bluuebunny/crossref_metadata_2025 huggingface dataset:
Genetic and environmental influences on size of first litter in sheep, estimated by the REML method
Authors: Hagger By C.
Published: March 2003

Fixed effects of age at first litter and of season of lambing as well as variance components for additive genetic, flock × year and sire of litter effects on size of first litter were estimated for an animal model by a derivative‐free REML procedure. Data of the four Swiss sheep breeds White Alpine (WAS), Brown‐headed Meat (BFS), Black‐Brown Mountain (SBS) and Valais Black Nose (SN) were available. Number of first litters used were 21 384, 21 607, 15 013, 12 394 and 18 110 the WAS (two data sets, WAS1, WAS2), BFS, SBS and SN, respectively. Litter size of ewes lambing the first time at 2 years of age was 0.27, 0.31, 0.41, 0.46 and 0.26 lambs larger than of ewes lambing the first time at 1 year of age. The largest increase occurred for the two breeds (BFS, SBS) with the lowest average age at first litter. The largest difference between any two lambing seasons within breed were 0.16, 0.16, 0.29, 0.22 and 0.07 lambs. Estimates of additive genetic variance of size of first litter were between 0.0269 (SN) and 0.0765 (SBS). Heritability estimates for this trait were 0.171, 0.156, 0.114, 0.225 and 0.122 for WAS1, WAS2, BFS, SBS and SN, respectively. A large flock × year component (relative to phenotypic variance) of 0.148 was found for SN, compared with estimates between 0.042 and 0.067 for the other breeds. A sire of litter component (relative to phenotypic variance) of 0.066 was found for SN, compared with estimates between 0.016 and 0.039 for the other breeds. It can be concluded that all nongenetic effects investigated should be taken into account for the estimation of additive genetic variance and breeding values for size of first litter, and that considerable variation in size of genetic and nongenetic effects exists in the sheep breeds under consideration.
Including coefficients of inbreeding in BLUP evaluation and its effect on response to selection
Authors: Mehrabani‐Yeganeh H. , Gibson J. P. , Schaeffer L.R.
Published: March 2003

Stochastic simulation was used to study the effect on selection response of accounting for inbreeding versus ignoring it in the construction of the inverse of the relationship matrix used in mixed model equations (MME) to obtain BLUP of breeding values. Three different heritabilities of 0.10, 0.25, and 0.50 and two different family structures were used. Selection of replacement animals was based on best linear unbiased predictors (BLUP) of breeding values using an animal model. Average inbreeding coefficients (F) were in the range of 0.4–0.5 after 11 generations of selection. Even with such high inbreeding levels, no significant differences in selection responses were found between accounting or ignoring F in MME construction over the range of heritabilities and family structures.
Reducing the effect of parent averages from animal solutions in mixed model equations
Authors: Wu L. , Schaeffer L. R.
Published: March 2003

Selection of animals based on their BLUP evaluations from an animal model results in animals that are closely related which leads to increased rates of inbreeding. The tendency for higher inbreeding rates is greater at low heritability values. Several attempts have been made to reduce the impact of parent average breeding values from animals evaluations in order to reduce inbreeding while not sacrificing genetic response. A method that modifies the rules for forming the inverse of the additive genetic relationship matrix for use in best linear unbiased estimation of breeding values via an animal model was developed. This method and several others were compared analytically and empirically, from the perspective of partitioning the animal solutions into contributions from the data, from progeny, and from the parent average. The ratio of genetic progress to average level of inbreeding showed that the modified relationship matrix method was superior to the other methods. Similar results could be obtained by using artificially high heritability in a usual BLUP analysis.
Genetic variation within and relationships among populations of Asian goats (Capra hircus)
Authors: Barker  , Tan  , Moore  , Mukherjee  , Matheson  , Selvaraj
Published: March 2003

Genetic variation at 59 protein coding loci (16 polymorphic) and 25 microsatellite loci was analysed for 11 indigenous south‐east Asian goat populations, and the Australian feral population, to determine the magnitude of genetic differentiation and the genetic relationships among the populations. Significant deviations from Hardy–Weinberg equilibrium were detected in one or more populations for eight of the nine protein loci with codominant alleles, and for microsatellites for all except the two Sri Lankan populations and for all but four loci. For both marker types, average inbreeding coefficients (FIS) were exceptionally high. Heterogeneity of deviations from Hardy–Weinberg equilibrium for the microsatellites showed no differences for among loci within populations as compared with among populations within loci. For protein loci, however, the former was higher, indicating selection affecting allele frequencies at some loci. The variance among protein loci was significantly higher than among microsatellite loci, further indicating selection at some protein loci. There was significant differentiation among populations for both protein and microsatellite loci, most likely reflecting the geography of south‐east Asia, and the presumed spread of goats throughout the region. Phylogenies derived from pair‐wise genetic distance estimates show some similar clustering for the microsatellite and protein based trees, but bootstrap support was generally low for both. A phylogeny based on the combined set of 38 protein and microsatellite loci showed better consistency with geography and higher bootstrap values. The genetic distance phylogeny and the Weitzman diversity tree derived from microsatellite data showed some identical clusters, and both identified the Ujung Pandang and Australia populations as contributing most to overall genetic diversity.
Molecular genetic characterization of Robertsonian translocations in cattle
Authors: Joerg H. , Garner D. , Rieder S. , Suwattana D. , Stranzinger G.
Published: March 2003

