Reviews of publications

Book reviewed in this article: Die Milben des Süsswassers (Hydrachnellae und Halacaridae [part.], Acari) Teil 1: Bibliographie, Teil 2: Katalog, by Kurt O. Viets. A Primate Radiation: Evolutionary Biology of the African Guenons, edited by Annie Gautier-Hion, F. Bourlière, J.-P. Gautier and J. Kingdon. Neurobiology of the Cardiorespiratory System, edited by E. W. Taylor. The Dragonflies of Europe, by R. R. Askew. Studying Fossil Horses, by V. Eisenmann, M. T. Alberdi, C. de Giuli & U. Staesche. Collected papers after the ‘New York International Hipparion Conference. 1981’ Volume I: Methodology, edited by M. Woodburne & P. Sondaar. E. J. Brill. The Hymenoptera, edited by Ian Gauld & Barry Bolton. A Study of Blackbirds, by David Snow Temperature Biology of Animals, by Andrew R. Cossins and Ken Bowler. Honey Identification, by Rex Sawyer. Megaherbivores: The Influence of Very Large Body Size on Ecology, by R. N. Owen-Smith.     

Quantitative Structure-Activity Relationships for the Pre-Steady State of <Emphasis Type="Italic">Pseudomonas Species</Emphasis> Lipase Inhibitions by <Emphasis Type="Italic">p</Emphasis>-Nirophenyl-<Emphasis Type="Italic">N</Emphasis>-Substituted Carbamates

The pre-steady states of Pseudomonas species lipase inhibitions by p-nitrophenyl-N-substituted carbamates (1–6) are composed of two steps: (1) formation of the non-covalent enzyme–inhibitor complex (E:I) from the inhibitor and the enzyme and (2) formation of the tetrahedral enzyme–inhibitor adduct (E–I) from the E:I complex. From a stopped-flow apparatus, the dissociation constant for the E:I complex, K_S, and the rate constant for formation of the tetrahedral E–I adduct from the E:I complex, k₂ are obtained from the non-linear least-squares of curve fittings of first-order rate constant (k_obs) versus inhibition concentration ([I]) plot against k_obs=k₂+k₂[I]/(K_S+[I]). Values of pK_S, and log k₂ are linearly correlated with the σ^* values with the ρ^* values of −2.0 and 0.36, respectively. Therefore, the E:I complexes are more positive charges than the inhibitors due to the ρ^* value of −2.0. The tetrahedral E–I adducts on the other hand are more negative charges than the E:I complexes due to the ρ^* value of 0.36. Formation of the E:I complex from the inhibitor and the enzyme are further divided into two steps: (1) the pre-equilibrium protonation of the inhibitor and (2) formation of the E:I complex from the protonated inhibitor and the enzyme.     

Polymorphisms of the CYP1A1 and CYP2E1 genes in head and neck squamous cell carcinoma risk

Polymorphisms in genes that encode P450 cytochrome enzymes may increase carcinogen activation or decrease their inactivation and consequently, promote the development of cancer. The aims of this study were to identify the MspI-CYP1A1, PstI-CYP2E1 and DraI-CYP2E1 polymorphisms in patients with head and neck cancer and to compare with individuals without cancer; to evaluate the association of these polymorphisms with risk factors and clinical histopathological parameters. In the study group, 313 patients were evaluated for CYP1A1, 217 for CYP2E1 (PstI) and 211 for CYP2E1 (DraI) and in the control group 417, 334 and 374 individuals, respectively. Molecular analysis was performed by PCR–RFLP technique, and chi-square and multiple logistic regression tests were used for statistical analysis. The result of analysis regarding individuals evaluated for CYP1A1 (MspI) showed that age (OR: 8.15; 95% CI 5.57–11.92) and smoking (OR: 5.37; 95% CI 3.52–8.21) were predictors for the disease; for the CYP2E1 (PstI and DraI), there were associations with age (PstI-OR: 9.10; 95% CI 5.86–14.14/DraI-OR: 8.07; 95% CI 5.12–12.72), smoking (PstI-OR: 4.10; 95% CI 2.44–6.89/DraI-OR: 5.73; 95% CI 3.34–9.82), alcohol (PstI-OR: 1.93; 95% CI 1.18–3.16/DraI-OR: 1.69; 95% CI 1.02–2.81), respectively, with disease development. CYP2E1 (PstI) was less frequent in patient group (OR: 0.48; 95% CI 0.23–0.98). Regarding clinical histopathological parameters, CYP1A1 polymorphism was less frequent in the larynx primary anatomic site (OR = 0.45; 95% CI = 0.28–0.73; P = 0.014). In conclusion, we confirm that age, smoking and alcohol consumption are risk factors for this disease and the polymorphisms investigated have no association with the development of head and neck cancer.     

