Browsing by Subject "reproduction"

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  • Hytönen, Timo; Kurokura, Takeshi (2020)
    Strawberry flowering physiology has engaged the interest of researchers for almost a century after the initial reports demonstrating the photoperiodic control of flowering and N egetative reproduction through stolons called runners. Most strawberries possess a seasonal flowering habit with flower initiation occurring under short days in autumn and flowering during the following spring. Also perpetual flowering genotypes are known in diploid woodland strawberry (Fragaria vesca L.) and octoploid garden strawberry (F. x ananassa Duch.), and recent research have shown that this trait has evolved independently in different species. Studies in the perpetual flowering mutant of woodland strawberry led to the identification of TERMINAL FLOWER1 (FvTFL1) as a major floral repressor causing the seasonal flowering habit in this species and demonstrated that recessive mutation in this gene leads to perpetual flowering. This breakthrough opened an avenue for molecular understanding on the control of flowering by different environmental signals. Different loci control perpetual flowering in garden strawberry including one dominant major locus and additional environmentally regulated epistatic loci. The major gene is called Perpetual Flowering Runnering (PFRU) because it also reduces the number of runners. Growth regulator applications initially demonstrated the role of gibberellin in the control of runner formation, and molecular understanding on the role of gibberellin biosynthesis and signaling in this process has started to emerge. Here, we present current understanding and major open questions on the control of flowering and runnering in strawberries. In order to understand the control of flowering in the context of perennial growth cycle, we also discuss current knowledge on the control of dormancy.
  • Pettay, Jenni E.; Lummaa, Virpi; Lynch, Robert; Loehr, John (2021)
    Because sex ratios are a key factor regulating mating success and subsequent fitness both across and within species, there is widespread interest in how population-wide sex ratio imbalances affect marriage markets and the formation of families in human societies. Although most modern cities have more women than men and suffer from low fertility rates, the effects of female-biased sex ratios have garnered less attention than male-biased ratios. Here, we analyze how sex ratios are linked to marriages, reproductive histories, dispersal, and urbanization by taking advantage of a natural experiment in which an entire population was forcibly displaced during World War II to other local Finnish populations of varying sizes and sex ratios. Using a discrete time-event generalized linear mixed-effects model, and including factors that change across time, such as annual sex ratio, we show how sex ratios, reproduction, and migration are connected in a female-dominated environment. Young childless women migrated toward urban centers where work was available to women, and away from male-biased rural areas. In such areas where there were more females, women were less likely to start reproduction. Despite this constraint, women showed little flexibility in mate choice, with no evidence for an increase in partner age difference in female-biased areas. We propose that together these behaviors and conditions combine to generate an "urban fertility trap" which may have important consequences for our understanding of the fertility dynamics of today including the current fertility decline across the developed world.
  • Kurokura, Takeshi; Samad, Samia; Koskela, Elli; Mouhu, Katriina; Hytonen, Timo (2017)
    According to the external coincidence model, photoperiodic flowering occurs when CONSTANS ( CO) mRNA expression coincides with light in the afternoon of long days (LDs), leading to the activation of FLOWERING LOCUS T (FT). CO has evolved in Brassicaceae from other Group Ia CO-like (COL) proteins which do not control photoperiodic flowering in Arabidopsis. COLs in other species have evolved different functions as floral activators or even as repressors. To understand photoperiodic development in the perennial rosaceous model species woodland strawberry, we functionally characterized FvCO, the only Group Ia COL in its genome. We demonstrate that FvCO has a major role in the photoperiodic control of flowering and vegetative reproduction through runners. FvCO is needed to generate a bimodal rhythm of FvFT1 which encodes a floral activator in the LD accession Hawaii-4: a sharp FvCO expression peak at dawn is followed by the FvFT1 morning peak in LDs indicating possible direct regulation, but additional factors that may include FvGI and FvFKF1 are probably needed to schedule the second FvFT1 peak around dusk. These results demonstrate that although FvCO and FvFT1 play major roles in photoperiodic development, the CO-based external coincidence around dusk is not fully applicable to the woodland strawberry.
