The efficacy of pyriproxyfen, a juvenile hormone analog (JHA), was evaluated using third instar larvae of Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae). Various doses of the compound, ranging from 0.01 to 2 ng/larva, were applied topically to larvae (12 h before pupariation). Treatment did not prevent pupariation but inhibited adult emergence at all the doses tested. In a second series of experiments the ecdysteroid content of pupae was determined following application of pyriproxyfen at two doses, 0.108 and 0.29 ng/larva, corresponding to ID₂₅ and ID₅₀, the doses required for 25 and 50% inhibition of adult emergence, respectively. Pyriproxyfen treatment increased the duration of pupal development. In addition, enzyme immunoassay measurements of ecdysteroids in whole body extracts of pupae indicated that pyriproxyfen decreased the ecdysteroid content in a dose-dependent manner. Finally, the effects on the cuticle of pyriproxyfen (ID₅₀) were studied histologically, which revealed that this compound increased the thickness of the new adult cuticle and suppressed the formation of bristles. Biochemical analyzes revealed that an increase in chitin content of the cuticle is only recorded at the highest dose. Thus, a topical application of pyriproxyfen to third instar larvae interfered with the molting hormone and disrupted the normal development of this insect.

The ability of biocontrol agents to overcome the immune defense of pests is a crucial issue. This is the first study of lysozyme activity as an inducible humoral component of the defense of Schistocerca gregaria, which depends on the recognition of the elicitor molecules of pathogens and not on epidermal wounding or a spiking effect. The level of lysozyme activity in fat body, haemocytes and haemolymph plasma of naïve and immunologically challenged 5^th instar S. gregaria was evaluated using the zone of inhibition test against Micrococcus lysodeikticus. Various Gram-positive and Gram-negative bacteria as well as peptidoglycans (PGN) and lipopolysacchrides (LPS) of bacterial cell walls induce and increase in the level of lysozyme activity. Escherichia coli induced an increase in the level of activity of lysozyme in the fat body, haemocytes and plasma, but not in mid gut epithelium, 6-12 h after an immunological challenge and then it decreased to the constitutive level after 72 h. This study revealed that in S. gregaria there is a constitutive and a bacteria-inducible level of lysozyme activity, which protects it against infection by both Gram-negative and Gram-positive bacteria.

Sex ratio and chromosomes studies were performed on six of the seven species of genus Cyclocephala present in the Lesser Antilles. Most sex ratios based on light trapping are skewed, with a frequent, but not exclusive, strong excess of females. These unbalances vary from species to species and island to island for the same species. Comparing old (seventies) and recent captures, the imbalances seem to increase with time. All of the 72 karyotyped males were diploid: 20,XY. Of the 15 females studied, one (C. dominicensis) was triploid: 30,XXX, a condition that only occurs in parthenogenetic species of beetles. We conclude that parthenogenesis is progressively developing within different sexual populations of Cyclocephala in the Lesser Antilles, which accounts for the excess of females recorded there. We propose that preexisting recessive mutations are the cause and that island colonization, by preventing panmictic reproduction, favours the expression of these recessive mutations. This would account for the accelerated occurrence of new characters (speciation /sub-speciation process), including unusual modes of reproduction such as parthenogenesis, and that several genetically related populations express these characters independently on different islands.

Heteroptera caught during day and night sampling at a height of 200 m above ground at Cardington, Bedfordshire, UK, during eight summers (1999, 2000, and 2002-2007) were compared to high-altitude catches made over the UK and North Sea from the 1930s to the 1950s. The height of these captures indicates that individuals were engaged in windborne migration over distances of at least several kilometres and probably tens of kilometres. This conclusion is generally supported by what is known of the species' ecologies, which reflect the view that the level of dispersiveness is associated with the exploitation of temporary habitats or resources. The seasonal timing of the heteropteran migrations is interpreted in terms of the breeding/overwintering cycles of the species concerned.

