bluuebunny/crossref_metadata_2025_split huggingface dataset:
The biology and phenology of the citrus whitefly, Dialeurodes citri, on citrus in the Coastal Plain of Israel
Authors: Argov Yael , Rössler Yoram , Voet Hillary , Rosen David 
Published: October 2003

AbstractThe citrus whitefly, Dialeurodes citri (Ashmead) (Homoptera: Aleyrodidae) (CWF), is a polyphagous citrus pest, originating in S. E. Asia, which was first discovered in the Western Galilee region of Israel in 1975. The larval instars of CWF secrete honeydew, and the sooty mould fungus, which develops on the honeydew, causes damage to the tree and its fruit. In observations made in Israel between 1987 and 1991 CWF usually completed three generations per year, although a small proportion of the population had two or four generations. From October to April a combination of shortened photoperiod and reduced temperature arrest the development of CWF in the fourth larval instar. The average length of the life cycle from egg to adult emergence was 65 days in the first generation (April–June), 52 days in the second generation (July–August) and 8 months in the third generation (September–April). Under laboratory conditions of L16: D8 and 25 °C, the mean developmental time was 54 days, and the duration of the egg, first larval instar, second larval instar, third larval instar, fourth larval instar and putative pupa (red eyes) were 12.1, 6.5, 5.5, 7.6, 18, and 4.7 days, respectively. Adults prefer to lay their eggs on young, fully developed citrus leaves, but also oviposit on older leaves. The inner region and shaded sides of the tree are preferred for oviposition.
Jasmonic acid induces the production of gerbera volatiles that attract the biological control agent Phytoseiulus persimilis
Authors: Gols R. , Posthumus M.A. , Dicke M. 
Published: October 2003

AbstractJasmonic acid (JA) is a plant hormone that is involved in the induction of plant defence in response to herbivore attack. We studied the effect of exposure of gerbera leaves to JA on indirect plant defence, i.e. attraction of natural enemies of herbivores. Treatment of gerbera leaves with JA or feeding damage by the herbivorous spider mite Tetranychus urticae, both induced the production of a complex odour blend that attracts the predatory mite Phytoseiulus persimilis. This phytoseiid predator is a very effective biological control agent of the spider mite T. urticae. Comparison of headspace composition of gerbera leaves exposed to either JA or T. urticae revealed a large degree of resemblance, but some quantitative and qualitative differences were recorded. The major chemical group in both treatments is formed by the terpenoids which quantitatively comprised up to 80% of the total odour blend. These terpenoids included (E)‐4,8‐dimethyl‐1,3,7‐nonatriene, (E)‐β‐ocimene and linalool that are known to attract P. persimilis. Aldehydes, alcohols, esters and ketones, together with nitrogenous compounds formed the remaining constituents of the odour blend. The induction of predator attractants in plants by JA may be applied in biological control programs, which is discussed in this paper.
Differences in tomato spotted wilt virus vector competency between males and females of Frankliniella occidentalis
Authors: van de Wetering Fennet , van der Hoek Marieke , Goldbach Rob , Peters Dick 
Published: October 2003

AbstractPossible differences in tomato spotted wilt virus (TSWV) transmission vector competency between Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) males and females were investigated. The males of the Dutch reference population NL3 transmitted TSWV at a notably higher rate (57%) than the females (32%). The viruliferous males also transmitted more frequently within the first six days after adult emergence than the females. For both sexes, the transmission efficiency dropped with age, simultaneously with the consumption rate. The higher vector efficiency for males appeared to be a general phenomenon as this feature was also found for thirteen other F. occidentalis populations, which originated from distinct geographic regions.
The influence of oviposition phenology on survival in host races of Eurosta solidaginis
Authors: Horner John D. , Craig Timothy P. , Itami Joanne K. 
Published: October 2003

