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BOOK REVIEW: Bauernfeind E. & Humpesch U.H.: Mayflies of Central Europe - Identification and Ecology (Insecta - Ephemeroptera).T. SOLDÁNEur. J. Entomol. 103 (1): 54, 2006 | DOI: 10.14411/eje.2006.008 Verlag des Naturhistorischen Museums Wien, 2001, 239 pp. ISBN 3-900-275-86-6. Price EUR 53.00. |
BOOK REVIEW: McGavin G.C.: ESSENTIAL ENTOMOLOGY. AN ORDER-BY-ORDER INTRODUCTION.T. SOLDÁNEur. J. Entomol. 103 (1): 276, 2006 | DOI: 10.14411/eje.2006.035 Oxford University Press, Oxford, 2001, vi + 318 pp. ISBN 0-19-8500025. Price GBP 18.99. |
BOOK REVIEW: Raman A., Schaefer C.W. & Withers T.M. (eds): BIOLOGY, ECOLOGY, AND EVOLUTION OF GALL-INDUCING ARTHROPODS. VOL. 1, 2.V. SKUHRAVÝ, M. SKUHRAVÁEur. J. Entomol. 103 (2): 495-496, 2006 | DOI: 10.14411/eje.2006.063 Science Publishers, Enfield (NH), USA & Plymouth, UK, 2005, xxi + 817 pp. ISBN 1-57808-262-5 (Set), 1-57808-345-1 (Vol. 1), 1-57808-346-X (Vol. 2). Price GBP 81.40. |
Are we studying too few taxa? Insights from aphidophagous ladybird beetles (Coleoptera: Coccinellidae)John J. SLOGGETTEur. J. Entomol. 102 (3): 391-398, 2005 | DOI: 10.14411/eje.2005.056 Many areas of biology employ standard model organisms on which a majority of research effort is concentrated. However, there is invariably a danger associated with the use of too few or atypical models for studies of particular taxonomic groups, guilds or biological phenomena. Using aphidophagous ladybirds, I show that in this group, in the last ten years, 69% of research has been concentrated on just five species, all generalist ecotypes. Much research is now concentrated on invasive species, originally biocontrol agents, and over half the aphidophagous ladybird work on intraguild interactions is centred on two of the five predominant species, Coccinella septempunctata and Harmonia axyridis. Using examples from differing areas of research, I show that studies of more unusual, non-commercial specialists can enhance our understanding of the commonly studied groups. I suggest further areas where a similar approach may lead to equally illuminating results. |
BOOK REVIEW: Hausmann A.: The Geometrid Moths of Europe. Volume 1.K. SPITZEREur. J. Entomol. 98 (3): 276, 2001 | DOI: 10.14411/eje.2001.044 Apollo Books, Stenstrup (DK), 2001, 282 pp. + 8 colour plates. |
BOOK REVIEW: Jong de H.: The Types of Diptera Described by J.C.H. de Meijere.M. CHVÁLAEur. J. Entomol. 98 (1): 106, 2001 | DOI: 10.14411/eje.2001.015 Backhuys Publishers, Leiden, 2000, 271 pp. |
Comparative genetic studies of native and introduced Coccinellidae in North AmericaElliot S. KRAFSUR, John J. OBRYCKI, James D. HARWOODEur. J. Entomol. 102 (3): 469-474, 2005 | DOI: 10.14411/eje.2005.067 During the past four decades, several species of aphidophagous Coccinellidae became established in North America, including Coccinella septempunctata, Harmonia axyridis, Hippodamia variegata, and Propylea quatuordecimpunctata. After their establishment, unknown circumstances favoured a rapid increase in population densities and distribution of H. axyridis and C. septempunctata at localities hundreds and thousands of kilometers from their release sites. Propylea quatuordecimpunctata and Hippodamia variegata have spread more slowly after becoming established in northeastern North America. Comparative studies based upon allozyme variation in these four introduced species and in six native North American species of ladybird beetles revealed no significant differences in genetic diversities. Genetic variation, assessed by allelic diversity and heterozygosity, was uncorrelated with the establishment and spread of these predatory species in North America. All ladybirds studied show a remarkable degree of dispersion with little detectable population subdivision. |
