The enthalpy balance model of growth uses measurements of the rates of heat and CO2 production to quantify rates of decarboxylation, oxidative phosphorylation and net anabolism. Enthalpy conversion efficiency (ηH) and the net rate of conservation of enthalpy in reduced biosynthetic products (RSGΔHB) can be calculated from metabolic heat rate (q) and CO2 rate (RCO2). ηH is closely related to carbon conversion efficiency and the efficiency of conservation of available electrons in biosynthetic products. RSGΔHB and η can be used, together with biomass composition, to describe the rate and efficiency of growth of plant tissues. q is directly related to the rate of O2 consumption and the ratio q:RCO2 is inversely related to the respiratory quotient. We grew seedlings of Eucalyptus globulus at 16 and 28°C for four to six weeks, then measured q and RCO2 using isothermal calorimetry. Respiratory rate at a given temperature was increased by a lower growth temperature but ηH was unaffected. Enthalpy conversion efficiency—and, therefore, carbon conversion efficiency—decreased with increasing temperature from 15 to 35°C. The ratio of oxidative phosphorylation to oxygen consumption (P/O ratio) was inferred in vivo from ηH and by assuming a constant ratio of growth to maintenance respiration with changing temperature. The P/O ratio decreased from 2.1 at 10-15°C to less than 0.3 at 35°C, suggesting that decreased efficiency was not only due to activity of the alternative oxidase pathway. In agreement with predictions from non-equilibrium thermodynamics, growth rate was maximal near 25°C, where the calculated P/O ratio was about half maximum. We propose that less efficient pathways, such as the alternative oxidase pathway, are necessary to satisfy the condition of conductance matching whilst maintaining a near constant phosphorylation potential. These conditions minimize entropy production and maximize the efficiency of mitochondrial energy conversions as growing conditions change, while maintaining adequate finite rates of energy processing.
{"title":"Application of an enthalpy balance model of the relation between growth and respiration to temperature acclimation of Eucalyptus globulus seedlings","authors":"C. Macfarlane, M. Adams, L. Hansen","doi":"10.1098/rspb.2002.2030","DOIUrl":"https://doi.org/10.1098/rspb.2002.2030","url":null,"abstract":"The enthalpy balance model of growth uses measurements of the rates of heat and CO2 production to quantify rates of decarboxylation, oxidative phosphorylation and net anabolism. Enthalpy conversion efficiency (ηH) and the net rate of conservation of enthalpy in reduced biosynthetic products (RSGΔHB) can be calculated from metabolic heat rate (q) and CO2 rate (RCO2). ηH is closely related to carbon conversion efficiency and the efficiency of conservation of available electrons in biosynthetic products. RSGΔHB and η can be used, together with biomass composition, to describe the rate and efficiency of growth of plant tissues. q is directly related to the rate of O2 consumption and the ratio q:RCO2 is inversely related to the respiratory quotient. We grew seedlings of Eucalyptus globulus at 16 and 28°C for four to six weeks, then measured q and RCO2 using isothermal calorimetry. Respiratory rate at a given temperature was increased by a lower growth temperature but ηH was unaffected. Enthalpy conversion efficiency—and, therefore, carbon conversion efficiency—decreased with increasing temperature from 15 to 35°C. The ratio of oxidative phosphorylation to oxygen consumption (P/O ratio) was inferred in vivo from ηH and by assuming a constant ratio of growth to maintenance respiration with changing temperature. The P/O ratio decreased from 2.1 at 10-15°C to less than 0.3 at 35°C, suggesting that decreased efficiency was not only due to activity of the alternative oxidase pathway. In agreement with predictions from non-equilibrium thermodynamics, growth rate was maximal near 25°C, where the calculated P/O ratio was about half maximum. We propose that less efficient pathways, such as the alternative oxidase pathway, are necessary to satisfy the condition of conductance matching whilst maintaining a near constant phosphorylation potential. These conditions minimize entropy production and maximize the efficiency of mitochondrial energy conversions as growing conditions change, while maintaining adequate finite rates of energy processing.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89984088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Despite recent findings that mutualistic interactions between two species may be greatly affected by species external to the mutualism, the implications of such multi–species interactions for the population dynamics of the mutualists are virtually unexplored. In this paper, we ask how the mutualism between the shoot–base boring weevil Apion onopordi and the rust fungus Puccinia punctiformis is influenced by the dynamics of their shared host plant Cirsium arvense, and vice versa. In particular, we hypothesized that the distribution of the weevil's egg load between healthy and rust–infected thistles may regulate the abundance of the mutualists and their host plant. In contrast to our expectations we found that the dynamics of the mutualists are largely determined by the dynamics of their host. This is, to our knowledge, the first demonstration that the dynamics of a mutualism are driven by a third, non–mutualistic species.
