Main Components of Spider Venoms

Venom glands are alreadypresent in theoldes t spider group, the Mesothelae. Theglands lie in the anterior portion of the cheliceral basal segment but are very small, and it is doubtful how much the venom contributes to the predatory success. In mygalomorph spiders, the well-developed venom glands are still in the basal segment of the chelicerae and produce powerful venom that is injected via the cheliceral fangs into a victim. In all other spiders (Araneomorphae), the venom glands have become much larger and reach into the prosoma where they can take up a considerable proportion of this body part. Only a few spiders have reduced their venom glands, either partially or completely (Uloboridae, Holarchaeidae and Symphytognathidae are usually mentioned) or modified them significantly (Scytodidae, see Suter and Stratton 2013). As well as using venom, spiders may also use their chelicerae to overwhelm an item of prey. It is primarily a question of size whether a spider chews up small arthropods without applying venom or if it injects venom first. Very small and/or defenceless arthropods are picked up and crashed with the chelicerae, while larger, dangerous or well-defended items are carefully approached and only attacked with venom injection. Some spiders specialize on prey groups, such as noctuid moths (several genera of bola spiders among Araneidae), web spiders (Mimetidae), ants (Zodarion species in Zodariidae, aphantochiline thomisids, several genera among Theridiidae, Salticidae, Clubionidae and Gnaphosidae) or termites (Ammoxenidae). However, these more or less monophagous species amount only to roughly 2 % of all known spider species, while 98 % are polyphagous. From these considerations, it follows that the majority of spider venoms are not tailored to any given invertebrate or insect group but are rather unspecialized to be effective over a broad spectrum of prey types that spiders naturally encounter.

Is fern endozoochory widespread among fern-eating herbivores?

Endozoochory is an important dispersal mechanism for seed plants and has recently been demonstrated to occur also in spore plants, such as ferns, which are commonly consumed by herbivores. However, it is not known whether fern species from particular habitats are differentially preferred by herbivores and whether their spores differ in their ability to survive the gut passage of herbivores. Such differences would suggest adaptation to endozoochorous dispersal, as it is known for seed plants. Moreover, it is unclear whether herbivore species differ in their efficiency to disperse fern spores. In a factorial experiment, we fed fertile leaflets of 13 fern species from different forest and open habitats to three polyphagous herbivore species and recorded the germination of spores from feces after 46 and 81 days. Fern spores germinated in 66 % of all samples after 46 days. At this stage, germination success differed among fern and herbivore species, but was independent of the ferns’ habitat. Interestingly, after 81 days fern spores germinated in 85 % of all samples and earlier significant differences in germination success among fern and herbivore species were not sustained. The overall high germination success and the absence of differences among fern species from different habitats together with the consistency across three tested herbivores strongly imply endozoochorous dispersal to be a taxonomically widespread phenomenon among fern-eating herbivores, which all might act as potential dispersal vectors. © 2015, Springer Science+Business Media Dordrecht.

Comparación a campo de distintos cultivares de olivo (Olea europaea L.) como hospedadores de Siphoninus phillyreae (Haliday)

La mosca blanca del fresno, Siphoninus phillyreae (Haliday) , es una especie polífaga invasiva que causa graves daños en sus hospedadores, entre ellos el olivo (Olea europaea L.). El uso del hospedador por parte de S. phillyreae fue observado en tres cultivares de olivo (Arauco, Arbequina y Aloreña) en el norte de la provincia de La Rioja (Argentina) durante 2007 y 2008. De cada cultivar se muestrearon seis plantas infestadas y de cada planta se tomaron ocho hojas. De cada hoja se registró la abundancia de adultos y estados inmaduros de la mosca blanca que fueron comparadas entre los cultivares mediante modelos lineales generales y mixtos. Los resultados obtenidos mostraron diferencias significativas entre las densidades de adultos y ninfas de S. phillyreae en los distintos cultivares de olivo analizados. Dichos resultados indican que este insecto realiza un uso diferente de los cultivares de olivo, siendo Arauco y Arbequina las variedades hospedadoras más utilizadas en la zona de estudio.

