Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

为《Flora of China》提供的伞形科新资料

在为编写《Flora of China》伞形科而进行的修订工作中,提出了11个新组合,即矮小丝瓣芹Acronema minus (M. F. Watson) M. F. Watson & Z. H. Pan, 短柄丝瓣芹A. brevipedicellatum Z. H. Pan & M. F. Watson, 川西当归Angelica sinensis var. wilsonii (H. Wolff) Z. H. Pan & M. F. Watson, 云南细裂芹Harrysmithia franchetii (M. Hiroe) M. L. Sheh, 钝叶独活Heracleum candicans var. obtusifolium (Wall. ex DC.) F. T. Pu & M. F. Watson, 中华天胡荽Hydrocotyle hookeri ssp. chinensis (Dunn ex R. H. Shan & S. L. Liou) M. F. Watson & M. L. Sheh, 普渡天胡荽H. hookeri ssp. handelii (H. Wolff) M. F. Watson & M. L. Sheh, 锐棱岩风Libanotis grubovii (V. M. Vinogradova) M. L. Sheh & M. F. Watson, 美脉藁本Ligusticum likiangense (H. Wolff) F. T. Pu & M. F. Watson和线叶藁本L. nematophyllum (Pimenov & Kljuykov) F. T. Pu & M. F. Watson, 无管藁本L. nullivittatum (K. T. Fu) F. T. Pu & M. F. Watson和二色棱子芹Pleurospermum bicolor (Franch.) C. Norman ex Z. H. Pan & M. F. Watson.; 发现了1个新种,即短柄丝瓣芹。此外,还为Pleurospermum govanianum var. bicolor Franch.指定了后选模式。     

Entomopathogenic Nematode Infectivity Assay: Comparison of Penetration Rate into Different Hosts

Penetration rate (the percentage of the initial infective juvenile inoculum that invades an insect host) was tested as an indicator of entomopathogenic nematode infectivity. Several host-parasite-substrate combinations were evaluated for penetration rate. Four steinernematids, Steinernema carpocapsae, S. glaseri, S. feltiae, S. riobravis and two strains of Heterorhabditis bacteriophora were tested in a contact bioassay against the wax moth, Galleria mellonella, the yellow meal worm, Tenebrio molitor, the beet armyworm, Spodoptera exigua, the black cutworm, Agrotis ipsilon, and the European corn borer, Ostrinia nubilalis. The insect larvae were confined individually in sand and filter paper arenas and exposed to 200 infective juveniles. After incubation, dead insects were dissected in order to count the nematodes penetrated. The data were analyzed for the effects of nematode strain and substrate on penetration rate. The bioassay substrate had a variable effect depending on the insect species. The nematode effect was highly significant for all insects tested. The penetration rate therefore allowed comparisons among nematode strains invading a host. Nematode ranking for infectivity differed according to the insect tested.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

The Role of Parasitoids and Entomopathogenic Fungi in Mortality of Third-instar and Adult Ceroplastes destructor and C. sinensis (Hemiptera: Coccidae: Ceroplastinae) on Citrus in New Zealand

The incidence of parasitism and disease in third-instar and adult Ceroplastes destructor Newstead and C. sinensis Del Guercio (Hemiptera: Coccidae) on citrus in Northland, New Zealand, was measured from 1991-1994. Both species were parasitized by female Euxanthellus philippiae Silvestri (Hymenoptera: Aphelinidae). Female E. philippiae were hyper-parasitized by males of their own species and by Coccidoctonus dubius Girault (Hymenoptera: Encyrtidae). Male E. philippiae were also tertiary parasitoids of C. dubius. E. philippiae was found in third-instar and adult C. sinensis , but was virtually restricted to third-instar C. destructor . Parasitoid phenology varied according to the instar and species of the host. Two fungal pathogens, Verticillium lecanii (Zimmermann) Viegas and Fusarium spp., were identified from both C. destructor and C. sinensis . Disease was a greater mortality factor than parasitism in C. destructor , whereas the opposite applied to those C. sinensis for which the cause of death could be identified. Disease levels were underestimated, particularly in C. destructor. Mortality from parasitism and disease did not act in a density-dependent manner.     