The chromosome fusion of acrocentric chromosomes, known as Robertsonian translocations, are the most common chromosome rearrangement in Bovidae. Cytogenetic studies revealed differences between the centromeres of Robertsonian translocations: the rob(1; 29) is called monocentric, whereas rob(14; 20) is a dicentric chromosome. To analyse the type of fusion, satellite sequences were hybridised to metaphase chromosomes of carriers of rob(1; 29) from different breeds and rob(14; 20) from the Simmental breed. A repeat element of the bovine 1.715 satellite was located in the centromeric regions of all 29 bovine acrocentric chromosomes. No signals were observed on either the X‐,Y‐ or the rob(1; 29) chromosomes. In contrast, all rob(14; 20) chromosomes gave a distinct hybridisation signal. Microsatellite markers in the linkage group, originating from the fusion, revealed a characteristic allele combination for rob(1; 29) in all carriers and were able to confirm the screening of metaphases of 220 daughters of a heterozygote carrier of the rob(1; 29). The results indicate that rob(1; 29) lost parts of both centromeres and that the 1.715 satellite DNA is not necessary for the functioning of the centromere. Furthermore, rob(1; 29) appears to derive from the same mutation and is transmitted according to Mendelian law.
Estimation of genetic parameters of type traits in Asturiana de los Valles beef cattle breed
Authors: GUTIÉRREZ J. P. , GOYACHE F.
Published: March 2003

Ten type traits and a final score were analysed in 5868 records of the Asturiana de los Valles beef cattle breed. Traits were grouped into two classes: (i) traits scoring skeletal and muscular development and (ii) traits scoring adjustment to the breed standard. Heritabilities were moderate to low, ranging from 0.04 to 0.26. Genetic correlations among traits were, in general, in the same direction as, but higher than, phenotypic correlations. The genetic variability shown, in general, for the analysed traits would justify the inclusion of morphological assessment in the Asturiana de los Valles beef cattle breed sire selection programme. Main characteristics of the current type classification system are criticized. The knowledge of (co)variances among type and economically important productive and reproductive traits is recommended before revision of the classification methodology.
Genotype by environment interaction for milk yield in Sarda dairy sheep
Authors: SANNA S. R. , CARTA A. , CASU S.
Published: March 2003

Genotype by environment interaction (GEI) for milk yield (ME) wasinvestigated by analyzing 40 140 first lactation records performed in 538 flocks. Flock–year effects from national genetic evaluation were used to define low (L), medium (M) and high (H) yielding environments. Differences observed between adjacent subsets were approximately 20% of the trait overall mean. Sire variance components estimated using multitrait analysis were 58, 82 and 149% of the estimate from the complete dataset (L, M and H, respectively) and genetic correlation coefficient between extreme subsets was 0.66, lower than genetic correlations obtained from randomly sampled subsets. Rank correlation coefficients between estimated transmitting abilities (ETA), obtained independently within L, M and H subsets for 71 AI rams having at least 10 daughters per subset, were lower than one (ranging from 0.42 to 0.56). These results strongly supported the existence of GEI for milk yield in Sarda sheep flocks. The influence of GEI on phenotypic responses in flocks differing in yield level could be due to a reduced expression of genes under conditions of restricted environmental opportunity. Splitting the selection scheme according to farming conditions does not seem a suitable solution for the Sarda breeding program. Thus, to provide farmers with genotypes suitable to exhibit a good phenotypic expression in different conditions, the selection across all environments, in which the descendants are expected to perform, still seems the best option.
Hormonal calcium regulation and calcium setpoint in offspring of bitches with different calcium intakes during pregnancy
Authors: Schoenmakers I. , Mol J. A. , Hazewinkel H. A. W.
Published: March 2003

High maternal calcium (Ca) intake may lead to alterations in development and differentiation of fetal tissues and may result in altered ‘programming’ of Ca homeostasis, with eventual effects on Ca handling and skeletal development in the offspring during later life. In bitches fed a diet with a Ca intake three times above recommendations (3.27 g/100 g vs 1.14 g/100 g dry matter) during the second half of pregnancy, the plasma concentration of 1,25 dihydroxy cholecalciferol (1,25 (OH)2 vit D) appeared to decrease, while plasma Ca, phosphorus (P), parathyroid hormone (PTH) and calcitonin (CT) concentrations remained unchanged. High maternal Ca intake did not result in altered basal or stimulated plasma concentrations of Ca, P, PTH, CT and 1,25 (OH)2 vit D in the offspring (n = 7) when compared with pups from bitches fed a normal Ca diet during the entire pregnancy (controls, n = 7). The Ca setpoint for PTH secretion (Ca Sfor PTH) was therefore not different from controls. From this pilot study it may be concluded that excessive Ca intake during late pregnancy in the bitch has no deleterious effects on hormonal Ca homeostasis in the offspring.
Effects of dietary Ca/P ratio, P level and microbial phytase supplementation on nutrient digestibilities in growing pigs: precaecal, post‐ileal and total tract disappearances of OM,
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 precaecal, post‐ileal and total tract disappearances of organic matter (OM), phosphorus (P) and calcium (Ca). In experiment 1, two Ca/P ratios and two P levels were tested according to a 2 × 2 factorial arrangement within a Latin square design. In experiment 2, the diets of experiment 1 were supplemented with phytase (500 FTU/kg). There was a substantial absorption of OM, P and Ca in the post‐ileal tract for all diets. Precaecal and total tract disappearances of OM were reduced by phytase addition (−4.4 and −0.8%, respectively). Supplementation with phytase resulted in an improvement of total tract and post‐ileal P disappearances by 10.3 and 12.1%, respectively, without affecting precaecal P disappearance. Addition of feed phosphate resulted in a higher precaecal disappearance of P (+10.8%), resulting in a higher total tract disappearance of P (+5.9%). Addition of limestone had little effect on disappearances of OM, P and Ca, but reduced activity of supplemental phytase and had a negative influence on growth performance. Precaecal, post‐ileal and total tract Ca disappearances were hardly affected by the examined dietary factors. The results might indicate that P from feed phosphate is absorbed primarily prececally and that P from phytate, liberated by microbial phytases, is dominantly absorbed post‐illeally.
Effects of a lactoperoxidase system and lactoferrin, added to a milk replacer diet, on severity of diarrhoea, intestinal morphology and microbiology of digesta and faeces in young calves
Authors: Van Leeuwen P. , Oosting S. J. , Mouwen J. M. V. M. , Verstegen M. W. A.
Published: March 2003

