bluuebunny/crossref_metadata_2025 huggingface dataset:
Host‐feeding and egg maturation by Pachycrepoideus vindemiae
Authors: Phillips D. S.
Published: April 2011

Pachycrepoideus 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

We 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

In 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

Adult 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

Carabid 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

A 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.

In 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

Two 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

Two 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

The 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.

Les 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

A 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

Larvae 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

In 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

The 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

The 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.
Trade‐offs in responses to host plants within a population of a generalist herbivore, Choristoneura rosaceana
Authors: Carrière Yves , Roitberg B. D.
Published: April 2011

Evolutionary constraints on the ability of herbivores to efficiently use a set of phytochemically similar hosts, while maintaining a high performance on phytochemically different hosts, are central in explaining the predominance of host specialization in phytophagous insects. Such feeding trade‐offs could be manifested within insect populations as negative genetic correlations in fitness on different host species. We tested the hypothesis that feeding trade‐offs were present within a population of the obliquebanded leafroller, Choristoneura rosaceana (Harris). Components of fitness were measured in families originating from an apple orchard that were fed on four host‐plant species in the laboratory. Under the conditions of this experiment, all across‐host genetic correlations were strongly positive, suggesting that this population comprised true generalists. With the exception of diapausing propensity, the heritability of the fitness components tended to be lower in caterpillars fed on apple leaves than in insects fed other hosts. This suggests a constraint on the selective response of the fitness components in the orchard environment.
Population dynamics of the potato tuber moth on processing tomatoes in Israel
Authors: Gilboa Smadar , Podoler Haggai
Published: April 2011

The potato tuber moth (PTM), Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is a major pest of processing tomatoes, Lycopersicon esculentum Mill. (Solanaceae), in Israel. The larvae penetrate the tomato fruit through the stem end and present a serious threat to crop quality. Foliage and fruit samples were taken in nine commercial tomato fields located in Israel's three main tomato growing areas, two of which are potato growing areas as well. PTM was not found where potatoes were absent. Potato harvest in nearby fields was found to be the most significant factor affecting seasonal trends in PTM population density in tomatoes. All four larval instars were found in foliage on all sampling dates. Significantly higher proportions of first instars were found during the population density increase which followed potato harvest. Damaged fruits did not contain first instar larvae, indicating that PTM never undergoes complete development within tomato fruit. Fruit damage levels at harvest were positively correlated to the peak mean population densities on foliage and the date they were observed. In tomato fields not adjacent to potatoes, infestation was first observed at the edge of the field. Both before and after the potato harvest in nearby fields, population density at the edge of the field was significantly higher than at the center. In tomato fields adjacent to potatoes, no significant differences were found between population densities at the edge and center before the potatoes were harvested. After the potato harvest, population density at the center of tomato fields was higher than at the edge.
Potentialités prédatrices de Forficula auricularia sur le psylle du poirier Cacopsylla pyri
Authors: Lenfant C. , Lyoussoufi A. , Chen X. , d'Arcier F. Faivre , Sauphanor B.
Published: April 2011

Reconnu comme agent régulateur des populations aphidiennes de diverses cultures, Forficula auricularia L. est également décrit comme potentiellement actif sur les Homoptéres Psyllidae. Nous avons évalué en conditions de laboratoire puis semi‐contrôlées en verger les composantes numériques et spatiales de la prédation de F. auricularia sur le psylle du poirier, Cacopsylla pyri (L.). Pour de faibles densités de proies, le poids consommé par une larve du 3ème stade est équivalent sur oeufs de psylles et sur une proie alternative constituée d'oeufs d'Ephestia kuehniella Zeller. Le maximum journalier s'établit à 10 mg pour ce stade larvaire, soit plus d'un millier d'oeufs de psylles. Les tests révèlent une réponse de type densité ‐ dépendant, aboutissant à une forte réduction de la taille des agrégats de la proie. La prédation des larves de 3ème et 4ème stade de F. auricularia s'exerce sur tous les stades préimaginaux de C. pyri. La colonisation au printemps de la strate arborée par les larves du 3 ème stade quittant le terrier maternel coîncide avec les pontes de 2ème génération de psylles, phase de multiplication la plus intense de ce ravageur. Les effectifs en vergers de ce prédateur polyphage et univoltin sont souvent élevés et peu dépendants de ceux de la proie. Compte tenu de sa capacité prédatrice sur le psylle, il paraît justifié de raisonner les interventions chimiques de manière à préserver ses populations en vergers de poiriers.

