bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population growth and persistence when prey is diminishing in single‐species and two‐species systems of the predatory mites Euseius finlandicus, Typhlodromus pyri and Kampimodromus aberrans
Authors: Schausberger Peter 
Published: October 2003

AbstractPopulation growth and persistence of Euseius finlandicus (Oudemans), Typhlodromus pyri Scheuten and Kampimodromus aberrans (Oudemans) (Acari: Phytoseiidae) were studied in single‐species and two‐species systems on apple seedlings primarily infested by Panonychus ulmi Koch (Acari: Tetranychidae) in an environmentally controlled greenhouse. During the experiment, the seedlings developed natural infestations by Tetranychus urticae Koch (Acari: Tetranychidae), Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), and powdery mildew. Several weeks after the start of the experiment a condition of diminishing prey availability was created by use of hexythiazox treatments. Without heterospecific competitors, T. pyri attained a higher population level than E. finlandicus or K. aberrans when similar amounts of food (spider mites) were available to each. Population growth of T. pyri was decisively favoured by the presence of T. urticae. In the single‐species systems each predatory species persisted to the end of the experiment in spite of diminishing prey. In two‐species systems with T. pyri/E. finlandicus and T. pyri/K. aberrans that were started with the same number of individuals of each species, only T. pyri was left at the end of the experiment. Typhlodromus pyri became more numerous than the other species when prey was abundant (which was in accordance with the results of the single‐species groups) and finally displaced E. finlandicus and K. aberrans towards the end of the experiment. The following factors may have contributed to the dominance of T. pyri: (1) the ability of adult females to survive longer without food than those of E. finlandicus and K. aberrans, (2) the ability to complete juvenile development and to sustain reproduction with phytoseiid prey and (3) an advantage in foraging behaviour over K. aberrans and E. finlandicus at low spider mite levels. Euseius finlandicus predominated in the two‐species system E. finlandicus/K. aberrans, but both species persisted to the end of the experiment.
Species and habitat races in the chrysomelid Galerucella nymphaeae species complex in northern Europe
Authors: Nokkala Christina , Nokkala Seppo 
Published: October 2003

AbstractThe taxonomically controversial Galerucella nymphaeae species complex (Coleoptera, Chrysomelidae) contains at least two distinct species in northern Europe, G. nymphaeae (L.) consuming Nuphar luteum, and G. sagittariae (Gyll.), living mainly on Comarum palustre in southern Finland and on Rubus chamaemorus in northern Finland. By analyzing chromosomal polymorphisms in sympatric populations of G. nymphaeae and G. sagittariae, it was shown that the two species do not hybridize in nature. Chorion polypeptide analysis revealed fixed genetic differences between the two species. However, differences between species must be small, since hybridization is easily induced in the laboratory and F1 hybrids are fertile. Larvae of G. sagittariae cannot survive on Nuphar, and those of G. nymphaeae survive very poorly on Comarum and Rubus. Adults of G. sagittariae from Comarum or Rubus do not choose between these two food plants in laboratory conditions regarding dwelling, egg laying or feeding, but their avoidance of Nuphar is complete. Galerucella nymphaeae clearly prefers Nuphar, but may occasionally also sit, lay eggs or feed on terrestrial plants. It is suggested that G. nymphaeae and G. sagittariae represent sibling species and that the two forms of G. sagittariae, one feeding on Comarum and the other one on Rubus, are habitat races adapted to semiaquatic and terrestrial habitats, respectively. Adaptation to different habitats has created an effective premating barrier to gene flow, supporting the possibility that a sympatric mode of divergence has been involved in habitat race formation and speciation in the species complex.
The effects of physiological factors and host plant experience on the ovipositional activity of the sweet potato whitefly, Bemisia tabaci
Authors: Veenstra Klaas H. , Byrne David N. 
Published: October 2003

