The role of active movement in fungal ecology and community assembly

Movement ecology aims to provide common terminology and an integrative framework of movement research across all groups of organisms. Yet such work has focused on unitary organisms so far, and thus the important group of filamentous fungi has not been considered in this context. With the exception of spore dispersal, movement in filamentous fungi has not been integrated into the movement ecology field. At the same time, the field of fungal ecology has been advancing research on topics like informed growth, mycelial translocations, or fungal highways using its own terminology and frameworks, overlooking the theoretical developments within movement ecology. We provide a conceptual and terminological framework for interdisciplinary collaboration between these two disciplines, and show how both can benefit from closer links: We show how placing the knowledge from fungal biology and ecology into the framework of movement ecology can inspire both theoretical and empirical developments, eventually leading towards a better understanding of fungal ecology and community assembly. Conversely, by a greater focus on movement specificities of filamentous fungi, movement ecology stands to benefit from the challenge to evolve its concepts and terminology towards even greater universality. We show how our concept can be applied for other modular organisms (such as clonal plants and slime molds), and how this can lead towards comparative studies with the relationship between organismal movement and ecosystems in the focus

Rate of environmental change across scales in ecology

The rate of change (RoC) of environmental drivers matters: biotic and abiotic components respond differently when faced with a fast or slow change in their environment. This phenomenon occurs across spatial scales and thus levels of ecological organization. We investigated the RoC of environmental drivers in the ecological literature and examined publication trends across ecological levels, including prevalent types of evidence and drivers. Research interest in environmental driver RoC has increased over time (particularly in the last decade), however, the amount of research and type of studies were not equally distributed across levels of organization and different subfields of ecology use temporal terminology (e.g. 'abrupt' and 'gradual') differently, making it difficult to compare studies. At the level of individual organisms, evidence indicates that responses and underlying mechanisms are different when environmental driver treatments are applied at different rates, thus we propose including a time dimension into reaction norms. There is much less experimental evidence at higher levels of ecological organization (i.e. population, community, ecosystem), although theoretical work at the population level indicates the importance of RoC for evolutionary responses. We identified very few studies at the community and ecosystem levels, although existing evidence indicates that driver RoC is important at these scales and potentially could be particularly important for some processes, such as community stability and cascade effects. We recommend shifting from a categorical (e.g. abruptversusgradual) to a quantitative and continuous (e.g. degrees C/h) RoC framework and explicit reporting of RoC parameters, including magnitude, duration and start and end points to ease cross-scale synthesis and alleviate ambiguity. Understanding how driver RoC affects individuals, populations, communities and ecosystems, and furthermore how these effects can feed back between levels is critical to making improved predictions about ecological responses to global change drivers. The application of a unified quantitative RoC framework for ecological studies investigating environmental driver RoC will both allow cross-scale synthesis to be accomplished more easily and has the potential for the generation of novel hypotheses

Myristate and the ecology of AM fungi: significance, opportunities, applications and challenges

A recent study by Sugiura and coworkers reported the non‐symbiotic growth and spore production of an arbuscular mycorrhizal (AM) fungus, Rhizophagus irregularis, when the fungus received an external supply of certain fatty acids, myristates (C:14). This discovery follows the insight that AM fungi receive fatty acids from their hosts when in symbiosis. If this result holds up and can be repeated under nonsterile conditions and with a broader range of fungi, it has numerous consequences for our understanding of AM fungal ecology, from the level of the fungus, at the plant community level, and to functional consequences in ecosystems. In addition, myristate may open up several avenues from a more applied perspective, including improved fungal culture and supplementation of AM fungi or inoculum in the field. We here map these potential opportunities, and additionally offer thoughts on potential risks of this potentially new technology. Lastly, we discuss the specific research challenges that need to be overcome to come to an understanding of the potential role of myristate in AM ecology

Suitability and safety of L-5-methyltetrahydrofolate as a folate source in infant formula: A randomized-controlled trial

