriminant function analysis using different degrees of ant attendance as dependant variable indicated that aphid specific characters and the number of primary parasitoids contributed most to the separation of the groups. Plant specific characters seem to contribute little to the development of different degrees of myrmecophily and parasitization patterns.
Apple sawfly Hoplocampa testudinea (Hym., Tenthredinidae) and its parasitoid Lathrolestes ensator in Dutch apple orchards (Hym., Ichneumonidae, Ctenopelmatinae)
Authors: Zijp J. P. , Blommers L. H. M.
Published: March 2003

Abstract:  Changes in population densities of the apple sawfly Hoplocampa testudinea (Klug) and its parasitoid Lathrolestes ensator (Brauns) were monitored in 15 apple orchards for a period of up to 4 years. The parasitoid species was found in all orchards except one, and was more numerous in plantings on sandier soils. Post‐bloom insecticide applications against other pests, and carbaryl for fruit thinning, often decimated both host and parasitoid in integrated pest management orchards. In organic orchards, where synthetic pesticides are banned, and Quassia is the only remedy against sawfly, the pest is more problematic. The low levels of parasitism in all organic orchards, except one, were possibly due to the application of wettable sulphur during the parasitoid flight period. The sawfly usually recovers more quickly than its parasitoid when chemical control is discontinued, because propagation of L. ensator is limited in various ways. The parasitoid is time limited, because suitable second instar host larvae are rarely available for more than a week on a single apple variety. Moreover, parasitism levels stay moderate because the parasitoid females do not avoid superparasitism. Finally, relatively more sawflies than parasitoids emerge after 10 months underground, because the incidence of prolonged diapause is more elevated in L. ensator than in the sawfly. It is suggested that both the high incidence of prolonged diapause and the inability to avoid superparasitism are useful in reducing the risk of local extinction. Elevated sawfly attack in a single early apple variety would reduce exploitation of suitable host larvae in other nearby varieties, in as far as the parasitoid is not able to distinguish fruitlets with accessible second instar host larvae from those with inaccessible older larvae. Although the former are available for a limited time, the latter may keep the parasitoids from moving to the less abundant second instar larvae in late(r) varieties. Reduction of elevated host density in such an early variety by a properly timed application of a short‐lived pesticide, such as Quassia, increases parasitism levels proportionally, and is expected to promote parasitoid movement to host larvae in other varieties nearby.
Impact of the parasitoidLathrolestes ensator(Hym., Ichneumonidae, Ctenopelmatinae) as antagonist of apple sawflyHoplocampa testudinea(Hym., Tenthredinidae)
Authors: Zijp J. P. , Blommers L. H. M.
Published: March 2003

Abstract:Lathrolestes ensator(Brauns) was the only parasitoid species reared from larvae of apple sawflyHoplocampa testudinea(Klug) collected in Dutch orchards. The life history parameters of apple sawfly and its parasitoidL. ensatorwere investigated in field and semi‐field experiments. Usually, the adult parasitoids emerge in synchrony with the preferred host stage, the second instar sawfly larvae. Parasitoid females carried 120–175 eggs, but never laid more than half this number. The mortality of sawfly eggs and larvae varied from 75 and 99%. The eggs and mining larvae are most vulnerable, as the older larvae survive for 90% on average. Three factors at least determine how many of the descending larvae become adult sawfly or parasitoid next spring. The failure of descending larvae to construct a cocoon varied from 7 to 31% and was highest in clay soil. Probably a similar mechanical hindrance prohibited more emerging adults, of both sawfly andL. ensator, from attaining the surface in heavier soils next spring. Relatively more sawfly prepupae than parasitoids died in the cocoon stage, from fungus disease or other causes, but more parasitoids than hosts stayed in prolonged diapause. Mainly due to this last factor, the overall result was a decrease of the parasitoid : host ratio during the first season underground. A life table based on survival rates during various life stages yields a net reproductive rate of up to 2.4 daughters per female sawfly. It indicates that 60% of the sawfly larvae need to be parasitized to stop population growth, or correspondingly less when more than 75% of the host eggs and young larvae are killed by predators or other causes.
The problems and prospects of integrated control of Agonoscena pistaciae Burck. and Laut. (Hom., Sternorrhyncha) in Greece
Authors: Souliotis C. , Markoyiannaki‐Printziou D. , Lefkaditis F.
Published: March 2003

Abstract: A study of the role of natural enemies of Agonoscena pistaciae Burck. and Laut. populations, in a pistachio orchard located in the Makrakomi area of Central Greece, was carried out during 1999–2000. Agonoscena pistaciae is economically the most important psyllid species of pistachio in Greece and causes considerable damage. Its adult population evaluation is clearly distinguishable in two phases. The first phase, from early April until the end of July, is characterized by slow population development. In the second phase, from the end of July until the fall of the leaves, the population density of this insect increases rapidly and reaches high levels. During this second phase, the presence of the predator insects Chrysoperla carnea Steph., Anthocoris nemoralis F and of the parasitoid Psyllaephagus pistaciae Ferriere is noteworthy. Among these, the most important is the parasitoid, which appears in satisfactory numbers between the end of July and the end of September/beginning of October and plays a significant role in reducing the populations of A. pistaciae that are on the point of hibernating.
Composition of the volatiles from intact and tea aphid‐damaged tea shoots and their allurement to several natural enemies of the tea aphid
Authors: Han Bao‐yu , Chen Zong‐mao
Published: March 2003

