Seasonal Density Research Articles

Thrips-mediated impacts from transgenic rice expressing Cry1Ab on ecological fitness of non-target predator Orius tantilus (Hemiptera: Anthocoridae)

Various rice lines have been genetically modified with genes from Bacillus thuringiensis (Bt) to continuously produce Bt insecticidal proteins against lepidopteran larvae. The Bt insecticidal protein constantly expresses in the plants to create an opportunity for non-target herbivores to acquire and convey the protein to their predators or parasitoids across trophic levels. This paper evaluates the effects of Bt rice (namely, Kemindao 1 (KMD1) and Kemindao 2 (KMD2)) expressing Cry1Ab as compared to its non-Bt control line, Xiushui 11 on non-target predator Orius tantilus (a generalist predatory anthocorid of thrips) under laboratory and field conditions. To measure several biological parameters such as total nymphal duration and fecundity of this bug, it was reared on thrips and pollens of KMD1 and KMD2 as compared to their control under laboratory conditions. By comparison with the control, Bt rice did not significantly affect main life-history characteristics (total nymphal duration, female adult longevity, oviposition period and fecundity) of this anthocorid preying on Bt rice-fed thrips along with Bt rice pollens, except that the fecundity of this predator for KMD1 was distinctly lower as compared with KMD2 or the control. Enzyme-linked immunosorbent assay (ELISA) results showed that no Cry1Ab protein was detected in this predator fed on thrips or rice pollen from Bt rice but was in Bt rice pollens. With the beat plate, plastic bag and color trap sampling methods, two-year field monitoring of O. tantilus abundance demonstrated that Bt rice had no significant detrimental effects on the population dynamics and seasonal average densities of this predatory anthocorid as compared with the control. Thus, it is suggested that growing our tested Bt rice (KMD1 and KMD2) producing Cry1Ab will pose a negligible risk to the anthocorid, O. tantilus.

Population dynamics of the solitary ascidian Herdmania momus (Savignyi, 1816) in Jeju Island, Korea

In 2007–2008, a population outbreak of the solitary ascidian Herdmania momus was observed along the coasts of Jeju Island and the ascidians became the top dominant species in macrobenthic communities. We conducted field experiments on population dynamics and demographic parameters including seasonal density fluctuation, vertical distribution, recruitment patterns, mortality, and growth rate. Recruitment continued year-round except in April following the lowest water temperature season in February. Population density was highest in August-October, concomitantly with the peak in recruitment, related to the highest water temperature. The lowest density was observed in February-April when the water temperature was lowest. In April all individuals disappeared from all permanent plots, resulting in a maximum life span of 10–12 months. Individuals of newly recruited H. momus grew to have an adult size of 4–6 cm in only 3–4 months. Higher densities were observed in the shallower areas (5 m) compared to the deeper zones. More recruitment occurred on vertical slopes than horizontal substrates, but substrate pre-occupancy caused no difference in recruitment. This is the first report on H. momus population-level investigation in Korea, which provides valuable baseline information on the current status of population demography and their potential community-level influence on Jeju coasts.

Density and Climate Influence Seasonal Population Dynamics in an Arctic Ungulate

ABSTRACTThe locally migratory behavior of the high arctic muskox (Ovibos muschatus) is a central component of the breeding and winter survival strategies applied to cope with the highly seasonal arctic climate. However, altered climate regimes affecting plant growth are likely to affect local migration dynamics of the muskox. In this study, we apply long-term local-scale data on the seasonal distribution of muskoxen in the Zackenberg Valley, Northeast Greenland, to assess the degree of climatic influence on local seasonal muskox dynamics. Specifically, we analyze how seasonal climate (temperature, snow cover), forage availability (length of growth season), and the number of adult females available per male (operational sex ratio) influence changes in the seasonal density dependence, abundance, and immigration rate of muskoxen into the valley.The results suggested summer temperature as the major controlling factor in the seasonal, local-scale migration of muskoxen at Zackenberg. Specifically, higher summer temperatures, defined as the cumulative average daily positive degrees in June, July, and August, resulted in decreased density dependence and, consequently, increase in the seasonal abundance of muskox in the valley. Additionally, a longer growth season was found to increase the seasonal abundance of muskox in the Zackenberg Valley. In contrast, changes in spring snow cover displayed no direct relation to the seasonal immigration rate. Our study suggests that access to high-quality forage is important for the short-term, local scale population dynamics of muskoxen in Northeast Greenland.

