We have investigated the relative importance of bark roughness and host tree species in determining the diversity and make-up of coleopteran assemblages on the trunks of trees in sub-tropical rainforest in south-east Queensland, Australia. There are clear, statistically significant, patterns in the composition of the assemblages which reflect bark roughness. Rougher bark had associated greater species and family richness, a higher proportion of "rare" species, a higher value for Shannon diversity and lower values for the Simpson and Berger-Parker Index (measures of dominance within the sample). The data support strongly the idea that there is a bark-specific beetle assemblage. The rougher bark was associated with significantly greater numbers of an anobiid species, Dorcatoma sp., and of the latridiid species Aridius australicus. Rougher bark also harboured significantly larger species. The most likely explanation for this seems to be related to the physical heterogeneity and biological complexity of the habitat, presenting, as it does, greater opportunities for shelter, feeding specialisation and intra-species aggregation. Rougher bark contained a higher proportion of both predatory and xylophagous groups than did smoother categories. No clear influence of tree species could be detected although some trends were evident.

The consumption and preferences of polyphagous ground beetles (Coleoptera: Carabidae) for the seeds of herbaceous plants was determined. The seeds were stuck into plasticine in small tin trays and exposed to beetle predation on surface of the ground. In the laboratory the effect of carabid (species, satiation) and seed (species, size) on the intensity of seed predation was investigated. The consumption of the generally preferred Cirsium arvense seed by 23 species of common carabids increased with body size. Seed of Capsella bursa-pastoris was preferred by small carabids and their consumption rates were not related to their size. The average daily consumption of all the carabid species tested (0.33 mg seeds . mg body mass^-1 . day^-1) was essentially the same for both kinds of seed. Because of satiation the consumption of seed of C. arvense provided ad libitum to Pseudoophonus rufipes decreased over a period of 9 days to 1/3-1/4 of the initial consumption rate. Preferences of P. rufipes (body mass 29.6 mg) and Harpalus affinis (13.4 mg) for the seeds of 64 species of herbaceous plants were determined. The small H. affinis preferred smaller seed than the large P. rufipes. Predation of seed present on the ground in the field was studied in 1999-2000, at Praha-Ruzyne (50°06´ N 14°16´E). Seeds were placed in stands of different crops as in the laboratory experiments and vertebrate predation was excluded by wire mesh cages. Pitfall traps placed near the cages revealed that carabids were the only seed predators active in the area. Rates of removal of seed of 6 weed species varied with crop, season, seed and site. Average rate of removal in June-August was 2.5 seeds.day^-1.tray^-1 and was smaller before and after this period. The rates of removal increased with increasing activity density of the carabids and paucity of seed from naturally occurring weeds, which may have satiated the carabids. In stands of winter wheat, millet and soybeans there were significant differences in the rates of removal of the seed of 43 herbaceous species. The field preferences were correlated with those established in the laboratory. Predation of seed on the ground in arable fields can be as high as 1000 seeds.m^-2.day^-1 and may selectively influence the quantity of seed of particular herb species that enters the soil seed bank. Seed predation thus may be an effective component of weed control on arable land, particularly at low weed densities.

A total of 23 uropodine species of the genus Trachytes (Acari, Mesostigmata) are reliably recorded to occur in Central Europe and included in identification keys for adults (23 spp.) and deutonymphal stages (9 spp.), respectively. For the first time, the diagnostic characters of deutonymphs of the species T. baloghi, T. minima, T. minimasimilis, T. mystacinus and T. splendida are figured. Ten species found in Slovakia are redescribed (T. aegrota, T. baloghi, T. hirschmanni, T. irenae, T. lamda, T. minima, T. minimasimilis, T. mystacinus, T. pauperior and T. splendida) and characterised by their external morphology, geographic distribution and ecological requirements in terms of habitat preference, affinity to merocoenoses and vertical distribution. The zoogeographic origin of Trachytes is analysed. Most species are found only in woodlands and have not been recorded in the distribution area of the Pannonian flora in Central Europe (except for T. aegrota and T. baloghi). Short taxonomic remarks are given for the species of dubious taxonomic status or whose occurrence is not reliably known.