Allozyme relationships among ten species of Rhodniini, showing paraphyly of Rhodnius including Psammolestes

Genetic relationships among 10 species of bugs belonging to the tribe Rhodniini (Hemiptera: Reduviidae), including some important vectors of Chagas disease, were inferred from allozyme analysis of 12 enzyme loci (out of 21 enzyme systems examined), using agarose gel electrophoresis. These species formed two clusters: one comprising Rhodnius brethesi, R. ecuadoriensis, R. pallescens and R. pictipes; the other with Psammolestes tertius, Rhodnius domesticus and the Rhodnius prolixus group comprising R. nasutus, R. neglectus, R. prolixus and R. robustus. The resulting tree was [((R. ecuadoriensis, R. pallescens) R. brethesi) R. pictipes], [R. domesticus (P. tertius [(R. nasutus, R. neglectus) (R. prolixus, R. robustus)])]. Rhodnius nasutus and R. neglectus differed by only one locus, whereas no diagnostic loci were detected between R. prolixus and R. robustus (22 loci were analysed for these four species), despite considerable DNA sequence divergence between species in each of these pairs. Allozymes of the R. prolixus group showed greater similarity with Psammolestes tertius than with other Rhodnius spp., indicating that Rhodnius is paraphyletic and might include Psammolestes.     

Description d'une nouvelle espèce et analyse morpho-fonctionnelle du genre Doryaspis White (Heterostraci) du Dévonien du Spitsberg

Doryaspis groenhorgensis nov. sp. is a new pteraspidiform from the lower devonian of Spitsbergen. The genus Doryaspis is now considered as the most abundant pteraspidiform of the Wood Bay formation, with five described species. Moreover, the pteraspidiform diversity of this formation has been under rated all along the XXth century. A morpho-functional analysis of the Doryaspis generic characters (e.g. flat dorsal shield, ventral pseudorostrum, long cornual plates) allows to consider two possible mode of life. However, none of the pelagic or benthic mode of life is better supported than the other. The same analysis introduce some interpretative hypothesis on histology and moving of the Pteraspidiformes. The Pteraspidiformes diversity of Spitsbergen is important for further Devonian circum-arctic comparisons (e.g. siberian platform).     

Seasonal and Habitat Variability in the Fungal Pathogens, Neozygites cf. floridana and Hirsutella thompsonii, Associated with Cassava Mites in Benin, West Africa

A survey of the pathogenic fungi associated with mites on cassava in Benin, West Africa, revealed both geographical and seasonal variation in the presence of Neozygites cf. floridana (Weiser and Muma) and Hirsutella thompsonii Fisher on Mononychellus tanajoa (Bondar) and Oligonychus gossypii (Zacher). Few dead and infected mites were found during the dry season, regardless of vegetation zone. In three of 30 surveyed sites, N. floridana was found infecting 1% of the dead M. tanajoa and 2% of the dead O. gossypii, while H. thompsonii was observed infecting 20% of the dead M. tanajoa in a single site. The frequency of sites having infected mites during the wet season was 3.5 times greater than that seen during the dry season. N. floridana infected 10% of the dead M. tanajoa and 19% of the dead O. gossypii on young leaves. Mites infected with N. floridana were found either in the coastal Southern Forest Mosaic (SFM) or in the Northern Guinea Savanna vegetation zones. N. floridana was rare in the low mite densities associated with mature leaves. H. thompsonii was found on 19% and 29% of the dead M. tanajoa on young and mature leaves respectively. All M. tanajoa infected with H. thompsonii on young leaves and mature leaves (75%) were found in the SFM. A single M. tanajoa was the only infected mite found in the Southern Guinea Savanna. Relatively few O. gossypii were infected with H. thompsonii. N. floridana and H. thompsonii were found together in three sites, but never on the same host. Phytoseiids were never found infected with either pathogen. In a regression analysis, the number of dead mites was significantly estimated from the total number of mites for both species, regardless of leaf age. The numbers of dead M. tanajoa on mature leaves were also estimated from the proportion infected with H. thompsonii. The numbers of infected mites on young leaves were estimated from their association with the SFM for M. tanajoa infected with H. thompsonii, and from total mites for O. gossypii infected with N. floridana. On mature leaves, infected mite numbers were estimated from the numbers of dead M. tanajoa infected with H. thompsonii. The merit of introducing more virulent or better adapted isolates of N. floridana to control M. tanajoa in Africa is discussed.     

