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Diversity of adipokinetic hormones in termites (Isoptera)Original articleVeronika JEDLIÈKOVÁ, Pavel JEDLIÈKA, Barbora ©PULÁKOVÁEur. J. Entomol. 113: 364-371, 2016 | DOI: 10.14411/eje.2016.047 In this study we report on the structural diversity of adipokinetic hormones (AKHs) in the evolutionarily oldest group of social insects, the termites (Isoptera). Using molecular methods combined with in silico bioinformatic analysis, we studied and compared the sequences coding for these neuropeptides in thirteen species of five families of Isoptera. There are three types of AKH octapeptides in termites: Empusa pennata adipokinetic hormone (Emppe-AKH; pQVNFTPNWamide), Microhodotermes viator corpus cardiacum peptide (Micvi-CC; pQINFTPNWamide) and Periplaneta americana cardioaccelerating hormone (Peram-CAH-I; pQVNFSPNWamide). Of these the Peram-CAH-I was the most frequently bioactive form detected in representatives of four out of the six families studied. The complete AKH preprohormones in the termites studied shared at least an 84% amino acid similarity. In agreement with current phylogenetic scenarios of termites as an internal monophyletic clade nested within cockroaches (Blattaria) in the proximity of the family Blattidae, our phylogenetic analysis of the AKH precursor sequences (in the absence of data for the Cryptocercidae) placed the Blattidae (Periplaneta americana) as a sister group of termites and the AKHs of other cockroach families (Blattellidae and Blaberidae) were more divergent from those of termites. Representatives of the basal termite families Mastotermitidae and Archotermopsidae (but also one rhinotermitid genus Prorhinotermes) occurred separately from the phylogenetically advanced lineage (Rhinotermitidae and Termitidae), and Neotermes (Kalotermitidae) was sister to all other termites included. |
Comparative efficiency of traps for horse fly (Diptera: Tabanidae) survey in riparian oak-ash forests in Danube floodplainOriginal articleAlma MIKU©KA, Selma MLINARIÆ, Lidija BEGOVIÆ, Erin CURRANEur. J. Entomol. 113: 531-536, 2016 | DOI: 10.14411/eje.2016.072 The objective of this work was to evaluate the relative trap efficiency of the three modified traps baited with 1-octen-3-ol as attractant, Box, Nzi and Canopy, for horse fly (Tabanidae) survey. Nine traps (three traps per trap type) were tested in 3 × 3 Latin square designs during summer 2011 in riparian oak-ash forests in the Danube floodplain of Croatia. Overall, the traps caught 1,986 specimens of 11 horse flies species during the study period. The most abundant species caught was Tabanus bromius (58%), followed by Tabanus tergestinus (21%), Tabanus maculicornis (16%), Tabanus sudeticus (2%), Atylotus loewianus (1%) and Tabanus autumnalis (1%). Both the Box traps and the Nzi traps had significantly greater catch efficiencies than the Canopy traps (βbox = 2.47, X2 = 65.48, df = 1, P < 0.001 and βnzi = 1.54, X2 = 25.12, df = 1, P < 0.001, respectively). Nzi traps had a catch rate 4.65 (95% CI: 2.55, 8.48) times greater than Canopy traps and Box traps had a catch rate 11.77 (95% CI: 6.48, 21.39) times greater than Canopy traps. Based on Shannon-Wiener diversity indices Nzi traps were better suited for diversity survey and had higher (H' = 1.33) indices than Box (H' = 1.08) or Canopy traps (H' = 1.00). |
Polygalacturonase gene expression and enzymatic activity in salivary glands of laboratory reared and wild populations of Lygus lineolaris (Hemiptera: Miridae)Original articleDaniel FLEMING, Natraj KRISHNAN, Fred MUSSEREur. J. Entomol. 114: 16-24, 2017 | DOI: 10.14411/eje.2017.003 Lygus lineolaris (Palisot de Beauvois, 1818) (tarnished plant bug) is a serious pest of cotton (Gossypium hirsutum L.) in the Delta region as compared to cotton in the Hills region of the state of Mississippi in USA. The reason for this is unclear but it was hypothesized that the plant cell wall degrading polygalacturonase enzyme system in the salivary glands of L. lineolaris from the Delta could be better adapted for cotton, which is grown more predominantly in the Delta region than in the Hills region. Expression analysis of three primary polygalacturonase genes (LlPG1, LlPG2 and LlPG3) was conducted in laboratory reared and field collected populations of L. lineolaris. Assay of polygalacturonase enzyme activity was also conducted to compare wild collected populations. Initial laboratory and field data revealed gene expression differences in sex, age, region, and host plant which guided the direction of our subsequent study during 2013 and 2014. Based on the results of this study, we propose that the three genes studied may not be reflective of the entire polygalacturonase enzyme system and may not be solely responsible for the observed adaptation of L. lineolaris to cotton in the Delta region than in the Hills region. Analyses also revealed that the expression of the three targeted polygalacturonase genes was affected by the host plant from which the insects were collected and that adults had higher polygalacturonase expression than nymphs. Taken together, our results provide strong evidence for developmental stage specific and host plant based change in expression of PG genes in the salivary glands of L. lineolaris. This, however, was not reflected in total polygalacturonase enzyme activity which was not significantly different between regions, hosts, sex, or developmental stage. |
