Snail shell colour evolution in urban heat islands detected via citizen science

Abstract

12The extreme environmental conditions that prevail in cities are known to cause selection pressures leading to 13 adaptive changes in wild, city--dwelling, organisms ("urban evolution"). The urban heat island, elevated 14 temperatures in the city centre due to a combination of generation, reflection, and trapping of heat, is one of the 15 best recognised and most widespread urban environmental factors. Here, we used a citizen--science approach to 16 study the effects of urban heat on genetically--determined shell colour in the land snail Cepaea nemoralis in the 17Netherlands. We used smartphone applications to obtain colour data on almost 8,000 snails throughout the 18 country. Our analysis shows that snails in urban centres are more likely to be yellow than pink, an effect predicted 19 on the basis of thermal selection. Urban yellow snails are also more likely to carry dark bands at the underside of 20 the shell; these bands might affect thermoregulation in yet underexplored ways. 21 22

Morph-dependent nematode infection and its association with host movement in the land snail Cepaea nemoralis (Mollusca, Gastropoda)

“…If confirmed, our results suggest that morph-dependent predation confers no additional trematode-avoiding advantage. In addition, snail morphs differ in their thermal responses: lighter-coloured morphs are better adapted to heat, and increase in frequency with global warming or urbanization (Jones et al ., 1977; Silvertown et al ., 2011; Ożgo et al ., 2017; Kerstes et al ., 2019). If lighter morphs are more vulnerable to infection by nematodes, then we need to understand how snail immunity will interact with thermal tolerances to jointly shape snail and nematode dynamics (El-Danasoury & Iglesias-Piñeiro, 2017; Aleuy & Kutz, 2020), especially given potential risks to public and veterinary health (Meerburg et al ., 2009; Giannelli et al ., 2016).…”

“…Jones et al, 1977; Silvertown et al, 2011; Ożgo et al, 2017;Kerstes et al, 2019). If lighter morphs are more vulnerable to infection by nematodes, then we need to understand how snail immunity will interact with thermal tolerances to jointly shape snail and nematode dynamics(El-Danasoury & Iglesias-Piñeiro, 2017;Aleuy & Kutz, 2020), especially given potential risks to public and veterinary health(Meerburg et al, 2009;Giannelli et al, 2016).Morelli, S., Traversa, D., Colombo, M., Raue, K., Strube, C., Pollmeier, M. & Di Cesare, A.…”

Qualitative and quantitative methods show stability in patterns of Cepaea nemoralis shell polymorphism in the Pyrenees over five decades

“…In the future, we anticipate that a model that takes the best of both methods may be used instead. Websites and apps such as SnailSnap, iNaturalist and iRecord (Harvey, 2018, Horn et al, 2018, Kerstes et al, 2019 are already being used extensively by the general public to capture records and images of snails, which are then identified using a combination of machine-learning methods and input from persons with various degrees of expertise. For example, iNaturalist has over 9000 observations, including photos, of C. nemoralis at "research grade" quality (including >1000 in the UK, but only 29 in the Pyrenean region).…”

“…Overall, while there are key benefits in taking quantitative measures of colour in the laboratory, there are also several practical disadvantages. In the future, with the increasing use of digital cameras to capture and record species presence, there is the potential that colour and banding data may be extracted from the images uploaded to public databases and apps such as iRecord, iNaturalist and SnailSnap (Harvey, 2018, Horn et al, 2018, Kerstes et al, 2019. For the moment, the fact remains that humanscoring of snail colour data is valuable, especially with appropriate training.…”

Citizen science via social media revealed conditions of symbiosis between a marine gastropod and an epibiotic alga

“…Some studies have also aimed to solve traditional problems in ecology by obtaining ecological data with the help of citizen science 16,24 . Developments in social media or social networking services have facilitated such efforts 25,26 . Additionally, citizen science not only enables efficient research, but also provides a means of dissemination of ecology and educational roles 27,28 .…”