Ant Abundance Research Articles

Diversity and Abundance of Ants from Tehsil Nerwa of District Shimla, Himachal Pradesh, India

The present study focused on diversity, abundance and functional groups of ants from Tehsil Nerwa of District Shimla, Himachal Pradesh. A total of 693 ant specimens representing 33 species belonging to 22 genera of 4 subfamilies were collected. Myrmicinae is the most diverse and abundant subfamily. Dolichoderinae is the least diverse subfamily while Ponerinae is the least abundant subfamily. During this study also reports range extension of 3 invasive species. 2 Species are endemic to the region. In this study seven functional groups of ants were identified. These are: “Generalized Myrmicinae”, “Opportunists”, “Subordinate Camponotini”, “Hot climate Specialists”, “Cold climate Specialists”, “Cryptic Species”, and “Specialist Predators”. The area is very susceptible to anthropogenic activity, as indicated by the prevalence of invasive species there. Therefore, some stringent measures should be taken to preserve the deteriorating ecosystem of the study area.

Reaction of Wood Ants to a Large-Scale European Spruce Bark Beetle Outbreak in Temperate Forests

In the Białowieża Forest, Norway spruce is the preferred host tree species for wood ants, both in coniferous and mixed stands; thus, spruce mortality as a consequence of a continuous spruce bark beetle outbreak in the Białowieża Forest since 2012 could have severe consequences for wood ant colonies, as well as their vitality and distribution. The main aim of this study was to assess whether the bark beetle outbreak had any effects on wood ant nest density and abundance and whether we could find any factors affecting the dead spruce distribution around ant nests. A re-inventory of active and abandoned wood ant nests in our study area was conducted from April to July 2022, using the same procedure as the previous inventory performed in 2016. The wood ant nest density was 0.11 per ha and remained practically the same relative to that determined in 2016. Our results indicate that, despite the importance of spruce for wood ants, in situations when only part of the spruce trees die, natural forest disturbances such as bark beetle outbreaks can actually have positive effects because more light can reach the forest floor, thereby promoting the establishment of new nests.

Continuous measurement of red wood ant (Formica rufa) outdoor behaviour using passive acoustic monitoring

Ants serve as ecosystem engineers that maintain important ecological processes within forests. Given their ecological importance, it is a clear scientific shortcoming that we lack non-invasive methods to survey their behaviour inside common opaque habitats such as mounds, litter, and soil. In this study, we assess if acoustic signals from red wood ant (Formica rufa) mounds are useful to infer temporal changes in ant activity within forested ecosystems. We found that acoustic indices used previously as a proxy for soil fauna in soil ecological studies (Acoustic Complexity Index, Bioacoustic Index) can indeed separate sounds generated by the ant's daily routines (biophony) from other forest sounds. Yet, we also show that these indices are problematic proxies for soil diversity as they increase not only due to an increased number of species but also due to an increased number of the same species. Acoustic measures that incorporated the strength of acoustic signals, Average Power Density (APD) and Peak Power Density (PPD) also increased with increasing ant abundance and constituted the conceptually best proxy for ant activity. For example, the PPD could i) track diurnal changes in Formica rufa activity with a high temporal resolution (minutes) and ii) detect altered behavioural responses to temperature changes. We conclude that microphones detecting biophony can provide high-resolution information about in situ ant behaviours in forested ecosystems. Thus, passive acoustics monitoring offers a promising avenue as a non-invasive monitoring tool for soil macrofauna studies.