Reviews of publications

Book reviewed in this article: Reproduction of Marine Invertebrates. Vol. VI. Echinoderms and Lophophorates, edited by A. C. Giese, J. S. Pearse and V. B. Pearse. Pacific Grove, California, U.S.A. The Butterflies of Kenya and their Natural History, by T. B. Larsen. The Land and Freshwater Molluscs of Suffolk, by I. J. Killeen. Ipswich, U.K. Flycatcher. Memoirs of an Amateur Entomologist by K. A. Spencer. Ecosystems of the World 24. Intertidal and Littoral Ecosystems, edited by A. C. Mathieson and P. H. Nienhuis. Revision of the Northeast Atlantic and Mediterranean Stylasteridae (Cnidaria: Hydrozoa), by Helmut Zibrowius and Stephen D. Cairns. Paris: Mémoires du Musée Nationale d'Histoire Naturellee, 1992. Animals and Disease. An Introduction to the History of Comparative Medicine, by L. Wilkinson. The Inevitable Bond. Examining Scientist-Animal Interactions, edited by H. Davis and D. Balfour. Martin Lister's English Spiders (1678), edited by J. Parker and B. Harley (translated by M. Davies and B. Harley)). The Ecology of Fishes on Coral Reefs, edited by P. F. Sale. San Diego, USA: The Lepidoptera: Form, Function and Diversity, by M. J. Scoble. Bats. A Community Perspective, by J. S. Findley. The Insects of Australia. A textbook for students and research workers, Commonwealth Scientific and Industrial Research Organisation. Second Edition. Botanical monkeys, by E. J. H. Corner. The Biology of Millipedes, by S. P. Hopkin and H. J. Read. Mammals in the Palaearctic Desert: Status and Trends in the Sahara-Gobian Region, edited by J. A. McNeely and V. M. Neronov. Coelenterate Biology: Recent Research on Cnidaria and Ctenophora, edited by R. B. Williams, P. F. S. Cornelius, R. G. Hughes and E. A. Robson. Dordrecht, The Netherlands: Kluwer Academic Publishers, 1991. Animal Behaviour, 4th ed., by A. Manning and M. S. Dawkins. Weevils, Naturalists' Handbook 16, by M. G. Morris. Insects on Cabbage and Oilseed Rape. Naturalists' Handbooks 18, by W. D. J. Kirk.     

The enemy of my enemy is still my enemy: competitors add to predator load of a tree‐killing bark beetle

