bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of maize plants on colonisation of cowpea plants by bean flower thrips, Megalurothrips sjostedti
Authors: Kyamanywa S. , Baliddawa C. W. , Ampofo K. J. O. 
Published: April 2011

AbstractThe effect of non‐host maize plants on colonisation of cowpea by Megalurothrips sjostedti (Trybom) (Thysanoptera; Thripidae) was investigated.There were no differences in population density and activity of M. sjostedti on sole cowpea crop and mixed cowpea/maize crop during the colonisation phase (i.e. 10–30 days after emergence of the plants. However, subsequently M. sjostedti numbers were lower in the mixed than in the sole crop, suggesting that maize did not interfere with colonisation of cowpea crop by thrips. In a choice situation, higher numbers of M. sjostedti oriented towards, and settled on, sole cowpea plants than on those mixed with maize. Olfactory tests indicated that fewer thrips oriented towards a cowpea/maize mixed odour source. When equal numbers of thrips were introduced into the centre of sole‐ and mixed‐cropped cowpea plots, the thrips became randomly distributed in each plot. Fewer thrips were recovered from the mixture than from the sole crop.It is concluded that, although non‐host plant odours do not reduce thrips colonisation they interfere with host plant utilisation.
Host‐feeding and egg maturation by Pachycrepoideus vindemiae
Authors: Phillips D. S. 
Published: April 2011

AbstractPachycrepoideus vindemiae Rondani (Hymenoptera: Pteromalidae) is a facultative hyperparasitoid of Drosophila parasitoids in Europe. Female P. vindemiae host‐feed from the same hosts into which they lay eggs and this enables them to mature additional eggs. P. vindemiae females were allowed to host‐feed from puparia containing Drosophila melanogaster Meigen (Diptera: Drosophilidae) pupae or pupae of Asobara tabida Nees (Hymenoptera: Braconidae). Wasps which had host‐fed carried significantly more eggs; the species of host which was fed from had no significant effect on the number of mature eggs in the ovaries. Host‐feeding caused no significant reduction in the size of the emerging offspring. P. vindemiae were allowed to forage over patches containing different frequencies of the two host species. No significant oviposition preference was found but there were marked host‐feeding preferences which were affected by the age of the host pupae. It is suggested that these preferences were due to the physical nature of the hosts which were fed from.
Temperature requirements of four parasites of the Russian wheat aphid Diuraphis noxia
Authors: Bernal Julio , González D. 
Published: April 2011

AbstractWe studied the effects of six constant temperatures (7.2, 10.0, 15.5, 21.1, 26.6, and 29.4 °C) on developmental rates and developmental times in four parasites of Diuraphis noxia (Mordwilko) (Homoptera: Aphididae): Aphelinus asychis Walker from Chile, A. asychis W. from France, Aphidius matricariae Haliday from Iraq, and Diaeretiella rapae (M'Intosh) from Pakistan. Differences were not detected in developmental time between sexes in D. rapae at any of the temperatures tested. Males developed faster than females in A. matricariae at 10 and 21.1 °C, A. asychis Chile at 15.5 and 29.4 °C, and A. asychis France at 10, 15.5, and 21.1 °C (P<0.05). Developmental thresholds (t), and times‐to‐adult in degree‐days (K) of the four parasites are: 7.1 °C and 248.8 for A. asychis Chile, 6.4 °C and 246.7 for A. asychis France, 1.4 °C and 311.4 for A. matricariae, and 2.1 °C and 293.4 for D. rapae, respectively. Based on the predicted accumulation of degree‐days and number of generations per year for the four parasites at three climatically distinct localities in California, we concluded that the parasite with the lowest developmental threshold (A. matricariae) may complete ca. 4.5, 3.6, and 2.1 more generations than the parasite with the highest developmental threshold (A. asychis from Chile) at the coldest, intermediate, and warmest localities, respectively. It was suggested that parasites with lower developmental thresholds, despite their generally greater time‐to‐adult, will have greater population densities following the winter season than parasites with higher developmental thresholds, they may appear earlier and thus have greater potential as effective biological control agents especially in annual crops such as small grains. When attempting to introduce parasites for biological control of a target host the developmental thresholds of both the parasite and the host should be considered in conjunction with other attributes such as searching efficiency, fecundity, host preference, and others.
Genetic variation in sex allocation in a parasitic wasp: variation in sex pattern within sequences of oviposition
Authors: Wajnberg Eric 
Published: April 2011