The pheromone verbenone and its function in Dendroctonus armandi (Coleoptera: Curculionidae: Scolytinae)Original articleMingzhen ZHAO, Lulu DAI, Yaya SUN, Danyang FU, Hui CHENEur. J. Entomol. 114: 53-60, 2017 | DOI: 10.14411/eje.2017.008 The Chinese white pine beetle, Dendroctonus armandi Tsai and Li is a native species of bark beetle and one of the most destructive in much of western China. Little is known about the characterization of the pheromones trans-verbenol and verbenone, and their functions in D. armandi are unknown. Electroantennogram tests (EAG) and olfactory assays (Y-tube assays) in the laboratory revealed that (1) trans-verbenol may be an anti-aggregation pheromone for male and an aggregation pheromone for female D. armandi and (2) female beetles are more attracted to controls (hexane) than low concentrations of verbenone and male beetles more attracted to controls than high concentrations of verbenone. Field trials indicated that the addition of verbenone to bait used to trap D. armandi remarkably decreased the efficiency of field trapping. These results indicate that verbenone is an anti-aggregation pheromone for male D. armandi. This research provides evidence of the role of verbenone among the different types of pheromones. The pheromone verbenone clearly could be used to protect healthy Chinese white pines. |
Field and laboratory studies on drought tolerance and water balance in adult Pergalumna nervosa (Acari: Oribatida: Galumnidae)Original articleStine SLOTSBO, Jesper G. SØRENSEN, Josef STARY, Martin HOLMSTRUPEur. J. Entomol. 114: 86-91, 2017 | DOI: 10.14411/eje.2017.012 We studied the water balance, body fluid osmolality and survival of the oribatid mite, Pergalumna nervosa, when exposed to drought in field and laboratory experiments. In a replicated field experiment we artificially lowered the soil water content by putting roofs over selected plots, which reduced soil water potential to levels well below the permanent wilting percentage for plants (i.e. below -1.5 MPa). Even though a slight decrease in the abundance of P. nervosa (only found in the 0-5 cm soil layer) was recorded during the most severe drought stress (ca. -3.5 MPa), the majority of adult mites clearly survived these conditions for 3 weeks in the field without migrating to deeper soil layers. Exposing field collected adults in laboratory experiments simulating even more severe drought conditions revealed that P. nervosa can survive several weeks of gradually increasing drought stress (down to -7 MPa) with moderate water loss. The osmolality of body fluids increased as dehydration progressed, but apparently as a result of simple up-concentration of solutes and not the de novo synthesis of protective osmolytes. We compare and discuss these results in the light of what is known about other arthropods. |
A comparison of methods for sampling aquatic insects (Heteroptera and Coleoptera) of different body sizes, in different habitats using different baitsOriginal articleNata¹a TURIÆ, Martina TEMUNOVIÆ, Goran VIGNJEVIÆ, Jasenka ANTUNOVIÆ DUNIÆ, Enrih MERDIÆEur. J. Entomol. 114: 123-132, 2017 | DOI: 10.14411/eje.2017.017 Although various methods exist for sampling aquatic Heteroptera and Coleoptera in standing water, there are very few comparisons of their performance in different types of habitat. In this study, we evaluated and compared the efficiency and selectivity of three sampling methods: hand netting, bottle traps baited with canned tuna and bottle traps baited with canned cat food. The methods were compared over the period 2010-2012 in two different habitats (temporarily flooded areas and canals) in the Nature Park Kopaèki rit, a floodplain on the banks of the River Danube. The results show that the effectiveness of the method differed in the two habitats. Overall, hand netting was the most successful method, mainly in canals. Tuna fish bait was more efficient than the commonly used cat food, especially for large and highly mobile species of Dytiscidae. These findings indicate that knowing the type of habitat and the habitat preferences of aquatic insects and their activity it is possible to predict which of these methods are the best for estimating species richness. |
Adaptive significance of the prolonged diapause in the western Mediterranean lycaenid butterfly Tomares ballus (Lepidoptera: Lycaenidae)Original articleRafael OBREGÓN, Juan FERNÁNDEZ HAEGER, Diego JORDANOEur. J. Entomol. 114: 133-139, 2017 | DOI: 10.14411/eje.2017.018 Diapause is a common dormancy strategy exhibited by many species of invertebrates and insects to temporarily avoid seasonally recurring unfavourable conditions for their development, most usually in winter. Less frequently, a prolonged diapause lasting two or more years is described in species living in unpredictable environments where it is adaptive, but with significant costs. In this paper we examine the occurrence of prolonged diapause in the lycaenid butterfly Tomares ballus. Pupae of this species undergo an obligate diapause from mid-May to late January the following year. However, during our rearing experiments (from 2009 to 2016) the emergence of adults occurred sequentially and a fraction of the pupae remained in diapause for up to seven years. The annual percentage emergence after the first year of diapause was 45.6%, and only barely exceeded 50.0% in 2015. Remarkably, 12 pupae (11.4% of the initial brood) remained in diapause in their eighth year. The negative exponential equation fitted to the emergence data suggests that further emergences may occur within the next five years. Therefore, the potential for successful prolonged diapause of T. ballus pupae may be more than 10 years. The adaptive value of this strategy is discussed in relation to the effects of adverse and unpredictable weather during the flight period of the butterfly, intra-guild competition, parasitoids and changes in habitat quality. We suggest that this strategy may also be exhibited by other species of Mediterranean lycaenids. |
