Homopteran Insects Research Articles

Preference and effect of gustatory sense on sugar-feeding of fire ants.

BackgroundThe red imported fire ant is one of the notorious species of ants all over the world. Sugar is one of the most important components of food and necessary for the survival of ants. Because more than 70% food of fire ants is honeydew produced by Homopteran insects such as aphids and scales.MethodologyIt is well known that beetles, flies, and honey bees can recognize the sugar taste through their legs and antennae, but in the case of fire ants, no records regarding gustatory sense were published. In the current study, considering the importance of sugar bait, we investigated the gustatory sense of the fire ant workers to sucrose via behavioral sequence and gustatory behavior. First, the feeding sequence (ethogram) of the fire ant workers on most preferred sugar (sucrose) solution was observed and categorized. Secondly, the gustatory behavior of treated fire ant workers (without flagellum and foreleg tarsi treated with HCL solution) was observed on the sucrose solution. In addition, using scanning electron microscopy (SEM) techniques, we identified the possible porous sensilla types on antenna flagellum and foreleg tarsi of fire ant workers.ResultsBased on the results of feeding sequence, foreleg tarsi of workers were the main body appendages in the detection of the sucrose droplet as compared to antennae flagellum and palps. Feeding time of treated workers with HCL solution was significantly decreased on sucrose solution as compared to those workers having no flagellum. While both types of treated workers have less feeding time in comparison to normal workers. Based on the results of feeding sequence analysis and feeding time, it is indicating that the foreleg tarsi of workers play a more important role in the detection of sucrose solution as compared to antennae flagellum. Based on the SEM results, sensilla chaetic, trichoid II, and basiconic I and II have a clear pore at their tip. This study provides a substantial basis for elucidating the gustatory function of antennal and tarsal sensilla on appendages of fire ant workers to sugars and further baits improvement for the management of fire ants.

Population Density of some Insect Pests Infesting Fallen Soft Dates and their Associated Natural Enemies in Giza Governorate, Egypt

This study aimed to determine the population density and survey the insect pests infesting fallen dates fruits of soft cultivars (Zagloul, Samani and Amhat) in Giza Governorate, Egypt and associated natural enemies, parasitoid and predatory species during two successive seasons 2016/2017 & 2017/2018. Ten insect pests belongs to three insect orders (Lepidoptera, Coleoptera, and Homoptera) were recorded. Lepidopterous insects were,Batrachedra amydraula Meyrick (Fam.: Cosmpterigidae), Arenipses sabella Hampson (Fam.: Pyralidae), Ephestia calidella Guenee (Fam. Pyralidae),Ephestia cautella Walker (Fam. Pyralidae), Ectomyelois ceratoniae Zeller (Fam.Pyralidae) and Stathmopoda auriferella (Walker) (Fam. Stathmopodidae). Coleopterous pests were Coccotrypes dactyliperda (Fabricius) Fam. Scolyitldae, Carpophilus spp. (Fam. Nitidulidae) and Oryzaephilus surinamensis Linnaeus (Fam. Silvanidae). The Homopterous insect was Parlatoria blanchardi Targioni (Fam. Diaspididae).one predatory species, Labidura riparia Pallas, (O.:Dermaptera: Fam.: Labiduridae )and one parasitoids species bracon hebetor (Say) (Hymenoptera: Braconidae ) were found. Results showed that there was no significant difference between the numbers of insects in the two years of study or between the three tested cultivars. While there were significant differences between the inspection dates and between the recorded insect's species numbers. In addition, the results showed that the highest average number of the insect species were Carpophilus spp. followed by E. calidella, P. blanchardi and E. cautella respectively. Mean daily temperature &RH had a low and negative effect on insect population density, while there were differences between the insect pests numbers in different date of inspection. In addition, there was a significant difference between the insect pests numbers, which belongs to order Homoptera and each of (Lepidoptera and Coleoptera).Regarding infestation, percentage, there were significant differences between the averages infestation percentage for the three tested cultivars as well as between the two years of study. Bracon hebetor (Say) was the only recorded parasitoid during the period of study. Percentages of parasitism had no significant difference between the two years of the study, while it had a significant difference between the three date palm cultivars.