BOOK REVIEW: Gielis C: PTEROPHOROIDEA & ALUCITOIDEA (LEPIDOPTERA) - IN: WORLD CATALOGUE OF INSECTS 4.J. JARO©Eur. J. Entomol. 103 (2): 396, 2006 | DOI: 10.14411/eje.2006.053 Apollo Books, Stenstrup, 2003, 198 pp. ISBN 87-88757-68-4. Price DKK 320.00. |
BOOK REVIEW: Wittner M. & Weiss L.M.: The Microsporidia and Microsporidiosis.J. WEISEREur. J. Entomol. 98 (1): 124, 2001 | DOI: 10.14411/eje.2001.022 ASM- Press, Washington, 2000, 553 pp., 326 ill., 18 tab. |
Augmentation of managed populations of Osmia cornuta and O. rufa (Hymenoptera: Megachilidae) in Southeastern EuropeMiloje KRUNIĆ, Ljubiąa STANISAVLJEVIĆEur. J. Entomol. 103 (3): 695-697, 2006 | DOI: 10.14411/eje.2006.091 We describe augmentation of managed populations of Osmia cornuta and O. rufa in the vicinity of Belgrade (Serbia). Annual augmentation of O. cornuta populations was more than five-fold during the six years of our study. This was achieved by watering the soil near the Osmia augmentation shelters used for nest building. However, populations of O. rufa under the same treatment only doubled annually. Data are also presented on sex ratios in these managed populations, the sex ratio being an important factor in increasing population numbers and raising pollination efficacy. Sex ratio values (♂ : ♀) varied from 1.46 : 1 to 3.22 : 1 in the populations of O. cornuta and from 1.35 : 1 to 2.68 : 1 in those of O. rufa. |
BOOK REVIEW: Nilsson A.N. & Vondel B.J. van: Amphizoidae, Aspidytidae, Haliplidae, Noteridae and Paelobiidae (Coleoptera). In: World Catalogue of Insects, Volume 7.D.S. BOUKALEur. J. Entomol. 103 (3): 536, 2006 | DOI: 10.14411/eje.2006.070 Apollo Books, Stenstrup, Denmark, 2005, 171 pp. ISBN 87-88757-49-8. Price excluding postage DKK 320 from the publisher. |
Sex ratio shift caused by hyperparasitism in the solitary parasitoid Lysiphlebus hirticornis (Hymenoptera: Braconidae: Aphidiinae)Manfred MACKAUER, Wolfgang VÖLKLEur. J. Entomol. 102 (3): 475-481, 2005 | DOI: 10.14411/eje.2005.068 We examined the influence of offspring mortality caused by hyperparasitism on the secondary sex ratio of Lysiphlebus hirticornis Mackauer, a solitary endoparasitoid of the aphid Metopeurum fuscoviride Stroyan, in the field. Females of L. hirticornis produce pseudo-gregarious broods, which may comprise more than 200 offspring. Hyperparasitoids [mainly Syrphophagus aphidivorus (Mayr)] attacked and killed up to 60% of the primary parasitoids inside mummified aphids, especially late in the season. Hyperparasitized broods were larger than hyperparasitoid-free broods, which suggests that the risk of hyperparasitism increased with mummy density. We tested the hypothesis that mortality caused by hyperparasitism is greater for female than male offspring of L. hirticornis. If mummy quality scales with mummy size, hyperparasitoids should choose the relatively larger over the relatively smaller mummies. In the absence of hyperparasitism, broods of L. hirticornis included approximately two daughters for each son; the sex ratio did not vary with brood size. In hyperparasitized broods, the sex ratio was nearly even. This result indicates that relatively more female offspring (developing in the larger mummies) than male offspring (developing in the smaller mummies) were killed by hyperparasitoids. We propose that sex-differential offspring mortality in L. hirticornis is the result of differences in optimal host choice between the primary parasitoid and the hyperparasitoids. |
BOOK REVIEW: Fellowes M.D.E., Holloway G.J & Rolff J. (eds) 2005: Insect Evolutionary Ecology.A. HONĚKEur. J. Entomol. 103 (4): 764, 2006 | DOI: 10.14411/eje.2006.102 CABI Publishing, Cambridge MA, USA, 448 pp. ISBN 0-85199-812-7. Price GBP 85.00, USD 160.00. |
BOOK REVIEW: Koster J.C. & Sinev S.Yu.: MOMPHIDAE, BATRACHEDRIDAE, STATHMOPODIDAE, AGONOXENIDAE, COSMOPTERIGIDAE, CHRYSOPELEIIDAE. In Huemer P., Karsholt O. & Lyneborg L. (eds): MICROLEPIDOPTERA OF EUROPE 5.J. JARO©Eur. J. Entomol. 103 (3): 698, 2006 | DOI: 10.14411/eje.2006.092 Apollo Books, Stenstrup, 2003, 387 pp. ISBN 87-88757-66-8. Price DKK 720.00. |
