Experimental simulation of environmental warming selects against pigmented morphs of land snails

H-R.K. and R.T. were gratefully hosted by INRA-PACA, Avignon, France, during the time of fieldwork in 2017. We gratefully acknowledge assistance in the field and with the open-top chamber experiments by Nik Triebskorn and Tim Triebskorn. The 35 field sites were sampled within the 2018 European Theba survey initiated by H-R.K and Thomas Knigge, Le Havre University, France. We also thank Menno Schilthuizen, Leiden University, the Netherlands, and another anonymous reviewer for constructive remarks on a previous manuscript version. Open access funding enabled and organized by ProjektDEAL.In terrestrial snails, thermal selection acts on shell coloration. However, the biological relevance of small differences in the intensity of shell pigmentation and the associated thermodynamic, physiological, and evolutionary consequences for snail diversity within the course of environmental warming are still insufficiently understood. To relate temperature‐driven internal heating, protein and membrane integrity impairment, escape behavior, place of residence selection, water loss, and mortality, we used experimentally warmed open‐top chambers and field observations with a total of >11,000 naturally or experimentally colored individuals of the highly polymorphic species Theba pisana (O.F. MÜLLER, 1774). We show that solar radiation in their natural Mediterranean habitat in Southern France poses intensifying thermal stress on increasingly pigmented snails that cannot be compensated for by behavioral responses. Individuals of all morphs acted neither jointly nor actively competed in climbing behavior, but acted similarly regardless of neighbor pigmentation intensity. Consequently, dark morphs progressively suffered from high internal temperatures, oxidative stress, and a breakdown of the chaperone system. Concomitant with increasing water loss, mortality increased with more intense pigmentation under simulated global warming conditions. In parallel with an increase in mean ambient temperature of 1.34°C over the past 30 years, the mortality rate of pigmented individuals in the field is, currently, about 50% higher than that of white morphs. A further increase of 1.12°C, as experimentally simulated in our study, would elevate this rate by another 26%. For 34 T. pisana populations from locations that are up to 2.7°C warmer than our experimental site, we show that both the frequency of pigmented morphs and overall pigmentation intensity decrease with an increase in average summer temperatures. We therefore predict a continuing strong decline in the frequency of pigmented morphs and a decrease in overall pigmentation intensity with ongoing global change in areas with strong solar radiation.ProjektDEA

CONTRIBUTION TO THE ECOPHYSIOLOGY OF THE PULMONATE GASTROPOD HELIX LUCORUM L.

