Nest architecture of the leaf-cutting ant <Emphasis Type="Italic">Acromyrmex rugosus rugosus</Emphasis>

The prominent nests mounds of many ant species are one of the most obvious signs of their presence, yet the subterranean architecture of nests is often poorly known. The present work aimed to establish the external and internal structure of nests of a species of leaf-cutting ant, Acromyrmex rugosus rugosus, by either marking the interior of nests with talcum powder, or forming casts with cement. Twelve nests were excavated and surveyed, with eight being marked with talcum powder and four cast with cement. The external and internal structure of the nests was highly variable. The largest and smallest nests had mound areas of 9.89 m² and 0.01 m² respectively. The number of chambers found ranged from 1 to 26, with maximum dimensions of between 6 and 70 cm. Chambers were found close to the soil surface (6 cm) down to a maximum depth of 3.75 m. In addition to chambers containing fungus garden, some chambers were found to be empty, filled with soil or filled with waste, the first time this has been recorded in a species of Acromyrmex. The nests of A. rugosus rugosus appear to be unusually complex for the genus, containing a diversity of irregular chambers and tunnels. Received 21 December 2006; revised 30 May 2007; accepted 1 June 2007.     

The nest architecture of the ant, Pheidole oxyops Forel, 1908 （Hymenoptera： Formicidae）

Pheidole oxyops builds subterranean nests, with an external architecture that is distinctive and easily recognizable by its wide and specific entrance hole, measuring up to 12.2 cm in diameter, denoting a pitfall-trap. In order to study the nests＇ internal architecture, seven nests were excavated; four were identified with neutral talc, while the others were cast in cement and then excavated. Measurements were made in order to gain a better understand- ing of their structures, and a photographic documentation was obtained as well. The excavations revealed that the nests are perpendicular relative to the ground, beginning with a cylindrical channel with a mean length of 13.5 cm, containing irregular formations, and whose diameter becomes progressively narrower until the first chamber is formed. As the channel continues, dish-like chambers appear, interconnected by channels that become progressively narrower and longer, while the chambers are arranged at greater distances from each other as nest depth increases. Both channels and chambers are located on the vertical projection of the entrance hole. Nests may reach a depth of up to 5.09 m, with a number of chambers ranging between 4 and 14.     

Nest architecture of the ant <Emphasis Type="Italic">Formica pallidefulva</Emphasis>: structure,costs and rules of excavation

Summary The architecture of underground ant nests was studied in the ant Formica pallidefulva. These ants build shallow (30–45 cm deep) nests, which consist of more or less vertical shafts that bear chambers. Shafts are modular units of nest growth; nests are enlarged by adding more shafts or extending previously existing ones. The nests are top-heavy, their volume declining exponentially with depth. The total volume of the nest is strongly correlated with the number of worker occupying the nest (R² = 0.87). Some of the rules and templates used by workers for nest construction were determined: (a) chambers are formed in the direction of the tunnels leading up to them, (b) the amount of soil excavated per unit time increases with soil temperature and moisture content. The amount of time and energy required to construct a typical nest were approximated using digging ability parameters determined in the lab. We estimate that if a colony was to move twice a year, it would expend around 20% of its energy intake and at least 6% of its worker time on nest excavation.Received 16 December 2002; revised 10 July 2003; accepted 23 July 2003.     

The effect of environmental factors on the nesting and courtship behaviour ofTilapia zillii in Lake Kinneret (Israel)

Tilapia zillii is a polyphilic, guarding nest spawner which is widespread in west and north Africa and in the Middle East. A study of the nesting and courtship behaviour of this species in Lake Kinneret (Sea of Galilee), revealed that nesting and brood care differ according to the exposure of the nesting site to wave action and the nature of the substrate. The nests are simple and parental care is abbreviated in exposed, sandy sites whereas elaborate nests with brood chambers are excavated in sheltered areas with clayey substrates, and parental care is extensive. The implications of these findings to studies on cichlid breeding and the conservation ofT. zillii in Lake Kinneret are discussed.     

