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Suction sampling of grassland invertebrates using the G-vac: Quantifying and avoiding peripheral suction effectsAndrew CHERRILLEur. J. Entomol. 112 (3): 520-524, 2015 | DOI: 10.14411/eje.2015.058 Abstract. Suction sampling with modified garden leaf-blowers (G-vacs) is a widely used method for research on invertebrates in agricultural and grassland habitats. Approaches vary from sweeping the collecting nozzle across the surface of the vegetation within a known area, applying the nozzle firmly to the ground to delimit a sample area equal to nozzle crosssection, or applying the nozzle repeatedly within a larger open-ended cylinder placed on the ground. These approaches vary in potential for the inadvertent capture of specimens from outside of the sample area as a result of air being drawn into the nozzle from adjacent vegetation. This has never been studied adequately and is defined here for the first time as the Peripheral Suction Effect (PSE). Invertebrate species are likely to differ in susceptibility to PSE and so both sample size and composition could be impacted. This study compares two series of samples of Auchenorrhyncha taken using the same G-vac suction sampler (nozzle area, 0.01 m2) from areas enclosed and unenclosed by an open-ended cylindrical enclosure (area 0.17 m2) intended to prevent PSE. The unenclosed samples contained greater numbers of leafhoppers including Arthaldeus pascuellus, Javesella pellucida and immature Deltocephalinae. Numbers of immature Delphacinae did not differ between enclosed and unenclosed samples. The species composition of the two series of samples was similar, but the proportional representation of immature Delphacinae in unenclosed samples was diluted by the inflated numbers of other taxa that were drawn from the surrounding area. Peripheral suction effects are taxa-specific and therefore have the potential to bias measures of invertebrate community composition. Use of an open-ended cylinder to delimit the sample area is recommended as a simple, inexpensive and effective method of avoiding problems associated with PSE when using a G-vac. The potential for PSE with other models of suction samplers is discussed and questions for further research are identified. |
Epitrix papa sp. n. (Coleoptera: Chrysomelidae: Galerucinae: Alticini), previously misidentified as Epitrix similaris, is a threat to potato production in EuropeMarina J. ORLOVA-BIENKOWSKAJAEur. J. Entomol. 112 (4): 824-830, 2015 | DOI: 10.14411/eje.2015.096 A nonnative pest of potato recently established and causing significant economic damage in Portugal and Spain was initially identified as Epitrix similaris Gentner and included on lists of quarantine pests. The identity of this pest was doubted by some experts, since E. similaris is a rare species previously recorded only from California and does not damage potato in its native range. Our comparison of 20 specimens of this pest from Portugal with paratypes of E. similaris has revealed that it is not E. similaris. The name "Epitrix similaris" should be removed from lists of quarantine pests. The damage to potato tubers caused by the larvae of this pest is similar to that of E. tuberis Gentner, but examination of paratypes of E. tuberis has revealed that the pest is not E. tuberis. This pest differs from all species of Epitrix recorded in the Holarctic and from all known Epitrix pests of potato in the world. Herewith it is described as a new species Epitrix papa sp. n., whose native range is unknown. |
Aphid honeydew: An arrestant and a contact kairomone for Episyrphus balteatus (Diptera: Syrphidae) larvae and adultsPascal D. LEROY, Raki ALMOHAMAD, Sabrine ATTIA, Quentin CAPELLA, François J. VERHEGGEN, Eric HAUBRUGE, Frédéric FRANCISEur. J. Entomol. 111 (2): 237-242, 2014 | DOI: 10.14411/eje.2014.028 Predator searching efficiency increases in response to a variety of environmental cues associated with its prey. The sugary excretion of aphids (honeydew) has been found to act as a prey-associated cue for many aphid natural enemies. In the present study, the honeydew excreted by Acyrthosiphon pisum (Harris) was identified as an arrestant and a contact kairomone for young larvae and adults of a common predatory hoverfly, Episyrphus balteatus (De Geer) (Diptera: Syrphidae). First and second instar larvae increased their foraging behaviour in the honeydew-treated area. When plants were sprayed with crude honeydew, the speed of movement of female E. balteatus was significantly higher than in controls, resulting in a longer period of time spent on treated plants and laying eggs. We conclude that the honeydew excreted by A. pisum induces searching behaviour and acts as and arrestant not only for adults but also for young E. balteatus larvae. |
Cryptic diversity and signs of mitochondrial introgression in the Agrilus viridis species complex (Coleoptera: Buprestidae)Mikko PENTINSAARI, Marko MUTANEN, Lauri KAILAEur. J. Entomol. 111 (4): 475-486, 2014 | DOI: 10.14411/eje.2014.072 The jewel beetle genus Agrilus (Buprestidae), with approximately 2880 recognized species, is taxonomically challenging due to the great similarity of species. An example of taxonomic ambiguity is the Agrilus viridis species group, particularly the viridis complex that comprises many varieties differing both ecologically and morphologically. The status of these varieties has remained largely unresolved and no consensus exists on their status. We used geometric morphometrics in combination with the DNA barcode marker sequence in order to evaluate the possible distinction among populations of A. viridis feeding on Alnus, Betula and a variety of Salix species in Finland. We found that morphology supports the existence of two species, one feeding on Betula and Alnus, the other feeding on Salix. The findings based on DNA barcodes are more complex, suggesting possible introgression events in the species' history. Our results suggest that the Betula/Alnus and Salix feeding forms of A. viridis represent distinct species that have, while maintaining their morphological integrity, probably experienced repeated hybridization events in the past. DNA barcoding provides valuable additional information for taxonomic studies based on careful morphological study and information on their ecology, but drawing taxonomic conclusions from barcode data alone can lead to considerable confusion. |