{"title":"Dynamics of a mutualism in a multi-species context","authors":"S. Bacher, J. Friedli","doi":"10.1098/rspb.2002.2048","DOIUrl":"https://doi.org/10.1098/rspb.2002.2048","url":null,"abstract":"Despite recent findings that mutualistic interactions between two species may be greatly affected by species external to the mutualism, the implications of such multi–species interactions for the population dynamics of the mutualists are virtually unexplored. In this paper, we ask how the mutualism between the shoot–base boring weevil Apion onopordi and the rust fungus Puccinia punctiformis is influenced by the dynamics of their shared host plant Cirsium arvense, and vice versa. In particular, we hypothesized that the distribution of the weevil's egg load between healthy and rust–infected thistles may regulate the abundance of the mutualists and their host plant. In contrast to our expectations we found that the dynamics of the mutualists are largely determined by the dynamics of their host. This is, to our knowledge, the first demonstration that the dynamics of a mutualism are driven by a third, non–mutualistic species.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73667242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Slagsvold, B. Hansen, L. E. Johannessen, J. Lifjeld
Sexual–selection theories generally assume that mating preferences are heritable traits. However, there is substantial evidence that the rearing environment may be important for the development of mating preferences, indicating that they may be learnt, or modified by experience. The relative importance of such sexual imprinting across species remains largely unexplored. Here, we report results of a large–scale cross–fostering experiment in the wild in which nestling birds were raised by parents of a different species. We show that resulting sexual imprinting may have a negative effect on pairing success in one species (the great tit, Parus major), but not in two other species (the blue tit, P. caeruleus and the pied flycatcher, Ficedula hypoleuca). A remarkable variation thus seems to exist, even between species that are congeneric and have similar breeding ecologies. The cross–fostering resulted in heterospecific pairings between the two tit species (female blue tit breeding with male great tit), which has never, to our knowledge, been previously documented. However, the chicks fledging from these nests were all blue tit.