Luminescence and density banding patterns in massive Porites corals around the Thai-Malay Peninsula, Southeast Asia

We characterized the annual luminescent and skeletal density banding patterns in 51 massive Porites corals from 15 reefs from six locations around the Thai-Malay Peninsula in Southeast Asia, and explored the seasonal environmental cues/drivers of band formation. Location-specific recurrent annual luminescent banding patterns were found at all study locations with a brighter band occurring toward the end of the year (∼October/November/December) (at five locations) and in ∼June (one location). Annual density banding patterns could only be discerned at four locations, and were categorized into those that formed a dense band commencing ∼November/December, and those starting ∼May/June. Overall, compared to luminescence, variations in skeletal density provided a less clear signal for demarcation of annual growth increments. Seasonal variations in luminescence showed clearest relationships with salinity, as a proxy for freshwater/river runoff. No convincing relationship between intra-annual luminescence intensity and density variations was found, which supports the notion that luminescent banding is due to inclusions of fluorophores into the coral skeleton rather than variations in skeletal architecture. The relationships between seasonal density variations and significant wave height and rainfall suggest density banding in this region is likely related to wave energy, or some other correlated environmental parameter/s. The large variability in skeletal banding patterns not only highlights the current relatively poor understanding of their nature and causes, but also the need for replication in their interpretation, especially in settings with complex seasonal hydrodynamic/hydrological patterns such as those found around the Thai-Malay Peninsula.

Unusual behavior of the low‐latitude ionosphere in the Indian sector during the deep solar minimum in 2009

AbstractIn this paper we carry out a comparative study of the daytime (7–18 LT) behavior of the near‐equatorial ionospheric F region at the end of the long deep solar minimum (2009) with respect to that of the previous normal solar minimum (1995) in the Indian longitude sector using ionosonde observations of F layer parameters, radar observations of E × B drift, and the IRI‐2012 (International Reference Ionosphere‐2012) model. We investigate the F2 and F3 layer behaviors separately. The results reveal that the peak frequencies of the F layer (fpeak), F2 layer (foF2), and F3 layer (foF3) in 2009 are consistently lower than those in 1995. Maximum difference in fpeak/foF2/foF3 between 2009 and 1995 observations is found in the equinoxes followed by winter and summer. The annual mean, seasonal mean, and 10 day mean peak electron density (corresponding to fpeak) in 2009 were lower than those in 1995 by as much as 34%, 46%, and 65%, respectively. Solar rotation effect is less conspicuous in 2009 than in 1995, consistent with the solar rotation signature in F10.7. Observations also show considerable amount of equinoctial asymmetry in electron density, which is found to be closely linked with the corresponding asymmetry in the vertical E × B drift. Seasonal mean peak electron densities of the F layer (corresponding to fpeak) and the F2 layer (corresponding to foF2) observed during the deep solar minimum of 2009 were smaller than those corresponding to IRI‐2012 model foF2 by as much as 45% and 50%, respectively, underlining the need to incorporate the data collected during the long deep minimum in the IRI model. The unusually weak ionosphere observed in 2009 is discussed in terms of the direct effect of the low solar EUV flux in 2009 as compared to 1995 and its indirect effects on ionospheric electric field, thermospheric composition (or O/N2 ratio), and thermospheric neutral winds.

Seasonal Differences in Density But Similar Competitive Impact of Aedes albopictus (Skuse) on Aedes aegypti (L.) in Rio de Janeiro, Brazil.

