The possibility of storing natural enemies at low temperatures is important for the mass production of biological control agents. We evaluated the effect of different periods of cold storage on immature mortality, mummy body mass, lifespan, reproduction and flight capacity of the parasitoid Praon volucre (Haliday). One-day-old mummies of the aphid Macrosiphum euphorbiae (Thomas) containing pre-pupae of P. volucre were stored in a climatic chamber at 5°C and 70 ± 10% RH in the dark for different periods of time (5, 10, 15 and 20 days). The control consisted of mummies kept at 22 ± 1°C, 70 ± 10% RH and a 12 h photophase. Percentage adult emergence, mummy body mass, flight capacity and number of eggs in the ovarioles of P. volucre females decreased with increase in the period of storage, while the longevity of females was only slightly affected. Fat content of mummies, percentage of parasitized aphids and survival of progeny to emergence decreased with increase in the period of storage. Storage of P. volucre pre-pupae for up to 5 days at 5°C did not affect any of the above mentioned parameters. The fact that P. volucre pre-pupae can be stored for 5 days without loss of quality and for 10 days with only a slight loss facilitates the planning of mass production and shipment.

Hydrocarbons play a major role in the life cycle of insects. Their composition and concentration can be affected by several factors. Hydrocarbons are biosynthesized in oenocytes and subsequently transported to the cuticle of insects, such as Drosophila suzukii (Matsumura) (Diptera: Drosophilidae). As the extraction procedure markedly affects the type and amount of hydrocarbon obtained we determined the association between the time taken to extract the maximum amounts of these compounds and the behaviour of D. suzukii. The required extraction time to reach a steady state is different for each hydrocarbon, which in most cases is more than one hour. On the other hand, if the entire hydrocarbon profile of D. suzukii needs to be investigated, extraction times significantly longer than one hour were required. By extending the extraction time 5 additional hydrocarbons were detected in D. suzukii for the first time. One of them, dodecane proved to be repulsive to D. suzukii. In addition, it took 3 h of extraction to determine the maximum value of 9-pentacosene, which is responsible for triggering mating behaviour in D. suzukii.

The development, reproduction and life table parameters of the predator Nephus arcuatus Kapur (Coleoptera: Coccinellidae), the most important predator of the spherical mealybug, Nipaecoccus viridis (Newstead) (Homoptera: Pseudococcidae) were studied at five constant temperatures (15, 20, 25, 30 and 35 ± 1°C, 65 ± 5% RH and a photoperiod of 14L : 10D). The duration of total pre-adult stage was found to decrease with increase in temperature from 60.0 days at 20°C to 15.3 days at 35°C. The oviposition period lasted 58.5, 44.7, 53.2 and 24.5 days at 20, 25, 30 and 35°C, respectively, with females laying an average of 164.8, 415.2, 660.4 and 136.6 eggs, respectively, at these four temperatures. Life table data were analyzed using an age-stage, two-sex life table. The intrinsic rate of increase (r_m = 0.1540 d^-1), finite rate of increase (λ = 1.1666 d^-1) and net reproductive rate (R₀ = 197.9 offspring) were greatest at 30°C. The shortest mean generation time (T = 30.6 days) was recorded at 35°C. These results indicate that N. arcuatus can successfully survive and reproduce at temperatures of around 30°C and has the potential to be an effective biological control agent of N. viridis and other mealybugs in warm regions.

Non-native species pose a threat to native organisms. When non-native and native species are closely related, the former can often competitively exclude the latter. Many studies have focused on competitive exclusion of native insect species by non-native eusocial hymenopterans, including ants, hornets, paper wasps and bees. Although solitary species of wasps have been introduced in many regions, few studies have investigated the effects of these insects on their native congeners. We investigated competitive interactions between native and non-native solitary wasps belonging to the same genus (Hymenoptera: Vespidae: Eumeninae: Anterhynchium). Specifically, we compared resource use and natural enemies of the native Anterhynchium flavomarginatum and supposedly non-native A. gibbifrons at a forest edge in Takasago, Hyogo, Japan, in June-October 2019, using trap nests (bamboo canes). Of 950 bamboo canes, 70 (7.4%) and 50 (5.3%) were used as nests by A. flavomarginatum and A. gibbifrons, respectively. Anterhynchium flavomarginatum produced two generations over the period studied, whereas A. gibbifrons produced only one. Although A. gibbifrons began nesting two weeks after A. flavomarginatum, the nesting period of A. gibbifrons overlapped that of the first nesting period of A. flavomarginatum. Nest architecture and the inner diameter of the canes used by both species were similar, suggesting potential competition for nesting resources. Anterhynchium flavomarginatum used larvae of 14 species of moths (Lepidoptera: Crambidae, Pyralidae, Tortricidae) as food for their larval offspring, whereas A. gibbifrons used only a single species, Demobotys pervulgalis (Lepidoptera: Crambidae). Prey species were exclusive to each wasp species, indicating no competition for this resource. Three parasitoid species, Macrosiagon nasutum (Coleoptera: Ripiphoridae), Amobia distorta (Diptera: Sarcophagidae) and Megaselia sp. (Diptera: Phoridae), attacked both Anterhynchium species. The percentage parasitism by Amobia distorta was higher for the native A. flavomarginatum. Anterhynchium gibbifrons may indirectly affect A. flavomarginatum via shared parasitoids.

