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Embryogenesis of Aphidoletes aphidimyza (Diptera: Cecidomyiidae): Morphological markers for staging of living embryosJan HAVELKA, Vladimír LANDA Jr., Vladimír LANDAEur. J. Entomol. 104 (1): 81-87, 2007 | DOI: 10.14411/eje.2007.013 Determination of embryonic stages is an important prerequisite for the long-term cryopreservation of eggs and embryos of the predatory gall midge Aphidoletes aphidimyza. This paper describes the embryonic development of this insect based on light microscopy. Gall midge embryogenesis lasts, on average, 102 h at 17°C and 144 h at 15°C. Living embryos can be quickly separated into ten stages that are clearly defined by specific morphological markers. The necessity for selecting definite embryonic stages for cryobiological storage is discussed. |
Spermathecal morphology and sperm dynamics in the female Schizocosa malitiosa (Araneae: Lycosidae)Gonzalo USETA, Bernhard A. HUBER, Fernando G. COSTAEur. J. Entomol. 104 (4): 777-785, 2007 | DOI: 10.14411/eje.2007.099 The linkage between spermathecal morphology and sperm dynamics was experimentally analysed in Schizocosa malitiosa (Tullgren, 1905) using histological serial sections and SEM. We recognised three connected sections for each spermatheca: basal atrium, stalk and head. The head ends blindly, is sclerotized, provided with few large pores, and surrounded by thick, presumably glandular epithelium. The atrium is also sclerotized, and connects with both copulatory and fertilization ducts, lying close to each other. A porous plate is located in the stalk-atrium connection. Nine adult females were fixed in eight reproductive conditions for reconstructing sperm dynamics: virgin, immediately after mating, one day after mating, three days after mating, one day after remating without oviposition (first male with a single useful palp, second male normal), immediately before oviposition, three days after oviposition, and one day after remating with oviposition (female had eaten first egg-sac and had remated). Our results suggest female control of sperm transport because the penetration of encapsulated sperm into the spermathecal head continues after mating. Stored sperm is maintained in an encapsulated condition until oviposition, when sperm is totally activated. Sperm cells may remain viable for a long time in the decapsulated state. There was evidence for sperm mixing in the female that remated after oviposition. |
Comparative behavioral and EAG responses of female obliquebanded and redbanded leafroller moths (Lepidoptera: Tortricidae) to their sex pheromone componentsAyhan GÖKÇE, Lukasz L. STELINSKI, Larry J. GUT, Mark E. WHALONEur. J. Entomol. 104 (2): 187-194, 2007 | DOI: 10.14411/eje.2007.029 Studies were conducted investigating the responses of female obliquebanded leafrollers, Choristoneura rosaceana (Harris) and redbanded leafrollers, Argyrotaenia velutinana (Walker) (Lepidoptera: Tortricidae), to components of their sex pheromone. Electroantennogram (EAG) recordings revealed significant responses from antennae of female moths of both species to the major pheromone component, (Z)-11-tetradecenyl acetate, at dosages ranging from 2 µg - 2 mg. However, tested individually, the minor pheromone components of the obliquebanded leafroller, (E)-11-tetradecenyl acetate and (Z)-11-tetradecenol, elicited little or no antennal response from conspecific females. This result was consistent for redbanded leafroller females, which showed only weak responses to the minor component (E)-11-tetradecenyl acetate at a 2 mg dosage. For both species, species-specific blend ratios of the Z and E isomers of tetradecenyl acetate did not elicit a greater antennal response than the Z isomer alone. Virgin females of each species (2-4 d old) were placed into 1-liter plastic assay chambers with constant throughput of carbon-filtered air passed through 1-liter flasks containing rubber septa loaded with (Z)- and (E)-11-tetradecenyl acetates and (Z)-11-tetradecenol for trials with female obliquebanded leafrollers or with (Z)- and (E)-11-tetradecenyl acetates and dodecyl acetate for trials with female redbanded leafrollers. Exposure to pheromone-permeated air delayed the onset of calling by 1 h and terminated the calling period 1 h earlier for both species compared with solvent-control exposed females. Furthermore, the total proportion of calling females was reduced by half in chambers receiving constant throughput of pheromone-permeated air compared with solvent controls. Exposure to pheromone-permeated air also significantly reduced egg-laying in both species compared with clean-air controls. Furthermore, application of the major pheromone component, (Z)-11-tetradecenyl acetate, at dosages ranging from 2 µg - 2 mg to wax-paper ovipositional substrates, deterred oviposition by females of both species. Our data suggest that application of synthetic sex-attractant pheromones for mating disruption of leafroller species may have deleterious effects on female moth behavior, which may contribute to pest control. Field investigations will need to be conducted to test this hypothesis. |