This study was on the effect of three species of aphids (Aphis fabae, Macrosiphoniella sanborni, Brevicoryne brassicae) on the survival, growth and development of the immature stages of the aphidophagous coccinellids Coccinella septempunctata, Ceratomegilla undecimnotata, Propylea quatuordecimpunctata and Oenopia conglobata. The percentage survival was lowest, immature development most prolonged and the adults the lightest when these predators were fed on B. brassicae. In addition, C. septempunctata and C. undecimnotata performed better when fed on M. sanborni (74.1 and 72.0% total immature survival, respectively) than P. quatuordecimpunctata and O. conglobata (25.0 and 13.8% total immature survival, respectively). In addition, the host plant of A. fabae also had a significant effect on the performance of the predators. These coccinellids survived best, had shorter developmental times and were heavier as adults when fed on A. fabae reared on Vicia faba than on Phaseolus vulgaris. These results may be useful for improving the effectiveness of biological control practice and the production of coccinellids in an insectary.

Osmia rufa L. (Osmia bicornis L.) is a species of a solitary bee, which pollinates many wild and cultivated plants. A total of 900 cocoons containing mature individuals of Osmia rufa L. (450 females and 450 males of a known weight), were placed in each of four habitats (orchard, mixed forest, hay meadow and arboretum of the Dendrology Institute of the Polish Academy of Sciences at Kórnik). These bees were provided with artificial nests made of the stems of common reed. The following parameters were calculated: reproduction dynamics, total number of chambers built by females, mean number of breeding chambers per reed tube and mean number of cocoons per tube. Included in the analysis were also the nectar flowers and weather conditions recorded in each of the habitats studied. General linear mixed models indicated that the highest number of chambers was recorded in the hay meadow (6.6 per tube). However, the number of cocoons per tube was similar in the hay meadow, forest and orchard (4.5-4.8 per tube) but was significantly lower in the arboretum (3.0 cocoons per tube on average). Also, the highest reproduction coefficient, 317.5%, was recorded in the hay meadows. Some nests were also parasitized and the highest mean number of infected chambers per tube (0.68) was recorded in the forest. The number of chambers was positively related to temperature. These results indicate that habitat had a significant effect on the reproduction of the red mason bee.

In insects, the crustacean cardioactive peptide (CCAP) is involved mainly in the regulation of ecdysis and is both a hormone secreted into the haemolymph and a neuromodulator or neurotransmitter in the nervous system. However, this peptide has only been recorded in the brains of a few species of insects. The present study examined the distribution of CCAP in the cephalic ganglia of the cockroach, Periplaneta americana, using two kinds of specific antibodies. The antibody directed against synthetic CCAP detected a large number of CCAP-immunoreactive neurons in the protocerebrum, deutocerebrum, tritocerebrum, suboesophageal ganglion, optic lobes, frontal ganglion and neurohemal organs, while the antibody directed against CCAP precursor (pre-propeptide) stained only a few neurons within the central brain and frontal ganglion. The latter antibody also revealed similar sets of neurons in another species of cockroach, Gromphadorhina portentosa, and identified the CCAP precursor of approximately 15 kDa in size in Western blot analyses.

Recently, Imafuku & Kitamura (Eur. J. Entomol. 112, 2015: 328-333) succeeded in inducing males of two territorial butterflies, Chrysozephyrus smaragdinus and Neozephyrus japonicus, to respond to wing models by rotating the models. Based on the results of two-choice tests in which males stayed longer within 50 mm of the female model than the male model the authors claim that males of both of these butterflies identify females using the patterns on the wings. I think this study provides a new method for studying the discriminative abilities of butterflies. In contrast to static models, however, butterflies attracted to rotating models do not land on the models but remain at some distance from the moving models. A close approach to a model, therefore, does not always reflect the animal's preference. I suggest a better way of using this method for testing the discriminative ability of butterflies.