Invasive mosquitoes are vectors of important human and animal pathogens and a serious threat to public health. Aedes albopictus (Skuse) (Diptera: Culicidae) and Culex quinquefasciatus (Say) (Diptera: Culicidae) are good examples because of their wide occurrence, host range and vector competence. An understanding of the responsiveness of mosquitoes to olfactory stimuli is essential for implementing effective surveillance and developing repellents. The present study evaluated the behavioural responses of A. albopictus and C. quinquefasciatus to CO₂ and human skin odour in an olfactometer. In addition, CO₂ synergistic effect was assessed in association with human skin odour. Mosquitoes of different ages (3-5 and 10-15 day old) were included in the study in order to determine changes in responsiveness to attractants during an insects' lifetime. The highest numbers of mosquitoes captured associated with CO₂ were (A. albopictus, 48/77, 62.34%; C. quinquefasciatus, 117/126, 92.86%) and hand odour (A. albopictus, 211/232, 90.95%; C. quinquefasciatus, 320/374, 85.56%) in the "CO₂ vs blank" and "hand vs blank" treatments. Skin odour was the most attractive for both species (A. albopictus, 279/309, 90.29%; C. quinquefasciatus, 292/306, 95.42%) in "CO₂ vs hand" experiment. The highest mosquito responsiveness was recorded in the "CO₂ + hand vs hand" bioassay (A. albopictus, 174/265, 65.66%; C. quinquefasciatus, 231/425, 54.35%). Similar trends were recorded for 10-15 and 3-5 day old mosquitoes of both species in all the experiments. In addition, a linear mixed model was used to evaluate the interactions between species, age and attractants. Human skin odour and CO₂ were effective attractants for both A. albopictus and C. quinquefasciatus (attractant-species interaction, p-value < 0.05). CO₂ synergistic effect was recorded for both species (species-attractant interaction, p-value < 0.05) even when CO₂ was not directly combined with skin odour (p-value < 0.05). The interaction between attractant and age revealed (p-value < 0.05) that in both species, 10-15 day old mosquitoes were more responsive to CO₂ and human skin odour, than younger (3-5 days) adults. The species-age interaction (p-value < 0.05) showed that 3-5 and 10-15 day old C. quinquefasciatus were more receptive to CO₂ and skin odour, especially when used in combination, than A. albopictus.

The present review discusses the molecular mechanisms of injury caused by low temperatures and/or freezing. The review is intended mainly for insect environmental physiologists who focus on the effects of low temperatures. The review successively discusses (1) the effects of low temperatures on the structure and function of macromolecules; (2) the effects of freezing on cells and macromolecules and (3) the mechanisms of damage during thawing and post-thaw. The review shows that injury primarily occurs at the molecular level in terms of damage to proteins, nucleic acids and biological membranes. The damage to macromolecular structures occurs as a result of the interaction between the effects of temperature, ice formation and resulting secondary effects such as osmotic stress, increased concentration of solutes, cellular freeze dehydration, disruption of ionic balance and oxidative stress. The present review attempts to identify gaps in our knowledge on the mechanisms of cold injury in organisms and proposes possible future directions that could contribute to filling the gaps.

In insects, the photoperiodic system comprises a linked sequence of events from photoreception to final seasonally-appropriate phenotypes such as overwintering diapause. The first and last of these events are reasonably well known, but central phenomena such as those distinguishing short from long days (time measurement) and the nature, accumulation and transfer of this information through development, metamorphosis and sometimes across generations remains obscure. Bünning's intuitive suggestion that photoperiodic time measurement was a function of the circadian system, made eight decades ago, however, has provided a framework for numerous studies investigating these connections. This review examines the development of Bünning's hypothesis from its origin in plants to the physiology of diapause in insects. Despite considerable inter-species differences, a close and probably causal relationship between circadian rhythmicity and photoperiodism is indicated.