AbstractBoth egg load and levels of vitellogenin and vitellin increased when Bemisia tabaci Gennadius (Homoptera: Aleyrodidae), were deprived of host plants. These increases resulted in significant increases in rates of oviposition. There was no difference in total fecundity between whiteflies temporarily deprived of hosts and a control treatment that had continuous access to hosts. The results of previous exposure to a preferred host, melon (Cucumis melo), and a non‐preferred host, cotton (Gossypium hirsutum), were also examined. B. tabaci deposited significantly more eggs during a 6‐h period on melon than on cotton, regardless of host species they were previously confined to. In addition, whiteflies previously exposed to cotton, deposited more eggs than females previously exposed to melon. This higher rate of oviposition resulted in a low egg load as well as lower levels of vitellogenin and vitellin. Conversely, a low rate of oviposition led to high egg load and high levels of vitellogenin and vitellin. Individuals from the same treatment exhibited variation in egg load, which was negatively and significantly correlated with previous oviposition activity. We conclude that the effects of previous host plant exposure on oviposition were, in part, due to behavioral differences that are not related to the reproductive physiology.
The influence of size and duration of aphid infestation on host plant quality, and its effect on sugar beet yellowing virus epidemiology
Authors: Williams Iain S. , Dewar Alan M. , Dixon Anthony F.G. 
Published: October 2003

AbstractThis paper studies the influence of previous infestation on the host quality of sugar beet (Beta vulgaris L.) for aphids and the influence of previous infestation on sugar beet yellowing virus epidemiology. Sugar beet previously infested with Myzus persicae (Sulzer) or Aphis fabae Scopoli (Homoptera: Aphididae) had an improved host quality for subsequently infesting aphids of the same species. There was a significant negative relationship between the number of M. persicae infesting a plant and the proportion of those that died with a dark deposit in their stomachs, and a significant positive relationship between the number that settled on a plant and the number that infested it previously. Nymphs feeding on previously infested plants grew more rapidly than those on control plants. The beneficial effect of previous infestation persisted for at least 2 weeks and prolongation of the infestation beyond 2 weeks was of no further benefit to the aphids. Field grown sugar beet, previously colonised by M. persicae, was more susceptible to natural infestation by M. persicae up to 5 days after exposure. Previously infested plants were also more susceptible to infection with beet mild yellowing virus (BMYV) but not beet yellows virus (BYV), suggesting that the aphids on the previously infested sugar beet settled more readily and were more inclined to feed (and thus transmit BMYV) than aphids on the previously uninfested plants. The consequences for the control of sugar beet yellowing virus vectors are discussed.
Potential for intraguild predation and competition among predatory Coccinellidae and Chrysopidae
Authors: Phoofolo Mpho W. , Obrycki John J. 
Published: October 2003

AbstractIn a laboratory study two coccinellid species, Coleomegilla maculata (DeGeer) and Harmonia axyridis Pallas, completed preimaginal development on lacewing eggs, Chrysoperla carnea Stephens or pea aphids, Acyrthosiphon pisum (Harris) in similar times. Preimaginal survival on C. carnea eggs was similar to survival on A. pisum for all stages of C. maculata and H. axyridis. Coccinellid adults that developed on C. carnea eggs were smaller than adults reared on A. pisum. Coccinella septempunctata L. did not complete preimaginal development on C. carnea eggs. Chrysoperla carnea preimaginal developmental time was approximately 20 days when fed either C. maculata eggs or A. pisum. Chrysoperla carnea fed C. maculata eggs developed into smaller adults, compared to adults reared as larvae on A. pisum, Ostrinia nubilalis (Hübner) eggs, or A. pisum alternated daily with O. nubilalis eggs. C. carnea did not complete preimaginal development on H. axyridis eggs. Cannibalism occurred more frequently between C. carnea third instars than between C. maculata fourth instars. When a C. carnea third instar was paired with a C. maculata fourth instar, more C. maculata were preyed upon by C. carnea, regardless of the herbivorous prey density. In the field these two predator species may negatively affect each other and reduce their suppression of pest densities.
Host plant selection and development in Spodoptera exigua: do mother and offspring know best?
Authors: Berdegué Mariano , Reitz Stuart R. , Trumble John T. 
Published: October 2003

