Paraponera Clavata Research Articles

Linear antimicrobial peptides from Ectatomma quadridens ant venom.

Venoms from three poneromorph ant species (Paraponera clavata, Ectatomma quadridens and Ectatomma tuberculatum) were investigated for the growth inhibition of Gram-positive and Gram-negative bacteria. It was shown that the venom of E. quadridens and its peptide fraction in particular possess marked antibacterial action. Three linear antimicrobial peptides sharing low similarity to the well-known ponericin peptides were isolated from this ant venom by means of size-exclusion and reversed-phase chromatography. The peptides showed antimicrobial activity at low micromolar concentrations. Their primary structure was established by direct Edman sequencing in combination with mass spectrometry. The most active peptide designated ponericin-Q42 was chemically synthesized. Its secondary structure was investigated in aqueous and membrane-mimicking environment, and the peptide was shown to be partially helical already in water, which is unusual for short linear peptides. Analysis of its activity on different bacterial strains, human erythrocytes and chronic myelogenous leukemia K562 cells revealed that the peptide shows broad spectrum cytolytic activity at micromolar and submicromolar concentrations. Ponericin-Q42 also possesses weak toxic activity on flesh fly larvae with LD50 of ∼105μg/g.

Tree ant family tree reveals swimming evolution

Life in the forest canopy is precarious: lose your footing and you could rule yourself out of the evolutionary arms race. Yet this hazard has not deterred many tropical ants from making their homes amongst the branches. In response to the risk of taking a tumble, many have developed the ability to glide to safety, although not all are lucky enough to land on another tree. Steve Yanoviak, from the University of Louisville, USA, explains that many plummet into water when the rivers below flood. However, when Yanoviak tried dropping tropical ants into water to find out what happened, he was amazed to see some species scuttle across the surface with ease. Intrigued, Yanoviak suggested that his Master's student, Dana Frederick, find out how widespread this swimming ability is and which swimming techniques, if any, the ants favour (p. 2163).Fortunately, both Yanoviak and Frederick had heads for heights and were unfazed dangling from climbing ropes in the forest canopy as they collected ants from the branches. ‘Some individual trees may have 20 or more ant species, so collecting workers of several species was not a major obstacle’, recalls Yanoviak, who was also adept at distinguishing between harmless species and ants that could give a painful sting.Having collected 35 species – ranging from minute Wasmannia rochai to gargantuan Paraponera clavata – the duo returned to the ground and tried gently dropping the ants from a bridge over a flooded region of the forest to see how they fared. ‘Over half (57%) of the tested species exhibited some swimming ability’, says Yanoviak, adding that the rest fell helplessly into the water. Of the swimmers, 10 proved to be elite athletes – with Gigantiops destructor notching up top speeds of over 16 cm s−1 – while the weakest 10 species eventually lumbered to safety after slow starts. The duo also analysed the ants' swimming prowess in terms of an ant family tree, discovering that the insects have evolved the ability to swim on four different occasions. And when the duo compared the ants' swimming abilities against their ability to glide, they found that the best gliders tended to be the weakest swimmers.Next the duo focused on the swimming techniques of three of the larger species (Odontomachus bauri, Pachychondyla foetida and P. villosa), filming the insects with a high-speed camera at 240 frames s−1 as they zipped across water in a shallow rectangular pan. ‘Recording high-speed videos of swimming ants in the lab was technically the most challenging part of the work’, recalls Yanoviak, adding that the ants would invariably stop performing when the filming conditions were perfect. However, after painstaking analysis, Frederick could see that the swimmers were alternately moving one and then the other tripod of legs; pulling the front two legs from each tripod through the water to propel themselves forward, while using the rear leg from each tripod to provide stability.Yanoviak and Frederick also wondered whether the immersed insects could locate and swim toward dark objects, such as trees, that they could climb to escape. Placing a 3.8 cm diameter black tube at one of the four compass bearings around a child's play pool, Frederick then dropped O. bauri ants into the water and waited to see which direction they aimed for. Amazingly, 87% of the ants successfully escaped the water by scaling the dark pipe, while only 23% of the ants successfully located a white pipe. Yanoviak admits that he was surprised by the strength of the ants' attraction to the dark object, known as scototaxis, and adds that he is now keen to understand how predatory fish respond to swimmers and non-swimmers that land in the water.