The functions of the larval salivary glands (SGs) of Drosophila are traditionally associated with the production of a massive secretion during puparium formation; it is exocytosed into a centrally located lumen and subsequently expectorated via ducts, the pharynx and mouth. This so-called proteinaceous glue serves as an adhesive to attach the puparial case to a solid substrate. Great attention has been paid to the secretory cells of SGs, which are famous for their giant polytene chromosomes. However, substantially less attention has been devoted to individual or common ducts that form the most proximal portion of the SG organ via which the glue is released into the pharynx. In the present paper, we describe the organization and fine structure of the taenidia, highly specialized circumferential ring-like extracellular (cuticular) components on the internal side of these tubes. Two chitin-specific probes that have previously been used to recognize taenidia in Drosophila tracheae, Calcofluor White M2R (also known as Fluorescent Brightener 28) and the novel vital fluorescent dye SiR-COOH, show positively stained ductal taenidia in late larval SGs. As seen using scanning electron microscopy (SEM), the interior of the ductal tube contains regular and densely-arranged ridge-like circumferential rings which represent local thickenings of the cuticle in various geometries. The microtubular arrays that optically colocalize with taenidia in both the trachea and SG ducts are specifically and strongly recognized by fluorescently-conjugated colchicine as well as anti-tubulin antibody. In contrast to taenidia in the tracheae, the analogous structures in SG ducts cannot be detected by fluorescently-labeled phalloidin or even actin-GFP fusion protein, suggesting that the ducts lack a cortical network made of filamentous actin. We speculate that these taenidia may serve to reinforce the duct during the secretory processes that SGs undergo during late larval and late prepupal stages.

Seasonal and geographical adaptations in terms of obligatory embryonic diapause in the parthenogenetic stick insect, Ramulus mikado, were studied. First and second instar nymphs were collected at locations at three latitudes in Japan and reared in the laboratory under a photoperiod of 16L : 8D or 12L : 12D at 25°C. Their eggs were kept at 30°C for 30 or 60 days after oviposition, but no eggs hatched. Hatching was observed more than 100 days after transfer from 30°C to 15°C. The long period between transfer and hatching indicate that eggs in an early embryonic stage of development enter diapause at high-temperatures. The time from oviposition to hatching of eggs laid by adults that originated from the three locations kept under constant conditions between 15 and 25°C were compared. In all these experiments, eggs laid by individuals originating from high latitudes took longer to hatch. The eggs of those originating from Okayama and Ehime did not hatch at 25°C. However, more than 80% of the eggs of those that originated from the northernmost population hatched. Hatching before winter was observed when the eggs of those that originated from the northern population were placed outdoors in Okayama, even when the maternal insects were reared under long-day conditions in the laboratory. These findings indicate that univoltine R. mikado enters diapause twice during embryonic development, which enables it survive adverse conditions in summer and winter, respectively. Furthermore, diapause intensity was lowest in insects that originated from the lowest latitude.

The potato tuberworm, Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae), is a major pest of potato, Solanum tuberosum L. (Solanales: Solanaceae), both in the field and storehouses. The rate of development and survival of P. operculella, reared on potato tubers cv. Spunta at eight constant temperatures (17.5, 20, 22.5, 25, 27.5, 30, 32.5 and 35°C), were studied in the laboratory. The duration of development of the immature stages was recorded. Adult longevity was also recorded under the same conditions. Developmental time decreased significantly with increase in temperature within the range 17.5-32.5°C. No development occurred at 35°C. Survival (%) from egg to adult was higher at temperatures within the range 17.5-27.5°C than at either 30 or 32.5°C. Linear and a non-linear (Logan I) models were fitted to our data in order to describe the developmental rate of the immature stages of P. operculella as a function of temperature and estimate the thermal constant (K) and critical temperatures (i.e., lower developmental threshold, optimum temperature for development, upper developmental threshold). Lower developmental threshold and optimum temperature for development ranged between 12.5-16.2 and 31.7-33.8°C, respectively. The estimated upper developmental threshold for total immature development was 35.0°C. Thermal constant for total development was 294.0 degree-days. Adult longevity was significantly shorter at high (30 and 32.5°C) than at low temperatures (17.5-27.5°C). Our results not only provide a broader insight into the thermal biology of P. operculella, but also can be used as an important tool in planning an effective pest control program both in the field and storehouses.

