bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant quality or quantity? Host exploitation strategies in three Chrysomelidae species associated with Asteraceae host plants
Authors: Obermaier Elisabeth , Zwölfer Helmut 
Published: October 2003

AbstractPhytophagous insects which feed on the leaves of herbaceous host plants have to adapt their life histories to the fact that protein nitrogen is usually highest in growing tissues in spring. We monitored field populations of larvae and adults of three chrysomelid species (Galeruca tanaceti (L.) (main host Achillea millefolium (L.) Yarrow), Cassida rubiginosa (Mueller) (main host Cirsium arvense (L.) Scop.) and Oreina luctuosa (Suffrian) (host Centaurea scabiosa (L.)) together with the amount of protein nitrogen of their food resources and host plant biomass. As expected, the development of host quality, measured as concentration of protein nitrogen, and host plant biomass showed inverse trends during the season. The euryphagous G. tanaceti attacks Achillea early and profits from high nitrogen concentrations in the leaves. Occasional overexploitations of local populations of Achillea are compensated by the capacity to move to other host species. In C. rubiginosa, a species with a host range restricted to the Cardueae, the main larval feeding activity is postponed to a period when the nitrogen content of the host leaves had dropped to 50% of its initial value, but when host plant biomass had increased by 30%. In the monophagous O. luctuosa the larval development is synchronized with a still later phase of host phenology, at which the nitrogen content is below 50% but plant biomass has reached its maximum. There seem to be selection factors, which oppose the use of high quality food in spring and which force the latter two species to postpone their larval development to a later time in the year. This could be caused by numerous factors like, for example, mean daytime temperature. Later in the season the larvae have to cope with the low quality of their host plants. They have, however, the advantage of large quantities of food available.A laboratory study with adults and mature larvae of O. luctuosa shows that this species can overcome low levels of protein nitrogen either by selecting younger leaves with higher nitrogen concentrations or by increasing the daily food consumption rate (RCR) on leaves with a low level of nitrogen and by a prolongation of the feeding period. In this way the larvae compensate the effect of lower daily growth rates (RGR) and a lower food conversion index (ECI) on poor food quality: Regardless of the level of protein nitrogen there was no statistically significant difference in total gain of weight during the third‐instar feeding period and in the weight at the end of the third larval stage. The three investigated chrysomelids show that there exists a broad spectrum of adaptations to overcome the dilemma of variable food quality.
The biology of Penthaleus species in southeastern Australia
Authors: Weeks Andrew R. , Hoffmann Ary A. 
Published: October 2003

AbstractEarth mites are major pests of pastures and crops within southern Australia. While the biology and ecology of the redlegged earth mite (Halotydeus destructor) have been studied extensively, the blue oat mite (Penthaleus major) and its recently discovered relative, Penthaleus falcatus, have received little attention. The distribution of H. destructor, P. major and P. falcatus is described in Victoria, Australia, and the inland borders in central New South Wales are re‐described. A new undescribed Penthaleus species identified from mallee samples is recognized, and its restricted distribution in Victoria is mapped. Electrophoretic data and the complete absence of males indicate that all Penthaleus species are obligate thelytokous parthenogens. The three Penthaleus species differ in clonal diversity. All species are pests of pastures and/or crops, however the preferred plant hosts of P. major and P. falcatus differ. Tolerance of a commonly used pesticide (omethoate) differs between the species. P. falcatus shows the highest LC50, and may be responsible for pesticide control failures. Rearing methods for P. major and P. falcatus are described. The large differences between these blue oat mite species point to difficulties in interpreting early published data that failed to distinguish them.
Compensatory responses of Samea multiplicalis larvae when fed leaves of different fertilization levels of the aquatic weed Pistia stratiotes
Authors: Wheeler G.S. , Halpern M.D. 
Published: October 2003

