bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of learning in related generalist and specialist eucoilid parasitoids
Authors: Simons M. T. T. Poolman , Suverkropp B. P. , Vet L. E. M. , de Moed G.
Published: April 2011

Effects of learning in two microhabitat specialists, Leptopilina boulardi Barbotin et al. and L. fimbriata Kieffer were compared to previous and new results of learning in the microhabitat generalist L. heterotoma Thomson. Females were given one or more oviposition experiences on hosts in different types of substrate. In all species oviposition experience affected the choice for a substrate, although this effect of learning was considerably less in L. fimbriata compared to the other two species. Patch times, known to be highly determined by experience in the generalist L. heterotoma, were much less flexible in the specialists. L. boulardi and L. fimbriata have fixed patch times on their natural substrate and have variable patch times on other substrates only. In all three species one oviposition affected the choice for a substrate. Additional ovipositions showed no different effect. An accumulative effect of the number of ovipositions on patch times was found in L. heterotoma only. Retention of the learning effect was only studied in L. boulardi, and was shown to be similar to that reported for L. heterotoma, i.e. two to three days. Although learning was found in both the generalist and the specialist species studied, it seems to affect their foraging behaviour differently.
Preliminary results on in vitro rearing of the endoparasitoid Cardiochiles nigriceps from egg to second instar
Authors: Pennacchio F. , Vinson S. B. , Tremblay E.
Published: April 2011

The composition of an artificial medium and technical procedures used for in vitro rearing of the endophagous larval parasitoid Cardiochiles nigriceps Viereck (Hymenoptera, Braconidae), from post‐germ band egg to the 2nd instar larva, are described. Amino acids, carbohydrates, salts, and vitamins were supplied in defined amounts as an aqueous solution which, when supplemented with 20 mg/ml of bovine albumin, 5 mg/ml of lactalbumin (enzymatic hydrolysate), 20% (v/v) fetal bovine serum, 20% (v/v) milk and 10% (v/v) chicken egg yolk, allowed for parasitoid growth and molting to the 2nd instar. Molting to the final instar was never observed.
Toxicity of the limonoid allelochemical cedrelone to noctuid larvae
Authors: Koul O. , Isman M. B.
Published: April 2011

The limonoid cedrelone, a constituent of Cedrela toona and C. odorata (Meliaceae) was evaluated as a larval growth inhibitor for the polyphagous noctuids Peridroma saucia and Mamestra configurata by examining its effects on development and feeding behaviour. Cedrelone significantly inhibited growth of different larval instars when administered orally (in artificial diet), topically or via injection. Nutritional analyses revealed that both growth inhibition and reduced consumption are a consequence of post‐ingestive malaise rather than a peripherally‐mediated antifeedant effect. Cedrelone administered via injection to sixth instar P. saucia larvae also inhibited growth, delayed development, and resulted in considerable larval mortality. However, all larvae which survived treatment pupated successfully. The present study suggests that the toxicity of cedrelone does not likely involve the endocrine system.
Intraspecific variation in bionomic characters of the Mexican bean weevil, Zabrotes subfasciatus
Authors: Credland P. F. , Dendy J.
Published: April 2011

Zabrotes subfasciatus (Boheman) (Coleoptera: Bruchidae) is native to parts of Central and South America but has now been spread to many others areas. It commonly infests the seeds of both Lima beans, Phaseolus lunatus, and common beans, Phaseolus vulgaris. Five geographic populations were found to differ in fecundity, patterns of egg distribution, times of development and adult sizes when they were kept under the same conditions. Each population also differed unpredictably from the others in its response to different cultivars of host seed. These differences have been shown to be of considerable importance in determining the potential pest status of the populations and should also promote caution in making predictions about the responses of different populations to new cultivars of bean for agricultural use.
Age related changes in the calling behaviour and the attractiveness of obliquebanded leafroller virgin females, Choristoneura rosaceana, under different constant and fluctuating temperature conditions
Authors: Delisle J.
Published: April 2011

C. rosaceana (Lepidoptera: Tortricidae) virgin females initiated calling in the first scotophase following emergence at both 15° and 20 °C constant temperature under a 16L:8D photoperiod. As females aged, the onset of calling occurred much earlier, and the time spent calling increased significantly at both temperature conditions. For a given age, the onset of calling occurred significantly earlier at 15 °C than at 20 °C, but the duration of calling did not vary with temperature. Similar results were obtained under warm and cold thermocycles that simulated natural conditions prevailing during the summer and fall flight periods. A comparison of the degree of attractancy of different‐aged females (0, 3, and 5 days old) in the field showed that the attractiveness of 0‐day‐old females relative to that of 3‐day old females did not vary between flights. However, compared to day‐5 females, the relative attractiveness of 0‐ and 3‐day‐old females was greater in the summer than in the fall flights. The potential adaptative value of these changes for seasonal mating success are discussed.
Intra‐tree foraging behavior of Dacus dorsalis flies in relation to host fruit quantity, quality and type
Authors: Green T.A. , Prokopy R. J. , Vargas R. I. , Kanehisa D. , Albrecht C.
Published: April 2011

