Molecular techniques have revealed striking variation among bird species in the rates of extra–pair paternity (EPP) and intraspecific brood parasitism (IBP). In terms of the proportion of broods affected, rates of EPP and IBP vary across species from 0–95% and 0–50%, respectively. Despite a plethora of hypotheses and several careful comparative analyses, few robust correlates of this interspecific variation have been identified. One explanation for this shortfall is that most comparative studies have tended to focus on contemporary ecological factors and ignored fundamental differences in reproductive biology that evolved millions of years ago. We show that, for both EPP and IBP, over 50% of interspecific variation is due to differences among taxonomic families and orders. Therefore, we test hypotheses that predict interspecific variation in the rate of alternative reproductive strategies should be associated with differences in life history and the form of parental care. Our analyses largely support these predictions, with high rates of reproductive cheating being associated with ‘fast’ life histories. High EPP rates are associated with high rates of adult mortality and reduced paternal care. High IBP rates are associated with high–fecundity rates. These patterns remain intact whether we use species as independent data points or evolutionary contrasts based on either molecular or morphological phylogenies. These results are interpreted as supporting the idea that alternative reproductive strategies are most common in taxa in which the risks of retaliation are low. We suggest a hierarchical explanation for interspecific variation in the incidence of alternative reproductive strategies. Variation between major avian lineages in the EPP and IBP rates are determined by fundamental differences in life history and parental care that evolved many millions of years ago. Variation between populations or individuals of the same species, however, are more likely to be determined by differences in contemporary ecological and genetic factors.
{"title":"Extra-pair paternity and egg dumping in birds: life history, parental care and the risk of retaliation","authors":"K. Arnold, I. P. Owens","doi":"10.1098/rspb.2002.2013","DOIUrl":"https://doi.org/10.1098/rspb.2002.2013","url":null,"abstract":"Molecular techniques have revealed striking variation among bird species in the rates of extra–pair paternity (EPP) and intraspecific brood parasitism (IBP). In terms of the proportion of broods affected, rates of EPP and IBP vary across species from 0–95% and 0–50%, respectively. Despite a plethora of hypotheses and several careful comparative analyses, few robust correlates of this interspecific variation have been identified. One explanation for this shortfall is that most comparative studies have tended to focus on contemporary ecological factors and ignored fundamental differences in reproductive biology that evolved millions of years ago. We show that, for both EPP and IBP, over 50% of interspecific variation is due to differences among taxonomic families and orders. Therefore, we test hypotheses that predict interspecific variation in the rate of alternative reproductive strategies should be associated with differences in life history and the form of parental care. Our analyses largely support these predictions, with high rates of reproductive cheating being associated with ‘fast’ life histories. High EPP rates are associated with high rates of adult mortality and reduced paternal care. High IBP rates are associated with high–fecundity rates. These patterns remain intact whether we use species as independent data points or evolutionary contrasts based on either molecular or morphological phylogenies. These results are interpreted as supporting the idea that alternative reproductive strategies are most common in taxa in which the risks of retaliation are low. We suggest a hierarchical explanation for interspecific variation in the incidence of alternative reproductive strategies. Variation between major avian lineages in the EPP and IBP rates are determined by fundamental differences in life history and parental care that evolved many millions of years ago. Variation between populations or individuals of the same species, however, are more likely to be determined by differences in contemporary ecological and genetic factors.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89969439","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}
L. M. Marquez, M. V. Oppen, B. Willis, David J. Miller
High cross–fertilization rates in vitro and non–monophyletic patterns in molecular phylogenies challenge the taxonomic status of species in the coral genus Acropora. We present data from eight polymorphic allozyme loci that indicate small, but significant, differentiation between sympatric populations of Acropora cytherea and Acropora hyacinthus (FST = 0.025−0.068, p < 0.05), a pair of acroporid corals with very high interspecific fertilization rates in vitro. Although no fixed allelic differences were found between these species, the absence of genetic differentiation between widely allopatric populations suggests that allele frequency differences between A. cytherea and A. hyacinthus in sympatry are biologically significant. By contrast, populations of Acropora tenuis, a species which spawns 2–3 hours earlier and shows low cross–fertilization rates with congeners in vitro, were clearly distinct from A. cytherea and A. hyacinthus (FST = 0.427−0.465, p < 0.05). Moreover, allopatric populations of A. tenuis differed significantly, possibly as a consequence of its relatively short period of larval competency. Our results effectively rule out the possibility that A. hyacinthus and A. cytherea are morphotypes within a single species, and indicate that hybridization occurs relatively infrequently between these taxa in nature.