The arboricolous dolichoderine ant Liometopum microcephalum (Panzer, 1798) is considered to be mainly predatory, although there are some reports of it tending aphids. The main objective of the present study was to confirm that this ant has a trophobiotic relationship with aphids and assess seasonal differences in its utilization of honeydew. We hypothesized that the worker ants on trees where they have their nest (nest tree) and trees where they are foraging (foraging trees) should differ in gaster mass and sugar content depending on their direction of movement, and that both should be highest in spring. From spring to summer 2009, ascending and descending workers were collected from nest and foraging trees at a locality in South Moravia, Czech Republic. Mass of their gasters and their content of total and reducing sugars were measured using chemical (photometric) methods. Differences in gaster mass confirmed the flow of liquid food from foraging to nest trees, but there were no significant between-month differences. Contents of total and reducing sugars were positively correlated with gaster mass. The gasters of workers descending from foraging trees contained significantly more reducing sugars than those of workers descending or ascending nest trees. The content of reducing sugars was lowest at the beginning of the ants' activity period in April and highest in June, with a non-significant drop in July. Results for total sugars were similar, with the decrease in July being significant. The concentration of sugars in the gasters of workers ascending and descending nest trees did not differ significantly but the absolute content of total sugars was higher in the gasters of ascending ants. Results from foraging trees confirmed that the ants collected the honeydew from these trees. Possible reasons for the ambigous results for nest trees are discussed. We conclude that trophobiosis is an important component of the nutritional biology of L. microcephalum.

Many butterfly target species are associated with early successional stages of grasslands. The Blue-spot Hairstreak, Satyrium spini (Denis & Schiffermüller, 1775), is a target species of grasslands. However, it feeds on Common Buckthorn (Rhamnus cathartica), which is associated with late successional stages of grasslands. If S. spini would also be restricted to late seral stages, there might be a management dilemma due to the contrasting requirements of S. spini and other target species. The aim of this study was to determine the oviposition preference of S. spini in calcareous grasslands, and to give management recommendations to promote this species. Therefore, we studied the oviposition microhabitats of S. spini at three representative patches of the Diemel Valley (Central Germany) by comparing environmental conditions on occupied and control host plants. In total we surveyed 1,889 host plants. Altogether we found 148 batches of S.spini on them containing 396 eggs. Most of the eggs were on plants that grew under the warmest conditions. Females preferred to lay eggs on small (< 1.3 m) shrubs of Rh. cathartica fully exposed to the sun growing on steep south- and west-facing slopes. This butterfly showed no difference in its preference for bushes growing in hedges or solitarily. About 80% of the batches of eggs were laid on the upper surface of a twig fork close to the surface of the ground (< 1 m). Our study showed that S. spini is a species characteristic of mid-successional stages of calcareous grasslands. The survival of suitable habitats for S. spini depends on regular management. To achieve this we recommend traditional rough grazing with sheep and goats, which creates open grasslands with small Rhamnus plants. In addition, the shrubs in tall hedges bordering calcareous grasslands should be subjected to cutting on a rotating basis.

Insects feeding on the foliage of oak were studied on a mountain where species of Mediterranean deciduous and evergreen oak coexist. There were 58 insect species (54 Lepidoptera, 1 Coleopteran and 3 Hymenoptera) belonging to twenty families in the assemblage feeding on eight species of Quercus, two of which are introduced from nearby regions. The overlap in occurrence in time and of feeding niches of the insects feeding on the foliage of the different species of oak was determined using the: (a) Poole-Rathcke method, which tests phenological overlap and (b) Petraitis method, which tests niche overlap. This indicated that insect families partition seasonal time in a random and the entire assemblage in a regular way. All groups of insects partitioned season randomly except for the pairs of monophagous-oligophagous and Palearctic-Eurosiberian species, which partition season regularly. Oak folivorous insects correctly perceive the three subgenera of oaks with the exception of the planted Q. robur pedunculiflora. The folivorous insects recorded on the Mediterranean evergreen oaks (subgenus Sclerophyllodrys) differ from those on the other two subgenera (Quercus and Cerris) and co-occurring deciduous trees. The hypothesis of complete general overlap is rejected for groups based on feeding specialization, zoogeographical categories and taxonomic families. The same was the case when the entire insect assemblage was considered. The percentage of specific niche overlap of the folivorous insects is low and greatest among the monophagous species (13.8%) and those with a Mediterranean distribution (15.4%). Voltinism is not very important for this assemblage and only seven species are bivoltine of which four fed on a different species of oak in the second generation. The overall conclusion is that the co-occurrence in space of these species is possible because they occur regularly at different times during the season whereas that of insect groups based on zoogeographical, taxonomic or feeding specialization are randomly dispersed in time.

