Development and reproduction of Myzus persicae and Aphis fabae (Hom., Aphididae) on selected weed species surrounding sugar beet fields

Abstract:   Myzus persicae (Sulzer) and Aphis fabae (Scop.) are two major aphid species colonizing sugar beet. They have a very wide host range adapting to a large number of plant families and species. A series of cage experiments, conducted under 'winter' and 'summer' growth chamber conditions, showed that both species have the potential to use winter and summer weeds that are usually present in the vicinity of and within sugar beet fields as secondary hosts. Among all the weeds tested, Veronica hederifolia L. and Solanum nigrum L. were the most suitable for M. persicae . Although Brassica kaber (DC.) Wheeler was the weed species associated to the highest reproduction rate of this aphid, V. hederifolia showed a higher intrinsic rate of population increase due to the shorter prereproductive period of the aphid. Amsynckia intermedia Fish. and Mey and Amaranthus retroflexus L. were the most suitable weed hosts for A. fabae .     

The effect of aphid prey quality on searching behaviour of Adalia bipunctata and its susceptibility to insecticides

After consumption of one individual of a suitable prey, such as Phorodon humuli (Schrank) (Aphididae), Adalia bipunctata L. (Coleoptera, Coccinellidae) adults changed from extensive to intensive searching behaviour. However, after the consumption of one individual of three other aphid species: Aphis fabae Scop., Aphis craccivora Koch or Aphis spiraephaga Müller, which are unsuitable prey, this coccinellid remained immobile for 12–76 min and did not switch to intensive search after moving off. Adult A. bipunctata fed an unsuitable prey, A. fabae, for 2 weeks were 2–4 times more susceptible to pyrethroid insecticides (permethrin, deltamethrin, fenpropathrin, esfenvalerate, alfa-cypermethrin and bioresmethrin) and insect growth regulators (diflubenzuron, triflumuron, fenoxycarb, flufenoxuron, teflubenzuron) than those fed a suitable prey, P. humuli.The searching behaviour of coccinellids could thus be another criterion for determining the suitability of aphids as prey. The fact that the nutritional quality of aphids can affect the susceptibility of predatory coccinellids to insecticides should be borne in mind in integrated pest management programs.     

A new species of Agrostis (Gramineae) in the A. alpina complex

A new species of Agrostis L. (A. barceloi ) is described from the northern mountains of Mallorca (Balearic Islands). The new taxon belongs to sect. Agtush and is mainly related to A. alpina Scop. and A. schleicheri Jord. & Verl. on morphological grounds. However, A. barceloi differs from A. alpina by its narrowly-lanceolate inflorescence, with panicle branches erect during and after anthesis, non-scabrid leaves, and by smaller lemmas and others. The new species is distinguished from A. schleicheri by the smaller spikelets, lemma, palea, and anthers. In addition, A. barceloi is tetraploid (2n = 28), and differs cytologically from the diploid A. alpina (2n= 14) and the hexaploid A. schleicheri (2n = 56).     

Individual variation in oviposition preference, and its interaction with larval performance in an insect predator

Individual female Episyrphus balteatus (DeGeer) (Diptera: Syrphidae) show different oviposition preferences when presented with two aphid prey species, Aphis sambuci L. and A. fabae (Scop). After larvae were reared on those aphids, some fitness components indicated that individual females were adapted to different host-use strategies, with preference for one aphid prey species entailing a trade-off in poorer performance on another. We interpret the pattern of significant interactions as suggesting that natural selection has responded to the nutritional value of prey. Received: 11 September 1998 / Accepted: 16 November 1998     

Plant species from mesotrophic wetlands cause relatively high methane emissions from peat soil

Plants can influence methane emissions from wetland ecosystems by altering its production, consumption and transport in the soil. The aim of this study was to investigate how eight vascular plant species from mesotrophic to eutrophic wetlands vary in their influence on CH₄ emissions from peat cores, under low and high N supply. Additionally, we measured the production of low-molecular-weight organic acids (LOA) by the same species (also at low and high N supply), because LOA form a substrate for methanogenesis. There were considerable differences among species in their effects upon rates of CH₄ emission. Six of the species (Eriophorum latifolium Hoppe, Potentilla palustris (L.) Scop., Anthoxanthum odoratum (L.) s. str., Carex rostrata Stokes, Carex elata All., Carex acutiformis Ehrh.) increased CH₄ emissions up to five times compared to control peat cores without plants, whereas two species (Phalaris arundinacea L., Phragmites australis (Cav.) Trin. ex Steud.) had no effect. There was a weak negative correlation between plant biomass and CH₄ emission. N addition had no significant general effect upon CH₄ emission. LOA production varied considerably among species, and tended to be highest for species from mesotrophic habitats. LOA production was stimulated by N addition. We conclude that some species from mesotrophic wetlands tend to cause higher CH₄ emissions than species from eutrophic wetlands. This pattern, which contradicts what is often mentioned in literature, may be explained by the higher LOA production rates of species adapted to less productive habitats.     