AbstractPhenological differences between host plants can contribute to allochronic isolation of host races of phytophagous insects. Host races of the gallmaking fly, Eurosta solidaginis, that live on different species of goldenrod (Solidago altissima and S. gigantea) exhibit different emergence phenologies. These differences could result from adaptation to corresponding phenological differences between the hosts in periods of optimal suitability for gall formation and survival to adulthood. In order to test this, some flies of each host race were allowed to emerge naturally while the emergence times of others were manipulated to correspond to the emergence and oviposition periods of the other host race. Percent gall formation and survival to adulthood were examined for three oviposition periods: the peak time of emergence and oviposition of the earlier‐emerging host race (that from S. gigantea), that of the later‐emerging host race (that from S. altissima), and a week after the peak emergence of the host race from S. altissima. Flies of both host races were allowed to ovipuncture plants of the appropriate species during each of these periods. Plant relative growth rates were measured during each of these periods. The experiment was repeated twice over a two‐year period. Relative growth rates of both host species were highest during the earliest oviposition period (the period during which the host race from S. gigantea normally emerges). Percent gall formation was significantly correlated with plant relative growth rate, but the coefficient of determination was low. In both years of the study, percent gall formation of both host races was highest during the earliest oviposition period (the period during which the host race from S. gigantea normally oviposits). Likewise, percent survival to adulthood in both host races was highest during the earliest oviposition period. There was no significant effect of oviposition period on the percent of larval death due to parasitism by Eurytoma gigantea or predation by Mordellistena unicolor. These results suggest that the host race from S. altissima does not emerge at the time that its host is optimally suited for gall formation or survival to adulthood. Therefore, differences in emergence phenologies do not appear to be due to corresponding phenological differences between the host species in suitability for gall formation or survival to adulthood.
Spring colonisation of orchards by Anthonomus pomorum from adjacent forest borders
Authors: Toepfer St. , Gu H. , Dorn S. 
Published: October 2003

AbstractThe early‐season dispersal of the overwintered apple blossom weevil, Anthonomus pomorum (L.) (Coleoptera: Curculionidae), is a crucial stage in the colonisation of dwarf apple orchards adjacent to forests. We have conducted release‐recapture studies with 1700 to 4000 marked weevils at two orchard sites in Switzerland over 2 years to characterise the spatial and temporal pattern of the dispersal process. The dispersal and colonisation of orchards in spring by overwintered weevils is dependent upon the prevailing temperature.An orientated dispersal from the forest border to the centre of the orchard was observed consistently, irrespective of the angle of the apple tree rows with respect to the forest border or of climatic conditions. The average dispersal distance of the weevils was 19 m. Approximately one third of the weevil population remained on the first tree encountered, the remainder of the population moved over short distances mainly along the tree rows. This dispersal pattern led to a strong ’edge effect‘ with higher numbers of weevils occurring at the edges adjoining the forests as compared to the centre of orchards. The relevance of these findings to population dynamics and management of the pest is discussed.
Niche overlap and interspecific association between Chilo partellus and Chilo orichalcociliellus on the Kenya coast
Authors: Ofomata V.C. , Overholt W.A. , Van Huis A. , Egwuatu R.I. , Ngi‐Song A.J. 
Published: October 2003

Abstract Chilo partellus (Swinhoe) and Chilo orichalcociliellus Strand (Lepidoptera: Crambidae) occur sympatrically on the Kenya coast and are injurious to maize and sorghum. Evidence over a period of 30 years indicates that the indigenous stem borer, C. orichalcociliellus, is being gradually displaced by the exotic stem borer, C. partellus. The two species have overlapping niches, but the specific mechanisms driving the displacement are unknown. The distribution and extent of niche overlap and interspecific association between C. partellus and C. orichalcociliellus were investigated in cultivated and wild host plants. No difference in the within‐plant distribution of the two borer species in maize and sorghum was found. A niche overlap of 83.7% between C. partellus and C. orichalcociliellus was found. A weak positive association was found between small‐, medium‐, and large‐sized larvae of C. partellus and C. orichalcociliellus. However, as larvae grew, the association decreased with no significant association at the pupal stage. No negative association was found between C. partellus and C. orichalcociliellus, suggesting that the two species do not avoid or directly harm each other. The partial displacement of C. orichalcociliellus may therefore, be attributed to intrinsically superior attributes of C. partellus that indirectly affect the survival of C. orichalcociliellus.
Effects of temperature and photoperiod on development and oviposition of the legume flower thrips, Megalurothrips sjostedti
Authors: Ekesi S. , Maniania N.K. , Onu I. 
Published: October 2003