Revision of the Agathidinae (Hymenoptera, Braconidae) of Vietnam, with the description of forty-two new species and three new genera

The species of seventeen genera of Agathidinae (Braconidae) from Vietnam are revised: Agathis Latreille, 1804, Bassus Fabricius, 1804; Biroia Szépligeti, 1900; Braunsia Kriechbaumer, 1894; Camptothlipsis Enderlein, 1920; Coccygidium de Saussure, 1892; Coronagathis gen. n. (type species: Coronagathis cornifera sp. n.); Cremnops Foerster, 1862; Disophrys Foerster, 1862; Earinus Wesmael, 1837; Euagathis Szépligeti, 1900; Gyragathis gen. n. (type species: Gyragathis quyi sp. n.), Gyrochus Enderlein, 1920; Lytopylus Foerster, 1862; Therophilus Wesmael, 1837; Troticus Brullé, 1846, and Zelodia gen. n. (type species: Zelomorpha varipes van Achterberg & Maetô, 1990). Keys to the Vietnamese species are given.Sixty-five species are recognised, of which twelve species are newly recorded for Vietnam: Bassus albifasciatus (Watanabe, 1934), Coccygidium angostura (Bhat & Gupta, 1977), Cremnops atricornis (Smith, 1874), stat. n., Disophrys erythrocephala Cameron, 1900, Gyrochus yunnanensis Wang, 1984, Lytopylus romani (Shestakov, 1940), comb. n., Therophilus festivus (Muesebeck, 1953), comb. n., Therophilus javanus (Bhat & Gupta, 1977), comb. n., Therophilus lienhuachihensis (Chou & Sharkey, 1989), comb. n., Therophilus marshi (Bhat & Gupta, 1977), comb. n., Zelodia absoluta (Chen & Yang, 1998), comb. n. and Zelodia longidorsata (Bhat & Gupta, 1977), comb. n.Forty-two species are new to science: Agathis citrinisoma sp. n., Bassus albobasalis sp. n., Bassus albozonatus sp. n., Biroia soror sp. n., Braunsia bicolorata sp. n., Braunsia devriesi sp. n., Braunsia maculifera sp. n., Braunsia nigrapiculata sp. n., Braunsia pumatica sp. n., Camptothlipsis hanoiensis sp. n., Coronagathis cornifera sp. n., Earinus aurantius sp. n., Earinus brevistigmus sp. n., Euagathis flavosoma sp. n., Disophrys maculifera sp. n., Disophrys quymanhi sp. n., Disophrys rhinoides sp. n., Gyragathis quyi sp. n., Therophilus annuliferus sp. n., Therophilus cattienensis sp. n., Therophilus contrastus sp. n., Therophilus crenulisulcatus sp. n., Therophilus depressiferus sp. n., Therophilus elongator sp. n., Therophilus levisoma sp. n., Therophilus marucae sp. n., Therophilus mellisoma sp. n., Therophilus nigrolineatus sp. n., Therophilus nuichuaensis sp. n., Therophilus parasper sp. n., Therophilus planifrons sp. n., Therophilus punctiscutum sp. n., Therophilus robustus sp. n., Therophilus rugosiferus sp. n., Therophilus scutellatus sp. n., Troticus alloflavus sp. n., Troticus giganteus sp. n., Zelodia albobasalis sp. n., Zelodia anginota sp. n., Zelodia bicoloristigma sp. n., Zelodia brevifemoralis sp. n. and Zelodia flavistigma sp. n.The following new synonyms are proposed: Euagathis nigrithorax Bhat & Gupta, 1977, Euagathis variabilis Enderlein, 1920, Euagathis variabilis var. tibialis Enderlein, 1920, Euagathis variabilis var. melanopleura Enderlein, 1920 and Euagathis variabilis var. sucarandana Enderlein, 1920 with Euagathis abbotti (Ashmead, 1900); Euagathis jinshanensis Chen & Yang, 2006 and Euagathis sharkeyi Chen & Yang, 2006, with Euagathis forticarinata (Cameron, 1899). The genus Amputostypos Sharkey, 2009, is synonymised with Coccygidium de Saussure, 1892, syn. n.The following new combinations are given: Bassus subrasa (Enderlein, 1920), comb. n., Gyragathis angulosa (Bhat & Gupta, 1977), comb. n., Lytopylus romani (Shestakov, 1940), comb. n., Therophilus annulus (Chou & Sharkey, 1989), comb. n., Therophilus asper (Chou & Sharkey, 1989), comb. n., Therophilus cingulipes (Nees, 1812), comb. n., Therophilus daanyuanensis (Chen & Yang, 2006), comb. n., Therophilus fujianicus (Chen & Yang, 2006), comb. n., Therophilus javanus (Bhat & Gupta, 1977), comb. n., Therophilus lanyuensis (Chou & Sharkey, 1989), comb. n., Therophilus luzonicus (Bhat & Gupta, 1977), comb. n., Therophilus muesebecki (Bhat & Gupta, 1977), comb. n., Therophilus rudimentarius (Enderlein, 1920), comb. n., Therophilus similis (Bhat & Gupta, 1977), comb. n., Therophilus sungkangensis (Chou & Sharkey, 1989), comb. n., Therophilus tanycoleosus (Chen & Yang, 2006), comb. n., Therophilus tonghuaensis (Chen & Yang, 2006), comb. n., Therophilus tongmuensis (Chen & Yang, 2006), comb. n., Therophilus transcasperatus (Chen & Yang, 2006), comb. n., Troticus latiabdominalis (Bhat, 1978),comb. n., Zelodia absoluta (Chen & Yang, 1998), comb. n., Zelodia achterbergi (Chen & Yang, 2006), comb. n., Zelodia albopilosella (Cameron, 1908), comb. n., Zelodia chromoptera (Roman, 1913), comb. n., Zelodia nihonensis (Sharkey, 1996), comb. n., Zelodia cordata (Bhat & Gupta, 1977), comb. n., Zelodia diluta (Turner, 1918), comb. n., Zelodia dravida (Bhat & Gupta, 1977), comb. n., Zelodia exornata (Turner, 1918), comb. n., Zelodia longidorsata (Bhat & Gupta, 1977), comb. n., Zelodia longiptera (Yang & Chen, 2006), comb. n., Zelodia maculipes (Cameron, 1911), comb. n., Zelodia nigra (Bhat & Gupta, 1977), comb. n., Zelodia philippinensis (Bhat & Gupta, 1977), comb. n., Zelodia reticulosa (Yang & Chen, 2006), comb. n., Zelodia quadrifossulata (Enderlein, 1920), comb. n., Zelodia ruida (Sharkey, 1996), comb. n., Zelodia similis (Bhat & Gupta, 1977), comb. n., Zelodia penetrans (Smith, 1860), comb. n. and Zelodia varipes (van Achterberg & Maetô, 1990), comb. n.     