THE STUDIES OF BIOLOGY, ECOLOGY, ETHOLOGY, BIOMETRY, ENERGY BUDGET AND EXCRETION HAVE SHOWN THAT HELIX LUCORUM L. FROM GREECE IS CHARACTERIZED A) BY THREE GENERATIONS PER YEAR, B) IT MAY LIVE 14 YEARS OR MORE IN ORDER TO REACH ITS MAXIMUM SIZE, C) IT IS SEXUALLY MATURE WHEN THE LARGEST SHELL DIAMETER D) IN GREATER OR EQUAL TO 36MM, SIZE ATTAINED 3 YEARS AFTER ITS HATCHING, D) ITS HIBERNATION LASTS 4-5 MONTHS, E) ITS REPRODUCTIVE PERIOD IS FROM JULY TO AUGUST, IT LAYS ABOUT 50 EGGS, F) ITS MEAN ANNUAL DENSITY IS 3.39 INDIVIDUALS/M2, G) ITS ANNUAL TURNOVER RATIO (P/B) IS EQUAL TO 1.24, H) ITS ASSIMILATION RATE (A/I) IS GREATERWHEN IT IS FED WITH LACTUCA SATIVA AND LESS WHEN IT IS FED WITH URTICA DIOICA OR PETASITES ALBUS; ITS COEFFICIENT OF GROWTH EFFICIENCY (P/I) AND ITS COEFFICIENT OF ECOLOGICAL EFFICIENCY (P/A) ARE GREATER WHEN IT IS FED WITH P. ALBUS ANDLESS WHEN IT IS FED WITH U. DIOICA OR L. SATIVA. THE ABOVE PARAMETERS ASCILLATE WITH THE AGE, THE SEASON OR THE PHYSIOLOGY OF THE ANIMALS. I) H. LUCORUM IS URICOTELIC ALTHOUGH ITS URICOTELIC CHAIN IS COMPLETE.Η ΜΕΛΕΤΗ ΤΗΣ ΒΙΟΛΟΓΙΑΣ, ΟΙΚΟΛΟΓΙΑΣ, ΗΘΟΛΟΓΙΑΣ, ΒΙΟΜΕΤΡΙΑΣ, ΕΝΕΡΓΕΙΑΚΟΥ ΙΣΟΖΥΓΙΟΥ ΚΑΙ ΤΗΣ ΑΠΕΚΚΡΙΣΗΣ ΤΟΥ HELIX LUCORUM L. ΣΤΗΝ ΕΛΛΑΔΑ ΕΔΕΙΞΕ ΟΤΙ ΤΟ ΗΘΟΣ ΑΥΤΟ ΠΑΡΟΥΣΙΑΖΕΙ ΤΑ ΕΞΗΣ, ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ: Α) ΕΧΕΙ ΤΡΕΙΣ ΓΕΝΙΕΣ ΤΟ ΧΡΟΝΟ, Β) ΜΠΟΡΕΙ ΝΑΖΗΣΕΙ 14 'Η ΠΕΡΙΣΣΟΤΕΡΑ ΧΡΟΝΙΑ ΓΙΑ ΝΑ ΦΘΑΣΕΙ ΤΟ ΜΕΓΙΣΤΟ ΜΕΓΕΘΟΣ ΤΟΥ, Γ) ΕΙΝΑΙ ΓΕΝΝΗΤΙΚΑ ΩΡΙΜΟ ΟΤΑΝ Η ΜΕΓΑΛΗ ΔΙΑΜΕΤΡΟΣ ΤΟΥ ΚΕΛΥΦΟΥΣ ΤΟΥ (D) ΓΙΝΕΙ ΙΣΗ 'Η ΜΕΓΑΛΥΤΕΡΗ ΑΠΟ 36 ΜΜ. ΤΑ ΣΑΛΙΓΚΑΡΙΑ ΦΘΑΝΟΥΝ ΑΥΤΟ ΤΟ ΜΕΓΕΘΟΣ 3 ΧΡΟΝΙΑ ΜΕΤΑ ΤΗΝ ΕΚΟΛΑΨΗ Δ) Η ΧΕΙΜΕΡΙΑ ΝΑΡΚΗ ΔΙΑΡΚΕΙ 4-5 ΜΗΝΕΣ, Ε) Η ΑΝΑΠΑΡΑΓΩΓΙΚΗ ΤΟΥ ΠΕΡΙΟΔΟΣ ΔΙΑΡΚΕΙ ΔΥΟ ΠΕΡΙΠΟΥ ΜΗΝΕΣ, ΤΟΝ ΙΟΥΛΙΟ ΚΑΙ ΑΥΓΟΥΣΤΟ ΤΑ ΣΑΛΙΓΚΑΡΙΑ ΑΠΟΘΕΤΟΥΝ ΠΕΡΙΠΟΥ 50ΑΥΓΑ, ΣΤ) Η ΜΕΣΗ ΕΤΗΣΙΑ ΠΥΚΝΟΤΗΤΑ ΕΙΝΑΙ 3.39 ΑΤΟΜΑ/Μ2, Ζ) Η ΕΤΗΣΙΑ ΙΚΑΝΟΤΗΤΑ ΑΝΑΝΕΩΣΗΣ ΒΙΟΜΑΖΑΣ (Ρ/Β) ΙΣΟΥΤΑΙ ΜΕ 1.24, Η) Ο ΣΥΝΤΕΛΕΣΤΗΣ ΑΦΟΜΟΙΩΣΗΣ (Α/Ι) ΠΑΡΟΥΣΙΑΖΕΙ ΜΕΓΑΛΥΤΕΡΕΣ ΤΙΜΕΣ ΟΤΑΝ ΤΑ ΣΑΛΙΓΚΑΡΙΑ ΤΡΕΦΟΝΤΑΙ ΜΕ ΜΑΡΟΥΛΙ (LACTUCA SATIVA) ΚΑΙ ΜΙΚΡΟΤΕΡΕΣ ΟΤΑΝ ΤΡΕΦΟΝΤΑΙ ΜΕ ΤΣΟΥΚΝΙΔΑ (URTICA DIOICA) 'Η ΠΛΑΤΙΜΑΝΔΥΛΑ (PETASITES ALBUS). Ο ΣΥΝΤΕΛΕΣΤΗΣ ΙΚΑΝΟΤΗΤΑΣ ΑΥΞΗΣΗΣ (Ρ/Ι) ΚΑΙ Ο ΣΥΝΤΕΛΕΣΤΗΣ ΟΙΚΟΛΟΓΙΚΗΣ ΑΠΟΤΕΛΕΣΜΑΤΙΚΟΤΗΤΑΣ (Ρ/Α) ΠΑΡΟΥΣΙΑΖΟΥΝ ΜΕΓΑΛΥΤΕΡΕΣ ΤΙΜΕΣ ΟΤΑΝ ΤΑ ΣΑΛΙΓΚΑΡΙΑ ΤΡΕΦΟΝΤΑΙ ΜΕ ΠΛΑΤΥΜΑΝΔΥΛΑ ΚΑΙ ΟΤΑΝ ΤΡΕΦΟΝΤΑΙ ΜΕ ΤΣΟΥΚΝΙΔΑ 'Η ΜΑΡΟΥΛΙ. ΟΙ ΠΑΡΑΠΑΝΩ ΣΥΝΤΕΛΕΣΤΕΣ ΠΑΡΟΥΣΙΑΖΟΥΝ ΔΙΑΚΥΜΑΝΣΕΙΣ ΑΝΑΛΟΓΑ ΜΕ ΤΗΝ ΗΛΙΚΙΑ, ΤΗΝ ΕΠΟΧΗ'Η ΤΗ ΦΥΣΙΟΛΟΓΙΚΗ ΚΑΤΑΣΤΑΣΗ ΤΩΝ ΖΩΩΝ, Θ) ΣΤΟ Η. LUCORUM Ο ΚΑΤΑΒΟΛΙΣΜΟΣ ΤΟΥ ΑΖΩΤΟΥ ΕΧΕΙ ΟΥΡΙΚΟΤΕΛΙΚΟ ΧΑΡΑΚΤΗΡΑ ΑΝ ΚΑΙ Η ΟΥΡΙΚΟΤΕΛΙΚΗ ΕΝΖΥΜΑΤΙΚΗ ΑΛΥΣΙΔΑ ΕΙΝΑΙ ΠΛΗΡΗΣ