Nest architecture and colony size of the fungus-growing ant <Emphasis Type="Italic">Mycetophylax simplex</Emphasis> Emery, 1888 (Formicidae,Attini)

Detailed measurements on nest architecture and colony size of the fungus-growing ant Mycetophylax simplex Emery, 1888 (Formicidae, Attini) are reported for the first time, based on excavations of 55 nests from two sites in southern Brazil. All nests were subterranean, with a single entrance hole. Most nests consisted of two chambers, an upper and a lower chamber, but one and three-chamber nests were also found. The chambers were more cone-shaped than rounded, and located at a depth ranging from 4.0 cm to 32.5 cm below the nest entrance. The chamber dimensions generally increased as the depth of the chambers increased, and the lower chamber was mostly wider than the upper one. The fungus garden was always found resting on the chamber floor. The average colony size was 264.1 workers, ranging from 67 to 610 workers. Colonies produced most sexuals during the summer (from December to March) and a few during the winter (July). Direct observations showed that colonies were mostly monogynous, but more than one queen was recorded in two nests, suggesting that polygyny may also occur in this species. Received 30 November 2006; revised 20 April 2007; accepted 23 April 2007.     

Interaction between ants and fruits of<Emphasis Type="Italic"> Guapira opposita</Emphasis> (Nyctaginaceae) in a Brazilian sandy plain rainforest: ant effects on seeds and seedlings

This study examines the dispersal system of Guapira opposita in a tropical sandy rainforest in southeast Brazil. Guapira trees produce small fruits with a high protein content (28.4%) and low lipid content (0.3%), and the plant is primarily dispersed by birds. Mature fruits of G. opposita can fall spontaneously with the pulp intact, or be dropped by birds with bits of pulp attached. In either case, ground-dwelling ants rapidly remove the fruits to their nest (93% after 12 h). The ponerine ants Odontomachus chelifer and Pachycondyla striata are the main seed vectors among the ants, and together account for 56% (20 of 36) of the ant-fruit interactions recorded on the forest floor. Individual workers of O. chelifer and P. striata transport single fruits to their nests. Bits of pulp are fed to larvae and worker nestmates, and intact seeds are discarded outside the nest. Germination success in Guapira is higher for cleaned seeds (pulp removed) than for seeds coated by pulp. Guapira seedlings and juveniles are more frequent close to Odontomachus nests than at sites without such nests. Soil samples from Odontomachus nests had greater penetrability, and higher concentrations of P, K, and Ca than random soil samples. Field experiments suggest that the association between G. opposita seedlings and O. chelifer nests can potentially render the plant some protection against herbivores. Results indicate that fruit displacement by ponerine ants play an important role in the biology of G. opposita seeds and seedlings in the sandy forest, and illustrate the complex nature of the dispersal ecology of tropical tree species.     

Secondary seed dispersal by ants in Neotropical cerrado savanna: species‐specific effects on seeds and seedlings of Siparuna guianensis (Siparunaceae)

1. Most woody plant species in tropical habitats are primarily vertebrate‐dispersed, but interactions between ants and fallen seeds and fruits are frequent. This study assesses the species‐specific services provided by ants to fallen arillate seeds of Siparuna guianensis, a primarily bird‐dispersed tree in cerrado savanna. The questions of which species interact with fallen seeds, their relative contribution (versus vertebrates) to seed removal, and the potential effects on seedling establishment are investigated. 2. Seeds are removed in similar quantities in caged and control treatments, suggesting that ants are the main dispersers on the ground. Five ant species attended seeds. Pheidole megacephala (≈0.4 cm) cooperatively transported seeds, whereas the smaller Pheidole sp. removed the seed aril on spot. Large (> 1.0 cm) Odontomachus chelifer, Pachycondyla striata, and Ectatomma edentatum individually carried seeds up to 4 m. Bits of aril are fed to larvae and intact seeds are discarded near the nest entrance. 3. Overall, greater numbers of seedlings were recorded near ant nests than in control plots without nests. This effect, however, was only detected near P. megacephala and P. striata nests, where soil penetrability was greater compared with controls. Soil nutrients did not differ between paired plots. 4. This study confirms the prevalence of ant–seed interactions in cerrado and shows that ant‐derived benefits are species‐specific. Ant services range from seed cleaning on the spot to seed displacement promoting non‐random spatial seedling recruitment. Although seed dispersal distances by ants are likely to be shorter than those by birds, our study of S. guianensis shows that fine‐scale ant‐induced seed movements may ultimately enhance plant regeneration in cerrado.     

