Isolation and characterization of polymorphic microsatellites in the tropical plant‐ant Cataulacus mckeyi (Formicidae: Myrmicinae)

Eleven microsatellite loci were isolated from the plant‐ant Cataulacus mckeyi (Hymenoptera: Myrmicinae) and their polymorphism was characterized. High levels of within‐population variation were observed at most loci, with number of alleles ranging from one to 16, and heterozygosity from 0 to 0.929 per population sample. Cross‐species amplification of these loci was also tested in four other species of the ant genus Cataulacus.     

PCR primers for polymorphic microsatellite loci in the plant‐ant Azteca ulei cordiae (Formicidae: Dolichoderinae)

Twelve microsatellite loci were isolated from the Peruvian tropical plant‐ant, Azteca ulei cordiae (Hymenoptera: Dolichoderinae). High levels of within‐population variation were observed at most loci, with number of alleles ranging from four to 18, and heterozygosity from 0.118 to 1 per population sample. Cross‐species amplification of these loci was also successfully tested in several other species of the same ant genus Azteca.     

PCR primers for polymorphic microsatellite loci in the facultatively polygynous plant‐ant Petalomyrmex phylax (Formicidae)

Fourteen microsatellite loci were isolated and their level of polymorphism characterized in two populations of the facultatively polygynous plant‐ant Petalomyrmex phylax (Formicinae). High levels of within‐population variation were observed at most loci, with number of alleles ranging from two to 15, and heterozygosity from 0.050 to 0.925. Cross‐species amplification of these loci was also tested in four plant‐ant species belonging to three other genera, Aphomomyrmex, Cladomyrma (both Formicinae) and Cataulacus (Myrmicinae).     

Impact of the invasive ant Wasmannia auropunctata (Formicidae: Myrmicinae) on local ant diversity in southern Cameroon

The little fire ant, Wasmannia auropunctata Roger, is one of the world's most destructive invasive ants. It has been present in Cameroon for more than four decades, but its impact on local ant diversity is not known. We studied impact of W. auropunctata in three disturbed habitats located in rural and urban areas. We monitored ant diversity in both invaded and noninvaded zones in each area using a combination of three sampling methods: bait, pitfall traps and visual catch in quadrat. We collected 28 species in urban area and 64 in rural area. In invaded zone, W. auropunctata made up 97.72% and 99.96% of all ant fauna and ant species richness decreased to 7 and 2 in urban and rural area, respectively. In accordance with others findings in introduced environments, the presence of W. auropunctata has severely reduced abundance and richness of local ant species in both urban and rural environments in Cameroon. Measures should therefore be put in place to prevent its introduction in natural environment as forest reserves and natural parks.     

Polymerase chain reaction primers for polymorphic microsatellite loci in the ant Pseudomyrmex gracilis (Formicidae: Pseudomyrmecinae)

The elongate twig ant Pseudomyrmex gracilis is widely distributed in the New World ranging from southern USA to Brazil and northern Argentina. To investigate its within-colony relatedness, we developed primers for nine polymorphic microsatellite loci. High levels of within-population variation were observed, with number of alleles ranging from two to 13, and heterozygosity from 0.28 to 0.90. The loci showed no deviations from Hardy-Weinberg equilibrium and no linkage disequilibrium.     

Five polymorphic microsatellite markers for the study of Cardiocondyla elegans (Hymenoptera: Myrmicinae)

We describe primer sequences for five microsatellite markers in Cardiocondyla elegans, an ant species with ergatoid males. Polymorphism of these loci was investigated using 236 individuals from 22 colonies from four locations. The microsatellites are dinucleotide repeats with four to 16 alleles, and the observed heterozygosity ranges from 0.244 to 0.720. We characterized these markers for the study of the population as well as the social structure of colonies.     

Characterization of polymorphic microsatellite loci in the red harvester ant,Pogonomyrmex barbatus

The red harvester ant, Pogonomyrmex barbatus, is a monogynous, polyandrous species: each ant colony is founded by a single queen that has mated with one or more males. To study levels of polyandry within a colony, as well as relationships among colonies, we developed 10 polymorphic microsatellite loci for P. barbatus. With the number of alleles per locus ranging from 3 to 39, and expected heterozygosities of 0.58–0.95, these markers promise to be useful in the study of colony and population genetic structure.     