The objective of the present study was to determine the effects of the combination of a lactoperoxidase system (LP‐s) and lactoferrin (LF) added to a milk replacer diet on severity of diarrhoea, the morphology of the small intestinal mucosa, and the microbiology of digesta and faeces in young calves, in comparison with a control diet. The experiment was conducted with 30 young calves, 15 per treatment, during the period of 7–21 days of age. During this period, calves are sensitive to gastrointestinal disturbances that can cause diarrhoea. The results showed a significantly (p < 0.05) reduced severity of diarrhoea in the LP‐s/LF group compared to the control group as assessed by faecal consistency scores. Numbers of CFU (colony forming units) of Escherichia coli in jejunal and colonic digesta and in faeces were lower in the LP‐s/LF group compared with the control group. The differences were significant in both colonic digesta (p < 0.1) and in faeces (p < 0.05). Examination of the small intestinal mucosa, using a dissecting microscope, indicated more finger shaped villi in the distal jejunum of LP‐s/LF‐treated calves compared with the control group (p < 0.05). Histometrical measurements showed that these villi were significantly (p < 0.05) longer.
Breed differences and genetic parameters for melting point, marbling score and fatty acid composition of lot‐fed cattle
Authors: Malau‐Aduli A.E.O. , Edriss M. A. , Siebert B. D. , Bottema C. D. K. , Pitchford W. S.
Published: March 2003

Fatty acid composition, marbling score and melting point data collected between 1994 and 1996 were analysed. The data were from the adipose tissue of 764 Angus, Belgian Blue, Hereford, Jersey, Limousin, South Devon and Wagyu crossbred cattle slaughtered after lot‐feeding at 500 days of age. The aim was to investigate sire‐breed differences and to estimate heritability and genetic and phenotypic correlations. Significant breed differences were found: Jersey crosses had the highest marbling score and Belgian Blue crosses had the lowest. Limousin crosses had the highest melting point and Jersey crosses the lowest. South Devon crosses had the highest proportion of stearate and Jersey crosses the lowest. Desaturation indices in C16 and C18 fatty acids were highest in Jersey crosses and lowest in Limousin and South Devon crosses. In contrast, there were no breed differences in the proportions of palmitate, oleate, total saturated, total mono‐unsaturated fatty acids and elongation index. Heritability estimates of individual fatty acids and their summations, melting point and marbling were low to moderately low (0.05–0.27). Strong genetic correlations of melting point and desaturation index in C16 fatty acids (‐0.93), melting point and stearate (0.62), marbling and stearate (‐0.71) and marbling and desaturation index in C18 fatty acids (0.62) were observed. Phenotypic correlation were generally low. The results imply that fatty acids in the adipose tissue of lot‐fed cattle have a moderately low heritability, hence genetic progress might be slow.
Metabolites of Monascus ruber in silages
Authors: Schneweis I. , Meyer K. , Hörmansdorfer S. , Bauer J.
Published: March 2003

A total of 233 silages were examined and found that Monascus ruber was present in 43 samples with counts between 1 × 103 and 9 × 106 colony‐forming units (CFU)/g (mean: 2 × 105 CFU/g). Monacolin KL and the hydroxy acid monacolin KA were detected by liquid chromatography‐mass spectrometry in 45 and 50 of 233 samples at levels ranging from 25–15 600 and 28–65 400 μg/kg, respectively. Citrinin was found with high‐performance liquid chromatography‐fluorescence detection (FLD) in 14 (6%) samples, the concentrations varied between 2.4 and 64.2 μg/kg. The concentrations of citrinin were low and toxic effects are not anticipated. Monacolin KA and monacolin KL occur frequently and in considerable amounts in silages. These metabolites are believed to influence the metabolic activity of rumen anaerobic fungi resulting in a poorer digestion of crude fibre.
Effect of cellulose on the digestibility of high starch versus high fat diets in dogs
Authors: Kienzle E. , Dobenecker B. , Eber S.
Published: March 2003