Plant-feeding phlebotomine sand flies, vectors of leishmaniasis, prefer Cannabis sativa

Blood-sucking phlebotomine sand flies (Diptera: Psychodidae) transmit leishmaniasis as well as arboviral diseases and bartonellosis. Sand fly females become infected with Leishmania parasites and transmit them while imbibing vertebrates' blood, required as a source of protein for maturation of eggs. In addition, both females and males consume plant-derived sugar meals as a source of energy. Plant meals may comprise sugary solutions such as nectar or honeydew (secreted by plant-sucking homopteran insects), as well as phloem sap that sand flies obtain by piercing leaves and stems with their needle-like mouthparts. Hence, the structure of plant communities can influence the distribution and epidemiology of leishmaniasis. We designed a next-generation sequencing (NGS)-based assay for determining the source of sand fly plant meals, based upon the chloroplast DNA gene ribulose bisphosphate carboxylase large chain (rbcL). Here, we report on the predilection of several sand fly species, vectors of leishmaniasis in different parts of the world, for feeding on Cannabis sativa We infer this preference based on the substantial percentage of sand flies that had fed on C. sativa plants despite the apparent "absence" of these plants from most of the field sites. We discuss the conceivable implications of the affinity of sand flies for C. sativa on their vectorial capacity for Leishmania and the putative exploitation of their attraction to C. sativa for the control of sand fly-borne diseases.

Nature's Battalions: Insects as Agricultural Pests in the Early Modern Caribbean

Among the many environmental hazards that challenged European efforts to colonize the early modern Caribbean were insect infestations of one kind or another. Though scholars have long highlighted the dangers associated with mosquitoes and mosquito-borne diseases, they have paid less attention to the impact of insects on agriculture, the economic foundation for empire in the Caribbean. At various times, caterpillars, grasshoppers, or so-called sugar ants (sometimes labeled the “blast”) destroyed fields of sugarcane and other export crops. They also ravaged provision crops, threatening the lives of inhabitants and the stability of colonial societies across the region. Infestations could force planters to abandon one crop in favor of another, sometimes temporarily, but at times permanently. Though insects posed problems from the earliest years of colonization, the threat grew more pronounced as plantation monoculture took hold across much of the Caribbean in the seventeenth and eighteenth centuries. Perhaps the most dramatic infestation occurred in the 1760s and 1770s when swarms of ants and associated homopteran insects devastated sugar fields in Martinique, Grenada, Barbados, and several other islands. Combating insects became an important goal for planters and entomology a necessary science of empire.

Effect of Different Varieties of Cucumber Plants on the Attractive of some Homopterous Insect Pests

The investigation was carried out to study the influence of three varieties of cucumber plant (F1 hybrid Myadine , F1 hybrid Hayal and F1 hybrid Reda) on the population dynamics of aphids, leafhoppers and whitefly insects .The obtained results showed pronounced differences in the population dynamics of these insects on the tested plant varieties. Chemical analysis results recorded a positive relationship between protein ,carbohydrate contents and aforementioned insects infestation in all varieties. While, a reserve relationship was recorded between pH values and insects infestation. According to these results the resistant varieties can be recommended in the integrated pest management programs for depressing all tested piercing - sucking insects on cucumber plants.

FFECTOF BARLEY VARIETIES AND POTASSIUM FERTILIZATION LEVELS ON THE POPULATION OF APHID AND LEAFHOPPER IN RELATION TO PLANT CHEMICAL AND ANATOMICAL CHANGES