We observed the fruit foraging behavior of mature female oriental fruit flies, Dacus dorsalis Hendel (Diptera, Tephritidae), released individually onto potted field‐caged host trees containing fruit of different quality, quantity, or type (no fruit, 3 or 12 uninfested kumquats, 12 infested kumquats, or 3 uninfested sweet oranges). Our findings were largely consistent with foraging‐behavior theory, and with previous results for Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and the apple maggot fly, Rhagoletis pomonella (Walsh): (1) flies left fruitless trees soon after release, (2) more flies visited fruit, and flies visited more fruit and spent more time on trees with increasing fruit density, and (3) Giving Up Time (time between last oviposition and leaving the tree) was significantly greater for flies visiting infested fruit than for those visiting uninfested fruit. Oriental fruit flies declined to oviposit in fruit containing conspecific larvae.
Influence of temperature and daylength on population development of Aphis gossypii on Cucurbita pepo
Authors: Aldyhim Y. N. , Khalil A. F.
Published: April 2011

The life table parameters of Aphis gossypii Glover were evaluated in tow sets of experiments on Cucurbita pepo. The first set was conducted at six constant temperatures (5 °C increments from 10–35 °C) with 12 h photophase. The second set of experiments was conducted at 6, 12, and 18 h photophase at 25 °C. Nymphal survivorship was 100% at 15, 20, 25 and 30 °C. However, it was 80 and 0% at 10 and 35 °C, respectively. The optimum temperature for body length was 10 °C, and body length decreased with increasing temperature. A. gossypii attained its optimum growth and reproduction at 25 °C. At this temperature, the net reproductive rate (79.7), intrinsic rate of increase (0.496) and finite rate of increase (1.6) were largest while generation time (6.6 d) and population doubling time (1.4 d) were smallest. Temperatures above and below 25 °C reduced the net reproductive rate, and the intrinsic and finite rates of increase. The intrinsic and finite rates of increase of A. gossypii reared at 18 h photophase (0.53 and 1.7) were significantly higher than at 12 (0.43 and 1.5) and 6 h daylength (0.49 and 1.6).
The significance of antioxidants in the aphid‐plant interaction: the redox hypothesis
Authors: Miles P. W. , Oertli J. J.
Published: April 2011

The hypothesis is advanced that a redox system controls oxidation rates during the responses of plants to attack by sucking insects, that soluble antioxidants, such as ascorbate and glutathione, enhance the effectiveness of the plant's defensive system, and that oxidising enzymes in the saliva of aphids (and other phytophagous sucking insects) serve to counter it.

Plants typically respond to wounding, including that caused by sucking insects, by mobilising and oxidising phenolic compounds. The initial phenolic monomers, and especially the monomeric o‐quinones to which many give rise on oxidation, are generally deterrent to insects. Their final oxidation products, however, are polymers and phenol‐protein conjugates, which are non‐toxic, but serve to seal off damaged cells. It is suggested that effective defence by the plant requires oxidation of phenolics at a controlled rate that maintains a deterrent titre of the monomers, while allowing a well ordered deposition of sealants. It is also suggested that the salivary oxidases of the insects hasten oxidation in the affected tissues, thereby decreasing concentrations of monomeric phenols and quinones. It is further suggested that sedentary species may also thereby disorganise the sealing off of affected tissues.

A kinetic model is developed to show that inclusion of a reductive cycle in the sequential oxidation of phenolics increases the steady state concentrations of monomeric phenols for a given throughput. Conversely, an increase in oxidation rates diminishes the titre of monomers for the same throughput.

In initial biological tests of the hypothesis, infiltration of stems of lucerne cultivars with ascorbate or glutathione reduced the reproductive rate of spotted alfalfa aphid, Therioaphis trifolii maculata (Buckton), and of blue‐green aphid, Acyrthosiphon kondo Shinji, feeding thereon. Intrinsically non‐deterrent concentrations of ascorbate synergised the deterrence of the plant phenolics chlorogenic acid and catechin to the apple aphid, Aphis pomi (de Geer), and the spotted alfalfa aphid, T. t. maculata, respectively.
Wind tunnel assays of olfactory responses of female Rhagoletis pomonella flies to apple volatiles: effect of wind speed and odour release rate
Authors: Aluja M. , Prokopy R. J. , Buonaccorsi J. P. , Cardé R. T.
Published: April 2011

The effect of wind speed and odour release rate on female Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) responses to synthetic host apple volatiles was studied in a wind tunnel bioassay. Three apple tree models were placed in the wind tunnel (upwind, central and downwind sections) after which flies were released individually on the central tree and their movements observed for 15 min. The experiment was designed as a two‐way factorial with no odour and odour release rates of ca. 18 and ca. 500 μg h−1 and still air and wind speeds of 0.8 and 1.6 m s−1 as treatments. Both wind speed and odour had significant effects on flight frequency (landings min−1) and general fly activity. Fly movement decreased as wind speed increased from 0 m s−1 to 0.8 and 1.6 m s−1, but this decrease was attenuated when air carried apple volatiles. When air was odour‐free, flies exposed to 1.6 m s−1 wind moved downwind.
Effects of temporary host deprivation on the reproductive potential of Trichogramma brassicae
Authors: Fleury F. , Boulétreau M.
Published: April 2011

The effect of host deprivation on the reproductive potential and parasitization behaviour of Trichogramma brassicae Bezdenko (Hymenoptera: Trichogrammatidae) was investigated. Upon emergence, females were deprived of hosts for one to four days, and were subsequently provided with an unlimited number of hosts. Regardless of its duration, deprivation did not affect female longevity, overall rate of progeny emergence, or progeny sex‐ratio. As deprivation time increased, however, the total number of parasitized hosts decreased from an average of 81.2 when hosts were provided at emergence, to an average of 34.0 when the waiting time was 4 days. This reduction was mainly due to the reduction in the parasitizations following the first laying peak, which was not affected when deprivation lasted fewer than 4 days. Trichogramma females are able to store ripe eggs (about 35) for 3 days without damage, but resorption occurs after four days of deprivation. Our results suggest that imaginal vitellogenesis occurs in this proovigenic wasp but that it is affected by host deprivation. The behaviour of females, as measured by the average distance between all parasitized hosts, was also modified by host deprivation. When deprivation exceeded one day, parasitizations were more scattered over the host patch. Moreover, increased deprivation times also appeared to delay the initiation of parasitization by a few hours.

