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Sample records for rasberry crazy ant

  1. Musings on the management of Nylanderia fulva Crazy Ants

    USDA-ARS?s Scientific Manuscript database

    Nylanderia fulva is an invasive crazy ant that can inundate landscapes and structures. This invasive ant has been called the Caribbean crazy ant in Florida and the Rasberry [sic] crazy ant in Texas. The species was thought to be Nylanderia pubens or Nylanderia near pubens, in Florida and Texas, resp...

  2. The Effect of Diet and Opponent Size on Aggressive Interactions Involving Caribbean Crazy Ants (Nylanderia fulva)

    PubMed Central

    Horn, Katherine C.; Eubanks, Micky D.; Siemann, Evan

    2013-01-01

    Biotic interactions are often important in the establishment and spread of invasive species. In particular, competition between introduced and native species can strongly influence the distribution and spread of exotic species and in some cases competition among introduced species can be important. The Caribbean crazy ant, Nylanderia fulva, was recently introduced to the Gulf Coast of Texas, and appears to be spreading inland. It has been hypothesized that competition with the red imported fire ant, Solenopsis invicta, may be an important factor in the spread of crazy ants. We investigated the potential of interspecific competition among these two introduced ants by measuring interspecific aggression between Caribbean crazy ant workers and workers of Solenopsis invicta. Specifically, we examined the effect of body size and diet on individual-level aggressive interactions among crazy ant workers and fire ants. We found that differences in diet did not alter interactions between crazy ant workers from different nests, but carbohydrate level did play an important role in antagonistic interactions with fire ants: crazy ants on low sugar diets were more aggressive and less likely to be killed in aggressive encounters with fire ants. We found that large fire ants engaged in fewer fights with crazy ants than small fire ants, but fire ant size affected neither fire ant nor crazy ant mortality. Overall, crazy ants experienced higher mortality than fire ants after aggressive encounters. Our findings suggest that fire ant workers might outcompete crazy ant workers on an individual level, providing some biotic resistance to crazy ant range expansion. However, this resistance may be overcome by crazy ants that have a restricted sugar intake, which may occur when crazy ants are excluded from resources by fire ants. PMID:23776702

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

    PubMed

    Meng, Jia; Lei, Jiaxin; Davitt, Andrew; Holt, Jocelyn R; Huang, Jian; Gold, Roger; Vargo, Edward L; Tarone, Aaron M; Zhu-Salzman, Keyan

    2018-05-22

    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 6 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 days. 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. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  4. Efforts to eradicate yellow crazy ants on Johnston Atoll: Results from Crazy Ant Strike Team IX, December 2014-June 2015

    USGS Publications Warehouse

    Banko, Paul C.; Peck, Robert W.; Donmoyer, Kevin; Kropidlowski, Stephan; Pollock, Amanda

    2015-01-01

    The ecologically destructive yellow crazy ant (YCA; Anoplolepis gracilipes) was first detected on Johnston Atoll in January 2010. Within eight months, the U.S. Fish and Wildlife Service had mobilized its first crazy ant strike team (CAST), a group of biologists dedicated to testing and identifying insecticidal baits to be used to eradicate the ant on the atoll. During December 2014‒May 2015 CAST IX focused on testing hydrogel crystals saturated with sucrose solution (25%) carrying the insecticides thiamethoxam and dinotefuran against YCA. A series of experiments, including artificial nest box trials, and field-based palatability trials and eradication tests on small (500 m2 or 0.05 ha) and large plots (2500 m2 or 0.25 ha), were conducted to test concentrations of thiamethoxam ranging from 0.0005% to 0.01%, and dinotefuran at 0.05%. Additionally, the cat food-based matrix containing dinotefuran (0.05%), the standard bait used to suppress YCA on Johnston since 2011, and textured vegetable protein (TVP) carrying dinotefuran at 0.1% and 0.05% were included in large plot tests. Nest box trials were inconclusive due to a consistent loss of queen and worker ants in control boxes, so they were discontinued. Palatability trials suggested higher dosages of thiamethoxam (0.005 and 0.01%) were less attractive than lower dosages (0.0005 and 0.001%) and controls (sucrose only), but small and large plot experiments failed to identify a thiamethoxam concentration that was consistently effective at killing YCA. In contrast, hydrogel containing dinotefuran was consistently effective, killing >95% of YCA on small and large plots. As expected, the cat food bait effectively reduced YCA abundances, but was slightly less effective than hydrogel containing dinotefuran over time. Three successive, approximately weekly treatments of large plots with hydrogel bait, or other baits followed by hydrogel bait, suggest an increasing overall effectiveness, with no aversion of YCA to the bait

  5. Worker reproduction of the invasive yellow crazy ant Anoplolepis gracilipes.

    PubMed

    Lee, Ching-Chen; Nakao, Hirotaka; Tseng, Shu-Ping; Hsu, Hung-Wei; Lin, Gwo-Li; Tay, Jia-Wei; Billen, Johan; Ito, Fuminori; Lee, Chow-Yang; Lin, Chung-Chi; Yang, Chin-Cheng Scotty

    2017-01-01

    Reproductive division of labor is one of the key features of social insects. Queens are adapted for reproduction while workers are adapted for foraging and colony maintenance. In many species, however, workers retain functional ovaries and can lay unfertilized male eggs or trophic eggs. Here we report for the first time on the occurrence of physogastric workers and apparent worker reproduction in the invasive yellow crazy ant Anoplolepis gracilipes (Fr. Smith). We further examined the reproductive potential and nutritional role of physogastric workers through multidisciplinary approaches including morphological characterization, laboratory manipulation, genetic analysis and behavioral observation. Egg production with two types of eggs, namely reproductive and trophic eggs, by physogastric workers was found. The reproductive egg was confirmed to be haploid and male-destined, suggesting that the workers produced males via arrhenotokous parthenogenesis as no spermatheca was discovered. Detailed observations suggested that larvae were mainly fed with trophic eggs. Along with consumption of trophic eggs by queens and other castes as part of their diet, the vital role of physogastric workers as "trophic specialist" is confirmed. We propose that adaptive advantages derived from worker reproduction for A. gracilipes may include 1) trophic eggs provisioned by physogastric workers likely assist colonies of A. gracilipes in overcoming unfavorable conditions such as paucity of food during critical founding stage; 2) worker-produced males are fertile and thus might offer an inclusive fitness advantage for the doomed orphaned colony.

  6. Evidence of niche shift and global invasion potential of the tawny crazy ant, Nylanderia fulva

    USDA-ARS?s Scientific Manuscript database

    Analysis of an invasive species’ niche shift between native and introduced ranges, along with potential distribution maps, can provide valuable information about its invasive potential. The tawny crazy ant, Nylanderia fulva, is a rapidly emerging and economically important invasive species in the so...

  7. Myrmecomorba nylanderiae gen. et sp. nov., a microsporidian parasite of the Tawny Crazy Ant, Nylanderia fulva

    USDA-ARS?s Scientific Manuscript database

    A new microsporidian genus and species, Myrmecomorba nylanderiae, is described from North American populations of the Tawny Crazy Ant Nylanderia fulva. This new species was found to be heterosporous producing several types of binucleate spores in both larval and adult stages and an abortive octospor...

  8. Toxicity Profiles and Colony Effects of Liquid Baits on Tawny Crazy Ants (plus an update on their U.S. distribution)

    USDA-ARS?s Scientific Manuscript database

    Tawny crazy ants, Nylanderia fulva, is an invasive ant that are known to readily forage on the liquid, carbohydrate rich honeydew produced by hemipterans such as aphids and scales. There is interest in developing liquid ant baits that can eliminate tawny crazy ant colonies. Preliminary and anecdot...

  9. Myrmecomorba nylanderiae gen. et sp. nov., a microsporidian parasite of the tawny crazy ant Nylanderia fulva.

    PubMed

    Plowes, Robert M; Becnel, James J; LeBrun, Edward G; Oi, David H; Valles, Steven M; Jones, Nathan T; Gilbert, Lawrence E

    2015-07-01

    A new microsporidian genus and species, Myrmecomorba nylanderiae, is described from North American populations of the tawny crazy ant, Nylanderia fulva. This new species was found to be heterosporous producing several types of binucleate spores in both larval and adult stages and an abortive octosporoblastic sporogony in adult ants. While microsporidia are widespread arthropod parasites, this description represents only the fifth species described from an ant host. Molecular analysis indicated that this new taxon is phylogenetically closely allied to the microsporidian family Caudosporidae, a group known to parasitize aquatic black fly larvae. We report the presence of 3 spore types (Type 1 DK, Type 2 DK, and octospores) with infections found in all stages of host development and reproductive castes. This report documents the first pathogen infecting N. fulva, an invasive ant of considerable economic and ecological consequence. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Efforts to eradicate yellow crazy ants on Johnston Atoll: Results from crazy ant strike teams X, XI and XII (June 2015–December 2016)

    USGS Publications Warehouse

    Peck, Robert W; Banko, Paul C.; Donmoyer, Kevin; Scheiner, Katrina; Karimi, Rebekah; Kropidlowski, Stefan

    2017-01-01

    Efforts to eradicate invasive yellow crazy ants (Anoplolepis gracilipes; YCA) on Johnston Atoll have been continuous since their discovery in 2010. Through 2014, a variety of commercial and novel formicidal baits were tested against the ant, but none proved capable of eradication. More recently, polyacrylamide crystals (“hydrogel”) saturated with a sucrose solution containing the insecticide dinotefuran has been shown to be effective over large areas when applied against YCA alone or sequentially with a protein-based cat food bait. During June 2015–December 2016, Crazy Ant Strike Teams (CASTs) conducted treatment and monitoring efforts across an infestation of about 57 ha on Johnston Atoll. Following three infestation-wide treatments (primarily using hydrogel) during 2015, YCA were reduced 98% and surviving nests became difficult to find. Subsequently, a protocol designed to detect ants at low abundance that combined hand searching with a high density of baited monitoring stations (12 stations/0.25 ha; HST protocol) was employed within a network of 50 x 50 m cells that subdivided the infestation. During 2016 YCA were found at numerous locations using this method and standard grid-based bait monitoring surveys. Overall, 65 cells where YCA were detected, or cells adjacent to detections, were treated with hydrogel or cat food bait. YCA were not detected during four monitoring events each separated by at least one week, on 85% of these cells after 1–3 treatments, but it was necessary to treat several cells 4–7 times before YCA were eliminated. Results from HST searches allowed us to estimate the probability that YCA were detected when present in an area when searched using that method. Based on this probability, it was determined that areas would have to be searched three times without YCA being detected to allow 93% certainty that the ants were absent. The level of certainty increased to 99% when the search was conducted four times and YCA were not found

  11. North American Invasion of the Tawny Crazy Ant (Nylanderia fulva) Is Enabled by Pheromonal Synergism from Two Separate Glands.

    PubMed

    Zhang, Qing-He; McDonald, Danny L; Hoover, Doreen R; Aldrich, Jeffrey R; Schneidmiller, Rodney G

    2015-09-01

    A new invader, the "tawny crazy ant", Nylanderia fulva (Hymenoptera: Formicidae; Formicinae), is displacing the red imported fire ant, Solenopsis invicta (Formicidae: Myrmicinae), in the southern U.S., likely through its superior chemical arsenal and communication. Alone, formic acid is unattractive, but this venom (= poison) acid powerfully synergizes attraction of tawny crazy ants to volatiles from the Dufour's gland secretion of N. fulva workers, including the two major components, undecane and 2-tridecanone. The unexpected pheromonal synergism between the Dufour's gland and the venom gland appears to be another key factor, in addition to previously known defensive and detoxification semiochemical features, for the successful invasion and domination of N. fulva in the southern U.S. This synergism is an efficient mechanism enabling N. fulva workers to outcompete Solenopsis and other ant species for food and territory. From a practical standpoint, judicious point-source release formulation of tawny crazy ant volatiles may be pivotal for enhanced attract-and-kill management of this pest.

  12. Targeted research to improve invasive species management: yellow crazy ant Anoplolepis gracilipes in Samoa.

    PubMed

    Hoffmann, Benjamin D; Auina, Saronna; Stanley, Margaret C

    2014-01-01

    Lack of biological knowledge of invasive species is recognised as a major factor contributing to eradication failure. Management needs to be informed by a site-specific understanding of the invasion system. Here, we describe targeted research designed to inform the potential eradication of the invasive yellow crazy ant Anoplolepis gracilipes on Nu'utele island, Samoa. First, we assessed the ant's impacts on invertebrate biodiversity by comparing invertebrate communities between infested and uninfested sites. Second, we investigated the timing of production of sexuals and seasonal variation of worker abundance and nest density. Third, we investigated whether an association existed between A. gracilipes and carbohydrate sources. Within the infested area there were few other ants larger than A. gracilipes, as well as fewer spiders and crabs, indicating that A. gracilipes is indeed a significant conservation concern. The timing of male reproduction appears to be consistent with places elsewhere in the world, but queen reproduction was outside of the known reproductive period for this species in the region, indicating that the timing of treatment regimes used elsewhere are not appropriate for Samoa. Worker abundance and nest density were among the highest recorded in the world, being greater in May than in October. These abundance and nest density data form baselines for quantifying treatment efficacy and set sampling densities for post-treatment assessments. The number of plants and insects capable of providing a carbohydrate supply to ants were greatest where A. gracilipes was present, but it is not clear if this association is causal. Regardless, indirectly controlling ant abundance by controlling carbohydrate supply appears to be promising avenue for research. The type of targeted, site-specific research such as that described here should be an integral part of any eradication program for invasive species to design knowledge-based treatment protocols and determine

  13. A Review of the Tawny Crazy Ant, Nylanderia fulva, an Emergent Ant Invader in the Southern United States: Is Biological Control a Feasible Management Option?

    PubMed Central

    Wang, Zinan; Moshman, Lori; Kraus, Emily C.; Wilson, Blake E.; Acharya, Namoona; Diaz, Rodrigo

    2016-01-01

    The tawny crazy ant, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae), has invaded states of the U.S. including Texas, Louisiana, Mississippi, Alabama, Florida, and Georgia. Native to South America, N. fulva is considered a pest in the U.S. capable of annoying homeowners and farmers, as well as displacing native ant species. As it continues to expand its range, there is a growing need to develop novel management techniques to control the pest and prevent further spread. Current management efforts rely heavily on chemical control, but these methods have not been successful. A review of the biology, taxonomy, ecology, and distribution of N. fulva, including discussion of ecological and economic consequences of this invasive species, is presented. Options for future management are suggested focusing on biological control, including parasitoid flies in the genus Pseudacteon, the microsporidian parasite Myrmecomorba nylanderiae, and a novel polynucleotide virus as potential biological control agents. We suggest further investigation of natural enemies present in the adventive range, as well as foreign exploration undertaken in the native range including Paraguay, Brazil, and Argentina. We conclude that N. fulva may be a suitable candidate for biological control. PMID:27983690

  14. A Review of the Tawny Crazy Ant, Nylanderia fulva, an Emergent Ant Invader in the Southern United States: Is Biological Control a Feasible Management Option?

    PubMed

    Wang, Zinan; Moshman, Lori; Kraus, Emily C; Wilson, Blake E; Acharya, Namoona; Diaz, Rodrigo

    2016-12-15

    The tawny crazy ant, Nylanderia fulva (Mayr) (Hymenoptera: Formicidae), has invaded states of the U.S. including Texas, Louisiana, Mississippi, Alabama, Florida, and Georgia. Native to South America, N. fulva is considered a pest in the U.S. capable of annoying homeowners and farmers, as well as displacing native ant species. As it continues to expand its range, there is a growing need to develop novel management techniques to control the pest and prevent further spread. Current management efforts rely heavily on chemical control, but these methods have not been successful. A review of the biology, taxonomy, ecology, and distribution of N. fulva , including discussion of ecological and economic consequences of this invasive species, is presented. Options for future management are suggested focusing on biological control, including parasitoid flies in the genus Pseudacteon , the microsporidian parasite Myrmecomorba nylanderiae , and a novel polynucleotide virus as potential biological control agents. We suggest further investigation of natural enemies present in the adventive range, as well as foreign exploration undertaken in the native range including Paraguay, Brazil, and Argentina. We conclude that N. fulva may be a suitable candidate for biological control.

  15. Defensive chemicals of tawny crazy ants, Nylanderia fulva and their toxicity to red imported fire ants (Hymenoptera: Formicidae)

    USDA-ARS?s Scientific Manuscript database

    Nylanderia fulva (Mayr) has been reported as being able to displace Solenopsis invicta Buren, one of the most aggressive invasive ants in the world. Like S. invicta, N. fulva use chemical secretions in their defense/offense, which may contribute to their observed superior competition ability. In t...

  16. Metatranscriptomics and Pyrosequencing Facilitate Discovery of Potential Viral Natural Enemies of the Invasive Caribbean Crazy Ant, Nylanderia pubens

    PubMed Central

    Valles, Steven M.; Oi, David H.; Yu, Fahong; Tan, Xin-Xing; Buss, Eileen A.

    2012-01-01

    Background Nylanderia pubens (Forel) is an invasive ant species that in recent years has developed into a serious nuisance problem in the Caribbean and United States. A rapidly expanding range, explosive localized population growth, and control difficulties have elevated this ant to pest status. Professional entomologists and the pest control industry in the United States are urgently trying to understand its biology and develop effective control methods. Currently, no known biological-based control agents are available for use in controlling N. pubens. Methodology and Principal Findings Metagenomics and pyrosequencing techniques were employed to examine the transcriptome of field-collected N. pubens colonies in an effort to identify virus infections with potential to serve as control agents against this pest ant. Pyrosequencing (454-platform) of a non-normalized N. pubens expression library generated 1,306,177 raw sequence reads comprising 450 Mbp. Assembly resulted in generation of 59,017 non-redundant sequences, including 27,348 contigs and 31,669 singlets. BLAST analysis of these non-redundant sequences identified 51 of potential viral origin. Additional analyses winnowed this list of potential viruses to three that appear to replicate in N. pubens. Conclusions Pyrosequencing the transcriptome of field-collected samples of N. pubens has identified at least three sequences that are likely of viral origin and, in which, N. pubens serves as host. In addition, the N. pubens transcriptome provides a genetic resource for the scientific community which is especially important at this early stage of developing a knowledgebase for this new pest. PMID:22384082

  17. Societies drifting apart? Behavioural, genetic and chemical differentiation between supercolonies in the yellow crazy ant Anoplolepis gracilipes.

    PubMed

    Drescher, Jochen; Blüthgen, Nico; Schmitt, Thomas; Bühler, Jana; Feldhaar, Heike

    2010-10-22

    In populations of most social insects, gene flow is maintained through mating between reproductive individuals from different colonies in periodic nuptial flights followed by dispersal of the fertilized foundresses. Some ant species, however, form large polygynous supercolonies, in which mating takes place within the maternal nest (intranidal mating) and fertilized queens disperse within or along the boundary of the supercolony, leading to supercolony growth (colony budding). As a consequence, gene flow is largely confined within supercolonies. Over time, such supercolonies may diverge genetically and, thus, also in recognition cues (cuticular hydrocarbons, CHC's) by a combination of genetic drift and accumulation of colony-specific, neutral mutations. We tested this hypothesis for six supercolonies of the invasive ant Anoplolepis gracilipes in north-east Borneo. Within supercolonies, workers from different nests tolerated each other, were closely related and showed highly similar CHC profiles. Between supercolonies, aggression ranged from tolerance to mortal encounters and was negatively correlated with relatedness and CHC profile similarity. Supercolonies were genetically and chemically distinct, with mutually aggressive supercolony pairs sharing only 33.1%±17.5% (mean ± SD) of their alleles across six microsatellite loci and 73.8%±11.6% of the compounds in their CHC profile. Moreover, the proportion of alleles that differed between supercolony pairs was positively correlated to the proportion of qualitatively different CHC compounds. These qualitatively differing CHC compounds were found across various substance classes including alkanes, alkenes and mono-, di- and trimethyl-branched alkanes. We conclude that positive feedback between genetic, chemical and behavioural traits may further enhance supercolony differentiation through genetic drift and neutral evolution, and may drive colonies towards different evolutionary pathways, possibly including speciation.

  18. Integrating biology into invasive species management is a key principle for eradication success: the case of yellow crazy ant Anoplolepis gracilipes in northern Australia.

    PubMed

    Hoffmann, B D

    2015-04-01

    The lack of biological knowledge of many invasive species remains as one of the greatest impediments to their management. Here I detail targeted research into the biology of the yellow crazy ant Anoplolepis gracilipes within northern Australia and detail how such knowledge can be used to improve the management outcomes for this species. I quantified nest location and density in three habitats, worker activity over 24 h, infestation expansion rate, seasonal variation of worker abundance and the timing of production of sexuals. Nests were predominantly (up to 68%) located at the bases of large trees, indicating that search efforts should focus around tree bases. Nest density was one nest per 22, 7.1 and 6.3 m2 in the three habitats, respectively. These data form the baselines for quantifying treatment efficacy and set sampling densities for post-treatment assessments. Most (60%) nests were underground, predominantly (89%) occurring in an open area rather than underneath a rock or log. Some seasonality was evident for nests within leaf litter, with most (83%) occurring during the 'wet season' (October-March). Of the underground nests, most were shallow, with 44% being less than 10 cm deep, and 67% being less than 20 cm deep. Such nest location and density information serves many management purposes, for improving detection, mapping and post-treatment assessments, and also provided strong evidence that carbohydrate supply was a major driver of A. gracilipes populations. Just over half of the nests (56%) contained queens. Of the 62 underground nests containing queens, most queens (80%) were located at the deepest chamber. When queens were present, most often (38%) only one queen was present, the most being 16. Queen number per nest was the lowest in July and August just prior to the emergence of virgin queens in September, with queen numbers then remaining steadily high until April. Nothing is known for any ant species about how the queen number per nest/colony affects

  19. Crazy Patchwork Clay Bowl

    ERIC Educational Resources Information Center

    Hobbs, Janice

    2007-01-01

    Crazy patchwork quilts, which inspired this bowl, are as American as apple pie. In 1876, the Philadelphia Centennial Exposition opened and the American society fell instantly in love with Japanese ceramics and asymmetrical art. Victorian ladies incorporated the idea of asymmetrical design into their quilts, which became known as crazy quilts. The…

  20. Isolation and characterization of Nylanderia fulva virus 1, a positive-sense, single-stranded RNA virus infecting the tawny crazy ant, Nylanderia fulva

    SciTech Connect

    Valles, Steven M., E-mail: steven.valles@ars.usda.gov; Oi, David H.; Becnel, James J.

    We report the discovery of Nylanderia fulva virus 1 (NfV-1), the first virus identified and characterized from the ant, Nylanderia fulva. The NfV-1 genome (GenBank accession KX024775) is 10,881 nucleotides in length, encoding one large open reading frame (ORF). Helicase, protease, RNA-dependent RNA polymerase, and jelly-roll capsid protein domains were recognized within the polyprotein. Phylogenetic analysis placed NfV-1 in an unclassified clade of viruses. Electron microscopic examination of negatively stained samples revealed particles with icosahedral symmetry with a diameter of 28.7±1.1 nm. The virus was detected by RT-PCR in larval, pupal, worker and queen developmental stages. However, the replicative strandmore » of NfV-1 was only detected in larvae. Vertical transmission did not appear to occur, but horizontal transmission was facile. The inter-colonial field prevalence of NfV-1 was 52±35% with some local infections reaching 100%. NfV-1 was not detected in limited samples of other Nylanderia species or closely related ant species. - Highlights: • A new positive-strand RNA virus was discovered in the ant, Nylanderia fulva. • The Nylanderia fulva virus 1 genome was comprised of 10,881 nucleotides. • NfV-1 was detected in larval, pupal, queen and worker ants, but not eggs. • Replication of NfV-1 appeared to be limited to the larval stage.« less

  1. Who's Crazy? Students Critique "The Gods Must Be Crazy"

    ERIC Educational Resources Information Center

    Hawking, Chris

    2012-01-01

    On the surface, "The Gods Must Be Crazy" is a campy confluence of three independent plotlines involving Xi, a Kalahari tribesman, who journeys to the end of the earth to dispose of a Coke bottle that has begun to disrupt the harmony of his community; Mr. Steyn, a white scientist, and the beautiful blonde schoolteacher he escorts through the bush;…

  2. Crazy Engineering Starshade and Coronagraph

    NASA Image and Video Library

    2016-04-26

    Episode 7 of Crazy Engineering series. Host Mike Meacham, Mechanical Engineer at JPL, learns about the two technologies NASA is investing in to image exoplanets: the Starshade and the Coronagraph. Mike interviews Nick Siegler, Program Chief Technologist, NASA Exoplanet Program in the Starshade lab and the High Contrast Imaging Testbed lab.

  3. Whose crazy investment in sex?

    PubMed

    Mandlis, Lane R

    2011-01-01

    By probing the processes of exclusion of transsexuals from the political sphere, this article offers contributions to social and political theory through an examination of the processes of exclusion from the category "human." This article considers how the erasure of investment in their own embodied sex constructs a platform from which to blame others for sex/gender variance, as well as to justify that blaming. Bringing together Giorgio Agamben, Georges Bataille, Judith Butler, and Nikolas Rose with transphobia, medicalization in psychiatry, law, and ethopolitics, this article questions whose investment in sexed embodiment counts and why that investment might be seen as "crazy."

  4. cDNAs from Nylanderia sp nr pubens (Hymenoptera: Formicidae)

    USDA-ARS?s Scientific Manuscript database

    7 new gene sequences were identified from workers of Rasberry crazy ant, Nylanderia sp.nr. pubens, and submitted to the National Center for Biotechnology Information GenBank. GenBank accession numbers are HQ636472-HQ636478. This information will provide scientists with genetic tools to study the pop...

  5. Complete cDNAs from Nylanderia sp. nr. pubens (Hymenoptera: Formicidae). GenBank GU980916-GU980928.

    USDA-ARS?s Scientific Manuscript database

    13 new gene sequences were identified from workers of Rasberry crazy ant, Nylanderia sp.nr. pubens, and submitted to the National Center for Biotechnology Information GenBank. GenBank accession numbers are GU980916-GU980928. This information will provide scientists with genetic tools to study the p...

  6. Crazy-Proofing High School Sports

    ERIC Educational Resources Information Center

    Tufte, John E.

    2012-01-01

    "Crazy-Proofing High School Sports" examines the often troubling high school sports phenomenon in two parts. Part one focuses on the problems facing educators, students, and parents as they struggle to make high school sports worthwhile. Few if any strategies for improvement in education are effective without first knowing what the real reasons…

  7. Crazy Horse, The Story of an American Indian.

    ERIC Educational Resources Information Center

    Milton, John R.

    A great monument is being blasted out of Thunderhead Mountain near Mount Rushmore in South Dakota. Slowly, Chief Crazy Horse emerges from the stone. One day he will sit on his Indian pony pointing over the Black Hills as though saying, "My lands are where my dead lie buried." This biography of Crazy Horse begins with sculptor Korczak…

  8. CrazyEgg Reports for Single Page Analysis

    EPA Pesticide Factsheets

    CrazyEgg provides an in depth look at visitor behavior on one page. While you can use GA to do trend analysis of your web area, CrazyEgg helps diagnose the design of a single Web page by visually displaying all visitor clicks during a specified time.

  9. First record of the ant cricket Myrmecophilus (Myrmecophilina) americanus (Orthoptera: Myrmecophilidae) in Mexico.

    PubMed

    Ortega-Morales, Aldo I; Rodríguez, Quetzaly K Siller; Garza-Hernández, Javier A; Adeniran, Adebiyi A; Hernández-Triana, Luis M; Rodríguez-Pérez, Mario A

    2017-04-27

    In September 2004, the New World ant cricket, Myrmecophilus americanus Saussure, 1877, was collected in association with longhorn crazy ants, Paratrechina longicornis (Latreille. 1802), in the state of Coahuila, Mexico. We are reporting the DNA barcode using the mitochrondrial cytochrome oxidase subunit I for this first record of M. americanus in Mexico.

  10. Do stock prices drive people crazy?

    PubMed

    Lin, Chung-Liang; Chen, Chin-Shyan; Liu, Tsai-Ching

    2015-03-01

    This is the first research to examine a potential relation between stock market volatility and mental disorders. Using data on daily incidences of mental disorders in Taiwan over 4000 days from 1998 through 2009 to assess the time-series relation between stock price movements and mental disorders, we observe that stock price fluctuation clearly affects the hospitalization of mental disorders. We find that during a 12-year follow-up period, a low stock price index, a daily fall in the stock price index and consecutive daily falls in the stock price index are all associated with greater of mental disorders hospitalizations. A 1000-point fall in the TAIEX (Taiwan Stock Exchange Capitalization Weighted Stock Index) increases the number of daily mental disorders hospitalizations by 4.71%. A 1% fall in the TAIEX in one single day increases daily hospitalizations for mental disorders by 0.36%. When the stock price index falls one consecutive day, it causes a daily increase of approximately 0.32% hospitalizations due to mental disorders on that day. Stock price index is found to be significant for both gender and all age groups. In addition, daily change is significant for both gender and middle-age groups, whereas accumulated change is significant for males and people aged 45-64. Stockholdings can help people accumulate wealth, but they can also increase mental disorders hospitalizations. In other words, stock price fluctuations do drive people crazy. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine © The Author 2014; all rights reserved.

  11. The crazy hollow formation (Eocene) of central Utah

    USGS Publications Warehouse

    Weiss, M.P.; Warner, K.N.

    2001-01-01

    The Late Eocene Crazy Hollow Formation is a fluviatile and lacustrine unit that was deposited locally in the southwest arm of Lake Uinta during and after the last stages of the lake the deposited the Green River Formation. Most exposures of the Crazy Hollow are located in Sanpete and Sevier Counties. The unit is characterized by a large variety of rock types, rapid facies changes within fairly short distances, and different lithofacies in the several areas where outcrops of the remnants of the formation are concentrated. Mudstone is dominant, volumetrically, but siltstone, shale, sandstone, conglomerate and several varieties of limestone are also present. The fine-grained rocks are mostly highly colored, especially in shades of yellow, orange and red. Sand grains, pebbles and small cobbles of well-rounded black chert are widespread, and "salt-and-pepper sandstone" is the conspicuous characteristic of the Crazy Hollow. The salt-and-pepper sandstone consists of grains of black chert, white chert, quartz and minor feldspar. The limestone beds and lenses are paludal and lacustrine in origin; some are fossiliferous, and contain the same fauna found in the Green River Formation. With trivial exceptions, the Crazy Hollow Formation lies on the upper, limestone member of the Green River Formation, and the beds of the two units are always accordant in attitude. The nature of the contact differs locally: at some sites there is gradation from the Green River to the Crazy Hollow; at others, rocks typical of the two units intertongue; elsewhere there is a disconformity between the two. A variety of bedrock units overlie the Crazy Hollow at different sites. In the southeasternmost districts it is overlain by the late Eocene formation of Aurora; in western Sevier County it is overlain by the Miocene-Pliocene Sevier River Formation; in northernmost Sanpete County it is overlain by the Oligocene volcanics of the Moroni Formation. At many sites bordering Sanpete and Sevier Valleys

  12. Honey Ants.

    ERIC Educational Resources Information Center

    Conway, John R.

    1984-01-01

    Provides background information on honey ants. These ants are found in dry or desert regions of North America, Africa, and Australia. Also provides a list of activities using local species of ants. (JN)

  13. Fire ants

    MedlinePlus

    ... a fire ant delivers a harmful substance, called venom, into your skin. This article is for information ... in the United States. Poisonous Ingredient Fire ant venom contains a chemical called piperidine. Where Found Fire ...

  14. Stinging ants.

    PubMed

    Rhoades, R

    2001-08-01

    Ants belong to the order Hymenoptera, along with bees, wasps, yellow jackets, etc., they are the most successful animal genera in this world. It is their selfless social structure which accounts for their huge impact. Their effect on man ranges from the parasol ant, which makes plant cultivation untenable in certain parts of South America, to Solenopsis Invicta in the southeastern United States of America, which kill ground dwelling birds and small animals, harass livestock, and renders farmland unusable. With the exception of the Bulldog Ant of Australia (which is the size of a medium cockroach) direct toxic effects are not a lethal threat to man. Human fatalities and morbidity are related to secondary infections of excoriated stings or allergic anaphylaxis. This article reviews history and recent developments regarding stinging ants around the world.

  15. Spatial Analysis of “Crazy Quilts”, a Class of Potentially Random Aesthetic Artefacts

    PubMed Central

    Westphal-Fitch, Gesche; Fitch, W. Tecumseh

    2013-01-01

    Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. “Crazy quilts” represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures. PMID:24066095

  16. Spatial analysis of "crazy quilts", a class of potentially random aesthetic artefacts.

    PubMed

    Westphal-Fitch, Gesche; Fitch, W Tecumseh

    2013-01-01

    Human artefacts in general are highly structured and often display ordering principles such as translational, reflectional or rotational symmetry. In contrast, human artefacts that are intended to appear random and non symmetrical are very rare. Furthermore, many studies show that humans find it extremely difficult to recognize or reproduce truly random patterns or sequences. Here, we attempt to model two-dimensional decorative spatial patterns produced by humans that show no obvious order. "Crazy quilts" represent a historically important style of quilt making that became popular in the 1870s, and lasted about 50 years. Crazy quilts are unusual because unlike most human artefacts, they are specifically intended to appear haphazard and unstructured. We evaluate the degree to which this intention was achieved by using statistical techniques of spatial point pattern analysis to compare crazy quilts with regular quilts from the same region and era and to evaluate the fit of various random distributions to these two quilt classes. We found that the two quilt categories exhibit fundamentally different spatial characteristics: The patch areas of crazy quilts derive from a continuous random distribution, while area distributions of regular quilts consist of Gaussian mixtures. These Gaussian mixtures derive from regular pattern motifs that are repeated and we suggest that such a mixture is a distinctive signature of human-made visual patterns. In contrast, the distribution found in crazy quilts is shared with many other naturally occurring spatial patterns. Centroids of patches in the two quilt classes are spaced differently and in general, crazy quilts but not regular quilts are well-fitted by a random Strauss process. These results indicate that, within the constraints of the quilt format, Victorian quilters indeed achieved their goal of generating random structures.

  17. Ant nebula

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A new Hubble Space Telescope image of a celestial object called the Ant Nebula may shed new light on the future demise of our Sun. The image is available at http://www.jpl.nasa.gov/pictures/wfpc .

    The nebula, imaged on July 20, 1997, and June 30, 1998, by Hubble's Wide Field and Planetary Camera 2, was observed by Drs. Raghvendra Sahai and John Trauger of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Bruce Balick of the University of Washington in Seattle; and Vincent Icke of Leiden University in the Netherlands. JPL designed and built the camera.

    The Ant Nebula, whose technical name is Mz3, resembles the head and thorax of an ant when observed with ground-based telescopes. The new Hubble image, with 10 times the resolution revealing 100 times more detail, shows the 'ant's' body as a pair of fiery lobes protruding from a dying, Sun- like star. The Ant Nebula is located between 3,000 and 6,000 light years from Earth in the southern constellation Norma.

    The image challenges old ideas about what happens to dying stars. This observation, along with other pictures of various remnants of dying stars called planetary nebulae, shows that our Sun's fate will probably be much more interesting, complex and dramatic than astronomers previously believed.

    Although the ejection of gas from the dying star in the Ant Nebula is violent, it does not show the chaos one might expect from an ordinary explosion, but instead shows symmetrical patterns. One possibility is that the central star has a closely orbiting companion whose gravitational tidal forces shape the outflowing gas. A second possibility is that as the dying star spins, its strong magnetic fields are wound up into complex shapes like spaghetti in an eggbeater. Electrically charged winds, much like those in our Sun's solar wind but millions of times denser and moving at speeds up to 1,000 kilometers per second (more than 600 miles per second) from the star, follow the twisted field lines on their way

  18. The Ants Have It!

    ERIC Educational Resources Information Center

    Daugherty, Belinda

    2001-01-01

    Uses the GEMS guide, "Ants at Home Underground", to explore the life of ants and teach about them in a classroom setting. The activity applies students' knowledge of ants and students learn about ant colonies, what ants eat, and how they live. (SAH)

  19. Application of artifical intelligence principles to the analysis of "crazy" speech.

    PubMed

    Garfield, D A; Rapp, C

    1994-04-01

    Artificial intelligence computer simulation methods can be used to investigate psychotic or "crazy" speech. Here, symbolic reasoning algorithms establish semantic networks that schematize speech. These semantic networks consist of two main structures: case frames and object taxonomies. Node-based reasoning rules apply to object taxonomies and pathway-based reasoning rules apply to case frames. Normal listeners may recognize speech as "crazy talk" based on violations of node- and pathway-based reasoning rules. In this article, three separate segments of schizophrenic speech illustrate violations of these rules. This artificial intelligence approach is compared and contrasted with other neurolinguistic approaches and is discussed as a conceptual link between neurobiological and psychodynamic understandings of psychopathology.

  20. Geochemical and petrographic data for intrusions peripheral to the Big Timber Stock, Crazy Mountains, Montana

    USGS Publications Warehouse

    du Bray, Edward A.; Van Gosen, Bradley S.

    2015-01-01

    The Paleocene Fort Union Formation hosts a compositionally diverse array of Eocene plugs, dikes, and sills arrayed around the Eocene Big Timber stock in the Crazy Mountains of south-central Montana. The geochemistry and petrography of the sills have not previously been characterized or interpreted. The purpose of this report is (1) to present available geochemical and petrographic data for several dozen samples of these rocks and (2) to provide a basic interpretive synthesis of these data.

  1. Fire Ant Bites

    MedlinePlus

    ... Favorite Name: Category: Share: Yes No, Keep Private Fire Ant Bites Share | Fire ants are aggressive, venomous insects that have pinching ... across the United States, even into Puerto Rico. Fire ant stings usually occur on the feet or ...

  2. Imported fire ants: the ants from hell!

    PubMed

    Freeman, T M

    1994-01-01

    Imported fire ants may certainly be considered the ANTS FROM HELL! This review focuses on both the interesting entomology of fire ants and the important medical characteristics of fire ant stings. They sting and they kill; they destroy; they mate in mid-air; and we may not be able to stop them. However, although they inject extremely potent venom, individuals can prevent secondary infections by leaving the so-called pustules alone and not opening them. Individuals who suffer systemic reactions may receive adequate treatment with the whole body extract immunotherapy.

  3. "Crazy? So what!": A School Programme to Promote Mental Health and Reduce Stigma--Results of a Pilot Study

    ERIC Educational Resources Information Center

    Conrad, Ines; Dietrich, Sandra; Heider, Dirk; Blume, Anne; Angermeyer, Matthias C.; Riedel-Heller, Steffi

    2009-01-01

    Purpose: The purpose of this paper is to evaluate the health-promoting and stigma-reducing effect of the German school-based programme "Crazy? So what!". Design/methodology/approach: A quasi-experimental longitudinal control-study was carried out with assessments one week prior to the school programme, immediately after it and three…

  4. Ant- and Ant-Colony-Inspired ALife Visual Art.

    PubMed

    Greenfield, Gary; Machado, Penousal

    2015-01-01

    Ant- and ant-colony-inspired ALife art is characterized by the artistic exploration of the emerging collective behavior of computational agents, developed using ants as a metaphor. We present a chronology that documents the emergence and history of such visual art, contextualize ant- and ant-colony-inspired art within generative art practices, and consider how it relates to other ALife art. We survey many of the algorithms that artists have used in this genre, address some of their aims, and explore the relationships between ant- and ant-colony-inspired art and research on ant and ant colony behavior.

  5. Ants in Space

    NASA Image and Video Library

    2014-01-13

    ISS038-E-029106 (12 Jan. 2014) --- The Ant Forage Habitat Facility is featured in this image photographed by an Expedition 38 crew member on the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

  6. Ants in Space

    NASA Image and Video Library

    2014-01-13

    ISS038-E-029133 (12 Jan. 2014) --- The Ant Forage Habitat Facility is featured in this image photographed by an Expedition 38 crew member on the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

  7. Ants in Space

    NASA Image and Video Library

    2014-01-14

    ISS038-E-029161 (12 Jan. 2014) --- The Ant Forage Habitat Facility is featured in this image photographed by an Expedition 38 crew member on the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

  8. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029062 (12 Jan. 2014) --- In the International Space Station's Destiny laboratory, NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  9. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029077 (12 Jan. 2014) --- In the International Space Station's Harmony node, NASA astronaut Mike Hopkins, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  10. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029065 (12 Jan. 2014) --- In the International Space Station's Destiny laboratory, NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  11. Ants in Space

    NASA Image and Video Library

    2014-01-12

    ISS038-E-029059 (12 Jan. 2014) --- In the International Space Station's Destiny laboratory, NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, uses a video camera to photograph the Ant Forage Habitat Facility which will study ant behavior and colonization in microgravity.