Double strand RNA-mediated RNA interference through feeding in larval gypsy moth, Lymantria dispar (Lepidoptera: Erebidae)Original articleSaikat Kumar B. GHOSH, Dawn E. GUNDERSEN-RINDALEur. J. Entomol. 114: 170-178, 2017 | DOI: 10.14411/eje.2017.022 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. |
Structure of scuttle fly communities (Diptera: Phoridae) in two habitats on a Mediterranean mountainOriginal articleCarlos GARCÍA-ROMERA, José A. BARRIENTOSEur. J. Entomol. 114: 203-214, 2017 | DOI: 10.14411/eje.2017.025 Phoridae (scuttle flies) are widely distributed, occur in many types of habitats and are ecologically versatile, which makes them an excellent bioindicator group for evaluating faunal diversity. The structure of scuttle fly communities was compared in two Mediterranean habitats in the Montseny Natural Park (Catalonia, Spain) that differ in vegetation and microclimate: beech forest and highland scrubland. 3684 male individuals belonging to 135 species of scuttle flies were identified. Scuttle flies were more abundant in beech forest than scrubland. Observed and estimated species richness were lower in scrubland than in beech forest, while diversity was similar in both habitats. Community evenness was greater in scrubland than beech forest. Therefore, the percentage of dominant and subdominant species was higher in scrubland than beech forest, while the percentage of rare species was higher in beech forest than scrubland. Scuttle fly species composition was significantly different in the two habitats, but it was similar among plots within the same habitat. Megaselia pectoralis (Wood, 1910) and Megaselia subpleuralis (Wood, 1909) were the dominant species in beech forest, while Megaselia pusilla (Meigen, 1830), Megaselia pumila (Meigen, 1830), Megaselia superciliata (Wood, 1910) and Megaselia diversa (Wood, 1909) were the dominant species in scrubland. Trophic specialization was higher in beech forest than scrubland. Saprophages were the dominant trophic group in beech forest, while fungivores and polyphages were dominant in scrubland. The high biodiversity of scuttle flies recorded in the Montseny Natural Park indicates that there is also a high diversity of other taxa there and that these Mediterranean mountains are of high conservation status. |
Do the arthropod communities on a parasitic plant and its hosts differ?Original articleAlba LÁZARO-GONZÁLEZ, José A. HÓDAR, Regino ZAMORAEur. J. Entomol. 114: 215-221, 2017 | DOI: 10.14411/eje.2017.026 Parasitic plants growing on tree branches may be a novel niche and phytoresource for arthropods. The spatial continuity between hosts and their parasites in canopies might provide a homogeneous environment for arthropod communities, but differences in mistletoe leaves and host needles could be exploited by different species of arthropods. Therefore, it is important to determine insect-community assemblages in order to discover the role of parasitic plants as a different habitat for arthropods. Thus, we aim to evaluate the level of similarity between the arthropod community on mistletoe (Viscum album) and that on its two principal pine hosts, Black pine (Pinus nigra) and Scots pine (P. sylvestris), on a Mediterranean mountain. Our results reveal that, irrespective of the species of pine host, V. album has a stable, independent and simple arthropod trophic web, composed mainly of two specialist hemipteran herbivores, Cacopsylla visci (Psyllidae) and Pinalitus viscicola (Miridae), and a hemipteran predator, Anthocoris visci (Anthocoridae). Despite this, the composition of the arthropod communities differed significantly on both host species, with a greater richness and diversity on Scots than Black pine and these differences are not reflected in the community on mistletoe. Overall, we conclude that, although Viscum album is considered to be a pest of pine, its presence increases the heterogeneity of the forest canopy by providing a novel habitat for a new and specific community of arthropods. In addition, this is a new record for and most probably an extension of the southernmost limit of the known geographical distribution of the arthropod community inhabiting V. album. |
Warp-speed adaptation to novel hosts after 300 generations of enforced dietary specialisation in the seed beetle Callosobruchus maculatus (Coleoptera: Chrysomelidae: Bruchinae)Original articleThomas N. PRICE, Aoife LEONARD, Lesley T. LANCASTEREur. J. Entomol. 