Previous studies have shown that the negative effects of density of Ae. albopictus on Ae. aegypti exceed those of Ae. aegypti on Ae. albopictus for population growth, adult size, survivorship, and developmental rate. This competitive superiority has been invoked to explain the displacement of Ae. aegypti by Ae. albopictus in the southeastern USA. In Brazil, these species coexist in many vegetated suburban and rural areas. We investigated a related, but less-well-studied question: do effects of Ae. albopictus on Ae. aegypti larval development and survival occur under field conditions at realistic densities across multiple seasons in Brazil? We conducted additive competition experiments in a vegetated area of Rio de Janeiro where these species coexist. We tested the hypothesis that Ae. aegypti (the focal species, at a fixed density) suffers negative effects on development and survivorship across a gradient of increasing densities of Ae. albopictus (the associate species) in three seasons. The results showed statistically significant effects of both season and larval density on Ae. aegypti survivorship, and significant effects of season on development rate, with no significant season-density interactions. Densities of Aedes larvae in these habitats differed among seasons by a factor of up to 7x. Overall, Spring was the most favorable season for Ae. aegypti survivorship and development. Results showed that under natural conditions the negative competitive effects of Ae. albopictus on Ae. aegypti were expressed primarily as lower survivorship. Coexistence between Ae. aegypti and Ae. albopictus in vegetated areas is likely affected by seasonal environmental differences, such as detrital resource levels or egg desiccation, which can influence competition between these species. Interactions between these Aedes are important in Brazil, where both species are well established and widely distributed and vector dengue, Zika and chikungunya viruses.

Protective effect of organic substrates against soil-borne pathogens in soilless cucumber crops

The development of sustainable crop protection is expected by vegetable producers and highly encouraged by authorities. For crops grown in soilless systems, vegetable fibers are relevant for both agronomical and plant protection purposes. This work examines their potential against the soil-borne pathogen Fusarium oxysporum f. sp. radicis-cucumerinum.Wood fiber, coir fiber and peat were tested over two cucumber cropping periods. Fusarium blight symptoms were monitored on cucumber, and fungal community structure (PCR-TTGE) in substrates. Substrate sterilization and bio-augmentation with antagonistic strains were also studied; they did not modify protection. Compared to the other substrates, wood fiber increased protection at the end of the first assay, but did not during the second assay. Differences in crop season and plant density may have impacted on cucumber physiology and may have indirectly modified rhizosphere fungal community structure.The sole determination of microbial activity in substrates is not sufficient to predict protection. Growth conditions, substrate type and the microbiome altogether impacted on the protection of cucumber.

Fate of pharmaceutical micro-pollutants in Lake Tegel (Berlin, Germany): the impact of lake-specific mechanisms

Pharmaceuticals in the aquatic environment have become important because of the risk of harmful effects to ecosystem and drinking water abstraction. This is also the case in shallow dimictic Lake Tegel, located in the city area of Berlin, Germany. Here, drinking water is produced via bank filtration and artificial groundwater recharge, and concurrently, a substantial anthropogenic load takes place by micro-pollutants from a municipal wastewater treatment plant. The measured mean daily loads of 260 g d−1 carbamazepine, 180 g d−1 diclofenac and 60 g d−1 sulfamethoxazole results in the highest so far reported concentrations from natural waters, which are used as a drinking water resource. In the present study the spatial horizontal and vertical distribution and elimination of these three pharmaceuticals are quantified with the help of high-resolution sampling in Lake Tegel and its entire major in- and outflows. Monthly mass balances are modelled and substance-specific zero-order elimination rates are derived. Diclofenac showed the strongest elimination and revealed a significant seasonality with 50 % elimination in winter, and 95 % in summer. Elimination of carbamazepine was about 40 %; sulfamethoxazole did not degrade at determinable rates. Based on a basic plug-flow approach, a pseudo first-order elimination rate for diclofenac in summer (0.058 d−1, half-life 12 days) was calculated from horizontal concentration gradient. Apart from presenting the current state of pharmaceuticals pollution in Lake Tegel, results demonstrate the importance of lake-specific mechanisms, such as inflow–outflow balances and seasonal density stratification for the transport of micro-pollutants.