Amino acids and sugars in nectar,and their putative evolutionary significance

Individual amino acids and sugars from flower nectar of 32 plant species with different pollination systems were quantified and compared. Data show that there is no correlation between sugar and amino acid concentration. Furthermore there is no correlation between composition and concentration of amino acids and evolutionary advancement, nor any direct relation with pollination systems. However, higher sugar concentrations are often linked with more advanced morphological characters. Nectars from pierced or damaged flowers or nectars contaminated with pollen exhibit modifications and increases in amino acid composition. The presence of proline probably indicates such pollen contamination. Most pollinating animals depend on flower nectar in their energetic requirements, yet innumerable alternative amino acid and protein sources exist. Future research has to consider the relationship between nutritional requirements of pollinating animals and dependence on flower nectars.Dedicated to Prof. Dr.L. van der Pijl, Den Haag, in honour of his 80th birthday.     

Materials for Chinese Phyllanthoideae

The present paper is part of taxonomic study on Chinese Phyllanthoideae. Included in it are two new varieties, Leptopus esquirolii var. villosus and Drypetes hainanensis var. longistipitata, one new combination, Glochidion triandrum var. siamense, and seven new records in China: Drypetes salicifolia, D. hoaensis. Actephila subsessilis, Glochidion khasicum, G. nubigennum, Bridelia spiosa and B. poilanei. In addition, seventeen taxon names are newly reduced: Liodendron formosanum = Drypetes formosana, Liodendron matsumurae = Drypetes matsumurae, D. longipes = D. indica, Antidesma paxii = A. acidum, A. hiiranense, A. filipes and A. pentandrum var. hiiranense = A. japonicum, A. calvescens = A. montanum, A. microphyllum = A. venosum, Breynia stipitata var. formosana and B. jormosana = B. vitis-idaea, Glochidion zeylanicum var. tomentosum = G. hirsutum, G. rubidulum = G. thomsonii, G. acuminatum = G. triandrum, G. fagifolium and Phyllanthus fagifolius = Glochidion sphaerogynum, Bridelia penangiena = B. insulana, B. henryana = B. tomentosa. All the types are kept in SCBl and PE.     