{"title":"Mate choice and imprinting in birds studied by cross-fostering in the wild","authors":"T. Slagsvold, B. Hansen, L. E. Johannessen, J. Lifjeld","doi":"10.1098/rspb.2002.2045","DOIUrl":"https://doi.org/10.1098/rspb.2002.2045","url":null,"abstract":"Sexual–selection theories generally assume that mating preferences are heritable traits. However, there is substantial evidence that the rearing environment may be important for the development of mating preferences, indicating that they may be learnt, or modified by experience. The relative importance of such sexual imprinting across species remains largely unexplored. Here, we report results of a large–scale cross–fostering experiment in the wild in which nestling birds were raised by parents of a different species. We show that resulting sexual imprinting may have a negative effect on pairing success in one species (the great tit, Parus major), but not in two other species (the blue tit, P. caeruleus and the pied flycatcher, Ficedula hypoleuca). A remarkable variation thus seems to exist, even between species that are congeneric and have similar breeding ecologies. The cross–fostering resulted in heterospecific pairings between the two tit species (female blue tit breeding with male great tit), which has never, to our knowledge, been previously documented. However, the chicks fledging from these nests were all blue tit.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84547079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The evolution of mate choice for genetic benefits has become the tale of two hypotheses: Fisher's ‘run–away’ and ‘good genes’, or viability indicators. These hypotheses are often pitted against each other as alternatives, with evidence that attractive males sire more viable offspring interpreted as support for good genes and with a negative or null relationship between mating success of sons and other components of fitness interpreted as favouring the Fisher process. Here, we build a general model of female choice for indirect benefits that captures the essence of both the ‘Fisherian’ and ‘good–genes’ models. All versions of our model point to a single process that favours female preference for males siring offspring of high reproductive value. Enhanced mating success and survival are therefore equally valid genetic benefits of mate choice, but their relative importance varies depending on female choice costs. The relationship between male attractiveness and survival may be positive or negative, depending on life–history trade–offs and mating skew. This relationship can change sign in response to increased costliness of choice or environmental change. Any form of female preference is subject to self–reinforcing evolution, and any relationship (or lack thereof) between male display and offspring survival is inevitably an indicator of offspring reproductive values. Costly female choice can be maintained with or without higher offspring survival.
{"title":"The sexual selection continuum","authors":"H. Kokko, R. Brooks, J. McNamara, A. Houston","doi":"10.1098/rspb.2002.2020","DOIUrl":"https://doi.org/10.1098/rspb.2002.2020","url":null,"abstract":"The evolution of mate choice for genetic benefits has become the tale of two hypotheses: Fisher's ‘run–away’ and ‘good genes’, or viability indicators. These hypotheses are often pitted against each other as alternatives, with evidence that attractive males sire more viable offspring interpreted as support for good genes and with a negative or null relationship between mating success of sons and other components of fitness interpreted as favouring the Fisher process. Here, we build a general model of female choice for indirect benefits that captures the essence of both the ‘Fisherian’ and ‘good–genes’ models. All versions of our model point to a single process that favours female preference for males siring offspring of high reproductive value. Enhanced mating success and survival are therefore equally valid genetic benefits of mate choice, but their relative importance varies depending on female choice costs. The relationship between male attractiveness and survival may be positive or negative, depending on life–history trade–offs and mating skew. This relationship can change sign in response to increased costliness of choice or environmental change. Any form of female preference is subject to self–reinforcing evolution, and any relationship (or lack thereof) between male display and offspring survival is inevitably an indicator of offspring reproductive values. Costly female choice can be maintained with or without higher offspring survival.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83811722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interspecific interactions can affect population dynamics and the evolution of species traits by altering demographic rates such as reproduction and survival. The influence of mutualism on population processes is thought to depend on both the benefits and costs of the interaction. However, few studies have explicitly quantified both benefits and costs in terms of demographic rates; furthermore there has been little consideration as to how benefits and costs depend on the demographic effects of factors extrinsic to the interaction. I studied how benefits (pollination) and costs (larval fruit consumption) of pollinating seed–consumers (senita moths) affect the reproduction of senita cacti and how these effects may rely on extrinsic water limitation for reproduction. Fruit initiation was not limited by moth pollination, but survival of initiated fruit increased when moth eggs were removed from flowers. Watered cacti produced more flowers and initiated more fruit from hand–pollinated flowers than did unwatered cacti, but fruit initiation remained low despite excess pollen. Even though water, pollination and larvae each affected a component of cactus reproduction, when all of these factors were included in a factorial experiment, pollination and water determined rates of reproduction. Counter–intuitively, larval fruit consumption had a negligible effect on cactus reproduction. By quantifying both benefits and costs of mutualism in terms of demographic rates, this study demonstrates that benefits and costs can be differentially influential to population processes and that interpretation of their influences can depend on demographic effects of factors extrinsic to the interaction.