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.

We studied the diet of 10 species of grasshopper belonging to the family Pamphagidae over a period of 3 years at 6 localities in North Eastern Algeria. The species of plants consumed by the grasshoppers was determined by comparing slide mounted specimens of the pieces of plant epidermis in their faeces with those in a reference collection of identified plants collected from the same localities. The percentages of occurrence of the different species of plants in the faeces of the grasshoppers were not related to the abundance of the plants at the sites studied. All the grasshoppers were polyphagous but differed in the percentage of Poaceae in their diets. The diet of Tmethis and Ocneridia contained a higher percentage of Poaceae than the other species and are considered to be ambivores. The three species in the Pamphagus gr. djelfensis complex differ in their diets but all tend to avoid consuming Poaceae and are categorized as forbivores. We also compared the frequency of occurrence of Fabaceae in the faeces and in the field and O. volxemii is the only species that avoided consuming this plant family. The number of sensilla on the labrum was also studied in both sexes of each species. Once one corrects for differences in the size of the labrum, the forbivores have higher numbers of sensilla in groups A1, A2 and A3 (but not A10) than the ambivores. The numbers of sensilla in the A10 group on the labrum of species of Pamphagidae is greater than on that of species of Acrididae, which are mainly graminivores and adapted to semi-arid conditions.

The knowledge of the family Nicoletiidae in the Canary Islands was limited to two reports of Proatelurina pseudolepisma (Grassi, 1887), a species which belongs to the subfamily Atelurinae. This study provides new data on the occurrence of representatives of Nicoletiidae on these islands and descriptions of two endemic troglobic taxa: Canariletia holosterna gen. n. et sp. n., from the island of Gran Canaria, and Coletinia majorensis sp. n., found in Fuerteventura. The latter belongs to a group of species whose males have asymmetric antennae, so it is compared with those Coletinia of this group. Canariletia gen. n. shows a unique combination of characters inside Nicoletiidae, so its position within this family is discussed, considering the new genus as incertae sedis, but probably related to the Palaearctic and Afrotropical genera included in the subfamily Coletiniinae sensu Mendes, 1988.

Many species of lady beetles are highly promiscuous and females mate repeatedly even when not sperm-limited. We quantified female reproductive success and progeny development in Hippodamia convergens using a laboratory experiment designed to test whether (1) male novelty (different males), (2) male mating status (virgin, non-virgin) or (3) opportunities for female mate choice, would increase female fitness compared to a similar number of matings with the same male. Daily access to novel males, regardless of their mating status, increased the egg fertility of females, but not their fecundity. Opportunities for mate choice did not improve any measure of female reproductive success compared to arbitrary assignment of males, but slightly increased reproductive rate, as measured by the number of days to produce 15 clutches. The eggs of monogamous females had the fastest eclosion times, but larval development was fastest for progeny of females polyandrous with non-virgin males, and total developmental time did not differ among treatments. In a second experiment, confinement with two males during oviposition disrupted egg clustering and reduced egg fertility, but not female fecundity, relative to confinement with one male or oviposition in solitude, suggesting a negative impact of male harassment on female fitness in the presence of multiple males. However, the continued presence of two males also improved progeny survival and reduced progeny development time relative to female confinement with one, likely due to summation of paternal effects when females were allowed unlimited matings with both males. These results do not rule out genetic benefits of polyandry, but support the view that enhanced egg fertility is a primary benefit, and suggest more subtle benefits may be obtained in the form of additive paternal effects. The average number of female matings in nature may even exceed that required to obtain such benefits if females use "convenience polyandry" to diminish male harassment.

