Pachycondyla obscuricornis as natural enemy of the spittlebug Deois flavopicta

The objective of this work was to evaluate the potential control of the ant Pachycondyla obscuricornis Emery (Hymenoptera Formicidae) on populations of nymphs of the spittlebug, Deois flavopicta Stal (Hemiptera Cercopidae). Foraging behavior and prey consumption rate of P. obscuricornis were evaluated. Field data revealed that P. obscuricornis does not show aggressive behavior against individuals of the same species, when they are not carrying a prey; they can patrol distances larger than 10 m searching for prey, and they can build their nest as close as 1 m from each other. The ant has a solitary patrolling habit, there is no recruitment behavior, and individuals dislocate fast, browsing on soil and vegetation for prey. Predation rate on spittlebug nymphs increased relative to the spittlebug abundance, reaching 93.8% of captured prey. Pachycondyla obscuricornis is a voracious predator and may control the population of spittlebugs in cultivated pastures.

Oviposition-induced changes in Arabidopsis genome expression: anticipating your enemy?

Plants have evolved exquisite ways to detect their enemies and are able to induce defenses responses tailored to their specific aggressors. Insect eggs deposited on a leaf represent a future threat as larvae hatching from the egg will ultimately feed on the plant. Although direct and indirect defenses towards oviposition have been documented, our knowledge of the molecular changes triggered by egg deposition is limited. Using a whole-genome microarray, we recently analyzed the expression profile of Arabidopsis thaliana leaves after oviposition by two pierid butterflies. Eggs laid by the large white Pieris brassicae modified the expression of hundreds of genes. The transcript signature included defense and stress-related genes that were also induced in plants experiencing localized cell death. Further analyses revealed that cellular changes associated with a hypersensitive response occur at the site of egg deposition and that they are triggered by egg-derived elicitors. Our study brings molecular evidence for previous observations of oviposition-induced necrosis in other plant species and might illustrate a direct defense of the plant against the egg. In this addendum, we discuss the relevance of the oviposition-induced gene expression changes and the possibility that plants use eggs as cues to anticipate their enemies.

Air-Sea Battle -konsepti John Wardenin Enemy as a System -teorian näkökulmasta

Tutkielman tavoitteena oli analysoida Air-Sea Battle -konseptia ja sen lähtökohtana ollutta viholliskuvaa John Wardenin Enemy as a System -teorian näkökulmasta julkisten asiakirjojen, raporttien ja artikkeleiden avulla. Tutkimusmenetelmänä on käytetty teoriaohjaavaa sisällönanalyysia. Tutkimusongelmaksi muodostui: ”Miten Air-Sea Battle -konsepti näyttäytyy Wardenin Enemy as a System -teorian näkökulmasta?” Tutkimuskysymyksien avulla pyrittiin lisäksi löytämään konseptin kehittämiseen johtaneita tekijöitä suurstrategisella tasolla, arvioimaan konseptin mukaista aseellisen voiman käyttöä sekä analysoimaan konseptia suhteessa Wardenin näkemyksiin sotilasstrategiasta. Wardenin Enemy as a System -teoria on esitelty tutkielman alkupuolella hyödyntäen alkuperäistekstejä, aiheesta kirjoitettuja tutkimuksia ja artikkeleita sekä sotataidollista kirjallisuutta. Air-Sea Battle -konseptia käsittelevän luvun aineisto on luokiteltu Wardenin neljän strategisen kysymyksen teemojen, eli tavoitteen, vaikuttamisen kohteiden, keinojen ja irtautumisen, mukaisesti. Tärkeimmät lähteet varsinaisen Air-Sea Battle -asiakirjan lisäksi olivat Yhdysvaltojen turvallisuus- ja sotilasstrategiaa määrittelevät dokumentit, tutkimuslaitosten julkaisemat raportit sekä aikakauslehtiartikkelit. Aineiston perusteella Yhdysvallat näkee tiettyjen valtioiden, kuten Kiinan, kehittyvät niin kutsutut anti-access/area denial -suorituskyvyt uhkana alueelliselle tasapainolle ja heidän kyvylleen ylläpitää sotilaallista läsnäoloa strategisesti merkittävillä alueilla. Air-Sea le -konseptin tavoitteena on määritellä ja kehittää suorituskyvyt, operatiiviset suunnitelmat ja toimintamallit, joiden mukaan toimivalla joukolla kyetään luomaan riittävä pelotevaikutus konfliktin ehkäisemiseksi tai säilyttämään toiminnanvapaus alueella sen muodostuessa.

Report of the Committee to whom was referred so much of the message of the President of the United States, at the Commencement of the session, as relates to the spirit and manner in which the War has been waged by the enemy.--

July 31, 1813. Resolution agreed to and forwarded to the President.

Report of the Committee, as relates to the spirit and manner in which the War has been waged by the enemy

July 31, 1813. Resolution agreed to and forwarded to the President. Printed by A and G Way

Property Lost, Captured, or Destroyed by the Enemy 1812-14 (1824)

Government report in congress discussing property lost, captured, or destroyed by the British during the War of 1812.