Side effects of modern pesticides on adults of the predatory mite Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) under laboratory conditions

Amblyseius swirskii (Athias-Henriot) is a polyphagous predatory mite which feeds on pollen and small arthropod preys like whiteflies, thrips and mites. This species is widely used in IPM programs in greenhouses, being essential for its success, to obtain information about the non target effects of the pesticides currently used in those crops where the mite is artificially released. This work describes a laboratory contact residual test for evaluating lethal (mortality after 72 hour exposure to fresh residues) and sublethal effects (fecundity and fertility of the surviving mites) of eleven modern pesticides to adults of A. swirskii. Spiromesifen is lipogenesis inhibitor; flonicamid a selective feeding inhibitor with a mode of action not totally known; flubendiamide a modulator of the rhyanodin receptor, sulfoxaflor has a complex mode of action not totally ascertained; metaflumizone is a voltage dependent sodium channel blocker; methoxyfenozide is an IGR, spirotetramat inhibits lipids; abamectin and emamectin activate the Cl- channel; spinosad is a neurotix naturalyte and deltamethrin a pyrethroid used as positive standard. Selected pesticides are effective against different key pests present in horticultural crop areas and were always applied at the maximum field recommended concentration in Spain if registered, or at the concentration recommended by the supplier. Out of the tested pesticides, spiromesifen, flonicamid, flubendiamide, sulfoxaflor, metaflumizone, methoxyfenozide and spirotetramat were harmless to adults of the predatory mite (IOBC toxicity class 1). The rest of pesticides exhibited some negative effects: emamectin was slightly harmful (IOBC 2), deltamethrin moderately harmful (IOBC 3) and spinosad and abamectin harmful (IOBC 4). Further testing under more realistic conditions is needed for those pesticides having some harmful effect on the mite prior deciding their joint use or not. Key words: Amblyseius swirskii, adults, laboratory, residual test, spiromesifen, flonicamid, flubendiamide, sulfoxaflor, metaflumizone, methoxyfenozide, spirotetramat, emamectin, deltamethrin, abamectin, spinosad.

Macroevolution of insect–plant associations: The relevance of host biogeography to host affiliation

Identifying the factors that have promoted host shifts by phytophagous insects at a macroevolutionary scale is critical to understanding the associations between plants and insects. We used molecular phylogenies of the beetle genus Blepharida and its host genus Bursera to test whether these insects have been using hosts with widely overlapping ranges over evolutionary time. We also quantified the importance of host range coincidence relative to host chemistry and host phylogenetic relatedness. Overall, the evolution of host use of these insects has not been among hosts that are geographically similar. Host chemistry is the factor that best explains their macroevolutionary patterns of host use. Interestingly, one exceptional polyphagous species has shifted among geographically close chemically dissimilar plants.

A synthetic cryIC gene, encoding a Bacillus thuringiensis δ-endotoxin, confers Spodoptera resistance in alfalfa and tobacco

Spodoptera species, representing widespread polyphagous insect pests, are resistant to Bacillus thuringiensis δ-endotoxins used thus far as insecticides in transgenic plants. Here we describe the chemical synthesis of a cryIC gene by a novel template directed ligation–PCR method. This simple and economical method to construct large synthetic genes can be used when routine resynthesis of genes is required. Chemically phosphorylated adjacent oligonucleotides of the gene to be synthesized are assembled and ligated on a single-stranded, partially homologous template derived from a wild-type gene (cryIC in our case) by a thermostable Pfu DNA ligase using repeated cycles of melting, annealing, and ligation. The resulting synthetic DNA strands are selectively amplified by PCR with short specific flanking primers that are complementary only to the new synthetic DNA. Optimized expression of the synthetic cryIC gene in alfalfa and tobacco results in the production of 0.01–0.2% of total soluble proteins as CryIC toxin and provides protection against the Egyptian cotton leafworm (Spodoptera littoralis) and the beet armyworm (Spodoptera exigua). To facilitate selection and breeding of Spodoptera-resistant plants, the cryIC gene was linked to a pat gene, conferring resistance to the herbicide BASTA.

