The citizen science project ‘Mückenatlas’: contributions of opportunistic data collection to mosquito research in Germany

Citizen science – the involvement of the public in scientific research – has become an emerging field, both as a research approach and as a discipline (the science of citizen science) by itself. The ‘Mückenatlas’ (German for ‘mosquito atlas’) was launched in 2012, shortly before citizen science also gained momentum in Germany. The goal of the ‘Mückenatlas’ is to support mapping the occurrence and distribution of native and introduced mosquito species. Therefore, people collect and submit physical mosquito samples to the responsible research institutions. In return, participants receive an individual answer with information about the biology of the captured spe¬cies and, if desired, a personal marker on the collectors’ map on the ‘Mückenatlas’ website. In this thesis, the project was evaluated from three perspectives, based on current controversies in citizen science: as a monitoring method, as a data source, and as a public outreach activity. The general aim of the dissertation was to assess the contributions of the opportunistic data collection of the ‘Mückenatlas’ project to mosquito research in Germany. The ‘Mückenatlas’ performance as monitoring method was evaluated by comparing it to a professional monitoring approach. The results showed that monitoring by professionals allows for a better coverage of land use types and species richness, whereas the citizen science approach provides important data from urban areas and can very well detect invasive species. By investigating the ‘Mückenatlas’ data collection as data source for research, anthropogenic and environmental factors were identified as drivers of the spatio-temporal variation in the numbers of submissions. Despite this bias, a study of the effects of urbanisation on indoor mosquito communities showed that opportunistic data have the capacity to confirm findings and generate novelty. Finally, considering the ‘Mückenatlas’ as an outreach activity demonstrated the positive association of mass media reports with the number of submissions across time and space. In addition, the style of the titles and texts of media reports, as well as an already raised media and public attention towards mosquito topics, increased the responsiveness of participants. The findings of this thesis show that the opportunistic data collection of the ‘Mückenatlas’ can make a crucial contribution to mosquito research, especially in gaining insights into species occurrence through the sheer number of samples submitted. Recommendations are made on when and how citizens can be involved in formal mosquito monitoring programmes, what biases and patterns to consider in data analysis, and how communication strategies can influence participation and affect the data

Citizen science as a bottom‐up approach to address human–wildlife conflicts: From theories and methods to practical implications

Although biodiversity conservation is a prioritized topic globally, agreements and regulations at multiple levels often fail to meet the desired effects due to insufficient knowledge transmission about and tolerance toward environmental protection measures among the public. To find effective measures to solve human-wildlife conflicts (HWCs) and promote a sustainable coexistence, it is essential to gain the public's understanding of the importance of preserving biodiversity. To spur progress in solution-oriented conservation science, we examine how citizen science (CS) can complement research in the HWC field and coexistence/mitigation strategies. We find that CS (1) is an effective tool for gathering wildlife data and (2) empowers citizens to participate in or drive (in a bottom-up manner) wildlife research and management. Each HWC has a unique social, economic, and geographical context, which makes it challenging to find appropriate mitigation measures. We developed a Global and Local Geographic (GLG) model that provides practical guidelines for implementing CS in HWC research. We argue that the inclusion of youth is fundamental to achieving coexistence between people and wildlife; thus integrating CS into formal education or including an educational component in CS projects can support the sustainable conservation of wildlife species and foster environmentally aware future generations

Buzzing Homes: Using Citizen Science Data to Explore the Effects of Urbanization on Indoor Mosquito Communities

Urbanization has been associated with a loss of overall biodiversity and a simultaneous increase in the abundance of a few species that thrive in urban habitats, such as highly adaptable mosquito vectors. To better understand how mosquito communities differ between levels of urbanization, we analyzed mosquito samples from inside private homes submitted to the citizen science project ‘Mückenatlas’. Applying two urbanization indicators based on soil sealing and human population density, we compared species composition and diversity at, and preferences towards, different urbanization levels. Species composition between groups of lowest and highest levels of urbanization differed significantly, which was presumably caused by reduced species richness and the dominance of synanthropic mosquito species in urban areas. The genus Anopheles was frequently submitted from areas with a low degree of urbanization, Aedes with a moderate degree, and Culex and Culiseta with a high degree of urbanization. Making use of citizen science data, this first study of indoor mosquito diversity in Germany demonstrated a simplification of communities with increasing urbanization. The dominance of vector-competent species in urban areas poses a potential risk of epidemics of mosquito-borne diseases that can only be contained by a permanent monitoring of mosquitoes and by acquiring a deeper knowledge about how anthropogenic activities affect vector ecology

Drivers of spatio-temporal variation in mosquito submissions to the citizen science project ‘Mückenatlas’

