Ellen Kiel

Monitoring of putative vectors of bluetongue virus serotype 8, Germany.

To identify the vectors of bluetongue virus (BTV) in Germany, we monitored Culicoides spp. biting midges during April 2007–May 2008. Molecular characterization of batches of midges that tested positive for BTV suggests C. obsoletus sensu stricto as a relevant vector of bluetongue disease in central Europe.

Repeated introduction of Aedes albopictus into Germany, July to October 2012

During a small-scale surveillance project to identify possible routes of entry for invasive mosquitoes into Germany, 14 adult Aedes (Stegomyia) albopictus (Skuse) were discovered between July and October 2012. They were trapped at three different service stations in Bavaria and Baden-Wuerttemberg located along two motorways that connect Germany with southern Europe. This indicates regular introduction of A. albopictus into Germany and highlights the need for a continuous surveillance and control programme.

Field evaluation of four widely used mosquito traps in Central Europe.

BackgroundTo monitor adult mosquitoes several trapping devices are available. These are differently constructed and use various mechanisms for mosquito attraction, thus resulting in different trapping sensitivities and efficacies for the various species. Mosquito monitoring and surveillance programs in Europe use various types of mosquito traps, but only a few comparisons have been conducted so far. This study compared the performance of four commercial trapping devices, which are commonly used in Europe.MethodsFour different traps, Biogents Sentinel trap (BG trap), Heavy Duty Encephalitis Vector Survey trap (EVS trap), Centres for Disease Control miniature light trap (CDC trap) and Mosquito Magnet Patriot Mosquito trap (MM trap) were compared in a 4 × 4 latin square study. In the years 2012 and 2013, more than seventy 24-hour trap comparisons were conducted at ten different locations in northern and southern Germany, representing urban, forest and floodplain biotopes.ResultsPer 24-hour trapping period, the BG trap caught the widest range of mosquito species, the highest number of individuals of the genus Culex as well as the highest number of individuals of the species Ochlerotatus cantans, Aedes cinereus/geminus, Oc. communis and Culex pipiens/torrentium. The CDC trap revealed best performance for Aedes vexans, whereas the MM trap was most efficient for mosquitoes of the genus Anopheles and the species Oc. geniculatus. The EVS trap did not catch more individuals of any genus or species compared to the other three trapping devices. The BG trap caught the highest number of individuals per trapping period in urban environments as well as in wet forest, while the CDC trap caught the highest number of individuals in the floodplain biotopes. Additionally, the BG trap was most efficient for the number of mosquito species in urban locations.ConclusionThe BG trap showed a significantly better or similar performance compared to the CDC, EVS or MM trap with regard to trapping efficacy for most common mosquito species in Germany, including diversity of mosquito species and number of mosquitoes per trapping period. Thus, the BG trap is probably the best solution for general monitoring or surveillance programs of adult mosquitoes in Central Europe.

Monitoring of Culicoides at 20 locations in northwest Germany

Entomological monitoring was carried out from April 2007 to May 2008 at 20 locations in the areas of Lower Saxony, Schleswig-Holstein, Hamburg, and Bremen. A total number of 26 Culicoides species were sampled by light traps during the first week of every month. Culicoides diversity was highest in summer, achieving more than 20 species and genera per month. Numbers of Culicoides were highest in spring and summer with a maximum of 325,000 individuals in May 2008 at a single location. During the winter, the number of individuals decreased considerably, but few individuals of Culicoides were present even during the coldest months in January and February with Culicoides obsoletus remaining the only species complex. The total number of Ceratopogonidae and the number of individuals from C. obsoletus complex and Culicoides pulicaris complex were significantly correlated with temperature almost at any date and location.