  12. Television's "crazy lady" trope: female psychopathic traits, teaching, and influence of popular culture.

    PubMed

    Cerny, Cathleen; Friedman, Susan Hatters; Smith, Delaney

    2014-04-01

    This article describes notable illustrations of female psychopathy on modern television to review various characters that will have utility in teaching students about female psychopathy in distinction to male psychopathy and to encourage consideration of the potential effects that viewing these countless examples may have on a generation of young women. The authors use examples from soap operas, crime procedurals, reality television, fantasy, comedies, and young adult programs to illustrate gender differences in psychopathy and make specific teaching points. They also review the research literature related to popular culture's impact on behavior and gender roles. Gender differences in real-world psychopathy are mirrored in television portrayals. For example, female psychopaths, on TV and in reality, use sexual manipulation, demonstrate unstable emotions, and employ social aggression to achieve their ambitions. The examples of female psychopathic traits are prevalent on TV and easily accessible for teaching purposes. Research does give some support for a popular culture impact on behavior and gender roles. As compared to male psychopathy, female psychopathy is less recognized, and there are some notable differences in how the psychopathic traits manifest. Television provides myriad teaching examples that can highlight the gender distinctions such as use of sexual manipulation, emotional instability, and social aggression. Research suggests that the prevalence of "crazy ladies" on television may be negatively impacting gender stereotypes and normalizing bad behavior in young women.

  13. Helicobacter pylori eradication and reflux disease onset: did gastric acid get "crazy"?

    PubMed

    Zullo, Angelo; Hassan, Cesare; Repici, Alessandro; Bruzzese, Vincenzo

    2013-02-14

    Gastroesophageal reflux disease (GORD) is highly prevalent in the general population. In the last decade, a potential relationship between Helicobacter pylori (H. pylori) eradication and GORD onset has been claimed. The main putative mechanism is the gastric acid hypersecretion that develops after bacterial cure in those patients with corpus-predominant gastritis. We performed a critical reappraisal of the intricate pathogenesis and clinical data available in this field. Oesophagitis onset after H. pylori eradication in duodenal ulcer patients has been ascribed to a gastric acid hypersecretion, which could develop following body gastritis healing. However, the absence of an acid hypersecretive status in these patients is documented by both pathophysiology and clinical studies. Indeed, duodenal ulcer recurrence is virtually abolished following H. pylori eradication. In addition, intra-oesophageal pH recording studies failed to demonstrated increased acid reflux following bacterial eradication. Moreover, oesophageal manometric studies suggest that H. pylori eradication would reduce--rather than favor--acid reflux into the oesophagus. Finally, data of clinical studies would suggest that H. pylori eradication is not significantly associated with either reflux symptoms or erosive oesophagitis onset, some data suggesting also an advantage in curing the infection when oesophagitis is already present. Therefore, the legend of "crazy acid" remains--as all the others--a fascinating, but imaginary tale.

  14. A method for velocity signal reconstruction of AFDISAR/PDV based on crazy-climber algorithm

    NASA Astrophysics Data System (ADS)

    Peng, Ying-cheng; Guo, Xian; Xing, Yuan-ding; Chen, Rong; Li, Yan-jie; Bai, Ting

    2017-10-01

    The resolution of Continuous wavelet transformation (CWT) is different when the frequency is different. For this property, the time-frequency signal of coherent signal obtained by All Fiber Displacement Interferometer System for Any Reflector (AFDISAR) is extracted. Crazy-climber Algorithm is adopted to extract wavelet ridge while Velocity history curve of the measuring object is obtained. Numerical simulation is carried out. The reconstruction signal is completely consistent with the original signal, which verifies the accuracy of the algorithm. Vibration of loudspeaker and free end of Hopkinson incident bar under impact loading are measured by AFDISAR, and the measured coherent signals are processed. Velocity signals of loudspeaker and free end of Hopkinson incident bar are reconstructed respectively. Comparing with the theoretical calculation, the particle vibration arrival time difference error of the free end of Hopkinson incident bar is 2μs. It is indicated from the results that the algorithm is of high accuracy, and is of high adaptability to signals of different time-frequency feature. The algorithm overcomes the limitation of modulating the time window artificially according to the signal variation when adopting STFT, and is suitable for extracting signal measured by AFDISAR.

  15. Ants and ant scent reduce bumblebee pollination of artificial flowers.

    PubMed

    Cembrowski, Adam R; Tan, Marcus G; Thomson, James D; Frederickson, Megan E

    2014-01-01

    Ants on flowers can disrupt pollination by consuming rewards or harassing pollinators, but it is difficult to disentangle the effects of these exploitative and interference forms of competition on pollinator behavior. Using highly rewarding and quickly replenishing artificial flowers that simulate male or female function, we allowed bumblebees (Bombus impatiens) to forage (1) on flowers with or without ants (Myrmica rubra) and (2) on flowers with or without ant scent cues. Bumblebees transferred significantly more pollen analogue both to and from ant-free flowers, demonstrating that interference competition with ants is sufficient to modify pollinator foraging behavior. Bees also removed significantly less pollen analogue from ant-scented flowers than from controls, making this the first study to show that bees can use ant scent to avoid harassment at flowers. Ant effects on pollinator behavior, possibly in addition to their effects on pollen viability, may contribute to the evolution of floral traits minimizing ant visitation.

  16. 40Ar/39Ar dates from alkaline intrusions of the northern Crazy Mountains, south-central Montana

    NASA Astrophysics Data System (ADS)

    Harlan, S. S.

    2005-05-01

    The Crazy Mountains basin of south-central Montana is a complex foreland basin that formed during the interaction of thin-skinned, decollement-style folds of the Montana thrust belt and the basement-involved folds and thrust faults of the Rocky Mountain foreland province. Near the depositional center of the basin, synorogenic strata of the Paleocene Fort Union Formation have been intruded and locally thermally metamorphosed by strongly alkaline to subalkaline Tertiary intrusive rocks. The subalkaline rocks are found mostly in the southern Crazy Mountains and form stocks (Big Timber stock, Loco Mountain stock), radiating dikes and sills. With the exception of the Ibex Mountain sill (?), the alkaline rocks are restricted to the northern Crazy Mountains. New 40Ar/39Ar dates are reported from the strongly alkaline rocks, including the Comb Creek stock and dike swarm, the Ibex Mountain sill(?), and sills from the Robinson anticline intrusive complex. The alkaline rocks of the Robinson anticline intrusive complex are exposed in the easternmost folds of the Cordilleran fold and thrust belt, but despite their arcuate and apparently folded map geometry they have been shown to post-date folding. Hornblende from a trachyte sill in the Robinson anticline intrusive complex yielded a relatively simple age spectrum with a weighted mean of 50.61 ± 0.14 Ma (2σ), which probably records the age of sill emplacement. Nepheline syenite and mafic nepheline syenites of the Comb Creek stock and a dike from its radial dike swarm, two sills from the Robinson antlicline intrusive complex, and the Ibex Mountains sill(?) gave biotite plateau dates ranging from 50.03 to 50.22 Ma, with 2σ errors of ± 0.11 to 0.19 Ma. Because these dates are from fairly small, hypabyssal intrusions, they must have cooled quickly and thus these dates closely approximate the emplacement age of the intrusions. These data indicate that the strongly alkaline intrusions were emplaced during a fairly restricted

  17. Record Dynamics in Ants

    PubMed Central

    Richardson, Thomas O.; Robinson, Elva J. H.; Christensen, Kim; Jensen, Henrik J.; Franks, Nigel R.; Sendova-Franks, Ana B.

    2010-01-01

    The success of social animals (including ourselves) can be attributed to efficiencies that arise from a division of labour. Many animal societies have a communal nest which certain individuals must leave to perform external tasks, for example foraging or patrolling. Staying at home to care for young or leaving to find food is one of the most fundamental divisions of labour. It is also often a choice between safety and danger. Here we explore the regulation of departures from ant nests. We consider the extreme situation in which no one returns and show experimentally that exiting decisions seem to be governed by fluctuating record signals and ant-ant interactions. A record signal is a new ‘high water mark’ in the history of a system. An ant exiting the nest only when the record signal reaches a level it has never perceived before could be a very effective mechanism to postpone, until the last possible moment, a potentially fatal decision. We also show that record dynamics may be involved in first exits by individually tagged ants even when their nest mates are allowed to re-enter the nest. So record dynamics may play a role in allocating individuals to tasks, both in emergencies and in everyday life. The dynamics of several complex but purely physical systems are also based on record signals but this is the first time they have been experimentally shown in a biological system. PMID:20300174

  18. Alate susceptibility in ants

    PubMed Central

    Ho, Eddie K H; Frederickson, Megan E

    2014-01-01

    Pathogens are predicted to pose a particular threat to eusocial insects because infections can spread rapidly in colonies with high densities of closely related individuals. In ants, there are two major castes: workers and reproductives. Sterile workers receive no direct benefit from investing in immunity, but can gain indirect fitness benefits if their immunity aids the survival of their fertile siblings. Virgin reproductives (alates), on the other hand, may be able to increase their investment in reproduction, rather than in immunity, because of the protection they receive from workers. Thus, we expect colonies to have highly immune workers, but relatively more susceptible alates. We examined the survival of workers, gynes, and males of nine ant species collected in Peru and Canada when exposed to the entomopathogenic fungus Beauveria bassiana. For the seven species in which treatment with B. bassiana increased ant mortality relative to controls, we found workers were significantly less susceptible compared with both alate sexes. Female and male alates did not differ significantly in their immunocompetence. Our results suggest that, as with other nonreproductive tasks in ant colonies like foraging and nest maintenance, workers have primary responsibility for colony immunity, allowing alates to specialize on reproduction. We highlight the importance of colony-level selection on individual immunity in ants and other eusocial organisms. PMID:25540683

  19. Those astronomers crazy about the skies, or the story of the observation of double stars

    NASA Astrophysics Data System (ADS)

    Ling, J. F.

    2015-05-01

    Those astronomers crazy about the skies are people who have dedicated their lives, often their fortunes, to the research and study of double stars, enigmatic star systems that like to play hide and seek while dancing a mysterious waltz. Many efforts have been made to collect the wonderful golden harvest that celestial fields provide. Starting with Sir William Herschel, organist and brilliant astronomer who documented their orbital motions, the Struve clan who undertook the first census, the Anglican priest who discovered authentic celestial jewels and all the way to current international research teams using the greatest telescopes, they all searched with the same passion. They all went beyond the mere spectacle of the eternity of these pairs, seeking the Philosopher's Stone, the secret of stellar alchemy and the means to break down the wall that imprisons our knowledge. This book is the Spanish translation of the original French text written by Paul Couteau, one of the foremost authorities on the subject. No one better than him to immerse us into the knowledge of these objects, both scientifically and historically. Despite the 25 years since its publication, the text has not lost relevance. The story never dies and the attraction that still elicits has been one of the reasons to provide readers with this Spanish translation. In addition, we have included a chapter written by Josefina F. Ling. This version, published by the Department of Publications and Scientific Communications at the University of Santiago de Compostela and partially funded by the Spanish Society of Astronomy, has an initial print of 500 copies.

  20. Utilization of Anting-Anting (Acalypha indica) Leaves as Antibacterial

    NASA Astrophysics Data System (ADS)

    Batubara, Irmanida; Wahyuni, Wulan Tri; Firdaus, Imam

    2016-01-01

    Anting-anting (Acalypha indica) plants is a species of plant having catkin type of inflorescence. This research aims to utilize anting-anting as antibacterial toward Streptococcus mutans and degradation of biofilm on teeth. Anting-anting leaves were extracted by maceration technique using methanol, chloroform, and n-hexane. Antibacterial and biofilm degradation assays were performed using microdilution technique with 96 well. n-Hexane extracts of anting-anting leaves gave the best antibacterial potency with minimum inhibitory concentration and minimum bactericidal concentration value of 500 μg/mL and exhibited good biofilm degradation activity. Fraction of F3 obtained from fractionation of n-hexane's extract with column chromatography was a potential for degradation of biofilm with IC50 value of 56.82 μg/mL. Alkaloid was suggested as antibacterial and degradation of biofilm in the active fraction.

  1. The Ants Go Marching Millions by Millions: Invasive Ant Research

    USDA-ARS?s Scientific Manuscript database

    Invasive ants are a worldwide problem that is expanding both geographically and in intensity. Population explosions of invasive ants can overrun landscapes and inundate structures. Pest management professionals are often the first responders to complaints about invading ants. This session will fo...

  2. The ants go marching millions by millions: invasive ant research

    USDA-ARS?s Scientific Manuscript database

    Invasive ants are a worldwide problem that is expanding both geographically and in intensity. Population explosions of invasive ants can overrun landscapes and inundate structures. Pest management professionals are often the first responders to complaints about invading ants. This session will fo...

  3. Clinical holistic medicine: factors influencing the therapeutic decision-making. From academic knowledge to emotional intelligence and spiritual "crazy" wisdom.

    PubMed

    Ventegodt, Søren; Kandel, Isack; Merrick, Joav

    2007-12-10

    Scientific holistic medicine is built on holistic medical theory, on therapeutic and ethical principles. The rationale is that the therapist can take the patient into a state of salutogenesis, or existential healing, using his skills and knowledge. But how ever much we want to make therapy a science it remains partly an art, and the more developed the therapist becomes, the more of his/her decisions will be based on intuition, feeling and even inspiration that is more based on love and human concern and other spiritual motivations than on mental reason and rationality in a simple sense of the word. The provocative and paradoxal medieval western concept of the "truth telling clown", or the eastern concepts of "crazy wisdom" and "holy madness" seems highly relevant here. The problem is how we can ethically justify this kind of highly "irrational" therapeutic behavior in the rational setting of a medical institution. We argue here that holistic therapy has a very high success rate and is doing no harm to the patient, and encourage therapists, psychiatrists, psychologist and other academically trained "helpers" to constantly measure their own success-rate. This paper discusses many of the important factors that influence clinical holistic decision-making. Sexuality could, as many psychoanalysts from Freud to Reich and Searles have believed, be the most healing power that exists and also the most difficult for the mind to comprehend, and thus the most "crazy-wise" tool of therapy.

  4. Ants: the supreme soil manipulators

    USDA-ARS?s Scientific Manuscript database

    This review focuses on the semiochemical interactions between ants and their soil environment. Ants occupy virtually every ecological niche and have evolved mechanisms to not just cope with, but also manipulate soil organisms. The metapleural gland, specific to ants was thought to be the major sourc...

  5. Distributed nestmate recognition in ants.

    PubMed

    Esponda, Fernando; Gordon, Deborah M

    2015-05-07

    We propose a distributed model of nestmate recognition, analogous to the one used by the vertebrate immune system, in which colony response results from the diverse reactions of many ants. The model describes how individual behaviour produces colony response to non-nestmates. No single ant knows the odour identity of the colony. Instead, colony identity is defined collectively by all the ants in the colony. Each ant responds to the odour of other ants by reference to its own unique decision boundary, which is a result of its experience of encounters with other ants. Each ant thus recognizes a particular set of chemical profiles as being those of non-nestmates. This model predicts, as experimental results have shown, that the outcome of behavioural assays is likely to be variable, that it depends on the number of ants tested, that response to non-nestmates changes over time and that it changes in response to the experience of individual ants. A distributed system allows a colony to identify non-nestmates without requiring that all individuals have the same complete information and helps to facilitate the tracking of changes in cuticular hydrocarbon profiles, because only a subset of ants must respond to provide an adequate response.

  6. Non-native Ants Are Smaller than Related Native Ants.

    PubMed

    McGlynn, Terrence P

    1999-12-01

    I compare the sizes of non-native and native ants to evaluate how worker size may be related to the ability of a species to invade new habitats. I compare the size of 78 non-native ant species belonging to 26 genera with the size of native congeneric species; native ants are larger than non-native ants in 22 of 26 genera. Ants were sorted by genera into fighting and nonfighting groups, based on observations of interspecific interactions with other ant species. In all of the genera with monomorphic worker castes that fight during competition, the non-native species were smaller than the native species. The genera that engage in combat had a higher frequency of significantly smaller size in non-native ants. I selected Wasmannia auropunctata for further studies, to compare native and non-native populations. Specimens of W. auropunctata from non-native populations were smaller than conspecific counterparts from its native habitat. I consider hypotheses to explain why non-native ants are smaller in size than native ants, including the role of colony size in interspecific fights, changes in life history, the release from intraspecific fighting, and climate. The discovery that fighting non-natives are smaller than their closest native relatives may provide insight into the mechanisms for success of non-native species, as well as the role of worker size and colony size during interspecific competition.

  7. Ant algorithms for discrete optimization.

    PubMed

    Dorigo, M; Di Caro, G; Gambardella, L M

    1999-01-01

    This article presents an overview of recent work on ant algorithms, that is, algorithms for discrete optimization that took inspiration from the observation of ant colonies' foraging behavior, and introduces the ant colony optimization (ACO) metaheuristic. In the first part of the article the basic biological findings on real ants are reviewed and their artificial counterparts as well as the ACO metaheuristic are defined. In the second part of the article a number of applications of ACO algorithms to combinatorial optimization and routing in communications networks are described. We conclude with a discussion of related work and of some of the most important aspects of the ACO metaheuristic.

  8. Fire ant microsporidia acquired by parasitoid flies of fire ants

    USDA-ARS?s Scientific Manuscript database

    The microsporidium Kneallhazia (formerly Thelohania) solenopsae and parasitoid flies in the genus Pseudacteon are natural enemies of the invasive fire ant, Solenopsis invicta. Pseudacteon flies oviposit into adult fire ants, where maggots that eclose from eggs migrate to the ants’ head, pupate, and...

  9. Temperature: Human Regulating, Ants Conforming

    ERIC Educational Resources Information Center

    Clopton, Joe R.

    2007-01-01

    Biological processes speed up as temperature rises. Procedures for demonstrating this with ants traveling on trails, and data gathered by students on the Argentine ant ("Linepithema humile") are presented. The concepts of temperature regulation and conformity are detailed with a focus on the processes rather than on terms that label the organisms.

  10. Orchid seed removal by ants in Neotropical ant-gardens.

    PubMed

    Morales-Linares, J; García-Franco, J G; Flores-Palacios, A; Valenzuela-González, J E; Mata-Rosas, M; Díaz-Castelazo, C

    2018-05-01

    Most plants that inhabit ant-gardens (AGs) are cultivated by the ants. Some orchids occur in AGs; however, it is not known whether their seeds are dispersed by AG ants because most orchid seeds are tiny and dispersed by wind. We performed in situ seed removal experiments, in which we simultaneously provided Azteca gnava ants with seeds of three AG orchid species and three other AG epiphyte species (Bromeliaceae, Cactaceae and Gesneriaceae), as well as the non-AG orchid Catasetum integerrimum. The seeds most removed were those of the bromeliad Aechmea tillandsioides and the gesneriad Codonanthe uleana, while seeds of AG orchids Coryanthes picturata, Epidendrum flexuosum and Epidendrum pachyrachis were less removed. The non-AG orchid was not removed. Removal values were positively correlated with the frequency of the AG epiphytes in the AGs, and seeds of AG orchids were larger than those of non-AG orchids, which should favour myrmecochory. Our data show that Azt. gnava ants discriminate and preferentially remove seeds of the AG epiphytes. We report for the first time the removal of AG orchid seeds by AG ants in Neotropical AGs. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  11. Imported fire ants in the southeast

    Treesearch

    David F. Williams

    1998-01-01

    Two species of imported fire ants were introduced into the U.S. at Mobile, Alabama. The black imported fire ant, Solenopsis richteri Forel, was introduced around the early 1900's while the red imported fire ant, Solenopsis invicta Buren entered in the late 1930' or early 1940's. The red imported fire ant is the most...

  12. Monoculture of Leafcutter Ant Gardens

    PubMed Central

    Mueller, Ulrich G.; Scott, Jarrod J.; Ishak, Heather D.; Cooper, Michael; Rodrigues, Andre

    2010-01-01

    Background Leafcutter ants depend on the cultivation of symbiotic Attamyces fungi for food, which are thought to be grown by the ants in single-strain, clonal monoculture throughout the hundreds to thousands of gardens within a leafcutter nest. Monoculture eliminates cultivar-cultivar competition that would select for competitive fungal traits that are detrimental to the ants, whereas polyculture of several fungi could increase nutritional diversity and disease resistance of genetically variable gardens. Methodology/Principal Findings Using three experimental approaches, we assessed cultivar diversity within nests of Atta leafcutter ants, which are most likely among all fungus-growing ants to cultivate distinct cultivar genotypes per nest because of the nests' enormous sizes (up to 5000 gardens) and extended lifespans (10–20 years). In Atta texana and in A. cephalotes, we resampled nests over a 5-year period to test for persistence of resident cultivar genotypes within each nest, and we tested for genetic differences between fungi from different nest sectors accessed through excavation. In A. texana, we also determined the number of Attamyces cells carried as a starter inoculum by a dispersing queens (minimally several thousand Attamyces cells), and we tested for genetic differences between Attamyces carried by sister queens dispersing from the same nest. Except for mutational variation arising during clonal Attamyces propagation, DNA fingerprinting revealed no evidence for fungal polyculture and no genotype turnover during the 5-year surveys. Conclusions/Significance Atta leafcutter ants can achieve stable, fungal monoculture over many years. Mutational variation emerging within an Attamyces monoculture could provide genetic diversity for symbiont choice (gardening biases of the ants favoring specific mutational variants), an analog of artificial selection. PMID:20844760

  13. Gaseous templates in ant nests.

    PubMed

    Cox, M D; Blanchard, G B

    2000-05-21

    We apply a diffusion model to the atmosphere of ant nests. With particular reference to carbon dioxide (CO2), we explore analytically and numerically the spatial and temporal patterns of brood- or worker-produced gases in nests. The maximum concentration within a typical one-chamber ant nest with approximately 200 ants can reach 12.5 times atmospheric concentration, reaching 95% of equilibrium concentrations within 15 min. Maximum concentration increases with increasing number of ants in the nest (or production rate of the gas), distance between the centre of the nest ants and the nest entrance, entrance length, wall thickness, and with decreasing entrance width, wall permeability and diffusion coefficient. The nest can be divided into three qualitatively distinct regions according to the shape of the gradient: a plateau of high concentration in the back half of the nest; an intermediate region of increasingly steep gradient towards the entrance; and a steep linear gradient in the entrance tunnel. These regions are robust to changes in gas concentrations, but vary with changes in nest architecture. The pattern of diffusing gases contains information about position and orientation relative to gas sources and sinks, and about colony state, including colony size, activity state and aspects of nest architecture. We discuss how this diffusion pattern may act as a "dynamic template", providing local cues which trigger behavioural acts appropriate to colony needs, which in turn may feed back to changes in the gas template. In particular, wall building occurs along lines of similar concentration for a variety of nest geometries; there is surprising convergence between the period of cycles of synchronously active ants and the time taken for CO2 levels to equilibrate; and the qualitatively distinct regions of the "dynamic template" correspond to regions occupied by different groups of ants.

  14. How Ants Drop Out: Ant Abundance on Tropical Mountains

    PubMed Central

    Longino, John T.; Branstetter, Michael G.; Colwell, Robert K.

    2014-01-01

    In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops. PMID:25098722

  15. How ants drop out: ant abundance on tropical mountains.

    PubMed

    Longino, John T; Branstetter, Michael G; Colwell, Robert K

    2014-01-01

    In tropical wet forests, ants are a large proportion of the animal biomass, but the factors determining abundance are not well understood. We characterized ant abundance in the litter layer of 41 mature wet forest sites spread throughout Central America (Chiapas, Guatemala, Honduras, Nicaragua, and Costa Rica) and examined the impact of elevation (as a proxy for temperature) and community species richness. Sites were intentionally chosen to minimize variation in precipitation and seasonality. From sea level to 1500 m ant abundance very gradually declined, community richness declined more rapidly than abundance, and the local frequency of the locally most common species increased. These results suggest that within this elevational zone, density compensation is acting, maintaining high ant abundance as richness declines. In contrast, in sites above 1500 m, ant abundance dropped abruptly to much lower levels. Among these high montane sites, community richness explained much more of the variation in abundance than elevation, and there was no evidence of density compensation. The relative stability of abundance below 1500 m may be caused by opposing effects of temperature on productivity and metabolism. Lower temperatures may decrease productivity and thus the amount of food available for consumers, but slower metabolisms of consumers may allow maintenance of higher biomass at lower resource supply rates. Ant communities at these lower elevations may be highly interactive, the result of continuous habitat presence over geological time. High montane sites may be ephemeral in geological time, resulting in non-interactive communities dominated by historical and stochastic processes. Abundance in these sites may be determined by the number of species that manage to colonize and/or avoid extinction on mountaintops.

  16. Macroevolutionary assembly of ant/plant symbioses: Pseudomyrmex ants and their ant-housing plants in the Neotropics

    PubMed Central

    Chomicki, Guillaume; Ward, Philip S.; Renner, Susanne S.

    2015-01-01

    Symbioses include some of the clearest cases of coevolution, but their origin, loss or reassembly with different partners can rarely be inferred. Here we use ant/plant symbioses involving three plant clades to investigate the evolution of symbioses. We generated phylogenies for the big-eyed arboreal ants (Pseudomyrmecinae), including 72% of their 286 species, as well as for five of their plant host groups, in each case sampling more than 61% of the species. We show that the ant-housing Vachellia (Mimosoideae) clade and its ants co-diversified for the past 5 Ma, with some species additionally colonized by younger plant-nesting ant species, some parasitic. An apparent co-radiation of ants and Tachigali (Caesalpinioideae) was followed by waves of colonization by the same ant clade, and subsequent occupation by a younger ant group. Wide crown and stem age differences between the ant-housing genus Triplaris (Polygonaceae) and its obligate ant inhabitants, and stochastic trait mapping, indicate that its domatium evolved earlier than the ants now occupying it, suggesting previous symbioses that dissolved. Parasitic ant species evolved from generalists, not from mutualists, and are younger than the mutualistic systems they parasitize. Our study illuminates the macroevolutionary assembly of ant/plant symbioses, which has been highly dynamic, even in very specialized systems. PMID:26582029

  17. Optimal cue integration in ants.

    PubMed

    Wystrach, Antoine; Mangan, Michael; Webb, Barbara

    2015-10-07

    In situations with redundant or competing sensory information, humans have been shown to perform cue integration, weighting different cues according to their certainty in a quantifiably optimal manner. Ants have been shown to merge the directional information available from their path integration (PI) and visual memory, but as yet it is not clear that they do so in a way that reflects the relative certainty of the cues. In this study, we manipulate the variance of the PI home vector by allowing ants (Cataglyphis velox) to run different distances and testing their directional choice when the PI vector direction is put in competition with visual memory. Ants show progressively stronger weighting of their PI direction as PI length increases. The weighting is quantitatively predicted by modelling the expected directional variance of home vectors of different lengths and assuming optimal cue integration. However, a subsequent experiment suggests ants may not actually compute an internal estimate of the PI certainty, but are using the PI home vector length as a proxy. © 2015 The Author(s).

  18. Termites, hemimetabolous diploid white ants?

    PubMed

    Korb, Judith

    2008-09-29

    Ants and termites are the most abundant animals on earth. Their ecological success is attributed to their social life. They live in colonies consisting of few reproducing individuals, while the large majority of colony members (workers/soldiers) forego reproduction at least temporarilly. Despite their apparent resemblance in social organisation, both groups evolved social life independently. Termites are basically social cockroaches, while ants evolved from predatory wasps. In this review, I will concentrate on termites with an ancestral life type, the wood-dwelling termites, to compare them with ants. Their different ancestries provided both groups with different life history pre-adaptations for social evolution. Like their closest relatives, the woodroaches, wood-dwelling termites live inside their food, a piece of wood. Thus, intensive costly food provisioning of their young is not necessary, especially as young instars are rather independent due to their hemimetabolous development. In contrast, ants are progressive food provisioners which have to care intensively for their helpless brood. Corresponding to the precocial - altricial analogy, helping by workers is selected in ants, while new evidence suggests that wood-dwelling termite workers are less engaged in brood care. Rather they seem to stay in the nest because there is generally low selection for dispersal. The nest presents a safe haven with no local resource competition as long as food is abundant (which is generally the case), while founding a new colony is very risky. Despite these differences between ants and termites, their common dwelling life style resulted in convergent evolution, especially winglessness, that probably accounts for the striking similarity between both groups. In ants, all workers are wingless and winglessness in sexuals evolved in several taxa as a derived trait. In wood-dwelling termites, workers are by default wingless as they are immatures. These immatures can develop into

  19. Using Ants To Investigate the Environment.

    ERIC Educational Resources Information Center

    Hagevik, Rita A.

    2003-01-01

    Describes three inquiry-based activities designed for students to begin to understand complex environmental relationships in their own backyard. Includes investigations of ants, which allow students to establish a baseline survey of ant fauna, test the importance of ants in nutrient cycling and soil structure maintenances, and increase student…

  20. Using Ants to Investigate the Environment

    ERIC Educational Resources Information Center

    Hagevik, Rita A.

    2005-01-01

    The best place for students to begin to understand complex environmental relationships is in their own back yards. Doing investigations of ants allows students to establish a baseline survey of ant fauna, test the importance of ants in nutrient cycling and soil structure maintenance, and increase their understanding of the environment and their…

  1. Methods for Casting Subterranean Ant Nests

    PubMed Central

    Tschinkel, Walter R.

    2010-01-01

    The study of subterranean ant nests has been impeded by the difficulty of rendering their structures in visible form. Here, several different casting materials are shown to make perfect casts of the underground nests of ants. Each material (dental plaster, paraffin wax, aluminum, zinc) has advantages and limitations, which are discussed. Some of the materials allow the recovery of the ants entombed in the casts, allowing a census of the ants to be connected with features of their nest architecture. The necessary equipment and procedures are described in the hope that more researchers will study this very important aspect of ant natural history. PMID:20673073

  2. Quantifying Ant Activity Using Vibration Measurements

    PubMed Central

    Oberst, Sebastian; Baro, Enrique Nava; Lai, Joseph C. S.; Evans, Theodore A.

    2014-01-01

    Ant behaviour is of great interest due to their sociality. Ant behaviour is typically observed visually, however there are many circumstances where visual observation is not possible. It may be possible to assess ant behaviour using vibration signals produced by their physical movement. We demonstrate through a series of bioassays with different stimuli that the level of activity of meat ants (Iridomyrmex purpureus) can be quantified using vibrations, corresponding to observations with video. We found that ants exposed to physical shaking produced the highest average vibration amplitudes followed by ants with stones to drag, then ants with neighbours, illuminated ants and ants in darkness. In addition, we devised a novel method based on wavelet decomposition to separate the vibration signal owing to the initial ant behaviour from the substrate response, which will allow signals recorded from different substrates to be compared directly. Our results indicate the potential to use vibration signals to classify some ant behaviours in situations where visual observation could be difficult. PMID:24658467

  3. Revolutionizing Remote Exploration with ANTS

    NASA Astrophysics Data System (ADS)

    Clark, P. E.; Rilee, M. L.; Curtis, S.; Truszkowski, W.

    2002-05-01

    We are developing the Autonomous Nano-Technology Swarm (ANTS) architecture based on an insect colony analogue for the cost-effective, efficient, systematic survey of remote or inaccessible areas with multiple object targets, including planetary surface, marine, airborne, and space environments. The mission context is the exploration in the 2020s of the most compelling remaining targets in the solar system: main belt asteroids. Main belt asteroids harbor important clues to Solar System origins and evolution which are central to NASA's goals in Space Science. Asteroids are smaller than planets, but their number is far greater, and their combined surface area likely dwarfs the Earth's. An asteroid survey will dramatically increase our understanding of the local resources available for the Human Exploration and Development of Space. During the mission composition, shape, gravity, and orbit parameters could be returned to Earth for perhaps several thousand asteroids. A survey of this area will rival the great explorations that encircled this globe, opened up the New World, and laid the groundwork for the progress and challenges of the last centuries. The ANTS architecture for a main belt survey consists of a swarm of as many as a thousand or more highly specialized pico-spacecraft that form teams to survey as many as one hundred asteroids a month. Multi-level autonomy is critical for ANTS and the objective of the proposed study is to work through the implications and constraints this entails. ANTS couples biologically inspired autonomic control for basic functions to higher level artificial intelligence that together enable individual spacecraft to operate as specialized, cooperative, social agents. This revolutionary approach postulates highly advanced, but familiar, components integrated and operated in a way that uniquely transcends any evolutionary extrapolation of existing trends and enables thousand-spacecraft missions.

  4. Ant-plant mutualism: a dietary by-product of a tropical ant's macronutrient requirements.

    PubMed

    Arcila Hernández, Lina M; Sanders, Jon G; Miller, Gabriel A; Ravenscraft, Alison; Frederickson, Megan E

    2017-12-01

    Many arboreal ants depend on myrmecophytic plants for both food and shelter; in return, these ants defend their host plants against herbivores, which are often insects. Ant-plant and other mutualisms do not necessarily involve the exchange of costly rewards or services; they may instead result from by-product benefits, or positive outcomes that do not entail a cost for one or both partners. Here, we examined whether the plant-ant Allomerus octoarticulatus pays a short-term cost to defend their host plants against herbivores, or whether plant defense is a by-product benefit of ant foraging for insect prey. Because the food offered by ant-plants is usually nitrogen-poor, arboreal ants may balance their diets by consuming insect prey or associating with microbial symbionts to acquire nitrogen, potentially shifting the costs and benefits of plant defense for the ant partner. To determine the effect of ant diet on an ant-plant mutualism, we compared the behavior, morphology, fitness, stable isotope signatures, and gaster microbiomes of A. octoarticulatus ants nesting in Cordia nodosa trees maintained for nearly a year with or without insect herbivores. At the end of the experiment, ants from herbivore exclosures preferred protein-rich baits more than ants in the control (i.e., herbivores present) treatment. Furthermore, workers in the control treatment were heavier than in the herbivore-exclusion treatment, and worker mass predicted reproductive output, suggesting that foraging for insect prey directly increased ant colony fitness. The gaster microbiome of ants was not significantly affected by the herbivore exclusion treatment. We conclude that the defensive behavior of some phytoecious ants is a by-product of their need for external protein sources; thus, the consumption of insect herbivores by ants benefits both the ant colony and the host plant. © 2017 by the Ecological Society of America.

  5. Roadside Survey of Ants on Oahu, Hawaii

    PubMed Central

    Tong, Reina L.; Grace, J. Kenneth; Krushelnycky, Paul D.

    2018-01-01

    Hawaii is home to over 60 ant species, including five of the six most damaging invasive ants. Although there have been many surveys of ants in Hawaii, the last island-wide hand-collection survey of ants on Oahu was conducted in 1988–1994. In 2012, a timed hand-collection of ants was made at 44 sites in a systematic, roadside survey throughout Oahu. Ants were identified and species distribution in relation to elevation, precipitation and soil type was analyzed. To assess possible convenience sampling bias, 15 additional sites were sampled further from roads to compare with the samples near roads. Twenty-four species of ants were found and mapped; Pheidole megacephala (F.), Ochetellus glaber (Mayr), and Technomyrmex difficilis Forel were the most frequently encountered ants. For six ant species, a logistic regression was performed with elevation, average annual precipitation, and soil order as explanatory variables. O. glaber was found in areas with lower precipitation around Oahu. Paratrechina longicornis (Latrielle) and Tetramorium simillimum (Smith, F.) were found more often in lower elevations and in areas with the Mollisol soil order. Elevation, precipitation, and soil type were not significant sources of variation for P. megacephala, Plagiolepis alluaudi Emery, and T. difficilis. P. megacephala was associated with fewer mean numbers of ants where it occurred. Ant assemblages near and far from roads did not significantly differ. Many species of ants remain established on Oahu, and recent invaders are spreading throughout the island. Mapping ant distributions contributes to continued documentation and understanding of these pests. PMID:29439503

  6. Microorganisms transported by ants induce changes in floral nectar composition of an ant-pollinated plant.

    PubMed

    de Vega, Clara; Herrera, Carlos M

    2013-04-01

    Interactions between plants and ants abound in nature and have significant consequences for ecosystem functioning. Recently, it has been suggested that nectar-foraging ants transport microorganisms to flowers; more specifically, they transport yeasts, which can potentially consume sugars and alter nectar composition. Therefore, ants could indirectly change nectar sugar profile, an important floral feature involved in the plant-pollinator mutualism. But this novel role for ants has never been tested. We here investigate the effects of nectarivorous ants and their associated yeasts on the floral nectar sugar composition of an ant-pollinated plant. Differences in the nectar sugar composition of ant-excluded and ant-visited flowers were examined in 278 samples by using high-performance liquid-chromatography. The importance of the genetic identity and density of ant-transported basidiomycetous and ascomycetous yeasts on the variation of nectar traits was also evaluated. Ant visitation had significant effects on nectar sugar composition. The nectar of ant-visited flowers contained significantly more fructose, more glucose, and less sucrose than the nectar of ant-excluded flowers, but these effects were context dependent. Nectar changes were correlated with the density of yeast cells in nectar. The magnitude of the effects of ant-transported ascomycetes was much higher than that of basiodiomycetes. Ants and their associated yeasts induce changes in nectar sugar traits, reducing the chemical control of the plant over this important floral trait. The potential relevance of this new role for ants as indirect nectar modifiers is a rich topic for future research into the ecology of ant-flower interactions.

  7. Usefulness of fire ant genetics in insecticide efficacy trials

    USDA-ARS?s Scientific Manuscript database

    Mature fire ant colonies contain an average of 80,000 worker ants. For this study, eight fire ant workers were randomly sampled from each colony. DNA fingerprints for each individual ant were generated using 21 simple sequence repeats (SSR) markers that were developed from fire ant DNA by other lab...

  8. Crazy about Empowerment?

    ERIC Educational Resources Information Center

    Kizilos, Peter

    1990-01-01

    Discusses empowerment, the process of coming to feel and behave as though one has power over significant aspect of one's life or work, as it relates to employee productivity, motivation, and behavior. (JOW)

  9. Crazy Quilt Project

    ERIC Educational Resources Information Center

    Flood, LaDora

    2007-01-01

    One of the author's earliest recollections is going with her mother up into her grandmother's bedroom to look in a very old chest. The chest contains quilts that have been in the family for generations. Fascinated by quilt colors, designs, and tiny stitches, the author shares this with her fifth-grade classes by making a paper quilt at school.…

  10. Sensible and Crazy Numbers

    ERIC Educational Resources Information Center

    Russo, James

    2017-01-01

    Using a game-based context and concentrating explicitly on language, students in the early years are able to make sense about place value amid the vagaries of the English language in naming numbers. This conceptual approach to understanding place value allows students to further develop number strategies beyond counting by ones.

  11. CES 2011: Tablet Crazy

    ERIC Educational Resources Information Center

    Rapp, David

    2011-01-01

    Ereaders are so last year. Tablets were the watchword at this year's annual Consumer Electronics Show (CES) in Las Vegas, January 6-9. This year, the show set new records, with some 2700 companies from around the world exhibiting at the multiple exhibition halls and 30,000 attendees gawking at the products. What did they see? There were still some…

  12. Crazy about Crayfish

    ERIC Educational Resources Information Center

    Endreny, Anna

    2006-01-01

    Crayfish, also known as "crawfish" or "crawdads," are easy to keep in the classroom, and with patience and luck, students will observe the complete life cycle of the crayfish. They will also learn about aquatic animals and habitats and get to conduct inquiry experiments about animal behavior. This article describes how a third-grade teacher used…

  13. Conflict resolution in an ant-plant interaction: Acacia constricta traits reduce ant costs to reproduction.

    PubMed

    Nicklen, E Fleur; Wagner, Diane

    2006-05-01

    Many plant species attract ants onto their foliage with food rewards or nesting space. However, ants can interfere with plant reproduction when they visit flowers. This study tests whether Acacia constricta separates visiting ant species temporally or spatially from newly opened inflorescences and pollinators. The diurnal activity patterns of ants and A. constricta pollinators peaked at different times of day, and the activity of pollinators followed the daily dehiscence of A. constricta inflorescences. In addition to being largely temporally separated, ants rarely visited open inflorescences. A floral ant repellent contributes to the spatial separation of ants and inflorescences. In a field experiment, ants of four species were given equal access to inflorescences in different developmental stages. On average, the frequency with which ants made initial, antennal contact with the floral stages did not differ, but ants significantly avoided secondary contact with newly opened inflorescences relative to buds and old inflorescences, and old inflorescences relative to buds. Ants also avoided contact with pollen alone, indicating that pollen is at least one source of the repellent. The results suggest A. constricta has effectively resolved the potential conflict between visiting ants and plant reproduction.

  14. Plants in Your Ants: Using Ant Mounds to Test Basic Ecological Principles

    ERIC Educational Resources Information Center

    Zettler, Jennifer A.; Collier, Alexander; Leidersdorf, Bil; Sanou, Missa Patrick

    2010-01-01

    Urban students often have limited access to field sites for ecological studies. Ubiquitous ants and their mounds can be used to study and test ecology-based questions. We describe how soil collected from ant mounds can be used to investigate how biotic factors (ants) can affect abiotic factors in the soil that can, in turn, influence plant growth.

  15. Spectacular Batesian mimicry in ants

    NASA Astrophysics Data System (ADS)

    Ito, Fuminori; Hashim, Rosli; Huei, Yek Sze; Kaufmann, Eva; Akino, Toshiharu; Billen, Johan

    2004-10-01

    The mechanism by which palatable species take advantage of their similarity in appearance to those that are unpalatable, in order to avoid predation, is called Batesian mimicry. Several arthropods are thought to be Batesian mimics of social insects; however, social insects that are Batesian mimics among themselves are rare. In Malaysia we found a possible Batesian mimic in an arboreal ant species, Camponotus sp., which was exclusively observed on foraging trails of the myrmicine ant Crematogaster inflata. The bright yellow and black colouring pattern, as well as the walking behaviour, were very similar in both species. We observed general interactions between the two species, and tested their palatability and the significance of the remarkably similar visual colour patterns for predator avoidance. Prey offered to C. inflata was also eaten by Camponotus workers in spite of their being attacked by C. inflata, indicating that Camponotus sp. is a commensal of C. inflata. An experiment with chicks as potential predators suggests that Camponotus sp. is palatable whereas C. inflata is unpalatable. After tasting C. inflata, the chicks no longer attacked Camponotus sp., indicating that Camponotus sp. is a Batesian mimic of Crematogaster inflata.

