Environmental alteration for urban development prompts ecological changes across urban centres, r... more Environmental alteration for urban development prompts ecological changes across urban centres, ranging out towards the surrounding undisturbed areas. These impact on organisms living across the urban-rural gradient and insects, being widely distributed in nature, are confronted with adaptive choices in such situations. The temperature in urban cores is generally higher due to the urban heat island effect. Thus, insects might modify their behaviour or morphology to cope with the urban environment. The common wasp Vespula vulgaris (L.) has shown adaptive capability as its colour pattern varies between years and geographic distribution. Our study assessed the impact of the built urban environment and summers of differing weather conditions on the common wasp by studying the melanic pigmentation on the abdomen. Samples were collected from urban zones in three cities and their adjacent rural zones in Finland. In one location samples were also collected from two different summers to see ...
Environmental stress can affect individual development and fitness in insects. Forest logging is ... more Environmental stress can affect individual development and fitness in insects. Forest logging is a serious environmental stress for forest-specialist insects, such as the mound-building wood ant Formica aquilonia Yarrow 1955, which builds its nests into forests and is dependent on the nutrition provided by the forest habitat. We studied whether the logging causes such a strong environmental stress that it would be visible in disproportionate growth and shape of young winged wood ant gynes (‘queens’) and males. We measured head width, thorax width and wing length of 144 gynes and 100 males from 12 nests from six clear-cut areas, 11 nests from unlogged forest stands and 10 nests in clear-cut—forest margins. We observed disproportionate growth of different body parts and allometric growth of wings in both sexes in areas with different logging-induced disturbance. Gynes had larger heads in clear-cut areas and males had narrowest thoraxes in forest clear-cut edges. With an increasing tho...
It has been generally thought that sex differences in the immune system are the result of the dif... more It has been generally thought that sex differences in the immune system are the result of the differing life history strategies of the sexes, although the available data are not entirely consistent with the hypothesis. In this study, we studied the variation in the immune function in the mound-building wood ant Formica exsecta. F. exsecta has two forms of males, distinguished by size: the small males (micraners) and the large males (macraners), which die after the mating period, whereas females live tens of years laying their eggs. We found that in general males have a lower encapsulation response against nylon monofilament (i.e. lower immune function) than queens. Among males, the micraners had a lower encapsulation rate than the macraners. However, in queens, there was no correlation between size and encapsulation rate. The origin nest had an effect on the encapsulation rate of males: males from the large nests had a stronger encapsulation rate than males from small nests. However, in queens, nest size did not have any effect on encapsulation response. The observed variation between sexes and individuals in the encapsulation rate is discussed in the context of reproductive strategies and parasite-mediated sexual selection.
Studies on individual reproductive success in relation to interspecific competition between dista... more Studies on individual reproductive success in relation to interspecific competition between distantly related taxa are scarce. We studied whether the abundance of red wood ants Formica rufa-group is related to the breeding habitat selection, fecundity and offspring quality in the Eurasian treecreeper Certhia familiaris, an old-growth forest passerine. The nest-box occupancy data were gathered over a five-year study period, whereas the breeding performance analyses were based on a two-year data set. The abundance of wood ants, measured within 50 m around the nest-boxes, was not related to nest-box occupancy rate, fecundity or the physiological stress of nestlings. In contrast, the abundance of wood ants was negatively related to the offspring quality and life-history traits, such as lowered body mass, subcutaneous fat reserves, and tarsus length at fledging. Our results suggest that exploitative competition between distantly related taxa may have considerable and adverse influences on nestling quality as measured by body mass, subcutaneous, fat and tarsus length. Red wood ants may decrease the fitness of treecreepers as the lower body condition of nestlings has the potential to impair recruitment into the breeding population and, additionally, impair the future reproductive effort.
... JOUNI SORVARI ,† ,; HARRI HAKKARAINEN. Article first published online: 23 NOV 2007. ... P., N... more ... JOUNI SORVARI ,† ,; HARRI HAKKARAINEN. Article first published online: 23 NOV 2007. ... P., Niemelä, P. & Karhu, K. (2004) The impact of wood ants (Hymenoptera: Formicidae) on the structure of invertebrate community on mountain birch (Betula pubescens ssp czerepanovii). ...