The indication of morphological degradation of streams and rivers using Simuliidae

Abstract Blackfly communities from five German stream types out of two ecoregions (small and mid-sized siliceous gravel-bed mountain streams of the Central mountains, ecoregion 9, and organic type brooks, small and mid-sized sand-bottomed Central lowland streams of ecoregion 14) are compared. Ecoregional, as well as stream type-specific biocoenotic differences are discussed. The presence of Prosimulium sp. was restricted to mountain streams, whereas Simulium lineatum seemed to prefer mid-sized sand-bottomed Central lowland streams, and S. vernum showed a clear preference for Central lowland streams. An Index of Morphological Stress (IMS), derived from 22 geo-hydromorphological parameters recorded during sampling in the field, is presented. According to the IMS values, sites are divided into morphologically ‘unstressed’ sites (high or good morphological quality) and ‘stressed’ sites (moderate, poor or bad morphological quality), and biocoenotic differences of the two categories are discussed. Two stream types and the entire data set showed significantly higher numbers of taxa at ‘unstressed’ sites. Linear Multiple Regression (LMR) was used to identify geo-hydromorphological parameters that significantly explain the variance of the three most constant taxa, Prosimulium sp., P. hirtipes and Simulium sp. in the LMR model.

Review study on near-natural conditions of Central European mountain streams, with particular reference to debris and beaver dams: Results of the “REG meeting” 2000

Abstract This paper summarises the results of the “Rhithron Ecology Group” meeting in Essen (March 2000), supplemented by a literature evaluation. An extended view of small mountain streams in Central Europe under “potentially natural conditions” is presented. We focus on the potential impact of natural transverse structures (debris dams and beaver dams) on stream morphology, hydrology, habitat composition and communities. Furthermore, impact of other stream morphological features, which are presently lacking in the Central European landscape, is described. We suggest that Central European mountain streams are characterised by a higher proportion of lentic zones under “potentially natural conditions”. Morphological degradation leads to a loss of lentic zones and to an increase of current velocities and corresponding changes in faunal composition, particularly higher abundance and proportion of rheophilic species and a decrease of species preferring lentic zones. This should be regarded in future stream assessment.

Assessment of the abundance of Culicoides chiopterus and Culicoides dewulfi in bovine dung: A comparison of larvae extraction techniques and emergence traps

We compared two larvae extraction methods involving sugar-flotation and an adapted Berlese funnel-extraction with emergence traps. This was done in order to analyse the colonisation of cowpats by Culicoides chiopterus (Meigen 1830) and Culicoides dewulfi (Goetghebuer 1936) (Diptera: Ceratopogonidae) and to gain information on the comparability and efficacy of these three methods. With all three methods, a considerable number of individuals was obtained. Significantly more individuals were obtained via sugar-flotation and Berlese funnel-extraction compared to the emergence traps. These differences, likely due to natural mortality and sample processing are discussed. We recommend Berlese as an efficacious method for extracting Culicoides larvae from bovine dung. It produces data rapidly and extracted larvae are viable. In comparison with Berlese, slightly more larvae were obtained by sugar-flotation, but this method was very labour intensive.

Distribution of individual members of the mosquito Anopheles maculipennis complex in Germany identified by newly developed real‐time PCR assays

Owing to their role as vectors of malaria parasites, species of the Anopheles maculipennis complex (Diptera: Culicidae) Meigen were intensively studied in the past, but with the disappearance of malaria in Germany in the middle of the last century, the interest in this field of research declined. A comprehensive ecological analysis of the current species distribution for Germany is lacking.

Distance from the stable affects trapping of biting midges (Diptera, Ceratopogonidae)