AbstractIn order to maximize their fitness under Local Mate Competition (LMC), arrhenotokous female wasps have to produce a precise sex ratio when encountering hosts. Recent progress in the theory of hymenopterous parasitoid reproduction suggest that they manage to do it by laying male and female eggs in a particular order and that such reproductive strategies are adaptive. Therefore, the determinism of such sequential patterns would be regulated by genetic control on which natural selection could act. To test this hypothesis, sequences of oviposition were recorded in a set of Trichogramma brassicae Bezdenko (Hymenoptera; Trichogrammatidae) females and in their daughters by providing them Ephestia kuehniella Zeller (Lepidoptera; Pyralidae) eggs.In order to describe accurately sex pattern within these oviposition sequences, I present a joined non‐parametric and multivariate statistical method. It is shown that T. brassicae females do not produce male and female eggs in random sequences. Moreover, the way they organize the sequence of the sexes in their progeny seems to be under a strong genetic control. The evolutionary consequences of such results are discussed.
Encarsia formosa parasitizing the Poinsettia‐strain of the cotton whitefly, Bemisia tabaci, on Poinsettia: bionomics in relation to temperature
Authors: Enkegaard Annie 
Published: April 2011

AbstractAdult longevity, developmental time and juvenile mortality of Encarsia formosa Gahan (Hymenoptera: Aphelinidae) parasitizing the Poinsettia‐strain of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) on Poinsettia (Euphorbia pulcherrima Willd.) were investigated in laboratory experiments at three temperatures: 16 °C, 22 °C and 28 °C. Furthermore, the parasitoid's preference for different larval stages of the whitefly was determined at 24.5 °C.The lifespan of E. formosa decreased with temperature from one month at 16 °C to nine days at 28 °C. A lower temperature threshold of 11 °C for adult development was found. The development of juvenile parasitoids in B. tabaci lasted more than two months at the lowest temperature, but was only 14 days when temperature was 28 °C. The lower temperature threshold for immature development was 13.3 °C, yielding an average of 207 day‐degrees for the completion of development into adults. Juvenile mortality was high, varying from about 50% at 16 °C to about 30% at 22 °C and 28 °C. E. formosa preferred to oviposit in the 4th instar and prepupal stages of B. tabaci followed by the 2nd and 3rd instars. The preference for the pupal stage was low. The parasitoid used all instars of the whitefly for hostfeeding, with no apparent differences between the stages. The average duration of the oviposition posture was four minutes. Demographic parameters were calculated from life tables constructed from the data. The intrinsic rate of increase (rm) and the net reproductive rate (R0) increased with temperature from 0.0279 day−1 at 16 °C to 0.2388 day−1 at 28 °C and from about 12 at 16 °C to about 66 at 28 °C, respectively.
Differential antigen decay rates during digestion of molluscan prey by carabid predators
Authors: Symondson W. O. C. , Liddell J. E. 
Published: April 2011

AbstractCarabid beetles (Coleoptera: Carabidae) were fed upon slugs (Mollusca: Pulmonata) in the laboratory, and their crop contents analysed for mollusc remains, using an enzyme‐linked immunosorbent assay (ELISA) with an anti‐Arion ater (L.) haemolymph antiserum. Crop weight loss and antigenic recognition of prey proteins were examined as separate variables in a series of validatory experiments. Two model predators, Abax parallelepipedus Piller and Mitterpacher and Pterostichus madidus F., were fed upon two species of pest slugs, Deroceras reticulatum (Müller) and Arion hortensis Férussac. The fitting of regression equations to the transformed antigenic response data allowed the ‘half‐life’ and detection period to be calculated for each predator‐prey combination. Following a one hour feeding interval, the half‐life of the antigenic response to D. reticulatum remains was almost twice as long in P. madidus as that in A. parallelepipedus, and the detection period more than 2.5 times as long. However, covariant analysis showed that there was a significant difference between predator species in the rate at which detectability declined, but not in the rate of crop weight loss. When A. parallelepipedus was allowed to feed upon A. hortensis for eight hours, prey remains were still detectable at the end of the experiment, 13 days after feeding. Calibration of the differential rates of antigen decay and crop weight loss could potentially be used to calculate the size of the original meal, but only if prey species, and the time since feeding, can be determined. Potential solutions to these problems are discussed.
Déterminisme de la couleur des hôtes parasités par Trichogramma fuentesi
Authors: Rodríguez J. R. , Pintureau B. , Galán M. 
Published: April 2011