Potential of Forficula auricularia L. as predator of pear psylla Cacopsylla pyri (L.).

Forficula auricularia L. is a well known aphid predator, and is also described as potentially active on Psyllidae. We studied the numeric and spatial components of the predation of F. auricularia on pear psylla, Cacopsylla pyri (L.) under laboratory and semifield conditions. At low prey density, a young third‐instar larvae consumed as many psylla eggs as Ephestia kueheniella Zeller eggs, offered as alternative prey. The functional response to prey density revealed a maximum daily consumption of 10 mg per larvae, i.e. more than 1000 psylla eggs. The tests revealed a density‐dependent response, which strongly reduced the size of large prey groups. Third and fourth instar earwigs consumed all preimaginal psylla instars. In the spring, colonisation of pear trees by the third instar earwigs coincides with the egg‐laying of the 2nd generation of C. pyri. The natural populations in orchards of this univoltine and polyphagous predator are little dependent of the prey population. Because of F. auricularia high predatory capacity, its destruction by chemicals should be avoided in pear tree orchards.
The influence of glucosinolates and sugars on feeding by the cabbage stem flea beetle, Psylliodes chrysocephala
Authors: Bartlet E. , Parsons D. , Williams I. H. , Clark S. J.
Published: April 2011

Agar was used as an artificial substrate to investigate the feeding behaviour of the cabbage stem flea beetle, Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae), an important pest of winter oilseed rape (Brassica napus) in Europe. Both glucosinolates and sugars stimulated feeding when added to agar. The amount of feeding that occurred was affected by the type and concentration of glucosinolate and sugar and also by combinations of components. Although glucosinolates were potent feeding stimulants for P. chrysocephala, they were not a prerequisite for feeding, nor does it seem likely that glucosinolate profiles are used by this species to discriminate amongst cruciferous plants at the gustatory level.
Selection response of the Colorado potato beetle for adaptation to the resistant potato, Solanum berthaultii
Authors: França Félix H. , Plaisted Robert L. , Roush Richard T. , Via Sara , Tingey Ward M.
Published: April 2011

Thirty cohorts of the Colorado potato beetle (CPB) were reared for ten consecutive generations on the cultivated potato, Solanum tuberosum, and on two accessions (PI 473331 and PI 473334) of the resistant wild species, S. berthaultii. At each generation, selection was imposed for increased survival, decreased development time, and for increased fecundity. Although several parameters responded to selection, net replacement rate (R0) on S. berthaultii was consistently less than 1/3 that on cultivated potato. At the tenth generation, each S. tuberosum strain female replaced herself with 110 daughters, whereas females from strains reared on PI 473334 and PI 473331 produced an average of 30 and 7 daughters, respectively. Slopes of the R0 regression lines for populations reared on S. tuberosum and S. berthaultii did not differ from zero, indicating no significant response to selection. Our findings suggest that populations of the Colorado potato beetle may have genetic variability in some performance traits for adaptation to S. berthaultii, but that adaptation is unlikely to occur as rapidly as previously reported.
Temperature‐allelochemical interactive effects on performance of Manduca sexta caterpillars
Authors: Stamp N. E. , Temple M. P. , Traugott M. S. , Wilkens R. T.
Published: April 2011