Body size in animals is affected by both genes and the environment (e.g., the amount of food reso... more Body size in animals is affected by both genes and the environment (e.g., the amount of food resources). In ants, body size is related to several traits in an individual's physiology and life history. For example, a large queen may increase offspring production, thus increasing her overall fitness. In this study, whether sub-optimal environmental conditions affect the body size of queens of the red wood ant, Formica aquilonia Yarrow (Hymenoptera: Formicidae). The sizes (head width in mm) of virgin queens, i.e., gynes, originating from forest interiors (resource rich) and from commercial forest clear-cuts (resource poor) were measured. No differences in the body size of the queens from the two habitats were found. In addition, the within-nest variation in queen size was similar between habitat types. The results indicate that the body size variation of F. aquilonia queens is not sensitive to environmental variation, unlike F. aquilonia workers. The lack of environmental variation in queen size in F. aquilonia may be due to a strong selection in the past to monomorphic size in this obligately polygynous (multi-queened) species.
ABSTRACT Ant nests are rich with various other fauna, and they may be seen as resources for these... more ABSTRACT Ant nests are rich with various other fauna, and they may be seen as resources for these guest species. We studied the species richness and abundance of ant guests in the nests of Formica polyctena by addressing the resource concentration hypothesis, which predicts that nests in high densities would support higher species richness and abundance of specialised guests.In 12 nests we found 1562 individuals belonging to 70 taxa, of which beetles were the most species rich group. The resource concentration hypothesis was supported, as we found the species richness to be higher in nests with close neighbours. There was no relationship between the abundance of associates and the nearest neighbour distance.Non-parametric methods were applied for total species richness estimation. These suggest that additional sampling would yield more associate species.In addition, we studied the similarity of the species composition in the nests and how the distance between the nests correlates with it. Overall, nests from the same area appeared to be most similar with each other. A significant negative trend between geographical distance and similarity of the species composition was found when all species and non-myrmecophiles were tested.For maintaining and conserving high arthropod diversity in temperate and boreal forests, forest management practices preserving dense red wood ant populations should be used if the habitat cannot be protected.
Beer trapping has been carried out annually in the summer in south western Finland (Turku) from 2... more Beer trapping has been carried out annually in the summer in south western Finland (Turku) from 2008 to 2012 inclusive. In 2012, an additional trapping programme was conducted in southern (Helsinki), central (Kuopio) and northern (Kevo) Finland, which also included another trapping location in the south western (Turku) region. The traps were always presented for seven days in each location. While the median wasp Dolichovespula media (Retzius, 1783) was present in all locations, the common wasp Vespula vulgaris Linnaeus, 1758 was found in five out of six locations (20 traps per site). The Kevo individual represents the northernmost record for the median wasp species. The German wasp Vespula germanica (Fabricius, 1793) was surprisingly common in south western and southern Finland. Vespula germanica has a short history of occurrence in Finland and seems to have shifted its range northwards, possibly due to climate change. Some common species of the genus Dolichovespula Rohwer, 1916 wer...
Alive individual adult sawtoothed grain beetle Oryzaephilus surinamensis (Linnaeus, 1758) was dis... more Alive individual adult sawtoothed grain beetle Oryzaephilus surinamensis (Linnaeus, 1758) was discovered inside a nest mound of the red wood ant Formica rufa Linnaeus, 1758 during a survey of myrmecophilous invertebrates. The sawtoothed grain beetle is a widespread indoor pest that has not previously been found in an ant nest. It is one of the most common pests in stored grain and cereal products, but the natural life-style of the species is not known. As the site of discovery was exceptional, we verified the species identification using the DNA barcode. If the sawtoothed grain beetle can live in mounds of red wood ants, the mounds may become widespread source habitats for the future infestations of this serious stored product pest.
ABSTRACT Ants have been suggested to protect forests against insect defoliators. Here, the associ... more ABSTRACT Ants have been suggested to protect forests against insect defoliators. Here, the association between colony size and for-aging distances of two common Eurasian multinest-breeding, mound-building ant species, Formica aquilonia YARROW, 1955 and Formica exsecta NYLANDER, 1846, are compared, and the results are discussed in the context of the species' potential to protect trees from insect defoliators. The distance to the most distant foraging tree was over 100 m in a large nest of F. aquilonia, whereas always less than 10 m in F. exsecta. Foraging distance increased with an increase in colony size in F. aquilonia, but not in F. exsecta. Nest mounds were clearly larger in F. aquilonia, but the foraging distance differences were not due to nest size differences. Foraging distance was larger in F. aquilonia even when the effect of colony size was controlled for statistically. The smaller foraging range of F. exsecta could be compensated by its ability to form dense nest populations, but in Fennoscandian boreal forests it lives in temporarily open habitats and disappears before canopy closure. Therefore it may have a more limited use against insect defoliators than F. aquilonia. Formica aquilonia instead, like other polydomous members of the Formica rufa LINNAEUS, 1761 group, also lives in-side older forests and has large foraging areas and wide-spread multi-nest colonies. Thus it may have greater potential to protect trees against defoliator insects during the lifespan of a forest.