{"title":"Benefits and costs of mutualism: demographic consequences in a pollinating seed–consumer interaction","authors":"J. N. Holland","doi":"10.1098/rspb.2002.2027","DOIUrl":"https://doi.org/10.1098/rspb.2002.2027","url":null,"abstract":"Interspecific interactions can affect population dynamics and the evolution of species traits by altering demographic rates such as reproduction and survival. The influence of mutualism on population processes is thought to depend on both the benefits and costs of the interaction. However, few studies have explicitly quantified both benefits and costs in terms of demographic rates; furthermore there has been little consideration as to how benefits and costs depend on the demographic effects of factors extrinsic to the interaction. I studied how benefits (pollination) and costs (larval fruit consumption) of pollinating seed–consumers (senita moths) affect the reproduction of senita cacti and how these effects may rely on extrinsic water limitation for reproduction. Fruit initiation was not limited by moth pollination, but survival of initiated fruit increased when moth eggs were removed from flowers. Watered cacti produced more flowers and initiated more fruit from hand–pollinated flowers than did unwatered cacti, but fruit initiation remained low despite excess pollen. Even though water, pollination and larvae each affected a component of cactus reproduction, when all of these factors were included in a factorial experiment, pollination and water determined rates of reproduction. Counter–intuitively, larval fruit consumption had a negligible effect on cactus reproduction. By quantifying both benefits and costs of mutualism in terms of demographic rates, this study demonstrates that benefits and costs can be differentially influential to population processes and that interpretation of their influences can depend on demographic effects of factors extrinsic to the interaction.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87209499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aposematic insects use warning colours to deter predators, but many also produce odours or sounds when attacked by a predator. One possible role for these additional components is that they promote the association between the warning colour and the non–profitability it signals, thus reducing the chance of future attacks from visually hunting predators. This experiment explicitly tests this idea by looking at the effects of sound on a visual discrimination task. Young domestic chicks were trained to look for food rewards under coloured paper cones scattered in an experimental arena. In a subsequent visual discrimination task, they learned to discriminate between rewarded and non–rewarded hats on the basis of colour. Half the chicks performed this task in silence, whilst the other half had a tone played when they attacked non–rewarded hats. The presence of the tone improved the speed of colour discrimination learning. This demonstrates that there could be a selective advantage for aposematic coloured insects to emit sounds when attacked, since avian predators will learn to avoid their coloration more quickly. The role of psychological interactions between signal components in receivers is discussed in relation to the evolution of multimodal displays.
{"title":"Sound improves visual discrimination learning in avian predators","authors":"C. Rowe","doi":"10.1098/rspb.2002.2012","DOIUrl":"https://doi.org/10.1098/rspb.2002.2012","url":null,"abstract":"Aposematic insects use warning colours to deter predators, but many also produce odours or sounds when attacked by a predator. One possible role for these additional components is that they promote the association between the warning colour and the non–profitability it signals, thus reducing the chance of future attacks from visually hunting predators. This experiment explicitly tests this idea by looking at the effects of sound on a visual discrimination task. Young domestic chicks were trained to look for food rewards under coloured paper cones scattered in an experimental arena. In a subsequent visual discrimination task, they learned to discriminate between rewarded and non–rewarded hats on the basis of colour. Half the chicks performed this task in silence, whilst the other half had a tone played when they attacked non–rewarded hats. The presence of the tone improved the speed of colour discrimination learning. This demonstrates that there could be a selective advantage for aposematic coloured insects to emit sounds when attacked, since avian predators will learn to avoid their coloration more quickly. The role of psychological interactions between signal components in receivers is discussed in relation to the evolution of multimodal displays.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90982043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Theory predicts that mate choice can lead to an increase in female fecundity if the secondary sexual traits used by females to assess male quality covary with the number of sperm transferred during copulation. Where females mate multiply, such a relationship between male attractiveness and ejaculate size may, additionally (or alternatively), serve to augment the effect of indirect selection by biasing paternity in favour of preferred males. In either case, a positive correlation between male attractiveness and the size of ejaculates delivered at copulation is predicted. To date, some of the most convincing (indirect) evidence for this prediction comes from the guppy, a species of fish exhibiting a resource–free mating system in which attractive males tend to have larger sperm reserves. We show that, during solicited copulations, male guppies with preferred phenotypes actually transfer more sperm to females than their less–ornamented counterparts, irrespective of the size of their initial sperm stores. Our results also reveal that, during coercive copulations, the relationship between ejaculate size and the male's phenotype breaks down. This latter result, in conjunction with our finding that mating speed—a factor under the female's control—is a significant predictor of ejaculate size, leads us to speculate that females may exert at least partial control over the number of sperm inseminated during cooperative matings.