Biological notes on a fungus-growing ant, Trachymyrmex cf. zeteki (Hymenoptera, Formicidae, Attini) attacked by a diverse community of parasitoid wasps (Hymenoptera, Diapriidae)

A number of wasps in the family Diapriidae, subfamily Diapriinae (Proctotrupoidea), are parasitoids that specialize on ant larvae. These wasps are abundant and diverse in the Neotropics, but little is known about their biology. We studied parasitism rates by an array of diapriine wasps that attack the larvae of fungus-growing ants, Trachymyrmex cf. zeteki, in a single population (near Gamboa, Panamá). Relatively little is known about the biology and natural history of these ants, so we also present data on colony size and nest architecture. We excavated 136 colonies in central Panamá from June to September 2006, and 20 nests from July 2009. We reared six wasp morphotypes; two of them in the genus Mimopriella Masner and Garcia, one Oxypria Kieffer, two Szelenyiopria Fabritius and one Acanthopria Ashmead. The mean intensity of larval parasitism per ant colony was 33.9% (2006), and its prevalence across all ant populations was 27.2% (2006 and 2009). Parasitism rates were not positively correlated with host colony size. A single case of super-parasitism was documented in which two Oxypria males were reared from the same host larva.     

Nematodes from saline and freshwater lakes of the Vestfold Hills,East Antarctica,including the description of <Emphasis Type="Italic">Hypodontolaimus antarcticus</Emphasis> sp. n.

The invertebrate fauna of many Antarctic ice-free areas, even those close to permanent research stations, can be poorly known. Here we describe some nematodes from freshwater and saline, marine-derived lakes of the Vestfold Hills, East Antarctica. The freshwater lakes contained the widespread East Antarctic endemic species, Plectus frigophilus Kirjanova, 1958. The saline lakes were inhabited by two recently described species, Halomonhystera halophila Andrássy, 2006 and Halomonhystera continentalis Andrássy, 2006, and by a new species described in this report, Hypodontolaimus antarcticus sp. n. Originally marine but now brackish Highway Lake contained a nematode fauna with both freshwater and marine-derived components. The nematode fauna of Antarctica now consists of 54 named species, 22 of which are found in East Antarctica.     

Effects of forest loss and fragmentation on pollen diets and provision mass of the mason bee,Osmia cornifrons,in central Japan

1. Habitat loss and fragmentation potentially affect the performance of bees that forage nectar and pollen of plants in their habitats. In forest landscapes, silvicultural conifer plantations often have reduced and fragmented natural broadleaf forests, which seem to provide more floral resources for bees than do the plantations. 2. This study evaluated the effects of forest characteristics (i.e. elevation, area, edge length, and tree size of natural forests) on pollen diets (plant taxa assemblages of pollen grains in provisions) and total provision mass in oviposited chambers in nests made by a standardised number of Osmia cornifrons bees at 14 sites in a forestry area in central Japan. 3. From April to May, the numbers of nests and chambers per nest increased, and the provision mass per chamber decreased. Main pollen sources were Prunus at higher elevations in April and Wisteria at lower elevations in May, foraging on which increased the numbers of nests and chambers per nest. The provision mass per chamber was smaller at higher elevations in more fragmented natural forests. Decreases in the area of natural forests within the foraging range (400‐m radii) of O. cornifrons increased the utilisation of Rubus pollen and decreased the total provision mass. 4. These findings suggest that the loss and fragmentation of natural broadleaf forests change pollen diets and reduce the provision mass of mason bees, which may reduce the number and size of their offspring.     