Tree species richness suppresses red imported fire ant invasion in a subtropical plantation forest

Abstract The ecological resistance to the invasion of alien species has been extensively researched at the within‐trophic level; however, the effect of cross‐trophic interactions remains largely unknown. The red imported fire ant (RIFA, Solenopsis invicta) is a globally invasive species, and a cross‐trophic interaction study between RIFAs and plants may provide a more comprehensive understanding and management of its invasion. We hypothesized that the diversity of trees, which are the primary producers supporting terrestrial ecosystems, could suppress the invasion of omnivorous RIFAs by regulating food resources (e.g. plants and arthropods) and the microenvironment (e.g. soil microclimate) as well as enhancing competition with other carnivorous ants. To test this hypothesis, we investigated RIFA abundance and mound numbers across tree species richness gradients in a subtropical plantation forest. Using structural equation models, we discovered that tree species richness had contrasting effects on RIFA abundance and mound numbers. RIFA abundance directly decreased with higher tree species richness because of the dilution effect (i.e. lower abundance of preferred tree species). In contrast, RIFA mound numbers indirectly increased with tree species richness via an increase in arthropod abundance (excluding ants) (i.e. more ample food resources for RIFA). Moreover, warmer soil temperatures decreased RIFA abundance, whereas other carnivorous ant species richness and abundance negatively affected RIFA abundance and mound numbers. Synthesis and applications: Our findings demonstrate that the ecological resistance to RIFA invasion is influenced by tree species richness in a complex manner; specifically, the relative strengths of the effects of tree species characteristics, native competitors and environmental conditions are likely to impact the power of ecological resistance. This highlights the importance of cross‐trophic interactions underlying the resistance of complex ecosystems to alien species invasion; therefore, maintaining diverse tree communities in controlled systems (e.g. suburban and urban green spaces) should be viewed as a potential strategy for controlling RIFA invasion.

Delay impacts of ant nests on plant reproductive phenology in a temperate steppe.

Increasing ant abundance associated with climate warming has been observed in temperate ecosystems. However, how enhanced ant activity affects plant development and phenology remains unclear. In this study, individuals of a perennial forb (Potentilla tanacetifolia) during flowering with and without an ant (Proformica) nest were marked to explore the impacts of ant nests on plant growth and phenology in a temperate steppe on the Mongolian Plateau. Ant nests delayed the start and end flowering dates simultaneously and, consequently, had no effect on flowering duration. However, presence of an ant nest postponed the fruiting date of individuals. Nests further increased numbers of aborted flowers and thus decreased fruit set. These observations suggest that the delayed flowering phenology disrupted synchrony between plant reproduction and pollinators and thus reduced pollination efficiency under ant nests. Given the increasing abundance of ants with rising temperatures under climate warming, plant delayed reproductive phenology and reduced reproductive output will potentially have negative consequences for plant fitness and plant-arthropod interactions, with consequent impacts on resistance and resilience of perennial species in temperate steppes under climate change.

Mitochondrial uncoupling caused by a wide variety of protonophores is differently sensitive to carboxyatractyloside in rat heart and liver mitochondria

Mitochondrial uncoupling by small-molecule protonophores is generally accepted to proceed via transmembrane proton shuttling. The idea of facilitating this process by the adenine nucleotide translocase ANT originated primarily from the partial reversal of the DNP-induced mitochondrial uncoupling by the ANT inhibitor carboxyatractyloside (CATR). Recently, the sensitivity to CATR was also observed for the action of such potent OxPhos uncouplers as BAM15, SF6847, FCCP and niclosamide. Here, we report measurements of the CATR effect on the activity of a large number of conventional and novel uncouplers in isolated mammalian mitochondria. Despite the broad variety of chemical structures, CATR attenuated the uncoupling efficacy of all the anionic protonophores in rat heart mitochondria with high abundance of ANT, whereas the effect was much less pronounced or even absent, e.g. for SF6847, in rat liver mitochondria with low ANT content. The fact that the uncoupling action is tissue specific for a broad spectrum of anionic protonophores is highlighted here for the first time. Only with the cationic uncoupler ellipticine and the channel-forming peptide gramicidin A, no sensitivity to CATR was found even in rat heart mitochondria. By contrast, with the recently described ester-stabilized ylidic protonophores [Kirsanov et al. Bioelectrochemistry 2023], the stimulating effect of CATR was discovered both in liver and heart mitochondria.

