Crucial factors determining the spatio-temporal distribution patterns of threeAthalia sawflies feeding on common cruciferous plants

Three Athalia sawflies, A. japonica, A. rosae and A. infumata, feeding on cruciferous plants, coexist in Japan. However, it is not known what ecological strategies they use and what environmental factors are crucial to such strategies. I attempted to explain these questions by examining the relationship between the spatio-temporal distribution patterns of three Athalia sawflies and their habitats in three districts (Lowland, Intermediate and Mountain). The three sawflies have different spatio-temporal distribution patterns, though they usually used common cruciferous plants. A. japonica was abundant in spring and autumn but disappeared during summer in all the districts. In the Lowland, populations of A. rosae and A. infumata, like that of A. japonica, crashed in summer. However A. rosae occurred mainly in summer in the Intermediate and Mountain. Although A. infumata occurred in the same seasons as A. rosae in all districts, population levels of A. infumata were always lower than those of A. rosae. The crucial factors controlling their population patterns were the availability of host plants and temperature. Population crashes of A. rosae and A. infumata were due to food depletion, and those of A. japonica were due to heat stress. On the other hand, their population patterns may be interpreted as phenological synchronization with their original host plants, though they all existed on common cruciferous plants. The three sawflies may have evolved different strategies to escape from unfavorable habitat conditions. Such strategies are speculated to be summer diapause in A. japonica, long distance migration in A. rosae, and local dispersal in A. infumata.     

Why does only Athalia Japonica enter summer diapause among three sympatric Athalia sawflies feeding on crucifers?

This report assesses the primary factor for the evolution of summer diapause of the three species of sawfly, Athalia japonica, A. rosae and A. infumata that feed on cruciferous plants and coexist in the same area. A. japonica has two discrete spring and autumn generations, but A. rosae and A. infumata 5–6 generations. Only A. japonica enters summer diapause in response to the long daylengths in spring. Although these three sawflies usually feed on the same cultivated crucifers, they differ markedly in the utilization of wild crucifers. They oviposit only on young leaves. A. japonica mainly uses Cardamine plants which sprout in spring and autumn. A. rosae and A. infumata primarily use hosts with new leaves all the year round, i.e. cultivated crucifers and Rorippa indica, respectively. The thermal threshold for development is lower in A. japonica than in the other two species. The low heat tolerance of A. japonica is adapted only to cool shady habitats where Cardamine grows. Presumably, summer diapause of A. japonica is adaptation to the deterioration of the primary host plants rather than unfavorable climatic conditions. This interpretation is supported by the movement patterns of the three Athalia sawflies, alternative means to escape from deteriorated habitat conditions.     

Population abundance and movement of Frankliniella species and Orius insidiosus in field pepper

1 A recent study revealed the capacity of the Orius insidiosus to suppress populations of Frankliniella spp. in field pepper during the spring when thrips are rapidly colonizing and reproducing. In this study, population abundance in pepper during spring, summer, and autumn was determined to understand better predator/prey dynamics under local conditions. Local movement between pepper flowers also was quantified to examine how population attributes of the predator allow suppression of rapidly moving populations of prey. 2 Randomized complete block experiments established in the autumn of 1998 and the spring of 1999 included treatments of biological and synthetic insecticides, which altered the population densities of predator and prey. Numbers of O. insidiosus in relation to prey were sufficient in 1998 to prevent build‐up of thrips populations. In 1999, populations of thrips were unable to recover from near extinction owing to persistence of the predator. The predator rapidly recolonized plots treated with insecticide. 3 Greenhouse plants of the same age as field plants were used to monitor movement by predators and prey. Movement by F. occidentalis was limited, whereas F. tritici and F. bispinosa moved rapidly to the greenhouse plants. The males of each thrips species moved more rapidly than the females. There was evidence that rapid movement assisted F. tritici and F. bispinosa in avoiding predation, but O. insidiosus also moved very rapidly to the greenhouse plants. This attribute explains the predator's ability to suppress thrips rapidly even when populations are rapidly colonizing and reproducing in the flowers.     

