Co-occurrence patterns of wood-decaying fungi and ants in dead pines of South Korea

Interaction between fungi and insects such as ants, beetles, wasps and termites inhabiting dead pine trees has significant ecological implication in the forest as they can decompose wood debris and add nutrients to the soil; however, only scarce information is available regarding the interaction between wood-decaying fungi and ants. We investigated wood-decaying fungi co-occurring with ants in dead pine trees of South Korea. A total of 57 pairs of wood-decaying fungi and ants were collected from 11 localities. 30 species of wood-decaying fungi and 14 species of ants were identified based on morphology and molecular analysis. Fungal species belonging to Trichaptum, Xylodon, Hyphodontia, and Ceriporia were dominant and co-occurred with common ant species of Lasius, Camponotus, Pristomyrmex, and Crematogaster across most of the sampling sites. This study provides a new baseline in unravelling the complex interaction between wood-decaying fungi and ants in forest ecosystems.     

Arboreal thorn-dwelling ants coexisting on the savannah ant-plant, Vachellia erioloba, use domatia morphology to select nest sites

Nest site selection in arboreal, domatia-dwelling ants, particularly those coexisting on a single host plant, is little understood. To examine this phenomenon we studied the African savannah tree Vachellia erioloba, which hosts ants in swollen-thorn domatia. We found four ant species from different genera (Cataulacus intrudens, Tapinoma subtile, Tetraponera ambigua and an unidentified Crematogaster species). In contrast to other African ant plants, many V. erioloba trees (41 % in our survey) were simultaneously co-occupied by more than one ant species. Our study provides quantitative field data describing: (1) aspects of tree and domatia morphology relevant to supporting a community of mutualist ants, (2) how ant species occupancy varies with domatia morphology and (3) how ant colony size varies with domatia size and species. We found that Crematogaster sp. occupy the largest thorns, followed by C. intrudens, with T. subtile in the smallest thorns. Thorn age, as well as nest entrance hole size correlated closely with ant species occupant. These differing occupancy patterns may help to explain the unusual coexistence of three ant species on individual myrmecophytic trees. In all three common ant species, colony size, as measured by total number of ants, increased with domatia size. Additionally, domatia volume and species identity interact to predict ant numbers, suggesting differing responses between species to increased availability of nesting space. The proportion of total ants in nests that were immatures varied with thorn volume and species, highlighting the importance of domatia morphology in influencing colony structure.     

Edge,area and anthropization effects on mangrove-dwelling ant communities

In mangroves the habitat fragmentation has contributed to area reduction and increased edge extension, as well as other anthropogenic consequences that can change abiotic conditions, interfere with ecosystem functioning and lead to the loss of biodiversity. These impacts may affect terrestrial and marine invertebrates living in this coastal system. This study investigated the effects of fragment characteristics (size and matrix type) and distance to edge on ant richness, occurrence of functional groups and of the most frequent species in mangroves in North-Eastern Brazil. Our research covered ten mangrove fragments. We used sardine and honey baits in twelve randomly selected points per area. Twenty-five species of ants were recorded, with Camponotus arboreus, Crematogaster erecta, Azteca sp. and Neoponera villosa being the most frequent. Only four functional groups were found, the most representative of which were the Arboreal Omnivores with Massive Recruitment and the Generalist Predators. No relationship was found between the response variables and the environmental characteristics. Mangroves ants are mostly arboreal; thus, the pattern of competition between ant species or even tree architecture elements may have stronger effects than those related to anthropization, loss of area and fragmentation in this environment. Furthermore, the harsh physical conditions in the mangrove serve as barriers for most exotic species and to some functional groups of ants. This study highlights the natural restrictive nesting and foraging conditions in mangrove areas as the powerful forces in ant community structuring, possibly even more than anthropization itself.     

