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Results 1531 to 1560 of 1601:

Larvae of Bembidiini (Coleoptera: Carabidae): Subtribes Tachyina and Xystosomina

Vasily V. GREBENNIKOV, David R. MADDISON

Eur. J. Entomol. 97 (2): 223-240, 2000 | DOI: 10.14411/eje.2000.040

Larvae of 13 species of the bembidiine subtribes Tachyina (the genera Tachyta Kirby, Tachys Dejean, Polyderis Motschulsky, Elaphropus Motschulsky, Sphaerotachys G. Müller, Paratachys Casey, Porotachys Netolitzky) and Xystosomina (the genus Mioptachys Bates) were studied. Larvae of all studied taxa are described, diagnosed and illustrated. A key to genera is provided separately for the first- and older-instar larvae. Monophyly and phylogenetic position of the subtribes and genera are discussed on the basis of presumably apomorphic character states of larvae. Based on at least six synapomorphic character states the subtribes Tachyina and Xystosomina appear to form a monophyletic group. On the other hand, there are no synapomorphies to propose a sister-group relationship between Tachyina and Xystosomina within the supertribe Trechitae.

Parameters of reproductive activity in females of Harmonia axyridis (Coleoptera: Coccinellidae)

George J. STATHAS, Panagiotis A. ELIOPOULOS, Dimitrios C. KONTODIMAS, John GIANNOPAPAS

Eur. J. Entomol. 98 (4): 547-549, 2001 | DOI: 10.14411/eje.2001.069

The effects of temperatures of 15, 20, 25 and 30°C on the duration of premating and preoviposition periods of Harmonia axyridis reared on the aphid Aphis fabae, were compared in the laboratory. The course of oviposition was monitored at 25°C in females reared on Aphis fabae and the peak of egg laying was recorded at the age of 15 to 45 days. The size of egg groups (batch size), as well as daily and total fecundity was recorded. Half of the total number of eggs was laid in batches of 10-30 eggs. The mean daily and total fecundity reached a maximum of 42 and 1,641.6 eggs, respectively. Adult females oviposited for almost their entire life.

Effect of temperature on fecundity and development of the Giant Willow Aphid, Tuberolachnus salignus (Sternorrhyncha: Aphididae)

C. Matilda COLLINS, Simon R. LEATHER

Eur. J. Entomol. 98 (2): 177-182, 2001 | DOI: 10.14411/eje.2001.033

This study investigates the thermal requirements, nymphal development rates and the fecundity of both alate and apterous adults of the giant willow aphid, Tuberolachnus salignus (Gmelin) at several temperatures. Nymphal development rate increased linearly with temperature. It was estimated that 196 ± 4 degree-days above a threshold temperature of 5.5 ± 0.3°C were required for apterae to complete development from birth to final ecdysis. The alate morph was significantly less fecund than the apterous morph and its fecundity did not vary with temperature. The apterous morph displayed highest fecundity at 20°C. Survival to reproduction was lower in the alate morph, but temperature had no effect on the proportion reproducing in either morph.

Seasonal activity and reproductive biology of the ground beetle Carabus dufouri (Coleoptera: Carabidae)

Ana M. CARDENAS, Juan M. HIDALGO

Eur. J. Entomol. 97 (3): 329-338, 2000 | DOI: 10.14411/eje.2000.050

This paper concerns the life-cycle of Carabus dufouri Dejean 1829, one of the most representative species of Carabus in the south of the Iberian Peninsula. The study is based on data of the annual activity patterns in the natural habitat, on anatomical observations related to the sex and age of the specimens, on the reproductive condition of females and, finally, on the results of laboratory rearing experiments carried out to study the oviposition patterns and the course of development of immature stages. The results indicate that C. dufouri shows the annual rhythm of autumn breeders. However, the rhythm may also be related to the winter-breeder type of North Africa.

BOOK REVIEW: Bellows T.S., Fisher T.W., Caltagirone L.E., Dahlsten D.L., Gordh G. & Huffaker C.B. (eds): Handbook of Biological Control: Principles and Applications of Biological Control.

J. HAVELKA

Eur. J. Entomol. 98 (3): 413-414, 2001 | DOI: 10.14411/eje.2001.060

Academic Press, San Diego, San Francisco, New York, Boston, London, Sydney, Tokyo, 1999, 1046 pp.

