Detection and characterisation of three novel species of reovirus (Reoviridae), isolated from geographically separate populations of the winter moth Operophtera brumata (Lepidoptera: Geometridae) on Orkney

Geographically separate populations of winter moth (Operophtera brumata L.) were sampled in heather habitats on the Orkney Isles in order to investigate the prevalence of virus pathogens. Reoviruses were isolated in 11 of the 13 winter moth populations sampled, with 3 novel species being detected. Two species of Cypoviridae (CPV) were isolated, Operophtera brumata CPV18 and O. brumata CPV19, with one host population suffering 46% infection prevalence of OpbuCPV19. A third virus, O. brumata Reovirus (OpbuRV), was isolated from both winter moth and a hymenopteran parasitoid wasp, Phobocampe tempestiva, which is abundant in these populations. This was identified as a non-occluded reovirus, which was clearly able to infect and persist in both the lepidopteran and the hymenopteran host. The genomes of the three viruses were characterised using gel electrophoresis and the virus structure was investigated using transmission electron microscopy. The relationship of these viruses with a baculovirus that also infects winter moth, OpbuNPV, was investigated, as well as the association of OpbuRV with P. tempestiva. The detection of such viruses is discussed with reference to studies of similar viruses in other lepidopteran and hymenopteran host systems.     

Host-mediated effects of feeding by winter moth on the survival of Euceraphis betulae

Abstract 1. A potential host-mediated interaction between the birch-feeding aphid Euceraphis betulae Koch (Homoptera: Aphididae) and Operophtera brumata L. (Geometridae: Lepidoptera) was investigated, by measuring survival and feeding preference responses of E. betulae to leaves damaged recently by O. brumata larvae.
2. Euceraphis betulae survival was considerably lower on damaged foliage than on undamaged foliage, both in field experiments using cages and on potted saplings in laboratory tests.
3. Euceraphis betulae did not avoid damaged foliage in field experiments although they did avoid damaged foliage in laboratory preference tests using individual leaves. A link between aphid preference and performance on damaged foliage could therefore be demonstrated in the greenhouse/laboratory but not in the field. Multiple factors may influence feeding preference in the more complex field environment.
4. These results suggest that host-mediated competition may occur between O. brumata and E. betulae , especially in outbreak years when winter moth populations are very high.     

THE TOXICITY OF CERTAIN SYNTHETIC ORGANIC COMPOUNDS TO THE FRUIT-TREE RED-SPIDER MITE

The acaricidal activity of ninety synthetic organic compounds has been investigated in the laboratory. Considerable differences were found between the winter eggs, the summer eggs and the adult female stages of the fruit-tree red-spider mite (Meta-tetranychus ulmi (Koch)) in their susceptibility to many of the compounds but two substances, namely azoxybenzene and n-dodecyl thiocyanate, were appreciably toxic to all three stages. Of the compounds showing promise against summer eggs and mites, bis-( p -chlorophenyl) methyl carbinol and 4-chloroazobenzene were the best, being highly toxic to both summer stages. Of the remainder, diphenylsulphone, 4-chlorodiphenylsulphone, azobenzene and hydrazobenzene were highly ovicidal, while C₁₂-C₁₃ alkyl thiocyanates and sec .-dodecyl thiocyanate gave high kills of the adult female mite.
Relationships between molecular structure and acaricidal activity have been sought. In a series of compounds characterized by the presence of two benzene nuclei connected by certain bridging groups, it has been found that activity to the summer stages of the mite can be influenced by alterations to the bridging group and by substitution in the benzene nuclei. Maximum activity appears to be associated with chlorine substitution in the para position in one nucleus and also with compounds of this type having unsubstituted nuclei.     

Differential susceptibility to variable plant phenology and its role in competition between two insect herbivores on oak

Abstract. 1. The population dynamics of Tortix viridana L. (Lepidoptera: Tortricidae) and Operophtera brumata L. (Lepidoptera: Geometridae) on the pedunculate oak Quercus robur L. are driven by the degree to which larval hatch coincides with oak budburst in spring.
2. Experiments with first instar larvae demonstrate that T. viridana has a much narrower dietary breadth, is less inclined to disperse from closed oak buds, and can resist starvation for longer periods than the polyphagous O.brumata.
3. As a result of its specialist foraging strategy, T. viridana may be less susceptible to mortality associated with colonization of oak in spring than O.brumata. This may explain why T. viridana populations are, on average, higher.
4. These results are discussed in the light of previous work which described the competitive advantage of O. brumata in field cage experiments. Stochastic mortality factors, which drive population change in both species independently of competition, favour T.viridana larvae, and over-ride the competitive superiority of O.brumata.     