Steroid hormone 20-hydroxyecdysone and the sesquiterpenoid juvenile hormone are the main regulators of insect development; however, it is unclear how they interact in the regulation of metamorphic events. Using the silkworm, Bombyx mori, we show that the juvenile hormone analogue fenoxycarb affects the cascade of ecdysone regulated genes that control the programmed cell death in the larval midgut. Morphological changes that occur during cell death were investigated by studying cross-sections of the midgut stained with hematoxylin and eosin. Apoptosis-specific DNA fragmentation was detected using TUNEL assay. Expression patterns of genes ATG8 and ATG12, which were used as indicators of autophagy, and genes of the ecdysone-regulated gene cascade were examined using real-time quantitative polymerase chain reaction. Fenoxycarb application on day 0 of the 5th larval instar extended the feeding period and postponed programmed cell death in mature larval midgut. This effect was probably due to a delay in ecdysone secretion and associated changes in gene expression were mostly not a direct response to the fenoxycarb. However, differences in the gene expression patterns in the control and fenoxycarb treated insects during the prepupal and early pupal stages indicated that fenoxycarb may also exert a more direct effect on some genes of the ecdysone regulated gene cascade.

The partial consumption of prey refers to when a predator does not consume all the digestible biomass of an animal it has killed. The frequency of partial consumption of prey by the polyphagous predator Macrolophus pygmaeus (Hemiptera: Miridae) was recorded for different species of prey and prey population structures, in single and mixed prey species patches. All the instars of the aphid, Aphis gossypii, were provided as prey alone or together with Myzus persicae or Macrosiphum euphorbiae. Numbers killed were determined when equal (10 nymphs of each instar, 40 in total) or unequal numbers (higher numbers of young nymphs but again 40 in total) of nymphs were placed on an eggplant leaf in a plastic Petri dish. In each dish a single 5^th instar nymph of the predator was introduced and the numbers killed and numbers of partially consumed aphids were recorded after 24h, at 25 ± 1°C. The numbers of A. gossypii killed were higher than those of the other species of prey used. The frequency of partially consumed prey was highest when A. gossypii was offered alone in equal numbers of each instar, followed by when A. gossypii was provided together with M. persicae in unequal numbers of instars (23.6% and 11.2%, of the total mortality, respectively). Killed but not consumed prey was also recorded, at frequencies that reached 10.7% of the total mortality when A. gossypii was provided alone in equal numbers of each instar. For M. persicae and M. euphorbiae, these percentages were significantly lower. The higher frequency of this behaviour when A. gossypii was the prey may be related to its lower nutritional quality for the predator. The effect of prey instar was not significant. These results indicate that in determining the numbers killed by a predator, partially consumed prey may make up a significant part of the total kill and thus should be taken into consideration.

Coordinated regulation of apoptosis is critical for development, homeostasis, and immunity in larvae of Metazoa. We determined the full nucleotide sequence of an inhibitor of an apoptosis protein in a lepidopteran insect Mythimna separata (Walker) (MsIAP) and carried out functional analyses of the MsIAP. The full-length cDNA of MsIAP was 1642 bp, which encoded 379 amino acid residues with a calculated molecular mass of 41,834 Da, and two BIR domains and one RING domain revealed using amino acid sequence analysis. In addition, the sequences of these domains were similar to Drosophila IAP1 and those of some other lepidopteran insects. We carried out a functional analyses of MsIAP related to apoptosis regulation using RNA interference. The effects of MsIAP knockdown on adhering hemocytes and non-adhering hemocytes as controls were examined using Hoechst33342/propidium iodide staining, effector caspase activity and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) staining. A significantly higher number of propidium iodide and TUNEL-positive cells was recorded in adhering hemocytes from MsIAP knockdown larvae than from control larvae, but these differences were not recorded for non-adhering hemocytes. However, higher effector caspase activity was detected in both adhering and non-adhering hemocytes from MsIAP knockdown larvae compared to that in control larvae. These results indicate that the knockdown of MsIAP induces apoptosis in larval adhering hemocytes, which MsIAP negatively and non-redundantly regulate apoptosis, and that IAP function is conserved in M. separata and other insect species including Drosophila and several lepidopteran insects.

The horse chestnut leaf miner Cameraria ohridella Deschka & Dimic (Lepidoptera: Gracillariidae) was first recorded in Europe near lake Ohrid in the former Yugoslav Republic of Macedonia in 1985 since when it has spread throughout the whole of Europe. The reasons for its spread are well documented. The aim of this study was to assess the population density of the first generation of C. ohridella at eight sites in the urban area of České Budějovice, Czech Republic in two consecutive years. The density was estimated visually in terms of the damage done to horse chestnut leaves by C. ohridella larvae at each site during the vegetative season. The results revealed high variability in the mean percentage of the leaf area damaged ranging from 1.43% to 31.00% and from 0.26% to 23.40% in 2012 and 2013, respectively. The effect of site, year and interaction between these two factors were statistically highly significant. Spatial analysis revealed no autocorrelation in damage among sites indicating that the distribution of C. ohridella is random and not affected by the level of infestation at neighbouring sites. In autumn, samples of leaves were collected and the mortality of diapausing pupae of C. ohridella determined. It ranged from 12.50% to 25.82% and from 10.31% to 22.35% in 2012 and 2013, respectively. There was no significant effect of site and year and their interaction on pupal mortality. The leaf samples were then weighed and put into photo-eclectors, which were placed outdoors. Numbers of adults of C. ohridella and hymenopteran parasitoids that emerged in spring were recorded daily. There were statistically significant associations of the total number of adults that emerged from samples in spring with both site and year as well as their interaction. The number of moths that emerged was positively correlated with the damage done by the first generation of C. ohridella the previous year. Similarly, the total number of parasitoids that emerged was correlated with the number of moths that emerged. The implications of these findings for the optimization of C. ohridella control are discussed.