{"title":"Sympatric populations of the highly cross-fertile coral species Acropora hyacinthus and Acropora cytherea are genetically distinct","authors":"L. M. Marquez, M. V. Oppen, B. Willis, David J. Miller","doi":"10.1098/rspb.2002.2014","DOIUrl":"https://doi.org/10.1098/rspb.2002.2014","url":null,"abstract":"High cross–fertilization rates in vitro and non–monophyletic patterns in molecular phylogenies challenge the taxonomic status of species in the coral genus Acropora. We present data from eight polymorphic allozyme loci that indicate small, but significant, differentiation between sympatric populations of Acropora cytherea and Acropora hyacinthus (FST = 0.025−0.068, p < 0.05), a pair of acroporid corals with very high interspecific fertilization rates in vitro. Although no fixed allelic differences were found between these species, the absence of genetic differentiation between widely allopatric populations suggests that allele frequency differences between A. cytherea and A. hyacinthus in sympatry are biologically significant. By contrast, populations of Acropora tenuis, a species which spawns 2–3 hours earlier and shows low cross–fertilization rates with congeners in vitro, were clearly distinct from A. cytherea and A. hyacinthus (FST = 0.427−0.465, p < 0.05). Moreover, allopatric populations of A. tenuis differed significantly, possibly as a consequence of its relatively short period of larval competency. Our results effectively rule out the possibility that A. hyacinthus and A. cytherea are morphotypes within a single species, and indicate that hybridization occurs relatively infrequently between these taxa in nature.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76728208","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}
Models of malaria epidemiology and evolution are frequently based on the assumption that vector–parasitic associations are benign. Implicit in this assumption is the supposition that all Plasmodium parasites have an equal and neutral effect on vector survival, and thus that there is no parasite genetic variation for vector virulence. While some data support the assumption of avirulence, there has been no examination of the impact of parasite genetic diversity. We conducted a laboratory study with the rodent malaria parasite, Plasmodium chabaudi and the vector, Anopheles stephensi, to determine whether mosquito mortality varied with parasite genotype (CR and ER clones), infection diversity (single versus mixed genotype) and nutrient availability. Vector mortality varied significantly between parasite genotypes, but the rank order of virulence depended on environmental conditions. In standard conditions, mixed genotype infections were the most virulent but when glucose water was limited, mortality was highest in mosquitoes infected with CR. These genotype–by–environment interactions were repeatable across two experiments and could not be explained by variation in anaemia, gametocytaemia, blood meal size, mosquito body size, infection rate or oocyst burden. Variation in the genetic and environmental determinants of virulence may explain conflicting accounts of Plasmodium pathogenicity to mosquitoes in the malaria literature.
{"title":"Genetic and environmental determinants of malaria parasite virulence in mosquitoes","authors":"Heather M. Ferguson, Andrew F. Read","doi":"10.1098/rspb.2002.2023","DOIUrl":"https://doi.org/10.1098/rspb.2002.2023","url":null,"abstract":"Models of malaria epidemiology and evolution are frequently based on the assumption that vector–parasitic associations are benign. Implicit in this assumption is the supposition that all Plasmodium parasites have an equal and neutral effect on vector survival, and thus that there is no parasite genetic variation for vector virulence. While some data support the assumption of avirulence, there has been no examination of the impact of parasite genetic diversity. We conducted a laboratory study with the rodent malaria parasite, Plasmodium chabaudi and the vector, Anopheles stephensi, to determine whether mosquito mortality varied with parasite genotype (CR and ER clones), infection diversity (single versus mixed genotype) and nutrient availability. Vector mortality varied significantly between parasite genotypes, but the rank order of virulence depended on environmental conditions. In standard conditions, mixed genotype infections were the most virulent but when glucose water was limited, mortality was highest in mosquitoes infected with CR. These genotype–by–environment interactions were repeatable across two experiments and could not be explained by variation in anaemia, gametocytaemia, blood meal size, mosquito body size, infection rate or oocyst burden. Variation in the genetic and environmental determinants of virulence may explain conflicting accounts of Plasmodium pathogenicity to mosquitoes in the malaria literature.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82944238","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}
Luis F. Aguirre, A. Herrel, R. V. Damme, Erik Matthysen
The exceptional diversity of neotropical bat communities is sustained by an intricate partitioning of available resources among the member species. Trophical specialization is considered an important evolutionary avenue towards niche partitioning in neotropical phyllostomid bats. From an ancestral insectivorous condition, phyllostomids evolved into highly specialized frugivorous, carnivorous, nectarivorous, piscivorous and even sanguivorous species. Previously, correlations between cranial morphology and trophic ecology within this group have been documented. Here, we examine the evolutionary relationships between bite force and head shape in over 20 species of bats from a single tropical savannah bat community. The results show that bite force increases exponentially with body size across all species examined. Despite the significant differences between large dietary groups using traditional analysis (i.e. non–phylogenetic) and the strong evolutionary correlations between body mass and bite force, phylogenetic analyses indicated no differences in bite performance between insectivorous, omnivorous and frugivorous bats. Comparisons of three species with highly specialized feeding habits (nectarivory, piscivory and sanguivory) with the rest of the species in the community indicate that specialization into these niches comes at the expense of bite performance and, hence, may result in a reduction of the trophic niche breadth.