  16. Extrafloral nectar fuels ant life in deserts.

    PubMed

    Aranda-Rickert, Adriana; Diez, Patricia; Marazzi, Brigitte

    2014-11-07

    Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal desert of northwestern Argentina, we surveyed the richness and phenology of EFN plants and their associated ants and examined the patterns in ant-plant interaction networks. We found that 25 ant species and 11 EFN-bearing plant species were linked together through 96 pairs of associations. Plants bearing EFNs were abundant, representing ca. 19 % of the species encountered in transects and 24 % of the plant cover. Most ant species sampled (ca. 77 %) fed on EF nectar. Interactions showed a marked seasonal pattern: EFN secretion was directly related to plant phenology and correlated with the time of highest ant ground activity. Our results reveal that EFN-mediated interactions are ecologically relevant components of deserts, and that EFN-bearing plants are crucial for the survival of desert ant communities. Published by Oxford University Press on behalf of the Annals of Botany Company.

  17. Urban Pest Management of Ants in California

    USDA-ARS?s Scientific Manuscript database

    Keeping pace with the dynamic and evolving landscape of invasive ants in California presents a formidable challenge to the pest management industry. Pest management professionals (PMPs) are on the frontlines when it comes to battling these exotic ant pests, and are often the first ones to intercept ...

  18. The Use of Ants in Field Work.

    ERIC Educational Resources Information Center

    Skinner, Gary J.

    1988-01-01

    Provided is a brief description of the biology and taxonomy of British ants. Suggested are a range of exercises which could be used for class or project work in secondary biology classes. Illustrates many ecological, behavioral and physiological points regarding the species of ants found in Great Britain. (Author/CW)

  19. Improving Emergency Management by Modeling Ant Colonies

    DTIC Science & Technology

    2015-03-01

    LEFT BLANK vii TABLE OF CONTENTS I.  THE INCIDENT COMMAND SYSTEM AND AUTONOMOUS ACTORS ......1  A.  PROBLEM STATEMENT...managerial level tasking.12 The Oklahoma City bombing has generally been viewed as a success for the ICS model; however, there were numerous occurrences...developed. The youngest generation of ant 25 Bert Holldobler and Edward O. Wilson, The Ants

  20. Hey! A Fire Ant Stung Me!

    MedlinePlus

    ... Staying Safe Videos for Educators Search English Español Hey! A Fire Ant Stung Me! KidsHealth / For Kids / Hey! A Fire Ant Stung Me! Print en español ¡ ... with it. More on this topic for: Kids Hey! A Bee Stung Me! Hey! A Scorpion Stung ...

  1. The Biochemical Toxin Arsenal from Ant Venoms

    PubMed Central

    Touchard, Axel; Aili, Samira R.; Fox, Eduardo Gonçalves Paterson; Escoubas, Pierre; Orivel, Jérôme; Nicholson, Graham M.; Dejean, Alain

    2016-01-01

    Ants (Formicidae) represent a taxonomically diverse group of hymenopterans with over 13,000 extant species, the majority of which inject or spray secretions from a venom gland. The evolutionary success of ants is mostly due to their unique eusociality that has permitted them to develop complex collaborative strategies, partly involving their venom secretions, to defend their nest against predators, microbial pathogens, ant competitors, and to hunt prey. Activities of ant venom include paralytic, cytolytic, haemolytic, allergenic, pro-inflammatory, insecticidal, antimicrobial, and pain-producing pharmacologic activities, while non-toxic functions include roles in chemical communication involving trail and sex pheromones, deterrents, and aggregators. While these diverse activities in ant venoms have until now been largely understudied due to the small venom yield from ants, modern analytical and venomic techniques are beginning to reveal the diversity of toxin structure and function. As such, ant venoms are distinct from other venomous animals, not only rich in linear, dimeric and disulfide-bonded peptides and bioactive proteins, but also other volatile and non-volatile compounds such as alkaloids and hydrocarbons. The present review details the unique structures and pharmacologies of known ant venom proteinaceous and alkaloidal toxins and their potential as a source of novel bioinsecticides and therapeutic agents. PMID:26805882

  2. Ant-seed mutualisms: Can red imported fire ants sour the relationship?

    USGS Publications Warehouse

    Zettler, J.A.; Spira, T.P.; Allen, Craig R.

    2001-01-01

    Invasion by the red imported fire ant, Solenopsis invicta, has had negative impacts on individual animal and plant species, but little is known about how S. invicta affects complex mutualistic relationships. In some eastern forests of North America, 30% of herbaceous species have ant-dispersed seeds. We conducted experiments to determine if fire ants are attracted to seeds of these plant species and assessed the amount of scarification or damage that results from handling by fire ants. Fire ants removed nearly 100% of seeds of the ant-dispersed plants Trillium undulatum, T. discolor, T. catesbaei, Viola rotundifolia, and Sanguinaria canadensis. In recovered seeds fed to ant colonies, fire ants scarified 80% of S. canadensis seeds and destroyed 86% of V. rotundifolia seeds. Our study is the first to document that red imported fire ants are attracted to and remove seeds of species adapted for ant dispersal. Moreover, fire ants might damage these seeds and discard them in sites unfavorable for germination and seedling establishment. ?? 2001 Elsevier Science Ltd. All rights reserved.

  3. Ant aggression and evolutionary stability in plant-ant and plant-pollinator mutualistic interactions.

    PubMed

    Oña, L; Lachmann, M

    2011-03-01

    Mutualistic partners derive a benefit from their interaction, but this benefit can come at a cost. This is the case for plant-ant and plant-pollinator mutualistic associations. In exchange for protection from herbivores provided by the resident ants, plants supply various kinds of resources or nests to the ants. Most ant-myrmecophyte mutualisms are horizontally transmitted, and therefore, partners share an interest in growth but not in reproduction. This lack of alignment in fitness interests between plants and ants drives a conflict between them: ants can attack pollinators that cross-fertilize the host plants. Using a mathematical model, we define a threshold in ant aggressiveness determining pollinator survival or elimination on the host plant. In our model we observed that, all else being equal, facultative interactions result in pollinator extinction for lower levels of ant aggressiveness than obligatory interactions. We propose that the capacity to discriminate pollinators from herbivores should not often evolve in ants, and when it does it will be when the plants exhibit limited dispersal in an environment that is not seed saturated so that each seed produced can effectively generate a new offspring or if ants acquire an extra benefit from pollination (e.g. if ants eat fruit). We suggest specific mutualism examples where these hypotheses can be tested empirically. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

  4. Ants defend aphids against lethal disease

    PubMed Central

    Nielsen, Charlotte; Agrawal, Anurag A.; Hajek, Ann E.

    2010-01-01

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  5. Recurrence analysis of ant activity patterns

    PubMed Central

    2017-01-01

    In this study, we used recurrence quantification analysis (RQA) and recurrence plots (RPs) to compare the movement activity of individual workers of three ant species, as well as a gregarious beetle species. RQA and RPs quantify the number and duration of recurrences of a dynamical system, including a detailed quantification of signals that could be stochastic, deterministic, or both. First, we found substantial differences between the activity dynamics of beetles and ants, with the results suggesting that the beetles have quasi-periodic dynamics and the ants do not. Second, workers from different ant species varied with respect to their dynamics, presenting degrees of predictability as well as stochastic signals. Finally, differences were found among minor and major caste of the same (dimorphic) ant species. Our results underscore the potential of RQA and RPs in the analysis of complex behavioral patterns, as well as in general inferences on animal behavior and other biological phenomena. PMID:29016648

  6. Persistence of pollination mutualisms in the presence of ants.

    PubMed

    Wang, Yuanshi; Wang, Shikun

    2015-01-01

    This paper considers plant-pollinator-ant systems in which the plant-pollinator interaction is mutualistic but ants have both positive and negative effects on plants. The ants also interfere with pollinators by preventing them from accessing plants. While a Beddington-DeAngelis (BD) formula can describe the plant-pollinator interaction, the formula is extended in this paper to characterize the pollination mutualism under the ant interference. Then, a plant-pollinator-ant system with the extended BD functional response is discussed, and global dynamics of the model demonstrate the mechanisms by which pollination mutualism can persist in the presence of ants. When the ant interference is strong, it can result in extinction of pollinators. Moreover, if the ants depend on pollination mutualism for survival, the strong interference could drive pollinators into extinction, which consequently lead to extinction of the ants themselves. When the ant interference is weak, a cooperation between plant-ant and plant-pollinator mutualisms could occur, which promotes survival of both ants and pollinators, especially in the case that ants (respectively, pollinators) cannot survive in the absence of pollinators (respectively, ants). Even when the level of ant interference remains invariant, varying ants' negative effect on plants can result in survival/extinction of both ants and pollinators. Therefore, our results provide an explanation for the persistence of pollination mutualism when there exist ants.

  7. MULTIWAVELENGTH OBSERVATIONS OF 3C 454.3. III. EIGHTEEN MONTHS OF AGILE MONITORING OF THE 'CRAZY DIAMOND'

    SciTech Connect

    Vercellone, S.; Romano, P.; D'Ammando, F.

    2010-03-20

    We report on 18 months of multiwavelength observations of the blazar 3C 454.3 (Crazy Diamond) carried out in the period 2007 July-2009 January. In particular, we show the results of the AGILE campaigns which took place on 2008 May-June, 2008 July-August, and 2008 October-2009 January. During the 2008 May-2009 January period, the source average flux was highly variable, with a clear fading trend toward the end of the period, from an average gamma-ray flux F{sub E>100{sub MeV}} {approx}> 200 x 10{sup -8} photons cm{sup -2} s{sup -1} in 2008 May-June, to F{sub E>100{sub MeV}} {approx} 80 x 10{sup -8} photonsmore » cm{sup -2} s{sup -1} in 2008 October-2009 January. The average gamma-ray spectrum between 100 MeV and 1 GeV can be fit by a simple power law, showing a moderate softening (from GAMMA{sub GRID} {approx} 2.0 to GAMMA{sub GRID} {approx} 2.2) toward the end of the observing campaign. Only 3sigma upper limits can be derived in the 20-60 keV energy band with Super-AGILE, because the source was considerably off-axis during the whole time period. In 2007 July-August and 2008 May-June, 3C 454.3 was monitored by Rossi X-ray Timing Explorer (RXTE). The RXTE/Proportional Counter Array (PCA) light curve in the 3-20 keV energy band shows variability correlated with the gamma-ray one. The RXTE/PCA average flux during the two time periods is F{sub 3-20{sub keV}} = 8.4 x 10{sup -11} erg cm{sup -2} s{sup -1}, and F{sub 3-20{sub keV}} = 4.5 x 10{sup -11} erg cm{sup -2} s{sup -1}, respectively, while the spectrum (a power law with photon index GAMMA{sub PCA} = 1.65 +- 0.02) does not show any significant variability. Consistent results are obtained with the analysis of the RXTE/High-Energy X-Ray Timing Experiment quasi-simultaneous data. We also carried out simultaneous Swift observations during all AGILE campaigns. Swift/XRT detected 3C 454.3 with an observed flux in the 2-10 keV energy band in the range (0.9-7.5) x 10{sup -11} erg cm{sup -2} s{sup -1} and a photon index in

  8. FDTD-ANT User Manual

    NASA Technical Reports Server (NTRS)

    Zimmerman, Martin L.

    1995-01-01

    This manual explains the theory and operation of the finite-difference time domain code FDTD-ANT developed by Analex Corporation at the NASA Lewis Research Center in Cleveland, Ohio. This code can be used for solving electromagnetic problems that are electrically small or medium (on the order of 1 to 50 cubic wavelengths). Calculated parameters include transmission line impedance, relative effective permittivity, antenna input impedance, and far-field patterns in both the time and frequency domains. The maximum problem size may be adjusted according to the computer used. This code has been run on the DEC VAX and 486 PC's and on workstations such as the Sun Sparc and the IBM RS/6000.

  9. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant-plant mutualism.

    PubMed

    Pringle, Elizabeth G

    2014-06-22

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant-plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output.

  10. Differential Recruitment of Camponotus femoratus (Fabricius) Ants in Response to Ant Garden Herbivory.

    PubMed

    Vicente, R E; Dáttilo, W; Izzo, T J

    2014-12-01

    Although several studies have shown that ants can recognize chemical cues from their host plants in ant-plant systems, it is poorly demonstrated in ant gardens (AGs). In this interaction, ant species constantly interact with various epiphyte species. Therefore, it is possible to expect a convergence of chemical signals released by plants that could be acting to ensure that ants are able to recognize and defend epiphyte species frequently associated with AGs. In this study, it was hypothesized that ants recognize and differentiate among chemical stimuli released by AG epiphytes and non-AG epiphytes. We experimentally simulated leaf herbivore damage on three epiphyte species restricted to AGs and a locally abundant understory herb, Piper hispidum, in order to quantify the number of recruited Camponotus femoratus (Fabricius) defenders. When exposed to the AG epiphytes Peperomia macrostachya and Codonanthe uleana leaves, it was observed that the recruitment of C. femoratus workers was, on average, respectively 556% and 246% higher than control. However, the number of ants recruited by the AG epiphyte Markea longiflora or by the non-AG plant did not differ from paper pieces. This indicated that ants could discern between chemicals released by different plants, suggesting that ants can select better plants. These results can be explained by evolutionary process acting on both ants' capability in discerning plants' chemical compounds (innate attraction) or by ants' learning based on the epiphyte frequency in AGs (individual experience). To disentangle an innate behavior, a product of classical coevolutionary process, from an ant's learned behavior, is a complicated but important subject to understand in the evolution of ant-plant mutualisms.

  11. How to be an ant on figs

    NASA Astrophysics Data System (ADS)

    Bain, Anthony; Harrison, Rhett D.; Schatz, Bertrand

    2014-05-01

    Mutualistic interactions are open to exploitation by one or other of the partners and a diversity of other organisms, and hence are best understood as being embedded in a complex network of biotic interactions. Figs participate in an obligate mutualism in that figs are dependent on agaonid fig wasps for pollination and the wasps are dependent on fig ovules for brood sites. Ants are common insect predators and abundant in tropical forests. Ants have been recorded on approximately 11% of fig species, including all six subgenera, and often affect the fig-fig pollinator interaction through their predation of either pollinating and parasitic wasps. On monoecious figs, ants are often associated with hemipterans, whereas in dioecious figs ants predominantly prey on fig wasps. A few fig species are true myrmecophytes, with domatia or food rewards for ants, and in at least one species this is linked to predation of parasitic fig wasps. Ants also play a role in dispersal of fig seeds and may be particularly important for hemi-epiphytic species, which require high quality establishment microsites in the canopy. The intersection between the fig-fig pollinator and ant-plant systems promises to provide fertile ground for understanding mutualistic interactions within the context of complex interaction networks.

  12. Extrafloral nectar fuels ant life in deserts

    PubMed Central

    Aranda-Rickert, Adriana; Diez, Patricia; Marazzi, Brigitte

    2014-01-01

    Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal desert of northwestern Argentina, we surveyed the richness and phenology of EFN plants and their associated ants and examined the patterns in ant–plant interaction networks. We found that 25 ant species and 11 EFN-bearing plant species were linked together through 96 pairs of associations. Plants bearing EFNs were abundant, representing ca. 19 % of the species encountered in transects and 24 % of the plant cover. Most ant species sampled (ca. 77 %) fed on EF nectar. Interactions showed a marked seasonal pattern: EFN secretion was directly related to plant phenology and correlated with the time of highest ant ground activity. Our results reveal that EFN-mediated interactions are ecologically relevant components of deserts, and that EFN-bearing plants are crucial for the survival of desert ant communities. PMID:25381258

  13. Ant-lepidopteran associations along African forest edges

    NASA Astrophysics Data System (ADS)

    Dejean, Alain; Azémar, Frédéric; Libert, Michel; Compin, Arthur; Hérault, Bruno; Orivel, Jérôme; Bouyer, Thierry; Corbara, Bruno

    2017-02-01

    Working along forest edges, we aimed to determine how some caterpillars can co-exist with territorially dominant arboreal ants (TDAAs) in tropical Africa. We recorded caterpillars from 22 lepidopteran species living in the presence of five TDAA species. Among the defoliator and/or nectarivorous caterpillars that live on tree foliage, the Pyralidae and Nymphalidae use their silk to protect themselves from ant attacks. The Notodontidae and lycaenid Polyommatinae and Theclinae live in direct contact with ants; the Theclinae even reward ants with abundant secretions from their Newcomer gland. Lichen feeders (lycaenid; Poritiinae), protected by long bristles, also live among ants. Some lycaenid Miletinae caterpillars feed on ant-attended membracids, including in the shelters where the ants attend them; Lachnocnema caterpillars use their forelegs to obtain trophallaxis from their host ants. Caterpillars from other species live inside weaver ant nests. Those of the genus Euliphyra (Miletinae) feed on ant prey and brood and can obtain trophallaxis, while those from an Eberidae species only prey on host ant eggs. Eublemma albifascia (Erebidae) caterpillars use their thoracic legs to obtain trophallaxis and trophic eggs from ants. Through transfer bioassays of last instars, we noted that herbivorous caterpillars living in contact with ants were always accepted by alien conspecific ants; this is likely due to an intrinsic appeasing odor. Yet, caterpillars living in ant shelters or ant nests probably acquire cues from their host colonies because they were considered aliens and killed. We conclude that co-evolution with ants occurred similarly in the Heterocera and Rhopalocera.

  14. Pheromone disruption of Argentine ant trail integrity.

    PubMed

    Suckling, D M; Peck, R W; Manning, L M; Stringer, L D; Cappadonna, J; El-Sayed, A M

    2008-12-01

    Disruption of Argentine ant trail following and reduced ability to forage (measured by bait location success) was achieved after presentation of an oversupply of trail pheromone, (Z)-9-hexadecenal. Experiments tested single pheromone point sources and dispersion of a formulation in small field plots. Ant walking behavior was recorded and digitized by using video tracking, before and after presentation of trail pheromone. Ants showed changes in three parameters within seconds of treatment: (1) Ants on trails normally showed a unimodal frequency distribution of walking track angles, but this pattern disappeared after presentation of the trail pheromone; (2) ants showed initial high trail integrity on a range of untreated substrates from painted walls to wooden or concrete floors, but this was significantly reduced following presentation of a point source of pheromone; (3) the number of ants in the pheromone-treated area increased over time, as recruitment apparently exceeded departures. To test trail disruption in small outdoor plots, the trail pheromone was formulated with carnuba wax-coated quartz laboratory sand (1 g quartz sand/0.2 g wax/1 mg pheromone). The pheromone formulation, with a half-life of 30 h, was applied by rotary spreader at four rates (0, 2.5, 7.5, and 25 mg pheromone/m(2)) to 1- and 4-m(2) plots in Volcanoes National Park, Hawaii. Ant counts at bait cards in treated plots were significantly reduced compared to controls on the day of treatment, and there was a significant reduction in ant foraging for 2 days. These results show that trail pheromone disruption of Argentine ants is possible, but a much more durable formulation is needed before nest-level impacts can be expected.

  15. Pheromone disruption of Argentine ant trail integrity

    USGS Publications Warehouse

    Suckling, D.M.; Peck, R.W.; Manning, L.M.; Stringer, L.D.; Cappadonna, J.; El-Sayed, A. M.

    2008-01-01

    Disruption of Argentine ant trail following and reduced ability to forage (measured by bait location success) was achieved after presentation of an oversupply of trail pheromone, (Z)-9-hexadecenal. Experiments tested single pheromone point sources and dispersion of a formulation in small field plots. Ant walking behavior was recorded and digitized by using video tracking, before and after presentation of trail pheromone. Ants showed changes in three parameters within seconds of treatment: (1) Ants on trails normally showed a unimodal frequency distribution of walking track angles, but this pattern disappeared after presentation of the trail pheromone; (2) ants showed initial high trail integrity on a range of untreated substrates from painted walls to wooden or concrete floors, but this was significantly reduced following presentation of a point source of pheromone; (3) the number of ants in the pheromone-treated area increased over time, as recruitment apparently exceeded departures. To test trail disruption in small outdoor plots, the trail pheromone was formulated with carnuba wax-coated quartz laboratory sand (1 g quartz sand/0.2 g wax/1 mg pheromone). The pheromone formulation, with a half-life of 30 h, was applied by rotary spreader at four rates (0, 2.5, 7.5, and 25 mg pheromone/m2) to 1- and 4-m2 plots in Volcanoes National Park, Hawaii. Ant counts at bait cards in treated plots were significantly reduced compared to controls on the day of treatment, and there was a significant reduction in ant foraging for 2 days. These results show that trail pheromone disruption of Argentine ants is possible, but a much more durable formulation is needed before nest-level impacts can be expected. ?? 2008 Springer Science+Business Media, LLC.

  16. Multitasking in a plant-ant interaction: how does Acacia myrtifolia manage both ants and pollinators?

    PubMed

    Martínez-Bauer, Angélica E; Martínez, Gerardo Cerón; Murphy, Daniel J; Burd, Martin

    2015-06-01

    Plant associations with protective ants are widespread among angiosperms, but carry the risk that ants will deter pollinators as well as herbivores. Such conflict, and adaptations to ameliorate or prevent the conflict, have been documented in African and neotropical acacias. Ant-acacia associations occur in Australia, but little is known of their ecology. Moreover, recent phylogenetic evidence indicates that Australian acacias are only distantly related to African and American acacias, providing an intercontinental natural experiment in the management of ant-pollinator conflict. We examined four populations of Acacia myrtifolia over a 400-km environmental gradient in southeastern Australia using ant and pollinator exclusion as well as direct observation of ants and pollinators to assess the potential for ant-pollinator conflict to affect seed set. Native bees were the only group of floral visitors whose visitation rates were a significant predictor of fruiting success, although beetles and wasps may play an important role as "insurance" pollinators. We found no increase in pollinator visitation or fruiting success following ant exclusion, even with large sample sizes and effective exclusion. Because ants are facultative visitors to A. myrtifolia plants, their presence may be insufficient to interfere greatly with floral visitors. It is also likely that the morphological location of extrafloral nectaries tends to draw ants away from reproductive parts, although we commonly observed ants on inflorescences, so the spatial separation is not strict. A. myrtifolia appears to maintain a generalized mutualism over a wide geographic range without the need for elaborate adaptations to resolve ant-pollinator conflict.

  17. Structure and formation of ant transportation networks

    PubMed Central

    Latty, Tanya; Ramsch, Kai; Ito, Kentaro; Nakagaki, Toshiyuki; Sumpter, David J. T.; Middendorf, Martin; Beekman, Madeleine

    2011-01-01

    Many biological systems use extensive networks for the transport of resources and information. Ants are no exception. How do biological systems achieve efficient transportation networks in the absence of centralized control and without global knowledge of the environment? Here, we address this question by studying the formation and properties of inter-nest transportation networks in the Argentine ant (Linepithema humile). We find that the formation of inter-nest networks depends on the number of ants involved in the construction process. When the number of ants is sufficient and networks do form, they tend to have short total length but a low level of robustness. These networks are topologically similar to either minimum spanning trees or Steiner networks. The process of network formation involves an initial construction of multiple links followed by a pruning process that reduces the number of trails. Our study thus illuminates the conditions under and the process by which minimal biological transport networks can be constructed. PMID:21288958

  18. Exploration adjustment by ant colonies

    PubMed Central

    2016-01-01

    How do animals in groups organize their work? Division of labour, i.e. the process by which individuals within a group choose which tasks to perform, has been extensively studied in social insects. Variability among individuals within a colony seems to underpin both the decision over which tasks to perform and the amount of effort to invest in a task. Studies have focused mainly on discrete tasks, i.e. tasks with a recognizable end. Here, we study the distribution of effort in nest seeking, in the absence of new nest sites. Hence, this task is open-ended and individuals have to decide when to stop searching, even though the task has not been completed. We show that collective search effort declines when colonies inhabit better homes, as a consequence of a reduction in the number of bouts (exploratory events). Furthermore, we show an increase in bout exploration time and a decrease in bout instantaneous speed for colonies inhabiting better homes. The effect of treatment on bout effort is very small; however, we suggest that the organization of work performed within nest searching is achieved both by a process of self-selection of the most hard-working ants and individual effort adjustment. PMID:26909180

  19. Evidence that insect herbivores are deterred by ant pheromones.

    PubMed Central

    Offenberg, Joachim; Nielsen, Mogens Gissel; MacIntosh, Donald J; Havanon, Sopon; Aksornkoae, Sanit

    2004-01-01

    It is well documented that ants can protect plants against insect herbivores, but the underlying mechanisms remain almost undocumented. We propose and test the pheromone avoidance hypothesis--an indirect mechanism where insect herbivores are repelled not only by ants but also by ant pheromones. Herbivores subjected to ant predation will experience a selective advantage if they evolve mechanisms enabling them to avoid feeding within ant territories. Such a mechanism could be based on the ability to detect and evade ant pheromones. Field observations and data from the literature showed that the ant Oecophylla smaragdina distributes persistent pheromones throughout its territory. In addition, a laboratory test showed that the beetle Rhyparida wallacei, which this ant preys on, was reluctant to feed on leaves sampled within ant territories compared with leaves sampled outside territories. Thus, this study provides an example of an ant-herbivore system conforming to the pheromone avoidance hypothesis. PMID:15801596

  20. Toxic industrial deposit remediation by ant activity

    NASA Astrophysics Data System (ADS)

    Jilkova, Veronika; Frouz, Jan

    2016-04-01

    Toxic industrial deposits are often contaminated by heavy metals and the substrates have low pH values. In such systems, soil development is thus slowed down by high toxicity and acidic conditions which are unfavourable to soil fauna. Ants (Hymenoptera, Formicidae) are considered tolerant to heavy metal pollution and are known to increase organic matter content and microbial activity in their nests. Here, we focused on soil remediation caused by three ant species (Formica sanguinea, Lasius niger, and Tetramorium sp.) in an ore-washery sedimentation basin near Chvaletice (Czech Republic). Soil samples were taken from the centre of ant nests and from the nest surroundings (>3 m from nests). Samples were then analyzed for microbial activity and biomass and contents of organic matter and nutrients. As a result, ant species that most influenced soil properties was F. sanguinea as there were higher microbial activity and total nitrogen and ammonia contents in ant nests than in the surrounding soil. We expected such a result because F. sanguinea builds conspicuous large nests and is a carnivorous species that brings substantial amounts of nitrogen in insect prey to their nests. Effects of the other two ant species might be lower because of smaller nests and different feeding habits as they rely mainly on honeydew from aphids or on plant seeds that do not contain much nutrients.

  1. Fire ants perpetually rebuild sinking towers.

    PubMed

    Phonekeo, Sulisay; Mlot, Nathan; Monaenkova, Daria; Hu, David L; Tovey, Craig

    2017-07-01

    In the aftermath of a flood, fire ants, Solenopsis invicta , cluster into temporary encampments. The encampments can contain hundreds of thousands of ants and reach over 30 ants high. How do ants build such tall structures without being crushed? In this combined experimental and theoretical study, we investigate the shape and rate of construction of ant towers around a central support. The towers are bell shaped, consistent with towers of constant strength such as the Eiffel tower, where each element bears an equal load. However, unlike the Eiffel tower, the ant tower is built through a process of trial and error, whereby failed portions avalanche until the final shape emerges. High-speed and novel X-ray videography reveal that the tower constantly sinks and is rebuilt, reminiscent of large multicellular systems such as human skin. We combine the behavioural rules that produce rafts on water with measurements of adhesion and attachment strength to model the rate of growth of the tower. The model correctly predicts that the growth rate decreases as the support diameter increases. This work may inspire the design of synthetic swarms capable of building in vertical layers.

  2. Fire ants perpetually rebuild sinking towers

    NASA Astrophysics Data System (ADS)

    Phonekeo, Sulisay; Mlot, Nathan; Monaenkova, Daria; Hu, David L.; Tovey, Craig

    2017-07-01

    In the aftermath of a flood, fire ants, Solenopsis invicta, cluster into temporary encampments. The encampments can contain hundreds of thousands of ants and reach over 30 ants high. How do ants build such tall structures without being crushed? In this combined experimental and theoretical study, we investigate the shape and rate of construction of ant towers around a central support. The towers are bell shaped, consistent with towers of constant strength such as the Eiffel tower, where each element bears an equal load. However, unlike the Eiffel tower, the ant tower is built through a process of trial and error, whereby failed portions avalanche until the final shape emerges. High-speed and novel X-ray videography reveal that the tower constantly sinks and is rebuilt, reminiscent of large multicellular systems such as human skin. We combine the behavioural rules that produce rafts on water with measurements of adhesion and attachment strength to model the rate of growth of the tower. The model correctly predicts that the growth rate decreases as the support diameter increases. This work may inspire the design of synthetic swarms capable of building in vertical layers.

  3. Congestion and communication in confined ant traffic

    NASA Astrophysics Data System (ADS)

    Gravish, Nick; Gold, Gregory; Zangwill, Andrew; Goodisman, Michael A. D.; Goldman, Daniel I.

    2014-03-01

    Many social animals move and communicate within confined spaces. In subterranean fire ants Solenopsis invicta, mobility within crowded nest tunnels is important for resource and information transport. Within confined tunnels, communication and traffic flow are at odds: trafficking ants communicate through tactile interactions while stopped, yet ants that stop to communicate impose physical obstacles on the traffic. We monitor the bi-directional flow of fire ant workers in laboratory tunnels of varied diameter D. The persistence time of communicating ant aggregations, τ, increases approximately linearly with the number of participating ants, n. The sensitivity of traffic flow increases as D decreases and diverges at a minimum diameter, Dc. A cellular automata model incorporating minimal traffic features--excluded volume and communication duration--reproduces features of the experiment. From the model we identify a competition between information transfer and the need to maintain jam-free traffic flow. We show that by balancing information transfer and traffic flow demands, an optimum group strategy exists which maximizes information throughput. We acknowledge funding from NSF PoLS #0957659 and #PHY-1205878.

  4. Fire ants perpetually rebuild sinking towers

    PubMed Central

    Phonekeo, Sulisay; Mlot, Nathan; Monaenkova, Daria; Tovey, Craig

    2017-01-01

    In the aftermath of a flood, fire ants, Solenopsis invicta, cluster into temporary encampments. The encampments can contain hundreds of thousands of ants and reach over 30 ants high. How do ants build such tall structures without being crushed? In this combined experimental and theoretical study, we investigate the shape and rate of construction of ant towers around a central support. The towers are bell shaped, consistent with towers of constant strength such as the Eiffel tower, where each element bears an equal load. However, unlike the Eiffel tower, the ant tower is built through a process of trial and error, whereby failed portions avalanche until the final shape emerges. High-speed and novel X-ray videography reveal that the tower constantly sinks and is rebuilt, reminiscent of large multicellular systems such as human skin. We combine the behavioural rules that produce rafts on water with measurements of adhesion and attachment strength to model the rate of growth of the tower. The model correctly predicts that the growth rate decreases as the support diameter increases. This work may inspire the design of synthetic swarms capable of building in vertical layers. PMID:28791170

  5. Detection and dispersal of explosives by ants

    NASA Astrophysics Data System (ADS)

    McFee, John E.; Achal, Steve; Faust, Anthony A.; Puckrin, Eldon; House, Andrew; Reynolds, Damon; McDougall, William; Asquini, Adam

    2009-05-01

    The ability of animals to detect explosives is well documented. Mammalian systems, insects and even single celled organisms have all been studied and in a few cases employed to detect explosives. This paper will describe the potential ability of ants to detect, disperse and possibly neutralize bulk explosives. In spring 2008 a team of DRDC and Itres scientists conducted experiments on detecting surface-laid and buried landmines, improvised explosive devices (IEDs) and their components. Measurements were made using state-of-the-art short wave and thermal infrared hyperspectral imagers mounted on a personnel lift. During one of the early morning measurement sessions, a wispy, long linear trail was seen to emanate several meters from piles of explosives that were situated on the ground. Upon close visual inspection, it was observed that ants had found the piles of explosives and were carrying it to their ant hill, a distance of almost 20 meters from the piles. Initial analysis of the hyperspectral images clearly revealed the trail to the ant hill of explosives, despite being present in quantities not visible to the unaided eye. This paper details these observations and discusses them in the context of landmine and IED detection and neutralization. Possible reasons for such behaviour are presented. A number of questions regarding the behaviour, many pertinent to the use of ants in a counter-landmine/IED role, are presented and possible methods of answering them are discussed. Anecdotal evidence from deminers of detection and destruction of explosives by ants are presented.

  6. How Ants Use Vision When Homing Backward.

    PubMed

    Schwarz, Sebastian; Mangan, Michael; Zeil, Jochen; Webb, Barbara; Wystrach, Antoine

    2017-02-06

    Ants can navigate over long distances between their nest and food sites using visual cues [1, 2]. Recent studies show that this capacity is undiminished when walking backward while dragging a heavy food item [3-5]. This challenges the idea that ants use egocentric visual memories of the scene for guidance [1, 2, 6]. Can ants use their visual memories of the terrestrial cues when going backward? Our results suggest that ants do not adjust their direction of travel based on the perceived scene while going backward. Instead, they maintain a straight direction using their celestial compass. This direction can be dictated by their path integrator [5] but can also be set using terrestrial visual cues after a forward peek. If the food item is too heavy to enable body rotations, ants moving backward drop their food on occasion, rotate and walk a few steps forward, return to the food, and drag it backward in a now-corrected direction defined by terrestrial cues. Furthermore, we show that ants can maintain their direction of travel independently of their body orientation. It thus appears that egocentric retinal alignment is required for visual scene recognition, but ants can translate this acquired directional information into a holonomic frame of reference, which enables them to decouple their travel direction from their body orientation and hence navigate backward. This reveals substantial flexibility and communication between different types of navigational information: from terrestrial to celestial cues and from egocentric to holonomic directional memories. VIDEO ABSTRACT. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  7. The descent of ant: field-measured performance of gliding ants.

    PubMed

    Munk, Yonatan; Yanoviak, Stephen P; Koehl, M A R; Dudley, Robert

    2015-05-01

    Gliding ants avoid predatory attacks and potentially mortal consequences of dislodgement from rainforest canopy substrates by directing their aerial descent towards nearby tree trunks. The ecologically relevant measure of performance for gliding ants is the ratio of net horizontal to vertical distance traveled over the course of a gliding trajectory, or glide index. To study variation in glide index, we measured three-dimensional trajectories of Cephalotes atratus ants gliding in natural rainforest habitats. We determined that righting phase duration, glide angle, and path directness all significantly influence variation in glide index. Unsuccessful landing attempts result in the ant bouncing off its target and being forced to make a second landing attempt. Our results indicate that ants are not passive gliders and that they exert active control over the aerodynamic forces they experience during their descent, despite their apparent lack of specialized control surfaces. © 2015. Published by The Company of Biologists Ltd.

  8. Fossil evidence for the early ant evolution

    NASA Astrophysics Data System (ADS)

    Perrichot, Vincent; Lacau, Sébastien; Néraudeau, Didier; Nel, André

    2008-02-01

    Ants are one of the most studied insects in the world; and the literature devoted to their origin and evolution, systematics, ecology, or interactions with plants, fungi and other organisms is prolific. However, no consensus yet exists on the age estimate of the first Formicidae or on the origin of their eusociality. We review the fossil and biogeographical record of all known Cretaceous ants. We discuss the possible origin of the Formicidae with emphasis on the most primitive subfamily Sphecomyrminae according to its distribution and the Early Cretaceous palaeogeography. And we review the evidence of true castes and eusociality of the early ants regarding their morphological features and their manner of preservation in amber. The mid-Cretaceous amber forest from south-western France where some of the oldest known ants lived, corresponded to a moist tropical forest close to the shore with a dominance of gymnosperm trees but where angiosperms (flowering plants) were already diversified. This palaeoenvironmental reconstruction supports an initial radiation of ants in forest ground litter coincident with the rise of angiosperms, as recently proposed as an ecological explanation for their origin and successful evolution.

  9. Desert ants learn vibration and magnetic landmarks.

    PubMed

    Buehlmann, Cornelia; Hansson, Bill S; Knaden, Markus

    2012-01-01

    The desert ants Cataglyphis navigate not only by path integration but also by using visual and olfactory landmarks to pinpoint the nest entrance. Here we show that Cataglyphis noda can additionally use magnetic and vibrational landmarks as nest-defining cues. The magnetic field may typically provide directional rather than positional information, and vibrational signals so far have been shown to be involved in social behavior. Thus it remains questionable if magnetic and vibration landmarks are usually provided by the ants' habitat as nest-defining cues. However, our results point to the flexibility of the ants' navigational system, which even makes use of cues that are probably most often sensed in a different context.

  10. Production scheduling with ant colony optimization

    NASA Astrophysics Data System (ADS)

    Chernigovskiy, A. S.; Kapulin, D. V.; Noskova, E. E.; Yamskikh, T. N.; Tsarev, R. Yu

    2017-10-01

    The optimum solution of the production scheduling problem for manufacturing processes at an enterprise is crucial as it allows one to obtain the required amount of production within a specified time frame. Optimum production schedule can be found using a variety of optimization algorithms or scheduling algorithms. Ant colony optimization is one of well-known techniques to solve the global multi-objective optimization problem. In the article, the authors present a solution of the production scheduling problem by means of an ant colony optimization algorithm. A case study of the algorithm efficiency estimated against some others production scheduling algorithms is presented. Advantages of the ant colony optimization algorithm and its beneficial effect on the manufacturing process are provided.

  11. Detection of mitochondrial COII DNA sequences in ant guts as a method for assessing termite predation by ants.

    PubMed

    Fayle, Tom M; Scholtz, Olivia; Dumbrell, Alex J; Russell, Stephen; Segar, Simon T; Eggleton, Paul

    2015-01-01

    Termites and ants contribute more to animal biomass in tropical rain forests than any other single group and perform vital ecosystem functions. Although ants prey on termites, at the community level the linkage between these groups is poorly understood. Thus, assessing the distribution and specificity of ant termitophagy is of considerable interest. We describe an approach for quantifying ant-termite food webs by sequencing termite DNA (cytochrome c oxidase subunit II, COII) from ant guts and apply this to a soil-dwelling ant community from tropical rain forest in Gabon. We extracted DNA from 215 ants from 15 species. Of these, 17.2 % of individuals had termite DNA in their guts, with BLAST analysis confirming the identity of 34.1 % of these termites to family level or better. Although ant species varied in detection of termite DNA, ranging from 63 % (5/7; Camponotus sp. 1) to 0 % (0/7; Ponera sp. 1), there was no evidence (with small sample sizes) for heterogeneity in termite consumption across ant taxa, and no evidence for species-specific ant-termite predation. In all three ant species with identifiable termite DNA in multiple individuals, multiple termite species were represented. Furthermore, the two termite species that were detected on multiple occasions in ant guts were in both cases found in multiple ant species, suggesting that ant-termite food webs are not strongly compartmentalised. However, two ant species were found to consume only Anoplotermes-group termites, indicating possible predatory specialisation at a higher taxonomic level. Using a laboratory feeding test, we were able to detect termite COII sequences in ant guts up to 2 h after feeding, indicating that our method only detects recent feeding events. Our data provide tentative support for the hypothesis that unspecialised termite predation by ants is widespread and highlight the use of molecular approaches for future studies of ant-termite food webs.

  12. An ants-eye view of an ant-plant protection mutualism

    PubMed Central

    Lanan, M. C.; Bronstein, J. L.