Oldest records of Bombyliidae: Phthiriinae and Mythicomyiidae: Glabellulinae from the Lowermost Eocene amber of France (Diptera: Bombylioidea)André NELEur. J. Entomol. 103 (1): 109-114, 2006 | DOI: 10.14411/eje.2006.016
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Larval morphology of three species of Hygrobiidae (Coleoptera: Adephaga: Dytiscoidea) with phylogenetic considerationsYves ALARIE, Rolf G. BEUTEL, Chris H.S. WATTSEur. J. Entomol. 101 (2): 293-311, 2004 A provisional larval groundplan of the family Hygrobiidae is provided through descriptions of internal and external features of three of six extant species, Hygrobia hermanni (Fabricius, 1775), H. wattsi Hendrich 2001 and H. australasiae (Clark, 1862) and phylogenetic interpretations. Hygrobiidae larvae are morphologically differing dramatically from all other known Adephaga by 20 autapomorphies. Structures involved with feeding, i.e., mouthparts, prepharynx and foregut are highly modified as a result of a specialisation on small tubificid worms and chironomid larvae. A placement of Hygrobiidae within Dytiscoidea is well supported by the reduced condition of the terminal abdominal segments, and the presence of 10 ancestral setae on femur and a clade comprising Hygrobiidae, Amphizoidae, and Dytiscidae by the presence of thin and elongate caudal tentorial arms, a very strong musculus verticopharyngalis and a longitudinally divided adductor tendon of the mandible. A highly modified foregut, reduced terminal spiracles VIII and the presence of tubular gills are features which distinguish hygrobiid larvae from those of other groups of Dytiscoidea (i.e, Amphizoidae, Noteridae, Dytiscidae). A sister-group relationship between Hygrobiidae and Dytiscidae is indicated by a distinctly shortened and transverse prepharynx and a cerebrum and suboesophaeal ganglion shifted to the anterior third of the head. Larvae of the Australian species H. wattsi and H. australasiae share the presence of a bluntly rounded mandible and an apical position of the primary pore MNd in instar I as potential synapomorphies. |
Effect of photoperiod on the duration of summer and winter diapause in the cabbage butterfly, Pieris melete (Lepidoptera: Pieridae)Hai-Jun XIAO, Dong YANG, Fang-Sen XUEEur. J. Entomol. 103 (3): 537-540, 2006 | DOI: 10.14411/eje.2006.071 Effect of photoperiod on the duration of summer and winter diapause was investigated in the cabbage butterfly, Pieris melete. By keeping naturally induced aestivating and hibernating pupae under various photoperiods, it was shown that diapause duration of aestivating pupae was significantly longer at long than at short daylengths, whereas diapause duration of hibernating pupae was significantly shorter at long than at short daylengths, suggesting both aestivating and hibernating pupae require opposite photoperiodic signals to promote diapause development. By transferring diapausing pupae, induced under various photoperiods, to 20°C with a naturally changing summer daylength, the diapause induced by short daylengths was easier to terminate than diapause induced by long daylengths. When naturally induced aestivating and hibernating pupae were kept under natural conditions, aestivating pupae had a long diapause (mean 155 days) and wide range of emergence (90 days), whereas hibernating pupae had a short diapause (mean 105 days) and a relatively synchronized emergence (lasted 30 days). Finally, the ecological significance of photoperiodic regulation of diapause duration is discussed. |