114: 257-266, 2017 | DOI: 10.14411/eje.2017.031 Herbivorous insects are often highly specialised, likely due to trade-offs in fitness on alternative host species. However, some pest insects are extremely adaptable and readily adopt novel hosts, sometimes causing rapid expansion of their host range as they spread from their original host and geographic origin. The genetic basis of this phenomenon is poorly understood, limiting our ability to predict or mitigate global insect pest outbreaks. We investigated the trajectory of early adaptation to novel hosts in a regionally-specialised global crop pest species (the cowpea seed beetle Callosobruchus maculatus). After experimentally-enforced dietary specialisation for nearly 300 generations, we measured changes in fitness over the first 5 generations of adaptation to 6 novel hosts. Of these, C. maculatus reproduced successfully on all but one, with reduced fitness observed on three hosts in the first generation. Loss of fitness was followed by very rapid, decelerating increases in fitness over the first 1-5 generations, resulting in comparable levels of population fitness to that observed on the original host after 5 generations. Heritability of fitness on novel hosts was high. Adaptation occurred primarily via changes in behavioural and phenological traits, and never via changes in offspring survival to adulthood, despite high heritability for this trait. These results suggest that C. maculatus possesses ample additive genetic variation for very rapid host shifts, despite a prolonged period of enforced specialization, and also suggest that some previously-inferred environmental maternal effects on host use may in part actually represent (rapidly) evolved changes. We highlight the need to examine in more detail the genetic architecture facilitating retention of high additive genetic variation for host shifts in extremely adaptable global crop pests. |
Survival, body mass and potential fecundity of the invasive moth Cameraria ohridella (Lepidoptera: Gracillariidae) on its original host plant Aesculus hippocastanum and Aesculus glabraOriginal articleUrszula WALCZAK, Edward BARANIAK, Piotr ZDUNIAKEur. J. Entomol. 114: 295-300, 2017 | DOI: 10.14411/eje.2017.036 Performance of the invasive horse-chestnut leaf miner, Cameraria ohridella Deschka & Dimic, 1986 (Lepidoptera: Gracillariidae), was studied on two host plants: the white-flowering horse-chestnut Aesculus hippocastanum L. and the Ohio buckeye Aesculus glabra Willd. C. ohridella developed successfully on both host plants; however, mine density and survival were much higher on A. hippocastanum than on A. glabra. The pupal mass and potential fecundity were strongly affected by the host plant on which the larvae fed. On A. hippocastanum pupae were significantly heavier and females more fecund than those on A. glabra. Furthermore, on both host plants there was a significant positive correlation between the number of oocytes in ovaries and pupal body mass, and as a consequence, heavier females produced more eggs. Our study demonstrates that the mine density, survival, pupal mass and potential fecundity were significantly lower on A. glabra than on A. hippocastanum. The observed lower performance of C. ohridella on the exotic host plant was assumed to be due to its poor food quality (nutritional and chemical composition). |
Metagenomic survey of bacteria associated with the invasive ladybird Harmonia axyridis (Coleoptera: Coccinellidae)Original articleKrzysztof DUDEK, Kinga HUMIÑSKA, Jacek WOJCIECHOWICZ, Piotr TRYJANOWSKIEur. J. Entomol. 114: 312-316, 2017 | DOI: 10.14411/eje.2017.038 The Asian ladybird Harmonia axyridis is an invasive insect in Europe and the Americas and is a great threat to the environment in invaded areas. The situation is exacerbated by the fact that non native species are resistant to many groups of parasites that attack native insects. However, very little is known about the complex microbial community associated with this insect. This study based on sequencing 16S rRNA genes in extracted metagenomic DNA is the first research on the bacterial flora associated with H. axyridis. Lady beetles were collected during hibernation from wind turbines in Poland. A mean ± SD of 114 ± 35 species of bacteria were identified. The dominant phyla of bacteria recorded associated with H. axyridis were Actinobacteria, Proteobacteria, Firmicutes and Bacteroidetes. Representatives of these phyla are common in the environment, e.g. in the soil, and are often identified as the dominant bacteria associated with arthropods. We also identified animal pathogenic bacteria, such as Burkholderia, Rhodococcus, Chlamydiae and Anaplasmataceae spp. (Neorickettsia helminthoeca and Ehrlichia ovina). We also identified Wolbachia pipientis in a single beetle. This bacterium is a causative agent of reproductive alterations in arthropods. These results support the enemy release hypothesis in the case of this ladybird invasion. Pathogenic bacteria were recorded in only a few samples. Moreover, male-killing bacteria such as Spiroplasma spp., Wolbachia spp. and Rickettsia spp. were only recorded in single insects so they cannot be responsible for the observed alterations in the sex-ratio of the ladybird population studied. |
Response of ground-dwelling harvestman assemblages (Arachnida: Opiliones) to European beech forest canopy coverOriginal article¥udmila ÈERNECKÁ, Ivan MIHÁL, Benjamín JARÈU©KAEur. J. Entomol. 