{"title":"Male phenotype predicts insemination success in guppies","authors":"A. Pilastro, J. Evans, S. Sartorelli, A. Bisazza","doi":"10.1098/rspb.2002.2017","DOIUrl":"https://doi.org/10.1098/rspb.2002.2017","url":null,"abstract":"Theory predicts that mate choice can lead to an increase in female fecundity if the secondary sexual traits used by females to assess male quality covary with the number of sperm transferred during copulation. Where females mate multiply, such a relationship between male attractiveness and ejaculate size may, additionally (or alternatively), serve to augment the effect of indirect selection by biasing paternity in favour of preferred males. In either case, a positive correlation between male attractiveness and the size of ejaculates delivered at copulation is predicted. To date, some of the most convincing (indirect) evidence for this prediction comes from the guppy, a species of fish exhibiting a resource–free mating system in which attractive males tend to have larger sperm reserves. We show that, during solicited copulations, male guppies with preferred phenotypes actually transfer more sperm to females than their less–ornamented counterparts, irrespective of the size of their initial sperm stores. Our results also reveal that, during coercive copulations, the relationship between ejaculate size and the male's phenotype breaks down. This latter result, in conjunction with our finding that mating speed—a factor under the female's control—is a significant predictor of ejaculate size, leads us to speculate that females may exert at least partial control over the number of sperm inseminated during cooperative matings.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83694587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elaborate secondary sexual traits offset the costs that they impose on their bearer by facilitating reproductive benefits, through increased success in intrasexual contests or increased attractiveness to choosy mates. Some traits enhance both strategies. Conversely, I show that spotted bowerbirds Chlamydera maculata may face a trade–off. The trait that best predicts their mating success, numbers of Solanum berries exhibited on a bower, also provokes increased intrasexual aggression in the form of bower destructions by neighbouring bower owners, which reduce the quality of the male's bower. At natural berry numbers, levels of mating success in the population are skewed, but levels of destruction do not vary with berry number. When berry numbers are artificially exaggerated, increased levels of destructions occur, but mating success does not increase. When offered excess berries, either to add to the bower or artificially placed on the bower, bower owners preferred to use numbers of berries related to the number that they displayed naturally. This decision is made without direct experience of the attendant changes in destruction or mating success. This indicates that bower owners may assess their own social standing in relation to their neighbours and modulate their display accordingly.