切叶蚁亚科七属十二种的分子系统学研究

测定了切叶蚁亚科7属12种的线粒体CO1、CO2的部分基因及完整的tRNA_Leu基因DNA序列,对DNA序列进行了分析,对tRNA_Leu 基因进行了二级结构分析;根据DNA序列数据和氨基酸序列数据,以臭蚁亚科的Forelius chalybaeus作为外群,采用最大似然法(ML)、最大简约法(MP)、邻接法(NJ)、未加权组对算术平均法(UPGMA)构建分子系统树,通过自举检验,得到自举置信水平,以此检验该分子系统树的可靠性。研究结果显示,基于以上基因的分子系统分析与传统分类分析的结果基本一致,且在属级的一致性高于种级的一致性。     

Trees to treehoppers: genetic variation in host plants contributes to variation in the mating signals of a plant‐feeding insect

Community genetics research has demonstrated ‘bottom‐up’ effects of genetic variation within a plant species in shaping the larger community with which it interacts, such as compositions of arthropod faunas. We demonstrate that such cross‐trophic interactions also influence sexually selected traits. We used a member of the Enchenopa binotata species complex of treehoppers (Hemiptera: Membracidae) to ask whether male mating signals are influenced by host plant genetic variation. We reared a random sample of the treehoppers on potted replicates of a sample of host plant clone lines. We found that treehopper male signals varied according to the clone line on which they developed, showing that genetic variation in host plants affects male treehoppers' behavioural phenotypes. This is the first demonstration of cross‐trophic indirect genetic effects on a sexually selected trait. We discuss how such effects may play an important role in the maintenance of variation and within‐population phenotypic differentiation, thereby promoting evolutionary divergence.     

Root volatiles in plant–plant interactions II: Root volatiles alter root chemistry and plant–herbivore interactions of neighbouring plants

Volatile organic compounds (VOCs) emitted by plant roots can influence the germination and growth of neighbouring plants. However, little is known about the effects of root VOCs on plant–herbivore interactions of neighbouring plants. The spotted knapweed (Centaurea stoebe) constitutively releases high amounts of sesquiterpenes into the rhizosphere. Here, we examine the impact of C. stoebe root VOCs on the primary and secondary metabolites of sympatric Taraxacum officinale plants and the resulting plant‐mediated effects on a generalist root herbivore, the white grub Melolontha melolontha. We show that exposure of T. officinale to C.stoebe root VOCs does not affect the accumulation of defensive secondary metabolites but modulates carbohydrate and total protein levels in T. officinale roots. Furthermore, VOC exposure increases M. melolontha growth on T. officinale plants. Exposure of T. officinale to a major C. stoebe root VOC, the sesquiterpene (E)‐β‐caryophyllene, partially mimics the effect of the full root VOC blend on M. melolontha growth. Thus, releasing root VOCs can modify plant–herbivore interactions of neighbouring plants. The release of VOCs to increase the susceptibility of other plants may be a form of plant offense.     

Determinants of intracolonial relatedness in Pogonomyrmex rugosus (Hymenoptera; Formicidae): mating frequency and brood raids

The genus Pogonomyrmex is one of three ant genera with an effective mating frequency (me) > 2.0. We developed microsatellites to determine me for P. rugosus because mating frequency of P. rugosus was known only from observational data which do not allow an estimate of me. We genotyped 474 workers from 20 colonies for two microsatellite loci. Observed mating frequencies ranged from 3 to 12 and me for P. rugosus was 4.71. Observed patriline frequencies were significantly different from the expected patriline frequencies generated with a simulated data set under the assumption of equal patriline representation. The available mating frequency data and phylogenetic information of the genus Pogonomyrmex suggest that multiple mating is the ancestral state in the North American Pogonomyrmex sensu stricto. Established P. rugosus colonies raid and destroy smaller conspecific colonies. During these raids ant workers were observed carrying pupae and larvae from the raided colony into the nest of the raiding colony. However, it was not clear whether raided brood emerged in the raiding colony and were subsequently recruited into the work force (intraspecific slavery) or were used as food (predation). Our analyses indicate 6 of 14 field colonies contained foreign P. rugosus workers (43%). The range of the intracolonial frequency of foreign workers collected directly from the nest entrance was between 4 and 28%.     