Culturable aerobic and facultative bacteria from the gut of the polyphagic dung beetle Thorectes lusitanicus Jeckel

Unlike other dung beetles, the Iberian geotrupid Thorectes lusitanicus exhibits polyphagous behavior; for example, it is able to eat acorns, fungi, fruits, and carrion in addition to the dung of different mammals. This adaptation to digest a wider diet has physiological and developmental advantages and requires key changes in the composition and diversity of the beetle's gut microbiota. In this study, we isolated aerobic, facultative anaerobic, and aerotolerant microbiota amenable to grow in culture from the gut contents of T. lusitanicus and resolved isolate identity to the species level by sequencing 16S rRNA gene fragments. Using BLAST similarity searches and maximum likelihood phylogenetic analyses, we were able to reveal that the analyzed fraction (culturable, aerobic, facultative anaerobic, and aerotolerant) of beetle gut microbiota is dominated by the phyla Proteobacteria, Firmicutes and Actinobacteria. Among Proteobacteria, members of the order Enterobacteriales (Gammaproteobacteria) were the most abundant. The main functions associated with the bacteria found in the gut of T. lusitanicus would likely include nitrogen fixation, denitrification, detoxification, and diverse defensive roles against pathogens.

Intra-specific variation for host plant use in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae): Implications for management

The polyphagous moth Helicoverpa armigera (Hubner) is one of the world's most important agricultural pests. A number of existing approaches and future designs for management of H. armigera rely on the assumption that moths do not exhibit either genetically and/or non-genetically based variation for host plant utilization. We review recent empirical evidence demonstrating that both these forms of variation influence host plant use in this moth. The significance of this variation in H. armigera in relation to current and future pest management strategies is examined. We provide recommendations on future research needs and directions for sustainable management of H. armigera, under a framework that includes consideration of intra.-specific variation for host use relevant in this and other similar pest species. (C) 2004 Elsevier Ltd. All rights reserved.

Foraging behaviour of Helicoverpa armigera first instar larvae on crop plants of different developmental stages

Understanding how insect pests forage on their food plants can help optimize management strategies. Helicoverpa armigera (Hubner) (Lep., Noctuidae) is a major polyphagous pest of agricultural crops worldwide. The immature stages feed and forage on crops at all stages of plant development, damaging fruiting and non-fruiting structures, yet very little is known about the influence of host type or stage on the location and behaviour of larvae. Through semi-continuous observation, we evaluated the foraging (movement and feeding) behaviours of H. armigera first instar larvae as well as the proportion of time spent at key locations on mungbean [Vigna radiata (L.) Wilczek] and pigeon pea [Cajanus cajan (L.) Millspaugh] of differing developmental stages: seedling- and mature (flowering/pod fill)-stage plants. Both host type and age affected the behaviour of larvae. Larvae spent more time in the upper parts of mature plants than on seedlings and tended to stay at the top of mature plants if they moved there. This difference was greater in pigeon pea than in mungbean. The proportion of time allocated to feeding on different parts of a plant differed with host and age. More feeding occurred in the top of mature pigeon pea plants but did not differ between mature and seedling mungbean plants. The duration of key behaviours did not differ between plant ages in either crop type and was similar between hosts although resting bouts were substantially longer on mungbeans. Thus a polyphagous species such as H. armigera does not forage in equivalent ways on different hosts in the first instar stage.

Ecology of Leptocoris Hahn (Hemiptera: Rhopalidae) Soapberry Bugs in Australia

Soapberry bugs are worldwide seed predators of plants in the family Sapindaceae. Australian sapinds are diverse and widespread, consisting of about 200 native trees and shrubs. This flora also includes two introduced environmental weeds, plus cultivated lychee (Litchi chinensis Sonn.), longan (Dimocarpus longan Lour.) and rambutan (Nephelium lappaceum L.). Accordingly, Australian soapberry bugs may be significant in ecology, conservation and agriculture. Here we provide the first account of their ecology. We find five species of Leptocoris Hahn in Australia, and list sapinds that do and do not serve as reproductive hosts. From museum and field records we map the continental distributions of the insects and primary hosts. Frequency of occupation varies among host species, and the number of hosts varies among the insects. In addition, differences in body size and beak length are related to host use. For example, the long-beaked Leptocoris tagalicus Burmeister is highly polyphagous in eastern rainforests, where it occurs on at least 10 native and non-native hosts. It aggregates on hosts with immature fruit and commences feeding before fruits dehisce. Most of its continental range, however, matches that of a single dryland tree, Atalaya hemiglauca F. Muell., which has comparatively unprotected seeds. The taxon includes a smaller and shorter-beaked form that is closely associated with Atalaya, and appears to be taxonomically distinct. The other widespread soapberry bug is the endemic Leptocoris mitellatus Bergroth. It too is short-beaked, and colonises hosts phenologically later than L. tagalicus, as seeds become more accessible in open capsules. Continentally its distribution is more southerly and corresponds mainly to that of Alectryon oleifolius Desf. Among all host species, the non-native environmental weeds Cardiospermum L. and Koelreuteria Laxm. are most consistently attacked, principally by L. tagalicus. These recent host shifts have biocontrol implications. In contrast, the sapinds planted as fruit crops appear to be less frequently used at present and mainly by the longer-beaked species.