Diapausing larvae of Aphidoletes aphidimyza (Diptera: Cecidomyiidae) had relatively low supercooling points (SCP) ranging from -19.0 to -26.4°C. None of the specimens that froze at this temperature survived. A high survival rate (up to 87%) at -10°C for 10 days was observed in supercooled larvae. Such features are characteristic for insects that use a chill-tolerance strategy of cold hardiness. However, the cocoons formed by the diapausing larvae were penetrable by external ice crystals and the larvae showed a relatively high survival rate (23 - 34%) at -10°C for 10 days also in the frozen state caused by inoculation by external ice at high subzero temperatures. Such a duality with respect to cold hardiness strategies seems to be ecologically relevant to overwintering in soil habitats where there may be unpredictable contact with external ice.

Labial gland secretions of 26 males of the bumblebee Bombus lucorum (L.), collected in the Czech Republic, were analysed. The secretions consisted of 60 compounds; ethyl (Z)-9-tetradecenoate was the main component (average 53%). Although the males varied in colour, their labial gland secretions were similar in composition, which indicated they belonged to one species. Chemically the B. lucorum occurring in the Czech Republic correspond to the earlier described "blonde form" of this species.

By means of a tracer assay using a labeled synthetic angiotensin converting enzyme (ACE) substrate hippurylglycylglycine, we have detected high ACE activity in the testes of the African migratory locust, Locusta migratoria. Lower, but significant, ACE activity was observed in midgut and hemolymph. In a two-step purification procedure involving anion exchange and gel permeation chromatography, we have purified LomACE from the locust testes. The enzyme of approximately 80 kDa shows substantial amino-acid sequence homology with ACE from both vertebrate and invertebrate origin. The ACE identity of the purified enzyme was further confirmed by cDNA cloning of the Locusta ACE fragment, which, after in silico translation, revealed a mature protein of 623 amino acids with a large structural similarity to other known ACE proteins.

The imagines, cast skin of the final larval instar, and venom apparatus of Chorebus pseudoasphodeli sp. n., an endoparasitoid of Phytomyza chaerophylli Kaltenbach, 1856 on Daucus carota L., and Chorebus pseudoasramenes sp. n., an endoparasitoid of Cerodontha phragmitophila Hering, 1935 on Arundo donax L., two new species of Dacnusini from Spain, are described, illustrated, and compared with those of allied species. The immature larvae, mature larva, and pupa of C. pseudoasphodeli sp. n. are also described, illustrated, and compared. Morphological structures of phylogenetic value are discussed, and keys for the discrimination of the imagines are provided.

The effects of body size on mating success and duration of copulation were investigated in Pyrrhocoris apterus. Under laboratory conditions relative mating success of small and large males was investigated in groups of 2 males (majority sex) : 1 female (minority sex). Large males were recorded significantly more often in copulation than small males when the female was large but not when the female was small. This was also the case when the group size was 24 males : 12 females or population density decreased by increasing the area of the experimental arena. In groups of 2females : 1 male, large females were recorded in copulation significantly more often than small females when the male was large but not when the male was small. Proportion of individuals of the minority sex that copulated was similar for males and females, regardless of body size. The average duration of copulation was similar for small and large males, but shorter for small than large females. The difference in the duration of copulation of small and large females was greater when it was with small rather than large males. The prolonged guarding of large females by small males may be explained by a trade-off between increasing the probability of inseminating an uneasily accessible high quality partner and copulating with more females.

The larvae of Netocia morio (Fabricius, 1781), Netocia oblonga (Gory & Percheron, 1833), Potosia opaca (Fabricius, 1787) and Potosia cuprea brancoi Baraud 1992 are described. Comparison of the morphology of both genera revealed important differences in raster structure, mandibles and frontal setae. The systematic position of both genera based on larval characteristics is discussed. Some aspects of larval biology are discussed.