Differences in host plant selection among three Athalia sawflies feeding on crucifers in Japan

Abstract 1. The ways of using host plants were compared among the three Athalia sawflies [ A. japonica (Klug), A. rosae ruficornis Jakovlev, and A. infumata (Marlatt)] feeding on crucifers in Japan to determine whether host specialisation can explain the difference in their life-history traits. The occurrence of their larvae was examined on each crucifer species in the field, and the suitability of each crucifer species for the three successive steps of host use by the sawflies was evaluated: microhabitat selection by adult females, female oviposition, and larval growth.
2. There were 11 species of crucifer in the study area, and A. japonica , A. rosae , and A. infumata used nine, seven, and eight species respectively. Thus, sawfly host ranges overlapped.
3. Adult females of A. japonica , A. rosae , and A. infumata preferred shady clumps of crucifers, sunny clumps of crucifers, and disturbed areas respectively.
4. Unsuitable hosts for larval performance such as Brassica oleracea and Arabis plants were eliminated from the host ranges of the three sawflies.
5. Once they chose microhabitats, the suitability of each host plant for female oviposition and larval growth was similar.
6. Because of the divergent preferences for microhabitats, the host plants that were suitable for all the three steps were restricted to different sets of plants among the sawflies: Cardamine for A. japonica , cultivated crucifers ( Raphanus and Brassica ) for A. rosae , and Rorippa for A. infumata . These plants could be recognised as the respective primary host plants.
7. The spatio-temporal distributions of primary hosts were consistent with and explained the pattern of diapause and migration of each sawfly, suggesting that host specialisation caused their life-history traits to differentiate.     

Dependence of Asian honeybee on deciduous woody plants for pollen resource during spring to mid‐summer in northern Japan

Apis cerana japonica Radoszkowski, endemic to Japan, is known to be one of the most important pollinators for wild plants and crops, such as buckwheat, in cool to warm temperate Japan. To determine the degree of dependence of A. cerana japonica on forest resources, we analyzed pollen brought back to nests in a typical “Satoyama” landscape with relatively high deciduous forest coverage in northern Japan. We divided the landscape elements of the study area into three types: deciduous forest, conifer plantation and open land according to landcover digital data, and each pollen taxon was assigned to one of these three types of landscape elements. We collected total pollen loads of 15.75 g (total of colonies A and B) in May (spring), 1.57 g (total of colonies A and C) in June (early summer), 19.03 g (total of colonies A, B and C) in July (mid‐summer) and 45.61 g (total of colonies A, B and D) in September (autumn). Deciduous forests are the most important foraging habitats for A. cerana japonica in the “Satoyama” landscape especially from spring to mid‐summer when mass flowering of tall trees and shrubs species provides rich floral resources for developing bee colonies. On the other hand, the bees frequently foraged from herbaceous plant species in autumn when flowering of tree species reduces and herbaceous plant species have flowering peaks. In turn, the bees provide pollination services to a number of wild flowers blooming in various forest layers ranging from the canopy to the understory layer.     

Population dynamics of the cattle tick Rhipicephalus (Boophilus) microplus in a subtropical subhumid region of Argentina for use in the design of control strategies

The population dynamics of Rhipicephalus microplus (Ixodida: Ixodidae) in northwest Argentina was analysed to support the design of strategic methods for its control. Both parasitic and non‐parasitic phases were studied. The seasonal activity of R. microplus in its parasitic phase was characterized by three peaks in abundance: the first in mid–late spring; the second in summer, and the third in autumn. The non‐parasitic phase of R. microplus was characterized by a long total non‐parasitic period observed after exposures of females from mid‐summer to early autumn, a short total non‐parasitic period observed after exposures of females from late winter to late spring, a short period of larval longevity in early and mid‐summer, and no hatch of the eggs produced by females exposed in mid‐ and late autumn and winter. Treatments of cattle administered during the period from late winter to late spring will act on small cohorts of R. microplus, preventing the emergence of larger generations in summer and autumn. A 17‐week spelling period starting in late spring and early summer will be necessary to achieve optimal control of R. microplus free‐living larvae. If spelling begins in mid‐ or late summer or in autumn, the required period will be 26–27 weeks.     