{"title":"Ecomorphological analysis of trophic niche partitioning in a tropical savannah bat community","authors":"Luis F. Aguirre, A. Herrel, R. V. Damme, Erik Matthysen","doi":"10.1098/rspb.2002.2011","DOIUrl":"https://doi.org/10.1098/rspb.2002.2011","url":null,"abstract":"The exceptional diversity of neotropical bat communities is sustained by an intricate partitioning of available resources among the member species. Trophical specialization is considered an important evolutionary avenue towards niche partitioning in neotropical phyllostomid bats. From an ancestral insectivorous condition, phyllostomids evolved into highly specialized frugivorous, carnivorous, nectarivorous, piscivorous and even sanguivorous species. Previously, correlations between cranial morphology and trophic ecology within this group have been documented. Here, we examine the evolutionary relationships between bite force and head shape in over 20 species of bats from a single tropical savannah bat community. The results show that bite force increases exponentially with body size across all species examined. Despite the significant differences between large dietary groups using traditional analysis (i.e. non–phylogenetic) and the strong evolutionary correlations between body mass and bite force, phylogenetic analyses indicated no differences in bite performance between insectivorous, omnivorous and frugivorous bats. Comparisons of three species with highly specialized feeding habits (nectarivory, piscivory and sanguivory) with the rest of the species in the community indicate that specialization into these niches comes at the expense of bite performance and, hence, may result in a reduction of the trophic niche breadth.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83532949","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}
N. Pike, D. Richard, W. Foster, Lakshminarayanan Mahadevan
Insects provide examples of many cunning stratagems to cope with the challenges of living in a world dominated by surface forces. Despite being the current masters of the land environment, they are at constant risk of being entrapped in liquids, which they prevent by having waxy and hairy surfaces. The problem is particularly acute in an enclosed space, such as a plant gall. Using secreted wax to efficiently parcel and transport their own excrement, aphids were able to solve this problem 200 Myr ago. Here, we report on the physical and physiological significance of this ingenious solution. The secreted powdery wax has three distinct roles: (i) it is hydrophobic, (ii) it creates a microscopically rough inner gall surface made of weakly compacted wax needles making the gall ultra–hydrophobic, and (iii) it coats the honeydew droplets converting them into liquid marbles, that can be rapidly and efficiently moved.
{"title":"How aphids lose their marbles","authors":"N. Pike, D. Richard, W. Foster, Lakshminarayanan Mahadevan","doi":"10.1098/rspb.2002.1999","DOIUrl":"https://doi.org/10.1098/rspb.2002.1999","url":null,"abstract":"Insects provide examples of many cunning stratagems to cope with the challenges of living in a world dominated by surface forces. Despite being the current masters of the land environment, they are at constant risk of being entrapped in liquids, which they prevent by having waxy and hairy surfaces. The problem is particularly acute in an enclosed space, such as a plant gall. Using secreted wax to efficiently parcel and transport their own excrement, aphids were able to solve this problem 200 Myr ago. Here, we report on the physical and physiological significance of this ingenious solution. The secreted powdery wax has three distinct roles: (i) it is hydrophobic, (ii) it creates a microscopically rough inner gall surface made of weakly compacted wax needles making the gall ultra–hydrophobic, and (iii) it coats the honeydew droplets converting them into liquid marbles, that can be rapidly and efficiently moved.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74518042","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}
M. Sutton, D. Briggs, D. Siveter, D. Siveter, P. Orr
The small, non–biomineralized, three–dimensionally preserved arthropod Offacolus kingi Orr et al. from the Wenlock Series (Silurian) of Herefordshire, England, is re–evaluated, and the new family Offacolidae erected. This new study is based on specimens which have been serially ground, reconstructed by computer and rendered in the round as coloured models. Offacolus possesses a prosomal appendage array similar to that of Limulus, but also bears robust and setose exopods on appendages II–V which are unlike those found in any other arthropods. Opisthosomal appendages are similar in number and morphology to the book–gills of Limulus. Cladistic analysis places Offacolus basally within the Chelicerata, as a sister taxon to the eurypterids and extant chelicerates, but more derived than the Devonian Weinbergina.
