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Some ethological aspects of the trophobiotic interrelations between ants (Hymenoptera: Formicidae) and larvae of the sawfly Blasticotoma filiceti (Hymenoptera: Blasticotomidae)Tatiana A. NOVGORODOVA, Olga B. BIRYUKOVAEur. J. Entomol. 108 (1): 47-52, 2011 | DOI: 10.14411/eje.2011.006 Some ethological aspects of the interrelations between ants and the larvae of Blasticotoma filiceti Klug, 1834 were investigated in the Altai Republic and Novosibirsk Region in 2006-2008. The interactions of ants with the larvae of this sawfly are determined by the concealed way of life style of B. filiceti. The majority of the ant-sawfly encounters occurred near holes in fern fronds at the moment when larvae excreted liquid or left their tunnels before descending to the soil prior to overwintering. Sawfly larvae visited by more aggressive ants, such as Formica s. str., leave the fern fronds slowly, which enables them to avoid inciting attacks by ants. The behaviour of the ants while collecting the larval excretion is similar to their behaviour at sugar troughs. The organisation of the collecting larval excreta by ants was investigated in detail in the cases of Formica polyctena Förster, 1850 and Myrmica rubra Linnaeus, 1758. The individual fern plants with sawfly larvae are attended by relatively constant groups of foragers in both cases. However, the highly social red wood ants interact with sawfly larvae in a more complex way. While the working groups of M. rubra tending sawfly larvae consist only of non-aggressive "unspecialized" foragers, those of F. polyctena include also a few "on duty" ants that protect the trophobionts, at least from the other ants. |
A review of Fennoscandian arthropods living on and in snowSigmund HÅGVAREur. J. Entomol. 107 (3): 281-298, 2010 | DOI: 10.14411/eje.2010.037 A permanent snow cover for several months is typical for large parts of Norway, Sweden and Finland. Snow layers thicker than about 20 cm insulate the soil surface and stabilize the ground temperature close to 0°C. Many ground-living invertebrates are active at this temperature in the subnivean air space. From this "base camp", some invertebrates migrate upwards to use the snow as a substrate. The intranivean fauna consists of springtails (Collembola) and mites (Acari) that are small enough to move within the narrow pores between snow crystals. The supranivean fauna consists of various invertebrates that are active on the snow surface. Some of them are Collembola that have migrated through the snow layers. However, most of them are larger insects and spiders which migrate between the subnivean and supranivean habitats following air channels which are naturally created along tree stems, bushes etc. penetrating the snow. Likewise, certain Chironomidae and Plecoptera, hatching from winter-open rivers and brooks, are active on the snow surface. The supranivean arthropod fauna has the following characteristics: 1. It is a weather dependent assemblage of species, coming and going with changes in air temperature, cloud cover, and wind. Below ca. -6°C animals are absent, but at temperatures around or above zero, many groups can be simultaneously active on snow. 2. The snow surface fauna shows phenological changes throughout the winter, as certain species and groups are mainly active during certain months. 3. Some invertebrates are highly specialized and take advantage of the snow surface as an arena in their life cycle. Examples are Hypogastrura socialis (Collembola), and the two wingless insects Chionea sp. (Diptera: Limoniidae) and Boreus sp. (Mecoptera). They use the smooth snow surface for efficient migration. Chionea sp. and Boreus sp. lay their eggs during the snow-covered period, while H. socialis migrates to create new colonies. The cold tolerant spider Bolephthyphantes index is unique in constructing webs in small depressions on the snow, to catch migrating Collembola. Various adaptations for using the snow as a substrate are discussed. Besides physiological and morphological adaptations, snow surface arthropods show special behavioural adaptations. Most conspicuous is the ability of several Collembola species to navigate during migration, using the position of the sun for orientation. Furthermore, in Collembola and Mecoptera, jumping as an original mechanism to escape predators has independently evolved into a migrating mechanism. An evolutionary potential exists for more invertebrate groups to take advantage of snow as a substrate in their life cycle. For instance, several more cold tolerant spiders might evolve the ability to catch migrating Collembola on snow. |
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. |
A fossil head of an enicocephalomorphan (Hemiptera: Heteroptera) from England revisited: Identity of the first fossil species of Enicocephalidae from EuropePavel ©TYSEur. J. Entomol. 107 (3): 455-460, 2010 | DOI: 10.14411/eje.2010.052 † Pyrenicocephalus jarzembowskii, gen. et sp. n. (Hemiptera: Heteroptera: Enicocephalomorpha: Enicocephalidae: Enicocephalinae) from Early Eocene, London Clay, England, Isle of Sheppey, is described and illustrated according to the unique pyritized adult head reported as a larval enicocephalid head by Jarzembowski (1986). The head anatomy of similar and related genera of Enicocephalinae is compared and the close relationship of the new genus to a clade including the extant genera Oncylocotis, Embolorrhinus and Hoplitocoris is suggested, most probably as the sister genus to Hoplitocoris (presently with Afrotropical, East Palaearctic and Oriental range). |
