Under seasonal conditions, Polydesmus angustus individuals born in the first part of the breeding season have a 1-year life cycle and those born later have a 2-year life cycle (cohort-splitting). In this study, 249 juveniles from four early broods (born in mid-July) and four late broods (born in September) were reared under similar laboratory conditions, to test for possible maternal influences on life-cycle duration. Development times of early- and late-born individuals were compared under four combinations of day length and temperature (16 h - 18°C, 16 h - 16°C, 12 h - 18°C and 12 h - 16°C). The results showed that development time varied significantly in response to day length, temperature and sex, but that of individuals in the early and late broods did not differ significantly (mean development times ± SE: 180 ± 6 and 183 ± 8 days, respectively). There were no significant interactions between birth period and other factors, indicating that the effects of day length, temperature and sex on development time were similar in early- and late-born individuals. This indicates that the extended life cycle of millipedes born late in the season is not maternally determined and that cohort-splitting is controlled entirely by the environmental conditions experienced by the offspring during their development. This conclusion is supported by the absence of significant variation in offspring live weight at birth measured at different times in the breeding season. The results are discussed in relation to the bet-hedging theory, which is often put forward to account for cohort-splitting in arthropods. In P. angustus, the results are consistent with either bet-hedging or adaptive plasticity, but further studies are required to decide which interpretation is correct. and Jean-François David, Jean-Jacques Geoffroy.
The possibility of storing natural enemies at low temperatures is important for the mass production of biological control agents. We evaluated the effect of different periods of cold storage on immature mortality, mummy body mass, lifespan, reproduction and flight capacity of the parasitoid Praon volucre (Haliday). One-day-old mummies of the aphid Macrosiphum euphorbiae (Thomas) containing pre-pupae of P. volucre were stored in a climatic chamber at 5°C and 70 ± 10% RH in the dark for different periods of time (5, 10, 15 and 20 days). The control consisted of mummies kept at 22 ± 1°C, 70 ± 10% RH and a 12 h photophase. Percentage adult emergence, mummy body mass, flight capacity and number of eggs in the ovarioles of P. volucre females decreased with increase in the period of storage, while the longevity of females was only slightly affected. Fat content of mummies, percentage of parasitized aphids and survival of progeny to emergence decreased with increase in the period of storage. Storage of P. volucre pre-pupae for up to 5 days at 5°C did not affect any of the above mentioned parameters. The fact that P. volucre pre-pupae can be stored for 5 days without loss of quality and for 10 days with only a slight loss facilitates the planning of mass production and shipment., Juracy Caldeira Lins, Jr. ... [et al.]., and Obsahuje seznam literatury
1_Maternal and grand-maternal photoperiodic responses of Trichogramma buesi, T. embryophagum, T. evanescens, T. piceum, T. principium, and T. telengai were investigated in laboratory conditions. During the experiment, grand-maternal and maternal generations developed at 20°C and one of the 4 photoperiodic regimes: L : D = 12 : 12, 14 : 10, 16 : 8, and 18 : 6 (in total, 16 combinations) while the progeny developed at L : D = 12 : 12 and one of the 3 thermal regimes: 13, 14, and 15°C. The proportion of diapausing individuals in the progeny of all the studied species was significantly dependent on the direct influence of temperature and on the maternal photoperiodic response. The influence of the photoperiodic conditions during development of the grand-maternal generation was statistically significant in 5 of the 6 studied species, being relatively weak in T. embryophagum and T. telengai, whose geographical ranges extend up to north-western regions of Europe (possibly, these wasps enter diapause so early that the grand-mothers of the diapausing generation develop under long day conditions). Comparative analysis showed that the thresholds of the maternal and grand-maternal photoperiodic responses coincided or almost coincided. The grand-maternal effect was stronger in the progeny of maternal females which developed under short day conditions than in those that developed under long day conditions. This pattern of interaction probably synchronizes the life cycle with seasonal changes because diapause is induced under decreasing day length and thus mothers of diapausing individuals develop at shorter daylength than do grand-mothers., 2_We conclude that the grand-maternal and the maternal effects on Trichogramma progeny diapause are based on one and the same photoperiodic response. In nature, the grand-maternal effect increases the proportion of diapausing individuals in the progeny of females which have developed under short day conditions during two generations, thus achieving a "cumulative" photoperiodic effect., Natalia D. Voinovich, Nina P. Vaghina, Sergey Ya. Reznik., and Obsahuje seznam literatury
