Optimality and trait based approaches to sympatric speciation and sympatric co-evolution of predator and prey traits in marine plankton

Marine microorganisms are responsible for roughly half of the Earth’s primary production, circa half of the carbon dioxide sink and oxygen production on Earth. Marine plankton organisms are an important part of global biogeochemical models, which simulate the effects of current global change, e.g., increased CO2 levels, increased temperature, or increased eutrophication on ecosystem functioning and community dynamics. However, such models rarely account for the adaptation of marine microorganisms, which are able to evolve rapidly. While some global models deal with the extinction of species and loss of biodiversity, they do not account for speciation. Due to a highly unstructured marine environment with no clear boundaries, understanding sympatric speciation, which is the speciation without geographic isolation, in plankton is particularly important. However, sympatric speciation in terrestrial systems has gained much more attention while in marine systems it was largely ignored. The most famous example of sympatric speciation are Darwin’s finches, which diversified by specialisation on different resources. But despite the large number of existing speciation models, a concrete mechanism which allows for sympatric speciation via specialisation, as suggested by Darwin, has been difficult to pin down. Therefore, in the first part of the thesis we propose a concrete mechanism of sympatric speciation via specialisation and resource partitioning allowing predators to reduce competition and create new ecological niches. The key to this mechanism are the reduced costs in the specialisation trade-off, whereby the improved ability to eat the preferred prey (gain) over-compensates the reduced ability to eat the less-preferred prey (cost). Such "plus-zero sum game” increases the grazing pressure on prey, which in turn may respond by changing traits, e.g., the specific growth rate, in order to escape the grazing pressure. Building on this mechanism, in the second part of the thesis we explore sympatric speciation in the face of simultaneous co-evolution of a prey trait (growth rate) and a predator trait (specialisation) in a simple predator-prey interaction model. We find that the space defined by all combinations of predator and prey traits can be divided into three regions: (1) the speciation space, where the combinations of traits allow speciation leading to the establishment of two sympatric predator species; (2) the vanishing speciation space, i.e. the range of combinations allowing only ephemeral speciation and (3) the displacement space, where the resident predator is displaced by a single mutant. We also introduce and discuss some further novel concepts, e.g., evolutionary time landscape, speciation threshold and prey-equality space. We conclude that prey species can adjust traits as a response to increased predation. This raises the question of how both trophic levels would adapt to changing environmental conditions. While some studies investigated the evolutionary response of marine plankton to increased temperature, CO2 and acidification, changes in the marine biodiversity as a consequence of increased nutrient concentration (i.e. eutrophication) has not been intensively studied yet. Moreover, the density-independent mortality (DIM) in the ocean was largely ignored and not treated separately from the grazing mortality. Hence, in the third part of the thesis we examine the occurrence of sympatric speciation and the dynamics of a marine plankton community as a function of three changing quantities: environmental nutrient load, DIM of phytoplankton, and adaptive specialisation of zooplankton. Particularly we study the coevolution of plankton and the resource use efficiency in a four-species predator-prey interaction model at different environmental nutrient concentrations and density-independent mortalities of the prey. The results imply that increasing nutrient concentration in our model: (1) promotes biodiversity, (2) decreases the effect of DIM of phytoplankton on biodiversity, (3) changes domination from prey species to predators, and (4) decreases overall system productivity. This thesis emphasises the importance of traits and trade-offs for understanding the adaptive behavior of marine plankton. Fast evolutionary changes and density-independent crashes of populations in marine plankton necessitate the consideration and better representation of evolutionary processes in global biogeochemical models in order to better project the impacts of climate change on marine ecosystems. Sympatric speciation deserves particular attention due to the absence of clear geographic barriers in the marine environment

Retrospective Evaluation of Method of Treatment, Laboratory Findings, and Concurrent Diseases in Dairy Cattle Diagnosed with Left Displacement of the Abomasum during Time of Hospitalization