Intensified travel activities of humans and the ever growing global trade create opportunities of arthropod-borne disease agents and their vectors, such as mosquitoes, to establish in new regions. To update the knowledge of mosquito occurrence and distribution, a national mosquito monitoring programme was initiated in Germany in 2011, which has been complemented by a citizen science project, the ‘Mückenatlas’ since 2012. We analysed the ‘Mückenatlas’ dataset to (1) investigate causes of variation in submission numbers from the start of the project until 2017 and to (2) reveal biases induced by opportunistic data collection. Our results show that the temporal variation of submissions over the years is driven by fluctuating topicality of mosquito-borne diseases in the media and large-scale climate conditions. Hurdle models suggest a positive association of submission numbers with human population, catch location in the former political East Germany and the presence of water bodies, whereas precipitation and wind speed are negative predictors. We conclude that most anthropogenic and environmental effects on submission patterns are associated with the participants’ (recording) behaviour. Understanding how the citizen scientists’ behaviour shape opportunistic datasets help to take full advantage of the available information

Oviposition of Aedes japonicus japonicus (Diptera: Culicidae) and associated native species in relation to season, temperature and land use in western Germany

Background: Aedes japonicus japonicus, first detected in Europe in 2000 and considered established in Germany 10 years later, is of medical importance due to its opportunistic biting behaviour and its potential to transmit pathogenic viruses. Its seasonal phenology, temperature and land use preference related to oviposition in newly colonised regions remain unclear, especially in the context of co-occurring native mosquito species. Methods: Focussing on regions in Germany known to be infested by Ae. japonicus japonicus, we installed ovitraps in different landscapes and their transition zones and recorded the oviposition activity of mosquitoes in relation to season, temperature and land use (arable land, forest, settlement) in two field seasons (May-August 2017, April-November 2018). Results: Ae. japonicus japonicus eggs and larvae were encountered in 2017 from June to August and in 2018 from May to November, with a markedly high abundance from June to September in rural transition zones between forest and settlement, limited to water temperatures below 30 degrees C. Of the three native mosquito taxa using the ovitraps, the most frequent was Culex pipiens s.l., whose offspring was found in high numbers from June to August at water temperatures of up to 35 degrees C. The third recorded species, Anopheles plumbeus, rarely occurred in ovitraps positioned in settlements and on arable land, but was often associated with Ae. japonicus japonicus. The least frequent species, Aedes geniculatus, was mostly found in ovitraps located in the forest. Conclusions: The transition zone between forest and settlement was demonstrated to be the preferred oviposition habitat of Ae. japonicus japonicus, where it was also the most frequent container-inhabiting mosquito species in this study. Compared to native taxa, Ae. japonicus japonicus showed an extended seasonal activity period, presumably due to tolerance of colder water temperatures. Higher water temperatures and arable land represent distribution barriers to this species. The frequently co-occurring native species An. plumbeus might be useful as an indicator for potentially suitable oviposition habitats of Ae. japonicus japonicus in hitherto uncolonised regions. The results contribute to a better understanding of mosquito ecology and provide a basis for more targeted monitoring, distribution modelling and risk management of mosquitoes

How media presence triggers participation in citizen science—The case of the mosquito monitoring project ‘Mückenatlas‘

Since 2012, the citizen science project ‘Mückenatlas’ has been supplementing the German mosquito monitoring programme with over 28,000 submissions of physical insect samples. As the factors triggering people to catch mosquitoes for science are still unknown, we analysed the influence of mass media reports on mosquito submission numbers. Based on a theoretical framework of how mass media affect citizen responsiveness, we identified five possible influencing factors related to citizen science: (i) project awareness and knowledge, (ii) attention (economy), (iii) individual characteristics of citizen scientists and targeted communication, (iv) spatial differences and varying affectedness, and (v) media landscape. Hypotheses based on these influencing factors were quantitatively and qualitatively tested with two datasets: clipping data of mass media reports (online, television, radio and print) referring to or focussing on the ‘Mückenatlas’, and corresponding data of ‘Mückenatlas’ submissions between 2014 and 2017. In general, the number of media reports positively affected the number of mosquito submissions on a temporal and spatial scale, i.e. many media reports provoke many mosquito submissions. We found that an already heightened public and media awareness of mosquito-relevant topics combined with a direct call-to-action in a media report title led to a maximum participation. Differences on federal state level, however, suggest that factors additional to quantitative media coverage trigger participation in the ‘Mückenatlas’, in particular the mosquito affectedness of the resident population. Lastly, media types appear to differ in their effects on the number of submissions. Our results show under which circumstances the media presence of the ’Mückenatlas’ is most effective in activating people to submit mosquito samples, and thus provide advice for designing communication strategies for citizen science projects

