Ant Predation Research Articles

Foraging by predatory ants: A review.

In this review, we show that predatory ants have a wide range of foraging behavior, something expected given their phylogenetic distance and the great variation in their colony size, life histories, and nesting habitats as well as prey diversity. Most ants are central-place foragers that detect prey using vision and olfaction. Ground-dwelling species can forage solitarily, the ancestral form, but generally recruit nestmates to retrieve large prey or a group of prey. Typically, ants are omnivorous, but some species are strict predators preying on detritivorous invertebrates or arthropod eggs, while those specialized on termites or other ants often have scouts that localize their target and then trigger a raid. They can use compounds that ease this task, including chemical insignificance, mimicry, and venoms triggering submissive behavior. Army ants include 8 Dorylinae and some species from other subfamilies, all having wingless queens and forming raids. Dorylinae from the Old World migrate irregularly to new nesting sites. The foraging of most New World species that prey on the brood of other ants is regulated by their biological cycle that alternates between a "nomadic phase" when the colony relocates between different places and a "stationary phase" when the colony stays in a bivouac constituting a central place. Among arboreal ants, dominant species forage in groups, detecting prey visually, but can use vibrations, particularly when associated with myrmecophytes. Some species of the genera Allomerus and Azteca use fungi to build a gallery-shaped trap with small holes under which they hide to ambush prey.

An extensive review of mutualistic and similar ecological associations involving tarantulas (Araneae: Theraphosidae), with a new hypothesis on the evolution of their hirsuteness

ABSTRACT Mutualistic and similar ecological associations between tarantulas (Mygalomorphae: Theraphosidae) and other animals are reviewed. Such associations are found to occur in at least nine theraphosid subfamilies. We present 63 new cases of theraphosid–anuran associations from 10 countries, documenting these interactions for the first time in Brazil, Chile, the Dominican Republic, and the Philippines. These findings are the first documentation of such associations for 13 theraphosid and 20 anuran taxa. Additionally, we report, for the first time, associations potentially of mutualistic nature between tarantulas and snakes, whip spiders, and harvestmen. Furthermore, we provide new reports of associations with ants and termites. While some of these interactions appear to be merely tolerated cohabitations, those involving anurans and ants seem to be more prevalent and complex, clearly offering benefits for both organisms. Additionally, based on multiple observations and field experiments, we propose a new hypothesis regarding the evolution of hirsuteness in theraphosids as a defensive strategy against predatory ants. This hypothesis supports previous findings that suggest a similar function for urticating setae incorporated into egg sacs and moulting mats. We further document a unique escape strategy against ants in New World arboreal theraphosids. Finally, the possibility of a chemical defence mechanism through specialised epidermal glands in theraphosids is briefly discussed.

Hunting habits die hard: Conserved prey preferences in army ants across two distant neotropical rainforests

AbstractArmy ants are widely recognized as keystone species in neotropical rainforests due to their role as important arthropod predators. Their large‐scale raids involve thousands of workers scouring the forest floor in pursuit of prey, primarily capturing other invertebrates. Up to 20 species of army ants coexist in a rainforest, and dietary niche differentiation has been proposed as a mechanism to alleviate competition among them. Based on only a handful of study sites, however, our understanding of the precise dietary preferences and the extent of niche differentiation remains notably limited. In this study, we aimed to expand our knowledge of army ant communities by resolving an Ecuadorian predation network consisting of 244 prey species and 13 army ant species representing the five known neotropical army ant genera: Cheliomyrmex, Eciton, Labidus, Neivamyrmex, and Nomamyrmex. We collected 2156 prey items from 180 army ant raids/emigrations, and of these, we identified 1945 prey items to the family level, 1313 to the genus level, and 664 to the species level based on morphological identifications and DNA barcodes. Prey consisted primarily of other ants (1843 prey items; 153 ant species), to the largest part ant brood (N = 1726). Hence, most army ant species chiefly plundered the nests of other ants, while the three swarm raiding species, that is, Lab. praedator, Lab. spininodis, and Ec. burchellii, exhibited a relatively high proportion of non‐ant invertebrate prey in their diet. The predation network showed a high degree of specialization (H2′ = 0.65), characterized by little dietary niche overlap among sympatric species. We compared the Ecuadorian network with one previously studied in Costa Rica and found that, despite the large geographic distance, prey preferences remained remarkably similar. We discovered species‐specific preferences for captured ant genera and species, despite some species turnover in both army ants and prey. Additionally, army ants also exhibited consistent spatiotemporal raiding preferences across study sites. In conclusion, predation preferences within army ant communities exhibited consistency in multiple niche dimensions across two distant neotropical rainforests, suggesting a notable level of predictability within army ant predation networks.