Suscep tibility ofthree varieties of barely plants (Giza-123, Giza-2000 and Giza-132) were evaluated toward infestation by aphids and leafhoppers. Also, the effect of potassium fertilization on the chemical content and anatomical compositions in relation to homopterous insect populationat Diarb Nigm locality Sharkia Governorate during 2013/14 and 2014/15 growing seasons. Results showed that Giza-123 is the lowest variety in terms of chemical content (total protein and carbohydrates content) and also found therewas a shortage in the thickness of the anatomical traits measured. These results led to that Giza-123 is considered as the sensitive variety toward infestation by insects with the lowest crop yield. On contrary, Giza-132 records the longest thickness cellwall, lowest infestation insects and the highest crop yield. Chemical analysis showed a positive relationship between total protein, carbohydrate contents and aphids, leafhoppers infestation in different barley varieties, while reverse relationship between pH values and insect infestation. Potassium fertilization by 100 kg potassium sulfate/feddan greatly increased the thickness of the anatomical traits [cuticle and upper epidermis thick. (μ), cuticle and lower epidermis thick. (μ), mesophyll tissue thick.(μ)lamina thick. (μ)] It is noted that, increasing the thickness of upper and/or lower epidermis and their cuticle layers decreased the population density of piercing suckinginsects in blade leaf and increasing mesophyll tissue thickness improve the photosynthesis process which lead to decreasing the adverse effect of insects. which associated with lowering the number of piercing -sucking insects. Thus, potassium fertilization by 100 kg potassium sulfate/feddan is recommended in the integrated pest management control (IPM) on barely plants.

Whitefly speciesand their parasitoids associated with huizache Acacia farnesiana (L.) Willd. (Fabales: Fabaceae) in the Bermejillo area of Durango, Mexico

Se realizaron muestreos de insectos asociados al huizache de marzo a septiembre de 2013, en diez árboles de huizache localizados en la Unidad Regional Universitaria de Zonas Áridas (URUZA) de la Universidad Autónoma Chapingo, ubicada en Bermejillo, Dgo. Se utilizó una aspiradora de insectos tipo D-Vac motorizada modelo 2846 y trampas pegajosas amarillas. El material colectado fue revisado en laboratorio, encontrando en su mayoría insectos homópteros, en particular adultos de mosca blanca y dos grupos de parasitoides. La especie de mosca blanca que afecta al huizache fue Tetraleurodes acaciae (Quaintance) (Homoptera: Aleyrodidae), se registró la dinámica poblacional de este homóptero con base en adultos colectados en 20 cm2 de trampas pegajosas amarillas, registrando la más alta incidencia el 29 de julio con 359 adultos. Se estimó el porcentaje de parasitismo en ninfas por fecha de muestreo, bajo condiciones controladas de temperatura (28 °C) y humedad relativa (30 %). Después de 72 horas se determinó la emergencia, identificando a los parasitoides Eretmocerus sp.(Hymenoptera: Aphelinidae) y Signiphora sp. (Hymenoptera: Signiphoridae). El porcentaje de parasitismo combinado f luctuó de 0 a 62 %,registrándose el porcentaje más alto el 12 de septiembre. Del total delos adultos de parasitoides emergidos, 199 fueron de Eretmocerus sp., los cuales representaron el 67.2 %y 97 fueron de Signiphora sp. (32.8 %). La mosca blancaT. acaciae enel huizache A. farnesiana, es nuevo registro para México. Los dos parasitoides identificados son nuevos registros en huizache para Durango y para la mosca blanca T. acaciae.

Garlic: A potential source of pharmaceuticals and pesticides: A review

Garlic (Allium sativum) holds a unique therapeutic potential as it inhibits invasion of carcinoma, provides cardiovascular protection, lowering of cholesterol, blood pressure, anti-platelet activities, and thromboxane formation. It provides protection against atherosclerosis and associated disorders and helps to decrease serum levels of glucose, insulin, triglycerides, and uric acid, as well as insulin resistance, and reduces cytokine levels. It shows hypolipidemic, anti-platelet, and procirculatory effects, and antimutagenic and antiproliferative properties. It prevents cold and flu symptoms through immune enhancement and exhibits anticancer and chemopreventive activities. The main active component of garlic is alliin (S-allyl cysteine sulfoxide), a potent antioxidant which shows cardioprotective and neuroprotective actions. Diallyl trisulfide, major garlic derivatives, could inhibit the cell proliferation by triggering either cell cycle arrest or apoptosis in a variety of cancer cells. Organosulfur compounds from garlic inhibit the growth of transplanted as well as spontaneous cancers in preclinical animal models without any adverse side effects. Garlic is a good source of anti-invasive, antioxidant, anti-inflammatory, immunomodulatory, chemopreventive, hepatoprotective, antimicrobial, apoptotic, cardioprotective, antidiabetic agents and shows insecticidal effects against lepidopteran, coleopteran, dipteran and homopteran insect pests. Hence, its constituents could be used to develop alternatives to conventional insecticides for control of serious fruit and vegetable pests. Garlic herbal preparations can reduce non-target exposure to hazardous insecticides and curb resistance development in insects. No doubt garlic based different ailments and concoctions can be used to alleviate a variety of health problems. Its various supplements contain a different concentration of organosulfur compounds are available commercially in market

