New adhesive traps to monitor urban mosquitoes with a case study to assess the efficacy of insecticide control strategies in temperate areas

Background: Urban mosquitoes in temperate regions may represent a high nuisance and are associated with the risk of arbovirus transmission. Common practices to reduce this burden, at least in Italian highly infested urban areas, imply calendar-based larvicide treatments of street catch basins – which represent the main non-removable urban breeding site and/or insecticide ground spraying. The planning of these interventions, as well as the evaluation of their effectiveness, rarely benefit of adequate monitoring of the mosquito abundance and dynamics. We propose the use of adhesive traps to monitor Aedes albopictus and Culex pipiens adults and to evaluate the efficacy of insecticide-based control strategies. Methods: We designed two novel types of adhesive traps to collect adult mosquitoes visiting and/or emerging from catch basins. The Mosquito Emerging Trap (MET) was exploited to assess the efficacy of larvicide treatments. The Catch Basin Trap (CBT) was exploited together with the Sticky Trap (ST, commonly used to collect ovipositing/resting females) to monitor adults abundance in the campus of the University of Rome “Sapienza” - where catch basins were treated with Insect Growth Regulators (IGR) bi-monthly and Low-Volume insecticide spraying were carried out before sunset - and in a nearby control area. Results: Results obtained by MET showed that, although all monitored diflubenzuron-treated catch basins were repeatedly visited by Ae. albopictus and Cx. pipiens, adult emergence was inhibited in most basins. Results obtained by ST and CBT showed a significant lower adult abundance in the treated area than in the untreated one after the second adulticide spraying, which was carried out during the major phase of Ae. albopictus population expansion in Rome. Spatial heterogeneities in the effect of the treatments were also revealed. Conclusions: The results support the potential of the three adhesive traps tested in passively monitoring urban mosquito adult abundance and seasonal dynamics and in assessing the efficacy of control measures. ST showed higher specificity for Ae. albopictus and CBT for Cx. pipiens. The results also provide a preliminary indication on the effectiveness of common mosquito control strategies carried out against urban mosquito in European urban areas

ABUNDANCE AND DIVERSITY OF MACRO-MOTHS IN AN ACER-DOMINATEDFOREST OF THE POLLINO NATIONAL PARK, SOUTHERN ITALY(LEPIDOPTERA MACROHETEROCERA)

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NEW RECORDS OF MOTHS ELUCIDATE THE IMPORTANCE OF FORESTSAS BIODIVERSITY HOT-SPOTS IN CENTRAL MEDITERRANEAN LANDSCAPES(LEPIDOPTERA)

In this paper we report new faunistic findings concerning 15 moth species collected in forested habitats ofCalabria and Sicily regions, South Italy. Most interesting records concerned Eupithecia trisignariaand Orectisproboscidata,both recorded for the first time in southern Italy. Species with larval biology linked to the forest coverwere locally common, whilst species linked to herbaceous plants and shrubs were often collected as singletons or in onelocality, showing smaller populations. A study of a 658bp long sequence of the mitochondrial 5’ cytochrome oxidasegene, subunit 1 (COI) (barcoding analysis) was performed for five species, two of them showing a divergence fromclosest populations near to 1%, one a 2% divergence from northern populations, and two other species a perfect identitywith European populations. This study reinforced the role of forest habitats as biodiversity hot-spots in theMediterranean Basin and the importance of the Italian peninsula for biodiversity conservation at European scale as anincreased number of endemic or sub-endemic taxa and populations with endemic genetic lineages are recognized,underlining the existence of ongoing evolutionary processes. In the light of these results, faunistic surveys in forestecosystems are strongly needed to define sustainable management strategies

How different management regimes of chestnut forests affect diversity and abundance of moth communities?