Genetic polymorphism in "mixed" colonies of wood ants (Hymenoptera: Formicidae) in southern Finland and its possible originJulita KORCZYŃSKA, Marta GAJEWSKA, Malgorzata PILOT, Wojciech CZECHOWSKI, Alexander RADCHENKOEur. J. Entomol. 107 (2): 157-167, 2010 | DOI: 10.14411/eje.2010.021 Wood ant colonies that appear to consist of individuals representing different species are described in several previous papers. The present study is the first to elucidate the genetic basis of the spectacular morphological variability observed within such colonies. Two seemingly mixed colonies (FM-1 and FM-2) from southern Finland were investigated. On the basis of the morphology of their workers these colonies were comprised of individuals with phenotypes typical of Formica rufa L., F. polyctena Först., and F. aquilonia Yarr. The sequence of an mtDNA fragment (5' end of the cytochrome b gene) was used to examine the phylogenetic relationships among haplotypes of workers from homogeneous colonies of different wood ant species and the two supposedly mixed colonies, and to sort the individuals within the colonies into matrilines. Six microsatellite loci were used to analyse the genetic differentiation between colonies and among workers within colonies, and to detect putative hybrids. The results show that, independently of their phenotype, workers from the "mixed" colonies were genetically more similar to other individuals in their colony than to those in the homogeneous F. rufa, F. polyctena or F. aquilonia colonies. However, while colony FM-1 consisted of offspring of the same queen or more likely several maternally related queens, colony FM-2 consisted of the offspring of at least four unrelated queens. The data suggest hybridisation between F. polyctena × F. aquilonia and F. polyctena × F. rufa (and possibly subsequent mating between these hybrids) as the most probable mechanism leading to the existence of these two colonies, which implies that the hybrids are fertile. This study shows that colonies of wood ant hybrids can arise spontaneously and persist under natural conditions. The results also revealed that even some morphologically homogeneous colonies are genetically heterogeneous. In the case of closely related, morphologically similar species that interbreed, morphology can be a bad predictor of genetic differences between individuals. |
Does climate influence phenological trends in social wasps (Hymenoptera: Vespinae) in Poland?Piotr TRYJANOWSKI, Tadeusz PAWLIKOWSKI, Krzysztof PAWLIKOWSKI, Weronika BANASZAK-CIBICKA, Tim H. SPARKSEur. J. Entomol. 107 (2): 203-208, 2010 | DOI: 10.14411/eje.2010.027 Responses of insects to recent climate change have been well documented in a number of taxa, but not in wasps. This study examined shifts in phenology of the two most important wasp species (Vespa crabro and Vespula germanica) in Poland over the last three decades. Both species showed similar temporal trends, advancing their phenology after the early 1980s, but this pattern was detected only for workers not for the appearance of queens. The appearance times for V. germanica were negatively related to mean April temperature, appearing earlier in years with warmer springs, and positively related to precipitation in April. The studied species advanced aspects of their phenology, but linking this to temperature was not achieved for V. crabro suggesting that we have to pay more attention to the life history traits of the study organisms. |
Lepidosina, a new genus of New World Limosininae (Diptera: Sphaeroceridae)Stephen A. MARSHALL, Matthias BUCK, Owen LONSDALEEur. J. Entomol. 104 (3): 573-599, 2007 | DOI: 10.14411/eje.2007.074 The New World genus Lepidosina Marshall & Buck gen. n. is described including nine new and two previously described species: L. angusticercus Marshall & Buck sp. n. (Caribbean, Central and South America), L. argentinensis Marshall & Buck sp. n. (Argentina), L. cubensis Marshall & Buck sp. n. (Cuba), L. evanescens Marshall & Buck sp. n. (Central and South America), L. gibba (Spuler) comb. n. (Florida, Caribbean), L. inaequalis (Malloch) comb. n. (southern U.S.A., Central America, Venezuela), L. multispinulosa Marshall & Buck sp. n. (Ecuador, Peru), L. platessa Marshall & Buck sp. n. (Bolivia), L. proxineura Marshall & Buck sp. n. (Brazil), L. quadrisquamosa Marshall & Buck sp. n. (Venezuela), and L. rutricauda Marshall & Buck sp. n. (Colombia to Peru). Keys to males and females are provided, and the species level phylogeny is analyzed based on a matrix of 24 morphological characters. The sister group of this well-defined, highly apomorphic genus remains unknown. Most species are restricted to lowland habitats. Larvae and puparia of Lepidosina remain unknown. |
Temporal effects of multiple mating on components of fitness in the two-spot ladybird, Adalia bipunctata (Coleoptera: Coccinellidae)Penelope R. HADDRILL, David M. SHUKER, Sean MAYES, Michael E.N. MAJERUSEur. J. Entomol. 104 (3): 393-398, 2007 | DOI: 10.14411/eje.2007.058 Insects have provided much of the best evidence to date concerning possible costs and benefits of multiple mating, and here we investigate the benefits of polyandry in the two-spot ladybird, Adalia bipunctata, by attempting to replicate the highly promiscuous mating system in this species. We compared the temporal pattern of reproductive success of females mated multiple times to one male with that of females mated an equal number of times to multiple males, and found transient differences in offspring production and hatch rate over time. Our data suggest that polyandrous females benefit from multiple mating in some circumstances, but the patterns are complex. Following how both the costs and benefits to mating accrue over time will be necessary if we are to fully understand why polyandry evolves. |
