Eleven species of parasitoids were found to attack 7 species of wheat aphids in Iran. The Simpson's Index of diversity (D) used to compare the aphidiine diversity in various cereal crop systems in geographically different regions of Iran ranged from 0.197 to 0.488, depending on locality. There were significant differences among species diversities at different altitudes. The central highlands (1000-1500 meters above mean sea level) were the areas with the most diverse aphid parasitoid complex, differing significantly from that at lower and higher altitudes. We found that altitude explained about 10% of the cereal aphid parasitoid distribution pattern in Iran. Species of the genus Aphidius Nees were the most abundant and widely distributed. These were Aphidius rhopalosiphi De Stefani, Aphidius uzbekistanicus Luzhetski, Aphidius colemani Viereck and Aphidius matricariae Haliday. A. uzbekistanicus, Ephedrus plagiator (Nees) and Ephedrus persicae Froggat were encountered mainly on the plains at lower altitudes. Diuraphis noxia (Kurdjumov) was mainly recorded at higher altitudes in Iran along with its dominant parasitoid species, Diaeretiella rapae (MIntosh). The fact that Iran is close to the presumed area of D. noxia origin (Central Asian submountains) could be very important in further biological control efforts against this pest aphid. According to our results, Aphidius ervi Haliday is a very rare parasitoid of cereal aphids in Iran, which contrast with its high abundance in Europe and North America.

Experimental hybridization of X0 and XY chromosome races of the brachypterous grasshopper P. sapporensis did not reveal pre-zygotic reproductive isolation. However, a partial zygotic barrier was found between the X0-standard race from Shimokawa and XY-standard chromosome race from Akan. Approximately 40% of embryos from females crossed with males from other chromosome races developed parthenogenetically, the remaining embryos were normal heterozygotes. Adult F₁ males and females from crosses of this type had properly developed testes and ovaries. Non-sister associations and other irregularities in meiosis were not observed in male meiosis. Crossing experiments demonstrated that hybrids between X0 and XY races occur to some extent. The absence of a hybrid zone between the X0 and XY chromosome races may be the result of selection against heterozygotes. Crosses between the XY-Tanno and X0-standard (Teine) subraces resulted in F₁ and F₂ generations in spite of the many chromosome differences between them such as a X-A translocation and fixed pericentric inversions in four pairs of autosomes. These results do not support the hypothesis that chromosomal differences play a key role in restricting gene flow between the X0 and XY races of P. sapporensis.

In many insects, mate finding is mediated by volatile sex pheromones, but evidence in nabids is still fragmentary. The role of odour-mediated sexual attraction in two nabid species, Nabis pseudoferus and N. rugosus, was studied in a Y-tube olfactometer. Females of the two species were significantly attracted by odours of conspecifics males, and males of N. rugosus, but not of N. pseudoferus, were attracted by odours of conspecific females. Odours of conspecifics of the same gender were unattractive. These results suggest the existence of male pheromones in both species and a different female pheromone in N. rugosus.

The blister beetle genus Teratolytta, belonging to the tribe Lyttini, is revised and a classification is proposed. Two main sections of the genus - one including five groups of species and the other three groups - are tentatively defined. Four new species from Eastern and Southern Anatolia are described (T. carlae sp. n., T. dvoraki sp. n., T. monticola sp. n., T. taurica sp. n.), and a key to the 17 recognized species is proposed. A diagnosis of the species as well as taxonomic remarks are proposed, and a catalogue of localities is presented. In particular, Teratolytta tricolor (Haag-Rutenberg, 1880) comb. n. is re-established as a distinct species, T. cooensis G. Müller, 1936 is confirmed as a synonym of T. gentilis (Frivaldszky, 1877), T. bytinskii Kaszab, 1957 as a synonym of T. senilis (Abeille de Perrin, 1895), and T. holzschuhi Dvořák, 1983 is proposed as a synonym of T. eylandti Semenow, 1894; some infraspecific forms are referred to the variability of T. gentilis and T. flavipes (Mulsant & Rey, 1858). The first instar larva of T. gentilis is described and figured, and the sexual behaviour of this species is also briefly studied.

