bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geographical variation in female sex pheromones of the rice leaffolder moth, Cnaphalocrocis medinalis: identification of pheromone components in Japan
Authors: Kawazu Kei , Hasegawa Jun‐ichi , Honda Hiroshi , Ishikawa Yukio , Wakamura Sadao , Sugie Hajime , Kamiwada Hidemi , Kamimuro Takeshi , Yoshiyasu Yukata , Tatsuki Sadahiro 
Published: October 2003

AbstractSex pheromone components of the Japanese rice leaffolder moth, Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) were identified from ovipositor extracts of virgin females as (Z)‐11‐octadecenal, (Z)‐13‐octadecenal, (Z)‐11‐octadecen‐1‐ol and (Z)‐13‐octadecen‐1‐ol at a ratio of 11:100:24:36 by GC‐EAD, GC, GC‐MS. The total amount was estimated to be ca.0.9 ng/female. Field bioassays in Kagoshima, Japan, showed that the two aldehydes are essential for male attraction and the alcohols may have a synergistic effect on the aldehydes. A rubber septum containing 0.9 mg of the four components at the natural ratio was shown to be an effective lure for monitoring this pest in Japan. The above four components are quite different from the sex pheromone components reported previously for the same species of either Philippine or Indian origin; components were shown to be (Z)‐11‐hexadecenyl acetate and (Z)‐13‐octadecenyl acetate at a ratio of 98:2 in the Philippine blend and 1:10 in the Indian blend. Furthermore, in the field tests in Japan, neither the Philippine blend nor the Indian blend showed any attractive activity, while the Japanese blend attracted significant numbers of male moths. These results suggest that there are remarkable geographical variations in the sex pheromone composition of this species or there are several distinct species using different sex pheromone blends.
Influence of thrips prey species on the life‐history and behaviour of Orius albidipennis
Authors: Fritsche Maria Elena , Tamò Manuele 
Published: October 2003

AbstractThe effects of two diets, i.e., cowpea leaves plus Megalurothrips sjostedti larvae versus cowpea leaves alone, on nymphal development and mortality of Orius albidipennis were studied under controlled laboratory conditions in Benin, West Africa. Nymphal development was longer when O. albidipennis was fed with cowpea leaves only, compared to the diet complemented with M. sjostedti larvae (17.6 days versus 14.8, respectively). Nymphal mortality was very high (78.6%) if fed with cowpea leaves only, and still relatively high if the diet was complemented with thrips larvae (44.4%).In a separate study on the longevity and fecundity of O. albidipennis adult females feeding on M. sjostedti larvae, an average of 6.8 eggs per day (maximum 16 eggs) and a mean total fecundity of 61.1 eggs were observed. The females lived on average 13.5 days.Finally, observations on the predation by O. albidipennis adults on three different thrips species revealed that M. sjostedti larvae were killed at a lower rate than larvae of Ceratothripoides cameroni and Frankliniella schultzei. Higher predation rates were measured using unmated females and males than in mated females. However, the rate of first attack, measured as first larva attacked in dual‐choice assays, was higher for M. sjostedti when a F. schultzei larva was offered simultaneously, and not different when a C. cameroni or Sericothrips adolfifriderici larva was offered.The results of this study are discussed with regard to the lack of efficacy of O. albidipennis as biological control agent for M. sjostedti.
Odour sensitivity of antennal olfactory cells underlying grooved pegs of Anopheles gambiae s.s. and An. quadriannulatus
Authors: van, den Broek Ingrid V.F. , den Otter C.J. 
Published: October 2003