{"title":"The arthropod Offacolus kingi (Chelicerata) from the Silurian of Herefordshire, England: computer based morphological reconstructions and phylogenetic affinities","authors":"M. Sutton, D. Briggs, D. Siveter, D. Siveter, P. Orr","doi":"10.1098/rspb.2002.1986","DOIUrl":"https://doi.org/10.1098/rspb.2002.1986","url":null,"abstract":"The small, non–biomineralized, three–dimensionally preserved arthropod Offacolus kingi Orr et al. from the Wenlock Series (Silurian) of Herefordshire, England, is re–evaluated, and the new family Offacolidae erected. This new study is based on specimens which have been serially ground, reconstructed by computer and rendered in the round as coloured models. Offacolus possesses a prosomal appendage array similar to that of Limulus, but also bears robust and setose exopods on appendages II–V which are unlike those found in any other arthropods. Opisthosomal appendages are similar in number and morphology to the book–gills of Limulus. Cladistic analysis places Offacolus basally within the Chelicerata, as a sister taxon to the eurypterids and extant chelicerates, but more derived than the Devonian Weinbergina.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75757044","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 robust macro–ecological observation that there are more small–bodied species implies that smallbodied organisms have experienced elevated net rates of diversification. We investigate the role of body size in creating non–random differences in rates of cladogenesis using a set of 38 species–level phylogenies drawn from a range of animal groups. We use independent contrasts to explore the relationship between body size and species richness within individual phylogenies and across related sets of phylogenies. We also carry out a meta–analysis looking for associations between body size and species richness across the taxa. We find little evidence for increased cladogenesis among small–bodied organisms within taxa, and no evidence for any consistent differences between taxa. We explore possible explanations for the inconsistency of our findings with macro–ecological patterns.
{"title":"Are most species small? Not within species–level phylogenies","authors":"C. David, L. Orme, N. Isaac, A. Purvis","doi":"10.1098/rspb.2002.2003","DOIUrl":"https://doi.org/10.1098/rspb.2002.2003","url":null,"abstract":"The robust macro–ecological observation that there are more small–bodied species implies that smallbodied organisms have experienced elevated net rates of diversification. We investigate the role of body size in creating non–random differences in rates of cladogenesis using a set of 38 species–level phylogenies drawn from a range of animal groups. We use independent contrasts to explore the relationship between body size and species richness within individual phylogenies and across related sets of phylogenies. We also carry out a meta–analysis looking for associations between body size and species richness across the taxa. We find little evidence for increased cladogenesis among small–bodied organisms within taxa, and no evidence for any consistent differences between taxa. We explore possible explanations for the inconsistency of our findings with macro–ecological patterns.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78037087","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}
In facultative polygynous birds with biparental care, a trade–off may occur between male parental care and attraction of additional mates. If there is a cost associated with reduced male parental care, the relative benefit of mate attraction may be predicted to decrease as the size of a male's clutch or brood increases. We tested this prediction in monogamous pairs of facultatively polygynous European starlings (Sturnus vulgaris). The larger the clutch, the more time the male spent incubating and the less time he spent attracting an additional female (i.e. singing near and carrying green nesting material into adjacent empty nest–boxes). Reduced paternal incubation resulted in lower overall incubation (the female did not compensate) and lower hatching success. Immediately after experimental reduction of clutches, males spent significantly less time incubating and more time singing and carrying greenery, and vice versa for experimentally enlarged clutches. Males with experimentally reduced clutches attracted a second female more often than males with experimentally enlarged clutches. This is the first study, to our knowledge, to provide experimental evidence for an adjustment of paternal care and male mate–attraction effort to clutch size. However, a trade–off between paternal nestling provisioning and mate attraction was not revealed, probably due to the absence of unpaired females by that time in the breeding season. Experiments showed that the relative contribution of the male and female to nestling provisioning was unrelated to brood size.