Symbiotic ants as an alternative defense against giraffe herbivory in spinescent Acacia drepanolobium

Summary We explore here the occurrence of aggressive ants in an apparently symbiotic relationship with the savanna tree Acacia drepanolobium and their effects on giraffe herbivory on the Athi-Kapiti Plains, Kenya. Trees taller than 1.3 m were more likely to be occupied by aggressive ants in the genus Crematogaster than were shorter trees. Ants wereconcentrated on shoot tips, the plant parts preferred by giraffes. Trees with relatively more foliage had more swarming ants than did trees with less foliage. The feeding behavior of individual freeranging giraffes on Acacia drepanolobium was studied. Giraffe calves exhibited a strong sensitivity to Crematogaster ants inhabiting A. drepanolobium, feeding for significantly shorter periods on trees with a greater number of aggressive ants. Older giraffes were apparently less sensitive to ants, and did not feed for shorter periods on trees with fuller foliage, despite significantly greater ant activity on these plants. The thorns of A. drepanolobium are significantly shorter than are the thorns of A. seyal, a species without symbiotic ants, a pattern that may indicate a trade-off between ants and thorns as defenses.     

Patterns of the <Emphasis Type="Italic">Crematogaster-Macaranga</Emphasis> association: The ant partner makes the difference

Summary. One of the most species-rich ant-plant mutualisms worldwide is the palaeotropical Crematogaster-Macaranga system. Although the biogeography and ecology of both partners have been extensively studied, little is known about the temporal structuring and the dynamics of the association. In this study we compared life-history traits of the specific Crematogaster (Decacrema) partner-ants and followed the development of ant colonies on eight different Macaranga host plant species, from colony founding on saplings to adult trees in a snapshot fashion. We found differences in the onset of alate production, queen number and mode of colony founding in the ant species and examined the consequences of these differences for the mutualism with the host plant. The lifespan of some host plants and their specific ant partners seemed to be well matched whereas on others we found an ontogenetic succession of specific partner ants. The partner ants of saplings or young plants often differed from specific partner ants found on larger trees of the same species. Not all specific Crematogaster species can re-colonize the crown region of adult trees, thus facilitating a change of ant species. Therefore lifespan of the ant colony as well as colony founding behaviour of the different partner ant species are important for these ontogenetic changes. The lifespan of a colony of two species can be prolonged via secondary polygyny. For the first time, also primary polygyny (pleometrosis) is reported from this myrmecophytic system.     

Reduced ant defenses in <Emphasis Type="Italic">Macaranga</Emphasis> myrmecophytes (Euphorbiaceae) infested with a winged phasmid <Emphasis Type="Italic">Orthomeria cuprinus</Emphasis>

Macaranga is a tree genus that includes many species of myrmecophytes, which are plants that harbor ant colonies within hollow structures known as domatia. The symbiotic ants (plant–ants) protect their host plants against herbivores; this defense mechanism is called ‘ant defense’. A Bornean phasmid species Orthomeria cuprinus feeds on two myrmecophytic Macaranga species, Macaranga beccariana and Macaranga hypoleuca, which are obligately associated with Crematogaster ant species. The phasmids elude the ant defense using specialized behavior. However, the mechanisms used by the phasmid to overcome ant defenses have been insufficiently elucidated. We hypothesized that O. cuprinus only feeds on individual plants with weakened ant defenses. To test the hypothesis, we compared the ant defense intensity in phasmid-infested and non-infested M. beccariana trees. The number of plant–ants on the plant surface, the ratio of plant–ant biomass to tree biomass, and the aggressiveness of plant–ants towards experimentally introduced herbivores were significantly lower on the phasmid-infested trees than on the non-infested trees. The phasmid nymphs experimentally introduced into non-infested trees, compared with those experimentally introduced into phasmid-infested trees, were more active on the plant surface, avoiding the plant–ants. These results support the hypothesis and suggest that ant defenses on non-infested trees effectively prevent the phasmids from remaining on the plants. Thus, we suggest that O. cuprinus feeds only on the individual M. beccariana trees having decreased ant defenses, although the factors that reduce the intensity of the ant defenses remain unclear.     