Ecosystem functions of ants and dung beetles in agriculture‐dominated Amazonian riparian forests

Abstract Land‐use changes and habitat fragmentation can alter biodiversity and associated ecosystem functions. We investigated whether cropland expansion in south‐east Amazonia decreases ecosystem functions performed by ants and dung beetles by altering their communities. We sampled both groups in two forest types, in south‐eastern Amazonia: undisturbed riparian forests and riparian forests surrounded by croplands. We sampled ants and dung beetles with epigaeic pitfall traps, and experimentally assessed seed removal and predation by ants, and faeces and seed removal by dung beetles. Although ant and dung beetle abundance and richness did not differ across riparian forests, species composition of both groups did. Ants found seeds faster in undisturbed riparian forests, but the proportion of seed removal did not differ between forests. The abundance of predatory ants and the predation of termites by ants did not differ between forests. Seed and dung removal by dung beetles did not differ across riparian forests. Despite the observed differences in dung beetle composition, we did not find the effects on ecosystem functions probably due a functional redundancy of species. The quality of ecosystem functions provided by ants is lower in riparian forests surrounded by croplands, while changes in dung beetle diversity did not impact their ecosystem functions, with potential effects on the natural recovery of these disturbed riparian forests.

Investigation the Potential of Myopopone castanea Smith (Hymenoptera: Formicidae) as Bio-Agent of Oryctes rhinoceros (Coleoptera: Scarabaediae) in Oil Palm Plantations

The Myopopone castanea Smith (Hymenoptera: Formicidae) is a predator of Oryctes rhinoceros Linn larvae, the main pest on oil palm plantations. These predatory ants have potential as biological agents because they have similar niches to their prey. This research aimed to explore the presence and potential of M. castanea as bio-agents in oil palm plantations and obtain knowledge about the abiotic environment of Myopopone castanea ant nests. The research was conducted in oil palm plantations owned by PTPN 4 Adolina, PTPN 2 Pagar Merbau, and smallholder oil palm plantations in Binjai, North Sumatra Province. Sampling was conducted using the purposive sampling method and as many as 10 sample points in each plantation. The results showed that the average temperature and humidity in the ant nests were 29.4 °C and 70.5%, respectively. The number of individual ants in a colony varied greatly in number and developmental stages. The predation potential of Myopopone castanea ants in the field reached 50.3% for five days of exposure in smallholder plantations and 46,9% in Adolina Plantation. This research could be the opportunity to use Myopopone castanea ants as a biological control for larvae Oryctes rhinoceros in oil palm plantations.

The abundance of ants (Hymenoptera: Formicidae) and their ecological roles as predators in Arabica coffee plantations with different densities of shade trees

Shade-grown coffee, incorporated in an agroforestry system, is a common practice of coffee plantations in Aceh Tengah Regency, Aceh Province, Indonesia. Coffee is grown under the shade of a canopy of surrounding trees. Shade trees reduce excessive light and provide a home for various predatory animals, including predatory ants. Some growers plant a dense population of shade trees, while others plant less shade trees. A study to investigate the diversity of ants and their abundance in different densities of shade trees has been conducted from April until August 2023. Ants were sampled from coffee trees (arboreal ants) in two coffee plantations with dense populations of shade trees and two plantations with sparse shade trees. We found 13 ant species in both categories of plantations (combined). All ant species were found in sparsely shaded coffee plantations, and only five were recorded from densely shaded plantations. However, the abundance of ants was much higher in densely shaded plantations than in sparsely shaded plantations. The ant genera Technomyrmex and Componatus were the dominant ants found in sparsely shaded plantations, while the dominant ants in densely shaded plantations were the genera Componatus and Crematogaster. These ants are known as general predators and potentially are predators of coffee berry borer (CBB), a significant pest in the area. This research has shown how different densities of shade trees in coffee plantations affected the ant fauna, which could be used as a basis for ant conservation to increase their ecosystem service as predators.