ABSTRACT Red wood ants of the Formica rufa group, as well as their nests, form a vital part of th... more ABSTRACT Red wood ants of the Formica rufa group, as well as their nests, form a vital part of the ecosystems of both European and Siberian boreal and temperate forests. It has been well documented that the nests of red wood ants in clear-cuts do not perform as well as those deeper in the forest. However, clear-cuts may not be a homogeneously poor habitat for such forest-dwelling ants because the distance of the nest site to the edge of the remaining forest may be a significant factor affecting the nest performance. In this study, I compared the probability of nest survival and sexual offspring production between the nests of Formica aquilonia (Yarrow, 1955) in a forest edge zone (distance to the forest edge Keywords: Ants; boreal forests; forest edge; forest management; logging Document Type: Research Article DOI: http://dx.doi.org/10.1080/02827581.2013.766258 Affiliations: Department of Biology, Section of Ecology, University of Turku, Turku, Finland Publication date: July 1, 2013 More about this publication? Editorial Board Information for Authors Subscribe to this Title ingentaconnect is not responsible for the content or availability of external websites $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } $(".descriptionitem").prepend(shortdescription); $(".shortdescription a").click(function() { $(".shortdescription").hide(); $(".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher In this Subject: Forestry By this author: Sorvari, Jouni GA_googleFillSlot("Horizontal_banner_bottom");
Little is known about how anthropogenic changes in nature affect reproduction in social insects s... more Little is known about how anthropogenic changes in nature affect reproduction in social insects such as ants. We studied the effects of clear-cutting on the production of sexual offspring and on the mound size in Formica aquilonia, using neighbouring uncut forests as controls. Nest mounds were smaller in clear-cuts, apparently because they tended to be new bud nests. The basal area of nest mounds decreased towards forest edges. The production of sexual offspring increased with nest mound size. Clear-cutting reduced the production of sexual offspring also when the effect of nest mound size had been factored out. Our results show that anthropogenic changes do have the potential to modify the production of sexual offspring in social insect.
Wide overlaps in morphological characters among species in mound building wood ants of the Formic... more Wide overlaps in morphological characters among species in mound building wood ants of the Formica rufa-group have been a long-standing problem. Previous studies suggest that Formica polyctena samples from Finland may represent two different types based on queen morphology. However, worker caste has not been studied completely. I found that hairiness of workers from different colonies was bimodally distributed. Morphs (based on bimodality) differed in the abundance of erect hairs on eight out of 11 studied body parts. The hairier morph may be result of incomplete reproductive isolation between closely related species.
Sex ratios of ants have been shown to vary with food resource levels in several studies, but it i... more Sex ratios of ants have been shown to vary with food resource levels in several studies, but it is not known whether forest clear-cutting has any effect on sex ratio of aphid-tending forest-dwelling ants. We investigated whether the offspring sex ratio of the forest dwelling ant Formica aquilonia varied as a response to clear-cutting. We found that the proportion of males was smaller in clear-cuts than in adjacent forests. Our results are among the first showing that anthropogenic changes in forest structures may have a potential to modify sex ratios of social insects and other forest-dwelling animals.
The fitness and survival of ant colonies depend on the resources near their nests. These resource... more The fitness and survival of ant colonies depend on the resources near their nests. These resources may be limited due to poor habitat quality or by intra- and interspecific competitions, which in extreme cases may cause the ant colony to perish. We tested the effect of intraspecific competition and habitat degradation (forest clear-cutting) on colony survival by transplanting 26 nests of the red wood ant (Formica aquilonia Yarrow, 1955) in 26 different forest areas that contained 0-11 conspecific alien nests per hectare. F. aquilonia is highly dependent on canopy-dwelling aphids, thus the removal of trees should cause food limitation. During the course of the 4-year experiment, 9 of the forests were partially clear-cut. We found that while forest clear-cutting significantly decreased the colonies' survival, intraspecific competition did not. As a highly polygynous and polydomous species, F. aquilonia seems to tolerate the presence of alien conspecific colonies to a certain extent.