1 The mountain pine beetle Dendroctonus ponderosae is a major tree‐killing bark beetle in North America. We evaluated how the subsequent arrival of a competing bark beetle Ips pini influences the arrival of predators and their impact on both species. 2 The predators Temnochila chlorodia and Enoclerus sphegeus were strongly attracted to pheromones of D. ponderosae. By contrast, Enoclerus lecontei was mostly attracted to I. pini pheromones. The host compound myrcene synergized attraction of both D. ponderosae and E. sphegeus to the pheromone of D. ponderosae. However, it inhibited attraction of both I. pini and E. lecontei to I. pini’s pheromone. 3 Dendroctonus ponderosae were more attracted to trees than logs treated with its pheromones, whereas I. pini were more attracted to logs than trees treated with its pheromones. Some 78% of T. chlorodia were captured at hosts baited with D. ponderosae pheromones, whereas 83% of E. lecontei were captured at hosts baited with I. pini pheromones. We characterized the sequence of arrival to live trees baited with pheromones of D. ponderosae as: D. ponderosae, T. chlorodia, E. sphegeus, I. pini, E. lecontei. 4 Various combinations of I. pini and predators were added to logs colonized by D. ponderosae in the above sequence of arrival observed in live trees baited with D. ponderosae aggregation pheromones. Ips pini reduced D. ponderosae adult brood production. However, the combination of I. pini and E. lecontei did not raise D. ponderosae brood production above that observed with only I. pini present. Similarly, the combination of I. pini and T. chlorodia did not reduce D. ponderosae brood production below that observed with I. pini alone. By contrast, the combination of I. pini, T. chlorodia and E. lecontei caused more brood loss to D. ponderosae than I. pini alone. 5 Enoclerus lecontei did not reduce brood production by T. chlorodia, whereas T. chlorodia substantially reduced brood production by E. lecontei. 6 Secondary bark beetles that exploit the resource created by primary tree‐killing species exert negative effects through both competition and increased predator load. Implications to the population dynamics, ecology and evolution of tree‐killing bark beetles are discussed.     

Characterization of uropathogenic E. coli O25b-B2-ST131, O15:K52:H1, and CGA: Neutrophils apoptosis,serum bactericidal assay,biofilm formation,and virulence typing

Pathogenic and drug-resistant strains of Escherichia coli (E. coli) O25b-B2-ST131, O15:H1-D-ST393, and CGA (clonal group A) clonal groups have spread worldwide. This study aimed at determining E. coli epidemic clonal groups, their virulence factors, biofilm formation, neutrophils apoptosis, and antimicrobial resistance pattern of uropathogenic E. coli. A total of 95 CTX-M-1-producing E. coli clinical isolates were enrolled. E. coli O25b-B2-ST131, CGA, and O15:K52:H1 were identified by serotyping and phylogrouping and allele-specific polymerase chain reaction-based assay. Antibiotic susceptibility, biofilm formation, hemolysis, and human serum bactericidal assay were performed. Neutrophil apoptosis was assayed by flow cytometry. Nine E. coli clonal groups including six O25b-B2-ST131 strains, two CGA, and one O15:K52:H1-D-ST393 strains were detected. One O25b-B2-ST131 isolate was a strong biofilm-producer. Three ST131 isolates had type I fimbriae. Furthermore, all the CGA and O15:K52:H1 and three of ST131 isolates harbored the P fimbriae. The virulence genes ompT, fimH, and traT were detected among all the clonal groups. The apoptosis was induced by O25b-B2-ST131, CGA, and O15:K52:H1 E. coli. There was no significant difference regarding apoptosis induction among clonal groups. Furthermore, the presence of the cdt, usp, and vat genes was significantly associated with the apoptosis of neutrophils by O25b-B2-ST131, CGA, and O15:K52:H1-D-ST393 clonal groups.     