AbstractIn female mosquitoes of the anthropophilic species Anopheles gambiae Giles s.s. and the zoophilic An. quadriannulatus Theobald single sensillum recordings from grooved pegs were made. In both species, the majority of these sensilla responded to ammonium hydroxide, butylamine and propanoic acid, whereas a smaller part responded to acetone. Lactic acid, butanone, 3‐methyl phenol and 1‐octen‐3‐ol evoked responses in a minority of grooved pegs only. In An. gambiae these four substances evoked either excitatory or inhibitory responses. In An. quadriannulatus excitatory and inhibitory responses were only found on stimulation with lactic acid; butanone, 3‐methyl phenol and 1‐octen‐3‐ol only evoked inhibition in the pegs of this species. More than half of the grooved pegs responded to water vapour with an increase in spike frequency. As opposed to this, in some pegs inhibitory responses were found upon stimulation with vapour of low humidity. This suggests that grooved pegs may play a role in humidity perception in Anopheles. Dose‐response relations were investigated for cells excited by ammonium hydroxide, butylamine and propanoic acid. Excitatory responses to these three substances were dose‐dependent. No significant differences were found between the dose‐response curves of the two species. It is concluded that in both species the host odours tested are not perceived by specialist cells. Combined information from generalist cells may provide a detailed ‘odour profile’ of the host.
Local and distant prey‐related cues influence when an acarine predator leaves a prey patch
Authors: Mayland Holly , Margolies David C. , Charlton Ralph E. 
Published: October 2003

AbstractOver relatively long distances, the predatory mite Phytoseiulus persimilis is able to detect volatiles produced by bean plants that are infested by its prey, Tetranychus urticae, the twospotted spider mite. Our investigation examined the separate and combined effects of prey, their products, and prey‐induced plant volatiles on when P. persimilis left a potential prey host plant. In wind tunnels, we assessed the relative importance of and interaction among local and distant prey‐related cues. The examination of local cues included: (1) all local cues (prey eggs, webbing, and prey‐induced plant volatiles), (2) food (prey eggs) and webbing only, (3) plant volatiles only, and (4) no prey‐related cues. The examination of distant cues involved the presence or absence of prey‐induced plant volatiles from upwind plants. External volatile cues, produced by placing prey‐infested plants upwind in the wind tunnel, resulted in more predators leaving downwind plants, and leaving sooner, than when clean plants were upwind, regardless of the availability of prey or prey‐related cues on the local plant. However, local cues, especially the presence of food/webbing, had a greater effect than distant cues on timing of predator leaving. Predators remained in larger numbers and for longer times on prey‐infested plants. However, the presence of either locally‐produced plant volatiles or food/webbing alone still reduced the number of predators leaving a plant in the first hour compared to clean plants. After the first hour, the number of predators leaving was primarily driven by the presence of food/webbing. When no food/webbing was available, predators left plants rapidly; if food/webbing was available, some predatory mites remained on plants at least 24 hours. Even if no food/webbing was available, predators presented with local volatiles remained on plants for several hours longer than on clean plants without local volatiles. These small changes in leaving rates may lead to differences in local population dynamics, and possibly regional persistence, of the predator‐prey interaction in patchy environments.
Spruce stands provide natural food sources to adult hymenopteran parasitoids of bark beetles
Authors: Hougardy E. , Grégoire J.‐C. 
Published: October 2003

AbstractAdults of synovigenic hymenopteran parasitoids of bark beetles need supplemental feeding to maximise their lifetime realised fecundity, and yet little is known about the natural sources that provide this food. Here we show that, in spite of the reduced diversity of flowering plants expected in even‐aged spruce plantations, several plant species are present that might provide nectar and pollen to the hymenopteran parasitoid complex of Ips typographus L. (Coleoptera: Scolytidae), throughout the growing season. Conifer aphids are also abundant in these stands and produce large amounts of honeydew, which might also be consumed by the parasitoids. Laboratory experiments demonstrate that longevity is significantly increased in Coeloides bostrychorum Giraud (Hymenoptera: Braconidae) when the wasps are exposed to flowers of various species commonly found in spruce stands.
Female‐derived sex pheromone mediates courtship behaviour in the parasitoid Lariophagus distinguendus
Authors: Ruther Joachim , Homann Marion , Steidle Johannes L.M. 
Published: October 2003