Distribution and diversity of wheat aphid parasitoids (Hymenoptera: Braconidae: Aphidiinae) in IranEhsan RAKHSHANI, ®eljko TOMANOVIÆ, Petr STARÝ, Ali-Asghar TALEBI, Nickolas G. KAVALLIERATOS, Abbas-Ali ZAMANI, Srdjan STAMENKOVIÆEur. J. Entomol. 105 (5): 863-870, 2008 | DOI: 10.14411/eje.2008.114 Eleven species of parasitoids were found to attack 7 species of wheat aphids in Iran. The Simpson's Index of diversity (D) used to compare the aphidiine diversity in various cereal crop systems in geographically different regions of Iran ranged from 0.197 to 0.488, depending on locality. There were significant differences among species diversities at different altitudes. The central highlands (1000-1500 meters above mean sea level) were the areas with the most diverse aphid parasitoid complex, differing significantly from that at lower and higher altitudes. We found that altitude explained about 10% of the cereal aphid parasitoid distribution pattern in Iran. Species of the genus Aphidius Nees were the most abundant and widely distributed. These were Aphidius rhopalosiphi De Stefani, Aphidius uzbekistanicus Luzhetski, Aphidius colemani Viereck and Aphidius matricariae Haliday. A. uzbekistanicus, Ephedrus plagiator (Nees) and Ephedrus persicae Froggat were encountered mainly on the plains at lower altitudes. Diuraphis noxia (Kurdjumov) was mainly recorded at higher altitudes in Iran along with its dominant parasitoid species, Diaeretiella rapae (MIntosh). The fact that Iran is close to the presumed area of D. noxia origin (Central Asian submountains) could be very important in further biological control efforts against this pest aphid. According to our results, Aphidius ervi Haliday is a very rare parasitoid of cereal aphids in Iran, which contrast with its high abundance in Europe and North America. |
Why does the Namib Desert tenebrionid Onymacris unguicularis (Coleoptera: Tenebrionidae) fog-bask?Strinivasan G. NAIDUEur. J. Entomol. 105 (5): 829-838, 2008 | DOI: 10.14411/eje.2008.110 Dehydration of Onymacris unguicularis (Haag) for 10 days at 27°C resulted in a weight loss of 14.9%, and a 37% decrease in haemolymph volume. Although there was an overall decrease in the lipid content during this period, metabolic water production was insufficient to maintain total body water (TBW). Rehydration resulted in increases in body weight (6.2% of initial weight), TBW (to normality), and haemolymph volume (sub-normal at the end of rehydration). Despite an increase of 44.0 mg in the wet weight of O. unguicularis after drinking for 1h, there was little change in the water content at this time, although the total lipid content increased significantly. Increases in haemolymph osmolality, sodium, potassium, chloride, amino acid and total sugar concentrations during dehydration were subject to osmoregulatory control. No evidence of an active amino acid-soluble protein interchange was noted during dehydration or rehydration. Haemolymph trehalose levels were significantly increased at the end of rehydration (relative to immediate pre-rehydration values), indicating de novo sugar synthesis at this time. Osmotic and ionic regulation was evident during rehydration, but control of OP during haemolymph-dilution is poor and accomplished largely by the addition to the haemolymph of free amino acids and solute(s) not measured in this study. There was little mobilization of sodium and chloride ions from storage sites at this time. The lesser osmoregulatory ability of Onymacris unguicularis and perhaps earlier susceptibility to osmotic stress, a significantly high normal blood glycerol level (relative to other diurnal adesmiine tenebrionids), and a water storage mechanism associated with synthesis of fat, probably all contribute to the development of fog-basking behaviour in this species. Water gain in O. unguicularis during periods of relative drought is probably largely accomplished by a greater food consumption. |
Leucopis annulipes larvae (Diptera: Chamaemyiidae) use a furtive predation strategy within aphid coloniesBruno FRÉCHETTE, François LAROUCHE, Éric LUCASEur. J. Entomol. 105 (3): 399-403, 2008 | DOI: 10.14411/eje.2008.050 A laboratory experiment was conducted to determine whether the predation strategy of larvae of the aphidophagous silver fly Leucopis annulipes Zetterstedt (Diptera: Chamaemyiidae) is furtive, as are larvae of the aphidophagous midge Aphidoletes aphidimyza Rondani (Diptera: Cecidomyiidae), or active like aphidophagous ladybird beetle larvae (Coleoptera: Coccinellidae). The impact of L. annulipes larvae on pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), colony disturbance was evaluated and compared with that of the furtive predator A. aphidimyza and the active-searching ladybird beetle Harmonia axyridis Pallas. Results indicate that aphids showed significantly fewer defensive acts (dropping, walking away, wriggling) in the presence of L. annulipes larvae than of ladybird beetle larvae. Furthermore, the impact of L. annulipes larvae on aphid colony disturbance was similar to that of A. aphidimyza and to a control treatment without predators. These results clearly indicate that L. annulipes larvae use a furtive predation strategy. |
Suitability of various prey types for the development of Propylea japonica (Coleoptera: Coccinellidae)Shi-Ze ZHANG, Fan ZHANG, Bao-Zhen HUAEur. J. Entomol. 104 (1): 149-152, 2007 | DOI: 10.14411/eje.2007.021 The relative suitability of three prey organisms, Bemisia tabaci (Gennadius) eggs, B. tabaci nymphs, and Myzus persicae (Sulzer), to the ladybird Propylea japonica (Thunberg) was evaluated under laboratory conditions. The larvae developed fastest when fed M. persicae, and slowest on B. tabaci eggs. When fed M. persicae, all larvae successfully developed into adult with a growth index (i.e., percent pupation/larval period in days) of 13.16 and development rate of 0.096. The longevity of starving adults was 4.7 ± 0.2 days. In contrast, when fed B. tabaci eggs, all larvae survived to the second instars, 56.7% of which survived to the third instars, 13.3% to the fourth instars; only 6.7% of larvae survived to the pupal stage and the pupae developed into abnormal adults that died shortly. When fed B. tabaci nymphs, all larvae survived and successfully developed into adults with a growth index of 10.71 and development rate of 0.083. The adult body mass was greater when larvae fed M. persicae, compared to adults eclosing from larvae fed B. tabaci nymphs. On the basis of these findings, the order of suitability of three prey organisms for P. japonica is M. persicae > B. tabaci nymph > B. tabaci egg. This is the first record that P. japonica can complete its development when feeding exclusively on whitefly nymphs. |