114: 334-342, 2017 | DOI: 10.14411/eje.2017.042 We studied the effects of the overstory canopy cover on ground-dwelling harvestmen communities in European beech forests in the Western Carpathian Mts. We analyzed the differences in species richness, abundance and composition in two tree canopy cover categories (closed and open canopy). Overall, 1765 individuals belonging to 16 species were caught using pitfall traps. Repeated-measures ANOVA revealed that under both closed and open canopies a similar absolute and rarefied species richness and number of individuals (standardized to 100 pitfall trap days) were caught, and that both species richness and abundance were affected by the season (i.e., time of trap replacement); yet the total number of individuals trapped was more than two times greater under the open canopy than under the closed canopy. Despite the subtle differences in the taxonomic composition of the catches under the open and closed canopies revealed by DCA followed by RDA, the composition of ground-dwelling harvestmen assemblages differed under the two canopy covers. The open canopy was more suitable for heliophilic, xerothermic eurytopic harvestmen species typical for open and ecotonal habitats, such as Egaenus convexus (C.L. Koch) and Oligolophus tridens (C.L. Koch) but still suitable for hemihygrophilic Lophopilio palpinalis (Herbst). The closed canopy stands were preferred by shade-tolerant, hygrophilic eurytopic harvestmen species, such as Trogulus sp. Latreille, Dicranolasma scabrum (Herbst) and Platybunus bucephalus (C.L. Koch). Our results highlight the importance of intra-habitat heterogeneity of a harvestmen community. |
Tandem duplication of two tRNA genes in the mitochondrial genome of Tagiades vajuna (Lepidoptera: Hesperiidae)Original articleFang-Fang LIU, Yi-Ping LI, Ivan JAKOVLIÆ, Xiang-Qun YUANEur. J. Entomol. 114: 407-415, 2017 | DOI: 10.14411/eje.2017.052 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. |
Preliminary evidence of the horizontal transmission of Wolbachia between Crioceris leaf beetles (Coleoptera: Chrysomelidae) and their Asparagus host plantsOriginal articleMicha³ KOLASA, Matteo MONTAGNA, Valeria MEREGHETTI, Daniel KUBISZ, Mi³osz A. MAZUR, £ukasz KAJTOCHEur. J. Entomol. 114: 446-454, 2017 | DOI: 10.14411/eje.2017.057 Intracellular bacteria of the genus Wolbachia (α-Proteobacteria) are the most widespread endosymbionts of insects. Host infection is usually associated with alterations in reproduction, such as cytoplasmic incompatibility, the induction of parthenogenesis and offspring sex ratio bias: all phenomena that may influence host speciation. In the present study, by using well-established molecular tools, we investigated the presence of Wolbachia in leaf beetles of the genus Crioceris and their host plants, which are various species of Asparagus. Multilocus sequence typing of bacterial genes showed that despite their occurrence in the same habitat and feeding on the same plant, two species of Crioceris, C. quinquepunctata and C. quatuordecimpunctata, are infected by two different strains of Wolbachia. C. asparagi, C. paracenthesis and C. duodecimpunctata, which are sympatric with the infected species, do not harbour the bacterium. Interestingly, DNA of Wolbachia was detected in host plant tissues that are exploited by the beetles, providing evidence for the horizontal transmission of the bacterium between beetles and their host plants. Moreover, Wolbachia was detected in species of Crioceris that are not closely related. |
More complex than expected: Cold hardiness and the concentration of cryoprotectants in overwintering larvae of five Erebia butterflies (Lepidoptera: Nymphalidae)Original articlePavel VRBA, Oldøich NEDVÌD, Helena ZAHRADNÍÈKOVÁ, Martin KONVIÈKAEur. J. Entomol. 114: 470-480, 2017 | DOI: 10.14411/eje.2017.060 Understanding the factors restricting the distribution of some insect species to high altitudes is hindered by poor knowledge of temporal changes in their cold hardiness during overwintering. We studied overwintering larvae of five species of Erebia butterflies (Lepidoptera: Nymphalidae: Satyrinae) differing in altitudinal distribution: lowland E. medusa, submountain E. aethiops, subalpine E. pronoe, alpine E. cassioides, and subnivean E. pluto. We subjected them to three treatments, AutumnWarm (13/8°C), imitating conditions prior to overwintering; AutumnCold (5/0°C), imitating late autumn conditions; and WinterCold (5/0°C), differing from AutumnCold by a shorter photoperiod and longer exposure to zero temperatures. Supercooling points (SCP) did not differ between species in the AutumnWarm treatment, despite large differences in the concentrations of cryoprotectants (CrPC; lowest in E. medusa and E. aethiops). Lowland E. medusa was freeze-tolerant, the subalpine, alpine and subnivean species were freeze-avoidant, whereas submountain E. aethiops displayed a mixed strategy. SCPs diverged in the AutumnCold treatment: it increased in the lowland E. medusa (from -16.5 to -10.8°C) and reached the lowest value in E. cassioides (-21.7°C). In WinterCold, SCP increased in subalpine E. pronoe (from -16.1°C in AutumnWarm and -18.7°C in AutumnCold to -12.6°C). E. medusa decreased and E. aethiops increased their CrPCs between autumn and winter; the highest CrPC was recorded in subnivean E. pluto. CrPC did not correlate with SCP across species and treatments. Cryoprotectant profiles corroborated the difference between lowland and freeze-tolerant E. medusa and the three high altitude freeze-avoidant species, with E. aethiops in an intermediate position. Glycerol was surprisingly rare, trehalose was important in all species, and such rare compounds as monopalmitin and monostearin were abundantly present in E. pronoe, E. cassioides and E. pluto. |
Characterization and transcriptional analysis of a subtelomeric satellite DNA family in the ladybird beetle Henosepilachna argus (Coleoptera: Coccinellidae)Original articlePablo MORA, Jesús VELA, Areli RUIZ-MENA, Teresa PALOMEQUE, Pedro LORITEEur. J. Entomol. 114: 481-487, 2017 | DOI: 10.14411/eje.2017.061 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. |