AbstractCourtship behaviour of the polyphagous ectoparasitoid Lariophagus distinguendus Först. (Hymenoptera, Pteromalidae) was studied. The initial behavioural element of the courtship sequence is a characteristic wing fanning shown by the males at encounters with females. Wing fanning and arrestment of the males was elicited by paper discs treated with dichloromethane extracts from virgin females showing the existence of a female‐derived sex pheromone. The pheromone is only active at a distance between 0–5 mm suggesting low volatility of the active compound(s). Females mate only once, and the pheromone is still perceived by males at least 5 days after female mating. Males exposed to dissected female heads, thoraces and abdomens, showed wing fanning towards all segments. However, extracts from female abdomens were significantly more active than those from heads or thoraces suggesting the pheromone source to be located in the abdomen.
Fitness costs of resistance to Bacillus thuringiensis in the Indianmeal moth, Plodia interpunctella
Authors: Oppert Brenda , Hammel Richard , Throne James E. , Kramer Karl J. 
Published: October 2003

AbstractGenetic changes in insects that result in insecticide resistance can also affect their fitness. Here, we report measurements of development time and survival of the Indianmeal moth, Plodia interpunctella (Hübner), to compare the relative fitness of Bacillus thuringiensis (Bt)‐susceptible and ‐resistant colonies. Measurements of larval development time and survival indicated that a fitness cost was associated with resistance to Bt in some Bt‐resistant colonies but not others. Comparisons of geographically different populations revealed inherent differences in development time and survival. In most cases, Bt‐resistant moths suffered no disadvantage when feeding on a Bt‐treated diet. In many cases, the development of Bt‐resistant moths on Bt‐treated diet was slower than the unselected moths on untreated diet, but it is unclear whether these differences would affect the successful mating of susceptible and resistant moths.
Butterfly nectaring flowers: butterfly morphology and flower form
Authors: Corbet Sarah A. 
Published: October 2003

AbstractThe profitability of butterfly foraging depends in part on the corolla depth and clustering of flowers, and the tongue length, body mass and wing loading of butterflies. Interactions among these attributes of flowers and butterflies were investigated, using data from a field study in Cornwall and from Porter et al. (1992). The maximum corolla depth from which a butterfly can feed depends on tongue length, which correlates with the more easily measured attributes of body mass and wing loading. Small, short‐tongued butterflies did not visit deep flowers. The quantity of nectar sugar per flower necessary for profitable foraging depends on foraging costs, which are expected to correlate with wing loading. Butterfly species with a high wing loading generally confined their visits to flowers that were clustered or very nectar‐rich. Butterfly species with a low wing loading included solitary and less nectar‐rich flowers in their diet. Body mass and wing loading affect a butterfly's load‐carrying capacity (limiting the distance between fuelling stops) and cooling rate (limiting the distance between stops for basking or endothermic warming), and will therefore influence the capacity for floral selectivity and for migration and dispersal. Body mass, wing loading and tongue length characterised families or subfamilies of butterflies. For example vanessine nymphalids, with their long tongues and high wing loading, visited the deep, massed flowers of Buddleja davidii, but lycaenids, with their short tongues and low wing loading, did not. These often visited members of the Asteraceae. Eupatorium cannabinum, with massed flowers offering abundant and accessible nectar, was visited by butterflies of all tongue lengths and both high and low wing loading. These findings may help to inform habitat management for butterfly nectaring flowers.
Pre‐ and post‐landing response of the parasitoid Encarsia formosa to whitefly hosts on Gerbera jamesonii
Authors: Sütterlin S. , van Lenteren J.C. 
Published: October 2003

AbstractOne of the factors that may complicate biological control of the greenhouse whitefly on Gerbera jamesonii by Encarsia formosa is the rosette shape of this ornamental, which differs from the vertical shape of most vegetable plants (cucumber, egg plant, tomato, etc.). Therefore, host‐habitat location and the behaviour prior to landing on uninfested and infested leaves was studied. Attraction of E. formosa from a short distance by infested leaves could not be detected: the parasitoid females landed at random on uninfested and infested leaves. After the first landing, a redistribution of the wasps occurred on the leaves. After 24 h three times as many wasps were found on the infested leaves than on uninfested ones. In a dispersal experiment with four plants, E. formosa appeared to have no preference for landing on leaves of the medium age class, which is the age class on which most of the whiteflies in a suitable stage for parasitism occur. Twenty percent of the parasitoids were found on the plants 20 min after releasing them. These results were independent of the plant cultivar and the host density on the plants. In the course of 8 h, the number of E. formosa females recovered from plants increased linearly, and this increase was greater on plants where hosts were present and also greater on the plant cultivar with the lowest trichome density. After 24 h, the percentage of females was highest (56%) on plants with the highest host density. E. formosa females were arrested on leaves where hosts were present. Contrary to our expectation, the results from the two G. jamesonii cultivars that differed strongly in leaf hairiness were not significantly different in most experiments. Only at the high host density was parasitism found to be lower on the cultivar with the higher hair density. Parasitoids may walk on top of the ‘hair coverlet’ of cultivars with high trichome density and, therefore, be hampered less than expected.
Diapause induction in aphid parasitoids
Authors: Polgár L.A. , Hardie Jim 
Published: October 2003