Local artifacts in ice core methane records caused by layered bubble trapping and in situ production: a multi-site investigation

Abstract. Advances in trace gas analysis allow localised, non-atmospheric features to be resolved in ice cores, superimposed on the coherent atmospheric signal. These high-frequency signals could not have survived the low-pass filter effect that gas diffusion in the firn exerts on the atmospheric history and therefore do not result from changes in the atmospheric composition at the ice sheet surface. Using continuous methane (CH4) records obtained from five polar ice cores, we characterise these non-atmospheric signals and explore their origin. Isolated samples, enriched in CH4 in the Tunu13 (Greenland) record are linked to the presence of melt layers. Melting can enrich the methane concentration due to a solubility effect, but we find that an additional in situ process is required to generate the full magnitude of these anomalies. Furthermore, in all the ice cores studied there is evidence of reproducible, decimetre-scale CH4 variability. Through a series of tests, we demonstrate that this is an artifact of layered bubble trapping in a heterogeneous-density firn column; we use the term “trapping signal” for this phenomenon. The peak-to-peak amplitude of the trapping signal is typically 5 ppb, but may exceed 40 ppb. Signal magnitude increases with atmospheric CH4 growth rate and seasonal density contrast, and decreases with accumulation rate. Significant annual periodicity is present in the CH4 variability of two Greenland ice cores, suggesting that layered gas trapping at these sites is controlled by regular, seasonal variations in the physical properties of the firn. Future analytical campaigns should anticipate high-frequency artifacts at high-melt ice core sites or during time periods with high atmospheric CH4 growth rate in order to avoid misinterpretation of such features as past changes in atmospheric composition.

Comparison of Peach Cultivars for Provision of Extrafloral Nectar Resources to Harmonia axyridis (Coleoptera: Coccinellidae).

Incorporating nonprey sugar resources into apple orchards is a potential means of enhancing biological control services, but little is known about the impacts of extrafloral nectars on aphidophagous coccinellids. We explored peach Prunus persica (L.) Batsch extrafloral nectar as a supplemental resource for Harmonia axyridis (Pallas), a key aphid predator in the mid-Atlantic United States. Extrafloral nectar quantity, temporal production, and carbohydrate profile were assessed for four peach cultivars in orchard and greenhouse culture. Seasonal densities of H. axyridis visiting extrafloral nectaries were estimated, and the propensity of beetles to feed upon extrafloral nectar was compared by cultivar in the laboratory. We also compared survival of newly eclosed adult pairs that were starved or fed aphids with or without extrafloral nectar. Peach extrafloral nectar contained six carbohydrates, with sucrose dominant for all cultivars, but extrafloral nectar production varied significantly by cultivar and collection date, with 'Lovell' yielding higher average seasonal volume than the other cultivars. Harmonia axyridis continuously foraged on peach trees lacking prey, and beetle abundance was positively correlated with the number of leaves actively producing extrafloral nectar. In laboratory assays, newly emerged adult beetles preferentially selected and consumed extrafloral nectar of Lovell peach shoots. Furthermore, when prey were initially unavailable to adult H. axyridis, the beetles were sustained by extrafloral nectar and experienced longer survival compared with beetles without the supplemental resource. Collectively, these results suggest that peach extrafloral nectar is a beneficial resource that could potentially sustain H. axyridis in orchards when prey are scarce.

Effect of human use, season and habitat on ungulate density in Kanha Tiger Reserve, Madhya Pradesh, India