The development of Adalia bipunctata larvae feeding on the grain aphid Sitobion avenae was investigated at 15, 20 and 25°C and two different levels of food supply. Increased temperatures accelerated development and reduced mortality rates. A reduced food supply slowed down development and increased mortality at all life stages. The total food intake of larvae ranged from 24-65 mg, which is equivalent to up to 190 aphids. Larvae compensated for low food supply by reducing development rates, high prey exploitation efficiencies, reaching up to 100%, and by high prey-biomass conversion efficiencies, reaching over 40%. The findings are discussed under the aspect of suitability of A. bipunctata as a biological control agent for greenhouse-specific aphid pest species.

The rose grain aphid, Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) is one of the three most important cereal aphid species in Europe. High temperature is detrimental for the survival of this species. Detailed experiments were conducted on the effect of high temperature (27, 28, 29, 30, 31, 31.5, 32.5, 33 and 34°C), period of exposure (2, 3, 4, 6 and 8 h per day for 1, 2, 4, 6 days) and developmental stage (2nd, 3rd, 4th instar nymph and adult) on the survival of the aphid. The results show that all three factors significantly affect survival. Temperatures over 29°C for 8 h significantly reduced survival, which decreased generally as the temperature increased. The survival was inversely related to the period of exposure. Exposing aphids to 32.5°C for 4 h or longer significantly reduced survival. Mature aphids had a lower tolerance of high temperatures than nymphs. Periods of high temperature experienced by 4th instar and adult aphids can greatly affect their survival. The value of these results for forecasting and determining control thresholds, the effect of global warming on cereal aphid abundance and the dropping off behaviour of the aphids are discussed.

Selected life-history traits of an oonopid spider, Triaeris stenaspis Simon, which has been introduced into greenhouses in Europe, were investigated. Spiders were reared in the laboratory under constant physical and dietary conditions, and followed from egg to death. The spiders passed through 3 juvenile instars, each lasting approximately a month. The adult stage lasted on average 6 months, which is 54% of the entire life cycle. The mortality in each juvenile instar was similar. Five morphological characters were recorded for each instar, which provided a reliable means of identifying the developmental stages. All spiders developed into females and although kept isolated they laid fertile eggs, which indicates thelytokous parthenogenesis. Eggs were always enclosed in a disc-shaped egg-sac, each containing 2 eggs. Total fecundity was on average 27 eggs and rate of laying eggs decreased with age. Fecundity was positively correlated with adult longevity. Fertility was rather low, approximately 59%. It was negatively correlated with fecundity but not related to longevity. Low fertility appears to be the only cost of parthenogenetic reproduction. There was considerable genotypic variation in all traits studied compared to that in sexually reproducing spiders. There were no apparent maternal effects on all the traits studied. Using molecular methods proved that parthenogenesis in T. stenaspis is not induced by the endosymbiotic bacteria, Wolbachia sp. or Cardinium sp.

The winter survival of three closely related univoltine heteropterans that overwinter as adults, Nabis rugosus, N. ericetorum and N. pseudoferus was investigated. After 150 days of low temperature treatment (3-5°C, 16L : 8D, r.h. 70-80%) more males than females died. The mortality rate ranged from 88.8 to 93.8% in males and from 54.2 to 60.7% in females. However, these sexual differences in mortality did not differ significantly across the three species and populations of different geographic origin. It remains a general question whether this considerable evolutionary stability in the sex-specific investment into reproduction and survival phylogenetically conserved or frequently evolves anew to similar levels in separated populations and species. In Nabis rugosus, the relative loss of body mass during overwintering was up to 37.8%. This reflects dramatic somatic costs of adult overwintering and indirectly supports the hypothesis that food supply during overwintering is important for some heteropteran predators. However, body mass before overwintering did not significantly explain the survival pattern in N. rugosus in either sex. The similar sex-specific survival rate of overwintering adult nabids regardless of species and geographic origin can be useful for studies on population dynamics of nabids in agroecosystems and biocontrol.

A modified method for clearing, staining and mounting plant-inhabiting mites is proposed. With this method, all mites can be cleared with a single agent and mounted in a single medium. The stain added to the mounting medium enhances the clarity of the fine structures of soft-bodied mites under phase contrast and more significantly under bright field microscopy.