Identification of Meligethes matronalis and M. subaeneus based on morphometric and ecological characters (Coleoptera: Nitidulidae)

Paolo AUDISIO, Carlo BELFIORE, Alessio DE BIASE, Gloria ANTONINI

Eur. J. Entomol. 98 (1): 87-97, 2001 | DOI: 10.14411/eje.2001.012

An analysis of morphometric and bionomic data (as well as the genetic evidence discussed in a companion paper) clearly shows that Meligethes matronalis Audisio & Spornraft, 1990 and M. subaeneus Sturm, 1845 (members of the Meligethes coracinus complex: Coleoptera, Nitidulidae, Meligethinae), recently synonymised by Kirejtshuk (1997), are distinct species. The two species are also compared with the closely related M. coracinus Sturm, 1845. Meligethes matronalis is strictly associated with Hesperis matronalis L. (Brassicaceae) in early Summer, whereas the larvae of the frequently syntopic M. subaeneus develop on Cardamine spp. (Brassicaceae) in Spring; M. coracinus is a more polyphagous species, developing from early Spring to late Summer mostly on Brassica spp., Sinapis spp., Barbarea spp. and Sisymbrium spp. (Brassicaceae).

Revision of the Australian genus Blaena (Heteroptera: Cydnidae)

Jerzy A. LIS, Joanna HEYNA

Eur. J. Entomol. 98 (3): 321-350, 2001 | DOI: 10.14411/eje.2001.055

A revision of species of the Australian burrower bug genus Blaena Walker, 1868 is presented. Eight previously known species are redescribed and four new ones, B. hirta n. sp. (Queensland), B. parathroposa n. sp. (Queensland), B. pseudosetosa n. sp. (Western Australia), and B. serrata n. sp. (Northern Territory, Queensland, Western Australia) are described and illustrated. The male and female genitalia of all the species of the genus are studied for the first time. A key for species determination is also provided.

Small aquatic and ripicolous bugs (Heteroptera: Nepomorpha) as predators and prey: The question of economic importance

Miroslav PAPÁČEK

Eur. J. Entomol. 98 (1): 1-12, 2001 | DOI: 10.14411/eje.2001.001

Some features of the biology and feeding relationships of small waterbugs (Notonectidae, Corixidae, Pleidae, Helotrephidae, Aphelocheiridae) and ripicolous bugs (Gelastocoridae, Ochteridae) are reviewed. Individual families are discussed as predators or as prey of other animals. Special attention is given to characteristics and relationships that affect human beings directly or indirectly. The most important relationships from the economic point of view are: bugs and blood-sucking Diptera, bugs and fish, bugs and some endangered or protected amphibians and water birds. Of less importance is the occasional use of some aquatic bugs as saprobity bioindicators. It seems that the economic importance of these bugs has been underestimated.

A possible role for the dorsolateral protocerebral neurosecretory neurons in the trophic adaptations of Lymantria dispar (Lepidoptera: Lymantriidae)

Vesna PERIĆ-MATARUGA, Jelica LAZAREVIĆ, Vera NENADOVIĆ

Eur. J. Entomol. 98 (3): 257-264, 2001 | DOI: 10.14411/eje.2001.042

The activity and number of protocerebral neurosecretory neurons of the dorsolateral group (L1, L2 and L2'), as well as the size of the corpora allata were investigated in 5th instar larvae of the gypsy moth (Lymantria dispar) from two populations (oak and locust-tree forests) fed one of two host-plants (oak is a suitable and locust-tree an unsuitable host-plant).
The monitoring of activity related cytological parameters and the number of protocerebral dorsolateral neurosecretory neurons revealed that differently adapted populations respond to nutritive stress differently. The activity of the L1 neurosecretory neurons in the protocerebra of the caterpillars is low in those from the locust-tree forest regardless of host-plant quality. The L2 neurosecretory neurons in the oak population become active when they were fed the unsuitable host-plant whereas their activity was high in locust-tree caterpillars regardless of the host-plant. A decrease in the number of neurosecretory neurons in a response to a novel food was noticed in both populations. The activity of the L2' neurosecretory neurons was similar in all caterpillars, but their number was increased in those from the locust-tree forest. The corpora allata of the locust-tree caterpillars were large whereas those of the oak forest caterpillars only increased in size when they were fed locust-tree leaves.
It is obvious that nutritive stress results in neurosecretory reorganization and changes in the titre of hormones that modulate the morphogenetic programme.