RésuméA Cuba, les oeufs hôtes parasités par Trichogramma fuentesi Torre (Hymenoptera: Trichogrammatidae) deviennent soit noirs, soit marrons. Une série de croisements entre Trichogrammes a permis de montrer que le déterminisme de ce caractère est sous la dépendance d'un locus portant deux allèles: Bh, dominant, confère une couleur noire à l'hôte; bh, récessif, confère une couleur marron. L'allèle bh étant plus fréquent dans la région orientale de Cuba, la plus chaude, nous avons suivi l'évolution des fréquences des deux allèles dans des populations expérimentales polymorphes placées à 23 °C et 30 °C. Dans toutes les conditions testées, bh a été désavantagé par rapport à Bh, sauf à 30 °C lorsque sa fréquence initiale était élevée (90%). La température n'explique donc certainement pas à elle seule le maintien du polymorphisme à Cuba.AbstractIn Cuba, during its larval development inside its host egg, Trichogramma fuentesi turns its host egg either black or brown. Crossings carried out between the two forms of T. fuentesi allowed to show that this character is determined by one locus with two alleles: Bh, dominant, colours the host black; and bh, recessive, colours the host brown. The bh allele is more frequent in the eastern region of Cuba which is also the warmest, than in the western region. We studied the evolution of frequencies of the two alleles in different experimental polymorphic populations at 23 °C and at 30 °C. In all tested conditions, bh was at a disadvantage by comparison with Bh, except at 30 ° C when its initial frequency was high (90%). Thus, temperature alone should certainly not explain the maintenance of the observed polymorphism in Cuba.
Effects of genetic and environmental host plant variation on the susceptibility of two noctuids to Bacillus thuringiensis
Authors: Meade Thomas , Hare J. Daniel 
Published: April 2011

AbstractTwo Apium graveolens var. rapaceum (L.) cultivars that differ in their suitability for the survival and growth of Spodoptera exigua (Hübner) and Trichoplusia ni (Hübner) were used to examine the effect of genetic and seasonal environmental variation in host plant suitability on the efficacy of Bacillus thuringiensis subsp. kurstaki (Berliner). The effects of host plant genotype and B. thuringiensis were generally independent, so that B. thuringiensis efficacy was greatest on the resistant host plant cultivar. Host plant suitability varied within growing season for both insect species but, while host plant suitability decreased with increasing plant age for T. ni, the response of S. exigua to plant age was not as clear. Within season variation in host plant suitability affected B. thuringiensis efficacy and the interaction between B. thuringiensis and host plant cultivar for S. exigua but not for T. ni. Soluble protein and Folin‐Denis phenolic concentrations of host plant tissue were not correlated with changes in host plant suitability to either insect species.
Reduction of insect pest attack on sorghum and cowpea by intercropping
Authors: Ampong‐Nyarko Kwesi , Reddy K. V. Seshu , Nyang'or Ruth A. , Saxena K. N. 
Published: April 2011

AbstractTwo experiments to establish the relationship between insect suppression by intercropping and grain yield in sorghum and cowpea were conducted under field conditions. Treatments consisted of monocrops and intercrops of sorghum and cowpea and an additional pair of monocultures and mixtures protected by insecticides. Intercropping reduced the numbers of stem borer, Chilo partellus in sorghum and thrips, Megalurothrips sjostedti in cowpea. In the monocropped, unprotected sorghum, yield was reduced by 28% compared to the protected monocrop, while reduction in the unprotected intercropped sorghum was 15% compared to the protected intercrop. Similarly, in the unprotected cowpea, monocrop yield was reduced by 94% and intercrop yield was reduced by 51%. Thus, there are yield advantages under conditions where intercropping reduces insect pest density. Intercropping can form a component of an integrated pest management programme.
The role of symbiotes in flight activity of Sitophilus weevils
Authors: Grenier A. M. , Nardon C. , Nardon P. 
Published: April 2011