AbstractCompensatory responses of caterpillars fed low quality food include increased consumption and utilization of essential nutrients. Information about an insect's responses to nutritional challenges from their host plants could benefit weed biological control efforts in the selection and establishment of new agents. The target weed, Pistia stratiotes L. (Araceae) is a floating aquatic plant that has relatively low nitrogen levels which are further diluted with high water content. Efforts to establish the insect Spodoptera pectinicornis (Hampson) (Lepidoptera: Noctuidae) for biological control of P. stratiotes could benefit by examining the nutritional responses of a similar widely established lepidopteran species, Samea multiplicalis (Guenèe) (Lepidoptera: Pyralidae). Larvae of this species were fed leaves of P. stratiotes plants that had been fertilized (NPK) at high and low rates. The leaves of the fertilized plants had a 4.3‐fold increase in nitrogen (dry weight) and a 1.6‐fold increase in water content. The results suggest that no compensatory increases occurred in larvae fed leaves from the low fertilized plants as no changes were found in fresh mass consumption or nitrogen utilization efficiency. Consequently, development time from second‐third instars to pupation was delayed about 3 days compared with larvae fed the high nitrogen leaves. Furthermore, consumption of nitrogen was only 30% and its accumulation into larval tissues was only 60% compared with the larvae fed the high fertilized leaves. The resulting larvae had both a final biomass and a growth rate that were reduced by 40%. Regardless of plant fertilizer level, the larvae fed at a rate 5–10 times greater than that of similar lepidopteran species consuming either low or high quality diets, suggesting that the S. multiplicalis larvae may be functioning at their biological limit for ingesting food.
The efficiency of artificial wingbeat sounds for capturing midges in black light traps
Authors: Hirabayashi Kimio , Ogawa Ken‐ichi 
Published: October 2003

AbstractThis study was conducted to develop a new method to control adult Chironomus plumosus (L.) midges (Diptera: Chironomidae) using their acoustic responses to sound + light traps in the field. Trials were conducted from June 10 to June 27, 1996 near the hyper‐eutrophic Lake Suwa in central Japan. In cylindrical sound traps, optimal trapping of swarming males occurred at frequencies of 270–300 Hz at 22.5 °C. This effect was significantly enhanced using a sound trap equipped with a black light lamp. The mean number of midges captured by sound + light trap was about 4.5 times the number of midges caught by either light or sound trap alone. In conclusion, the application of audio‐frequency sounds combined with attraction to light for chironomid midge control seems to be quite feasible, assuming the availability of a suitable collecting device.
Parasitoid size as a function of host sex: potential for different sex allocation strategies
Authors: Kraaijeveld Alex R. , Adriaanse Irma C.T. , van, den Bergh Bert 
Published: October 2003

AbstractParasitoid females are known to preferentially allocate female eggs to hosts with the higher resource value, usually leading to oviposition of female eggs in larger hosts and male eggs in smaller hosts. For koinobiont parasitoids, if male and female hosts are of equal size at time of oviposition, but differ in size in later developmental stages, the sex of the host could be used to indicate future resource value. Using parasitoids of the braconid genus Asobara, which are larval parasitoids of Drosophila, it is shown that parasitoids emerging from female hosts are larger than those from male hosts. Given this difference in resource value, ovipositing females should preferentially allocate female eggs to female hosts. An alternative strategy would be to decrease the difference in resource value between male and female hosts by castrating male hosts. The primary sex ratio of A. tabida in their two main host species does not differ between male and female hosts. In contrast to A. tabida, A. citri is known to partially castrate male hosts, but this does not decrease the size difference between male and female hosts. As in A. tabida, there is no difference in sex allocation to male and female hosts in A. citri. Despite the clear difference between the resource value of male and female hosts, these parasitoid species do not seem to make optimal use of this difference. They may not be able to discriminate between host sexes or, alternatively, there is a presently unknown fitness disadvantage to ovipositing in female hosts.
Respiration in bumblebee queens: effect of life phase on the discontinuous ventilation cycle
Authors: Beekman M. , van Stratum P. 
Published: October 2003