Emerging parasitoids of aphids encounter secondary plant chemistry from cues left by the mother parasitoid at oviposition and from the plant-feeding of the host aphid. In practice, however, it is secondary plant chemistry on the surface of the aphid mummy which influences parasitoid olfactory behaviour. Offspring of Aphidius colemani reared on Myzus persicae on artificial diet did not distinguish between the odours of bean and cabbage, but showed a clear preference for cabbage odour if sinigrin had been painted on the back of the mummy. Similarly Aphidius rhopalosiphi reared on Metopolophium dirhodum on wheat preferred the odour of wheat plants grown near tomato plants to odour of wheat alone if the wheat plants on which they had been reared had been exposed to the volatiles of nearby tomato plants. Aphidius rhopalosiphi reared on M. dirhodum, and removed from the mummy before emergence, showed a preference for the odour of a different wheat cultivar if they had contacted a mummy from that cultivar, and similar results were obtained with A. colemani naturally emerged from M. persicae mummies. Aphidius colemani emerged from mummies on one crucifer were allowed to contact in sequence (for 45 min each) mummies from two different crucifers. The number of attacks made in 10 min on M. persicae was always significantly higher when aphids were feeding on the same plant as the origin of the last mummy offered, or on the second plant if aphids feeding on the third plant were not included. Chilling emerged A. colemani for 24 h at 5°C appeared to erase the imprint of secondary plant chemistry, and they no longer showed host plant odour preferences in the olfactometer. When the parasitoids were chilled after three successive mummy experiences, memory of the last experience appeared at least temporarily erased and preference was then shown for the chemistry of the second experience.

The current laboratory study was designed to evaluate the effect of abiotic and biotic factors such as temperature, light intensity, relative humidity and host age on biological and ecological characteristics of Aphelinus asychis (Walker) parasitizing Aphis gossypii (Glover). The traits studied were developmental duration, mortality, sex ratio, longevity, fecundity and host feeding. A. asychis can completely develop and reproduce at temperatures 18°C and 30°C, light intensities of 1000 and 7000 lux and relative humidities of 30% and 60%. Temperature had a significant effect on the developmental duration as well as on the percentage and longevity of females, while mortality from mummification to emergence, fecundity and host feeding were only slightly affected. Relative humidity only affected the developmental duration of A. asychis. Light intensity had mostly affected the biological and ecological traits of A. asychis. High light intensity resulted in a shorter developmental duration, higher incidence of females and longer life span of the female parasitoid. A high tolerance to climatic variations and life cycle well adapted to this aphid host are properties that make it likely that A. asychis could be used for the biological control of the cotton aphid in greenhouses.

The relations between the patterns of discontinuous gas exchange cycles (DGCs) and water loss were investigated in non-chilled diapausing pupae of the white cabbage butterfly Pieris brassicae kept at room temperature (22-24°C) in Petri dishes. An electrolytic respirometer, combined with an infrared (IR) actographic device was used for the simultaneous recordings of metabolic rate, cyclic release of carbon dioxide (bursts), passive suction inspirations (PSIs) and body movements. The patterns of cyclic gas exchange in four- and five-month-old non-chilled diapausing pupae varied individually to a considerable extent. About 40% of the pupae displayed long DGCs lasting 1-3 h, while the interburst periods were characterised by rare and almost regular large PSIs succeeding at intervals of 1-4 min. Nearly 30% of the pupae exhibited short DGCs lasting 3-5 min, while between the bursts there occurred unclear frequent gas exchange microcycles. Standard metabolic rate (SMR) did not reveal significant differences between long DGCs and short DGCs ranging from 32-56 (mean 47.6 ± 4.6) ml O₂ g^-1 h^-1, and 28-61 (mean 44.95 ± 5.3) ml O₂ g^-1 h^-1, respectively. The mentioned levels of SMR were characteristic of diapausing pupae.
Water loss in pupae with long DGCs was determined gravimetrically to be 0.29 ± 0.1 mg g^-1 day¹. At the same time, water loss in pupae that showed only short DGCs and irregular microcycles was 1.73 ± 0.31 mg g^-1 day^-1, which was significantly higher than in individuals characterised by long DGCs. We suggest that water loss in the non-chilled diapausing pupae may depend significantly on the patterns of cyclic gas exchange: long cycles and rare but deep PSIs exerted a marked water conserving effect.