Although the immune functions of insects are known to correlate with body condition and food reso... more Although the immune functions of insects are known to correlate with body condition and food resources, the association between habitat structure and immune function is still largely unknown. We studied the effects of forest clear-cutting on encapsulation rate in gynes and workers in the forestdwelling ant Formica aquilonia. Forest logging resulted in disturbed immunity in workers and gynes. Logging enhanced encapsulation reaction in gynes, whereas decreased that of workers. In gynes, there was a likely trade-off between growth and immune function that was apparent in terms of different investment in size and immune function in different habitats. In workers, however, such associations were not found.
1. Large colonies of ants are known to have a higher propensity for sexual offspring production, ... more 1. Large colonies of ants are known to have a higher propensity for sexual offspring production, probably owing to their high capacity to exploit food resources.
Animals such as social insects that live in colonies can recognize intruders from other colonies ... more Animals such as social insects that live in colonies can recognize intruders from other colonies of the same or different species using colony-specific odors. Such colony odors usually have both a genetic and an environmental origin. When within-colony relatedness is high (i.e., one or very few reproductive queens), colonies comprise genetically distinct entities, and recognition based on genetic cues is reliable. However, when nests contain multiple queens and colonies comprise multiple nests (polydomy), the use of purely genetically determined recognition labels may become impractical. This is due to high within-colony genetic heterogeneity and low between-colony genetic heterogeneity. This may favor the use of environmentally determined recognition labels. However, because nests within polydomous colonies may differ in their microenvironment, the use of environmental labels may also be impractical unless they are actively mixed among the nests. Using a laboratory experiment, we found that both isolation per se and diet composition influenced the cuticular chemical profiles in workers of Formica aquilonia. In addition, the level of aggression increased when both the proportions of dietary ingredients and the availability of food were altered. This suggests that increased aggression was mediated by changes in the chemical profile and that environmental cues can mediate recognition between colonies. These results also suggest that the underlying recognition cues are mutable in response to extrinsic factors such as the amount and the composition of food.
Environmental alteration for urban development prompts ecological changes across urban centres, r... more Environmental alteration for urban development prompts ecological changes across urban centres, ranging out towards the surrounding undisturbed areas. These impact on organisms living across the urban-rural gradient and insects, being widely distributed in nature, are confronted with adaptive choices in such situations. The temperature in urban cores is generally higher due to the urban heat island effect. Thus, insects might modify their behaviour or morphology to cope with the urban environment. The common wasp Vespula vulgaris (L.) has shown adaptive capability as its colour pattern varies between years and geographic distribution. Our study assessed the impact of the built urban environment and summers of differing weather conditions on the common wasp by studying the melanic pigmentation on the abdomen. Samples were collected from urban zones in three cities and their adjacent rural zones in Finland. In one location samples were also collected from two different summers to see ...
Environmental stress can affect individual development and fitness in insects. Forest logging is ... more Environmental stress can affect individual development and fitness in insects. Forest logging is a serious environmental stress for forest-specialist insects, such as the mound-building wood ant Formica aquilonia Yarrow 1955, which builds its nests into forests and is dependent on the nutrition provided by the forest habitat. We studied whether the logging causes such a strong environmental stress that it would be visible in disproportionate growth and shape of young winged wood ant gynes (‘queens’) and males. We measured head width, thorax width and wing length of 144 gynes and 100 males from 12 nests from six clear-cut areas, 11 nests from unlogged forest stands and 10 nests in clear-cut—forest margins. We observed disproportionate growth of different body parts and allometric growth of wings in both sexes in areas with different logging-induced disturbance. Gynes had larger heads in clear-cut areas and males had narrowest thoraxes in forest clear-cut edges. With an increasing tho...
It has been generally thought that sex differences in the immune system are the result of the dif... more It has been generally thought that sex differences in the immune system are the result of the differing life history strategies of the sexes, although the available data are not entirely consistent with the hypothesis. In this study, we studied the variation in the immune function in the mound-building wood ant Formica exsecta. F. exsecta has two forms of males, distinguished by size: the small males (micraners) and the large males (macraners), which die after the mating period, whereas females live tens of years laying their eggs. We found that in general males have a lower encapsulation response against nylon monofilament (i.e. lower immune function) than queens. Among males, the micraners had a lower encapsulation rate than the macraners. However, in queens, there was no correlation between size and encapsulation rate. The origin nest had an effect on the encapsulation rate of males: males from the large nests had a stronger encapsulation rate than males from small nests. However, in queens, nest size did not have any effect on encapsulation response. The observed variation between sexes and individuals in the encapsulation rate is discussed in the context of reproductive strategies and parasite-mediated sexual selection.