The oriental fruit fly, Bactrocera dorsalis, is a key economic insect pest reducing fruit yield and generating constraints in the international market. The application of the sterile insect technique (SIT) continues to reveal areas where new technologies can improve the effectiveness of fruit fly control. One such advancement concerns insect strains. In the present study, a mass-reared strain of the fly with a translocation-based genetic sexing character (Salaya1) based on a brown-white pupal colour dimorphism was genetically characterized using 11 microsatellite DNA markers. Subsequently, these markers were used to evaluate the maintenance of genetic variability in the strain under mass-rearing conditions. Mating competitiveness of this strain was also tested in field cages. Two of the newly characterized Y-pseudo-linked microsatellite markers were used for strain identification in field monitoring traps. The strain was also validated in a pilot integrated pest management (IPM) programme using male-only SIT in a fruit orchard. The programme resulted in the suppression of the fruit fly population.

Intraguild predation of a generalist predator, Orius niger Wolff (Hemiptera: Anthocoridae) on Trichogramma evanescens Westwood (Hymenoptera: Trichogrammatidae), was determined in choice and no-choice experiments using a factitious host, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), under laboratory conditions. Choice and no-choice experiments were conducted in order to assess the level of intraguild predation of O. niger on E. kuehniella eggs parasitized by T. evanescens. In no-choice experiments, approximately 50 sterile (1) non-parasitized, (2) 3-day-old parasitized, or (3) 6-day-old parasitized E. kuehniella eggs were offered to 24-h-old females of O. niger in glass tubes. In choice experiments approximately 25 eggs of two of the three groups mentioned above were offered to 24-h-old O. niger females. In both choice and no-choice experiments, O. niger consumed more non-parasitized eggs of E. kuehniella. However, intraguild predation occurred, especially of 3-day-old parasitoids, but very few 6-day-old parasitized eggs were consumed. The preference index was nearly 1 indicating O. niger preferred mainly non-parasitized E. kuehniella eggs. A lower level of intraguild predation is expected under field conditions but needs to be investigated using further experiments.

Satellite DNAs are the major repetitive DNA components in eukaryotic genomes. Although satellite DNA has long been called "parasite DNA" there is substantial evidence that it could be associated with some functions of chromosome biology. Ladybird beetles (Coccinellidae) are one of the largest and most important groups of beetles. Many ladybirds are of economic interest as biological control agents because they eat some agricultural pests such as aphids and scale insects. However, other species are phytophagous and can damage crops. Despite the ecological importance of the latter group there are no studies on their satellite DNA. A satellite DNA family was isolated and characterized in the ladybird Henosepilachna argus. This satellite DNA is organized in tandem repeats of 658 bp and is A + T rich (67.3%). The recorded high sequence conservation of the monomers together with the detection of putative gene conversion processes indicate concerted evolution. Reverse transcription polymerase chain reaction (RT-PCR) revealed that this satellite DNA is transcribed and in situ hybridization its location in the subtelomeric regions of all chromosomes except the long arm of the X chromosome. The presence of this satellite DNA in other species of the genus Henosepilachna and Epilachna was also tested using PCR. The results indicate that this satellite DNA sequence is so far specific to H. argus.

RNA interference (RNAi) technology uses dsRNAs to silence specific targeted genes by downregulating their expression. It has become a potent tool for functional and regulatory studies of insect genes and has potential to be applied for insect control. Though it has been challenging to generate effective RNAi in lepidopteran insects, in the current study this technology was applied to develop specific RNAi-based molecular tools that could be used to negatively impact the invasive lepidopteran forest pest, gypsy moth (GM). GM midgut-specific genes were selected for dsRNA design from larval transcriptome profiles. Two methods were used to produce specific dsRNAs, bacterial expression and in vitro synthesis, which were then fed per os to GM larvae. Depletion of uncharacterized gene targets known as locus 365 and locus 28365, or their stacked combination, depleted target transcripts in a sequence specific manner and resulted in 60% reduction in body mass. Treated GM females that were able to moult to the adult stage displayed an approximately two-fold reduction in egg masses. These have potential to be developed as molecular biopesticides for GM.