Nine eriophyoid mite species from Iran (Acari, Eriophyidae)

Nine eriophyoid mites, including two new species and five new records, from Iran are described and illustrated. They are Aceria acroptiloni Shevchenko & Kacalev, 1974, rec. n. on Rhaponticum repens (L.) Hidalgo (Asteraceae); Aceria anthocoptes (Nalepa, 1892), rec. n. on Cirsium arvense (L.) Scop. (Asteraceae); Aceria lactucae (Canestrini, 1893), rec. n. on Lactuca virosa L. (Asteraceae); Aceria pulicarissp. n. on Pulicaria gnaphalodes (Vent.) Boiss. (Asteraceae); Aceria tosichella Keifer, 1969 on Setaria viridis (L.) Beauv. (Poaceae); Eriophyes rotundae Mohanasundaram, 1983 on Cyperus rotundus L. (Cyperaceae); Aculops maroccensis Keifer, 1972, rec. n. on Mentha piperita L. (Lamiaceae); Aculus medicagersp. n. on Medicago sativa L. (Leguminosae); Tetra lycopersici Xue & Hong, 2005, rec. n. on Solanum nigrum L. (Solanaceae).     

Resource partitioning in a guild of aphid species associated with creeping thistle Cirsium arvense

Four aphid species (Aphis fabae cirsiiacanthoidis Scop., Brachycaudus cardui (L.), Capitophorus carduinus Walker and Uroleucon cirsii (L.)) feed on the creeping thistle Cirsium arvense. They utilize different parts of their host plant and at different times. A wide niche is typical of C. carduinus and U. cirsii, whereas A. f. crisiiacanthoidis and B. cardui, show narrower but overlapping niches. Morphological features such as stylet length and body size as well as colony size and density are associated with the choice of feeding site. C. carduinus, the smallest species with the shortest stylets was able to use leaf veins and lamina, while the other species mainly used the stem and peduncles. Within this group, A. f. cirsiiacanthoidis and B. cardui are restricted to the upper part of the stem because of their short stylets, but adult U. cirsii, the species with the longest stylets, can also feed at the base of the stem.

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Räumliche und zeitliche ressourcenaufteilung in der blattlausgilde an der ackerkratzdistel cirsium arvense

Zusammenfassung An der Ackerkratzdistel leben vier Blattlausarten (Aphis fabae cirsiiacanthoidis Scop., Brachycaudus cardui (L.), Capitophorus carduinus Walker und Uroleucon cirsii (L.)), die im Verlauf der Vegetationsperiode verschiedene Strukturen ihrer Wirtspflanze nutzen. Eine breite Nische ist für U. cirsii und C. carduinus typisch, während A. f. cirsiiacanthoidis und B. cardui engere Nischen besitzen, die sich nahezu überlappen. Die Nahrungsplatzwahl wird sowohl durch morphologische Parameter wie Stilettlänge und Körpergewicht als auch durch Koloniegröe und Dispersion innerhalb der Kolonie beeinflut. Die kleinste Art, C. carduinus, die auch das kürzeste Stilett besitzt, ist in der Lage, an Blattadern und auf der Blattspreite zu saugen. Die anderen Arten bevorzugen Stengel, Seitenstengel und Blütenstiele. Innerhalb dieser Gruppe können A. f. cirsiiacanthoidis und C. carduinus wegen ihrer kürzeren Stilette nur am oberen Teil des Stengels saugen, während adulte U. cirsii aufgrund ihrer längeren Stilette auch an der Stengelbasis leben können.

     

The occurrence of unique, long-chain polyprenols in the leaves of Potentilla species

Polyprenols are accumulated in the leaves of Potentilla anserina at concentration up to 0.3% fresh weight. They constitute a mixture of poly-cis fully unsaturated analogues of up to 29 isoprene units long. In this and other species of Potentilla the polyprenol mixture is composed of two families, one grouping the medium chain-length polyprenols (built up of about 20 isoprene units), and the second one, composed mainly of very long prenolgues from 24 to approx. 28 isoprene units. This is a first report on the occurrence of polyprenyl alcohols of this chain length in plant material and the first one on the presence of multiple polyprenol mixture in angiosperms. A useful modification of polyprenols preparation from plant material, based on solid phase extraction with hydrophobic gel Lipidex-5000 is described.     