Host shortage is likely to occur in nature, reducing the efficiency of Trichogramma as a biocontrol agent. The individual history of females must be taken into account in any study of the reproductive strategies of parasitoid females.
Leaf osmotic potential decrease: a possible cause of mortality of greenhouse whitefly eggs
Authors: Castañé C. , Savé R.
Published: April 2011

Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae) white eggs were detached from the leaf and exposed to a range of osmotic concentrations (between − 0.4 and − 2.2 MPa) in controlled conditions. Eggs were able to hatch in the low and medium solute concentrations. In the higher concentrations, eclosion was delayed and significant mortality due to egg desiccation was observed.

These results indicate leaf osmotic potential is a plant characteristic that affects greenhouse whitefly survivorship. Therefore leaf osmotic potential should be considered when evaluating greenhouse whitefly resistance.
Voltinism and diapause in the spruce web‐spinning sawfly Cephalcia arvensis
Authors: Battisti A.
Published: April 2011

Cephalcia arvensis Panzer (Hym., Pamphiliidae) spends most of the life cycle as a prepupa inside an earth‐walled chamber in the soil of spruce (Picea abies Karst.) forests. There are two types of prepupae in diapause in the soil, the eonymph and the pronymph. Prolonged diapause as an eonymph occurs in prepupae just after soil penetration at temperatures below 12 °C. Eonymphs change into pronymphs during the following summer and the life cycle lasts for two years. Mature larvae that enter the soil at temperatures above 12 °C change immediately into pronymphs and these individuals will emerge during the next spring. Other factors such as photoperiod do not appear to be correlated with prolonged diapause. The depth reached by the mature larvae in the soil is proportional to their size and inversely proportional to the soil temperature. Consequently, voltinism depends on both the conditions affecting development of the larvae in the crowns and the temperature at different soil depths.
Host‐finding behavior, host acceptance, and host suitability of the parasite Xanthopimpla stemmator
Authors: Hailemichael Y. , Smith J. W. , Wiedenmann R. N.
Published: April 2011

Xanthopimpla stemmator (Thunberg)(Hymenoptera: Ichneumonidae), a solitary endoparasite of pupae of Old World lepidopteran stalkborers, was recently imported into Texas as a candidate for biological control of New World stalkborers. Information on host acceptability, host suitability and cues responsible for host finding were necessary to gain an insight into parasite/host interactions, because of the absence of a coevolutionary history. Xanthopimpla stemmator females were exposed to laboratory‐reared one‐to six‐day‐old Diatraea saccharalis (F.) pupae. An average of 62% of host pupae were accepted and all ages of pupae were equally acceptable. Host suitability decreased with host age. One‐to five‐day‐old host pupae averaged 31–37% suitability, whereas only 19% of 6‐day‐old pupae were suitable. Successful parasitization, defined as the product of the proportion accepted and the proportion suitable, decreased from 22–23% for 1‐, 2‐ and 3‐day‐old pupae to 13% for 6‐day‐old pupae. Sex ratio (female:male) of the parasite progeny increased with host age. Females comprised 47% of total parasite progeny of 1‐day‐old and 84% of 6‐day‐old pupae. The increase in percent females was a result of a similar number of females in all age classes, coupled with a decrease in the number of males from older hosts. Xanthopimpla stemmator superparasitized 61% of accepted D. saccharalis pupae in the laboratory. On dissection, 73% of host pupae with multiple probe wounds were found to contain parasite eggs or larvae; these hosts contained up to 10 eggs or 7 first‐instar larvae. Increased numbers of probes by the parasites were associated with an increase in successful parasitization. Host seeking activity in X. stemmator was stimulated by the presence of larval frass, host odor and movement of host pupae. Results suggest that X. stemmator is a good candidate for biological control of D. saccharalis and possibly other factitious stalkborer hosts.
Can pesticide formulations significantly influence pest behavior?: the case of Tetranychus urticae and dicofol
Authors: Edwards Mary H. , Kolmes Steven A. , Dennehy Timothy J.
Published: April 2011

Pesticide formulations profoundly influenced the encounter of pest with pesticide. In four differently formulated treatments of identical dicofol concentration, total time spent on treated areas of a checkerboard residue immediately following treatment varied dramatically from 13.3% on Modified Formulation residues to 42.1% on 50 Wettable Powder residues. With 24 h old checkerboard residues, total time spent on treated areas varied from a low of 30.1% with Modified Formulation residues to a high of 45.1% with Emulsifiable Concentrate residues. Different formulations exhibited dramatically different decay of repellency over a 24 h period. The greatest loss of repellency was found on Modified Formulation residues, although this formulation was still the most repellent at 24 h. Observations were made of three behavior patterns with both 0 h and 24 h old residues of four formulations of dicofol. Our results indicate that the constituents of some pesticide formulations may elicit behavior that greatly reduces pest encounter with pesticide. To study this phenomenon it is necessary to observe pest behavior with discontinuous residues.
Gall initiation success and fecundity of Dasineura marginemtorquens on variable Salix viminalis host plants
Authors: Glynn Carolyn , Larsson Stig
Published: April 2011