Sexual dimorphism and light/dark adaptation in the compound eyes of male and female Acentria ephemerella (Lepidoptera: Pyraloidea: Crambidae)Ting Fan (Stanley) LAU, Elisabeth Maria GROSS, Victor Benno MEYER-ROCHOWEur. J. Entomol. 104 (3): 459-470, 2007 | DOI: 10.14411/eje.2007.066 In the highly sexual-dimorphic nocturnal moth, Acentria ephemerella Denis & Schiffermüller 1775, the aquatic and wingless female possesses a refracting superposition eye, whose gross structural organization agrees with that of the fully-winged male. The possession of an extensive corneal nipple array, a wide clear-zone in combination with a voluminous rhabdom and a reflecting tracheal sheath are proof that the eyes of both sexes are adapted to function in a dimly lit environment. However, the ommatidium of the male eye has statistically significantly longer dioptric structures (i.e., crystalline cones) and light-perceiving elements (i.e., rhabdoms), as well as a much wider clear-zone than the female. Photomechanical changes upon light/dark adaptation in both male and female eyes result in screening pigment translocations that reduce or dilate ommatidial apertures, but because of the larger number of smaller facets of the male eye in combination with the structural differences of dioptric apparatus and retina (see above) the male eye would enjoy superior absolute visual sensitivity under dim conditions and a greater resolving power and ability to detect movement during the day. The arrangement of the microvilli in the rhabdom of both genders suggests that their eyes are polarization-sensitive, an ability they would share with many aquatic insects that have to recognize water surfaces. Although sexual recognition in A. ephemerella is thought to chiefly rely on pheromones, vision must still be important for both sexes, even if the females are wingless and never leave their watery habitat. Females swim actively under water and like their male counterparts, which fly above the surface of the water, they would have to see and avoid obstacles as well as potential predators. This, together with a small incidence of winged females, we believe, could be the reason why the eyes of female A. ephemerella are less regressed than those of other sexually dimorphic moths, like for instance Orgyia antiqua. Another, but difficult to test, possibility is that male and female A. ephemerella have diverged in their behaviour and habitat preferences less long ago than other sexually dimorphic moths. |
Ecology of a relict population of the vulnerable butterfly Pyrgus sidae on the Iberian Peninsula (Lepidoptera: Hesperiidae)Juan L. HERNÁNDEZ-ROLDÁN, Miguel L. MUNGUIRA, José MARTÍNEur. J. Entomol. 106 (4): 611-618, 2009 | DOI: 10.14411/eje.2009.077 There are isolated populations of the endangered butterfly, Pyrgus sidae, on the Iberian Peninsula. The mark-release-recapture method was used to study the population parameters, the use of resources and the spatial distribution of a population in the centre of Spain. The estimated number of males and females within the population were similar and did not differ significantly from a ratio of 1 : 1. Total population size was estimated to be 569 ± 83 individuals. Potentilla recta is the principal adult nectar source and larval food plant, and its abundance is correlated with the number of marked and recaptured butterflies. The average total distance moved between capture and recapture was significantly greater for males than females, but the average daily distances moved were similar for both sexes. The spatial distribution of the movements of males and females was of a uniform type and lacked a predominant flight direction, which is typical of sedentary species. Continuing the traditional land use (cattle grazing or hay mowing) of the habitat of the species keeps the habitat open, which is necessary if the butterfly is to survive at this locality. These management practices favour P. recta, which would otherwise succumb to competition from invasive shrubs. Taking into account the habitat requirements of this species, it is important to conserve the mosaic of meadows already present in the area. |
Heteropterans as aphid predators in inter-mountain alfalfaXavier PONS, Belén LUMBIERRES, Ramon ALBAJESEur. J. Entomol. 106 (3): 369-378, 2009 | DOI: 10.14411/eje.2009.047 The relationships between predatory Heteroptera and their potential prey species were investigated during two crop seasons in an inter-mountain area close to the Pyrenees (Iberian Peninsula). Regression was used to analyze the potential numerical responses shown by heteropterans to aphids and other potential prey during alfalfa intercuts (the plant growth period between cuts) of high aphid occurrence. The most abundant heteropterans were Orius spp., Nabis spp. and mirids, and all were present in alfalfa stands throughout the season. Acyrthosiphon pisum was the prevalent species during the 2nd intercut, Therioaphis trifolii during the 4th and Aphis craccivora during the 5th. We performed simple regression analysis between the Orius sp., Nabis sp. and mirids and the prevalent aphid species, forward multiple regression analysis between heteropterans and all possible soft-bodied prey species; and both analyses for coccinellids, as relative aphid predator specialists. The heteropterans responded numerically to A. pisum but not to T. trifolii or A. craccivora. Heteropterans also showed numerical responses to other potential prey (leafhoppers, thrips, and other soft bodied prey) that remained at low densities throughout the season. All these preys may contribute to the presence of heteropterans in alfalfa stands throughout the season. The results suggest that heteropterans may contribute to reduce A. pisum, particularly at the beginning of the growing season, and on other potential pests when they invade or recolonize alfalfa, and may help to delay or prevent the build-up of these pest populations. |
On top of a Mediterranean Massif: Climate change and conservation of orophilous moths at the southern boundary of their range (Lepidoptera: Macroheterocera)Stefano SCALERCIOEur. J. Entomol. 106 (2): 231-239, 2009 | DOI: 10.14411/eje.2009.031 During the last few decades the tree line has shifted upward on Mediterranean mountains. This has resulted in a decrease in the area of the sub-alpine prairie habitat and an increase in the threat to strictly orophilous moths that occur there. This also occurred on the Pollino Massif due to the increase in temperature and decrease in rainfall in Southern Italy. We found that a number of moths present in the alpine prairie at 2000 m appear to be absent from similar habitats at 1500-1700 m. Some of these species are thought to be at the lower latitude margin of their range. Among them, Pareulype berberata and Entephria flavicinctata are estimated to be the most threatened because their populations are isolated and seem to be small in size. The tops of these mountains are inhabited by specialized moth communities, which are strikingly different from those at lower altitudes on the same massif further south. The majority of the species recorded in the sub-alpine prairies studied occur most frequently and abundantly in the core area of the Pollino Massif. Species and, as a consequence, communities found at high altitudes are highly vulnerable to climate warming, and need further monitoring. |