Ants and predators cope with pest pressures by interacting with the surrounding vegetation at low spatial scales

AbstractBiological control of pests can be enhanced by the presence of semi‐natural habitats within agricultural landscapes. However, this assumption remains controversial due to inconsistencies related to the type of agroecosystems and the natural enemies studied. Within olive orchards, there is a lack of information regarding the interaction among natural enemies and their relation with habitat structure to control pests at the landscape scale. Here, we investigate the effects of the natural habitat on the pest, pest damage and the interaction of pests and natural enemies – using a trophic guild approach, in organic olive orchards. For this, we decomposed the natural habitats into vegetation structures and analysed their effects with a multi‐scale perspective. Our results show that (1) greater proportions of natural habitats increase the abundance of ants (omnivores) and predators and diminish pest pressures – reducing the impact of Prays oleae on olive fruits. (2) Vegetation structures within natural habitats were grouped, based on their effects, into three main vegetation groups: grassland and forest, scrublands and olive trees. However, the dense scrubland and the dense forest improve the abundance of natural enemies that are linked to pest damage the most. (3) Prays oleae increases in landscapes dominated by low numbers of patches that are highly aggregated. Conversely, ants and predators increased in landscapes dominated by high numbers of patches that have a less edge‐resembling shape. (4) Within the olive canopy, the abundance of lacewing larvae and salticid spiders is related to lower pest damage and a reduction in P. oleae adults respectively. However, when ants and predators interact with the natural habitat, they can cope with pest pressures without the need for high abundances, supporting ‘the more‐effective natural enemy hypothesis’ in agroecosystems.

Discovering Native Ant Species with the Potential to Suppress Red Imported Fire Ants.

Native ants have long been considered for their potential to suppress the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), a highly invasive and destructive species. However, the knowledge in this field is limited to behavioral observations of a few related native ants. In this study, by setting up a series of ant combinations of three native ants, i.e., Monomorium chinense Santschi, the robust crazy ant Nylanderia bourbonica Forel, and Iridomyrmex anceps Roger, with S. invicta, we observed the aggression levels and mortality rates. Using baited vials, we also investigated the abundance of native ants in four types of habitats in Eastern China that are preferred by S. invicta (woodland, green belts on roadsides, grassland, and farmland), as well as their seasonal abundance when co-existing with S. invicta and their spatial distribution before and after control of S. invicta. We found that M. chinense and N. bourbonica show a degree of aggression towards S. invicta and can kill substantial proportions of S. invicta under laboratory conditions, but I. anceps does not. Both M. chinense and N. bourbonica can occur in each type of habitat investigated and are more abundant in green belts (particularly lawns with turf) and grasslands relative to other habitats. In grasslands with S. invicta, M. chinense maintained a low density before early July; however, its abundance increased thereafter and reached a peak in September. N. bourbonica also had a low density early in the season and increased steadily from April. Its abundance began to decrease substantially from November. In grasslands invaded by S. invicta, both M. chinense and N. bourbonica were restricted to sites close to the margins before S. invicta was controlled; however, they spread to a larger range within a few weeks after control of S. invicta. In conclusion, M. chinense and N. bourbonica have the potential to suppress S. invicta invasion in habitats that are abundant with these two native ants.

Testing the joint effects of arbuscular mycorrhizal fungi and ants on insect herbivory on potato plants