Bacteria may contribute to distant species recognition in ant–aphid mutualistic relationships

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate‐rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two‐way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses.     

The effects of thirteen species of aphids on some life history parameters of the ladybird Coccinella septempunctata

The prediction of impact ofcoccinellids in an aphid infested crop dependson the food specificity of the predator. Theresponse towards thirteen species of aphids(Sternorrhyncha: Aphididae) was thereforetested in the most abundant aphidophagouscoccinellid Coccinella septempunctata L.(Coleoptera: Coccinellidae). All aphidspecies studied (Eucalipterus tiliae(L.), Tuberculatus annulatus (L.), Euceraphis betulae (L.), Cavariellakonoi Takahashi, Liosomaphis berberidis(Kaltenbach), Acyrthosiphon ignotumMordvilko, Aphis spiraephaga Müller,Aphis fabae Scopoli, Macrosiphoniella artemisiae Boyer de Fonscolombe, Capitophorus hippophaeus(Walk.), Acyrthosiphon pisum (Harris),Aphis craccivora Koch, Sitobionavenae (Fabricius) were suitable foodaccording to the rate of larval development,larval mortality and adult fresh weight.Females of C. septempunctata fed with A. pisum and S. avenae laid twice as manyeggs as those fed with A. fabae and A. craccivora. These data are needed foreffective mass rearing of the studiedcoccinellid species.     

Action of beta radiation on the black bean aphid Aphis fabae Scop. (Aphididae, Homoptera)

A study was made of the effect of direct single exposure to beta-radiation of 0.5, 5, 10, 20, 30, and 50 Gy on development and reproduction of Aphis fabae Scop. (Aphididae, Homoptera). The numbers of bean aphid are prognosticated with regard to the radiation dose applied.     

The songs and calling sites of two European cicadas

Abstract. 1. The male songs of two of the commonest cicadas in southern France are described with oscillograms.
2. Males of Cicada orni L. aggregate during calling whilst those of Lyristes plebeius (Scop.) space themselves out.
3. Both species are widely polyphagous on trees and shrubs, but L. plebeius sings from thinner stems than does C. orni
4. Such behaviour may result in the spatial separation of different species in the same habitat.     

A systematic revision of Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions

IKEDA, H. & OHBA, H., 1993. A systematic revision of Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions . Potentilla lineata and allied species (Rosaceae) in the Himalaya and adjacent regions are revised. Potentilla festiva Soják, P. josephiana H. Ikeda & H. Ohba, P. lineata Trev., P. fallens Card, and P. polyphylla Wall, ex Lehm. are recognized. Potentilla josephiana is a new name for P.fulgens Wall, ex Hook. var. intermedia Hook. f. Four varieties are recognized in P. polyphylla: var. polyphylla; var. himalaka H. Ikeda & H. Ohba, var. nov.; var. interrupta (Yü & Li) H. Ikeda & H. Ohba, stat. & comb, nov.; and var. barbata Lehm. A polyploid series is found in this group. Four putative hybrids between the species are also recognized.     

New polymorphic microsatellite loci,cross‐species amplification and PCR multiplexing in the black aphid,Aphis fabae Scopoli

Aphis fabae includes four morphological cryptic subspecies, which are mostly identified by their partially distinct secondary host range. To determine the extent of gene flow and isolation between these four taxa, we isolated and characterized 12 microsatellite loci from Aphis fabae fabae and tested cross‐species amplification of eight loci from the closely related species Aphis gossypii. Using eight previously described microsatellite loci, we have developed the polymerase chain reaction (PCR) multiplexing of 24 loci, which were separated in tree sets and five PCRs. These sets of microsatellite loci provide high throughput capacity for large‐scale population genetic studies at a minimum cost.     

The life cycle and generic position of Aphis tremulae L., 1761 (Aphidoidea: Pemphiginae), with a description of the viviparous morphs and a discussion of spruce root aphids in the British Isles

An account is given of the biology of Aphis tremulae L., confirming its heteroecy from Populus tremula L. to roots of Picea abies (L.) Karst. The viviparous morphs from both hosts are described. The identity of British aphids from spruce roots is discussed. Aphis tremulae is placed in the genus Pachypappa Koch, of which Astphum Koch becomes a subjective synonym. A key is given to the viviparous morphs of the known British genera of Pemphiginae.     