The genetic architecture of extended life span in the seed beetle Acanthoscelides obtectus (Coleoptera: Bruchidae)Darka ©E©LIJA, Nikola TUCIÆEur. J. Entomol. 105 (4): 553-560, 2008 We studied the genetic architecture of the differences in the longevity between lines selected for postponed senescence and a control population of the seed beetle Acanthoscelides obtectus maintained on two hosts. By using lines with increased longevity, which were obtained by selection on natural variation in longevity, we showed that the genetic architecture of seed beetle longevity is complex, with sex-specific effects and variation attributable to many interacting genes, whose expression depend on the host on which the beetles were reared. The nonadditive genetic effects were more strongly expressed when reared on chickpeas, a novel host, than on beans. Outbreeding depression, with respect to longevity, was a consequence of both the intrinsic effect of interactions between genes from different parental sources (disruption of coadapted gene complexes) and the genotype × host interaction (loss of local adaptation). |
Sperm viability in the male accessory testes and female spermathecae of the bumblebee Bombus terrestris (Hymenoptera: Apidae)Michael GREEFF, Paul SCHMID-HEMPELEur. J. Entomol. 105 (5): 849-854, 2008 | DOI: 10.14411/eje.2008.112 In many species sperm competition selects for large ejaculates while females eliminate or disable a high percentage of the spermatozoa in their storage organs in order to control paternity. Therefore, sperm viability is an excellent measure of the reproductive success of both males and females. Here we assess the viability of spermatozoa in males, freshly mated queens and old queens at the end of a colony cycle of the monandrous bumblebee Bombus terrestris. We found that the accessory testes of males contained a significantly lower percentage of dead sperm (i.e. higher average viability) than the spermathecae of both freshly mated and old queens. In each case, however, the percentage of dead spermatozoa was very small. No differences could be detected between sperm viability in freshly mated and old queens. To test for the possible incompatibility of the sperm and the environment provided by female spermathecae males and females either from different geographic regions (north and south of the Alps) or the same region were mated. We did not find any differences between matings of individuals from within or between regions. The mechanism that causes the lower sperm viability in females remains unknown. |
Insects on decomposing carcasses of small rodents in a secondary forest in Southeastern BrazilThiago De Carvalho MORETTI, Odair Benedito RIBEIRO, Patrícia Jacqueline THYSSEN, Daniel Russ SOLISEur. J. Entomol. 105 (4): 691-696, 2008 The decomposition of small carcasses in the open is frequently neglected although it may provide information of forensic importance. This paper describes an experimental study of arthropod species associated with carcasses of mouse, Mus musculus (Linnaeus, 1758) and rat, Rattus norvegicus (Berkenhout, 1769) (Rodentia: Muridae). Four carcasses were left inside iron cages in sunlit and shady areas in a secondary forest in Southeastern Brazil twice a season for four seasons (n = 16 carcasses of each rodent). The carcasses were removed when arthropods ceased to visit them. The visiting and colonizing invertebrates were collected daily and identified. Immatures were also collected and reared in a laboratory for identification. We collected 6,514 arthropods (820 adults and 5,694 juvenile forms) belonging to 53 species from the families Sarcophagidae, Calliphoridae, Muscidae, Fanniidae, Syrphidae, Richardiidae, Sepsidae, Micropezidae, Otitidae, Drosophilidae, Phoridae, Dolichopodidae, Anthomyiidae, Asilidae and Lauxaniidae (Diptera), Formicidae, Ichneumonidae, Encyrtidae and Apidae (Hymenoptera), Staphylinidae (Coleoptera) and Gonyleptidae (Opiliones). Lucilia eximia (Wiedemann, 1819) (Diptera: Calliphoridae) and Peckia (Pattonella) intermutans (Walker, 1861) (Diptera: Sarcophagidae) deserve special attention because both adult and immature forms were collected in all seasons and in both areas. Our results indicate that the frequency of occurrence of these arthropods was positively associated with carcass size (mouse or rat); no marked insect succession on the carcasses occurred; and the diversity of Calliphoridae and Sarcophagidae was high, irrespective of season. |
Cytogeography of three parallel Robertsonian polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)Pablo César COLOMBOEur. J. Entomol. 105 (1): 59-64, 2008 | DOI: 10.14411/eje.2008.008 C. aquaticum (Acrididae: Leptysminae) inhabits water-hyacinths in the Neotropical region. The blue-flowered water-hyacinth, Eichhornia crassipes, has been introduced elsewhere without its natural enemies and has become a weed; recently C. aquaticum was considered as a possible biological control agent. In this work, six populations were sampled and cytologically studied. C. aquaticum has 2n = 23 chromosomes in males and 24 in females, with an X0/XX sex determination system. All chromosomes are acro-telocentric and the basic karyotype includes three Robertsonian (Rb) translocations between pairs 1/6, 2/5, and 3/4. These polymorphisms are restricted to the lower course of the Paraná river, between Rosario and Buenos Aires. Fusion frequencies increase southwards, thus showing a geographical cline. The polymorphisms mostly accord with Hardy-Weinberg and gametic phase equilibria. The rearrangements cause a drastic chiasma repatterning in the fusion bivalents (or trivalents) which reduces the proximal chiasma frequency. Recombination is also reduced due to the loss of independent segregation. A recombination index that takes into account both these factors correlates negatively with the number of pairs of chromosomes affected by fusions among populations, which does not accord with the "central-marginal" pattern. |