Main conclusionAnts, but not mycorrhizae, significantly affected insect leaf-chewing herbivory on potato plants. However, there was no evidence of mutualistic interactive effects on herbivory.Plants associate with both aboveground and belowground mutualists, two prominent examples being ants and arbuscular mycorrhizal fungi (AMF), respectively. While both of these mutualisms have been extensively studied, joint manipulations testing their independent and interactive (non-additive) effects on plants are rare. To address this gap, we conducted a joint test of ant and AMF effects on herbivory by leaf-chewing insects attacking potato (Solanum tuberosum) plants, and further measured plant traits likely mediating mutualist effects on herbivory. In a field experiment, we factorially manipulated the presence of AMF (two levels: control and mycorrhization) and ants (two levels: exclusion and presence) and quantified the concentration of leaf phenolic compounds acting as direct defenses, as well as plant volatile organic compound (VOC) emissions potentially mediating direct (e.g., herbivore repellents) or indirect (e.g., ant attractants) defense. Moreover, we measured ant abundance and performed a dual-choice greenhouse experiment testing for effects of VOC blends (mimicking those emitted by control vs. AMF-inoculated plants) on ant attraction as a mechanism for indirect defense. Ant presence significantly reduced herbivory whereas mycorrhization had no detectable influence on herbivory and mutualist effects operated independently. Plant trait measurements indicated that mycorrhization had no effect on leaf phenolics but significantly increased VOC emissions. However, mycorrhization did not affect ant abundance and there was no evidence of AMF effects on herbivory operating via ant-mediated defense. Consistently, the dual-choice assay showed no effect of AMF-induced volatile blends on ant attraction. Together, these results suggest that herbivory on potato plants responds mainly to top-down (ant-mediated) rather than bottom-up (AMF-mediated) control, an asymmetry in effects which could have precluded mutualist non-additive effects on herbivory. Further research on this, as well as other plant systems, is needed to examine the ecological contexts under which mutualist interactive effects are more or less likely to emerge and their impacts on plant fitness and associated communities.

Comparing Ant Activity and Plants Bearing Extrafloral Nectaries in Rockland Habitats of the Florida Keys with Those of the Everglades and the Bahamas

Rocklands are present in South Florida, both on the peninsula and in the Keys. Previous work has shown that extrafloral nectaries on pine rockland plants in the Florida Everglades and surrounding areas play a role in attracting ant protectors. Species with nectaries are more abundant and ant activity greater in more recently burned pine rockland habitats compared with longer undisturbed rockland hammock forest. The floristic composition and prevailing climate of Keys rocklands differs substantially from those on the mainland, so we sought to investigate ant activity and the abundance of plants with extrafloral nectaries in Big Pine Key rockland habitats. Standard baiting methods were used to assess ant abundance and potential predation activity in hardwood hammock, shrubby pine rockland, and open pine rockland sites. Ant activity was the lowest in open pine rockland, greatest in hardwood hammock, and intermediate in shrubby pine rockland, the opposite of what has been observed in previous studies in southern peninsular Florida and on Andros, Bahamas. Sampling vegetation at these same sites revealed a larger proportion of plant species with extrafloral nectaries in the pine rocklands than the hammock, as observed previously in Everglades habitats. Possible reasons for differences in ant activity in Keys rockland habitats are discussed.

Ant Species Richness and Diversity in Selected Habitats in Chavara Panchayath, Kollam District, Kerala, India

Ants are an important part of the ecosystem not only because of their huge biomass but also because of their role in the ecosystem. The aim of this study is to address the diversity and abundance of ants in Chavara panchayat, Kollam district, Kerala. The study records a total of 16 ant species belongs to 1 family, 7 tribes, and 3 subfamilies in Chavara panchayat, which provides a brief scenario and improves our knowledge the diversity and distribution of the myrmecofauna in the region. The subfamilies include Formicinae (4 genera and 7 species), Myrmicinae (5 genera and 6 species), and Ponerinae (3 genera and 3 species). Formicinae was the most diverse subfamily, Myrmicinae was the most abundant tribe, and Ponerinae was the least abundant and most diverse subfamily. Biodiversity indices show that the study area has high biodiversity and species richness.