Review of the genus Vibronychiurus (Collembola: Onychiuridae), with a description of two new speciesRomuald J. POMORSKIEur. J. Entomol. 103 (3): 673-677, 2006 | DOI: 10.14411/eje.2006.087 A new diagnosis of Vibronychiurus Pomorski, 1998 is given. V. archivari (Christiansen, 1956) comb. n. and V. hermonicus (Gruia, Poliakov & Broza, 2000) stat. & comb. n. are redescribed on the basis of the types and new specimens. Two new species are described: V. aestimabilis sp. n. from Khakasiya (Russia) and V. caucasicus sp. n. from Caucasus (Russia). A key to the species Vibronychiurus is provided. |
Foraging in a complex environment - semiochemicals support searching behaviour of the seven spot ladybirdJan PETTERSSON, Velemir NINKOVIC, Robert GLINWOOD, Michael A. BIRKETT, John A. PICKETTEur. J. Entomol. 102 (3): 365-370, 2005 | DOI: 10.14411/eje.2005.053 Knowledge of semiochemically-mediated behavioural mechanisms of the seven-spot ladybird, Coccinella septempunctata L., is limited but sufficient to encourage further studies in the behavioural ecology of this well known insect. Recent findings on semiochemicals are discussed in relation to the main traits in the ecology of C. septempunctata. A putative autumn aggregation pheromone, and effects of allelobiotic plant interactions on habitat preferences of adults are reported. Mechanisms for interaction between an aphid alarm pheromone and plant substances are described, and the kairomonal functions of volatiles from C. septempunctata on the parasitoid Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae) are discussed. Considering the polyphagous diet of C. septempunctata, investigations on the importance of associative learning of chemical cues in foraging behaviour, and further studies on interactions with other third trophic level organisms will provide interesting lines of research. |
Maternal age and endogenous variation in maternal influence on photoperiodic response in the progeny diapause in Trichogramma embryophagum (Hymenoptera: Trichogrammatidae)Sergey Ya. REZNIK, Tatyana S. KATS, Taisiya Ya. UMAROVA, Nataliya D. VOINOVICHEur. J. Entomol. 99 (2): 175-179, 2002 | DOI: 10.14411/eje.2002.025 A laboratory study was carried out on photoperiodic control of prepupal diapause in the egg parasitoid Trichogramma embryophagum (Hartig). All experiments were conducted with an isofemale parthenogenetic strain. The maternal generation was reared at 20°C and photoperiods of L:D = 3:21, 6:18, 9:15, 12:12, 15:9, 18:6, 21:3 or 24:0. The tendency to diapause in the progeny was estimated by rearing the daughter generation at 15°C in the dark. Experiments revealed a long-day type response based on maternal influence on the progeny prepupal diapause. However, significant endogenous fluctuations in the pattern of the photoperiodic curve were revealed in successive laboratory generations reared under constant conditions. The left threshold day-length was very variable, while the right threshold kept relative constancy. Experiments with individual females sequentially offered new host eggs demonstrated that the probability of the progeny entering diapause depends significantly on maternal age. At 20°C and 18L : 6D, the percentage of diapause was maximal (ca 15%) in the progeny eclosed from the eggs laid during 1st - 2nd days of maternal life. Then the proportion of diapausing progeny decreased to 0-5% at days 9-11 of female life and later slightly increased in 15-17 days old females. Thus, endogenous factors play an important role in maternal influence on progeny diapause, particularly in environments close to threshold temperature and photoperiod. |
Book Review: The Insect Ovary. Ultrastructure, Previtellogenic Growth and Evolution.STYS P.Eur. J. Entomol. 95 (1): 34, 1998 Büning J.: The Insect Ovary. Ultrastructure, Previtellogenic Growth and Evolution. Chapman & Hall, London, etc., 1994, x + 400 pp., illustr. |