Oviposition responses of aphidophagous coccinellids to tracks of ladybird (Coleoptera: Coccinellidae) and lacewing (Neuroptera: Chrysopidae) larvae

Zdeněk RŮŽIČKA

Eur. J. Entomol. 98 (2): 183-188, 2001 | DOI: 10.14411/eje.2001.034

The effects of oviposition-deterring larval tracks of four aphidophagous coccinellids and two chrysopids were investigated on females of four coccinellid species in choice tests. Aphidophagous coccinellids Cycloneda limbifer Casey, Semiadalia undecimnotata (Schneider) and Coccinella septempunctata L. laid significantly fewer eggs on sites with tracks of unfed conspecific first instar larvae than on clean sites, but Leis dimidiata (F.) laid similar numbers of eggs on both sites.
In some but not all species, tracks of heterospecific predators also deterred coccinellid females. Interspecific effects were stronger between some allopatric species than between the sympatric coccinellids C. septempunctata and S. undecimnotata. C. limbifer laid relatively few eggs on sites previously exposed to larvae of S. undecimnotata and L. dimidiata. S. undecimnotata avoided sites with tracks of L. dimidiata larvae. The two smaller species, C. limbifer and S. undecimnotata, laid considerably fewer eggs per batch than the larger coccinellids, C. septempunctata and L. dimidiata. C. limbifer and S. undecimnotata oviposited similar numbers of eggs on clean sites and sites with tracks of chrysopid larvae of the species Chrysopa oculata and Chrysopa perla. Females of C. septempunctata laid fewer eggs on sites previously exposed to larvae of C. oculata but not C. perla.
Densities of faecal spots of coccinellid females on clean substrates and substrates with tracks of predatory larvae differed significantly in only one choice test (C. limbifer females exposed to tracks of S. undecimnotata larvae). This indicates that the presence of larval tracks affects where females lay eggs more than where they search.

Sexual activity in Coccinellidae (Coleoptera): a review

Ivo HODEK, Piotr CERYNGIER

Eur. J. Entomol. 97 (4): 449-456, 2000 | DOI: 10.14411/eje.2000.069

Although there are few studies of the sexual life of coccinellids these phenomena have attracted the interest of isolated groups of coccinellidologists. Probably the most important finding is that at least some coccinellid species (Adalia bipunctata and Harmonia axyridis) do not mate at random with the females prefering certain males. This phenomenon was first observed in Adalia bipunctata by Lusis and then studied in detail by Majerus, O'Donald, de Jong and others. In Japan, Harmonia axyridis was similarly studied by Osawa and Ueno. While the former author found that in this species (as in A. bipunctata) the colour of the elytra is most important in mate choice by females, the latter stresses that size and activity are important. Sperm competition is another interesting phenomenon, most often the sperm of the last male fertilizes the eggs (Ueno, Katakura). Obata and Hidaka have contributed in an important way to elucidating the function of the spermatophore in mating. The studies by Hodek and Ceryngier recorded the maturation and regression of testicular follicles and the relation of mating activity to diapause in four coccinellid species. In contrast to females, where induction of diapause prevents maturation of ovaries, in diapausing males the tissue of testicular follicles remains active until the temperatures decrease in late autumn. Dissection of spermathecae revealed principal difference in autumn mating activity between Coccinella septempunctata, in which 40-60% of the beetles mated before hibernation and Ceratomegilla (syn. Semiadalia) undecimnotata, which does not mate in autumn.

Field observations, laboratory rearing and descriptions of immatures of the planthopper Hyalesthes obsoletus (Hemiptera: Cixiidae)

SFORZA R.*, BOURGOIN T., WILSON S.W., BOUDON-PADIEU E.

Eur. J. Entomol. 96 (4): 409-418, 1999

The cixiid planthopper Hyalesthes obsoletus Signoret is an efficient vector of the stolbur phytoplasma, the cause of various crop diseases. In the field, this monovoltine species feeds on a wide variety of woody and herbaceous plants. It overwinters as larvae on the roots of its host plants. During this study, we collected adults mainly from lavender (Lavendula angustifolia Miller), bindweed (Convolvulus arvensis L. and C. sepium L.), hoary cress (Cardaria draba L.), and occasionally from plantain (Plantago cynops L.), toadflax (Linaria striata L.), bedstraw (Galium verum L.), and mountain savory (Satureia montana L.). Fertility of field collected females from sites at two different elevations differed significantly. Fertility at 300 m (50.6 eggs per female; N = 28) was more than twice that at 900 m (22.8 eggs per female; N = 19). Only one specimen of the species was found to be parasitized by an undetermined species of Dryinidae (Hymenoptera). H. obsoletus was reared in controlled conditions on lavender. Unlike in the field, larvae developed in the laboratory at the base of the host plant and on basal shoots. Egg incubation averaged 7 ± 1.2 weeks (N = 10). Total development time from egg to adult averaged 27 ± 4 weeks (N = 5) on lavender. A morphological description of the five instars is provided. The study was supplemented by scanning electron microscopy. Particular attention was paid to the structure of the wax-plates and the absence of compound eyes in the early larval stages.

