Alien vs . Predator - the native lacewing Chrysoperla carnea is the superior intraguild predator in trials against the invasive ladybird Harmonia axyridis

The alien invasive ladybird Harmonia axyridis (Pallas) (Coleoptera Coccinellidae) is a biological control agent of aphids and in the larval stage it is a very voracious and superior intraguild predator over most native ladybirds studied, except the large species Anatis ocellata (L.). We report the first aphidophagous insect - lacewing Chrysoperla carnea (Stephens) (Neuroptera Chrysopidae) - which is a superior intraguild predator, despite its smaller size, over the aggressive invasive ladybird H. axyridis in larval stage. We also observed high survival rate of hoverfly larvae Episyrphus balteatus (De Geer) and Epistrophe eligans (Harris) (Diptera Syrphidae), when exposed to ladybird larvae. Ladybird larvae were killed by lacewing larvae, individually paired in an empty Petri dish without food and water, in 50% of the cases when second instar larvae of both species were tested, in 94% of the cases with third instar larvae, and in 52% of the cases when third instar larvae of the lacewing were paired with much heavier fourth instar ladybird larvae. Larvae of the hoverflies E. balteatus were partially (27% of cases) and E. eligans strongly (76% of cases) protected against intraguild predation (= were not killed during experiment) by H. axyridis, but they never killed ladybird larvae. These results suggest that high biological diversity could be retained in crops and natural habitats, with possible synergistic effects on pests

Termination of diapause in the lime seed bug Oxycarenus lavaterae (Heteroptera: Lygaeoidea: Oxycarenidae)

The true bug Oxycarenus lavaterae has spread northwards through Europe from the Mediterranean at the beginning of the 21st century. Temperature and photoperiod in particular countries are important for the prediction of further spread. The timing and conditions for the termination of winter diapause in Bulgarian and Czech populations of O. lavaterae were determined. The progress in diapause development in the Bulgarian population was monitored by changes in the duration of the pre-oviposition period under long day (18L : 6D) conditions, which decreased gradually from October to June from 98 to 10 days at 20°C and 62 to 9 days at 25°C. There was no change in the photoperiodic response around the winter solstice in December/January, as is recorded for many other temperate insects. Instead, most overwintering females of O. lavaterae transferred to the diapause-promoting short-day photoperiod (12L : 12D) at 25°C did not start to oviposit even though they lived up to one year. The percentage of females that oviposited under short day conditions gradually increased from December to May, but only reached approximately 50% at most. In the Czech Republic, the number of individuals observed resting in overwintering aggregations on tree trunks gradually decreased up to early June. This bug seems remain in diapause until lime trees flower and their seeds become available

Isopsylloborine A, a new dimeric azaphenalene alkaloid from ladybird beetles (Coleoptera: Coccinellidae)

A new dimeric azaphenalene alkaloid, isopsylloborine A (2), has been isolated from the ladybird beetles Halyzia 16-guttata and Vibidia 12-guttata, and its structure determined by 2D NMR methods. It is a double bond isomer of the recently described psylloborine A (1), which is also present in these beetles as a minor alkaloid.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Hyperaspine, a new 3-oxaquinolizidine alkaloid from Hyperaspis campestris (Coleoptera: Coccinellidae)

A new 3-oxaquinolizidine alkaloid (3R*,4aR*,6S*,8R*)-6-hydroxy-3-methyl-8- pentylperhydropyrido[1,2-c][1,3]oxazine 6-(pyrrole-2-carboxylate) (hyperaspine) has been isolated from the ladybird beetle Hyperaspis campestris and its structure determined by 2D NMR and MS methods. © 2001 Elsevier Science Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Détermination de structure et biosynthèse d'alcaloïdes défensifs de Coccinellidae

La famille des Coccinellidae est divisée en sept sous-familles et comprend plus de 5200 espèces répandues dans le monde entier. En règle générale, les coccinelles souffrent peu des prédateurs, ce qui peut être attribué à une vaste gamme de défense (capacité d’envols brusques, camouflage, mimétismes, aposématisme, etc.). Ces insectes disposent également de défenses chimiques : en cas de danger, l’adulte s’immobilise dans une attitude imitant celle d’un individu mort (thanatose) et sécrète des gouttelettes d’hémolymphe au niveau des articulation tibiofémorales de ses pattes par un mécanisme appelé « saignée réflexe ». Chez de nombreuses coccinelles, cet exsudat contient un ou plusieurs alcaloïdes dont l’amertume et la toxicité sont considérés, dans une large mesure, comme une protection vis-à-vis des prédateurs potentiels. Ces alcaloïdes présentent une grande diversité de structures et se rattachent à des squelettes aussi différents que ceux de l’azaphénalène, de l’homotropane ou des azamacrolides. Afin de mieux cerner l’évolution des mécanismes de défense chimique chez ces insectes, nous avons entrepris l’étude du contenu alcaloïdique de Hyperaspis campestris. L’hémolymphe de cette coccinelle contient un alcaloïde nouveau, l’hyperaspine dont la structure a été déterminée sur la base de ses propriétés spectroscopiques. Parallèlement à ces études, nous avons mis au point une méthode de production in vitro de la coccinelline et de l’adaline au moyen de broyats de tissus. Cette technique nous a permis d’explorer de manière plus précise le schéma de biosynthèse de ces molécules, de déterminer l’origine biogénétique de l’atome d’azote ainsi que l’organe responsable de la synthèse des alcaloïdes chez ces insectes