Prey preferences and feeding-related behaviour of a Central European species of Scydmaeninae, Euconnus pubicollis, were studied under laboratory conditions. Results of prey choice experiments involving 50 species of mites belonging to 24 families of Oribatida and one family of Uropodina demonstrated that beetles feed mostly on ptyctimous Phthiracaridae (over 90% of prey) and only occasionally on Achipteriidae, Chamobatidae, Steganacaridae, Oribatellidae, Ceratozetidae, Euphthiracaridae and Galumnidae. The average number of mites consumed per beetle per day was 0.27 ± 0.07, and the entire feeding process took 2.15-33.7 h and showed a clear linear relationship with prey body length. Observations revealed a previously unknown mechanism for capturing prey in Scydmaeninae in which a droplet of liquid that exudes from the mouth onto the dorsal surface of the predator's mouthparts adheres to the mite's cuticle. Morphological adaptations associated with this strategy include the flattened distal parts of the maxillae, whereas the mandibles play a minor role in capturing prey. Mechanisms for overcoming the prey's defences depended on the body form of the mite. When attacking oribatids that adopt the ptychoid defence (encapsulation) Euconnus opened the prodorsum and pressed the anal and genital plates deeply into the idiosoma, whereas it fed on all other mites by entering their bodies through small gnathosomal or/and genital openings, after breaking off mouthparts or/and genital plates. The preferential feeding of a specialized and locally abundant ant-like stone beetle on one family of Oribatida, documented here for the first time, has implications for the population dynamics of the prey and raises questions about predator-prey co-evolution and costs of an unusually prolonged period spent feeding when at risk from competition and attack by larger predators, typical of the habitats where Scydmaeninae occur.

To understand the factors governing the diversity, abundance and host associations of parasitoids attacking frugivorous drosophilid flies on Iriomote-jima, a subtropical island of Japan, we monitored parasitism on several occasions over the period 2003-2009. Fifteen drosophilid and 12 parasitoid species were recorded. Three species of Drosophila, D. bipectinata, D. albomicans and D. takahashii, bred abundantly in banana baits, though their abundance varied between years and seasons. Frequent parasitoid species were Asobara japonica, A. pleuralis (Braconidae), Leptopilina ryukyuensis and L. pacifica (Figitidae). L. victoriae was recorded only in December 2003. In addition, host acceptance and host suitability of the four most frequently recorded parasitoid species were studied in the laboratory. Most parasitoid and drosophilid species showed species-specific associations with more than one antagonist species, suggesting that they have been subjected to complex coevolutionary interactions. In addition, host range of most of the parasitoid species included one of the three major Drosophila species, suggesting that the abundance of potential hosts is one of the factors determining the evolution of parasitoid host use.

Establishing continuous and reliable colonies of pest-parasitoid systems in the laboratory is an essential requirement for carrying out manipulative experiments on biological control. Here we describe in detail the rearing protocols that we optimized for the efficient rearing of the cabbage moth Mamestra brassicae and its key parasitoid Microplitis mediator.

The giant, polytene chromosomes of Simulium carthusiense Grenier & Dorier, 1959 were mapped, and all rearrangements were resolved relative to the standard banding sequence for the S. vernum group. The species is chromosomally cohesive from Austria to Spain, and is characterized by a chromocenter, two unique fixed inversions, 10 unique autosomal polymorphisms, and undifferentiated sex chromosomes. Rare individuals (3%) have two types of supernumerary chromosomes, representing the third example of a simuliid species that carries two different supernumeraries in the same individuals. Band-sequence comparisons with chromosomal outgroups indicate that S. carthusiense is the sister species of a clade that includes S. beltukovae (Rubtsov, 1956), the S. cryophilum complex, and S. urbanum Davies, 1966.