The effects of cellulose added in three levels (7, 15 and 20% crude fibre in dry matter) to three different basal diets (a high fat diet, a high starch diet with raw starch and a high starch diet with cooked starch) on apparent digestibility were investigated in eight adult dogs. Cellulose had little effect on the apparent digestibility of fat. In the high fat diet there was no significant decrease, not even at the highest cellulose level (98.3% compared with 98.1% in the basal high fat diet). In the cooked starch diets, fat digestibility decreased from 95.1% in the basal cooked starch diet to 93.8% at the highest cellulose level. In the raw starch diets, digestibility did not decrease with increasing cellulose levels. The apparent digestibility of crude protein was considerably decreased by cellulose in all diets. Starch also decreased protein digestibility and the effects of cellulose and starch appeared to be additive (high fat diet decrease of protein digestibility from 86.7 to 83.5%, cooked starch from 81.6 to 78.6%, raw starch from 79.0 to 70.8%, basal diets to highest cellulose levels, respectively). The apparent digestibility of nitrogen‐free extract decreased from 93.9% in the basal cooked starch diet to 84.5% at the highest cellulose level. The figures for the raw starch diets were similar (decrease from 93.4 to 85.9%). Cellulose decreased the apparent digestibility of energy in all diets. This decrease was more marked in the high starch diets (cooked starch decrease from 89.1 to 69.6%, raw starch from 88.9 to 70.2%) than in the high fat diet (decrease from 90.1 to 76.1%). An evaluation of previous data showed that in general fibre has a higher impact on the apparent digestibility of energy in high carbohydrate diets than in low carbohydrate diets. The apparent digestibility of potassium, sodium and chloride was impaired by cellulose. The apparent digestibility of these minerals tended to be lower in the high starch diets, especially in the raw starch diet, and the effect of cellulose was usually more marked in those diets.
Hydrolysis of phytic acid by intrinsic plant or supplemented microbial phytase (Aspergillus niger) in the stomach and small intestine of minipigs fitted with re‐entrant cannulas
Authors: Rapp C. , Lantzsch H.‐J. , Drochner W.
Published: March 2003

Hydrolysis of phytate in the stomach and the small intestine as influenced by intrinsic plant (wheat) and supplemented microbial phytase (A. niger) were investigated with six minipigs (40–50 kg initial BW) fitted with re‐entrant‐cannulas in the duodenum, 30 cm posterior to the pylorus (animals 1, 4, 5, and 6) and ileocecal re‐entrant cannulas, 5 cm prior the ileocecal junction (animals 1, 2, and 3), respectively. Dietary treatments were as follows: (1) diet 1, a corn‐based diet (43 U Phytase/kg DM); (2) diet 2, diet 1 supplemented with microbial phytase (818 U/kg DM) and (3) diet 3, a wheat‐based diet (1192 U/kg DM). At 0730 and 1930 per animal 350 g diet mixed with 1050 ml de‐ionized water were fed. Digesta were collected continuously and completely during 12 h after feeding.

Duodenal recovery of dry matter and total phosphorus were 100% in the period between two feedings, irrespective of dietary treatment. In animals fed the wheat‐based diet, dry matter left the stomach faster (p < 0.05) during the first hour after feeding than in animals fed the corn‐based diets (41.3 vs. 31.0 and 25.8% of intake, respectively). Supplemented microbial phytase did not affect ileal dry matter digestibility of the corn‐based diet.

In the first hour after feeding, phosphorus concentration of the duodenal digesta of animals fed corn‐based diets with or without supplemented microbial phytase (5.86, 6.19 mg total P/g DM) exceeded the dietary level considerably (4.30 and 4.21 mg total P/g DM) indicating a higher solubility of corn than wheat phosphorus in the stomach. Apparent ileal P absorption was higher (p < 0.05) in the wheat‐based diet (37.6%) and corn‐based diet supplemented with microbial phytase (34.3%) than in the unsupplemented corn‐based diet (17.6%).
Influence of dietary ß‐glucan on growth performance, lymphocyte proliferation, specific immune response and haptoglobin plasma concentrations in pigs
Authors: Hiss S. , Sauerwein H.
Published: March 2003

Immunomodulatory feed additives might offer alternatives to anti‐microbial growth promoters in swine production. The present study was conducted to assess the effects of β‐1,3/1,6 glucans, i.e. of specific yeast cell wall components, on immune function and growth performance in pigs. After weaning at 4 weeks of age, 75 piglets were allocated to 3 different groups for 4 weeks, the diet was supplemented with 0, 0.015 or 0.03% of β‐glucan, respectively. All animals were vaccinated against porcine reproductive and respiratory syndrome (PRRS). After 4 weeks, average daily gains (ADG) of β‐glucan treated pigs were not different from the controls. Feed intake was tendentiously (p < 0.1) increased at 0.03%β‐glucan, without alteration of feed efficiency. Serum haptoglobin concentrations at the end of the 4 week treatment were increased in all groups when compared to the initial levels (p < 0.001), without differences between the groups (p > 0.05). Haptoglobin levels were inversely related to ADG. Lymphocyte proliferation indices were not different in control and treatment groups. Specific vaccination responses, as quantified by the PRRS antibody titres occurred in all animals, but no relation with β‐glucan feeding was observed. Our results indicate marginal benefits of β‐glucan supplements for growth performance and no effect on the immune parameters tested. The observed trend towards increased feed intake needs further elucidation.
Efficiency of amino acid utilization in the growing pig at suboptimal levels of intake: branched‐chain amino acids, histidine and phenylalanine + tyrosine
Authors: Heger J. , Van Phung T. , Křížová L. , Šustala M. , Šimeček K.
Published: March 2003

