On the biology of anthocorid bugs (Heteroptera,Anthocoridae), predators of grass aphids in the forest-steppe zone of West Siberia

Four species of the heteropteran family Anthocoridae, Orius niger Wolff., O. majusculus Reut., O. minutus L., and Anthocoris confusus Reut., feeding on grass aphids on grains and bird cherry occur in the foreststeppe zone of Western Siberia. Orius niger and O. majusculus possess the greatest population numbers, with 98% of all the bugs collected in 1987 and 1988 belonging to these species. In 1998–2000, O. niger was predominant (97–100%). Data on the bionomics, seasonal abundance, feeding intensity, and role of anthocorids in the control of aphids are reported. Density of Orius bugs on wheat has been shown to be independent of the preceding culture. Permanent wheat is a preferable habitat of the predatory anthocorids. Mass reproduction of Orius bugs on pea-oat and alfalfa has been recorded.     

Seasonal cycles of noctuid moths of the subfamily Plusiinae (Lepidoptera,Noctuidae) of the Palaearctic: Diversity and environmental control

Analysis of data on seasonal development of noctuid moths of the subfamily Plusiinae shows that the control of their seasonal cycles is poorly understood. At the same time, the available data demonstrate considerable diversity of the seasonal patterns of Plusiinae species from different regions. The homodynamic type of seasonal development has been found in Trichoplusia ni and Ctenoplusia agnata of the tribe Argyrogrammatini and in Autographa gamma of the Plusiini. The seasonal development of these southern noctuids is accompanied by regular interzonal migrations of flying adults. When spreading northwards, they can produce a different number of annual generations, depending on the local climatic conditions, and establish temporary local populations whose longevity is limited by the available thermal resources. Adults of some species may fly back southwards, but it is more likely that individuals from temporary local populations cannot survive long winters and are destined to die. The heterodynamic type of seasonal cycles allows insects to survive in the regions with pronounced seasonality of climate. This type of seasonal development includes univoltine, multivoltine, and semivoltine seasonal cycles. Univoltine seasonal cycles with obligate diapause are known in Autographa buraetica, A. excelsa, and Syngrapha ain (Plusiini). Diapause provides tolerance to both low temperatures and a prolonged period when food is unavailable. In Syngrapha ottolenguii (Plusiini), the same result is achieved by inclusion of two photoperiodically controlled diapauses (winter larval and summer adult ones) into the life cycle. The semivoltine seasonal cycle has been reported in only one species of Plusiinae, namely Syngrapha devergens. Larvae of this moth overwinter twice before pupation. Multivoltinism is common in the tribe Plusiini. Depending on the latitude, different species of this tribe can produce up to four generations per year and overwinter as middle-instar larvae in the state of facultative diapause. However, the characteristics of diapause vary substantially between the species: diapause can be deep and stable (as in Diachrysia chrysitis, Plusiini) or unstable and thus not ensuring successful overwintering and steady population growth (as in Macdunnoughia confusa, Plusiini). The seasonal adaptations known in Plusiinae include migrations, winter and summer diapauses, photoperiodic control of larval growth rates, and seasonal polyphenism of larval body coloration. In general, seasonal adaptations of Plusiinae are determined by local environmental conditions and only loosely associated with the systematic position of particular taxa. Only the tribe Abrostolini stands apart from other taxa of Plusiinae: moths of this tribe differ not only in morphology but also in peculiarities of their seasonal development, because all the species of this tribe overwinter as pupae and their seasonal cycles are therefore different from those of the rest of Plusiinae.     

Are aphid parasitoids from mild winter climates losing their winter diapause?

Temperature is both a selective pressure and a modulator of the diapause expression in insects from temperate regions. Thus, with climate warming, an alteration of the response to seasonal changes is expected, either through genetic adaptations to novel climatic conditions or phenotypic plasticity. Since the 1980s in western France, the winter guild of aphid parasitoids (Hymenoptera: Braconidae) in cereal fields has been made up of two species: Aphidius rhopalosiphi and Aphidius matricariae. The recent activity of two other species, Aphidius avenae and Aphidius ervi, during the winter months suggests that a modification of aphid parasitoid overwintering strategies has taken place within the guild. In this study, we first performed a field survey in the winter of 2014/15 to assess levels of parasitoid diapause incidence in agrosystems. Then, we compared the capacity of the four parasitoid species to enter winter diapause under nine different photoperiods and temperature conditions in the laboratory. As predicted, historically winter-active species (A. rhopalosiphi and A. matricariae) never entered diapause, whereas the species more recently active during winter (A. avenae and A. ervi) did enter diapause but at a low proportion (maximum of 13.4 and 11.2%, respectively). These results suggest rapid shifts over the last three decades in the overwintering strategies of aphid parasitoids in Western France, probably due to climate warming. This implies that diapause can be replaced by active adult overwintering, with potential consequences for species interactions, insect community composition, ecosystem functioning, and natural pest control.     