Several species of Culicoides biting midges (Diptera, Ceratopogonidae) are competent vectors of important veterinary pathogens in Europe. Bluetongue virus (BTV) has emerged in Europe since the late 1990s and is transmitted by several species of the genus Culicoides (Caracappa et al. 2003, De Liberato et al. 2005). African horse sickness (AHS) was observed at the end of the last century on the Iberian Peninsula (Mellor and Hamblin 2004) and since the end of 2011 there has been evidence that biting midges are important vectors of the Schmallenberg Virus (SBV) emerging in Central Europe (Hoffmann et al. 2012). SBV causes considerable congenital damage, premature births, and reproductive disorders in ruminants. Monitoring programs for biting midges are generally based on UV-light/suction trap sampling (Mehlhorn et al. 2009, Nielsen et al. 2010). Results of the sampling and trapping protocols could be significantly affected by uncontrollable environmental factors like wind and temperature (Bishop et al. 2000, Carpenter et al. 2008) and/or even the phase of the moon (Bishop et al. 2000). In contrast, there are controllable factors that could be standardized and would result in more comparable results from entomological surveillance programs. Firstly, there is the standardization of the trapping method, which could have different specificity for abundance, taxa, sex, or feeding stadium (Holbrook 1985, Anderson and Linhares 1989, Venter et al. 2009a, Viennet et al. 2011). Secondly, some authors mentioned that the positions of the traps have a significant impact on the sampling results, such as height (Venter et al. 2009b) or habitat (Bishop et al. 1994, Bishop et al. 1995). In this study, we were interested in the impact of the distance to the stable on the trapping result. Due to a positive correlation between biting midge abundance and the presence and abundance of hosts (Bellis and Reid 1996, Baylis et al. 2010, Garcia-Saenz et al. 2011, Viennet et al. 2011), we expected a decreasing number of biting midges to occur in traps with increasing distance to the stable. The study was conducted between May and June, 2009 at one livestock farm that is surrounded by meadows in northern Germany. This site represents a typical dairy farm with 220 dairy cattle and is located in a typical agricultural region in the marshland of Lower Saxony. The grazing density of cattle was approximately 7.3 individuals per hectare, but the cattle were in the stables during the night. Sampling of Culicoides spp. was conducted with BGSentinelTM light traps fitted with ultraviolet light. Each of the three traps was placed in concentric circles in distances of 25, 50, 100, and 200 m (variable DISTANCE) around one trap in direct proximity to the stable (Figure 1a). All traps were installed at 1.5 m above the ground and operated with one car battery each per sampling period. A photo sensor was installed in the immediate vicinity of each trap. The photo sensor was adjusted to illuminate the ultraviolet light from sunset to dawn, because the activity of Culicoides spp. was expected to be highest in this time period (Kettle et al. 1998). The traps were sampled five times, every seventh day (variable SAMPLINGPERIOD). Insects were collected in 70% ethanol and stored in separate containers. The samples were presorted in order to separate biting midges from other insects and to differentiate members of the C. obsoletus and C. pulicaris group (also C. obsoletus or C. pulicaris in the subsequent text) from other Ceratopogonidae. All data analyses and graphs were made with the program R (R Development Core Team 2011). Due to overdispersion in the data, collection data of females of the Culicoides obsoletus and Culicoides pulicaris group were analyzed with negative binomial generalized linear models through the function glm. nb from the package MASS (Venables and Ripley 2002). The variables DISTANCE, DIRECTION, SAMPLINGPERIOD, and all interactions between the variables were implemented in the model. The value of the variable DIRECTION for each trap tr was calculated as:

Gelelectrophoretic studies on labial gland secretions of immature blackflies (Simuliidae, Diptera)

Abstract Any contact of blackfly larvae and pupae to the substrate they colonise relies on the adhesion of the secretion which is produced in their large labial glands. This secretion anchors their filter-feeding position, any locomotive activity, and the pupal cocoon as well. The secretion works as a biological adhesive which adheres to nearly any substrate surface — even to wood or the integument of other aquatic animals. We began analysing the proteinaceaous compounds of the labial gland secretions of Simulium ornatum (complex) Meigen . According to the SDS-PAGE and amino acid analyses, blackfly gland secretion consists of a variety of proteins ranging from high to low molecular weights. The most prominent proteins form broad bands at about 70, 40 and 20 kDa. These main proteins were present in secretions from young to old larvae as well as in pupal cocoon secretion, but their relative amounts change with larval development. Results of N-terminal sequencing of prominent proteins revealed no obvious homologies to protein sequences deposited in the databases up to now.