Effects of environmental factors on the regulation of egg diapause in the walking-stick insect, Ramulus irregulariterdentatus (Phasmatodea: Phasmatidae)Hiroyuki YAMAGUCHI, Keiji NAKAMURAEur. J. Entomol. 112 (1): 35-40, 2015 | DOI: 10.14411/eje.2015.011 Environmental factors that regulate egg diapause in the walking-stick insect, Ramulus irregulariterdentatus, were studied. Insects collected in fields at Okayama, Japan soon after hatching in spring were reared under constant laboratory conditions. After adult emergence, their eggs were placed outdoors or incubated under constant laboratory conditions. Most eggs kept at 15 or 20°C hatched more than 100 days after oviposition. At 25°C, however, many eggs remained in diapause throughout the experimental period although a small number hatched slightly earlier than those kept at the lower temperature. The maternal photoperiod affected the egg period at 20 and 25°C; eggs from females reared under short day conditions hatched significantly earlier. A low temperature of 10°C shortens diapause development, whereas 5°C did not have a clear effect on time to hatching. When eggs of females reared under long day conditions were placed outdoors from June to early July, most hatched the next spring. On the other hand, eggs of females reared under short day conditions hatched before winter if they were laid before mid-July. The short day eggs laid in August and September hatched successfully the following April, and there was a positive correlation between the date of oviposition and time of hatching. It is concluded that low temperatures in mid-winter do not terminate diapause development. The results revealed that both maternal regulation of diapause intensity and the rate of diapause development play an important role in maintaining a monovoltine life cycle in Ramulus irregulariterdentatus. |
An optimized method for mass rearing the tiger-fly, Coenosia attenuata (Diptera: Muscidae)Joana MARTINS, Célia MATEUS, Ana C. RAMOS, Elisabete FIGUEIREDOEur. J. Entomol. 112 (3): 470-476, 2015 | DOI: 10.14411/eje.2015.059 The tiger-fly Coenosia attenuata Stein (Diptera: Muscidae) is a predator that is currently thought to be a useful biological control agent in greenhouses, especially in the Mediterranean region. Here, we present a method for rearing this predator in the laboratory by feeding it on fungus gnats (fed on Pleurotus ostreatus fungus) and drosophilids (Diptera). Over the past two years, this method has been continuously used to successfully produce predators for bioecological studies in the laboratory. Rearing cages with one, five or 10 male-female pairs, either of laboratory or field origin, were compared using females that were either unmated and recently emerged, or mated and about 20 days old (post-emergence). We evaluated the following parameters: number of rearing cages in which adults emerged, number and sex ratio of emerged adults, period from the introduction of parental pairs into cages and the emergence of the first offspring adults, and the period over which emergence occurred in the cages. Based on our results and in order to minimize the space needed for the colony, cages should be stocked with ca. 10 parental pairs, either of field or laboratory origin, with at least some mated females about 20 days post emergence. We also found that the predator's rearing substrate in the cages is improved if coconut fibre is mixed with the soil. These findings will improve the efficiency of C. attenuata rearing, an important step if it is to be used as a biological control agent. |
Monitoring of Matsucoccus feytaudi (Hemiptera: Matsucoccidae) and its natural enemies in Spain using sticky tapes and pheromone trapsEugenia RODRIGO, Marta CATALÁ-OLTRA, Eduardo PÉREZ-LAORGA, Manuel BAENAEur. J. Entomol. 110 (2): 301-310, 2013 | DOI: 10.14411/eje.2013.043 The maritime pine bast scale, Matsucoccus feytaudi Ducasse (Hemiptera: Matsucoccidae), occurs in the western part of the Mediterranean basin and is a sap sucking insect that feeds only on maritime pine (Pinus pinaster Aiton). It causes damage in SE France and Italy, where it was accidentally introduced. In Spain information is scarce and, moreover, almost nothing is known about the predators of this species. This study was designed to determine the seasonal trends in abundance of M. feytaudi and its major predators, which might help to improve the biological control of this pest in other areas. Natural P. pinaster stands in the Valencian Community (Spain) were surveyed in 2004. In addition, the seasonal trends in abundance of M. feytaudi and its natural enemies were monitored in three stands over a period of three years (2002, 2005 and 2006). The monitoring was carried by wrapping sticky tapes around tree trunks and using delta traps baited with sexual pheromone. The maritime pine bast scale was detected in all the stands surveyed. At almost all the sites surveyed, three species of predators were captured: Elatophilus nigricornis Zetterstedt (Hemiptera: Anthocoridae), Hemerobius stigma Stephens (Neuroptera: Hemerobiidae) and Malachiomimus pectinatus (Kiesenwetter) (Coleoptera: Malachiidae). The presence of M. pectinatus is noteworthy as this is the first record of this species as a possible predator of M. feytaudi. The results show that M. feytaudi, although differing in its phenology depending on the location, is univoltine in the study area. The prepupae, pupae and adults of M. feytaudi appeared between December and March in colder areas and between October and February in warmer areas. E. nigricornis nymphs are important predators of M. feytaudi, and were abundant when the scale insect (crawlers, prepupae, pupae, male and female adults) was present. The flight period of E. nigricornis and the hemerobiid H. stigma ranged from May to October. However, these flight patterns did not correlate with the presence of the different stages of the bast scale (crawlers, prepupae, pupae, male and female adults) on the surface of tree trunks. The presence of M. pectinatus in large numbers in some stands suggests it might be an important natural regulator, which helps to keep M. feytaudi populations at low densities in the areas of Spain studied. This malachiid shows a strong kairomonal attraction to the sexual pheromone of M. feytaudi and its flight activity is significantly correlated with the presence of crawlers of bast scale. |