    2013-01-01

    Ant protection of extrafloral nectar-secreting plants (EFN plants) is a common form of mutualism found in most habitats around the world. However, very few studies have considered these mutualisms from the ant, rather than the plant, perspective. In particular, a whole-colony perspective that takes into account the spatial structure and nest arrangement of the ant colonies that visit these plants has been lacking, obscuring when and how colony-level foraging decisions might affect tending rates on individual plants. Here, we experimentally demonstrate that recruitment of Crematogaster opuntiae (Buren) ant workers to the extrafloral nectar-secreting cactus Ferocactus wislizeni (Englem) is not independent between plants up to 5m apart. Colony territories of C. opuntiae are large, covering areas of up to 5000m2, and workers visit between five and thirty-four extrafloral nectar-secreting barrel cacti within the territories. These ants are highly polydomous, with up to twenty nest entrances dispersed throughout the territory and interconnected by trail networks. Our study demonstrates that worker recruitment is not independent within large polydomous ant colonies, highlighting the importance of considering colonies rather than individual workers as the relevant study unit within ant/plant protection mutualisms PMID:23515612

  13. Wolbachia transmission dynamics in Formica wood ants

    PubMed Central

    2008-01-01

    Background The role of Wolbachia endosymbionts in shaping the mitochondrial diversity of their arthropod host depends on the effects they have on host reproduction and on the mode of transmission of the bacteria. We have compared the sequence diversity of wsp (Wolbachia surface protein gene) and the host mtDNA in a group of Formica ant species that have diverged approximately 0.5 million years ago (MYA). The aim was to study the relationship of Wolbachia and its ant hosts in terms of vertical and horizontal transmission of the bacteria. Results All studied ant species were doubly infected with two Wolbachia strains (wFex1 and wFex4) all over their geographical distribution area in Eurasia. The most common haplotypes of these strains were identical with strains previously described from a more distantly related Formica ant, with an estimated divergence time of 3.5 – 4 MYA. Some strain haplotypes were associated to the same or closely related mtDNA haplotypes as expected under vertical transmission. However, in several cases the wsp haplotypes coexisted with distant mtDNA haplotypes, a pattern which is more compatible with horizontal transmission of the bacteria. Conclusion Two lines of evidence suggest that the sharing of Wolbachia strains by all F. rufa species is rather due to horizontal than vertical transmission. First, the fact that endosymbiont strains identical to those of F. rufa ants have been found in another species that diverged 3.5–4 MYA strongly suggests that horizontal transfer can and does occur between Formica ants. Second, the frequent sharing of identical Wolbachia strains by distant mitochondrial lineages within the F. rufa group further shows that horizontal transmission has occurred repeatedly. Nevertheless, our dataset also provides some evidence for longer-term persistence of infection, indicating that Wolbachia infection within this host clade has been shaped by both horizontal and vertical transmission of symbionts. The fact that all

  14. Image Edge Tracking via Ant Colony Optimization

    NASA Astrophysics Data System (ADS)

    Li, Ruowei; Wu, Hongkun; Liu, Shilong; Rahman, M. A.; Liu, Sanchi; Kwok, Ngai Ming

    2018-04-01

    A good edge plot should use continuous thin lines to describe the complete contour of the captured object. However, the detection of weak edges is a challenging task because of the associated low pixel intensities. Ant Colony Optimization (ACO) has been employed by many researchers to address this problem. The algorithm is a meta-heuristic method developed by mimicking the natural behaviour of ants. It uses iterative searches to find the optimal solution that cannot be found via traditional optimization approaches. In this work, ACO is employed to track and repair broken edges obtained via conventional Sobel edge detector to produced a result with more connected edges.

  15. Exploring with PAM: Prospecting ANTS Missions for Solar System Surveys

    NASA Astrophysics Data System (ADS)

    Clark, P. E.; Rilee, M. L.; Curtis, S. A.

    2003-03-01

    ANTS (Autonomous Nano Technology Swarm of hundreds of picoclass autonomous spacecraft) have many applications. A version designed for surveying and the resource potential of the asteroid belt, called PAM (Prospecting ANTS Mission), is examined here.

  16. Variation in Extrafloral Nectary Productivity Influences the Ant Foraging

    PubMed Central

    2017-01-01

    Extrafloral nectar is the main food source offered by plants to predatory ants in most land environments. Although many studies have demonstrated the importance of extrafloral nectaries (EFNs) to plant defense against herbivores, the influence of EFNs secretory activity pattern on predatory ants remains yet not fully understood. Here, we verified the relation between the extrafloral nectar production of a plant community in Cerrado in different times of the day, and its attractiveness to ants. The extrafloral nectaries (EFNs) of seven plant species showed higher productivity overnight. Ant abundance was higher in times of large extrafloral nectar production, however, there was no positive relation between ant richness on plants and EFNs productivity. There was temporal resource partitioning among ant species, and it indicates strong resource competition. The nectar productivity varied among plant species and time of the day, and it influenced the visitation patterns of ants. Therefore, EFNs are a key ant-plant interaction driver in the studied system. PMID:28046069

  17. A global database of ant species abundances

    USGS Publications Warehouse

    Gibb, Heloise; Dunn, Rob R.; Sanders, Nathan J.; Grossman, Blair F.; Photakis, Manoli; Abril, Silvia; Agosti, Donat; Andersen, Alan N.; Angulo, Elena; Armbrecht, Ingre; Arnan, Xavier; Baccaro, Fabricio B.; Bishop, Tom R.; Boulay, Raphael; Bruhl, Carsten; Castracani, Cristina; Cerda, Xim; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A.; Ellison, Aaron M.; Enriquez, Martha L.; Fayle, Tom M.; Feener Jr., Donald H.; Fisher, Brian L.; Fisher, Robert N.; Fitpatrick, Matthew C.; Gomez, Cristanto; Gotelli, Nicholas J.; Gove, Aaron; Grasso, Donato A.; Groc, Sarah; Guenard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin; Janda, Milan; Jenkins, Clinton; Kaspari, Michael; Klimes, Petr; Lach, Lori; Laeger, Thomas; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Luke, Sarah H.; Majer, Jonathan; McGlynn, Terrence P.; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Pacheco, Renata; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M.; Resasco, Julian; Retana, Javier; Silva, Rogerio R.; Sorger, Magdalena D.; Souza, Jorge; Suarez, Andrew V.; Tista, Melanie; Vasconcelos, Heraldo L.; Vonshak, Merav; Weiser, Michael D.; Yates, Michelle; Parr, Catherine L.

    2017-01-01

    What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51,388 ant abundance and occurrence records of more than 2693 species and 7953 morphospecies from local assemblages collected at 4212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type and degree of disturbance. The aim of compiling this dataset was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardised methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing dataset.

  18. Operant conditioning in the ant Myrmica sabuleti.

    PubMed

    Cammaerts, M C

    2004-11-30

    Operant conditioning could be obtained in the ant Myrmica sabuleti by presenting to the workers, during a six-day period, an apparatus containing either sugared water or meat as a reward. The conditioning obtained using sugared water as a reward was short lasting. A reconditioning was more persistent and lasted four hours. The ants' response was very precise, since they exhibited it only in front of an apparatus identical to that used during the training phase. Operant conditioning obtained using meat as a reward was more pronounced than that obtained by using sugared water, probably because meat is more valuable as a reward than sugar for the species studied, which is essentially a carnivorous one. Such a conditioning was rather persistent. Indeed, a first operant conditioning obtained by using meat as a reward could still be detected after seven hours, and a reconditioning was still significant after eight hours. One day after this eight-hour period without rewarding the ants, the response was higher again and a further day later, it was still significant. Since the operant conditioning is easy to perform and quantify and since the ants' response is very precise, such a conditioning can be used for further studying M. sabuleti workers' visual perception.

  19. Water surface locomotion in tropical canopy ants.

    PubMed

    Yanoviak, S P; Frederick, D N

    2014-06-15

    Upon falling onto the water surface, most terrestrial arthropods helplessly struggle and are quickly eaten by aquatic predators. Exceptions to this outcome mostly occur among riparian taxa that escape by walking or swimming at the water surface. Here we document sustained, directional, neustonic locomotion (i.e. surface swimming) in tropical arboreal ants. We dropped 35 species of ants into natural and artificial aquatic settings in Peru and Panama to assess their swimming ability. Ten species showed directed surface swimming at speeds >3 body lengths s(-1), with some swimming at absolute speeds >10 cm s(-1). Ten other species exhibited partial swimming ability characterized by relatively slow but directed movement. The remaining species showed no locomotory control at the surface. The phylogenetic distribution of swimming among ant genera indicates parallel evolution and a trend toward negative association with directed aerial descent behavior. Experiments with workers of Odontomachus bauri showed that they escape from the water by directing their swimming toward dark emergent objects (i.e. skototaxis). Analyses of high-speed video images indicate that Pachycondyla spp. and O. bauri use a modified alternating tripod gait when swimming; they generate thrust at the water surface via synchronized treading and rowing motions of the contralateral fore and mid legs, respectively, while the hind legs provide roll stability. These results expand the list of facultatively neustonic terrestrial taxa to include various species of tropical arboreal ants. © 2014. Published by The Company of Biologists Ltd.

  20. Invasive ants influence native lizard populations

    USDA-ARS?s Scientific Manuscript database

    The red imported fire ant (Solenopsis invicta; hereafter RIFA) is an invasive predator found on four continents, including South America, North America, Australia, and Asia. RIFAs are implicated in the decline of native invertebrates and vertebrates throughout their invaded range. We used the easter...

  1. Caste-specific tyramides from Myrmicine ants

    Treesearch

    T.H. Jones; H.M. Garrafo; T.F. Spande; N.R. Andriamaharavo; J.S.T. Gorman; A.J. Snyder; A.W. Jeter; J.A. Torres; John W. Daly

    2010-01-01

    Analysis of the extracts of male ants of Monomorium minimum and Monomorium ebeninum by GC-MS and GC-FTIR revealed the presence of tyramides 2 and 4c, for which the structures were established by comparison with synthetic samples. These compounds and their analogues 1 and 3 were also found in males of other Monomorium species, males of Myrmicaria opaciventris, and males...

  2. A global database of ant species abundances.

    PubMed

    Gibb, Heloise; Dunn, Rob R; Sanders, Nathan J; Grossman, Blair F; Photakis, Manoli; Abril, Silvia; Agosti, Donat; Andersen, Alan N; Angulo, Elena; Armbrecht, Inge; Arnan, Xavier; Baccaro, Fabricio B; Bishop, Tom R; Boulay, Raphaël; Brühl, Carsten; Castracani, Cristina; Cerda, Xim; Del Toro, Israel; Delsinne, Thibaut; Diaz, Mireia; Donoso, David A; Ellison, Aaron M; Enriquez, Martha L; Fayle, Tom M; Feener, Donald H; Fisher, Brian L; Fisher, Robert N; Fitzpatrick, Matthew C; Gómez, Crisanto; Gotelli, Nicholas J; Gove, Aaron; Grasso, Donato A; Groc, Sarah; Guenard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin; Janda, Milan; Jenkins, Clinton; Kaspari, Michael; Klimes, Petr; Lach, Lori; Laeger, Thomas; Lattke, John; Leponce, Maurice; Lessard, Jean-Philippe; Longino, John; Lucky, Andrea; Luke, Sarah H; Majer, Jonathan; McGlynn, Terrence P; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Pacheco, Renata; Paknia, Omid; Pearce-Duvet, Jessica; Pfeiffer, Martin; Philpott, Stacy M; Resasco, Julian; Retana, Javier; Silva, Rogerio R; Sorger, Magdalena D; Souza, Jorge; Suarez, Andrew; Tista, Melanie; Vasconcelos, Heraldo L; Vonshak, Merav; Weiser, Michael D; Yates, Michelle; Parr, Catherine L

    2017-03-01

    What forces structure ecological assemblages? A key limitation to general insights about assemblage structure is the availability of data that are collected at a small spatial grain (local assemblages) and a large spatial extent (global coverage). Here, we present published and unpublished data from 51 ,388 ant abundance and occurrence records of more than 2,693 species and 7,953 morphospecies from local assemblages collected at 4,212 locations around the world. Ants were selected because they are diverse and abundant globally, comprise a large fraction of animal biomass in most terrestrial communities, and are key contributors to a range of ecosystem functions. Data were collected between 1949 and 2014, and include, for each geo-referenced sampling site, both the identity of the ants collected and details of sampling design, habitat type, and degree of disturbance. The aim of compiling this data set was to provide comprehensive species abundance data in order to test relationships between assemblage structure and environmental and biogeographic factors. Data were collected using a variety of standardized methods, such as pitfall and Winkler traps, and will be valuable for studies investigating large-scale forces structuring local assemblages. Understanding such relationships is particularly critical under current rates of global change. We encourage authors holding additional data on systematically collected ant assemblages, especially those in dry and cold, and remote areas, to contact us and contribute their data to this growing data set. © 2016 by the Ecological Society of America.

  3. Extreme Morphogenesis and Ecological Specialization among Cretaceous Basal Ants.

    PubMed

    Perrichot, Vincent; Wang, Bo; Engel, Michael S

    2016-06-06

    Ants comprise one lineage of the triumvirate of eusocial insects and experienced their early diversification within the Cretaceous [1-9]. Their ecological success is generally attributed to their remarkable social behavior. Not all ants cooperate in social hunting, however, and some of the most effective predatory ants are solitary hunters with powerful trap jaws [10]. Recent evolutionary studies predict that the early branching lineages of extant ants formed small colonies of ground-dwelling, solitary specialist predators [2, 5, 7, 11, 12], while some Cretaceous fossils suggest group recruitment and socially advanced behavior among stem-group ants [9]. We describe a trap-jaw ant from 99 million-year-old Burmese amber with head structures that presumably functioned as a highly specialized trap for large-bodied prey. These are a cephalic horn resulting from an extreme modification of the clypeus hitherto unseen among living and extinct ants and scythe-like mandibles that extend high above the head, both demonstrating the presence of exaggerated morphogenesis early among stem-group ants. The new ant belongs to the Haidomyrmecini, possibly the earliest ant lineage [9], and together these trap-jaw ants suggest that at least some of the earliest Formicidae were solitary specialist predators. With their peculiar adaptations, haidomyrmecines had a refined ecology shortly following the advent of ants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. 9 CFR 354.121 - Ante-mortem inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... he may issue from time to time, be made of rabbits on the day of slaughter in any official plant... INSPECTION AND CERTIFICATION VOLUNTARY INSPECTION OF RABBITS AND EDIBLE PRODUCTS THEREOF Inspection Procedures; Ante-Mortem Inspections § 354.121 Ante-mortem inspection. An ante-mortem inspection of rabbits...

  5. 9 CFR 354.121 - Ante-mortem inspection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... he may issue from time to time, be made of rabbits on the day of slaughter in any official plant... INSPECTION AND CERTIFICATION VOLUNTARY INSPECTION OF RABBITS AND EDIBLE PRODUCTS THEREOF Inspection Procedures; Ante-Mortem Inspections § 354.121 Ante-mortem inspection. An ante-mortem inspection of rabbits...

  6. Biogeography of mutualistic fungi cultivated by leafcutter ants

    USDA-ARS?s Scientific Manuscript database

    Leafcutter ants propagate co-evolving fungi for food. The nearly 50 species of leafcutter ants (Atta, Acromyrmex) range from Argentina to the USA, with the greatest species diversity in southern South America. We elucidate the biogeography of fungi cultivated by leafcutter ants using DNA-sequence an...

  7. Niches and coexistence of ant communities in Puerto Rico

    Treesearch

    J.A. Torres

    1984-01-01

    I studied ant coexistence in adjacent areas of upland tropical forest, grassland, and agricultural land in San Lorenzo, Puerto Rico. Data on food utilization, daily activity, nesting sites, microhabitat utilization and interspecific aggression were collected. Ants' tolerance to 45 degree C was determined in the laboratory. Agricultural and grassland ants eat grain...

  8. Dynamics of an ant-plant-pollinator model

    NASA Astrophysics Data System (ADS)

    Wang, Yuanshi; DeAngelis, Donald L.; Nathaniel Holland, J.

    2015-03-01

    In this paper, we consider plant-pollinator-ant systems in which plant-pollinator interaction and plant-ant interaction are both mutualistic, but there also exists interference of pollinators by ants. The plant-pollinator interaction can be described by a Beddington-DeAngelis formula, so we extend the formula to characterize plant-pollinator mutualisms, including the interference by ants, and form a plant-pollinator-ant model. Using dynamical systems theory, we show uniform persistence of the model. Moreover, we demonstrate conditions under which boundary equilibria are globally asymptotically stable. The dynamics exhibit mechanisms by which the three species could coexist when ants interfere with pollinators. We define a threshold in ant interference. When ant interference is strong, it can drive plant-pollinator mutualisms to extinction. Furthermore, if the ants depend on pollination mutualism for their persistence, then sufficiently strong ant interference could lead to their own extinction as well. Yet, when ant interference is weak, plant-ant and plant-pollinator mutualisms can promote the persistence of one another.

  9. Foraging Distance of the Argentine Ant in California Vineyards.

    PubMed

    Hogg, Brian N; Nelson, Erik H; Hagler, James R; Daane, Kent M

    2018-04-02

    Argentine ants, Linepithema humile (Mayr) (Hymenoptera: Formicidae), form mutualisms with hemipteran pests in crop systems. In vineyards, they feed on honeydew produced by mealybugs and soft scales, which they tend and protect from natural enemies. Few options for controlling Argentine ants are available; one of the more effective approaches is to use liquid baits containing a low dose of an insecticide. Knowledge of ant foraging patterns is required to estimate how many bait stations to deploy per unit area. To measure how far ants move liquid bait in vineyards, we placed bait stations containing sugar water and a protein marker in plots for 6 d, and then collected ants along transects extending away from bait stations. The ants moved an average of 16.08 m and 12.21 m from bait stations in the first and second years of the study, respectively. Marked ants were found up to 63 m from bait stations; however, proportions of marked ants decreased exponentially as distance from the bait station increased. Results indicate that Argentine ants generally forage at distances <36 m in California vineyards, thus suggesting that insecticide bait stations must be deployed at intervals of 36 m or less to control ants. We found no effect of insecticide on distances that ants moved the liquid bait, but this may have been because bait station densities were too low to affect the high numbers of Argentine ants that were present at the study sites.

  10. Model Specification Searches Using Ant Colony Optimization Algorithms

    ERIC Educational Resources Information Center

    Marcoulides, George A.; Drezner, Zvi

    2003-01-01

    Ant colony optimization is a recently proposed heuristic procedure inspired by the behavior of real ants. This article applies the procedure to model specification searches in structural equation modeling and reports the results. The results demonstrate the capabilities of ant colony optimization algorithms for conducting automated searches.

  11. Ex Ante Research Explored: Numbers, Types and Use of Ex Ante Policy Studies by the Dutch Government

    ERIC Educational Resources Information Center

    Haarhuis, Carolien Maria Klein; Smit, Monika

    2017-01-01

    Ex ante research can contribute to evidence-informed policies. In this article, we explore numbers and types of ex ante studies as well as their use. First, we took stock of a potentially wide range of ex ante studies published by the Dutch government between 2005 and 2011, applying a systematic approach. Though unevenly distributed across…

  12. Dead ant walking: a myrmecophilous beetle predator uses parasitoid host location cues to selectively prey on parasitized ants.

    PubMed

    Mathis, Kaitlyn A; Tsutsui, Neil D

    2016-08-17

    Myrmecophiles (i.e. organisms that associate with ants) use a variety of ecological niches and employ different strategies to survive encounters with ants. Because ants are typically excellent defenders, myrmecophiles may choose moments of weakness to take advantage of their ant associates. This hypothesis was studied in the rove beetle, Myrmedonota xipe, which associates with Azteca sericeasur ants in the presence of parasitoid flies. A combination of laboratory and field experiments show that M. xipe beetles selectively locate and prey upon parasitized ants. These parasitized ants are less aggressive towards beetles than healthy ants, allowing beetles to eat the parasitized ants alive without interruption. Moreover, behavioural assays and chemical analysis reveal that M. xipe are attracted to the ant's alarm pheromone, the same secretion used by the phorid fly parasitoids in host location. This strategy allows beetles access to an abundant but otherwise inaccessible resource, as A. sericeasur ants are typically highly aggressive. These results are the first, to our knowledge, to demonstrate a predator sharing cues with a parasitoid to gain access to an otherwise unavailable prey item. Furthermore, this work highlights the importance of studying ant-myrmecophile interactions beyond just their pairwise context. © 2016 The Author(s).

  13. Ant species confer different partner benefits on two neotropical myrmecophytes.

    PubMed

    Frederickson, Megan E

    2005-04-01

    The dynamics of mutualistic interactions involving more than a single pair of species depend on the relative costs and benefits of interaction among alternative partners. The neotropical myrmecophytes Cordia nodosa and Duroia hirsuta associate with several species of obligately symbiotic ants. I compared the ant partners of Cordia and Duroia with respect to two benefits known to be important in ant-myrmecophyte interactions: protection against herbivores provided by ants, and protection against encroaching vegetation provided by ants. Azteca spp., Myrmelachista schumanni, and Allomerus octoarticulatus demerarae ants all provide the leaves of Cordia and Duroia some protection against herbivores. However, Azteca and Allomerus provide more protection than does Myrmelachista to the leaves of their host plants. Although Allomerus protects the leaves of its hosts, plants occupied by Allomerus suffer more attacks by herbivores to their stems than do plants occupied by other ants. Relative to Azteca or Allomerus, Myrmelachista ants provide better protection against encroaching vegetation, increasing canopy openness over their host plants. These differences in benefits among the ant partners of Cordia and Duroia are reflected in the effect of each ant species on host plant size, growth rate, and reproduction. The results of this study show how mutualistic ant partners can differ with respect to both the magnitude and type of benefits they provide to the same species of myrmecophytic host.

  14. The interactions of ants with their biotic environment.

    PubMed

    Chomicki, Guillaume; Renner, Susanne S

    2017-03-15

    This s pecial feature results from the symposium 'Ants 2016: ant interactions with their biotic environments' held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this s pecial feature After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication. © 2017 The Author(s).

  15. The interactions of ants with their biotic environment

    PubMed Central

    Renner, Susanne S.

    2017-01-01

    This special feature results from the symposium ‘Ants 2016: ant interactions with their biotic environments’ held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this special feature. After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication. PMID:28298352

  16. Fast and flexible: argentine ants recruit from nearby trails.

    PubMed

    Flanagan, Tatiana P; Pinter-Wollman, Noa M; Moses, Melanie E; Gordon, Deborah M

    2013-01-01

    Argentine ants (Linepithema humile) live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources.

  17. Insect navigation: do ants live in the now?

    PubMed

    Graham, Paul; Mangan, Michael

    2015-03-01

    Visual navigation is a critical behaviour for many animals, and it has been particularly well studied in ants. Decades of ant navigation research have uncovered many ways in which efficient navigation can be implemented in small brains. For example, ants show us how visual information can drive navigation via procedural rather than map-like instructions. Two recent behavioural observations highlight interesting adaptive ways in which ants implement visual guidance. Firstly, it has been shown that the systematic nest searches of ants can be biased by recent experience of familiar scenes. Secondly, ants have been observed to show temporary periods of confusion when asked to repeat a route segment, even if that route segment is very familiar. Taken together, these results indicate that the navigational decisions of ants take into account their recent experiences as well as the currently perceived environment. © 2015. Published by The Company of Biologists Ltd.

  18. Extrafloral nectar content alters foraging preferences of a predatory ant

    PubMed Central

    Wilder, Shawn M.; Eubanks, Micky D.

    2010-01-01

    We tested whether the carbohydrate and amino acid content of extrafloral nectar affected prey choice by a predatory ant. Fire ants, Solenopsis invicta, were provided with artificial nectar that varied in the presence of carbohydrates and amino acids and were then provided with two prey items that differed in nutritional content, female and male crickets. Colonies of fire ants provided with carbohydrate supplements consumed less of the female crickets and frequently did not consume the high-lipid ovaries of female crickets. Colonies of fire ants provided with amino acid supplements consumed less of the male crickets. While a number of studies have shown that the presence of extrafloral nectar or honeydew can affect ant foraging activity, these results suggest that the nutritional composition of extrafloral nectar is also important and can affect subsequent prey choice by predatory ants. Our results suggest that, by altering the composition of extrafloral nectar, plants could manipulate the prey preferences of ants foraging on them. PMID:19864270

  19. Harvester ant bioassay for assessing hazardous chemical waste sites

    SciTech Connect

    Gano, K.A.; Carlile, D.W.; Rogers, L.E.

    1984-12-01

    A technique was developed for using harvester ants, Pogonomyrmex owhyeei, in terrestrial bioassays. Procedures were developed for maintaining stock populations, handling ants, and exposing ants to toxic materials. Relative toxicities were determined by exposing ants to 10 different materials. These materials included three insecticides, Endrin, Aldrin, and Dieldrin; one herbicide, 2,4-D; three oil-like compounds, wood preservative, drilling fluid, and slop oil; and three heavy metals, copper, zinc, and cadmium. Ants were exposed in petri dishes containing soil amended with a particular toxicant. Under these test conditions, ants showed no sensitivity to the metals or 2,4-D. Ants were sensitive to themore » insecticides and oils in repeated tests, and relative toxicity remained consistent throughout. Aldrin was the most toxic material, followed by Dieldrin, Endrin, wood preservative, drilling fluid, and slop oil. 10 refs., 2 figs., 2 tabs.« less

  20. Exploring with PAM: Prospecting ANTS Missions for Solar System Surveys

    NASA Technical Reports Server (NTRS)

    Clark, P. E.; Rilee, M. L.; Curtis, S. A.

    2003-01-01

    ANTS (Autonomous Nano-Technology Swarm), a large (1000 member) swarm of nano to picoclass (10 to 1 kg) totally autonomous spacecraft, are being developed as a NASA advanced mission concept. ANTS, based on a hierarchical insect social order, use an evolvable, self-similar, hierarchical neural system in which individual spacecraft represent the highest level nodes. ANTS uses swarm intelligence attained through collective, cooperative interactions of the nodes at all levels of the system. At the highest levels this can take the form of cooperative, collective behavior among the individual spacecraft in a very large constellation. The ANTS neural architecture is designed for totally autonomous operation of complex systems including spacecraft constellations. The ANTS (Autonomous Nano Technology Swarm) concept has a number of possible applications. A version of ANTS designed for surveying and determining the resource potential of the asteroid belt, called PAM (Prospecting ANTS Mission), is examined here.

  1. Fast and Flexible: Argentine Ants Recruit from Nearby Trails

    PubMed Central

    Flanagan, Tatiana P.; Pinter-Wollman, Noa M.; Moses, Melanie E.; Gordon, Deborah M.

    2013-01-01

    Argentine ants (Linepithema humile) live in groups of nests connected by trails to each other and to stable food sources. In a field study, we investigated whether some ants recruit directly from established, persistent trails to food sources, thus accelerating food collection. Our results indicate that Argentine ants recruit nestmates to food directly from persistent trails, and that the exponential increase in the arrival rate of ants at baits is faster than would be possible if recruited ants traveled from distant nests. Once ants find a new food source, they walk back and forth between the bait and sometimes share food by trophallaxis with nestmates on the trail. Recruiting ants from nearby persistent trails creates a dynamic circuit, like those found in other distributed systems, which facilitates a quick response to changes in available resources. PMID:23967129

  2. Optic disc detection using ant colony optimization

    NASA Astrophysics Data System (ADS)

    Dias, Marcy A.; Monteiro, Fernando C.

    2012-09-01

    The retinal fundus images are used in the treatment and diagnosis of several eye diseases, such as diabetic retinopathy and glaucoma. This paper proposes a new method to detect the optic disc (OD) automatically, due to the fact that the knowledge of the OD location is essential to the automatic analysis of retinal images. Ant Colony Optimization (ACO) is an optimization algorithm inspired by the foraging behaviour of some ant species that has been applied in image processing for edge detection. Recently, the ACO was used in fundus images to detect edges, and therefore, to segment the OD and other anatomical retinal structures. We present an algorithm for the detection of OD in the retina which takes advantage of the Gabor wavelet transform, entropy and ACO algorithm. Forty images of the retina from DRIVE database were used to evaluate the performance of our method.

  3. Dead ant walking: a myrmecophilous beetle predator uses parasitoid host location cues to selectively prey on parasitized ants

    PubMed Central

    2016-01-01

    Myrmecophiles (i.e. organisms that associate with ants) use a variety of ecological niches and employ different strategies to survive encounters with ants. Because ants are typically excellent defenders, myrmecophiles may choose moments of weakness to take advantage of their ant associates. This hypothesis was studied in the rove beetle, Myrmedonota xipe, which associates with Azteca sericeasur ants in the presence of parasitoid flies. A combination of laboratory and field experiments show that M. xipe beetles selectively locate and prey upon parasitized ants. These parasitized ants are less aggressive towards beetles than healthy ants, allowing beetles to eat the parasitized ants alive without interruption. Moreover, behavioural assays and chemical analysis reveal that M. xipe are attracted to the ant's alarm pheromone, the same secretion used by the phorid fly parasitoids in host location. This strategy allows beetles access to an abundant but otherwise inaccessible resource, as A. sericeasur ants are typically highly aggressive. These results are the first, to our knowledge, to demonstrate a predator sharing cues with a parasitoid to gain access to an otherwise unavailable prey item. Furthermore, this work highlights the importance of studying ant–myrmecophile interactions beyond just their pairwise context. PMID:27512148

  4. Ant-Man and the quantum realm

    NASA Astrophysics Data System (ADS)

    Michalakis, Spiros

    2015-11-01

    I was in Los Angeles airport, stuffing French fries into my mouth and waiting for a flight to Charlotte, North Carolina, when my phone buzzed. The e-mail was from the Science and Entertainment Exchange, a non-profit organization working to elevate the level of science in the movies, and it told me to report to Atlanta to consult on a new superhero movie: Ant-Man.

  5. Alarm Pheromones of the Ant Atta Texana

    Treesearch

    John C. Moser; R. C. Brownlee; R. Silverstein

    1968-01-01

    Methyl-3-heptanone (0.59 μg/head) and 2-heptanone (0.14 μg/head) are the main volatile components of the mandibular glands of major workers. In the laboratory, worker ants detected and were attracted by 4-methyl-3-heptanone at a concentration of 5.7 x 10-13 g/cm3 (2.7 x 107 molecules...

  6. Dynamic Network Formation Using Ant Colony Optimization

    DTIC Science & Technology

    2009-03-01

    backhauls, VRP with pick-up and delivery, VRP with satellite facilities, and VRP with time windows (Murata & Itai , 2005). The general vehicle...given route is only visited once. The objective of the basic problem is to minimize a total cost as follows (Murata & Itai , 2005): M m mc 1 min...Problem based on Ant Colony System. Second Internation Workshop on Freight Transportation and Logistics. Palermo, Italy. Murata, T., & Itai , R. (2005

  7. Ant Lion Optimization algorithm for kidney exchanges.

    PubMed

    Hamouda, Eslam; El-Metwally, Sara; Tarek, Mayada

    2018-01-01

    The kidney exchange programs bring new insights in the field of organ transplantation. They make the previously not allowed surgery of incompatible patient-donor pairs easier to be performed on a large scale. Mathematically, the kidney exchange is an optimization problem for the number of possible exchanges among the incompatible pairs in a given pool. Also, the optimization modeling should consider the expected quality-adjusted life of transplant candidates and the shortage of computational and operational hospital resources. In this article, we introduce a bio-inspired stochastic-based Ant Lion Optimization, ALO, algorithm to the kidney exchange space to maximize the number of feasible cycles and chains among the pool pairs. Ant Lion Optimizer-based program achieves comparable kidney exchange results to the deterministic-based approaches like integer programming. Also, ALO outperforms other stochastic-based methods such as Genetic Algorithm in terms of the efficient usage of computational resources and the quantity of resulting exchanges. Ant Lion Optimization algorithm can be adopted easily for on-line exchanges and the integration of weights for hard-to-match patients, which will improve the future decisions of kidney exchange programs. A reference implementation for ALO algorithm for kidney exchanges is written in MATLAB and is GPL licensed. It is available as free open-source software from: https://github.com/SaraEl-Metwally/ALO_algorithm_for_Kidney_Exchanges.

  8. Polydomy in the ant Ectatomma opaciventre

    PubMed Central

    Tofolo, Viviane C.; Giannotti, Edilberto; Neves, Erika F.; Andrade, Luis H. C.; M. Lima, Sandro; Súarez, Yzel R.; Antonialli-Junior, William F.

    2014-01-01

    Abstract Tropical ants commonly exhibit a hyper-dispersed pattern of spatial distribution of nests. In polydomous species, nests may be satellites, that is, secondary structures of the main nest, where the queen is found. In order to evaluate whether the ant Ectatomma opaciventre Roger (Formicidae: Ectatomminae) uses the strategy of building polydomous nests, the spatial distribution pattern of 33 nests in a 1,800 m 2 degraded area located in Rio Claro, SP, Brazil, were investigated using the nearest neighbor method. To complement the results of this investigation, the cuticular chemical profile of eight colonies was analyzed using Fourier transform infrared photoacoustic spectrosco-py (FTIR-PAS). The nests of E. opaciventre presented a hyper-dispersed or regular distribution, which is the most common in ants. The analysis of the cuticular hydrocarbons apparently con-firmed the hypothesis that this species is polydomous, since the chemical profiles of all studied colonies with nests at different sites were very similar to the chemical signature of the single found queen and were also different from those of colonies used as control. PMID:25373168

  9. Dispersal Polymorphisms in Invasive Fire Ants

    PubMed Central

    Helms, Jackson A.; Godfrey, Aaron

    2016-01-01

    In the Found or Fly (FoF) hypothesis ant queens experience reproduction-dispersal tradeoffs such that queens with heavier abdomens are better at founding colonies but are worse flyers. We tested predictions of FoF in two globally invasive fire ants, Solenopsis geminata (Fabricius, 1804) and S. invicta (Buren, 1972). Colonies of these species may produce two different monogyne queen types—claustral queens with heavy abdomens that found colonies independently, and parasitic queens with small abdomens that enter conspecific nests. Claustral and parasitic queens were similarly sized, but the abdomens of claustral queens weighed twice as much as those of their parasitic counterparts. Their heavier abdomens adversely impacted morphological predictors of flight ability, resulting in 32–38% lower flight muscle ratios, 55–63% higher wing loading, and 32–33% higher abdomen drag. In lab experiments maximum flight durations in claustral S. invicta queens decreased by about 18 minutes for every milligram of abdomen mass. Combining our results into a simple fitness tradeoff model, we calculated that an average parasitic S. invicta queen could produce only 1/3 as many worker offspring as a claustral queen, but could fly 4 times as long and have a 17- to 36-fold larger potential colonization area. Investigations of dispersal polymorphisms and their associated tradeoffs promises to shed light on range expansions in invasive species, the evolution of alternative reproductive strategies, and the selective forces driving the recurrent evolution of parasitism in ants. PMID:27082115

  10. Dispersal Polymorphisms in Invasive Fire Ants.

    PubMed

    Helms, Jackson A; Godfrey, Aaron

    2016-01-01

    In the Found or Fly (FoF) hypothesis ant queens experience reproduction-dispersal tradeoffs such that queens with heavier abdomens are better at founding colonies but are worse flyers. We tested predictions of FoF in two globally invasive fire ants, Solenopsis geminata (Fabricius, 1804) and S. invicta (Buren, 1972). Colonies of these species may produce two different monogyne queen types-claustral queens with heavy abdomens that found colonies independently, and parasitic queens with small abdomens that enter conspecific nests. Claustral and parasitic queens were similarly sized, but the abdomens of claustral queens weighed twice as much as those of their parasitic counterparts. Their heavier abdomens adversely impacted morphological predictors of flight ability, resulting in 32-38% lower flight muscle ratios, 55-63% higher wing loading, and 32-33% higher abdomen drag. In lab experiments maximum flight durations in claustral S. invicta queens decreased by about 18 minutes for every milligram of abdomen mass. Combining our results into a simple fitness tradeoff model, we calculated that an average parasitic S. invicta queen could produce only 1/3 as many worker offspring as a claustral queen, but could fly 4 times as long and have a 17- to 36-fold larger potential colonization area. Investigations of dispersal polymorphisms and their associated tradeoffs promises to shed light on range expansions in invasive species, the evolution of alternative reproductive strategies, and the selective forces driving the recurrent evolution of parasitism in ants.

  11. The invasive ant, Solenopsis invicta, reduces herpetofauna richness and abundance

    USGS Publications Warehouse

    Allen, Craig R.; Birge, Hannah E.; Slater, J.; Wiggers, E.

    2017-01-01

    Amphibians and reptiles are declining globally. One potential cause of this decline includes impacts resulting from co-occurrence with non-native red imported fire ant, Solenopsis invicta. Although a growing body of anecdotal and observational evidence from laboratory experiments supports this hypothesis, there remains a lack of field scale manipulations testing the effect of fire ants on reptile and amphibian communities. We addressed this gap by measuring reptile and amphibian (“herpetofauna”) community response to successful fire ant reductions over the course of 2 years following hydramethylnon application to five 100–200 ha plots in southeastern coastal South Carolina. By assessing changes in relative abundance and species richness of herpetofauna in response to fire ant reductions, we were able to assess whether some species were particularly vulnerable to fire ant presence, and whether this sensitivity manifested at the community level. We found that herpetofauna abundance and species richness responded positively to fire ant reductions. Our results document that even moderate populations of red imported fire ants decrease both the abundance and diversity of herpetofauna. Given global herpetofauna population declines and continued spread of fire ants, there is urgency to understand the impacts of fire ants beyond anecdotal and singles species studies. Our results provides the first community level investigation addressing these dynamics, by manipulating fire ant abundance to reveal a response in herpetofauna species abundance and richness.

  12. Predaceous ants, beach replenishment, and nest placement by sea turtles.

    PubMed

    Wetterer, James K; Wood, Lawrence D; Johnson, Chris; Krahe, Holly; Fitchett, Stephanie

    2007-10-01

    Ants known for attacking and killing hatchling birds and reptiles include the red imported fire ant (Solenopsis invicta Buren), tropical fire ant [Solenopsis geminata (Fabr.)], and little fire ant [Wasmannia auropunctata (Roger)]. We tested whether sea turtle nest placement influenced exposure to predaceous ants. In 2000 and 2001, we surveyed ants along a Florida beach where green turtles (Chelonia mydas L.), leatherbacks (Dermochelys coriacea Vandelli), and loggerheads (Caretta caretta L.) nest. Part of the beach was artificially replenished between our two surveys. As a result, mean beach width experienced by nesting turtles differed greatly between the two nesting seasons. We surveyed 1,548 sea turtle nests (2000: 909 nests; 2001: 639 nests) and found 22 ant species. S. invicta was by far the most common species (on 431 nests); S. geminata and W. auropunctata were uncommon (on 3 and 16 nests, respectively). In 2000, 62.5% of nests had ants present (35.9% with S. invicta), but in 2001, only 30.5% of the nests had ants present (16.4% with S. invicta). Turtle nests closer to dune vegetation had significantly greater exposure to ants. Differences in ant presence on turtle nests between years and among turtle species were closely related to differences in nest placement relative to dune vegetation. Beach replenishment significantly lowered exposure of nests to ants because on the wider beaches turtles nested farther from the dune vegetation. Selective pressures on nesting sea turtles are altered both by the presence of predaceous ants and the practice of beach replenishment.

  13. Chemically armed mercenary ants protect fungus-farming societies.

    PubMed

    Adams, Rachelle M M; Liberti, Joanito; Illum, Anders A; Jones, Tappey H; Nash, David R; Boomsma, Jacobus J

    2013-09-24

    The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit from their costly guest ants behaving as a functional soldier caste to meet lethal threats from agro-predator raiders. The fundamentally different life histories of the agro-predators and guest ants appear to facilitate their coexistence in a negative frequency-dependent manner. Because a guest ant colony is committed for life to a single host colony, the guests would harm their own interests by not defending the host that they continue to exploit. This conditional mutualism is analogous to chronic sickle cell anemia enhancing the resistance to malaria and to episodes in human history when mercenary city defenders offered either net benefits or imposed net costs, depending on the level of threat from invading armies.

  14. Chemically armed mercenary ants protect fungus-farming societies

    PubMed Central

    Adams, Rachelle M. M.; Liberti, Joanito; Illum, Anders A.; Jones, Tappey H.; Nash, David R.; Boomsma, Jacobus J.

    2013-01-01

    The ants are extraordinary in having evolved many lineages that exploit closely related ant societies as social parasites, but social parasitism by distantly related ants is rare. Here we document the interaction dynamics among a Sericomyrmex fungus-growing ant host, a permanently associated parasitic guest ant of the genus Megalomyrmex, and a raiding agro-predator of the genus Gnamptogenys. We show experimentally that the guest ants protect their host colonies against agro-predator raids using alkaloid venom that is much more potent than the biting defenses of the host ants. Relatively few guest ants are sufficient to kill raiders that invariably exterminate host nests without a cohabiting guest ant colony. We also show that the odor of guest ants discourages raider scouts from recruiting nestmates to host colonies. Our results imply that Sericomyrmex fungus-growers obtain a net benefit from their costly guest ants behaving as a functional soldier caste to meet lethal threats from agro-predator raiders. The fundamentally different life histories of the agro-predators and guest ants appear to facilitate their coexistence in a negative frequency-dependent manner. Because a guest ant colony is committed for life to a single host colony, the guests would harm their own interests by not defending the host that they continue to exploit. This conditional mutualism is analogous to chronic sickle cell anemia enhancing the resistance to malaria and to episodes in human history when mercenary city defenders offered either net benefits or imposed net costs, depending on the level of threat from invading armies. PMID:24019482

  15. When invasive ants meet: effects of outbreeding on queen performance in the tramp ant Cardiocondyla itsukii.

    PubMed

    Heinze, Jürgen; Frohschammer, Sabine; Bernadou, Abel

    2017-08-18

    Most disturbed habitats in the tropics and subtropics harbor numerous species of invasive ants, and occasionally the same species has been introduced repeatedly from multiple geographical sources. We examined how experimental crossbreeding between sexuals from different populations affects the fitness of queens of the tramp ant Cardiocondyla itsukii, which is widely distributed in Asia and the Pacific Islands. Eggs laid by queens that mated with nestmate males had a higher hatching rate than eggs laid by queens mated to males from neighboring (Hawaii × Kauai) or distant introduced populations (Hawaii/Kauai × Okinawa). Furthermore, inbreeding queens had a longer lifespan and produced a less female-biased offspring sex ratio than queens from allopatric mating. This suggests that the genetic divergence between different source populations may already be so large that in case of multiple invasions eventual crossbreeding might negatively affect the fitness of tramp ants. © 2017 Institute of Zoology, Chinese Academy of Sciences.