Seasonal cycles in stink bugs (Heteroptera,Pentatomidae) from the temperate zone: Diversity and control

The paper reviews the diversity of seasonal cycles known in stink bugs (Heteroptera, Pentatomidae) from the temperate zone and is based on the data of 43 pentatomid species studied in detail up to date (Saulich and Musolin, 2011). All the seasonal cycles realized by pentatomids in the temperate zone can be divided into two large groups: univoltine and multivoltine cycles. In univoltine cycles, only one generation is annually realized. However, univoltinism of a particular species or population can be ensured by different mechanisms: its control can be endogenous (involving an obligate diapause) or exogenous (environmental, involving a facultative diapause). Furthermore, endogenously controlled univoltine seasonal cycles can include obligate embryonic (egg) diapause (e.g., Picromerus bidens and Apateticus cynicus), obligate nymphal diapause (e.g., Pentatoma rufipes) or obligate adult (reproductive) diapause (e.g., Palomena prasina, Palomena angulosa, and Menida scotti). Exogenously controlled seasonal cycles are more flexible. Many species that are multivoltine in the subtropical or warm temperate zones are univoltine further polewards. In this case, their univoltinism is controlled exogenously, or environmentally. The mechanism often involves such seasonal adaptations as photoperiodic response of facultative winter diapause induction with a high thermal optimum (e.g., Arma custos and Dybowskyia reticulata) or a high critical threshold of winter diapause induction response (e.g., Graphosoma lineatum). The seasonal cycles of some species include not only winter diapause (hibernation) but also summer diapause (aestivation). The diapausing stage can be the same (e.g., Nezara antennata has facultative adult winter and summer diapauses) or different (e.g., Picromerus bidens survives winter in obligate embryonic diapause and spends the hottest period of summer in facultative adult aestivation). All the multivoltine cycles follow the same general pattern, with one, two, or even more directly breeding generation(s) followed by a generation that enters winter diapause. However, this sequence may be complicated by incorporation of specific seasonal adaptations such as aestivation, migrations, different forms of seasonal polyphenism or polymorphism (e.g., seasonal changes of body color), etc. Many stink bugs demonstrate geographic clines of voltinism, producing several generations in the subtropical regions (environmentally controlled multivoltine development) and two or only one generation(s) polewards (environmentally controlled bi- or univoltinism). However, some species demonstrate a strictly bivoltine seasonal cycle: they always produce two annual generations, each with either winter or summer diapause. An example is Nezara antennata which produces two generations and enters facultative winter and summer diapauses. Semivoltine seasonal cycles last more than one year. They are not very rare among insects and are known in true bugs, but have not yet been recorded among pentatomids. Examples of different seasonal cycles are described and discussed in detail. Further discussion is focused on the ecological importance of photoperiodic and thermal responses in cases of natural or artificial dispersal of pentatomids beyond their original ranges. The phytophagous Nezara viridula and the predatory Podisus maculiventris and Perillus bioculatus are used as examples. An attempt is made to compare the phylogeny of Pentatomidae and distribution of realized patterns of their seasonal development. However, it is concluded that reconstruction of phylogenetic relationships cannot yet provide a sufficient basis for prediction of realized seasonal cycles. It is suggested that the terms uni-, bi-, multi-, and semivoltinism should refer to populations rather than species, since the realized patterns of seasonal development often differ between the northern and southern populations of the same broadly distributed species.     