Chimpanzees detect ant-inhabited dead branches and stems: a study of the utilization of plant–ant relationships in the Mahale Mountains, Tanzania

Chimpanzees in the Mahale Mountains of Tanzania consume several species of stem- and branch-inhabiting ants throughout the year, without tools. Those ants are cryptic species, and it was unknown how to find them constantly. There has been little research on how the chimpanzees locate these ants. In this study, I use behavioral observations of the chimpanzee predators and surveys of the ant fauna and plants across different habitats to test the hypothesis that chimpanzees use plant species as a cue to efficiently locate ant colonies in litter units (dead parts of the plant). Ants were found to be associated with live plants and with spaces within litter units which provide nesting places. Such ant–plant litter relationships were not necessarily as strong as the mutualism often observed between live plants and ants. The proportion of available litter units inhabited by ants was 20 %, and litter units of three plant species (Vernonia subligera, Dracaena usambarensis, and Senna spectabilis) were well occupied by ants in the home range of the chimpanzees. The ant-inhabited ratio in chimpanzee-foraged litter units was higher than that in the available units in the home range. Chimpanzees fed more often on Crematogaster spp. than on other resident ants and at a higher rate than expected from their occurrence in the litter units. Above three plant species were well occupied by Crematogaster sp. 3 or C. sp. 18. It is concluded that chimpanzees locate ants by selecting litter units of plant species inhabited by ants.     

Ants on swollen-thorn acacias: species coexistence in a simple system

 On the black cotton soils of the Laikipia ecosystem in Kenya, two swollen-thorn acacia species support nine ant species, four of which are apparently obligate plant-ants. Among the ants, there are five species of Crematogaster, two species of Camponotus, and one each of Tetraponera and Lepisota. Acacia drepanolobium is host to four ant species that are both common and mutually exclusive. These four ant species, and an additional non-exclusive ant species, tend to occur on trees of different sizes, implying a succession of ant occupants. Nonetheless, all four exclusive species occur in substantial proportions on trees of intermediate size. There is direct evidence that an early successional ant species (Tetraponera penzigi) is actively evicted by two late successional ant species in the genus Crematogaster. There was also some evidence of height differentiation among ant species resident on A. seyal. Different acacia-ant species had different direct effects on A. drepanolobium. Extrafloral nectaries were eaten and destroyed only on trees inhabited by Tetraponera. Axillary shoots were eaten only on trees inhabited by C. nigriceps (potentially another early successional ant). This was associated with more new terminal shoots and healthier leaves than other trees, but also the virtual elimination of flowering and fruiting. Different resident acacia-ant species also had characteristic relationships with other insects. Among the four mutually exclusive ant species, only Crematogaster sjostedti was associated with two species of Camponotus, at least one of which (C. rufoglaucus) appears to be a foraging non-resident. A. drepanolobium trees occupied by C. sjostedti were also far more heavily infested with leaf galls than were trees occupied by other ant species. A. drepanolobium trees occupied by C. mimosae and C. sjostedti uniquely had tended adult scale insects. This diversity of ant inhabitants, and their strikingly different relationships with their hosts and other insect species, are examples of coexisting diversity on an apparently uniform resource. Received: 13 November 1995 / Accepted: 16 May 1996     

Spatiotemporal patterns of intraspecific aggression in the invasive Argentine ant