Distribution and dietary regulation of an associated facultative Rhizobiales-related bacterium in the omnivorous giant tropical ant, Paraponera clavata

We document a facultative Bartonella-like Rhizobiales bacterium in the giant tropical ant, Paraponera clavata. In a lowland tropical rainforest in Costa Rica, 59 colonies were assayed for the prevalence of the Bartonella-like bacterium (BLB), 14 of which were positive. We addressed three questions: First, how does the prevalence of BLB within colonies vary with environmental conditions? Second, how does diet affect the prevalence of BLB in P. clavata? Third, how does the distribution of BLB among colonies reflect ambient differences in food resources and foraging habits? A variety of environmental variables that may be predictive of the presence of BLB were measured, and diet manipulations were conducted to test whether the prevalence of BLB responded to supplemental carbohydrate or prey. The ambient frequency of BLB is much higher in young secondary forests, but is nearly absent from older secondary forests. The prevalence of BLB inside field colonies increased over the duration of a 2-week carbohydrate supplementation; however, water and prey supplementation did not alter the prevalence of BLB. The diets of the colonies located in young secondary forest, compared to other habitats, have a diet richer in carbohydrates and lower in prey. The abundance of carbohydrate, or the relative lack of N, in a colony's diet influences the occurrence of the BLB microbe in P. clavata. As experimental diet manipulations can affect the facultative presence of an N-cycling microbe, a consistent diet shift in diet may facilitate the emergence of tighter symbioses.

Especies de hormigas del suelo en el Parque Nacional Natural Gorgona, Pacífico Colombiano

Gorgona is one of the two insular areas of the Colombian tropical rain forest at the Pacific and is amongst the most diverse biogeographic regions of the world, the Choco. This study compiles information on ant species from published (1991) and unpublished (2006) studies and provides new records for ant species collected in 2010. Ants were sampled and information was obtained from 15 sites in Gorgona island (13.82km2), including the Gorgonilla atoll (0.49km2). Collecting methods included pitfall traps, tuna baits, mini-Winkler extraction of leaf litter, Malaise traps, entomological net and direct search. The soil and understory ant inventory resulted in 107 ant species and morphospecies, 46 genera in 12 subfamilies. Myrmicinae held the highest species richness (37 species), followed by Ponerinae (27) and Formicinae (12). The richest genera were Pachycondyla (15 species), Camponotus (nine) and Pheidole (eight), while 30 genera were represented by a single species. Twelve species were very common (both in distribution and time): Azteca sp., Atta cephalotes, Camponotus sericeiventris, Eciton vagans, Ectatomma goninion, Gnamptogenys annulata, Odontomachus bauri, Pachycondyla bugabensis, P. harpax, P. verenae, Paraponera clavata and Wasmannia auropunctata. Direct search was the most efficient method to collect diferent species and was responsible for 52% of the total species found. Compared to other Neotropical islands, Gorgona holds a suprisingly high number of ant species, none of them invasive. The invasive Monomorium floricola, which was collected 20 years ago, was not found in 2010. These evidences suggest that ecological mechanisms and natural recovery processes in the ecosystem have generated microhabitats allowing their coexistence. Rev. Biol. Trop. 62 (Suppl. 1): 265-276. Epub 2014 February 01.

To drink or grasp? How bullet ants (Paraponera clavata) differentiate between sugars and proteins in liquids

Flexibility in behavior can increase the likelihood that a forager may respond optimally in a fluctuating environment. Nevertheless, physiological or neuronal constraints may result in suboptimal responses to stimuli. We observed foraging workers of the giant tropical ant (also referred to as the "bullet ant"), Paraponera clavata, as they reacted to liquid solutions with varying concentrations of sugar and protein. We show that when protein/sucrose concentration is high, many bullet ants will often try to grasp at the droplet, rather than gather it by drinking. Because P. clavata actively hunt for prey, fixed action patterns and rapid responses to protein may be adaptively important, regardless of the medium in which it is presented. We conclude that, in P. clavata, food-handling decisions are made in response to the nutrient content of the food rather than the texture of the food. Further, we suggest that colonies that maintain a mixture of individuals with consistent fixed or flexible behavioral responses to food-handling decisions may be better adapted to fluctuating environmental conditions, and we propose future studies that could address this.