Life cycles of 17 riffle-dwelling mayfly species (Baetidae,Heptageniidae, and Ephemerellidae) in central Japan

We described the life cycles of 17 riffle-dwelling mayfly species in a central Japanese stream. Both species of Baetidae (Alainites yoshinensis Gose and Baetis thermicus Uéno) and two of nine species of Heptageniidae (Ecdyonurus scalaris Kluge and Epeorus latifolium Uéno/l-nigrus Matsumura) in this stream were multivoltine (more than one generation per year). Seven other heptageniid species (two unidentified species of Cinygmula, Epeorus aesculus Imanishi, E. curvatulus Matsumura, E. ikanonis Takahashi, E. napaeus Imanishi, and Rhithrogena japonica Uéno) and all six species of Ephemerellidae [Cincticostella elongatula (McLachlan), C. nigra (Uéno), Drunella basalis (Imanishi), D. ishiyamana Matsumura, D. sachalinensis (Matsumura), and D. trispina (Uéno)] were essentially univoltine.     

Prolonged diapause of specialist seed-feeders makes predator satiation unstable in masting of<Emphasis Type="Italic"> Quercus crispula</Emphasis>

Quercus crispula (=Q. mongolica var. grosseserrata) is the predominant tree species in cool temperate, mixed broadleaf/conifer forests in northern Japan. We compared 11 years of data on acorn production in a population of Q. crispula, with data on seed-insect populations, to try to answer the following questions: (1) Does Q. crispula show a regular pattern of masting? (2) How long do principal seed predators remain in diapause? (3) How do the seed predators affect the pattern of predator satiation? Q. crispula showed a tendency to alternate bearing, with significant synchrony between individual trees. The principal acorn-feeding insects (Curculio spp. weevils), which infested 25%–70% of matured acorns, generally exhibited a prolonged diapause of 2 years. No significant negative relationship was found between the rate of injury by the weevils and the density of mature acorns, indicating that simple predator satiation fails due to the synchrony of the life-cycle of acorn-feeding insects and the periodical production of acorns. However, the rate of injury by the weevils was negatively correlated with the relative abundance of mature acorns to the number of weevil larvae that had matured 2 years previously. Thus, the proportion of sound acorns notably increased in a rich crop after a disturbance in alternate bearing. Prolonged diapause of specific seed predators is critical in determining the peak year of sound-seed production.     

Impact of multiple natural enemies on immature <Emphasis Type="Italic">Drosophila suzukii</Emphasis> in strawberries and blueberries

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) oviposits in ripening fruit, larvae render crops unmarketable, and significant economic losses can occur. Biological control research has focused on individual natural enemy species against immature D. suzukii. Here we combine two predators and an entomopathogenic nematode, expecting species complementarity and increased control of D. suzukii. In strawberries, Orius insidiosus (Say) (Hemiptera: Anthocoridae) plus Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) resulted in fewest D. suzukii (81% reduction), and in blueberries, results were similar (60% reduction), although H. bacteriophora was not as effective as in strawberries, which was likely due to drier substrate conditions. There was neither strong complementarity nor interference between predators, O. insidiosus and Dalotia coriaria Kraatz (Coleoptera: Staphylinidae). Inclusion of O. insidiosus resulted in 50% fewer D. suzukii than combinations without O. insidiosus. Control of D. suzukii can be improved with multiple natural enemies, and combinations of O. insidiosus with other agents (parasitoids, fungal entomopathogens) should be tested.     

Temperature and photoperiodic control of diapase induction in the ant <Emphasis Type="Italic">Lepisiota semenovi</Emphasis> (Hymenoptera,formicidae) from Turkmenistan

The ants L. semenovi has been found to belong to species with endogenous-heterodynamic seasonal life cycles with the obligate diapause induced predominantly by factors internal for a colony, whereas external ecological factors (photoperiods and temperature) produce merely modifying effects by accelerating or delaying the diapause onset. The photoperiodic and temperature regulation of diapause induction in larvae and queens is shown. Under effect of short days and low temperature the periods of larval pupation and queen oviposition in a colony are shortened markedly, i.e., the diapause of larvae and queens occurs earlier. The daily rhythms of temperature 15/25°C and particularly 20/30°C as compared with constant temperatures 20 and 25°C that correspond to the mean circadian temperatures of the thermorhythm, inhibit manifestations of the short day effects by stimulating the non-diapause development and increasing duration of the seasonal development cycle of ant colonies. The L. semenovi photoperiodic reaction is quantitative, as development and pupation of larvae and egg-laying of queens cease sooner or later under both the short and the long days, but in the latter case significantly later. Thus L. semenovi is one more example among very rare ant species that are revealed to have the photoperiodic regulation of the colony development seasonal cycle.     