Five balance experiments on growing pigs were carried out to study the marginal efficiency of utilization of isoleucine, leucine, valine, histidine and phenylalanine + tyrosine and to estimate their requirements for maintenance. Purified diets based on casein and crystalline amino acids as the sole source of N contained graded levels of each amino acid, corresponding to protein accretion rates of 0, 33, 66, 99 and 132 g/day, respectively. All other essential amino acids were given in a 30% excess. N retention increased linearly (p < 0.01) as the dietary concentration of the limiting amino acid increased. Based on linear regression equations relating amino acid deposition in body protein to amino acid intake, marginal efficiencies of ileal digestible amino acid utilization were calculated to be isoleucine – 0.81, leucine – 0.81, valine – 0.82, histidine – 1.17 and phenylalanine + tyrosine – 0.67. Extrapolating the regression equations to zero N retention, the daily requirements of amino acids for N equilibrium were estimated to be (mg/kg0.75) isoleucine – 18, leucine – 33, valine – 23, histidine – 14 and phenylalanine + tyrosine – 43.
A survey of insects attacking seed cones of Pinus cembra in the Alps, the Pyrénées and Massif Central
Authors: Dormont L. , Roques A.
Published: March 2003

The composition and impact of the entomofauna exploiting seed cones of Swiss stone pine (Pinus cembra L.) was surveyed in native stands and plantations of France, Italy, Switzerland and Austria during 1992–1996. A total of 2785 cones were collected from 25 sites. The cone entomofauna consisted of five species, of which three (Dioryctria abietella, Eupithecia abietaria, Cecidomyia pini) were regularly observed. The two other insects, Polydrusus atomarius and Zeiraphera diniana were observed on first‐year cones, and only in two stands. No spermatophagous insect was detected. None of these insect species could be considered specific to cones of P. cembra. The overall damage never exceeded 40% of the cone crop. The importance of cone damage varied with year, cone abundance, and the position of the tree in the stand. The cone entomofauna of Swiss stone pine largely deviated from that recorded in cones of other high altitude conifers but resembled that of other stone pines growing in Eurasia. The question: why cones of P. cembra were less damaged by insects than those of other alpine conifers is discussed.
Side‐effect of integrated pest management and conventional spraying on the composition of epigeic spiders and harvestmen in an apple orchard (Araneae, Opiliones)
Authors: Pekár S.
Published: March 2003

The effect of two different integrated pest management (IPM) practices and conventional spraying (CHEM) on the composition of epigeic spiders and harvestmen in an apple orchard was investigated over 4 years. Conventional spraying included more frequent and nonselective pesticide applications, whilst IPM plots were treated with selective pesticides and less frequently. One of the IPM plots was undersown with various plantings, the other with grass, and the plot under conventional spraying was covered with weeds. In total, eight species of harvestmen and 65 species of spiders were recorded whose abundance peaked in spring and autumn. Arachnids were on average over the 4 years less abundant on both IPM plots than on CHEM which seems to be due to lower plant density of weed cover. Seasonal oscillations were only slightly different in particular seasons between plots, in particular during spraying. In 1992 the arachnids were a little more abundant on the conventional spraying plot, in 1993 on IPM plots and during subsequent 2 years the difference diminished. The seasonal abundance appeared to be influenced by herbicide applications. Species diversity of all plots were higher than in crop fields, but did not reveal disagreement between plots. The numerical hierarchical classification (TWINSPAN) detected that the composition of arachnids was influenced in particular by annual variation. The arachnid assemblages of the studied plots were not found to be markedly different during the whole study. The effect of IPM practices and conventional spraying on the composition of epigeic arachnids was far less apparent than it was in arboreal species. However, nearly 20% of spiders were found common with crown stratum. Some of them occupied both strata, a few occurred in epigeon only accidently, while others moved vertically during the season. Thus the epigeic fauna seems to support arboreal spiders.
Evaluation of tolerance in Chrysoperla carnea Steph. (Neuropt., Chrysopidae) to successive insecticidal treatments
Authors: Zaki F. N. , Farag N. A. , Shadia E. Abdel‐Aziz
Published: March 2003

The results obtained indicate that the Chrysoperia carnea collected from Giza region (where no insecticidal treatments were used), were more sensitive to malathion than those of Kafr El‐Sheikh, where insecticides were used intensively. In predator colonies which were treated repeatedly with malathion, the sensitivity to malathion decreased from the first to the fifth generation. On the other hand, insects of the reference colony, showed a considerable increase in sensitivity within the same generations.
Prey preferences of six species of Carabidae (Coleoptera) and one Lycosidae (Araneae) commonly found in UK arable crop fields
Authors: Kielty J. P. , Allen‐Williams L. J. , Underwood N.
Published: March 2003