A series of experiments was conducted to ascertain the effects of temperature and allelochemicals on the performance of an insect herbivore, with the goal of methodically expanding the cumulative data set on interactive effects of temperature and allelochemicals. The allelochemicals examined were caffeine, chlorogenic acid, quercetin, tannic acid and tomatine with the thermal regimes 20:15 °C versus 30:15 °C. Growth, molting time and food utilization efficiencies of third instar tobacco hornworms (Manduca sexta (L.)) were measured. Our results indicated that reductions in developmental rate by the phenolics were primarily due to effects occurring around and during molt initiation, that different phenolics may affect molt processes differently, and that some of the effects of the phenolics were a function of temperature, with greater negative effects at cool temperature. Negative effects of caffeine were most pronounced earlier in the stadium rather than during molt processes and, for some variables, the effect of caffeine was also a function of temperature.
Dispersal of adult female fig wasps: 2. Movements between trees
Authors: Ware Anthony B. , Compton Stephen G.
Published: April 2011

Fig wasps (Chalcidoidea, Agaonidae, Agaoninae) are the exclusive pollinators of fig trees (Ficus spp., Moraceae). Fig development on the African fig tree, F. burtt‐davyi, is normally synchronised on individual trees, but not between trees. Consequently the females of each generation of the pollinating species (Elisabethiella baijnathi) have to disperse to other trees to find ‘receptive’ figs which are suitable for oviposition. This paper examines this aspect of fig ‐ fig wasp biology. The flight speed of insects is closely linked to their size, and directional flight is difficult for small insects, such as fig wasps, in all but the lightest of winds. We investigated the movements of fig wasps between trees using sticky traps placed around fig trees or near cotton bags containing figs. Away from the trees, the densities of flying wasps at different heights was also determined. When the wasps disperse from their natal figs they take off near‐vertically. They are unable to exert directional control once they enter the air column and are subsequently blown downwind. Near receptive host trees the wasps appear to lose height and then fly upwind at speeds of around 25 cm/sec.
Effect of photoperiod and thermoperiod on the eclosion rhythm of Trichogramma evanescens
Authors: Zaslavski V. A. , Zinovjeva K. B. , Reznik S. Ya. , Umarova T. Ya.
Published: April 2011

The dynamics of adult eclosion in Trichogramma evanescens Westw. were studied under (1) constant light and temperature of 20 °C, (2) photoperiods L12:D12 and L16:D8 at 20 °C, (3) thermoperiod 4 h 27 °/20 h 20 °C at constant light, (4) joint action of photo‐ and thermoperiod. The emergence was arhythmic in constant light combined with constant temperature, while a sharp monophasic rhythm was observed with the isolated action of photo‐ or thermoperiod. The ‘light‐on’ and ‘temperature step‐up’ signals were shown to act in one direction. When both signals were combined, they manifested themselves as competing entraining stimuli which, in turn, revealed an apparent individual variation in relative reactivity to the light and temperature signals. Some perspectives which follow from these observations are discussed.
Small plot mating disruption trials for tufted apple bud moth, Platynota idaeusalis, in Pennsylvania apple orchards
Authors: Felland C. M. , Hull L. A. , Barrett B. A. , Knight A. L. , Jenkins J. W. , Kirsch P. A. , Thomson D. R.
Published: April 2011