Simple Summary Left displacement of the abomasum (LDA) is a common disease in high-producing dairy cattle, resulting in direct and indirect costs, discomfort for the cattle, and death if not treated. The objectives of this retrospective study were to assess the effect of treatment on recovery from LDA during time of hospitalization, to investigate the influence of concurrent diseases on the recovery, and to identify prognostic indicators in laboratory findings. Neither the number of concurrent diseases nor the method of surgery had any influence on the outcome (death or recovery). The most common concurrent disease was metritis/endometritis (38.4% of cows). Conservative treatment (abomasal rolling) was successful in 92.8% of cows, with a recurrence rate of 56.7%. Neither oral nor analgesic therapy had any influence on the recurrence of LDA following abomasal rolling during hospitalization. In cows undergoing surgery, endoscopic abomasopexy as described by Janowitz and right flank laparotomy were performed most often (40.8% and 40.2%, respectively). A significantly (p < 0.01) higher number of cows showed the outcome recovery compared with death. The results of this study indicate that the outcome after surgery for LDA under clinical conditions does not depend on the method of surgery, and that concurrent diseases are often diagnosed in cattle with LDA. Conservative treatment has a high recurrence rate. Left displacement of the abomasum (LDA) is a disease often diagnosed in high-producing dairy cattle, resulting in direct and in indirect costs for the farmer, and discomfort and death for the cows. For the present retrospective study, the aims were to assess the effect of treatment on recovery during the time of hospitalization of the cows, to investigate the influence of concurrent diseases on the recovery, and to identify prognostic indicators in laboratory findings. Metritis/endometritis (38.4% of cows) was the concurrent disease diagnosed most often. Conservative treatment (abomasal rolling) was performed successfully in 92.8% of cows;the recurrence rate was 56.7%. Neither treatment with an oral drench nor treatment with analgesics had any influence on the recurrence of LDA following abomasal rolling during hospitalization. Endoscopic abomasopexy as described by Janowitz was performed more often than right flank laparotomy (40.8% and 40.2%, respectively). A significantly (p < 0.01) higher number of cows had the outcome recovery compared with death. The results of this study show that the outcome after surgery for LDA under clinical conditions does not depend on the method of surgery. Moreover, cows with LDA often suffer from concurrent diseases. If conservative treatment is decided on, farmers should be informed that there is a high recurrence rate, and other treatment options should be discussed

Retrospective analysis of 302 ovine dystocia cases presented to a veterinary hospital with particular attention to uterine torsion

Background Dystocia is common in sheep, and foetal causes are predominant. Among maternal causes, insufficient cervical dilatation is the most frequent problem. Uterine torsion has been considered rare by many authors. Objectives This study was conducted to investigate causes of dystocia in sheep presented for veterinary attention, and particular focus was set on the description of uterine torsion and analysis of potentially predisposing factors for this condition. Methods Clinical records of 302 sheep treated for dystocia were evaluated retrospectively. Known and proposed risk factors for uterine torsion in cattle were analysed regarding their potential importance in sheep. These included lamb birth weights, ewe age, parity, season, nutrition, breed type, litter size and husbandry. Results Maternal causes of dystocia accounted for 67.2% (203/302) of the presented cases. Of these, insufficient cervical dilatation (121/203, 59.6%) was the most frequent diagnosis. Another substantial proportion of maternal causes (60/203, 29.6%) was identified as uterine torsion. Husbandry, breed type and litter size showed significance in univariate analyses, with lower odds for meat breeds (OR 0.22; p < 0.001), twin- (OR 0.49; p = 0.020) or multiple-bearing ewes (OR 0.19; p = 0.013) and higher odds for fully housed animals (OR 17.87; p < 0.001). Year-round housing was identified as the most influential factor in a subsequent multivariate analysis. Conclusions Uterine torsion was identified as a relevant cause of dystocia in our case load. The condition is likely to be underdiagnosed in sheep, and increased farmer and veterinary awareness is necessary to ensure adequate treatment of affected animals and to prevent unnecessary suffering

