Driver Ants Invading a Termite Nest: Why Do the Most Catholic Predators of All Seldom Take This Abundant Prey?

Driver ants ( i.e. , epigaeic species in the army ant genus Dorylus , subgenus Anomma ) are among the most extreme polyphagous predators, but termites appear to be conspicuously absent from their prey spectrum and attacks by driver ants on termite nests have not yet been described. Here, we report a Dorylus ( Anomma ) rubellus attack on a colony of the fungus-growing termite Macrotermes subhyalinus that was observed during the dry season in a savannah habitat in Nigeria's Gashaka National Park. It was estimated that several hundred thousand termites (probably more than 2.4 kg dry mass) were retrieved. The apparent rarity of driver ant predation on Macrotermes nests may be explained by different habitat requirements, by the fact that these ants mostly forage aboveground, by efficient termite defense behavior and nest architecture that make entry into the nest difficult, and finally by driver ant worker morphology, which differs remarkably from that of subterranean Dorylus species that regularly invade and destroy termite colonies.     

Prey spectra of two swarm-raiding army ant species in East Africa

Although swarm-raiding army ants are considered keystone predators in tropical forest ecosystems, information on the prey spectra of most species is based on anecdotal reports and not on systematic studies with extensive sampling. We analysed prey samples of 18 colonies of the two afrotropical species Dorylus ( Anomma ) molestus and Dorylus ( Anomma ) wilverthi (4289 prey items in total) to examine the prey composition variation within and between species and to determine the best methodology to obtain reliable prey spectrum estimates for a given species, site and season. Variation in prey composition was substantial for D. molestus even within a single site and season, with the biomass proportion of the most important prey type differing by a factor of 12. Conclusions from studies using small samples sizes may thus be misleading. We demonstrate that the method of assessing prey spectra in terms of relative prey item numbers often produces biased results, and therefore recommend relative prey biomass as the more useful parameter. The near absence of earthworms, which always constituted a substantial part of the D. molestus prey, in the diet of D. wilverthi is interpreted to result from subtle differences in swarm-raiding behaviour between these two species, but could alternatively also be due to low availability. Similar studies recording prey composition as biomass proportions and analysing large samples sizes from many colonies are needed to understand the effect of army ant swarm raids on invertebrate communities in afrotropical forests.     

Temporal and spatial patterns in the emigrations of the army ant Dorylus (Anomma) molestus in the montane forest of Mt Kenya

Abstract.  1. The emigration behaviour of the army ant Dorylus ( Anomma ) molestus was studied in the montane forest of Mt Kenya. This species forages by massive swarm raids (mean width 10.3 m ± 4.6 m SD), which are assumed to have a strong negative impact on the densities of prey populations.
2. For non-reproductive colonies the stay duration in a nest is highly variable (median 17, range 3–111 days). This suggests that the frequency of emigrations is not dictated by a brood cycle as an underlying endogenous pattern generator.
3. Colony density is high (mean nearest neighbour's distance 82.1 m ± 29.4 m SD) and mean foraging range is 75.0 m, so encounters with neighbouring colonies occur frequently.
4. The straight line emigration distance is on average 92.7 m (± 29.7 SD). The emigration direction is random with respect to absolute bearing and also relative to the direction of the previous emigration. However, the emigration direction is influenced by the location of the nearest neighbour. Colonies typically emigrate directly away from their nearest neighbour.
5. Local food depletion is likely to be the ultimate cause for emigrations in this species, because emigration distance is larger than foraging range and colonies move away from their nearest neighbour. A small percentage of emigrations may be triggered by pangolin attacks on nests.
6. Contrary to the prediction of a recently developed mathematical model for epigaeic swarm-raiding Dorylus ( Anomma ) species, D.  ( A .)  molestus colonies do not engage in intraspecific battles. Possible reasons for the absence of fights between colonies despite apparently fierce intraspecific competition are discussed.     

Army ant prey availability and consumption by chimpanzees (Pan troglodytes vellerosus) at Gashaka (Nigeria)