Mating disruption treatments for the tufted apple bud moth (TABM), Platynota idaeusalis (Walker), were tested in small plot trials in apple orchards in Pennsylvania. Treatments were evaluated by fruit injury and by capture of male TABM in traps baited with synthetic pheromone sources or virgin females. The TABM pheromone is a two component isomeric blend of E‐11‐tetradecen‐1‐ol (E11–14:OH) and E‐11‐tetradecenyl acetate (E11–14:Ac). A 50:50 ratio of these two components was used in standard monitoring septa and in mating disruption treatments released from either hollow fibers (‘fiber’) or PVC tubes (‘PVC’). Other pheromone blends tested included a 90:10 ratio of E11–14:Ac and E11–14:OH (‘EAc’) and its reverse (‘EOH’), mixture ‘EAc’ with 30% of the Z‐isomers (‘low EAc’), and a blend similar to the preceding with 2% Z9–12:Ac (‘generic’). These other blends were released from multi tube tape (‘tape’) or Shin‐Etsu type rope (‘rope’) dispensers. Seasonal dispenser release rate in mg ha−1 h−1 was ca. 30 for the ‘rope’ dispensers, 14 for ‘PVC’ and 6 for ‘fiber’. ‘EAc‐tape’ and ‘EOH‐tape’ were equally effective in reducing catches of males in traps baited with synthetic lures and in traps baited with virgin females. Both treatments also reduced fruit injury. ‘EAc‐rope’, ‘fiber’ and ‘PVC’ also were generally effective; whereas, the ‘low EAc’ and ‘generic’ treatments reduced trap capture less than 90% and did not reduce fruit injury. Dispenser density was positively correlated with reduction in trap capture for the ‘low EAc‐rope’ and ‘genericrope’ treatments. Traps loaded with ‘fiber’ dispensers captured more male TABM than the other treatments in non‐pheromone permeated environments. Trap capture of other tortricids was reduced in pheromone treatments. ‘EAc‐rope’ and the ‘TABM’ treatments provided mean (s.e.) percent reduction in trap catch of 99.5 (0.4) and 42.9 (10.1), respectively, for the redbanded leafroller, Argyrotaenia velutinana (Walker), and 90.4 (6.8) and 90.4 (1.3), respectively, for the obliquebanded leafroller, Choristoneura rosaceana (Harris).
Side‐effects of insecticides on two erigonid spider species
Authors: Dinter A. , Poehling H.‐M.
Published: April 2011

The current rearing technique for Erigone atra (Blackwall) and Oedothorax apicatus (Blackwall) (Araneae, Erigonidae) was improved. To reduce time spent rearing on live fruit flies the spiders were kept on a culture of the Collembola species Lepidocyrtus lanuginosus (Gmelin) (Entomobryidae). Side‐effects on spiders of two pyrethroid insecticides (fenvalerate and lambda‐cyhalothrin) and one carbamate insecticide (pirimicarb) were tested. Sensitivity of adults of both sexes and juveniles to insecticides and their influence on the rate of emergence of spiderlings from cocoons were investigated using topical application, spraying or residual contact. LD50 values for adults ranged from 0.49 to 2.52 ng a.i./spider for lambda‐cyhalothrin and from 5.75 to 98.20 ng a.i./spider for fenvalerate. Topical application also resulted in up to a week's delay of web‐building. A moving laboratory spraying equipment was used to spray spiders with different insecticide dosages and water volumes. Pyrethroids sprayed onto adults in webs had stronger effects than pyrethroids sprayed onto sitting or walking spiders on the soil surface. Residual contamination caused higher mortality of spiders after contact with lambda‐cyhalothrin than fenvalerate. In all tests, males were more susceptible to pyrethroids than females; this difference was related to body weight. Mortality rate was higher for E. atra than for O. apicatus. Both pyrethroids were also toxic to spiderlings. Lambda‐cyhalothrin inhibited emergence of E. atra spiderlings from cocoons. Pirimicarb was harmless to both spider species.
Cholesterol oxidase: an oöstatic and larvicidal agent active against the cotton boll weevil, Anthonomus grandis
Authors: Greenplate J. T. , Duck N. B. , Pershing J. C. , Purcell J. P.
Published: April 2011

The enzyme cholesterol oxidase (E.C. 1.1.3.6), purified from Streptomyces culture filtrate was previously found to have oral insecticidal activity on neonate larvae of the boll weevil (Anthonomus grandis grandis Boheman) from a laboratory population. In the present study, second instar larvae were also controlled by the enzyme at diet concentrations similar to those which control neonates (12 day LC50 = 2.4 μg.ml−1 in diet). Larvae from field‐collected adults were similarly susceptible to cholesterol oxidase in the diet. When ingested by adult females during the mating/pre‐oviposition period, cholesterol oxidase greatly reduced subsequent oviposition (83% reduction in eggs laid as compared to controls) and larval survival (97% reduction from controls). Dissection of treated adult females revealed poorly developed ovaries and few developing oöcytes. These studies were conducted to further evaluate the utility of cholesterol oxidase in a program to establish boll weevil‐resistant transgenic cotton.
The transfer of pyrethroid resistance resulting from crosses between resistant German cockroaches and susceptible Asian cockroaches
Authors: Ross Mary H. , Cochran Donald G.
Published: April 2011