Abstract: The comparison between the composition of the volatiles from intact tea shoots (ITS) and that from tea aphid‐damaged tea shoots (TADTS) was accomplished, and the difference of both volatiles in attraction to natural enemies of the tea aphid, Toxoptera aurantii, i.e the ladybug, Leis axyridis (Pallas), the aphid parasite, Aphidius sp., and the lacewing, Chrysopa septempunctata Wesmeal, was investigated in the current paper. Volatile components from ITS, obtained by air entrainment, were identified by their mass spectra and retention times and comfirmed by comparison with authentic samples. They are E‐2‐hexenal, ocimene, Z‐3‐hexenyl acetate, Z‐3‐hexen‐1‐ol, butanoic acid‐3‐hexenyl ester, linalool, 1‐octanol, geraniol and indole. Volatiles from TADTS have been identified as E‐2‐hexenal, ocimene, Z‐3‐hexenyl acetate, Z‐3‐hexen‐1‐ol, linalool, geraniol, indole, benzaldehyde and E‐2‐hexenoic acid. Z‐3‐hexen‐1‐ol is the main component in the two kinds of volatiles, whilst benzaldehyde is the another main component in TADTS volatiles. The air entrainment extracts of TADTS and benzaldehyde elicit the stronger electroantennogram (EAG) responses, and the stronger upwind flight and arresting behaviour from each natural enemy in wind tunnel. EAG responses from Leis axyridis and Chrysopa septempunctata were bigger than those from Aphidius sp., whereas Leis axyridis responds to these odours slightly less than Aphidius sp. and Chrysopa septempunctata in wind tunnel bioassay. So TADTS emits volatile synomones, in which the amount of benzaldehyde is ample and its allurement is the strongest.
Performance of Hungarian phylloxera strains on Vitis riparia rootstocks
Authors: Kocsis L. , Granett J. , Walker M. A.
Published: March 2003

Abstract: Vitis riparia and other rootstocks were used in excised root‐ and plantlet culture‐bioassays to test the performance of Hungarian colonies of phylloxera. Phylloxera colonies from America and Germany were used as comparisons. The Hungarian colonies had a higher level of performance on V. riparia in contrast with the American and German colonies. Plantlet assays found the performance of a Hungarian strain on V. riparia equivalent to that on Vitis vinifera, AXR#1 and 41B root types. In contrast, the American colonies did not survive on V. riparia. Collections of Hungarian gallicole colonies from cultivated and escaped rootstock leaves were assayed using excised roots of the rootstock Teleki 5C. Results indicated that performance of phylloxera collected from feral rootstocks was higher than performance of colonies collected from cultivated rootstock leaves. Lastly, when the attached roots of field‐grown V. riparia vines were damaged by girdling, phylloxera performance was much higher than on undamaged roots, suggesting cultural conditions can increase the risk of related vine damage. These laboratory and field results show that V. riparia is capable of supporting phylloxera on its roots. Escaped, feral vines may select for phylloxera with increased virulence on roots. This is of significance in regions such as Hungary where feral rootstock is common.
Searching and oviposition behaviour of Amitus fuscipennis, a parasitoid of the greenhouse whitefly
Authors: Manzano M. R. , van Lenteren J. C. , Cardona C.
Published: March 2003

Abstract: Amitus fuscipennis MacGown & Nebeker (Hym., Platygasteridae) is a parasitoid of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hom., Aleyrodidae) on some crops as bean and snap bean (both Phaseolus vulgaris L.) in Colombia. The searching and oviposition behaviour of A. fuscipennis was studied in the laboratory, using T. vaporariorum as a host on bean leaves. The parasitoid's basic search pathway consisted of walking, encountering the host, and drumming and probing it. While walking, the parasitoid stopped for short periods of time, partly to preen itself. Walking while searching comprised 61% of the adults’ time budget and probing hosts represented 16%. After a host nymph was parasitized by A. fuscipennis, the parasitoid remained close by and continued searching for new hosts in the immediate vicinity. Such behaviour suggests area‐restricted searching. The parasitoid preferred first instars of T. vaporariorum for oviposition, resulting in long developmental times. Amitus fuscipennis had a high percentage of host acceptance resulting in a high percentage parasitism (60%) of all encountered hosts. Amitus fuscipennis, on average, walked faster before an oviposition (1.4 mm/s) than other whitefly parasitoids. The implications of these findings for the control of T. vaporariorum are discussed.
The potential attractant or repellent effects of different water types on oviposition in Aedes aegypti L. (Dipt., Culicidae)
Authors: Navarro D. M. A. F. , De Oliveira P. E. S. , Potting R. P. J. , Brito A. C. , Fital S. J. F. , Sant'Ana A. E. Goulart
Published: March 2003

Abstract:  The selection of oviposition sites by the yellow‐fever mosquito, Aedes aegypti, was studied in the laboratory. The repellent or attractant effects of salinity and the presence of bacteria in water collected from a local community on the Brazilian coast were investigated. Water contaminated with bacteria (waste water and lagoon water) elicited significantly more oviposition than distilled water. Oviposition decreased with an increase in salinity, with almost no oviposition above 12%. The salinity tolerance of A. aegypti larvae was investigated by measuring their mortality in response to salt concentrations ranging from 10 to 15%. The LD50 of salt for A. aegypti larvae was around 13%.