AbstractDiapause is one of the adaptations that insects have evolved for the synchronisation of their life cycle with seasonal climatic changes and resources. In aphid parasitoids, univoltine species have an obligatory, genetically determined diapause. Polyvoltine species, on the other hand, use a variety of abiotic (temperature, photoperiod) and biotic (host insect or/and host plant) signals for the induction of diapause. We present an overview of the role of these environmental cues in diapause induction in specialist and generalist aphid parasitoids, and discuss possible endocrine factors that may be involved in diapause induction.
Individual behaviour and population dynamics: lessons from aphid parasitoids
Authors: Mondor Edward B. , Roitberg Bernard D. 
Published: October 2003

AbstractAn increasing number of researchers are studying behaviour in the hopes of understanding population dynamics or improving biological control efforts of insect pests by natural enemies. However, it is unclear exactly how behavioural studies will improve our understanding of these population level processes. In this paper we argue that in order to understand population level processes, the problem must be approached from a population biology perspective. A comprehensive understanding of certain behaviours will provide little towards our understanding of host‐natural enemy interactions. For example, using an aphid‐parasitoid model, we examined the effect that a commonly studied behaviour, variance in host selection by aphid parasitoids, has on aphid‐parasitoid population dynamics. Differential host selection does not qualitatively alter classic Nicholson‐Bailey dynamics, but only results in quantitative differences in aphid‐parasitoid population sizes. Irrespective of the degree of aphid instar preference, a large increase in the number of aphids is followed by a large increase in the number of parasitoids, decimating the aphid population. Thus, studying some behaviours, such as variance in host selection, will not contribute substantially to an understanding of aphid‐parasitoid population dynamics.
Understanding insect endocrine systems: molecular approaches*
Authors: Lafont René 
Published: October 2003

AbstractMolecular approaches have led to spectacular improvement of our knowledge of insect endocrinology. The present review focuses on two major classes of insect lipidic hormones, ecdysteroids and juvenile hormones. Although the ecdysteroid biosynthetic pathway is not yet fully elucidated, several new steps have been recently characterized, and molecular studies of biosynthetic enzymes are now beginning. It is expected that, thanks to suitable biological models (e.g., ecdysteroid‐defective mutants of Drosophila), the entire biosynthetic pathway will be elucidated in the near future. The understanding of the ecdysteroid mode of action has benefited from studies with Drosophila and major developments relate to the cascades of gene activation and the molecular basis for the stage‐ and tissue‐specificity of hormonal effects. The biosynthetic pathway of juvenile hormones is fully known, but molecular studies of enzymes are still in their infancy, and there is some controversy about the nature of juvenile hormone receptors. Within the forthcoming years, molecular tools will allow to characterize all the enzymes involved in hormone biosynthesis and then to analyze the fine regulation of hormone titers. They will also allow comparative studies aimed at investigating the presence of related molecules (hormone biosynthetic enzymes and receptors) among other Invertebrates (Arthropods and non‐Arthropods), and thus to propose evolutionary scenarios for their endocrine systems.
Effects of host age on parasitism and progeny allocation in Trichogrammatidae
Authors: Godin Claude , Boivin Guy 
Published: October 2003