Comparison of Transmittance and Reflectance Pulse Oximetry in Anesthetized Dogs

Objectives: The tongue is the standard site for placement of a pulse oximeter probe but is difficult to access during certain procedures such as dental and ophthalmic procedures and computerized tomography of the head. The aim of this study was to evaluate the performance of a new-generation reflectance pulse oximeter using the tail and tibia as sites for probe attachment. Materials and Methods: A total of 100 client-owned dogs that underwent anesthesia for various reasons were premedicated with butorphanol (n = 50; 0.2 mg/kg; group BUT) or butorphanol and dexmedetomidine (n = 50; 5 μg/kg; group DEX), administered intravenously. Anesthesia was induced with propofol and maintained with sevoflurane. A transmittance pulse oximeter probe was placed on the tongue and served as the reference standard. A reflectance probe was randomly placed on the tail base or the proximal tibia, and the position changed after testing. Signals from three consecutive measurements were obtained at each position. Failure was defined as “no signal,” “low signal,” or a pulse difference >10/min compared with the ECG heart rate. Data were analyzed using chi-square test, Wilcoxon matched-pair signed-rank test, and Bland-Altman analysis. P < 0.05 was considered significant. Results: In both groups (BUT and DEX), failure rate was higher when the tibia and tail were used as probe sites compared with the tongue. In both groups, the failure rate was higher for the tibia than for the tail. Dexmedetomidine-induced vasoconstriction increased failure rate at all probe positions. Clinical Significance: The tail base, but not the tibia, is an acceptable position for reflectance pulse oximeter probes in dogs. The tongue remains the probe site of choice, if accessible

Evaluation of barometric whole-body plethysmography for therapy monitoring in cats with feline lower airway disease

Objectives Feline lower airway disease (FLAD) is a common respiratory condition in cats. Traditionally, response to therapy is monitored only by evaluation of clinical signs and radiographic examination of the lungs. Barometric whole-body plethysmography (BWBP) is considered a non-invasive, well-tolerated form of measuring airway reactivity in cats. The aim of the study was to assess pulmonary function testing by BWBP for non-invasive evaluation of response to therapy in cats with FLAD and to investigate whether BWBP parameters correlate with clinical severity. Material and methods The prospective study included 25 client-owned cats, diagnosed with FLAD on the basis of their medical history, clinical signs, radiographic findings, and bronchoalveolar lavage fluid (BALF) examination. At three time points (day 0, 14, and 60), a standardised owner questionnaire, a clinical examination and BWBP measurements were carried out. Results of the questionnaire and the clinical examination were evaluated using a clinical 12-point score. Individual therapy was administered to all patients after diagnosis, based on the severity of disease and compliance of the cat. Results The total clinical score significantly improved over the entire study period (p<0.001). Significant improvement was detected for the frequency of coughing (p = 0.009), respiratory distress (p = 0.001), lung auscultation findings (p = 0.002), and general condition and appetite (p = 0.045). The BWBP parameter Penh, an indicator of bronchoconstriction, improved significantly under initial therapy between day 0 and 14 (p = 0.009). A significant correlation between Penh and the severity of auscultation findings was seen on day 0 (r = 0.40; p = 0.013). Conclusion The study supports the role of Penh as a non-invasive parameter for monitoring initial treatment response in cats with FLAD. Further studies are needed to address whether other BWBP parameters might be suitable for non-invasive therapy monitoring of FLAD. Clinical evaluation is always essential in cats with FLAD to evaluate treatment response