Soybean Stem Fly, Melanagromyza sojae (Diptera: Agromyzidae), in the New World: detection of high genetic diversity from soybean fields in Brazil

Soybean Stem Fly (SSF), Melanagromyza sojae (Zehntner), belongs to the family Agromyzidae and is highly polyphagous, attacking many plant species of the family Fabaceae, including soybean and other beans. SSF is regarded as one of the most important pests in soybean fields of Asia (e.g., China, India), North East Africa (e.g., Egypt), parts of Russia, and South East Asia. Despite reports of Agromyzidae flies infesting soybean fields in Rio Grande do Sul State (Brazil) in 1983 and 2009 and periodic interceptions of SSF since the 1940s by the USA quarantine authorities, SSF has not been officially reported to have successfully established in the North and South Americas. In South America, M. sojae was recently confirmed using morphology and its complete mitochondrial DNA (mtDNA) was characterized. In the present study, we surveyed the genetic diversity of M. sojae, collected directly from soybean host plants, using partial mtDNA cytochrome oxidase I (COI) gene, and provide evidence of multiple (>10) maternal lineages in SSF populations in South America, potentially representing multiple incursion events. However, a single incursion involving multiple-female founders could not be ruled out. We identified a haplotype that was common in the fields of two Brazilian states and the individuals collected from Australia in 2013. The implications of SSF incursions in southern Brazil are discussed in relation to the current soybean agricultural practices, highlighting an urgent need for better understanding of SSF population movements in the New World, which is necessary for developing effective management options for this significant soybean pest. © FUNPEC-RP.

Zmienność genetyczna, specyficzność żywicielska i zdolność do przenoszenia wirusa mozaiki smugowatej pszenicy (WSMV) w obrębie kompleksu gatunków Aceria tosichella

Wydział Biologii: Instytut Biologii Środowiska

Life-history traits of Spodoptera frugiperda populations exposed to low-dose Bt maize.

Exposure to Bacillus thuringiensis (Bt) toxins in low- and moderate-dose transgenic crops may induce sublethal effects and increase the rate of Bt resistance evolution, potentially compromising control efficacy against target pests. We tested this hypothesis using the fall armyworm Spodoptera frugiperda, a major polyphagous lepidopteran pest relatively tolerant to Bt notorious for evolving field-relevant resistance to single-gene Bt maize. Late-instar larvae were collected from Bt Cry1Ab and non-Bt maize fields in five locations in Brazil, and their offspring was compared for survival, development, and population growth in rearing environment without and with Cry1Ab throughout larval development. Larval survival on Cry1Ab maize leaves varied from 20 to 80% among the populations. Larvae reared on Cry1Ab maize had seven-day delay in development time in relation to control larvae, and such delay was shorter in offspring of armyworms from Cry1Ab maize. Population growth rates were 50?70% lower for insects continuously exposed to Cry1Ab maize relative to controls, showing the population-level effect of Cry1Ab, which varied among the populations and prior exposure to Cry1Ab maize in the field. In three out of five populations, armyworms derived from Bt maize reared on Cry1Ab maize showed higher larval weight, faster larval development and better reproductive performance than the armyworms derived from non-Bt maize, and one of these populations showed better performance on both Cry1Ab and control diets, indicating no fitness cost of the resistance trait. Altogether, these results indicate that offspring of armyworms that developed on field-grown, single-gene Bt Cry1Ab maize had reduced performance on Cry1Ab maize foliage in two populations studied, but in other three populations, these offspring had better overall performance on the Bt maize foliage than that of the armyworms from non-Bt maize fields, possibly because of Cry1Ab resistance alleles in these populations. Implications of these findings for resistance management of S. frugiperda in Bt crops are discussed.

Avaliação da potencial migração de Helicoverpa armigera (Lepidoptera: Noctuidae) por massas de ar para áreas produtoras de cultivos hospedeiros do Estado de São Paulo.