AbstractThe impact of host age on the number of hosts killed, survival of progeny, progeny allocation, and sex allocation was examined for several Trichogrammatidae (Hymenoptera) species in laboratory choice tests. Individual female parasitoids were provided with young, medium‐aged and old eggs of one of three lepidopterous host species: Trichoplusia ni (Hübner) (Noctuidae), Pieris rapae (L.) (Pieridae), or Plutella xylostella (L.) (Plutellidae). Trichogrammatid species behaved as gregarious parasitoids with the first two host species, and as solitary parasitoids with eggs of the smaller latter one. They mostly preferred young eggs of T. ni, but did not discriminate among P. rapae eggs of different ages, and often preferred young or medium‐aged P. xylostella eggs over old eggs. Survival of progeny did not vary constantly with host age, although it was often very low in P. rapae eggs of any age. Clutch size frequently decreased with host age in both T. ni and P. rapae. Offspring sex ratio did not change with age of T. ni and P. rapae eggs, and rarely did so in P. xylostella eggs. In regard to host age, the results with T. ni are the ones which are the most in agreement with optimal foraging theoretical predictions, as clutch size was the highest in preferred younger eggs.
Electrical Penetration Graph analysis reveals population differentiation of host‐plant probing behaviors within the aphid species Uroleucon ambrosiae
Authors: Bernays Elizabeth A. , Funk Daniel J. 
Published: October 2003

Abstract Uroleucon ambrosiae collected from the eastern and the southwestern United States were studied in relation to host‐plant probing. In the field, eastern aphids are highly specific on Ambrosia trifida, while southwestern aphids feed on Ambrosia trifida plus many other species in the family Asteraceae. Electrical penetration graphs of insects on the principal host, A. trifida, and an additional host of southwestern populations, Heterotheca subaxillaris, revealed regional differentiation in host‐associated aphid behaviors, specifically in the first phase of subcuticular probing, and in phloem finding activities. Eastern aphids used A. trifida more efficiently than southwestern aphids, but were demonstrably less vigorous in their probing activities on H. subaxillaris.
Difficulties in location and acceptance of phloem sap combined with reduced concentration of phloem amino acids explain lowered performance of the aphid Rhopalosiphum padi on nitrogen deficient barley (Hordeum vulgare) seedlings
Authors: Ponder K.L. , Pritchard J. , Harrington R. , Bale J.S. 
Published: October 2003

AbstractEffects of nitrogen deficiency in hydroponically grown barley seedlings (Hordeum vulgare L.) on the development and reproduction of the aphid Rhopalosiphum padi (L.) (Hemiptera: Aphididae) were investigated.Plant growth was significantly reduced in seedlings grown without nitrogen. Aphid intrinsic rate of increase (rm) was also significantly lower on these plants compared with that on plants grown with 8 mol m−3 nitrogen. Phloem sap was collected from seedling stems by aphid stylectomy and amino acids quantified by HPLC. There was a significant reduction in the concentration of non‐essential amino acids as a group, but not of essential amino acids. Electrical penetration graphs (EPG) indicated that aphids reached the phloem more quickly and fed for longer on plants grown with nitrogen. This is the first reported study in which this combination of techniques has been used to understand the interactions of an aphid and plant under different environmental conditions.
Local enhancement of arrivals of Ceratitis capitata females on fruit mimics
Authors: Prokopy Ronald J. , Miller Neil W. , Duan Jian J. , Vargas Roger I. 
Published: October 2003

AbstractMature female Mediterranean fruit flies, Ceratitis capitata (Wiedemann), isolated from conspecifics for 7 days prior to testing in laboratory cages, were attracted to yellow plastic fruit‐mimicking hemispheres or spheres in significantly greater numbers when groups of conspecific females were present than absent on fruit mimics. Attraction of females to conspecifics occurred for females deprived of protein or continuously provided with protein since eclosion, for fruit mimics that were unbaited or baited with odor of food or fruit, and under single‐choice as well as multiple‐choice test conditions. Attraction proved just as great to fruit mimics having dead conspecifics as to mimics having live conspecifics, was evident also when fruit mimics were orange or white, and occurred also in response to presence of live Bactrocera dorsalis (Hendel) females on fruit mimics. We discuss our findings in relation to local enhancement, a form of social facilitation in insects and other animals.