Genomic alterations recorded in two species of Chironomidae (Diptera) in the Upper Jurassic limestone area of the Ojców National Park in Poland attributable to natural and anthropogenic factorsParaskeva MICHAILOVA, Ewa SZAREK-GWIAZDA, Andrzej KOWNACKI, El¿bieta WARCHA£OWSKA-SLIWAEur. J. Entomol. 109 (4): 479-490, 2012 | DOI: 10.14411/eje.2012.061 The Ojców National Park is situated in southern Poland in an area of Jurassic limestone, which determines the hydrochemistry of the water in the River Pr±dnik. The geochemical index of the sediment in the River Pr±dnik indicated it is moderately polluted with Pb and Zn, and heavily polluted with Cd compared to unpolluted sediment. The effect of natural and anthropogenic sources on the sediment in the River Pr±dnik and in appearing of structural and functional alterations in the salivary gland chromosomes of two species of Chironomidae, Micropsectra pallidula and Polypedilum convictum, was investigated. Two types of chromosomal rearrangements (inherited and somatic) were identified in the species studied. Inherited heterozygous inversions occurred at a higher frequency (between 5.55%-57.81%) and may have local adaptive value. In M. pallidula a karyotype divergence consisting of fixed chromosome inversions on arms B and E was recorded. As somatic chromosome rearrangements can be caused by stress agents, we suggest that the somatic aberrations in both of the species studied indicate the existence of pollution, i.e. induced stress. On the basis of these somatic rearrangements the somatic index of both species was defined: M. pallidula - 0.346, P. convictum - 0.555. In addition to these rearrangements functional alterations in key structures, Balbiani rings (BRs) and the nucleolar organizer region (NOR) located on chromosome EF, which significantly decreased their transcriptional activity, were recorded in M. pallidula. Changes in the appearance of the telomere region on chromosome G in P. convictum was considered to be a response to the environmental conditions in the River Pr±dnik. It was shown that polytene chromosomes are very sensitive to environmental changes and can be used to detect pollutants in aquatic ecosystems. |
Evaluation of criteria for species delimitation of bagworm moths (Lepidoptera: Psychidae)Veronica CHEVASCO, Jelmer A. ELZINGA, Johanna MAPPES, Alessandro GRAPPUTOEur. J. Entomol. 111 (1): 121-136, 2014 | DOI: 10.14411/eje.2014.013 Accurate identification of species is fundamental for biological research and necessary for species conservation. DNA barcoding is particularly useful when identification using morphological characteristics is laborious and/or unreliable. However, barcodes for species are dependent on the availability of reference sequences from correctly identified specimens. The traditional use of morphology to delimit the species boundaries of Finnish bagworm moths (Lepidoptera: Psychidae: Naryciinae: Dahliciini) is controversial because there is overlap in their morphological characteristics. In addition, there are no suitable molecular markers. We verified the delimitation of seven out of eight previously described taxa, by using the currently standardized COI barcode and phylogenetic inference based on fragments of mitochondrial (COI) and nuclear genes (MDH). Moreover, we compared the results of molecular methods with the outcome of geometric morphometrics. Based on molecular identification, our findings indicate that there are five sexual species (Dahlica and Siederia spp.) and two parthenogenetic species (D. fennicella and D. triquetrella) in Finland. We suggest that molecular methods, together with geometric morphometrics of male genitalia are an effective way of delimiting species of bagworm moths. |
Variation in the shape of the wings and taxonomy of Eurasian populations of the Calopteryx splendens complex (Odonata: Calopterygidae)Saber SADEGHI, Henri J. DUMONTEur. J. Entomol. 111 (4): 575-583, 2014 | DOI: 10.14411/eje.2014.073 We used geometric morphometrics to determine variation in the morphology of the forewings of individuals in 20 populations of Calopteryx splendens s.l. in Eurasia and related these to the circum-specific taxonomy of this taxon. We found differences in shape, with the largest and smallest centroid size of the wings in adjacent northern (orientalis) and western (intermedia) populations in Iran, respectively, so isolation and relationship are not necessarily determined by distance, but often associated with the stream basin inhabited. The variation in wing shape, however, was much greater. with Populations at the eastern edge of the range (Tajikistan, Kyrgyzstan and East Kazakhstan) uniquely different. Oddly, no taxonomic name is associated with them, although they may be among the oldest representatives of the splendens complex. The European and Asian populations are in two separate clades. One of these includes insects with no to a medium-sized wing spot, which does not reach the tip of the wing (waterstoni-group), while the other includes insects with very broad wing spots, or, when short, it extends to the very tip of the wings and most females are androchrome (ancilla or intermedia group). Turkmenistan and northern Iranian population form a separate line inside this clade, which we equate with Calopteryx orientalis. South Albanian and Greek populations are in a separate branch corresponding to ssp. balcanica; two populations from Ireland and Italy form a branch that has no equivalent in traditional taxonomy, while Calopteryx xanthostoma was not identified by its wing shape. Understanding this multitude of phenotypes and the enormous amount of variation within certain populations but not in others becomes easy if one assumes there were two probable late Pleistocene waves of migration, the first of insects lacking spots that migrated east and westwards from the South Black Sea basin, the second, perhaps from the west Caspian, composed of heavily spotted insects with androchromic females. The hybridization between these two waves resulted in the current plethora of colour forms and accounts for why similar phenotypes may turn up independently in widely distant locations. |