The Effects of the Conversion of a Primary to a Secondary Tropical Lowland Forest on Bullet ant (Paraponera clavata) Foraging Behavior in Costa Rica: A Possible Indicator of Ecosystem Condition

The use of bioindicators of habitat condition can help to better understand the effects of tropical forest degradation and the efficacy of strategies used in the restoration of these lands. The differences in feeding behavior of the ponerine ant Paraponera clavata may serve as such an indicator. The findings from the current study showed that P. clavata in an undisturbed primary forest returned to the nest with prey, nectar, and plant materials, while none of the ants within a 14 year old regenerating secondary forest returned with prey or nectar, few with plant materials, and most of the returns were unsuccessful in their foraging. This suggests a difference in P. clavata feeding behavior and/or food selection is occurring in the disturbed habitat; that P. clavata from the primary forest nest examined in the current study are feeding at a higher trophic level; and that the ants in the primary forest appeared to be more successful and efficient foragers than those in the secondary forest. Future studies should involve more comparisons of P. clavata foraging behavior in second- ary to primary forests to determine if the patterns described in this current study are consistent with disturbance in these tropical forests in order to evaluate the possibility of this use of P. clavata as a valuable tool for bioindicators of habitat damage.

Stem characteristics and ant body size in a Costa Rican rain forest

Abstract:Climbing plants provide efficient pathways for ants to access patchy arboreal resources. However, plant stems vary greatly in physical characteristics that are likely to influence ant locomotion. We collected, measured and identified ants foraging on 671 stems of climbing plants at the La Selva Biological Station, Costa Rica. We applied tuna baits to 70% of the observed stems to attract ants to a broad range of stem sizes. We used these data to examine relationships between relative stem roughness, growth form (herbaceous or woody), stem diameter and the body length of foraging ants representing 58 species. The size of the largest ants found on stems generally increased with stem size up to 3.2 mm diameter, whereas the size of the smallest ants present on stems did not vary with stem diameter. The largest ants in the forest (Paraponera clavata) used small stems (<2.7 mm diameter) only when attracted by baits. Average (± SE) ant body length was larger on woody (5.2 ± 0.32 mm) vs. herbaceous (3.3 ± 0.53 mm) stems, but did not differ between rough and smooth stems within these categories. Ant body-size distribution tended toward unimodality on smooth stems. We conclude that small stem diameter acts as a habitat filter based on ant body size, but only for the largest ants in the forest. The filter effect is reduced when ants are attracted to an artificially high quality resource.

Hormigas cazadoras en sistemas productivos del piedemonte amazónico colombiano: diversidad y especies indicadoras

Para conocer la abundancia, riqueza y composición de hormigas cazadoras y su variación en los sistemas productivos del departamento de Caquetá, se seleccionaron 27 fincas representativas de tres ventanas (agroforestal, silvopastoril y tradicional), en las cuales se identificaron hasta nueve clases de usos del suelo. Las proporciones dedicadas a pastos limpios, agroforestales y rastrojos viejos, fueron las que más contribuyeron a diferenciar las ventanas. Se muestrearon cinco puntos por finca mediante cuatro métodos para captura de hormigas (TSBF, lavado de suelo con formol, escrutinio de hojarasca y búsqueda directa). De un total de 280 individuos se determinaron nueve géneros y 35 especies de las subfamilias Ectatomminae, Paraponerinae y Ponerinae; el género más diverso fue Pachycondyla con 13 especies. La abundancia de hormigas se correlacionó directamente con la riqueza de especies y con el número de especies exclusivas. La riqueza fue mayor en la ventana agroforestal (24 especies), seguida de la silvopastoril (19) y de la tradicional (8). Cinco especies fueron comunes a las tres ventanas y siete especies (Ectatomma ruidum, Hypoponera sp.1 y sp.4, Odontomachus haematodus, O. brunneus y Pachycondyla constricta) marcaron las diferencias en composición. Odontomachus brunneus resultó indicadora para la ventana tradicional y Paraponera clavata para la ventana silvopastoril. La búsqueda directa fue el método más eficiente para muestrear hormigas cazadoras en el piedemonte amazónico.