Crosses were made between the Asian cockroach, Blattella asahinai Mizukubo, and resistant strains of the German cockroach, B. germanica (L.), to assess the transfer of pyrethroid resistance to the progeny and to study the inheritance mechanism(s) involved. It was shown that the strain of Asian cockroaches studied was susceptible to four pyrethroids. F1 progeny were essentially susceptible to the same compounds. Tests with F2 progeny and those from backcrosses to the resistant parent indicated that the data for each pyrethroid fit an hypothesis of simple, autosomal, nearly completely recessive inheritance. The results are discussed from the standpoint of the impact of the Asian genome on the inheritance mechanism(s).
Assessment of Trichogramma species for biological control of forest lepidopteran defoliators
Authors: Bai B. , Çobanoĝlu S. , Smith S. M.
Published: April 2011

In a laboratory study, we determined the potential of three Trichogramma (Hymenoptera: Trichogrammatidae) species, T. brassicae Bezdenko, T. minutum Riley and T. nr. sibiricum Sorokina, for biological control against six species of forest lepidopteran pests, black army cutworm, hemlock looper, eastern spruce budworm, western spruce budworm, white‐marked tussock moth, and gypsy moth. Females of each parasitoid species were offered eggs from each of the six host species. Parasitization and the effect of the host species on the emerging progeny were examined and recorded. Trichogramma minutum had the broadest host range and successfully parasitized four host species out of the six offered. Trichogramma nr. sibiricum had the narrowest host range and parasitized only two species of hosts. Of the six host species, black army cutworm was the most preferred by all three Trichogramma species; white‐marked tussock moth and gypsy moth were not parasitized by any parasitoids. There was a positive correlation between the size of female offspring and their corresponding egg complement in all three parasitoid species. The developmental time of parasitoids from egg to adult was influenced by both the parasitoid and host species. Our results suggest that T. minutum has the greatest potential for biological control against various forest lepidopteran pests and that the black army cutworm may be the best target candidate for further study.
Effects of bean and wheat α‐amylase inhibitors on α‐amylase activity and growth of stored product insect pests*
Authors: Pueyo José J. , Morgan Thomas D. , Ameenuddin Nusheen , Liang Chao , Reeck Gerald R. , Chrispeels Maarten J. , Kramer Karl J.
Published: April 2011

Insect α‐amylase inhibiting and/or growth inhibiting activities of proteinaceous inhibitors from red kidney bean (Phaseolus vulgaris) and hard red winter wheat (Triticum aestivum) were examined. The bean inhibitor was most effective in vitro against α‐amylases from the red flour beetle (Tribolium castaneum) and the confused flour beetle (T. confusum), followed by those from the rice weevil (Sitophilus oryzae) and yellow mealworm (Tenebrio molitor). The insect enzymes were from two‐ to 50‐fold more susceptible than human salivary α‐amylase. When the inhibitors were added at a 1% level to a wheat flour plus germ diet, the growth of red flour beetle larvae was slowed relative to that of the control group of larvae, with the bean inhibitor being more effective than the wheat inhibitor. Development of both the red flour beetle and flat grain beetle (Cryptolestes pusillus) was delayed by 1% bean inhibitor, but development of the sawtoothed grain beetle (Oryzaephilus surinamensis) and lesser grain borer (Rhyzopertha dominica) was not affected by either the bean or wheat inhibitor at the 1% level. Rice weevil adults fed a diet containing 1% bean or wheat inhibitor exhibited more mortality than weevils fed the control diet. When the wheat amylase inhibitor was combined with a cysteine protease inhibitor, E‐64, and fed to red flour beetle larvae, a reduction in the growth rate and an increase in the time required for adult eclosion occurred relative to larvae fed either of the inhibitors separately. The bean inhibitor was just as effective alone as when it was combined with the protease inhibitor. These results demonstrate that plant inhibitors of insect digestive enzymes act as growth inhibitors of insects and possibly as plant defense proteins, and open the way to the use of the genes of these inhibitors for genetically improving the resistance of cereals to storage pests.
Oviposition preferences and larval performance of a flower‐feeding weevil, Coelocephalapion aculeatum, in relation to host development
Authors: Heard Timothy A.
Published: April 2011