Quantitative evidence for spatial variation in the biennial life cycle of the mountain butterfly Erebia euryale (Lepidoptera: Nymphalidae) in the Czech RepublicIrena KLECKOVA, Pavel VRBA, Martin KONVICKAEur. J. Entomol. 112 (1): 114-119, 2015 | DOI: 10.14411/eje.2015.003 Erebia euryale (Esper, 1805) is a montane-zone representative of a Holarctic butterfly genus the species of which occur mainly in alpine areas. As in many mountain insects, E. euryale frequently undergoes a prolonged biennial larval development, which can be synchronised across mountains, resulting in prominent biennial peaks in adult emergence. However, the extant reports are often contradictory, suggesting that populations are not synchronized. We present the first quantitative assessment of the situation in the Czech Republic, based on five years of monitoring adults along transects in three major mountain systems in this country. We detected a two order magnitude difference in biennial fluctuations in adult abundance, with peaks in even years (i.e. 2010, 2012) in the Šumava Mts (southwest Czech Republic). There were less distinct odd year (i.e. 2009, 2011, 2013) peaks in the Hrubý Jeseník Mts (northeast) and no fluctuations from year to year in the number of adults recorded in the Krkonoše Mts (north). Although the mechanisms behind these patterns remain unknown, we hypothesize that rugged terrain desynchronises and flat terrain synchronises the length of development of E. euryale. Finally, the different periodicity in the fluctuations in individual mountain ranges is hypothesized to be affected by interactions with larval parasitoids or reflect the different postglacial histories of respective populations. |
The effects of larval diet on adult life-history traits of the black soldier fly, Hermetia illucens (Diptera: Stratiomyidae)Paola GOBBI, Anabel MARTÍNEZ-SÁNCHEZ, Santos ROJOEur. J. Entomol. 110 (3): 461-468, 2013 | DOI: 10.14411/eje.2013.061 Larvae of Hermetia illucens feed on different types of decomposing organic matter and their development depends on the quality and quantity of food ingested. In this study the effect of three artificial diets was analyzed, namely hen feed, meat meal and a mixture of these two diets. The effects of diet on ovarian development, size, mortality, duration of the larval and pupal stages and sex ratio were studied. Results indicate that the meat meal diet was the worst of the three diets in terms of percentage mortality and duration of the larval and pupal stages. We conclude that food ingested by the black soldier fly larvae determines both the physiological and morphological development of the adults. |
Relation between plant water status and Macrosiphum euphorbiae (Hemiptera: Aphididae) population dynamics on three cultivars of tomatoAnna R. RIVELLI, Vincenzo TROTTA, Irene TOMA, Paolo FANTI, Donatella BATTAGLIAEur. J. Entomol. 110 (4): 617-625, 2013 Deficit irrigation scheduling is used to increase the efficiency with which water is used in many crops including tomato, however a water deficit is predicted to favour phloem feeding insects. We tested if and how different cultivars of tomato grown under water deficit conditions affect the population growth of the aphid Macrosiphum euphorbiae. Three tomato cultivars (Scintilla, Beefmaster and Rio Grande) were used in the experiments. The results for three watering regimes were compared with those of a control, which was well watered every three days: stressed plants received one third of the water supplied to the control over each three-day interval (experiment 1); stressed plants received a gradually decreasing amount of water (100% at the first watering and then 80%, 60%, 50%, 40% and 20%) every three days (experiment 2); stressed plants received the same amount of water as the control but at longer intervals, that is when evident signs of wilting appeared (experiment 3). The results showed that water stress either enhanced, had an adverse effect or had no effect on aphid population growth, depending on the cultivar and watering regime. No difference was recorded in the population dynamics of M. euphorbiae feeding on Beefmaster tomato plants subjected to different levels of water stress. In the case of the cultivar Scintilla, live aphids were less abundant on stressed plants than on well watered ones in experiment 1 and 3 but not in experiment 2. The highest variability in aphid population dynamics on the plants grown under the different water stress protocols was recorded on the cultivar Rio Grande. In experiment 1, the initial peak in aphid numbers was higher on the water stressed plants than on the control and then decreased to lower numbers than on the control. In experiment 2, there were no differences in the numbers of aphids infesting stressed and control plants. In experiment 3, there were fewer aphids on stressed than on control plants after six days, as in experiment 1, but there was no initial peak in aphid numbers. |
First fossil tooth-necked fungus beetle (Coleoptera: Derodontidae): Juropeltastica sinica gen. n. sp. n. from the Middle Jurassic of ChinaChenyang CAI, John F. LAWRENCE, Adam ¦LIPIÑSKI, Diying HUANGEur. J. Entomol. 111 (2): 299-302, 2014 | DOI: 10.14411/eje.2014.034 The first fossil tooth-necked fungus beetle, Juropeltastica sinica gen. n. sp. n., is described and illustrated based on a single impression fossil from the Middle Jurassic Daohugou beds (ca. 165 Ma) of northeastern China. It represents the first definitive fossil belonging to the extant family Derodontidae. Juropeltastica is placed in Derodontidae based on its overall body shape and size, head with complex systems of tubercles and grooves, pronotum with dentate lateral carinae, open mesocoxal cavities bordered by mesepimeron and metanepisternum, excavate metacoxae, and 5-segmented abdomen. The occurrence of a reliable derodontid fossil from 165 million years ago places Derodontidae among the small but growing number of beetle families of known Middle Jurassic age, which is important in the dating of phylogenetic trees. |