The Argentine ant, Linepithema humile, is a widespread invasive species characterized by reduced intraspecific aggression within introduced populations. To illuminate the mechanisms underlying nestmate recognition in Argentine ants, we studied the spatial and temporal fidelity of intraspecific aggression in an introduced population of Argentine ants within which intraspecific aggression does occur. We quantified variation in the presence or absence of intraspecific aggression among nests over time both in the field and under controlled laboratory conditions to gain insight into the role of environmental factors as determinants of nestmate discriminatory ability. In addition, we compared levels of intraspecific aggression between nest pairs to the similarity of their cuticular hydrocarbons to determine the potential role of these compounds as labels for nestmate discrimination. In both field and laboratory comparisons, nest pairs behaved in a consistent manner throughout the course of the experiment: pairs that fought did so for an entire year, and pairs that did not fight remained nonaggressive. Moreover, we found a negative relationship between cuticular hydrocarbon similarity and the degree of aggression between nests, suggesting that these hydrocarbons play a role in nestmate discriminatory ability. In contrast to the prevailing pattern, ants from one site showed a marked change in behaviour during the course of this study. A concomitant change was also seen in the cuticular hydrocarbon profiles of ants from this site. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.     

Spatial Distribution of Dominant Arboreal Ants in a Malagasy Coastal Rainforest: Gaps and Presence of an Invasive Species

We conducted a survey along three belt transects located at increasing distances from the coast to determine whether a non-random arboreal ant assemblage, such as an ant mosaic, exists in the rainforest on the Masoala Peninsula, Madagascar. In most tropical rainforests, very populous colonies of territorially dominant arboreal ant species defend absolute territories distributed in a mosaic pattern. Among the 29 ant species recorded, only nine had colonies large enough to be considered potentially territorially dominant; the remaining species had smaller colonies and were considered non-dominant. Nevertheless, the null-model analyses used to examine the spatial structure of their assemblages did not reveal the existence of an ant mosaic. Inland, up to 44% of the trees were devoid of dominant arboreal ants, something not reported in other studies. While two Crematogaster species were not associated with one another, Brachymyrmex cordemoyi was positively associated with Technomyrmex albipes, which is considered an invasive species—a non-indigenous species that has an adverse ecological effect on the habitats it invades. The latter two species and Crematogaster ranavalonae were mutually exclusive. On the other hand, all of the trees in the coastal transect and at least 4 km of coast were occupied by T. albipes, and were interconnected by columns of workers. Technomyrmex albipes workers collected from different trees did not attack each other during confrontation tests, indicating that this species has formed a supercolony along the coast. Yet interspecific aggressiveness did occur between T. albipes and Crematogaster ranavalonae, a native species which is likely territorially dominant based on our intraspecific confrontation tests. These results suggest that the Masoala rainforest is threatened by a potential invasion by T. albipes, and that the penetration of this species further inland might be facilitated by the low density of native, territorially dominant arboreal ants normally able to limit its progression.     

Two new myrmecophytic associations from the Malay Peninsula: Ants of the genusCladomyrma (Formicidae,Camponotinae) as partners ofSaraca thaipingensis (Caesalpiniaceae) andCrypteronia griffithii (Crypteroniaceae)

Summary In Peninsular Malaysia the treesSaraca thaipingensis (Caesalpiniaceae) andCrypteronia griffithii (Crypteroniaceae) are inhabited by ants. In the vicinity of Gombak, near Kuala Lumpur, the hollow internodes of youngSaraca thaipingensis plants are colonized mainly by twoCladomyrma species. In larger trees aCrematogaster sp. is also found.Crypteronia griffithii is inhabited by a third species ofCladomyrma. None of these species is conspecific with any of the threeCladomyrma taxa so far described. The colonies are founded by single mated queens, which have a conspicuous, sphecid wasp-like behaviour when searching for host plants and nest sites. They chew holes into the plant internodes and hollow them out to provide nest sites. Coccids and pseudococcids are cultivated within the internodes. The homopterans are not carried by queens on their nuptial flights. They apparently find their way by themselves into the cavities or are perhaps carried there by the worker ants. TheCladomyrma ants onCrypteronia are not aggressive, in contrast to those onSaraca thaipingensis.The relationship ofCrypteronia with ants seems to be obligatory, whereasSaraca was only partly colonized byCladomyrma. The interaction ofSaraca withCrematogaster sp. is loose and facultative, since theCrematogaster sp. also lives on other three species. Our studies have now revealed fourCladomyrma spp. which are regularly associated with plants. The genus therefore seems to have an entirely myrmecophytic way of life.     