Army ant predation by chimpanzees has been studied as an intriguing example of tool use and a possible case of cultural variation. However, the importance of army ant prey in chimpanzee diet and feeding ecology is still only poorly understood. We studied the availability and consumption of army ants in a population of the chimpanzee subspecies Pan troglodytes vellerosus in Nigeria. Army ants were collected from nests and trails (workers) and near artificial light sources (males). Three potential prey species were found: Dorylus rufescens, Dorylus gerstaeckeri and Dorylus kohli . Dorylus rufescens was by far more abundant than the other two species. Only remains from D. rufescens were present in chimpanzee faeces. This is the first report of consumption of this ant species by chimpanzees. However, because of the low availability of the other two species, it is unclear whether this pattern reflects a preference for D. rufescens . Although D. rufescens ' availability varied with weather conditions, the occurrence as well as the absolute and relative numbers of Dorylus fragments in faeces did not. This finding, together with the considerable difficulties encountered by human observers in their efforts to locate nests by following trails, suggests that the chimpanzees in this population do not harvest army ants from trails and do not use trails to locate nests. The overall occurrence of army ant fragments in 42.3% of all faecal samples is the highest ever recorded in any chimpanzee population. This indicates that in this chimpanzee population, army ant prey is not a fallback during periods of sparse availability of plant food, but quantitatively important throughout the year. Future studies will be needed to clarify which cues and strategies chimpanzees use to locate army ant nests and to assess the role of myrmecophagy with respect to macro- or micronutrient demands.     

A cladistic study of Arillastrum, Angophora and Eucalyptus (Myrtaceae)

A cladistic study of Anllastrum, Angophora and Eucalyptus (Myrtaceae). Transformed cladistic; character compatibility; branch and bound, and Farris-Wagner methods gave similar solutions in a cladistic study of Arillastrum, Angophora and Eucalyptus. These analyses, based on morphological characters, indicate that Eucalyptus is a monophyletic group and that its sister taxon is Angophora.
Within Eucalyptus , subgenera Blakella and Corymbia are sister taxa to all other groups; subgenera Monocalyptus, Idiogenes and Gaubaea form a monophyletic group with subgenus Monocalyptus sister to subgenera Idiogenes and Gaubaea ; subgenera Symphyomyrtus and Telocalyptus together also form a monophyletic group and, with Eucalyptus similis (subgenus Eudesmia group 4), are sister to the Monocalyptus group. Eucalyptus subgenus Telocalyptus (4 species), Eucalyptus subgenus Idiogenes (1 species) and Eucalyptus subgenus Gaubaea (2 species) should not be recognized as subgenera and some individual species need further examination. Eucalyptus subgenus Eudesmia is a paraphyletic group.
Some characters are identified as parallelisms, e.g. axillary inflorescences, sepaline operculum, bristle glands, and clustered anthers. A more congruent interpretation of the single operculum of Eucalyptus subgenus Monocalyptus as at least partly petaline rather than solely sepaline in origin is suggested.
The area relationships for the taxa are concordant with those derived from geological and climatological information. New Caledonia is sister area to Australia, and within Australia southwestern Australia is sister area to south-eastern and north-eastern Australia.     

Molecular phylogenetic relationships and the coevolution of placentotrophy and superfetation in Poecilia (Poeciliidae: Cyprinodontiformes)

Members of Poeciliidae are used as model organisms for experimental studies on natural and sexual selection, and comparative studies of life-history evolution. The latter have demonstrated multiple origins of both superfetation and placentotrophy within Poeciliidae. Most recently, placentotrophy has been described in five species of Poecilia (Pamphorichthys), but only one of these (P.hasemani) shows evidence of superfetation. Here, we use a molecular phylogeny based on concatenated nuclear and mitochondrial gene sequences to test hypotheses of correlated evolution between superfetation and placentotrophy in Poecilia. Taxon sampling included all species in the subgenera Micropoecilia and Pamphorichthys for which the presence or absence of placentotrophy and superfetation have been determined, as well as representatives of all other Poecilia subgenera (Acanthophacelus, Limia, Mollienesia, Poecilia, Pseudolimia). Phylogenetic analyses were performed with maximum parsimony, maximum likelihood, and Bayesian methods; ancestral states for life-history characters were reconstructed with parsimony and SIMMAP; correlation analyses were performed with SIMMAP; and divergence times were estimated using a relaxed molecular clock. All subgenera in Poecilia were recovered as monophyletic. The basal split in Poecilia is between P. (Acanthophacelus)+P. (Micropoecilia) and the other five subgenera. In the latter clade, P. (Poecilia) is the sister-group to the remaining four subgenera. Within P. (Pamphorichthys), all analyses with the combined data set recovered P. (Pamphorichthys) araguaiensis as the sister taxon to P. (Pamphorichthys) hollandi, and P. (Pamphorichthys) scalpridens as the sister taxon to P. (Pamphorichthys) minor. P. (Pamphorichthys) hasemani was either the sister taxon to P. (Pamphorichthys) hollandi+P. (Pamphorichthys) minor (maximum likelihood, Bayesian) or the sister taxon to all other Pamphorichthys species (maximum parsimony). Ancestral state reconstructions suggest that placentotrophy and superfetation evolved on the same branch in P. (Micropoecilia), whereas placentotrophy evolved before superfetation in P. (Pamphorichthys). SIMMAP analyses indicate a statistically significant association between placentotrophy and superfetation. Within P. (Micropoecilia) both placentotrophy and superfetation evolved in ≤4 million years. Within P. (Pamphorichthys), superfetation evolved in ≤9 million years on the P. (Pamphorichthys) hasemani branch, and placentotrophy evolved in ≤10 million years in the common ancestor of this subgenus.     