Tuta absoluta (Lepidoptera: Gelechiidae): Thermal requirements and effect of temperature on development, survival, reproduction and longevityFlavia da Silva KRECHEMER, Luis Amilton FOERSTEREur. J. Entomol. 112 (4): 658-663, 2015 | DOI: 10.14411/eje.2015.103 Tuta absoluta (Meyrick, 1917) is the main pest of tomato crops in South America. Recently, it was also reported in several countries in Europe and the Middle East. Because of its invasive potential and the lack of information on the biology of T. absoluta, the present study aimed to estimate its thermal requirements and evaluate the effect of temperature on its development, survival, reproduction and longevity. The experiments were carried out at constant temperatures of 10, 15, 20, 25 and 30°C. T. absoluta completed its development at all these temperatures. The thermal requirements were estimated by linear regression; the insects required 416.7 degree-days to complete the cycle from egg to adult, and the lower temperature threshold was estimated to be 8.0°C. The upper temperature threshold estimated for the egg-adult cycle was 37.3°C. The pre-oviposition period was longer at 10°C, but the oviposition period was similar at all the temperatures tested. Fecundity was highest at 20 and 25°C, with averages of 134.8 and 149.1 eggs per female, respectively. The highest percentages of fertile eggs were recorded at 15, 20 and 25°C. At 10 and 30°C, only one egg clutch was laid by T. absoluta. No differences were recorded in the longevity of females and males of T. absoluta. The tomato leaf miner can develop over a wide range of temperatures; however, its reproduction and survival were negatively affected at the extreme constant temperatures tested. The temperature variation recorded in natural environments is suitable for this pest to infest tomato crops. |
Diapause and post-diapause quiescence demonstrated in overwintering Harmonia axyridis (Coleoptera: Coccinellidae) in northwestern EuropeC. Lidwien RAAK-VAN DEN BERG, Peter W. DE JONG, Lia HEMERIK, Joop C. VAN LENTERENEur. J. Entomol. 110 (4): 585-591, 2013 The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is regarded as an invasive species in many parts of the world. In a previous study we hypothesised that H. axyridis enters diapause at the end of October and then shifts to a quiescent state in December in northwestern Europe. In the present study we test this idea of a short, early period of diapause by sampling beetles from their hibernation sites immediately after their migratory flights in October, subsequently keeping them in outdoor cages, and then, after certain time-intervals, measuring the pre-oviposition time under optimal egg-laying laboratory conditions at 25°C. We did this at both short (12L) and long (16L) photoperiods, since a photoperiodic response is an indicator of true diapause, rather than quiescence. A significant, albeit small, difference in pre-oviposition period between the two photoperiods, which disappears in December, corroborates our earlier hypothesis that the ladybirds are in a state of diapause until mid-December. Compared with that of native ladybirds the diapause of H. axyridis generally is relatively short and weak; moreover, it appears to have become shorter over the last decade. This flexibility in diapausing behaviour may be an important factor that contributes to the invasive success of H. axyridis. |
Prevalence of male-killer in a sympatric population of two sibling ladybird species, Harmonia yedoensis and Harmonia axyridis (Coleoptera: Coccinellidae)Suzuki NORIYUKI, Yuichi KAMEDA, Naoya OSAWAEur. J. Entomol. 111 (2): 307-311, 2014 | DOI: 10.14411/eje.2014.029 In predatory ladybirds male embryos in clutches of eggs infected with male-killing bacterial endosymbionts do not hatch and are consumed by female hatchlings. Moreover, it is predicted that infection with male-killing bacteria should be prevalent in a ladybird population if the fitness advantage to female ladybirds due to the resulting reallocation of resources is high. We compared male-killer bacterial prevalence in two sibling species of the ladybird genus Harmonia that use different host ranges. Harmonia yedoensis feeds mostly on the highly elusive pine aphid and its hatchlings can greatly enhance their ability to capture prey and thus their survival by consuming un-hatched eggs in the clutch. In contrast, Harmonia axyridis feeds on a wide range of prey and consumption of un-hatched eggs by the hatchlings does not necessarily increase their foraging success. In the study area where these two species of ladybird occur sympatrically 14 of the 22 females of H. yedoensis (64%) laid clutches of eggs of which approximately only a half hatched and did not produce male offspring, whereas only one of 12 of the females of H. axyridis (8%) exhibited symptoms indicating infection with male-killing bacteria. In the H. yedoensis that exhibited symptoms of being infected with male-killing bacteria, the total allocation of resources to each hatchling, which was provided by laying larger eggs and eating the un-hatched eggs in the clutch, was considerable. These results suggest that the difference in the prevalence of infection with male-killing bacteria in these two species of ladybird may reflect differences in the quality of their prey and their foraging behaviour. |
Bioluminescent assay for evaluating antimicrobial activity in insect haemolymphLibor VOJTEK, Pavel DOBE©, Ender BÜYÜKGÜZEL, Janne ATOSUO, Pavel HYR©LEur. J. Entomol. 111 (3): 335-340, 2014 | DOI: 10.14411/eje.2014.045 We describe an antibacterial assay based on bioluminescence of two Gram negative bacteria, Photorhabdus luminescens and transformed Escherichia coli, which can be used as a real-time measurement of antibacterial activity in insect haemolymph. This method is based on the production of the bioluminescence signal depending on the viability of bacterial cells. We observed a significant rapid dose-dependent decrease in bioluminescence using both bacterial species, and Bombyx mori or Galleria mellonella haemolymph, which was confirmed by the decrease in bacterial viability determined by plating. The humoral origin of the antibacterial activity observed in whole haemolymph was confirmed for haemolymph plasma without haemocytes. Antibacterial activity directed against Gram negative bacteria was recorded in unaffected insect larvae as well as after septic injury; increased antibacterial activity of haemolymph was detected in the latter case confirming the inducibility of antimicrobial agents. We think it is likely that this method could be widely used for determining antibacterial activity in insects and other invertebrates. |