The Effect of Ultraviolet-A Radiation Exposure on the Reproductive Ability, Longevity, and Development of the Dialeurodes citri (Homoptera: Aleyrodidae) F1 Generation.

Ultraviolet (UV) light has been used worldwide to monitor and trap insect pests. Whitefly adults show conspicuous positive phototactic behavior toward UV light stimuli; however, knowledge of the effect of UV light exposure on various life-history parameters of Dialeurodes citri remains limited. The present research aimed to investigate the effect of ultraviolet radiation (UV-A; long-wave) exposure on the reproduction and longevity of D. citri adults as well as the development of immature (eggs, larvae, and pupae) flies in the F1 generation. Paired D. citri adults were exposed to UV-A radiation for different periods (0, 1, 4, and 7 h/d) until the end of their life. The results of the experiment revealed that fecundity and oviposition rates increased when adults were irradiated for 1 and 4 h/d, but interestingly, both were significantly decreased compared with those of the controls after the longest exposure time (7 h/d). The longevity of adults of both sexes and the cumulative survival of F1 immatures were decreased with increased exposure time. Exposure to UV-A radiation prolonged the developmental time of immature stages, and a positive correlation was observed with exposure time. Exposure to UV light significantly inhibited egg hatching, larval development, pupation, and adult emergence. To the best of our knowledge, this is the first study describing the effect of UV radiation on a homopteran insect pest. This research may provide a foundation for the scientific community to use UV light in the field as an integrated pest management strategy to control this devastating agricultural pest.

Extended Survival of Spiders (Aranaeae) Feeding on Whitefly (Homoptera: Aleyrodidae) Honeydew

Abstract Honeydew produced by homopteran insects, such as aphids, whiteflies, and mealybugs, can be abundant in some crops and may represent an important food resource for spiders and other honeydew-feeding natural enemies. Woolly whiteflies (Aleurothrixus floccosus [Homoptera: Aleyrodidae]) are common in south Texas citrus, and spiders consistently compose a large percentage of the predatory arthropods in citrus and may benefit from honeydew resources. Feeding on woolly whitefly honeydew was assayed for its contribution to spider survival for five species from different arachnid families. When provided with whitefly honeydew, survival of all five species was significantly better than when provided water alone. However, the level of improvement in survival varied significantly among species. Honeydew supplementation increased survival by 73.5% for Apollophanes punctipes (Cambridge, O. P) (Philodromidae) (32.1 versus 18.5 d on water alone), 266.7% for Cesonia bilineata (Hentz) (Gnaphosidae), 352.6% for Di...

Identification, expression profiling and fluorescence-based binding assays of a chemosensory protein gene from the Western flower thrips, Frankliniella occidentalis.