AbstractThe flight activity (take‐off) of various strains of Sitophilus oryzae L. and S. zeamais Mots. (Coleoptera, Curculionidae) have been compared on wheat. It was shown that males are more active than females and that S. zeamais, is more active than S. oryzae. Furthermore, in the two species, when reared on wheat kernels, only symbiotic weevils were able to fly, while aposymbiotic insects did not. By supplementation of the diet with vitamins (pantothenic acid, riboflavin) and amino acids (phenylalanine and proline), this activity could be restored in part. The influence of symbiosis on the flight ability of Sitophilus weevil is discussed in relation to the energy metabolism (coenzymes, proline), the role played by symbiosis in this behaviour and its possible effect on the dissemination of the species.RésuméLes performances de vol de nombreuses souches de Sitophilus oryzae L. et S. zeamais Mots. (Coleoptera, Curculionidae) ont été comparées sur blé. Il s'avère que les mâles sont plus actifs que les femelles et que S. zeamais possède une meilleure aptitude au vol que S. oryzae. De plus, dans les deux espèces élevées sur blé, seuls les charançons normalement symbiotiques sont capables de voler, tandis que les aposymbiotiques ont perdu ce pouvoir. En complémentant la nourriture avec des vitamines (acide pantothénique et riboflavine) et certains acides aminés (phénylalanine et proline), cette activité a pu être restaurée en partie. L'influence de la symbiose sur l'aptitude au vol du charançon du genre Sitophilus est commentée en fonction du métabolisme énergetique (coenzymes, proline) et du rôle joué par la symbiose dans ce comportement qui permet d'augmenter la dissémination de l'espèce.
Efficiency of variable‐intensity and sequential sampling for insect control decisions in cole crops in the Netherlands
Authors: Shelton A. M. , Theunissen J. , Hoy C. W. 
Published: April 2011

AbstractA total of 24 commercial fields of cabbages and Brussels sprouts were sampled in a grid fashion with 20–25 equally spaced cells with four plants per cell. Using this data base of 80–100 plants, we conducted computer stimulations to compare the treatment decisions that would be made for the major insect pests using published sequential sampling programs and a newly developed variable‐intensity sampling program. Additionally, we compared the number of samples required to make the decision. At low thresholds (10–20%) for both Lepidoptera and cabbage aphids, variable intensity‐sampling required a smaller sample size and provided more reliable decisions, while at high thresholds (40–50%) sequential sampling provided more reliable decisions. In both procedures, the occurrence of incorrect decisions was minimal. The number of cases in which a decision would not be reached after a 40‐plant sample was lower for variable‐intensity sampling. Considering the number of samples required to make a correct decision and the greater need for reliable decisions at lower thresholds, variable‐intensity sampling was superior to sequential sampling. Additionally, variable‐intensity sampling has the advantage of requiring samples to be taken in a greater area of the field and thus increases the probability of detecting localized infestations. Although variable‐intensity sampling was not designed to classify pest populations for treatment decisions but rather to achieve sampling precision around the population mean, our present studies indicate that it can also be an effective method to aid in treatment decisions.
Location of ecdysteroid 22‐O‐acyltransferase in the larvae of Heliothis virescens
Authors: Kubo I. , Zhang M. , De Boer G. , Uchima K. 
Published: April 2011

AbstractLarvae of the tobacco budworm, Heliothis virescens, are resistant to high levels of ingested 20‐hydroxyecdysone which could cause potential inhibition to the development of many other lepidopteran species. This resistance is attributed to the ability of the larvae to metabolize this molting hormone to its 22‐acyl ester forms. When tobacco budworm larvae were fed large quantities of 20‐hydroxyecdyone, the hormonal metabolites were found in gut and fat body tissues. When incubated with 20‐hydroxyecdysone gut tissue converted 20‐hydroxyecdysone into its 22‐acyl ester metabolites. Lumen site of the midgut was found to be the major location of this bio‐transformation. In contrast, fat body tissue failed to convert 20‐hydroxyecdysone to 22‐acyl ester metabolites in vitro. After the oral injection of 3H‐ecdysone, the major metabolites formed were ecdysone 22‐acyl esters whereas the majority of 3H‐ecdysone was transformed to polar metabolites after it was injected into the hemocoel of the larvae. Similar distributions of ecdysteroid 22‐O‐acyltransferase and alkaline phosphatase activity in subcellular fractions demonstrates the co‐localization of these enzymes in plasma membrane of the gut epithelial cells. These results suggest that gut brush border membrane is the major site of ecdysteroid 22‐acyl ester formation in H. virescens larvae.
Increasing the availability of food and the reproduction of Poecilus cupreus in a cereal field by strip‐management
Authors: Zangger Adrian , Lys Jon‐Andri , Nentwig Wolfgang 
Published: April 2011