Male parentage in army ants

In most social insects workers do not mate, but have retained the ability to produce haploid eggs that can develop into viable male offspring. Under what circumstances this reproductive potential is realized and how the ensuing worker-queen conflict over male production is resolved, is an area of active research in insect sociobiology. Here we present microsatellite data for 176 males from eight colonies of the African army ant Dorylus (Anomma) molestus. Comparison with worker genotypes and inferred queen genotypes from the same colonies show that workers do not or at best very rarely reproduce in the presence of the queen. Queens of D. (A.) molestus are known to be highly multiply mated. This implies that workers are on average more closely related to queen sons than to other workers' sons, so that our results are consistent with predictions from inclusive fitness theory. It remains unknown, however, whether worker sterility is maintained by active worker policing or by self-restraint.     

Phylogenetic relationships among bumble bees (Bombus, latreille) inferred from mitochondrial cytochrome b and cytochrome oxidase I sequences

We conducted a molecular study intending to derive an estimate of the relationships within the genus Bombus (bumble bees) by comparing the mitochondrial cytochrome b and cytochrome oxidase I (COI) genes from 19 species, spanning 10 of approximately 16 European subgenera and 3 subgenera from North and South America. Our trees differ from the most recent classifications of bumble bees. Although bootstrap values for deep branches are low, our sequences show significant data structure and low homoplasy, and all trees share some groups and patterns. In all cases, the subgenus Bombus s. str. clusters among the most derived bumble bees, contrary to other molecular studies. In all trees, B. funebris is the sister taxon of B. robustus, and in five of the six trees, B. wurflenii is the sister taxon to this clade. B. nevadensis is basal to the other species in the analysis of the cytochrome b gene, but appears to be among the most derived according to the analysis of the COI region. The species representing the subgenera Thoracobombus and Fervidobombus are consistently among the earliest diverged. Species that appear in very different positions in different trees are B. nevadensis, B. mesomelas, B. balteatus, and B. hyperboreus. All subgenera with two representatives in our analysis are apparently monophyletic except Fervidobombus, Melanobombus, and Pyrobombus. The groups formed by pocket makers and non-pocket makers within Bombus also appear to be paraphyletic, and therefore some subgenera may not accurately reflect phylogeny.     

Tool use by wild chimpanzees in feeding upon driver ants

The use of stick tools by wild chimpanzees (Pan troglodytes) to feed upon driver ants (Dorylus (Anomma) nigricans) is described. Observations of this ant dipping were made over five years in the Gombe National Park in western Tanzania. Chimpanzees find the nomadic ant colonies visually, often re-visiting the subterranean nest sites until the ants move on. The nest is opened manually and tools are made from green woody vegetation. The ant dipping sequence is intricate and efficient. The chimpanzee predator uses several positioning strategies to minimise the ants' massed defensive tactics. Average intakes of 17–20 g/feeding session are estimated. It is concluded that ants may constitute a significant chimpanzee dietary component and that the dipping tools and techniques are relatively stereotyped in form.     

Molecular phylogeny and stripe pattern evolution in the cardinalfish genus Apogon

Cardinalfishes of the genus Apogon (Apogonidae) are one of the most speciose (>200 species) and numerically dominant fishes in coral reefs. Although the genus is divided into 10 subgenera, more than 70% of the species are included in the subgenus Ostorhinchus, most having either horizontal or vertical lines on the body. The phylogenetic relationship among 32 species of subgenus Ostorhinchus and 11 species of four other subgenera of Apogon, based on mitochondrially encoded 12S and 16S ribosomal genes and intervening tRNA(Val) gene, were investigated, using two species of the apogonid genus Fowleria as outgroups. The analyses demonstrated that Ostorhinchus (the most speciose subgenus) was polyphyletic, comprising at least three lineages, Ostorhinchus I, II, and III. Ostorhinchus I included two species, A. (O.) amboinensis and A. (O.) sangiensis, being a sister group to subgenus Zoramia. Ostorhinchus II and III included species with horizontal and vertical lines on the body, respectively. The respective monophylies of the latter two groups, together with a molecular clock calibration, indicated that in the evolutionary history of the genus, basic stripe patterns evolved first (more than 20 million years BP), with subsequent pattern diversification and modification.     