AbstractEvidence for discontinuous ventilation cycles (DVC) has been obtained for many insects under various experimental conditions. Here, we show that DVC‘s exist for queens of the bumblebee Bombus terrestris in different phases of their life cycle: before entering diapause (pre‐diapause queens) and when a colony has been established (post‐diapause queens). Pre‐ and post‐diapause queens experience distinct environmental conditions (ambient O2 and CO2 concentrations) which is reflected in their DVC: both ventilation frequency and amount of carbon dioxide emitted change with differences in ambient CO2 concentration.
Analysis of resistance in tomato and sweet pepper against the greenhouse whitefly using electrically monitored and visually observed probing and feeding behaviour
Authors: Lei H. , van Lenteren J.C. , Tjallingii W.F. 
Published: October 2003

AbstractDifferent types of plant resistance against the greenhouse whitefly, Trialeurodes vaporariorum, were distinguished according to the tissue location of the resistance factors. The effects of resistance factors were compared by measuring the electrically monitored and visually observed probing and feeding behaviour of whiteflies on two resistant tomato genotypes (82207 and 82216), a susceptible tomato cultivar, and a non‐host plant, sweet pepper. On sweet pepper, whiteflies displayed very short first probes, very long pathway probing and spent much time on non‐feeding activities such as walking and standing still. Also, a high percentage of whiteflies rejected sweet pepper without ingesting substances from the phloem vessel. These data suggest a strong resistance that is based on the factors present in surface/epidermis and/or mesophyll layers of this plant. The behaviour of whiteflies on tomato 82207 was very different from that on sweet pepper. On tomato 82207 whiteflies apparently did not perceive resistance factors on the leaf surface and in the mesophyll. Resistance factors appeared to be present in the phloem tissue, because a higher number of phloem phases, longer phloem salivation periods and shorter phloem ingestion periods were observed when compared with the susceptible tomato cultivar. Tomato 82216 showed no clear resistance factor in the phloem. The importance of combined EPG and behavioural research for host‐plant resistance studies are discussed.
Genetic population structure of the German cockroach, Blattella germanica: Absence of geographical variation
Authors: Cloarec A. , Rivault C. , Cariou M.L. 
Published: October 2003

AbstractThe genetic structure of 31 populations of the German cockroach, Blattella germanica (L.), located in two French cities 900 km apart, was estimated by enzyme gel electrophoresis. A set of 41 loci was analysed. Eight loci (4 Est, 3 Lap and 1 Got) were polymorphic. Diversity was estimated at different geographical levels: the overall population, between cities and within a city. Hierarchical F‐statistics indicated significant genetic differentiation between all populations and among populations within each city, but no differentiation between cities. FST values for populations within each city and for the overall sample were substantially dissimilar. In addition, a cluster analysis did not separate populations according to their geographical origin but according to the predominance of either of the two alternative Est‐4 alleles. The results of this analysis point to the absence of genetic differentiation on a large geographical scale: no large‐scale geographical distance effect was detected. However, we evidenced strong genetic substructuring on a local scale, within cities.
The diapause syndrome in the seed‐eating caterpillar of Coleophora alticolella
Authors: Butterfield J. , Telfer G. , Fielding C. , Coulson J.C. 
Published: October 2003

AbstractAdult emergence in Coleophora alticolella held at 15 °C was accelerated by exposure to L18:D6 in autumn and midwinter. The effect decreased during winter and exposure of individuals, held at low temperature over winter, to L18:D6 or L6:D18 at 15 °C at the end of March resulted in the same mean emergence date. Long daylength experienced at 5 °C did not promote emergence nor did exposure to low temperature during winter. The number of adults emerging increased with the length of time cultures were held on short day but was always below 50% of the larvae. When larvae were exposed to L18:D6 and L6:D18 at 15 °C at the end of March, on long day 61% adults emerged and 39% remained in diapause, whereas on short day, 25% became adult and 75% remained diapausing larvae. The possibility of cohort splitting, with some individuals undergoing prolonged diapause, is discussed.
Nonsteroidal moulting hormone agonists: effects on protein synthesis and cuticle formation in Colorado potato beetle larvae
Authors: Smagghe Guy , Viñuela Elisa , Van Limbergen Heidi , Budia Flor , Tirry Luc 
Published: October 2003