Frugivore assemblage of <Emphasis Type="Italic">Ficus superba</Emphasis> in a warm-temperate forest in Yakushima,Japan

Understanding fig consumption patterns is important because figs are regarded as a keystone resource for many frugivorous species in the tropics. While much work on fig consumption has been conducted in tropical regions, temperate forests are particularly interesting for study owing to pronounced seasonal variations in temperature and community-level fruiting phenology. We studied frugivore consumption of Ficus superba (Miq.) Miq. var. japonica Miq syconia in a warm-temperate forest in Yakushima, southern Japan. We conducted 141 4-h focal observations of fruiting F. superba trees over 12 months. We aimed to assess the relative quantitative contribution of each species of frugivore to F. superba consumption over a year as well as factors affecting seasonal variation in consumption. Japanese macaques were by far the most important F. superba syconia consumer (87.6 %), followed by brown-eared bulbuls (5.0 %), and varied tits (4.2 %). Japanese macaques increased their F. superba consumption when the temperature was high and fruit availability (F. superba and other species) was low. Macaques seemed to avoid searching for rare F. superba trees during winter and used F. superba syconia as a fallback food during fruit scarcity. Birds showed the opposite pattern: they increased F. superba syconia consumption when the temperature was low and fruit availability was high. This was probably because birds eat insects as their main food in the summer and switch to fruit as autumn turns to winter.     

South African mouse shrews (<Emphasis Type="Italic">Myosorex</Emphasis>) feel the heat: using species distribution models (SDMs) and IUCN Red List criteria to flag extinction risks due to climate change

Five species of mouse or forest shrews (Myosorex) are endemic to South Africa, Lesotho and Swaziland, four of which (Myosorex varius, Myosorex cafer, Myosorex longicaudatus and Myosorex cf. tenuis) are associated with montane or temperate grassland, fynbos and/or forest habitats while a fifth (Myosorex sclateri) is associated with lowland subtropical forests. Due to their small size, specialised habitat, low dispersal capacity, high metabolism and sensitivity to temperature extremes, we predicted that, particularly for montane species, future climate change should have a negative impact on area of occupancy (AOO) and ultimately extinction risks. Species distribution models (SDMs) indicated general declines in AOO of three species by 2050 under the A1b and A2 climate change scenarios (M. cafer, M. varius, M. longicaudatus) while two species (M. sclateri and M. cf. tenuis) remained unchanged (assuming no dispersal) or increased their AOO (assuming dispersal). While temperate species such as M. varius appear to be limited by temperature maxima (preferring cooler temperatures), the subtropical species M. sclateri appears to be limited by temperature minima (preferring warmer temperatures). Evidence for declines in AOO informed the uplisting (to a higher category of threat) of the Red List status of four Myosorex species to either vulnerable or endangered as part of a separate regional International Union for Conservation of Nature (IUCN) Red List assessment.     

Effects of transgenic overexpression of diapause hormone and diapause hormone receptor genes on non-diapause silkworm

Diapause is a state of developmental arrest that is most often observed in arthropods, especially insects. The domesticated silkworm, Bombyx mori, is a typical insect that enters diapause at an early embryonic stage. Previous studies have revealed that the diapause hormone (DH) signaling molecules, especially the core members DH and DH receptor 1 (DHR1), are crucial for the determination of embryonic diapause in diapause silkworm strains. However, whether they function in non-diapause silkworm strains remains largely unknown. Here, we generated two transgenic lines overexpressing DH or DHR1 genes in a non-diapause silkworm strain, Nistari. Our results showed that developmental expression patterns of DH and DHR1 are quite similar in transgenic silkworms: both genes are highly expressed in the mid to late stages of pupae and are most highly expressed in day-6 pupae but are expressed at very low levels in other developmental stages. Moreover, the overexpression of DH or DHR1 can affect the expression of diapause-related genes but is not sufficient to induce embryonic diapause in their offspring. This study provides new insights into the function of DH and DHR1 in a non-diapause silkworm strain.     