Pepila Weise: Taxonomic identity of the genus and revision of the megalopoides species-group, and description of two new species from Australia (Coleoptera: Chrysomelidae: Alticinae)Maurizio BIONDI, Paola D'ALESSANDROEur. J. Entomol. 100 (3): 371-379, 2003 | DOI: 10.14411/eje.2003.058 In this paper some taxonomic observations on the Australian flea beetle genus Pepila Weise, 1923 are reported. The following species are transferred to the genus Pepila and lectotypes for them designated: Chaetocnema carinata Baly, 1877; Plectroscelis crassipennis Blackburn, 1896; Chaetocnema fuscomaculata Baly, 1877; Plectroscelis hypocrita Blackburn, 1896; Chaetocnema laticeps Baly, 1877; Plectroscelis meyricki Blackburn, 1896; Dibolia ochracea Waterhouse, 1838; Plectroscelis pallidior Blackburn, 1896; Dibolia pygmaea Waterhouse, 1838; Plectroscelis quadraticollis Blackburn, 1896; Chaetocnema submetallescens Baly, 1877; Plectroscelis tumbyensis Blackburn, 1896; Chaetocnema waterhousei Baly, 1877. The synonymy of Chaetocnema submetallescens Baly, 1877 with Plectroscelis longior Blackburn, 1896 is proposed. In addition, the megalopoides species-group, including P. megalopoides Weise, 1923, P. uptoni n.sp., and P. longifallica n.sp., is analyzed. |
TIMELESS: A link between fly's circadian and photoperiodic clocks?Jaroslav PAVELKA, Kimio SHIMADA, Vladimir KOSTALEur. J. Entomol. 100 (2): 255-265, 2003 | DOI: 10.14411/eje.2003.041 Potential involvement of circadian clock genes in so far unknown mechanism of photoperiodic time measurement is an important question of insect life-cycle regulation science. Here we report about the cloning of full-length cDNA of the structural homologue of the Drosophila's timeless gene in Chymomyza costata. Its expression was compared in two strains: a wild-type strain, responding to short days by entering larval diapause and a npd-mutant strain, showing no photoperiodic response. The timeless mRNA transcripts were not detectable by Northern blot analysis in the fly heads of npd-mutants, while they were detectable and showed typical daily oscillations in the wild-type strain. After disrupting the normal process of timeless transcription in the wild-type strain by injection of timeless double-strandRNA into early embryos of wild-type (RNAi method: Kennerdell & Carthew 1998, 2000), a certain proportion of the individuals adopted a npd-mutant phenotype, showing no-diapause in response to short-daylength. Cloning of genomic DNA fragments revealed that npd-mutants carry a different allele, timelessnpd, with a 13-bp insertion in an intron positioned within the 5'-leader sequence. Genetic linkage analysis showed that the 13-bp insertion (a marker for timelessnpd) and the absence of response to short days (a marker for npd-phenotype) are strictly co-inherited in the F2 progeny of the reciprocal crosses between wild-type and npd-mutant flies. Such results indicated that the locus npd could code for the timeless gene in C. costata and its product might thus represent a molecular link between circadian and photoperiodic clock systems in this fly. |
Acceptance and suitability of Acyrthosiphon pisum and Sitobion avenae as hosts of the aphid parasitoid Aphidius ervi (Hymenoptera: Braconidae)Pauline DAZA-BUSTAMANTE, Eduardo FUENTES-CONTRERAS, Hermann M. NIEMEYEREur. J. Entomol. 100 (1): 49-53, 2003 | DOI: 10.14411/eje.2003.010 Aphidius ervi Haliday is a parasitoid of natural populations of both Acyrthosiphon pisum (Harris) on alfalfa and Sitobion avenae (Fabricius) on wheat in Chile. In this study the performance of the aphid parasitoid on both host species was evaluated. Regardless of origin, both females and males of A. ervi were significantly smaller when reared on S. avenae than on A. pisum. Males and females of A. ervi reared on S. avenae on wheat also took significantly longer to develop than when reared on A. pisum. There was no significant difference in the sex ratio of the parasitoid when reared on these two host aphids. Survival of parasitoids from the A. pisum - alfalfa system was significantly lower when reared on S. avenae relative to those reared on A. pisum, but no significant difference in survival on both hosts was detected