  • Helosvuori, Elina (2020)
    For over four decades, feminist studies of assisted reproductive technologies (ART) have been interested in the ethical, political and personal implications of in vitro fertilization (IVF) and other infertility treatments. Most work on the implications of ART for women has focused on the demanding cyclical process of trying to become pregnant by using the technology. However, less attention has been paid to the implications of experiencing IVF after the conception phase. This article tackles the under-researched topic of the aftermath of IVF, and discusses the temporality of affective embodied experiences of infertility after one has stopped IVF. Drawing on an ethnographic study of peer support groups for the involuntarily childless in Finland, and on in-depth interviews with women suffering from infertility, this article juxtaposes two groups of women who have had IVF: those who have had children as a result of the procedure, and those who have not. The article proposes an exploration of experiences of childlessness after IVF as 'lingering technological entanglements' - that is, as affective and embodied experiences of the effects of IVF, including after the cessation of treatment. It argues that the lingering of these entanglements manifests itself in the enactment of childlessness in relation to the available technology. Furthermore, this results in parents identifying themselves as childless, even after they have gained temporal distance from IVF practices.
  • Dickel, Franziska; Freitak, Dalial; Mappes, Johanna (2016)
    Hundreds of insect species are nowadays reared under laboratory conditions. Rearing of insects always implicates the risk of diseases, among which microbial infections are the most frequent and difficult problems. Although there are effective prophylactic treatments, the side effects of applied antibiotics are not well understood. We examined the effect of prophylactic antibiotic treatment on the overwintering success of wood tiger moth (Parasemia plantaginis) larvae, and the postdiapause effect on their life-history traits. Four weeks before hibernation larvae were treated with a widely used antibiotic (fumagillin). We monitored moths' survival and life-history traits during the following 10 mo, and compared them to those of untreated control larvae. Prophylactic antibiotic treatment had no effect on survival but we show effects on some life-history traits by decreasing the developmental time of treated larvae. However, we also revealed relevant negative effects, as antibiotic treated individuals show a decreased number of laid eggs and also furthermore a suppressed immunocompetence. These results implicate, that a prophylactic medication can also lead to negative effects on life-history traits and reproductive success, which should be seriously taken in consideration when applying a prophylactic treatment to laboratory reared insect populations.
  • Candolin, Ulrika; Goncalves, Sara; Pant, Pankaj (2021)
    Recruitment is usually negatively density-dependent with fewer offspring surviving when more are produced. Parental care could alter the pattern as behaviours that maximize individual fitness are not necessarily adaptive at the population level. We manipulated the number of eggs spawned into the nests of male threespine stickleback, and found egg survival to be positively density-dependent. This reversed negative density-dependent survival observed in the absence of parental care. The reversal was caused my males investing more in parental care when receiving more eggs, while favouring future reproductive opportunities when receiving few eggs. Density-dependent parental care thus amplified changes in offspring production in relation to number of eggs spawned. Such amplification may occur in disturbed environments where human activities have altered female fecundity and males may receive more or less eggs than expected. The optimal balancing between present and future parental investment can then be distorted, resulting in maladaptive parental behaviour that reduces offspring survival. These results suggest that behaviours that have evolved to maximize individual fitness under pristine conditions can become mal-adaptive under disturbed conditions and influence the recruitment of offspring into a population. Considering that human activities are rapidly transforming environments, such mal-adaptive behavioural responses could be common and magnify negative effects of human activities on population dynamics.