The present study focused on the evolution of the karyotype in 21 taxa of the genus Isophya, which was done by mapping the location on the chromosomes of ribosomal RNA (rRNA) coding genes using fluorescence in situ hybridization (FISH) with an 18S rDNA probe and using silver staining (AgNO3) to evaluate the activity of major rDNA clusters. Since the chromosome number and sex determination do not vary in this genus, the above markers were used in a detailed comparison of the cytogenetic features of species of Isophya. The species analyzed were placed into three groups based on the location of rDNA on their chromosomes: (1) rDNA-FISH signals only on the two long pairs of autosomes, (2) rDNA-FISH signals on one long and one short pair of autosomes, and (3) rDNA-FISH signals on three to five different sized pairs of autosomes. These groupings partly correspond to the morphological groupings proposed in earlier studies. One long pair of autosomes frequently carried rDNA in all the Isophya species and probably is a plesiomorphic character for these taxa. The cytogenetic mapping revealed great variability among Isophya species in the chromosomal location of major rDNA clusters. Our results suggest that the observed variation in the number of rDNA clusters can be an important species-group specific phylogenetic marker. Analysis of 18S rDNA hybridization signals showed that the evolutionary dynamics of rDNA in this genus is remarkably high and accompanied by changes in the structure of chromosomes bearing rDNA at an inter- and intra-specific level. The telomeric sequence (TTAGG)n hybridized with the termini of most of chromosomes, however, some chromosome ends lacked signals probably due to a low copy number of telomeric repeats. and Beata Grzywacz, Anna Maryańska-Nadachowska, Dragan P. Chobanov, Tatjana Karamysheva, Elżbieta Warchałowska-Śliwa.
a1_There are few studies on the morphology and meiosis in the testicles of Heteroptera, but are extremely important, especially for the family Pentatomidae, because in some species in this family meiosis in the testicular lobes results in the production of non-fertile spermatozoa. With the aim of improving the level of understanding of this phenomenon the morphology of the testes and spermatogenesis in 10 species of Pentatomidae were recorded and compared. All of them have testes covered by a pigmented peritoneal sheath. In some species the internal membrane or just inside the peritoneal sheath is pigmented. The pigmentation of both membranes varied. The pigmentation of both was either yellow, or the internal membrane was yellowish and the external one reddish. When the membrane is pigmented, the colour is red or yellow. The number of lobes varied from 3 to 7, with intermediate numbers of 4 and 6. The size and diameter of the lobes are similar in all the species studied, except Proxys albopunculatus, in which the diameter of the third and fifth is smaller than that of the other lobes. The behaviour of the cells during spermatogenesis was the same in all lobes of most species, except in P. albopunctulatus, in which the harlequin lobe is absent and the cells in lobes 4 and 6 exhibited characteristics different from those of cells in lobes 1-3 and 5. Chlorocoris complanatus and Loxa deducta (both Pentatominae) have a harlequin lobe (lobe 5). The chromosome complements recorded were: 2n = 12 (10A + XY) in Dichelops melacanthus and Edessa collaris, 2n = 14 (12A + XY) in C. complanatus, Edessa meditabunda, Ladeaschistus sp., Loxa deducta, P. albopunctulatus, Piezodorus guildinii and Thyanta perditor and 2n = 16 (14A + XY) in Edessa affinis. Thus, this study extends the knowledge of characteristics, such as the pigmentation of the peritoneal sheath, number of testicular lobes, the occurrence of meiotic cells in some, a2_testicular lobes, and the chromosome complements of the family Pentatomidae., and Hederson Vinícius De Souza, Aline Sumitani Murakami, Juliana De Moura, Elisângela Cristiane De Almeida, Inaiá Fernandes Gallego Marques, Mary Massumi Itoyama.