Ants (Formicidae) and their predatory conduct in relation to biological control in District Wardha, Maharashtra, India

Ants are scavengers and predators in several agricultural crop fields. There is a growing interest in ant predatory behaviour in agricultural fields, although the practical applications are limited. The Vidarbha region includes District Wardha, which has amazing agricultural land. In the present study, the predatory behaviour of ants on pest of crop field in district Wardha has been studied. Soybean, cotton, maize, gram, wheat and pigeon pea are principal crops of the region. There are number of insect pest (Lepidoptera) which infest to crop. The ants positively impact on agricultural system as biological control agents. The predatory ants Tapinoma, Pheidole, Crematogaster and Componotus control the pest population in crop field. The method of controlling pests by employing naturally occurring ant species to reject inputof chemical pesticide must be continued to save environment.

Intercropped Flemingia macrophylla successfully traps tea aphid (Toxoptera aurantia) and alters associated networks to enhance tea quality.

The tea aphid, Toxoptera aurantia is a destructive pest causing severe damage to the quality and yield of tea, Camellia sinensis. Relying on chemical insecticides to control this pest causes adverse ecological and economic consequences. Trap plants are an eco-friendly alternative strategy to mitigate pest damage on focal plants by attracting target insects and natural enemies. Yet, the utilization of trap plants in tea plantations remains limited. Besides, the effects of the trap plant on the tea aphid-ant-predator community and tea quality and yield are unknown. Intercropped Flemingia macrophylla successfully trapped tea aphids and enhanced the complexity of aphid-ant-predator networks over three consecutive years compared to monoculture management. Moreover, F. macrophylla significantly increased the abundance of natural predators by 3100% and species richness by 57%. The increasing predators suppressed the aphid population and hampered its spillover to neighbouring tea plants. Consequently, F. macrophylla improved tea quality by an 8% increase in soluble sugar and a 26% reduction in polyphenols to amino acids ratio. The study illustrated that F. macrophylla is a suitable trap crop for tea aphid control in tea plantations. This legume increases species nodes and strengthens multiple connections in aphid-associated communities through its cascade effects, improving tea quality. These findings shed light on the potential application of trap plants in tea plantations as an efficient integrated pest management (IPM) strategy. © 2023 Society of Chemical Industry.

The effects of early-life and intergenerational stress on the brain.

Stress experienced during ontogeny can have profound effects on the adult phenotype. However, stress can also be experienced intergenerationally, where an offspring's phenotype can be moulded by stress experienced by the parents. Although early-life and intergenerational stress can alter anatomy, physiology, and behaviour, nothing is known about how these stress contexts interact to affect the neural phenotype. Here, we examined how early-life and intergenerational stress affect the brain in eastern fence lizards (Sceloporus undulatus). Some lizard populations co-occur with predatory fire ants, and stress from fire ant attacks exerts intergenerational physiological and behavioural changes in lizards. However, it is unclear if intergenerational stress, or the interaction between intergenerational and early-life stress, modulates the brain. To test this, we captured gravid females from fire ant invaded and uninvaded populations, and subjected offspring to three early-life stress treatments: (1) fire ant attack, (2) corticosterone, or (3) a control. Corticosterone and fire ant attack decreased some aspects of the neural phenotype while population of origin and the interaction of early-life stress and population had no effects on the brain. These results suggest that early-life stressors may better predict adult brain variation than intergenerational stress in this species.

One ant's trash is another ant's treasure: Army ant middens provide resources for diverse ant assemblages