Diapause, cold hardiness and flight ability of Cry1Ac-resistant and -susceptible strains of Helicoverpa armigera (Lepidoptera: Noctuidae)Ge-Mei LIANG, Kong-Ming WU, Brian RECTOR, Yu-Yuan GUOEur. J. Entomol. 104 (4): 699-704, 2007 | DOI: 10.14411/eje.2007.088 The diapause inducement condition, cold hardiness, and flight ability in Cry1Ac-resistant (BtR) and Cry1Ac-susceptible (96S) strains of Helicoverpa armigera (Hübner) were compared in the laboratory. The BtR strain was derived from the 96S strain and shows 1375-fold resistance to the Cry1Ac toxin after having been selected for 52 generations. Compared with the 96S strain, the Bt-resistant strain was more likely to go into diapause under a short-photoperiod environment. At 11L : 13D, 12L : 12D and 13L : 11D photoperiods, the percentages of BtR insects entering diapause were 72.7%, 82.9% and 68.7%, respectively, which were significantly higher than those in the 96S strain (58.6%, 67.4% and 46.3%, respectively) under the same conditions. The supercooling points (SCP) and freezing points (FP) were not significantly different between the BtR and 96S strains. The LT50 (50% lethal time) and LT90 (90% lethal time) of BtR pupae were also not significantly different from those of the 96S strain at -15°C. The moths from both strains had similar flight ability when their larvae were fed with nontoxic control diet. However, the total flight distance of these BtR moths was 56.2 km whose larvae fed on normal diet, which was more than twice as much as for those feeding on Bt diet (26.2 km). Flight duration for these BtR moths was longer after feeding on normal diet (11.6 h) than after feeding on Bt diet (7.3 h). |
Phytophagous insects of giant hogweed Heracleum mantegazzianum (Apiaceae) in invaded areas of Europe and in its native area of the CaucasusSteen Ole HANSEN, Jan HATTENDORF, Ruediger WITTENBERG, Sergey Ya. REZNIK, Charlotte NIELSEN, Hans Peter RAVN, Wolfgang NENTWIGEur. J. Entomol. 103 (2): 387-395, 2006 | DOI: 10.14411/eje.2006.052 Giant hogweed, Heracleum mantegazzianum (Apiaceae), was introduced from the Caucasus into Western Europe more than 150 years ago and later became an invasive weed which created major problems for European authorities. Phytophagous insects were collected in the native range of the giant hogweed (Caucasus) and were compared to those found on plants in the invaded parts of Europe. The list of herbivores was compiled from surveys of 27 localities in nine countries during two seasons. In addition, literature records for herbivores were analysed for a total of 16 Heracleum species. We recorded a total of 265 herbivorous insects on Heracleum species and we analysed them to describe the herbivore assemblages, locate vacant niches, and identify the most host-specific herbivores on H. mantegazzianum. When combining our investigations with similar studies of herbivores on other invasive weeds, all studies show a higher proportion of specialist herbivores in the native habitats compared to the invaded areas, supporting the "enemy release hypothesis" (ERH). When analysing the relative size of the niches (measured as plant organ biomass), we found less herbivore species per biomass on the stem and roots, and more on the leaves (Fig. 5). Most herbivores were polyphagous generalists, some were found to be oligophagous (feeding within the same family of host plants) and a few had only Heracleum species as host plants (monophagous). None were known to feed exclusively on H. mantegazzianum. The oligophagous herbivores were restricted to a few taxonomic groups, especially within the Hemiptera, and were particularly abundant on this weed. |
Effect of insect-resistant transgenic maize on growth and development, utilization of nutrients and in vivo activity of the detoxification enzymes of the Asian corn borer, Ostrinia furnacalis (Lepidoptera: Pyralidae)Min Juan SHI, Pei LING LU, Xiao Li SHI, Yi Zhong YANGEur. J. Entomol. 108 (4): 547-552, 2011 | DOI: 10.14411/eje.2011.070 There is little systematic research on the effect of transgenic maize expressing Bacillus thuringiensis (Bt) toxins on insect survival and the response in vivo of their detoxification enzymes. Results of laboratory bioassays indicate that the whorl leaves of transgenic maize lines G03-2396 and G03-2739 significantly affected the survival of neonate and third instar larvae of the Asian corn borer, Ostrinia furnacalis (Güenée). Neonate mortality two days after being fed on G03-2739 was 72.5% and exceeded 92.5% four days later. The percentage mortality of third instar larvae six days after being fed whorl leaves from G03-2396 exceeded 65%. The resistance of whorl leaves to insect attack was greater than that of maize-ears, but less effective against attacks by third instar larvae. Neonate development was more prolonged when they were fed on whorl leaves of both the transgenic maize lines. In contrast, low pupation (<80% of that recorded in the controls), ecolosion and fecundity were recorded following ingestion of maize-ears, with pupal weights 10-14 mg lower than that of controls. The growth rates of third instar larvae recorded three and six days after feeding on whorl leaves were lower, but food utilization, conversion and relative metabolism were not significantly affected. Relative food ingestion, relative growth rate and other nutritional indicators of third instar larvae were significantly lower six days after the ingestion of ears and that of fifth instar larvae after three days. In vivo activity of carboxylesterase was decreased to a greater degree after three days when the larvae were fed on whorl leaves than ears, with no significant effect on fifth instar larvae. Furthermore, in vivo activity of glutathione S-transferase (GST) of third instar larvae was significantly affected following the ingestion of whorl leaves. These results are discussed in the context of the literature on the resistance of transgenic plants and of improving the resistance of plants to attack by the different larval stages of insects. |