Phylogenetic revision of the Taenogera Kröber genus-group (Diptera: Therevidae), with descriptions of two new genera

The phylogenetic relationships of the Taenogera genus-group, consisting of nine genera, are examined using cladistic methods. Twenty-one species representing nine genera and one outgroup were compared in a cladistic analysis across 99 states in 44 characters. The genus Taenogera Kröber is revised to contain only T. longa (Schiner), T. nitida (Macquart) and T. notatithorax Mann. Two new genera are described and figured: Actenomeros gen. n., with two species, A. corniculaticaudus sp. n. and A. onyx sp. n.; and Taenogerella gen. n., with four species, Ta. elizabethae sp. n., Ta. platina sp. n., Ta. schlingeri sp. n. and Ta . nigrapicalis (Mann) comb. n. Phylogenetic analysis also supports the removal of Nanexila gracilis (Mann) comb. n. from Taenogera .     

Segregate families from the Euphorbiaceae

Segregate families from the Euphorbiaceae. Several families have been segregated from the Euphorbiaceae. Some of these are of long-standing, and are now generally accepted. Others are more recent, and somewhat controversial. Five such have recently been recognized at Kew, and are discussed here, as are two others which have not been so recognized.     

Trypanosoma musculi with Trichinella spiralis or Heligmosomoides polygyrus: concomitant infections in the mouse

Inbred mice infected with Trypanosoma musculi displayed wide variations in peak blood parasitemia. The most susceptible mice were C3H and A strain, while Balb/c, C57B1/6, and the related congenic B10 strains were the most resistant. The effect of an intestinal infection with either Trichinella spiralis or Heligmosomoides polygyrus on proliferation of T. musculi was investigated. T. spiralis infections given at the same time or up to 45 days before a T. musculi infection always caused an increase in blood parasitemia in C3H mice. Maximum increases were observed when T. spiralis infections preceded T. musculi by 5-10 days. In all mouse strains examined, dual infections increased maximum parasitemia by two- to four-fold, regardless of the degree of resistance of that mouse strain to either T. musculi or T. spiralis. This suggested that the immunological "cost" of a T. spiralis infection was the same for strains that were strong or weak responders to a primary infection with T. spiralis. In contrast, infection with H. polygyrus did not promote T. musculi parasitemia over the level of a single infection. The increase in blood parasitemia in T. spiralis-infected mice was largely due to the intestinal adult worm, but migratory larvae and mature muscle larvae also stimulated increased parasitemias. The increase in parasitemia was proportionate to the dose of T. spiralis, and the sex of the host did not affect the blood trypanosome level.     

Comparison of Bioassays to Measure Virulence of Different Entomopathogenic Nematodes

Five bioassays were compared for their usefulness to determine the virulence of four nematode strains. The objective of this study was to develop standard assays for particular nematode species. In all assays, the nematodes Steinernema feltiae (strain UK), S. riobravis, S. scapterisci Argentina and Heterorhabditis bacteriophora HP88 were exposed to Galleria mellonella larvae. All bioassays except the sand column assay were conducted in multi-well plastic dishes. In the penetration rate assay, the number of individual nematodes invading the insect was determined after a 48-h exposure to 200 infective juveniles (IJs). In the one-on-one assay, each larva was exposed to an individual nematode for 72 h before insect mortality was recorded. In the exposure time assay, insect mortality was recorded after exposure to 200 IJs for variable time periods. The dose-response assay involved exposing larvae to different nematode concentrations over the range 1-200 IJs/insect and recording mortality every 24 h for a 96-h period. In the sand columns assay, insects were placed in the bottom of a plastic cylinder filled with sand. Nematodes were applied on top of the sand and insect mortality was determined after IJs had migrated through the cylinder. The highest mortality level in the sand column assay was obtained with IJs of S. feltiae followed by H. bacteriophora; treatments with S. riobravis and S. scapterisci produced low levels of insect mortality. In the other four assays, S riobravis was the most virulent, followed by S. feltiae, H. bacteriophora and S. scapterisci. In the exposure time assay, rapid mortality was achieved when the insects were exposed to S. feltiae and S. riobravis. For these nematode species, a gradual increase in the number of individuals which penetrated into cadavers was recorded. Conversely, the number of nematodes in the cadavers of insects infected by H. bacteriophora and S. scapterisci remained low during the entire exposure period. In this assay, exposing the insects to these nematodes resulted in a gradual increase in mortality. In the dose-response assay, complete separation among nematode species was obtained only after 48 h of incubation at a concentration of 15 IJs/insect. LD and LD values were calculated from 50 90 dose-response assay data. However, these values did not indicate differences among the different nematode species. The present study demonstrated the variation in entomopathogenic nematode performance in different bioassays and supports the notion that one common bioassay cannot be used as a universal measure of virulence for all species and strains because nematodes differ in their behavior. Furthermore, particular assays should be used for different purposes. To select a specific population for use against a particular insect, assays that are more laborious but which simulate natural environmental conditions (e.g. the sand column assay) or invasion by the nematode (e.g. the penetration rate assay) should be considered. In cases where commercial production batches of the same nematode strains are compared, simple and fast assays are needed (e.g. the one-on-one and exposure time assays). Further studies are needed to determine the relationships between data obtained in each assay and nematode efficacy in the field.     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Trypanosoma musculi and Trichinella spirails: Concomitant infections and selection for resistance genotypes in mice