Each year huge numbers of adults of Coccinella septempunctata occupy aestivo-hibernation sites on Uludaz Hill, Çimen Mountain in the Kahramanmaraş Province of Turkey. In 2008 and 2009 we investigated the phenology, population dynamics, mortality and natural enemies of C. septempunctata arriving on Uludaz Hill. Samples were collected once a month during the snow-free season (April-November) from the top of the hill (2273 m a.s.l.) and at two lower altitudes (1900 m a.s.l. and 2050 m a.s.l.) on the slopes of the hill. In both years C. septempunctata was clearly more abundant at the top of the hill than at the two lower altitudes, which is in accordance with the hypothesis that beetles migrating to dormancy sites are strongly attracted to sites at the highest altitudes. Numbers of C. septempunctata on the hill were low in April and May. The large increase in abundance recorded in June may be attributed to the arrival of a new generation from lowland breeding sites. Emergence of previous year colonizers from their winter shelters is less probable due to the high fat content of the beetles collected in June. Spring dispersal from the hill to lowland areas was not observed. We suppose that this dispersal was either prevented by low temperature or considerably delayed and not synchronized with the period of ladybird breeding activity in the surrounding lowlands. In addition, the C. septempunctata aestivo-hibernating on Uludaz Hill suffered very high mortality, mainly caused by entomopathogenic fungi of the genus Beauveria. The results of our study are discussed in terms of the ecological trap concept.

Hydrophilus acuminatus larvae are known to feed on aquatic prey. However, there is no quantitative study of their feeding habits. In order to determine the feeding preferences and essential prey of larvae of H. acuminatus, both field and laboratory experiments were carried out. Among the five potential species of prey, Austropeplea ollula (Mollusca: Lymnaeidae), Physa acuta (Mollusca: Physidae), Asellus hilgendorfi (Crustacea: Asellidae), Palaemon paucidens (Crustacea: Palaemonidae) and larvae of Propsilocerus akamusi (Insecta: Chironomidae), the first instar larvae of H. acuminatus strongly prefered the Austropeplea and Physa snails in both cafeteria and single-prey species experiments. Larvae that were provided with only snails also successfully developed into second instar larvae, while larvae fed Palaemon, Propsilocerus larvae or Asellus died during the first instar. In addition, the size of adult H. acuminatus reared from first-instar larvae and fed only snails during their entire development was not different from that of adult H. acuminatus collected in the field. This indicates that even though the larvae of H. acuminatus can feed on several kinds of invertebrates, they strongly prefer snails and without them cannot complete their development.

Encarsia sophia (Girault & Dodd) (Hymenoptera: Aphelinidae) is an important bio-control agent of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Storage at low temperature is a valuable method used in the mass rearing of biological control agents to ensure the availability of sufficient parasitoids when needed. However, storing parasitoids at a low temperature may lead to a decrease in their fitness. The aim of this study was to determine the effect of different durations of constant low temperature storage on the fitness traits of the above parasitoid. The effect of storage at three temperatures (4, 8 and 12 ± 1°C, RH = 65-75% and in darkness) for periods of 1, 2 or 3 weeks and at two pupal stages (10 and 12 days old) was studied. The percentage emergence, time to emergence, longevity, size and ability of the females that emerged to parasitize B. tabaci were evaluated. The results indicate that there is a decrease in percentage emergence, longevity and ability to parasitize the longer and lower the temperature at which the pupae of E. sophia are stored. The percentage emergence of both pupal stages kept at 12°C for a week was not affected. However, at lower temperatures (8 and 4°C) percentage emergence after storage of two weeks decreased to 67-87.5% and after three weeks none emerged. The time to adult emergence was longer for 12 day old pupae at all temperatures and storage times. The longevity of the adults that emerged from both pupal stages after one week of storage at 12 and 8°C was not affected, but decreased to 66-72% with increase in storage time. There was no effect of cold storage on adult size when 10 day old pupae were stored. The ability of this parasitoid to parasitize B. tabaci after emerging from both pupal stages stored at all of the temperatures regardless of storage time was significantly lower. Effect of storage at 12°C for a week in terms of percentage emergence and longevity did not differ from that of the control, but nevertheless they were less able to parasitize B. tabaci. Although the information on the effect of cold storage on E. sophia is very limited, the results of this study indicate that for more efficient biological control there is an urgent need to improve the method of storing pupae.