  16. Food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions in an arid environment

    NASA Astrophysics Data System (ADS)

    Flores-Flores, Rocío Vianey; Aguirre, Armando; Anjos, Diego V.; Neves, Frederico S.; Campos, Ricardo I.; Dáttilo, Wesley

    2018-02-01

    In this study, we conducted a series of experiments in a population of Vachellia constricta (Fabaceae) in the arid Tehuacan-Cuicatláan valley, Mexico, in order to evaluate if the food source quality and ant dominance hierarchy influence the outcomes of ant-plant interactions. Using an experiment with artificial nectaries, we observed that ants foraging on food sources with higher concentration of sugar are quicker in finding and attacking potential herbivorous insects. More specifically, we found that the same ant species may increase their defence effectiveness according to the quality of food available. These findings indicate that ant effectiveness in plant protection is context-dependent and may vary according to specific individual characteristics of plants. In addition, we showed that competitively superior ant species tend to dominate plants in periods with high nectar activity, emphasizing the role of the dominance hierarchy structuring ant-plant interactions. However, when high sugar food sources were experimentally available ad libitum, the nocturnal and competitively superior ant species, Camponotus atriceps, did not dominate the artificial nectaries during the day possibly due to limitation of its thermal tolerance. Therefore, temporal niche partitioning may be allowing the coexistence of two dominant ant species (Camponotus rubritorax during the day and C. atriceps at night) on V. constricta. Our findings indicate that the quality of the food source, and temporal shifts in ant dominance are key factors which structure the biotic plant defences in an arid environment.

  17. Ants at Plant Wounds: A Little-Known Trophic Interaction with Evolutionary Implications for Ant-Plant Interactions.

    PubMed

    Staab, Michael; Fornoff, Felix; Klein, Alexandra-Maria; Blüthgen, Nico

    2017-09-01

    Extrafloral nectaries (EFNs) allow plants to engage in mutualisms with ants, preventing herbivory in exchange for food. EFNs occur scattered throughout the plant phylogeny and likely evolved independent from herbivore-created wounds subsequently visited by ants collecting leaked sap. Records of wound-feeding ants are, however, anecdotal. By surveying 38,000 trees from 40 species, we conducted the first quantitative ecological study of this overlooked behavior. Ant-wound interactions were widespread (0.5% of tree individuals) and occurred on 23 tree species. Interaction networks were opportunistic, closely resembling ant-EFN networks. Fagaceae, a family lacking EFNs, was strongly overrepresented. For Fagaceae, ant occurrence at wounds correlated with species-level leaf damage, potentially indicating that wounds may attract mutualistic ants, which supports the hypothesis of ant-tended wounds as precursors of ant-EFN mutualisms. Given that herbivore wounds are common, wound sap as a steadily available food source might further help to explain the overwhelming abundance of ants in (sub)tropical forest canopies.

  18. How Load-Carrying Ants Avoid Falling Over: Mechanical Stability during Foraging in Atta vollenweideri Grass-Cutting Ants

    PubMed Central

    Moll, Karin; Roces, Flavio; Federle, Walter

    2013-01-01

    Background Foraging workers of grass-cutting ants (Atta vollenweideri) regularly carry grass fragments larger than their own body. Fragment length has been shown to influence the ants’ running speed and thereby the colony’s food intake rate. We investigated whether and how grass-cutting ants maintain stability when carrying fragments of two different lengths but identical mass. Principal Findings Ants carried all fragments in an upright, backwards-tilted position, but held long fragments more vertically than short ones. All carrying ants used an alternating tripod gait, where mechanical stability was increased by overlapping stance phases of consecutive steps. The overlap was greatest for ants carrying long fragments, resulting in more legs contacting the ground simultaneously. For all ants, the projection of the total centre of mass (ant and fragment) was often outside the supporting tripod, i.e. the three feet that would be in stance for a non-overlapping tripod gait. Stability was only achieved through additional legs in ground contact. Tripod stability (quantified as the minimum distance of the centre of mass to the edge of the supporting tripod) was significantly smaller for ants with long fragments. Here, tripod stability was lowest at the beginning of each step, when the center of mass was near the posterior margin of the supporting tripod. By contrast, tripod stability was lowest at the end of each step for ants carrying short fragments. Consistently, ants with long fragments mainly fell backwards, whereas ants carrying short fragments mainly fell forwards or to the side. Assuming that transporting ants adjust neither the fragment angle nor the gait, they would be less stable and more likely to fall over. Conclusions In grass-cutting ants, the need to maintain static stability when carrying long grass fragments has led to multiple kinematic adjustments at the expense of a reduced material transport rate. PMID:23300994

  19. Just follow your nose: homing by olfactory cues in ants.

    PubMed

    Steck, Kathrin

    2012-04-01

    How is an ant-equipped with a brain that barely exceeds the size of a pinhead-capable of achieving navigational marvels? Even though evidences suggest that navigation is a multimodal process, ants heavily depend on olfactory cues-of pheromonal and non-pheromonal nature-for foraging and orientation. Recent studies have directed their attention to the efficiency of pheromone trail networks. Advances in neurophysiological techniques make it possible to investigate trail pheromone processing in the ant's brain. In addition to relying on pheromone odours, ants also make use of volatiles emanating from the nest surroundings. Deposited in the vicinity of the nest, these home-range markings help the ants to home after a foraging run. Furthermore, olfactory landmarks associated with the nest enhance ants' homing abilities. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Cascading trait-mediated interactions induced by ant pheromones

    PubMed Central

    Hsieh, Hsun-Yi; Liere, Heidi; Soto, Estelí J; Perfecto, Ivette

    2012-01-01

    Trait-mediated indirect interactions (TMII) can be as important as density-mediated indirect interactions. Here, we provide evidence for a novel trait-mediated cascade (where one TMII affects another TMII) and demonstrate that the mechanism consists of a predator eavesdropping on chemical signaling. Ants protect scale insects from predation by adult coccinellid beetles – the first TMII. However, parasitic phorid flies reduce ant foraging activity by 50% – the second TMII, providing a window of opportunity for female beetles to oviposit in high-quality microsites. Beetle larvae are protected from ant predation and benefit from living in patches with high scale densities. We demonstrate that female beetles can detect pheromones released by the ant when attacked by phorids, and that only females, and especially gravid females, are attracted to the ant pheromone. As ants reduce their movement when under attack by phorids, we conclude that phorids facilitate beetle oviposition, thus producing the TMII cascade. PMID:23139877

  1. Ant tending influences soldier production in a social aphid.

    PubMed

    Shingleton, A W; Foster, W A

    2000-09-22

    The aphid Pseudoregma sundanica (Van der Goot) (Homoptera: Aphididae) has two defence strategies. It is obligatorily tended by various species of ant and also produces sterile soldiers. We investigated how they allocate their investment in these two strategies. We measured the size, number of soldiers, number and species of tending ant, and number and species of predators in P. sundanica populations. We found that the level of ant tending correlated negatively with soldier investment in P. sundanica. The species of tending ant also influenced soldier investment. We excluded ants from aphid populations and recorded changes in population size and structure over four weeks. Ant exclusion led to population decline and extinction. At the same time, surviving populations showed a significant increase in soldier investment. The data demonstrate that social aphids can adjust their investment in soldiers in direct response to environmental change.

  2. The mineralogy of Ba- and Zr-rich alkaline pegmatites from Gordon Butte, Crazy Mountains (Montana, USA): comparisons between potassic and sodic agpaitic pegmatites

    NASA Astrophysics Data System (ADS)

    Chakhmouradian, Anton; Mitchell, Roger

    2002-01-01

    At Gordon Butte (Crazy Mountains, Montana), agpaitic nepheline-syenite pegmatites intrude potassic alkaline rocks (principally, malignites and nepheline microsyenites). All pegmatite veins are composed predominantly of potassium feldspar, nepheline, prismatic aegirine, barytolamprophyllite, wadeite, eudialyte, loparite-(Ce) and altered rinkite ("vudyavrite") embedded in spherulitic and fibrous aegirine. Well-differentiated veins contain "pockets" filled with calcite, fluorapatite, mangan-neptunite, Mn-Ti-enriched prismatic aegirine, calcium catapleiite, and an unidentified Ca-Ti silicate. The potassium feldspar corresponds to Ba-rich sanidine with relatively low Na contents. The nepheline contains low levels of SiO2 and elevated Fe contents. The compositions of nepheline cluster in the lower portion of the Morozewicz-Buerger convergence field, indicating low-temperature crystallization and/or chemical re-equilibration of this mineral. The association of sanidine with nearly stoichiometric nepheline is unusual for agpaitic rocks and probably reflects inhibition of Al/Si ordering in the feldspar by Ba. At least four types of clinopyroxene can be distinguished on the basis of their morphology and composition. All these types correspond to Al- and Ca-poor aegirine (typically <0.6 and 2.6 wt% Al2O3 and CaO, respectively). The overall evolutionary trend of clinopyroxene in the Gordon Butte rocks is from Fe-poor diopside to aegirine-augite in the malignites and nepheline microsyenites, and culminates with the pegmatitic aegirine. This trend is characteristic for potassic alkaline complexes and results from preferential partitioning of Fe2+ into biotite during the magmatic crystallization. Barytolamprophyllite in the pegmatites is primary (as opposed to deuteric); only a few crystals contain a core composed of lamprophyllite. The evolutionary history of the Gordon Butte pegmatites can be subdivided into primary, agpaitic, and deuteric stages. The earliest paragenesis to

  3. Consuming fire ants reduces northern bobwhite survival and weight gain

    USGS Publications Warehouse

    Myers, P.E.; Allen, Craig R.; Birge, Hannah E.

    2014-01-01

    Northern bobwhite quail, Colinus virginianus (L.) (Galliformes: Odontophoridae), population declines are well documented, but pinpointing the reasons for these decreases has proven elusive. Bobwhite population declines are attributed primarily to loss of habitat and land use changes. This, however, does not entirely explain population declines in areas intensively managed for bobwhites. Although previous research demonstrates the negative impact of red imported fire ant (Solenopsis invicta Buren) (Hymenoptera: Formicidae) on northern bobwhites, the mechanisms underlying this effect are largely unknown. To meet the protein demands of early growth and development, bobwhite chicks predominantly consume small insects, of which ants are a substantial proportion. Fire ants alter ant community dynamics by often reducing native ant diversity and abundance while concurrently increasing the abundance of individuals. Fire ants have negative effects on chicks, but they are also a large potential protein source, making it difficult to disentangle their net effect on bobwhite chicks. To help investigate these effects, we conducted a laboratory experiment to understand (1) whether or not bobwhites consume fire ants, and (2) how the benefits of this consumption compare to the deleterious impacts of bobwhite chick exposure to fire ants. Sixty bobwhite chicks were separated into two groups of 30; one group was provided with starter feed only and the second group was provided with feed and fire ants. Bobwhite chicks were observed feeding on fire ants. Chicks that fed on fire ants had reduced survival and weight gain. Our results show that, while fire ants increase potential food sources for northern bobwhite, their net effect on bobwhite chicks is deleterious. This information will help inform land managers and commercial bobwhite rearing operations.

  4. Insecticide Transfer Efficiency and Lethal Load in Argentine Ants

    DOE PAGES

    Hooper-Bui, L. M.; Kwok, E S.C.; Buchholz, B. A.; ...

    2015-07-03

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14C-sucrose, 14C-hydramethylnon, and 14C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), butmore » dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). Moreover, the distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. The bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.« less

  5. Insecticide Transfer Efficiency and Lethal Load in Argentine Ants

    SciTech Connect

    Hooper-Bui, L. M.; Kwok, E S.C.; Buchholz, B. A.

    Trophallaxis between individual worker ants and the toxicant load in dead and live Argentine ants (Linepithema humile) in colonies exposed to fipronil and hydramethylnon experimental baits were examined using accelerator mass spectrometry (AMS). About 50% of the content of the crop containing trace levels of 14C-sucrose, 14C-hydramethylnon, and 14C-fipronil was shared between single donor and recipient ants. Dead workers and queens contained significantly more hydramethylnon (122.7 and 22.4 amol/μg ant, respectively) than did live workers and queens (96.3 and 10.4 amol/μg ant, respectively). Dead workers had significantly more fipronil (420.3 amol/μg ant) than did live workers (208.5 amol/μg ant), butmore » dead and live queens had equal fipronil levels (59.5 and 54.3 amol/μg ant, respectively). Moreover, the distribution of fipronil differed within the bodies of dead and live queens; the highest amounts of fipronil were recovered in the thorax of dead queens whereas live queens had the highest levels in the head. Resurgence of polygynous ant colonies treated with hydramethylnon baits may be explained by queen survival resulting from sublethal doses due to a slowing of trophallaxis throughout the colony. The bait strategies and dose levels for controlling insect pests need to be based on the specific toxicant properties and trophic strategies for targeting the entire colony.« less

  6. Five new records of ants (Hymenoptera: Formicidae) for Nebraska

    USGS Publications Warehouse

    Nemec, Kristine T.; Trager, James C.; Manley, Elizabeth; Allen, Craig R.

    2012-01-01

    Ants are ubiquitous and influential organisms in terrestrial ecosystems. About 1,000 ant species occur in North America, where they are found in nearly every habitat (Fisher and Cover 2007). Ants are critical to ecological processes and structure. Ants affect soils via tunneling activity (Baxter and Hole 1967), disperse plant seeds (Lengyel et al. 2009), prey upon a variety of insects and other invertebrates (Way and Khoo 1992, Folgarait 1998), are often effective primary consumers through their prodigious consumption of floral and especially extrafloral nectar, and honeydew (Tobin 1994), and serve as prey for invertebrates (Gotelli 1996, Gastreich 1999) and vertebrates (Reiss 2001).

  7. Looking and homing: how displaced ants decide where to go.

    PubMed

    Zeil, Jochen; Narendra, Ajay; Stürzl, Wolfgang

    2014-01-01

    We caught solitary foragers of the Australian Jack Jumper ant, Myrmecia croslandi, and released them in three compass directions at distances of 10 and 15 m from the nest at locations they have never been before. We recorded the head orientation and the movements of ants within a radius of 20 cm from the release point and, in some cases, tracked their subsequent paths with a differential GPS. We find that upon surfacing from their transport vials onto a release platform, most ants move into the home direction after looking around briefly. The ants use a systematic scanning procedure, consisting of saccadic head and body rotations that sweep gaze across the scene with an average angular velocity of 90° s(-1) and intermittent changes in turning direction. By mapping the ants' gaze directions onto the local panorama, we find that neither the ants' gaze nor their decisions to change turning direction are clearly associated with salient or significant features in the scene. Instead, the ants look most frequently in the home direction and start walking fast when doing so. Displaced ants can thus identify home direction with little translation, but exclusively through rotational scanning. We discuss the navigational information content of the ants' habitat and how the insects' behaviour informs us about how they may acquire and retrieve that information.

  8. Free and constrained expansion of fire ant aggregations

    NASA Astrophysics Data System (ADS)

    Fernandez-Nieves, Alberto; Anderson, Caleb

    We revisit the classical free and constrained expansion of ideal gases with fire ant aggregations. We use rectangular parallel plates to confine fire ants to two-dimensions and watch how these expand when the plates are horizontal or when these are vertical. In the first case, the ants expand in a rather disorganized fashion, while in the second case, when there is work involved, the expansion is rather organized. The behavior is reminiscent of what is expected from the so called reversible process theorems of classical thermodynamics despite the ant aggregation is intrinsically out of equilibrium. This talk will focus on these results and in related observations in the same experimental setting.

  9. Evolution and ecology of directed aerial descent in arboreal ants.

    PubMed

    Yanoviak, Stephen P; Munk, Yonatan; Dudley, Robert

    2011-12-01

    Directed aerial descent (DAD) is used by a variety of arboreal animals to escape predators, to remain in the canopy, and to access resources. Here, we build upon the discovery of DAD in ants of tropical canopies by summarizing its known phylogenetic distribution among ant genera, and within both the subfamily Pseudomyrmecinae and the genus Cephalotes. DAD has multiple evolutionary origins in ants, occurring independently in numerous genera in the subfamilies Myrmicinae, Formicinae, and Pseudomyrmecinae. Ablation experiments and video recordings of ants in a vertical wind tunnel showed that DAD in Cephalotes atratus is achieved via postural changes, specifically orientation of the legs and gaster. The occurrence of DAD in Formicinae indicates that the presence of a postpetiole is not essential for the behavior. Evidence to date indicates that gliding behavior is accomplished by visual targeting mediated by the compound eyes, and is restricted to diurnally active ants that nest in trees. Occlusion of ocelli in Pseudomyrmex gracilis workers had no effect on their success or performance in gliding. Experimental assessment of the fate of ants that fall to the understory showed that ants landing in water are 15 times more likely to suffer lethal attacks than are ants landing in leaf litter. Variation in both the aerodynamic mechanisms and selective advantages of DAD merits further study given the broad taxonomic diversity of arboreal ants that engage in this intriguing form of flight.

  10. Ant-plant-herbivore interactions in the neotropical cerrado savanna.

    PubMed

    Oliveira, Paulo S; Freitas, André V L

    2004-12-01

    The Brazilian cerrado savanna covers nearly 2 million km2 and has a high incidence on foliage of various liquid food sources such as extrafloral nectar and insect exudates. These liquid rewards generate intense ant activity on cerrado foliage, making ant-plant-herbivore interactions especially prevalent in this biome. We present data on the distribution and abundance of extrafloral nectaries in the woody flora of cerrado communities and in the flora of other habitats worldwide, and stress the relevance of liquid food sources (including hemipteran honeydew) for the ant fauna. Consumption by ants of plant and insect exudates significantly affects the activity of the associated herbivores of cerrado plant species, with varying impacts on the reproductive output of the plants. Experiments with an ant-plant-butterfly system unequivocally demonstrate that the behavior of both immature and adult lepidopterans is closely related to the use of a risky host plant, where intensive visitation by ants can have a severe impact on caterpillar survival. We discuss recent evidence suggesting that the occurrence of liquid rewards on leaves plays a key role in mediating the foraging ecology of foliage-dwelling ants, and that facultative ant-plant mutualisms are important in structuring the community of canopy arthropods. Ant-mediated effects on cerrado herbivore communities can be revealed by experiments performed on wide spatial scales, including many environmental factors such as soil fertility and vegetation structure. We also present some research questions that could be rewarding to investigate in this major neotropical savanna.

  11. Improved Ant Colony Clustering Algorithm and Its Performance Study

    PubMed Central

    Gao, Wei

    2016-01-01

    Clustering analysis is used in many disciplines and applications; it is an important tool that descriptively identifies homogeneous groups of objects based on attribute values. The ant colony clustering algorithm is a swarm-intelligent method used for clustering problems that is inspired by the behavior of ant colonies that cluster their corpses and sort their larvae. A new abstraction ant colony clustering algorithm using a data combination mechanism is proposed to improve the computational efficiency and accuracy of the ant colony clustering algorithm. The abstraction ant colony clustering algorithm is used to cluster benchmark problems, and its performance is compared with the ant colony clustering algorithm and other methods used in existing literature. Based on similar computational difficulties and complexities, the results show that the abstraction ant colony clustering algorithm produces results that are not only more accurate but also more efficiently determined than the ant colony clustering algorithm and the other methods. Thus, the abstraction ant colony clustering algorithm can be used for efficient multivariate data clustering. PMID:26839533

  12. The Evolution of Invasiveness in Garden Ants

    PubMed Central

    Cremer, Sylvia; Ugelvig, Line V.; Drijfhout, Falko P.; Schlick-Steiner, Birgit C.; Steiner, Florian M.; Seifert, Bernhard; Hughes, David P.; Schulz, Andreas; Petersen, Klaus S.; Konrad, Heino; Stauffer, Christian; Kiran, Kadri; Espadaler, Xavier; d'Ettorre, Patrizia; Aktaç, Nihat; Eilenberg, Jørgen; Jones, Graeme R.; Nash, David R.; Pedersen, Jes S.; Boomsma, Jacobus J.

    2008-01-01

    It is unclear why some species become successful invaders whilst others fail, and whether invasive success depends on pre-adaptations already present in the native range or on characters evolving de-novo after introduction. Ants are among the worst invasive pests, with Lasius neglectus and its rapid spread through Europe and Asia as the most recent example of a pest ant that may become a global problem. Here, we present the first integrated study on behavior, morphology, population genetics, chemical recognition and parasite load of L. neglectus and its non-invasive sister species L. turcicus. We find that L. neglectus expresses the same supercolonial syndrome as other invasive ants, a social system that is characterized by mating without dispersal and large networks of cooperating nests rather than smaller mutually hostile colonies. We conclude that the invasive success of L. neglectus relies on a combination of parasite-release following introduction and pre-adaptations in mating system, body-size, queen number and recognition efficiency that evolved long before introduction. Our results challenge the notion that supercolonial organization is an inevitable consequence of low genetic variation for chemical recognition cues in small invasive founder populations. We infer that low variation and limited volatility in cuticular hydrocarbon profiles already existed in the native range in combination with low dispersal and a highly viscous population structure. Human transport to relatively disturbed urban areas thus became the decisive factor to induce parasite release, a well established general promoter of invasiveness in non-social animals and plants, but understudied in invasive social insects. PMID:19050762

  13. [Syagrus romanzoffiana (Arecaceae) seed utilization by ants in a secondary forest in South Brazil].

    PubMed

    Silva, Fernanda R; Begnini, Romualdo M; Klier, Vinícius A; Scherer, Karla Z; Lopes, Benedito C; Castellani, Tânia T

    2009-01-01

    Ants can nest in a wide variety of substracts. This paper shows Syagrus romanzoffiana seed utilization by ants in an Atlantic secondary forest. We report 29 seeds occupied by small-bodied ants, with 27 of them showing at least two ant development stages. Although a large number of seeds were sampled, a low level of ant occupation was observed.

  14. Ecology: 'Devil's gardens' bedevilled by ants.

    PubMed

    Frederickson, Megan E; Greene, Michael J; Gordon, Deborah M

    2005-09-22

    'Devil's gardens' are large stands of trees in the Amazonian rainforest that consist almost entirely of a single species, Duroia hirsuta, and, according to local legend, are cultivated by an evil forest spirit. Here we show that the ant Myrmelachista schumanni, which nests in D. hirsuta stems, creates devil's gardens by poisoning all plants except its host plants with formic acid. By killing these other plants, M. schumanni provides its colonies with abundant nest sites--a long-lasting benefit as colonies can live for 800 years.

  15. The acacia ants revisited: convergent evolution and biogeographic context in an iconic ant/plant mutualism

    PubMed Central

    2017-01-01

    Phylogenetic and biogeographic analyses can enhance our understanding of multispecies interactions by placing the origin and evolution of such interactions in a temporal and geographical context. We use a phylogenomic approach—ultraconserved element sequence capture—to investigate the evolutionary history of an iconic multispecies mutualism: Neotropical acacia ants (Pseudomyrmex ferrugineus group) and their associated Vachellia hostplants. In this system, the ants receive shelter and food from the host plant, and they aggressively defend the plant against herbivores and competing plants. We confirm the existence of two separate lineages of obligate acacia ants that convergently occupied Vachellia and evolved plant-protecting behaviour, from timid ancestors inhabiting dead twigs in rainforest. The more diverse of the two clades is inferred to have arisen in the Late Miocene in northern Mesoamerica, and subsequently expanded its range throughout much of Central America. The other lineage is estimated to have originated in southern Mesoamerica about 3 Myr later, apparently piggy-backing on the pre-existing mutualism. Initiation of the Pseudomyrmex/Vachellia interaction involved a shift in the ants from closed to open habitats, into an environment with more intense plant herbivory. Comparative studies of the two lineages of mutualists should provide insight into the essential features binding this mutualism. PMID:28298350

  16. Partial incompatibility between ants and symbiotic fungi in two sympatric species of Acromyrmex leaf-cutting ants.

    PubMed

    Bot, A N; Rehner, S A; Boomsma, J J

    2001-10-01

    We investigate the nature and duration of incompatibility between certain combinations of Acromyrmex leaf-cutting ants and symbiotic fungi, taken from sympatric colonies of the same or a related species. Ant-fungus incompatibility appeared to be largely independent of the ant species involved, but could be explained partly by genetic differences among the fungus cultivars. Following current theoretical considerations, we develop a hypothesis, originally proposed by S. A. Frank, that the observed incompatibilities are ultimately due to competitive interactions between genetically different fungal lineages, and we predict that the ants should have evolved mechanisms to prevent such competition between cultivars within a single garden. This requires that the ants are able to recognize unfamiliar fungi, and we show that this is indeed the case. Amplified fragment length polymorphism genotyping further shows that the two sympatric Acromyrmex species share each other's major lineages of cultivar, confirming that horizontal transfer does occasionally take place. We argue and provide some evidence that chemical substances produced by the fungus garden may mediate recognition of alien fungi by the ants. We show that incompatibility between ants and transplanted, genetically different cultivars is indeed due to active killing of the novel cultivar by the ants. This incompatibility disappears when ants are force-fed the novel cultivar for about a week, a result that is consistent with our hypothesis of recognition induced by the resident fungus and eventual replacement of incompatibility compounds during force-feeding.

  17. Nectar Theft and Floral Ant-Repellence: A Link between Nectar Volume and Ant-Repellent Traits?

    PubMed Central

    Ballantyne, Gavin; Willmer, Pat

    2012-01-01

    As flower visitors, ants rarely benefit a plant. They are poor pollinators, and can also disrupt pollination by deterring other flower visitors, or by stealing nectar. Some plant species therefore possess floral ant-repelling traits. But why do particular species have such traits when others do not? In a dry forest in Costa Rica, of 49 plant species around a third were ant-repellent at very close proximity to a common generalist ant species, usually via repellent pollen. Repellence was positively correlated with the presence of large nectar volumes. Repellent traits affected ant species differently, some influencing the behaviour of just a few species and others producing more generalised ant-repellence. Our results suggest that ant-repellent floral traits may often not be pleiotropic, but instead could have been selected for as a defence against ant thieves in plant species that invest in large volumes of nectar. This conclusion highlights to the importance of research into the cost of nectar production in future studies into ant-flower interactions. PMID:22952793

  18. Evolution of long centromeres in fire ants.

    PubMed

    Huang, Yu-Ching; Lee, Chih-Chi; Kao, Chia-Yi; Chang, Ni-Chen; Lin, Chung-Chi; Shoemaker, DeWayne; Wang, John

    2016-09-15

    Centromeres are essential for accurate chromosome segregation, yet sequence conservation is low even among closely related species. Centromere drive predicts rapid turnover because some centromeric sequences may compete better than others during female meiosis. In addition to sequence composition, longer centromeres may have a transmission advantage. We report the first observations of extremely long centromeres, covering on average 34 % of the chromosomes, in the red imported fire ant Solenopsis invicta. By comparison, cytological examination of Solenopsis geminata revealed typical small centromeric constrictions. Bioinformatics and molecular analyses identified CenSol, the major centromeric satellite DNA repeat. We found that CenSol sequences are very similar between the two species but the CenSol copy number in S. invicta is much greater than that in S. geminata. In addition, centromere expansion in S. invicta is not correlated with the duplication of CenH3. Comparative analyses revealed that several closely related fire ant species also possess long centromeres. Our results are consistent with a model of simple runaway centromere expansion due to centromere drive. We suggest expanded centromeres may be more prevalent in hymenopteran insects, which use haplodiploid sex determination, than previously considered.

  19. Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

    NASA Astrophysics Data System (ADS)

    Matsuura, Kenji; Yashiro, Toshihisa

    2006-10-01

    Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

  20. Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus.

    PubMed

    Matsuura, Kenji; Yashiro, Toshihisa

    2006-10-01

    Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

  1. Current and potential ant impacts in the Pacific region

    USGS Publications Warehouse

    Loope, Lloyd L.; Krushelnycky, Paul D.

    2007-01-01

    Worldwide, ants are a powerful ecological force, and they appear to be dominant components of animal communities of many tropical and temperate ecosystems in terms of biomass and numbers of individuals (Bluthgen et al. 2000). For example, ants comprise up to 94% of arthropod individuals in fogging samples taken from diverse lowland tropical rainforest canopies, and 86% of the biomass (Davidson et al. 2003). The majority of these ant species and individuals obtain carbohydrates either from extrafloral nectaries or from sap-feeding Hemiptera that pass carbohydrate-rich “honeydew” to attending ants while concentrating nitrogen (N) from N-poor plant sap (Davidson et al. 2003). Honeydew and nectar represent key resources for arboreal ant species, although most ant species are at least partly carnivorous or scavengers (Bluthgen et al. 2004). In contrast to most of the terrestrial world, the biotas of many Pacific islands evolved without ants. Whereas endemic ant species are found in New Zealand (ca. 10 spp.), Tonga (ca. 10 spp.), and Samoa (ca. 12 spp.), other islands of Polynesia and parts of Micronesia likely lack native ants (Wilson and Taylor 1967, Wetterer 2002, Wetterer and Vargo 2003). About 20 Indo-Australian and western Pacific ant species range to the east and north of Samoa, but it is unclear how many of these were transported there by humans at some time (Wilson and Taylor 1967). Most of the remainder of the ant species currently found on Pacific islands are widespread species that fall in the category of “tramp species,” dispersed by recent human commerce and generally closely tied to human activity and urban areas (Wilson and Taylor 1967, McGlynn 1999). In Pacific island situations, some of these tramp ant species are able to thrive beyond areas of human activity. Relatively few ant species have been successful invaders of native communities on continents, and these include most of the species that pose the greatest problems for Pacific islands

  2. Horned lizards (Phrynosoma) incapacitate dangerous ant prey with mucus.

    PubMed

    Sherbrooke, Wade C; Schwenk, Kurt

    2008-10-01

    Horned lizards (Iguanidae, Phrynosomatinae, Phrynosoma) are morphologically specialized reptiles characterized by squat, tank-like bodies, short limbs, blunt snouts, spines and cranial horns, among other traits. They are unusual among lizards in the degree to which they specialize on a diet of ants, but exceptional in the number of pugnacious, highly venomous, stinging ants they consume, especially harvester ants (genus Pogonomyrmex). Like other iguanian lizards, they capture insect prey on the tongue, but unlike other lizards, they neither bite nor chew dangerous prey before swallowing. Instead, they employ a unique kinematic pattern in which prey capture, transport and swallowing are combined. Nevertheless, horned lizards consume dozens of harvester ants without harm. We show that their derived feeding kinematics are associated with unique, mucus-secreting pharyngeal papillae that apparently serve to immobilize and incapacitate dangerous ants as they are swallowed by compacting them and binding them in mucus strands. Radially branched esophageal folds provide additional mucus-secreting surfaces the ants pass through as they are swallowed. Ants extracted from fresh-killed horned lizard stomachs are curled ventrally into balls and bound in mucus. We conclude that the pharyngeal papillae, in association with a unique form of hyolingual prey transport and swallowing, are horned lizard adaptations related to a diet of dangerous prey. Harvester ant defensive weapons, along with horned lizard adaptations against such weapons, suggest a long-term, predator-prey, co-evolutionary arms race between Phrynosoma and Pogonomyrmex. Copyright 2008 Wiley-Liss, Inc.

  3. Chaos-order transition in foraging behavior of ants.

    PubMed

    Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

    2014-06-10

    The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques. Biologists have discovered that single ants exhibit low-dimensional deterministic-chaotic activities. However, the influences of the nest, ants' physical abilities, and ants' knowledge (or experience) on foraging behavior have received relatively little attention in studies of the collective behavior of ants. This paper provides new insights into basic mechanisms of effective foraging for social insects or group animals that have a home. We propose that the whole foraging process of ants is controlled by three successive strategies: hunting, homing, and path building. A mathematical model is developed to study this complex scheme. We show that the transition from chaotic to periodic regimes observed in our model results from an optimization scheme for group animals with a home. According to our investigation, the behavior of such insects is not represented by random but rather deterministic walks (as generated by deterministic dynamical systems, e.g., by maps) in a random environment: the animals use their intelligence and experience to guide them. The more knowledge an ant has, the higher its foraging efficiency is. When young insects join the collective to forage with old and middle-aged ants, it benefits the whole colony in the long run. The resulting strategy can even be optimal.

  4. The genome of the fire ant Solenopsis invicta

    USDA-ARS?s Scientific Manuscript database

    Ants have evolved very complex societies and are key ecosystem members. Some of them are also major pests, as exemplified by the fire ant Solenopsis invicta. We present here the draft genome of S. invicta, assembled from 454 and Illumina reads obtained from a focal haploid male and his brothers. In ...

  5. Ant and termite predation by the tropical blindsnake Typhlops platycephalus

    Treesearch

    J.A. Torres; R. Thomas; M. Leal; T. Gush

    2000-01-01

    Dietary habits of the Puerto Rican blindsnake Typhlops platycephalus were studied by analysis of gastrointestinal tract contents and scats. Ant species (the principal prey taxon) were surveyed concurrently with the collection of the blindsnakes to determine what proportion of the species were used as prey. Typhlops platycephalus fed on 14 of 30 ant species found in the...

  6. Mastracchio works with the Ant Forage Habitat Facility

    NASA Image and Video Library

    2014-01-13

    ISS038-E-031992 (13 Jan. 2014) --- NASA astronaut Rick Mastracchio, Expedition 38 flight engineer, works with the Ant Forage Habitat Facility in the Destiny laboratory of the International Space Station. The study examines the behavior of ants by comparing groups living on Earth to those in space.

  7. Tracing the Rise of Ants - Out of the Ground

    PubMed Central

    Lucky, Andrea; Trautwein, Michelle D.; Guénard, Benoit S.; Weiser, Michael D.; Dunn, Robert R.

    2013-01-01

    The evolution of ants (Hymenoptera: Formicidae) is increasingly well-understood due to recent phylogenetic analyses, along with estimates of divergence times and diversification rates. Yet, leading hypotheses regarding the ancestral habitat of ants conflict with new findings that early ant lineages are cryptic and subterranean. Where the ants evolved, in respect to habitat, and how habitat shifts took place over time have not been formally tested. Here, we reconstruct the habitat transitions of crown-group ants through time, focusing on where they nest and forage (in the canopy, litter, or soil). Based on ancestral character reconstructions, we show that in contrast to the current consensus based on verbal arguments that ants evolved in tropical leaf litter, the soil is supported as the ancestral stratum of all ants. We also find subsequent movements up into the litter and, in some cases, into the canopy. Given the global importance of ants, because of their diversity, ecological influence and status as the most successful eusocial lineage on Earth, understanding the early evolution of this lineage provides insight into the factors that made this group so successful today. PMID:24386323

  8. Foraging distance of the Argentine ant in California vineyards

    USDA-ARS?s Scientific Manuscript database

    Argentine ants, Linepithema humile (Mayr), form mutualisms with hemipteran pests in crop systems. In vineyards, they feed on honeydew produced by mealybugs and soft scales, which they tend and protect from natural enemies. Few options for controlling Argentine ants are available; one of the more eff...

  9. ANT COMMUNITIES AND LIVESTOCK GRAZING IN THE GREAT BASIN, USA

    EPA Science Inventory

    The objectives of this study were to determine if metrics for ant species assemblages can be used as indicators of rangeland condition, and to determine the influence of vegetation and ground cover variables, factors often influenced by livestock grazing, on ant communities. The ...

  10. Odorous House Ants (Tapinoma sessile) as Back-Seat Drivers of Localized Ant Decline in Urban Habitats

    PubMed Central

    Salyer, Adam; Bennett, Gary W.; Buczkowski, Grzegorz A.

    2014-01-01

    Invasive species and habitat disturbance threaten biodiversity worldwide by modifying ecosystem performance and displacing native organisms. Similar homogenization impacts manifest locally when urbanization forces native species to relocate or reinvade perpetually altered habitat. This study investigated correlations between ant richness and abundance in response to urbanization and the nearby presence of invasive ant species, odorous house ants (Tapinoma sessile), within its native region. Surveying localized ant composition within natural, semi-natural, and urban habitat supported efforts to determine whether T. sessile appear to be primary (drivers) threats as instigators or secondary (passengers) threats as inheritors of indigenous ant decline. Sampling 180 sites, evenly split between all habitats with and without T. sessile present, yielded 45 total species. Although urbanization and T. sessile presence factors were significantly linked to ant decline, their interaction correlated to the greatest reduction of total ant richness (74%) and abundance (81%). Total richness appeared to decrease from 27 species to 18 when natural habitat is urbanized and from 18 species to 7 with T. sessile present in urban plots. Odorous house ant presence minimally influenced ant communities within natural and semi-natural habitat, highlighting the importance of habitat alteration and T. sessile presence interactions. Results suggest urbanization releases T. sessile from unknown constraints by decreasing ant richness and competition. Within urban environment, T. sessile are pre-adapted to quickly exploit new resources and grow to supercolony strength wherein T. sessile drive adjacent biodiversity loss. Odorous house ants act as passengers and drivers of ecological change throughout different phases of urban ‘invasion’. This progression through surviving habitat alteration, exploiting new resources, thriving, and further reducing interspecific competition supports a

  11. The rise of army ants and their relatives: diversification of specialized predatory doryline ants

    PubMed Central

    2014-01-01

    Background Army ants are dominant invertebrate predators in tropical and subtropical terrestrial ecosystems. Their close relatives within the dorylomorph group of ants are also highly specialized predators, although much less is known about their biology. We analyzed molecular data generated from 11 nuclear genes to infer a phylogeny for the major dorylomorph lineages, and incorporated fossil evidence to infer divergence times under a relaxed molecular clock. Results Because our results indicate that one subfamily and several genera of dorylomorphs are non-monophyletic, we propose to subsume the six previous dorylomorph subfamilies into a single subfamily, Dorylinae. We find the monophyly of Dorylinae to be strongly supported and estimate the crown age of the group at 87 (74–101) million years. Our phylogenetic analyses provide only weak support for army ant monophyly and also call into question a previous hypothesis that army ants underwent a fundamental split into New World and Old World lineages. Outside the army ants, our phylogeny reveals for the first time many old, distinct lineages in the Dorylinae. The genus Cerapachys is shown to be non-monophyletic and comprised of multiple lineages scattered across the Dorylinae tree. We recover, with strong support, novel relationships among these Cerapachys-like clades and other doryline genera, but divergences in the deepest parts of the tree are not well resolved. We find the genus Sphinctomyrmex, characterized by distinctive abdominal constrictions, to consist of two separate lineages with convergent morphologies, one inhabiting the Old World and the other the New World tropics. Conclusions While we obtain good resolution in many parts of the Dorylinae phylogeny, relationships deep in the tree remain unresolved, with major lineages joining each other in various ways depending upon the analytical method employed, but always with short internodes. This may be indicative of rapid radiation in the early history of

  12. Improved Ant Algorithms for Software Testing Cases Generation

    PubMed Central

    Yang, Shunkun; Xu, Jiaqi

    2014-01-01

    Existing ant colony optimization (ACO) for software testing cases generation is a very popular domain in software testing engineering. However, the traditional ACO has flaws, as early search pheromone is relatively scarce, search efficiency is low, search model is too simple, positive feedback mechanism is easy to porduce the phenomenon of stagnation and precocity. This paper introduces improved ACO for software testing cases generation: improved local pheromone update strategy for ant colony optimization, improved pheromone volatilization coefficient for ant colony optimization (IPVACO), and improved the global path pheromone update strategy for ant colony optimization (IGPACO). At last, we put forward a comprehensive improved ant colony optimization (ACIACO), which is based on all the above three methods. The proposed technique will be compared with random algorithm (RND) and genetic algorithm (GA) in terms of both efficiency and coverage. The results indicate that the improved method can effectively improve the search efficiency, restrain precocity, promote case coverage, and reduce the number of iterations. PMID:24883391

  13. Egg-laying butterflies distinguish predaceous ants by sight.

    PubMed

    Sendoya, Sebastián F; Freitas, André V L; Oliveira, Paulo S

    2009-07-01

    Information about predation risks is critical for herbivorous insects, and natural selection favors their ability to detect predators before oviposition and to select enemy-free foliage when offspring mortality risk is high. Food plants are selected by ovipositing butterflies, and offspring survival frequently varies among plants because of variation in the presence of predators. Eunica bechina butterflies oviposit on Caryocar brasiliense, an ant-defended plant. Experiments with dried Camponotus and Cephalotes ants pinned to leaves revealed that butterflies use ant size and form as visual cues to avoid ovipositing on plant parts occupied by ants more likely to kill larval offspring. Presence of sap-sucking bugs did not affect butterfly oviposition. This is the first demonstration that visual recognition of predators can mediate egg-laying decisions by an insect herbivore and that an insect will discriminate among different species of potential predators. This unusual behavioral capability permits specialization on a risky, ant-defended food plant.

  14. Endophytic fungi reduce leaf-cutting ant damage to seedlings

    PubMed Central

    Bittleston, L. S.; Brockmann, F.; Wcislo, W.; Van Bael, S. A.

    2011-01-01

    Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high (Ehigh) or low (Elow) densities of endophytes. The Ehigh seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the Elow treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from Elow relative to Ehigh seedlings and had a tendency to recruit more ants to Elow plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities. PMID:20610420

  15. Competition between harvester ants and rodents in the cold desert

    SciTech Connect

    Landeen, D.S.; Jorgensen, C.D.; Smith, H.D.