Fifteen different mitochondrial haplotypes of the mtDNA gene COI encoding cytochrome C oxidase subunit I were identified in the 127 individuals of Adalia bipunctata studied. Two mitochondrial haplotypes, H9 and H10, differed greatly from the others. The mitochondrial polymorphism in A. bipunctata is ancient, though its age remains to be evaluated. It is shown that mitochondrial haplotypes H9 and H10 and others coexisted in the original population of A. bipunctata before it spread throughout Eurasia from Western Europe to the Baikal Area, and before the differentiation of the subspecies A. bipunctata fasciatopunctata, which differs from the European form in its elytral pattern. In order to evaluate the possible origin of the ancient mitochondrial haplotypes in the gene pool of A. bipunctata sequences of the mtDNA gene COI and of the rRNA second internal transcribed spacer of the four species of Adalia: A. bipunctata, A. decempunctata, A. frigida and A. tetraspilota, were compared. It is suggested that infection with Rickettsia had an important role in the preservation of the mitochondrial haplotypes H9 and H10 during the evolution of Adalia., Ilya Zakharov, Elena Shaikevich., and Obsahuje seznam literatury
a1_Quantitative behavioural traits associated with egg-laying, such as the level of selectivity for host-supports and the size of egg clutches, are generally thought to be of great importance for the subsequent survival and development of offspring. These quantitative traits, however, are often difficult to assess reliably by direct observation in the field. This is particularly the case when the insects are very tiny, which is the case for most galling and leaf mining insects. However, a new approach, the "Melba" procedure, allows the indirect inference of these quantitative traits, using easily recorded field-data only. Application of this diagnostic procedure to a large series of samples of beech leaves (Fagus silvatica), harbouring either a leaf miner, Phyllonorycter maestingella (Lepidoptera: Gracillariidae) or one or the other of two galling insects, Mikiola fagi or Hartigiola annulipes (Diptera: Cecidomyiidae) indicates that the leaf miner differs significantly from the two species of galling insect in term of combined values of host-acceptance ratio and average clutch-size, while the two gall-inducing species remain substantially undistinguishable from each other according to these traits. Thus, the galling insects (i) show stronger selectivity for a host than does the miner at any given average clutch-size and (ii) show larger average clutch-size at any given level of selectivity. That is, for at least these three species, the galling insects show a greater level of selectivity when choosing leaves to oviposit on but, then, tend to lay larger egg-clutches. These differences may be due (i) to the gall-inducing process requiring far more of leaf tissues than being simply palatable, which makes it likely that galling species will be more selective in their choice of leaves than leaf miners and (ii) to the capacity of galls to become nutrient sinks, which may help explain why the galling insects laid larger, a2_egg clutches. However, whether these trends can be regarded as general rather specific to this particular case, depends on the outcome of future studies on other groups of insects with similar life histories., and Jean BÉGUINOT.
This study of the proteins in the silk of the summer and winter cocoons of the horse chestnut leaf miner Cameraria ohridella revealed they can inhibit protease activity. The inhibitory activity of the summer silk was higher against both the fungal proteinase K and bacterial subtilisin than that of the winter silk. Also, the winter silk was more effective in inhibiting proteinase K than subtilisin. Further, it was demonstrated that some of the silk proteins are glycosylated probably by mannose carbohydrates. An electron microscopy study of the cocoons revealed the presence of silk fibres with different diameters in some pupal chambers. and Veronika Hněvsová, Dalibor Kodrík, František Weyda.
A positive correlation between the parental effort of a male and female should promote stable biparental care. In order to prevent infanticide male and female burying beetles are said to guard against intruders cooperatively and the presence of a male partner is said to increase the probability of successful defence. However, this hypothesis is supported only by indirect evidence. In this study this hypothesis is tested by direct observation. Whether the intruder was male or female, contests between the same and the opposite sex occurred, although there were few contests between resident females and intruding males. In addition, resident pairs tended to win irrespective of the sex of the intruder, although it is reported that among burying beetles large beetles usually win intra-sexual contests. In the presence of a partner, a small resident can defend a carcass against a large con-sexual intruder. These results suggest that by means of biparental cooperation burying beetles can repel stronger intruders and supports the hypothesis that the threat of infanticide is the primary explanation for extended biparental care in these beetles. and Seizi Suzuki.
The effects of landscape attributes on Lepidoptera communities were studied in an agricultural area in Calabria (S-Italy). The association between a set of community descriptors and landscape metrics was determined using a multi-scale approach. Lepidoptera were sampled using yellow sticky traps in 10 olive groves. The landscape in 5 concentric areas, with radii from 250 to 1250 m, around each sampling site was analyzed. The composition and configuration of the landscape were calculated both at the landscape and class level based on the main classes of land use. The following life-history traits of Lepidoptera were considered: (i) dispersal ability of adults, (ii) habitat preferences and (iii) diet breadth of larvae. An index of community vulnerability was calculated by combining life-history traits and species diversity. There were no significant correlations between any of the landscape metrics and species richness or between species richness and abundance of natural or semi-natural habitats. However, life-history traits were significantly correlated with some landscape metrics, depending on the spatial scale. Most notably, landscape diversity is positively correlated with community vulnerability. The presence of sensitive species in olive orchards, but not species richness per se, is associated with the presence of natural and semi-natural habitats in the surrounding agricultural landscape. In conclusion, responses of communities to landscape changes are more likely to be revealed by an analysis of ecological traits, than species richness. In particular, the vulnerability index, used in this joint analysis of the main ecological traits, seems to be an effective descriptor of the relationships between communities and landscape., Stefano Scalercio ... [et al.]., and Obsahuje seznam literatury