Antibody Response to Canine Adenovirus-2 Virus Vaccination in Healthy Adult Dogs

Background: Re-vaccination against canine adenovirus (CAV) is performed in ≤3-year-intervals but its necessity is unknown. The study determined anti-CAV antibodies within 28 days of re-vaccination and factors associated with the absence of antibodies and vaccination response. Methods: Ninety-seven healthy adult dogs (last vaccination ≥12 months) were re-vaccinated with a modified live CAV-2 vaccine. Anti-CAV antibodies were measured before vaccination (day 0), and after re-vaccination (day 7, 28) by virus neutralization. A ≥4-fold titer increase was defined as vaccination response. Fisher’s exact test and multivariate regression analysis were performed to determine factors associated with the absence of antibodies and vaccination response. Results: Totally, 87% of dogs (90/97; 95% CI: 85.61–96.70) had anti-CAV antibodies (≥10) before re-vaccination. Vaccination response was observed in 6% of dogs (6/97; 95% CI: 2.60–13.11). Time since last vaccination (>3–5 years, OR = 9.375, p = 0.020; >5 years, OR = 25.000, p = 0.006) was associated with a lack of antibodies. Dogs from urban areas were more likely to respond to vaccination (p = 0.037). Conclusion: Many dogs had anti-CAV pre-vaccination antibodies, even those with an incomplete vaccination series. Most dogs did not respond to re-vaccination. Based on this study, dogs should be re-vaccinated every 3 years or antibodies should be determined

Evaluation of a Point-of-Care Test for Pre-Vaccination Testing to Detect Antibodies against Canine Adenoviruses in Dogs

(1) Background: Antibody testing is commonly used to assess a dog’s immune status. For detection of antibodies against canine adenoviruses (CAVs), one point-of-care (POC) test is available. This study assessed the POC test´s performance. (2) Methods: Sera of 198 privately owned dogs and 40 specific pathogen-free (SPF) dogs were included. The reference standard for detection of anti-CAV antibodies was virus neutralization (VN) using CAV-1 and CAV-2 antigens. Specificity, sensitivity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy (OA) of the POC test were assessed. Specificity was considered most important. (3) Results: Prevalence of CAV-1 neutralizing antibodies (≥10) was 76% (182/238) in all dogs, 92% (182/198) in the subgroup of privately owned dogs, and 0% (0/40) in SPF dogs. Prevalence of CAV-2 neutralizing antibodies (≥10) was 76% (181/238) in all dogs, 91% (181/198) in privately owned dogs, and 0% (0/40) in SPF dogs. Specificity for detection of CAV-1 antibodies was lower (overall dogs, 88%; privately owned dogs, 56%; SPF dogs, 100%) compared with specificity for detection of CAV-2 antibodies (overall dogs, 90%; privately owned dogs, 65%; SPF dogs, 100%). (4) Conclusions: Since false positive results will lead to potentially unprotected dogs not being vaccinated, specificity should be improved to reliably detect anti-CAV antibodies that prevent infectious canine hepatitis in dogs

Wellbeing, quality of life, presence of concurrent diseases, and survival times in untreated and treated German Shepherd dogs with dwarfism

Background Pituitary dwarfism (PD) in German Shepherd dogs (GSD) is a rare endocrinopathy. Cause and inheritance of the disease are well characterized, but the overall survival time, presence of concurrent diseases, quality of life (QoL) and influence of different treatment options on those parameters is still not well investigated. The aim of this study was to obtain data regarding the disease pattern of GSD with PD and to investigate the impact of treatment. Methods 47 dogs with dwarfism (presumably PD) and 94 unaffected GSD serving as controls were enrolled. Data were collected via a standardized questionnaire, which every owner of a participating dog had completed. Dogs with PD were grouped based on three categories of treatment: Group 1 (untreated), group 2 (treated with levothyroxine), group 3 (treated with thyroxine and progestogens or with growth hormone (GH)). Groups were compared using One-Way-Anova, Kruskal-Wallis test or Wilcoxon-rank-sum test. Categorical analysis was performed using Two-Sample-Chi-Squared-test. Results Dogs treated with thyroxine and gestagen or GH were significantly taller and heavier compared to all other dogs with PD. Quality of life was best in dogs with PD treated with thyroxine and similar to unaffected GSD. Treatment increased survival time in dogs with PD independent of the treatment strategy. Dogs receiving thyroxine and progestogens or GH did not develop chronic kidney disease (CKD). Conclusion GSD with PD should be treated at least for their secondary hypothyroidism to increase survival time. Additional treatment with progestogens or GH improves body size and seems to protect against the occurrence of CKD