AbstractWe examined the ovipositional preference and larval development of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) on two common hosts in southern California, Chenopodium murale L. (Chenopodiaceae) and Apium graveolens L. (Umbelliferae) to determine if female oviposition preference is correlated with offspring performance. Greenhouse oviposition choice tests indicated that S. exigua oviposit more frequently on C. murale than on A. graveolens. However under laboratory conditions, larvae reared on C. murale had longer development times, lower relative growth rate, and lower survivorship than larvae reared on A. graveolens. larval and pupal masses were significantly greater on A. graveolens than on C. murale. Furthermore, pupal masses were significantly greater for individuals reared on A. graveolens than on C. murale. Because pupal masses and adult fecundity are positively correlated for Spodoptera spp., the fitness of S. exigua on A. graveolens is likely to be substantially higher than its fitness on C. murale. Despite better larval performance on A. graveolens, previous results from choice tests with whole plants and leaf discs indicate that the highly mobile S. exigua larvae strongly prefer C. murale over A. graveolens. Hypotheses attempting to explain this lack of correlation between larval and adult host preference versus development and survival in this system are discussed.
Biology and rearing of the fruit fly parasitoid Biosteres arisanus: clues to insectary propagation
Authors: Bautista Renato C. , Harris Ernest J. , Lawrence Pauline O. 
Published: October 2003

AbstractAspects of Biosteres arisanus (Sonan) (=Opius oophilus Fullaway) (Hymenoptera: Braconidae) development on the oriental fruit fly, Bactrocera (=Dacus) dorsalis (Hendel), were investigated to facilitate mass production in the insectary. Life table statistics were generated for cohorts of B. arisanus females. Overlap in the emergence of fruit flies and parasitoids necessitated a procedure for segregation, preferably before adult eclosion. Rate of parasitization by B. arisanus increased with host clutch size reaching a plateau at 20:1 host egg to female parasitoid ratio. Duration of the oviposition period influenced the level of host parasitization; host eggs were exposed to parasitoids for 24 h with minimal superparasitism. Females were highly productive within 3 weeks after emergence producing 40–70% females in the progeny. Adult males were shorter lived than females by ≈5 days. Based on a net reproductive rate (R0) of >16 daughters per female parent, a population increase of 10% was predicted each day. Handling procedures that could facilitate efficient production of parasitoids are discussed.
Influence of cereal leaf epicuticular wax on Diuraphis noxia probing behavior and nymphoposition
Authors: Ni Xinzhi , Quisenberry Sharron S. , Siegfried Blair D. , Lee Kit W. 
Published: October 2003

AbstractThe effect of cereal leaf surface wax on Diuraphis noxia (Mordvilko), the Russian wheat aphid, probing behavior and nymphoposition was evaluated. Ultrastructure of leaf epicuticular wax from wheat (Triticum aestivum L.) c.v. ‘Arapahoe’ and ‘Halt’ was different from barley (Hordeum vulgare L.) c.v. ‘Morex’, and oat (Avena sativa L.) c.v. ‘Border’. Both wheat cultivars had similar rod‐shaped epicuticular wax, while barley and oat plants had flakes. The chemical composition comparison of gas chromatograms also indicated that the extract of the two wheat cultivars had similar pattern of peaks, while the barley and oat leaves had similar peaks. Cereal variety significantly affected aphid probing behavior (P < 0.05), but wax removal using ethyl ether swab did not (P > 0.05). Aphids initiated significantly more probes on Border oat leaves than on Morex barley irrespective of wax removal, although total probing duration per aphid was not significantly different among the four cereals examined. Accumulative salivation duration per aphid on oat leaves with wax was significantly longer than other cereal leaves with wax, while accumulative ingestion duration per aphid on Arapahoe wheat and Morex barley was significantly longer than on oat. Nymphoposition of D. noxia on cereal leaves maintained on the benzimidazole‐agar medium showed that aphids produced a greater number of nymphs on Morex barley and less on Border oat leaves, although wax removal did not affect aphid nymphoposition. Removal of leaf epicuticular waxes from the 4 cereal genotypes using ethyl ether swab indicated that the influence of wax on plant resistance to D. noxia probing and reproduction was limited. Morex barley was the most favorable, while Border oat was the least favorable cereal host of D. noxia.
A gene controlling biosynthesis of isoorientin, a compound in corn silks antibiotic to the corn earworm
Authors: Widstrom N.W. , Snook M.E. 
Published: October 2003