Waves and synchrony in Epirrita autumnata/Operophtera brumata outbreaks. I. Lagged synchrony: regionally, locally and among species

1. In 1990-2003, during a complete 10-year outbreak cycle, the synchrony of the birch defoliating outbreaks of the geometrids Epirrita autumnata and Operophtera brumata was studied quantitatively in the northern part of the Fennoscandian mountain chain (the Scandes). Data were supplemented with similar data from 1964 to 1966 and historical information. A 30-year series of field data from one locality in southern Scandes made possible interregional comparisons. 2. In 1991, outbreaks started in north-eastern Fennoscandia and moved westward like a wave and reached the outer coast of north-western Norway in about 2000. This wave is a new observation. In the same years, a previously documented outbreak wave moved southward along the Scandes. 3. Outbreak periods have usually occurred around the middle of each decade. Seemingly unrelated population peaks at the decadal shift 2000 were reported from islands at the coast of north-western Norway. They are shown here to have been the final ripples of the east-west wave. 4. At some localities, O. brumata peaked 2 years after E. autumnata. A lag of 1 or 2 years also occurred at the locality in southern Scandes. This interspecific time lag is a new observation. In accordance with the north-south wave, a time-lag of 1-2 years occurred between the fluctuations of northern and southern E. autumnata and O. brumata populations. 5. The population peak of E. autumnata occurred 1 year earlier at one locality than at a nearby locality. This pattern and particular altitudinal shifts of the O. brumata population density at these localities repeated in two outbreak periods. This indicates that, for example, local climate may modify outbreak synchrony between nearby localities. 6. At the same localities, O. brumata peaked first at one altitude and 1 or 2 years later at another altitude. This vertical lag is a new observation. 7. E. autumnata shows fluctuation traits similar to some other cyclic animals, e.g. the larch budmoth in the European Alps, some European tetraonid birds and the Canadian snow-shoe hare. These similarities (and dissimilarities) in intra- and interspecific synchronies and causes of E. autumnata and O. brumata synchronies, regionally, locally and among the two species are discussed.     

Genetically variable nucleopolyhedroviruses isolated from spatially separate populations of the winter moth Operophtera brumata (Lepidoptera: Geometridae) in Orkney

Here we report a lepidopteran system in which a pathogen is both abundant and genotypically variable. Geographically separate populations of winter moth (Operophtera brumata L.) were sampled in heather habitats on the Orkney Isles to investigate the prevalence of a pathogen, O. brumata Nucleopolyhedrovirus (OpbuNPV), within the natural system. Virus was recorded in 11 of the 13 winter moth populations sampled, with two populations suffering mortality due to virus at levels of 50%. The virus genome from 200 single insect isolations was investigated for variation using restriction endonuclease digests. Twenty-six variants of OpbuNPV were detected using SalI. The polyhedrin gene of the virus was partially sequenced, allowing the relationship between the 26 variants to be portrayed as a cladogram. The phylogenetic relationship between OpbuNPV and other known baculovirus polyhedrin gene sequences was also established. The discovery of virus at such high prevalence is discussed with reference to occurrence and genetic variation of pathogens in other lepidopteran host populations. This study shows encouraging results for further studies into the role of pathogens in the regulation of host insect populations.     

Climate change and outbreaks of the geometrids Operophtera brumata and Epirrita autumnata in subarctic birch forest: evidence of a recent outbreak range expansion

1. Range expansions mediated by recent climate warming have been documented for many insect species, including some important forest pests. However, whether climate change also influences the eruptive dynamics of forest pest insects, and hence the ecological and economical consequences of outbreaks, is largely unresolved. 2. Using historical outbreak records covering more than a century, we document recent outbreak range expansions of two species of cyclic geometrid moth, Operophtera brumata Bkh. (winter moth) and Epirrita autumnata L. (autumnal moth), in subarctic birch forest of northern Fennoscandia. The two species differ with respect to cold tolerance, and show strikingly different patterns in their recent outbreak range expansion. 3. We show that, during the past 15-20 years, the less cold-tolerant species O. brumata has experienced a pronounced north-eastern expansion into areas previously dominated by E. autumnata outbreaks. Epirrita autumnata, on the other hand, has expanded the region in which it exhibits regular outbreaks into the coldest, most continental areas. Our findings support the suggestion that recent climate warming in the region is the most parsimonious explanation for the observed patterns. 4. The presence of O. brumata outbreaks in regions previously affected solely by E. autumnata outbreaks is likely to increase the effective duration of local outbreaks, and hence have profound implications for the subarctic birch forest ecosystem.     