  • Candolin, Ulrika; Jensen, Irene (2021)
    When environments change rapidly, evolutionary processes may be too slow to rescue populations from decline. Persistence then hinges on plastic adjustments of critical traits to the altered conditions. However, the degree to which species harbour the necessary plasticity and the degree to which the plasticity is exposed to selection in human-disturbed environments are poorly known. We show that a population of the threespine stickleback (Gasterosteus aculeatus) harbours variation in plasticity in male courtship behaviour, which is exposed to selection when visibility deteriorates because of enhanced algal growth. Females in clear water show no preference for plastic males, while females in algal-rich, turbid water switch their mate preference towards males with adaptive plasticity. Thus, while the plasticity is not selected for in the original clear water environment, it comes under selection in turbid water. However, much maladaptive plasticity is present in the population, probably because larger turbidity fluctuations have been rare in the past. Thus, the probability that the plasticity will improve the ability of the population to cope with human-induced increases in turbidity-and possibly facilitate genetic adaptation-depends on its prevalence and genetic basis. In conclusion, our results show that rapid human-induced environmental change can expose phenotypic plasticity to selection, but that much of the plasticity can be maladaptive, also when the altered conditions represent extremes of earlier encountered conditions. Thus, whether the plasticity will improve population viability remains questionable.
  • Kauffold, Johannes; Peltoniemi, Olli; Wehrend, Axel; Althouse, Gary C. (2019)
    Simply Summary: Real-time ultrasonography (RTU) has become an essential diagnostic value when assessing female swine reproduction in either individual or groups of animals. Diagnostic application of RTU is applied throughout most stages of production, including gilt development, breeding, gestation and farrowing. Along with its most common use in on-farm assessment of pregnancy status, RTU is also used to troubleshoot disruptions in reproductive performance such as delayed puberty, prolonged wean-to-estrus interval, absence of post-weaning estrus, decreased conception and farrowing rates, vulval discharge, peripartum and puerperal disorders. This review aims to provide an overview on principles and clinical uses of RTU in female reproduction on commercial swine farms. Abstract: Within the past 30 years, through ongoing technology and portability developments, real-time (b-mode) ultrasonography (RTU) has increasingly become a valuable diagnostic tool in assessing the female reproductive tract in swine. Initially applied in swine production to visually determine pregnancy status, RTU use has expanded to include assessment of the peri-pubertal and mature non-pregnant females as well. Transabdominal and transrectal modalities to visualizing the reproductive tract in swine have been reported with the transabdominal approach more common due to the fact of its ease of accessibility, animal/personnel safety, and reduced time to perform. Adjustable frequency transducers are preferred as they allow optimization of image quality at various depths. If a single transducer frequency must be selected, a 5 MHz probe provides the best versatility for visualizing the reproductive tract in swine. Other basic requirements for ultrasound equipment which will be used on commercial swine farms include being light weight and easy to handle, readily cleanable and disinfectable, long battery-life, and good durability. When using RTU for pregnancy determination, diagnosis is based upon a combination of the animal's breeding records, the presence of embryonic fluid, and, depending upon gestational stage, fetal structures. If RTU is used as a diagnostic tool in assessing reproductive problems in an individual or a group of animals, sonographic evaluation of both the uterus and ovaries is performed. Tissues are delineated and assessed based upon their echogenicity, echotexture, and size. Uses of RTU in clinical practice may include assessment of delayed puberty, prolonged wean-to-estrus interval, absence of post-weaning estrus, herd disruptions in conception and farrowing rates, vulval discharge, peripartum and puerperal disorders. This review aims to provide an overview on principles and clinical uses of RTU with respect to application to address female reproductive performance issues in commercial swine operations.
  • Candolin, Ulrika (Royal Society of London, 1998)
    An increasing number of studies show that animals adjust their reproductive e¡ort to the risk of predation. However, to maximize lifetime reproductive success this adjustment should depend on the animals' current and future reproductive potential. Here I tested this hypothesis by allowing threespine stickleback males (Gasterosteus aculeatus), differing in current and future mating probabilities, to reproduce in pools in both the presence and absence of predators. As expected, males adjusted their reproductive effort to the risk of predation. Fewer males bred, and all males developed less nuptial coloration in the presence of predators. However, males with a low current mating probability took less risk than males with a higher mating probability, whereas all males increased risk taking when future reproductive opportunities decreased. The results thus support the hypothesis that males are able to assess both the risk of predation and their current versus future mating probability, and adjust their reproductive decisions accordingly. The study further suggests that predation risk may have less effect on sexual selection than previously assumed, as the males which refrained from reproducing in the presence of predators were mainly males with a low mating probability.