Environmental control of the seasonal life cycle of a zoophytophagous mirid, <Emphasis Type="Italic">Adelphocoris triannulatus</Emphasis> (Hemiptera: Miridae)

Adelphocoris triannulatus (Stål) (Heteroptera: Miridae) is a zoophytophagous bug that inhabits grasslands and crop fields, and is widely distributed in eastern Asia. In this study, the seasonal occurrence and environmental factors controlling the seasonal life cycle of this bug were investigated in a local population in southern Kyushu, Japan. When insects were reared under different photoperiods at 20 and 25 °C, they produced diapause or nondiapause eggs depending on the photoperiod: when reared under short-day photoperiods (≤?13 h/day), females laid diapause eggs, whereas they laid nondiapause eggs when reared under long-day photoperiods (≥?14 h/day). Because the developmental duration of the pre-adult stages and maturation (minimum duration of one generation) is estimated to be approximately 30 days at summer temperatures, these results suggest that this bug has a multivoltine seasonal life cycle. In agreement with the laboratory results, only nondiapause eggs were produced until mid-August in the field, and an increasing proportion of diapause eggs were produced from early September. In addition to these findings, field sampling from spring to autumn in 2009 indicated that three or four generations were produced in one year. These results suggest that egg diapause plays a role in preventing nymphs of A. triannulatus from developing in winter, and thereby ensures the survival of the population in adverse seasons.     

<Emphasis Type="Italic">Cortinarius</Emphasis> sect. <Emphasis Type="Italic">Riederi</Emphasis>: taxonomy and phylogeny of the new section with European and North American distribution

Cortinarius is one of the most species-rich genera of mushroom-forming fungi. Based on phylogenetic and morphological evidence, Cortinarius, sect. Riederi, is introduced at sectional level (= subsect. Riederi sensu Brandrud & Melot). The taxonomy, phylogeny, ecology and distribution of not only mainly European but also including some North American taxa of this section are treated, which includes nine species and two varieties. Of these, three taxa are described as new (C. burlinghamiae, C. pallidoriederi and C. argenteolilacinus var. dovrensis). The sect. Riederi species possess morphological features similar to Phlegmacium group(s) and forms a phylogenetically isolated lineage, with no supported affinity to other phlegmacioid groups. Three taxa are known from both Europe and North America, two species are known only from North America and five only from Europe. Altogether, eight of the ten taxa are associated with conifers or northern (boreal-subalpine) deciduous trees (Betula spp.). Only two species occur in more temperate forests (Fagus forests), and no species have so far been found in thermophilous Quercus forests     

Spatial distribution shifts in two temperate fish species associated to a newly-introduced tropical seaweed invasion

The establishment of non-native habitat-forming seaweeds into new areas may trigger important changes in ecosystem functioning, yet their community and ecosystem-level effects remain largely understudied. Here we studied the spatial distribution of two common fish species (Xyrichtys novacula and Bothus podas) which are key components of communities in unconsolidated bottoms of temperate areas regarding the colonization of the newly-introduced tropical seaweed Halimeda incrassata in the Mediterranean Sea. We used a spatially-explicit before-after-control-impact model and a unique data-set formed by 6 years of fine-scale spatial information of fish and seaweed distribution and abundance. We demonstrate a long-term alteration on the spatial distribution of X. novacula characterized by a shift towards non-native H. incrassata beds, while no effect on B. podas. The introduction of the tropical seaweed H. incrassata has led to the re-distribution of X. novacula, potentially by harbouring a greater biodiversity of species at the base of the food-web through adding biogenic structure to an otherwise bare sediment. Our work demonstrates that non-native tropical habitat-forming species have the potential to maintain or even enhance fish abundance in unconsolidated bottoms in temperate areas potentially altering the functioning of native habitats.     

Growth and root dry matter allocation by pasture legumes and a grass with contrasting external critical phosphorus requirements

Background and aims

This work aimed to quantify the critical external requirement for phosphorus (P) (i.e. extractable-P concentration required for 90 % of maximum yield) for a number of temperate legume species and understand differences in dry matter allocation, P distribution and P acquisition efficiency among these species.

Methods

Shoot and root growth of five legume and one grass species was assessed in response to six rates of P mixed into the top 45 mm of soil in a pot experiment. Dactylis glomerata and Trifolium subterraneum were used as benchmark species; they are commonly grown together in mixed temperate pastures and have low and high critical external requirements for P, respectively. Growth was compared with four alternative legume species: Ornithopus compressus, Ornithopus sativus, Biserrula pelecinus and Trifolium hirtum, that have root morphologies better suited to soil exploration and nutrient acquisition than that of Trifolium subterraneum.