Studies on individual reproductive success in relation to interspecific competition between dista... more Studies on individual reproductive success in relation to interspecific competition between distantly related taxa are scarce. We studied whether the abundance of red wood ants Formica rufa-group is related to the breeding habitat selection, fecundity and offspring quality in the Eurasian treecreeper Certhia familiaris, an old-growth forest passerine. The nest-box occupancy data were gathered over a five-year study period, whereas the breeding performance analyses were based on a two-year data set. The abundance of wood ants, measured within 50 m around the nest-boxes, was not related to nest-box occupancy rate, fecundity or the physiological stress of nestlings. In contrast, the abundance of wood ants was negatively related to the offspring quality and life-history traits, such as lowered body mass, subcutaneous fat reserves, and tarsus length at fledging. Our results suggest that exploitative competition between distantly related taxa may have considerable and adverse influences on nestling quality as measured by body mass, subcutaneous, fat and tarsus length. Red wood ants may decrease the fitness of treecreepers as the lower body condition of nestlings has the potential to impair recruitment into the breeding population and, additionally, impair the future reproductive effort.
... JOUNI SORVARI ,† ,; HARRI HAKKARAINEN. Article first published online: 23 NOV 2007. ... P., N... more ... JOUNI SORVARI ,† ,; HARRI HAKKARAINEN. Article first published online: 23 NOV 2007. ... P., Niemelä, P. & Karhu, K. (2004) The impact of wood ants (Hymenoptera: Formicidae) on the structure of invertebrate community on mountain birch (Betula pubescens ssp czerepanovii). ...
Body size in animals is affected by both genes and the environment (e.g., the amount of food reso... more Body size in animals is affected by both genes and the environment (e.g., the amount of food resources). In ants, body size is related to several traits in an individual's physiology and life history. For example, a large queen may increase offspring production, thus increasing her overall fitness. In this study, whether sub-optimal environmental conditions affect the body size of queens of the red wood ant, Formica aquilonia Yarrow (Hymenoptera: Formicidae). The sizes (head width in mm) of virgin queens, i.e., gynes, originating from forest interiors (resource rich) and from commercial forest clear-cuts (resource poor) were measured. No differences in the body size of the queens from the two habitats were found. In addition, the within-nest variation in queen size was similar between habitat types. The results indicate that the body size variation of F. aquilonia queens is not sensitive to environmental variation, unlike F. aquilonia workers. The lack of environmental variation in queen size in F. aquilonia may be due to a strong selection in the past to monomorphic size in this obligately polygynous (multi-queened) species.
ABSTRACT Ant nests are rich with various other fauna, and they may be seen as resources for these... more ABSTRACT Ant nests are rich with various other fauna, and they may be seen as resources for these guest species. We studied the species richness and abundance of ant guests in the nests of Formica polyctena by addressing the resource concentration hypothesis, which predicts that nests in high densities would support higher species richness and abundance of specialised guests.In 12 nests we found 1562 individuals belonging to 70 taxa, of which beetles were the most species rich group. The resource concentration hypothesis was supported, as we found the species richness to be higher in nests with close neighbours. There was no relationship between the abundance of associates and the nearest neighbour distance.Non-parametric methods were applied for total species richness estimation. These suggest that additional sampling would yield more associate species.In addition, we studied the similarity of the species composition in the nests and how the distance between the nests correlates with it. Overall, nests from the same area appeared to be most similar with each other. A significant negative trend between geographical distance and similarity of the species composition was found when all species and non-myrmecophiles were tested.For maintaining and conserving high arthropod diversity in temperate and boreal forests, forest management practices preserving dense red wood ant populations should be used if the habitat cannot be protected.