Genotypic and environmentally determined differences in Salix viminalis L. suitability for Dasineura marginemtorquens (Bremi) (Diptera: Cecidomyiidae) growth and survival were investigated in laboratory and field experiments. Earlier studies have documented high neonate larval mortality on certain S. viminalis genotypes. Here we present results from laboratory experiments which show no difference in larval establishment behaviour on resistant and susceptible willow genotypes. These data indicate that larvae are not able to detect the plant characteristic responsible for resistance. In a field study insect performance was measured on willow shoots of dissimilar size. Adult body size was positively correlated to willow shoot length. In turn, body size was positively correlated to potential fecundity. These results are discussed in relation to observed high densities of D. marginemtorquens in vigorously growing willows cultivated for biomass production.
Mate recognition in Cryptomyzus aphids: copulation and insemination
Authors: Guldemond J. Adriaan , Dixon Anthony F.G. , Tigges Wouter T.
Published: April 2011

The specificity of the mate recognition system in three species of the aphid genus Cryptomyzus (Homoptera: Aphididae: Aphidinea) that reproduce sexually on the same host plant, red currant, was studied. Mate recognition at the level of life cycle forms, sister species and more distantly related species was studied. A host race on black currant was used to determine the effect of the host plant on mate preference. The males do not have a specific courtship behaviour and matings readily occurred between different species. However, in choice tests the matings between the more distantly related species resulted only in intraspecific inseminations, and those between the sister species in a higher frequency of intraspecific, compared to interspecific, matings. In no‐choice experiments mating between the more distantly related species occurred but did not result in insemination, and in sister species in a reduced insemination success compared to intraspecific matings. Thus, there is specific mate recognition in aphids, which prevents or reduces interspecific insemination but not interspecific mating. In the host races, host plant choice determined mating and insemination, and the life cycle forms did not show any difference in mate recognition.
The effect of food deprivation on aeronautic dispersal behaviour (ballooning) in Erigone spp. spiders
Authors: Weyman G. S. , Sunderland K. D. , Fenlon J. S.
Published: April 2011

Adult male and female Erigone spp. (Araneae: Linyphiidae) spiders were kept without food for several days. Groups of spiders were tested for aeronautic dispersal behaviour (ballooning) in the laboratory. The validity of the assessment method was tested. In comparison with satiated spiders, the starved group exhibited an increased tendency to engage in aeronautic dispersal behaviour. A consistent trend for increased dispersal behaviour was detected in three independent experiments. Implications for spiders in agro‐ecosystems are discussed briefly.
The influence of queens of the ant Paratrechina flavipes on daughter and non‐daughter workers, for the suppression of sexual production
Authors: Ichinose Katsuya
Published: April 2011

The influence that the queen of Paratrechina flavipes (Smith) (Hymenoptera: Formicidae) has upon workers was investigated in field and laboratory nests. There was no significant difference in sexual production, either of gynes or males, between field queenright and queenless nests of the ant. A replicated laboratory experiment revealed that workers lay fewer eggs and rear fewer sexual larvae in the presence of their mother queen, while this reduction is not observed in workers with influence of non‐mother queens. The results seem to support the queen's signal hypothesis by Keller & Nonacs (1993). The contradiction is explained by workers rearing sexuals in queenless satellite nests. There exists a probably complex regulation of the transfer of larvae between satellite and mother nests.
Effect of environmental conditions on progeny production by the oriental cockroach Blatta orientalis
Authors: Le Patourel G.
Published: April 2011

Oothecal production by both mated and unmated female oriental cockroaches Blatta orientalis L. (Dictyoptera: Blattidae) was measured at temperatures between 10° and 28 °C. Production was inhibited at 15 °C and below, and only partially recovered when cooled insects were returned to 28 °C. Mean incubation times for oothecae varied from 41.4 to 43.9 days at 28 °C, 60.5 to 60.8 days at 24 °C and 86.8 to 91.7 days at 20 °C depending on RH. No nymphs emerged from oothecae kept continously at 15 °C, 75% RH over a 6 month period, although hatch at both 10° and 15 °C was observed in a few cases when oothecae containing eggs close to hatching (28–35 days from deposition, maintained at 28 °C) were transferred to these lower temperatures. The mean number of nymphs emerging from oothecae (non‐hatching oothecae included) increased with temperature over the range 20–28 °C and with RH over the range 43–95% RH. At 28 °C there was a decline in oothecal viability in the range 95–100% RH attributable to fungal attack, and few nymphs emerged from oothecae kept at 0% RH. The viability of oothecae subjected to periods of cold exposure and then returned to 28 °C decreased with decreasing exposure temperature (10° to −5 °C), increasing exposure period (2 h to 30 days) and stage of embryogenesis when exposed (oothecae incubated for 0 to 7 days at 28 °C prior to cold exposure less cold‐tolerant than oothecae incubated for 28 to 35 days).
Preselection of predatory mites to improve year‐round biological control of western flower thrips in greenhouse crops
Authors: van Houten Yvonne M. , van Rijn Paul C. J. , Tanigoshi Lynell K. , van Stratum Pam , Bruin Jan
Published: April 2011