Understanding biodiversity effects on prey in multi-enemy systems

Biodiversity-ecosystem functioning theory would predict that increasing natural enemy richness should enhance prey consumption rate due to functional complementarity of enemy species. However, several studies show that ecological interactions among natural enemies may result in complex effects of enemy diversity on prey consumption. Therefore, the challenge in understanding natural enemy diversity effects is to predict consumption rates of multiple enemies taking into account effects arising from patterns of prey use together with species interactions. Here, we show how complementary and redundant prey use patterns result in additive and saturating effects, respectively, and how ecological interactions such as phenotypic niche shifts, synergy and intraguild predation enlarge the range of outcomes to include null, synergistic and antagonistic effects. This study provides a simple theoretical framework that can be applied to experimental studies to infer the biological mechanisms underlying natural enemy diversity effects on prey.

Intra-specific variation affects the structure of the natural enemy assemblage attacking pea aphid colonies

1. Intra-specific variation in plant defence traits has been shown to profoundly affect herbivore community structure. Here we describe two experiments designed to test whether similar effects occur at higher trophic levels, by studying pea aphid–natural enemy interactions in a disused pasture in southern England. 2. In the first experiment, the numbers and identity of natural enemies attacking different monoclonal pea aphid colonies were recorded in a series of assays throughout the period of pea aphid activity. 3. In the summer assay, there was a significant effect of clone on the numbers of aphidophagous hoverfly larvae and the total number of non-hoverfly natural enemies recruited. Clone also appeared to influence the attack rate suffered by the primary predator in the system, the hoverfly Episyrphus balteatus, by Diplazon laetatorius, an ichneumonid parasitoid. Colonies were generally driven to extinction by hoverfly attack, resulting in the recording of low numbers of parasitoids and entomopathogens, suggesting intense intra-guild predation. 4. To further examine the influence of clonal variation on the recruitment of natural enemies, a second experiment was performed to monitor the temporal dynamics of community development. Colonies were destructively sampled every other day and the numbers of natural enemies attacking aphid colonies were recorded. These data demonstrated that clonal variation influenced the timing, abundance, and identity of natural enemies attacking aphid colonies. 5. Taken together, these data suggest that clonal variation may have a significant influence on the patterns of interactions between aphids and their natural enemies, and that such effects are likely to affect our understanding of the ecology and biological control of these insect herbivores.

The use of ultraviolet-blocking films in insect pest management in the UK; effects on naturally occurring arthropod pest and natural enemy populations in a protected cucumber crop

Studies in polytunnels were conducted to investigate the effects of ultraviolet (UV)-blocking films on naturally occurring insect pests and their arthropod natural enemies on a cucumber crop. Within tunnels clad with Antibotrytis (blocks light < 400 nm) and UVI/EVA (UV transmitting), 5.8 and 23.4 times more aphids, respectively, were recorded on traps compared with those on traps within tunnels clad with XL 385 (blocks light < 385 nm). When all plants within the UVI/EVA tunnels had become heavily infested with aphids, half of the plants in XL 385 tunnels were uninfested. More Coleoptera and thrips (approximately two times) were recorded under the UVI/EVA film than under the UV-blocking films, but for other arthropod pests (e. g. whitefly, leafhoppers), clear conclusions could not be drawn as low numbers were recorded. Substantial numbers of chalcid parasitoids and syrphids were found under the UV-blocking films, but further research is needed to evaluate fully the effect of such films on biological control of aphids. Higher syrphid numbers and more aphid mummies were recorded under the UVI/EVA film, probably because of the higher numbers of aphids present in tunnels clad with this film. The potential that UV-blocking films have as an effective component of commercial Integrated Pest Management (IPM) systems, for protected horticultural crops, is discussed.

Influence of temperature on pea aphid Acyrthosiphon pisum (Hemiptera: Aphididae) resistance to natural enemy attack

The ability to resist or avoid natural enemy attack is a critically important insect life history trait, yet little is understood of how these traits may be affected by temperature. This study investigated how different genotypes of the pea aphid Acyrthosiphon pisum Harris, a pest of leguminous crops, varied in resistance to three different natural enemies (a fungal pathogen, two species of parasitoid wasp and a coccinellid beetle), and whether expression of resistance was influenced by temperature. Substantial clonal variation in resistance to the three natural enemies was found. Temperature influenced the number of aphids succumbing to the fungal pathogen Erynia neoaphidis Remaudiere & Hermebert, with resistance increasing at higher temperatures (18 vs. 28degreesC). A temperature difference of 5degreesC (18 vs. 23degreesC) did not affect the ability of A. pisum to resist attack by the parasitoids Aphidius ervi Haliday and A. eadyi Stary Gonzalez & Hall. Escape behaviour from foraging coccinellid beetles (Hippodamia convergens Guerin-Meneville) was not directly influenced by aphid clone or temperature (16 vs. 21degreesC). However, there were significant interactions between clone and temperature (while most clones did not respond to temperature, one was less likely to escape at 16degreesC), and between aphid clone and ladybird presence (some clones showed greater changes in escape behaviour in response to the presence of foraging coccinellids than others). Therefore, while larger temperature differences may alter interactions between Acyrthosiphon pisum and an entomopathogen, there is little evidence to suggest that smaller changes in temperature will alter pea aphid-natural enemy interactions.