Sexual dimorphisms in adult size (SSD) and development time (SDTD) occur in many groups of organisms. In insects, some of the best examples occur in parasitoid wasps where most studies report that females are larger than males but take longer to develop. Sex-specific differences in the effects of size on reproductive success is generally regarded as the main factor responsible for SSD in parasitoids. Most studies also assume that development time must be extended in order to achieve larger size. Here, SSD and SDTD were compared in the solitary endoparasitoid, Microplitis mediator that develops in larvae of the moth Pseudoplusia includens. The relationship between male and female body size and development time were isometric in M. mediator, but contradict most predictions of parasitoid development models. Across first to fourth instars at parasitism, male wasps were consistently larger than females but completed their development significantly faster. The longer development time in female wasps was due primarily to an extended pupal phase, whereas the duration of larval development did not vary significantly with offspring sex. Secondary sex ratios (percentage male) also did not vary with host instar. We conclude that SSD in M. mediator is not only a function of extended development time, but also because of several possible factors: (i) selection favours an increase in male size (relative to female size); (ii) female size is constrained because of predation risk, (iii) as a cost of reducing the cost of inbreeding or (iv) constraints on egg maturation rate. We argue that failure to look carefully at how parasitoids grow can lead to incorrect conclusions about the basis or significance of SSD.

Two new species of Enclisis Townes, 1970 from Spain are described and illustrated: E. dichroma sp.n. and E. schwarzi sp.n. The new species are distinguished from the closest species E. infernator and E. ornaticeps by head and leg characters and body colour. Data on their phenology and a key to these four European species are presented. External and internal scanning electron microscopy of male tyloids revealed that these structures, in both new species, have a secretory role.

A nonpigmenting strain of Serratia marcescens Bizio isolated from dead and apparently diseased wild apple maggot flies, Rhagoletis pomonella (Walsh), was shown to be pathogenic to healthy apple maggot flies upon ingestion. The microorganism was detected in live adult alimentary canal organs four days post ingestion but produced death in some flies within 24 h when flies fed on a cell concentration of 4.7 × 104 cfu/ml and within 8 h when flies fed on filter-sterilized culture medium that previously contained a 21 h culture of S. marcescens. Increasing the cell concentration 10,000 fold did not lead to an increased rate of kill. Young flies (7-10 days old) were more susceptible to infection leading to death than were older flies (21-28 days old). The potential use of S. marcescens cells as control agents against apple maggot flies is negated by their pathogenicity to vertebrates; however, the potential use of toxic compounds produced by this strain of S. marcescens is discussed.

The Dermaptera are a small order of insects, marked by reduced forewings, hindwings with a unique and complicated folding pattern, and by pincer-like cerci. Hindwing characters of 25 extant dermapteran species are documented. The highly derived hindwing venation and articulation is accurately homologized with the other pterygote orders for the first time. The hindwing base of Dermaptera contains phylogenetically informative characters. They are compared with their homologues in fossil dermapteran ancestors, and in Plecoptera, Orthoptera (Caelifera), Dictyoptera (Mantodea, Blattodea, Isoptera), Fulgoromorpha and Megaloptera. A fully homologized character matrix of the pterygote wing complex is offered for the first time. The wing venation of the Coleoptera is re-interpreted and slightly modified. The all-pterygote character analysis suggests the following relationships: Pterygota: Palaeoptera + Neoptera; Neoptera: [Pleconeoptera + Orthoneoptera] + [Blattoneoptera + (Hemineoptera + Endoneoptera)]. Blattoneoptera share at least 15 wing apomorphies with the sistergroup Hemineoptera + Endoneoptera and none with the Orthoneoptera and Pleconeoptera; Blattoneoptera: (Grylloblattodea + (Dermaptera + Dictyoptera)); Dictyoptera: (Mantodea + (Blattodea + Isoptera). Dermaptera share 13 wing apomorphies with the sistergroup Dictyoptera. In order to document the intra-ordinal relationships of Dermaptera, 18 new characters of venation and articulation are added to an existing data set and analyzed cladistically. The following relationships are suggested (43 characters, tree length 72, CI 0.819 and RI 0.935). Dermaptera: Karschiellidae + ("Diplatyidae" + ("Pygidicranidae" + (Allostethus indicum + (Anisolabididae + ("Labiduridae" + [Forficulidae + (Chelisochidae + Spongiphoridae)]))))). The taxa in quotation marks are probably paraphyletic. Fossil Dermaptera and "Protelytroptera" show that wing-folding characters were already present in Permian ancestors. The evolution of the dermapteran wing-folding mechanism is discussed and the hindwing is presented as a working "origami" model, which will fold as in living earwigs. The functional role of the wing base in wing folding is examined. Characters in orders and other higher taxa are not independent and cannot be analyzed out of context with their groundplans. Higher systematics is dealing with diametrally different problems than species-level systematics. The necessity of using a different methodology for species-level and higher-level phylogenetics is discussed and recommendations are made.