Determination of aucubin and catalpol in Plantago species by micellar electrokinetic chromatography

Micellar electrokinetic chromatography (MEKC) was used for the separation and determination of two iridoid glycosides, aucubin and catalpol, in several Plantago species growing in Croatia: P. altissima L., P. argentea Chaix, P. coronopus L., P. holosteum Scop. (subsp. depauperata, subsp. holosteum and subsp. scopulorum), P. lagopus L., P. lanceolata L., and P. maritima L. Hot water extraction (HWE) was applied for the isolation of iridoid substances. Significant differences appeared between the iridoid contents in the examined species. The yield of aucubin and catalpol was up to 0.27% and 1.81% of the dry mass of the leaves, respectively. Besides aucubin and catalpol, two related compounds were determined in the plant samples.     

Salt-spray stimulated growth in strand-line species

The response to salt spray and soil salinity of two sand dune strandline species ( Cakile maritima Scop. and Salsola kali L.) and two salt marsh strand-line species ( Atriplex hastata L. and A. littoralis L.) was compared in sand-compost cultures. The growth of the salt-marsh species remained unaffected, while the growth of the sand dune species Cakile maritima was strongly reduced by NaCl (150 and 300 m M ) absorbed via the root system. All four species were resistant to airborne salinity, and under conditions of low soil fertility, salt spray increased the dry matter production, especially of the sand dune species. Mineral analysis revealed foliar uptake of Na, K, Cl, Ca and Mg. Na and Cl ions absorbed from seawater droplets induced succulence. Both salt spray and soil salt increased the methylated quaternary ammonium compound content in the shoot tissue. Under non-saline conditions a considerable amount of these osmotic solutes was still present, while turgor pressure potential in these plants was rather low. The relation between salt, compatible osmotic solutes, turgor pressure potential and growth is discussed. Next to the major constituents of seawater, Na and Cl, especially magnesium and to a lesser extent, calcium, accumulated in the shoot tissue. Based on the positive growth response of the sand dune species to airborne salt, they should be termed 'aerohalophytes', whereas 'soil halophytes' should be used when referring to the Atriplex species, which are more specifically adapted to the increased salinity of salt marsh soils.     

Prey species affects the performance of the aphidophagous ladybird,Coelophora saucia

Performance of ladybird, Coelophora saucia (Mulsant) was studied on seven aphid species in terms of various life attributes. Immature stages developed fastest and survived most on Aphis craccivora. Longevity, fecundity and egg fertility of adults were highest on A. craccivora. Age specific fecundity was triangular in shape with the occurrence of peak oviposition at an early age on A. craccivora and at a later age on Lipaphis erysimi. The net reproductive rate, intrinsic rate of increase, and finite rate of increase of C. saucia were highest on A. craccivora and lowest on L. erysimi. Owing to better performance of C. saucia on A. craccivora, this is considered as the most suitable prey followed by Myzus persicae, Aphis gossypii, Rhopalosiphum maidis, Ceratovacuna silvestrii, Aphis nerii and L. erysimi. It is the first attempt to evaluate prey suitability of this ladybird based on several attributes.     

Some factors influencing the occurrence and site of oviposition by aphidophagous Syrphidae (Diptera)

Syrphids were not deterred from ovipositing on suitable plants by the presence of other syrphid eggs, larvae or larval gut contents. Heavy infestations of Aphis fabae Scop, on bean plants (Viciafaba L.) induced Platycheirus manicatus (Meig.) to lay preferentially on neighbouring uninfested plants. Such behaviour was not found for Syrphus species. Nor did flowers, a source of adult food, stimulate oviposition nearby. The site of oviposition in relation to Brevicoryne brassicae L. on brussels sprouts (Brassicae oleracea gemnifera L.) varied markedly according to species: in similar conditions Syrphus luniger Meig. laid over 50% of its eggs touching aphids and less than 1% on uninfested plants, whereas P. manicatus laid less than 5% touching aphids and over 50% on uninfested plants. Most eggs were laid close to the edge of the leaf, especially by Platycheirus species, e.g. P. scutatus Meig. which laid over 90% within 5 mm of the edge of the leaf.     

Two new species of Potentilla (Rosaceae) from the Intermountain Region of western U.S.A.

Two new species ofPotentilla from the Intermountain West (U.S.A.) are described and illustrated here for the first time.Potentilla cottamii is known only from the higher quartzite slopes of the Pilot Range and the Raft River Mountains of western Box Elder Co., Utah and adjacent Elko Co., Nevada in the Great Basin. It most closely resemblesP. hyparctica, P. robbinsiana, andP. frigida, which may be its closest living relatives.Potentilla angelliae is known only from one collection from a subalpine meadow on Boulder Mountain of the Aquarius Plateau in southern Utah. It most closely resemblesP. crinita, P. subjuga, andP. bicrenata, the first of which is considered to be its closest relative.