  • Elgert, Christina Barbro Cecilia; Lehtonen, Topi Kasperi; Kaitala, Arja Leena; Candolin, Ulrika (2021)
  • Hällfors, Maria; Antao, Laura; Itter, Malcolm; Lehikoinen, Aleksi; Lindholm, Tanja Marjukka; Roslin, Tomas; Saastamoinen, Marjo (2020)
    Breeding timed to match optimal resource abundance is vital for the successful reproduction of species, and breeding is therefore sensitive to environmental cues. As the timing of breeding shifts with a changing climate, this may not only affect the onset of breeding but also its termination, and thus the length of the breeding period. We use an extensive dataset of over 820K nesting records of 73 bird species across the boreal region in Finland to probe for changes in the beginning, end, and duration of the breeding period over four decades (1975 to 2017). We uncover a general advance of breeding with a strong phylogenetic signal but no systematic variation over space. Additionally, 31% of species contracted their breeding period in at least one bioclimatic zone, as the end of the breeding period advanced more than the beginning. We did not detect a statistical difference in phenological responses of species with combinations of different migratory strategy or number of broods. Nonetheless, we find systematic differences in species responses, as the contraction in the breeding period was found almost exclusively in resident and short-distance migrating species, which generally breed early in the season. Overall, changes in the timing and duration of reproduction may potentially lead to more broods co-occurring in the early breeding season-a critical time for species' reproductive success. Our findings highlight the importance of quantifying phenological change across species and over the entire season to reveal shifts in the community-level distribution of bird reproduction.
  • Lakka, Hanna-Kaisa (Helsingfors universitet, 2013)
    Lepidurus arcticus (Pallas, 1793) is a keystone species in High Arctic ponds, which are exposed to a wide range of environmental stressors. This thesis provides information on the ecology of this little studied species by paying particular focus on the sensitivity of L. arcticus to acidification and climate change. Respiration, reproduction, olfaction, morphology, salinity and pH tolerance of the species were studied in the laboratory and several environmental parameters were measured in its natural habitats in Arctic ponds. Current global circulation models predict 2–2.4 °C increase in summer temperatures on Spitsbergen, Svalbard, Norway. The L. arcticus respiration activity was tested at different temperatures (3.5, 10, 16.5, 20, 25 and 30 °C). The results show that L. arcticus is clearly adapted to live in cold water and have a temperature optimum at +10 °C. This species should be considered as stenothermal, because it seems to be able to live only within a narrow temperature range. L. arcticus populations seem to have the capacity to respond to the ongoing climate change on Spitsbergen. Changes can be seen in the species' reproductive capacity and in the individuals' body size when comparing results with previous studies on Spitsbergen and in other Arctic areas. Effective reproduction capacity was a unique feature of the L. arcticus populations on Spitsbergen. L. arcticus females reached sexual maturity at a smaller body size and sexual dimorphism appeared in smaller animals on Spitsbergen than anywhere else in the subarctic or Arctic regions. L. arcticus females were able to carry more eggs (up to 12 eggs per female) than has been observed in previous studies. Another interesting feature of L. arcticus on Spitsbergen was their potential to grow large, up to 39.4 mm in total length. Also cannibalistic behaviour seemed to be common on Spitsbergen L. arcticus populations. The existence of different colour morphs and the population-level differences in morphology of L. arcticus