Ant Camponotus Research Articles

Ant-Mediated Nectar Robbing from the Chilean Firetree Embothrium coccineum (Proteaceae): No Effect on Seed Production

Nectar robbing by the ant Camponotus distinguendus was observed in flowers of Embothrium coccineum (Proteaceae), a tree mainly pollinated by hummingbirds. We hypothesized that robbing would reduce the amount of nectar, affecting the foraging behaviour of floral visitors and reducing seed production. Nectar robbing affected one-third of mature tree blossoms and 93.3% of trees. This reduced the amount of nectar to about half. Foraging behaviour of floral visitors included pollinating visits to consume nectar and pollen, primary and secondary nectar robbing, and nectar theft. We found no effect of nectar robbing by C. distinguendus on seed production in E. coccineum, which was sparse and completely dependent on legitimate pollinator visits, mostly performed by the green-backed firecrown Sephanoides sephaniodes. Determining the effects of nectar robbing by ants on the reproduction of plants is important to understand the dynamics of plant-animal interactions in the temperate forests of Chile.

Ant–plant relationships in the canopy of an Amazonian rainforest: the presence of an ant mosaic

Using different techniques to access the canopy of an Amazonian rainforest, we inspected 157 tree crowns for arbo-real ants. Diversity statistics showed that our study sample was not representative of the tree and ant populations due to their high diversity in Amazonian rainforests, but permitted us to note that a representative part of territorially dominant arboreal ant species (TDAAs) was inventoried. Mapping of TDAA territories and use of a null model showed the presence of an ant mosaic in the upper canopy, but this was not the case in the sub-canopy. Among the TDAAs, carton-nesting Azteca dominated (52.98% of the trees) whereas ant-garden ants (Camponotus femoratus and Crematogaster levior), common in pioneer formations, were secondarily abundant (21.64% of the trees), and the remaining 25.37% of trees sheltered one of 11 other TDAAs. The distribution of the trees forming the upper canopy influences the structure of the ant mosaic, which is related to the attractiveness of some tree taxa for certain arboreal ant species and represents a case of diffuse coevolution. ADDITIONAL KEYWORDS: ant mosaics-host tree attractiveness-indicators of disturbance-pristine Amazonian rainforest-territoriality.

Suppressing tawny crazy ant (Nylanderia fulva) by RNAi technology.

The tawny crazy ant (Nylanderia fulva) is a new invasive pest in the United States. At present, its management mainly relies on the use of synthetic insecticides, which are generally ineffective at producing lasting control of the pest, necessitating alternative environmentally friendly measures. In this study, we evaluated the feasibility of gene silencing to control this ant species. Six housekeeping genes encoding actin (NfActin), coatomer subunit β (NfCOPβ), arginine kinase (NfArgK), and V-type proton ATPase subunits A (NfvATPaseA), B (NfvATPaseB) and E (NfvATPaseE) were cloned. Phylogenetic analysis revealed high sequence similarity to homologs from other ant species, particularly the Florida carpenter ant (Camponotus floridanus). To silence these genes, vector L4440 was used to generate six specific RNAi constructs for bacterial expression. Heat-inactivated, dsRNA-expressing Escherichia coli were incorporated into artificial diet. Worker ants exhibited reduced endogenous gene expression after feeding on such diet for 9 d. However, only ingestion of dsRNAs of NfCOPβ (a gene involved in protein trafficking) and NfArgK (a cellular energy reserve regulatory gene in invertebrates) caused modest but significantly higher ant mortality than the control. These results suggest that bacterially expressed dsRNA can be orally delivered to ant cells as a mean to target its vulnerabilities. Improved efficacy is necessary for the RNAi-based approach to be useful in tawny crazy ant management.