AbstractIn a 8 ha field the availability of food and the reproduction of the most abundant carabid beetle Poecilus cupreus L. (Carabidae, Coleoptera) was compared between a strip‐managed area (cereal area subdivided by strips of weeds and wild flowering herbs) and a conventionally treated cereal area. Data on phenology, biometry, quantity of the gut content and egg production were collected during the main reproduction period (April‐July). Females were found to be significantly larger and heavier in the strip‐managed area than in the control area. The higher weight (corrected for size) indicated better feeding conditions in the strip‐managed area, which was confirmed by having better filled crops. The state of egg development and the numbers of eggs in the ovaries indicated a prolongation of the reproduction period in the strip‐managed area, whereas females caught in the cereal area contained significantly fewer ripe eggs. The results of egg‐laying tests in the laboratory showed the same trend but did not confirm any significant differences because of a high rate of individual variation. All measurements from females point to a higher availability of food in the strip‐managed area and to an enhanced reproductive potential at this site. For males, on the other hand, the results did not reveal such a uniform trend.
Determining the frequency of heteropteran predation on sweetpotato whitefly and pink bollworm using multiple ELISAs
Authors: Hagler James R. , Naranjo Steve E. 
Published: April 2011

AbstractThe gut contents of field‐collected, predaceous Heteroptera were assayed for the presence of eggs of the sweetpotato whitefly, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and the pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) using multiple enzyme‐linked immunosorbent assays (ELISAs). Of seven species examined, Geocoris species and Orius tristicolor (Say) were the most frequent predators of sweetpotato whitefly with 32–39% of the individuals tested over the whole season scoring positive for whitefly antigens. With the exception of Lygus hesperus Knight, a major insect pest as well as a predator, the frequency of predation on pink bollworm eggs was much lower (0.7–14.3% positive over the season). Relatively few predators tested positive for both antigens (0.3–12.5%).
The relative acceptabilities of three Australian Menispermaceae as food plants for larvae of the fruitpiercing moth, Othreis fullonia
Authors: Fay H. A. C. 
Published: April 2011

AbstractThe acceptability of three widely distributed Australian Menispermaceae, Tinospora smilacina Benth., Sarcopetalum harveyanum F. Muell. and Stephania japonica (Thunb.) Miers, as food for larvae of the fruitpiercing moth, Othreis fullonia (Clerck), was examined in three laboratory experiments. When larvae were presented with plant species individually total development times were shortest on T. smilacina and longest on S. japonica, despite relatively similar consumption rates within most instars. T. smilacina elicited greater (P<0.05) relative growth rates than S. japonica in all instars except the 6th. In the second experiment, when larvae were allowed to select from each of the 3 plants, no S. japonica was chosen by 1st instars and it represented only 3.7% of food consumed by 2nd instars. Significantly more T. smilacina was eaten in each instar than S. japonica, and more than S. harveyanum except in the 2nd and 4th instars. The final experiment examined the abilities of larvae to switch hosts when forced after the 1st and 3rd instars. After the first or second food change largest average headcapsule widths were associated with feeding on T. smilacina as the most recent food. Feeding by final instars on T. smilacina also resulted in the shortest development time and highest puparial weights. While some larvae survived irrespective of plant sequence 83.3% of the recorded mortality occurred while larvae were exposed to S. japonica, principally during the 1st instar. These experiments lend support to field observations which suggest that T. smilacina is a major host of O. fullonia while S. japonica is not. S. harveyanum is probably an important alternate host when T. smilacina is scarce.