Breeding biology of Tenagomysis tasmaniae Fenton,Anisomysis mixta australis (Zimmer) and Paramesopodopsis rufa Fenton from south-eastern Tasmania (Crustacea: Mysidacea)

The number, size and developmental stage of young in the brood pouch of female Tenagomysis tasmaniae, Anisomysis mixta australis and Paramesopodopsis rufa was recorded throughout the year. Breeding was intensive from spring till the end of autumn for the three species. Calculation of the egg ratio for each species showed that their major reproductive peaks occurred during spring and summer. A winter depression in the breeding cycle was observed for T. tasmaniae and P. rufa, but A. mixta australis ceased breeding during winter. Seasonal variation in the length of gravid females and number of young carried was evident for these three species. Females were longer in spring and summer and carried more young than in autumn and winter. A linear relationship between female length and brood size was demonstrated for each species; annual and seasonal equations were calculated for females carrying each developmental stage. The seasonal equations showed that for a female of given length fecundity was greater during spring than any other season. Natality was estimated to be highest during late spring, summer and early autumn for the three species. No seasonal variation in the size of eggs was evident for the three species. The reproduction pattern of T. tasmaniae, A. mixta australis and P. rufa appears to be very similar to that reported for the majority of iteroparous coastal temperate mysids throughout the world.     

The parasitoid fly Exorista japonica uses visual and olfactory cues to locate herbivore‐infested plants

Some parasitoid flies exploit odors derived from plants as olfactory cues for locating the food plants of host insects, but the role of visual cues associated with plants remains largely unknown. The generalist tachinid Exorista japonica Townsend (Diptera: Tachinidae) is attracted to odors derived from maize plants [Zea mays L. (Poaceae)] infested by the larvae of Mythimna separata (Walker) (Lepidoptera: Noctuidae). In this study, we examined the effects of visual parameters on the olfactory attraction of female flies to host‐infested plants. A paper plant model of one of four colors (blue, green, yellow, or red) was placed in front of a host‐infested plant, which was hidden behind a mesh screen in a wind tunnel. The landing rate of females was significantly higher on the green plant model than on the other three models. When an achromatic plant model of one of four gray scales (white, light gray, dark gray, or black) was tested, the response rate of females was significantly higher towards the white model and decreased as the brightness of models decreased. Few female flies responded to the green plant model without odors of the host‐infested plants. When the four color plant models were placed together in a cage filled with odors of host‐infested plants, females remained significantly longer on the green model than on the other three models. These results showed that E. japonica females preferred the color green when odors of the host‐infested plants were present and suggest that E. japonica uses visual as well as olfactory cues to locate the host habitat.     

Winter Host Plant Specialization in a Host-Alternating Aphid

The host alternating aphid, Rhopalosiphum padi (L.), feeds in summer on several different species of grasses but is monophagous on its winter host, Prunus padus L. The monophagy on P. padus could be a result of the restricted host range of the several different generations colonizing, or feeding, on this host during autumn–winter–spring. This study shows that the winter host plant specificity of R. padi is controlled mainly by the preference of the females remigrating (gynoparae) to the winter host, P. padus, in autumn. The other generations living on the winter host, i.e., sexual females, males, and spring generations, all accept a broader range of winter hosts. One alternative host plant, Prunus spinosa L., could be utilized by all generations associated with the winter host, except for the females remigrating at autumn.     

RAPD‐PCR DETECTION OF DNA POLYMORPHISM OF COTTON APHID*

Abstract The RAPDPCR technique was used to determine the DNA polymorphism of the aphid Aphis gossypii(Glover) collected from different host plants and in different seasons. Three primers were selected from 20 primers and used for cluster analysis based on the data of Nei's genetic distance (D). The results showed that the aphids on Chinese prickly ash differentiated obviously from the aphids on the other four host plants at DNA level. The seasonal population of cotton aphid might be clustered into three groups, i.e. the spring and autumn yellow colored aphids, the spring and autumn green colored aphids and the yellow dwarf form aphid in summer. However, the genetic relationship of dwarf form was more closely to the spring and autumn green colored aphid.     

Seasonal changes in the flight apparatus of winged females and sexual males of the aphid <Emphasis Type="Italic">Tuberculatus quercicola</Emphasis> (Hemiptera: Aphididae)

Tuberculatus quercicola (Matsumura) feeds on Quercus dentata Thunberg, and has mutualistic interactions with ants. Tuberculatus quercicola has two winged morphs in its life cycle, winged females appear in summer and sexual males appear in autumn. Previous studies have shown that wing loading (ratio of body volume to wing area) is higher for the winged females, because of ant attendance, resulting in extremely low dispersal. It is known that the nutritional quality of host plants is high in spring and autumn, when leaves are growing or senescent, and low in summer when leaves are mature. This study examined the effects of seasonal plant deterioration on the development of flight apparatus (wing size and flight muscle) of winged females and males. Moreover, field intercept traps were used to examine the extent of dispersal of males. The results showed that seasonal plant deterioration affected development of the flight apparatus of winged females, particularly flight muscle. Flight muscle development was significantly higher in winged males in autumn than in winged females. However, winged males were not caught in any of the traps. The different resource allocation to the flight apparatus of winged females and males is discussed.     