Using RT-PCR and RACE-PCR strategies, we cloned and identified a new chemosensory protein (FoccCSP) from the Western flower thrips, Frankliniella occidentalis, a species for which no chemosensory protein (CSP) has yet been identified. The FoccCSP gene contains a 387 bp open-reading frame encoding a putative protein of 128 amino acids with a molecular weight of 14.51 kDa and an isoelectric point of 5.41. The deduced amino acid sequence contains a putative signal peptide of 19 amino acid residues at the N-terminus, as well as the typical four—cysteine signature found in other insect CSPs. As FoccCSP is from a different order of insect than other known CSPs, the GenBank FoccCSP homolog showed only 31-50% sequence identity with them. A neighbor-joining tree was constructed and revealed that FoccCSP is in a group with CSPs from Homopteran insects (e.g., AgosCSP4, AgosCSP10, ApisCSP, and NlugCSP9), suggesting that these genes likely developed from a common ancestral gene. The FoccCSP gene expression profile of different tissues and development stages was measured by quantitative real-time PCR. The results of this analysis revealed this gene is predominantly expressed in the antennae and also highly expressed in the first instar nymph, suggesting a function for FoccCSP in olfactory reception and in particular life activities during the first instar nymph stage. We expressed recombinant FoccCSP protein in a prokaryotic expression system and purified FoccCSP protein by affinity chromatography using a Ni-NTA-Sepharose column. Using N-phenyl-1-naphthylamine (1-NPN) as a fluorescent probe in fluorescence-based competitive binding assay, we determined the binding affinities of 19 volatile substances for FoccCSP protein. This analysis revealed that anisic aldehyde, geraniol and methyl salicylate have high binding affinities for FoccCSP, with KD values of 10.50, 15.35 and 35.24 μM, respectively. Thus, our study indicates that FoccCSP may play an important role in regulating the development of the first instar nymph and mediate F. occidentalis host recognition.

Factors associated with the distribution and size of Adelges abietis (Homoptera: Adelgidae) galls on a sev- eral years old spruce (Picea abies) plantation

The eastern spruce gall adelgid (Adelges abietis) is a homopteran insect related to aphids. It forms pineapple-like pseudocone galls on Norway spruce (Picea abies) shoots, which are often deformed by them. The factors responsible for gall distribution within a tree crown are not clear. We investigated the distribution of galls in crowns on a spruce plantation. We assumed that the number and size of galls is dependent on the size of the tree, position on the crown, the type of shoot and its placement relative to the compass points. We also counted the larval chambers and related their number with gall size. We demonstrated that the largest galls are in the upper part of the crown and on the lateral shoots, and the number of chambers is closely related to the size of the galls. The level of shoot embrace has a significant impact on shoot deformation.

Molecular biology and pathogenicity of phytoplasmas

AbstractPhytoplasmas are a large group of plant‐pathogenic wall‐less, non‐helical, bacteria associated with diseases, collectively referred to as yellows diseases, in more than a thousand plant species worldwide. Many of these diseases are of great economic importance. Phytoplasmas are difficult to study, in particular because all attempts at culturing these plant pathogens under axenic conditions have failed. With the introduction of molecular methods into phytoplasmology about two decades ago, the genetic diversity of phytoplasmas could be elucidated and a system for their taxonomic classification based on phylogenetic traits established. In addition, a wealth of information was generated on phytoplasma ecology and genomics, phytoplasma–plant host interactions and phytoplasma–insect vector relationships. Taxonomically, phytoplasmas are placed in the class Mollicutes, closely related to acholeplasmas, and are currently classified within the provisional genus ‘Candidatus Phytoplasma’ based primarily on 16S rDNA sequence analysis. Phytoplasmas are characterised by a small genome. The sizes vary considerably, ranging from 530 to 1350 kilobases (kb), with overlapping values between the various taxonomic groups and subgroups, resembling in this respect the culturable mollicutes. The smallest chromosome, about 530 kb, is known to occur in the Bermuda grass white leaf agent ‘Ca. Phytoplasma cynodontis’. This value represents the smallest mollicute chromosome reported to date. In diseased plants, phytoplasmas reside almost exclusively in the phloem sieve tube elements and are transmitted from plant to plant by phloem‐feeding homopteran insects, mainly leafhoppers and planthoppers, and less frequently psyllids. Most of the phytoplasma host plants are angiosperms in which a wide range of specific and non‐specific symptoms are induced. Phytoplasmas have a unique and complex life cycle that involves colonisation of different environments, the plant phloem and various organs of the insect vectors. Furthermore, many phytoplasmas have an extremely wide plant host range. The dynamic architecture of phytoplasma genomes, due to the occurrence of repetitive elements of various types, may account for variation in their genome size and adaptation of phytoplasmas to the diverse environments of their plant and insect hosts. The availability of five complete phytoplasma genome sequences has made it possible to identify a considerable number of genes that are likely to play major roles in phytoplasma–host interactions. Among these, there are genes encoding surface membrane proteins and effector proteins. Also, it has been shown that phytoplasmas dramatically alter their gene expression upon switching between plant and insect hosts.