    1979-09-30

    Local distribution patterns of three rodent species (Perognathus parvus, Peromyscus maniculatus, Reithrodontomys megalotis) were studied in areas of high and low densities of harvester ants (Pogonomyrmex owyheei) in Raft River Valley, Idaho. Numbers of rodents were greatest in areas of high ant-density during May, but partially reduced in August; whereas, the trend was reversed in areas of low ant-density. Seed abundance was probably not the factor limiting changes in rodent populations, because seed densities of annual plants were always greater in areas of high ant-density. Differences in seasonal population distributions of rodents between areas of high and low ant-densities weremore » probably due to interactions of seed availability, rodent energetics, and predation.« less

  16. SMART Power Systems for ANTS Missions

    NASA Astrophysics Data System (ADS)

    Clark, P. E.; Floyd, S. R.; Curtis, S. A.; Rilee, M. L.

    2005-02-01

    Autonomous NanoTechnology Swarm (ANTS) Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full spectrum of activities in space. ART systems based on currently available electromechanical (EMS) technology could support human crews on the lunar surface within the next 10 to 15 years. Two or more decades from now, NEMS (Super Miniaturized ART or SMART) technology could perform fully autonomous surveys and operations beyond the reach of human crews. Power system requirements would range from 1 kg to generate tens of Watts for near term ART applications, such as a lunar or Mars Lander Amorphous Rover Antenna (LARA), to <0.1 kg to generate hundreds of mWatts for more advanced SMART applications.

  17. Task partitioning in a ponerine ant.

    PubMed

    Theraulaz, Guy; Bonabeau, Eric; Sole, Ricard V; Schatz, Bertrand; Deneubourg, Jean-Louis

    2002-04-21

    This paper reports a study of the task partitioning observed in the ponerine ant Ectatomma ruidum, where prey-foraging behaviour can be subdivided into two categories: stinging and transporting. Stingers kill live prey and transporters carry prey corpses back to the nest. Stinging and transporting behaviours are released by certain stimuli through response thresholds; the respective stimuli for stinging and transporting appear to be the number of live prey and the number of prey corpses. A response threshold model, the parameters of which are all measured empirically, reproduces a set of non-trivial colony-level dynamical patterns observed in the experiments. This combination of modelling and empirical work connects explicitly the level of individual behaviour with colony-level patterns of work organization. Copyright 2002 Elsevier Science Ltd. All rights reserved.

  18. Ex-Ante Beleidsevaluatie met System Dynamics (Ex-Ante Policy at System Dynamics)

    DTIC Science & Technology

    2008-03-01

    11 . van TFighciho,, cn. [DMO-11cleid 0 Vastgestlid d.d. 13 inaart 2008 (Lkzc mnccmn ss, i/it miet) Tite Onigerubriceerd Managenicnadiurcksel O...genaamd, brengt beleidsopties en beleidsdoelen vastgesteld. oorzaken en gevolgen rondom een Daamna heeft TNO conform de MARVEL 4/62 Ex-ante...rapport I TNO-DV 2007 A055 TNO-rapport I TNO-DV 2007 A055 9 /62 Afkortingen BPO Business Process Ownership CDC/DCIVB Commando Diensten Centra / Diensten

  19. Auguste Forel on ants and neurology.

    PubMed

    Parent, André

    2003-08-01

    Auguste Forel was born in 1848 in the French part of Switzerland. He developed a lifelong passion for myrmecology in his childhood, but chose medicine and neuropsychiatry to earn his living. He first undertook a comparative study of the thalamus under Theodor Meynert in Vienna and then, from 1872 to 1879, he worked as Assistant Physician to Bernhard von Gudden in Munich. This led in 1877 to his seminal work on the organization of the tegmental region in which he provides the first description of the zona incerta and the so-called H (Haubenfeld) fields that still bear his name. In 1879, Forel was appointed Professor of Psychiatry in Munich and Director of the Burghölzli cantonal asylum. He became interested in the therapeutic value of hypnotism, while continuing his work on brain anatomy and ants. His neuroanatomical studies with Gudden's method led him to formulate the neuron theory in 1887, four years before Wilhelm von Waldeyer, who received most of the credit for it. Forel then definitively turned his back on neuroscience. After his retirement from the Burghölzli asylum in 1898. and despite a stroke in 1911 that left him hemiplegic, Forel started to write extensively on various social issues, such as alcohol abstinence and sexual problems. Before his death in 1931 at the age of 83, Forel published a remarkable book on the social world of the ants in which he made insightful observations on the neural control of sensory and instinctive behavior common to both humans and insects.

  20. Overview of the Distribution, Habitat Association and Impact of Exotic Ants on Native Ant Communities in New Caledonia

    PubMed Central

    Berman, Maïa; Andersen, Alan N.; Hély, Christelle; Gaucherel, Cédric

    2013-01-01

    Ants are among the most ubiquitous and harmful invaders worldwide, but there are few regional studies of their relationships with habitat and native ant communities. New Caledonia has a unique and diverse ant fauna that is threatened by exotic ants, but broad-scale patterns of exotic and native ant community composition in relation to habitat remain poorly documented. We conducted a systematic baiting survey of 56 sites representing the main New Caledonian habitat types: rainforest on ultramafic soils (15 sites), rainforest on volcano-sedimentary soils (13), maquis shrubland (15), Melaleuca-dominated savannas (11) and Acacia spirorbis thickets (2). We collected a total of 49 species, 13 of which were exotic. Only five sites were free of exotic species, and these were all rainforest. The five most abundant exotic species differed in their habitat association, with Pheidole megacephala associated with rainforests, Brachymyrmex cf. obscurior with savanna, and Wasmannia auropunctata and Nylanderia vaga present in most habitats. Anoplolepis gracilipes occurred primarily in maquis-shrubland, which contrasts with its rainforest affinity elsewhere. Multivariate analysis of overall ant species composition showed strong differentiation of sites according to the distribution of exotic species, and these patterns were maintained at the genus and functional group levels. Native ant composition differed at invaded versus uninvaded rainforest sites, in the absence of differences in habitat variables. Generalised Myrmicinae and Forest Opportunists were particularly affected by invasion. There was a strong negative relationship between the abundance of W. auropunctata and native ant abundance and richness. This emphasizes that, in addition to dominating many ant communities numerically, some exotic species, and in particular W. auropunctata, have a marked impact on native ant communities. PMID:23840639

  1. Wasps robbing food from ants: a frequent behavior?

    NASA Astrophysics Data System (ADS)

    Lapierre, Louis; Hespenheide, Henry; Dejean, Alain

    2007-12-01

    Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes. (1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more common than previously thought.

  2. Ant-mediated seed dispersal in a warmed world

    PubMed Central

    Patterson, Courtney M.; Rodriguez-Cabal, Mariano A.; Ribbons, Relena R.; Dunn, Robert R.; Sanders, Nathan J.

    2014-01-01

    Climate change affects communities both directly and indirectly via changes in interspecific interactions. One such interaction that may be altered under climate change is the ant-plant seed dispersal mutualism common in deciduous forests of eastern North America. As climatic warming alters the abundance and activity levels of ants, the potential exists for shifts in rates of ant-mediated seed dispersal. We used an experimental temperature manipulation at two sites in the eastern US (Harvard Forest in Massachusetts and Duke Forest in North Carolina) to examine the potential impacts of climatic warming on overall rates of seed dispersal (using Asarum canadense seeds) as well as species-specific rates of seed dispersal at the Duke Forest site. We also examined the relationship between ant critical thermal maxima (CTmax) and the mean seed removal temperature for each ant species. We found that seed removal rates did not change as a result of experimental warming at either study site, nor were there any changes in species-specific rates of seed dispersal. There was, however, a positive relationship between CTmax and mean seed removal temperature, whereby species with higher CTmax removed more seeds at hotter temperatures. The temperature at which seeds were removed was influenced by experimental warming as well as diurnal and day-to-day fluctuations in temperature. Taken together, our results suggest that while temperature may play a role in regulating seed removal by ants, ant plant seed-dispersal mutualisms may be more robust to climate change than currently assumed. PMID:24688863

  3. Stridulations Reveal Cryptic Speciation in Neotropical Sympatric Ants

    PubMed Central

    Ferreira, Ronara Souza; Poteaux, Chantal; Delabie, Jacques Hubert Charles; Fresneau, Dominique; Rybak, Fanny

    2010-01-01

    The taxonomic challenge posed by cryptic species underlines the importance of using multiple criteria in species delimitation. In the current paper we tested the use of acoustic analysis as a tool to assess the real diversity in a cryptic species complex of Neotropical ants. In order to understand the potential of acoustics and to improve consistency in the conclusions by comparing different approaches, phylogenetic relationships of all the morphs considered were assessed by the analysis of a fragment of the mitochondrial DNA cytochrome b. We observed that each of the cryptic morph studied presents a morphologically distinct stridulatory organ and that all sympatric morphs produce distinctive stridulations. This is the first evidence of such a degree of specialization in the acoustic organ and signals in ants, which suggests that stridulations may be among the cues used by these ants during inter-specific interactions. Mitochondrial DNA variation corroborated the acoustic differences observed, confirming acoustics as a helpful tool to determine cryptic species in this group of ants, and possibly in stridulating ants in general. Congruent morphological, acoustic and genetic results constitute sufficient evidence to propose each morph studied here as a valid new species, suggesting that P. apicalis is a complex of at least 6 to 9 species, even if they present different levels of divergence. Finally, our results highlight that ant stridulations may be much more informative than hitherto thought, as much for ant communication as for integrative taxonomists. PMID:21203529

  4. Newly discovered sister lineage sheds light on early ant evolution.

    PubMed

    Rabeling, Christian; Brown, Jeremy M; Verhaagh, Manfred

    2008-09-30

    Ants are the world's most conspicuous and important eusocial insects and their diversity, abundance, and extreme behavioral specializations make them a model system for several disciplines within the biological sciences. Here, we report the discovery of a new ant that appears to represent the sister lineage to all extant ants (Hymenoptera: Formicidae). The phylogenetic position of this cryptic predator from the soils of the Amazon rainforest was inferred from several nuclear genes, sequenced from a single leg. Martialis heureka (gen. et sp. nov.) also constitutes the sole representative of a new, morphologically distinct subfamily of ants, the Martialinae (subfam. nov.). Our analyses have reduced the likelihood of long-branch attraction artifacts that have troubled previous phylogenetic studies of early-diverging ants and therefore solidify the emerging view that the most basal extant ant lineages are cryptic, hypogaeic foragers. On the basis of morphological and phylogenetic evidence we suggest that these specialized subterranean predators are the sole surviving representatives of a highly divergent lineage that arose near the dawn of ant diversification and have persisted in ecologically stable environments like tropical soils over great spans of time.

  5. Cotton Rats Alter Foraging in Response to an Invasive Ant.

    PubMed

    Darracq, Andrea K; Conner, L Mike; Brown, Joel S; McCleery, Robert A

    We assessed the effects of red imported fire ants (Solenopsis invicta; hereafter fire ant) on the foraging of hispid cotton rats (Sigmodon hispidus). We used a manipulative experiment, placing resource patches with a known amount of millet seed within areas with reduced (RIFA [-]) or ambient (RIFA [+]) numbers of fire ants. We measured giving up densities (the amount of food left within each patch) within the resource patches for 4 days to quantify the effects of fire ants on cotton rat foraging. We assessed the effects of fire ant treatment (RIFA), Day, and their interaction on cotton rat giving up densities. Giving up densities on RIFA [+] grids were nearly 2.2 times greater across all foraging days and ranged from 1.6 to 2.3 times greater from day 1 to day 4 than the RIFA [-] grids. From day 1 to day 4, mean giving up densities decreased significantly faster for the RIFA [-] than RIFA [+] treatments, 58% and 13%, respectively. Our results demonstrate that cotton rats perceive a risk of injury from fire ants, which is likely caused by interference competition, rather than direct predation. Envenomation from ants likely decrease the foraging efficiency of cotton rats resulting in more time spent foraging. Increased time spent foraging is likely stressful in terms of the opportunity for direct injury and encounters with other predators. These indirect effects may reduce an individual cotton rat's fitness and translate into lowered population abundances.

  6. Cotton Rats Alter Foraging in Response to an Invasive Ant

    PubMed Central

    Darracq, Andrea K.; Conner, L. Mike; Brown, Joel S.; McCleery, Robert A.

    2016-01-01

    We assessed the effects of red imported fire ants (Solenopsis invicta; hereafter fire ant) on the foraging of hispid cotton rats (Sigmodon hispidus). We used a manipulative experiment, placing resource patches with a known amount of millet seed within areas with reduced (RIFA [–]) or ambient (RIFA [+]) numbers of fire ants. We measured giving up densities (the amount of food left within each patch) within the resource patches for 4 days to quantify the effects of fire ants on cotton rat foraging. We assessed the effects of fire ant treatment (RIFA), Day, and their interaction on cotton rat giving up densities. Giving up densities on RIFA [+] grids were nearly 2.2 times greater across all foraging days and ranged from 1.6 to 2.3 times greater from day 1 to day 4 than the RIFA [–] grids. From day 1 to day 4, mean giving up densities decreased significantly faster for the RIFA [–] than RIFA [+] treatments, 58% and 13%, respectively. Our results demonstrate that cotton rats perceive a risk of injury from fire ants, which is likely caused by interference competition, rather than direct predation. Envenomation from ants likely decrease the foraging efficiency of cotton rats resulting in more time spent foraging. Increased time spent foraging is likely stressful in terms of the opportunity for direct injury and encounters with other predators. These indirect effects may reduce an individual cotton rat’s fitness and translate into lowered population abundances. PMID:27655320

  7. Interactions Increase Forager Availability and Activity in Harvester Ants.

    PubMed

    Pless, Evlyn; Queirolo, Jovel; Pinter-Wollman, Noa; Crow, Sam; Allen, Kelsey; Mathur, Maya B; Gordon, Deborah M

    2015-01-01

    Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.

  8. Newly discovered sister lineage sheds light on early ant evolution

    PubMed Central

    Rabeling, Christian; Brown, Jeremy M.; Verhaagh, Manfred

    2008-01-01

    Ants are the world's most conspicuous and important eusocial insects and their diversity, abundance, and extreme behavioral specializations make them a model system for several disciplines within the biological sciences. Here, we report the discovery of a new ant that appears to represent the sister lineage to all extant ants (Hymenoptera: Formicidae). The phylogenetic position of this cryptic predator from the soils of the Amazon rainforest was inferred from several nuclear genes, sequenced from a single leg. Martialis heureka (gen. et sp. nov.) also constitutes the sole representative of a new, morphologically distinct subfamily of ants, the Martialinae (subfam. nov.). Our analyses have reduced the likelihood of long-branch attraction artifacts that have troubled previous phylogenetic studies of early-diverging ants and therefore solidify the emerging view that the most basal extant ant lineages are cryptic, hypogaeic foragers. On the basis of morphological and phylogenetic evidence we suggest that these specialized subterranean predators are the sole surviving representatives of a highly divergent lineage that arose near the dawn of ant diversification and have persisted in ecologically stable environments like tropical soils over great spans of time. PMID:18794530

  9. Effect of Interactions between Harvester Ants on Forager Decisions

    PubMed Central

    Davidson, Jacob D.; Arauco-Aliaga, Roxana P.; Crow, Sam; Gordon, Deborah M.; Goldman, Mark S.

    2017-01-01

    Harvester ant colonies adjust their foraging activity to day-to-day changes in food availability and hour-to-hour changes in environmental conditions. This collective behavior is regulated through interactions, in the form of brief antennal contacts, between outgoing foragers and returning foragers with food. Here we consider how an ant, waiting in the entrance chamber just inside the nest entrance, uses its accumulated experience of interactions to decide whether to leave the nest to forage. Using videos of field observations, we tracked the interactions and foraging decisions of ants in the entrance chamber. Outgoing foragers tended to interact with returning foragers at higher rates than ants that returned to the deeper nest and did not forage. To provide a mechanistic framework for interpreting these results, we develop a decision model in which ants make decisions based upon a noisy accumulation of individual contacts with returning foragers. The model can reproduce core trends and realistic distributions for individual ant interaction statistics, and suggests possible mechanisms by which foraging activity may be regulated at an individual ant level. PMID:28758093

  10. Collective strategy for obstacle navigation during cooperative transport by ants.

    PubMed

    McCreery, Helen F; Dix, Zachary A; Breed, Michael D; Nagpal, Radhika

    2016-11-01

    Group cohesion and consensus have primarily been studied in the context of discrete decisions, but some group tasks require making serial decisions that build on one another. We examine such collective problem solving by studying obstacle navigation during cooperative transport in ants. In cooperative transport, ants work together to move a large object back to their nest. We blocked cooperative transport groups of Paratrechina longicornis with obstacles of varying complexity, analyzing groups' trajectories to infer what kind of strategy the ants employed. Simple strategies require little information, but more challenging, robust strategies succeed with a wider range of obstacles. We found that transport groups use a stochastic strategy that leads to efficient navigation around simple obstacles, and still succeeds at difficult obstacles. While groups navigating obstacles preferentially move directly toward the nest, they change their behavior over time; the longer the ants are obstructed, the more likely they are to move away from the nest. This increases the chance of finding a path around the obstacle. Groups rapidly changed directions and rarely stalled during navigation, indicating that these ants maintain consensus even when the nest direction is blocked. Although some decisions were aided by the arrival of new ants, at many key points, direction changes were initiated within the group, with no apparent external cause. This ant species is highly effective at navigating complex environments, and implements a flexible strategy that works for both simple and more complex obstacles. © 2016. Published by The Company of Biologists Ltd.

  11. Interactions Increase Forager Availability and Activity in Harvester Ants

    PubMed Central

    Pinter-Wollman, Noa; Crow, Sam; Allen, Kelsey; Mathur, Maya B.; Gordon, Deborah M.

    2015-01-01

    Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated. PMID:26539724

  12. Contact rate modulates foraging efficiency in leaf cutting ants.

    PubMed

    Bouchebti, S; Ferrere, S; Vittori, K; Latil, G; Dussutour, A; Fourcassié, V

    2015-12-21

    Lane segregation is rarely observed in animals that move in bidirectional flows. Consequently, these animals generally experience a high rate of head-on collisions during their journeys. Although these collisions have a cost (each collision induces a delay resulting in a decrease of individual speed), they could also have a benefit by promoting information transfer between individuals. Here we explore the impact of head-on collisions in leaf-cutting ants moving on foraging trails by artificially decreasing the rate of head-on collisions between individuals. We show that head-on collisions do not influence the rate of recruitment in these ants but do influence foraging efficiency, i.e. the proportion of ants returning to the nest with a leaf fragment. Surprisingly, both unladen and laden ants returning to the nest participate in the modulation of foraging efficiency: foraging efficiency decreases when the rate of contacts with both nestbound laden or unladen ants decreases. These results suggest that outgoing ants are able to collect information from inbound ants even when these latter do not carry any leaf fragment and that this information can influence their foraging decisions when reaching the end of the trail.

  13. Species richness, equitability, and abundance of ants in disturbed landscapes

    USGS Publications Warehouse

    Graham, J.H.; Krzysik, A.J.; Kovacic, D.A.; Duda, J.J.; Freeman, D.C.; Emlen, J.M.; Zak, J.C.; Long, W.R.; Wallace, M.P.; Chamberlin-Graham, C.; Nutter, J.P.; Balbach, H.E.

    2009-01-01

    Ants are used as indicators of environmental change in disturbed landscapes, often without adequate understanding of their response to disturbance. Ant communities in the southeastern United States displayed a hump-backed species richness curve against an index of landscape disturbance. Forty sites at Fort Benning, in west-central Georgia, covered a spectrum of habitat disturbance (military training and fire) in upland forest. Sites disturbed by military training had fewer trees, less canopy cover, more bare ground, and warmer, more compact soils with shallower A-horizons. We sampled ground-dwelling ants with pitfall traps, and measured 15 habitat variables related to vegetation and soil. Ant species richness was greatest with a relative disturbance of 43%, but equitability was greatest with no disturbance. Ant abundance was greatest with a relative disturbance of 85%. High species richness at intermediate disturbance was associated with greater within-site spatial heterogeneity. Species richness was also associated with intermediate values of the normalized difference vegetation index (NDVI), a correlate of net primary productivity (NPP). Available NPP (the product of NDVI and the fraction of days that soil temperature exceeded 25 ??C), however, was positively correlated with species richness, though not with ant abundance. Species richness was unrelated to soil texture, total ground cover, and fire frequency. Ant species richness and equitability are potential state indicators of the soil arthropod community. Moreover, equitability can be used to monitor ecosystem change. ?? 2008 Elsevier Ltd.

  14. Plant defense, herbivory, and the growth of Cordia alliodora trees and their symbiotic Azteca ant colonies.

    PubMed

    Pringle, Elizabeth G; Dirzo, Rodolfo; Gordon, Deborah M

    2012-11-01

    The effects of herbivory on plant fitness are integrated over a plant's lifetime, mediated by ontogenetic changes in plant defense, tolerance, and herbivore pressure. In symbiotic ant-plant mutualisms, plants provide nesting space and food for ants, and ants defend plants against herbivores. The benefit to the plant of sustaining the growth of symbiotic ant colonies depends on whether defense by the growing ant colony outpaces the plant's growth in defendable area and associated herbivore pressure. These relationships were investigated in the symbiotic mutualism between Cordia alliodora trees and Azteca pittieri ants in a Mexican tropical dry forest. As ant colonies grew, worker production remained constant relative to ant-colony size. As trees grew, leaf production increased relative to tree size. Moreover, larger trees hosted lower densities of ants, suggesting that ant-colony growth did not keep pace with tree growth. On leaves with ants experimentally excluded, herbivory per unit leaf area increased exponentially with tree size, indicating that larger trees experienced higher herbivore pressure per leaf area than smaller trees. Even with ant defense, herbivory increased with tree size. Therefore, although larger trees had larger ant colonies, ant density was lower in larger trees, and the ant colonies did not provide sufficient defense to compensate for the higher herbivore pressure in larger trees. These results suggest that in this system the tree can decrease herbivory by promoting ant-colony growth, i.e., sustaining space and food investment in ants, as long as the tree continues to grow.

  15. Experimental evidence that the introduced fire ant, Solenopsis invicta, does not competitively suppress co-occurring ants in a disturbed habitat.

    PubMed

    King, Joshua R; Tschinkel, Walter R

    2006-11-01

    1. The fire ant, Solenopsis invicta, is a globally distributed invasive ant that is largely restricted to disturbed habitats in its introduced range. For more than half a century, biologists have believed its success results from superior competitive abilities relative to native ant species, as well as an escape from their natural enemies. 2. We used large volumes of hot water to kill fire ant colonies, and only fire ant colonies, on experimental plots in pastures, and found that populations and diversity of co-occurring ants did not subsequently increase. 3. These results are contrary to classical predictions and indicate that S. invicta is not a superior competitor that suppresses native ants, and that the low diversity and abundance of native ants in degraded ecosystems does not result from interaction with fire ants. Instead, other factors such as prior disturbance and recruitment limitation may be the primary limiting factors for native species in these habitats.

  16. Trail pheromone disruption of red imported fire ant.

    PubMed

    Suckling, David M; Stringer, Lloyd D; Bunn, Barry; El-Sayed, Ashraf M; Vander Meer, Robert K

    2010-07-01

    The fire ant, Solenopsis invicta (Hymenoptera: Formicidae), is considered one of the most aggressive and invasive species in the world. Toxic bait systems are used widely for control, but they also affect non-target ant species and cannot be used in sensitive ecosystems such as organic farms and national parks. The fire ant uses recruitment pheromones to organize the retrieval of large food resources back to the colony, with Z,E-alpha-farnesene responsible for the orientation of workers along trails. We prepared Z,E-alpha-farnesene, (91% purity) from extracted E,E-alpha-farnesene and demonstrated disruption of worker trail orientation after presentation of an oversupply of this compound from filter paper point sources (30 microg). Trails were established between queen-right colony cells and food sources in plastic tubs. Trail-following behavior was recorded by overhead webcam, and ants were digitized before and after presentation of the treatment, using two software approaches. The linear regression statistic, r(2) was calculated. Ants initially showed high linear trail integrity (r(2) = 0.75). Within seconds of presentation of the Z,E-alpha-farnesene treatment, the trailing ants showed little or no further evidence of trail following behavior in the vicinity of the pheromone source. These results show that trailing fire ants become disorientated in the presence of large amounts of Z,E-alpha-farnesene. Disrupting fire ant recruitment to resources may have a negative effect on colony size or other effects yet to be determined. This phenomenon was demonstrated recently for the Argentine ant, where trails were disrupted for two weeks by using their formulated trail pheromone, Z-9-hexadecenal. Further research is needed to establish the long term effects and control potential for trail disruption in S. invicta.

  17. Weaver ant role in cashew orchards in Vietnam.

    PubMed

    Peng, Renkang; Lan, La Pham; Christian, Keith

    2014-08-01

    Cashew (Anacardium occidentale L.) is a very important source of income for more than 200,000 farmer households in Vietnam. The present cashew productivity in Vietnam is low and unstable, and pest damage is partly responsible for this. Cashew farmers rely on pesticides to minimize the damage, resulting in adverse impacts on farm environment and farmers' health. Weaver ants (Oecophylla spp) are effective biocontrol agents of a range of cashew insect pests in several cashew-growing countries, and these ants are widely distributed in Vietnam. The aim of this study is to evaluate the potential of weaver ants in cashew orchards in Vietnam. Field surveys and field experiment were conducted in five cashew orchards from July 2006 to January 2008 in Binh Phuoc, Dong Nai, and Ba Ria Vung Tau provinces, Vietnam. Based on the field surveys, the most important pests that damage flushing foliar and floral shoots and young cashew fruits and nuts were mosquito bugs, brown shoot borers, blue shoot borers, and fruit-nut borers. The damage caused by each of these pests was significantly lower on trees with weaver ants compared with trees without the ants, showing that the ants were able to keep these pest damages under the control threshold. Regular monitoring of the field experiment showed that weaver ants were similar to insecticides for controlling mosquito bugs, blue shoot borers, fruit-nut borers, leaf rollers, and leaf miners. Aphids did not become major pests in plot with weaver ants. To manage insect pest assemblage in cashew orchards, an integrated pest management using weaver ants as a major component is discussed.

  18. The ecological role of ants in two Mexican agroecosystems.

    PubMed

    Risch, Stephen J; Carroll, C Ronald

    1982-10-01

    The development of the ant communities and their foraging dynamics were studied in two annual agroecosystems of the Mexican tropical lowlands: a "forest milpa" of corn, beans, and squash made by cutting and buring 40-year-old forest, and a "field milpa" of corn, beans, and squash made by plowing 1-year-old second growth. The ant community was sampled using tuna fish baits 26, 52, 110 and 353 days after planting. Although immediately after planting the same number of ant species occurred in each milpa type, thereafter the ant faunas diverged. The field milpa became completely dominated by the native fire ant, Solenopsis geminata, while the number of ant species in the forest milpa gradually increased over time, reaching eight species 110 days after planting and 14 species by 353 days. Initially S. geminata dominated the ant fauna in the forest milpa (occurring on 90% of the baits), but by 353 days planting it was found on only 26% of the occupied baits. Ant foraging efficiency, as measured by proportion of tuna baits occupied and the removal rates of dead Drosophila fly baits, was much higher (by a factor of 2 to 3) in the field than the forest milpa. This was caused by the extremely high density of S. geminata colonies in the field milpa. The simple Solenopsis-dominated community of the field milpa may be much more effective in biological control than the more diverse community of the forest milpa. Although S. geminata has potential negative impacts in annual agroecosystems (it stings, eats corn seeds, and guards homopterams), its overall impact appears to be beneficial. As forested areas of the lowland wet tropics are increasingly cut and converted to annual agriculture, the primary ant inhabitant of these highly disturbed environments, S. geminata, will necessarily play a much more significant ecological role in agroecosystems.

  19. Ants of the national park of American Samoa

    USGS Publications Warehouse

    Banko, Paul C.; Peck, Robert W.

    2015-01-01

    American Samoa makes up the eastern end of the Samoan Archipelago. On the islands of Tutuila, Taʽū and Ofu, the National Park of American Samoa (NPSA) protects about 4,000 ha of coastal, mid-slope and ridge-top forest. While the ant fauna of the Samoan Archipelago is considered relatively well documented, much of NPSA has never been surveyed for ants, leaving the fauna and its distribution poorly known. To address this shortfall, we systematically surveyed ants within the Tutuila and Taʽū units of NPSA using standard methods (hand collecting, litter sifting, and baits) at 39 sites within six vegetation types ranging from 8 to 945 m elevation. Forty-four ant species were identified, 19 of which are exotic to the Samoan Archipelago. Two notoriously aggressive species, Anoplolepis gracilipes and Pheidole megacephala were detected at two and seven sites, respectively. Both of these species largely excluded all other ants from bait, although their impact on ant community composition is unclear. A suite of habitat variables measured at each site was assessed to explain park-wide ant distributions. Of eight variables evaluated, only elevation was associated with ant community structure, as the ratio of native to exotic ant species increased significantly with elevation on Tutuila. Our survey documented two species not previously reported from American Samoa. Strumigenys eggersi, detected at 12 sites, appears to be a new immigrant to the Pacific Basin. A species of Pheidole was collected that likely represents an undescribed species. Solenopsis geminata, an aggressive species first reported on Tutuila in 2002, was not detected during our survey.

  20. Warehouse stocking optimization based on dynamic ant colony genetic algorithm

    NASA Astrophysics Data System (ADS)

    Xiao, Xiaoxu

    2018-04-01

    In view of the various orders of FAW (First Automotive Works) International Logistics Co., Ltd., the SLP method is used to optimize the layout of the warehousing units in the enterprise, thus the warehouse logistics is optimized and the external processing speed of the order is improved. In addition, the relevant intelligent algorithms for optimizing the stocking route problem are analyzed. The ant colony algorithm and genetic algorithm which have good applicability are emphatically studied. The parameters of ant colony algorithm are optimized by genetic algorithm, which improves the performance of ant colony algorithm. A typical path optimization problem model is taken as an example to prove the effectiveness of parameter optimization.

  1. Desert ants achieve reliable recruitment across noisy interactions

    PubMed Central

    Razin, Nitzan; Eckmann, Jean-Pierre; Feinerman, Ofer

    2013-01-01

    We study how desert ants, Cataglyphis niger, a species that lacks pheromone-based recruitment mechanisms, inform each other about the presence of food. Our results are based on automated tracking that allows us to collect a large database of ant trajectories and interactions. We find that interactions affect an ant's speed within the nest. Fast ants tend to slow down, whereas slow ones increase their speed when encountering a faster ant. Faster ants tend to exit the nest more frequently than slower ones. So, if an ant gains enough speed through encounters with others, then she tends to leave the nest and look for food. On the other hand, we find that the probability for her to leave the nest depends only on her speed, but not on whether she had recently interacted with a recruiter that has found the food. This suggests a recruitment system in which ants communicate their state by very simple interactions. Based on this assumption, we estimate the information-theoretical channel capacity of the ants’ pairwise interactions. We find that the response to the speed of an interacting nest-mate is very noisy. The question is then how random interactions with ants within the nest can be distinguished from those interactions with a recruiter who has found food. Our measurements and model suggest that this distinction does not depend on reliable communication but on behavioural differences between ants that have found the food and those that have not. Recruiters retain high speeds throughout the experiment, regardless of the ants they interact with; non-recruiters communicate with a limited number of nest-mates and adjust their speed following these interactions. These simple rules lead to the formation of a bistable switch on the level of the group that allows the distinction between recruitment and random noise in the nest. A consequence of the mechanism we propose is a negative effect of ant density on exit rates and recruitment success. This is, indeed, confirmed by

  2. Ant colony algorithm for clustering in portfolio optimization

    NASA Astrophysics Data System (ADS)

    Subekti, R.; Sari, E. R.; Kusumawati, R.

    2018-03-01

    This research aims to describe portfolio optimization using clustering methods with ant colony approach. Two stock portfolios of LQ45 Indonesia is proposed based on the cluster results obtained from ant colony optimization (ACO). The first portfolio consists of assets with ant colony displacement opportunities beyond the defined probability limits of the researcher, where the weight of each asset is determined by mean-variance method. The second portfolio consists of two assets with the assumption that each asset is a cluster formed from ACO. The first portfolio has a better performance compared to the second portfolio seen from the Sharpe index.

  3. Selenium exposure results in reduced reproduction in an invasive ant species and altered competitive behavior for a native ant species.

    PubMed

    De La Riva, Deborah G; Trumble, John T

    2016-06-01

    Competitive ability and numerical dominance are important factors contributing to the ability of invasive ant species to establish and expand their ranges in new habitats. However, few studies have investigated the impact of environmental contamination on competitive behavior in ants as a potential factor influencing dynamics between invasive and native ant species. Here we investigated the widespread contaminant selenium to investigate its potential influence on invasion by the exotic Argentine ant, Linepithema humile, through effects on reproduction and competitive behavior. For the fecundity experiment, treatments were provided to Argentine ant colonies via to sugar water solutions containing one of three concentrations of selenium (0, 5 and 10 μg Se mL(-1)) that fall within the range found in soil and plants growing in contaminated areas. Competition experiments included both the Argentine ant and the native Dorymyrmex bicolor to determine the impact of selenium exposure (0 or 15 μg Se mL(-1)) on exploitation- and interference-competition between ant species. The results of the fecundity experiment revealed that selenium negatively impacted queen survival and brood production of Argentine ants. Viability of the developing brood was also affected in that offspring reached adulthood only in colonies that were not given selenium, whereas those in treated colonies died in their larval stages. Selenium exposure did not alter direct competitive behaviors for either species, but selenium exposure contributed to an increased bait discovery time for D. bicolor. Our results suggest that environmental toxins may not only pose problems for native ant species, but may also serve as a potential obstacle for establishment among exotic species. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Symbiotic mutualism with a community of opportunistic ants: protection, competition, and ant occupancy of the myrmecophyte Barteria nigritana (Passifloraceae)

    NASA Astrophysics Data System (ADS)

    Djiéto-Lordon, Champlain; Dejean, Alain; Gibernau, Marc; Hossaert-McKey, Martine; McKey, Doyle

    2004-10-01

    Barteria nigritana is a myrmecophyte tree of Lower Guinea coastal vegetation. Unlike the more specialised B. fistulosa, which harbours a single host-specific mutualistic ant, B. nigritana is associated with several opportunistic ants. Such symbiotic, yet opportunistic, ant-plant associations have been little studied. On 113 clumps of B. nigritana, we censused ant associates and herbivores and compared herbivory on plants occupied by different ants. In addition to these correlative data, protection conferred by different ant species was compared by herbivore-placement experiments. Identity of ant associate changed predictably over plant ontogeny. Pheidole megacephala was restricted to very small plants; saplings were occupied by either Oecophylla longinoda or Crematogaster sp., and the latter species was the sole occupant of larger trees. Damage by caterpillars of the nymphalid butterfly Acraea zetes accounted for much of the herbivory to leaves. Ant species differed in the protection provided to hosts. While P. megacephala provided no significant protection, plants occupied by O. longinoda and Crematogaster sp. suffered less damage than did unoccupied plants or those occupied by P. megacephala. Furthermore, O. longinoda provided more effective protection than did Crematogaster sp. Herbivore-placement experiments confirmed these results. Workers of O. longinoda killed or removed all larval instars of A. zetes. Crematogaster preyed on only the two first larval instars, and P. megacephala preyed mainly on eggs, only rarely attacking the two first larval instars. Opportunistic ants provided significant protection to this relatively unspecialised myrmecophyte. The usual associate of mature trees was not the species that provided most protection.

  5. Ant groups optimally amplify the effect of transiently informed individuals

    NASA Astrophysics Data System (ADS)

    Gelblum, Aviram; Pinkoviezky, Itai; Fonio, Ehud; Ghosh, Abhijit; Gov, Nir; Feinerman, Ofer

    2015-07-01

    To cooperatively transport a large load, it is important that carriers conform in their efforts and align their forces. A downside of behavioural conformism is that it may decrease the group's responsiveness to external information. Combining experiment and theory, we show how ants optimize collective transport. On the single-ant scale, optimization stems from decision rules that balance individuality and compliance. Macroscopically, these rules poise the system at the transition between random walk and ballistic motion where the collective response to the steering of a single informed ant is maximized. We relate this peak in response to the divergence of susceptibility at a phase transition. Our theoretical models predict that the ant-load system can be transitioned through the critical point of this mesoscopic system by varying its size; we present experiments supporting these predictions. Our findings show that efficient group-level processes can arise from transient amplification of individual-based knowledge.

  6. Efficient Egress of Escaping Ants Stressed with Temperature

    PubMed Central

    Boari, Santiago; Josens, Roxana; Parisi, Daniel R.

    2013-01-01

    In the present work we investigate the egress times of a group of Argentine ants (Linepithema humile) stressed with different heating speeds. We found that the higher the temperature ramp is, the faster ants evacuate showing, in this sense, a group-efficient evacuation strategy. It is important to note that even when the life of ants was in danger, jamming and clogging was not observed near the exit, in accordance with other experiments reported in the literature using citronella as aversive stimuli. Because of this clear difference between ants and humans, we recommend the use of some other animal models for studying competitive egress dynamics as a more accurate approach to understanding competitive egress in human systems. PMID:24312264

  7. All-Optical Implementation of the Ant Colony Optimization Algorithm

    PubMed Central

    Hu, Wenchao; Wu, Kan; Shum, Perry Ping; Zheludev, Nikolay I.; Soci, Cesare

    2016-01-01

    We report all-optical implementation of the optimization algorithm for the famous “ant colony” problem. Ant colonies progressively optimize pathway to food discovered by one of the ants through identifying the discovered route with volatile chemicals (pheromones) secreted on the way back from the food deposit. Mathematically this is an important example of graph optimization problem with dynamically changing parameters. Using an optical network with nonlinear waveguides to represent the graph and a feedback loop, we experimentally show that photons traveling through the network behave like ants that dynamically modify the environment to find the shortest pathway to any chosen point in the graph. This proof-of-principle demonstration illustrates how transient nonlinearity in the optical system can be exploited to tackle complex optimization problems directly, on the hardware level, which may be used for self-routing of optical signals in transparent communication networks and energy flow in photonic systems. PMID:27222098

  8. Florida alternative NTCIP testing software (ANTS) for actuated signal controllers.

    DOT National Transportation Integrated Search

    2009-01-01

    The scope of this research project did include the development of a software tool to test devices for NTCIP compliance. Development of the Florida Alternative NTCIP Testing Software (ANTS) was developed by the research team due to limitations found w...

  9. Ant groups optimally amplify the effect of transiently informed individuals

    PubMed Central

    Gelblum, Aviram; Pinkoviezky, Itai; Fonio, Ehud; Ghosh, Abhijit; Gov, Nir; Feinerman, Ofer

    2015-01-01

    To cooperatively transport a large load, it is important that carriers conform in their efforts and align their forces. A downside of behavioural conformism is that it may decrease the group's responsiveness to external information. Combining experiment and theory, we show how ants optimize collective transport. On the single-ant scale, optimization stems from decision rules that balance individuality and compliance. Macroscopically, these rules poise the system at the transition between random walk and ballistic motion where the collective response to the steering of a single informed ant is maximized. We relate this peak in response to the divergence of susceptibility at a phase transition. Our theoretical models predict that the ant-load system can be transitioned through the critical point of this mesoscopic system by varying its size; we present experiments supporting these predictions. Our findings show that efficient group-level processes can arise from transient amplification of individual-based knowledge. PMID:26218613

  10. Fluid intake rates in ants correlate with their feeding habits.

    PubMed

    Paul, J; Roces, F

    2003-04-01

    This study investigates the techniques of nectar feeding in 11 different ant species, and quantitatively compares fluid intake rates over a wide range of nectar concentrations in four species that largely differ in their feeding habits. Ants were observed to employ two different techniques for liquid food intake, in which the glossa works either as a passive duct-like structure (sucking), or as an up- and downwards moving shovel (licking). The technique employed for collecting fluids at ad libitum food sources was observed to be species-specific and to correlate with the presence or absence of a well-developed crop in the species under scrutiny. Workers of ponerine ants licked fluid food during foraging and transported it as a droplet between their mandibles, whereas workers of species belonging to phylogenetically more advanced subfamilies, with a crop capable of storing liquids, sucked the fluid food, such as formicine ants of the genus Camponotus. In order to evaluate the performance of fluid collection during foraging, intake rates for sucrose solutions of different concentrations were measured in four ant species that differ in their foraging ecology. Scaling functions between fluid intake rates and ant size were first established for the polymorphic species, so as to compare ants of different size across species. Results showed that fluid intake rate depended, as expected and previously reported in the literature, on sugar concentration and the associated fluid viscosity. It also depended on both the species-specific feeding technique and the extent of specialization on foraging on liquid food. For similarly-sized ants, workers of two nectar-feeding ant species, Camponotus rufipes (Formicinae) and Pachycondyla villosa (Ponerinae), collected fluids with the highest intake rates, while workers of the leaf-cutting ant Atta sexdens (Myrmicinae) and a predatory ant from the Rhytidoponera impressa-complex (Ponerinae) did so with the lowest rate. Calculating the

  11. Climatic warming destabilizes forest ant communities

    PubMed Central

    Diamond, Sarah E.; Nichols, Lauren M.; Pelini, Shannon L.; Penick, Clint A.; Barber, Grace W.; Cahan, Sara Helms; Dunn, Robert R.; Ellison, Aaron M.; Sanders, Nathan J.; Gotelli, Nicholas J.