Evolutionary history and patterns of differentiation among European Maniola butterflies (Lepidoptera: Satyrinae)Andrea GRILL, Erasmia GKIOKIA, Nadir ALVAREZEur. J. Entomol. 103 (3): 613-618, 2006 | DOI: 10.14411/eje.2006.082 Phylogenetic relationships of European Maniola butterflies are reconstructed using molecular sequences from two regions of the mitochondrial DNA, cytochrome oxidase subunit I (COI) and cytochrome b (Cytb). A total of 988 base pairs (486 for Cytb, and 502 for COI) were aligned for 15 individuals of Maniola and an outgroup species. The phylogenetic tree obtained through Bayesian inference analysis of the combined data sets shows evidence that the island endemic M. chia is indistinguishable from M. jurtina on the basis of the mtDNA genes studied. Net nucleotide divergence between M. jurtina and M. chia is 0.4%, but 2% between the M. jurtina and the M. nurag clade. A phenetically distinct entity of individuals from Sardinia appears to be a hybrid between M. nurag and M. jurtina. The southern and northern European ecotypes of M. jurtina, which differ in the summer aestivation period of the southern type, are not structured genetically at the level of coding mtDNA genes. Divergence time between M. nurag and M. jurtina was estimated to be 1.1 to 1.2 million years. Speciation most likely took place in the early Pleistocene as a consequence of the isolation of Sardinia, when the sea reflooded the Mediterranean basin after the Messinian crisis (about 5 million years ago). |
Chemical cues mediating aphid location by natural enemiesEduardo HATANO, Grit KUNERT, J.P. MICHAUD, Wolfgang W. WEISSEREur. J. Entomol. 105 (5): 797-806, 2008 | DOI: 10.14411/eje.2008.106 There is increasing evidence that chemical cues play a pivotal role in host selection by the natural enemies of aphids. We use Vinson's (1976) division of the host selection process into habitat location, host location and host acceptance for both parasitoids and predators and review what is known about the role of semiochemicals in aphid selection by natural enemies. For habitat location (i.e. detection of the host plant), volatiles emitted by plants after aphid attack have been described for a number of plant-aphid interactions. These synomones indicate not only the presence of an aphid host plant to the predator or parasitoid, but also the presence of aphids. Volatiles emitted from undamaged host plants are often attractive to aphid parasitoids, but less so for predators. Host location by the natural enemy on the food plant is guided by semiochemicals that mostly originate from the aphids, in particular aphid alarm pheromone, honeydew, or the smell of the aphid itself. Host acceptance is guided by contact chemicals for both predators and parasitoids. In parasitoids, host recognition may be based on visual cues or on contact chemicals on the aphid's cuticle, whereas host acceptance is ultimately based on as yet unknown substances within the aphid's hemolymph. While it appears that many predators and parasitoids are attracted to the same semiochemicals, synergistic and antagonistic interactions among chemical substances have only rarely been investigated. More research into model systems is needed, not only to identify important semiochemicals, but also to determine their range of attraction. Recent progress in the development of analytical techniques has created new opportunities to improve our understanding of the chemical ecology of aphid-natural enemy interactions in the coming years. |
Brood attending by females of the hyperparasitoid Trichomalopsis apanteloctena (Hymenoptera: Pteromalidae) on cocoon clusters of its host, Cotesia kariyai (Hymenoptera: Braconidae) and its effects on reproduction, development and survivalNaoto TAKAI, Yutaka NAKAMATSU, Jeffrey A. HARVEY, Ken MIURA, Toshiharu TANAKAEur. J. Entomol. 105 (5): 855-862, 2008 | DOI: 10.14411/eje.2008.113 Theoretical models predict that brood guarding may evolve in situations where eggs are costly to produce or when handling times are long. This study reveals that females of the secondary hyperparasitoid Trichomalopsis apanteloctena guarded cocoon broods of Cotesia kariyai, a gregarious endoparasitoid. Hyperparasitoid females also monopolized host resources and protected their offspring by driving away other conspecific hyperparasitoid females. The females exhibited antagonistic behavior towards competitors through threatening body postures, biting and chasing. Using a video camera to determine how long a hyperparasitoid female attended and parasitized cocoons within a single host brood, it was found that after about 4 days, cocoon guarding behavior became much less apparent. Moreover, more than 90% of hosts were typically parasitized by a hyperparasitoid female over the course of 4 days after she commenced brood guarding. Observations of egg production during a female's lifetime revealed a physiological interval rhythm that typically lasted 3-4 days, which correlates almost exactly with the period during which the cocoons were guarded. To confirm the giving-up time for a host cocoon brood, hyperparasitoid females were given access to 24 h-old cocoon clusters, each containing 60-100 individual cocoons. Ninety percent of the females remained on cocoons for approximately 72 h. Furthermore, twenty-five percent of wasps continued attending and presumably guarding host cocoon broods for more than 138 h after the female first attended the brood. C. kariyai larvae pupate within a few hours of egression from their host and emerge as adults about 5 days (120 h) later. Therefore, many hyperparasitoid females continued to guard older host cocoons of greatly reduced quality as a resource for their progeny and some even after eclosion of the primary parasitoid. Late-brood guarding enabled a hyperparasitoid female to protect her own progeny from other hyperparasitoid females that readily attacked and killed them when she was removed. Our study thus reveals that extended guarding behavior is an adaptive mechanism that probably plays an important role in the survival of the original brood. |