GENOME RELATIONS AMONG ELYMUS CANADENSIS,ELYMUS TRITICOIDES,ELYMUS DASYSTACHYS,AND AGROPYRON SMITHII

Hand-emasculated Elymus canadensis pollinated by E. triticoides, E. dasystachys, and Agropyron smithii yielded 15, 21, and 1 viable hybrid seeds from 56, 52, and 52 florets, respectively. The 28-chromosome species—E. canadensis, E. triticoides, and E. dasystachys—behaved meiotically as allotetraploids and consistently formed 14 bivalents at metaphase I. Octoploid A. smithii, 2n = 56, averaged 0.41^I, 27.72^II, and 0.03^IV in 87 metaphase-I cells. Agropyron smithii is apparently an allooctoploid or a segmental autoallooctoploid. Meiosis was similar in the E. canadensis X E. triticoides and E. dasystachys hybrids. Chromosome pairing was very low in both hybrids, about two loosely connected open-ended bivalents per cell, and may not represent genuine homologies. The genomes of E. canadensis are distinctly different from those of E. triticoides and E. dasystachys. The E. canadensis X A. smithii hybrid averaged 13.37^I and 14.31^II in 76 metaphase-I cells. More than half of the bivalents were closed at both ends. Inability to distinguish between auto- and allosyndesis resulted in two interpretations of genome relations. Either A. smithii is an alloploid with two of its four genomes similar to those of E. canadensis, or it is a segmental autoalloploid genomically unrelated to E. canadensis. The first interpretation is favored. Agropyron dasystachyum, or one of its close relatives, and E. triticoides are suggested as possible parents of A. smithii.     

Participation of RNase I in MS2 Phage Growth

Participation of RNase I in the growth of phage on infection with bacteriophage MS2 was studied.

Some strains of uracil-requiring E. coli were isolated, grown in MS broth, and transferred to a minimal medium to exhaust the pool of nucleotides. The phage was then added to the cells grown in uracil-deficient medium. The growth of phage was observed to occur at the burst size of two hundreds in strains of E. coli K12S (F⁺) U^? and C600 (F⁺) U^?, which possessed RNase I, but not in strains, A19 (Hfr) U^? and Q13 (Hfr) U^?, which lacked RNase I.

A marked increase in acid-soluble fraction was observed with E. coli K12S (F⁺) U^? and C600 (F⁺) U^?, whereas the increase was little with E. coli A10 (Hfr) U^? and Q13 (Hfr) U^? Conditions for the growth of phage in uracil-deficient medium were investigated and the effect of antibiotics were also investigated.     

Eucharitid Parasitism of the Neotropical Ant Ectatomma tuberculatum: Parasitoid Co‐occurrence,Seasonal Variation,and Multiparasitism1

Multiparasitism is reported for the first time in Eucharitidae (Hymenoptera: Chalcidoidea). Dilocantha lachaudii, Isomerala coronata, and Kapala sp. were found simultaneously attacking the same population of Ectatomma tuberculatum (Olivier) (Hymenoptera: Formicidae: Ectatomminae) in southern Mexico. Adults of D. lachaudii and I. coronata completed development on the same individual host on three occasions. The genus Kapala is reported for the first time as a parasitoid of E. tuberculatum, and I. coronata is reported in Mexico for the first time.     

Characterization of a 3-dehydroquinase gene from Actinobacillus pleuropneumoniae with homology to the eukaryotic genes qa-2 and QUTE

A gene was cloned from Actinobacillus pleuropneumoniae strain 4074 by complementation of an aroD strain of Escherichia coli. The E. coli gene aroD codes for a 3-dehydroquinase enzyme of type I, active in the aromatic biosynthesis pathway. The A. pleuropneumoniae gene, termed aroQ, displays no base or ami no acid sequence homoiogy to aroD of E. coli. It is instead homologous to the QUTE and qa-2 genes, respectively of Aspergillus niduians and Neurospora crassa. These genes code for 3-dehydroquinase enzymes of type ii, involved in the catabolism of quinic acid. The 1.6 kb fragment, which includes aroQ, carries four overlapping or adjacent open reading frames: a dapD gene; aroQ; one without homology to sequences in GenBank; and one with homology to the C-terminal 40% of chlN of E. coli.     

Meiotic configuration and chromosome number in some Iranian species of Elymus L. and Agropyron Gaertner (Poaceae: Triticeae)