L-5-methyltetrahydrofolate is the predominant folate form in human milk but is currently not approved as a folate source for infant and follow-on formula. We aimed to assess the suitability of L-5-methyltetrahydrofolate as a folate source for infants. Growth and tolerance in healthy term infants fed formulae containing equimolar doses of L-5-methyltetrahydrofolate (10.4 mu g/100 ml, n = 120, intervention group) or folic acid (10.0 mu g/100 ml, n = 120, control group) was assessed in a randomized, double-blind, parallel, controlled trial. A reference group of breastfed infants was followed. Both formulae were well accepted without differences in tolerance or occurrence of adverse events. The most common adverse events were common cold, poor weight gain or growth, rash, eczema, or dry skin and respiratory tract infection. Weight gain (the primary outcome) was equivalent in the two groups (95% CI -2.11;1.68 g/d). In line with this, there was only a small difference in absolute body weight adjusted for birth weight and sex at visit 4 (95% CI -235;135 g). Equivalence was also shown for gain in head circumference but not for recumbent length gain and increase in calorie intake. Given the nature of the test, this does not indicate an actual difference, and adjusted means at visit 4 were not significantly different for any of these parameters. Infants receiving formula containing L-5-methyltetrahydrofolate had lower mean plasma levels of unmetabolized folic acid (intervention: 0.73 nmol/L, control: 1.15 nmol/L, p<0.0001) and higher levels of red cell folate (intervention: 907.0 +/- 192.8 nmol/L, control: 839.4 +/- 142.4 nmol/L, p = 0.0095). We conclude that L-5-methyltetrahydrofolate is suitable for use in infant and follow-on formula, and there are no indications of untoward effects

Myristate and the ecology of AM fungi : significance, opportunities, applications and challenges

A recent study by Sugiura and coworkers reported the nonsymbiotic growth and spore production of an arbuscular mycorrhizal (AM) fungus, Rhizophagus irregularis, when the fungus received an external supply of certain fatty acids, myristates (C:14). This discovery follows the insight that AM fungi receive fatty acids from their hosts when in symbiosis. If this result holds up and can be repeated under nonsterile conditions and with a broader range of fungi, it has numerous consequences for our understanding of AM fungal ecology, from the level of the fungus, at the plant community level, and to functional consequences in ecosystems. In addition, myristate may open up several avenues from a more applied perspective, including improved fungal culture and supplementation of AM fungi or inoculum in the field. We here map these potential opportunities, and additionally offer thoughts on potential risks of this potentially new technology. Lastly, we discuss the specific research challenges that need to be overcome to come to an understanding of the potential role of myristate in AM ecology

A Nuclei-Based Conceptual Model of (Eco)evolutionary Dynamics in Fungal Heterokaryons

Filamentous fungi are characterised by specific features, such as multinuclearity, coexistence of genetically different nuclei and nuclear movement across the mycelial network. These attributes make them an interesting, yet rather underappreciated, system for studying (eco)evolutionary dynamics. This is especially noticeable among theoretical studies, where rather few consider nuclei and their role in (eco)evolutionary dynamics. To encourage such theoretical approaches, we here provide an overview of existing research on nuclear genotype heterogeneity (NGH) and its sources, such as mutations and vegetative non-self-fusion. We then discuss the resulting intra-mycelial nuclear dynamics and the potential consequences for fitness and adaptation. Finally, we formulate a nuclei-based conceptual framework, which considers three levels of selection: a single nucleus, a subpopulation of nuclei and the mycelium. We compare this framework to other concepts, for example those that consider only the mycelium as the level of selection, and outline the benefits of our approach for studying (eco)evolutionary dynamics. Our concept should serve as a baseline for modelling approaches, such as individual-based simulations, which will contribute greatly to our understanding of multilevel selection and (eco)evolutionary dynamics in filamentous fungi

Evolution von Ausbreitungsstrategien: Die Fitnesskonsequenzen des Zeitpunkts von Emigration