Improved insect performance from host-plant defoliation: winter moth on oak and apple

ABSTRACT. 1. We test the hypothesis that defoliation has short-term and long-term negative effects on performance of winter moth Operophtera brumata L. on two species of food plants: Garry oak ( Quercus garryana Dougl.) and apple ( Malus domesticus L.).
2. Pupal weight (and hence potential fecundity of females) decreased with increased defoliation in the current year on both tree species.
3. Pupal weight increased, however, with increased level of defoliation in the previous year.
4. Increased weight of pupae from larvae which had fed on previously defoliated trees may buffer population decline by increasing fecundity of moths in the next generation.     

Maintenance of the phenology of the winter moth (Lepidoptera: Geometridae)

Adult winter moths ( Operophtera brumata (L.)) are active in late autumn or early winter. The eggs overwinter in the canopy of trees and hatch simultaneously with the bursting of host tree buds. Many young larvae disperse on the wind on silk strands. Larvae are polyphagus and feed until late spring when they pupate in soil or leaf litter. The duration of the egg and pupal stages is genetically determined and varies with latitude. The egg stage is long in the north and short in the south, while the pupal stage is short in the north and long in the south.
The literature on the ecology and physiology of winter moth is reviewed. The factors maintaining the unusual phenology are discussed. It is concluded that the larval stage is early because mature leaves of many host trees are unsuitable as food, because parasitism against later larvae is more intense, and because summer temperatures may be injurious to larvae. The adult period is late in the year so that the final stages of pupal development occur in cool conditions and so that adults emerge after most insect predators have ceased activity. Throughout most of the range retarding the adult emergence period would cause activity to be impeded by severe winter weather; in the south this is not so and it is suggested that eggs must be on the trees for a minimum period to ensure synchronization of egg hatch with bud burst. The protracted adult emergence period may be an adaptation reducing predation by birds.     

Phenological variation as protection against defoliating insects: the case of<Emphasis Type="Italic"> Quercus robur</Emphasis> and<Emphasis Type="Italic"> Operophtera brumata</Emphasis>

Phenological synchrony between budburst and emergence of larvae is critical for the fitness of many spring-feeding insect herbivores. Therefore, large intraspecific variation in timing of budburst of the host may have a negative effect on the herbivore. We studied how asynchrony between emergence of larvae and budburst affects the fitness of Operophtera brumata (Lepidoptera: Geometridae), a major defoliator of Quercus robur, which can adapt to the phenology of a single tree. It is known that, in maturing leaves of Q. robur, accumulation of condensed tannins has a negative effect on growth of O. brumata. However, there is no information about the effect of hydrolysable tannins and other phenolics that are potential antifeedants. In this study, we also analysed changes in secondary chemistry of the foliage of Q. robur and how different compounds are correlated with growth and survival of O. brumata. The effect of asynchrony on O. brumata was studied in rearing experiments. The neonate larvae were incubated without food for different periods of time. The decline in nutritional quality of foliage was estimated by rearing cohorts of larvae with manipulated hatching times on the leaves of ten individual Q. robur trees. For the chemical analysis, the foliage of these trees was sampled at regular intervals. In the absence of foliage, mortality of neonate larvae started to increase exponentially soon after the larvae emerged. If the larvae missed budburst, the decline in nutritional quality of the foliage led to increased mortality and lower body mass (= fecundity). Hydrolysable tannins were not significantly correlated with performance of the larvae. Only condensed tannins were found to correlate negatively with the growth and survival of O. brumata. Certain individual trees were unsuitable hosts for O. brumata because the decline in quality of the foliage was very rapid. Based on regression equations for increasing rate of mortality and decreasing fecundity, we calculated that a relatively small mismatch of +/-30 degree days between budburst and hatching of larvae leads to a 50% decrease in the fitness of O. brumata. Thus, large phenological variation within a Q. robur stand can limit the colonisation of neighbouring trees by dispersing larvae. Furthermore, the hybridisation of moths adapted to phenologically different trees may lead to maladapted phenology of their offspring.     