Karyotypes of the polyploid parthenogenetic species Saga pedo from four localities in France and the Republic of Macedonia were constructed and compared. All these karyotypes consist of 70 chromosomes, which is more than twice that in other species of the genus. The chromosomes differ from each other, making the matching of homologues difficult. Karyotypes of French specimens are similar, except for differences in the heterochromatin. Compared to that of the Macedonian specimens those from French specimens differ by the shortening of a single chromosome. The difficulty experienced in identifying tetrads and even pairs of chromosomes indicates that either many chromosome rearrangements have occurred since the polyploidisation event(s) or that the addition of quite different genomes is the cause. On the other hand, that the karyotypes are similar indicates a common origin of both the Macedonian and French populations. Thus, most chromosome changes preceded the separation from their common ancestor. Both the DNA content and chromosome analyses suggest that the S. pedo karyotype is pentaploid and not tetraploid as previously proposed. This odd ploidy number rules out the hypothesis that it could only have originated by endoreduplication. It is more likely that it originated by the association of five copies of the 14,X haploid karyotype, which exists in the gametes of the closely related species, S. campbelli and S. rammei (male / female 2n = 27, X / 28, XX). Fertilization of a parthenogenetic 56, XXXX female by a 14, X spermatozoa could have resulted in the last increase in ploidy.

Phylogenetic relationships within the diving-beetle subfamily Hydroporinae are not well understood. Some authors include the genus Pachydrus Sharp, 1882 in the tribe Hyphydrini, whereas others are in favour of excluding Pachydrus from the Hyphydrini and placing it in its own tribe, Pachydrini. Larval characters have been underutilised in phylogenetic studies, mainly because the larvae of many taxa within the family are unknown. In this study, the phylogenetic relationships of Pachydrus are studied based on a cladistic analysis of 34 taxa and 122 morphological larval characters. For this purpose, larvae of P. obesus Sharp, 1882 are described and illustrated in detail for the first time, with particular emphasis on morphometry and chaetotaxy. First and second instars for the genus were unknown. The results support a monophyletic origin of the tribe Hyphydrini excluding Pachydrus, based on four unique character states. On the other hand, Pachydrus is resolved as the sister group of the Hydrovatini. These results suggest Pachydrus should not be placed in the Hyphydrini. Given that the Hyphydrini minus Pachydrus is a distinctive clade, based on this study, it seems useful to recognise this group as Hyphydrini. Including Pachydrus in Hyphydrini would leave the tribe with a single larval apomorphy, as most characters present in the Hyphydrini and Pachydrus are also present in the Hydrovatini. However, in the absence of larvae of Heterhydrus Fairmaire, 1869 and of a more comprehensive and inclusive analysis, we do not propose a formal exclusion of Pachydrus from Hyphydrini at this stage. Pachydrus is a highly distinctive genus within the Hydroporinae and is characterised by several larval apomorphies.

Cannibalism and intraguild predation (IGP) are both common phenomena amongst aphidophagous coccinellids and serve as vital alternative feeding strategies which can prolong survival during periods of aphid scarcity. A reduction in essential prey density and the acceptance of conspecific or heterospecific prey are likely to have a considerable influence on both larval development and adult reproduction. However, little is known about the legacy of larval diet on adult performance. This paper considers the effects of the diet provided to larvae of Harmonia axyridis (Pallas) and Adalia bipunctata (Linnaeus) (Coleoptera: Coccinellidae) on the reproductive output of the resulting females. Results showed that larval diets, including treatments analogous to competition and IGP, did not affect adult longevity, ovipositional lag, proportion of eggs laid in clutches or ovariole number in H. axyridis or A. bipunctata. However, some variation in the maximum clutch size and oviposition rate was seen. A larval diet of unlimited aphids resulted in the largest clutches of eggs being laid by both species. The total number of eggs laid over 30 days was largest for H. axyridis when larvae were reared on unlimited aphids or limited aphids supplemented with either conspecific or heterospecific eggs, whereas oviposition was lower for A. bipunctata females that had received conspecific or heterospecific eggs in their larval diets. The results have also enabled us to make some general comparisons of reproductive parameters between the two species, and to refute the hypothesis that the maximum clutch size laid by a female ladybird is limited by the number of ovarioles within an ovary. We conclude that IGP of A. bipunctata eggs by H. axyridis larvae has a positive effect on reproductive output and is therefore likely to further contribute to the spread and increase of H. axyridis in Britain.