Intraspecific morphological variation of the sperm storing organ in two hermaphroditic land snail species

Abstract Background Postcopulatory sexual selection is very important in species with reproductive strategies that involve multiple mating and prolonged sperm storage. The sperm storage organ has been hypothesized to evolve in response to different levels of sperm competition in several species while population density has been considered as a factor that approximates sperm competition risk and intensity in the field. Apart from population density, local microclimatic conditions may also play a role in determining sperm competition levels in natural populations of land snails by affecting their chances of encountering mates. The goal of this study was to investigate the variation of the structure of the sperm storage organ in the simultaneously hermaphroditic land snails Helix lucorum and Cepaea vindobonensis occurring sympatrically in two sites which differed in habitat humidity. The populations of both species from the two sites, also differed in density and in duration of reproductive period. Multiple samples were taken from each population in order to test for temporal variation. Results In both species, the spermatheca consisted of a simple fertilization chamber and a variable number of lateral tubules. The length of the spermatheca showed no temporal or spatial differentiation nor did it show any correlation with snail size. The number of tubules in Helix lucorum ranged from five to sixteen and in Cepaea vindobonensis from one to eight and in both species a significant difference of this trait between the two study sites was detected. In Cepaea vindobonensis, the difference in tubule number led to difference of the total tubule length which reflects sperm storage capacity of the spermatheca but this was not the case with H. lucorum in which no increase in total tubule length was detected. Conclusions Intraspecific variation in the spermatheca was observed in both snail species studied. The variation observed was independent of snail size, and reproduction status, while the two species responded differently to higher sperm competition levels

An Assessment of Snail-Farm Systems Based on Land Use and Farm Components

In this study, the structural and management characteristics of snail farms in Greece were analyzed to maximize sustainable food production. Objectives, such as the classification of farming systems and assessing the effects of various annual production parameters, were investigated. Data were collected (2017) via a questionnaire, and sampling was conducted in 29 snail farms dispersed in six different regions (Thrace, Central Macedonia, West Macedonia, Thessaly, Western Greece, and the Attica Islands). Descriptive statistics for continuous variables and frequencies for categorical variables were calculated. The similarity between farms was analyzed using nonmetric multidimensional scaling (nMDS). The average farm operation duration exceeded eight months and the mean annual production was 1597 kg of fresh, live snails. Results recorded five farming systems: elevated sections (7%), net-covered greenhouse (38%), a mixed system with a net-covered greenhouse (10%), open field (38%), and mixed system with an open field (7%). Snail farms differ in the type of substrate, available facilities, and equipment (60% similarity between most of the open field farms). The geographical location of a farms’ settlement affects productivity but also influences the duration of operation, especially in open field farms, due to their operation under a wide assortment of climatic types