were unknown, but fascinating characteristic of this species. Spitsbergen populations consisted of two major (i.e. monochrome and marbled) and several combined colour morphs. Third interesting finding was a new disease for science which activated when the water temperature rose. I named this disease to Red Carapace Disease (RCD). This High Arctic crustacean lives in ponds between the Arctic Ocean and glaciers, where the marine environment has a strong impact on the terrestrial and freshwater ecosystems. The tolerance of L. arcticius to increased water salinity was determined by a LC50 -test. No mortality occurred during the 23 day exposure at low 1–2 ‰ water salinity. A slight increase in water salinity (to 1 ‰) speeded up the L. arcticus shell replacement. The observations from natural populations supported the hypothesis that the size of the animals increases considerably in low 1.5 ‰ salt concentrations. Thus, a small increase in water salinity seems to have a positive impact on the growth of this short-lived species. Acidification has been a big problem for many crustaceans, invertebrates and fishes for several decades. L. arcricus does not make an exception. Strong acid stress in pH 4 caused a high mortality of mature L. arcticus females. The critical lower limit of pH was 6.1 for the survival of this acid sensitive species. Thus, L. arcticus populations are probably in danger of extinction due to acidification of three ponds on Spitsbergen. A slight drop (0.1–1.0) in pH values can wipe out these L. arcticus populations. The survival of L. arcticus was strongly related to: (1) the water pH, (2) total organic carbon (TOC) and pH interaction, (3) the water temperature and (4) the water salinity. Water pH and TOC values should be monitored in these ponds and the input of acidifying substances in ponds should be prevented.
  • Brlík, Vojtěch; Koleček, Jaroslav; Burgess, Malcolm; Hahn, Steffen; Humple, Diana; Krist, Miloš; Ouwehand, Janne; Weiser, Emily L.; Adamík, Peter; Alves, José A.; Arlt, Debora; Barišić, Sanja; Becker, Detlef; Belda, Eduardo J.; Beran, Václav; Both, Christiaan; Bravo, Susana P.; Briedis, Martins; Chutný, Bohumír; Ćiković, Davor; Cooper, Nathan W.; Costa, Joana S.; Cueto, Víctor R.; Emmenegger, Tamara; Fraser, Kevin; Gilg, Olivier; Guerrero, Marina; Hallworth, Michael T.; Hewson, Chris; Jiguet, Frédéric; Johnson, James A.; Kelly, Tosha; Kishkinev, Dmitry; Leconte, Michel; Lislevand, Terje; Lisovski, Simeon; López, Cosme; McFarland, Kent P.; Marra, Peter P.; Matsuoka, Steven M.; Matyjasiak, Piotr; Metzger, Benjamin; Monrós, Juan S.; Neumann, Roland; Newman, Amy; Norris, Ryan; Pärt, Tomas; Pavel, Václav; Perlut, Noah; Piha, Markus; Reneerkens, Jeroen; Rimmer, Christopher C.; Roberto-Charron, Amélie; Scandolara, Chiara; Sokolova, Natalia; Takenaka, Makiko; Tolkmitt, Dirk; van Oosten, Herman; Wellbrock, Arndt H. J.; Wheeler, Hazel; van der Winden, Jan; Witte, Klaudia; Woodworth, Brad; Procházka, Petr (2020)
    Currently, the deployment of tracking devices is one of the most frequently used approaches to study movement ecology of birds. Recent miniaturization of light-level geolocators enabled studying small bird species whose migratory patterns were widely unknown. However, geolocators may reduce vital rates in tagged birds and may bias obtained movement data. There is a need for a thorough assessment of the potential tag effects on small birds, as previous meta-analyses did not evaluate unpublished data and impact of multiple life-history traits, focused mainly on large species and the number of published studies tagging small birds has increased substantially. We quantitatively reviewed 549 records extracted from 74 published and 48 unpublished studies on over 7,800 tagged and 17,800 control individuals to examine the effects of geolocator tagging on small bird species (body mass
  • Långström, Bo (Suomen metsätieteellinen seura, 1984)