AbstractThe army ant Eciton burchellii boasts more animal associates than any other animal species yet described, but the relationship between army ants and other ant species has only been studied in the context of predation. The waste deposits (middens) of army ant colonies are nitrogen‐rich, a potentially high‐value nutrient source for leaflitter arthropods. We explored this bottom‐up role of army ant middens in the context of tropical ant communities. Our three main questions were the followings: (1) Which ant species forage on army‐ant middens? (2) How does the bi‐phasic life cycle of army ant colonies (affecting midden size, persistence, and abundance) affect which and how many ant species a midden boasts? (3) How do the ants that forage on army ant middens differ across elevations? Across 39 bivouacs, we found 36 species of ants foraging on army ant middens. These included highly predatory ants, nitrogen‐limited arboreal ants, and fungus‐farming ants. Per‐midden richness was significantly lower for the usually smaller middens deposited during the nomadic phase and was higher for the typically larger middens deposited during the statary phase. Per‐midden richness was not significantly different across elevations, but there was far greater species turnover across elevations than across phases within the same elevational site. Our results suggest that army ant middens are an important resource for a wide variety of tropical ants, informing a better understanding of the complex network of associations revolving around this keystone species.Abstract in Spanish is available with online material

Trait-Based Paleontological Niche Prediction Recovers Extinct Ecological Breadth of the Earliest Specialized Ant Predators.

AbstractPaleoecological estimation is fundamental to the reconstruction of evolutionary and environmental histories. The ant fossil record preserves a range of species in three-dimensional fidelity and chronicles faunal turnover across the Cretaceous and Cenozoic; taxonomically rich and ecologically diverse, ants are an exemplar system to test new methods of paleoecological estimation in evaluating hypotheses. We apply a broad extant ecomorphological dataset to evaluate random forest machine learning classification in predicting the total ecological breadth of extinct and enigmatic hell ants. In contrast to previous hypotheses of extinction-prone arboreality, we find that hell ants were primarily leaf litter or ground-nesting and foraging predators, and by comparing ecospace occupations of hell ants and their extant analogs, we recover a signature of ecomorphological turnover across temporally and phylogenetically distinct lineages on opposing sides of the Cretaceous-Paleogene boundary. This paleoecological predictive framework is applicable across lineages and may provide new avenues for testing hypotheses over deep time.

Context-Dependent Ant-Pollinator Mutualism Impacts Fruit Set in a Hummingbird-Pollinated Plant

Context-dependence in mutualisms is a fundamental aspect of ecological interactions. Within plant-ant mutualisms, particularly in terms of biotic protection and pollination, research has predominantly focused on elucidating the benefits while largely overlooking potential costs. This notable gap underscores the need for investigations into the drawbacks and trade-offs associated with such mutualistic relationships. Here, we evaluated the role of pericarpial nectaries (PNs) in shaping the dynamics of ant-pollinator mutualisms. Specifically, we investigated whether ants visiting the PN of Palicourea rigida (Rubiaceae) could deter hummingbirds and disrupt pollination, ultimately influencing fruit production. Our research involved manipulative experiments and observation of ant-pollinator interactions on P. rigida plants in the Brazilian savannah. We found that visiting ants can deter hummingbirds and/or disrupt pollination in P. rigida, directly influencing fruit set. However, these results are species-specific. The presence of very aggressive, large predatory ants, such as E. tuberculatum, had a negative impact on hummingbird behavior, whereas aggressive mid-sized ants, such as C. crassus, showed no effects. Our study illuminates the multifaceted aspects of ant-plant mutualisms and underscores the importance of evaluating costs and unexpected outcomes within these ecological relationships.

Obligate Ant-Associated Macaranga bancana is Better Protected from Herbivory Than Facultative Ant-Associated Macaranga tanarius

Protective mutualism between ant and Macaranga plants are complex between-species interactions found only in the tropical environment. In such interactions, plants provide housing structures (in the form of domatia) and food (in the form of food bodies) to their ant symbionts. In return, the ants protect their Macaranga plant hosts against herbivore attacks. Macaranga ant protective mutualism is manifested in a wide range of interactions, from facultative to obligate. In facultative interactions, Macaranga plants attract predatory ants to the plant via food rewards. In return, foraging ants may opportunistically provide protection from insect herbivores. In obligate interactions, plants provide shelter and food rewards to permanent ant partners. We hypothesize that in obligate Macaranga, the host is better protected because of the permanent presence of its resident ant partners, whereas in facultative Macaranga, the defense against insect herbivores may be less efficient depending on the attractiveness of the food rewards and the aggressiveness of the ant species in the plant’s vicinity. In this study, we compare herbivory damage and phytophagous insect herbivore types between a facultative ant-plant M. tanarius and an obligate anti-plant M. bancana. This study further highlights that co-evolved ant partners are more efficient in defending their host plants against phytophagous insect herbivores than facultative ant-plant interactions.