in parasitoids from the S. avenae - wheat system. Behaviour of parasitoid females during oviposition, such as frequency of encounters, number of attacks and stabbings of host aphids, were significantly higher in the A. pisum - A. ervi interaction than in the S. avenae - A. ervi interaction, regardless of the origin of the parasitoid. Aphid defensive reactions such as kicking or production of cornicle secretion, were significantly higher in the A. pisum - A. ervi than the S. avenae - A. ervi interaction. The results are discussed in relation to the effect of host quality and host aphid body size on parasitoid development. |
Influence of prey host plant on a generalist aphidophagous predator: Episyrphus balteatus (Diptera: Syrphidae)Nicolas VANHAELEN, Charles GASPAR, Frédéric FRANCISEur. J. Entomol. 99 (4): 561-564, 2002 | DOI: 10.14411/eje.2002.074 Secondary plant metabolites (allelochemicals) play a major role in plant-insect interactions. Glucosinolates (GLS) and their degradation products from Brassica species are attractants and feeding stimulants for Brassicaceae specialist insects but are generally repellent and toxic for generalist herbivores. The impact of these compounds on crucifer specialist insects are well known but their effect on generalist predators is still not well documented. The influence of the prey's host plant on both development and reproduction of an aphidophagous beneficial, the hoverfly Episyrphus balteatus, was determined using the cabbage aphid, Brevicoryne brassicae (a specialist) and the peach aphid Myzus persicae (a generalist) reared on two crucifer plants, Brassica napus and Sinapis alba containing low and high GLS levels respectively. |
Raphogla rubra gen. n., sp. n., the oldest representative of the clade of modern Ensifera (Orthoptera: Tettigoniidea, Gryllidea)Olivier BETHOUX, André NEL, Jean LAPEYRIE, Georges GAND, Jean GALTIEREur. J. Entomol. 99 (1): 111-116, 2002 | DOI: 10.14411/eje.2002.019 Raphogla rubra gen. n., sp. n., oldest representative of the (Tettigoniidea & Gryllidea) is described from the Upper Permian of the Lodève basin (France). Its phylogenetic relationships within the Ensifera are discussed. The new taxon occupies a very basal position, probably as sister group of the whole group (Tettigoniidea & Gryllidea). |
Book Review: The Bionomics of Grasshoppers, Katydids and Their Kin.STYS P.Eur. J. Entomol. 95 (2): 319-320, 1998 Gangwere S.K., Muralirangan M.C. & Muralirangan M. (eds): The Bionomics of Grasshoppers, Katydids and Their Kin. CAB International, Wallingford (UK) and New York, 1997, xiii + 529 pp. |
Thermoperiodic effects on diapause of Sesamia nonagrioides (Lepidoptera: Noctuidae)Argyro A. FANTINOU, Costas S. CHATZOGLOU, Elena A. KAGKOUEur. J. Entomol. 99 (4): 421-425, 2002 | DOI: 10.14411/eje.2002.052 The role of the thermophotoperiod on larval diapause induction and development of Sesamia nonagrioides was investigated under laboratory conditions. The incidences of diapause by TC 12 : 12 thermoperiods under DD, in which the thermophase was 30°C and cryophases varied from 10 to 25°C, were compared to the effects of thermophotoperiods with the same configuration. Higher incidences of diapause were recorded when larvae were exposed to thermophotoperiods with cryophases of 15-25°C, than under thermoperiods under constant darkness. In addition, larvae exhibited significantly lower percentages of diapause when exposed to cryophases < 15°C under either thermo- or thermophotoperiodic condition. Diapausing larvae when exposed to photoperiods 16L : 8D h and different temperatures of 25-30°C proceeded to development in 14-16 days. Moreover time needed for the pupation of diapausing larvae after their transfer to 12L : 12D h, was reduced from approximately 49 to 12 days depending on temperatures of exposures (25-30°C). Diapause termination was also compared under 12L : 12D h and constant