Taxonomical revision of the Longitarsus capensis species-group: An example of Mediterranean-southern African disjunct distributions (Coleoptera: Chrysomelidae)Maurizio BIONDI, Paola D'ALESSANDROEur. J. Entomol. 105 (4): 719-736, 2008 Southern-African Longitarsus capensis species-group, which is closely related to the Mediterranean anchusae species-group is revised. L. capensis species-group includes 15 species, 8 of which are new to science: Longitarsus capensis Baly, 1877, L. cedarbergensis Biondi, 1999, L. luctuosus Biondi, 1999, L. lugubris Biondi, 1999, L. melanicus Biondi, 1999, L. neseri Biondi, 1999, L. transvaalensis Biondi, 1999, L. afromeridionalis sp.n., L. debiasei sp.n., L. grobbelaariae sp.n., L. hexrivierbergensis sp.n., L. malherbei sp.n., L. piketbergensis sp.n., L. rouxi sp.n., and L. sudafricanus sp.n. A key to all the species is presented as well as line drawings of male and female genitalia, scanning electron micrographs of some diagnostic morphological characters, and auto-ecological and zoogeographical data. Relationships within the capensis-group, and between the anchusae and capensis-group are better defined and hypotheses explaining the separate distributions of Mediterranean and south African anchusae and capensis species-groups proposed. Finally, the host-plant shift from native Lobostemon spp. to the introduced plant Echium plantagineum L. shown by some species of the capensis group is also discussed. |
INTERNATIONAL SYMPOSIUME.W. Evans, I. Hodek, N.G. Kavallieratos, E. Lucas, M. Mackauer, J.P. MichaudEur. J. Entomol. 105 (3): 365-368, 2008 | DOI: 10.14411/eje.2008.046 INTERNATIONAL SYMPOSIUM ECOLOGY OF APHIDOPHAGA 10, Athens, September 2007 Organized by the Benaki Phytopathological Institute, Kifissia, Attica, and the Agricultural University of Athens |
Apple aphid, Aphis spp. (Hemiptera: Aphididae), and predator populations in an apple orchard at the non-bearing stage: The impact of ground cover and cultivarBruno FRÉCHETTE, Daniel CORMIER, Gérald CHOUINARD, Franz VANOOSTHUYSE, Éric LUCASEur. J. Entomol. 105 (3): 521-529, 2008 | DOI: 10.14411/eje.2008.069 A two-year field experiment was conducted to determine whether a conservation biological control strategy could be applied to enhance the biological control of green apple aphids, Aphis spp., in a high-density and scab-resistant apple orchard at the non-bearing stage. The natural occurrence of aphid predators and their impact on aphid populations were evaluated in 2005. The impact of predation on aphid densities was evaluated by comparing a predator exclusion treatment with a control. In 2006, the possibility to enhance predator abundance/performance and aphid biological control with a flowering ground cover was tested: trees were grown either with a flowering ground cover of phacelia, Phacelia tanacetifolia Bentham, and buckwheat, Fagopyrum esculentum Moench, or with a conventional ground cover of mixed Poaceae species. In 2006, it was also determined whether aphid densities differ between Liberty and Topaz, 2 scab-resistant cultivars. Results indicate that the predatory arthropod community was dominated by Coccinellidae, Cecidomyiidae, and various spider species. The ladybird community was dominated by the exotic species Harmonia axyridis Pallas, and the abundance of this species was correlated with aphid density. Naturally occurring predators had little impact on aphid abundance, although the proportion of trees with aphid colonies was greater in the predator exclusion treatment on two consecutive dates in 2005. Ground cover types had no impact on aphid densities. The oviposition response of Cecidomyiidae to aphid density was greater in Liberty trees with flowering ground cover than with the conventional ground cover. Conversely, the response of ladybird adults to aphid density was more important in Topaz trees with the conventional ground cover than with the flowering ground cover. Finally, no difference occurred in aphid abundance between Liberty and Topaz trees. Those results are discussed from a biological control and ecological point of view. |
Flower visiting Neuroptera: Mouthparts and feeding behaviour of Nemoptera sinuata (Nemopteridae)Harald W. KRENN, Barbara-Amina GEREBEN-KRENN, Bernhardt M. STEINWENDER, Alexi POPOVEur. J. Entomol. 105 (2): 267-277, 2008 | DOI: 10.14411/eje.2008.037 The mouthparts of the spoon-winged lacewing Nemoptera sinuata are adapted for the uptake of pollen and nectar. Form and function of the mouthparts are described, and the technique of food uptake is discussed in context with flower-visiting behaviour and floral architecture of the preferred flowers. The maxillae are the main organs for food uptake. The brush-shaped laciniae, galeae and maxillary palpi form a functional unit which can be extended by the action of the cardo-stipes joint. Video analyses of the mouthpart movements distinguished different patterns of maxillary motions which occur in nectar feeding or pollen collecting. The flower-visiting behaviour and the specialised mouthparts of the Nemopteridae are derived traits which probably evolved from predatory and biting/chewing mouthparts within the Neuroptera. |