This article is a comprehensive summary of the 50-year history of physiological investigations in the Czech Republic into the mode of action of the corpus allatum hormone (CAH) in insects, which is commonly known as the juvenile hormone (JH). During this period 4000 synthetic JH- mimetic bioanalogues were tested. The sesquiterpenoid epoxy-homofarnesoate (JH-I), which is generally thought to be the true JH of insects, is an excretory product of the male colleterial gland, not an insect hormone. There are two principal hormones produced by the insect neuroendocrine system: activation hormone (AH) produced by neurosecretory cells in the brain and JH secreted by the corpora allata. The prothoracic glands are a subordinated target of JH, not PTTH; they are not involved in the regulation of moulting in insects. The development of larval, pupal and adult structures depends primarily on inherited instructions encoded within the genome, not on high, medium or low concentrations of JH. At the level of epidermal cells, the responses to JH are always "all-or-none" with intermediate forms mosaic mixtures of cells of previous and future developmental stages.

The functional role and commercial importance of insect pigments have been studied for well over a century. They are classified into those synthesized by insects, which include anthraquinones, aphins, pterins, tetrapyrroles, ommochromes, melanins and papiliochromes, and those sequestered from their host plants, the antioxidative carotenoids and water-soluble flavonoids. They can also be categorized into those that are produced by cyclization of linear precursors, e.g. anthraquinones, aphins and tetrapyrroles and those derived from cyclic precursors such as pterins, ommochromes, melanins and anthocyanins. Anthraquinones and aphins are derived by cyclization of linear polyketides via successive condensation of simple carboxylic acid metabolites and occur in two major Superfamilies of Hemiptera, the Coccoidea and Aphidoidae, respectively. Ommochromes, tetrapyrroles and melanins are derived from different amino acid precursors, tryptophan, glycine and tyrosine, respectively. Apart from providing body colouration, ommochromes are visual pigments, melanins act as a protectant against UV and tetrapyrroles facilitate oxygen transport to cells. Papiliochromes are synthesized using both, the essential amino acids tyrosine and tryptophan. Pterins are derived from guanosine triphosphate (GTP) and are also present in ommatidia of eyes. The sequestered pigments, anthocyanins and carotenoids, are synthesized from phenylalanine and by condensation of two isoprene units, respectively, in plants. The biosyntheses of chemochromes in insects are governed by a complex set of enzymes, pathways and genetics. This review provides a comprehensive understanding of the molecules that are not only responsible for the striking colours but also provide functional benefits for insects. The commercially important pigments are also discussed.

The ecological and genetic mechanisms that determine Phasmatodea reproductive biology are poorly understood. The order includes standard sexual species, but also many others that display distinct types of parthenogenesis (tychoparthenogenesis, automixis, apomixis, etc.), or both systems facultatively. In a preliminary survey, we analysed Wolbachia and Spiroplasma infection in 244 individuals from 28 species and 24 genera of stick insects by bacterial 16S rRNA gene amplification. Our main aim was to determine whether some of the bacterial endosymbionts involved in distinct reproductive alterations in other arthropods, including parthenogenesis and male killing, are present in phasmids. We found no Wolbachia infection in any of the phasmid species analysed, but confirmed the presence of Spiroplasma in some sexual, mixed and asexual species. Phylogenetic analysis identified these bacterial strains as belonging to the Ixodetis clade. Other bacteria genera were also detected. The possible role of these bacteria in Phasmatodea biology is discussed.

Caddisflies are often used in studies on freshwater ecosystem ecology because of their aquatic-dependent larvae. The present study addresses the ecological affinities of larvae of Hydropsyche incognita in terms of the pattern of distribution of this species in the Romanian Carpathians using a boosted regression trees (BRT) model. A population cluster located in the western Romanian Carpathians was identified by the spatial analysis. The statistical model revealed that this species prefers a neutral to low-alkaline pH, high levels of dissolved oxygen, low conductivity, fast flowing water, moderate sized rivers at an altitude below 600 m a.s.l. and low concentrations of organic pollutants. An eastward decrease in the frequency of H. incognita populations was recorded along rivers in the Carpathians. The predictions derived from the BRT model on sites outside the population cluster suggest that many locations in the central and eastern Romanian Carpathians are suitable for H. incognita. However, this species was found at only a few of these locations. In contrast, some populations in this area were found in habitats predicted as unsuitable. There are several possible explanations of this, one of which is random dispersion of the species by flying adults.