Beer trapping has been carried out annually in the summer in south western Finland (Turku) from 2... more Beer trapping has been carried out annually in the summer in south western Finland (Turku) from 2008 to 2012 inclusive. In 2012, an additional trapping programme was conducted in southern (Helsinki), central (Kuopio) and northern (Kevo) Finland, which also included another trapping location in the south western (Turku) region. The traps were always presented for seven days in each location. While the median wasp Dolichovespula media (Retzius, 1783) was present in all locations, the common wasp Vespula vulgaris Linnaeus, 1758 was found in five out of six locations (20 traps per site). The Kevo individual represents the northernmost record for the median wasp species. The German wasp Vespula germanica (Fabricius, 1793) was surprisingly common in south western and southern Finland. Vespula germanica has a short history of occurrence in Finland and seems to have shifted its range northwards, possibly due to climate change. Some common species of the genus Dolichovespula Rohwer, 1916 wer...
Alive individual adult sawtoothed grain beetle Oryzaephilus surinamensis (Linnaeus, 1758) was dis... more Alive individual adult sawtoothed grain beetle Oryzaephilus surinamensis (Linnaeus, 1758) was discovered inside a nest mound of the red wood ant Formica rufa Linnaeus, 1758 during a survey of myrmecophilous invertebrates. The sawtoothed grain beetle is a widespread indoor pest that has not previously been found in an ant nest. It is one of the most common pests in stored grain and cereal products, but the natural life-style of the species is not known. As the site of discovery was exceptional, we verified the species identification using the DNA barcode. If the sawtoothed grain beetle can live in mounds of red wood ants, the mounds may become widespread source habitats for the future infestations of this serious stored product pest.
ABSTRACT Ants have been suggested to protect forests against insect defoliators. Here, the associ... more ABSTRACT Ants have been suggested to protect forests against insect defoliators. Here, the association between colony size and for-aging distances of two common Eurasian multinest-breeding, mound-building ant species, Formica aquilonia YARROW, 1955 and Formica exsecta NYLANDER, 1846, are compared, and the results are discussed in the context of the species' potential to protect trees from insect defoliators. The distance to the most distant foraging tree was over 100 m in a large nest of F. aquilonia, whereas always less than 10 m in F. exsecta. Foraging distance increased with an increase in colony size in F. aquilonia, but not in F. exsecta. Nest mounds were clearly larger in F. aquilonia, but the foraging distance differences were not due to nest size differences. Foraging distance was larger in F. aquilonia even when the effect of colony size was controlled for statistically. The smaller foraging range of F. exsecta could be compensated by its ability to form dense nest populations, but in Fennoscandian boreal forests it lives in temporarily open habitats and disappears before canopy closure. Therefore it may have a more limited use against insect defoliators than F. aquilonia. Formica aquilonia instead, like other polydomous members of the Formica rufa LINNAEUS, 1761 group, also lives in-side older forests and has large foraging areas and wide-spread multi-nest colonies. Thus it may have greater potential to protect trees against defoliator insects during the lifespan of a forest.
ABSTRACT Red wood ants of the Formica rufa group, as well as their nests, form a vital part of th... more ABSTRACT Red wood ants of the Formica rufa group, as well as their nests, form a vital part of the ecosystems of both European and Siberian boreal and temperate forests. It has been well documented that the nests of red wood ants in clear-cuts do not perform as well as those deeper in the forest. However, clear-cuts may not be a homogeneously poor habitat for such forest-dwelling ants because the distance of the nest site to the edge of the remaining forest may be a significant factor affecting the nest performance. In this study, I compared the probability of nest survival and sexual offspring production between the nests of Formica aquilonia (Yarrow, 1955) in a forest edge zone (distance to the forest edge Keywords: Ants; boreal forests; forest edge; forest management; logging Document Type: Research Article DOI: http://dx.doi.org/10.1080/02827581.2013.766258 Affiliations: Department of Biology, Section of Ecology, University of Turku, Turku, Finland Publication date: July 1, 2013 More about this publication? Editorial Board Information for Authors Subscribe to this Title ingentaconnect is not responsible for the content or availability of external websites $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } $(".descriptionitem").prepend(shortdescription); $(".shortdescription a").click(function() { $(".shortdescription").hide(); $(".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher In this Subject: Forestry By this author: Sorvari, Jouni GA_googleFillSlot("Horizontal_banner_bottom");
Little is known about how anthropogenic changes in nature affect reproduction in social insects s... more Little is known about how anthropogenic changes in nature affect reproduction in social insects such as ants. We studied the effects of clear-cutting on the production of sexual offspring and on the mound size in Formica aquilonia, using neighbouring uncut forests as controls. Nest mounds were smaller in clear-cuts, apparently because they tended to be new bud nests. The basal area of nest mounds decreased towards forest edges. The production of sexual offspring increased with nest mound size. Clear-cutting reduced the production of sexual offspring also when the effect of nest mound size had been factored out. Our results show that anthropogenic changes do have the potential to modify the production of sexual offspring in social insect.