Interactions among attending ants, brown-citrus aphids, and ladybugs in plants of Citrus sinensis

Attending ants promote colony survivorship and reproduction of aphid colonies, mainly by protection against natural enemies. However, very few papers are about the assessment of the effect of attending ants directly on individuals of aphids without the presence of other organisms. In this article, a review of the main papers that had assessed the effect of the attendant ant Camponotus punctulatus (Formicidae) on the table of life of the brown-citrusaphid Toxoptera citricidus (Hemiptera: Aphididae) that grows in plants of Citrus sinensis (Rutaceae) without the presence of natural enemies. The ant behavior in the presence of adults and immature individuals of the ladybug Cycloneda sanguinea (Coleoptera: Coccinellidae) in colonies kept on Poncirus trifoliata was also evaluated. Nymph survivorship, adult total fertility, reproductive and post-reproductive period were not affected by the attending ants. The elevation of mean and daily fecundity of the aphids attending on the first days has great importance in the population growth. Ant behavior does not depend on the ladybug sex, nor on the colony size, so that ladybug larvae are more tolerated than adults in the aphid colonies. We registered that the behaviour of the aphids is similar independently of their sex and colony size, whereas ladybug larvae are more tolerated than their adults in aphid colonies.Keywords: survivorship, fecundity, table of life, population growth.

High-Quality Genome Assemblies Reveal Long Non-coding RNAs Expressed in Ant Brains

SUMMARYAnts are an emerging model system for neuroepigenetics, as embryos with virtually identical genomes develop into different adult castes that display diverse physiology, morphology, and behavior. Although a number of ant genomes have been sequenced to date, their draft quality is an obstacle to sophisticated analyses of epigenetic gene regulation. We reassembled de novo high-quality genomes for two ant species, Camponotus floridanus and Harpegnathos saltator. Using long reads enabled us to span large repetitive regions and improve genome contiguity, leading to comprehensive and accurate protein-coding annotations that facilitated the identification of a Gp-9-like gene as differentially expressed in Harpegnathos castes. The new assemblies also enabled us to annotate long non-coding RNAs in ants, revealing caste-, brain-, and developmental-stage-specific long non-coding RNAs (lncRNAs) in Harpegnathos. These upgraded genomes, along with the new gene annotations, will aid future efforts to identify epigenetic mechanisms of phenotypic and behavioral plasticity in ants.

Red imported fire ants (Solenopsis invicta) and seasonality influence community refuge use

Refuges are fundamental to animal ecology as refuge availability affects many levels of biological organization—from the behavior and physiology of individuals to the interspecific dynamics of a community. Although frequently studied in the context of predator–prey interactions, refuges may also mediate interspecific competition between native and invasive taxa given the role of refuges as a valuable resource. Because interspecific interactions (e.g., competition and predation) can be modulated by temporal and biotic (e.g., trophic level) factors, we used a manipulative approach to investigate community-wide refuge-use patterns in the context of two important ecological factors: invasive species and seasonality. We surveyed refuge (artificial cover object) use of ants and vertebrates in a forest community for 2 years, and we systematically suppressed an established invasive species (red imported fire ant, Solenopsis invicta) to examine its impact on community refuge use. Native Camponotus ants appeared to co-exist and share refuges with S. invicta, but we found evidence for a negative effect of S. invicta on vertebrate refuge use that was also influenced by season. Vertebrates were more abundant under refuges undergoing suppression of S. invicta, and they were less abundant under refuges during the fall (the season characterized by the highest occupancy of refuges by S. invicta). Thus, researchers must continue to examine the entire community and to incorporate the effects of season when assessing the impact of invasive species (e.g., at our site, a survey conducted only in the summer or only on native ants would have indicated a negligible effect of S. invicta on community refuge use).

Transovarian Transmission of Blochmannia and Wolbachia Endosymbionts in the Neotropical Weaver Ant Camponotus textor (Hymenoptera, Formicidae).

Camponotus is a hyper-diverse ant genus that is associated with the obligate endosymbiont Blochmannia, and often also with Wolbachia, but morphological studies on the location of these bacteria in the queen's ovaries during oogenesis remain limited. In the present study, we used the Neotropical weaver ant Camponotus textor to characterize the ovary using histology (HE) techniques, and to document the location of Blochmannia and Wolbachia during oogenesis through fluorescence in situ hybridization (FISH). This is the first morphological report of these two bacteria in the same host with polytrophic meroistic ovaries and reveals that Blochmannia is found inside late-stage oocytes and Wolbachia is associated with the nuclei of the nurse cells. Our results provide insights into the developmental sequence of when these bacteria reach the egg, with Blochmannia establishing itself in the egg first, and Wolbachia only reaching the egg shortly before completing egg development. Studies such as this provide understanding about the mechanisms and timing of the establishment of these endosymbionts in the host.