High level of sperm competition may increase transfer of accessory gland products carried by the love dart of land snails

Postcopulatory adaptations that increase reproductive success compared to rivals, like the transfer of accessory gland products that promote paternity, are common when sperm competition occurs among males. In land snails, the dart shooting behavior and its adaptive significance, in promoting individual fitness through enhanced paternity of the successful dart shooter, have been considered such an adaptation. The fitness result gained is mediated by the transfer of mucus components on the love dart capable of altering the physiology of the receiver's reproductive tract. In this context, dart shooting and mucus transfer could be considered as processes targeted by sexual selection. While the effect of dart mucus is beneficial for the dart user, so far it has remained unknown whether its transport is greater when snails experience a higher level of sperm competition. Here, we report results of a study on inter- and intraspecific variations of dart and mucus gland morphometry, considered to be traits reflecting the ability of snails to adjust the production and transfer of mucus under varying sperm competition scenarios. We investigated four populations with different densities from four dart-bearing species, Arianta arbustorum, Cepaea nemoralis, Cornu aspersum, and Helix lucorum. The results indicate that different adaptations of these traits occur among the studied species that all seem to achieve the same goal of transferring more mucus when sperm competition is higher. For example, the presence of longer and more branched mucous glands or an increase in dart surface most likely reflect increased mucus production and enhanced ability of mucus transport, respectively. Interestingly, the species for which the use of the dart is reported to be facultative, A. arbustorum, did not show any variation among the examined traits. To conclude, sexual selection in the form of sperm competition intensity seems to be an important selective force for these simultaneously hermaphroditic dart-bearing snails, driving differences in sexual traits

Dominant gingers – Discovery and inheritance of a new shell polymorphism in the great pond snail Lymnaea stagnalis

Abstract Color polymorphism is a classic study system for evolutionary genetics. One of the most color‐polymorphic animal taxa is mollusks, but the investigation of the genetic basis of color determination is often hindered by their life history and the limited availability of genetic resources. Here, we report on the discovery of shell color polymorphism in a much‐used model species, the great pond snail Lymnaea stagnalis. While their shell is usually beige, some individuals from a Greek population show a distinct red shell color, which we nicknamed Ginger. Moreover, we found that the inheritance fits simple, single‐locus Mendelian inheritance with dominance of the Ginger allele. We also compared crucial life‐history traits between Ginger and wild‐type individuals, and found no differences between morphs. We conclude that the relative simplicity of this polymorphism will provide new opportunities for a deeper understanding of the genetic basis of shell color polymorphism and its evolutionary origin

Bateman gradients in hermaphrodites : an extendes approach to quantify sexual selection

Sexual selection is often quantified using Bateman gradients, which represent sex-specific regression slopes of reproductive success on mating success and thus describe the expected fitness returns from mating more often. Although the analytical framework for Bateman gradients aimed at covering all sexual systems, empirical studies are biased toward separate-sex organisms, probably because important characteristics of other systems remain incompletely treated. Our synthesis complements the existing Bateman gradient approach with three essential reproductive features of simultaneous hermaphrodites. First, mating in one sex may affect fitness via the opposite sex, for example, through energetic trade-offs. We integrate cross-sex selection effects and show how they help characterizing sexually mutualistic versus antagonistic selection. Second, male and female mating successes may be correlated, complicating the interpretation of Bateman gradients. We show how to quantify the impact of this correlation on sexual selection and propose a principal component analysis on male and female mating success to facilitate interpretation. Third, self-fertilization is accounted for by adding selfed progeny as a separate category of reproductive success to analyses of Bateman gradients. Finally, using a worked example from the snail Biomphalaria glabrata, we illustrate how the extended analytical framework can enhance our understanding of sexual selection in hermaphroditic animals and plants

Effects of Intravenous Versus Epidural Lidocaine Infusion on Pain Intensity and Bowel Function After Major Large Bowel Surgery: a Double-Blind Randomized Controlled Trial