Variation in the colour of the necrophagous fly, Prochyliza nigrimana (Diptera: Piophilidae): A case of seasonal polymorphismDaniel MARTÍN-VEGA, Arturo BAZEur. J. Entomol. 108 (2): 231-234, 2011 | DOI: 10.14411/eje.2011.031 The occurrence of colour polymorphism in wild populations of the necrophagous fly Prochyliza nigrimana (Diptera: Piophilidae) is recorded but never treated in detail. The present paper shows that there is a seasonal distribution in the morphotypes, with the dark morphs emerging in spring and pale morphs emerging later and most abundant in summer. Furthermore, different proportions of each morph occur along altitudinal gradients, with dark morphs significantly more abundant at low altitudes, where mean temperatures are warmer than at high altitudes where the pale coloured morphs were more abundant. Explanations based on the adaptive value of thermal melanism are discussed. |
Contribution to the biochemical characterization of the silk and structure characterization of the cocoons of the horse chestnut leaf miner Cameraria ohridella (Lepidoptera: Gracillariidae)Veronika HNÌVSOVÁ, Dalibor KODRÍK, Franti¹ek WEYDAEur. J. Entomol. 108 (4): 711-715, 2011 | DOI: 10.14411/eje.2011.091 This study of the proteins in the silk of the summer and winter cocoons of the horse chestnut leaf miner Cameraria ohridella revealed they can inhibit protease activity. The inhibitory activity of the summer silk was higher against both the fungal proteinase K and bacterial subtilisin than that of the winter silk. Also, the winter silk was more effective in inhibiting proteinase K than subtilisin. Further, it was demonstrated that some of the silk proteins are glycosylated probably by mannose carbohydrates. An electron microscopy study of the cocoons revealed the presence of silk fibres with different diameters in some pupal chambers. |
The diversity of phoretic Mesostigmata on Ips typographus (Coleoptera: Scolytinae) caught in the Karkonosze forestDariusz J. GWIAZDOWICZ, Jacek KAMCZYC, Jerzy BLOSZYKEur. J. Entomol. 108 (3): 489-491, 2011 This study determined the scale of the phoresy of mesostigmatid mite by Ips typographus. Thirty pheromone traps in the Karkonosze National Park (Poland) caught 10,575 bark beetles on which there were 2,388 mesostigmatid mites belonging to eight species. The most numerous mites were Dendrolaelaps quadrisetus (1076 ind.) and Trichouropoda polytricha (1067 ind.). |
Aproceros leucopoda (Hymenoptera: Argidae): An East Asian pest of elms (Ulmus spp.) invading EuropeStephan M. BLANK, Hideho HARA, József MIKULÁS, György CSÓKA, Constantin CIORNEI, Raoul CONSTANTINEANU, Irinel CONSTANTINEANU, Ladislav ROLLER, Ewald ALTENHOFER, Tomasz HUFLEJT, Gábor VÉTEKEur. J. Entomol. 107 (3): 357-367, 2010 | DOI: 10.14411/eje.2010.045 An invasive sawfly Aproceros leucopoda Takeuchi, 1939, which originates from East Asia, has colonized elms (Ulmus spp.) in Austria, Hungary, Poland, Romania, Slovakia and the Ukraine, at least since 2003. In Europe, the larvae can completely defoliate native and non-native elm trees and may cause at least partial dieback. Field observations indicate that elms are infested independent of their age and site characteristics. The life cycle of A. leucopoda is described based on material reared in Hokkaido, Japan. Parthenogenetic reproduction, short life cycle of summer generations and the ability to produce four generations per year result in the production of numerous progeny. The evolution of a seasonal dimorphism in head morphology, a simple cocoon that is attached directly to the host plant and a short period spent in the cocoon stage during summer, are putative apomorphies shared by Aproceros Takeuchi, 1939 and Aprosthema Konow, 1899. These traits reduce developmental costs and contribute to the proliferation of A. leucopoda. No specialized parasitoid, that can effectively reduce outbreaks of this species, is known. It is likely that this pest will spread into central and south-western Europe. Further monitoring of A. leucopoda is required to assess future range extensions in Europe, its exacerbating effect on Dutch elm disease and to find a suitable biocontrol agent. Concise keys to imaginal and larval stages are presented that will facilitate the identification of A. leucopoda. |
Butterflies (Lepidoptera) highlight the ecological value of shrubland and grassland mosaics in Cypriot garrigue ecosystemsÖzge ÖZDEN, David J. HODGSONEur. J. Entomol. 108 (3): 431-437, 2011 We used butterfly assemblages to evaluate the ecological value of habitat mosaics within garrigue ecosystems in Cyprus. To understand the importance of the local plant communities for Cypriot butterflies, five plots in each of two habitat types (grass-dominated or shrub-dominated) were surveyed weekly for a period of five months in order to assess the abundance, species richness and diversity of butterflies. A total of 810 butterflies of 16 species were recorded. Indices of butterfly diversity, calculated across the whole season, were similar between grassland and shrubland dominated mosaics. However, species richness of all butterflies was consistently higher in grassland dominated mosaics throughout the whole season. The peak abundance of all butterfly species occurred during mid-season (late April - early May), with similar numbers observed in both habitat types. However, a greater abundance was observed during early and late season in grassland patches. The abundance of endemic species (Maniola cypricola, Hipparchia cypriensis, Glaucopsyche paphos) peaked earlier in the season in shrubland patches, but was higher in grassland patches in late season. This difference in seasonal timing of endemic abundance was dominated by the seasonal dynamics of M. cypricola. These results suggest that, while garrigue is characterised by its shrub flora, management to maintain a mosaic of grassland and shrubland could act to maximise the abundance and richness of indicator species groups of conservation importance. |