{"title":"Paternal care and male mate–attraction effort in the European starling is adjusted to clutch size","authors":"J. Komdeur, P. Wiersma, M. Magrath","doi":"10.1098/rspb.2002.1987","DOIUrl":"https://doi.org/10.1098/rspb.2002.1987","url":null,"abstract":"In facultative polygynous birds with biparental care, a trade–off may occur between male parental care and attraction of additional mates. If there is a cost associated with reduced male parental care, the relative benefit of mate attraction may be predicted to decrease as the size of a male's clutch or brood increases. We tested this prediction in monogamous pairs of facultatively polygynous European starlings (Sturnus vulgaris). The larger the clutch, the more time the male spent incubating and the less time he spent attracting an additional female (i.e. singing near and carrying green nesting material into adjacent empty nest–boxes). Reduced paternal incubation resulted in lower overall incubation (the female did not compensate) and lower hatching success. Immediately after experimental reduction of clutches, males spent significantly less time incubating and more time singing and carrying greenery, and vice versa for experimentally enlarged clutches. Males with experimentally reduced clutches attracted a second female more often than males with experimentally enlarged clutches. This is the first study, to our knowledge, to provide experimental evidence for an adjustment of paternal care and male mate–attraction effort to clutch size. However, a trade–off between paternal nestling provisioning and mate attraction was not revealed, probably due to the absence of unpaired females by that time in the breeding season. Experiments showed that the relative contribution of the male and female to nestling provisioning was unrelated to brood size.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74231642","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}
Although recent evidence indicates that coevolutionary interactions between species often vary on a biogeographical scale, little consideration has been given to the processes responsible for producing this pattern. One potential explanation is that changes in the community composition alter the coevolutionary interactions between species, but little evidence exists regarding the occurrence of such changes. Here we present evidence that the pattern of natural selection on plant defence traits, and the probable response to that selection, are critically dependent on the composition of the biotic community. The evolutionary trajectory of defence traits against mammalian herbivory in the Ivyleaf morning glory (Ipomoea hederacea), and which defence traits are likely to respond to selection, are both dependent on the presence or absence of insect herbivores. These results indicate that variation in community composition may be a driving force in generating geographical mosaics.
{"title":"The evolution of tolerance to deer herbivory: modifications caused by the abundance of insect herbivores","authors":"J. Stinchcombe, M. Rausher","doi":"10.1098/rspb.2002.2015","DOIUrl":"https://doi.org/10.1098/rspb.2002.2015","url":null,"abstract":"Although recent evidence indicates that coevolutionary interactions between species often vary on a biogeographical scale, little consideration has been given to the processes responsible for producing this pattern. One potential explanation is that changes in the community composition alter the coevolutionary interactions between species, but little evidence exists regarding the occurrence of such changes. Here we present evidence that the pattern of natural selection on plant defence traits, and the probable response to that selection, are critically dependent on the composition of the biotic community. The evolutionary trajectory of defence traits against mammalian herbivory in the Ivyleaf morning glory (Ipomoea hederacea), and which defence traits are likely to respond to selection, are both dependent on the presence or absence of insect herbivores. These results indicate that variation in community composition may be a driving force in generating geographical mosaics.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72894794","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 eyespots on the ventral wings of Bicyclus anynana butterflies are exposed when at rest and interact with predators. Those on the dorsal surface are not exposed in this way, and may be involved in courtship and mate choice. In this study, we examined whether the size and fluctuating asymmetry (FA) of dorsal eyespots are reliable signals of male quality. High developmental stability is considered to result in low FA, and to be associated with high quality. Individuals of high quality are predicted to produce sexually selected traits that are large and symmetrical, at a relatively low cost. In this study, we manipulated eyespot development to uncouple eyespot size and FA in order to examine their independent roles in signalling to the female. Individual females in cages were given the choice between two or three males differing in eyespot traits. The results indicate that although size per se of the eyespots is used as a signal, FA and wing size are not. We discuss the use of FA in studies of sexual selection and aspects of sexual selection on dorsal eyespot size.
{"title":"Female choice depends on size but not symmetry of dorsal eyespots in the butterfly Bicyclus anynana","authors":"C. J. Breuker, P. Brakefield","doi":"10.1098/rspb.2002.2005","DOIUrl":"https://doi.org/10.1098/rspb.2002.2005","url":null,"abstract":"The eyespots on the ventral wings of Bicyclus anynana butterflies are exposed when at rest and interact with predators. Those on the dorsal surface are not exposed in this way, and may be involved in courtship and mate choice. In this study, we examined whether the size and fluctuating asymmetry (FA) of dorsal eyespots are reliable signals of male quality. High developmental stability is considered to result in low FA, and to be associated with high quality. Individuals of high quality are predicted to produce sexually selected traits that are large and symmetrical, at a relatively low cost. In this study, we manipulated eyespot development to uncouple eyespot size and FA in order to examine their independent roles in signalling to the female. Individual females in cages were given the choice between two or three males differing in eyespot traits. The results indicate that although size per se of the eyespots is used as a signal, FA and wing size are not. We discuss the use of FA in studies of sexual selection and aspects of sexual selection on dorsal eyespot size.","PeriodicalId":20585,"journal":{"name":"Proceedings of the Royal Society of London. Series B. Biological Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2002-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73263992","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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