Results

Dactylis glomerata, Ornithopus compressus and Ornithopus sativus had maximum yields equal to or greater than Trifolium subterraneum but achieved this at rates of P less than half that of Trifolium subterraneum. Biserrula pelecinus and Trifolium hirtum had critical P requirements between that of Trifolium subterraneum and the Ornithopus species, but also had lower yields. Root dry matter of Dactylis glomerata and the Ornithopus species in the fertilised soil layer was only marginally changed in response to low P supply. In contrast, Trifolium subterraneum, Trifolium hirtum and to a lesser extent Biserrula pelecinus markedly increased root dry matter allocation to this soil layer. Species with lower critical P requirements were able to take up more P per unit root dry mass than those with higher critical P requirements, particularly at lower levels of P addition.

Conclusions

The high P acquisition efficiencies of the Ornithopus species and Dactylis glomerata were likely to have contributed to their low critical external P requirements. It was surmised that differences in root morphology traits underpin the differences in acclimation to low P stress and P acquisition efficiency among the species.

     

Floating-leaved macrophyte (<Emphasis Type="Italic">Trapa japonica</Emphasis>) drastically changes seasonal dynamics of a temperate lake ecosystem

Water chestnut (genus Trapa) is an annual floating-leaved macrophyte that produces dense beds known to drastically modify freshwater ecosystems. Although Trapa displays a distinct phenology that should alter the innate seasonal dynamics of ecosystems, the seasonality of these effects has rarely been investigated. Therefore, we examined seasonal changes in physicochemical conditions and assemblages of zoobenthos and zooplankton, and whether these changes were correlated with the rise and decline of dense beds of Trapa japonica in Lake Mikata, a temperate shallow lake in central Japan. Our results suggested that the formation of dense Trapa beds during summer resulted in hypoxia, which significantly decreased the abundance of Chironomidae and Oligochaeta in the benthic community, as well as that of Calanoida among zooplankton. When dense Trapa beds formed, we also detected growth of other taxa that were resistant to hypoxia, including Cladocera, Cyclopoida, Ostracoda, and Nematoda. Chlorophyll a concentration declined across the lake during summer, when dense Trapa beds formed. The decline in Trapa beds from autumn to spring resulted in increased dissolved oxygen concentration, chlorophyll a concentration, and invertebrate abundance (Chironomidae, Oligochaeta and Calanoida), as well as a decrease in taxa utilizing the dense Trapa beds. Our results suggest that the phenology of dense Trapa beds can drastically change the seasonal dynamics of physicochemical conditions and the lower components of the food web in a shallow lake ecosystem.     

Phylogeography of ten native herbaceous species in the temperate region of Japan: implication for the establishment of seed transfer zones for revegetation materials

Revegetation using native species requires the development of seed transfer zones that capture genetic distinctiveness and adaptive potentials while avoiding potential maladaptation and genetic contamination by exotic genotypes. Delineation based on phylogeographic information has recently been used to establish seed transfer zones; however, only a few herbaceous species that are suitable for revegetation have been investigated in the temperate regions of Japan. We investigated the phylogeography of non-coding regions of chloroplast DNA of ten native species in the temperate regions of Japan. Although no species showed clear-cut geographical distributions of the 2–14 haplotypes identified, spatially constrained Bayesian clustering showed two clusters in five species (Calamagrostis epigejos, Eragrostis ferruginea, Imperata cylindrica, Microstegium japonicum, and Microstegium vimineum) but not for others. Posterior modes of clusters for I. cylindrica and M. vimineum showed delineations at Chubu (the middle of Honshu Island), which divide the study region into northeastern and southwestern regions, indicating that these species had recovered from glacial refugia. Posterior mode of cluster for E. ferruginea showed that one consists of a coastal zone along the Pacific Ocean side of western Japan, while the other consists of the remaining area, indicating range expansion from south coast to north. Delineation of C. epigejos and M. japonicum were unclear. The mixed results indicated that establishing seed transfer zones for herbaceous species in Japan will require phylogeographical studies on a wide range of species that may be suitable for revegetation.     