AbstractThe corn earworm (Helicoverpa zea Boddie) is an important pest of corn (Zea mays L.), and its larvae sometimes cause severe ear damage to hybrids grown in the southeastern United States. The antibiotic compound isoorientin is present in silks of some corn inbreds at a concentration that is harmful to corn earworm larvae. The inbred T218, which produces biologically active levels of this compound (>2.0% dry weight), was evaluated in hybrid combination with two other non‐isoorientin producing inbreds to determine the mode of isoorientin inheritance in corn silks. Silk masses from individual ears of each parent, the F1, F2, first backcrosses, F3 families and selfed BC1 families were evaluated in 1994 and 1995 for isoorientin concentration. Reversed‐phase high performance liquid chromatography (HPLC) was used to make chemical determinations. Segregation ratios in the F2, first backcross to T218, F3 families and selfed BC1 families were tested. The tests were conclusive in the identification of a single recessive gene controlling high isoorientin concentration in the silks of inbred T218. Some evidence for modifiers exists, in that there was a statistically nonsignificant trend for more plants than expected to occur in the low isoorientin concentration classes. Development of inbreds with a high concentration of the simply inherited isoorientin in their silks will add to the arsenal of compounds available in corn silks to combat damage to corn by corn earworm larvae.
Sublethal effects of deltamethrin and propoxur on longevity and reproduction of German cockroaches, Blattella germanica
Authors: Lee C.Y. , Yap H.H. , Chong N.L. 
Published: October 2003

AbstractThe effects of sublethal doses of deltamethrin and propoxur, applied topically at LD10, LD30 and LD50 on German cockroaches, were studied by reciprocal crossing. Male and female longevities decreased curvilinearly with increasing sublethal doses of deltamethrin, and decreased linearly with increasing sublethal doses of propoxur. Fecundity of females treated with deltamethrin and propoxur was reduced with increasing sublethal doses of both insecticides. Oothecal production, oothecal hatchability and nymphal production also declined with increasing doses of deltamethrin and propoxur. Preoviposition and incubation periods were not affected by sublethal doses of deltamethrin and propoxur, although some significant differences were observed at certain oothecal numbers. Two‐way analysis of variance indicated that only treated females showed an effect on oothecal production while oothecal hatch and nymphal production were governed by both treated females and males. Insecticide susceptibility tests on the progeny of parents treated with sublethal doses demonstrated that these doses did not increase insecticidal tolerance in the F1 generation.
Reproductive barriers between the partially sympatric Colorado and false potato beetles
Authors: Boiteau Gilles 
Published: October 2003

AbstractThe partially sympatric Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), and the false potato beetle (FPB), Leptinotarsa juncta (Germar), were shown to possess a series of reproductive barriers that protect species integrity. A strongly stereotyped sequence of courtship behaviour insures that more than 85% of encounters between these congeneric species are terminated before copulation. The courtship behaviour of the FPB, described here for the first time, is similar to that for the CPB. However, the male FPB is more likely to walk off the female FPB and will repeat antennal tapping more frequently than the CPB before moving on to palp tapping and mating. Observations suggest that both species first use antennal tapping for an initial olfactory assessment of the object as a female insect of a given family or species and palp tapping for final sex recognition. If courtship behaviour fails to break up the hybridization pairs, there is no mechanical barrier to mating and sperm transfer takes place. However, there is gametic mortality. The FPB is more fecund than the CPB and seems less dependent than the CPB on multiple matings to reach its full reproductive potential.
Ecological significance of male attractant in the defence and mating strategies of the fruit fly, Bactrocera papayae
Authors: Hong Tan Keng , Nishida Ritsuo 
Published: October 2003

AbstractAfter being acclimatized to feeding on fruit flies, the Asian house gecko, Hemidactylus frenatus Duméril & Bibron (Gekkonidae:Squamata), consumed fewer methyl eugenol (ME) fed male fruit flies, Bactrocera papayae Drew & Hancock (Tephritidae: Diptera) than when offered ME‐deprived males. After one‐day exposure to only ME‐fed males, the geckos avoided feeding on female flies when in the presence of ME‐fed males. When mechanically disturbed, the ME‐fed males spontaneously ejaculated a rectal secretion which contains phenyl propanoids that deter the predator.The ME‐fed males also competed significantly better than normal (ME‐deprived) males for virgin females. Male B. papayae converts ME to three other phenyl propanoids which act in concert as a sex pheromone to attract females during courtship and as an allomone to the gecko.
Differences in water relations among the citrus leafminer and two different populations of its parasitoid inhabiting the same apparent microhabitat
Authors: Yoder Jay A. , Hoy Marjorie A. 
Published: October 2003