Circadian pattern in attendance of aphid colonies by ants

Ant-attendance of aphids is one of the subjects of interest in ecological studies as a reciprocal service providing benefits to both groups involved. The behavioural patterns in this relation depend on many factors, e.g. biology of the species involved, aphid host plants, activity of natural enemies and abiotic factors. In this respect, the circadian pattern of ant-attendance was almost unknown. The paper presents the results of the pattern of such circadian activity of ants Lasius niger and L. emarginatus attending six aphid species (Panaphis juglandis, Aphis grossulariae, A. urticata, A. umbrella, Myzus persicae and Aphis fabae) feeding on various types of plants and having various dependence of trophobiosis. The highest number of ant workers in aphid colonies was observed at night and dawn, while the lowest was just after solar noon. The circadian pattern of ant activity strongly depends on the weather, especially temperature and relative humidity, with the highest abundance of ants during humid and cool weather. The possible interconnection between the temperature-dependent activity of ants and the water-dependent physiological condition of certain plants is discussed and indicated as an explanation. The issue of possible work division among ant workers attending aphids as an explanation of the observed pattern of activity remains open.

Biochar soil addition alters ant functional traits as exemplified with three species

The response of soil microorganisms and plants in soil ecosystems to biochar is well recognised. However, biochars’ impact on large soil animal, such as ants, is inadequately understood, with only limited studies focusing on the abundance and mortality rates of some specific ant species. In this study, soil physicochemical properties, and ant community diversity and functional characteristics were compared between experimental plots with and without biochar application. No significant differences in soil (soil physicochemical properties) or ants (ant community richness, species abundance, and morphological characteristics) were observed between the two plots before biochar application. However, the biochar-treated plot soil surface temperatures, pH, and soil water content were significantly higher after 48 weeks. Biochar application promoted Cardiocondyla nuda (by 426%) and Formica japonica abundance (by 93%), but decreased Solenopsis invicta invasive ant species richness (by 54%), consistent with the fact that changes in soil properties were more beneficial to the former two species. In addition, in biochar-treated plots, F. japonica and S. invicta generally showed larger body size (18% and 6.7%), larger eyes (2.7% and 4.0%), and longer femurs (6.3% and 7.9%), which enabled them to respond better to potential barriers, such as plants. Our results highlighted that, besides species abundance and community structure, certain ant functional morphological indicators were also informative in evaluating biochar ecological implications.Graphical abstract

Ants of Uluru-Kata Tjuta National Park in arid Australia: Diversity, faunistic composition and habitat associations

Inland Australia supports by far the world's most diverse arid-adapted ant fauna, but there are no published studies of regional ant faunas from the central arid zone. Here we describe the ants collected by pitfall trapping at 22 sites in World Heritage-listed Uluru-Kata Tjuta National Park (300 mm mean annual rainfall), representing all major vegetation types from spinifex grasslands to eucalypt woodlands. A total of 154 (mostly undescribed) ant species from 26 genera were recorded, with the richest genera being Melophorus (30 species), Monomorium (26), Iridomyrmex (18) and Camponotus (12). The pattern of species accumulation suggests that many more species remain to be collected from the Park, and we estimate that the total fauna consists of around 300 species. The most abundant ants were species of Iridomyrmex (collectively contributing 76% of all ants collected), as is the case throughout arid Australia. Species of Monomorium and Melophorus were also highly abundant. No exotic species were recorded. Ant species composition was strongly related to vegetation type, with a particular distinction between the various grasslands on one hand, and woodlands on the other. Unexpectedly, species richness was higher in structurally simple spinifex grasslands than in eucalypt woodlands. The woodland fauna lacks many taxa characteristic of such habitats in similarly arid regions of southern Australia, which we attribute to remoteness and small patch size. Uluru-Kata Tjuta National Park supports an extremely diverse ant fauna, but surveys of other areas are required for an improved understanding of patterns of ant biodiversity in Australia's central arid zone.

Ants (Hymenoptera: Formicidae) and termites (Blattodea: Termitoidae) in the diet of wild white-bellied pangolin (Phataginus tricuspis) in forest-savanna habitats of Cameroon.