Temporal changes in host adaptation in the pea aphid, Acyrthosiphon pisum

Abstract.

• 1 Temporal changes in host adaptation were followed in a local population of the pea aphid, Acyrthosiphon pisum. Aphid clones were collected in one alfalfa and one clover field at three different times. In the spring, first-generation females were collected. Later, in the autumn, females belonging to the last parthenogenetic generation were collected. Lastly, sexual females were collected after mating in autumn and allowed to produce eggs which were hatched. The performance was evaluated on alfalfa and clover. The spring-collected individuals were also assessed on peas.
• 2 On the overwintering hosts clover and alfalfa, the clones performed best on the plant of origin, i.e. negative correlations in performance. Correlations between performance on the temporary summer host, pea, and that on clover/alfalfa were weak or nonsignificant.
• 3 Significant variation in host performance was found within both host fields at spring, which is a prerequisite for changes in clone composition due to selection/migration.
• 4 The clones from alfalfa showed an increase in mean performance on alfalfa between spring and autumn, whereas no changes among the clones from the clover field were observed. This difference in seasonal response between the two fields could have been the result of larger variation in performance among the alfalfa clones and/or a differential tendency to migrate among clones in both fields.
• 5 After sexual recombination in the autumn, mean performance in the alfalfa field returned to the spring level, probably as a result of emergence of new genetic combinations. In the clover field, mean performance did not change significantly over time.

     

Population persistence of the parasitoid fly Zaira cinerea (Fallén) (Diptera: Tachinidae) utilizing multiple host carabid beetles with different seasonality and quality

Zaira cinerea (Fallén) is a parasitoid fly (Diptera: Tachinidae) that attacks adult carabid beetles. To better understand mechanisms of population persistence in this species, we examined seasonality of host beetle abundance, the frequency of parasitism, and the timing of fly eclosion. In addition, we evaluated host quality using numbers of larvae or puparia per individual beetle as a measure of quality. The fly parasitized only large carabids (≥15 mm body length); the lengths of fly puparia reached 7.4–10.8 mm during development in beetle abdomens, and larger hosts are likely essential. Of the 18 large carabid species collected in this study, we chose two, Carabus maiyasanus Bates and Leptocarabus procerulus (Bates), because they were large and abundant (87% of total catch). The two carabids had different phonologies; C. maiyasanus was abundant from spring to summer, and its abundance dropped sharply in autumn, while L. procerulus was abundant in autumn and rare from spring to summer except July. Parasitism was observed in all the months from May to November except June, and adult flies eclosed more than once a year (in early summer, late summer, and mid‐autumn), indicating that the species is multivoltine. Host quality of L. procerulus was higher than that of C. maiyasanus. Carabus maiyasanus was mainly used as a host from spring to summer, and L. procerulus was used in autumn. Thus, adult beetles of one or both species are available over most of spring, summer, and autumn, allowing population persistence of this fly species over time.     

Effect of season of burn on shoot recovery and post‐fire flowering performance in the resprouter Stirlingia latifolia R. Br. (Proteaceae)

Abstract Stirlingia latifolia R. Br. is a proteaceous undershrub that is widespread in open woodlands and heathlands of the south‐west botanical province of Western Australia where it is subject to frequent fires, both natural and the result of fuel‐reduction burns. Shoots are completely destroyed by fire but regenerate rapidly by resprouting numerous new shoots from the root crown. Flowering is strongly triggered by fire with only sparse flowering in fire‐free periods. A study was undertaken to compare regrowth and flowering in populations of S. latifolia burnt in summer or autumn with populations burnt in spring as well as in unburnt population. Post‐fire flowering was recorded in 92% of plants burnt in summer/autumn compared with 73% of plants burnt in spring and less than 3% in populations that had not been burnt for more than 2 years. Plants burnt in summer/autumn resprouted an average of 8.5 shoots from their root crown, of which 93% developed an inflorescence. In contrast, spring‐burnt plants averaged only 5.9 shoots per plant with only 64% of these bearing an inflorescence. Ability to produce flowers was found to be related to plant age, with young individuals producing fewer or no inflorescences following spring burns in comparison with the more prolific flowering of similarly aged individuals following summer/autumn burns. Summer/autumn‐burnt plants also produced significantly longer inflorescence‐bearing shoots bearing a greater numbers of flower heads than those burnt in spring. Possible explanations for these results are given in the present report.     