Flowers of dicotyledonous plants host communities of arthropod species. We studied the community associated with dandelion (Taraxacum section Ruderalia), a complex of apomictic micro-species abundant in central Europe. Identification of microspecies in the field was impracticable. These plants produce an abundance of flowers that host arthropod communities that are not yet fully documented. We investigated species occurrence, its diurnal and seasonal variation and some of the factors that determine the abundance of the dominant species. Insect and spiders were collected from 2010 to 2012 at a locality in Prague. Whole capitula were harvested at weekly intervals and resident arthropods were identified. Diurnal variation in insect presence and the effect of pollen and microclimate on some of the species were also examined. The insect community (> 200 species) consisted mainly of species of Hymenoptera (86 spp.), Coleoptera (56 spp.), Diptera (46 spp.) and Heteroptera (23 spp.). The most abundant were Thysanoptera (2 spp.). Pollen eaters/collectors and nectar feeders dominated over predators and occasional visitors. From April to mid-August, the insect community was dominated by Coleoptera, and later by Diptera and Hymenoptera. Except for Meligethes spp. and species breeding in the capitula, the insects occupied flowers during the daytime when the flowers were open (10-12 h in spring and only 2-4 h in late summer). The presence of Meligethes spp. in particular flowers was associated with the presence of pollen; the occurrence of Byturus ochraceus with pollen and flower temperature. Although pollination is not necessary, dandelion plants produce both nectar and pollen. The community of arthropods that visit dandelion flowers is rich despite their being ephemeral. The composition of local faunas of flower visitors, presence of floral rewards and flower microclimate are important factors determining the composition of the flower community.

Termites are important decomposer due to their ability to digest cellulose and their diverse feeding habits. Trehalase is an enzyme that hydrolyzes trehalose to glucose in insects and has an important biological role. Gut morphology of wood-feeding termites (Globitermes sulphureus, Termitinae; Microcerotermes crassus, Termitinae and Bulbitermes prabhae, Nasutitermitinae) and fungus-growing termites (Macrotermes annandalei, Macrotermitinae) that belong to the family Termitidae was determined in this study. Results indicate that wood-feeding termites have a similar gut morphology, which consists of a foregut, midgut and elongated hindgut, which is divided into four segments. More specifically the enlarged segment in the hindgut, called a paunch, is prominent in wood-feeding termites, whereas fungus-growing termites have a simpler tubular gut with a very small paunch. Trehalase activity was high in the midgut of wood-feeding termites (G. sulphureus, Mi. crassus and B. prabhae), but in the fungus-growing termite (Ma. annandalei) the highest level of activity was recorded in the hindgut. Cellulase activity (endo-β-1,4-glucanase) was detected in all gut segments with very high levels in the hindguts of B. prabhae and Ma. annandalei. Differences in the distribution of trehalase and gut morphology correspond to the phylogenetic analyses of Termitidae, which indicate that Macrotermitinae is the sister group of Termitinae and Nasutitermitinae. In addition, validamycin suppressed trehalase activity in termites in vitro and in vivo, resulting in a high mortality in wood-feeding and fungus-growing termites, indicating that trehalase inhibitors could be useful tools for termite control.

To explore the debated phylogenetic relationship of two Hesperiidae subfamilies, Pyrginae and Eudaminae, and contribute to the understanding of the evolution of mitogenomic architecture in butterflies, we sequenced the complete mitogenome of Tagiades vajuna. The mitogenome is a typical circular duplex molecule of 15,359 bp. Apart from the standard 22 tRNAs, it has a tandem duplication of trnS(AGN) and trnE, which is unique in lepidopteran insects. Comparison with Ctenoptilum vasava indicates that the trnS1 duplication is not an ancestral state shared with other species of Tagiadini. Independent origin of the trnS1 duplications was further confirmed by the reconstruction of the ancestral character state based on the topology of the phylogram. Furthermore, comparative analysis of mitogenomes with and without tRNA duplications indicates that tRNA duplication does not alter the codon usage pattern. The mitogenome has negative AT- and GC-skews, and it is highly A+T-biased (79.7%). The AT-rich (or control) region (283 bp) contains "ATAGA" and "ATTTA" motifs. Regarding the phylogenetic analysis, we found that removal of the third codon position (3CP) from datasets used for the mitochondrial phylogenomics of Hesperiidae is likely to produce results that are more consistent: Pyrginae were rendered paraphyletic by Eudaminae in both analyses of the dataset from which the 3CP was removed (13 PCGs + all RNAs), but inclusion of the 3CP resulted in a destabilized topology, resulting in both monophyly and polyphyly. We conclude that even shallow-phylogenies of insects should pay close attention to compositional and mutational biases in mitogenomes.