Carabid beetles (Coleoptera: Carabidae) and habitat fragmentation: a review

Jari NIEMELÄ

Eur. J. Entomol. 98 (2): 127-132, 2001 | DOI: 10.14411/eje.2001.023

I review the effects of habitat fragmentation on carabid beetles (Coleoptera, Carabidae) and examine whether the taxon could be used as an indicator of fragmentation. Related to this, I study the conservation needs of carabids. The reviewed studies showed that habitat fragmentation affects carabid assemblages. Many species that require habitat types found in interiors of fragments are threatened by fragmentation. On the other hand, the species composition of small fragments of habitat (up to a few hectares) is often altered by species invading from the surroundings. Recommendations for mitigating these adverse effects include maintenance of large habitat patches and connections between them. Furthermore, landscape homogenisation should be avoided by maintaining heterogeneity of habitat types. It appears that at least in the Northern Hemisphere there is enough data about carabids for them to be fruitfully used to signal changes in land use practices. Many carabid species have been classified as threatened. Maintenance of the red-listed carabids in the landscape requires species-specific or assemblage-specific measures.

Phylogenetic relationships between the European and Asian eight spined larch bark beetle populations (Coleoptera, Scolytidae) inferred from DNA sequences and fungal associates

Christian STAUFFER, Thomas KIRISITS, Christa NUSSBAUMER, Roman PAVLIN, Michael J. WINGFIELD

Eur. J. Entomol. 98 (1): 99-105, 2001 | DOI: 10.14411/eje.2001.014

The eight spined larch bark beetles infest various species of Larix in Europe and Asia. Ips cembrae is the only Ips species with larch as its main host. Ips subelongatus, Ips fallax, Ips shinanonensis and Ips cembrae var. engadinensis are treated as synonyms of I. cembrae. These three putative species and the one variety are distinguished by their host tree and geographic distribution, as it is not possible to distinguish them on the basis of morphological differences. Beetles were collected from European and Asian populations, and from hosts and geographic areas where the species were first found and described and in their natural ranges of distribution. These beetles were used to study the phylogenetic relationships of the eight spined larch bark beetles. A region of the mitochondrial gene was analysed and the blue-stain fungi associated with I. cembrae in Europe were investigated and compared with those recorded as associated with the larch bark beetle in Japan. Only minor sequence differences were detected between the populations in Europe and Asia. However, the European populations differed by 4.3% from the Asian populations. The phylogenetic analysis placed the European and Asian haplotypes in significantly distinct clusters. This distinction was supported by the finding of an insertion/deletion in a non-coding region of the mitochondrial DNA. Furthermore, there are differences in the fungi associated with the eight spined larch bark beetles in Europe and Japan. The results suggest that the I. cembrae complex contains at least two taxa: I. cembrae infesting larch in Europe and I. subelongatus infesting larch in Asia.

Seven new montane species of Drosophila in the Eastern Arc mountains and Mt Kilimanjaro in Tanzania attesting to past connections between eastern and western African mountains (Diptera: Drosophilidae)

Daniel LACHAISE, Marie-Therese CHASSAGNARD

Eur. J. Entomol. 98 (3): 351-366, 2001 | DOI: 10.14411/eje.2001.056

This report describes 7 new species of Drosophila found in the Eastern Arc mountains and on Mount Kilimanjaro in Tanzania: D. baucipyga, D. gata, D. kilimanjarica, D. neogata, D. paragata, D. pilocornuta and D. usambarensis spp.n. Two new species complexes, the megapyga species complex (Sophophora subgenus, melanogaster group, montium subgroup) and the gata species complex (Drosophila subgenus) are introduced. Only one species, D. baucipyga of the montium subgroup, has a geographical range matching the whole Eastern Arc, from the Usambara Mts. in the north-east of Tanzania to Mt. Uzungwa in the south-south west of the country. Five others, including one representative of the dentissima group of the Sophophora subgenus, D. usambarensis, and four representatives of the Drosophila subgenus, D. gata, D. neogata, D. paragata and D. pilocornuta, were found only in the Usambara Mts. Two of these five, D. usambarensis and D. pilocornuta were found only in West-Usambara, while two other related species, D. gata and D. paragata, were found only in East-Usambara. Only the distribution of D. neogata covers the whole of the Usambara mountains. Outside the Eastern Arc, another representative of the dentissima group, D. kilimanjarica, was found only on Mount Kilimanjaro. This new, highly specific, montane fauna of Drosophila further contributes to the unique biological diversity of the Eastern Arc Mts. The biogeographic affinities of the new taxa suggest past connections with the Virunga and Ruwenzori ranges and further west with the Cameroon Volcanic Line. It indicates, in particular, that the Eastern Arc forests have passed through a succession of coalescence and fragmentation events.