The prediapause copulation and its significance in the butterflyEurema hecabe

In the pierid butterflyEurema hecabe, which shows seasonal polymorphism (summer and autumn morphs) and overwinters at adult stage, whether or not the prediapause copulation may be of usual occurrence and reproductively functional was examined. From the counts of the spermatophores carried by the females, it is clear that the prediapause copulation characteristically occurs in reproductively inactive females of the autumn corph. From behavioral observations in the field, mating partners of those females are mostly males of the summer morph rather than from the autumn morph. In autumn, males of the summer morph remained abundant and searched for females on the larval food plants. Furthermore, they mated frequently with autumn morph females. Autumn morph males seemed to be sexually less active or inactive before hibernation. Microscopic examinations of the spermathecae were made in mated autumn-morph females collected before and after hibernation. The results indicate that sperm is passed by the males at autumnal copulation. The sperm may be stored in the female reproductive tract and utilized for fertilization in spring. This supposition is strongly supported by field data; that is, once-mated autumn-morph females laid fertilized eggs in spring. Finally, physiological basis of the prediapause copulation, its adaptive signficance and the behavioral advantage inE. hecabe are discussed from the viewpoint of seasonal adaptation.     

Hibernation adaptation and eclosion synchrony in leaf-galling sawflies in subarctic Norway

The winter dormancy adaptation in gall-inducing sawflies is poorly known. Diapause termination and the following post-diapause quiescence enhance synchronous eclosion in spring. This is probably the most critical part in the life history in gall-inducing sawflies, as there is only a short phenological window of opportunity for mating and oviposition. In a 2?years’ study, diapause duration, termination, survival and eclosion synchrony were experimentally investigated for three gall-inducing sawfly species (Symphyta: Tenthredinidae: Pontania nivalis, P. glabrifrons and P. arcticornis). Field-collected galls, sampled from willows (Salix spp.) in early autumn, were kept under natural temperatures outdoors until next spring. Subsamples were successively transferred to the laboratory at 14-day intervals from October to April in a test of development time to eclosion and survival ratio. The time to eclosion decreased throughout the experiment, whereas the proportion successfully eclosed and eclosion synchronicity increased, all indicative of prepupae entering a diapause in early autumn. The diapause terminates midwinter, and the prepupae enter a post-diapause quiescence until the temperature in spring allows a direct development and contributes to a nearly synchronous eclosion. In all three species, males eclosed 1–2?days prior to females (protandry). We hypothesize that synchronous eclosion as well as protandry enhance mating and oviposition success. Our finding indicates that gall-inducing sawflies are well adapted to its harsh subarctic and arctic environment.     

Melanization of appressoria is critical for the pathogenicity of <Emphasis Type="Italic">Diplocarpon rosae</Emphasis>

Previous studies have shown the role of melanized appressoria in the pathogenicity of various fungi. Diplocarpon rosae is a worldwide outdoor fungal pathogen of rose plants causing black spot disease of rose leaves. To fully understand how this fungus colonizes its host, which is critical for the development of an efficient and sustainable disease management program, we studied the fungal (especially the appressoria) structures of D. rosae in detail at an early stage of infection. Using both microscopic and biochemical analyses, we observed strong melanized appressoria formation localized at the point of D. rosae penetration, which forms the pathogen–plant interface. Treatment of infected plants with melanin biosynthesis inhibitors (MBIs) prevented melanization of D. rosae appressoria and positively correlated with significant reductions in black spot disease symptoms, suggesting that melanization of appressoria might be a critical factor for the pathogenicity of D. rosae. Our findings were confirmed and validated by the lack of melanized appressorial ring formation on an artificial surface and on a D. rosae-non host plant system, Arabidopsis thaliana. Our findings suggest that localized melanization of appressoria is a crucial factor for the pathogenicity of D. rosae and treatment of the fungus with MBIs seems to be a promising disease management alternative for black spot disease of roses.     