Comparison of gut morphology and distribution of trehalase activity in the gut of wood-feeding and fungus-growing termites (Isoptera: Termitidae)Original articleNujira TATUN, Chutamas SAWATNATHI, Suwakan TANSAY, Jatuporn TUNGJITWITAYAKULEur. J. Entomol. 114: 508-516, 2017 | DOI: 10.14411/eje.2017.065 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. |
Chromosome mapping of 28S ribosomal genes in 11 species of Cassidinae (Coleoptera: Chrysomelidae)Original articleAmália T. LOPES, Flávia R. FERNANDES, Marielle C. SCHNEIDEREur. J. Entomol. 114: 546-553, 2017 | DOI: 10.14411/eje.2017.069 In this study, we examined for the first time the distribution of the 28S ribosomal genes in beetles of the subfamily Cassidinae. More than 55% of the species in this subfamily have a similar karyotype, 2n = 16 + Xyp. For this work, we selected species belonging to the tribes Cassidini and Mesomphaliini, which have, respectively, the most conserved and diversified karyotype characteristics within the Cassidinae. An analysis of 11 species revealed that rDNA sites on one pair of autosomes is the most frequent pattern, occurring in 10 species. This condition occurs in the seven genera examined and in species of both of the tribes, Cassidini and Mesomphaliini. Nevertheless, the differences in the locations of 28S rDNA were more pronounced in the tribe Cassidini and among species with similar karyotype characteristics. On the other hand, in Mesomphaliini, the increase in the diploid number was not accompanied by an increase in the number of ribosomal sites. Moreover, the comparison of the number and localization of major rDNA sites with the distribution of constitutive heterochromatin indicates that there is no direct correlation between the dispersion of constitutive heterochromatin and 28S rDNA genes in Cassidinae. |
Windborne migration of Auchenorrhyncha (Hemiptera) over BritainOriginal articleDon R. REYNOLDS, Jason W. CHAPMAN, Alan J.A. STEWARTEur. J. Entomol. 114: 554-564, 2017 | DOI: 10.14411/eje.2017.070 Planthoppers (Delphacidae), leafhoppers (Cicadellidae) and froghoppers (Aphrophoridae) (Hemiptera: Auchenorrhyncha) caught during day and night sampling at a height of 200 m above ground at Cardington, Bedfordshire, UK, during eight summers (between 1999 and 2007) were consolidated with high-altitude catches made over England in the 1930s. Comparisons were made with other auchenorrhynchan trapping results from northwest Europe, which were indicative of migration. The migratory abilities in the species concerned were then interpreted in terms of various life-history traits or ecological characteristics, such as ontogenetic, diel and seasonal flight patterns, voltinism, habitat preferences, and host plant affinity. In contrast to some other areas of the world (North America, East Asia), the migratory abilities of most Auchenorrhyncha species in northwest Europe is poorly understood, and thus the present study draws together, and complements, fragmentary information on this topic as a basis for further research. |
Intraguild predation of Orius niger (Hemiptera: Anthocoridae) on Trichogramma evanescens (Hymenoptera: Trichogrammatidae)Original articleSerkan PEHLİVAN, Alican KURTULUª, Tuğcan ALINÇ, Ekrem ATAKANEur. J. Entomol. 114: 609-613, 2017 | DOI: 10.14411/eje.2017.074 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. |
Ancient and modern hybridization between Lucilia sericata and L. cuprina (Diptera: Calliphoridae)Kirstin WILLIAMS, Martin H. VILLETEur. J. Entomol. 110 (2): 187-196, 2013 | DOI: 10.14411/eje.2013.029 There are important but inconsistent differences in breeding site preference between the blow flies Lucilia sericata (Meigen, 1826) and L. cuprina (Wiedemann, 1830) (Diptera: Calliphoridae) that have significance for medical and veterinary science. These inconsistencies might arise from hybridisation. The species are difficult to distinguish using external morphology, although the male genitalia are distinctive and there are reliable molecular markers. Molecular evidence of modern hybridisation, derived from a newly developed nuclear marker, the period (per) gene, is presented here. This has implications for identifications of these species based on mtDNA, and may lead to an explanation of the medical and veterinary anomalies noted in these species. |
The role of mosaicity of the post-agriculture area of the Kampinos National Park in determining the diversity of species of spider wasps (Hymenoptera: Pompilidae)Katarzyna SZCZEPKO, Andrzej KRUK, Maciej BARTOSEur. J. Entomol. 109 (1): 35-46, 2012 | DOI: 10.14411/eje.2012.006 From 2000 to 2006 a total of 52 CPUE samples of spider wasps (Hymenoptera: Pompilidae) were collected in the mosaic landscape of the Kampinos National Park (Poland), which is a UNESCO Biosphere Reserve. The hypothesis tested was that both pompilid species richness and abundance is positively associated with spatial heterogeneity. The patterns in spider wasp assemblages were identified using a Kohonen artificial neural network (i.e., self-organizing map). The highest numbers and greatest species richness of pompilids were recorded at sites in open habitats, especially those located on dry soils that are the preferred nesting sites of ground nesting (endogeic) spider wasps. However, pompilid distribution depended not only on the character of a sampling site, but also its location in a mosaic of habitats. The highest values of pompilid abundance and species richness were also recorded at sites surrounded by several different habitats. Both parameters were lower at sites in more homogenous areas, where there were fewer habitats within the flight ranges of spider wasps. A group of three "cultural species" (Agenioideus cinctellus, A. sericeus and Auplopus carbonarius) was identified that is significantly associated with wooden buildings. The results of this study are thus consistent with the concept that habitat heterogeneity enhances faunal diversity, as each type of habitat, including anthropogenic ones, potentially contributes to a wider range of available resources. |