Protein variation and systematics of three subgenera of Malayan rats (Rodentia: Muridae, genus Rattus Fischer).

1. Nine erythrocyte proteins coded by a separate locus each were analysed in and among seven Malayan species of Rattus belonging to three subgenera. 2. Electrophoretic data obtained confirm the specific status of the seven taxa and divide the seven species into three groups which correspond with Ellerman's (1949) subgenera Stenomys, Maxomys and Leopoldamys. 3. A comparative study together with 11 other species of Malayan Rattus previously analysed show that, with few exceptions, the overall relationships among the 18 species based on electrophoretic data correspond well with conclusions based on morphological evidence. 4. Malayan species of Rattus are relatively very diverse genetically (S = 0.27, range 0.01-0.94).     

The nature of culture: technological variation in chimpanzee predation on army ants revisited

Chimpanzee (Pan troglodytes) predation on army ants (Dorylus, subgenus Anomma) is an impressive example of skillful use of elementary technology, and it has been suggested to reflect cultural differences among chimpanzee communities. Alternatively, the observed geographic diversity in army-ant-eating may represent local behavioral responses of the chimpanzees to the anti-predator traits of the army ant species present at the different sites. We examined assemblages of available prey species, their behavior and morphology, consumption by chimpanzees, techniques employed, and tool lengths at 14 sites in eastern, central, and western Africa. Where army ants are eaten, tool length and concomitant technique are a function of prey type. Epigaeically foraging species with aggressive workers that inflict painful bites are harvested with longer tools and usually by the "pull-through" technique; species foraging in leaf-litter with less aggressive workers that inflict less painful bites are harvested with short tools and by the "direct-mouthing" technique. However, prey species characteristics do not explain several differences in army-ant-eating between Bossou (Guinea) and Ta? (Ivory Coast), where the same suite of prey species is available and is consumed. Moreover, the absence of army-ant-eating at five sites cannot be explained by the identity of available prey species, as all the species found at these sites are eaten elsewhere. We conclude that some of the observed variation in the predator-prey relationship of chimpanzees and army ants reflects environmental influences driven by the prey, while other variation is not linked to prey characteristics and may be solely sociocultural.     

A molecular phylogeny of <Emphasis Type="Italic">Dorylus</Emphasis> army ants provides evidence for multiple evolutionary transitions in foraging niche

Background  

Army ants are the prime arthropod predators in tropical forests, with huge colonies and an evolutionary derived nomadic life style. Five of the six recognized subgenera of Old World Dorylus army ants forage in the soil, whereas some species of the sixth subgenus (Anomma) forage in the leaf-litter and some as conspicuous swarm raiders on the forest floor and in the lower vegetation (the infamous driver ants). Here we use a combination of nuclear and mitochondrial DNA sequences to reconstruct the phylogeny of the Dorylus s.l. army ants and to infer the evolutionary transitions in foraging niche and associated morphological adaptations.     

Molecular phylogenetics and biogeography provide insights into the subgeneric classification of Wiedemannia Zetterstedt (Diptera: Empididae: Clinocerinae)

The subgenera of Wiedemannia are poorly defined and, as such, most recently described species are not assigned to a subgenus or have been assigned to a subgenus without explanation. In this study we perform a molecular phylogenetic analysis to elucidate relationships within the genus Wiedemannia. We sequenced two mitochondrial (cytochrome oxidase c subunit I and cytochrome β) and two nuclear (carbomoylphosphate synthase domain of rudimentary and elongation factor‐1α) gene fragments to reconstruct phylogenetic relationships among the subgenera Chamaedipsia, Eucelidia, Philolutra, Pseudowiedemannia, Roederella and Wiedemannia (s.s.) using both Bayesian inference and maximum likelihood approaches. The genus was found to be monophyletic, but most of the subgenera were not. We propose eliminating the present subgeneric division altogether. Molecular dating using a log‐normal clock model and calibration with fossil species indicated that Wiedemannia diversified about 48 Ma, while there was still land connectivity between Europe and Asia with North America. Wiedemannia has a near‐worldwide distribution apart from the Australasian and Neotropical regions and Antarctica, with greatest species richness in the western Palaearctic, especially the Mediterranean region. Molecular phylogenetics support more recent morphological studies. The subgenera of Wiedemannia are invalid and rejected. Biogeographical data suggest potential hotspots, and the current distribution is discussed.     