1. The Heteroptera, principally mirids, collected in a light-trap run on a field margin at Rothamsted Experimental Station for various periods between 1933 and 2000, have been identified, and the catches analysed to show the extent of change and stability in the community.
2. Trap catch, both in terms of individuals and species, was correlated with maximum daily temperature.
3. α-diversity showed a U-shaped curve over the period. The dip may have been associated with pesticide use, although a lack of days with high maximum temperatures cannot be ruled out.
4. By the late 1990s, α-diversity had again reached a peak (Fisher's = 11), comparable to that in the 1930s.
5. However, the change in the composition of the community over the whole period (β-diversity) was significant, the index of difference being 0.66 on a scale where 0 is no change in composition or relative abundance and 1 no species in common.
6. The value of β-diversity was highest in the water bugs, which disappeared altogether. Categorising the others by host plant type, the greatest change over time was in those associated with perennial herbs. There were decreasing differences in tree-dwellers and grassland species respectively, and the least change was in the community associated with annual plants (arable weeds).
7. Changes in the abundance of Heteroptera since 1933 follow closely those of the macrolepidoptera from the same samples. However changes in diversity show very different patterns, with moth diversity continuing to decline since 1960 in contrast to the increases apparent from the Heteroptera data.

The nymphs of spittlebugs (Hemiptera, Cercopidae) are xylem-feeders and live on herbs, grasses or woody plants within their self-produced spittle masses. Nymphs of the spittlebug Neophilaenus albipennis live aggregated in these spittle masses on their host plant Brachypodium pinnatum, a common grass in dry grassland. The objective of this study was to estimate nymphal mortality rates and to examine what role aggregation and vegetation structure play in the mortality of the nymphs. The aggregation and mortality were measured using two different methods, direct monitoring and caging of nymphs. The nymphs passively aggregated with up to 4 nymphs per spittle and aggregation decreased with instar. The aggregation of the nymphs resulted in a reduced mortality in all instars. Although it has already been argued that aggregation may be an advantage, this study is the first direct evidence (i.e. direct measurement of single individuals) for the benefit of aggregation to individual spittlebug nymphs. Despite a clumped distribution of N. albipennis nymphs in tall vegetation, nymphal mortality was not correlated with vegetation height.

The species of Testudobracon Quicke from eastern China are revised with four species recognized, including three new species: (Testudobracon flavus sp. n., Testudobracon guangxinensis sp. n. and Testudobracon grandiventris sp. n.). The new species are fully described and illustrated. A key to species of this genus is also provided. The types and other specimens are deposited in the Collection of Parasitic Hymenoptera at the Zhejiang University, Hangzhou, China.

Emergence of Coenagrion mercuriale and Ceriagrion tenellum was examined in a mixed population at their northern range margin in Britain. Mortality at emergence was quantified in C. mercuriale. Consistent with their larval diapause characteristics, both species had an asynchronous emergence pattern, typical of "summer" species. Daily emergence of C. mercuriale was positively correlated with the duration of sunlight on the previous day (controlling for season) and its emergence period was found to be shorter than that observed in its core populations in Central and Mediterranean Europe. No differences were found between the patterns of emergence of the sexes in either species. Sex ratio at emergence differed significantly from 1:1 (at 1.35 : 1 - males : females) in C. mercuriale but not in Ceriagrion tenellum (at 1.04 : 1). Body size at emergence declined more steeply with time in females than in males of C. mercuriale because large size may confer a greater reproductive advantage in females (larger females may be more fecund) than males in non-territorial odonates. Percentage mortality of C. mercuriale at emergence was low (4.9% including deformed individuals), the main cause of mortality being deformity.