Thorn‐dwelling ants provide antiherbivore defence for camelthorn trees,Vachellia erioloba,in Namibia

Ants are widely employed by plants as an antiherbivore defence. A single host plant can associate with multiple, symbiotic ant species, although usually only a single ant species at a time. Different plant‐ant species may vary in the degree to which they defend their host plant. In Kenya, ant–acacia interactions are well studied, but less is known about systems elsewhere in Africa. A southern African species, Vachellia erioloba, is occupied by thorn‐dwelling ants from three different genera. Unusually, multiple colonies of all these ants simultaneously and stably inhabit trees. We investigated if the ants on V. erioloba (i) deter insect herbivores; (ii) differ in their effectiveness depending on the identity of the herbivore; and (iii) protect the tree against an important herbivore, the larvae of the lepidopteran Gonometa postica. We show that experimental exclusion of ants leads to greater levels of herbivory on trees. The ants inhabiting V. erioloba are an effective deterrent against hemipteran and coleopteran, but not lepidopteran herbivores. Defensive services do not vary among ant species, but only Crematogaster ants exhibit aggression towards G. postica. This highlights the potential of the V. erioloba–ant mutualism for studying ant–plant interactions that involve multiple, simultaneously resident thorn‐dwelling ant species.     

How plants shape the ant community in the Amazonian rainforest canopy: the key role of extrafloral nectaries and homopteran honeydew

Ant-plant interactions in the canopy of a lowland Amazonian rainforest of the upper Orinoco, Venezuela, were studied using a modified commercial crane on rails (Surumoni project). Our observations show a strong correlation between plant sap exudates and both abundance of ants and co-occurrence of ant species in tree canopies. Two types of plant sap sources were compared: extrafloral nectaries (EFNs) and honeydew secretions by homopterans. EFNs were a frequent food source for ants on epiphytes (Philodendron spp., Araceae) and lianas (Dioclea, Fabaceae), but rare on canopy trees in the study area, whereas the majority of trees were host to aggregations of homopterans tended by honeydew-seeking ants (on 62% of the trees examined). These aggregations rarely occurred on epiphytes. Baited ant traps were installed on plants with EFNs and in the crowns of trees from three common genera, including trees with and without ant-tended homopterans: Goupia glabra (Celastraceae), Vochysia spp. (Vochysiaceae), and Xylopia spp. (Annonaceae). The number of ant workers per trap was significantly higher on plants offering one of the two plant sap sources than on trees without such resources. Extrafloral nectaries were used by a much broader spectrum of ant species and genera than honeydew, and co-occurrence of ant species (in traps) was significantly higher on plants bearing EFNs than on trees. Homopteran honeydew (Coccidae and Membracidae), on the other hand, was mostly monopolised by a single ant colony per tree. Homopteran-tending ants were generally among the most dominant ants in the canopy. The most prominent genera were Azteca, Dolichoderus (both Dolichoderinae), Cephalotes, Pheidole, Crematogaster (all Myrmicinae), and Ectatomma (Ponerinae). Potential preferences were recorded between ant and homopteran species, and also between ant-homopteran associations and tree genera. We hypothesize that the high availability of homopteran honeydew provides a key resource for ant mosaics, where dominant ant colonies and species maintain mutually exclusive territories on trees. In turn, we propose that for nourishment of numerous ants of lower competitive capacity, Philodendron and other sources of EFNs might be particularly important.     