Extracting secondary data from citizen science images reveals host flower preferences of the Mexican grass‐carrying wasp Isodontia mexicana in its native and introduced ranges

We investigated the plant-pollinator interactions of the Mexican grass-carrying wasp Isodontia mexicana—native to North America and introduced in Europe in the 1960s—through the use of secondary data from citizen science observations. We applied a novel data exchange workflow from two global citizen science platforms, iNaturalist and Pl@ntNet. Images from iNaturalist of the wasp were used to query the Pl@ntNet application to identify possible plant species present in the pictures. Simultaneously, botanists manually identified the plants at family, genus and species levels and additionally documented flower color and biotic interactions. The goals were to calibrate Pl@ntNet's accuracy in relation to this workflow, update the list of plant species that I. mexicana visits as well as its flower color preferences in its native and introduced ranges. In addition, we investigated the types and corresponding frequencies of other biotic interactions incidentally captured on the citizen scientists' images. Although the list of known host plants could be expanded, identifying the flora from images that predominantly show an insect proved difficult for both experts and the Pl@ntNet app. The workflow performs with a 75% probability of correct identification of the plant at the species level from a score of 0.8, and with over 90% chance of correct family and genus identification from a score of 0.5. Although the number of images above these scores may be limited due to the flower parts present on the pictures, our approach can help to get an overview into species interactions and generate more specific research questions. It could be used as a triaging method to select images for further investigation. Additionally, the manual analysis of the images has shown that the information they contain offers great potential for learning more about the ecology of an introduced species in its new range

Overcoming biodiversity blindness: Secondary data in primary citizen science observations

1. In the face of the global biodiversity crisis, collecting comprehensive data and making the best use of existing data are becoming increasingly important to understand patterns and drivers of environmental and biological phenomena at different scales. 2. Here we address the concept of secondary data, which refers to additional information unintentionally captured in species records, especially in multimedia-based citizen science reports. We argue that secondary data can provide a wealth of ecologically relevant information, the utilisation of which can enhance our understanding of traits and interactions among individual organisms, populations and biodiversity dynamics in general. 3. We explore the possibilities offered by secondary data and describe their main types and sources. An overview of research in this field provides a synthesis of the results already achieved using secondary data and different approaches to information extraction. 4. Finally, we discuss challenges to the widespread use of secondary data, such as biases, licensing issues, use of metadata and lack of awareness of this trove of data due to a missing common terminology, as well as possible solutions to overcome these barriers. 5. Although the exploration and use of secondary data is only emerging, the many opportunities identified show how these data can enrich biodiversity research and monitoring

Species interactions: next‐level citizen science

We envisage a future research environment where digital data on species interactions are easily accessible and comprehensively cover all species, life stages and habitats. To achieve this goal, we need data from many sources, including the largely untapped potential of citizen science for mobilising and utilising existing information on species interactions. Traditionally volunteers contributing information on the occurrence of species have focused on single-species observations from within one target taxon. We make recommendations on how to improve the gathering of species interaction data through citizen science, which data should be collected and how it can be motivated. These recommendations include providing feedback in the form of network visualisations, leveraging a wide variety of other data sources and eliciting an emotional connection to the species in question. There are many uses for these data, but in the context of biological invasions, information on species interactions will increase understanding of the effects of invasive alien species on recipient communities and ecosystems. We believe that the inclusion of ecological networks as a concept within citizen science, not only for initiatives focussed on biological invasions but also across other ecological themes, will not only enrich scientific knowledge on species interactions but also deepen the experience and enjoyment of citizens themselves

Citizen science versus professional data collection: Comparison of approaches to mosquito monitoring in Germany

Due to the recent emergence of invasive mosquito species and the outbreaks of mosquito-borne diseases in Europe, research on the ecology and diversity of the mosquito fauna has returned to scientific agendas. Through a nationwide surveillance programme in Germany, mosquitoes have been monitored actively by systematically operated traps since 2011, and passively by the 'Mückenatlas' (mosquito atlas) citizen science project launched in 2012. To assess the performance of both monitoring methods we compared the two respective datasets with regard to habitat coverage, species composition and the ability to detect invasive mosquitoes. The datasets include observations from the beginning of the project until the end of 2017. We found significant differences in species composition caused by land use types and the participants' recording activity. Active monitoring performed better in mapping mosquito diversity, whereas passive monitoring better detected invasive species, thereby using data from private premises scientists usually cannot access. Synthesis and applications. Active and passive monitoring is complementary. Combining them allows for the determination of mosquito diversity, efficient detection of emerging invasive species and the initiation of rapid-response actions against such invaders. The 'Mückenatlas' sets an example for the usefulness of citizen science when included in a national monitoring programme, an approach that may be worth copying for tackling the global spread of arthropod vectors of disease agents