Cladistic systematics of the genus Amphimallon (Coleoptera: Scarabaeidae: Melolonthinae)

Olivier MONTREUIL

Eur. J. Entomol. 97 (2): 253-270, 2000 | DOI: 10.14411/eje.2000.042

A phylogeny of fifty-eight cockchafer species belonging to the genus Amphimallon Berthold, 1827 is proposed, based on sixty-five morphological characters. The cladistic analysis provides seventy-two equally parsimonious trees. The genus Amphimallon is redefined and species-groups are introduced and defined: A. pini-group (seven species), A. vernale-group (five species), A. solstitiale-group (seven species), A. arianae-group (two species), A. peropacum-group (one species), A. fuscum-group (eleven species), A. naceyroi-group (seven species), A. majale group (five species), A. lusitanicum-group (six species). Other species previously placed in Amphimallon are considered species incertae sedis in this paper: amphibolum Peyerimhoff, 1949, and a monophyletic group composed of six North African species: altifrons Baraud, 1971, julieni Baraud, 1972, melillanum Baraud, 1972, scutellare Lucas, 1846, subcristatum Fairmaire, 1879, subparallelum Escalera, 1913. Four new Amphimallon species are described: A. adanense sp. n. from Turkey, A. maniense sp. n. from Greece, A. jeannae sp. n. and A. safiense sp. n. from Morocco. The following taxonomic conclusions are proposed: A. seidlitzi Brenske, 1891 = A. trisinuatum Reitter, 1902 syn. n.; Amphimallon jeannei (Baraud, 1971) comb. n.; Miltotrogus caucasicus Gyllenhal, 1817 comb. n.; Amphimallon vernale (Brullé, 1832) stat. n.; A. furvum (Germar, 1817) stat. n.; A. javeti Stierlin, 1864 stat. n.

A gypsy moth (Lymantria dispar, Lepidoptera: Lymantriidae) multinucleocapsid nuclear polyhedrosis virus from France: comparison with a North American and a Korean strain

Neelam NARANG, Franck HÉRARD, Edward M. DOUGHERTY, Kim CHEN, Fernando E. VEGA

Eur. J. Entomol. 98 (2): 189-194, 2001 | DOI: 10.14411/eje.2001.035

As part of a search for natural enemies of the gypsy moth (Lymantria dispar), virus-infected samples were collected near Toulouse, France. Light and electron microscope studies confirmed that the French strain is a multinucleocapsid nuclear polyhedrosis virus (MNPV). In vivo bioassays using the New Jersey strain of L. dispar, and comparing L. dispar MNPV (LdMNPV) strains from France, North America and Korea, showed that the French strain was the least active, whereas the North American strain had the highest activity. The viral efficacy of all strains was enhanced 200 to 1300-fold in the presence of 1% fluorescent brightener. The enhancement was highest in the American strain and lowest in the French strain. French LdMNPV (LdMNPVF) DNA cut with four restriction enzymes (BamHI, EcoRI, HindIII, and NotI) revealed minor fragment size differences, but many similarities when compared to the North American and the Korean strain. PCR amplification of a LdMNPV early gene (G22) was detected in the North American and the Korean strain, but not in the French strain.

Morphology of invasion: body size patterns associated with establishment of Coccinella septempunctata in western North America

Edward W. EVANS

Eur. J. Entomol. 97 (4): 469-474, 2000 | DOI: 10.14411/eje.2000.072

The Old World ladybird Coccinella septempunctata has rapidly established itself as an abundant, widespread species throughout North America. Overwintering individuals of this species, and of native ladybirds, were collected from early season alfalfa in northern Utah during the period of initial establishment of the invader (1989 to 1999), and were measured for body size. Adult body size can vary widely within insect species, often reflecting differential success of individuals as immatures in obtaining food. Here I examine patterns of ladybird body size to address two questions associated with the establishment of C. septempunctata: (1) is there evidence for adverse impact on native species?, and (2) why has the invader has been so successful in establishment? As an indirect test of adverse competitive effect of the invader on native species, I determined whether mean body size of adults of the five most common native species (Coccinella tranversoguttata, Hippodamia convergens, H. quinquesignata, H. sinuata, and H. tredecimpunctata) declined over the period 1991-1997 as the invader increased rapidly in abundance. No such decline was observed for any of these species, thus providing no evidence that the invader's establishment has significantly increased scramble competition for food among immature ladybirds. I also compared body size distribution of the invading species with that of native species. The invader was distinctive in having particularly large variation in body size among individuals (i.e., in having relatively high proportions of both unusually large and small individuals). Such results are consistent with the hypothesis that the invader's success derives from being a generalist with much "ecological flexibility" in regard to the conditions under which it engages and succeeds in reproduction.