Chromosome numbers and analyses of meiotic metaphase I are reported for the following taxa: Agropyron cristatum subsp. incanum (2n= 42), A. cristatum subsp. pecttnatum (2n=28 – 33), Elymus elongatus subsp. ponticus (2n= 69, 70), E. hispidus var. hispidus (2n= 41 43), var. podperae (2n= 42) and var. villosus (2n= 41, 42), E. libanoticus (2n= 14), E. pertenuis (2n= 28, 28+1B), E. repens (2n= 42), E. transhyrcanus (2n= 40–42), E. hispidus var. villosus x E. cf. repens (2n= 42). Chromosome numbers only are reported for the following taxa: E. gentri (2n= 41, 42), E. nodosus subsp. dorudicus (2n= 28), and E. elongatiformis (2n= 56, 57). The haploid genomic constitution SP is reported for Elymus pertenuis. Variable chromosome numbers (2n= 28–32) were observed in the meiotic metaphase I within single anthers of Agropyron cristatum subsp. pectinatum, and the supernumerary chromosomes in this taxon are assumed to have originated from crosses with hexaploids. Partial elimination of these supernumerary chromosomes probably occurs during archesporial mitotic divisions or at an early stage in the meiotic cycle. A hybrid, morphologically intermediate between E. hispidus and E. repens, was obtained from a seed of E. hispidus collected in the field. The meiotic metaphase I configuration in this E. hispidus hybrid suggests that the pollen parent may itself be a hybrid or hybrid derivative of E. repens x E. hispidus.     

Genomic relationships between species of theElymus semicostatus group andElymus sensu lato (Poaceae)

Meiotic pairing behaviour in 19 interspecificElymus hybrids is reported and discussed. The hybrids were made between four species belonging to theE. semicostatus group of sect.Goulardia, viz.,E. semicostatus, E. abolinii, E. fedtschenkoi, andE. panormitanus (all 2n = 28), andElymus species of seven different sections, viz., sect.Clinelymiopsis:E. caucasicus (2n = 28); sect.Elymus:E. sibiricus (2n = 28); sect.Goulardia:E. caninus (2n = 28),E. trachycaulus (2n = 28), andE. tsukushiensis (2n = 42); sect.Hyalolepis:E. batalinii (2n = 42); sect.Hystrix:E. hystrix (2n = 28); sect.Macrolepis:E. canadensis (2n = 28); and sect.Turczaninovia:E. dahuricus (2n = 42). Chromosomal pairing at meiotic metaphase I indicated that the species of theE. semicostatus group are genomically closer to the tetraploidE. caucasicus and the hexaploid species, regardless of sectional origin, than to the other tetraploid species of sectionGoulardia. Highest meiotic pairing was found in hybrids involvingE. caucasicus, E. tsukushiensis, andE. dahuricus. The presence of pairing regulating genes inE. abolinii is suspected.     

Functional analysis of the minor subunits of S fimbrial adhesion (SfaI) in pathogenic Escherichia coli

S fimbrial adhesins I and II (SfaI and II), produced by extraintestinal Escherichia coli pathogens that cause urinary tract infections (UTI) and newborn meningitis (NBM), respectively, mediate bacterial adherence to sialic acid-containing glycoprotein receptors present on host epithelial cells and extracellular matrix. The S fimbrial adhesin complexes consist of four proteins: SfaI-A, the major subunit protein and the minor subunit proteins SfaI-G, SfaI-S and SfaI-H. Sialic acid-specific binding is mediated by the minor subunit protein SfaI-S. In order to determine whether the minor subunit proteins SfaI-G, -S and -H play a role in the modulation of adherence and the degree of fimbriation, a trans-complementation system was developed. A non-adhesive E. coli K-12 derivative, harbouring the sfaI-A gene but lacking sfaI-G, -S and -H, was transformed with sfaI-G, -S or -H. Only SfaI-S was able to increase the degree of fimbriation and to confer adhesion properties on the recombinant E. coli K-12 strains. Amino acid residues in SfaI-S that are involved in modulation of fimbriation as well as in receptor recognition were localized by random and site-directed mutagenesis. Received: 15 March 1999 / Accepted: 2 November 1999     

Molecular cloning,characterization, and sequencing of the hemolysin gene from Edwardsiella tarda