In spring and summer, two groups of natural enemies are successfully used for biological control of western flower thrips, Frankliniella occidentalis (Pergande) in greenhouses: phytoseiid mites (Amblyseius cucumeris (Oudemans) and, to a lesser extent, A. barkeri (Hughes)) and anthocorid bugs (Orius spp.). During winter, however, these predators often fail to control the pest. One likely cause for failure is the predators' tendency to enter diapause under short day conditions. In addition, eggs of predatory mites are generally susceptible to low humidity conditions, which often arise in greenhouses when outside temperatures drop below zero, or at bright, hot days in summer. In search for a thrips predator that is not hampered by these conditions, five subtropical phytoseiid species were selected which were known to feed on thrips: A. hibisci (Chant), A. degenerans Berlese, A. limonicus s.s. Garman and McGregor, A. scutalis (Athias‐Henriot) and A. tularensis (Congdon). These species were compared to A. cucumeris and A. barkeri, with respect to the following features: (1) predation and oviposition rate with young F. occidentalis larvae as prey, (2) oviposition rate on a diet of sweet pepper pollen, (3) drought tolerance spectrum of eggs, and (4) incidence of reproductive diapause under short day conditions. The results showed that A. limonicus exhibited the highest predation and oviposition rates on a diet of thrips larvae. Moreover, A. limonicus females showed total absence of diapause under the conditions tested. A major disadvantage of this species was, however, that its eggs were most sensitive to low air humidity conditions. Least sensitive to low air humidity were eggs of A. degenerans and A. hibisci. Females of A. degenerans and A. hibisci also showed total absence of diapause, and intermediate rates of predation and oviposition, on both thrips larvae and pollen. In conclusion, we argue that A. degenerans and A. hibisci are the most promising candidates for biological control of F. occidentalis under conditions of low humidity and short day length. The success of these candidates remains to be shown in greenhouse experiments.
Visual and olfactory location of biotopes, prey patches, and individual prey by the ladybeetle Chilocorus nigritus
Authors: Hattingh Vaughan , Samways Michael J.
Published: April 2011

Foraging behaviour of the predator Chilocorus nigritus (Fabricius) (Coleoptera: Coccinellidae) at the three spatial levels of biotope, prey patch and individual prey, was studied in the laboratory, and related to behaviour in the field. Vertically oriented parallel lines were more attractive than the same shapes in a horizontal position. A simulated horizon with a tree line was preferred to a simulated flat horizon. They were attracted to a tree image for the first 2 h of exposure, but were less attracted after longer exposure, possibly due to habituation. Leaf shape was recognised, and simple ovate leaves were preferred to compound bipinnate leaves and to squares. These responses were associated with biotope selection for feeding and aggregation at aestivation sites. The location of prey patches by adults involved prey odour but the location of such sites by larvae did not. Adults detected individual prey visually and olfactorily over short distances but physical contact with prey was required for detection by larvae. Location of individual prey and prey patches by adults and larvae was facilitated by alternation between intensive and extensive search. The differences in the ability of larvae and adults to locate prey, stem from the adults being the active locators of biotope and patch, whereas the comparatively immobile larvae depend on their parents' ability for long‐range location of prey. Two hypotheses concerning coccinellid foraging behaviour are proposed. Firstly, the duration of response to a visual cue is related to the distance over which such a cue may be perceived. It follows that habituation to closer range cues occurs more rapidly than to longer range cues. Secondly, visual cues used by adults at the different spatial levels of prey location, and the location of mates and aggregation sites, have the same or similar shape. These results also provide guidelines for orchard management to maximise the biocontrol value of this species.
Photoperiodic induction of larval diapause and temperature‐dependent termination in a wild multivoltine bruchid, Kytorhinus sharpianus
Authors: Ishihara Michihiro , Shimada Masakazu
Published: April 2011

A wild bean weevil, Kytorhinus sharpianus Bridwell (Coleoptera: Bruchidae), has a multivoltine life cycle and enters a hibernal larval diapause at the fourth instar under a short daylength (Shimada & Ishihara, 1991). Here, we investigated their diapause incidence under different photoperiods at 24 °C and 27 °C. The critical photoperiods for diapause induction were 14.5 h at 24 °C and 14 h at 27 °C. The stages susceptible to diapause‐inducing stimuli were estimated by transferring larvae of various instars from long days to short days and vice versa. Then we investigated the incidence of larval diapause. The sensitive stage was estimated to be from the third to early fourth instar. Though larval diapause, which was induced under a short daylength, was terminated only by increasing the daylength, the termination was more synchronized by an exposure to a low temperature followed by increasing temperature, irrespective of photoperiod.
Synchronous growth of a parasitoid, Perilitus coccinellae, and teratocytes with the development of the host, Coccinella septempunctata
Authors: Kadono‐Okuda Keiko , Sakurai Hironori , Takeda Susumu , Okuda Takashi
Published: April 2011

The relationship between the development of Coccinella septempunctata brucki Mulsant (Coleoptera: Coccinellidae) and its parasitoid, Perilitus coccinellae (Schrank) (Hymenoptera: Braconidae) was studied at two photoperiods (L16:D8 and L12:D12) at 26 °C. The development of P. coccinellae is well synchronized with the physiological state of the host, C. septempunctata, which can be parasitized not only as adult but also as larva or pupa. The parasitoid larva completed larval development within 19 days in a non‐diapausing host, while in diapausing adults as well as in pupae held at diapause‐averting conditions, the parasitoid larva ceased growth at the first instar. Growth was resumed when diapause of the host terminated or by the emergence of the adult host from the pupa.