Comparative Neuroanatomy of the Antennal Lobes of 2 Homopteran Species

We compared the morphology of the primary olfactory center, the antennal lobe (AL), in 2 homopteran insects, Hyalesthes obsoletus Signoret (Homoptera: Cixiidae) and Scaphoideus titanus Ball (Homoptera: Cicadomorpha). The comparison between the ALs of the 2 species is particularly interesting considering that, although both use volatile cues to locate their host plants, their feeding behavior differs considerably: specifically, H. obsoletus is a highly polyphagous species, whereas S. titanus is strictly monophagous (on grapevine). Our investigation of the AL structure using immunocytochemical staining and antennal backfills did not reveal any sexual dimorphism in either the size of the ALs or in the size of individual glomeruli for either species. Instead, the AL of H. obsoletus displayed numerous and well-delineated glomeruli (about 130 in both sexes) arranged in a multilayered structure, whereas the smaller AL of S. titanus contained fewer than 15 glomerular-like structures. This difference is likely to reflect the comparatively reduced olfactory abilities in S. titanus, probably as a consequence of the reduced number of volatiles coming from the single host plant. Instead, in H. obsoletus, the ability to distinguish among several host plants may require a more complex olfactory neuronal network.

Homopteran Vector Biomarkers for Efficient Circulative Plant Virus Transmission are Conserved in Multiple Aphid Species and the Whitefly Bemisia tabaci

Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent, circulative manner by homopteran insects. Using fluorescence 2-D difference gel electrophoresis to compare the proteomes of F2 genotypes of Schizaphis graminum segregating for virus transmission ability, we recently discovered a panel of protein biomarkers that predict vector competency. Here we used aphid and whitefly nucleotide and expressed sequence tag database mining to test whether these biomarkers are conserved in other homopteran insects. S. graminum gene homologs that shared a high degree of predicted amino acid identity were discovered in two other aphid species and in the whitefly Bemisia tabaci. Selected reaction monitoring mass spectrometry was used to validate the expression of these biomarkers proteins in multiple aphid vector species. The conservation of these proteins in multiple insect taxa that transmit plant viruses along the circulative transmission pathway creates the opportunity to use these biomarkers to rapidly identify insect populations that are the most efficient vectors and allow them to be targeted for control prior to the spread of virus within a crop.

Phytoplasmas: colonizing agents of plant phloem and insects

Plant-pathogenic phytoplasmas are wall-less, unculturable bacteria of the class Mollicutes that are associated with diseases, collectively referred to as yellows diseases, in more than a thousand plant species worldwide. Many of these diseases are of great economic importance. Phytoplasmas reside in the phloem sieve tubes and are transmitted from plant to plant by phloem-feeding homopteran insects, mainly leafhoppers (Cicadellidae) and planthoppers (Fulgoromorpha), and less frequently psyllids (Psyllidae). Most of the host plants of phytoplasmas are angiosperms in which a wide range of specific and non-specific symptoms are induced. Phytoplasmas, which are phylogenetically more closely related to acholeplasmas than to other mollicutes, have a complex life cycle that involves colonization of different environments, the plant phloem and various organs of the insect vectors. The dynamic architecture of phytoplasma genomes may account for variation in their genome size and adaptation to the diverse environments of their plant and insect hosts. Newly acquired knowledge has made it possible to identify a considerable number of phytoplasma genes that are likely to play major roles in phytoplasma-host interactions. Among these, there are genes encoding surface membrane proteins and effector proteins. Also, it has been shown that phytoplasmas dramatically alter their gene expression upon switching between plant and insect hosts.