Abstract Megalurothrips sjostedti is an economic pest of cowpea in tropical Africa. There are no reports of the effect of temperature on the development of the pest and no diapause has been detected. The developmental rate and reproduction of M. sjostedti was studied under six constant temperatures (14, 17, 20, 23, 26 and 29 °C ) and a photoperiod of L12:D12 in the laboratory. Total developmental time ranged from 33.1 days at 14 °C to 19.2 days at 26 °C. At 29 °C, all larvae died during hatching. Egg, larval and pupal stages required 94.3, 97.1 and 105.3 deg‐days (DD) above a threshold of 8.2, 9.1 and 10.4 °C, respectively, to complete development. Total developmental cycle was completed at 163.9 DD above a threshold of 12.6 °C. Adult longevity was lowest (11.1 days) at 29 °C and highest (28.7 days) at 14 °C. At constant temperatures, the highest pre‐oviposition period was observed at 29 °C under a photoperiod of L16:D8. Egg production also ceased at this temperature/photoperiod combination. Total fecundity was highest at 26 °C under L10:D14. At cyclical temperatures, pre‐oviposition period was longest (12.4 days) at 20/29 °C under L16:D8. Total fecundity was highest (168.4 eggs) at 14/26 °C under L10:D14, and lowest (8.2 eggs) at 20/29 °C under L16:D8. The significance of these findings in the management of M. sjostedti is discussed.
The influence of floral character on the foraging behaviour of the hoverfly, Episyrphus balteatus
Authors: Sutherland Jamie P. , Sullivan Matthew S. , Poppy Guy M. 
Published: October 2003

AbstractA bioassay to examine the foraging behaviour of the aphidophagous hoverfly, Episyrphus balteatus was used in which various stimuli purported to influence flower choice were tested using model flowers. In choice experiments, E. balteatus exhibited enhanced behavioural responses to the colour yellow, as previously seen in Eristalis by several workers. Previous suggestions that the generalist forager E. balteatus has no preference for colour are re‐examined in the light of this new evidence. The other advertisement cue tested, size, was also demonstrated to play an important role in determining foraging behaviour, with the smaller artificial flowers seemingly preferred. Of the rewards tested, E. balteatus showed preference for the greatest nectar concentrations, whilst increasing pollen did not affect behaviour. These bioassays provided an opportunity to isolate the individual components of decision‐making by E. balteatus during foraging. The separation of sexes and ages in these experiments permitted analysis of inter‐sexual and inter‐generation differences in behaviour, a factor apparently not investigated in previous work.
Effect of plant lectins on larval development of the legume pod borer, Maruca vitrata
Authors: Machuka J. , Van Damme E.J.M. , Peumans W.J. , Jackai L.E.N. 
Published: October 2003

AbstractThe legume pod‐borer Maruca vitrata (Fabricius), [Lepidoptera: Pyralidae] is a major constraint restricting increased cowpea production in tropical Africa and Asia. Since lectins are known to have insecticidal properties against several pests, a survey was undertaken to screen for the effects of 25 lectins from 15 plant families on the development of Maruca pod borer (MPB) larvae. The list included 8 galactose/N‐acetylgalactosamine‐, 7 mannose‐, 5 complex glycan‐, 2 sialic acid‐ and 3, N‐acetylglucosamine‐specific lectins. Feeding bioassays using artificial diet were carried out at 2% (w/w) topical levels. Although a total of 16 lectins had detrimental effects pertaining either to larval survival, weight, feeding inhibition, pupation, adult emergence and/or fecundity, only the Listera ovata agglutinin (LOA) (Orchidaceae) and Galanthus nivalis (Amaryllidaceae) agglutinin were effective against MPB larvae for all six parameters examined. Larval mortality and feeding inhibition caused by the most active lectin (LOA) was above 60%.
Dependence on host constituents controlling food acceptance by Manduca sexta larvae
Authors: del Campo C. Marta L. , Renwick J. Alan A. 
Published: October 2003