Ecdysone 20-hydroxylation in Manduca sexta (Lepidoptera: Sphingidae) midgut: Development-related changes of mitochondrial and microsomal ecdysone 20-monooxygenase activities in the fifth larval instar

WEIRICH G.

Eur. J. Entomol. 94 (1): 57-65, 1997

In the mid fifth-larval-instar tobacco hornworm, Manduca sexta, the midgut has high ecdysone 20-monooxygenase (E20MO) activity, with a peak at the onset of wandering on day five. Activities of E20MO, present both in mitochondria and in microsomes, were determined around the time of the peak. During the day preceding the peak the microsomal E20MO increased 60-fold (total activity) or 115-fold (specific activity), and it decreased to one half or less of the peak activities within two days after the peak. The mitochondrial E20MO increased only 1.3 to 2.4-fold (total and specific activities, respectively) before the peak, but declined more rapidly than the microsomal E20MO after the peak. It is concluded that mitochondrial and microsomal E20MO activities are controlled independently and that changes in the physiological rate of ecdysone 20-hydroxylation are effected primarily by changes of the microsomal E20MO activities.

Book Review: Three recent volumes on insects in the Zoological Catalogue of Australia.

STYS P.

Eur. J. Entomol. 95 (1): 63-64, 1998

Cassis G. & Gordon G. 1995: Hemiptera: Heteroptera (Coleorrhyncha to Cimicomorpha). In Houston W.W.K. & Maynard G.V. (eds): Zoological Catalogue of Australia. Vol. 27.3A. CSIRO Melbourne, xv + 506 pp.

Wells A. 1996 (ed.):  Zoological Catalogue of Australia. Vol. 26. Psocoptera, Phthiraptera, Thysanoptera. CSIRO, Melbourne, xiii + 418 pp.
Wells A. 1996 (ed.):  Zoological Catalogue of Australia. Vol. 28. Neuroptera, Strepsiptera, Mecoptera, Siphonaptera. CSIRO Melbourne, xii + 230 pp.

Bionomics and ecology of Bemisia tabaci (Sternorrhyncha: Aleyrodidae) in Italy

BOSCO D., CACIAGLI P.

Eur. J. Entomol. 95 (4): 519-527, 1998

The development of a B-biotype Bemisia tabaci Italian colony was studied on bean at 9 constant temperatures (15, 16, 17, 20, 23, 26, 29, 32, 35°C). The developmental time from egg-to-adult varied from 70 days at 16°C to 22 at 26°C and higher temperatures. A thermal requirement for egg-to-adult development of 307 day-degrees was calculated, based on a lower developmental threshold of 11.53°C. The survival of egg, nymph and adult whiteflies was investigated at 0, 2, 4, and 6°C on broad bean for periods of 1-8 days. The adult was the most cold-sensitive stage, while the egg and nymph showed a similar level of cold resistance. The effect of sub-lethal cold stress of 4-8 days at 4°C on eggs and nymphs was studied. After exposure to low temperatures, whiteflies needed longer developmental times, from 5 to 8 days more. The presence of B. tabaci under outdoor conditions in Italy was investigated with field surveys and correlated with climatic data; the whitefly species was found in open field conditions only south of the 41° parallel, in areas characterised by less than 5 frost days per winter and by annual mean temperatures >16°C.

Book Review: Medical Entomology for Students.

DUSBABEK F.

Eur. J. Entomol. 95 (2): 210, 1998

Service M.W.: Medical Entomology for Students. Chapman & Hall, London, 1996, 278 pp.