<b>On the reproductive ecology of <I>Premna latifolia</I> L. and <I>Premna tomentosa</I> Willd. (Lamiaceae)</b>

Premna latifolia and Premna tomentosa shed their foliage during winter but produce foliage at different periods to avoid competition for nutrients, P. latifolia during the dry season while P. tomentosa during the wet season. Flowering also occurs at different seasons, P. latifolia during the wet season and P. tomentosa during the dry season. The flowering period of P. latifolia is comparatively longer than P. tomentosa; however, both of them display profuse flowering for 2–3 weeks only. The flowers are of gullet type, weakly bilabiate, and the stamens and stigma are situated near the upper corolla lip and are dichogamous, herkogamous and facultatively xenogamous in both species. In P. latifolia, the pollinators are wasps and butterflies while in P. tomentosa, in addition to wasps and butterflies, the bees and flies are also pollinators. Camponotus ants rob the nectar of P. latifolia by removing the entire corolla together with stamens and sometimes also with the style and stigma. Both the species display ornithochory, anthropochory and anemochory. The seeds germinate during wet season in both the species irrespective of their time of dispersal but their continued growth depends on the soil nutrient and moisture environment.

Ecology and field biology of two dominant Camponotus ants (Hymenoptera: Formicidae) in the Brazilian savannah

Camponotus renggeri and C. rufipes are very abundant in Brazilian cerrado savannah, where they feed extensively on liquid rewards and commonly associate with plants bearing extrafloral nectaries and honeydew-producing insects. Here, we provide a qualitative and quantitative field account on the natural history and ecology of these two ant species. The study was carried out in a cerrado reserve in south-eastern Brazil across a rainy/hot season (summer) and a dry/cold season (winter). The ants were found in two vegetation physiognomies: all nests of C. rufipes were located in the cerrado sensu stricto (scrub of shrubs and trees, 3–8 m tall), whereas C. renggeri occurred mostly in the cerradão (forest with more or less merging canopy, 10–12 m tall). Both species nested in fallen or erect dead trunks, as well as underground. In addition, C. rufipes built nests using dead plant material arranged or not around shrub bases. Colonies of C. rufipes were generally more populous than those of C. renggeri, and both species had colonies with more than one dealated queen. Both species were active mainly at night and foraged for resources near their nests, mainly extrafloral nectar and hemipteran honeydew (aphids and mealybugs). The average size of the home ranges of C. renggeri in cerrado sensu stricto and cerradão varied from ≈ 2.8 to 4.0 m2 and apparently were not affected by season. In C. rufipes, however, foraging grounds in cerrado sensu stricto showed a twofold increase from dry/cold (≈ 4.5 m2) to rainy/hot season (≈ 9.8 m2). Our study highlights the importance of natural history data to understand the foraging ecology and role of these ants in cerrado savannah.

Ecology and field biology of two dominant Camponotus ants (Hymenoptera: Formicidae) in the Brazilian savannah

Camponotus renggeri and C. rufipes are very abundant in Brazilian cerrado savannah, where they feed extensively on liquid rewards and commonly associate with plants bearing extrafloral nectaries an...

Carpenter ants use diverse antennae sampling strategies to track odor trails.

Directed and meaningful animal behavior depends on the ability to sense key features in the environment. Among the different environmental signals, olfactory cues are critically important for foraging, navigation and social communication in many species, including ants. Ants use their two antennae to explore the olfactory world, but how they do so remains largely unknown. In this study, we used high-resolution videography to characterize the antennae dynamics of carpenter ants (Camponotus pennsylvanicus). Antennae are highly active during both odor tracking and exploratory behavior. When tracking, ants used several distinct behavioral strategies with stereotyped antennae sampling patterns (which we call 'sinusoidal', 'probing' and 'trail following'). In all behaviors, left and right antennae movements were anti-correlated, and tracking ants exhibited biases in the use of left versus right antenna to sample the odor trail. These results suggest non-redundant roles for the two antennae. In one of the behavioral modules (trail following), ants used both antennae to detect trail edges and direct subsequent turns, suggesting a specialized form of tropotaxis. Lastly, removal of an antenna resulted not only in less accurate tracking but also in changes in the sampling pattern of the remaining antenna. Our quantitative characterization of odor trail tracking lays a foundation to build better models of olfactory sensory processing and sensorimotor behavior in terrestrial insects.