Ant colonization of Maieta guianensis seedlings,an Amazon ant-plant

The ants Pheidole minutula and Crematogaster sp. are obligate inhabitants of the ant-plant Maieta guianensis. They nest and reproduce exclusively in this and a few other Amazon melastome ant-plants. Experimental transplants of uncolonized M. guianensis seedlings to sites at different distances from established colonies of these two ant species, which are sources of founding queens, have shown that distance is an important factor affecting seedling colonization by ants. The proportion of colonized seedlings and the average number of colonizations per seedling, both by Crematogaster sp. and P. minutula, decreased as distance from established colonies increased. Seedling colonization was also affected by rainfall and fewer seedlings were colonized during the dry season, especially by P. minutula, than during the rainy season. P. minutula queens usually cooperate with each other during colony foundation, a behaviour not observed among founding queens of Crematogaster sp. Competition between these two ant species for host-plants appears to be strong as 63.6% of the seedlings colonized by Crematogaster sp. were also colonized by P. minutula during a 15-month observational period. However, there was generally an interval of a few months between colonizations, possibly giving the first species to colonize the plant a better chance of domination on this plant.     

Post-fire spread of alien plant species in a mixed broad-leaved forest of the Insubric region

How do tree species regenerate and which ecological conditions are required after forest fire in the Insubric region of the Alps? Are indigenous stand-forming tree species resistant over the invasion of alien plant species after such a disturbance? We addressed these questions in a case study in the Swiss canton of Ticino. In April 2006, a surface fire with severe intensity burnt a forest area of 55 ha on a south-facing slope (400-800 m.a.s.l.). The dominant trees in the investigated area were chestnut (Castanea sativa Mill.), beech (Fagus sylvatica L.) and deciduous oaks (Quercus spp.) mixed with tree species of intermediate height. Vegetation data were collected in May and August 2009 by systematic sampling. Resprouting of the survived trees and generative regeneration were analysed by counting vegetative shoots from sprouting stools, of seedling age, height and damage rate, respectively. Different vegetation structures related to low or high fire intensity were clearly visible three years after the forest fire, creating various habitats for both new invaders and seedlings of the stand-forming trees. The dominant chestnut was the only tree species that regenerated effectively by sprouting from stools. Seedlings of the stand-forming trees grew in high abundance under shadow conditions close to their mother trees which provided the seed source. In contrast, pioneer trees invaded patches where full light was available. Under such conditions the two main woody alien plant species, Ailanthus altissima and Robinia pseudoacacia, grew in high abundance. Due to the different ecological requirements of indigenous and alien tree seedlings, not any interaction between the two groups was detected.     

Plant Ontogeny as a Conditionality Factor in the Protective Effect of Ants on a Neotropical Tree

The outcome of any interspecific interaction is often determined by the ecological context in which the interacting species are embedded. Plant ontogeny may represent an important source of variation in the outcome of ant–plant mutualisms, as the level of investment in ant rewards, in alternative (non‐biotic) defenses, or both, may be modulated by the plant's developmental stage. In addition, the abundance and identities of the ants involved in the interaction may change during ontogeny of the host‐plant. Here, we evaluated if plant ontogeny affects the interaction between ants and a savanna tree species (Caryocar brasiliense) that produces extrafloral nectar. We found fewer ants per branch and fewer species of ants per tree in juvenile than in reproductive trees of medium and large size. In addition, large‐sized reproductive trees were more likely to host more aggressive ants than were medium‐sized reproductive or juvenile trees. Such differences strongly affected the outcome of the interaction between ants and their host‐plants, as the magnitude of the effect of ants on herbivory was much stronger for large trees than for juvenile ones. The fact that we did not find significant ontogenetic variation in the concentration of leaf tannins suggests that the observed differences in herbivory did not result from a differential investment in chemical defenses among different‐sized plants. Overall, the results of our study indicate that the developmental stage of the host plant is an important factor of conditionality in the interaction between C. brasiliense and arboreal foraging ants.     

Observations on the Ecology of Weaver Ants (Oecophylla smaragdina Fabricius) in a Thai Mangrove Ecosystem and Their Effect on Herbivory of Rhizophora mucronata Lam.