temperature of 25°C or a thermoperiod of TC 12:12 (30°: 20°). Days needed for pupation at constant temperature or under the mentioned thermoperiodic regime, were approximately the same when the high temperature of the thermoperiod coincided with the scotophase, while with the co-occurrence of the high temperature of the thermoperiod and the photophase significantly additional time was needed for diapause development. Significantly shorter time was also needed for diapause development after exposure of diapausing larvae to continuous light, than to continuous darkness under 25°C. Thermoperiods of different amplitudes with the same mean temperatures proved that the higher temperature of scotophase led to higher rate of diapause development in spite of the relatively low temperature of the photophase tested. It is suggested that thermoperiod could hasten the time needed for diapause development, but it is not the crucial factor for the termination of diapause. |
Spatial and ecological isolation in cicadas: First data from Tibicina (Hemiptera: Cicadoidea) in FranceJérôme SUEUR, Stéphane PUISSANTEur. J. Entomol. 99 (4): 477-484, 2002 | DOI: 10.14411/eje.2002.063 The seven taxa of the cicada genus Tibicina (T.corsica corsica, T. corsica fairmairei, T. garricola, T. haematodes, T. nigronervosa, T. quadrisignata, T. tomentosa) which occur in continental France and Corsica were investigated. Extrinsic factors (geographical barriers) and factors intrinsic to the ecology of species were considered in an effort to understand the biogeography of Tibicina. Three patterns related to intrinsic factors were recognised: (1) pairs of taxa with sympatric distributions but with divergent habitat preferences; (2) pairs of taxa with sympatric distributions and similar habitat but with allochronic occurrence; (3) pairs of taxa with similar ecology but with allopatric distributions. When taxa were separated by their habitat, the height of vegetation appeared to be more important than the floristic composition of the habitat. These factors lead to the partitioning of resources in time and space. All taxa occur in secondary vegetations. Human agro-pastoral activity has probably influenced the dynamics of cicada populations and the maintenance of isolation between them. |
Physiology of cold-acclimation in non-diapausing adults of Pyrrhocoris apterus (Heteroptera)Martin ©LACHTA, Petra BERKOVÁ, Jan VAMBERA, Vladimír KO©«ÁLEur. J. Entomol. 99 (2): 181-187, 2002 | DOI: 10.14411/eje.2002.026 Chill tolerance (time of survival at -5°C) increased in non-diapausing (reproducing) adults of Pyrrhocoris apterus after a gradual, 4-week-long decrease in ambient temperature from 25° to 0°C. The level of chill tolerance attained after cold-acclimation was considerably lower than that in similarly cold-acclimated diapausing adults. Some physiological changes accompanied the cold-acclimation, irrespective of developmental state (diapause vs. reproduction). They were: A decreased oxygen consumption, loss of body water, an increased haemolymph osmolality, an increased proportion of phosphatidylethanolamines vs. a decreased proportion of phosphatidylcholines in membrane phospholipids, and an increased proportion of linoleic vs. a decreased proportion of oleic acid in phosphatidylethanolamines. Such changes could contribute to the limited potential for cold-acclimation found in non-diapausing insects. Other physiological changes appeared to require the induction of diapause prior to cold-acclimation. They were: Down regulation of ice nucleators resulting in a lowering of the individual supercooling point, synthesis and accumulation of specific "winter" polyols, an increased proportion of palmitic acid in membrane phospholipids; and regulation of the concentrations of Na+ and K+ in the haemolymph. The potential contributions of these changes to the cold hardiness of P. apterus are discussed. |