Chromosome number, karyotype morphology, heterochromatin distribution and nuclear DNA content of some talitroidean amphipods (Crustacea: Gammaridea)Angelo LIBERTINI, Renata TRISOLINI, Massimiliano RAMPINEur. J. Entomol. 105 (1): 53-58, 2008 | DOI: 10.14411/eje.2008.007 Chromosome number, karyotype formula, C-banding pattern, genome size and DNA base composition were studied in three species of Hyalidae and seven species of Talitridae. A karyotype of 25 chromosome pairs, with median centromeres (FN = 100), was found in all the species of Talitridae analysed and Apohyale prevostii. Genome size (C-value) varies among Talitrida from 0.94 pg in Apohyale crassipes to 2.81 pg in Orchestia gammarellus, and the percentage of AT-DNA in the whole genome ranges from 56.12% in A. crassipes to 68.17% in Sardorchestia pelecaniformis. In comparison with Hyalidae, Talitridae show more uniformity in chromosome number and karyotype formula, and have larger genomes. There is a direct correlation between total DNA content and the amount of C-heterochromatic DNA. The cytogenetical data on Talitrida were compared from a phylogenetic and an evolutional point of view. The increase in genome size during the evolution of the Talitrida possibly had a role in their adaptation to supralittoral life and extreme subaerial conditions. |
The role of plant phenology in the host specificity of Gephyraulus raphanistri (Diptera: Cecidomyiidae) associated with Raphanus spp. (Brassicaceae)Janine VITOU, Marcela SKUHRAVÁ, Václav SKUHRAVÝ, John K. SCOTT, Andy W. SHEPPARDEur. J. Entomol. 105 (1): 113-119, 2008 | DOI: 10.14411/eje.2008.016 Recent host records for Gephyraulus raphanistri (Kieffer), a flower-gall midge, show restriction to Raphanus raphanistrum throughout Europe. Gephyraulus raphanistri has never been reported infesting commercially grown Brassica crops. Historical records showing a broad host range appear to have resulted from confusion with new or as yet undescribed Gephyraulus spp. and Contarinia nasturtii (Kieffer), a known gall-former of Brassica and other related genera. This study tested host specificity of G. raphanistri in the field in Europe by manipulating host plant phenology of actual and potential hosts in the genera Raphanus and Brassica as part of a risk assessment of the insect as a potential biological control agent of R. raphanistrum, one of the most important weeds of crops in Australia. Raphanus raphanistrum raphanistrum (wild radish), R. raphanistrum landra (coastal wild radish), Raphanus sativus (radish) and Brassica napus (oilseed rape cultivar) were phenologically synchronised for initial flowering and planted out in a flowering time and species block design near a natural population of R. r. landra hosting a natural population of G. raphanistri. Three generation peaks in gall formation were observed in the experiment, with galls developing on all test plants with an apparent preference for R. r. landra. The high field specificity of this gall midge is driven by the synchrony of oviposition and flower availability, not host physiological incompatibility or behavioural unacceptability. Commercially grown Brassica spp. are not suitable hosts for G. raphanistri because in the field they differ in flowering phenology from Raphanus raphanistrum. The overlap in the flowering phenology of the crop and weed in Australia makes this insect unsuitable as a biological control agent. |
Patch size and connectivity influence the population turnover of the threatened chequered blue butterfly, Scolitantides orion (Lepidoptera: Lycaenidae)Atte KOMONEN, Tuuli TIKKAMÄKI, Niina MATTILA, Janne S. KOTIAHOEur. J. Entomol. 105 (1): 131-136, 2008 | DOI: 10.14411/eje.2008.018 Chequered blue butterfly, Scolitantides orion (Lepidoptera: Lycaenidae) has severely declined in many parts of Europe and is currently red-listed in many countries. We studied the population structure and turnover of the species in a lake-island system in a National Park in eastern Finland over a three-year period. The incidence of the chequered blue on the suitable islands (n = 41) and habitat patches (n = 123) was high: an average of 82% of the islands and patches were occupied over the three year period. At the island scale, the annual population turnover rate was 17%, with an extinction and colonization rate of 7% and 10%, respectively. At the patch scale, the annual population turnover was 16%, with 7% extinction and 9% colonization rate. Islands that were occupied over the three year period had a larger area of suitable habitat than islands in which turnover events were observed. At the patch scale, turnover events were observed in small and poorly connected patches. Patchy occurrence of the host plant and observed extinction-colonization dynamics suggest that the chequered blue population confirms a metapopulation structure. Although the local populations are small, the observed high patch occupancy and balanced population turnover indicates that the metapopulation is not in immediate risk of extinction. |
Male territorial behaviour of the endemic large carpenter bee, Xylocopa (Koptortosoma) ogasawarensis (Hymenoptera: Apidae), on the oceanic Ogasawara IslandsShinji SUGIURAEur. J. Entomol. 105 (1): 153-157, 2008 | DOI: 10.14411/eje.2008.021 The endemic large carpenter bee, Xylocopa (Koptortosoma) ogasawarensis Matsumura (Hymenoptera: Apidae), on the oceanic Ogasawara (Bonin) Islands, located in the northwestern Pacific Ocean, approximately 1000 km south of the Japanese mainland, is a generalist flower visitor. Although the flower-visiting behaviour of X. ogasawarensis females has been frequently recorded, the behaviour of the males in this species has rarely been studied. I observed the territorial behaviour of males on flowers of the native plant species Scaevola sericea Vahl (Campanulales: Goodeniaceae) in a coastal area of Hahajima in early July 2007. Each male chose a particular inflorescence, hovered near it (mean distance, 239 mm from the inflorescence) and patrolled around it for several minutes (mean time, 331 s). Therefore, X. ogasawarensis males exhibit resource-based (i.e., flowers) territoriality. Males frequently attacked other males when defending their territories. However, males did not defend their territories against flower visitors of other species (i.e., introduced honeybees). Therefore, male territorial behaviour in X. ogasawarensis may be related to intrasexual competition for sites visited by females. This is the first report describing the male territorial behaviour of X. ogasawarensis. |