AbstractThe host range of Manduca sexta L. (Lepidoptera: Sphingidae) is restricted in nature to plants in the family Solanaceae. However, naive hatchling larvae often accept and continue their development on foliage from a wide spectrum of unrelated plants. In contrast, solanaceous‐experienced larvae refuse to feed on other plants. Experiments were designed to explore the role of constituents of various plants in this behavioral phenomenon. Fourth instar larvae reared on solanaceous hosts: tomato (Lycopersicon esculentum Mill.), potato (Solanum tuberosum L.), or tobacco (Nicotiana tabacum L.), and the leguminous non‐host cowpea (Vigna sinensis Savi), or on artificial diet based on wheat germ were tested for their acceptance or preference when offered a new diet in both choice and no‐choice situations. Under no‐choice conditions, acceptability of cowpea foliage was strongly affected by the larval dietary experience. Most larvae reared on solanaceous foliage did not feed, whereas those larvae reared on non‐solanaceous food readily accepted cowpea. Moreover, solanaceous foliage, leaf discs and extracts were readily accepted by larvae regardless of their dietary experience. Larvae reared on any of the solanaceous plants strongly preferred cowpea discs that were treated with solanaceous extract, while larvae reared on non‐solanaceous diets did not discriminate between treated and control discs. Assays of cowpea extracts as well as acceptance of cowpea discs treated with solanaceous extract indicated a lack of detectable deterrent in cowpea. Our results suggest that the mechanism for induced host specificity in M. sexta larvae involves development of a dependence on solanaceous chemical constituents. We argue that this dependence on host plant chemistry has adaptive significance.
Effects of enhanced UV‐B radiation on a weedy forb (Plantago lanceolata) and its interactions with a generalist and specialist herbivore
Authors: McCloud Eric S. , Berenbaum May 
Published: October 2003

AbstractAssessments of potential impacts of global climate change often focus exclusively on plants; however, as the base of most food webs, plants generally experience abiotic stresses concomitantly with biotic stresses. Longleaf plantain, Plantago lanceolata L., is a cosmopolitan temperate perennial weed that experiences a wide range of environmental conditions throughout its range. We examined the impacts of elevated levels of exposure to shortwave (UV‐B) radiation on this plant, on two herbivores associated with this plant, and on the plant‐herbivore interaction. Plantains were grown at 6 and 12 kJ m−2 d−1 BE300 UV‐B radiation and concentrations of iridoid glycosides (aucubin and catalpol), verbascosides, and nitrogen were measured. In terms of plant impacts, we found that iridoid glycoside concentrations were unchanged by elevated UV‐B radiation, whereas, in one experiment, the concentration of verbascosides in young leaves and levels of nitrogen in old leaves increased under elevated UV‐B radiation. Variation in plant chemistry due to leaf age and maternal family was greater than variation due to UV‐B exposure. When caterpillars were fed excised leaves from plants grown under elevated UV‐B, growth and survivorship of the specialist herbivore, Precis coenia Hbn. (Lepidoptera: Nymphalidae), were unaltered and growth of the generalist herbivore, Trichoplusia ni (Hbn.) (Lepidoptera: Noctuidae), was accelerated. When the caterpillars were reared on potted plants at high and low levels of UV‐B radiation, growth and survivorship of P. coenia were unchanged while growth of T. ni was significantly depressed by elevated UV‐B. Elevated UV‐B altered allocation patterns of above‐ground biomass in these plants; masses of crowns and reproductive tissue were reduced. UV‐B levels, however, did not affect distribution of damage to foliage inflicted by either species. In two additional experiments with artificial diet, designed to test the direct effect of UV‐B radiation on caterpillars, growth and survivorship of P. coenia were unaltered while survivorship of T. ni was significantly depressed when caterpillars were exposed to elevated UV‐B radiation. These studies collectively demonstrate that higher trophic level impacts of UV‐B‐induced changes in plants depend on the identity of the herbivore and its degree of adaptation not only to variation in hostplant quality but also variation in its light environment.
Wolbachia infection dynamics in experimental laboratory populations of Metaseiulus occidentalis
Authors: Johanowicz Denise L. , Hoy Marjorie A. 
Published: October 2003