    2016-01-01

    How will ecological communities change in response to climate warming? Direct effects of temperature and indirect cascading effects of species interactions are already altering the structure of local communities, but the dynamics of community change are still poorly understood. We explore the cumulative effects of warming on the dynamics and turnover of forest ant communities that were warmed as part of a 5-year climate manipulation experiment at two sites in eastern North America. At the community level, warming consistently increased occupancy of nests and decreased extinction and nest abandonment. This consistency was largely driven by strong responses of a subset of thermophilic species at each site. As colonies of thermophilic species persisted in nests for longer periods of time under warmer temperatures, turnover was diminished, and species interactions were likely altered. We found that dynamical (Lyapunov) community stability decreased with warming both within and between sites. These results refute null expectations of simple temperature-driven increases in the activity and movement of thermophilic ectotherms. The reduction in stability under warming contrasts with the findings of previous studies that suggest resilience of species interactions to experimental and natural warming. In the face of warmer, no-analog climates, communities of the future may become increasingly fragile and unstable. PMID:27819044

  12. Climatic warming destabilizes forest ant communities.

    PubMed

    Diamond, Sarah E; Nichols, Lauren M; Pelini, Shannon L; Penick, Clint A; Barber, Grace W; Cahan, Sara Helms; Dunn, Robert R; Ellison, Aaron M; Sanders, Nathan J; Gotelli, Nicholas J

    2016-10-01

    How will ecological communities change in response to climate warming? Direct effects of temperature and indirect cascading effects of species interactions are already altering the structure of local communities, but the dynamics of community change are still poorly understood. We explore the cumulative effects of warming on the dynamics and turnover of forest ant communities that were warmed as part of a 5-year climate manipulation experiment at two sites in eastern North America. At the community level, warming consistently increased occupancy of nests and decreased extinction and nest abandonment. This consistency was largely driven by strong responses of a subset of thermophilic species at each site. As colonies of thermophilic species persisted in nests for longer periods of time under warmer temperatures, turnover was diminished, and species interactions were likely altered. We found that dynamical (Lyapunov) community stability decreased with warming both within and between sites. These results refute null expectations of simple temperature-driven increases in the activity and movement of thermophilic ectotherms. The reduction in stability under warming contrasts with the findings of previous studies that suggest resilience of species interactions to experimental and natural warming. In the face of warmer, no-analog climates, communities of the future may become increasingly fragile and unstable.

  13. Deleterious Wolbachia in the ant Formica truncorum.

    PubMed

    Wenseleers, T; Sundström, L; Billen, J

    2002-03-22

    Wolbachia is a maternally inherited bacterium that may manipulate the reproduction of its arthropod hosts. In insects, it is known to lead to inviable matings, cause asexual reproduction or kill male offspring, all to its own benefit, but to the detriment of its host. In social Hymenoptera, Wolbachia occurs widely, but little is known about its fitness effects. We report on a Wolbachia infection in the wood ant Formica truncorum, and evaluate whether it influences reproductive patterns. All 33 colonies of the study population were infected, suggesting that Wolbachia infection is at, or close to, fixation. Interestingly, in colonies with fewer infected workers, significantly more sexuals are produced, indicating that Wolbachia has deleterious effects in this species. In addition, adult workers are shown to have significantly lower infection rates (45%) than worker pupae (87%) or virgin queens (94%), suggesting that workers lose their infection over life. Clearance of Wolbachia infection has, to our knowledge, never been shown in any other natural system, but we argue that it may, in this case, represent an adaptive strategy to reduce colony load. The cause of fixation requires further study, but our data strongly suggest that Wolbachia has no influence on the sex ratio in this species.

  14. Nasa's Ant-Inspired Swarmie Robots

    NASA Technical Reports Server (NTRS)

    Leucht, Kurt W.

    2016-01-01

    As humans push further beyond the grasp of earth, robotic missions in advance of human missions will play an increasingly important role. These robotic systems will find and retrieve valuable resources as part of an in-situ resource utilization (ISRU) strategy. They will need to be highly autonomous while maintaining high task performance levels. NASA Kennedy Space Center has teamed up with the Biological Computation Lab at the University of New Mexico to create a swarm of small, low-cost, autonomous robots to be used as a ground-based research platform for ISRU missions. The behavior of the robot swarm mimics the central-place foraging strategy of ants to find and collect resources in a previously unmapped environment and return those resources to a central site. This talk will guide the audience through the Swarmie robot project from its conception by students in a New Mexico research lab to its robot trials in an outdoor parking lot at NASA. The software technologies and techniques used on the project will be discussed, as well as various challenges and solutions that were encountered by the development team along the way.

  15. Ultraviolet radiation as an ant repellent

    SciTech Connect

    Thorvilson, H.G.; Russell, S.A.; Green, B.

    1996-12-31

    In an effort to repel red imported fire ants (RIFA) from electrical devices, such as transformers, ultraviolet (UV) light was tested. Initial tests determined if RIFA`s tolerate a UV-irradiated environment when given a choice between UV-irradiated and non-irradiated. All replications in this test indicated that RIFA`s are intolerant of UV-irradiation and sought to escape it. RIFA`s moved to shaded environments and transported their brood out its well. A second test sought to determine if long-term UV-irradiation of the entire colonies cause increased RIFA mortality. Queenright colonies were exposed to UV irradiation of 254nm constantly for 115 days and colonies hadmore » a higher mortality rate than did a control colony. RIFA`s attempted to escape UV light and had increased rate when exposed to UV (254nm), but a practical application of this technique may be detrimental to insulation on electrical wiring.« less

  16. Dentigerumycin: a bacterial mediator of an ant-fungus symbiosis

    PubMed Central

    Oh, Dong-Chan; Poulsen, Michael; Currie, Cameron R.; Clardy, Jon

    2009-01-01

    Fungus-growing ants engage in mutualistic associations with both the fungus they cultivate for food and actinobacteria (Pseudonocardia spp.) that produce selective antibiotics to defend that fungus from specialized fungal parasites. In the first system to be analyzed at the molecular level, the bacterium associated with the ant Apterostigma dentigerum produces dentigerumycin, a cyclic depsipeptide with highly modified amino acids, to selectively inhibit the parasitic fungus (Escovopsis sp.). PMID:19330011

  17. Trail pheromone disruption of Argentine ant trail formation and foraging.

    PubMed

    Suckling, David Maxwell; Peck, Robert W; Stringer, Lloyd D; Snook, Kirsten; Banko, Paul C

    2010-01-01

    Trail pheromone disruption of invasive ants is a novel tactic that builds on the development of pheromone-based pest management in other insects. Argentine ant trail pheromone, (Z)-9-hexadecenal, was formulated as a micro-encapsulated sprayable particle and applied against Argentine ant populations in 400 m2 field plots in Hawai'i Volcanoes National Park. A widely dispersed point source strategy for trail pheromone disruption was used. Traffic rates of ants in bioassays of treated filter paper, protected from rainfall and sunlight, indicated the presence of behaviorally significant quantities of pheromone being released from the formulation for up to 59 days. The proportion of plots, under trade wind conditions (2–3 m s−1), with visible trails was reduced for up to 14 days following treatment, and the number of foraging ants at randomly placed tuna-bait cards was similarly reduced. The success of these trail pheromone disruption trials in a natural ecosystem highlights the potential of this method for control of invasive ant species in this and other environments.

  18. Aversive learning of odor-heat associations in ants.

    PubMed

    Desmedt, Lucie; Baracchi, David; Devaud, Jean-Marc; Giurfa, Martin; d'Ettorre, Patrizia

    2017-12-15

    Ants have recently emerged as useful models for the study of olfactory learning. In this framework, the development of a protocol for the appetitive conditioning of the maxilla-labium extension response (MaLER) provided the possibility of studying Pavlovian odor-food learning in a controlled environment. Here we extend these studies by introducing the first Pavlovian aversive learning protocol for harnessed ants in the laboratory. We worked with carpenter ants Camponotus aethiops and first determined the capacity of different temperatures applied to the body surface to elicit the typical aversive mandible opening response (MOR). We determined that 75°C is the optimal temperature to induce MOR and chose the hind legs as the stimulated body region because of their high sensitivity. We then studied the ability of ants to learn and remember odor-heat associations using 75°C as the unconditioned stimulus. We studied learning and short-term retention after absolute (one odor paired with heat) and differential conditioning (a punished odor versus an unpunished odor). Our results show that ants successfully learn the odor-heat association under a differential-conditioning regime and thus exhibit a conditioned MOR to the punished odor. Yet, their performance under an absolute-conditioning regime is poor. These results demonstrate that ants are capable of aversive learning and confirm previous findings about the different attentional resources solicited by differential and absolute conditioning in general. © 2017. Published by The Company of Biologists Ltd.

  19. Water stress strengthens mutualism among ants, trees, and scale insects.

    PubMed

    Pringle, Elizabeth G; Akçay, Erol; Raab, Ted K; Dirzo, Rodolfo; Gordon, Deborah M

    2013-11-01

    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant-plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant-plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism.

  20. Action of Ants on Vertebrate Carcasses and Blow Flies (Calliphoridae).

    PubMed

    Paula, Michele C; Morishita, Gustavo M; Cavarson, Carolina H; Gonçalves, Cristiano R; Tavares, Paulo R A; Mendonça, Angélica; Súarez, Yzel R; Antonialli-Junior, William F

    2016-11-01

    Forensic entomology is a science that uses insect fauna as a tool to assist in criminal investigations and civil proceedings. Although the most researched insects are the Diptera and Coleoptera, ants may be present in all stages of decomposition. The aim of this study was to evaluate the role of ants and their action on blow flies during the decomposition process. Experiments were performed in which four pig carcasses were exposed in the cold and dry season (November/2012 and March/2013) and four in the hot and wet season (May/2013 and August/2013). Flies were the first insects to detect and interact with the carcasses, and six species of the Calliphoridae family were identified. Ants (Hymenoptera: Formicidae) were the second group, with six subfamilies identified. Myrmycinae represented 42% of the species, followed by Formicinae (28%), Ectatominae and Ponerinae (both 10%), and Ecitoninae and Dolichoderinae (both 5%). The ants acted on the carcasses as predators of visiting species, omnivores, and necrophagous, in all cases significantly affecting the decomposition time, slowing it down when the ants preyed on adult and immature insects consuming the carcass, or accelerating it by consuming the carcass and creating holes that could serve as gateways for the action of other organisms. The ants also generated artifacts that could lead to forensic misinterpretation. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  1. An invasive slug exploits an ant-seed dispersal mutualism.

    PubMed

    Meadley Dunphy, Shannon A; Prior, Kirsten M; Frederickson, Megan E

    2016-05-01

    Plant-animal mutualisms, such as seed dispersal, are often vulnerable to disruption by invasive species. Here, we show for the first time how a non-ant invasive species negatively affects seed dispersal by ants. We examined the effects of several animal species that co-occur in a temperate deciduous forest-including native and invasive seed-dispersing ants (Aphaenogaster rudis and Myrmica rubra, respectively), an invasive slug (Arion subfuscus), and native rodents-on a native myrmecochorous plant, Asarum canadense. We experimentally manipulated ant, slug, and rodent access to seed depots and measured seed removal. We also video-recorded depots to determine which other taxa interact with seeds. We found that A. rudis was the main disperser of seeds and that A. subfuscus consumed elaiosomes without dispersing seeds. Rodent visitation was rare, and rodent exclusion had no significant effect on seed or elaiosome removal. We then used data obtained from laboratory and field mesocosm experiments to determine how elaiosome robbing by A. subfuscus affects seed dispersal by A. rudis and M. rubra. We found that elaiosome robbing by slugs reduced seed dispersal by ants, especially in mesocosms with A. rudis, which picks up seeds more slowly than M. rubra. Taken together, our results show that elaiosome robbing by an invasive slug reduces seed dispersal by ants, suggesting that invasive slugs can have profound negative effects on seed dispersal mutualisms.

  2. [Ants as carriers of microorganisms in hospital environments].

    PubMed

    Pereira, Rogério Dos Santos; Ueno, Mariko

    2008-01-01

    Concern exists regarding the real possibility of public health threats caused by pathogenic agents that are carried by urban ants. The present study had the objective of isolating and identifying the microorganisms that are associated with ants in hospital environments. One hundred and twenty-five ants of the same species were collected from different units of a university hospital. Each ant was collected using a swab soaked with physiological solution and was transferred to a tube containing brain heart infusion broth and incubated at 35 degrees C for 24 hours. From each tube, with growth, inoculations were made into specific culturing media, to isolate any microorganisms. The ants presented a high capacity for carrying microorganism groups: spore-producing Gram-positive bacilli 63.5%, Gram-negative bacilli 6.3%, Gram-positive cocci 23.1%, filamentous fungi 6.7% and yeast 0.5%. Thus, it can be inferred that ants may be one of the agents responsible for disseminating microorganisms in hospital environments.

  3. The adaptive significance of phasic colony cycles in army ants.

    PubMed

    Garnier, Simon; Kronauer, Daniel J C

    2017-09-07

    Army ants are top arthropod predators in tropical forests around the world. The colonies of many army ant species undergo stereotypical behavioral and reproductive cycles, alternating between brood care and reproductive phases. In the brood care phase, colonies contain a cohort of larvae that are synchronized in their development and have to be fed. In the reproductive phase larvae are absent and oviposition takes place. Despite these colony cycles being a striking feature of army ant biology, their adaptive significance is unclear. Here we use a modeling approach to show that cyclic reproduction is favored under conditions where per capita foraging costs decrease with the number of larvae in a colony ("High Cost of Entry" scenario), while continuous reproduction is favored under conditions where per capita foraging costs increase with the number of larvae ("Resource Exhaustion" scenario). We argue that the former scenario specifically applies to army ants, because large raiding parties are required to overpower prey colonies. However, once raiding is successful it provides abundant food for a large cohort of larvae. The latter scenario, on the other hand, will apply to non-army ants, because in those species local resource depletion will force workers to forage over larger distances to feed large larval cohorts. Our model provides a quantitative framework for understanding the adaptive value of phasic colony cycles in ants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. No sex in fungus-farming ants or their crops.

    PubMed

    Himler, Anna G; Caldera, Eric J; Baer, Boris C; Fernández-Marín, Hermógenes; Mueller, Ulrich G

    2009-07-22

    Asexual reproduction imposes evolutionary handicaps on asexual species, rendering them prone to extinction, because asexual reproduction generates novel genotypes and purges deleterious mutations at lower rates than sexual reproduction. Here, we report the first case of complete asexuality in ants, the fungus-growing ant Mycocepurus smithii, where queens reproduce asexually but workers are sterile, which is doubly enigmatic because the clonal colonies of M. smithii also depend on clonal fungi for food. Degenerate female mating anatomy, extensive field and laboratory surveys, and DNA fingerprinting implicate complete asexuality in this widespread ant species. Maternally inherited bacteria (e.g. Wolbachia, Cardinium) and the fungal cultivars can be ruled out as agents inducing asexuality. M. smithii societies of clonal females provide a unique system to test theories of parent-offspring conflict and reproductive policing in social insects. Asexuality of both ant farmer and fungal crop challenges traditional views proposing that sexual farmer ants outpace coevolving sexual crop pathogens, and thus compensate for vulnerabilities of their asexual crops. Either the double asexuality of both farmer and crop may permit the host to fully exploit advantages of asexuality for unknown reasons or frequent switching between crops (symbiont reassociation) generates novel ant-fungus combinations, which may compensate for any evolutionary handicaps of asexuality in M. smithii.

  5. Reaction of mutualistic and granivorous ants to ulex elaiosome chemicals.

    PubMed

    Gammans, Nicola; Bullock, James M; Gibbons, Hannah; Schönrogge, Karsten

    2006-09-01

    It has been proposed that chemicals on plant elaiosomes aid seed detection by seed-dispersing ants. We hypothesized that the chemical interaction between ants and elaiosomes is more intimate than a generic attraction, and that elaiosome chemicals will attract mutualistic but not granivorous ant species. We investigated this by using two gorse species, Ulex minor and U. europaeus, and two associated ant species from European heathlands, the mutualist Myrmica ruginodis and the granivore Tetramorium caespitum. Behavioral studies were conducted with laboratory nests and foraging arenas. Both ants will take Ulex seeds, but while M. ruginodis showed increased antennation toward ether extracts of elaiosome surface chemicals compared with controls, T. caespitum showed no response. Elaiosome extracts were separated into seven lipid fractions. M. ruginodis showed increased antennation only toward the diglyceride fractions of both Ulex species, whereas T. caespitum showed no consistent reaction. This indicates that M. ruginodis can detect the elaiosome by responding to its surface chemicals, but T. caespitum is unresponsive to these chemicals. Responses to surface chemicals could increase the rate of seed detection in the field, and so these results suggest that Ulex elaiosomes produce chemicals that facilitate attraction of mutualistic rather than granivorous ant species. This could reduce seed predation and increase Ulex fitness.

  6. Bait distribution among multiple colonies of Pharaoh ants (hymenoptera: Formicidae).

    PubMed

    Oi, D H; Vail, K M; Williams, D F

    2000-08-01

    Pharaoh ant, Monomorium pharaonis (L.), infestations often consist of several colonies located at different nest sites. To achieve control, it is desirable to suppress or eliminate the populations of a majority of these colonies. We compared the trophallactic distribution and efficacy of two ant baits, with different modes of action, among groups of four colonies of Pharaoh ants. Baits contained either the metabolic-inhibiting active ingredient hydramethylnon or the insect growth regulator (IGR) pyriproxyfen. Within 3 wk, the hydramethylnon bait reduced worker and brood populations by at least 80%, and queen reductions ranged between 73 and 100%, when nests were in proximity (within 132 cm) to the bait source. However, these nest sites were reoccupied by ants from other colonies located further from the bait source. The pyriproxyfen bait was distributed more thoroughly to all nest locations with worker populations gradually declining by 73% at all nest sites after 8 wk. Average queen reductions ranged from 31 to 49% for all nest sites throughout the study. Even though some queens survived, brood reductions were rapid in the pyriproxyfen treatment, with reductions of 95% at all locations by week 3. Unlike the metabolic inhibitor, the IGR did not kill adult worker ants quickly, thus, more surviving worker ants were available to distribute the bait to all colonies located at different nest sites. Thus, from a single bait source, the slow-acting bait toxicant provided gradual, but long-term control, whereas the fast-acting bait toxicant provided rapid, localized control for a shorter duration.

  7. Colony Fusion in a Parthenogenetic Ant, Pristomyrmex punctatus

    PubMed Central

    Satow, Show; Satoh, Toshiyuki; Hirota, Tadao

    2013-01-01

    In the ant Pristomyrmex punctatus Smith (Hymenoptera: Formicidae), all young workers lay a small number of eggs parthenogenetically. Some colonies consist of monoclonal individuals that provide high inclusive fitness, according to the kin selection theory. However, in some populations, a majority of the colonies contain multiple lineages. Intracolonial genetic variation of parthenogenetic ants cannot be explained by the multiple mating of single founderesses or by the foundation of a colony by multiple foundresses, which are the usual causes of genetically diverse colonies in social insects. Here, we hypothesized that the fusion of established colonies might facilitate the formation of multiclonal colonies. Colony fusion decreases indirect benefits because of the reduction in intracolonial relatedness. However, when suitable nesting places for overwintering are scarce, colony fusion provides a strategy for the survival of colonies. Here, ants derived from different colonies were allowed to encounter one another in a container with just one nesting place. Initially, high aggression was observed; however, after several days, no aggression was observed and the ants shared the nest. When the fused colonies were allowed to transfer to two alternative nests, ants from different colonies occupied the same nest. This study highlights the importance of limiting the number of nesting places in order to understand the genetic diversity of parthenogenetic ant colonies. PMID:23895053

  8. Looking and homing: how displaced ants decide where to go

    PubMed Central

    Zeil, Jochen; Narendra, Ajay; Stürzl, Wolfgang

    2014-01-01

    We caught solitary foragers of the Australian Jack Jumper ant, Myrmecia croslandi, and released them in three compass directions at distances of 10 and 15 m from the nest at locations they have never been before. We recorded the head orientation and the movements of ants within a radius of 20 cm from the release point and, in some cases, tracked their subsequent paths with a differential GPS. We find that upon surfacing from their transport vials onto a release platform, most ants move into the home direction after looking around briefly. The ants use a systematic scanning procedure, consisting of saccadic head and body rotations that sweep gaze across the scene with an average angular velocity of 90° s−1 and intermittent changes in turning direction. By mapping the ants’ gaze directions onto the local panorama, we find that neither the ants’ gaze nor their decisions to change turning direction are clearly associated with salient or significant features in the scene. Instead, the ants look most frequently in the home direction and start walking fast when doing so. Displaced ants can thus identify home direction with little translation, but exclusively through rotational scanning. We discuss the navigational information content of the ants’ habitat and how the insects’ behaviour informs us about how they may acquire and retrieve that information. PMID:24395961

  9. Chaos–order transition in foraging behavior of ants

    PubMed Central

    Li, Lixiang; Peng, Haipeng; Kurths, Jürgen; Yang, Yixian; Schellnhuber, Hans Joachim

    2014-01-01

    The study of the foraging behavior of group animals (especially ants) is of practical ecological importance, but it also contributes to the development of widely applicable optimization problem-solving techniques. Biologists have discovered that single ants exhibit low-dimensional deterministic-chaotic activities. However, the influences of the nest, ants’ physical abilities, and ants’ knowledge (or experience) on foraging behavior have received relatively little attention in studies of the collective behavior of ants. This paper provides new insights into basic mechanisms of effective foraging for social insects or group animals that have a home. We propose that the whole foraging process of ants is controlled by three successive strategies: hunting, homing, and path building. A mathematical model is developed to study this complex scheme. We show that the transition from chaotic to periodic regimes observed in our model results from an optimization scheme for group animals with a home. According to our investigation, the behavior of such insects is not represented by random but rather deterministic walks (as generated by deterministic dynamical systems, e.g., by maps) in a random environment: the animals use their intelligence and experience to guide them. The more knowledge an ant has, the higher its foraging efficiency is. When young insects join the collective to forage with old and middle-aged ants, it benefits the whole colony in the long run. The resulting strategy can even be optimal. PMID:24912159

  10. Trail Pheromone Disruption of Argentine Ant Trail Formation and Foraging

    USGS Publications Warehouse

    Suckling, D.M.; Peck, R.W.; Stringer, L.D.; Snook, K.; Banko, P.C.

    2010-01-01

    Trail pheromone disruption of invasive ants is a novel tactic that builds on the development of pheromone-based pest management in other insects. Argentine ant trail pheromone, (Z)-9-hexadecenal, was formulated as a micro-encapsulated sprayable particle and applied against Argentine ant populations in 400 m2 field plots in Hawai'i Volcanoes National Park. A widely dispersed point source strategy for trail pheromone disruption was used. Traffic rates of ants in bioassays of treated filter paper, protected from rainfall and sunlight, indicated the presence of behaviorally significant quantities of pheromone being released from the formulation for up to 59 days. The proportion of plots, under trade wind conditions (2-3 m s-1), with visible trails was reduced for up to 14 days following treatment, and the number of foraging ants at randomly placed tuna-bait cards was similarly reduced. The success of these trail pheromone disruption trials in a natural ecosystem highlights the potential of this method for control of invasive ant species in this and other environments. ?? Springer Science+Business Media, LLC 2010.

  11. Ant predation on herbivores through a multitrophic lens: how effects of ants on plant herbivore defense and natural enemies vary along temperature gradients.

    PubMed

    Rodríguez-Castañeda, G; Brehm, G; Fiedler, K; Dyer, L A

    2016-04-01

    Ants are keystone predators in terrestrial trophic cascades. Addressing ants' roles in multitrophic interactions across regional gradients is important for understanding mechanisms behind range limits of species. We present four hypotheses of trophic dynamics occurring when ants are rare: first, there is a shift in predator communities; second, plants decrease investments in ant attraction and increase production of secondary metabolites; third, lower herbivory at high elevations allows plants to tolerate herbivory; and fourth, distribution of ant-plants can be limited based on ant abundance. Conducting experiments on multitrophic effects of ants across elevational gradients, and incorporating these results to ecological niche modeling (ENM) will improve our knowledge of the impacts of global change on ants, trophic interactions, and biodiversity. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Using ant-behavior-based simulation model AntWeb to improve website organization

    NASA Astrophysics Data System (ADS)

    Li, Weigang; Pinheiro Dib, Marcos V.; Teles, Wesley M.; Morais de Andrade, Vlaudemir; Alves de Melo, Alba C. M.; Cariolano, Judas T.

    2002-03-01

    Some web usage mining algorithms showed the potential application to find the difference among the organizations expected by visitors to the website. However, there are still no efficient method and criterion for a web administrator to measure the performance of the modification. In this paper, we developed an AntWeb, a model inspired by ants' behavior to simulate the sequence of visiting the website, in order to measure the efficient of the web structure. We implemented a web usage mining algorithm using backtrack to the intranet website of the Politec Informatic Ltd., Brazil. We defined throughput (the number of visitors to reach their target pages per time unit relates to the total number of visitors) as an index to measure the website's performance. We also used the link in a web page to represent the effect of visitors' pheromone trails. For every modification in the website organization, for example, putting a link from the expected location to the target object, the simulation reported the value of throughput as a quick answer about this modification. The experiment showed the stability of our simulation model, and a positive modification to the intranet website of the Politec.

  13. Alkaloid venom weaponry of three Megalomyrmex thief ants and the behavioral response of Cyphomyrmex costatus host ants.

    PubMed

    Adams, Rachelle M M; Jones, Tappey H; Longino, John T; Weatherford, Robert G; Mueller, Ulrich G

    2015-04-01

    Social parasites exploit other societies by invading and stealing resources. Some enter protected nests using offensive chemical weaponry made from alkaloid-based venom. We characterized the venoms of three Megalomyrmex thief ant species (M. mondabora, M. mondaboroides, and M. silvestrii) that parasitize the fungus-growing ants, and developed an ethogram to describe host ant reactions to raiding M. mondaboroides and M. silvestrii parasites. We compared piperidine, pyrrolidine, and pyrolizidine venom alkaloid structures with synthetic samples from previous studies, and describe the novel stereochemistry of trans 2-hexyl-5-[8-oxononyl]-pyrrolidine (3) from M. mondabora. We showed that workers of Cyphomyrmex costatus, the host of M. mondaboroides and M. silvestrii, react to a sting by Megalomyrmex parasites mainly with submissive behavior, playing dead or retreating. Host submission also followed brief antennal contact. The behavior of C. costatus ants observed in this study was similar to that of Cyphomyrmex cornutus, host of M. mondabora, suggesting that the alkaloidal venoms with pyrrolidines from M. mondabora, piperidines from M. mondaboroides, and pyrolizidines from M. silvestrii may function similarly as appeasement and repellent allomones against host ants, despite their different chemical structure. With the use of these chemical weapons, the Megalomyrmex thief ants are met with little host resistance and easily exploit host colony resources.

  14. Foraging ants trade off further for faster: use of natural bridges and trunk trail permanency in carpenter ants

    NASA Astrophysics Data System (ADS)

    Loreto, Raquel G.; Hart, Adam G.; Pereira, Thairine M.; Freitas, Mayara L. R.; Hughes, David P.; Elliot, Simon L.

    2013-10-01

    Trail-making ants lay pheromones on the substrate to define paths between foraging areas and the nest. Combined with the chemistry of these pheromone trails and the physics of evaporation, trail-laying and trail-following behaviours provide ant colonies with the quickest routes to food. In relatively uniform environments, such as that provided in many laboratory studies of trail-making ants, the quickest route is also often the shortest route. Here, we show that carpenter ants ( Camponotus rufipes), in natural conditions, are able to make use of apparent obstacles in their environment to assist in finding the fastest routes to food. These ants make extensive use of fallen branches, twigs and lianas as bridges to build their trails. These bridges make trails significantly longer than their straight line equivalents across the forest floor, but we estimate that ants spend less than half the time to reach the same point, due to increased carriage speed across the bridges. We also found that these trails, mainly composed of bridges, are maintained for months, so they can be characterized as trunk trails. We suggest that pheromone-based foraging trail networks in field conditions are likely to be structured by a range of potentially complex factors but that even then, speed remains the most important consideration.

  15. A Systematic Review of Global Drivers of Ant Elevational Diversity

    PubMed Central

    Szewczyk, Tim; McCain, Christy M.

    2016-01-01

    Ant diversity shows a variety of patterns across elevational gradients, though the patterns and drivers have not been evaluated comprehensively. In this systematic review and reanalysis, we use published data on ant elevational diversity to detail the observed patterns and to test the predictions and interactions of four major diversity hypotheses: thermal energy, the mid-domain effect, area, and the elevational climate model. Of sixty-seven published datasets from the literature, only those with standardized, comprehensive sampling were used. Datasets included both local and regional ant diversity and spanned 80° in latitude across six biogeographical provinces. We used a combination of simulations, linear regressions, and non-parametric statistics to test multiple quantitative predictions of each hypothesis. We used an environmentally and geometrically constrained model as well as multiple regression to test their interactions. Ant diversity showed three distinct patterns across elevations: most common were hump-shaped mid-elevation peaks in diversity, followed by low-elevation plateaus and monotonic decreases in the number of ant species. The elevational climate model, which proposes that temperature and precipitation jointly drive diversity, and area were partially supported as independent drivers. Thermal energy and the mid-domain effect were not supported as primary drivers of ant diversity globally. The interaction models supported the influence of multiple drivers, though not a consistent set. In contrast to many vertebrate taxa, global ant elevational diversity patterns appear more complex, with the best environmental model contingent on precipitation levels. Differences in ecology and natural history among taxa may be crucial to the processes influencing broad-scale diversity patterns. PMID:27175999

  16. Effects of isolation on ant assemblages depend on microhabitat

    USGS Publications Warehouse

    Chen, Xuan; Adams, Benjamin; Layne, Michael; Swarzenski, Christopher M.; Norris, David O.; Hooper-Bui, Linda

    2017-01-01

    How isolation affects biological communities is a fundamental question in ecology and conservation biology. Local diversity (α) and regional diversity (γ) are consistently lower in insular areas. The pattern of species turnover (β diversity) and the influence of isolation on competitive interactions are less predictable. Differences in communities across microhabitats within an isolated patch could contribute to the variability in patterns related to isolation. Trees form characteristically dense and sparse patches (low vs. high isolation) in floating marshes in coastal Louisiana, and canopy and root areas around these trees could support distinct ant communities. Consequently, trees in floating marshes provide an ideal environment to study the effects of isolation on community assemblages in different microhabitats. We sampled ant communities in 120 trees during the summer of 2016. We found ant α diversity was not different between the canopy and roots, and the magnitude and directional effects of isolation on ants were inconsistent between the canopy and root areas. In the roots of sparse sites, ant diversity (α, β, and γ) was lower, species composition was changed, and the signature of interspecific competition was more prominent compared to dense sites. In the canopy, however, significant differences between dense and sparse sites were only detected in α and γ diversity, and ant species co‐occurrence was not significantly different from a random distribution. The inconsistent responses of ants in canopy and root areas to isolation may be due to the differences of species pool size, environmental harshness, and species interactions between strata. In addition, these findings indicate that communities in distinct microenvironments can respond differentially to habitat isolation. We suggest incorporating organisms from different microhabitats into future research to better understand the influence of isolation on the assembly of biological communities.

  17. Ant Foraging As an Indicator of Tropical Dry Forest Restoration.

    PubMed

    Hernández-Flores, J; Osorio-Beristain, M; Martínez-Garza, C

    2016-08-01

    Variation in foraging behavior may indicate differences in food availability and allow assessment of restoration actions. Ants are prominent bioindicators used in assessing ecological responses to disturbance. However, behavioral data have been poorly incorporated as an index. The foraging performance of red harvester ants was quantified in order to evaluate the success of a restoration ecology experiment in the tropical dry forest of Sierra de Huautla, Morelos, in central Mexico. Foraging performance by granivorous, Pogonomyrmex barbatus, ants was diminished after 6 and 8 years of cattle grazing and wood harvest were excluded as part of a restoration experiment in a highly degraded biome. Despite investing more time in foraging, ant colonies in exclusion plots showed lower foraging success and acquired less seed biomass than colonies in control plots. In line with the predictions of optimal foraging theory, in restored plots where ant foraging performance was poor, ants harvested a higher diversity of seeds. Reduced foraging success and increased harvest of non-preferred foods in exclusion plots were likely due to the growth of herbaceous vegetation, which impedes travel by foragers. Moreover, by 8 years of exclusion, 37% of nests in exclusion plots had disappeared compared to 0% of nests in control plots. Ants' foraging success and behavior were sensitive to changes in habitat quality due to the plant successional process triggered by a restoration intervention. This study spotlights on the utility of animal foraging behavior in the evaluation of habitat restoration programs. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. USING ANT COMMUNITIES FOR RAPID ASSESSMENT OF TERRESTRIAL ECOSYSTEM HEALTH

    SciTech Connect

    Wike, L; Doug Martin, D; Michael Paller, M

    2007-01-12

    Ecosystem health with its near infinite number of variables is difficult to measure, and there are many opinions as to which variables are most important, most easily measured, and most robust, Bioassessment avoids the controversy of choosing which physical and chemical parameters to measure because it uses responses of a community of organisms that integrate all aspects of the system in question. A variety of bioassessment methods have been successfully applied to aquatic ecosystems using fish and macroinvertebrate communities. Terrestrial biotic index methods are less developed than those for aquatic systems and we are seeking to address this problem here.more » This study had as its objective to examine the baseline differences in ant communities at different seral stages from clear cut back to mature pine plantation as a precursor to developing a bioassessment protocol. Comparative sampling was conducted at four seral stages; clearcut, 5 year, 15 year and mature pine plantation stands. Soil and vegetation data were collected at each site. All ants collected were preserved in 70% ethyl alcohol and identified to genus. Analysis of the ant data indicates that ants respond strongly to the habitat changes that accompany ecological succession in managed pine forests and that individual genera as well as ant community structure can be used as an indicator of successional change. Ants exhibited relatively high diversity in both early and mature seral stages. High ant diversity in the mature seral stages was likely related to conditions on the forest floor which favored litter dwelling and cool climate specialists.« less

  19. Various chemical strategies to deceive ants in three Arhopala species (lepidoptera: Lycaenidae) exploiting Macaranga myrmecophytes.

    PubMed

    Inui, Yoko; Shimizu-Kaya, Usun; Okubo, Tadahiro; Yamsaki, Eri; Itioka, Takao

    2015-01-01

    Macaranga myrmecophytes (ant-plants) are generally well protected from herbivore attacks by their symbiotic ants (plant-ants). However, larvae of Arhopala (Lepidoptera: Lycaenidae) species survive and develop on specific Macaranga ant-plant species without being attacked by the plant-ants of their host species. We hypothesized that Arhopala larvae chemically mimic or camouflage themselves with the ants on their host plant so that the larvae are accepted by the plant-ant species of their host. Chemical analyses of cuticular hydrocarbons showed that chemical congruency varied among Arhopala species; A. dajagaka matched well the host plant-ants, A. amphimuta did not match, and unexpectedly, A. zylda lacked hydrocarbons. Behaviorally, the larvae and dummies coated with cuticular chemicals of A. dajagaka were well attended by the plant-ants, especially by those of the host. A. amphimuta was often attacked by all plant-ants except for the host plant-ants toward the larvae, and those of A. zylda were ignored by all plant-ants. Our results suggested that conspicuous variations exist in the chemical strategies used by the myrmecophilous butterflies that allow them to avoid ant attack and be accepted by the plant-ant colonies.

  20. Various Chemical Strategies to Deceive Ants in Three Arhopala Species (Lepidoptera: Lycaenidae) Exploiting Macaranga Myrmecophytes

    PubMed Central

    Inui, Yoko; Shimizu-kaya, Usun; Okubo, Tadahiro; Yamsaki, Eri; Itioka, Takao

    2015-01-01

    Macaranga myrmecophytes (ant-plants) are generally well protected from herbivore attacks by their symbiotic ants (plant-ants). However, larvae of Arhopala (Lepidoptera: Lycaenidae) species survive and develop on specific Macaranga ant-plant species without being attacked by the plant-ants of their host species. We hypothesized that Arhopala larvae chemically mimic or camouflage themselves with the ants on their host plant so that the larvae are accepted by the plant-ant species of their host. Chemical analyses of cuticular hydrocarbons showed that chemical congruency varied among Arhopala species; A. dajagaka matched well the host plant-ants, A. amphimuta did not match, and unexpectedly, A. zylda lacked hydrocarbons. Behaviorally, the larvae and dummies coated with cuticular chemicals of A. dajagaka were well attended by the plant-ants, especially by those of the host. A. amphimuta was often attacked by all plant-ants except for the host plant-ants toward the larvae, and those of A. zylda were ignored by all plant-ants. Our results suggested that conspicuous variations exist in the chemical strategies used by the myrmecophilous butterflies that allow them to avoid ant attack and be accepted by the plant-ant colonies. PMID:25853675

  1. Feasibility Study of Economics and Performance of Solar Photovoltaics at the Crazy Horse Landfill Site in Salinas, California. A Study Prepared in Partnership with the Environmental Protection Agency for the RE-Powering America's Land Initiative: Siting Renewable Energy on Potentially Contaminated Land and Mine Sites

    SciTech Connect

    Stoltenberg, B.; Konz, C.; Mosey, G.

    2013-03-01

    The U.S. Environmental Protection Agency (EPA), in accordance with the RE-Powering America's Land initiative, selected the Crazy Horse Landfill site in Salinas, California, for a feasibility study of renewable energy production. The National Renewable Energy Laboratory (NREL) was contacted to provide technical assistance for this project. The purpose of this report is to assess the site for a possible photovoltaic (PV) system installation and estimate the cost, performance, operation and maintenance requirements, and site impacts of different PV options. In addition, the report recommends financing options that could assist in the implementation of a PV system at the site.

  2. New records of ant species from Yunnan, China

    PubMed Central

    Liu, Cong; Guénard, Benoit; Garcia, Francisco Hita; Yamane, Seiki; Blanchard, Benjamin; Yang, Da-Rong; Economo, Evan

    2015-01-01

    Abstract As with many other regions of the world, significant collecting, curation, and taxonomic efforts will be needed to complete the inventory of China’s ant fauna. This is especially true for the highly diverse tropical regions in the south of the country, where moist tropical forests harbor high species richness typical of the Southeast Asian region. We inventoried ants in the Xingshuangbanna prefecture, Yunnan, in June 2013, using a variety of methods including Winkler extraction and hand collection to sample ant diversity. We identified 213 species/morphospecies of ants from 10 subfamilies and 61 genera. After identification of 148 valid species of the 213 total species collected, 40 species represent new records for Yunnan province and 17 species are newly recorded for China. This increases the total number of named ant species in Yunnan and China to 447 and 951 respectively. The most common species collected were Brachyponera luteipes and Vollenhovia emeryi. Only one confirmed exotic species Strumigenys membranifera, was collected, although several others were potentially introduced by humans. These results highlight the high biodiversity value of the region, but also underscore how much work remains to fully document the native myrmecofauna. PMID:25685004

  3. Ant-like task allocation and recruitment in cooperative robots

    NASA Astrophysics Data System (ADS)

    Krieger, Michael J. B.; Billeter, Jean-Bernard; Keller, Laurent

    2000-08-01

    One of the greatest challenges in robotics is to create machines that are able to interact with unpredictable environments in real time. A possible solution may be to use swarms of robots behaving in a self-organized manner, similar to workers in an ant colony. Efficient mechanisms of division of labour, in particular series-parallel operation and transfer of information among group members, are key components of the tremendous ecological success of ants. Here we show that the general principles regulating division of labour in ant colonies indeed allow the design of flexible, robust and effective robotic systems. Groups of robots using ant-inspired algorithms of decentralized control techniques foraged more efficiently and maintained higher levels of group energy than single robots. But the benefits of group living decreased in larger groups, most probably because of interference during foraging. Intriguingly, a similar relationship between group size and efficiency has been documented in social insects. Moreover, when food items were clustered, groups where robots could recruit other robots in an ant-like manner were more efficient than groups without information transfer, suggesting that group dynamics of swarms of robots may follow rules similar to those governing social insects.

  4. Visual Navigation during Colony Emigration by the Ant Temnothorax rugatulus

    PubMed Central

    Bowens, Sean R.; Glatt, Daniel P.; Pratt, Stephen C.

    2013-01-01

    Many ants rely on both visual cues and self-generated chemical signals for navigation, but their relative importance varies across species and context. We evaluated the roles of both modalities during colony emigration by Temnothorax rugatulus. Colonies were induced to move from an old nest in the center of an arena to a new nest at the arena edge. In the midst of the emigration the arena floor was rotated 60°around the old nest entrance, thus displacing any substrate-bound odor cues while leaving visual cues unchanged. This manipulation had no effect on orientation, suggesting little influence of substrate cues on navigation. When this rotation was accompanied by the blocking of most visual cues, the ants became highly disoriented, suggesting that they did not fall back on substrate cues even when deprived of visual information. Finally, when the substrate was left in place but the visual surround was rotated, the ants' subsequent headings were strongly rotated in the same direction, showing a clear role for visual navigation. Combined with earlier studies, these results suggest that chemical signals deposited by Temnothorax ants serve more for marking of familiar territory than for orientation. The ants instead navigate visually, showing the importance of this modality even for species with small eyes and coarse visual acuity. PMID:23671713

  5. Ants avoid superinfections by performing risk-adjusted sanitary care.

    PubMed

    Konrad, Matthias; Pull, Christopher D; Metzler, Sina; Seif, Katharina; Naderlinger, Elisabeth; Grasse, Anna V; Cremer, Sylvia

    2018-03-13

    Being cared for when sick is a benefit of sociality that can reduce disease and improve survival of group members. However, individuals providing care risk contracting infectious diseases themselves. If they contract a low pathogen dose, they may develop low-level infections that do not cause disease but still affect host immunity by either decreasing or increasing the host's vulnerability to subsequent infections. Caring for contagious individuals can thus significantly alter the future disease susceptibility of caregivers. Using ants and their fungal pathogens as a model system, we tested if the altered disease susceptibility of experienced caregivers, in turn, affects their expression of sanitary care behavior. We found that low-level infections contracted during sanitary care had protective or neutral effects on secondary exposure to the same (homologous) pathogen but consistently caused high mortality on superinfection with a different (heterologous) pathogen. In response to this risk, the ants selectively adjusted the expression of their sanitary care. Specifically, the ants performed less grooming and more antimicrobial disinfection when caring for nestmates contaminated with heterologous pathogens compared with homologous ones. By modulating the components of sanitary care in this way the ants acquired less infectious particles of the heterologous pathogens, resulting in reduced superinfection. The performance of risk-adjusted sanitary care reveals the remarkable capacity of ants to react to changes in their disease susceptibility, according to their own infection history and to flexibly adjust collective care to individual risk.