In searching both for food to produce eggs and for suitable oviposition sites, females of aphidophagous ladybirds must be adapted to exploit prey that vary greatly in their occurrence and abundance over both space and time. A simple model of ladybird searching and oviposition behaviour emerged in the 1950s: adult ladybirds are highly mobile in traversing the landscape, but become less active and produce more eggs as their rate of aphid consumption increases. The net result is that most eggs tend to be laid at sites of high aphid density. Laboratory and field experiments and observations over the past several decades have generally supported this basic model, although the linkage between ladybird dispersal activity and local aphid density often appears to be relatively weak. Not all ladybird eggs are laid in patches of high aphid density. Females use resources from limited prey consumption to produce eggs in modest numbers. They may thus be prepared to lay some eggs quickly when they succeed in finding aphids in high numbers, but otherwise they may have little choice but to lay these eggs in suboptimal sites. Upon locating patches of high prey density, females are faced with the decision of how long to remain. The basic model raises the possibility that these females become passively trapped at such patches until local aphid density collapses. Recent studies, however, suggest that detection of oviposition-deterring pheromones may promote earlier departure from prey patches. Females may also have an innate tendency to disperse throughout their lives regardless of local conditions, as a bet-hedging strategy to spread their eggs widely over space. Additional studies are needed to evaluate further the degree to which females actively determine and vary the rhythms of dispersal and reproduction in response to the unpredictable and short-lived nature of populations of their aphid prey.

Genus-group taxa of Platerodinae are revised and valid taxa are redescribed. The validity of Plateros Bourgeois, 1879 is reinstated. Libnetomimus Kleine, 1927 is made a junior synonym of Libnetis Waterhouse, 1878. Calleros Gorham, 1881, Calloplateros Pic, 1923, Costatoplateros Pic, 1949, Ditoneces Waterhouse, 1879, Libnetomorphus Pic, 1921, Microplateros Pic, 1921, Planeteros Gorham, 1883, Tolianus Pic, 1921, Melampyrus Waterhouse, 1879, and the subgenus Cautirodes Pic, 1921 are considered to be junior synonyms of Plateros Bourgeois, 1879. The subgenus Pseudeuplectus Pic, 1922 is synonymized to Cavoplateros Pic, 1913, and Pseudoplateros Green, 1951 is made a junior synonym of Falsocalleros Pic, 1933. Macrolibnetis Pic, 1938 formerly classified with Platerodini is synonymized to Platerodrilus Pic, 1921. Samoaneros Blair, 1928 is considered to be a junior objective synonym of Melaneros Fairmaire, 1877, which is excluded from Platerodinae and is kept incertae sedis in Lycidae. Fernandum Pic, 1924 and Subdihammatus Kleine, 1926 are transferred to the subfamily Leptolycinae. Teroplas oculatus sp. n. and Microlycus mexicanus sp. n. are described. Neotype of Plateros brasiliensis (Lucas, 1857) and lectotype of Microlycus minutus Pic, 1922 are designated. In order to understand relationships within the subfamily, included genus-group taxa were cladistically analysed.

The unusual wing characters of the Permian insect Permostridulus brongniarti gen. n., sp. n. justifies the creation of a new family, the Permostridulidae fam. n., within the Panorthoptera. Phylogenetic relationships with the extinct order Caloneurodea, related to the Orthoptera (crickets, grasshoppers), are assumed. This assumption suggests an occurrence of the Permostridulidae at least since the Upper Carboniferous. The most prominent feature of the wing venation is a stridulatory apparatus, nonhomologous with those previously known in "panorthopterid" lineages. This is the oldest recorded sound-producing device of an animal.

The cabbage armyworm, Mamestra brassicae, enters diapause in the early pupal stage. Pupal diapause is induced by rearing the larvae under short day lengths. We previously demonstrated that feeding Dopa during last larval instar induces pupal diapause even under long day lengths. In order to elucidate the mechanism by which pupal diapause is induced after experiencing short day lengths or fed Dopa under long day lengths, we analyzed gene expression in the brain of M. brassicae larvae under both of these conditions using a subtractive hybridization technique. After the secondary screen, 49 clones and 28 clones were identified as short day length or Dopa-feeding specific clones, respectively. All of these genes were sequenced and, using the base sequences of these clones, primers were synthesized. To confirm the genes enhanced specifically by these conditions, quantitative real-time PCR was carried out. This quantitative PCR analysis identified 15 and 1 clone whose expression was enhanced by the short day length conditions or Dopa-feeding, respectively. Among these clones, the gene with a high level of identity to receptor for activated protein kinase C (RACK) from Heliothis virescens is the most dramatically up-regulated under both conditions.

A new diagnosis of Paronychiurus Bagnall, 1948 is given. P. ramosus (Folsom, 1917) and P. eous (Christiansen & Bellinger, 1980) comb. nov. are redescribed on the basis of the types and new specimens. Two new species are described: P. probus sp. n., P. hubbardi sp. n. A key to the species in this genus is presented.