Patterns in diurnal co-occurrence in an assemblage of hoverflies (Diptera: Syrphidae)Manuela D'AMEN, Daniele BIRTELE, Livia ZAPPONI, Sönke HARDERSENEur. J. Entomol. 110 (4): 649-656, 2013 In this study we analyzed the inter-specific relationships in assemblages of syrphids at a site in northern Italy in order to determine whether there are patterns in diurnal co-occurrence. We adopted a null model approach and calculated two co-occurrence metrics, the C-score and variance ratio (V-ratio), both for the total catch and of the morning (8:00-13:00) and afternoon (13:00-18:00) catches separately, and for males and females. We recorded discordant species richness, abundance and co-occurrence patterns in the samples collected. Higher species richness and abundance were recorded in the morning, when the assemblage had an aggregated structure, which agrees with previous findings on communities of invertebrate primary consumers. A segregated pattern of co-occurrence was recorded in the afternoon, when fewer species and individuals were collected. The pattern recorded is likely to be caused by a number of factors, such as a greater availability of food in the morning, prevalence of hot and dry conditions in the early afternoon, which are unfavourable for hoverflies, and possibly competition with other pollinators. Our results indicate that restricting community studies to a particular time of day will result in certain species and/or species interactions not being recorded. |
Spatial distribution of Cynips quercusfolii (Hymenoptera: Cynipidae) galls on leaves and within the crowns of oak treesMarian J. GIERTYCH, Andrzej M. JAGODZIÑSKI, Piotr KAROLEWSKIEur. J. Entomol. 110 (4): 657-661, 2013 The factors that affect oviposition and consequently spatial distribution of the galls of many gall makers are poorly understood. Knowledge of these factors could result in a better understanding of the mechanisms that initiate and regulate the development of galls. We tested the hypotheses that, regardless of tree height, galls of Cynips quercusfolii L. produced agamically are distributed randomly in the crowns and on the veins of leaves of oak trees. This study was done in Poland on 15 pedunculate oak (Quercus robur) trees of various heights. We measured the areas of 1659 leaves, including 192 leaves with galls, and the distances along a vein from a gall to the petiole and from gall to leaf edge. The number of galls did not depend on tree height but depended on the position of the leaf within the crown (upper or lower). Regardless of the position in the crown, leaves with galls were significantly larger than those without galls. We conclude that galls were located at a fixed distance from the edge of leaves irrespective of leaf size, but the distance from the gall to the leaf petiole depended significantly on leaf size. We conclude that agamic females of C. quercusfolii prefer large leaves and choose the site on a leaf on which to deposit their eggs. This probably ensures that the developing gall obtains the required amount of nutrients and assimilates. |
Plant architecture and vegetation structure: Two ways for insect herbivores to escape parasitismElisabeth OBERMAIER, Annette HEISSWOLF, Hans Joachim POETHKE, Barbara RANDLKOFER, Torsten MEINERSEur. J. Entomol. 105 (2): 233-240, 2008 | DOI: 10.14411/eje.2008.033 Interactions between herbivorous insects and their parasitoids occur in highly structured and complex environments. Habitat structure can be an important factor affecting ecological interactions between different trophic levels. In this study the influence of plant architecture and surrounding vegetation structure on the interaction between the tansy leaf beetle, Galeruca tanaceti L. (Coleoptera: Chrysomelidae) and its egg parasitoid, Oomyzus galerucivorus Hedqvist (Hymenoptera: Eulophidae), was investigated at two small spatial scales in the field. It was expected that high and structurally complex plants or vegetation represent an enemy free space for the herbivore by making host search more difficult for the parasitoid. At the scale of individual plants, plant height had a positive influence on herbivore oviposition and egg clutch height a negative impact on parasitism. In addition, the beetle was more likely to oviposit on simple plants than on plants with branches, while the parasitoid remained unaffected by the degree of branching. At the microhabitat scale (r = 0.1 m around an oviposition site), both height and density of the vegetation affected beetle oviposition positively and egg parasitism negatively. The herbivore and its parasitoid, therefore, were influenced in opposite ways by habitat structure at both spatial scales investigated, suggesting the existence of an enemy free space for the herbivores' eggs on tall plants and in tall and complex vegetation. This study indicates that structural components of the environment are important for interactions among organisms of different trophic levels. |