Abstract: Laboratory experiments were used to determine the feeding preferences of six carabid beetles and one lycosid spider on aphid and collembolan prey. The first investigation used only five species of carabid Pterostichus melanarius Illiger, Pterostichus madidus F., Harpalus rufipes DeGeer, Nebria brevicollis F. and Carabus violaceus L., which had been caught most commonly in pitfall traps in the headland region of arable crop fields. When offered Brevicoryne brassicae L., Sitobion avenae F., Metopolophium dirhodum Walker and Rhopalosiphum padi L. as prey items, the species consistently consumed in high numbers was M. dirhodum. In subsequent experiments four carabids Pterostichus cupreus L., P. melanarius, P. madidus. H. rufipes and a lycosid spider Trochosa ruricola DeGeer whose distribution was shown by pitfall trapping to extend throughout the arable crop, were the chosen predators. These predators were offered a choice between M. dirhodum and entomobryid collembolans (a recognised alternative prey item) to gauge their preference between the two prey types. Both male and female P. cupreus and P. melanarius showed a significant preference for the aphid prey, while there was no significant preference displayed by the other species. The effect of temperature on the voracity of these five predators fed on M. dirhodum was investigated. There were significant differences in the number of aphids consumed by the species and sexes at the different temperatures. Regression analysis on the mean numbers of aphids eaten by each sex of the five predators, showed that in the majority of cases there was a significant increase in predation with increasing temperature. In considering the dietary preferences illustrated by these experiments, it appeared that P. cupreus and P. melanarius offered the greatest potential in controlling aphids on arable crops.
Altitudinal variation in foliar chemistry and anatomy of yunnan pine, Pinus yunnanensis, and pine sawfly (Hym., Diprionidae) performance
Authors: Hengxiao G. , McMillin J. D. , Wagner M. R. , Zhou J. , Zhou Z. , Xu X.
Published: March 2003

Host plant characteristics associated with the larval feeding performance of a pine sawfly were examined across an altitudinal gradient in south‐western China. Neodiprion xiangyunicus (Xiao and Huang) larval performance (e.g. larval mass and potential fecundity) and defoliation intensity increased at higher altitudes along an altitudinal gradient in Sichuan, China. Needle chemistry and anatomy of yunnan pine, Pinus yunnanensis (Franch.), also varied across along an altitudinal gradient. In general, total sesquiterpene levels decreased with increasing altitude, oxygenated monoterpenes increased with increasing altitude, and total monoterpenes did not vary significantly across the altitudes. Concentrations for 16 of the 28 individual terpenes varied significantly between at least two of the three altitudes; the vast majority (75%) of these differences were for sesquiterpenes. Foliar nutrition, morphology and anatomy also varied by altitude. Foliar nitrogen and needle dry biomass were significantly lower in trees at the high altitude site. Needle epidermal thickness and diameters of resin ducts were significantly thicker and wider, respectively, in trees at the middle altitude than at the top and bottom altitudes. These results suggest that a combination of foliage chemistry and morphology rather than any single plant trait probably determines the observed patterns of insect herbivory.
Effect of biological and chemical insecticides on Spodoptera species (Lep., Noctuidae) and marketable yields of tomatoes
Authors: Liburd O. E. , Funderburk J. E. , Olson S. M.
Published: March 2003

Various biological and chemical insecticide treatments were evaluated against beet armyworm Spodoptera exigua (Hübner), yellowstriped armyworm Spodoptera ornithogalli (Guenée) and southern armyworm Spodoptera eridania (Cramer) to determine their effects on Spodoptera species, fruit quality and marketable yields of tomatoes Lycopersicon esculentum Mill. Biological insecticides included several Bacillus thuringiensis (Berliner) products including Condor® OF, Dipel® 2X, Javelin® WG, Bactec® III, Biobit® FC, Cutlass® WP and Lepinox® G. Other biological treatments included a baculovirus, SeNPV isolated from S. exigma, and an entomophagous nematode, Steinernema carpocapsae Weiser. Chemical treatments consisted of several insecticides from various classes including a carbamate (methomyl), pyrethroid (fenpropathrin) and an organophosphate (chlorpyrifos). A natural extract from the neem tree azadirachtin and an untreated control were also included in the evaluation studies. Population densities of S. exigua were below the economic threshold level in control plots and there were no significant differences for small, medium and large larvae. Densities of S. ornithogalli and S. eridania larvae exceeded the threshold level and significant treatment differences were observed in their populations. Fruit injuries were significantly higher in nonefficacious treatments that included S. carpocapsae, SeNPVs and untreated controls. Average weight per fruit was not significantly affected by treatment rates of applications, but total marketable yields were significantly higher in efficacious biological, chemical and combination treatments compared with the control.
Flower visitation and oviposition behavior of Frankliniella occidentalis (Tysan., Thripidae) on cucumber plants
Authors: Kiers E. , De Kogel W. J. , Balkema‐Boomstra A. , Mollema C.
Published: March 2003

Oviposition behaviour of western flower thrips, Frankliniella occidentalis(Pergande) on greenhouse cucumber, Cucumis satifus(L.) was investigated. Most eggs were laid in the leaves, along veins and under leaf hairs, with only a few on plant stems and flowers. Oviposition rate was higher during the day than during the night. During the day, more adult thrips were found in the flowers than during the night. The number of adult thrips per flower increased rapidly after sunrise with the highest densities occurring around noon and thereafter the number of thrips in flowers decreased during the afternoon. No differences were found in the number of larvae (first and second instars) in flowers during the same period. The number of adult thrips on male and female cucumber flowers was not different, indicating that pollen is not the only attraction in flowers for thrips.
New aspects of the biology of the Melanesian rfhinoceros beetle Scapanes australis (Col., Dynastidae) and evidence for field attraction to males
Authors: Prior R. , Morin J.‐P. , Rochat D. , Beaudoin‐Ollivier L. , Stathers T. , Kakul T. , Embupa S. , Nanguai R.
Published: March 2003