A biochemical characterization of the major peptides from the Venom of the giant Neotropical hunting ant Dinoponera australis

Venom from the “false tocandira” Dinoponera australis, a giant Neotropical hunting ant, paralyzes small invertebrate prey and induces a myriad of systemic effects in large vertebrates. HPLC/DAD/MS analyses revealed that the venom has over 75 unique proteinaceous components with a large diversity of properties ranging in size, hydrophobicity, and overall abundance. The six most abundant peptides, demonstrative of this diversity and hereafter referred to as Dinoponeratoxins, were de novo sequenced by exact mass precursor ion selection and Edman degradation. The smallest peptide characterized, Da-1039, is hydrophilic and has similarities to vasoactive peptides like kinin and bombesin. The two largest and most abundant peptides, Da-3105 and Da-3177, have a 92.9% identity in a 28 residue overlap and share ∼50 of their sequence with ponericin G2 (an antimicrobial from another ponerine ant Pachycondyla goeldii). One peptide, Da-1585, is a hydrophilic cleavage product of an amphipathic peptide, Da-2501. The most hydrophobic peptide, Da-1837, is amidated (a PTM observed in one half of the major peptides) and shares homology with poneratoxin, a sodium channel modifier found in the bullet ant Paraponera clavata. This study is the first examination of potential pharmacophores from venom of the genus Dinoponera (Order: Hymenoptera).

Lifespan in male ants linked to mating syndrome

Male ants have long been thought to leave the nest, swarm, mate and die in quick succession (male aggregation syndrome). However, the ancestors of the ants likely used female calling, where females advertise with pheromones for longer lived and presumably free living males. In this study, male lifespan was compared in four species from a Panama rain forest. Males of two species with aggregation syndrome (Atta colombica and Azteca sp.) lived only days after collection at a light trap, and their lifespan failed to increase when supplied sugar water ad libitum. In contrast, two species with female calling syndrome (Ectatomma ruidum and Paraponera clavata) lived up to 116 days when fed. These results link male lifespan to mating systems, and provide a framework to examine variation in how ant colonies invest in males.

A Predictive Distribution Map for the Giant Tropical Ant,Paraponera clavata

Paraponera clavata (Fabricius 1775) (Formicidae: Paraponerinae) is a widely distributed Neotropical ant whose large size has attracted the attention of numerous collectors. Working from museum specimens, a georeferenced database of collection localities was developed. This database then served as the source for computer generated predictive distribution maps. Annual rainfall was the most important variable chosen by the computer model to predict the distribution of P. clavata, both on the scale of the neotropics and at a finer scale at the northern end its distribution in Costa Rica and Nicaragua. When the model was forced to use vegetation as the first predictive variable, the Neotropical model used temperature and rainfall variance as additional variables, while the Mesoamerican model used both climatic and soils variables. Overall, the modeling suggests that P. clavata is more sensitive to abiotic factors (rainfall, temperature, soils) than to biotic factors (vegetation type) in its distribution, although this conclusion comes with the caveat that the vegetation types used in the model are quite generalized. Predictive distribution mapping holds great promise for generating more precise representations of insect distributions, thereby allowing better tests of the extent of distribution overlaps and other community relationships.

Identification and structural analysis of a glycophospholipid component from the venom of ant Paraponera clavata

The venom of South American ant Paraponera clavata and its low-molecular-mass fraction were shown to possess insectotoxic and pore-forming activities. A number of glycophospholipid components were isolated from this ant venom by means of gel filtration and reversed-phase chromatography. Some of the compounds cause conductivity fluctuations in lipid bilayer membranes within the ranges 3-25 pS and 200-400 pS at concentrations of 10(-6) to 10(-7) M. N-Acetylglucosamine, a fatty acid, and phosphoric acid residues were found in their structures. A full structure, 3-myristoyl-2-acetamido-2-deoxy-alpha-D-glucopyranosyl phosphate, was elucidated for one of the compounds by the use of 1H, 13C, and 31P NMR spectroscopy and mass spectrometry.