Flightless Hawaiian Hemerobiidae (Neuroptera): Comparative morphology and biology of a brachypterous species, its macropterous relative and intermediate formsCatherine A. TAUBER, Maurice J. TAUBER, Jon G. GIFFINEur. J. Entomol. 104 (4): 787-800, 2007 | DOI: 10.14411/eje.2007.100 Five flightless species of Micromus are known from the Hawaiian Archipelago; only one, the rare Micromus usingeri, is reported from the Island of Hawai'i. Herein, we report the natural occurrence of intermediates between this brachypterous species and its near relative, the macropterous Micromus longispinosus. We compare some morphological and life-history characteristics of the two species and the intermediates. Our study shows that: (1) The two closely related species are broadly distributed on Hawai'i, but they appear to be allopatric altitudinally. (2) M. usingeri is associated with a cool, misty, high-altitude environment, M. longispinosus with warmer, rainy conditions at lower elevations. The intermediates occur in both types of situations and generally at intermediate elevations. (3) The macropterous M. longispinosus has large, oblong, flexible, membranous forewings and hind wings. In contrast, the brachypterous M. usingeri has convex, shortened, elytra-like forewings with reticulate venation, and very small, thick, triangular, stub-like hind wings with greatly reduced venation. The wings of intermediate specimens exhibit a broad range of variation between the two species. (4) Several characteristics of wing venation are highly correlated with reduced wing size; others are not. (5) Aside from the wings, adults of M. usingeri and M. longispinosus differ in relatively few morphological features, most notably the antennal and metatibial length, prothoracic length, mesothoracic length and width, and the length of the spine-covered process on the posteroventral margin of the male T9+ectoproct. The intermediate specimens are variable in adult characteristics, but they generally fall between the two species. (6) Egg size and larval characteristics (except the body length of the fully-fed first and third instars) do not differ between the two species. (7) The evolution of the wing variation is discussed. |
Revision of New World Loxocera (Diptera: Psilidae), with phylogenetic redefinition of Holarctic subgenera and species groupsMatthias BUCK, Stephen A. MARSHALLEur. J. Entomol. 103 (1): 193-219, 2006 | DOI: 10.14411/eje.2006.022 The New World species of Loxocera Meigen are revised including two new species, L. (Imantimyia) ignyodactyla Buck sp. n. from Costa Rica (first record of the genus from the Neotropical region) and L. (Imantimyia) ojibwayensis Buck sp. n. from Ontario, Canada. Loxocera californica Capelle is synonymized with L. collaris Loew and lectotypes are designated for L. pleuritica Loew and L. cylindrica var. obsoleta Johnson (both synonyms of L. cylindrica Say). The New World species are diagnosed and a key to species is provided. The male and female terminalia of Loxocera are described in detail for the first time, and their functional morphology is discussed. Eggs of most species are described and a key to the known eggs of Loxocera is provided. A phylogenetic framework for the Holarctic subgenera and species groups of Loxocera is developed based on morphological characters of the adult flies. The Old World subgenus Platystyla Macquart is synonymized with Loxocera s. str., and Imantimyia Frey is reinstated as a valid subgenus including all Holarctic species previously placed in Loxocera s. str. except the L. aristata species group. This leads to the following new subgeneric combinations: L. (L.) malaisei Frey comb. n., L. (L.) matsumurai Iwasa comb. n., L. (L.) monstrata Iwasa, comb. n., and L. (L.) omei Shatalkin comb. n. The species groups of Imantimyia are redefined, i.e. the L. achaeta-group (7 spp.), the L. fulviventris-group (4 spp.), and the L. albiseta-group (1 sp.). The Oriental subgenus Asiopsila Shatalkin is referred to Psila Meigen s. l. as a subgenus based on characters of the egg, resulting in fourteen new generic combinations: Psila (Asiopsila) brevibuccata (Shatalkin) comb. n., P. (A.) burmanica (Frey) comb. n., P. (A.) decorata (de Meijere) comb. n., P. (A.) derivata (Shatalkin) comb. n., P. (A.) formosana (Hennig) comb. n., P. (A.) freidbergi (Shatalkin) comb. n., P. (A.) humeralis (de Meijere) comb. n., P. (A.) kambaitensis (Frey) comb. n., P. (A.) limpida (Shatalkin) comb. n., P. (A.) maculipennis (Hendel) comb. n., P. (A.) michelseni (Shatalkin) comb. n., P. (A.) pleuralis (Frey) comb. n., P. (A.) primigena (Shatalkin) comb. n., and P. (A.) vittipleura (Shatalkin) comb. n. |
Western flower thrips (Thysanoptera: Thripidae) preference for thrips-damaged leaves over fresh leaves enables uptake of symbiotic gut bacteriaEgbert J. DE VRIES, Rutger A. VOS, Gerrit JACOBS, Hans A.J. BREEUWEREur. J. Entomol. 103 (4): 779-786, 2006 | DOI: 10.14411/eje.2006.106 To understand the evolution of insect gut symbionts it is important to determine how they are passed on to the next generation. We studied this process in Erwinia species bacteria that inhabit the gut of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This is a polyphagous herbivore and a world-wide pest in agricultural crops. With bacteria in the gut, the thrips larval development time can be shorter and its oviposition rate higher compared to bacteria-free thrips. Bacteria are not directly transmitted from mother to offspring, but larvae acquire bacteria from the leaves right after they hatch. These gut bacteria are present on the leaves on feeding sites used by other thrips before the larvae arrive, probably because these other thrips have deposited bacteria via faeces or regurgitation. In this study we addressed the question whether the transmission route of symbiotic bacteria influences the thrips feeding behaviour, and determined the feeding and oviposition preference of thrips, by giving them a choice between leaves with and leaves without prior grazing by other western flower thrips. This was studied for thrips with and thrips without gut bacteria. Young larvae prefer to feed on leaves that where grazed before by other thrips and females prefer to oviposit on these grazed leaves. These results are in contradiction to earlier studies that have found that thrips larvae fitness is lower on thrips damaged plants than on clean plants. This behaviour does however promote the establishment of gut bacteria in the thrips. The factors determining the preference for thrips-damaged leaves may be the physical leaf damage or odours that are produced by the plant, the bacteria or both. |