The oviposition behaviour of Coelocephalapion aculeatum Fall (Coleoptera: Apionidae), a host specific florivore exploiting an ephemeral resource, was studied in relation to host development. Immature inflorescences of its host, the weed Mimosa pigra L. (Mimosaceae), were categorised into 5 developmental stages ranging from first appearance to one day before opening. The duration, weight, percent abortion, and nitrogen content of each stage were measured. Oviposition preferences of C. aculeatum for all inflorescence stages were determined in multiple choice trials. Newly hatched larvae were transferred into inflorescences of each stage to determine larval survival as a function of stage. Numbers of eggs laid into inflorescences generally correlated with larval survival except that oviposition was greater in stage 4 inflorescences than expected from the larval survival. Numbers of eggs laid into inflorescences generally correlated with their carrying capacity except that adults avoided stage 5 inflorescences in which larval survival was low. The evolution of oviposition preferences of C. aculeatum appears to have been influenced by two opposing selective forces. The need to complete development before the inflorescence deteriorated would have selected for oviposition in young inflorescences. The greater availability of food and lower probability of abortion offered by older inflorescences would have selected for oviposition in these. The net outcome of these pressures has resulted in the observed oviposition strategy.
Abdominal gland secretion of Bledius rove beetles as an effective defence against predators
Authors: Steidle Johannes L. M. , Dettner Konrad
Published: April 2011

The biological function of the abdominal gland of the rove beetle genus Bledius (Coleoptera: Staphylinidae: Oxytelinae) was examined using behavioural criteria. The attractant effect of the abdominal secretion on the Bledius predators Dyschirius obscurus and D. thoracicus (Carabidae), described in the literature, was identified as artificial. In choice experiments the secretion showed repellent effects on natural predators of Bledius furcatus, B. spectabilis and B. arenarius. In predator‐prey encounters with Cataglyphis bicolor (Formicidae) and Labidura riparia (Dermaptera) the gland secretion of B. furcatus induced cleaning behaviour. When attacked by C. bicolor the chance of survival for B. furcatus was increased by the presence of the abdominal gland secretion. This clearly shows that the abdominal gland of the genus Bledius is used for defensive purposes.
Cleome monophylla essential oil and its constituents as tick (Rhipicephalus appendiculatus) and maize weevil (Sitophilus zeamais) repellents
Authors: Ndungu Mary , Lwande Wilber , Hassanali Ahmed , Moreka Lambert , Chhabra Sumesh Chander
Published: April 2011

The repellency of the essential oil of the shrub Cleome monophylla (Family: Capparidaceae) and identified constituents of the oil were evaluated against the livestock tick, Rhipicephalus appendiculatus and the maize weevil, Sitophillus zeamais. In a tick climbing repellency bioassay, the oil of C. monophylla exhibited repellency which, at the highest dose, was comparable to that of the commercial arthropod repellent N, N‐diethyl toluamide (DEET). In a Y‐tube olfactometer bioassay, C. monophylla oil showed higher or comparable repellency against S. zeamais relative to DEET at all the doses tested. 14 Compounds were identified in the C. monophylla oil by GC, GC‐MS and coinjection with authentic samples. Terpenolene was found to occur in largest quantity (14%) followed by 1‐α‐terpeneol (10%), pentacosane (9%), (α + β)‐humulene (8%), phytol (5%) and 2‐dodecanone (4%). The most repellent components against R. appendiculatus and S. zeamais were 1‐α‐terpeneol and 2‐dodecanone. The overall pattern of repellency activity of the C. monophylla constituents with respect to the two arthropods was, however, different. The potential of C. monophylla in tick and maize weevil control is discussed.