AbstractThe water balance relationships of adult females and pupae of two populations (Australian and Taiwan) of the parasitic wasp Ageniaspis citricola, a biological control agent of the citrus leafminer Phyllocnistis citrella, were compared to determine whether habitat preferences might differ between them. No differences were detected between Australian and Taiwan strains of the wasp during the pupal stage, but adult females from the Australian strain had lower net water loss rates than the parasitoid adults from Taiwan. This implies a greater moisture requirement by adults of the Taiwan strain, which should be considered before they are released into a new environment in classical biological control programs.
Effect of adult age, food, and time of day on sexual calling incidence of wild and mass‐reared Ceratitis capitata males
Authors: Papadopoulos Nikos T. , Katsoyannos Byron I. , Kouloussis Nikos A. , Economopoulos Aristidis P. , Carrey James R. 
Published: October 2003

AbstractThe sexual calling incidence of wild and mass‐reared Mediterranean fruit fly males, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), was studied at 25 °C and a photophase of 14 h starting at 0600 h. Wild males fed on yeast hydrolysate and sugar attained sexual maturity earlier and exhibited higher calling activity than males fed on sugar alone. In both sugar and yeast hydrolysate‐fed wild males, calling levels were high during the first hours of the photophase, declined at 0900–1000 h, then increased again reaching high levels between 1200 and 1500 h, and finally declined and ceased after 1600 h. Food deprivation for 8 h or more caused a significantly lower frequency of calling. Irradiated (sterile) and unirradiated mass‐reared males fed on either sugar and yeast or sugar alone did not differ in the age of attaining sexual maturity (maximum levels of calling occurred about 8 days earlier than in the wild males). However, irradiated males fed on sugar called less frequently than males in the other treatments of mass‐reared males. The daily rhythm of calling in protein and sugar‐fed irradiated males differed somewhat from that of wild males. Calling was recorded at high levels from the beginning of the photophase until 1300 h without any decrease at 0900–1000 h. It then decreased to very low levels from 1500–1800 h and increased slightly at 1900 h. These findings are discussed in relation to the mating behavior of the fly and to the effectiveness of released sterile males in Sterile Insect Technique programs.
Host selection behaviour of deathwatch beetle, Xestobium rufovillosum: Oviposition preference choice assays testing old vs new oak timber, Quercus sp.
Authors: Belmain S.R. , Blaney W.M. , Simmonds M.S.J. 
Published: October 2003

AbstractIn a choice bio‐assay adult female deathwatch beetles were offered two dendrochronologically dated wood blocks from oak timber to study oviposition preference behaviour. There was a clear preference for ovipositing on old wood dating from the 13th to 19th centuries rather than new wood from the 20th century. Control, same‐century choice, experiments showed that beetles will oviposit on young wood and that the age of the wood does not alter the overall oviposition potential. Oviposition frequency varied with insect age. Fecundity of insects collected from an infested building was similar to that of insects maintained in culture.
Differential cytotoxic effects of azadirachtin on Spodoptera frugiperda and mouse cultured cells
Authors: Reed Elizabeth , Majumdar Shyamal K. 
Published: October 2003

AbstractAzadirachtin is a natural biopesticide extracted from the neem tree (Azadirachta indica); however, its safety to mammals is not well documented. This study examined the influence of azadirachtin on the proliferation and morphology of Spodoptera frugiperda insect cells (SF‐9), and mouse erythroleukemia cells (MEL‐GM 86). Cell kinetic studies conducted at 24 h intervals for 144 h showed that azadirachtin treatments (0.05, 0.20 and 0.50 μg/ml) inhibited cell multiplication of the SF‐9 cells. This inhibitory effect was dose dependent. Conversely, azadirachtin at 30 μg/ml did not reduce MEL‐GM 86 cell proliferation. SF‐ 9 cells displayed an increase in cell swelling and cell abnormalities after 48 h of treatment with azadirachtin, whereas no such changes were detected in MEL‐GM 86 cells. A scanning electron microscope study revealed that treatment with an azadirachtin concentration as low as 0.10 μg/ml induced cell swelling and caused distortions on the cell surface ultrastructure of SF‐9 cells characterized by blebbing and holes after 48 h of treatment. However, these effects were not seen in the azadirachtin‐treated MEL‐ GM 86 cells.