Effects of cold acclimation, cooling rate and heat stress on cold tolerance of the potato tuber moth Phthorimaea operculella (Lepidoptera: Gelechiidae)Chamran HEMMATI, Saeid MOHARRAMIPOUR*, Ali ASGHAR TALEBIEur. J. Entomol. 111 (4): 487-494, 2014 | DOI: 10.14411/eje.2014.063 This study was carried out to investigate the effects of cold acclimation, cooling rate and heat stress on supercooling capacity and cold hardiness of the potato tuber moth (PTM), Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae). Supercooling points (SCP) of first and last instar larvae, prepupae and pupae were -21.8, -16.9, -18.9 and -18.0°C, respectively. Cold acclimation (1-week at 0 and 5°C) did not affect SCPs of acclimated last instar larvae, prepupae and pupae. LT50s (lower lethal temperature for 50% mortality) for first and last instar larvae, prepupae and pupae were -15.5, -12.4, -17.9 and -16.0°C, respectively. Cold acclimation resulted in a significant decrease in mortality of all developmental stages. In addition, the mortality rates of the different developmental stages decreased with decrease in cooling rate. In addition, heat hardening (kept at 40°C for 2 h) significantly reduced mortality of all developmental stages exposed to LT50 conditions, suggesting that heat hardening also affects cold tolerance. Results indicate that none of the stages could tolerate subzero temperatures below their SCPs, indicating that this species might be a chill tolerant insect. These adaptive responses may allow PTM to enhance its cold tolerance and colonize cold regions. |
Effect of military activity on butterfly (Lepidoptera) communities in Korea: Conservation and maintenance of red listed speciesSung-Soo KIM, Tae-Sung KWON, Cheol Lee MINEur. J. Entomol. 112 (4): 770-777, 2015 | DOI: 10.14411/eje.2015.099 Military training areas are increasingly recognized as areas of high biodiversity and habitats for many wild organisms, including threatened or endangered species. However, the information on the ecological value of military training areas is limited because it is difficult access these sites. The aim of this study is to evaluate the effect of military activity on butterfly communities. The survey was carried out in a military training area (MTA) at Inje-gun near the demilitarized zone (DMZ), Inje forest (IJF) a secondary forest and Gwangneung forest (GWF) an old growth forest, from April to October 2008 to 2011. IJF and GWF were selected in order to determine the characteristics of a butterfly community differed in a MTA. Butterfly communities differ greatly among sites. Estimated species richness and species diversity were significantly higher in MTA compared to GWF. Grassland species were abundant in MTA and forest interior species in GWF. Species richness and abundance of red listed species, especially grassland species, were greatest in MTA, but absent in GWF. Military activities were beneficial for red listed grassland species because they maintained an open habitat, which is rare elsewhere in current Korea. This study indicates that MTAs are important in terms of conservation and in providing a refuge for red listed grassland species. |
Chromosome fusion polymorphisms in the grasshopper, Dichroplus fuscus (Orthoptera: Acrididae: Melanoplinae): Insights on meiotic effectsAlberto TAFFAREL, Claudio J. BIDAU, Dardo A. MARTÍEur. J. Entomol. 112 (1): 11-19, 2015 | DOI: 10.14411/eje.2015.010 Robertsonian fusions account for many of the changes in the evolution of the orthopteran karyotype; in their origin, a centric fusion is involved between two acro-telocentric chromosomes, forming a single bi-armed chromosome. It is usual for these rearrangements to be associated with profound changes in meiosis, such as modification in frequency and distribution of chiasmata. Dichroplus fuscus is a South American grasshopper with a wide distribution. In this work we analyzed nine populations from Misiones Province, north-eastern Argentina. This species presents a standard karyotype of 2n = 23/24 (♂/♀) with all chromosomes acro-telocentric and an X0/XX chromosomal sex determining mechanism. This standard karyotype has been modified by the occurrence of two Robertsonian fusions involving chromosomes 1/3 and 2/4; values of fusions per individual (fpi) show a significant increase in the presence of karyotypic polymorphisms towards southern populations. In individuals showing chromosomal rearrangements, we observed a clear redistribution of chiasmata towards distal positions; significant differences were noted between Robertsonian homozygotes (Ho) and heterozygotes (Ht) for chromosomes arms L1 and M3, although this was not the case between Ho and Ht for chromosome arms L2 and M4. With regard to the orientation of trivalents, values obtained for non-convergent orientation were low. |
Different host plant utilization ability of two closely related Melitaea species (Lepidoptera: Nymphalidae)János P. TÓTH, Judit BERECZKI, Zsolt VÉGVÁRI, Edit JUHÁSZ, Zoltán VARGAEur. J. Entomol. 112 (1): 120-125, 2015 | DOI: 10.14411/eje.2015.001 In natural systems plant-insect interactions are influenced by several factors. For instance plants could be characterised by the presence of defensive chemicals and herbivores are forced to evolve resistance against them. There are several studies on induced plant defence, which indicate it can mediate competition between herbivorous insects, shaping host plant choice and community structure. Therefore, realized host plant use can be much narrower than the potential one. A laboratory experiment was done to clear up the possible difference in host plant utilization ability of Melitaea phoebe and Melitaea ornata, especially their utilization of Cirsium pannonicum. The caterpillars were reared individually on three different species of host plant (Ci. pannonicum, Ci. arvense and Centaurea scabiosa). The weights of the larvae were measured every second day and the data analysed using ANOVA. M. phoebe caterpillars developed well and all pupated when fed on Cirsium arvense and Centaurea scabiosa, whereas those fed on Cirsium pannonicum developed poorly and 10% died. In contrast, M. ornata developed well on Ci. pannonicum and the other two host plants. Despite this M. ornata was only found on Ci. pannonicum in Hungary. |