The white-bellied pangolin Phataginus tricuspis (Rafinesque 1821) is a semiarboreal species occurring in tropical sub-Saharan Africa. It is the world's most trafficked African pangolin species based on volumes recorded in seizures. Reintroduction of confiscated live pangolins and ex-situ rearing are being explored worldwide as a conservation action. However, the husbandry of seized animals is challenging as the diet of the white-bellied pangolin is poorly known and little studied. We analyzed the stomach contents of dead white-bellied pangolins from two forest-savanna protected areas. Stomach content samples from 13 white-bellied pangolin specimens contained ~165,000 Arthropoda, mostly Hymenoptera (60.34%) and Blattodea (39.66%). Overall, we identified 39 termite and 105 ant species consumed as prey by pangolins. Individual pangolins examined had fed on a maximum of 31 ant species and 13 termite species. The termite and ant species richness varied significantly across the pangolins'last consumed meal. We recorded 24 ant genera dominated by Crematogaster (relative importance [RI] = 17.28). Out of 18 termite genera recorded, the genus Pseudacanthotermes (RI = 17.21) was the most important prey. Ten ant species were preferentially eaten by white-bellied pangolin, with Crematogaster acis being the most common prey species. Four species of termite were most frequently eaten with Pseudacanthotermes militaris being the most abundant. The mean abundance of ants and termites varied among pangolin individuals. The season did not influence the mean abundance of termites eaten by pangolin individuals. However, ant abundance in stomach contents was significantly higher in the dry season. An improved understanding of pangolin feeding behavior and prey selection may help inform conservation husbandry efforts. For example, nutritional analysis of the food eaten by wild pangolins can guide the development of nutritional diets for captive pangolins.

Different feeding preferences for macronutrients across seasons and sites indicate temporal and spatial nutrient limitation in the black bog ant.

How the resource use by consumers vary in different environments and time scales is one of the fundamental ecological questions. Replicated field studies are rare, however; so the extent to which nutrient use varies and why is uncertain. We studied an endangered tyrphobiotic species, the black bog ant (Formica picea), and its feeding preferences in temperate peatlands. We conducted a baiting experiment at three different sites with high nest densities, repeated over threeyears and three periods of growing season. Preferences for three main macronutrients (carbohydrates, proteins and lipids) were assessed. We hypothesised that if nutrient limitation plays a role, ants will have an increased need for proteins and lipids in early seasons when brood is raised, while carbohydrates use will increase in late seasons. We also expected that site identity would influence nutrient preferences, but not year. Our results supported the nutrient limitation hypothesis for proteins that were consumed more in the early season. In contrast, preference for carbohydrates was rather high and did not increase consistently through season. Although the occupancy of lipid baits was low overall, it increased at colder temperatures, in contrast to carbohydrate and protein baits. Nutrient preferences varied more among sites than years, with the lowest nutrient use observed in a diverse fen-meadow, consistent with the nutrient limitation hypothesis. Year affected ant abundance, but not bait occupancy. Our results suggest that black bog ants flexibly adapt their diet to environmental conditions and that an interplay between nutrient limitation and climate determines their feeding behaviour.

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.

New Canadian amber deposit fills gap in fossil record near end-Cretaceous mass extinction