Molecular phylogeny of the ant tribe Myrmicini (Hymenoptera: Formicidae)

The interrelationships within ant subfamilies remain elusive, despite the recent establishment of the phylogeny of the major ant lineages. The tribe Myrmicini belongs to the subfamily Myrmicinae, and groups morphologically unspecialized genera. Previous research has struggled with defining Myrmicini, leading to considerable taxonomic instability. Earlier molecular phylogenetic studies have suggested the nonmonophyly of Myrmicini, but were based on limited taxon sampling. We investigated the composition of Myrmicini with phylogenetic analyses of an enlarged set of taxa, using DNA sequences of eight gene fragments taken from 37 representatives of six of the seven genera (Eutetramorium, Huberia, Hylomyrma, Manica, Myrmica, and Pogonomyrmex), and eight outgroups. Our results demonstrate the invalidity of Myrmicini as currently defined. We recovered sister‐group relationships between the genera Myrmica and Manica, and between Pogonomyrmex and Hylomyrma. This study illustrates that to understand the phylogeny of over 6000 myrmicine species, comprehensive taxon sampling and DNA sequencing are an absolute requisite. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 482–495.     

Landscape heterogeneity shapes host‐parasite interactions and results in apparent plant–virus codivergence

Knowledge on how landscape heterogeneity shapes host–parasite interactions is central to understand the emergence, dynamics and evolution of infectious diseases. However, this is an underexplored subject, particularly for plant–virus systems. Here, we analyse how landscape heterogeneity influences the prevalence, spatial genetic structure, and temporal dynamics of Pepper golden mosaic and Pepper huasteco yellow vein begomoviruses infecting populations of the wild pepper Capsicum annuum glabriusculum (chiltepin) in Mexico. Environmental heterogeneity occurred at different nested spatial scales (host populations within biogeographical provinces), with levels of human management varying among host population within a province. Results indicate that landscape heterogeneity affects the epidemiology and genetic structure of chiltepin‐infecting begomoviruses in a scale‐specific manner, probably related to conditions favouring the viruses' whitefly vector and its dispersion. Increased levels of human management of the host populations were associated with higher virus prevalence and erased the spatial genetic structure of the virus populations. Also, environmental heterogeneity similarly shaped the spatial genetic structures of host and viruses. This resulted in the congruence between host and virus phylogenies, which does not seem to be due to host‐virus co‐evolution. Thus, results provide evidence of the key role of landscape heterogeneity in determining plant–virus interactions.     

Characterization of polymorphic microsatellites in the Pacific sardine Sardinops sagax sagax (Clupeidae)

We isolated 11 microsatellites from the Pacific sardine Sardinops sagax sagax. The number of alleles and H_E among 30 individuals from a single population ranged from four to 24 and from 0.606 to 0.959, respectively. Pacific sardines are a vital economic resource in the northeastern Pacific Ocean, but insufficiently polymorphic loci have limited inferences about its stock structure and genetic variation. The level of variability of these new markers will prove useful in testing hypotheses on the stock‐structure and long‐term genetic integrity of the species.     

Seeing through the static: the temporal dimension of plant–animal mutualistic interactions

Most studies of plant–animal mutualistic networks have come from a temporally static perspective. This approach has revealed general patterns in network structure, but limits our ability to understand the ecological and evolutionary processes that shape these networks and to predict the consequences of natural and human‐driven disturbance on species interactions. We review the growing literature on temporal dynamics of plant–animal mutualistic networks including pollination, seed dispersal and ant defence mutualisms. We then discuss potential mechanisms underlying such variation in interactions, ranging from behavioural and physiological processes at the finest temporal scales to ecological and evolutionary processes at the broadest. We find that at the finest temporal scales (days, weeks, months) mutualistic interactions are highly dynamic, with considerable variation in network structure. At intermediate scales (years, decades), networks still exhibit high levels of temporal variation, but such variation appears to influence network properties only weakly. At the broadest temporal scales (many decades, centuries and beyond), continued shifts in interactions appear to reshape network structure, leading to dramatic community changes, including loss of species and function. Our review highlights the importance of considering the temporal dimension for understanding the ecology and evolution of complex webs of mutualistic interactions.     