Conservation practitioners require strata specific, seasonal species densities for habitat management. Herein, we use stratified distance sampling in Kanha Tiger Reserve (KTR) with 200 spatial transects and an effort of 1200 km walk in the year 2013. Analysis was done to access (a) impact of human use and (b) effect of habitat and season on ungulate densities in KTR. While a single detection function for each species was used for estimating density within human-restricted core and multiple use buffer of KTR, species-specific seasonal detections were modelled for each habitat. Ungulate biomass was 4.8 times higher in the core area compared with the buffer zone. The core supported a herbivore density and biomass of 50 ± 4.80/km2 and 26,806 ± 2573 kg/km2, respectively. Chital were found to be most abundant, having a density of 30.1 ± 4.34/km2 and contributing 33 % of the biomass with a habitat preference for grasslands (106 ± 39/km2) in summer and winter. Sambar had highest density (15.4 ± 3.34/km2) in bamboo-mixed habitat, in both seasons. Gaur contributed 39 % of the ungulate biomass and showed a seasonal shift in density from sal forests (9.65 ± 3.55/km2) in summer to miscellaneous forests (8.13 ± 1.94/km2) in winter. Barasingha were restricted to grasslands with similar summer and winter densities of 1.56 ± 0.76/km2. Chousingha were rare (0.1 ± 0.04/km2), found mostly in miscellaneous forests and plateau grasslands. Grassland and bamboo-mixed forests supported 58 % of the total ungulate biomass. Management for an optimal habitat mosaic that maintains ungulate diversity, addresses the specific needs of endangered species and maximizes ungulate biomass is recommended.

Wolf visitations close to human residences in Finland: The role of age, residence density, and time of day

Large carnivorous mammals, such as the gray wolf (Canis lupus) have been recently expanding to human-dominated landscapes in many regions. Although wolves tend to avoid human infrastructure, visitations close to human residences might be unavoidable in territories that are highly fragmented by residential areas. House yard visits are of particular concern: according to the Finnish legislation, wolves that repeatedly approach within 150m from the nearest residential building can legally be killed for human safety. We analyzed the average distance from house yards and probability of house yard visitations by wolves against sex, age class, time of the day, season and house density for 25 territorial GPS-tracked wolves in Finland. Generally, wolves avoid houses — with mean distances higher than from random locations in the territory. This difference became higher with decreasing house density for sub-adults while for adults this difference decreased slightly with decreasing house density. Probability of visitation in house-yards increased with increasing house densities, was far higher at night than in the daytime, a difference that was greater with increasing house density. Sub-adults visited house-yards more often than adult wolves in the first summer after spring dispersal from the natal pack to a territory, but there was no difference in winter. The indication that wolves learn within a season to avoid moving to near residential buildings in human-dominated territories is when the territory becomes more familiar to wolves which is a noteworthy result for the management.

Annual variation of phytoplankton communities and its driving environmental factors in a subtropical mussel-fish integrated pond in China

In this study, phytoplankton communities as well as environmental factors in a subtropical mussel-fish integrated pond in China were investigated during December 2012 to November 2013. Phytoplankton showed distinct seasonal density shifts in community structure at both taxonomic and functional levels. Cryptophyta was the dominant assemblage in low and moderate temperature, especially in January, April and May. Cryptophyta was gradually replaced by Cyanophyta with increase in temperature and formed cyanobacterial bloom in July. Chlorophyta became the most dominant group in the following six months with the second dominant assemblages of Cyanophyta, Cryptophyta and Bacillariophyta every two months in turn. Bacillariophyta was the dominant assemblage in March with low temperature and nutrients concentration. It appeared that water temperature and total nitrogen (TN) were the most critical factors driving phytoplankton community shift in terms of density and biomass, respectively.

Habitat Preferences of the Grey Parrot in Heterogeneous Vegetation Landscapes and Their Conservation Implications

The wild Grey ParrotPsittacus erithacusLinnaeus suffers from many habitat use challenges in the wake of extensive deforestation in its endemic range of West and Central African rainforests. To determine effects of these challenges on the bird species, seasonal densities of the Grey Parrot were determined using line transects in major heterogeneous vegetation types in the Korup Rainforest, south-western Cameroon. Results of the study highlight habitat preferences of this species on a seasonal base and under different situations of human activity intensity in the landscape. This information can be used to understand the causes of changes in the distribution and abundance of endangered species and also to determine sustainable conservation strategies. It is concluded that the parrot needs diverse vegetation types for survival in the wild state, as it depends on specific tree species for specific habitat resources such as food, roosts, security, and nests at specific periods of the year. Hence, the continuous survival of the Grey Parrot in the range states is not certain, if sustainable measures are not taken to conserve the parrot and its habitat resources both in and outside protected areas.