Aphis pomi (Hemiptera: Aphididae) population development, shoot characteristics, and antibiosis resistance in different apple genotypes

In high-value crops such as apple, Malus X domestica (Borkh.), insecticidal pest control is of high relevance. The use of resistant apple cultivars can increase the sustainability of pest management in apple orchards. Besides variation in plant chemistry that may influence plant resistance by antibiosis or antixenosis, plant growth characteristics also can affect plant susceptibility to pests such as aphids. Variable susceptibility to the apple aphid, Aphis pomi De Geer (Hemiptera: Aphididae), has been described for different apple cultivars. These observations were based on phenotypic surveys and no information on genetically based apple resistance to A. pomi is yet available. The objective of this study was to relate shoot growth characteristics with aphid population development, and to assess the genetic background of apple antibiosis-based resistance to A. pomi by quantitative trait loci (QTL) analysis. Aphid population development was repeatedly studied in the field in sleeve cages attached to 200 apple trees of different genotypes. Aphid population development was positively correlated to shoot length and growth, and it also was affected by climatic conditions. Indications for antibiosis-based resistance to A. pomi remained weak in the studied apple genotypes, and the only detected putative QTL on linkage group 11 of'Fiesta' apples was not stable for the different replications of the experiment. This lack of quantifiable resistance may be partly explained by environmental conditions related to aphid development in sleeve cages.     

Susceptibilities of apple aphid and spirea aphid collected from apple in the Pacific Northwest to selected insecticides

Laboratory bioassays using leaf disks of apple dipped in test solutions of insecticides demonstrated that the apple aphid, Aphis pomi De Geer, and the spirea aphid, Aphis spiraecola Patch, differed significantly in susceptibility to a number of insecticides registered for control of aphids on apple (Malus spp.). Compared with A. pomi, A. spiraecola was approximately four- and three-fold less susceptible to pirimicarb and lambda-cyhalothrin, respectively, whereas there was little difference in response to dimethoate. Pymetrozine is thought to act on aphids primarily as a feeding inhibitor. Exposure of aphids to this material generated data that fit the probit model for only half the tested clones. However, the LC50 value for one clone of A. spiraecola was nearly 1,000 times higher than the value for one clone of A. pomi. Although the results from these trials did not indicate that either species had developed significant levels of resistance to the test materials, differences in LC50 levels of > 10-fold suggest insecticide tolerances and the possibility of control failures in the future. The demonstrated differences in susceptibility to insecticides between these two morphologically similar species also should be considered during the evaluation of new products for use on apple.     

胡瓜钝绥螨对苹果全爪螨的生物防治效果

以生命表参数及天敌在室内和田间的应用效果来评价胡瓜钝绥螨对苹果全爪螨的控制效果.结果表明:胡瓜钝绥螨取食苹果全爪螨,能够完成发育历期并产卵,在(25±1)℃条件下一个世代仅需9.54d;其雌螨产卵期(24.85d)和寿命(38.52d)都比猎物的产卵期(15.93d)和寿命(34.79d)长,雌螨的平均产卵量仅为苹果全爪螨的56.1%;苹果全爪螨净增殖率(R0)和内禀增长率(rm)分别比胡瓜钝绥螨高103.9%和13.2%.室内释放情况下,无论益害比是1:30还是1:150,释放20d后防治效果均可达95%以上;在苹果示范园释放胡瓜钝绥螨,60d后防治效果达91.73%,比化防园高23.77%.表明胡瓜钝绥螨具有优良天敌的重要特征,在每叶苹果全爪螨低于2头时,果园释放胡瓜钝绥螨能有效控制苹果全爪螨的种群增长.     