Scapanes australis is a major coconut pest, endemic in Papua New Guinea. Early in the night, males placed singly into artificial galleries made in young coconut palms exhibited a sex specific calling behaviour for 1 to 1.5 h. Coming to the gallery entrance, they raised the abdomen and the hind legs, the head lowered inside the gallery, and emitted a liquid secretion, rhytmically smeared by crossing the legs. Females which did not behave so, were very mobile. The adult flying period coincided with the male calling behaviour. In field assays with caged insects on coconut palms, attraction of both sexes to males was evidenced when they were calling. Males fought for gallery possession at a male arrival. No aggression but mating was observed with arriving females, which proved not to have developed oocytes. The strong male attractionwas confirmed using automatic traps, baited with one lived male in a sugarcane piece. Male were assumed to release an aggregation pheromone. Further studies are underway to identify the putative pheromone.
Comparison of a Canadian and a Dutch strain of the parasitoid Aphelinus mali (Hald) (Hym., Aphelinidae) for control of woolly apple aphid Eriosoma lanigerum (Haussmann) (Hom., Aphididae) in the Netherlands: a simulation approach
Authors: Mols  , Boers
Published: March 2003

Woolly apple aphid, Eriosoma lanigerum is one of the important apple pests in the Netherlands. Weather conditions and natural enemies determine whether woolly apple aphid (WAA) will reach pest status. WAA may escape control by natural enemies and therefore it must be controlled using chemical insecticides. To prevent unnecessary applications of insecticides and to promote biological and natural control of WAA more knowledge is needed about the role of natural enemies, weather and their effects on the development of WAA populations. The monophagous parasitoid Aphelinus mali (Hald.) has been introduced into most of apple growing areas to control WAA, but success is variable and depends on climatological conditions. In the Netherlands the level of parasitization is often too low, especially after warm winters. The biological control potential of a strain of A. mali from Nova Scotia (Canada) was compared with a Dutch strain by simulating population growth of both WAA and the Dutch and Canadian strain of the parasitoid for three different years The results indicate that the Canadian strain would perform in general better than the Dutch strain under Dutch weather conditions.
Evaluation of green lacewings, Chrysoperla plorabunda (Fitch) (Neurop., Chrysopidae), for augmentative release against Toxoptera citricida (Hom., Aphididae) in citrus
Authors: Michaud J. P.
Published: March 2003

Larvae of the lacewing Chrysoperla plorabunda (Fitch) were evaluated in laboratory and field tests for potential to control the brown citrus aphid, Toxoptera citricida (Kirkaldy) in inundative releases. Larvae surviving to pupation consumed an average of 1676, 1297, 392, 165 and 130 1st–4th instar T. citricida nymphs and apterous adults, respectively, and the mean developmental time was 27.0, 23.0, 16.5, 13.8 and 18.3 days, respectively. The average pupation rate was 37.5%, but only 6.3% of pupae yielded adults. Developmental time and survival to pupation varied with the life stage of aphids fed to larvae, 4th instars yielding the highest survival and shortest developmental time. Development of C. plorabunda was compared on diets of T. citricida and Aphis spiraecola. Only 6.3% of larvae completed development on T. citricida, whereas 37.5% yielded adults on A. spiraecola. Larvae consumed more of the brown T. citricida than the green A. spiraecola in a choice test on a white background, but no preference was evident when aphids were offered on a black background. Two separate field trials were performed in citrus groves with T. citricida infestations in which an average of 275 and 116 C. plorabunda larvae/tree were released, respectively. The rate of T. citricida colony maturation (= survival to alate production) was very low in the first trial, and relatively high in the second trial, but did not differ between control and release trees in either trial. The most apparent cause of aphid colony mortality was predation by the coccinellids Cycloneda sanguinea L. and Harmonia axyridis Pallas. Despite acceptance of T. citricida in the laboratory, very few C. plorabunda larvae were observed feeding on aphid colonies on release trees.
Susceptibility of Tuta absoluta (Meyrick) (Lep., Gelechiidae) reared on two species of Lycopersicon to Bacillus thuringiensis var. kurstaki
Authors: Giustolin T. A. , Vendramim J. D. , Alves S. B. , Vieira S. A. , Pereira R. M.
Published: March 2003

The mortality of Tuta absoluta (Meyrick) larvae that were fed on leaves of Lycopersicon hirsutum f. glabratum (PI 134417, insect resistant) and Lycopersicon esculentum (cultivar Santa Clara, susceptible) treated with Bacillus thuringiensis var. kurstaki (Btk) was evaluated. Feeding on untreated PI 134417 was detrimental to the survival of T. absoluta larvae. When Btk was applied to the two Lycopersicon plants, mortality occurred in all T. absoluta instars. Application of Btk on tomato leaves had synergistic or additive effects with the resistant genotype on larval survival. This effect was dependent on the instar at which the larvae were fed Btk‐treated leaves. Delayed Btk application may cause higher insect mortality if the insects become more susceptible to the pathogen after a longer period of feeding on the resistant crop.
Host preference and sex allocation of three hymenopteran parasitoid species (Ichneumonidae and Braconidae) of a longicorn pest, Oemona hirta (Fabr.) (Col., Cerambycidae)
Authors: Wang Q. , Shi G.
Published: March 2003