Chestnut forests were exploited from centuries for several uses and are still nowadays managed under coppice and orchard regimes. The different management practices created a typical mosaic-like structure in landscapes in which alternate different kind of habitat represented by young and mature coppices, old thinned coppices with the physiognomy of high forest,  and managed or abandoned orchards. The aim of our study was to evaluate how the different kind of management could affect the hosted biodiversity. We used nocturnal Lepidoptera as indicators, sampled in different woodlots along an altitudinal gradient in the chestnut forests of the Catena Costiera Mountains, southern Italy. We analyzed a published dataset concerning 15 stands subjected to different management regimes. We found that the main variables affecting moth communities distribution were (i) the elevation at which the stands were located and (ii) the time elapsed from the last human intervention. In fact, the stands subjected to recent intervention (young coppices and managed orchards) showed low values of moth richness and abundance, on the contrary the stands subjected to old interventions (mature and old coppices and abandoned orchards) registered a high number of species and individuals, mainly due to their greater structural complexity. Despite the quantitative differences, in woodlots recently managed were collected exclusive species that increased the diversity at a landscape level. Our results underlined the importance to maintain a mosaic-like landscape taking into account also the altitude when interventions are planned in order to improve the ecological sustainability of chestnut forest exploitation

High Resolution Spatial Analysis of Habitat Preference of Aedes Albopictus (Diptera Culicidae) in an Urban Environment

Over the past decades, the Asian tiger mosquito (Aedes albopictus (Skuse, 1895)) has emerged in many countries, and it has colonized new environments, including urban areas. The species is a nuisance and a potential vector of several human pathogens, and a better understanding of the habitat preferences of the species is needed for help in successful prevention and control. So far, the habitat preference in urban environments has not been studied in Southern European cities. In this paper, spatial statistical models were used to evaluate the relationship between egg abundances and land cover types on the campus of Sapienza University in Rome, which is taken as an example of a European urban habitat. Predictor variables included land cover types, classified in detail on a high resolution image, as well as solar radiation and month of capture. The models account for repeated measures in the same trap and are adjusted for meteorological circumstances. Vegetation and solar radiation were found to be positively related to the number of eggs. More specifically, trees were positively related to the number of eggs and the relationship with grass was negative. These findings are consistent with the species' known preference for shaded areas. The unexpected positive relationship with solar radiation is amply discussed in the paper. This study represents a first step toward a better understanding of the spatial distribution of Ae. albopictus in urban environments

Overall mortality (%) in sentinel and control sites during the four experiments carried out in Rome.

<p>Experiment 1.1: 0,5% pyriproxyfen concentration; experiments 1.2, 2.1, 2.2: 5% pyriproxyfen concentration. Orange circles: sentinel sites numbered accordingly to <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001793#pntd-0001793-g002" target="_blank">Figures 2</a> and <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001793#pntd-0001793-g003" target="_blank">3</a>. Blue squares: control sites.</p

Ecology and results of “auto-dissemination” experiments in an enclosed garden in Rome (Italy).

<p>a and b – views of the study area with dissemination stations and sentinel and control sites; Exp. 2.1 and Exp. 2.2: frequencies (%) of dead <i>Aedes albopictus</i> larvae/pupae (in black) and of emerged adults (in white) in the first and second experiment carried out in the study area with 5% pyriproxyfen powder; sentinel sites are numbered accordingly to <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0001793#pntd-0001793-g004" target="_blank">Figure 4</a>.</p

Dissemination station (DS) used for “auto-dissemination” experiments in Rome.

<p>a – whole DS; b – higher and lower parts of DS, where arrow indicates black cotton cloth dusted with powdered pyriproxyfen; c – lower part of DS, where arrow indicates the net placed above the water level to prevent mosquitoes contacting with water.</p

<i>Aedes albopictus</i> mortality in control and sentinel sites during the experiments carried out in Rome.

<p>PPF = pyriproxyfen concentration; T = mean daily temperature during experiments; Total = percentage of dead larvae/pupae over 250 third instar larvae in 10 control sites (CS) and 10 sentinel (SS), respectively.</p