Reduced oviposition by ladybirds in the presence of tracks of fourth instar larvae owing to the presence of oviposition deterring pheromones is well established across many genera. However, deterrence, if any, by other life stages has not been well investigated, in particular the effect of conspecific presence. The present study investigates the effects of conspecific presence and semiochemicals of conspecific life stages (eggs, fourth instar larvae, pupae, adult males and females) on oviposition by five ladybird (Coleoptera: Coccinellidae) species, viz. Coccinella septempunctata, Coccinella transversalis, Cheilomenes sexmaculata, Propylea dissecta and Anegleis cardoni. Results reveal that the presence of life stages inhibits oviposition and the inhibition is density-dependent, although the degree of inhibition is species-specific. Surface semiochemicals of eggs and larval and adult tracks also show density-dependent inhibitory effects. Moreover, the semiochemicals in tracks (oviposition deterring pheromones) and egg surface semiochemicals are not similar, indicating semiochemical parsimony. Of all species tested, C. transversalis and C. septempunctata were the most and the least responsive to both conspecific presence and semiochemicals, respectively., Geetanjali Mishra ... [et al.]., and Obsahuje seznam literatury
In the Mediterranean area the orthopterans Calliptamus barbarus barbarus, Dociostaurus maroccanus and Tettigonia viridissima are considered to be pests of major economic importance crop plants. The aim of the present study was to evaluate the area of leaf of vine, cotton and potato plants consumed by these Orthoptera at two temperatures. Leaf area was determined for each plant species before the leaves were provided to the insects. Virgin male and female adults were allowed to feed on a leaf of each plant species and the area of leaf consumed was determined after 24h at 25 and 30°C. Results showed that temperature had a significant affect on consumption by both males and females of all the species examined, and it was higher at 30°C. The influence of plant species was not significant for C. barbarus barbarus. D. maroccanus and T. viridissima, however, consumed a greater area of potato leaves than of the other species of plants. Females consumed more food than males in all the species tested. The results of the present study provide a first approximation of the area of leaf consumed and the potential loss of foliage these plants might suffer if attacked by the three species of Orthoptera tested., Spyridon A. Antonatos, Nikolaos G. Emmanuel, Argyro A. Fantinou., and Obsahuje seznam literatury
Transgenic lines of silver birch (Betula pendula) carrying the sugar beet chitinase IV gene were used to study the effects of the heterologous expression of a transgenic chitinase on the performance of lepidopteran herbivores. The effect of wounding the leaves of birch on the performance of lepidopteran larvae and the growth of trees was also studied. Larvae of Orgyia antiqua L., Lymantriidae, and Phalera bucephala L., Notodontidae, were separately fed on the leaves of transgenic and wild-type birch, and their performance measured using nutritional indices. The relative growth rate (RGR) of O. antiqua larvae fed transgenic leaves was significantly lower than that of larvae fed wild-type leaves. Furthermore, there is little evidence that transgenic chitinase affects survival but it was lowest for the group of larvae fed leaves with the highest expression of chitinase IV. Wounding did not have a significant effect on the performance of the larvae or on the growth of the branches of the trees. The growth of branches of particular transgenic lines, however, was significantly associated with tree line. The performance of P. bucephala larvae fed leaves of transgenic and wild-type birches did not differ. The leaves used in both experiments from transgenic trees were shorter than those from wild-type trees. Using transgenic birch expressing sugar beet chitinase IV to improve the resistance of birch to fungal diseases can have negative effects on O. antiqua larvae feeding on the leaves of these birches. P. bucephala, however, was not similarly affected, which indicates that these two ecologically similar lepidopteran species may differ in their response to transgenic chitinase., Liisa Vihervuori ... [et al.]., and Obsahuje seznam literatury