Consistency of seasonal patterns of insect succession on pig cadavers at Yeongdo Island in Busan,Korea

Cadaver insects cause dead bodies to break down in ecological processes. Still, the knowledge has been accumulated slowly about the structure and role of the insect assemblages attending to death scenes. This study analysed the successional patterns of insects on pig cadavers in the spring, summer, and autumn from 2016 to 2019 at Yeongdo Island, Busan, South Korea. A sum of 71 insect species belonging to four orders and 21 families were sampled. Predominant insects were largely Diptera and Coleoptera. The majority of the flies were the calliphorids as Chrysomya pinguis (Walker) and Lucilia porphyrina (Walker). The most common beetles were Creophilus maxillosus (L.), Omosita japonica (Reitter), and Staphylinidae sp. regardless of seasons. Occurrence matrices were made from the successional patterns of insect species during 42 sampling intervals in the spring, 38 sampling intervals in the summer, and 26 sampling intervals in the autumn. Permutation analyses of the occurrence matrices showed that the patterns of succession were similar between spring 2016 and 2017 (P = 0.019), between summer 2016 and 2017 (P = 0.003), and between autumn 2016 and 2019 (P = 0.002). The result shows that there are clear patterns in succession between seasons, and provides the reference data to presume the death time, at least in the southeast part of South Korea.     

Seasonal Migration of Apolygus spinolae (Hemiptera: Miridae) between Grapevines and Herbaceous Plants

This study was conducted to verify the seasonal migration of Apolygus spinolae (Meyer-Dür) between grapevines and herbaceous plants. Overwintering eggs were hidden in the hair layer under grapevine bud scales. A. spinolae adults were captured on sticky traps in the grapevine yard from late spring to early summer, dwindled through the summer, and captured again in late fall. However, adults were observed from early summer in herbaceous plant fields. A. spinolae adults were abundant during the summer of July and August in the herbaceous field, and thereafter its density decreased through fall. A few or no A. spinolae was found on mesh-netted grapevines after the installation year of the mesh-net, which indicated that A. spinolae adults migrating to lay overwintering eggs during the autumn could not land at the grapevines because of the mesh-net. Damaged shoots by A. spinolae were concentrated near the edge of grapevine yards bordering the herbaceous plants. This distribution pattern of shoot damage was believed to be related to an oviposition behavior of A spinolae, reflecting that adults migrating from herbaceous plants lay eggs more frequently in grapevines adjacent to the summer host plants. Seasonal occurrence of A. spinolae in grapevine yards was suggested as follows: A. spinolae overwinter as eggs in dormant buds on grapevines and hatch in the spring. Nymphs feed on grapevines then develop to adults (spring population), and migrate to herbaceous plants. A. spimolae spends the summer on the herbaceous hosts (summer population). Then, adults migrate back to grapevines in late autumn and lay overwintering eggs.     

Hymenopteran specificity of Bacillus thuringiensis strain PS86Q3

The biological activity of Bacillus thuringiensis (Bt) strain PS86Q3 against five Hymenopteran species was determined by means of bioassays adapted to each species. Four species of sawfly that are important pests of conifers (Diprion pini, Gilpinia hercyniae and Pristiphora abietina) or ornamental plants (Arge rosae), as well as the non-target honeybee, Apis mellifera, were studied. Two out of the four sawfly species tested were found to be sensitive to PS86Q3 crystals or spore/crystal suspensions. A sporulated culture of this strain was moderately active on D. pini, and a complete bioassay with solubilized crystals was performed to estimate the LC₅₀ of 4.9 mg/ml. Pristiphora abietina was also found to be sensitive to PS86Q3, with an LC₅₀ of 1.6 mg/ml. By contrast, at the concentrations tested, PS86Q3 did not prove active on the remaining sawflies, G. hercyniae and A. rosae. The strain was administered orally to check its effects on honeybees which were fed sucrose solutions supplemented with a PS86Q3 sporulated suspension, in a field assay using commercial beehives. No significant differences in larval mortality (as deduced by comparing the number of larvae, pupae and empty cells) were found between the Bt and control treatments. On the basis of the results presented here, the suitability of PS86Q3 for the control of Hymenopteran pests, particularly sawflies, in terms of both potency and environmental safety, is discussed.