New Miocene scarabeid and hymenopterous nests and early miocene (santacrucian) paleoenvironments,patagonian Argentina

Three new trace fossils are described from Miocene paleosols of southern Argentina. Celliforma pinturensis, n. ichnosp. and Celliforma rosellii, n. ichnosp. are interpreted as cells of digging bees, possibly Anthophoridae, and Coprinisphaerafrenguellii, n. ichnosp. are brood balls of dung‐beetles. Both burrowing bees and dung‐beetles are common nesters in relatively open areas, confirming previous reconstructions of the paleoenvironment of the Pinturas Formation. A brief review of scarabeid and bee fossil nests from South America is presented, and we propose that constructed nests have a higher preservation potential than excavated nests. This fact explains their more common occurrences as trace fossils in paleosols. A new ethological category, calichnia, is proposed for hymenopterous and coleopterous traces, in which adult individuals make nests exclusively for larvae.     

An analysis of the nesting behaviour of Geotrupes spiniger Marsham (Coleoptera, Scarabaeidae)

Abstract. 1. Female G.spiniger adults working alone made nests each consisting of a vertical shaft leading to a series of horizontal brood chambers filled with dung brood masses. Oviposition near the tip of the brood mass occurred while the egg cell was being completed over the expanded ovipositor. The shaft above each brood mass was filled with soil excavated from the next brood chamber. A similar response also filled artificial diverticula. An avoidance reaction towards buried dung prevented damage to pre-existing brood masses. 2. Virgin females did not make nests and did not avoid buried dung, but after mating (at about 4 weeks after eclosion) both types of behaviour were released within a few hours. 3. The presence of dung was required to initiate but not to maintain nesting behaviour. If dung was removed after oviposition the chamber was filled with soil produced by renewed excavation. Cellulose pulp could substitute for dung in brood mass formation. 4. Beetles interchanged between burrows at different stages before oviposition readily repeated all pre-oviposition behaviour. They appeared to respond to the length of the shaft and of the brood chamber since they extended short shafts and short brood chambers considerably more than those of normal length. After oviposition the beetles continued to make brood masses even under abnormal conditions. 5. Tilting the cage through 90° caused beetles before oviposition to re-orientate their burrowing direction, but tilting just after oviposition caused them to make vertical brood masses. Placing the shaft in a horizontal position towards the end of brood mass formation postponed the termination of this phase. 6. Beetles repeatedly excavated shafts and chambers when transferred to new cages. Conversely they repeatedly made brood masses when maintained in preformed plaster-of-Paris burrows. 7. This nesting behaviour can be described as a reaction chain in which each action generates its own terminating stimulus and initiates the subsequent response. The behaviour before oviposition could be omitted or repeated as required by the environment, but after oviposition there was little response to external interference. These characteristics have direct relevance to the survival of the larvae.     

Asymmetrical competition and amensalism through soil dumping by the ant, Myrmicaria natalensis

ABSTRACT.

• 1 Myrmicaria natalensis (Smith) (Hym: Formicidae) is a large, predaceous ant that excavates large amounts of soil during nest construction.
• 2 During the winter, 25% of its nests went extinct through resistance and aggression from allospecific ants. The remaining 75% thrived, although one nest was forced to move, but did not go extinct, through intense competition.
• 3 The surviving fifteen M.natalensis nests obliterated forty-one allospecific nests by covering them with excavated soil.
• 4 During spring, M.natalensis nests expanded rapidly and none went extinct, so there was no longer asymmetrical competition but total amensalism in favour of M.natalensis.
• 5 Implications for ant management are that control by trunk banding of honeydew-seeking ants will increase asymmetry towards M.natalensis through positive feedback. This is desirable in that M.natalensis is a highly predaceous ant of pests such as lepidopteran larvae.

     