Molecular phylogenetic analysis of a scale insect (Drosicha mangiferae; Hemiptera: Monophlebidae) infesting mango orchards in PakistanMuhammad ASHFAQ, Jehan ARA, Ali Raza NOOR, Paul D.N. HEBERT, Shahid MANSOOREur. J. Entomol. 108 (4): 553-559, 2011 | DOI: 10.14411/eje.2011.071 Mango orchards in Pakistan are attacked by the scale insect, Drosicha mangiferae (Hemiptera: Monophlebidae), commonly called the "mango mealybug". This insect is univoltine, active from December through May and targets multiple host plants. We used DNA nucleotide sequences to characterize and determine the phylogenetic status of D. mangiferae. Mango mealybugs were collected from several tree species from different localities and patterns of phylogenetic and genetic diversity were examined at both nuclear (18S, ITS1) and mitochondrial (COI) genes. Phylogenetic analysis confirms that the mango mealybug belongs to the family Monophlebidae. Minor genetic differences in both the ITS1 and the COI barcode region were noted among D. mangiferae collected from different geographic localities. These genetic differences revealed the existence of two genotypes of D. mangiferae that are region specific but not host-specific. |
Host recognition and acceptance behaviour in Cotesia sesamiae and C. flavipes (Hymenoptera: Braconidae), parasitoids of gramineous stemborers in AfricaMeshack OBONYO, Fritz SCHULTHESS, Bruno LE RU, Johnnie VAN DEN BERG, Paul-André CALATAYUDEur. J. Entomol. 107 (2): 169-176, 2010 | DOI: 10.14411/eje.2010.022 The host recognition and acceptance behaviour of two braconid larval parasitoids (Cotesia sesamiae and C. flavipes) were studied using natural stemborer hosts (i.e., the noctuid Busseola fusca for C. sesamiae, and the crambid Chilo partellus for C. flavipes) and a non-host (the pyralid Eldana saccharina). A single larva was introduced into an arena together with a female parasitoid and the behaviour of the wasp recorded until it either stung the larva or for a maximum of 5 min if it did not sting the larva. There was a clear hierarchy of behavioural steps, which was similar for both parasitoid species. In the presence of suitable host larvae, after a latency period of 16-17 s, the wasp walked rapidly drumming the surface with its antennae until it located the larva. After location and antennal examination of the host, which lasted 60-70 s and 30 s, respectively, the parasitoid inserted its ovipositor. Stinging that resulted in successful oviposition usually lasted 5-6 s. In the presence of non-host larvae, the latency period was between 25-70 s, and parasitoids spent significantly more time walking and antennal drumming on larvae without ovipositing. It is likely that these two parasitoid species use their antennae for host recognition, and both their antennae and tarsi for final acceptance of a host for oviposition. In both C. sesamiae and C. flavipes tactile and contact-chemoreception stimuli from the hosts seemed to play a major role in the decision to oviposit. |
Comparative analysis of the testes and spermatogenesis in species of the family Pentatomidae (Heteroptera)Hederson Vinícius De SOUZA, Aline Sumitani MURAKAMI, Juliana De MOURA, Elisângela Cristiane De ALMEIDA, Inaiá Fernandes Gallego MARQUES, Mary Massumi ITOYAMAEur. J. Entomol. 108 (3): 333-345, 2011 There are few studies on the morphology and meiosis in the testicles of Heteroptera, but are extremely important, especially for the family Pentatomidae, because in some species in this family meiosis in the testicular lobes results in the production of non-fertile spermatozoa. With the aim of improving the level of understanding of this phenomenon the morphology of the testes and spermatogenesis in 10 species of Pentatomidae were recorded and compared. All of them have testes covered by a pigmented peritoneal sheath. In some species the internal membrane or just inside the peritoneal sheath is pigmented. The pigmentation of both membranes varied. The pigmentation of both was either yellow, or the internal membrane was yellowish and the external one reddish. When the membrane is pigmented, the colour is red or yellow. The number of lobes varied from 3 to 7, with intermediate numbers of 4 and 6. The size and diameter of the lobes are similar in all the species studied, except Proxys albopunculatus, in which the diameter of the third and fifth is smaller than that of the other lobes. The behaviour of the cells during spermatogenesis was the same in all lobes of most species, except in P. albopunctulatus, in which the harlequin lobe is absent and the cells in lobes 4 and 6 exhibited characteristics different from those of cells in lobes 1-3 and 5. Chlorocoris complanatus and Loxa deducta (both Pentatominae) have a harlequin lobe (lobe 5). The chromosome complements recorded were: 2n = 12 (10A + XY) in Dichelops melacanthus and Edessa collaris, 2n = 14 (12A + XY) in C. complanatus, Edessa meditabunda, Ladeaschistus sp., Loxa deducta, P. albopunctulatus, Piezodorus guildinii and Thyanta perditor and 2n = 16 (14A + XY) in Edessa affinis. Thus, this study extends the knowledge of characteristics, such as the pigmentation of the peritoneal sheath, number of testicular lobes, the occurrence of meiotic cells in some testicular lobes, and the chromosome complements of the family Pentatomidae. |
