1,721,013 research outputs found
Problematiche entomologiche dell'eucalipto in Sardegna e monitoraggio del fitofago di nuova introduzione Psilla lerp (Glycaspis brimblecombei)
Full text linkFollowing the recent accidental introduction of the lerp psyllidGlycaspis brimblecombei(Moore) in Sardinia, entomological investigations on Eucalyptus were conducted during 2011-14. Field monitoring focused on the lerp psyllidG. brimblecombei(Moore), its specific parasitoidPsyllaephagus bliteus(Riek) and other phytophagous species like the Eucalyptus gall waspsOphelimus maskelli(Ashmead) andLeptocybe invasa(Fisher and La Salle), employing yellow sticky traps to collect adults, and foliar sampling to detect preimaginal and parasitized stages of the psyllid and to assess the number of wasp galls.G. brimblecombeiis currently the main pest of Eucalyptus in Sardinia where it reaches very high infestation levels (1070 adults/trap/month).P. bliteusdensity showed a bimodal trend, with the highest parasitism rates recorded in May (17%) and September (52%). The maximum number ofO. maskelliigalls per leaf were detected in April (78) while the minimum in July (7). In the case ofL. invasa, instead, the greatest percentage of affected leaves per branch was recorded in September (17%) while the lowest in July (3%).Among other phytophagous species,Blastopsylla occidentalis,Polydrusus (Metallites) parallelus,Gonipterussp., andPhoracanthaspp. were also detected.In addition, the impact of the red gum psyllid on the honey production during the flowering period (June-July) in 2014, was evaluated in preliminary observations including also other wild pollinators
INSECT PESTS OF EUCALYPTUSPLANTATIONS IN SARDINIA (ITALY)
Full text linkIn Sardinia (Italy), Eucalyptusplantations cover approximately 23,000 hectares, above all in the southern part ofthe island. There is a complex of phytophagous insect pests that is threatening the health status of Eucalyptustrees. Themost recent invasions include the sap-suckers, Glycaspis brimblecombei, Blastopsylla occidentalis, and the bronze bug,Thaumastocoris peregrinus. Other pest species have also been reported, including the gall wasps, Ophelimus maskelliand Leptocybe invasa, the longhorn beetles, Phoracantha semipunctataand P. recurva, and the weevils, Gonipterusscutellatusand Polydrusus(= Metallites) parallelus. Defoliation caused by the gypsy moth, Lymantria dispar, have alsobeen frequently observed in various Eucalyptus-planted areas of Sardinia
Nuovi fitofagi degli eucalipti e impatto sulla produzione mellifera in Sardegna
No full textGli eucalipti sono un genere di piante sempreverdi originarie dell’Oceania e appartenenti alla famiglia delleMyrtacee. Per il loro elevato potenziale nettarifero e pollinifero, costituiscono una delle più importanti risorse di interesse apistico in ambito mediterraneo e a livello mondiale. In particolare, la specieE. camaldulensis, introdotta in Sardegna agli inizi del secolo scorso, caratterizza ormai alcuni paesaggi agricoli delle zone costiere e di pianura, dove è stato utilizzato originariamente come frangivento e per le opere di bonifica
idraulica delle zone paludose. La superficie complessiva attualmente, non considerando i filari e gli impianti inferiori all’ettaro, ammonta a circa 22.000 ha. A partire dal 1969 sono stati segnalati i primi fitofagi (Phoracanthaspp. (Coleoptera: Cerambycidae)) senza
particolari ripercussioni negative. In anni recenti (2010-2015) il quadro fitosanitario si è notevolmente aggravato con l’introduzione e la diffusione dei rincotiGlycaspis brimblecombeieThaumastocoris peregrinus. Nel corso del 2013-2015, le popolazioni di
tali fitomizi sono state monitorate, soprattutto in seguito all’allarme lanciato dagli apicoltori per il mancato o ridotto ottenimento del miele di eucalipto, che rappresenta circa il 50% dell’intera produzione regionale. L’indagine è stata condotta su tutto il territorio regionale, in 12 siti di campionamento
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Agonistic interactions between the honeybee (<i>Apis mellifera ligustica</i>) and the European wasp (<i>Vespula germanica</i>) reveal context-dependent defense strategies
No full textPredator–prey relationships between sympatric species allow the evolution of defense behaviors, such as honeybee colonies defending their nests against predatory wasps. We investigated the predator–prey relationship between the honeybee (Apis mellifera ligustica) and the European wasp (Vespula germanica) by evaluating the effectiveness of attack and defense behaviors, which have coevolved in these sympatric species, as well as the actual damage and disturbance caused to the colonies under attack. Attack and defense behaviors were recorded in front of the hive to observe attacks at the hive entrance (68 attacks in 279 h) and at ground level on isolated and weakened honeybees close to the hive (465 attacks in 32 h). We found that V. germanica attacked the hive entrance infrequently due to the low success rate of this strategy and instead preferred a specialized attack method targeting adult honeybees at ground level, demonstrating opportunistic scavenger behavior. Individual honeybees usually responded effectively to an attack by recruiting an average of two nestmates, causing the wasp to flee, whereas collective balling behavior was only observed on four occasions. V. germanica does not appear to disrupt the foraging activity of the colonies under attack. We found that agonistic events supported by other nestmates were typically the most intense ones, involving physical combat and prolonged attacks at the entrance to the hive. These observations support the hypothesis that A. mellifera ligustica can adapt its behavior to match the severity of the threat and the context of the attack
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
A mediterranean silvo-pastoral system supporting beehive health and productivity
No full textThe biological, productive and sanitary conditions were investigated in an experimental apiary in order to evaluate the aptitude of the Mediterranean silvo-pastoral systems to the maintenance and exploitation of bee colonies through the best hive management practices. Observations on bee colony dynamics, honey production in storing supers, Paenibacillus larvae (White 1906) spores detection and Varroa destructor Anderson et Trueman infestation were conducted. The annual trend of bee population dynamics showed two typical peaks (spring and autumn). The total average honey production was 70 kg per hive. From a sanitary point of view, colonies looked normal and healthy with the sole exception of V. destructor infestations that were regularly kept under the intervention threshold by hive management operations. The results suggest that the Mediterranean agro-silvo-pastoral systems may be particularly suitable for productive and healthy apiculture
Quantitative variation in the core bacterial community associated with honey bees from Varroa-infested colonies
Full text linkInfestations of the ectoparasitic mite Varroa destructor cause significant honey bee colony weakening, due to both host-feeding and virus transmission effects. In addition to the natural (i.e., behavioral) and innate (i.e., cellular and humoral response) mechanisms of defense against pathogens and parasites, contribution to maintain good colony health may derive from the resident microbial community. The present study investigated variation in immune-related gene expression levels and in the relative abundance of representative bacterial taxa of the core honey bee microbiota in colonies infested by Varroa mites in comparison with honey bees from non-infested colonies. Significant changes in the target bacterial taxa (Gammaproteobacteria, Betaproteobacteria, Lactobacillus spp., Bifidobacterium spp., Brevibacillus laterosporus) were detected in immune-suppressed adults emerging from Varroa-infested colonies. Insect stages randomly sampled from infested and non-infested hives were characterized by high variability. Emerging adults bearing sucking Varroa mites on their body showed a considerably higher deformed wing virus titer and a greater immune gene downregulation compared with adults without mites. Further, the abundance of the overall bacterial community and of specific bacterial taxa increased significantly in parasitized adults. A possible compensation mechanism involving the core bacterial community in Varroa-infested hives is discussed
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