Preference and performance of the larvae of Lymantria dispar (Lepidoptera: Lymantriidae) on three species of European oaksSlobodan MILANOVIÆ, Jelica LAZAREVIÆ, Zorica POPOVIÆ, Zoran MILETIÆ, Miroslav KOSTIÆ, Zlatan RADULOVIÆ, Dragan KARAD®IÆ, Ana VULETAEur. J. Entomol. 111 (3): 371-378, 2014 | DOI: 10.14411/eje.2014.039 The gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae), causes enormous damage to broadleaved forests in the northern hemisphere where it frequently defoliates large areas of forest. Since outbreaks begin in oak forests, its most suitable habitat, we determined the preference and performance of gypsy moth larvae when reared on three species of native oaks: sessile oak, Quercus petraea (Matt.) Liebl.; Turkey oak, Q. cerris L.; and Hungarian oak, Q. frainetto (Ten.). Leaf expansion and selected physical and chemical characteristics of the oak leaves were also measured. The shortest development time and highest relative consumption (RCR), growth rate (RGR), assimilation efficiency (AD), efficiency of conversion of ingested food (ECI) and digested food into larval biomass (ECD) values were recorded when larvae were fed on Turkey oak. Two-choice tests revealed that Turkey oak is the preferred host plant. It had the highest total soluble protein and leaf nitrogen content, lowest C/N ratio and its phenology was well synchronized with the hatching of the larvae. The worst performance and lowest preference index were recorded when fed on Hungarian oak, the leaves of which had the lowest protein and nitrogen content, while in terms of the values for preference and performance the larvae fed on sessile oak were intermediate. Our results indicate that forests with Turkey oak are highly likely to be defoliated by gypsy moth larvae and therefore should be regularly monitored. |
Temporal variations in the life-cycles of aphids (Sternorrhyncha: Aphididae) and their coccinellid predatorsMohamed El Fodhil AROUN, Bahia DOUMANDJI-MITICHE, Daniel PETIT, Zahr-Eddine DJAZOULIEur. J. Entomol. 112 (3): 432-439, 2015 | DOI: 10.14411/eje.2015.060 Aphids are either monoecious living either on trees or herbaceous plants, or heteroecious, which involves host alternating between a tree (primary host) and a herbaceous plant (secondary host). We described the temporal variations in abundance and richness of aphids in an Algerian orchard, over a 6 month period. We recorded the choice of basin colour, the relative height of traps, and monthly Barycenter of winged populations. We also recorded temporal variations in the structure of ladybird communities. Tree-living species of aphids are the last to be caught with most caught by the yellow traps, possibly because of the predominant greenness of the vegetation in April. Most were also caught by high traps. Their phenology coincides with that of the second peak of ladybirds. In contrast, the phenology of species of aphids living on herbaceous plants differs greatly, which reflects their host plant diversity. In March relatively more of these aphids were caught by the green traps, possibly because at that time the ground was not yet covered by vegetation. Early and late species of aphids are at greater risk of being attacked by ladybirds as they are also most active early and late in the season. The highest catches of the heteroecious species of aphids were recorded in the middle of the trapping period and between those of the two groups of monoecious species of aphids. The adaptive significance of the differences in the behaviour and ecology of the aphids in the three groups is discussed. |
Climate-induced changes in the phenotypic plasticity of the Heath Fritillary, Melitaea athalia (Lepidoptera: Nymphalidae)Original articleEdit JUHÁSZ, Zsolt VÉGVÁRI, János P. TÓTH, Katalin PECSENYE, Zoltán VARGAEur. J. Entomol. 113: 104-112, 2016 | DOI: 10.14411/eje.2016.013 Recently a large number of studies have reported an increase in the variability in the climate, which affects behavioural and physiological adaptations in a broad range of organisms. Specifically, insects may be especially sensitive to climatic fluctuations, as their physiology and life history traits, like those of other ectotherms, are predominantly affected by environmental factors. Here we aimed to investigate climate-induced changes in several morphometric measures of the Heath Fritillary in North-Eastern Hungary, which is a highly diverse transitional area. During this study we tested the following hypotheses: (i) climate affects genitalia and body size to various degrees (ii) increasing variability in climate induces higher levels of fluctuating asymmetry and variance in all morphological characters. To our knowledge, this study is the first to analyse simultaneously wing size and structure of genitalia of a butterfly in response to variability in climate. Our findings suggest that wing and genital traits may exhibit similar degrees of stability in response to a more variable climate, although the response in terms of forewing size differs from that of other body measurements and the structure of the genitalia. These findings suggest that global climate change may affect lepidopteran body metrics over longer periods of time. Our findings parallel the results of investigations showing that insect morphology might be modified by environmental changes, which is especially the case for those body parts that are phenotypically very variable. However, we found no evidence that increasing variability in climate would induce higher levels of fluctuating asymmetry and greater variability in morphological characters. |