A new genus Diphyonyx is proposed here for a previously unrecognised lineage of geophilid centipedes. It is distinct from other geophilids in its unique combination of morphological characters, including the peculiar shape of the pretarsus of the legs on the anterior part of the trunk. The type species D. conjungens (Verhoeff, 1898), comb. n., is redescribed in detail and its geographical distribution updated (Balkan Peninsula, Anatolia, Crimea). Included in Diphyonyx are also D. sukacevi (Folkmanová, 1956), comb. n., and D. garutti (Folkmanová & Dobroruka, 1960), comb. n., both from southern Russia. D. garutti is raised here to species rank.

The second and final part of a revision of the European species of the genus Rhabdomastix Skuse, 1890 is presented. The subgenus Rhabdomastix s. str. is revised. Seven species are redescribed, Rhabdomastix (Rhabdomastix) japonica Alexander, 1924, R. (R.) laeta (Loew, 1873), R. (R.) borealis Alexander, 1924, R. (R.) edwardsi Tjeder, 1967, R. (R.) subparva Starý, 1971, R. (R.) hirticornis (Lackschewitz, 1940) and R. (R.) beckeri (Lackschewitz, 1935). Three new synonyms are proposed. Lectotypes of four pertinent nominal species are designated. Descriptions are provided of six species, viz. R. (R.) laetoidea sp. n. (Czech Republic, Slovakia, Bulgaria, Ukraine), R. (R.) crassa sp. n. (France, Czech Republic, Slovakia), R. (R.) corax sp. n. (Bulgaria, Greece), R. (R.) eugeni sp. n. (France, Switzerland, Germany, Czech Republic, Slovakia, Italy, Romania, Bulgaria, Greece, Ukraine, Armenia), R. (R.) filata sp. n. (Bulgaria, Greece, European Russia, Turkey, Georgia, Armenia) and R. (R.) georgica sp. n. (Georgia). Male and female terminalia are illustrated for all the species, and a key to species is appended.

The structure of the holocentric chromosomes of the rosy apple aphid, Dysaphis plantaginea (2n = 12), and pear-grass aphid, Melanaphis pyraria (2n = 8), was studied using C-banding, NOR, Giemsa and fluorochrome staining, and fluorescent in situ hybridization (FISH). Contrary to the equilocal distribution of heterochromatin typical of monocentric chromosomes, in both species C-banding evidenced a tendency of highly repetitive DNAs to be restricted to the X chromosomes. Silver staining and FISH, using a 28S rDNA probe, located rDNA genes on one telomere of each X chromosome, the only brightly fluorescent C-positive sites revealed by CMA₃ staining, whereas all other heterochromatic C-bands were DAPI positive. Both species showed a noticeable amount of rDNA heteromorphism. Mitotic recombination is proposed as a possible mechanism responsible for the variation in size of rDNA.

A complete profile of the 20-hydroxyecdysone (20-HE) titer, development and endocrine events from 1^st instar to pupation of the larvae of non-diapause-destined (NDD) and diapause-destined (DD) tasar silkworm, Antheraea mylitta Drury (Lepidoptera: Saturniidae) was studied. Diapause is induced by short days of 11 hr photophase coupled with <= 24°C prevailing in September-November. Diapausing pupae produce adults in July (>= 12h light, >= 26°C) and one generation is completed by August. The growth rate during the course of development of larval instars decreases and instar durations are inversely related to the body weight at the time of initiation of a larval instar. A growth compensation mechanism operates during the development of the larval instars. The growth rate was higher in early instars (1^st to 4^th) in both generations. The DD larvae complete the final instar in 16 days followed by a spinning stage of 13 days. The NDD larvae complete the final larval instar in 9 days followed by spinning stage of 6 days and spend 14 days in the pupal stage. The signal to release the prothoracicotropic hormone (PTTH) is related to critical body weight of larvae. From 1^st to 4^th instar, pre-ecdysial peaks of 20-HE were recorded in both NDD and DD generations. The programme for undergoing diapause was initiated during 3^rd instar and induced by a sudden decrease in the level of 20-HE in the DD generation. Two peaks of 20-HE are required for the larval-pupal transformation, first at the wandering stage and the second at cuticle formation.