Dispersal is a life-history trait affecting dynamics and persistence of populations; it evolves under various known selective pressures. Theoretical studies on dispersal typically assume 'natal dispersal', where individuals emigrate right after birth. But emigration may also occur during a later moment within a reproductive season ('breeding dispersal'). For example, some female butterflies first deposit eggs in their natal patch before migrating to other site(s) to continue egg-laying there. How breeding compared to natal dispersal influences the evolution of dispersal has not been explored. To close this gap we used an individual-based simulation approach to analyze (i) the evolution of timing of breeding dispersal in annual organisms, (ii) its influence on dispersal (compared to natal dispersal). Furthermore, we tested (iii) its performance in direct evolutionary contest with individuals following a natal dispersal strategy. Our results show that evolution should typically result in lower dispersal under breeding dispersal, especially when costs of dispersal are low and population size is small. By distributing offspring evenly across two patches, breeding dispersal allows reducing direct sibling competition in the next generation whereas natal dispersal can only reduce trans-generational kin competition by producing highly dispersive offspring in each generation. The added benefit of breeding dispersal is most prominent in patches with small population sizes. Finally, the evolutionary contests show that a breeding dispersal strategy would universally out-compete natal dispersal.Emigration und die daraus resultierende Ausbreitung („dispersal“) ist ein wichtiges Ereignis im Lebenszyklus von Insekten, mit grundlegenden öko-evolutionären Folgen. Fortschreitender globaler Wandel hinterlässt viele Arten in stark fragmentierten Habitaten; der Verbreitungsstrategie kommt deshalb eine Schlüsselrolle im Fortbestehen von Populationen zu. Insekten sind besonders anfällig gegenüber Habitatzerstörungen, da viele von ihnen Spezialisten sind und daher z.B. stark von Präsenz bestimmter Wirtsarten und deren Verteilung abhängen. Zum Schutz dieser Arten ist es folglich entscheidend die Ursachen und Folgen verschiedener Ausbreitungsstrategien zu verstehen. Zudem können Arten mit unterschiedlichen Lebenszyklen spezifische Ausbreitungsstrategien aufweisen. Natale Emigration („natal dispersal“) ist definiert als das Verlassen des Ortes der Geburt, um an einem neuen Ort zu reproduzieren, während „breeding dispersal“ Ausbreitung zwischen zwei aufeinanderfolgenden Paarungen bedeutet. Natal dispersal kann während des Larval- und Adultstadiums stattfinden, breeding dispersal nur während des Adultstadiums. Weiterhin ist der Zeitpunkt der Verpaarung, entweder vor oder nach Ausbreitung, besonders wichtig für Weibchen, die nicht nur die eigenen Gene transportieren, sondern eventuell auch die eines verpaarten Männchens. Es ist eindeutig, dass sich Genfluss und ökoevolutionäre Dynamik zwischen diesen Ausbreitungsstrategien unterscheiden. Schließlich erhielt nformationsverarbeitung durch Insekten und dessen Rolle in emigrationsbezogenen Entscheidungen in jüngster Zeit viel Aufmerksamkeit. Dennoch wurde der Zeitraum der Informationsbeschaffung (z.B. während des Larven- oder Adultstadiums) und folglich die Verfügbarkeit von Information zum Zeitpunkt der Emigration von Theoretikern und Empirikern größtenteils nicht beachtet. Meine Doktorarbeit liefert theoretische Einsichten in den optimalen Zeitpunkt der Emigration, des Zeitpunktes der Paarung (in Relation zu Emigration) und die Rolle von Informationsbeschaffung in Insekten- Metapopulationen. Mit Individuen basierten Modellen analysierte ich zuerst die Evolution des Emigrationszeitpunktes in Metapopulationen, gefolgt von der Evolution des (optimalen) Emigrations- und Paarungszeitpunktes in Metapopulationen von Insekten. Abschließend untersuchte ich, wie sich die Investition von Zeit in das Sammeln von Informationen auf den Zeitpunkt und die Häufigkeit von Emigration auswirkt. Ergebnisse meiner Thesis zeigen, dass die Vermeidung von Konkurrenz innerhalb der Art eine entscheidende Rolle in der Evolution des Zeitpunktes der Emigration einnimmt; weiterhin konnte ich zeigen, dass Insekten Informationen über die Populationsdichte nutzen können, um daran angepasst Entscheidungen bezüglich ihrer Emigration zu treffen; in heterogener Umwelt bestimmt die Toleranz gegenüber der Habitate die Evolution der Ausbreitungsstrategie und des Paarungszeitpunktes, was folglich die lokal Anpassung innerhalb ganzer Landschaften bestimmt. Meine Thesis bietet neue Einsichten in die Evolution von Ausbreitung, insbesondere auf den richtigen Zeitpunkt und die Reihenfolge von Emigration, Verpaarung und dem Sammeln von Informationen. Dieser Aspekt des Timings wurde bisher von theoretischen und empirischen Ökologen größtenteils ignoriert. Um die Populationsdynamik und die Ausbreitung einer Art verstehen zu können, ist es essentiell den Lebenszyklus und die Zeitpunkte der wichtigsten Lebensereignisse (Verbreitung, Reproduktion) zu kennen. Dies ist zwingend nötig, wenn eine erfolgreiche Umsetzung von Naturschutzmaßnahmen (z.B. Wiedereinführung von Arten) oder biologischer Schädlingsbekämpfung (z.B. Einführung von Prädatoren zur Bekämpfung von Schädlingen) angestrebt wird