Trends in seasonal population densities of wildlife species in Tarangire National Park, Tanzania

Trends in seasonal population densities of wildlife species in Tarangire National Park, Tanzania

Wildlife species richness and densities in wildlife corridors of Northern Tanzania

Wildlife corridors are crucial for effective conservation in fragmented landscapes, yet these corridors are vanishing across Africa. In order to assess the relative conservation effectiveness of two distinct management areas linking Tarangire and Lake Manyara National Parks in Northern Tanzania, we assessed seasonal densities of wild and domestic species as well as species richness of large mammals over a 3-plus-year time period. Line distance sampling showed that livestock densities were considerably higher in a human-dominated area with little enforcement of natural resource utilization (Mto wa Mbu Game Controlled Area; CA) than in a Maasai pastoral area with stricter limitations and enforcement of natural resource utilization (Manyara Ranch; MR). Conversely, densities of most corridor-dwelling (giraffe, Kirk’s dik dik, and ostrich) and migratory (Grant’s gazelles, zebra, and wildebeest) wildlife species were mostly higher in MR compared to the CA. Large mammal species richness was about two times higher in MR than in the CA. Despite strong anthropogenic pressures on communal lands and natural resources, our long-term wildlife monitoring provides evidence of continued connectivity in the Tarangire-Manyara ecosystem. At the same time, we caution that continued land-use changes and illegal exploitation of wildlife resources severely threaten the functional connectivity of this ecosystem. Our comparative analysis highlights the conservation value of pastoral lands in East African savannahs, provided that additional stressors such as land-use changes and uncontrolled hunting of wildlife are restricted.

Natural islands and habitat islands as refuges of vegetation cover and wild bees. The case of the Lednica Landscape Park in western Poland

Abstract The study has contributed to the identification of the apifauna of central Wielkopolska. The study identified 161 bee species, accounting for 34.2% of the Polish bee fauna. The highest contribution (28.7% of the fauna) comes from four species, namely Andrena haemorrhoa, A. helvola, Evylaeus calceatus and Osmia rufa, while Bombus terrestris and Evylaeus pauxillus are two subdominants. The assemblages of Apiformes in the study area are characterised by a significant contribution of spring-associated species, which is probably an effect of the presence of numerous willow thickets offering abundant host plants (mainly Salix sp. div.). Both the islands and the surroundings of the lake have a unique species composition, and there are differences in the proportions of the individual dominant species. The overall abundance of bees varies greatly, with mean seasonal density figures on Ostrów Lednicki Island being more than twice as high as that on the mainland grassland, with a distinct predominance of bumblebees. The exceptional richness of Apiformes, including bumblebees, on Ostrów Lednicki should be regarded as the basis for treating this island as a life refuge for bumblebees and including it and its environs in the list of sites of Community importance (SCI). A simultaneous study of the vegetation cover contributed significant data on the vascular plant flora and plant communities of the Lednica Landscape Park. For example, it was the first such investigation of Mewia Island. The study revealed the importance of marginal habitats (natural islands and habitat islands) for the preservation of protected and endangered plant species and plant communities receding from an agricultural landscape.

Historical Seasonal Density and Distribution Patterns of Tursiops truncatus in Northeast Florida

Historical Seasonal Density and Distribution Patterns of Tursiops truncatus in Northeast Florida

Effects of habitat and land use on breeding season density of male Asian Houbara Chlamydotis macqueenii