Many insect species attracted to fermenting sap often fight for access to this resource, which results in the establishment of interspecific dominance hierarchies. In one such system, the hornet Vespa mandarinia (Hymenoptera: Vespidae) behaviourally dominates during the daytime and several subordinate species avoid aggressive interactions in various ways. In order to elucidate the interspecific variation in competitor-avoidance behaviour and its subsequent effect on foraging success, the behaviour of species of hornets, beetles and butterflies at patches (exudation spots) in Japan was recorded. The percentage of individuals that succeeded in visiting a patch following departure from one, or an attempted visit, or after waiting near a patch for >= 10 s, did not differ greatly among species, despite the distinctive differences in dominance between V. mandarinia and the other species. These results suggest that subordinate species may be equally effective at foraging for sap as the dominant species. The competitor-avoidance behaviour differed among the species. Vespa crabro and satyrine butterflies mainly avoided competition by actively moving away from competitors. The beetle Rhomborrhina japonica (Coleoptera: Scarabaeidae) often remained close to an occupied patch and waited for the occupant to leave, whereas V. ducalis and nymphaline butterflies used both tactics. The different costs associated with fighting or flight may have determined the differences in the foraging tactics of the species studied and behavioural switching in those species utilising both tactics.

The water strider Aquarius paludum inhabits the surfaces of a wide variety of freshwater habitats both temporary and permanent. It can also live on the surface brackish-water around river mouths. Exposure to a brackish rather than freshwater environment may affect a range of adult and offspring life-history traits. In a two-stage experiment A. paludum offspring from fresh- (F) and brackish-water (B) populations were obtained and their offspring reared in either a fresh- or brackish-water (0.45% NaCl) environments. The four offspring treatment groups (F-F, F-B, B-F, B-B) varied in terms of the parental and offspring rearing environments. The effect of parental and offspring rearing environment on longevity, fecundity and flight was assessed. Offspring reared in a brackish environment throughout their larval and adult stages had a reduced longevity and egg production. The flight activity of the offspring originated from the brackish-water population was maintained when they were reared in a brackish environment, but inhibited when they were exposed to freshwater. Our results suggest that the life-history strategies depend critically on the degree of salinity in both the current environment and that of their parents.

Dehydration of Onymacris unguicularis (Haag) for 10 days at 27°C resulted in a weight loss of 14.9%, and a 37% decrease in haemolymph volume. Although there was an overall decrease in the lipid content during this period, metabolic water production was insufficient to maintain total body water (TBW). Rehydration resulted in increases in body weight (6.2% of initial weight), TBW (to normality), and haemolymph volume (sub-normal at the end of rehydration). Despite an increase of 44.0 mg in the wet weight of O. unguicularis after drinking for 1h, there was little change in the water content at this time, although the total lipid content increased significantly. Increases in haemolymph osmolality, sodium, potassium, chloride, amino acid and total sugar concentrations during dehydration were subject to osmoregulatory control. No evidence of an active amino acid-soluble protein interchange was noted during dehydration or rehydration. Haemolymph trehalose levels were significantly increased at the end of rehydration (relative to immediate pre-rehydration values), indicating de novo sugar synthesis at this time. Osmotic and ionic regulation was evident during rehydration, but control of OP during haemolymph-dilution is poor and accomplished largely by the addition to the haemolymph of free amino acids and solute(s) not measured in this study. There was little mobilization of sodium and chloride ions from storage sites at this time. The lesser osmoregulatory ability of Onymacris unguicularis and perhaps earlier susceptibility to osmotic stress, a significantly high normal blood glycerol level (relative to other diurnal adesmiine tenebrionids), and a water storage mechanism associated with synthesis of fat, probably all contribute to the development of fog-basking behaviour in this species. Water gain in O. unguicularis during periods of relative drought is probably largely accomplished by a greater food consumption.

Chequered blue butterfly, Scolitantides orion (Lepidoptera: Lycaenidae) has severely declined in many parts of Europe and is currently red-listed in many countries. We studied the population structure and turnover of the species in a lake-island system in a National Park in eastern Finland over a three-year period. The incidence of the chequered blue on the suitable islands (n = 41) and habitat patches (n = 123) was high: an average of 82% of the islands and patches were occupied over the three year period. At the island scale, the annual population turnover rate was 17%, with an extinction and colonization rate of 7% and 10%, respectively. At the patch scale, the annual population turnover was 16%, with 7% extinction and 9% colonization rate. Islands that were occupied over the three year period had a larger area of suitable habitat than islands in which turnover events were observed. At the patch scale, turnover events were observed in small and poorly connected patches. Patchy occurrence of the host plant and observed extinction-colonization dynamics suggest that the chequered blue population confirms a metapopulation structure. Although the local populations are small, the observed high patch occupancy and balanced population turnover indicates that the metapopulation is not in immediate risk of extinction.