Late autumn eclosion in the winter moth Operophtera brumata: compromise of selective forces in life-cycle timing

Abstract. 1. In eclosion experiments at constant temperatures (6, 9, 12, 15, 18, 21, and 25 °C), Operophtera brumata (L.) pupae were found to respond nonlinearly to temperature, with 9 °C giving the highest developmental rate.
2. Pupal development rate decreased and mortality increased at the highest and lowest temperatures. No pupae eclosed at 6, 21, or 25 °C.
3. Exposing pupae to periods of cold did not enhance their rate of development consistently, indicating that no pupal diapause occurred. Light did not affect the length of the pupal period significantly.
4. Variation in mean developmental rates across temperatures was modelled both for data in the present study (northern Norway) and for a previously published German study (20° further south). The German population had a longer pupal period at all temperatures than the northern population (mean difference of 88 days). The difference is assumed to be genetically based, and hence an adaption to (and not a consequence of) differences in phenology between the two sites.
5. The diversity of the life cycle of O. brumata is discussed. Timing of eclosion can be explained by the selective forces of predation by birds on the one hand and mortality due to early snowfall on the other.     

Evaluation of pheromone-baited traps for winter moth and Bruce spanworm (Lepidoptera: Geometridae)

We tested different pheromone-baited traps for surveying winter moth, Operophtera brumata (L.) (Lepidoptera: Geometridae), populations in eastern North America. We compared male catch at Pherocon 1C sticky traps with various large capacity traps and showed that Universal Moth traps with white bottoms caught more winter moths than any other trap type. We ran the experiment on Cape Cod, MA, where we caught only winter moth, and in western Massachusetts, where we caught only Bruce spanworm, Operophtera bruceata (Hulst) (Lepidoptera: Geometridae), a congener of winter moth native to North America that uses the same pheromone compound [(Z,Z,Z)-1,3,6,9-nonadecatetraene] and is difficult to distinguish from adult male winter moths. With Bruce spanworm, the Pherocon 1C sticky traps caught by far the most moths. We tested an isomer of the pheromone [(E,Z,Z)-1,3,6,9-nonadecatetraene] that previous work had suggested would inhibit captures of Bruce spanworm but not winter moths. We found that the different doses and placements of the isomer suppressed captures of both species to a similar degree. We are thus doubtful that we can use the isomer to trap winter moths without also catching Bruce spanworm. Pheromone-baited survey traps will catch both species.     

Host shifting by Operophtera brumata into novel environments leads to population differentiation in life-history traits

Abstract.  1. Operophtera brumata L. (Lepidoptera: Geometridae), a polyphagous herbivore usually associated with deciduous trees such as oak Quercus robur L . , has expanded its host range to include the evergreen species heather Calluna vulgaris (L.) Hull and, most recently, Sitka spruce Picea sitchensis (Bong.) Carrière.
2. Phenology, morphology, and survival of O. brumata were measured at several life-history stages in populations from the three different host plant communities sampled from a range of geographical locations. The data were used to test for population differences, reflecting the marked differences in host-plant secondary chemistry, growth form, and site factors such as climate. The hypothesis that spruce-feeding populations originated from populations feeding on moorland, commonly sites of coniferous afforestation, was also tested.
3. Altitude, not host plant species, was the major influence on the timing of adult emergence. An effect of insect population independent of altitude was found, implying that additional unidentified factors contribute to this phenological variation. Larval survival and adult size varied between populations reared on different host plant species. Survival of larvae was affected negatively when reared on the novel host plant, Sitka spruce, versus the natal plant (oak or heather) but oak and heather-sourced insects did not differ in survivorship on Sitka spruce.
4. Host range extension into novel environments has resulted in population differentiation to the local climate, demonstrating that host shifts pose challenges to the herbivore population greater than those offered by the host plant alone. The hypothesis that Sitka spruce feeding populations have arisen predominantly from moorland feeding populations was not supported.     