Phenological phases of the host plant shape plant–treehopper interaction networks

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Army ant behaviour in the poneromorph hunting ant Onychomyrmex hedleyi Emery (Hymenoptera: Formicidae; Amblyoponinae)

Onychomyrmex belongs to the phylogenetically basal ant tribe Amblyoponini but shows prototypical army ant behaviours, i.e. group predation and nomadism. In order to investigate these behaviours, Onychomyrmex hedleyi was observed in the field and in laboratory experiments. Workers of O. hedleyi would frequently hunt centipedes but rarely social insects. Workers did not dismember the victims but recruited the colony mates to conduct group retrieval. If the prey were too large or too heavy to retrieve, the entire colony moved from the bivouac site to the prey site. Although foraging on the forest floor, a colony repeated the extension and withdrawal of a raiding column, which was up to 80 cm long (mean ± SD, 41.6 ± 18.5 cm). Colonies were nomadic and the relocation distance was up to 150 cm (mean ± SD, 74.4 ± 45.0 cm). Retinues guarded a queen who moved to a new bivouac site in the early phase of relocation. Colonies were found to stay at a site statistically longer if they had come from a more distant site, and were also observed to move to a more distant site if they had spent a longer time at a particular bivouac site. The consecutive migrations did not show significant directionality.     

A new record ant species of the genus Cardiocondyla Emery from China(Hymenoptera: Formicidae)

An ant species, Cardiocondyla gibbosa Kuznetzov-Ugamsky, 1927, is newly recorded from China. The specimens were collected from Shule County of Kashgar, Xinjiang(39°14′N, 76° 22′E; elev. 1 248 m). All the specimens are kept in Institute of Zoology, Shaanxi Normal University. A key based on worker caste to known species of Cardiocondyla from China is provided.     

Anthropogenic disturbance and rainfall variation threaten the stability of plant–ant interactions in the Brazilian Caatinga

Climate change is projected to exacerbate the effects of anthropogenic disturbance, with negative impacts on ecosystem stability and functioning. We evaluate the additive and combined effects of chronic anthropogenic disturbance (CAD) and rainfall variation on the temporal stability of mutualistic EFN‐bearing plant–ant networks in a Caatinga dry forest. We evaluated whether changes in the stability of these interactions are driven by changes in the stability of the communities of partners involved and/or in ant behavior. We sampled EFN‐bearing plant–ant networks in sixteen 20 × 20 m plots distributed across CAD and rainfall gradients. The stability of EFN‐bearing plant and attendant–ant communities were measured as the inverse of temporal differences in their community structure and composition. We also computed the stability of EFN‐bearing plant–ant networks by measuring the inverse of temporal differences in network specialization metrics. We found that, in general, the structure and composition of plant and ant interacting communities were similarly stable along both environmental gradients. Only CAD and its interaction with rainfall affected the temporal stability of EFN‐bearing plant diversity, which declined as CAD increased, with a more pronounced relationship in wetter areas. However, variation in levels of CAD and, to a lesser extent, rainfall greatly modulated the stability of EFN‐bearing plant–ant network specialization. CAD reduced the stability of network generality (specialization at the ant level), an effect that was much stronger in wetter areas. Meanwhile, the stability in network vulnerability (specialization at the plant level) decreased with the increase of CAD and the decrease of rainfall levels. Finally, there was a trend of decreasing stability in specialization of the overall network with increasing CAD. Our results suggest that changes in the structure of interaction networks are mainly driven by a switch in ant behavior rather than by changes in the structure and composition of plant and ant communities between years.