Ants of the genus Oecophylla are predators of other insects and are able to protect a variety of terrestrial plants against pest insects; however, observations on the ecology of these ants in mangrove forests are lacking. General observations on the ecology of Oecophylla smaragdina were carried out in a Thai mangrove forest to determine if these ants can protect their host plants in less favorable mangrove habitats. Leaf herbivory and the density of O. smaragdina ants were measured on Rhizophora mucronata trees at two sites. The results showed a negative correlation between ant density and herbivory. At both sites, the mean percent damaged leaf area was more than four times higher on trees without ants compared to “ant‐trees.” A significant negative correlation was found between tree mean percent leaf damage and the density of ants on the tree. Furthermore, on trees with ants, there was less herbivory on leaves close to ant nests compared to other leaves on the tree. Most damage was caused by chrysomelid beetles (62%) and sesarmid crabs (25%) and both types of herbivory were significantly reduced on ant‐trees.     

Extrafloral nectar as a driver of arboreal ant communities at the site‐scale in Brazilian savanna

Despite years of study, it remains unclear if and to what extent the effects of extra‐floral nectaries (EFNs) on arboreal ants observed on individual trees scale up to larger spatial scales. Here, we address this issue in Brazilian savanna and tested three predictions: (i) Trees with EFN have higher richness of arboreal ant species than trees without; (ii) Arboreal ant species richness increases with the proportion of total EFN‐bearing trees at the site scale, due to a higher occurrence of non‐core ant species; (iii) Ant species composition changes with the proportion of EFN‐bearing trees at the site scale. We sampled arboreal ants in 32 plots with EFN‐bearing trees ranging from 0% to 60% of all trees. We sampled 72 ant species, from which 17 (mostly belonging to Camponotus, Cephalotes and Crematogaster) were identified as core species in at least one of the ant‐EFN networks in the 32 plots. Ant species richness was significantly higher on EFN‐bearing trees. We identified 11 ant species that preferentially occurred on EFN‐bearing trees, all of which were core partners in networks. Species richness at the site scales increased with the proportion of EFN‐bearing trees, regardless of tree density and richness; this pattern was due to a higher occurrence of non‐core ant species. Finally, species composition also varied with the proportion of EFN‐bearing trees. Therefore, we found that the presence of EFNs not only influences arboreal ants on individual trees but also has a substantial effect on the ant‐EFN network on a broader community scale. The increase in non‐core species site scale reveals that this interaction is unlikely to result in substantially enhanced protection services for EFN‐bearing plants.     

Congruence of Microsatellite and Mitochondrial DNA Variation in Acrobat Ants (Crematogaster Subgenus Decacrema,Formicidae: Myrmicinae) Inhabiting Macaranga (Euphorbiaceae) Myrmecophytes

A previously reported mitochondrial DNA (mtDNA) phylogeny of Crematogaster (subgenus Decacrema) ants inhabiting Macaranga myrmecophytes indicated that the partners diversified synchronously and their specific association has been maintained for 20 million years. However, the mtDNA clades did not exactly match morphological species, probably owing to introgressive hybridization among younger species. In this study, we determined the congruence between nuclear simple sequence repeat (SSR, also called microsatellite) genotyping and mtDNA phylogeny to confirm the suitability of the mtDNA phylogeny for inferring the evolutionary history of Decacrema ants. Analyses of ant samples from Lambir Hills National park, northeastern Borneo, showed overall congruence between the SSR and mtDNA groupings, indicating that mtDNA markers are useful for delimiting species, at least at the local level. We also found overall high host-plant specificity of the SSR genotypes of Decacrema ants, consistent with the specificity based on the mtDNA phylogeny. Further, we detected cryptic genetic assemblages exhibiting high specificity toward particular plant species within a single mtDNA clade. This finding, which may be evidence for rapid ecological and genetic differentiation following a host shift, is a new insight into the previously suggested long-term codiversification of Decacrema ants and Macaranga plants.