We studied assemblages of carabids in eight similar habitats, five in Slovakia and three in Serbia. The ground beetles were caught by pitfall traps from February 2015 until November 2016. We compared the incidence of Carabidae in floodplain forests and ecotones alongside the River Danube in Slovakia and the Rivers Tisza and Begej in Serbia. We determined their association with anthropogenic effects,diversity of plants in the different vegetation layers, cover of vegetation layers (herbaceous plants, shrubs and trees), area of forest stands, circumference of forest stands, distance to forest edge, age of forest stands, depth of leaf litter and physico-chemical properties of soil and leaf litter (conductivity, pH, relative content of H, C, P and N). In total, 2,495 adult individuals of 110 species of carabids were collected. The total epigeic activity of the carabids was significantly and positively associated with the number of species of plants in E₃ vegetation layer and the relative content of N, and negatively with the cover of the E₁ layer. Species richness was significantly positively associated with the number of species of plants in the E₃ layer and the pH of leaf litter, but an opposite trend in evenness.

Body size is a standard criterion of quality control in insect rearing and often assumed to correlate with fitness in parasitoid wasps, but various metrics of body size can be used. The purpose of this study was to determine which morphological feature provides the best correlation with body size and egg load in a thelytokous population of the parasitoid wasp, Lysiphlebus fabarum (Marshall), when reared on Aphis fabae Scopoli under standardized conditions in a growth chamber (21 ± 1°C, 60-70% RH, and 16L : 8D). Candidate metrics included head width, length and width of the pronotum, length and width of the right forewing, and length of the right hind tibia. In the first experiment, correlations were determined between these measurements and overall wasp body length. As head width and hind tibia length emerged as the most suitable proxies for total body length, the next experiment these two variables as proxies for egg load in females reared from different nymphal instars of the host aphid. There was a non-linear relationship between body size and egg load of wasps emerging from hosts parasitized in different nymphal instars. Egg load increased linearly with body size across all host growth stages, but the second nymphal instar was the most suitable stage for parasitism when speed of development was factored in. The results suggest that head width is a suitable morphometric for monitoring quality control in mass-reared cultures of this wasp.

Insect pests cause billions of dollars in crop losses and there is the ever-present threat of insecticide resistance, pesticide pollution of food and environmental damage. New ways of controlling insect pests are urgently needed. Arginine kinase (AK) is a phosphotransferase, which plays a critical role in cellular energy metabolism in invertebrates. It only presents in invertebrates and may be a suitable chemotherapeutic target in the control of pests. In this study, we cloned and characterized the full-length AK gene from Phyllotreta striolata, one of the most destructive beetle pests worldwide. Furthermore, we constructed a dsRNA targeting AK and used RNAi to control the beetle. The feeding bioassays indicated that minute quantities of dsRNA greatly impaired the beetle's development. Ingestion of dsRNA not only significantly retarded the development and increased the mortality of adults, it also greatly reduced fecundity and fertility, suggesting that RNAi targeting AK is a potential and attractive tool for controlling insect pests.

A chamber, named SOIL-INSECT toolbox, was developed to analyse the effect of various factors on the behaviour of soil-dwelling insects. It is equipped with sensors that continuously monitor the concentration of CO₂ in the different compartments of the chamber without disturbing the air balance in the soil. The chamber can be adapted to study different stimuli, including volatile compounds, both in the presence and absence of plants. The chamber was tested using the larvae of Melolontha spp., which confirmed its suitability for carrying out complex studies on insect-insect and insect-plant-microbiome interactions in a complex environment such as soil. The results of behavioural experiments using L3 larvae of Melolontha spp. in sterilized and natural soils revealed that the soil condition affected the behaviour of the larvae, likely due to its effect on the soil microbiome and physico-chemical characteristics.

The brown marmorated stink bug, Halyomorpha halys, is a polyphagous species from eastern Asia, which has spread to America and Europe where it damages many crops. In recently colonized areas, facilitative interactions between H. halys and native insects are poorly investigated. In this study, we report for the first time facilitation of native wasp and ant feeding by H. halys in Europe. The facilitation was related to the outflow of plant exudates caused by H. halys feeding on manna ash trees, where they have aggregated in response to an aggregation pheromone, which then attracted species of Hymenoptera to the infested trees. Trees other than manna ash were not involved in the facilitation between these two taxa. The species that frequently visited infested manna ash were Polistes dominula, Vespa crabro, Formica (Serviformica) cunicularia and Lasius emarginatus, while Polistes cf. nimpha, Vespula germanica, Crematogaster scutellaris and Tapinoma subboreale were occasional visitors. The numbers of wasps and ants feeding on plant exudates differed at different times in a day, with more Hymenoptera foraging in the afternoon, when more H. halys individuals were actively feeding. Facilitative interactions, such as those recorded in this study, are important for furthering our understanding of the ecology of invasive species in terms of creating sources of food for native organisms.