About 550 spheric cells, teratocytes, were liberated into the host hemocoel when the parasitoid egg hatched. The teratocytes increased in size in the active host, while their development was arrested in the diapausing host. Application of methoprene caused diapause termination of both host and parasitoid larva. The results indicate that the development of the larva of P. coccinellae depends on the physiological conditions of the host, C. septempunctata brucki. The host‐parasite relation thus represents an ‘endogenous synchronization’ in the sense of Schoonhoven's definition.
Surfactant‐enhanced essential oils as mosquito larvicides
Authors: Corbet Sarah A. , Danahar G. W. , King V. , Chalmers C. L. , Tiley C. F.
Published: April 2011

Using laboratory bioassays with fourth‐instar Culex pipiens form molestus larvae, we explored the larvicidal properties of two representative plant‐derived oils, eucalyptus oil and turpentine (two grades), and cineole, the main component of eucalyptus oil. Each was larvicidal alone, but efficacy was enhanced when the spreading pressure was increased by adding 1% insoluble surfactant (Arosurf MSF) plus 1% detergent. Cheap turpentine was more effective than more refined turpentine. These mixtures were compared with the familiar surface‐active larvicides Arosurf and Golden Bear Oil. At a dose of 2 μl per tub (=0.13 μl cm−2), enhanced by surfactants (turpentine:Arosurf:detergent 100:1:1 by volume), refined turpentine acted faster than Arosurf alone, causing higher mortality at 24 and 48 h after treatment but equivalent mortality at 72 h. It immobilised more larvae than Golden Bear Oil in the first three hours, but was less effective over 24 h. Crude turpentine enhanced by surfactants immobilised about as many larvae as Golden Bear Oil over 24 h. These findings indicate that plant essential oils merit further attention as widely available, environmentally benign mosquito larvicides.
Differential utilization of nutrients during development by the xylophagous leafhopper, Homalodisca coagulata
Authors: Brodbeck Brent V. , Andersen Peter C. , Mizell Russell F.
Published: April 2011

Utilization of nutrients at different stages of development was examined for the xylophage, Homalodisca coagulata (Say). Survivorship and consumption rates of second‐instar, fourth‐instar and adult leafhoppers were measured daily on the hosts Lagerstroemia indica L. and Euonymus japonica Thumb. Rates of consumption, assimilation efficiencies and daily assimilation of nitrogen, carbon, and individual organic compounds were calculated based on chemical analyses of xylem fluid and insect excreta. Gross growth efficiencies of diet utilization were also estimated by comparing biomass of young adults to estimates of nutrient utilization of the two host species.

Different instars survived and utilized nutrients at varying rates on the two hosts. Second‐instar leafhoppers survived at higher rates and utilized nitrogen more efficiently on E. japonica than on L. indica. However, assimilated nitrogen was much less as a result of lower consumption rates. In contrast, adults on L. indica had increased longevity, utilized carbon more efficiently, and assimilated higher quantities of both carbon and nitrogen than those on E. japonica. Efficiencies of nutrient utilization were high for H. coagulata compared to folivores or phloem feeders, particularly in the conversion of ingested nutrients to assimilated compounds. Variations in diet utilization during development are discussed in terms of polyphagy.
Toxicity of lectins and processing of ingested proteins in the pea aphid Acyrthosiphon pisum
Authors: Rahbé Yvan , Sauvion Nicolas , Febvay Gérard , Peumans Willy J. , Gatehouse Angharad M. R.
Published: April 2011

Acute toxicity of thirty lectins was tested against the pea aphid Acyrthosiphon pisum (Harris) (Homoptera, Aphididae: Macrosiphini). Activity was measured on artificial diets containing moderate concentrations of lectins (10–250 μg/ml) by scoring mortality and growth inhibition over the whole nymphal period (7 days at 20°C). Most of the proteins tested exhibited low toxicity, but some induced significant mortality; these included the lectins from jackbean (Concanavalin A), amaranth, lentil and snowdrop. There was no direct correlation between toxicity and sugar specificity of the lectin; however, many mannose‐binding lectins were toxic towards A. pisum. Concanavalin A was also tested on five other aphid species (Aphis gossypii, Aulacortum solani, Macrosiphum euphorbiae, Macrosiphum albifrons and Myzus persicae) at concentrations between 10–1500 μg/ml. Mortality was very variable from one species to another. Strong growth inhibition invariably occurred within this concentration range, although dose‐response curves differed substantially between aphid species. The peptidase complement of A. pisum's digestive tract was also investigated, as well as the oral toxicity of some protease inhibitors (PIs) to this aphid. Most protein PIs were inactive, and no part of the digestive tract contained detectable amounts of endo‐protease activity. This is in contrast to the strong amino‐peptidase activity which was shown to occur predominantly in the midgut and crop portions of the digestive tract. The potential of lectins in transgenic crops to confer Host‐Plant Resistance to aphids is discussed.
Cross habituation to feeding deterrents and acceptance of a marginal host plant by Pieris rapae larvae
Authors: Huang Xin Pei , Renwick J. A. A.
Published: April 2011