Resumo Helicoverpa armigera (Hübner, 1808) (Lepidoptera: Noctuidae) é um inseto exótico, altamente polífago, que foi detectado no Brasil em 2013 causando sérios danos em cultivos de soja, milho e algodão, localizados em áreas estaduais específicas das regiões Nordeste e Centro-Oeste com a presença do bioma Cerrado. Após o período de um ano o inseto foi identificado em várias regiões do País. A literatura indica que o inseto adulto apresenta características físicas que favorecem sua grande capacidade de voo, tanto em distância (100-1000 km) quanto a elevadas altitudes (maiores que 1,5 km acima do nível do solo), aumentando o seu potencial para dispersão de longo alcance, principalmente por voos migratórios das áreas já atacadas. Por essa razão, as massas de ar brasileiras podem atuar como potenciais facilitadoras à atividade migratória do inseto a longas distâncias para as áreas de maior concentração de seus cultivos hospedeiros preferenciais, resultante da atração natural do inseto aos fatores químicos delas decorrentes. Desse modo, devem ser consideradas em avaliações de áreas mais propícias à presença de H. armigera para orientar monitoramentos e estratégias de manejo locais. Este trabalho avaliou a potencial migração de H. armigera por massas de ar para áreas produtoras de cultivos hospedeiros do estado de São Paulo, considerando seus municípios produtores de algodão, soja, milho, tomate, feijão, café e laranja; as principais massas de ar brasileiras; a presença de grandes áreas com cultivos de eucalipto e pinus (outras potenciais barreiras físicas ao inseto); e a localização do bioma Cerrado paulista. Informações das áreas produtoras e das áreas plantadas por município de 2008, 2012 e 2014, disponibilizadas pelo IBGE, foram utilizadas em planos de informação georreferenciados, elaborados em ArcGis 10.3, para identificar a localização de suas respectivas grandes áreas em cada ano. O cruzamento georreferenciado também resultou mapas das áreas plantadas em 2014 com todos os cultivos citados, indicando as de maior potencial de infestação/reinfestações de H. armigera no estado de São Paulo, para orientar monitoramentos e estratégias de Manejo Integrado de Pragas - MIP locais. Abstract Helicoverpa armigera (Hübner, 1808) (Lepidoptera: Noctuidae) is an exotic insect highly polyphagous, which was detected in Brazil in 2013 causing serious damage to soybean, corn and cotton crops located in specific state areas in the northeast and center-west regions with the presence of Cerrado Biome (similar to the Savannah). After a oneyear period, the insect was detected in several regions of the country. Foreign literature indicates that the adult phase of the insect shows certain physical characteristics which favor its great flight capacity, even related to reach long distances (100-1000 Km) as many as to reach high altitudes (overtaken 1.5 Km above the ground level), increasing its potential of farthest dispersion, mainly by migratory flights from the areas already attacked. Therefore, the Brazilian air masses may act as potentially enhance the insect's farthest migratory activity to areas of greater concentration of its preferential host crops due to the insect's natural attraction to their chemical factors. Thus, migration potential of H. armigera by air masses toward preferential host crop areas must be considered in evaluations of most favorable areas to the presence of the insect to guide monitoring and local management strategies. The present work evaluated the H. armigera migration potential by air masses toward producing areas of host crops in São Paulo state, Brazil, considering its municipalities producing cotton, soybean, corn, tomato, bean, coffee, orange, eucalyptus and pine trees, as well as the main Brazilian air masses and the presence of Cerrado Biome in the state. Information of producing and of planting areas with the annual crops by municipalities in 2008, 2012 and 2014, provided by IBGE, were used in cross-maps made using ArcGis 10.3, in order to identify the location of their respective greater areas in each year. Cross-maps also provided results indicating the planting areas in 2014 with all crops already mentioned, as well as the potential areas to infestation/reinfestations of H. armigera in São Paulo State, in order to guide monitoring and local strategies of IPM.

Timeline and geographical distribution of Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae: Heliothinae) in Brazil.

Abstract This study presents registers of Helicoverpa armigera (Hübner) occurrence to assess its spatial and temporal distribution in Brazil. We used data from collections, especially from the Southern Region, systematic collections in Rio Grande do Sul, occasional collections of caterpillars and adults in different regions of Brazil, as well as literature registers. We conclude that the introduction of H. armigera in Brazil probably occurred before October 2008. We also register that in August 2012 H. armigera was already present from the extreme southern part (Rio Grande do Sul) to the extreme northern part (Amapá) of Brazil.