Insertion of miniature subterminal inverted repeat-like elements in diapause-regulated genes in the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)George D. YOCUM, Michelle J. TOUTGES, Richard L. ROEHRDANZ, Preston J. DIHLEEur. J. Entomol. 108 (2): 197-203, 2011 | DOI: 10.14411/eje.2011.027 Determining the genomic structure of diapause-associated transcripts (DAT) -2 and -3 led to the isolation of four novel miniature subterminal inverted repeat-like elements (MSITE): Mild-1, -2, -3 and -4. Mild-1a is inserted within the first intron of diapause protein-1. Mild-1a is 284 bp in length, has a 14 bp target site duplication and three sets of subterminal inverted repeats. The second element, Mild-2a, is inserted within the 3' terminus of Mild-1a. Mild-2a is 29 bp long with a 3 bp target site duplication and one set of subterminal inverted repeats. Using primers based on Mild-1, genomic clones were developed leading to the isolation of Mild-3a. Mild-3a shares 60% identity with Mild-1a, is 253 bp long, has a 9 bp target site duplication and has one set of subterminal inverted repeats. Mild-4a is inserted within the first intron of DAT-2 and is 227 bp in length with a 12 bp target site duplication. Mild-4a appears to be an intermediate form between a miniature inverted repeat transposable element (MITE) and a MSITE because the 5' inverted repeat is terminal (i.e., adjacent to the target site duplication) as in MITEs, but the 3' inverted repeat is separated (in this case, by 33 bp) from the 3' target site duplication as in MSITEs. The target site duplications of Mild-1, -3 and -4 families share a common conserved core of AATTT. All of the transposable elements are AT rich and are able to form hairpin structures. Within the promoter region of DAT-3 is a 163 bp sequence (Mild-1b) that shares 77% identity to the 3' terminus of Mild-1a. Mild-4a has identity to 25 and 53 bp regions within the promoter of the juvenile hormone esterase B gene. Southern blot analysis revealed the presence of Mild-1 and -3 elements in both Leptinotarsa decemlineata and Leptinotarsa juncta indicating that these elements are ancestral to the L. decemlineata, L. juncta separation. |
Weather factors affecting the male mate-locating tactics of the small copper butterfly (Lepidoptera: Lycaenidae)Jun-Ya IDEEur. J. Entomol. 107 (3): 369-376, 2010 | DOI: 10.14411/eje.2010.046 Males of the small copper butterfly, Lycaena phlaeas daimio, exhibit two mate-locating tactics: patrolling and perching. Field investigations were conducted to determine the biotic and abiotic factors affecting the mate-locating behaviour of male L. phlaeas. Patrolling was often observed when light intensity was high. Perching was performed throughout the day regardless of environmental conditions, but the chasing of passing insects increased at high light intensities. The activity patterns of the males were not affected by those of the females. The thoracic temperatures of patrolling males were lower than those of perching males under cool conditions, suggesting that patrolling males lose heat more easily. In contrast, perching males may more easily regulate their body temperature to a suitable level as they fly for shorter periods and can bask while waiting for mates. These results highlight several reasons (i.e., heat loss, energetic costs) why males patrol when weather conditions are favourable. |
Methoprene modifies adipokinetic hormone characteristics in the firebug Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae)Dalibor KODRÍK, Glenda ALQUICER, Radomír SOCHAEur. J. Entomol. 107 (1): 33-39, 2010 | DOI: 10.14411/eje.2010.003 In the present study the hypothesis that there is a feedback between juvenile hormone and adipokinetic hormones (AKHs) was investigated by topical application of the juvenoid methoprene on 9-day-old adult males of the firebug Pyrrhocoris apterus. This juvenoid (2 µg) induced a significant reduction of haemolymph lipids 24 h after treatment; however, it did not significantly reduce the ability of Pyrap-AKH (10 pmol/bug) to mobilize fat body lipids 6-72 h after the methoprene application. The same methoprene treatment elicited a significant increase of AKH content in the CNS (central nervous system: brain + corpora cardiaca + corpora allata) of experimental males 24 and 48 h after the juvenoid application. A significant decrease in the AKH level in the haemolymph was recorded at the same times and under the same experimental conditions. Similar results were observed when production of the AKHs from the CNS of topically treated males was measured under in vitro conditions. It is suggested that methoprene may reduce AKH release from the CNS resulting in an increase in the AKH content of the CNS due to accumulation rather than stimulation of AKH synthesis. Possible consequences of this phenomenon on the physiology of P. apterus are discussed. |
Spatial distributions of European clearwing moths (Lepidoptera: Sesiidae)Werner ULRICH, Marek B¡KOWSKI, Zdenìk LA©TÙVKAEur. J. Entomol. 108 (3): 439-446, 2011 Although the sizes of the geographical ranges of plant and animal species are of major interest to macroecologists, the spatial distributions and environmental correlates of only a small group of animals and plants are well studied. Here data on the spatial distributions of 116 European clearwing moths (Sesiidae) was used to determine the patterns in spatial distribution, postglacial colonization and endemism. The spatial distributions of sesiids are significantly more coherent and there are fewer isolated occurrences and unexpected absences than predicted by a random sample null model. After correcting for environmental correlates, islands and mainland countries did not differ significantly in the number of species with small ranges. Polyphagous wood attending species were more widespread than those with other life histories. Species of Siberian origin had wider ranges than those of Mediterranean origin. Nestedness and species co-occurrence analysis did not support a unidirectional postglacial colonization from a Southern European refuge but colonization from both Southern and Eastern Europe. |