Landscape-scale habitat and land use influences on Asian Houbara Chlamydotis macqueenii (IUCN Vulnerable) remain unstudied, while estimating numbers of this cryptic, low-density, over-hunted species is challenging. In spring 2013, male houbara were recorded at 231 point counts, conducted twice, across a gradient of sheep density and shrub assemblages within 14,300 km2 of the Kyzylkum Desert, Uzbekistan. Four sets of models related male abundance to: (1) vegetation structure (shrub height and substrate); (2) shrub assemblage; (3) shrub species composition (multidimensional scaling); (4) remote-sensed derived land cover (GLOBCOVER, 4 variables). Each set also incorporated measures of landscape rugosity and sheep density. For each set, multi-model inference was applied to generalised linear mixed models of visit-specific counts that included important detectability covariates and point ID as random effects. Vegetation structure received strongest support, followed by shrub species composition and shrub assemblage, with weakest support for the GLOBCOVER model set. Male houbara numbers were greater with lower mean shrub height, more gravel and flatter surfaces, but were unaffected by sheep density. Male density (mean 0.14 km−2) estimated by distance analysis differed substantially among shrub assemblages, being highest in vegetation dominated by Salsola rigida, high in areas of S. arbuscula and Astragalus, respectively, lower in Artemisia and lowest in Calligonum. The study area was estimated to hold 1824 males (CI 1645–2030). The spatial distribution of relative male houbara abundance, predicted from vegetation structure models, had the strongest correspondence with observed numbers in both model calibration and the subsequent year’s data. We found no effect of pastoralism on male distribution, but potential effects on nesting females are unknown. Density differences among shrub communities suggest extrapolation to estimate country- or range-wide population size must take into account vegetation composition.

Seasonal Dynamics of Phlebotomine Sand Fly Species Proven Vectors of Mediterranean Leishmaniasis Caused by Leishmania infantum.

BackgroundThe recent geographical expansion of phlebotomine vectors of Leishmania infantum in the Mediterranean subregion has been attributed to ongoing climate changes. At these latitudes, the activity of sand flies is typically seasonal; because seasonal phenomena are also sensitive to general variations in climate, current phenological data sets can provide a baseline for continuing investigations on sand fly population dynamics that may impact on future scenarios of leishmaniasis transmission. With this aim, in 2011–2013 a consortium of partners from eight Mediterranean countries carried out entomological investigations in sites where L. infantum transmission was recently reported.Methods/Principal FindingsA common protocol for sand fly collection included monthly captures by CDC light traps, complemented by sticky traps in most of the sites. Collections were replicated for more than one season in order to reduce the effects of local weather events. In each site, the trapping effort was left unchanged throughout the survey to legitimate inter-seasonal comparisons. Data from 99,000 collected specimens were analyzed, resulting in the description of seasonal dynamics of 56,000 sand flies belonging to L. infantum vector species throughout a wide geographical area, namely P. perniciosus (Portugal, Spain and Italy), P. ariasi (France), P. neglectus (Greece), P. tobbi (Cyprus and Turkey), P. balcanicus and P. kandelakii (Georgia). Time of sand fly appearance/disappearance in collections differed between sites, and seasonal densities showed variations in each site. Significant correlations were found between latitude/mean annual temperature of sites and i) the first month of sand fly appearance, that ranged from early April to the first half of June; ii) the type of density trend, varying from a single peak in July/August to multiple peaks increasing in magnitude from May through September. A 3-modal trend, recorded for P. tobbi in Cyprus, represents a novel finding for a L. infantum vector. Adults ended the activity starting from mid September through November, without significant correlation with latitude/mean annual temperature of sites. The period of potential exposure to L.infantum in the Mediterranean subregion, as inferred by adult densities calculated from 3 years, 37 sites and 6 competent vector species, was associated to a regular bell-shaped density curve having a wide peak center encompassing the July-September period, and falling between early May to late October for more than 99% of values. Apparently no risk for leishmaniasis transmission took place from December through March in the years considered. We found a common pattern of nocturnal females activity, whose density peaked between 11 pm and 2 am.ConclusionsDespite annual variations, multiple collections performed over consecutive years provided homogeneous patterns of the potential behavior of leishmaniasis vectors in selected sites, which we propose may represent sentinel areas for future monitoring. In the investigated years, higher potential risk for L. infantum transmission in the Mediterranean was identified in the June-October period (97% relative vector density), however such risk was not equally distributed throughout the region, since density waves of adults occurred earlier and were more frequent in southern territories.