Extreme queen-mating frequency and colony fission in African army ants

Army ants have long been suspected to represent an independent origin of multiple queen-mating in the social Hymenoptera. Using microsatellite markers, we show that queens of the African army ant Dorylus (Anomma) molestus have the highest absolute (17.3) and effective (17.5) queen-mating frequencies reported so far for ants. This confirms that obligate multiple queen-mating in social insects is associated with large colony size and advanced social organization, but also raises several novel questions. First, these high estimates place army ants in the range of mating frequencies of honeybees, which have so far been regarded as odd exceptions within the social Hymenoptera. Army ants and honeybees are fundamentally different in morphology and life history, but are the only social insects known that combine obligate multiple mating with reproduction by colony fission and extremely male-biased sex ratios. This implies that the very high numbers of matings in both groups may be due partly to the relatively low costs of additional matings. Second, we were able to trace recent events of colony fission in four of the investigated colonies, where the genotypes of the two queens were only compatible with a mother-daughter relationship. A direct comparison of male production between colonies with offspring from one and two queens, respectively, suggested strongly that new queens do not produce a sexual brood until all workers of the old queen have died, which is consistent with kin selection theory.     

Toward a better understanding of the infrageneric relationships in Cortinarius (Agaricales, Basidiomycota)

Research on the molecular systematics of Cortinarius, a species-rich mushroom genus with nearly global distribution, is just beginning. The present study explores infrageneric relationships using rDNA ITS and LSU sequence data. One large dataset of 132 rDNA ITS sequences and one combined da-taset with 54 rDNA ITS and LSU sequences were generated. Hebeloma was used as outgroup. Bayesian analyses and maximum-likelihood (ML) analyses were carried out. Bayesian phylogenetic inference performed equally well or better than ML, especially in large datasets. The phylogenetic analysis of the combined dataset with species representing all currently recognized subgenera recovered seven well-supported clades (Bayesian posterior probabilities BPP > 90%). These major clades are: /Myxacium s.l., /subg. Cortinarius, the /phlegmacioid clade (including the subclades /Phlegmacium and /Delibuti), the /calochroid clade (/Calochroi, /Ochroleuci and /Allutus), the /telamonioid clade (/Telamonia, /Orellani, /Anomali), /Dermocybe s.l. and /Myxotelamonia. Our results show that Cortinarius consists of many lineages, but the relationships among these clades could not be elucidated. On one hand, the low divergence in rDNA sequences can be held responsible for this; on the other hand, taxon sampling is problematic in Cortinarius phylogeny. Because of the incredibly high diversity (~2000 Cortinarius species), our sampling included <5% of the known species. By choosing type species of subgenera and sections, our sampling is strongly biased toward Northern Hemisphere taxa. More extensive taxon sampling, especially of species from the Southern Hemisphere, is essential to resolve the phylogeny of this important genus of ectomycorrhizal fungi.     

Evaluation of the apron as a taxonomic trait in ixodid ticks of the genus Dermacentor Koch (Ixodoidea, Ixodidae)

Study of the apron in 9 species of the genus Dermacentor from the fauna of the USSR has revealed differencies in its structure. The subgenus Dermacentor (s. str.) differs from two other subgenera both in the shape of the apron itself and in the shape of the postgenital sclerite and setae of perigenital area. Close species within each of two other subgenera differ in apron proportion, shape and size of denticles along its hind edge, and sometimes in their number. Inspite of the statistically reliable interspecific differences in apron structure a wide range of individual variability of some details and geographical specificity of samples from various places of the area were observed in species with a vast area.     

Genetic polymorphism in sympatric species of the genus Phlebotomus, with special reference to Phlebotomus perniciosus and Phlebotomus longicuspis (Diptera, Phlebotomidae)

The Random Amplified Polymorphic DNA assay was used to study genetic variation within and between five Phlebotomus species belonging to three subgenera: P. (Larroussius) ariasi, P. (L.) longicuspis, P. (L.) perniciosus, P.(Paraphlebotomus) sergenti and P. (Phlebotomus) papatasi sympatric in southern Spain and proven vector of leishmaniasis. Two cluster analysis were proposed: one according to sandfly species and populations, the second according individual specimens of Phlebotomus perniciosus, Phlebotomus longicuspis s.l. and intermediate morphological specimens between these species. The results obtained are closely correlated with the taxonomy classically accepted for the subgenera and with the automatic classifications made by other authors which use morphological and isoenzymatic data. The validity of the species Phlebotomus longicuspis is also discussed.