The aim of this study was to show that the kind of AKH-mobilized energy substrates in insects can be predicted on the basis of the results obtained with the application of heterologous, i.e. inter-species, AKHs. Four different AKHs, the Locmi-AKH-I inducing hyperlipaemia and hyperglycaemia in Locusta migratoria, Tenmo-HrTH inducing hyperglycaemia in Tenebrio molitor, and Pyrap-AKH and Peram-CAH-II inducing hyperlipaemia in Pyrrhocoris apterus were used, firstly in conspecific tests, secondly in all possible species-AKH combinations, and finally in individual applications on the test species, the cotton bug Dysdercus cingulatus. Since each of the AKHs induced hyperlipaemia in D. cingulatus adults, we predicted that lipids are the only energy substrates which are mobilized in this species by its native AKH. The accuracy of this prediction was subsequently confirmed by the structural identification of the native D. cingulatus AKH and conspecific application tests. The proposed methodical approach can serve as a suitable monitoring system for determination of the kind of energy substrates mobilized by native insect AKHs until the structure of the hormone is identified.

The benefits for offspring of attendant adult were investigated in the stag beetle Figulus binodulus. The initial growth rate of third-instar larva was significantly higher when the larvae were in a nest with adults compared to those in a nest without adults. The difference in growth rate is reflected in adult body size. Although the presence of adult beetle generally benefited the offspring, the adults did eat some of the larvae. Filial cannibalism was the primary cause of juvenile death in nests with adults. Mortality was lower in nests with adults related to the juveniles compared to nests with unrelated adults, suggesting that infanticide of nest mates may be inhibited. These results suggest that F. binodulus has a level of sociality and nest mate recognition that is very rare in stag beetles. Social behaviour may be more advantageous for small stag beetles than fighting.

One factor limiting the adoption of aphidophagous coccinellids in augmentative biological control is cost-effective mass production. The use of factitious foods may lower production costs by reducing space and manpower requirements for mass rearing of the predator and its prey and by enhancing mechanization of rearing procedures. The objective of this study was to compare the efficiency of food conversion, consumption indices and growth rates of first to fourth instars of Adalia bipunctata when fed either a mixture of Ephestia kuehniella eggs and fresh bee pollen, or on the natural prey Myzus persicae. Larval survival did not differ among treatments, averaging 80 and 90% on the respective diets. Mean dry body weights of the coccinellid were significantly lower on M. persicae than on the factitious food only for second instars and the pre-pupal stage. Dry food consumption by the predator throughout larval development averaged 20.61 mg on factitious food and 14.82 mg (corresponding to an average of 284 third and fourth instars) on M. persicae. The efficiency of conversion of ingested food for total larval development averaged 25 and 30% on factitious food and aphids, respectively. The relative growth rate of the larval instars was higher on aphids, whereas the consumption index was higher on the mixture of E. kuehniella eggs and pollen. An additional experiment showed that rearing the previous instars on the factitious food had no substantial effect on aphid consumption in the fourth instar. The study suggests that this factitious diet may be an appropriate food source for mass rearing A. bipunctata.

The sibling species H. yedoensis Takizawa coexists sympatrically and simultaneously with H. axyridis only on pine trees in Japan. To elucidate the mechanisms enabling coexistence of these two sympatric sibling species, a laboratory experiment was performed that focused on differences in their maternal investment through eggs and the role of sibling cannibalism. The egg size (volume) of H. yedoensis was 24.91% larger than that of H. axyridis. Cluster size in H. axyridis was significantly larger than that in H. yedoensis; however, the total number of eggs and oviposition cost (by volume) per female in H. yedoensis were not significantly different from those in H. axyridis, although total number of clusters tended to be slightly higher in H. yedoensis than in H. axyridis. The percentage of undeveloped eggs per cluster in H. yedoensis was not significantly different from that in H. axyridis, whereas the percentage of developed eggs with delayed hatching per cluster was significantly larger in H. yedoensis than in H. axyridis. Moreover, the cost of sibling cannibalism per hatched larval cluster in H. yedoensis (worth 4.43 sibling eggs) was 3.36 times larger than that in H. axyridis.Therefore, maternal investment through egg and sibling cannibalism in developed eggs with delayed hatching are more intense in H. yedoensis than in H. axyridis, implying a higher larval survival rate through higher ability of prey capturing at the first instar. The results in this study suggest that the higher survival rate and accelerated development in H. yedoensis by the two maternal investments, i.e., a large egg and intense sibling cannibalism of developed eggs with delayed hatching, may play an important role in sympatric coexistence with the aggressive aphidophagous ladybird beetle H. axyridis.