Light intensity affects spatial distribution of Heteroptera in deciduous forestsMartin M. GOSSNEREur. J. Entomol. 106 (2): 241-252, 2009 | DOI: 10.14411/eje.2009.032 Studies on the effect of varying light intensity on the spatial distribution of flying insect communities are rare, particularly in complex ecosystems like forests. The horizontal and vertical distribution of Heteroptera was studied at different scales in a large deciduous forest area, the "Steigerwald", in southern Germany. Diversity was affected by (1) vertical position: it was significantly higher near the ground than in the canopy of beech-dominated forests but similar in oak-dominated forests; within the canopy of beech-dominated forests, diversity was significantly higher in the upper than in the lower canopy of intermixed oak trees but similar in beech trees; (2) canopy cover, but in oak forests the response depended on the vertical position: increasing significantly close to the forest floor with decreasing canopy cover, but showing an opposite trend in the canopy; so that in sparse stands (little canopy cover) diversity was significantly higher near the ground, whereas where the forest canopy was medium or dense diversity was higher in the canopy. Moreover, community composition of Heteroptera near the ground differed from that in the canopy in both forest types and near the ground between stands in oak-dominated forest that had canopies of different densities. Results clearly indicate that light intensity is an important direct or indirect factor structuring Heteroptera communities. While in the canopy differences in leaf quality and microhabitats might be important, near the forest floor it is more likely to be the diversity of herbaceous plants. |
Female sex pheromone gland of the boxwood leafminer, Monarthropalpus buxi (Diptera: Cecidomyiidae): Morphological and behavioural evidencePaola RIOLO, Sara RUSCHIONI, Roxana L. MINUZ, Roberto ROMANI, Nunzio ISIDOROEur. J. Entomol. 111 (1): 75-81, 2014 | DOI: 10.14411/eje.2014.009 Morphological studies were carried out to determine whether females of the boxwood leafminer, Monarthropalpus buxi (Laboulbene) (Diptera: Cecidomyiidae) have a pheromone gland, its position and ultra-structure. In addition, the reproductive behaviour of this gall midge was studied in the laboratory in a wind-tunnel. The source of the sex pheromone was identified as the epidermis of the inter-segmental membrane between the 8th and 9th abdominal segments of females. The epidermis there was hypertrophied and consisted of a unicellular layer of secretory cells with ultra-structural features that include a well developed smooth endoplasmic reticulum and Golgi complexes that are typical of pheromone-producing glands. At adult emergence the sex ratio was 1 : 1. The virgin females extruded their ovipositor and moved it slowly (visible using a video-camera at high magnification), which was followed by mating. The females were monogamous, while the males usually mated several times with different females. Wind-tunnel bioassays using virgin females, ovipositor-ectomised virgins and mated females provided further evidence that virgin females produce a sex pheromone. |
Partially disarticulated new Miocene burrower bug (Hemiptera: Heteroptera: Cydnidae) from Cerová (Slovakia) documents occasional preservation of terrestrial arthropods in deep-marine sedimentsPeter VR©ANSKÝ, Jerzy A. LIS, Ján SCHLÖGL, Martin GULDAN, Tomá¹ MLYNSKÝ, Peter BARNA, Pavel ©TYSEur. J. Entomol. 112 (4): 844-854, 2015 | DOI: 10.14411/eje.2015.090 The state of preservation of the bug Sehirus carpathiensis J.A. Lis, Vr¹anský & Schlögl, sp. n. (Hemiptera: Heteroptera: Cydnidae) from the Lak¹árska Nová Ves Formation at Cerová (Slovakia) supports extremely rapid sinking and burial in upper bathyal Early Miocene sediments. The specimen originated from land at most a few kilometers away, but transport via a river can be excluded as the head and wings are still attached. Its most likely source based on fossil flora and the habitat of several living representatives of the genus is a riparian habitat in an adjacent area of land. Phylogenetically the new species is closely related to both Oligocene and living representatives of the genus, thus indicating an early Paleogene origin of the genus (like many other living insect genera). The observations based on two samples from one area (Czech Republic) indicate that terrestrial insects are occasionally preserved in deep marine environments, but overlooked due to their usually fragmentary and obscure nature of the preservation. The newly developed KVANT full-profile confocal measurement revealed a sample roughness Ra = 1.3-2.0 µm and abdomen submerged in the matrix 300 µm deeper than the more rigid pronotum. |
Does the prediction of the time of egg hatch of Thaumetopoea processionea (Lepidoptera: Notodontidae) using a frost day/temperature sum model provide evidence of an increasing temporal mismatch between the time of egg hatch and that of budburst of Quercus robur due to recent global warming?Eiko WAGENHOFF, Annika WAGENHOFF, Rainer BLUM, Holger VEIT, Daniel ZAPF, Horst DELBEur. J. Entomol. 111 (2): 207-215, 2014 | DOI: 10.14411/eje.2014.030 Thaumetopoea processionea is a serious defoliator of oak and of medical concern whose abundance has consistently increased throughout Europe during the past two decades. This study validates a previously published frost day/temperature sum model for predicting time of egg hatch of this species using five years of recent field data from South-West Germany. This model proved satisfactory for predicting the time of egg hatch of T. processionea. Hence, the model was used to retrospectively predict the time of egg hatch of T. processionea in the Karlsruhe area, which indicates that the time of egg hatch has fluctuated over the past 130 years. In the last two decades, however, predicted time of egg hatch is much earlier than the long-term average due to the increase in winter and early spring temperatures. Comparison of predicted time of egg hatch of T. processionea and long-term records of the time of foliation of its common host Quercus robur revealed that in the study area the temporal advance in the timing of both events was similar. This is not in accordance with recently published research on spring-feeding folivores, which report a diverging trend in the timing of egg hatch and budburst of their host plants as a consequence of human-induced climate change. |