Simulated biomechanical performance of morphologically disparate ant mandibles under bite loading

Insects evolved various modifications to their mouthparts, allowing for a broad exploration of feeding modes. In ants, workers perform non-reproductive tasks like excavation, food processing, and juvenile care, relying heavily on their mandibles. Given the importance of biting for ant workers and the significant mandible morphological diversity across species, it is essential to understand how mandible shape influences its mechanical responses to bite loading. We employed Finite Element Analysis to simulate biting scenarios on mandible volumetric models from 25 ant species classified in different feeding habits. We hypothesize that mandibles of predatory ants, especially trap-jaw ants, would perform better than mandibles of omnivorous species due to their necessity to subdue living prey. We defined simulations to allow only variation in mandible morphology between specimens. Our results demonstrated interspecific differences in mandible mechanical responses to biting loading. However, we found no evident differences in biting performance between the predatory and the remaining ants, and trap-jaw mandibles did not show lower stress levels than other mandibles under bite loading. These results suggest that ant feeding habit is not a robust predictor of mandible biting performance, a possible consequence of mandibles being employed as versatile tools to perform several tasks.

Critical stage and key natural mortality factors of Hypothenemus hampei in commercial coffee plantations

AbstractThe coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), is one of the most important coffee pests, and is present in almost all countries producing this crop, causing annual losses of US$350 million. Natural factors regulate H. hampei populations in coffee crops. Ecological life table analysis is a robust tool that allows the estimation of the mortality caused by these factors. Therefore, the main objective of this study was to determine the critical stage and the key mortality factors affecting H. hampei in the field. Data for constructing life tables were collected over 2 years in six coffee plantations in the regions of Paula Cândido and Viçosa, Minas Gerais State, Brazil. The average mortality of H. hampei was 75.34% ± 5.85%. The mortality at each developmental stage was 24.32% ± 2.83% (eggs), 7.29% ± 1.01% (first instar), 11.58% ± 1.46% (second instar), 9.68% ± 1.10% (third instar), 7.45% ± 1.01% (pupa), and 15.02% ± 1.29% (adult; n = 124). The mortality factors observed and quantified in this study were parasitism by Prorops nasuta (Hymenoptera: Bethylidae), predation by ants (Crematogaster spp., Pheidole spp. and Solenopsis spp.), physiological disorders and fungal infection by Beauveria bassiana and Metarhizium anisopliae. The critical mortality stage of H. hampei was the adult stage. The key factors for mortality of H. hampei adults were predatory ants, followed by B. bassiana and malformations (these insects had deformities in the head, wings, legs, or abdomen). This information is essential to conserve the activities of natural enemies and, thus maintain H. hampei natural mortality factors in coffee plantations, reducing damage to the crops and the need for excessive insecticide interventions.

Interactions between egg parasitoids and predatory ants for the biocontrol of the invasive brown marmorated stink bug Halyomorpha halys

AbstractThe brown marmorated stink bug Halyomorpha halys is an Asian species that has become a major agricultural pest in North America and Europe. Ants from the genus Crematogaster are predators of H. halys nymphs in Asia, as well as in the Mediterranean, where known native predators are still few. At the same time, ants usually do not harm H. halys eggs, which are the target of the main biological control agents, the scelionid parasitoids of the genus Trissolcus. However, ants, as generalist predators and territorial organisms, may kill or displace a variety of other insects, potentially interfering with parasitoids and biological control programmes. We conducted laboratory experiments to investigate the interactions between the Mediterranean ant Crematogaster scutellaris and the parasitoids T. japonicus and T. mitsukurii, evaluating the possibility that the ants could damage the parasitized eggs, attack the parasitoids during emergence or interfere with the egg‐laying behaviour of female parasitoids. Our results demonstrate that C. scutellaris is not able to damage parasitized eggs and is not aggressive towards adult parasitoids at any stage. The presence of ants can slow down the parasitization rate in T. mitsukurii females in the smallest laboratory setups; however, this has not been observed in a more natural setting. We suggest that ants may play a complementary role together with egg‐parasitoids in the control of H. halys without interfering with each other.