The effect of water on the ground nesting habits of the giant tropical ant, Paraponera clavata

The large predatory ant, Paraponera clavata, exerts measurable top-down effects in wet and moist Neotropical forests, and therefore its distribution has potential ecological implications. To determine how water affects the presence of this important predator, the ground nesting ecology of P. clavata was examined with respect to various habitat characteristics. Four hectares of disturbed Costa Rican lowland rain forest were surveyed for ant colonies to determine nest distribution patterns in wet and dry habitat; significantly more colonies were found in dry habitat. Seventeen of 19 nests built on slopes of > 5° inclination were positioned on the downward side of the tree, possibly using the trunk as a shield against runoff during rain showers. Moisture and pH inside nests were significantly different from adjacent soil. These results suggest that water influences the ground nesting habits of P. clavata, thus ecological differences between comparatively wet and dry portions of tropical forests may arise from the relative abundance of this ant species.

The effect of water on the ground nesting habits of the giant tropical ant, Paraponera clavata

The large predatory ant, Paraponera clavata, exerts measurable top-down effects in wet and moist Neotropical forests, and therefore its distribution has potential ecological implications. To determine how water affects the presence of this important predator, the ground nesting ecology of P. clavata was examined with respect to various habitat characteristics. Four hectares of disturbed Costa Rican lowland rain forest were surveyed for ant colonies to determine nest distribution patterns in wet and dry habitat; significantly more colonies were found in dry habitat. Seventeen of 19 nests built on slopes of > 5 degrees inclination were positioned on the downward side of the tree, possibly using the trunk as a shield against runoff during rain showers. Moisture and pH inside nests were significantly different from adjacent soil. These results suggest that water influences the ground nesting habits of P. clavata, thus ecological differences between comparatively wet and dry portions of tropical forests may arise from the relative abundance of this ant species.

Poneratoxin, a neurotoxin from ant venom. Structure and expression in insect cells and construction of a bio-insecticide.

Poneratoxin is a small neuropeptide found in the venom of the ant Paraponera clavata. It is stored in the venom reservoir as an inactive 25-residue peptide. Here we describe both chemically synthesized poneratoxin and poneratoxin obtained by expression in insect cells. When expressed in insect cells, poneratoxin was observed attached to cell membranes. Both synthetic and recombinant ponerotoxins were soluble below pH 4.5. The structure of synthetic poneratoxin was characterized by circular dichroism and solved by nuclear magnetic resonance. In an environment imitating a lipid bilayer, at pH within the range of insect hemolymph, synthetic poneratoxin has a V shape, with two alpha-helices connected by a beta-turn. Insect larvae were paralyzed by injection of either of the purified toxins, with the recombinant one acting faster. The recombinant toxin-producing baculovirus reduced the average survival time of the insect host by 25 h compared with unmodified virus. Mass spectrometry analysis showed that the recombinant toxin has an N-terminal 21-residue extension, possibly improving its stability and/or stabilizing the membrane-bound state. The potential use of poneratoxin for the construction of biological insecticide is discussed.

Placing an Omnivore in a Complex Food Web: Dietary Contributions to Adult Biomass of an Ant1

ABSTRACT Workers of Paraponera clavata, a common Neotropical ant, collect both nectar and insect prey. Previous reports show that nectar accounts for up to 90 percent of the ants' food loads, while calculations suggest that nectar contributes only 10 percent of colonies' energy supply. We assessed the trophic source of carbon and nitrogen in adult workers using stable isotope analysis. Carbon in adult workers was largely derived from plant sources. Worker nitrogen isotopic ratios varied significantly among colonies and were enriched compared to prey. Prey nitrogen isotope ratios suggest considerable intercolonial variation in diet, with some colonies collecting prey from lower trophic levels than other colonies. The importance of nectar as a source of metabolic carbon in adult worker biomass, coupled with the high frequency of nectar collection, supports the conclusion that omnivory is a key to supporting this species' biomass in Neotropical wet forests.