Ground-dwelling arthropod communities present in three types of Cantabrian (NW Spain) heathland grazed by sheep or goatsRocío ROSA GARCÍA, Francisco J. OCHARAN, Berta M. JÁUREGUI, Urcesino GARCÍA, Koldo OSORO, Rafael CELAYAEur. J. Entomol. 107 (2): 219-227, 2010 | DOI: 10.14411/eje.2010.029 The abundance, diversity and community composition of ground-dwelling arthropods present in three different types of Cantabrian heathland grazed by small ruminants were studied. A factorial design of three vegetation types (heather-, gorse- or grass-dominated) and two grazer species (sheep or goats) with two replicates was established in twelve 0.6 ha paddocks. Ground-dwelling arthropods (Araneae, Opiliones, Isopoda, Julida, Microcoryphia, Hemiptera, Coleoptera and Hymenoptera) were recorded using pitfall traps and plant cover and canopy height assessed in each paddock in 2005, 2006 and 2007. Higher abundances and more families of ground dwelling arthropods were recorded in areas dominated by heather, although certain species were more numerous in areas dominated by grass. The direct effects of the grazer species on arthropods were subtle compared to their great effect on the vegetation. Significant interactions between grazer species and vegetation were observed for some taxa and the overall arthropod community composition. Gradient analyses indicate that arthropod assemblages that include Lycosidae, Opiliones and Carabidae differed between vegetation types and years, but are not affected by the grazer species. Our study shows that areas dominated by shrubby and diverse heather had the highest diversity and abundance of arthropods. Species composition varied along a gradient in the structure of the vegetation, which in turn was modified by the grazer species. |
Two ways of finding a host: A specialist and a generalist parasitoid species (Hymenoptera: Chalcidoidea: Pteromalidae)Ralph S. PETERSEur. J. Entomol. 108 (4): 565-573, 2011 | DOI: 10.14411/eje.2011.073 Two closely related parasitoid wasp species with different host specificities were used for experimental studies on the biology of host finding, a crucial element of parasitoid life history: The habitat and host specialist Nasonia vitripennis and the habitat and host generalist Dibrachys microgastri (Chalcidoidea: Pteromalidae). The host finding parameters tested included reaction to olfactory cues, aspects of locomotor activity, ability to locate hidden hosts and day-night-activity. The results revealed distinct interspecific differences that match the respective host and habitat ranges of the two species. In N. vitripennis host finding is dominated by olfactory reaction to hosts and host habitat, i.e., fly puparia and birds' nests. In D. microgastri olfactory cues have only a minor role. Its host finding is characterized by rapid searching at random. Both species are able to locate hidden hosts. Although still incomplete, these insights into host finding by two parasitoid species with different life history strategies indicate they can be characterized by specific combinations of behavioural host finding features. |
Functional responses of immature stages of Propylea quatuordecimpunctata (Coleoptera: Coccinellidae) to Aphis fabae (Hemiptera: Aphididae)Nickolaos E. PAPANIKOLAOU, Angeliki F. MARTINOU, Dimitrios C. KONTODIMAS, Yiannis G. MATSINOS, Panagiotis G. MILONASEur. J. Entomol. 108 (3): 391-395, 2011 Functional responses of immature stages of Propylea quatuordecimpunctata (L.) to varying densities of Aphis fabae Scopoli reared on Vicia faba L. were evaluated under laboratory conditions. All larval stages of the predator were starved for 12 h prior to being placed individually for 24 h in plastic containers with different densities of its prey, A. fabae, on potted V. faba plants. Logistic regression analysis of the proportion of aphids consumed as a function of initial density indicated that all larval instars of P. quatuordecimpunctata exhibited a type II functional response when searching for A. fabae on V. faba plants. Attack rates (0.059, 0.057, 0.065 and 0.064) and handling times (6.18, 2.37, 1.06 and 0.44) for first to fourth instar larvae, respectively, were estimated using Holling's disc equation. |
The quality of aphids as food for generalist predators: implications for natural control of aphidsSøren TOFTEur. J. Entomol. 102 (3): 371-383, 2005 | DOI: 10.14411/eje.2005.054 The paper reviews existing data on the food quality of cereal aphids for generalist predators. Data are presented for spiders, harvestmen, carabid and staphylinid beetles, cockroaches, ants and one species of bird. All results agree that cereal aphids are low-quality food compared to alternative prey types (in most studies fruit flies). This is associated both with a low consumption capacity for aphids and a low utilization efficiency of the aphid food. A pure aphid diet allows full juvenile development in only a few species. Aphids as part of mixed diets can have negative, neutral or positive effects, which depends on the quality of the remaining diet. The low consumption capacity for aphids is due to the development of a specific feeding aversion. Genetic variation in the ability to tolerate aphids has been documented, indicating that predators may be able to adapt to a higher proportion of aphids in the diet in areas where outbreaks are frequent. A consequence of these findings is that predator populations rely on alternative prey (e.g. Collembola and Diptera) for maintenance and reproduction, and are probably unable to benefit nutritionally from an aphid outbreak. The low food quality of aphids to generalist predators explains why generalist and specialist predators have widely different roles in aphid biocontrol, but does not rule out that under some conditions the generalists may be able to inhibit aphid population growth sufficiently to prevent an outbreak, as field experiments have indicated. Simulation modelling shows that a low consumption capacity for aphids has little influence on the ability to prevent aphid population increase at low aphid immigration rates, but a great influence at high aphid immigration rates. Modelling also indicates that there may be an optimal availability of high-quality alternative prey that maximizes the impact of generalist predators on aphid population growth. |