Stage specific consumption and utilization of aphids, conspecific and heterospecific eggs by two species of Coccinella (Coleoptera: Coccinellidae)Bhupendra KUMAR, Mahadev BISTA, Geetanjali MISHRA, OMKAREur. J. Entomol. 111 (3): 363-369, 2014 | DOI: 10.14411/eje.2014.046 The nutritive quality of aphids, conspecific and heterospecific eggs as food for ladybirds is a controversial issue. If ladybirds find aphids more palatable than eggs then they are more likely to efficiently exploit and be biocontrol agents of aphids. If eggs of conspecific or heterospecific ladybirds are more palatable than aphids these biocontrol agents may either impede aphid pest suppression or become a threat to other species of ladybirds. Thus, prior to formulating predatory guilds of ladybirds the nutritive quality of their eggs compared to that of the target aphid needs to be determined. In this regards, the present study evaluates the nutritive quality of an ad libitum supply of: (i) pea aphid, Acyrthosiphon pisum (Harris), (ii) conspecific eggs and (iii) heterospecific eggs as food for Coccinella septempunctata (L.) and Coccinella transversalis Fabricius (Coleoptera: Coccinellidae), by determining the stage specific predation and developmental attributes of these two ladybirds reared on these diets. The conversion efficiencies and growth rates of young (first, second and third) larvae of both species of ladybirds were higher than those of fourth instar larvae and the consumption rates of fourth instar were higher than those of young larvae when fed on the three diets. When fed aphids the pre-imaginal development was faster, the consumption rates, conversion efficiencies and growth rates higher, adults bigger and mortality lower than when fed on conspecific eggs. The larvae of C. septempunctata consumed and completed their development when fed eggs of C. transversalis but the first instar larvae of C. transversalis did not consume the eggs of C. septempunctata and died of starvation. The dominance of C. septempunctata over C. transversalis in agricultural fields may be due to it consuming and utilizing aphids more efficiently and as a consequence growing faster and suffering a lower mortality along with its ability to consume and complete its development on eggs of C. transversalis. Thus, both these predators may not continue to coexist as predators of the pea aphid in agricultural fields since C. septempunctata may become a greater threat to C. transversalis in the future. |
Comparison of the developmental time of Bracon hebetor (Hymenoptera: Braconidae) reared on five different lepidopteran host species and its relationship with digestive enzymesDorna SAADAT, Ali R. BANDANI*, Mehdi DASTRANJEur. J. Entomol. 111 (4): 495-500, 2014 | DOI: 10.14411/eje.2014.069 Bracon (Habrobracon) hebetor Say is a polyphagous parasitoid of lepidopteran larvae, including those of the family Pyralidae. There are many reports that this parasitoid attacks the larvae of stored product and field crop pests. However, there is little information on the biological parameters of this parasitoid attacking different lepidopteran hosts or the effect of the hosts on the digestive enzymes of the parasitoid. Hence, in the current study the effect of different lepidopteran hosts, Ectomyelois ceratoniae, Plodia interpunctella, Ephestia kuehniella, Helicoverpa armigera and Malacosoma disstria, on the biological parameters and digestive enzymes (α-amylase and proteases) of this parasitoid were investigated. The parasitoid performed better on stored product pests, such as E. kuehniella and P. interpunctella, than field crop pests, such as H. armigera and M. disstria. For example, in terms of percentage egg hatch, rate of development, off-spring sex ratio and adult dry mass Bracon hebetor did much better when it parasitized stored product insects than field crop insects (P < 0.05). Interestingly, the quality and quantity of the proteases and α-amylase of the parasitoid larvae parasitizing stored product and field crop pests differed. The greatest activity of these enzymes was recorded in the gut of those parasitoids that were reared on stored product insects (P. interpunctella and E. kuehniella). It is concluded that stored product insects, which feed on a diet rich in sugar and glycogen, provide physiological conditions that are more suitable for the parasitoid than field crop insects, which feed on diet rich in terpenes and tannins. |
Morphometrics, life history and population biology of the Ponto-Caucasian slave-making ant Myrmoxenus tamarae (Hymenoptera: Formicidae)Nana GRATIASHVILI, Masaki SUEFUJI, Shalva BARJADZE, Jürgen HEINZEEur. J. Entomol. 112 (1): 175-179, 2015 | DOI: 10.14411/eje.2015.025 Abstract. The ant genus Myrmoxenus consists of about ten socially parasitic species including active slave-makers and workerless "degenerate slave-makers". Myrmoxenus tamarae was previously known only from type material, two workers collected at Daba, Georgia and nothing was known about its life history, colony structure or the morphology of its sexuals. An inspection of colonies of M. tamarae near the type locality in 2010 indicates that young queens of M. tamarae invade Temnothorax nests and kill the host queen by throttling. The simultaneous presence of two slave species in a single colony (an undescribed species related to T. nylanderi and a species morphologically resembling T. unifasciatus) indicates that M. tamarae is an active slave-maker. The genetic structure of the colonies matches that expected for a monogynous and monandrous ant, but three of eight colonies inspected appeared to contain workers belonging to an additional genetic lineage. |
Determining the season of death from the family composition of insects infesting carrionThiago De Carvalho MORETTI, Vinícius BONATO, Wesley Augusto Conde GODOYEur. J. Entomol. 108 (2): 211-218, 2011 | DOI: 10.14411/eje.2011.029 Determining the season of death by means of the composition of the families of insects infesting carrion is rarely attempted in forensic studies and has never been statistically modelled. For this reason, a baseline-category logit model is proposed for predicting the season of death as a function of whether the area where the carcass was exposed is sunlit or shaded and of the relative abundance of particular families of carrion insects (Calliphoridae, Fanniidae, Sarcophagidae, and Formicidae). The field study was conducted using rodent carcasses (20-252 g) in an urban forest in southeastern Brazil. Four carcasses (2 in a sunlit and 2 in a shaded area) were placed simultaneously at the study site, twice during each season from August 2003 through June 2004. The feasibility of the model, measured in terms of overall accuracy, is 64 ± 14%. It is likely the proposed model will assist forensic teams in predicting the season of death in tropical ecosystems, without the need of identifying the species of specimens or the remains of carrion insects. |