Hemolysis is a major symptom of diseased eels infected by Edwardsiella tarda. The hemolysin gene of E. tarda strain ET16 was cloned into plasmid pSK and expressed in Escherichia coli. The mol. mass of the functional β-hemolysin was estimated to be approximately 34 kDa by gel filtration and by SDS-PAGE followed by in situ hemolysin activity analysis. The cloned fragment containing the β-hemolysin locus from E. tarda strain ET16 expressed in E. coli was estimated to be 5.3 kb in length; the deduced gene product was identical in mol. mass and properties to the extracellular products of E. tarda strain ET16. The presence of EcoRI and XbaI sites within the β-hemolysin gene of E. tarda was determined from the loss of hemolytic activity in subclones. Analysis of the DNA sequence of a 2,436-bp HaeIII-HindIII fragment that included EcoRI and XbaI sites revealed three ORFs organized as an operon that encoded three predicted polypeptides of 15,874, 7,055, and 34,804 Da. A 34-kDa polypeptide expressing hemolytic activity in cell lysates of the clone DH5α(pETH3E) is very likely the β-hemolysin encoded by the third ORF. The observation that hemolytic activity appeared in the culture medium of E. tarda, but not in that of E. coli strain DH5α(pETH3E) indicates the existence of a mechanism for transporting the hemolysin across the cell envelope in E. tarda that is different from that of E. coli. Received: 7 July 1995 / Accepted: 24 October 1995     

La mouche de l'olive,Dacus oleae gmel. et ses parasites en Corse,en 1959 et 1960

Summary Three known ectoparasites ofD. olea are found in Corsica. These are Chalcidians:Pnigalio mediterraneus, a very active primary parasite,Eurytoma rosae, primary parasite of little importance,Eupelmus urozonus, primary parasite (some-times pseudo-endoparasites) secondary or tertiary, very active and which appear to hinder the action ofP. mediterraneus. Myopites stylata (Dipt. Trypetidae onInula viscosa) does not seem to constitute a host forE. urozonus. The action of the indigenous parasites lessens towards the end of summer and could be relayed by introducing foreign parasites.

---

---

I.N.R.A., Station de Zoologie Centre de Recherches agronomiques du Sud-Est.     

Phylogeography of the East Asian polymitarcyid mayfly genus Ephoron (Ephemeroptera: Polymitarcyidae): a comparative analysis of molecular and ecological characteristics

In East Asia, the mayfly genus Ephoron, a member of Polymitarcyidae, has been classified into three species: Ephoron eophilum, Ephoron limnobium, and Ephoron shigae. Using the nuclear histone 3 and internal transcribed spacer 1 and mitochondrial 16S rRNA and cytochrome c oxidase subunit I genes, we investigated the phylogenetic relationships of these mayflies. Ephoron limnobium formed polyphyletic relationships within the clade of Japanese E. shigae and shared identical sequences with E. shigae, suggesting that E. limnobium is a synonym of E. shigae. Monophyly was supported in E. eophilum, Korean E. shigae, and E. limnobium + Japanese E. shigae. Ephoron eophilum that co‐occurs with the other Ephoron species has several peculiar traits in its adult swarming period and karyotype. This suggests that both pre‐ and post‐zygotic isolation are likely to have promoted speciation of these Ephoron species. The divergence between E. eophilum and E. shigae would have occurred from the late Late Miocene to Early Pliocene according to the Bayesian relaxed clock model calibrated using the mitochondrial substitution rate. The area currently inhabited by E. eophilum emerged above sea level some 0.1 Mya, suggesting that E. eophilum moved into this area from other areas that it occupied prior to this time. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 181–202.     