Trypanosoma musculi infections were given to mice of different strains before, at the same time, and after an infection with 400 Trichinella spiralis. Examined parameters of the host response to T. spiralis were worm rejection, antifecundity responses, development of immunological memory, and muscle larvae burden. After dual infection, each mouse strain showed characteristic effects on resistance to T. spiralis. This was due to a dynamic interaction between the genes controlling rejection of T. spiralis and those influencing T. musculi growth. C3H mice develop high trypanosome parasitemias. This impairs worm expulsion and the development of memory to T. spiralis when Trypanosoma infections take place on the same day or 7 days before. The C57B1/6 mouse develops low parasitemias and T. musculi infections on the same day, or 7 days before T. spiralis, delaying worm rejection only slightly despite the overall weak capacity of B6 mice to expel worms. NFR-strain mice are strong responders to T. spiralis and also develop low parasitemias. Trypanosome infections on the same day, or after T. spiralis, produce a delay in worm rejection; the former is comparable to C3H mice. However, NFR mice alone showed enhanced rejection of worm when T. musculi infections preceded T. spiralis by 7 days. An unusual feature of C3H mice was that T. musculi infections 7 days before T. spiralis increased antifecundity responses at the same time that worm expulsion was inhibited. Trypanosome infections can therefore modulate distinct antihelminth immune responses in different directions simultaneously. The different outcomes of dual infections compared with single infections provides another selective mechanism by which genetic polymorphisms can be established and maintained in the vertebrate host.     

Impact of Entomopathogenic Nematodes on Different Soil-dwelling Stages of Western Flower Thrips, Frankliniella occidentalis (Thysanoptera: Thripidae), in the Laboratory and Under Semi-field Conditions

The impact of entomopathogenic nematodes (EPN) on mortality of soil-dwelling stages of western flower thrips (WFT), Frankliniella occidentalis (Thysanoptera: Thripidae) with different insect stage combinations was studied in the laboratory and under semi-field conditions. In laboratory experiments, the efficacy of Steinernema feltiae strain Sylt (Rhabditida: Steinernematidae) at a concentration of 400 infective juveniles (IJs) cm -2 was tested against different proportions of soil-dwelling stages of WFT, i.e. late second instar larvae (L2), prepupae and pupae. Soil was used as the testing medium. S. feltiae significantly affected the mortality of all soil-dwelling life stages of WFT at all tested insect stage combinations. The proportion of late L2 in the population negatively correlated to EPN-induced mortality. WFT prepupa and pupa were similarly susceptible to S. feltiae and their proportion in the population did not affect the EPN-induced mortality under laboratory conditions. The highest mortality (80%) was recorded when the population consisted only of prepupae and/or pupae. In the semi-field study, the impact of S. feltiae , S. carpocapsae strain DD136 and Heterorhabditis bacteriophora strain HK3 (Rhabditida: Heterorhabditidae) ( H. bacteriophora ) at concentrations of 400 and 1000 IJs cm -2 was evaluated against WFT reared on green beans, Phaseolus vulgaris L., as host plant in pot experiments in a controlled climate chamber. All tested EPN strains at both dose rates significantly reduced the WFT populations. Up to 70% reduction of the WFT population was obtained at the higher EPN concentration.