The host preference and sex allocation of two ichneumond parasitoids, Xanthocryptus novozealandicus (Dalla Torre) and Campoplex sp., and one braconid parasitoid, Apsicolpus hudsoni Turner of the longicorn borer, Oemona hirta, were studied in New Zealand. The size of the borer larvae attacked by the parasitoids can be determined by measuring the gallery width of the borers. These parasitoids are idiobionts and their secondary sex ratio is female‐biased. Females of these species are significantly larger than males, and the females allocate the sex of offspring depending on the size of host larvae, by laying female‐producing eggs on significantly larger host larvae. Xanthocryptus novozealandicus is larger in body size and shorter in ovipositor length than Campoplex sp. and A. hudsoni, and consumes late instar larvae or prepupae in shallow galleries whereas the latter two utilize early to middle instar larvae in deep galleries. Campoplex sp. and A. hudsoni preferred host larvae in significantly larger tree twigs than X. novozealandicus.
The effect of wheat α‐amylase inhibitors incorporated into wheat‐based artificial diets on development of Sitophilus granarius L., Tribolium confusum Duv., and Ephestia kuehniella Zell
Authors: Warchalewski J. R. , Gralik J. , Winiecki Z. , Nawrot J. , Piasecka‐Kwiatkowska D.
Published: March 2003

Artificial grain kernels made from ground wheat grain, commercial wheat starch and wheat proteinaceous α‐amylase inhibitors were used as diets for adults of the granary weevil (Sitophilus granarius L). For the confused flour beetle (Tribolium confusum Duv.) and the Mediterranean flour moth (Ephesitia kuehniella Zell.), a friable mixture of the diets was used. The results of feeding trials showed that the survival of S. granarius adults was not correlated with the soluble proteins extracted from wheat and amylolytic activity located in this protein fraction. On the other hand, the weight of dust (the index of feeding intensity) produced during feeding depended on the presence of α‐amylase and trypsin inhibitors in wheat‐based diets. Ephesitia kuehniella larvae did not develop at all on a diet consisting of 50% wheat starch and 50% crude α‐amylase inhibitors from wheat. The same diet lengthened the development time of T. confusum larvae by 15.1 days. These results attest to the existence of a specific native enzymatic apparatus in the alimentary canals of these three grain pests. However, the highly active insect α‐amylase inhibitors appear to have a limited influence on the developmental parameters studied although some reduction of insects populations might be expected.
Shoot feeding ecology of Tomicus piniperda and T. minor (Col., Scolytidae) in southern China
Authors: Långström B. , Lisha L. , Hongpin L. , Peng C. , Haoran L. , Hellqvist C. , Lieutier F.
Published: March 2003

Abstract: The pine shoot beetle, Tomicus piniperda, is causing substantial tree mortality to Pinus yunnanensis in south‐western China, whereas the same species in Europe seldom kills Pinus sylvestris. In order to understand this difference in aggressiveness, we studied the shoot feeding ecology of the pine shoot beetles in Yunnan, and compared it with European results. We found many similarities in the shoot feeding behaviour of T. piniperda, and also that of Tomicus minor, which was common locally. In contrast to Europe, however, the pine shoot beetles in Yunnan seem to be able to predispose the host trees for stem attack by intensive shoot‐feeding. It has also been observed that beetles aggregate in certain trees during shoot feeding, but we could not verify that in our experiment.
A Model Integrating Components of Rate‐reducing Resistance to Cercospora Leaf Spot in Sugar Beet
Authors: Rossi V. , Giosue S. , Racca P.
Published: March 2003

Four components of rate‐reducing resistance to Cercospora leaf spot in sugar beet (infection efficiency of conidia RC1, incubation period RC2, size of necrotic spots RC3 and spore yield RC4), previously measured in single infection cycle experiments, were integrated into a model simulating the chain of infection cycles under field conditions, as influenced by weather. To integrate resistance components, variables accounting for infection frequency, incubation period, affected leaf area, and infectiousness – which are computed for a susceptible cultivar – were modified by means of coefficients which reduced (RC1, RC3, RC4) or increased (RC2) them. Outputs obtained by running the model and changing resistance components actually reduced the rate of disease progress and the area under the disease progress curve of epidemics (AUDPC), as happens at field level; therefore, the approach may be considered successful. Changes in single resistance components were closely correlated with changes in AUDPC: improvements in RC1, RC3 or RC4 reduced AUDPC by the same, over the whole range of variation in infection frequency, affected leaf area, and infectiousness; on the contrary, little improvements in RC2 were more effective than stronger ones. When components acted simultaneously, each of them reduced disease progress in proportion to its magnitude; when all components were improved by the same amount, they had about the same effectiveness in slowing the epidemic. Changing more components simultaneously reduced the disease development slightly more than additively. Advantages for plant breeders in improving their selection strategies are outlined.