Effects of structural heterogeneity of a laboratory arena on the movement patterns of adult Eriopis connexa and Hippodamia variegata (Coleoptera: Coccinellidae)

Audrey A. GREZ, Paula VILLAGRÁN

Eur. J. Entomol. 97 (4): 563-566, 2000 | DOI: 10.14411/eje.2000.088

We asked if the structural heterogeneity of a laboratory arena differentially affected the abandonment of the plot, residence time, locomotory rate, pause duration and turning rate of adult Eriopis connexa and Hippodamia variegata (Coleoptera: Coccinellidae). We simulated an increase in heterogeneity by distributing vertically-oriented toothpicks in a circular arena: one control (without toothpicks), one uniform plot (toothpicks every 1 cm) and one random plot (randomly distributed toothpicks). No food was provided inside the arena. Coccinellids were released individually in the centre of each plot and their movement was videotaped. Fewer H. variegata adults left the plots as these become more heterogeneous. E. connexa did not discriminate between plots in their residence time, but H. variegata remained longer in the uniform and longest in the random plots. H. variegata only stayed longer than E. connexa in the random plots. This resulted because adults of H. variegata were stationary for longer periods, moved more slowly and less linearly and explored a higher number of toothpicks than adults of E. connexa in more heterogeneous environments. Thus, the physical structure of the environment differentially affects the movement patterns of insects. Eriopis connexa seems to be less sensitive to structural heterogeneity than H. variegata.

Adaptive preferential selection of young coccinellid hosts by the parasitoid wasp Dinocampus coccinellae (Hymenoptera: Braconidae)

Michael E.N. MAJERUS, Irene E. GEOGHEGAN, Tamsin M.O. MAJERUS

Eur. J. Entomol. 97 (2): 161-164, 2000 | DOI: 10.14411/eje.2000.030

Dinocampus coccinellae females which eclose in mid-summer have the opportunity to oviposit in overwintered or in newly eclosed coccinellid hosts. Given the short further longevity of overwintered hosts, offspring fitness would be increased by ovipositing preferentially in young hosts. Laboratory choice tests show that female D. coccinellae do exhibit such a preference.

Improved methods of testing and release of Aphidoletes aphidimyza (Diptera: Cecidomyiidae) for aphid control in glasshouses

Jeroen Van SCHELT, Sandra MULDER

Eur. J. Entomol. 97 (4): 511-515, 2000 | DOI: 10.14411/eje.2000.079

The gallmidge Aphidoletes aphidimyza is used commercially to control aphids infesting greenhouse crops such as sweet pepper and tomato. In this study we investigated several different ways of improving its use as a biocontrol agent. In the laboratory there was a very strong relation between the availability of spider's webs and successful mating. When mated in cages containing spider's webs a greater proportion of the females were mated and the females laid more eggs compared to the females in cages without spider's webs. As adults emerging from cocoons can crawl up through 15 cm of vermiculite it is possible to transport and release them from bottles, which can be placed open in a greenhouse instead of having to spread the material around the plants. Dispersal of adults from the bottles was measured by placing sentinel plants around a single release point. Eggs of the gallmidge were found on plants at distances up to 45 m from the release point. Intraguild predation of the eggs of the gallmidge by the mites Amblyseius degenerans and Amblyseius cucumeris was also assessed.

Description of the early stages of Anomalipus plebejus plebejulus (Coleoptera: Tenebrionidae) from Zimbabwe with notes on the classification of the Opatrinae

Dariusz IWAN, Stanislav BEČVÁŘ

Eur. J. Entomol. 97 (3): 403-412, 2000 | DOI: 10.14411/eje.2000.062

Immature stages of a South African tenebrionid beetle, account is the first modern description of the egg and first and older larval instars of the genus Anomalipus and the subtribe Anomalipina. The significance of larval characters of Anomalipus and other relevant taxa for classification of the subfamily Opatrinae sensu Medvedev (1968) [= "opatrine lineage: Opatrini" sensu Doyen & Tschinkel (1982)] are discussed. A synopsis of Anomalipus plebejus plebejulus Endrödy-Younga, 1988, of the tribe Platynotini are described and illustrated. This Platynotini larvae is presented.

The impact of individual ladybirds (Coccinella septempunctata, Coleoptera: Coccinellidae) on aphid colonies