Action of 1,1-dimethylhydrazine on bacterial cells is determined by hydrogen peroxide

Seven different recombinant bioluminescent strains of Escherichia coli containing, respectively, the promoters katG and soxS (responsive to oxidative damage), recA (DNA damage), fabA (membrane damage), grpE, and rpoE (protein damage) and lac (constitutive expression) fused to the bacterial operon from Photorhabdus luminescens, were used to describe the mechanism of toxicity of 1,1-dimethylhydrazine (1,1-DMH) on bacteria, as well as to determine whether bacteria can sensitively detect the presence of this compound. A clear response to 1,1-DMH was observed only in E. coli carrying the katG’::lux, soxS’::lux, and recA’::lux-containing constructs. Preliminary treatment with catalase of the medium containing 1,1-DMH completely diminished the stress-response of the P_katG, P_recA, and P_soxS promoters. In the strain E. coli (pXen7), which contains a constitutive promoter, the level of cellular toxicity caused by the addition of 1,1-DMH was dramatically reduced in the presence of catalase.It is suggested that the action of 1,1-DMH on bacterial cells is determined by hydrogen peroxide, which is formed in response to reduction of the air oxygen level.     

Erysiphe wadae: a new species of Erysiphe sect. Uncinula on Japanese beech

 A new species of Erysiphe sect. Uncinula is described and illustrated from Japan. Erysiphe wadae sp. nov., found on Japanese beech (Fagus crenata, Fagaceae), is characterized by having two types of appendages, i.e., a long (true) appendage arising from the equatorial zone of the ascomata, and a short appendage arising from the upper part of the ascomata. This characteristic is shared by E. simulans, E. australiana, E. flexuosa, E. liquidambaris, E. prunastri, and E. togashiana. Erysiphe wadae differs from the latter five species in its brown-colored appendage. Erysiphe simulans is most similar to E. wadae, but differs in its loosely uncinate appendage and smaller number of ascospores. Identity of the nucleotide sequences of the rDNA ITS region is 92.3% between the two species. The significance of the two types of appendage in taxonomy and phylogeny of powdery mildews is discussed based on molecular phylogenetic analysis. Received: November 8, 2002 / Accepted: January 29, 2003 Acknowledgments We are grateful to Drs. Yukio Harada and Hideki Naito for help in collecting powdery mildew specimens; Dr. Uwe Braun for providing the specimen of E. flexuosa; and Mr. Tetsuya Hirata and Miss Sanae Matsuda for nucleotide sequences of E. togashiana and E. flexuosa. This work was partially supported by a Grant-in-Aid for Scientific Research (No. 13660047) from Ministry of Education, Culture, Sports, Science and Technology, Japan.     

Host selection by the heteronomous hyperparasitoid Encarsia pergandiella: multiple-choice tests using Bemisia argentifolii as primary host

The ovipositional patterns of the heteronomous hyperparasitoid Encarsia pergandiella Howard (Hymenoptera: Aphelinidae) in the presence of its primary host Bemisia argentifolii Bellows & Perring (Hemiptera: Aleyrodidae), and in the presence or absence of conspecific and heterospecific secondary hosts (Encarsia formosa Gahan andEretmocerus mundus Mercet; Hymenoptera: Aphelinidae) were examined to assess host species preferences. Host preferences by heteronomous hyperparasitoids may affect the relative abundance of co-occurring parasitoid species and may influence host population suppression by the parasitoid community. Four combinations of hosts were tested: (1) B. argentifolii, E. mundus, and E. formosa, (2) B. argentifolii, E. formosa, and E. pergandiella, (3) B. argentifolii, E. mundus, and E. pergandiella, and, (4) B. argentifolii, E. mundus, E. formosa, and E. pergandiella. Arrays of hosts (24) were constructed in Petri dishes using leaf disks, each bearing one host. Thirty arrays of each host combination were exposed to single females for 6 h. All hosts were dissected to determine number of eggs per host. Encarsia pergandiella parasitized E. formosa hosts as frequently as E. mundus hosts. However, E. pergandiella parasitized either of these heterospecific hosts more frequently than conspecific hosts in treatments including two secondary host species. When a third parasitoid species was included in host arrays, E. pergandiella parasitized conspecific hosts as frequently as heterospecific hosts. Developmental stage of the hosts did not significantly influence host species selection by E. pergandiella. Our results indicate that host selection and oviposition by heteronomous hyperparasitoids like E. pergandiella, vary with the composition of hosts available for parasitization, and suggest a preference for heterospecific over conspecific secondary hosts.