The subfamily Metriorrhynchinae is the most species-rich clade of Lycidae (Coleoptera). A recent proposal suggests that the Erotinae is a sister group of the Metriorrhynchinae. Within the Metriorrhynchinae, evidence is presented for the monophyly of the Conderini and Metriorrhynchini and their sister group position. The Trichalina, Hemiconderina and Metriorrhynchina form the tribe Metriorrhynchini. The relationships between the basal lineages of this group are poorly understood. Several clades are distinguished within the Metriorrhynchina, but there is only weak evidence supporting a relationships between them. The distribution of individual clades is discussed. Carathrix Kleine, 1926 (= Pseudodontocerus Pic, 1921), Dilolycus Kleine, 1926 (= Metriorrhynchus Gemminger et Harold, 1869), Flabelloporrostoma Pic, 1923 (= Metriorrhynchus Gemminger et Harold, 1869), Rossioptera Kasantsev, 1988 (= Xylobanellus Kleine, 1930), Samanga Pic, 1921 (= Broxylus C.O. Waterhouse, 1879), Strophicus C. O. Waterhouse, 1879 (= Enylus C.O. Waterhouse, 1879), and Tapromenoeus Bocak et Bocakova, 1989 (= Prometanoeus Kleine, 1925) are proposed as junior synonyms. Pseudosynchonnus Pic, 1922 is transferred to the Erotinae (Taphini) and Pseudosynchonnus Pic, 1922, Protaphes Kleine, 1926, and Parapyropterus Kleine, 1926 are proposed to be junior subjective synonyms of Lycoprogenthes Pic, 1915. Redescriptions of Metriorrhynchinae genera and a key to genera are provided.

The influence of cucumber offered as a host plant either alone or with Aphis gossypii Glover (Hemiptera: Aphididae) was studied on the various life table and biological characteristics of the predatory bug Macrolophus pygmaeus Rambur (Hemiptera: Miridae). The nymphal development was studied at 15, 20, 25, 30 and 35°C while adult performance was assessed at 15, 20, 25 and 30°C, using a 16L : 8D photoperiod and 65 ± 5% r.h. Nymphs completed their development at all temperatures except at 35°C. Nymphal development took significantly longer time in the absence than in the presence of prey at 20 and 25°C, but the reverse was true at 15°C. Nymphal mortality was highest at 15°C in the presence of prey and it was mainly recorded at the first and second stages. Females oviposited a small number of eggs at all temperatures but not at 30°C in the absence of prey. The average number of eggs per female was almost similar with or without prey, being highest at 20°C, and adult longevity was highest at 15°C. The results concerning population parameters clearly showed that cucumber with or without prey can not support a population increase of M. pygmaeus. However, it seems that A. gossypii on cucumber inhibits development of M. pygmaeus more than when this aphid species is not present. This adverse effect on this host plant-prey system possibly results from the particular aphid genotype on cucumber, leading to high nymphal mortality, reduced fecundity and short adult life-span of M. pygmaeus.

The New World genus Ataeniopsis Petrovitz, 1973 is revised. Fifteen species are recognized including three new species: Ataeniopsis carupanoi sp. n. from Venezuela, A. jaltipani sp. n. from Mexico and A. vinacoensis sp. n. from Argentina. Lectotype of A. haroldi (Steinheil, 1872) is designated, the name of type species A. notabilis Petrovitz, 1973 is reestablished, five species are given in a new combination. The taxa are diagnosed, keyed and illustrated, and biological information and distribution data summarized following the species descriptions. A hypothetical phylogenetic analysis of Ataeniopsis based on cladistic analysis is presented.

Despite the impact of parasitoids on insect populations being extensively studied, indirect parasitoid-mediated effects remain rarely documented in natural communities. We examined the influence of shared parasitoids on the interactions between two functionally monophagous moths, Nonagria typhae and Archanara sparganii. The moths showed a considerable variation in terms of relative abundance and the degree of phenological synchrony between the species. On average, parasitism levels caused by shared parasitoids did not differ between the two host species. Relative parasitism levels of the two hosts, however, varied considerably among different samples. Percentage parasitism of the scarcer species, A. sparganii, thus could not be fully explained by that of the dominant species, N. typhae. The results indicated that A. sparganii may benefit from the presence of N. typhae. In particular, both low relative density as well as high phenological synchrony with N. typhae reduced parasitism levels in A. sparganii. The case thus indicates the presence of parasitoid-mediated indirect effects between the coexisting herbivores. The patterns of host use observed in this study are consistent with the scenario of frequency-dependent host use caused by changes in parasitoid behavior. Such a host use by parasitoids is suggested to promote numerical stability and coexistence of the moth species in the system studied.