A bioassay for insect deterrent compounds found in plant and animal tissues.

A general field bioassay for detecting biologically active compounds in plants and insects has been developed and tested for efficacy and sensitivity. Methanolic extracts, in sucrose solution, of 20 plant and six caterpillar species were offered to the ponerine ant Paraponera clavata and the feeding preferences observed. The bioassay resulted in the detection of nine plant and three caterpillar species with ant-deterrent extracts, and 11 plant and three caterpillar species with neutral or attractant extracts. All of the plants showing ant-deterrent characteristics which had been chemically investigated in our laboratory, or for which chemical literature was available, contained secondary metabolites of known deterrence. Both naturally occurring and artificial differences in chemical concentrations could be detected using the bioassay. The method provides a means of screening plants and insects for compounds that are insect anti-feedants or that can modify insect behaviour.

Synergistic effects of three Piper amides on generalist and specialist herbivores.

The tropical rainforest shrub Piper cenocladum, which is normally defended against herbivores by a mutualistic ant, contains three amides that have various defensive functions. While the ants are effective primarily against specialist herbivores, we hypothesized that these secondary compounds would be effective against a wider range of insects, thus providing a broad array of defenses against herbivores. We also tested whether a mixture of amides would be more effective against herbivores than individual amides. Diets spiked with amides were offered to five herbivores: a naïve generalist caterpillar (Spodoptera frugiperda), two caterpillar species that are monophagous on P. cenocladum (Eois spp.), leaf-cutting ants (Atta cephalotes), and an omnivorous ant (Paraponera clavata). Amides had negative effects on all insects, whether they were naïve, experienced, generalized, or specialized feeders. For Spodoptera, amide mixtures caused decreased pupal weights and survivorship and increased development times. Eois pupal weights, larval mass gain, and development times were affected by additions of individual amides, but increased parasitism and lower survivorship were caused only by the amide mixture. Amide mixtures also deterred feeding by the two ant species, and crude plant extracts were strongly deterrent to P. clavata. The mixture of all three amides had the most dramatic deterrent and toxic effects across experiments, with the effects usually surpassing expected additive responses, indicating that these compounds can act synergistically against a wide array of herbivores.

A quantification of predation rates, indirect positive effects on plants, and foraging variation of the giant tropical ant, Paraponera clavata

While a clear consensus is emerging that predators can play a major role in shaping terrestrial communities, basic natural history observations and simple quantifications of predation rates in complex terrestrial systems are lacking. The potential indirect effect of a large predatory ant, Paraponera clavata Fabricius (Formicidae: Ponerinae), on herbivores was determined on rainforest trees at La Selva Biological Station in Costa Rica and Barro Colorado Island in Panama. Prey and other food brought back to nests by 75 colonies of P. clavata were quantified, taking into account temporal, seasonal, and microhabitat variation for both foraging activity and composition of foraging booty. The dispersion and density of ant colonies and combined density with the mean amounts of prey retrieval were used to calculate rates of predation per hectare in the two forests. In addition, herbivory was measured on trees containing P. clavata and on trees where the ants were not foraging. Colonies at La Selva brought back significantly more nectar plus prey than those at Barro Colorado Island, but foraging patterns were similar in the two forests. At both forests, the ants were more active at night, and there was no significant seasonal or colonial variation in consumption of nectar, composition of foraging booty, and overall activity of the colonies. At La Selva, trees containing P. clavata colonies had the same levels of folivory as nearest neighbor trees without P. clavata but had significantly lower folivory than randomly selected trees. Predation by this ant was high in both forests, despite its omnivorous diet. This insect predator is part of potentially important top-down controls in these wet and moist forests.

Allometry in the giant tropical ant, Paraponera clavata

Workers of the ponerine ant, Paraponera clavata, grow allometrically, with the head disproportionately larger in larger workers. The anterior (clypeus)-posterior (occiput) dimension of the head capsule is allometric with the lateral (interocular) dimension, so that larger workers have elongate heads. The degree of head capsule allometry varies among colonies; this could result either from differences in colony maturity or from variation in developmental patterns among colonies. These data resolve a previously controversial issue concerning caste in Paraponera clavata.