Arthropod invasion disrupts Cycas micronesica seedling recruitment

We recently described characteristics of reproductive effort for the cycad Cycas micronesica on the island of Guam. The data were serendipitously recorded just prior to the devastating invasion of the armored scale Aulacaspis yasumatsui. This invasion decimated the cycad population and after six years of infestation no recruitment is occurring among the survivors. We describe various underlying mechanisms that may explain how this homopteran insect has eliminated host recruitment among categories including plant-pollinator mutualism disruptions, direct damage to reproductive structures, population level responses to declining plant health, and failures of seedlings to establish. Our pre-invasion data on reproductive effort will serve as the benchmark for quantifying how this alien pest is endangering the endemic cycad.

Leaf disk transformation of Lactuca sativa using Agrobacterium tumefaciens.

Reliable methods of transferring cloned genes into plants are essential for engineering crops with desired traits. In order to induce sap-sucking insect resistance Agrobacterium tumefaciens LBA 4404 (1065) strain containing the binary vector pMOG 23 and hypervirulent pTOK 47 plasmid was used. pta (Pinellia ternata agglutinin), salmon ct (calcitonin) and cgrp (calcitonin gene related protein) genes were successfully integrated into Lactuca sativa plants. This genetic modification conferred lettuce resistance to orthopteran and homopteran insects like Nilaparvata lugens Stl or Myzus persicae Sulzer. Lactuca sativa could be routinely transformed using Ti plasmids of A. tumefaciens containing a chimeric kanamycin resistance gene (nos nptII. nos).

Isolation and identification of culturable forms of bacteria from the sweet potato whitefly Bemesia tabaci Genn. (Homoptera: Aleyrodidae) in Jordan

Homopteran insects contain bacteria in their cells and tissues known as "secondary symbionts," which under special environmental circumstances act against their host insects. In this study, both molecular- and culture-based methods were used to characterize the bacteria associated with the whitefly in Jordan. We isolated, cultured, and identified 11 species of bacteria from nymphs (6 species), adults (8 species), and parasitized pupae (2 species) of the whitefly Bemesia tabaci collected from different vegetable crops planted in different localities in Jordan. The identities of the cultured bacteria were evaluated using PCR with sequencing of 16S rRNA gene fragments and fluorescence in situ hybridization. Three gram-negative bacteria were identified as Erwinia persicinus, Pseudomonas plecoglossicida, and Pseudomonas putida. The identified gram-positive bacteria included Brevibacterium casei, Staphylococcus gallinarum, Bacillus pumilus, Bacillus licheniformis, Bacillus subtilis, Exiquobacterium acetylicum, Exiguobacterium undae, and Micrococcus caseolyticus.

Biological consequences of invasion by reed canary grass (Phalaris arundinacea)

Although they are typically assumed to be negative, the consequences of plant invasions for native diversity or biological integrity are seldom broadly quantified (i.e., for multiple taxa or across large regions). We investigated the impacts associated with invasion of wetlands by reed canary grass (Phalarisarundinacea L.; RCG) on plants and several animal groups. In a local study, we compared plants, arthropods, and small mammals on treatment plots with reduced RCG dominance to those on highly invaded plots. We also conducted a companion study, where we measured RCG dominance and plants, arthropods, and birds in 82 randomly selected wetlands across Illinois (USA) to determine if our experimental results were consistent in communities across the region. Plant diversity, floristic quality, and diversity and abundance of Homopteran insects decreased with RCG dominance in all instances. Richness and abundance of all other arthropods decreased with increasing RCG in the local study, but no trend was detected in communities statewide. No relationship between total abundance or richness of small mammals (local) or birds (statewide) with RCG was detected. However, voles and shrews were more abundant, and mice less abundant, in RCG-dominated plots. These results support the hypothesis that there are negative effects for multiple taxa from RCG invasion. Because negative effects observed in the local study either corroborated, or were neutral with respect to results from statewide surveys, they suggest that native biodiversity and biological integrity are being dampened across wide areas of this invader’s range.