Abstract Wolbachia infection in arthropods may cause incompatibility between uninfected females and infected males, but infected females can reproduce with both infected and uninfected males, theoretically increasing the proportion of infected individuals in a polymorphic population. To determine whether the proportion of Wolbachia‐infected Metaseiulus occidentalis (Nesbitt) (Acari: Phytoseiidae) in a polymorphic population would increase over time, three populations were initiated with 10% infected and 90% cured eggs and monitored for 12 generations. Wolbachia infection did not spread rapidly through the populations. Imperfect transmission rates and fitness costs were detected that could prevent the rapid spread of this Wolbachia. Thus this Wolbachia may not be useful as a drive mechanism for inserting useful genes into field populations of M. occidentalis.
Colour variation and polyethism of the soldier caste in the termite Macrotermes bellicosus
Authors: Konate Souleymane , Leuthold Reinhard , Hari Markus , Veivers Pamela 
Published: October 2003

AbstractBased on abdominal colour three categories of major soldiers were found in Macrotermes bellicosus (Smeathman) (Isoptera: Termitidae). The three main colour types, yellow, red and brown are due to the colour of the defence‐secretion stored in the labial gland's reservoirs. The order of these categories correlates with the uric acid titres of the whole individuals. It is concluded that colour could be used as a label for the relative age of a soldier. Age dependent polyethism was observed in soldiers: the individuals of the highest age class were the only ones leaving the nest to accompany the foraging workers, whereas all age categories were found inside the nest. After a significant loss of old individuals younger individuals show flexibility by replacing the missing outgoing nestmates. Caste regulation takes place by an increased rate of soldier development.
Metamorphosis‐associated proteolysis in Ceratitis capitata
Authors: Rabossi A. , Ación L. , Quesada‐Allué L.A. 
Published: October 2003

AbstractThe induction of several biochemical indicators of larval tissue histolysis in the Medfly, Ceratitis capitata (Diptera: Tephritidae) (Wiedemann) was studied. Using synchronized third instar larvae, we have determined the time of occurence of gut evacuation (12 h before puparium formation, bpf), disappearance of digestive enzymes (10 h bpf), and jumping from the food (8 h bpf). We can also correlate these events temporally with other early landmarks of metamorphosis.The decrease in protein content between 0 hours and 144 hours after puparium formation (0–144 h apf) corresponds to a sharp increase of total acid proteolytic activity measured in vitro from 0 to 44 h apf. This activity appears to be lysosomal, judging by the activation of other lysosomal markers, such as acid phosphatase and β‐glycosidases. The maximum proteolytic activity occurs during the pre‐pupa to pupa transition, i.e. during morphogenesis from the cryptocephalic to the phanerocephalic pupa. The results of endopeptidase inhibitor assays indicate that in dipterans, members of the aspartic and cystein proteinase families are responsible for the degradation of larval tissues.
Factors influencing the distribution and feeding of the larvae of Chironomus riparius
Authors: Osborne S. , Hurrell S. , Simkiss K. , Leidi A. 
Published: October 2003

AbstractChironomids are the most widely distributed group of insect larvae in freshwater environments. They are frequently the dominant primary consumers and show competitive interactions due to their requirements for foraging space in suitable substrates. In order to investigate the factors involved in substrate selection a simple choice chamber has been constructed that enables larvae of Chironomus riparius Meigen (Diptera, Chironomidae) to select wells, in which they can establish tubes, according to a number of chemical and physical parameters. The statistical probabilities of them aggregating randomly in this way were calculated for a variety of occupancies. The larvae developed distinct patterns of non‐random aggregation in the wells. Subsequent experiments showed that the presence of food at sites of burrowing affected settling but physical irregularities were necessary in order to facilitate burrowing and establish random patterns. Once the animals had selected their habitat the rate of feeding on the sediment was relatively constant with a gut‐clearance time of about 12 h although starving the animals before or after feeding affected the rate of passage of sediment through the anterior of the gut.