The impact of male-killing bacteria on the evolution of aphidophagous coccinellidsMichael E.N. MAJERUSEur. J. Entomol. 103 (1): 1-7, 2006 | DOI: 10.14411/eje.2006.001 Many aphidophagous coccinellids harbour male-killing bacteria. These maternally inherited bacteria kill males early in embryogenesis, female offspring of infected mothers gaining a large resource advantage from the consumption of their dead brothers. In this paper, the diversity of male-killing bacteria and their coccinellid hosts will be briefly reviewed. Thereafter, the impact that invasion by male-killers has on coccinellid hosts will be addressed in two ways. First, the selective effects due to the loss of male progeny, and the intra-genomic conflict resulting from the cytoplasmic inheritance of the bacteria will be considered. Reductions in mitochondrial diversity, effects on clutch sizes and the evolution of male-killer suppresser systems will be discussed. Second, the impact of female biased population sex ratios on the evolution of reproductive strategies and the primary sex ratio will be investigated. Preliminary results suggesting changes in male investment per copulation, reductions in female testing behaviour of males, and male biases in the progenic sex ratios of some uninfected male lines will be presented. Avenues for future work will be outlined. |
Revision of the genus Teratolytta (Coleoptera: Meloidae)Marco A. BOLOGNA, Andrea DI GIULIOEur. J. Entomol. 103 (1): 137-161, 2006 | DOI: 10.14411/eje.2006.019 The blister beetle genus Teratolytta, belonging to the tribe Lyttini, is revised and a classification is proposed. Two main sections of the genus - one including five groups of species and the other three groups - are tentatively defined. Four new species from Eastern and Southern Anatolia are described (T. carlae sp. n., T. dvoraki sp. n., T. monticola sp. n., T. taurica sp. n.), and a key to the 17 recognized species is proposed. A diagnosis of the species as well as taxonomic remarks are proposed, and a catalogue of localities is presented. In particular, Teratolytta tricolor (Haag-Rutenberg, 1880) comb. n. is re-established as a distinct species, T. cooensis G. Müller, 1936 is confirmed as a synonym of T. gentilis (Frivaldszky, 1877), T. bytinskii Kaszab, 1957 as a synonym of T. senilis (Abeille de Perrin, 1895), and T. holzschuhi Dvořák, 1983 is proposed as a synonym of T. eylandti Semenow, 1894; some infraspecific forms are referred to the variability of T. gentilis and T. flavipes (Mulsant & Rey, 1858). The first instar larva of T. gentilis is described and figured, and the sexual behaviour of this species is also briefly studied. |
Berchmansus elegans (Neuroptera: Chrysopidae): Larval and adult characteristics and new tribal affiliationCatherine A. TAUBER, Maurice J. TAUBER, Gilberto S. ALBUQUERQUEEur. J. Entomol. 103 (1): 221-231, 2006 | DOI: 10.14411/eje.2006.024 The genus Berchmansus Navás, which was previously assigned to the tribe Leucochrysini, consists of three very rare species, all described from the Neotropics and all poorly known. Our report (1) provides the first description of a Berchmansus larva, the first instar of Berchmansus elegans (Guérin Méneville), (2) illustrates and redescribes the B. elegans adult, with emphasis on male and female genitalia, and (3) examines the larval and adult characters vis-à-vis the tribal affiliation of the genus. Given that the B. elegans adult and first instar share many apomorphies with other belonopterygine genera, this species belongs in the cosmopolitan tribe Belonopterygini, rather than the New World tribe Leucochrysini. Although Berchmansus larvae have not been collected in the field, we suspect that, like other belonopterygines, they are associated with ant nests. B. elegans exhibits a number of highly modified and unusual structures, some of which (#1 to #5) are not reported for any other chrysopids. Specifically: Males have (1) a unique, quadrate, dome-like hood above the gonarcus and (2) large, coiled parameres on the gonosaccus. First instars have (3) a greatly enlarged subapical seta on the flagellum, (4) a transverse row of long, hooked setae along the dorso-anterior margin of the pronotum, and (5) setose laterodorsal tubercles on the meso- and metathorax, with (6) multi-pronged, hooked setae. |
Abundance of mycophagous arthropods present on different species of fungi in relation to resource abundance at different spatial scalesKazuo H. TAKAHASHI, Nobuko TUNO, Takashi KAGAYAEur. J. Entomol. 102 (1): 39-46, 2005 | DOI: 10.14411/eje.2005.006 The abundance of Coleoptera, Diptera and Collembola on different species of fungi was investigated in relation to the size and abundance of fungal resources at different spatial scales; i.e., the size of the fungal fruiting body, the quality of resource in terms of number of conspecific sporophores growing within a radius of 50 cm, crowding of the clumps of fruiting bodies, and the quality of resource within a plot (20 m × 30 m). Multiple linear regression analyses showed that the influential spatial scale varied among the arthropod orders. The amount of resource at the scale of a clump made a significant contribution to the abundance of Coleoptera, and the fruiting body size significantly affected the abundance of Diptera on each fungal species. Collembolan abundance was significantly affected by the crowding of the clumps of fruiting bodies and the number of fruiting bodies per plot. These results suggest that the spatial distribution of fungal fruiting bodies may determine whether they are selected by arthropods visited. |