We compared the effects of intravenous lidocaine (IVL) with lumbar epidural lidocaine analgesia (LEA) on pain and ileus after open colonic surgery. Between December 2011 and February 2013, 60 patients were randomly allocated to IVL, LEA, or control group. The IVL group received intraoperatively lidocaine 2 % intravenously (1.5 mg/kg bolus, 2 mg/kg/h infusion) and normal saline (NS) epidurally. The LEA group received lidocaine epidurally (1.5 mg/kg bolus, 2 mg/kg/h infusion) and NS intravenously. The control group received NS both intravenously and epidurally, as bolus and infusion. All NS volumes were calculated as if containing lidocaine 2 % at the aforementioned doses. We assessed pain intensity at rest/cough at 1, 2, 4, 12, 24, and 48 h postoperatively (numerical rating scale 0-10), 48-h analgesic consumption, and time to first flatus passage. Data from 60 patients (20 per group) were analyzed. The IVL group had significantly lower pain scores at rest and cough compared to LEA or control group only at 1, 2, and 4 h postoperatively (P < 0.005 for all comparisons). The 48-h analgesic requirements and time to first flatus passage did not differ significantly between IVL group and LEA or control group (P > 0.05). Compared with LEA-lidocaine or placebo, intravenous lidocaine offered no clinically significant benefit in terms of analgesia and bowel function

How Safe to Eat Are Raw Bivalves? Host Pathogenic and Public Health Concern Microbes within Mussels, Oysters, and Clams in Greek Markets

Raw-bivalves consumption is a wide trend in Mediterranean countries. Despite the unambiguous nutritional value of seafood, raw consumption of bivalves may involve risks that could pose a significant threat to consumers’ health. Their filter-feeding behavior is responsible for the potential hosting of a wide variety of microorganisms, either pathogenic for the bivalves or public health threats. Under this prism, the current study was conducted in an effort to evaluate the risk of eating raw bivalves originating from the two biggest seafood markets in Thessaloniki, the largest production area of bivalves in Greece. Both microbiological and molecular methodologies were applied in order to assess the presence of various harmful microbes, including noroviruses, Bonamia, Marteilia, Esherichia coli, Salmonella, and Vibrio. Results indicated the presence of several Vibrio strains in the analyzed samples, of which the halophilic Vibrio harveyi was verified by 16S rRNA sequencing; other than this, no enteropathogenic Vibrio spp. was detected. Furthermore, although Esherichia coli was detected in several samples, it was mostly below the European Union (EU) legislation thresholds. Interestingly, the non-target Photobacterium damselae was also detected, which is associated with both wound infections in human and aquatic animals. Regarding host pathogenic microorganisms, apart from Vibrio harveyi, the protozoan parasite Marteilia refrigens was identified in oysters, highlighting the continuous infection of this bivalve in Greece. In conclusion, bivalves can be generally characterized as a safe-to-eat raw food, hosting more bivalve pathogenic microbes than those of public health concern

Different Interspecies Demographic Histories within the Same Locality: A Case Study of Sea Cucumbers, Cuttlefish and Clams in Greek Waters

Coalescent methods in population genetics aim to detect biodiversity patterns, evolutionary mechanisms, and signatures of historical changes in effective population sizes with respect to the species fidelity. Restriction site-associated DNA sequencing (RADseq) was used to evaluate the population dynamics of invertebrate species within the same localities. New sequencing technologies, such as the ones employed by population genetics, could be used to improve the management and sustainability of marine and aquaculture resources. Sea cucumbers (Holothuria tubolosa) showed genetic differentiation patterns favoring limited gene flow between studied areas. Similar results for clams (Venus verrucosa) suggest local adaptation and low-dispersal abilities for sessile organisms. On the contrary, cuttlefish (Sepia officinalis) exhibited a panmictic pattern, resulting in a single genetic stock in the area. The larvae settlement duration may be responsible for such interspecies variations. Interspecies demographic modeling revealed different environmental pressures of historical events’ signatures with respect to the three invertebrates. Sea cucumbers favor a post-glacial bottleneck event followed by a more recent recovery, whereas cuttlefish favor an expansion before the late glacial maximum. Lastly, clams showed a constant effective population size in the area. The results of historical demographic changes in natural populations provide opportunities for critical evaluation and management in terms of the conservation of the species in the area