Ant-partners play a minor role on occurrence of the myrmecophilous butterfly Leptotes cassius in its host plant

Ant-related oviposition in facultatively myrmecophilous lycaenid butterflies is common, but not universal. In fact, our knowledge of ant-related oviposition in lycaenids is based on some common species (e.g., Rekoa marius, Allosmaitia strophius, Parrhasius polibetes), which limits generalizations about these systems. In this study, we experimentally investigated whether the oviposition pattern of the florivorous lycaenid Leptotes cassius was influenced by the presence of Camponotus ants and whether larvae were attended, rather than attacked, by ants. This might be evidence of myrmecophily. Both L. cassius and Camponotus ants occur on Bionia coriacea, an extrafloral nectaried legume shrub that grows in the Brazilian cerrado. Plants were randomly assigned to ant-present and ant-excluded treatments and were observed twice throughout the short reproductive season. Larvae of L. cassius were tended by ants, whose attendance was characterized by active antennation on the last body segments of the caterpillars. Therefore, Camponotus can be considered a partner of L. cassius. Lycaenid abundance was on average 1.9- and 1.21-fold higher in plants with ants in each sampling period, respectively, indicating a tendency of L. cassius to occur in plants with ants. Nonetheless, results were not statistically significant, suggesting that in this case ants are not a major cue for lycaenid oviposition. In many ant–lycaenid mutualisms, butterfly immatures benefit from reduced parasitism rates. However, no L. cassius immature, regardless of ant presence or absence, was parasitized. Furthermore, larvae may occur inside flower buds that may provide protection from natural enemies; thus, ants may not be required for immature protection.

Streptomyces capitiformicae sp. nov., a novel actinomycete producing angucyclinone antibiotics isolated from the head of Camponotus japonicus Mayr.

A novel actinomycete, designated strain 1H-SSA4T, was isolated from the head of an ant (Camponotus japonicus Mayr) and was found to produce angucyclinone antibiotics. A polyphasic approach was used to determine the taxonomic status of strain 1H-SSA4T. The DNA G+C content of the draft genome sequence, consisting of 11.4 Mbp, was 70.0 mol%. 16S rRNA gene sequence similarity studies showed that strain 1H-SSA4T belongs to the genus Streptomyces with the highest sequence similarity to Streptomyces hygroscopicus subsp. ossamyceticus NBRC 13983T (98.9 %), and phylogenetically clustered with this species, Streptomyces torulosus LMG 20305T (98.8 %), Streptomyces ipomoeae NBRC 13050T (98.5 %) and Streptomyces decoyicus NRRL 2666T (98.4 %). The morphological and chemotaxonomic properties of the strain were also consistent with those members of the genus Streptomyces. A combination of DNA-DNA hybridization experiments and phenotypic tests were carried out between strain 1H-SSA4T and the above-mentioned strains, which further clarified their relatedness and demonstrated that strain 1H-SSA4T could be distinguished from these strains. Therefore, the strain is concluded to represent a novel species of the genus Streptomyces, for which the name Streptomyces capitiformicae sp. nov. is proposed. The type strain is 1H-SSA4T (=CGMCC 4.7403T=DSM 104537T).

Morphology and ultrastructure of Dufour’s and venom glands in the ant Camponotus japonicus Mayr (Hymenoptera: Formicidae)

The Dufour’s and venom glands are two important exocrine glands in ants. In this study, the morphology and fine structure of these two glands are described in the ant Camponotus japonicus Mayr. The Dufour glands have a characteristic bilobed shape and show a difference in size and color between the female castes (minor and major workers, alate and dealate queens). The external surface of Dufour’s gland shows different features among the female castes. It appears more hypertrophied in major workers than in the other castes, indicating for a more pronounced function. The cells of the glandular epithelium in Dufour’s gland are characterized by abundant mitochondria, basal invaginations and developed muscle fibres. The venom gland is morphologically similar in the different female castes, and consists of a venom reservoir, a convoluted gland and a bifurcated free secretory filament, with the convoluted gland appearing as a large cap lying on top of the reservoir. Cells of the convoluted gland and the free secretory filaments contain numerous mitochondria and a prominent end apparatus. The results will contribute to understanding the functional morphology of these glands among the different castes in Camponotus ants.