Diapause intensity (DI) is a physiological trait represented by the duration of diapause under given conditions of environment. In many species, it is highly variable, probably being controlled by multiple genes and tends to form a cline in response to the latitudinal gradient of selection pressure. DI clines could be established artificially by crossing between lines of a cricket selected for different levels of DI, indicating the importance of genetic factors in the adaptive variation of DI. However, DI may be modified in response to seasonal cues both before and after the onset of diapause. Polymorphism in the intensity of prolonged diapause may split adults of a single population to emerge in different years. A unimodal distribution of DI may also result in polymodal termination of diapause, if DI variation is so large that chilling in one winter is not enough to terminate diapause for all members of a population. Bimodal termination of diapause after overwintering suggests heterogeneity in the final phase of diapause that requires high temperatures in spring. Polymodal termination of diapause subserves a bet-hedging strategy. Variability in DI thus provides insects with an important means of adaptation to their environments changing in space and time.

Many stress-induced genes, including those related to the insect humoral immune response, are upregulated during diapause even in the absence of stress. We further test the relationship between stress genes and diapause in Sarcophaga crassipalpis by cloning sarcotoxin II, a member of the attacin family, and examining its expression pattern in relation to pupal diapause. Unlike several other stress-related genes, sarcotoxin II is not developmentally upregulated during diapause, but it remains fully responsive to immune challenge. Interestingly, the elevation of sarcotoxin II mRNA in response to body wall injury, but not immune challenge, is initiated more slowly and persists longer in diapausing pupae than in nondiapausing individuals.

Exorista sorbillans, the uzi fly, is a serious tachinid pest of silkworm and is present in all silk producing areas of Asia. Assuming that E.sorbillans was accidentally transported from West Bengal to southern states of India, its population genetic structure was studied using 13 ISSR, 3 RAPD, two sets of universal primers and two sets of primers designed from a lepidopteran repeat sequence. Statistical analyses of DNA markers revealed significant genetic variability between the E. sorbillans populations from 4 different geographic locations (within 400 km of one another) in the southern states and the one from West Bengal (Murshidabad). Multivariate and discriminant function analyses indicate that the E. sorbillans from south India has diverged from the original gene pool of West Bengal and is suitable for studying the microevolution of adaptation to the conditions prevailing in the different cocoon producing areas in India.
Abbreviations used. GP = geographic population; ISSR = Inter Simple Sequence Repeat; PCR = Polymerase Chain Reaction; RAPD = Random Amplified Polymorphic DNA; SPSS = Statistical Package for Social Sciences; UBC = University of British Columbia; UNIV = Universal.

Spring wheat plants were grown in pots at three CO₂ concentrations (350, 550 and 700 ppm) and three soil water levels (40, 60 and 80% of field water capacity) in field open top chambers and were infested with bird cherry-oat aphids (Rhopalosiphum padi Linnaeus). Aphid population dynamics were recorded throughout the growing season and analysis of the chemical composition of spring wheat leaves was conducted at the same time. Results showed that: (1) Aphid populations increased with raised atmospheric CO₂ concentrations. (2) The aphid populations showed different responses to different CO₂ concentrations. The population size, population growth rate and population density found under the 350 ppm CO₂ treatment was far less than those recorded under the 550 and 700 ppm CO₂ treatments. The population size, population growth rate and population density recorded under the 700 ppm CO₂ treatment was slightly higher than those recorded under the 550 ppm CO₂ treatment. (3) The effect of CO₂ concentration on the aphid population was correlated with soil water level. The highest aphid population size was achieved under the 60% soil water treatment. (4) Atmospheric CO₂ and soil moisture had significant effects on the chemical composition of the wheat leaves. (5) Aphid population size correlated positively with the concentration of leaf water content, soluble proteins, soluble carbohydrates and starch, while correlating negatively with the concentration of DIMBOA and tannin.