{"title":"Bower decorations attract females but provoke other male spotted bowerbirds: bower owners resolve this trade-off","authors":"J. Madden","doi":"10.1098/rspb.2002.1988","DOIUrl":"https://doi.org/10.1098/rspb.2002.1988","url":null,"abstract":"Elaborate secondary sexual traits offset the costs that they impose on their bearer by facilitating reproductive benefits, through increased success in intrasexual contests or increased attractiveness to choosy mates. Some traits enhance both strategies. Conversely, I show that spotted bowerbirds Chlamydera maculata may face a trade–off. The trait that best predicts their mating success, numbers of Solanum berries exhibited on a bower, also provokes increased intrasexual aggression in the form of bower destructions by neighbouring bower owners, which reduce the quality of the male's bower. At natural berry numbers, levels of mating success in the population are skewed, but levels of destruction do not vary with berry number. When berry numbers are artificially exaggerated, increased levels of destructions occur, but mating success does not increase. When offered excess berries, either to add to the bower or artificially placed on the bower, bower owners preferred to use numbers of berries related to the number that they displayed naturally. This decision is made without direct experience of the attendant changes in destruction or mating success. This indicates that bower owners may assess their own social standing in relation to their neighbours and modulate their display accordingly.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84749253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Theory predicts that (i) vertical transmission of parasites (i.e. when they are passed directly from a host to its offspring) selects for benign association with the host and that (ii) vertically transmitted parasites that lower their hosts' fitness cannot persist if they are not able to infect horizontally (i.e. contagiously) other host individuals in the population. In this paper, we develop a mathematical model to examine whether mutualism is a prerequisite for persistence of exclusively vertically transmitted (from maternal plant to offspring via seeds) fungal endophytes in structured grass metapopulations. Interestingly, endophyte survival does not require plant mutualism, even in a metapopulation consisting of qualitatively identical patches, if vertical transmission of the fungus is perfect, i.e. if all established seedlings in offspring of the endophyte–infected plant are infected. In more realistic situations, when the metapopulation consists of qualitatively different patches, endophyte–infected plants may persist at the metapopulation level even if the vertical transmission is imperfect (due to hyphae inviability or failure to grow into all seeds) and the endophyte decreases the host grass fitness in certain environments. These results have biological importance because they (i) question the requirement of a mutualistic nature in exclusively vertically transmitted symbionts and (ii) emphasize the importance of habitat diversity in relation to symbiont success in vertical transmission.
{"title":"The persistence of vertically transmitted fungi in grass metapopulations","authors":"K. Saikkonen, D. Ion, M. Gyllenberg","doi":"10.1098/rspb.2002.2006","DOIUrl":"https://doi.org/10.1098/rspb.2002.2006","url":null,"abstract":"Theory predicts that (i) vertical transmission of parasites (i.e. when they are passed directly from a host to its offspring) selects for benign association with the host and that (ii) vertically transmitted parasites that lower their hosts' fitness cannot persist if they are not able to infect horizontally (i.e. contagiously) other host individuals in the population. In this paper, we develop a mathematical model to examine whether mutualism is a prerequisite for persistence of exclusively vertically transmitted (from maternal plant to offspring via seeds) fungal endophytes in structured grass metapopulations. Interestingly, endophyte survival does not require plant mutualism, even in a metapopulation consisting of qualitatively identical patches, if vertical transmission of the fungus is perfect, i.e. if all established seedlings in offspring of the endophyte–infected plant are infected. In more realistic situations, when the metapopulation consists of qualitatively different patches, endophyte–infected plants may persist at the metapopulation level even if the vertical transmission is imperfect (due to hyphae inviability or failure to grow into all seeds) and the endophyte decreases the host grass fitness in certain environments. These results have biological importance because they (i) question the requirement of a mutualistic nature in exclusively vertically transmitted symbionts and (ii) emphasize the importance of habitat diversity in relation to symbiont success in vertical transmission.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84029509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A swarm of honeybees (Apis mellifera) is capable of selecting one nest–site when faced with a choice of several. We adapt classical mathematical models of disease, information and competing beliefs to such decision–making processes. We show that the collective decision may be arrived at without the necessity for any bee to make any comparison between sites.
{"title":"Deciding on a new home: how do honeybees agree?","authors":"N. Britton, N. Franks, S. Pratt, T. Seeley","doi":"10.1098/rspb.2002.2001","DOIUrl":"https://doi.org/10.1098/rspb.2002.2001","url":null,"abstract":"A swarm of honeybees (Apis mellifera) is capable of selecting one nest–site when faced with a choice of several. We adapt classical mathematical models of disease, information and competing beliefs to such decision–making processes. We show that the collective decision may be arrived at without the necessity for any bee to make any comparison between sites.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91548744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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