Sensitivity of the cabbage butterfly, Pieris rapae L. to feeding deterrents was compared for larvae reared on different food sources under laboratory conditions. Since cabbage‐reared larvae normally reject nasturtium, Tropaeolum majus L., the effects of previous exposure to allelochemicals on larval acceptance or rejection of this plant were also examined. When compared with cabbage‐reared larvae, nasturtium‐reared larvae were less sensitive to feeding deterrents including cymarin, erysimoside and 2‐O‐β‐D‐glucosyl cucurbitacin E. Nasturtium‐reared larvae were insensitive to chlorogenic acid, which was deterrent to cabbage‐reared larvae. Feeding by larvae reared on a wheat germ diet was not deterred by these compounds. The results indicate that dietary experience can extensively affect larval sensitivity to feeding deterrents and that cross habituation of larvae to deterrents occurs in response to certain chemical constituents of nasturtium and wheat germ diet. Digitoxin, however, proved to be an exception. Larvae reared on either nasturtium or wheat germ diet were as sensitive to digitoxin as those reared on cabbage. Previous results have shown that rejection of nasturtium by cabbage‐reared larvae is due to the presence of strong feeding deterrents in this plant. However, more than 50% of 2nd instar larvae reared from neonate on cabbage leaves treated with strophanthidin, cymarin, erysimoside, digitoxigenin and digitoxin accepted nasturtium as a food source. 2‐O‐β‐D‐glucosyl cucurbitacin E, 2‐O‐β‐D‐glucosyl cucurbitacin I and rutin were also active in causing larvae to feed on nasturtium. Thus dietary exposure to unrelated plant chemicals can profoundly affect insect acceptance of a plant that contains feeding deterrents.
Efficacy of Carpophilus aggregation pheromones on nine species in northeastern Ohio, and identification of the pheromone of C. brachypterus
Authors: Williams R. N. , Ellis M. S. , Bartelt R. J.
Published: April 2011

Aggregation pheromones for seven Carpophilus (Coleoptera: Nitidulidae) species were field tested at a site with a rich nitidulid fauna in Ohio, USA, during the summers of 1992 and 1993. The pheromones used were blends identified for: Carpophilus antiquus (Melsheimer), C. brachypterus (Say), C. freemani Dobson, C. hemipterus (L.), C. lugubris Murray, C. mutilatus Erichson, and C. obsoletus Erichson. Each pheromone was used in conjunction with whole wheat bread dough, an effective co‐attractant. The pheromone of C. brachypterus Say was identified during the course of this study and was also tested; males emitted a 100:6:11:4:3 blend of (2E, 4E, 6E, 8E)‐3, 5, 7‐trimethyl‐2, 4, 6, 8‐decatetraene, (2E, 4E, 6E, 8E)‐3, 5, 7‐trimethyl‐2, 4, 6, 8‐undecatetraene, (2E, 4E, 6E, 8E)‐7‐ethyl‐3, 5‐dimethyl‐2, 4, 6, 8‐decatetraene, (3E, 5E, 7E, 9E)‐4, 6, 8‐trimethyl‐3, 5, 7, 9‐undecatetraene and (2E, 4E, 6E, 8E)‐7‐ethyl‐3, 5‐dimethyl‐2, 4, 6, 8‐undecatetraene, respectively. All species responded favorably to their own pheromones with the exception of C. obsoletus, which was not present in this area. Strong mutual cross attraction was observed between C. brachypterus and C. hemipterus. In addition, C. lugubris responded to the pheromones of C. obsoletus and C. hemipterus and, more weakly, to those of C. freemani and C. brachypterus; C. freemani responded slightly to the pheromone of C. mutilatus; and C. antiquus responded to the pheromone of C. lugubris. In most cases, cross attraction was related to the species involved sharing pheromone components. For C. antiquus, however, the response to the C. lugubris pheromone was apparently kairomonal. C. corticinus, C. marginatus, C. marginellus, and C. sayi, for which pheromones are not known, were attracted to the pheromone of C. lugubris and in some cases to other pheromones. Significant numbers of Colopterus spp. responded to the blends for C. lugubris, C. hemipterus, C. brachypterus, and probably, C. obsoletus.
Toxicity of plumbagin and juglone to the eggs of the cotton stainer, Dysdercus koenigii
Authors: Rao R. V. Satyanarayana , Gujar G. T.
Published: April 2011

Toxicity of two plumbaginoids viz., plumbagin and juglone to the eggs of the cotton stainer, Dysdercus koenigii was studied by a residual film technique. Of these two, plumbagin showed the higher toxicity against different‐age eggs with LC50 ranging from 0.0044 to 0.0066%. Eggs showed low susceptibility in the middle of embryogenesis. The toxicity of plumbaginoids, especially plumbagin, is discussed in relation to mode of action and prospects of its use as an ovicide in control of the insect.
High oviposition rate of Dasineura marginemtorquens on Salix viminalis genotypes unsuitable for offspring survival
Authors: Larsson Stig , Glynn Carolyn , Höglund Solveig
Published: April 2011