PRASINOPHYTES FORM INDEPENDENT LINEAGES WITHIN THE CHLOROPHYTA: EVIDENCE FROM RIBOSOMAL RNA SEQUENCE COMPARISONS1

Complete nuclear-encoded small-subunit ribosomal RNA (rRNA) sequences were determined from Nephroselmis olivacea Stein, Pseudoscourfieldia marina (Throndsen) Manton, Scherffelia dubia (Perty) Pascher, and Tetraselmis striata Butcher (Chlorophyta) to investigate the evolutionary position of these scaly green flagellates. Results of neighbor-joining and maximum parsimony phylogenetic analyses demonstrate at least two independent prasinophyte lineages defined by N. olivacea/P. marina and S. dubia/T. striata, which together with the Chlorophyceae, Pleurastrophyceae, and Ulvophyceae form a monophyletic group. Within this assemblage, N. olivacea and P. marina represent an early-diverging lineage that is evolutionarily distinct from the later-diverging S. dubia/T. striata clade. The branch point of the S. dubia/T. striata clade precedes the near-simultaneous radiation of the Chlorophyceae, Ulvophyceae, and Microthamniales. Though interrelationships between these three latter groups of algae are not resolved, the phylogenetic analyses demonstrate that the Prasinophyceae (sensu Moestrup and Throndsen) and the Pleurastrophyceae (sensu Mattox and Stewart) are not monophyletic classes.     

Nest destruction elicits indiscriminate con‐ versus heterospecific brood parasitism in a captive bird

Following nest destruction, the laying of physiologically committed eggs (eggs that are ovulated, yolked, and making their way through the oviduct) in the nests of other birds is considered a viable pathway for the evolution of obligate interspecific brood parasitism. While intraspecific brood parasitism in response to nest predation has been experimentally demonstrated, this pathway has yet to be evaluated in an interspecific context. We studied patterns of egg laying following experimental nest destruction in captive zebra finches, Taeniopygia guttata, a frequent intraspecific brood parasite. We found that zebra finches laid physiologically committed eggs indiscriminately between nests containing conspecific eggs and nests containing heterospecific eggs (of Bengalese finches, Lonchura striata vars. domestica), despite the con‐ and heterospecific eggs differing in both size and coloration. This is the first experimental evidence that nest destruction may provide a pathway for the evolution of interspecific brood parasitism in birds.     

The erection of Pelecanema n. g. (Nematoda: Spirurida: Acuariidae), with redescriptions of P. sirry (Khalil, 1931) n. comb. and P. pelecani (Johnston & Mawson, 1942) n. comb.

Pelecanema n. g. is erected for P. sirry (Khalil, 1931) n. comb., syn. Synhimantus sirry Khalil, 1931 (type-species) and P. pelecani (Johnston & Mawson, 1942) n. comb., syn. Dispharynx pelecani Johnston & Mawson, 1942. In the structure of its cordons, consisting of two rows of delicate cuticular plates, the new genus is similar to Synhimantus Railliet, Henry & Sisoff, 1912, Dispharynx Railliet, Henry & Sisoff, 1912, Chordatortilis Machado de Mendon?a & Olivera de Rodrigues, 1965 and Parachordatortilis Mutafchiev, Santoro & Georgiev, 2010. Pelecanema sirry, a parasite of Pelecanus onocrotalus L. and P. crispus Bruch (Pelecaniformes, Pelecanidae) in Africa (Egypt and Senegal) and Europe (Ukraine and Bulgaria), is redescribed using light and scanning electron microscopy on the basis of specimens from P. crispus from Bulgaria. Pelecanema pelecani, a parasite of Pelecanus conspicillatus Temminck in Australia, is also redescribed using light microscopy on the basis of specimens from its type-host and type-locality. In contrast to a previous opinion recognising Pelecanema sirry and P. pelecani as synonyms, the two species are considered distinct and P. pelecani is validated.     

Pupation site choice of a North American lycaenid butterfly: the benefits of entering ant nests

Abstract.

• 1 Larvae of the North American lycaenid butterfly Hemiargus isola Reakirt tended by the ant Formica perpilosa Wheeler often enter nests of this ant species, and pupate in tunnels and chambers near the surface. Untended larvae and those tended by the ants Dorymyrmex Forel sp. (smithi complex), Forelius foetida (Buckley), and Myrmecocystus mimicus Wheeler pupate in crevices in the ground, under bark, and on leaves; but rarely inside ant nests.
• 2 The location and structure of F.perpilosa nests facilitates discovery by H.isola prepupae. At the southeast Arizona study site, F.perpilosa nests are located at the base of H.isola's host plant, whereas other species’nests are in open ground. Also, F.perpilosa nest openings are wide, whereas those of other species may be too narrow for prepupae to enter.
• 3 Prepupae associated with F.perpilosa spent 67% less time on the ground searching for pupation sites than prepupae associated with other ant species. Pupae in artificial chambers connected to F.perpilosa nests were 4–5 times less likely to disappear overnight, presumably due to predation, than those not connected to nests.
• 4 Formica perpilosa ants tend pupae inside nests. However, in the laboratory experiments tended pupae did not lose more weight prior to eclosion than untended ones, suggesting that chemicals or sounds produced by pupae as ant attractants are inexpensive, or are produced whether or not ants are present.
• 5 Newly-eclosed butterflies exited nests unmolested by ants in the field, but were attacked if confined with ants for several minutes after eclosion in the laboratory.