苹果全爪螨在吉尔吉斯与金冠苹果上的实验种群两性生命表

为明确新疆野苹果Malus sieversii吉尔吉斯与栽培苹果Malus domestica金冠对苹果全爪螨Panonychus ulmi生长发育和繁殖的影响, 在室温23±1℃, 相对湿度75%±5%, 光周期16L∶8D条件下, 组建了苹果全爪螨在吉尔吉斯和金冠上的实验种群两性生命表。结果显示： 吉尔吉斯和金冠对苹果全爪螨雌螨寿命、 产卵期及总产卵量等有明显影响、 而对总发育历期、 总产卵前期、 未成熟螨存活率等影响不显著。苹果全爪螨总发育历期在吉尔吉斯（雌12.60 d, 雄11.40 d）和金冠（雌12.54 d, 雄 11.67 d）上无显著差异, 雌成螨寿命在金冠(13.46 d)上显著长于在吉尔吉斯（10.88 d）上(P<0.05)。产卵期在金冠和吉尔吉斯上分别为10.55 d和8.30 d, 达到显著差异水平(P<0.05)。总产卵量在金冠上为34.12粒/雌, 显著高于在吉尔吉斯上（22.48粒/雌）(P<0.05)。苹果全爪螨在吉尔吉斯上内禀增长率(r)、 净增殖率(R₀)、 世代平均周期(T)、 周限增长率(λ)分别为0.1354, 11.96, 18.33和1.1450, 而在金冠上分别为0.1489, 17.39, 19.18和1.1606。由种群动态参数可知, 苹果全爪螨在金冠上种群数量增长快于在吉尔吉斯上。研究结果有助于深入了解该螨在新疆野苹果与栽培苹果上种群动态, 并为苹果抗螨性育种及害螨综合治理提供理论依据。     

Occurrence of Erwinia amylovora on Insects in a Fire Blight Orchard

In order to screen for natural dissemination of fire blight under field conditions, insects were caught in an experimental orchard and assayed on semi-selective agar plates and by BIO-polymerase chain reaction for their contamination with Erwinia amylovora , the causative agent of the bacterial disease. The pathogen was detected on 15 out of 348 insects collected (4.3%). The insects contaminated with E. amylovora have different living habits and belong to four different orders (Homoptera, Coleoptera, Hymenoptera and Diptera) and at least eight insect families (Aphididae, Psyllidae, Coccinellidae, Curculionidae, Ichneumonidae, Formicidae, Apidae, and Muscidae) and to other Brachycera. After contact of insects with E. amylovora , the pathogen could survive at least 5 days in/on the green lacewing ( Chrysoperla carnea ) and 12 days on aphids ( Aphis pomi ).     

Phenological diversity in the interactions between winter moth (Operophtera brumata) larvae and parasitoid wasps in sub-arctic mountain birch forest

Population cycles of the winter moth (Operophtera brumata) in sub-arctic coastal birch forests show high spatiotemporal variation in amplitude. Peak larval densities range from levels causing little foliage damage to outbreaks causing spatially extensive defoliation. Moreover, outbreaks typically occur at or near the altitudinal treeline. It has been hypothesized that spatiotemporal variation in O. brumata cycle amplitude results from climate-induced variation in the degree of phenological matching between trophic levels, possibly between moth larvae and parasitoids. The likelihood of mismatching phenologies between larvae and parasitoids is expected to depend on how specialized parasitoids are, both as individual species and as a guild, to attacking specific larval developmental stages (i.e. instars). To investigate the larval instar-specificity of parasitoids, we studied the timing of parasitoid attacks relative to larval phenology. We employed an observational study design, with sequential sampling over the larval period, along an altitudinal gradient harbouring a pronounced treeline outbreak of O. brumata. Within the larval parasitoid guild, containing seven species groups, the timing of attack by different groups followed a successional sequence throughout the moth's larval period and each group attacked 1-2 instars. Such phenological diversity within parasitoid guilds may lower the likelihood of climate-induced trophic mismatches between victim populations and many/all of their enemies. Parasitism rates declined with increasing altitude for most parasitoid groups and for the parasitoid guild as a whole. However, the observed spatiotemporal parasitism patterns provided no clear evidence for or against altitudinal mismatch between larval and parasitoid phenology.     

The role of honeydew as an ovipositional stimulant for two species of syrphids

The influence of honeydew contamination on egg laying by the syrphidsEpisyrphus balteatus (Deg.) andPlatycheirus albimanus (F.) on ears of wheat was investigated in a large laboratory flight cage. Artificially-applied honeydew elicited oviposition byE. balteatus but not byPlatycheirus albimanus.Episyrphus balteatus females landed more frequently on ears contaminated with honeydew than on clean ears, suggesting a response to honeydew volatiles. Honeydew from the rose-grain aphidMetopolophium dirhodum and from the pea aphidAcyrthosiphon pisum stimulatedE. balteatus to lay eggs, whereas honeydew from the nettle aphidMicrolophium carnosum did not. The number of eggs laid byE. balteatus increased with increasing honeydew concentration. At low honeydew concentrations the presence of aphids increased oviposition byE. balteatus, but aphid presence had little effect on the number of eggs laid at high honeydew concentrations.