Evolution of the optimal reproductive schedule in the ant Camponotus (Colobopsis) nipponicus (wheeler): a demographic approach

1. Traits are hypothesised to optimise via natural selection. The schedule of reproduction is an important adaptive trait, but its evolution is difficult to study, as measuring parameters is usually difficult. However, the sufficient amounts of demographic data enable us to estimate these parameters.2. Here, it is shown that the reproductive schedule of the ant Camponotus (Colobopsis) nipponicus is tuned to maximise the lifetime production of alates.3. A colony started its reproduction 4 years after the colony founding, at which time they were far smaller than well‐developed colonies. This contradicts the prediction of the bang‐bang strategy theory. The size distribution of colonies in the study area showed that the mortality of small colonies is much higher than that of large colonies.4. A simulation analysis suggests that the colonies that are smaller than the threshold can still achieve significant improvement in colny survival to the following year by investing all resources in colony growth instead of reproduction. A sensitivity analysis for the starting year of reproduction showed that the observed schedule maximises lifetime alate production. The demographic data suggest a stable population, which is required for optimisation through this maximisation.5. The observed reproductive schedule must be optimised, and the breakdown of the bang‐bang theory is due to higher mortalities during the incipient stage of colonies. This study demonstrates that having enough demographic data creates a useful tool for studying the evolution of life‐history characteristics.

Streptomyces amphotericinicus sp. nov., an amphotericin-producing actinomycete isolated from the head of an ant (Camponotus japonicus Mayr).

A novel actinomycete, designated strain 1H-SSA8T, was isolated from the head of an ant (Camponotus japonicus Mayr) and was found to produce amphotericin. A polyphasic approach was employed to determine the status of strain 1H-SSA8T. Morphological and chemotaxonomic characteristics were consistent with those of members of the genus Streptomyces. The menaquinones detected were MK-9(H6), MK-9(H8) and MK-9(H4). The phospholipid profile consisted of diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine and phosphatidylinositol mannoside. The major fatty acids were identified as iso-C16 : 0, C16 : 0, C15 : 0 and anteiso-C15 : 0. Analysis of the 16S rRNA gene sequence showed that strain 1H-SSA8T belongs to the genus Streptomyces with high sequence similarity to Streptomyces ramulosus NRRL B-2714T (99.2 %). Two tree-making algorithms based on 16S rRNA gene sequences showed that the isolate formed a phyletic line with Streptomyces himastatinicus ATCC 53653T (98.7 %). The MLSA utilizing partial sequences of the housekeeping genes (atpD, gyrB, recA, rpoB and trpB) also supported the position. However, evolutionary distances were higher than the 0.007 MLSA evolutionary distance threshold proposed for species-level relatedness. Moreover, the low level of DNA-DNA relatedness and phenotypic differences allowed the novel isolate to be differentiated from its most closely related strain S. ramulosus NRRL B-2714T and strain S. himastatinicus ATCC 53653T. It is concluded that the organism can be classified as representing a novel species of the genus Streptomyces, for which the name Streptomyces amphotericinicus sp. nov. is proposed. The type strain is 1H-SSA8T (=CGMCC 4.7350T=DSM 103128T).