The Asian chestnut gall wasp (ACGW), Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), is a global pest of chestnut trees. This pest was first recorded in Slovenia in 2005. Despite strict phytosanitary measures it was present throughout the country in native chestnut stands by 2013. We provide here the first overview of the parasitoids of ACGW in Slovenia recorded over a 4-year period and the direct interactions between parasitoid communities attacking hosts on chestnut and oaks at the same sites. A total of 27 species of native parasitoids that normally parasitize oak cynipids emerged from ACGW galls. The most abundant species were Torymus flavipes and Eupelmus urozonus. Seven species appear to be geographically well distributed in Slovenia. Twelve species of oak gall wasp were parasitized by 19 species of parasitoids. All native parasitoids have broad host ranges, so a large parasitoid diversity within this community can be expected. This is a novel study comparing the parasitoid communities associated with chestnut and oak galls.

Macrolophus pygmaeus Rambur (Hemiptera: Miridae) and Adalia bipunctata (L.) (Coleoptera: Coccinellidae) are two predatory insects commonly used as biological control agents. In order to determine the incidence with which both species attack and eat each other [Intraguild predation (IGP)], the direction and symmetry of the interaction between A. bipunctata and M. pygmaeus were characterized. In addition, whether the intensity of IGP between these two predators increased when the number of extraguild prey Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae) decreased, was also determined. Unidirectional sensu stricto IGP between A. bipunctata and M. pygmaeus was recorded: when IGP occurred, A. bipunctata was always the IG predator that killed and ate M. pygmaeus, the IG prey. However, the intensity of IGP was a function of the abundance of the extraguild prey, A. pisum, since IGP increased when the number of extraguild prey decreased. These results are discussed in terms of theoretical models that predict stability and the outcome of using natural enemies to control pests.

The present study provides new data on the morphology and distribution of the labial tip sensilla of 41 species of 20 gerromorphan (sub)families (Heteroptera: Gerromorpha) obtained using a scanning electron microscope. There are eleven morphologically distinct types of sensilla on the tip of the labium: four types of basiconic uniporous sensilla, two types of plate sensilla, one type of peg uniporous sensilla, peg-in-pit sensilla, dome-shaped sensilla, placoid multiporous sensilla and elongated placoid multiporous sub-apical sensilla. Based on their external structure, it is likely that these sensilla are thermo-hygrosensitive, chemosensitive and mechano-chemosensitive. There are three different designs of sensilla in the Gerromorpha: the basic design occurs in Mesoveliidae and Hebridae; the intermediate one is typical of Hydrometridae and Hermatobatidae, and the most specialized design in Macroveliidae, Veliidae and Gerridae. No new synapomorphies for Gerromorpha were identified in terms of the labial tip sensilla, multi-peg structures and shape of the labial tip, but eleven new diagnostic characters are recorded for clades currently recognized in this infraorder. One synapomorphy is recorded for Hydrometridae + Hermatobatidae + Macroveliidae + Veliidae + Gerridae; five for Macroveliidae + Veliidae + Gerridae; one for Veliidae + Gerridae; and one for Gerridae alone. Within Gerridae, one possible autapomorphy is recorded for Trepobatinae, and two possible autapomorphies for Rhagadotarsinae. We also record a possible autapomorphy for Cylindrostethinae, which indicates that this taxon is monophyletic, as is indicated by other morphological characters. Finally, we record one putative diagnostic character for Macroveliidae + Veliidae, two families that are otherwise not considered sister groups. This new set of characters based on features of the mouthparts of gerromorphan bugs might provide new insights into the cladogenesis of the infraorder.