Nově objevený předchůdce současných sépií - egyptosépie (Aegyptosaepia lugeri) spojuje křídové linie dvoužábrých hlavonožců, zastoupených rodem Ceratisepia a třetihorní přímé předchůdce řazené k rodu Belosaepia. Přítomnost znaků křídových předků a pozdějších eocénních zástupců vytváří pozoruhodnou mozaiku, ve které můžeme spatřovat analogii např. se slavným jurským archeopteryxem. Nálezy z paleocénu Egypta poskytly řadu odpovědí na různé otázky evoluce sépiidů, mj. na období a způsob vzniku „rostra“ sépií, jejich paleogeografický původ a biotopy, ve kterých tito hlavonožci vznikali. Nálezy egyptosépií výrazně posouvají vznik přímé linie sépií dále do minulosti, k blízkosti hranice křída/terciér, proslavené velkým vymíráním suchozemských i mořských organismů., Aegyptosaepia (Aegyptosaepia lugeri) - a newly discovered direct ancestor of recent Sepia stock constitutes a link between the Cretaceous coleoid cephalopod Ceratisaepia and the Tertiary Belosaepia. The mixture of morphological features of both, the Cretaceous ancestors and the Eocene descendents creates an interesting mosaic. The Paleocene fossil records from Egypt have provided a lot of answers concerning the sepiid evolution, the period of sepiid “rostrum” origin, palaeobiogeography and the original habitat of these coleoids. The Aegyptosaepia record significantly extended the stratigraphic range of direct Sepia ancestors towards the Cretaceous / Tertiary boundary, an important mass extinction event for marine and non-marine biotas., Martin Košťák., and Obsahuje seznam literatury
Thelytokous parthenogenesis is a type of sex determination in which females are produced from unfertilized eggs. Genetic and endosymbiont-induced forms of thelytoky have been described in the Hymenoptera. Our study has revealed that Wolbachia, Cardinium, Spiroplasma and other endosymbionts are probably absent in Iberian populations of harvester ants, Messor barbarus and Messor capitatus (Hymenoptera: Formicidae: Myrmicinae) and are thus not involved as factors in the sex determination of these two species. Our results lend weight to previous suggestions that bacterial parthenogenesis induction in Hymenoptera is probably limited to the reproductive systems of chalcidoid and cynipoid parasitoid wasps (Hymenoptera: Apocrita: Chalcidoidea and Cynipoidea, respectively)., Paloma Martínez-Rodríguez ... [et al.]., and Obsahuje seznam literatury
Hexamerins are hemocyanin-related haemolymph proteins that are widespread in insects and may accumulate to extraordinarily high concentrations in larval stages. Hexamerins were originally described as storage proteins that provide amino acids and energy for non-feeding periods. However, in recent years other specific functions like cuticle formation, transport of hormones and other organic compounds, or humoral immune defense have been proposed. During evolution, hexamerins diversified according to the divergence of the insect orders. Within the orders, there is a notable structural diversification of these proteins, which probably reflects specific functions. In this paper, the different possible roles of the hexamerins are reviewed and discussed in the context of hexamerin phylogeny., Thorsten Burmester, and Lit
In order to determine when during the development of H. armigera CYP6B6 is expressed, we measured the width of the head capsule, the length of the body and weight of the different life stages of the cotton bollworm reared under laboratory condition. The larvae took about 20 d to complete their development under these conditions, the pre-pupae about 4 d, pupae about 9 d, and the adults lived for about 9 d and the eggs took about 4 d to hatch. Knowing this it was possible to determine the pattern of cytochrome P450 CYP6B6 expression at different stages in the life cycle of H. armigera using real-time quantitative polymerase chain reaction (RT-qPCR). The CYP6B6 gene was expressed in all the developmental stages of the cotton bollworm. The results indicate that the level of expression was lower in the egg, pre-pupal, pupal and adult stages than in larvae. The level of expression of CYP6B6 decreased from the 1st to the 3rd instar larva, with the lowest level recorded in the 3rd instar larvae and then increased reaching its highest value in 6th instar larvae. A similar trend in the expression of CYP6B6 was detected using immunohistochemistry. As the results show, more efficient control of the cotton bollworm can be achieved if insecticides are applied when the larvae of H. armiger are in the 3rd instar, because at that stage the eat little food and there is a low level of detoxifying enzymes in the larvae., Xuetao Zhang ... [et al.]., and Obsahuje seznam literatury