Amber preserves an exceptional record of tiny, soft-bodied organisms and chemical environmental signatures, elucidating the evolution of arthropod lineages and the diversity, ecology, and biogeochemistry of ancient ecosystems. However, globally, fossiliferous amber deposits are rare in the latest Cretaceous and surrounding the Cretaceous-Paleogene (K-Pg) mass extinction.1,2,3,4,5 This faunal gap limits our understanding of arthropod diversity and survival across the extinction boundary.2,6 Contrasting hypotheses propose that arthropods were either relatively unaffected by the K-Pg extinction or experienced a steady decline in diversity before the extinction event followed by rapid diversification in the Cenozoic.2,6 These hypotheses are primarily based on arthropod feeding traces on fossil leaves and time-calibrated molecular phylogenies, not direct observation of the fossil record.2,7 Here, we report a diverse amber assemblage from the Late Cretaceous (67.04± 0.16 Ma) of the Big Muddy Badlands, Canada. The new deposit fills a critical 16-million-year gap in the arthropod fossil record spanning the K-Pg mass extinction. Seven arthropod orders and at least 11 insect families have been recovered, making the Big Muddy amber deposit the most diverse arthropod assemblage near the K-Pg extinction. Amber chemistry and stable isotopes suggest the amber was produced by coniferous (Cupressaceae) trees in a subtropical swamp near remnants of the Western Interior Seaway. The unexpected abundance of ants from extant families and the virtual absence of arthropods from common, exclusively Cretaceous families suggests that Big Muddy amber may represent a yet unsampled Late Cretaceous environment and provides evidence of a faunal transition before the end of the Cretaceous.

Temporal Variability in Weaver Ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae) Nest Characteristics in Selected Host Plants

Weaver ants (Oecophylla smaragdina and O. longinoda) are famous for their impressive nest constructions where they weave together living leaves on their host plants. Also, they are known to protect tropical tree crops against insect pests and are thus being utilized for biological control. To optimize their use, nest numbers have been used to track weaver ant abundances in plantation, assuming the number of nests reflects ant numbers. In this study we compared nest size, the density of ants and the proportion of workers in nests between three host plants (cashew, citrus and mango) and between two seasons (rainy and dry). Nest size, ant density and worker proportion all differed between host species, whereas only nest size and worker proportion showed seasonal differences and only on mango and citrus, respectively. On hosts with smaller nests (in increasing size order: cashew, citrus mango), ant densities in the nests were higher, and the proportion of workers in the nests seemed to increase during seasons where food production on host trees decreased, or on hosts where more trophobionts were cultured inside nests. These results have implications for the development of methods used to estimate ant numbers and they raise interesting questions about the function of weaver ant nests.

Agricultural landscape composition alters ant communities in maize fields more than plant diversity enrichment

Abstract. Pasaribu DN, Rizali A, Tarno H, Priawandiputra W, Johannis M, Buchori D. 2024. Agricultural landscape composition alters ant communities in maize fields more than plant diversity enrichment. Biodiversitas 25: 205-213. Fragmented natural habitats in human-modified landscapes play a crucial role in conserving biodiversity. Ants, as keystone species, are integral to terrestrial ecosystems, making it essential to comprehend the factors influencing their survival. This study investigates the impact of agricultural landscape composition and plant diversity enrichment (flowering plants) management on shaping ant communities in maize (Zea mays L.) fields. The research occurred in maize fields surrounded by other crops, semi-natural habitats, and housing areas in Malang District, East Java, Indonesia. The four agricultural areas were divided into control and treatment plots, considering landscape composition parameters, particularly Class Area (CA) and the Number of Patches (NP), measured within a 500 m radius. The landscape around the maize fields was characterized by manually digitizing land use. Six types of plant diversity enrichment were employed in this study: wild cosmos (Cosmos caudatus), white buttercup (Turnera subulata), sunflower (Helianthus annuus), long bean (Vigna unguiculata), ornamental bean (Arachis pintoi), and coral vine (Antigonon leptopus). The study was divided into the dry season (April-July 2022) and the wet season (September-December 2022). Ant sampling was conducted using pitfall traps and, based on generalized linear models, revealed that plant diversity enrichment management did not affect species richness, abundance, or composition of ants. Landscape composition positively influenced ant species richness but negatively impacted species composition, particularly the number of semi-natural habitat patches. Maize crop age also positively influenced ant species richness but negatively affected beta diversity. Wet season was also found to have a negative effect on beta diversity. In conclusion, the proportion of semi-natural habitats in agricultural landscapes and crop age contribute significantly to species richness and species composition of ants.