Color polymorphism,development, and reproductive diapause of the multicolored Asian ladybird <Emphasis Type="Italic">Harmonia axyridis</Emphasis> (Pallas) (Coleoptera,Coccinellidae) females

Preimaginal development and maturation of females of two laboratory strains originated from two populations of the multicolored Asian ladybird Harmonia axyridis were investigated under laboratory conditions. Females of the autochthonous population from Irkutsk (Siberia) enter diapause under the short day conditions, whereas in females of the invasive population from Sochi (the Caucasus) photoperiodic induction of diapause is weak. The two populations also differ in the proportions of morphs: the population from Sochi is represented only by the morph succinea, whereas the population from Irkutsk is represented by the morphs succinea и axyridis with the predominance of the last one, which in our study was separated into two phenotypes, differed in the degree of melanization. Rearing of adults under the short day (12 h) conditions induced reproductive diapause in females of all the studied morphs and phenotypes of the Irkutsk population, whereas under the long day (18 h) conditions females of the morph succinea showed a slightly lower tendency to diapause. Evidently, the interpopulation differences in the responses regulating the seasonal cycle of the multicolored Asian ladybird are determined by genes that are not involved (or almost not involved) in the determination of the color polymorphism. The interpopulation differences in size and weight were quite substantial, whereas the differences between morphs and phenotypes were statistically significant in only some of our experiments. In combination with the literature data, these results suggest that the genes determining the color polymorphism in H. axyridis may have a pleiotropic effect on other traits including important eco-physiological parameters but this effect is relatively weak and manifests itself only against a particular genetic background and / or under particular environmental conditions.     

Dehydrins in Buds of Main Birch Species under Conditions of Karelia

The composition and seasonal dynamics of stress proteins-dehydrins in the buds of the main birch species (downy birch (Betula pubescens Ehrh.), silver birch (B. pendula Roth)) and its varieties (Karelian birch (B. pendula var. carelica (Mercklin) Hämet-Ahti)), growing in northwest Russia (on the example of the Republic of Karelia) were investigated for the first time. It was shown that the level of low-molecular dehydrins, mainly with a molecular mass of 17 kD, is subjected to major seasonal changes, regardless of the specific features of the birch. The maximal level of 17 kD dehydrin was formed during the autumn preparation of plants to dormancy and was persistently preserved during the cold period of the year. The content of medium-molecular weight dehydrins of 66–69 kD was almost at the same level all year round. Significant inter-and intraspecific polymorphism of the major dehydrins of 17 and 66–69 kD in the buds of downy birch, silver birch, and Karelian birch during dormancy was not found. The significant similarity in the composition of total proteins and dehydrins, as well as the uniform nature of their seasonal changes, mainly 17 kD dehydrin, indicates the phylogenetic proximity and similar mechanisms of adaptation of the main species of the genus Betula L. to the temperate continental climate of Karelia.     

Life history of <Emphasis Type="Italic">Stenopsylla nigricornis</Emphasis> (Hemiptera: Psylloidea: Triozidae) and phytohormones involved in its gall induction

Many phytophagous insects have an ability to manipulate plant tissue and induce galls, but the mechanism is not yet fully understood. Some insects have multivoltine life cycles, and each generation induces galls on different plant species or different organs in the same host. Such host-use patterns are interesting study subjects to clarify the gall-inducing mechanisms of insects. We focused on a multivoltine and gall-inducing psyllid Stenopsylla nigricornis Kuwayama (Hemiptera: Psylloidea: Triozidae), which is associated with Symplocos lucida Sieb. (Symplocaceae). Based on periodic field surveys in Kyushu, Japan, S. nigricornis is revealed to have a bivoltine life history. Then, we revealed that the spring generation induces galls on leaves, while the autumn generation does so on flower buds and overwintering leaf buds. We also analyzed phytohormones in normal plant tissue, S. nigricornis nymphs, and their galls. As a result, nymphs were discovered to contain much higher concentrations of isopentenyladenosine and its possible precursor, isopentenyladenosine riboside than plant tissues, strongly suggesting that the phytohormone is involved in gall induction by S. nigricornis. Because flower bud galls contained significantly lower concentrations of abscisic acid (ABA) than normal flower bud, the autumn generation nymphs are considered to regulate the ABA level and to promote the earlier opening of host flower buds.