A short history of contact between Dasineura marginemtorquens and resistant genotypes of Salix viminalis has previously been suggested as an explanation for a poor correspondence between female oviposition preference and larval performance on certain host types. The discovery of resistant wild willows instigated a quest for an alternative hypothesis. This study presents data from laboratory and field experiments that were designed to detect variability in host preferences of individual members of the midge population. Field tests showed that the oviposition site choices of females followed the same random‐natured pattern as choices of females in laboratory situations. Ovipositing females did not distinguish between willow genotypes with very high or very low larval mortality. No differences in post‐alighting behavior of midges on the two willow types were discovered. Observations revealed that females usually remained and oviposited on the first plant with which they came into contact, regardless of genotype.
Visual behaviour of neonate larvae of the light brown apple moth
Authors: Harris M. O. , Foster S. P. , Bittar T. , Ekanayake K. , Looij K. , Howard A.
Published: April 2011

When neonate larvae of a leafroller moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) were released into the middle of a circular arena with blue paper on one side of the arena and apple foliage on the other side, more larvae walked towards the apple foliage. These oriented responses were enhanced, in terms of the number of larvae responding, by increasing the amount of light reflected from or transmitted through apple foliage. Larvae also responded to painted targets, and specifically to targets reflecting light in the region of 470–570 nm (green‐yellow region to the human eye). When the amount of 470–570 nm reflected from targets was reduced, numbers of larvae responding to targets decreased. The addition of 400–500 nm reflected light to 470–570 nm reflected light also resulted in a reduction of oriented responses to targets. Tests using neutral colours (white, black, and a series of greys) indicated that, in the absence of targets reflecting primarily in the 470–570 nm region, larvae oriented towards targets with low levels of reflectance. When the orientation of walking larvae was measured at various distances from targets of different colours or diameters, targets subtending 5–8 degrees elicited responses from 50% of all larvae. Behaviour other than walking was also influenced by visual stimuli: fewer larvae spun down on a silken thread when blue paper was placed beneath a walking platform than when brown or green papers were present.
Hypertension in Diabetes: Treatment Considerations
Authors: Glandt Mariela , Bloomgarden Zachary T.
Published: April 2011

Treatment of blood pressure in the patient with diabetes remains a challenge. While data extrapolated from many trials seemed to imply that lower blood pressures leads to more favorable cardiovascular outcomes, this paper reviews newer trials designed to treat to blood pressure targets below 130/80 mmHg in patients with long term established diabetes, which showed that this goal may prove more harmful than helpful. In clinical practice this may be less relevant due to the fact that less than half of patients are even at the goal of 130/80. The interaction between glucose control and blood pressure control are also discussed, emphasizing the importance of multifactorial treatment. J Clin Hypertens (Greenwich). 2011;13:314–318. © 2011 Wiley Periodicals, Inc.
Hypertension and Lipid Management in Prediabetic States
Authors: Garber Alan J.
Published: April 2011

Patients with prediabetes have impaired fasting glucose, impaired glucose tolerance, and the metabolic syndrome. They have similar coronary heart disease risk rates as patients with type 2 diabetes. Goals and agents for blood pressure and lipid management should be the same for patients with prediabetes as those for patients with overt diabetes. Multiple antihypertensive agents are likely necessary for normotension. Aggressive statin usage is the first‐line lipid therapy and concomitant fibrate and nicotinic acid usage should be reserved for failures in primary prevention. J Clin Hypertens (Greenwich). 2011;13:270–274. © 2011 Wiley Periodicals, Inc.
Desperately Seeking Diarrhoea: Outbreak of Haemolytic Uraemic Syndrome Caused by Emerging Sorbitol‐Fermenting Shiga Toxin‐Producing Escherichia coli O157:H‐, Germany, 2009
Authors: Nielsen S. , Frank C. , Fruth A. , Spode A. , Prager R. , Graff A. , Plenge‐Bönig A. , Loos S. , Lütgehetmann M. , Kemper M. J. , Müller‐Wiefel D. E. , Werber D.
Published: April 2011

Infection with sorbitol‐fermenting Shiga toxin‐producing Escherichia coli O157:H‐ (sf STEC O157:H‐) is rare, but emerging in Europe. The pathogen is typically isolated from paediatric patients with life‐threatening haemolytic uraemic syndrome (HUS). It is unclear whether this observation primarily reflects the pathogen’s virulence or its complex laboratory diagnosis, not routinely conducted in diarrhoeal patients. In summer 2009, four boys living in the same suburb in Germany developed diarrhoea‐associated HUS: three were infected by sf STEC O157:H‐ and one died. We conducted two analytical epidemiological studies, an extensive search for diarrhoeal cases in potentially exposed groups, and an environmental investigation. Outbreak cases were residents of the suburb diagnosed with HUS, sf STEC O157:H‐ infection, or both between 24 July 2009 and 25 August 2009. Overall, we ascertained eight cases with a median age of 4 years (range: from 8 months to 9 years). Stool screening of 220 persons led to the identification of only four additional cases: two asymptomatic carriers and two diarrhoeal cases. HUS was strongly associated with visiting a local playground in July, particularly on 16th July (odds ratio = 42.7, P = 0.002). No other commonality, including food, was identified, and all environmental samples (n = 24) were negative. In this localized non‐foodborne outbreak, the place of likely infection was a local playground. Sf STEC O157:H‐ infection apparently limits itself rarely to diarrhoeal illness and progresses frequently to HUS. Therefore, detection of and response to this hypervirulent pathogen primarily relies on HUS surveillance.