Rab proteins are small GTP-binding proteins and are the largest family in the Ras GTPase superfamily and mediate vesicular transport in cells. Diverse insulin-like peptides, such as bombyxin, are synthesized in the brain and secreted into the haemolymph by the corpus allatum (CA). In the brain of Bombyx mori, Rabs are expressed in a specific area; however, which Rabs actually link the secretion of bombyxin remains unknown. A double-staining analysis of nine Rabs (Rab1, 3, 6, 7, 14, 21, 26, 39 and X4) and bombyxin indicated that Rab3-, Rab7-, Rab39- and RabX4-immunohistochemical reactivity (ir) areas overlapped with bombyxin-ir in the brain and CA in B. mori, while Rab6-, Rab14- and Rab21-irs partially overlapped in the CA. Rab1-ir occurred in the other immunopositive areas in CA. Rab26-ir did not occur in the brain. Rab39-ir occurred in UNC104, Rab39- effector, -immunopositive neurons in the brain and CA. Thus, Rab3, 7, 39 and X4 may regulate the exocytosis of bombyxin.

Phenotypic diversity depends on genotype diversity, but the degree of genotype-by-environment interaction is species-specific. Red wood ants (Formica s. str) are keystone species in boreal forests and very variable phenotypically. These variations are used for species identification and proposed as ecological indicators of anthropogenic disturbances. However, their origin is unknown. Here we aimed to provide a preliminary answer to this question and outline the direction for future research. We determined the interrelation between nest mate worker relatedness (kinship) and the diversity of colour morphs, degree of melanisation and size of the red wood ant, Formica rufa. In Finnish populations of this species polyandry, which involves multiple mating by queens is the principal determinant of the relatedness between workers. We hypothesised, that if phenotypic diversity is a result of genetic diversity, then polyandrous colonies should produce more phenotypically diverse workers. A total of 336 individuals belonging to 20 colonies were used for this study. We collected ants from coniferous and broadleaf forests in Finland, fixed them in 96% alcohol, then digitally photographed, genotyped and analysed the phenotypic variation. The average colony nest mate worker relatedness was used as an estimate of the level of polyandry (more than one if r < 0.6). Our results revealed no associations between the diversity of the phenotypic traits measured and worker kinship in F. rufa. As a further step to reveal the degree of genotype-by-environment interaction in determining the colour traits of the red wood ant we suggest more sophisticated genetic studies indicating the heritability of phenotypic traits between patrilinies and testing of environmental factors such as temperature, humidity, UV-radiation, food and pollution.

Temperature is an important factor for invertebrates. Social insects build nests, which along with their ability to thermoregulate, provide shelter from extreme temperatures. However, for many species of ants the most common method of controlling the temperature inside a nest is to choose a suitable nest site. During a field experiment, the choice of nest site by the acorn ant Temnothorax crassispinus, a species which lives in coniferous and mixed forests, was studied. It typically occupies ephemeral nest sites and can move to a new nest site several times in one season. It was predicted that in early spring, dark coloured nest sites would be warmer and thus more frequently occupied by ant colonies. Contrary to this prediction, no difference was recorded in the frequency with which dark and lighter coloured nests were occupied. However, also in contrast to the prediction, in forest in early spring the difference in temperature inside different coloured nests was small. Thus, other features of nests, e.g., volume of cavity, are probably more important in determining nest site selection by this ant.

The influence of early arriving species on the establishment and activity of later ones (the priority effect) is a key issue in ecological succession. Priority effects have been extensively studied in communities subject to autotrophic succession (plants, sessile animals), but only sporadically studied in communities subject to heterotrophic succession (e.g. dung or carrion inhabiting communities). We studied the influence of early successional colonizers on late successional colonizers by manipulating the successional processes in cow dung pats via delaying, and thus lowering, colonization by early successional insects. The decreased activity of early successional insects did not affect the species richness of late successional insects, but it did lead to increased abundance of colonizers. Late successional coprophagous beetles were facilitated by early successional species while larvae of late successional coprophagous flies were inhibited, presumably, by the larvae of early successional flies. We therefore propose that both facilitation and inhibition have a role to play in the heterotrophic succession of coprophilous insects. In addition, facilitation and inhibition among taxa seems to reflect their evolutionary relationships, with facilitation being prominent between phylogenetically distant lineages (early successional Diptera and late successional Coleoptera), and inhibition being more common between closely related lineages (early vs. late successional Diptera). These patterns are strikingly reminiscent of the situation in the autotrophic succession of plants.