Nicole MINORETTI, Wolfgang W. WEISSER

Eur. J. Entomol. 97 (4): 475-479, 2000 | DOI: 10.14411/eje.2000.073

Pea aphids (Acyrthosiphon pisum) have been reported to produce winged offspring in the presence of predatory ladybirds. These offspring may leave host plants by flight after they have developed into winged adults. The inter-generational nature of this response raises the question about the chances of survival of aphids developing in attacked colonies. We studied the behaviour of predatory ladybirds on host plants by releasing adult 7-spot ladybirds (Coccinella septempunctata) on bean plants hosting either no prey individuals or colonies of 10 or 30 pea aphids. Interactions between predator and prey were recorded until the ladybird left the plant. Ladybird patch residence time increased with the number of aphids present on a plant but beetles generally left a plant before all aphids were eaten. The time budget of the ladybirds revealed a high proportion of time not spent in feeding activities. Predation rate was about one aphid killed per 10min residence time in both treatments with aphid-infested plants. Aphids that survived an attack by the predator or that were alarmed when a conspecific was attacked often emigrated from the host plant, and their number was of the same magnitude as the number of aphids killed by the predator. On average, pea aphid numbers at the end of an experiment were reduced to less than a third of the initial value. The results of the experiment show that attack by single ladybirds does on average not cause immediate extinction of small aphid colonies. The short patch residence times of on average less than two hours show that a predator individual that induces winged-offspring production in an aphid colony will not any longer be present in the colony when the induced offspring mature. To understand the adaptiveness of predator-induced wing development in pea aphids the probabilities of subsequent attacks on an aphid colony need to be investigated.

Egg distribution in the large copper butterfly Lycaena dispar batavus (Lepidoptera: Lycaenidae): Host plant versus habitat mediated effects

Mark R. WEBB, Andrew S. PULLIN

Eur. J. Entomol. 97 (3): 363-367, 2000 | DOI: 10.14411/eje.2000.055

The large copper butterfly, Lycaena dispar batavus, a subspecies of much conservation interest, is host-specific to the great water dock, Rumex hydrolapathum, but little is known of the relationship between herbivore and host in wild populations. This study investigated the distribution of both R. hydrolapathum plants and L. d. batavus eggs in four different habitat types within the Weerribben National Park, The Netherlands, during the summer of 1993. As expected, host plant distribution strongly influenced that of its herbivore. Further, both species had significantly aggregated distributions, and that of R. hydrolapathum was in agreement with the negative binomial model. Host plant selection for oviposition showed no significant relationship with physical plant characteristics, such as plant height and the number of leaves, and at the scale studied, habitat type was of only limited influence. The possible influence of the vegetational architecture surrounding host plants is discussed.

Revision of the Oriental genus Idiotrephes (Heteroptera: Nepomorpha: Helotrephidae)

Miroslav PAPÁČEK, Herbert ZETTEL

Eur. J. Entomol. 97 (2): 201-211, 2000 | DOI: 10.14411/eje.2000.038

The Oriental helotrephid genus Idiotrephes Lundblad, 1933, is taxonomically revised. Species discrimination is based on male genitalia and female terminalia. Three species groups are recognized. The I. chinai group contains I. chinai Lundblad, 1933 (type species; from Sumatra, Borneo, and West Malaysia) and three newly described species; I. asiaticus sp. n. (from Vietnam, Thailand, and west Malaysia); I. yupae sp. n., and I. polhemusi sp. n. (both from Thailand). The I. maior group contains I. maior Papáček, 1994; I. meszarosi Papáček, 1995 (both from Vietnam), and I. hainanensis sp. n. (from Hainan, China). The I. thai group consists of two newly described species from north and northeast Thailand, I. thai sp. n. and I. shepardi sp. n. In addition, some features of biology and morphology of the ovipositor are also included.

Male calling, mating and oviposition in Isoperla curtata (Plecoptera: Perlodidae)

José Manuel TIERNO DE FIGUEROA, Julio Miguel LUZÓN-ORTEGA, Antonino SÁNCHEZ-ORTEGA

Eur. J. Entomol. 97 (2): 171-175, 2000 | DOI: 10.14411/eje.2000.032

The reproductive biology (drumming call, mating behaviour, fecundity and egg structure) of Isoperla curtata, an endemic species from the Southern Iberian Peninsula, is described. The male's mating call has a diphasic pattern, with a mean of 17.3 beats per call (range = 8-27; SD = 4.7) and a duration of 792.9 ms per call (range = 228-1312; SD = 307.9). This call differs from that of other species of Isoperla in having two distinct phases with different millisecond intervals, and is species-specific. Mating lasts between 131 and 3864 seconds (mean = 2180.9 s and SD = 1027.8). Since males and females mate more than once (mean number of matings per female was 1.85 and per male 2.25), the species is polyandric and polygynic. The position adopted by the male during mating is different from that described for other stonefly species. Other mating behaviours are interpreted as displacement manoeuvers, tactile stimulation and possibly sexual selection by cryptic female choice. There was a statistically significant correlation between size and the number of matings in females (r = 0.849; p = 0.016), but not in males. Each female laid between one to four egg masses composed of an average of 88.7 eggs. Maximum fecundity was 319 eggs. The mean egg volume was 80.5 × 105 µm3 which is very similar to that of other Isoperla species. An outstanding morphological characteristic of the egg is the lobed outline of the chorion cells.

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