Wide overlaps in morphological characters among species in mound building wood ants of the Formic... more Wide overlaps in morphological characters among species in mound building wood ants of the Formica rufa-group have been a long-standing problem. Previous studies suggest that Formica polyctena samples from Finland may represent two different types based on queen morphology. However, worker caste has not been studied completely. I found that hairiness of workers from different colonies was bimodally distributed. Morphs (based on bimodality) differed in the abundance of erect hairs on eight out of 11 studied body parts. The hairier morph may be result of incomplete reproductive isolation between closely related species.
Sex ratios of ants have been shown to vary with food resource levels in several studies, but it i... more Sex ratios of ants have been shown to vary with food resource levels in several studies, but it is not known whether forest clear-cutting has any effect on sex ratio of aphid-tending forest-dwelling ants. We investigated whether the offspring sex ratio of the forest dwelling ant Formica aquilonia varied as a response to clear-cutting. We found that the proportion of males was smaller in clear-cuts than in adjacent forests. Our results are among the first showing that anthropogenic changes in forest structures may have a potential to modify sex ratios of social insects and other forest-dwelling animals.
The fitness and survival of ant colonies depend on the resources near their nests. These resource... more The fitness and survival of ant colonies depend on the resources near their nests. These resources may be limited due to poor habitat quality or by intra- and interspecific competitions, which in extreme cases may cause the ant colony to perish. We tested the effect of intraspecific competition and habitat degradation (forest clear-cutting) on colony survival by transplanting 26 nests of the red wood ant (Formica aquilonia Yarrow, 1955) in 26 different forest areas that contained 0-11 conspecific alien nests per hectare. F. aquilonia is highly dependent on canopy-dwelling aphids, thus the removal of trees should cause food limitation. During the course of the 4-year experiment, 9 of the forests were partially clear-cut. We found that while forest clear-cutting significantly decreased the colonies' survival, intraspecific competition did not. As a highly polygynous and polydomous species, F. aquilonia seems to tolerate the presence of alien conspecific colonies to a certain extent.
Although the immune functions of insects are known to correlate with body condition and food reso... more Although the immune functions of insects are known to correlate with body condition and food resources, the association between habitat structure and immune function is still largely unknown. We studied the effects of forest clear-cutting on encapsulation rate in gynes and workers in the forestdwelling ant Formica aquilonia. Forest logging resulted in disturbed immunity in workers and gynes. Logging enhanced encapsulation reaction in gynes, whereas decreased that of workers. In gynes, there was a likely trade-off between growth and immune function that was apparent in terms of different investment in size and immune function in different habitats. In workers, however, such associations were not found.
1. Large colonies of ants are known to have a higher propensity for sexual offspring production, ... more 1. Large colonies of ants are known to have a higher propensity for sexual offspring production, probably owing to their high capacity to exploit food resources.
Animals such as social insects that live in colonies can recognize intruders from other colonies ... more Animals such as social insects that live in colonies can recognize intruders from other colonies of the same or different species using colony-specific odors. Such colony odors usually have both a genetic and an environmental origin. When within-colony relatedness is high (i.e., one or very few reproductive queens), colonies comprise genetically distinct entities, and recognition based on genetic cues is reliable. However, when nests contain multiple queens and colonies comprise multiple nests (polydomy), the use of purely genetically determined recognition labels may become impractical. This is due to high within-colony genetic heterogeneity and low between-colony genetic heterogeneity. This may favor the use of environmentally determined recognition labels. However, because nests within polydomous colonies may differ in their microenvironment, the use of environmental labels may also be impractical unless they are actively mixed among the nests. Using a laboratory experiment, we found that both isolation per se and diet composition influenced the cuticular chemical profiles in workers of Formica aquilonia. In addition, the level of aggression increased when both the proportions of dietary ingredients and the availability of food were altered. This suggests that increased aggression was mediated by changes in the chemical profile and that environmental cues can mediate recognition between colonies. These results also suggest that the underlying recognition cues are mutable in response to extrinsic factors such as the amount and the composition of food.
Uploads
Papers by J. Sorvari