     

The expression of nr0b1, the earliest gene in zebrafish tooth development,is a marker for human tooth and ameloblastoma formation

Zebrafish teeth develop on pharyngeal jaws in the 5th branchial arch, but early tooth development is remarkably similar to mammals (Borday-Birraux et al., Evol Dev 8:130, 2006). Recently, eve1 has been shown to be associated with the primary tooth (4V¹) and early ameloblast development, the enamel organ precursor (Laurenti et al., Dev Dyn 230:727, 2004). dax1 is initially expressed in the 5th branchial arch in zebrafish at approximately 26 h postfertilization (hpf) and colocalizes with eve1 expression at ~48 hpf. Embryos injected with dax1 morpholino show downregulation of eve1 expression. Based on the zebrafish observations, we demonstrated novel DAX1 expression in normal human dental, benign ameloblastoma, and malignant ameloblastoma tissues. The association of NR0B1 and its protein product DAX1 with primary tooth development and ameloblastoma tumorigenesis is an association not previously described.     

The relationship between position on shore and shell ornamentation in two size-dependent morphotypes of Littorina striata,with an estimate of evaporative water loss in these morphotypes and in Melarhaphe neritoides

Shells of small (< 7 mm) Littorina striata are frequently nodulose, but shells of larger individuals are striate. Nodulose L. striata dominated the littoral fringe of a black basalt Azorean shore where daytime rock temperatures rose significantly higher than nearby shores of different rock composition or colour. There was no evidence of intraspecific size-partitioning on the latter shores, where the numbers of striate and nodulose L. striata were approximately equal between high eulittoral (low-shore) and high littoral fringe (high-shore) localities. The prevalence of small L. striata in the littoral fringe is opposite to that usually characteristic of the Littorinidae, where the largest individuals usually occupy the higher positions on the shore. It is hypothesized that small L. striata attain a resting posture better able to minimize heat absorption from the substratum than attained by larger individuals. Smaller individuals also take advantage of both posture and a nodulose shell surface to re-radiate absorbed incident radiant thermal energy more effectively to the atmosphere by convection. Thus, small, nodulose L. striata are especially well adapted to occupy geologically young basaltic rocks commonly found fringing islands of the mid-Atlantic. The rate of evaporative water loss was determined for Melarhaphe neritoides and striate and nodulose L. striata for approximately 11 days emersion. All three groups are exceptionally capable of controlling evaporative water loss. Total percent evaporative water loss by nodulose L. striata (17.9%) was significantly greater than that lost by either striate L. striata (14.1%) or M. neritoides (13.5%) but, among 15 species for which evaporative water loss has been determined by similar methodology, M. neritoides and striate L. striata are the most capable of conserving body water during 11 days of emersion.     

Observations of Portia Africana,an araneophagic jumping spider,living together and sharing prey

Abstract

Instances are documented of finding individuals of Portia africana in the field living aggregated in the webs of other spiders, in the nest complexes of other salticids, around solitary nests of other salticids, and around the nests of oecobiid spiders. Aggregation members included all active juvenile stages of P. africana, as well as adult males and females. More than one individual of P. africana sometimes fed on the same prey. Small juveniles of P. africana were more often than other stages found aggregated and more often observed feeding together. Small juveniles of P. africana surrounded the nests occupied by other salticid genera and nests occupied by oecobiid spiders. When the resident salticid or oecobiid attempted to leave or enter the nest, one of the P. africana juveniles lunged and captured it, after which other P. africana individuals sometimes joined to feed.