Predatory ants invading sea turtle nests on the East Coast of Peninsular Malaysia

Predatory ants invading sea turtle nests on the East Coast of Peninsular Malaysia

Mathematical Model for the Biological Control of the Coffee Berry Borer Hypothenemus hampei through Ant Predation.

Coffee is a relevant agricultural product in the global economy, with the amount and quality of the bean being seriously affected by the coffee berry borer Hypothenemus hampei (Ferrari), CBB, its principal pest. One of the ways to deal with this beetle is through biological control agents, like ants (Hymenoptera: Formicidae), some of which are characterized by naturally inhabiting coffee plantations and feeding on CBB in all their life stages. Our paper considers a predator-prey interaction between these two insects through a novel mathematical model based on ordinary differential equations, where the state variables correspond to adult CBBs, immature CBBs, and ants from one species, without specifying whether preying on the CBB is among their feeding habits, in both adult and immature stages. Through this new mathematical model, we could qualitatively predict the different dynamics present in the system as some meaningful parameters were varied, filling the existing gap in the literature and envisioning ways to manage pests. Mathematically, the system's equilibrium points were determined, and its stability was studied through qualitative theory. Bifurcation theory and numerical simulations were applied to illustrate the stability of the results, which were interpreted as conditions of the coexistence of the species, as well as conditions for eradicating the pest, at least theoretically, through biocontrol action in combination with other actions focused on eliminating only adult CBBs.

Comparing Insect Predation by Birds and Insects in an Apple Orchard and Neighboring Unmanaged Habitat: Implications for Ecosystem Services.

Preserving ecosystem services, such as natural enemies that can provide pest control, can positively impact crops without compromising agricultural yield. Even though controlling pests by natural enemies has been suggested to reduce pests in agriculture, growers continue using conventional pesticides that kill beneficial predators. Here we studied whether the predation of avian and insect-beneficial predators varies in an apple orchard with conventional insecticide use compared to a bordering tree stand without insecticides. We studied the predation rates of mealworm pupae as a proxy to coddling moth pupae at 42 stations in both an apple orchard and a Eucalyptus stand at three distances (0 m, 50 m, and 100 m) from the border. Half of the stations were netted to prevent bird predation but were accessible to insects. The other half were non-netted and accessible to birds. We conducted six trials, each lasting two weeks, during which we recorded the predation of 504 stations with 5040 pupae. To validate which species predated the pupae, we added video cameras that took RGB videos during the day and IR videos at night in 45 stations and found that in net-free stations, birds preyed in 94.1% of stations in the orchard and 81.8% in the Eucalyptus stand. However, ants predated 70% of the pupae in stations with nets in the orchards and 100% in stations in the Eucalyptus strands. In addition, we found a significant rise in predation by birds as the distance into the orchard increased. Conversely, insect predation declined within the orchard but escalated in the adjacent unmanaged area. These findings suggest that the orchard's environment negatively affects beneficial insect activity, specifically predatory ants. This study demonstrates that birds can play an essential role in predating insect pests inside the orchard. In addition, we believe that the decreased predation of ants within the orchard was due to intense insecticide use.

Within-field crop diversity and landscape complexity decrease the abundance of fall armyworm larvae in maize cropping systems

The composition and spatial arrangement of multiple crop and non-crop habitats at a field and landscape levels have the potential to modify the abundance and structure of arthropod communities. In particular, semi-natural habitats can provide important life support functions to a range of natural enemies of agricultural pests. How such traits might affect generalist predators has poorly been considered in complex landscapes dominated by intercropping and trees within a mosaic of small-scale agricultural plots in Africa. The objective of the present study was to test the hypothesis that crop diversity and landscape complexity in maize cropping systems decrease the abundance of crop pests through natural regulation by generalist predators. For this purpose, we monitored the fall armyworm abundance and predation of sentinel larvae by predatory ants across a set of maize fields with contrasted within-field crop diversity and abundance of semi-natural vegetation including trees and shrubs in their surrounding landscape. A negative effect of crop diversity and landscape complexity on FAW abundance, and a species-specific effect on ant abundance, were observed. However, no significant effect of ant abundance or predation on FAW abundance was observed, suggesting that habitat complexity by itself or other natural enemy communities such as parasitoids could play a complementary role to explain FAW abundance in maize crops.