Dispersal timing: Emigration of insects living in patchy environments

Dispersal is a life-history trait affecting dynamics and persistence of populations; it evolves under various known selective pressures. Theoretical studies on dispersal typically assume 'natal dispersal', where individuals emigrate right after birth. But emigration may also occur during a later moment within a reproductive season ('breeding dispersal'). For example, some female butterflies first deposit eggs in their natal patch before migrating to other site(s) to continue egg-laying there. How breeding compared to natal dispersal influences the evolution of dispersal has not been explored. To close this gap we used an individual-based simulation approach to analyze (i) the evolution of timing of breeding dispersal in annual organisms, (ii) its influence on dispersal (compared to natal dispersal). Furthermore, we tested (iii) its performance in direct evolutionary contest with individuals following a natal dispersal strategy. Our results show that evolution should typically result in lower dispersal under breeding dispersal, especially when costs of dispersal are low and population size is small. By distributing offspring evenly across two patches, breeding dispersal allows reducing direct sibling competition in the next generation whereas natal dispersal can only reduce trans-generational kin competition by producing highly dispersive offspring in each generation. The added benefit of breeding dispersal is most prominent in patches with small population sizes. Finally, the evolutionary contests show that a breeding dispersal strategy would universally out-compete natal dispersal

Data from: Mating timing, dispersal and local adaptation in patchy environments

Dispersal is a life-history trait that can evolve under various known selective pressures as identified by a multitude of theoretical and empirical studies. Yet only few of them are considering the succession of mating and dispersal. The sequence of these events influences gene flow and consequently affects the dynamics and evolution of populations. We use individual-based simulations to investigate the evolution of the timing of dispersal and mating, i.e. mating before or after dispersal. We assume a discrete insect meta-population in a heterogeneous environment, where populations may adapt to local conditions and only females are allowed to disperse. We run the model assuming different levels of species habitat tolerance, carrying capacity, and temporal environmental variability. Our results show that in species with narrow habitat tolerance low to moderate dispersal evolves in combination with mating after dispersal (post-dispersal mating). With such a strategy dispersing females benefit from mating with a resident male, as their offspring will be better adapted to the local habitat conditions. On the contrary, in species with wide habitat tolerance higher dispersal rates in combination with pre-dispersal mating evolves. In this case individuals are adapted to the 'average' habitat where pre-dispersal mating conveys the benefit of carrying relatives' genes into a new population. With high dispersal rates and large population size, local adaptation and kin-structure both vanish and the temporal sequence of dispersal and mating may become a (nearly) neutral trait

MatingTiming_LazarusCode_Replace

We are submitting the code for individual based model simulations, written in Lazarus 1.6