A cytogenetic study of bisexual species belonging to the genera Cirrorhynchus, Dodecastichus and Otiorhynchus is presented in order to confirm their taxonomic position. The karyotype characterization was accomplished by an analysis of mitotic and meiotic chromosomes after differential staining, namely by C-banding, silver impregnation, DAPI and CMA₃. A review of the cytogenetic data for the tribe Otiorhynchini contributed to knowledge of chromosomal evolution in this group. An investigation of five of the species studied showed some similarities such as a sex chromosome system of "parachute type" (Xy_p), the presence of 10 autosomal bivalents (2n = 22) and heterochromatin localized around centromeres. These observations are similar to those already described for Otiorhynchini species, and confirm the karyological conservatism of this weevil group. In contrast, another species Cirrorhynchus kelecsenyi has an additional four autosomal bivalents (n% = 14 + Xy_p, 2n = 30), which differs considerably from the chromosomal homogeneity of the other genera. Karyotypic evolution in this species was achieved most probably by increasing the number of chromosomes by centric fissions, resulting in variation in the number of acrocentric chromosomes. DAPI-positive and CMA₃-negative reactions of heterochromatic DNA in all the species studied suggest that it has an AT-rich composition. Impregnating chromosomes with silver nitrate reveals NORs on one pair of autosomes, and probably argentophilic material in the interspace between the X and y sex chromosomes. The karyological findings support the taxonomical revision of Otiorhynchini based on morphological characters.

The cocoons characteristic of the prepupal and pupal stages of many insects vary widely in size, durability, structure, shape and colour, as well as in other features such as orientation and attachment to the substrate. In some species they vary seasonally. Most cocoons provide little direct insulation, although they may reduce the rate at which temperature changes, but many provide the mechanical protection required for overwintering beneath insulating substrates such as soil and snow. The cocoons of some terrestrial species prevent inoculative freezing by isolating the integument from ice crystals on the cocoon surface or its surroundings. In some aquatic species, cocoons appear to limit damage by providing mechanical protection during the freezing of surrounding water. Some cocoons help in the acquisition of solar heat: dark structures are especially effective because dark pigments absorb heat, and surrounding layers trap this heat. Insects are immobilized when it is cold and so cannot move in response to environmental threats, and protective cocoons made for winter tend to be more robust than their summer counterparts. Such cocoons protect against abrasion of the waterproof layer of the cuticle. In some species, robust cocoons or complex structures impede natural enemies. Cocoon silk has anti-bacterial and anti-fungal actions. Other cocoons are more or less waterproof. These and other features withstand simultaneous constraints in addition to cold. Therefore, cocoons enhance survival during cold conditions in many species. However, this conclusion is based on fragmentary evidence, and there has been relatively little explicit examination of the roles of cocoons during winter. Therefore, specific work is required to assess resistance to or enhancement of inoculative freezing, resistance to penetration by natural enemies and water, the roles of particular cocoon silks and silk constituents, and the quantitative contributions of cocoons to winter survival in nature.

After leaving their hosts, the larvae of endoparasitic braconid wasps pupate in cocoons. To determine their investment in cocoon silk, the dry weight of newly emerged wasps and that of the empty cocoons were measured for three gregarious braconid species of slightly different sizes: Glyptapanteles liparidis (Bouché), Cotesia glomerata (L.) and Cotesia kariyai (Watanabe) (Hymenoptera: Braconidae, Microgastrinae). These braconids form clusters of cocoons of different types. Glyptapanteles liparidis is significantly larger than either of the Cotesia species, and C. kariyai is the smallest. The ratio of the weight of cocoon silk to the total weight of cocoon silk, wasp body, cast cuticle and meconium is smaller for small species than large species. Small species economise on their use of silk by aggregating cocoons and can therefore invest a larger fraction of their resources in adult body mass. Moreover, the larvae of the smallest species, C. kariyai, additionally reduce their use of silk by constructing a communal airy silk layer beneath which the individual cocoons are formed.