AbstractLarvae of the Colorado potato beetle, Leptinotarsa decemlineata (Say), that were orally treated with RH‐0345 at 0.1 mg l−1, RH‐5849 at 10 and 50 mg l−1, tebufenozide at 2 g l−1, and 20‐hydroxyecdysone at 2 g l−1, showed symptoms of premature moulting, followed by inhibition of ecdysis. In addition, fresh weight gain and total protein content were blocked. The effects on haemolymphal and cuticular polypeptides after PAGE were linked with premature, new epicuticle deposition as was observed under the electron microscope. These observations support the concept that the ecdysteroid‐mimicking action of the three nonsteroidal molecules is specific.
Effect of cannibalism and predation on the larval performance of two ladybird beetles
Authors: Yasuda Hironori , Ohnuma Nao 
Published: October 2003

AbstractThe relative impact of cannibalism and predation on the development and survival of fourth instar larvae was assessed in two species of aphidophagous ladybird beetles, Coccinella septempunctata and Harmonia axyridis. The effect of eating aphids, conspecific larvae or heterospecific larvae on larval performance differed in the two species: aphids were the best food for C. septempunctata and survival of C. septempunctata larvae was significantly lower when offered heterospecific larvae rather than conspecific larvae or aphids as food, indicating that H. axyridis larvae were not suitable food for C. septempunctata. However, as the different foods did not affect the larval performance of H. axyridis, this species appears to be more polyphagous. Both intraguild predation by the aggressive larvae of H. axyridis and the polyphagous food habit of this species may account for its dominance in ladybird assemblages and its displacing other ladybird beetles in several places in the world.
Selection for non‐diapause in the bumblebee Bombus terrestris, with notes on the effect of inbreeding
Authors: Beekman M. , van Stratum P. , Veerman A. 
Published: October 2003

AbstractBumblebees are generally believed to be annual insects. However, here we will show that under laboratory conditions the bumblebee Bombus terrestris (L.) can produce a second generation without a period of cold storage (diapause) or CO2 narcosis (a method to break diapause). It is also shown that this so‐called non‐diapause trait can be selected for. The percentage of non‐diapausing queens increased from 8% (minimum) to 97% (maximum) in two generations of selection. However, it was not possible to maintain isofemale non‐diapause lines. Colonies of the fourth and fifth generation remained small (expressed in worker number) and produced a small number of queens. Also the percentage of queens that started laying eggs (defined as the percentage non‐diapause) decreased in the fourth and fifth generations. To study whether this decline of the non‐diapause lines was caused by inbreeding, a control experiment was conducted. In this control experiment queens were mated with their brothers (full‐sib mating) for several generations and the number of queens that start egg laying was measured. This revealed that inbreeding can have a negative effect on the egg‐laying capacities of queens thus causing the decline of inbred (non‐diapause) lines.
Deathwatch beetle, Xestobium rufovillosum, in historical buildings: monitoring the pest and its predators
Authors: Belmain S.R. , Simmonds M.S.J. , Blaney W.M. 
Published: October 2003

AbstractTrapping and monitoring experiments were conducted in the roof spaces of four buildings infested with deathwatch beetle, Xestobium rufovillosum de Geer (Coleoptera: Anobiidae). Data from sticky traps and an ultra‐violet insectocutor showed that adult deathwatch beetles were trapped from May to July. The beetles were attracted to natural and UV light, and more beetles were caught on white coloured traps than yellow, blue or red traps. Deathwatch beetles comprised 30–40% of all arthropods caught. The weekly trap catch of all arthropods, including deathwatch beetle, was positively correlated with ambient temperature. Adult beetles flew in buildings at ambient temperatures greater than 17 °C. Arthropods caught in the buildings were categorised as resident, over‐wintering or non‐resident arthropods. Predatory spiders comprised 13% of arthropods caught and the predatory beetle, Korynetes caeruleus de Geer, was found in all four buildings. There was no evidence of other predators or parasitoids of the deathwatch beetle
Host‐plant specificity limits the geographic distribution of thistle feeding ladybird beetles
Authors: Koizumi Tatsuya , Fujiyama Naoyuki , Katakura Haruo 
Published: October 2003