Relationship of body condition and milk parameters during lactation in Simmental cows in Bavaria, Germany

In dairy cows the body condition forms a reflection of the energy reserves of the organism. Health, welfare and productivity of dairy cows are strongly associated with changes in body condition. As lactation puts substantial demands on the metabolism of dairy cows, farm management aims at avoiding either a deficient body condition or a substantial loss of body condition within a short period of time. A body condition higher or lower than recommended (over- and underconditioning in the following) compromises dairy cow productivity. While the body condition of Holstein Friesian cows has been thoroughly explored, few is known about the consequences of deviations from a target body condition for health and productivity of cows from other breeds. This study explores the percentage of over- and underconditioned cows at different days post partum [dpp] and their association with production parameters i.e., milk yield, milk fat and milk protein content of Simmental cows on Bavarian farms, categorized by parity (primi- or multiparous). Our study displays that in Simmental cows, overconditioning is more prevalent than underconditioning. While the middle of lactation (dpp = 100–199) resulted in higher percentage of overconditioning, the dry period (dpp = 299) indicated a higher percentage of underconditioned cows. The dry period and the middle of lactation are therefore the most challenging lactation stages for Simmental cows. We found milk protein content to have the strongest association with over- and underconditioning in Simmental cows. The probability of overconditioning was higher with higher milk protein content for every lactation stage and the probability of underconditioning was lower with higher milk protein content in every lactation stage. This study provides a theoretical basis for potential improvements in stockbreeding, which, if implemented, could improve not only the milk yield of Simmental dairy cows, but also their health and welfare

Rumen and Liver Fluke Infections in Sheep and Goats in Northern and Southern Germany

Simple Summary Little is known about the distribution of rumen and liver flukes in sheep and goats in Germany or about the occurring rumen fluke species. These fluke infections can be detected by the parasite's eggs in the host animal's feces. Therefore, fecal samples from 223 sheep farms and 143 goat farms from northern and southern Germany were examined. The eggs of rumen flukes were detected on 2.2% of the samples, the eggs of common liver flukes on 2.7%, and the eggs of small liver flukes on 21.1% of the examined sheep farms. The rumen flukes were identified as the emerging species Calicophoron daubneyi. No rumen fluke eggs were detected on any of the goat farm samples, but common and small liver fluke eggs were detected in 5.6% and 7.0% of the goat herds, respectively. Differences in the geographical distribution of rumen and liver flukes between and within the two regions were identified. Rumen flukes were more frequently found in the north, while the two liver fluke species were more frequently found in the south of Germany. Sheep sharing the pasture with other ruminants were more likely to be infected with rumen flukes. Paramphistomidosis has recently been identified as an emerging parasitosis in Europe. This study estimated the prevalence of rumen flukes, Fasciola hepatica and Dicrocoelium dendriticum, in small ruminants in Germany and identified occurring rumen fluke species and potential predictors for fluke infections. Pooled fecal samples from 223 sheep farms and 143 goat farms in northern and southern Germany were examined by the sedimentation technique, and molecular species identification was performed on rumen-fluke-positive samples. In sheep, a flock prevalence of 2.2% was detected for rumen flukes. Calicophoron daubneyi was identified on four of five positive farms, while species identification failed in one flock. No rumen fluke eggs were detected in the examined goat herds. F. hepatica eggs were detected in 2.7% of the sheep flocks, while the herd prevalence was 5.6% in goats. Higher prevalence values of 21.1% (sheep) and 7.0% (goats) were observed for D. dendriticum. Mixed grazing with other ruminants and previously identified infections with rumen flukes and/or F. hepatica were identified as predictors for paramphistomidosis. The distribution of the three trematode species followed a geographical pattern associated with conditions favoring the relevant intermediate hosts. C. daubneyi is an established parasite in German sheep at a currently low prevalence