Disgusting or delicious? Predatory behavior of the hylid frog Phyllodytes luteolus on sympatric ants

ABSTRACT The phytotelm-dwelling frogs from the genus Phyllodytes Wagler, 1830 have been characterized as specialist frogs regarding their diet strategy which is mainly composed by colonial insects. Herein, we used two species of ants (Camponotus sp. and Gnamptogenys sp.) with distinct defensive mechanisms to test the predatory behavior of Phyllodytes luteolus Wied, 1824. The experiment was conducted with frogs inhabiting a patch of 20 bromeliads (Aechmea cf. blanchetiana). Ants were offered randomly to the frogs until we obtained ten observations of predation of each ant species. We observed and recorded the time that P. luteolus needed to keep each ant species inside its mouth before it could ingest it. Predatory behavior was highly distinct. While Camponotus were caught and swallowed within six seconds and without apparent discomfort, individuals of P. luteolus had more difficulty in swallowing Gnamptogenys individuals, the time of manipulation ranging from 57 to 177 seconds. The mean values of time of predation observed in each treatment was highly significant (p<0.001). We conclude that differences found in the time of manipulation are highly correlated with defense mechanisms of each species of ants.

Innate colour preference, individual learning and memory retention in the ant Camponotus blandus.

Ants are a well-characterized insect model for the study of visual learning and orientation, but the extent to which colour vision is involved in these tasks remains unknown. We investigated the colour preference, learning and memory retention of Camponotus blandus foragers under controlled laboratory conditions. Our results show that C. blandus foragers exhibit a strong innate preference for ultraviolet (UV, 365 nm) over blue (450 nm) and green (528 nm) wavelengths. The ants can learn to discriminate 365 nm from either 528 nm or 450 nm, independent of intensity changes. However, they fail to discriminate between 450 nm and 528 nm. Modelling of putative colour spaces involving different numbers of photoreceptor types revealed that colour discrimination performance of individual ants is best explained by dichromacy, comprising a short-wavelength (UV) receptor with peak sensitivity at about 360 nm, and a long-wavelength receptor with peak sensitivity between 470 nm and 560 nm. Foragers trained to discriminate blue or green from UV light are able to retain the learned colour information in an early mid-term (e-MTM), late mid-term (l-MTM), early long-term (e-LTM) and late long-term (l-LTM) memory from where it can be retrieved after 1 h, 12 h, 24 h, 3days and 7 days after training, indicating that colour learning may induce different memory phases in ants. Overall, our results show that ants can use chromatic information in a way that should promote efficient foraging in complex natural environments.

La leña como vía para la introducción de insectos. ¿Cuáles son los riesgos de las invasiones de hormigas en la Patagonia?

Firewood can act as a long-distance dispersal vector for wood-infesting insects both within and among countries. Recently, we detected the alien carpenter ant Camponotus mus in firewood transported from central Argentina to Patagonia. This species generates significant economic losses in its native range and has invader potential. Moreover, global warming and the increasing anthropogenic disturbance in Patagonian ecosystems make them highly susceptible to insect invasions. This is especially alarming considering the current lack of sanitary controls of incoming goods into the region. To prevent insect introductions via firewood, it is crucial to implement a joint effort among the scientific community, control organisms, government and end user.https://doi.org/10.25260/EA.17.27.2.0.478

Overwintering ecology of Philonthus rotundicollis (Coleoptera, Staphylinidae) in the nest of the carpenter ant Camponotus herculeanus on the coast of the Sea of Okhotsk

A widespread rove beetle species, Philonthus rotundicollis, whose distribution range stretches across different climatic zones, including the coldest regions of the Asian northeast, was discovered as an inquiline within the nests of the carpenter ant Camponotus herculeanus on the coast of the Sea of Okhotsk in winter. It remained unclear if the beetles had significant cold-hardiness and whether they overwintered deep in the soil or were confined to particularly warm habitats. To clarify these aspects, the following metrics of cold-hardiness were measured: supercooling point (SCP), freezing point (FP), supercooling capacity (SCP-FP), and temperature minima at the beetles’ overwintering sites. In Ph. rotundicollis, mean SCP was -11.1 ± 0.7°C (ranging from - 7.9 to -18.8°C, n + 15), which was insufficient for successful overwintering even on the coast, since temperature minima in leaf litter during a snow-deficient winter fell to -14°C at the depth of 5 cm and -12°C at 20 cm. The beetles could not burrow deep into stiff soil and made use of crevices in dry peat-like soil layers as well as tunnels of soil- and rootdwelling animals, including carpenter ants. The presence of this rove beetle species in the ant nest was probably due to feeding on ant larvae because, at near-zero temperatures, the activity threshold of the beetles was lower than that of the ants that guarded the larvae.