AbstractThe relationships between two phytophagous ladybird beetle species, Epilachna pustulosa Kôno and E. niponica Lewis (Coleoptera, Coccinellidae), and their main host plants, thistles (Cirsium spp., Asteraceae) were investigated in Oshima Peninsula, southern Hokkaido, northern Japan. Epilachna pustulosa was found feeding on Cirsium kamtschaticum in the northernmost part of the peninsula, whereas E. niponica was confined to the Ohno Plain and adjacent areas in the southernmost part, and occurred mainly on C. alpicola. No thistle feeding epilachnines were found in the middle part of the peninsula despite the abundance of another thistle species, C. grayanum. Both beetle species showed lower adult preference and reduced growth performance on C. grayanum compared to their respective host plants under laboratory conditions. We concluded that the distribution of thistle feeding epilachnines in Oshima Peninsula was principally determined by the availability of appropriate host plants.
Factors affecting ovipositor probing in Trybliographa rapae, a parasitoid of the cabbage root fly
Authors: Brown P.E. , Anderson M. 
Published: October 2003

AbstractThe effect of allelochemicals from its host, the larva of the cabbage root fly, Delia radicum (L.) (Diptera: Anthomyiidae), and the host‘s food plant on the ovipositor probing response of the parasitoid Trybliographa rapae (Westw.) (Hymenoptera: Cynipidae) were investigated. Trybliographa rapae probed both cabbage root fly infested and uninfested swede (Brassica napus var. napobrassica), although significantly more wasps responded to infested swede. Antennal sensilla are likely to be the mediators of this response. The synomones and kairomones involved are extractable in water, diethyl ether and methanol. No response was observed to washed, starved cabbage root fly larvae. Wasps spent significantly longer searching infested swede than uninfested, although probing frequency remained constant. It is suggested that the initiation of probing in T. rapae is dependent on a threshold concentration of general synomones or host related synomones and kairomones, whereas time spent searching a particular area is dependent on the environment perceived by sensilla on the ovipositor.
Life table characteristics of Macrolophus caliginosus preying upon Tetranychus urticae
Authors: Hansen Dorthe L. , Brødsgaard Henrik F. , Enkegaard Annie 
Published: October 2003

AbstractThe life table characteristics of the polyphagous mirid Macrolophus caliginosus Wagner (Heteroptera: Miridae) preying on various stages of Tetranychus urticae Koch (Acari: Tetranychidae) with tomato as host plant were described at 22 °C. The following average parameters were obtained: Female longevity: 28.7 days; fecundity: 0.7 eggs/female/day; egg mortality: 2.6%; pre‐oviposition period: 5.5 days; oviposition period: 18.1 days; post‐oviposition period: 3.2 days; juvenile development time: 26.8 days; juvenile mortality: 34.9%; and sex ratio (♀/(♀+♂)) 0.46. Life table parameters were estimated as net reproduction rate (R0): 6.15; intrinsic rate of increase (rm): 0.031 day−1; finite rate of increase (≤): 1.032; mean generation time (Tc): 58.17 days; and doubling time (T2) 22.2 days. The parameters obtained were in accordance with those reported for M. caliginosus fed on another mite species (T. turkestani Ugarov & Nikolski (Acari: Tetranychidae)). However, compared to the performance of M. caliginosus fed on common glasshouse insect pests, a diet consisting of only mites appeared to be inferior. However, being a voracious predator, M. caliginosus may be a valuable addition to existing methods of mite control.
The spatial and temporal distribution of the grain aphid Sitobion avenae in winter wheat
Authors: Winder L. , Perry J.N. , Holland J.M. 
Published: October 2003

AbstractThe spatial and temporal distribution of the grain aphid Sitobion avenae F. (Homoptera: Aphididae) was studied within a field of winter wheat during the summer of 1996. Sampling was done using four nested grids comprising 133 locations. Analysis by Taylor's power law gave results typical for insect populations. Analysis by SADIE (Spatial Analysis by Distance Indices) showed spatial pattern due to edge effects and sampling scale, and positive but mild spatial association, although spatial patterns were ephemeral. Reasons for these findings and the implications for integrated crop management are discussed.