Détermination de structure et biosytnthèse d'alcaloïdes défensifs de Coccinellidae

II est actuellement clairement établi qu'un grand nombre de coccinelles doivent leur protection, du moins en partie, a la présence d'alcaloïdes répulsifs et parfois toxiques dans leur hémolymphe. La plupart de ces substances sont biosynthetisées de novo ou, plus rarement, acquises a partir de leur alimentation (séquestration). Ces alcaloïdes présentent une grande diversité de structures et se rattachent a des squelettes aussi différents que ceux de l’azaphénalène, de l’homotropane, de la pipéridine, des azamacrolides... Dans le cadre de l’étude de l’évolution des mécanismes de défenses chimiques de ces insectes, nous avons entrepris l’étude de la biosynthèse des deux alcaloïdes présents chez les coccinelles Adalia-bipunctata et Adalia-decempunctata: l’adaline et l’adalinine. Dans un premier temps, nous nous sommes proposes de déterminer la relation biogénétique existant entre ces deux alcaloïdes. Pour ce faire, nous avons synthétisé de l’adaline dont la chaîne pentyle est perdeutériee. Puis, afin d'établir 1'origine polyacétate de 1'adaline, nous avons mis au point un schéma de dégradation conduisant a l’isolement du carbone du carbonyle de cette molécule. Parallèlement a ces études nous avons étendu le nombre d'espèces étudiées du point de vue de leur contenu alcaloïdique. II s'agit de Vibidia duodecimguttata, d'Halizia 16-guttata et de Harmonia axyridis. Les deux premières contiennent des alcaloïdes doubles de structures complexes proches de la psylloborine A. La troisième contient majoritairement de 1'harmonine

Nα-quinaldyl-L-arginine ·HCl, a new defensive alkaloid from Subcoccinella-24-punctata (Coleoptera, Coccinellidae)

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Transgenic resistance of Bulgarian potato cultivars to the Colorado potato beetle based on Bt technology

Colorado potato beetle, Leptinotarsa decemlineata Say, is the most destructive insect pest of potatoes. When the population of beetles is high, plants can be completely defoliated and commercial potato production is nearly impossible without control of the beetle. The beetles have shown a tremendous ability to develop resistance against insecticides. Previously, a biotechnology approach to control Colarado potato beetle based on the use of the synthetic Bt gene was developed. In this article, a transformation procedure for three commercial Bulgarian potato cultivars was developed and potentially commercial transgenic lines have been selected based on field resistance to Colorado potato beetles and yield. Plants were transformed with the Bacillus thuringiensis (Bt) cry3A gene using Agrobacterium-mediated transformation. 110 plants from the three cultivars were regenerated and tested by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). The Cry3A protein accumulation varied across the transgenic lines, rating from very low to 71.5 $\mu$g/g fresh weight. 21 transgenic lines expressing the Cry3A protein at levels above 10 $\mu$g/g fresh weight were tested in two successive years in filed conditions at two different locations of the country. All transgenic lines compared with the controls, nontransgenic potatoes from the respective cultivar, were consistently protected from foliar damages from all developmental stages of the beetle. The comparison of all properties of the tested transgenic lines, including variety phenotypes and tuber yield, allowed the selection of the most promising 2–3 lines per cultivar. Selected lines produced tuber amounts 80–100% higher compared with the control, non-transgenic plants. Those lines were grown for mass propagation during the third year of field experiments. The presence of the transgene in these lines was confirmed with the use of primers specific to the transgene by polymerase chain reaction (PCR). Additionally, the results from the insect bioassay showed that these lines were highly resistant to insect feeding, leading to 100% of mortality of larval populations. In summary, we generated potentially commercial potato lines highly resistant to Colorado potato beetle using Bt technology that may have a profound impact on development of sustainable agriculture in Bulgaria. This is one of the several agriculture biotechnology products entirely developed and tested in Bulgaria