  6. Stigmergic construction and topochemical information shape ant nest architecture

    PubMed Central

    Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

    2016-01-01

    The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture. PMID:26787857

  7. New fossil ants in French Cretaceous amber (Hymenoptera: Formicidae)

    NASA Astrophysics Data System (ADS)

    Perrichot, Vincent; Nel, André; Néraudeau, Didier; Lacau, Sébastien; Guyot, Thierry

    2008-02-01

    Recent studies on the ant phylogeny are mainly based on the molecular analyses of extant subfamilies and do not include the extinct, only Cretaceous subfamily Sphecomyrminae. However, the latter is of major importance for ant relationships, as it is considered the most basal subfamily. Therefore, each new discovery of a Mesozoic ant is of high interest for improving our understanding of their early history and basal relationships. In this paper, a new sphecomyrmine ant, allied to the Burmese amber genus Haidomyrmex, is described from mid-Cretaceous amber of France as Haidomyrmodes mammuthus gen. and sp. n. The diagnosis of the tribe Haidomyrmecini is emended based on the new type material, which includes a gyne (alate female) and two incomplete workers. The genus Sphecomyrmodes, hitherto known by a single species from Burmese amber, is also reported and a new species described as S. occidentalis sp. n. after two workers remarkably preserved in a single piece of Early Cenomanian French amber. The new fossils provide additional information on early ant diversity and relationships and demonstrate that the monophyly of the Sphecomyrminae, as currently defined, is still weakly supported.

  8. Polarized light use in the nocturnal bull ant, Myrmecia midas.

    PubMed

    Freas, Cody A; Narendra, Ajay; Lemesle, Corentin; Cheng, Ken

    2017-08-01

    Solitary foraging ants have a navigational toolkit, which includes the use of both terrestrial and celestial visual cues, allowing individuals to successfully pilot between food sources and their nest. One such celestial cue is the polarization pattern in the overhead sky. Here, we explore the use of polarized light during outbound and inbound journeys and with different home vectors in the nocturnal bull ant, Myrmecia midas . We tested foragers on both portions of the foraging trip by rotating the overhead polarization pattern by ±45°. Both outbound and inbound foragers responded to the polarized light change, but the extent to which they responded to the rotation varied. Outbound ants, both close to and further from the nest, compensated for the change in the overhead e-vector by about half of the manipulation, suggesting that outbound ants choose a compromise heading between the celestial and terrestrial compass cues. However, ants returning home compensated for the change in the e-vector by about half of the manipulation when the remaining home vector was short (1-2 m) and by more than half of the manipulation when the remaining vector was long (more than 4 m). We report these findings and discuss why weighting on polarization cues change in different contexts.

  9. Prey Capture Behavior in an Arboreal African Ponerine Ant

    PubMed Central

    Dejean, Alain

    2011-01-01

    I studied the predatory behavior of Platythyrea conradti, an arboreal ponerine ant, whereas most species in this subfamily are ground-dwelling. The workers, which hunt solitarily only around dusk, are able to capture a wide range of prey, including termites and agile, nocturnal insects as well as diurnal insects that are inactive at that moment of the Nyctemeron, resting on tree branches or under leaves. Prey are captured very rapidly, and the antennal palpation used by ground-dwelling ponerine species is reduced to a simple contact; stinging occurs immediately thereafter. The venom has an instant, violent effect as even large prey (up to 30 times the weight of a worker) never struggled after being stung. Only small prey are not stung. Workers retrieve their prey, even large items, singly. To capture termite workers and soldiers defending their nest entrances, ant workers crouch and fold their antennae backward. In their role as guards, the termites face the crouching ants and end up by rolling onto their backs, their legs batting the air. This is likely due to volatile secretions produced by the ants' mandibular gland. The same behavior is used against competing ants, including territorially-dominant arboreal species that retreat further and further away, so that the P. conradti finally drive them from large, sugary food sources. PMID:21589941

  10. Consequences of prescribed fire and grazing on grassland ant communities.

    PubMed

    Underwood, Emma C; Christian, Caroline E

    2009-04-01

    Prescribed fire and livestock grazing are used for the management and restoration of native grasslands the world over; however, the effects of these management techniques on ant communities are unclear. We examined the response of ants to these disturbances in grasslands in northern California. Twenty-four 30 by 30 m plots were established across two sites that received one of four treatments: grazing, fire, grazing and fire, or no treatment. Ants were censused using 240 pitfall traps with one preburn and two postburn samples (14 d and 1 yr after burning). We analyzed ant abundance using broadly defined groups based on feeding habit and/or habitat use and detected no grazing effect but a significant fire effect that differed by group. Immediate postfire sampling showed an increase in cryptic species (particularly Brachymyrmex depilis). One year after the fire, no response was detected for cryptic species, but burned plots had greater abundance of seed harvesters. Analysis of vegetation showed burned plots had significantly greater forb cover, which might have provided greater food resources, and also lower biomass, which might have facilitated foraging. Understanding the effects of these management tools on ant abundance complements our understanding of their effect on vegetation and assists conservation practitioners effectively manage grassland ecosystems both in California and beyond.

  11. Competition can lead to unexpected patterns in tropical ant communities

    NASA Astrophysics Data System (ADS)

    Ellwood, M. D. Farnon; Blüthgen, Nico; Fayle, Tom M.; Foster, William A.; Menzel, Florian

    2016-08-01

    Ecological communities are structured by competitive, predatory, mutualistic and parasitic interactions combined with chance events. Separating deterministic from stochastic processes is possible, but finding statistical evidence for specific biological interactions is challenging. We attempt to solve this problem for ant communities nesting in epiphytic bird's nest ferns (Asplenium nidus) in Borneo's lowland rainforest. By recording the frequencies with which each and every single ant species occurred together, we were able to test statistically for patterns associated with interspecific competition. We found evidence for competition, but the resulting co-occurrence pattern was the opposite of what we expected. Rather than detecting species segregation-the classical hallmark of competition-we found species aggregation. Moreover, our approach of testing individual pairwise interactions mostly revealed spatially positive rather than negative associations. Significant negative interactions were only detected among large ants, and among species of the subfamily Ponerinae. Remarkably, the results from this study, and from a corroborating analysis of ant communities known to be structured by competition, suggest that competition within the ants leads to species aggregation rather than segregation. We believe this unexpected result is linked with the displacement of species following asymmetric competition. We conclude that analysing co-occurrence frequencies across complete species assemblages, separately for each species, and for each unique pairwise combination of species, represents a subtle yet powerful way of detecting structure and compartmentalisation in ecological communities.

  12. Stigmergic construction and topochemical information shape ant nest architecture.

    PubMed

    Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

    2016-02-02

    The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture.

  13. Neuromodulation of Nestmate Recognition Decisions by Pavement Ants.

    PubMed

    Bubak, Andrew N; Yaeger, Jazmine D W; Renner, Kenneth J; Swallow, John G; Greene, Michael J

    2016-01-01

    Ant colonies are distributed systems that are regulated in a non-hierarchical manner. Without a central authority, individuals inform their decisions by comparing information in local cues to a set of inherent behavioral rules. Individual behavioral decisions collectively change colony behavior and lead to self-organization capable of solving complex problems such as the decision to engage in aggressive societal conflicts with neighbors. Despite the relevance to colony fitness, the mechanisms that drive individual decisions leading to cooperative behavior are not well understood. Here we show how sensory information, both tactile and chemical, and social context-isolation, nestmate interaction, or fighting non-nestmates-affects brain monoamine levels in pavement ants (Tetramorium caespitum). Our results provide evidence that changes in octopamine and serotonin in the brains of individuals are sufficient to alter the decision by pavement ants to be aggressive towards non-nestmate ants whereas increased brain levels of dopamine correlate to physical fighting. We propose a model in which the changes in brain states of many workers collectively lead to the self-organization of societal aggression between neighboring colonies of pavement ants.

  14. Neuromodulation of Nestmate Recognition Decisions by Pavement Ants

    PubMed Central

    Bubak, Andrew N.; Yaeger, Jazmine D. W.; Renner, Kenneth J.; Swallow, John G.; Greene, Michael J.

    2016-01-01

    Ant colonies are distributed systems that are regulated in a non-hierarchical manner. Without a central authority, individuals inform their decisions by comparing information in local cues to a set of inherent behavioral rules. Individual behavioral decisions collectively change colony behavior and lead to self-organization capable of solving complex problems such as the decision to engage in aggressive societal conflicts with neighbors. Despite the relevance to colony fitness, the mechanisms that drive individual decisions leading to cooperative behavior are not well understood. Here we show how sensory information, both tactile and chemical, and social context—isolation, nestmate interaction, or fighting non-nestmates—affects brain monoamine levels in pavement ants (Tetramorium caespitum). Our results provide evidence that changes in octopamine and serotonin in the brains of individuals are sufficient to alter the decision by pavement ants to be aggressive towards non-nestmate ants whereas increased brain levels of dopamine correlate to physical fighting. We propose a model in which the changes in brain states of many workers collectively lead to the self-organization of societal aggression between neighboring colonies of pavement ants. PMID:27846261

  15. Polarized light use in the nocturnal bull ant, Myrmecia midas

    PubMed Central

    Lemesle, Corentin; Cheng, Ken

    2017-01-01

    Solitary foraging ants have a navigational toolkit, which includes the use of both terrestrial and celestial visual cues, allowing individuals to successfully pilot between food sources and their nest. One such celestial cue is the polarization pattern in the overhead sky. Here, we explore the use of polarized light during outbound and inbound journeys and with different home vectors in the nocturnal bull ant, Myrmecia midas. We tested foragers on both portions of the foraging trip by rotating the overhead polarization pattern by ±45°. Both outbound and inbound foragers responded to the polarized light change, but the extent to which they responded to the rotation varied. Outbound ants, both close to and further from the nest, compensated for the change in the overhead e-vector by about half of the manipulation, suggesting that outbound ants choose a compromise heading between the celestial and terrestrial compass cues. However, ants returning home compensated for the change in the e-vector by about half of the manipulation when the remaining home vector was short (1−2 m) and by more than half of the manipulation when the remaining vector was long (more than 4 m). We report these findings and discuss why weighting on polarization cues change in different contexts. PMID:28879002

  16. Spatiotemporal resource distribution and foraging strategies of ants (Hymenoptera: Formicidae)

    PubMed Central

    Lanan, Michele

    2014-01-01

    The distribution of food resources in space and time is likely to be an important factor governing the type of foraging strategy used by ants. However, no previous systematic attempt has been made to determine whether spatiotemporal resource distribution is in fact correlated with foraging strategy across the ants. In this analysis, I present data compiled from the literature on the foraging strategy and food resource use of 402 species of ants from across the phylogenetic tree. By categorizing the distribution of resources reported in these studies in terms of size relative to colony size, spatial distribution relative to colony foraging range, frequency of occurrence in time relative to worker life span, and depletability (i.e., whether the colony can cause a change in resource frequency), I demonstrate that different foraging strategies are indeed associated with specific spatiotemporal resource attributes. The general patterns I describe here can therefore be used as a framework to inform predictions in future studies of ant foraging behavior. No differences were found between resources collected via short-term recruitment strategies (group recruitment, short-term trails, and volatile recruitment), whereas different resource distributions were associated with solitary foraging, trunk trails, long-term trail networks, group raiding, and raiding. In many cases, ant species use a combination of different foraging strategies to collect diverse resources. It is useful to consider these foraging strategies not as separate options but as modular parts of the total foraging effort of a colony. PMID:25525497

  17. Density-mediated, context-dependent consumer-resource interactions between ants and extrafloral nectar plants.

    PubMed

    Chamberlain, Scott A; Holland, J Nathaniel

    2008-05-01

    Interspecific interactions are often mediated by the interplay between resource supply and consumer density. The supply of a resource and a consumer's density response to it may in turn yield context-dependent use of other resources. Such consumer-resource interactions occur not only for predator-prey and competitive interactions, but for mutualistic ones as well. For example, consumer-resource interactions between ants and extrafloral nectar (EFN) plants are often mutualistic, as EFN resources attract and reward ants which protect plants from herbivory. Yet, ants also commonly exploit floral resources, leading to antagonistic consumer-resource interactions by disrupting pollination and plant reproduction. EFN resources associated with mutualistic ant-plant interactions may also mediate antagonistic ant-flower interactions through the aggregative density response of ants on plants, which could either exacerbate ant-flower interactions or alternatively satiate and distract ants from floral resources. In this study, we examined how EFN resources mediate the density response of ants on senita cacti in the Sonoran Desert and their context-dependent use of floral resources. Removal of EFN resources reduced the aggregative density of ants on plants, both on hourly and daily time scales. Yet, the increased aggregative ant density on plants with EFN resources decreased rather than increased ant use of floral resources, including contacts with and time spent in flowers. Behavioral assays showed no confounding effect of floral deterrents on ant-flower interactions. Thus, ant use of floral resources depends on the supply of EFN resources, which mediates the potential for both mutualistic and antagonistic interactions by increasing the aggregative density of ants protecting plants, while concurrently distracting ants from floral resources. Nevertheless, only certain years and populations of study showed an increase in plant reproduction through herbivore protection or ant

  18. The scent of mixtures: rules of odour processing in ants

    PubMed Central

    Perez, Margot; Giurfa, Martin; d'Ettorre, Patrizia

    2015-01-01

    Natural odours are complex blends of numerous components. Understanding how animals perceive odour mixtures is central to multiple disciplines. Here we focused on carpenter ants, which rely on odours in various behavioural contexts. We studied overshadowing, a phenomenon that occurs when animals having learnt a binary mixture respond less to one component than to the other, and less than when this component was learnt alone. Ants were trained individually with alcohols and aldehydes varying in carbon-chain length, either as single odours or binary mixtures. They were then tested with the mixture and the components. Overshadowing resulted from the interaction between chain length and functional group: alcohols overshadowed aldehydes, and longer chain lengths overshadowed shorter ones; yet, combinations of these factors could cancel each other and suppress overshadowing. Our results show how ants treat binary olfactory mixtures and set the basis for predictive analyses of odour perception in insects. PMID:25726692

  19. Social isolation and brain development in the ant Camponotus floridanus.

    PubMed

    Seid, Marc A; Junge, Erich

    2016-06-01

    Social interactions play a key role in the healthy development of social animals and are most pronounced in species with complex social networks. When developing offspring do not receive proper social interaction, they show developmental impairments. This effect is well documented in mammalian species but controversial in social insects. It has been hypothesized that the enlargement of the mushroom bodies, responsible for learning and memory, observed in social insects is needed for maintaining the large social networks and/or task allocation. This study examines the impact of social isolation on the development of mushroom bodies of the ant Camponotus floridanus. Ants raised in isolation were shown to exhibit impairment in the growth of the mushroom bodies as well as behavioral differences when compared to ants raised in social groups. These results indicate that social interaction is necessary for the proper development of C. floridanus mushroom bodies.

  20. Predicting Flood in Perlis Using Ant Colony Optimization

    NASA Astrophysics Data System (ADS)

    Nadia Sabri, Syaidatul; Saian, Rizauddin

    2017-06-01

    Flood forecasting is widely being studied in order to reduce the effect of flood such as loss of property, loss of life and contamination of water supply. Usually flood occurs due to continuous heavy rainfall. This study used a variant of Ant Colony Optimization (ACO) algorithm named the Ant-Miner to develop the classification prediction model to predict flood. However, since Ant-Miner only accept discrete data, while rainfall data is a time series data, a pre-processing steps is needed to discretize the rainfall data initially. This study used a technique called the Symbolic Aggregate Approximation (SAX) to convert the rainfall time series data into discrete data. As an addition, Simple K-Means algorithm was used to cluster the data produced by SAX. The findings show that the predictive accuracy of the classification prediction model is more than 80%.

  1. Social isolation and brain development in the ant Camponotus floridanus

    NASA Astrophysics Data System (ADS)

    Seid, Marc A.; Junge, Erich

    2016-06-01

    Social interactions play a key role in the healthy development of social animals and are most pronounced in species with complex social networks. When developing offspring do not receive proper social interaction, they show developmental impairments. This effect is well documented in mammalian species but controversial in social insects. It has been hypothesized that the enlargement of the mushroom bodies, responsible for learning and memory, observed in social insects is needed for maintaining the large social networks and/or task allocation. This study examines the impact of social isolation on the development of mushroom bodies of the ant Camponotus floridanus. Ants raised in isolation were shown to exhibit impairment in the growth of the mushroom bodies as well as behavioral differences when compared to ants raised in social groups. These results indicate that social interaction is necessary for the proper development of C. floridanus mushroom bodies.

  2. Pericarpial nectary-visiting ants do not provide fruit protection against pre-dispersal seed predators regardless of ant species composition and resource availability

    PubMed Central

    Ré Jorge, Leonardo; Benitez-Vieyra, Santiago; Amorim, Felipe W.

    2017-01-01

    Extrafloral nectaries can occur in both vegetative and reproductive plant structures. In many Rubiaceae species in the Brazilian Cerrado, after corolla abscission, the floral nectary continues to secret nectar throughout fruit development originating post-floral pericarpial nectaries which commonly attract many ant species. The occurrence of such nectar secreting structures might be strategic for fruit protection against seed predators, as plants are expected to invest higher on more valuable and vulnerable parts. Here, we performed ant exclusion experiments to investigate whether the interaction with ants mediated by the pericarpial nectaries of Tocoyena formosa affects plant reproductive success by reducing the number of pre-dispersal seed predators. We also assessed whether ant protection was dependent on ant species composition and resource availability. Although most of the plants were visited by large and aggressive ant species, such as Ectatomma tuberculatum and species of the genus Camponotus, ants did not protect fruits against seed predators. Furthermore, the result of the interaction was neither related to ant species composition nor to the availability of resources. We suggest that these results may be related to the nature and behavior of the most important seed predators, like Hemicolpus abdominalis weevil which the exoskeleton toughness prevent it from being predated by most ant species. On the other hand, not explored factors, such as reward quality, local ant abundance, ant colony characteristics and/or the presence of alternative energetic sources could also account for variations in ant frequency, composition, and finally ant protective effects, highlighting the conditionality of facultative plant-ant mutualisms. PMID:29211790

  3. Agricultural matrices affect ground ant assemblage composition inside forest fragments.

    PubMed

    Assis, Diego Santana; Dos Santos, Iracenir Andrade; Ramos, Flavio Nunes; Barrios-Rojas, Katty Elena; Majer, Jonathan David; Vilela, Evaldo Ferreira

    2018-01-01

    The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices) on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates); sugarcane (3); and pasture (3). At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart). Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

  4. Agricultural matrices affect ground ant assemblage composition inside forest fragments

    PubMed Central

    Dos Santos, Iracenir Andrade; Ramos, Flavio Nunes; Majer, Jonathan David; Vilela, Evaldo Ferreira

    2018-01-01

    The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices) on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates); sugarcane (3); and pasture (3). At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart). Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was ‘generalist’ both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an ‘ocean of crops’. PMID:29791493

  5. Characterization of actinobacteria associated with three ant-plant mutualisms.

    PubMed

    Hanshew, Alissa S; McDonald, Bradon R; Díaz Díaz, Carol; Djiéto-Lordon, Champlain; Blatrix, Rumsaïs; Currie, Cameron R

    2015-01-01

    Ant-plant mutualisms are conspicuous and ecologically important components of tropical ecosystems that remain largely unexplored in terms of insect-associated microbial communities. Recent work has revealed that ants in some ant-plant systems cultivate fungi (Chaetothyriales) within their domatia, which are fed to larvae. Using Pseudomyrmex penetrator/Tachigali sp. from French Guiana and Petalomyrmex phylax/Leonardoxa africana and Crematogaster margaritae/Keetia hispida, both from Cameroon, as models, we tested the hypothesis that ant-plant-fungus mutualisms co-occur with culturable Actinobacteria. Using selective media, we isolated 861 putative Actinobacteria from the three systems. All C. margaritae/K. hispida samples had culturable Actinobacteria with a mean of 10.0 colony forming units (CFUs) per sample, while 26 % of P. penetrator/Tachigali samples (mean CFUs 1.3) and 67 % of P. phylax/L. africana samples (mean CFUs 3.6) yielded Actinobacteria. The largest number of CFUs was obtained from P. penetrator workers, P. phylax alates, and C. margaritae pupae. 16S rRNA gene sequencing and phylogenetic analysis revealed the presence of four main clades of Streptomyces and one clade of Nocardioides within these three ant-plant mutualisms. Streptomyces with antifungal properties were isolated from all three systems, suggesting that they could serve as protective symbionts, as found in other insects. In addition, a number of isolates from a clade of Streptomyces associated with P. phylax/L. africana and C. margaritae/K. hispida were capable of degrading cellulose, suggesting that Streptomyces in these systems may serve a nutritional role. Repeated isolation of particular clades of Actinobacteria from two geographically distant locations supports these isolates as residents in ant-plant-fungi niches.

  6. Multiple Ant Species Tending Lac Insect Kerria yunnanensis (Hemiptera: Kerriidae) Provide Asymmetric Protection against Parasitoids

    PubMed Central

    Li, Qiao; Hoffmann, Benjamin D.; Zhang, Wei

    2014-01-01

    This study investigated the effects of ant attendance on the parasitoid community and parasitism of lac insect Kerria yunnanensis aggregations in Yunnan province, China. We manipulated ant attendance to establish three treatments: (1) ant exclusion; (2) low ant attendance by several ant species; and (3) high ant attendance by Crematogaster macaoensis. Five parasitoid species were collected, with two species contributing 82.7 and 13.2% of total abundance respectively. Total parasitoid abundance was lowest in the February sample when K. yunnanensis was in its younger life stage, being significantly lower in the ant exclusion treatment. In April, all three treatments had significantly different parasitoid abundances, being highest in the ant exclusion treatment and the lowest in the high ant attendance treatment. When ants were present, there were strong negative relationships between total parasitoid abundance and ant abundance, with the relationships being dependent upon the ant species composition and abundance. The patterns of total parasitoid abundance were driven by the two most abundant parasitoid species. Parasitoid species richness did not differ among treatments or between sample times, however, multivariate analysis confirmed that overall parasitoid community structure differed significantly among treatments and between sample times, with the high ant attendance treatment differing most from the other two treatments. Interestingly the absence of ants did not result in increased parasitism from four of the five parasitoids. Ants in lac insect farming systems have a clear role for agricultural pest management. A full understanding of the asymmetric abilities of ants to influence parasitoid communities, and affect parasitism of hosts will require further experimental manipulation to assess the relative roles of 1) the abundance of each individual ant species on parasitoid access to hosts, 2) competition among parasitoids, and 3) the interaction between the

  7. Bacterial gut symbionts are tightly linked with the evolution of herbivory in ants

    PubMed Central

    Russell, Jacob A.; Moreau, Corrie S.; Goldman-Huertas, Benjamin; Fujiwara, Mikiko; Lohman, David J.; Pierce, Naomi E.

    2009-01-01

    Ants are a dominant feature of terrestrial ecosystems, yet we know little about the forces that drive their evolution. Recent findings illustrate that their diets range from herbivorous to predaceous, with “herbivores” feeding primarily on exudates from plants and sap-feeding insects. Persistence on these nitrogen-poor food sources raises the question of how ants obtain sufficient nutrition. To investigate the potential role of symbiotic microbes, we have surveyed 283 species from 18 of the 21 ant subfamilies using molecular techniques. Our findings uncovered a wealth of bacteria from across the ants. Notable among the surveyed hosts were herbivorous “turtle ants” from the related genera Cephalotes and Procryptocerus (tribe Cephalotini). These commonly harbored bacteria from ant-specific clades within the Burkholderiales, Pseudomonadales, Rhizobiales, Verrucomicrobiales, and Xanthomonadales, and studies of lab-reared Cephalotes varians characterized these microbes as symbiotic residents of ant guts. Although most of these symbionts were confined to turtle ants, bacteria from an ant-specific clade of Rhizobiales were more broadly distributed. Statistical analyses revealed a strong relationship between herbivory and the prevalence of Rhizobiales gut symbionts within ant genera. Furthermore, a consideration of the ant phylogeny identified at least five independent origins of symbioses between herbivorous ants and related Rhizobiales. Combined with previous findings and the potential for symbiotic nitrogen fixation, our results strongly support the hypothesis that bacteria have facilitated convergent evolution of herbivory across the ants, further implicating symbiosis as a major force in ant evolution. PMID:19948964

  8. Five new records of ants (Hymenoptera: Formicidae) from Morocco.

    PubMed

    Taheri, Ahmed; Reyes-López, Joaquin L

    2015-01-01

    A recent catalogue of the rich ant fauna of Morocco included 214 species, with later studies adding an additional 12 species. Following recent fieldwork in the north of Morocco, we report five new records for the country (Plagiolepis pygmaea Latreille, 1798, Ponera testacea Emery, 1895, Strumigenys tenuipilis Emery, 1915, Temnothorax pardoi Tinaut, 1987, and Tetramorium parvioculum Guillem & Bensusan, 2009) and we present new data on the distribution and natural history of six additional species. This work brings the total number of ants known from Morocco to 233, taking into account two species which were omitted in the list of Cagniant. © Crown copyright 2015.

  9. Five New Records of Ants (Hymenoptera: Formicidae) From Morocco

    PubMed Central

    Taheri, Ahmed; Reyes-López, Joaquin L.

    2015-01-01

    A recent catalogue of the rich ant fauna of Morocco included 214 species, with later studies adding an additional 12 species. Following recent fieldwork in the north of Morocco, we report five new records for the country (Plagiolepis pygmaea Latreille, 1798, Ponera testacea Emery, 1895, Strumigenys tenuipilis Emery, 1915, Temnothorax pardoi Tinaut, 1987, and Tetramorium parvioculum Guillem & Bensusan, 2009) and we present new data on the distribution and natural history of six additional species. This work brings the total number of ants known from Morocco to 233, taking into account two species which were omitted in the list of Cagniant. PMID:25843590

  10. Conflict over reproduction in an ant-plant symbiosis: why Allomerus octoarticulatus ants sterilize Cordia nodosa trees.

    PubMed

    Frederickson, Megan E

    2009-05-01

    The evolutionary stability of mutualism is thought to depend on how well the fitness interests of partners are aligned. Because most ant-myrmecophyte mutualisms are persistent and horizontally transmitted, partners share an interest in growth but not in reproduction. Resources invested in reproduction are unavailable for growth, giving rise to a conflict of interest between partners. I investigated whether this explains why Allomerus octoarticulatus ants sterilize Cordia nodosa trees. Allomerus octoarticulatus nests in the hollow stem domatia of C. nodosa. Workers protect C. nodosa leaves against herbivores but destroy inflorescences. Using C. nodosa trees with Azteca ants, which do not sterilize their hosts, I cut inflorescences off trees to simulate sterilization by A. octoarticulatus. Sterilized C. nodosa grew faster than control trees, providing evidence for a trade-off between growth and reproduction. Allomerus octoarticulatus manipulates this trade-off to its advantage; sterilized trees produce more domatia and can house larger, more fecund colonies.

  11. Impact of imidacloprid on new queens of imported fire ants, Solenopsis invicta (Hymenoptera: Formicidae)

    USDA-ARS?s Scientific Manuscript database

    Neonicotinoid insecticides are commonly used in managing pest ants, including the imported fire ant, Solenopsis invicta Buren. There is increasing evidence that neonicotinoid insecticides at sublethal concentrations have profound effects on social insects. However, the sublethal effect of neonicot...

  12. Activity of Bifenthrin, Chlorfenapyr, Fipronil, and Thiamethoxam against Argentine Ants (Hymenoptera: Formicidae)

    USDA-ARS?s Scientific Manuscript database

    Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the Argentine ant, Linepithema humile (Mayr). Mobility impairment and lethal times were determined following topical treatments. Ants were immobilized most quickly by bifenthrin, followed by chlorfenapyr and th...

  13. Activity of Bifenthrin, Chlorfenapyr, Fipronil, and Thiamethoxam against Red Imported Fire Ants (Hymenoptera: Formicidae)

    USDA-ARS?s Scientific Manuscript database

    Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the Argentine ant, Linepithema humile (Mayr). Mobility impairment and lethal times were determined following topical treatments. Ants were immobilized most quickly by bifenthrin, followed by chlorfenapyr and thi...

  14. Regulation and specificity of antifungal metapleural gland secretion in leaf-cutting ants

    PubMed Central

    Yek, Sze Huei; Nash, David R.; Jensen, Annette B.; Boomsma, Jacobus J.

    2012-01-01

    Ants have paired metapleural glands (MGs) to produce secretions for prophylactic hygiene. These exocrine glands are particularly well developed in leaf-cutting ants, but whether the ants can actively regulate MG secretion is unknown. In a set of controlled experiments using conidia of five fungi, we show that the ants adjust the amount of MG secretion to the virulence of the fungus with which they are infected. We further applied fixed volumes of MG secretion of ants challenged with constant conidia doses to agar mats of the same fungal species. This showed that inhibition halos were significantly larger for ants challenged with virulent and mild pathogens/weeds than for controls and Escovopsis-challenged ants. We conclude that the MG defence system of leaf-cutting ants has characteristics reminiscent of an additional cuticular immune system, with specific and non-specific components, of which some are constitutive and others induced. PMID:22915672

  15. Ants impact the composition of the aquatic macroinvertebrate communities of a myrmecophytic tank bromeliad.

    PubMed

    Dejean, Alain; Compin, Arthur; Leponce, Maurice; Azémar, Frédéric; Bonhomme, Camille; Talaga, Stanislas; Pelozuelo, Laurent; Hénaut, Yann; Corbara, Bruno

    2018-03-01

    In an inundated Mexican forest, 89 out of 92 myrmecophytic tank bromeliads (Aechmea bracteata) housed an associated ant colony: 13 sheltered Azteca serica, 43 Dolichoderus bispinosus, and 33 Neoponera villosa. Ant presence has a positive impact on the diversity of the aquatic macroinvertebrate communities (n=30 bromeliads studied). A Principal Component Analysis (PCA) showed that the presence and the species of ant are not correlated to bromeliad size, quantity of water, number of wells, filtered organic matter or incident radiation. The PCA and a generalized linear model showed that the presence of Azteca serica differed from the presence of the other two ant species or no ants in its effects on the aquatic invertebrate community (more predators). Therefore, both ant presence and species of ant affect the composition of the aquatic macroinvertebrate communities in the tanks of A. bracteata, likely due to ant deposition of feces and other waste in these tanks. Copyright © 2018. Published by Elsevier Masson SAS.

  16. Yellow jackets may be an underestimated component of an ant-seed mutualism

    USGS Publications Warehouse

    Bale, M.T.; Zettler, J.A.; Robinson, B.A.; Spira, T.P.; Allen, Craig R.

    2003-01-01

    Yellow jackets (Hymenoptera: Vespidae) are attracted to the typically ant-dispersed seeds of trilliums and will take seeds from ants in the genus Aphaenogaster. To determine if yellow jacket, Vespula maculifrons (Buysson), presence interferes with seed foraging by ants, we presented seeds of Trillium discolor Wray to three species (A. texana carolinensis Wheeler, Formica schaufussi Mayr, and Solenopsis invicta Buren) of seed-carrying ants in areas where vespids were present or excluded. We found that interspecific aggression between yellow jackets and ants is species specific. Vespid presence decreased average foraging time and increased foraging efficiency of two of the three ant species studied, a situation that might reflect competition for a limited food source. We also found that yellow jackets removed more seeds than ants, suggestive that vespids are important, albeit underestimated, components of ant-seed mutualisms.

  17. Verification of Argentine ant defensive compounds and their behavioral effects on heterospecific competitors and conspecific nestmates

    USDA-ARS?s Scientific Manuscript database

    The invasive Argentine ant (Linepithema humile) has become established worldwide in regions with Mediterranean or subtropical climates. The species typically disrupts the balance of natural ecosystems by competitively displacing some native ant species via strong exploitation and interference compet...

  18. Argentine ant trail pheromone disruption is mediated by trail concentration.

    PubMed

    Suckling, David Maxwell; Stringer, Lloyd D; Corn, Joshua E

    2011-10-01

    Argentine ant trail pheromone disruption, using continuous release of the trail pheromone compound (Z)-9-hexadecanal, reduces the incidence of trails and foraging rates of field populations. However, little is known about the concentrations of pheromone required for successful disruption. We hypothesized that higher pheromone quantities would be necessary to disrupt larger ant populations. To test this, we laid a 30-cm long base trail of (Z)-9-hexadecanal on a glass surface at low and high rates (1 and 100 pg/cm) (Trail 1), and laid a second, shorter trail (Trail 2, 10 cm long, located 1.5 cm upwind) near the middle of Trail 1 at six rates (1, 10, 100, 1,000, 10,000, and 100,000 pg/cm). We then recorded and digitized movements of individual ants following Trail 1, and derived a regression statistic, r (2), as an index of trail integrity, and also recorded arrival success at the other end of the trail (30 cm) near a food supply. Disruption of trails required 100 fold more pheromone upwind, independent of base-trail concentration. This implies that in the field, trail disruption is likely to be less successful against high ant-trail densities (greater concentration of trail pheromone), and more successful against newly formed or weak trails, as could be expected along invasion fronts.

  19. Evolutionary transitions in enzyme activity of ant fungus gardens.

    PubMed

    De Fine Licht, Henrik H; Schiøtt, Morten; Mueller, Ulrich G; Boomsma, Jacobus J

    2010-07-01

    Fungus-growing (attine) ants and their fungal symbionts passed through several evolutionary transitions during their 50 million year old evolutionary history. The basal attine lineages often shifted between two main cultivar clades, whereas the derived higher-attine lineages maintained an association with a monophyletic clade of specialized symbionts. In conjunction with the transition to specialized symbionts, the ants advanced in colony size and social complexity. Here we provide a comparative study of the functional specialization in extracellular enzyme activities in fungus gardens across the attine phylogeny. We show that, relative to sister clades, gardens of higher-attine ants have enhanced activity of protein-digesting enzymes, whereas gardens of leaf-cutting ants also have increased activity of starch-digesting enzymes. However, the enzyme activities of lower-attine fungus gardens are targeted primarily toward partial degradation of plant cell walls, reflecting a plesiomorphic state of nondomesticated fungi. The enzyme profiles of the higher-attine and leaf-cutting gardens appear particularly suited to digest fresh plant materials and to access nutrients from live cells without major breakdown of cell walls. The adaptive significance of the lower-attine symbiont shifts remains unclear. One of these shifts was obligate, but digestive advantages remained ambiguous, whereas the other remained facultative despite providing greater digestive efficiency.

  20. Primary tetradecenyl amines from the ant Monomorium floricola

    Treesearch

    T.H. Jones; J.A. Torres; R.R. Snelling; T.F. Spande

    1996-01-01

    In contrast to other ants in the genus Monomorium that produce cyclic amines, extracts of Monomorium floricola contain (Z)-7-tetradecenylamine (1) and (Z)-9-tetradecenylamine (2). The structures of these compounds were established from their spectral data and by comparison with synthetic 2.

  1. Ant-inspired density estimation via random walks

    PubMed Central

    Musco, Cameron; Su, Hsin-Hao

    2017-01-01

    Many ant species use distributed population density estimation in applications ranging from quorum sensing, to task allocation, to appraisal of enemy colony strength. It has been shown that ants estimate local population density by tracking encounter rates: The higher the density, the more often the ants bump into each other. We study distributed density estimation from a theoretical perspective. We prove that a group of anonymous agents randomly walking on a grid are able to estimate their density within a small multiplicative error in few steps by measuring their rates of encounter with other agents. Despite dependencies inherent in the fact that nearby agents may collide repeatedly (and, worse, cannot recognize when this happens), our bound nearly matches what would be required to estimate density by independently sampling grid locations. From a biological perspective, our work helps shed light on how ants and other social insects can obtain relatively accurate density estimates via encounter rates. From a technical perspective, our analysis provides tools for understanding complex dependencies in the collision probabilities of multiple random walks. We bound the strength of these dependencies using local mixing properties of the underlying graph. Our results extend beyond the grid to more general graphs, and we discuss applications to size estimation for social networks, density estimation for robot swarms, and random walk-based sampling for sensor networks. PMID:28928146

  2. Biogeography of Puerto Rican ants: a non-equilibrium case?

    Treesearch

    J.A. Torres; R.R. Snelling

    1997-01-01

    Ants were studied on Puerto Rico and 44 islands surrounding Puerto Rico. Habitat diversity was the best predictor of the number of species per island and the distributions of species followed a nested subset pattern. The number of extinctions per island was low, approximately 1 to 2 extinctions per island in a period of 18 years, and the rates of colonization seem to...

  3. Ant-inspired density estimation via random walks.

    PubMed

    Musco, Cameron; Su, Hsin-Hao; Lynch, Nancy A

    2017-10-03

    Many ant species use distributed population density estimation in applications ranging from quorum sensing, to task allocation, to appraisal of enemy colony strength. It has been shown that ants estimate local population density by tracking encounter rates: The higher the density, the more often the ants bump into each other. We study distributed density estimation from a theoretical perspective. We prove that a group of anonymous agents randomly walking on a grid are able to estimate their density within a small multiplicative error in few steps by measuring their rates of encounter with other agents. Despite dependencies inherent in the fact that nearby agents may collide repeatedly (and, worse, cannot recognize when this happens), our bound nearly matches what would be required to estimate density by independently sampling grid locations. From a biological perspective, our work helps shed light on how ants and other social insects can obtain relatively accurate density estimates via encounter rates. From a technical perspective, our analysis provides tools for understanding complex dependencies in the collision probabilities of multiple random walks. We bound the strength of these dependencies using local mixing properties of the underlying graph. Our results extend beyond the grid to more general graphs, and we discuss applications to size estimation for social networks, density estimation for robot swarms, and random walk-based sampling for sensor networks.

  4. Variability in individual activity bursts improves ant foraging success.

    PubMed

    Campos, Daniel; Bartumeus, Frederic; Méndez, Vicenç; Andrade, José S; Espadaler, Xavier

    2016-12-01

    Using experimental and computational methods, we study the role of behavioural variability in activity bursts (or temporal activity patterns) for individual and collective regulation of foraging in A. senilis ants. First, foraging experiments were carried out under special conditions (low densities of ants and food and absence of external cues or stimuli) where individual-based strategies are most prevalent. By using marked individuals and recording all foraging trajectories, we were then able to precisely quantify behavioural variability among individuals. Our main conclusions are that (i) variability of ant trajectories (turning angles, speed, etc.) is low compared with variability of temporal activity profiles, and (ii) this variability seems to be driven by plasticity of individual behaviour through time, rather than the presence of fixed behavioural stereotypes or specialists within the group. The statistical measures obtained from these experimental foraging patterns are then used to build a general agent-based model (ABM) which includes the most relevant properties of ant foraging under natural conditions, including recruitment through pheromone communication. Using the ABM, we are able to provide computational evidence that the characteristics of individual variability observed in our experiments can provide a functional advantage (in terms of foraging success) to the group; thus, we propose the biological basis underpinning our observations. Altogether, our study reveals the potential utility of experiments under simplified (laboratory) conditions for understanding information-gathering in biological systems. © 2016 The Author(s).

  5. A Review of the Biological Control of Fire Ants

    USDA-ARS?s Scientific Manuscript database

    The suppression of well-established invasive ants will likely require biological control by natural enemies. This approach is self-sustaining and can impact undetected or inaccessible populations that are the source of the continual presence and expansion of the invaders. There is an ongoing effor...

  6. Three spectrally distinct photoreceptors in diurnal and nocturnal Australian ants.

    PubMed

    Ogawa, Yuri; Falkowski, Marcin; Narendra, Ajay; Zeil, Jochen; Hemmi, Jan M

    2015-06-07

    Ants are thought to be special among Hymenopterans in having only dichromatic colour vision based on two spectrally distinct photoreceptors. Many ants are highly visual animals, however, and use vision extensively for navigation. We show here that two congeneric day- and night-active Australian ants have three spectrally distinct photoreceptor types, potentially supporting trichromatic colour vision. Electroretinogram recordings show the presence of three spectral sensitivities with peaks (λmax) at 370, 450 and 550 nm in the night-active Myrmecia vindex and peaks at 370, 470 and 510 nm in the day-active Myrmecia croslandi. Intracellular electrophysiology on individual photoreceptors confirmed that the night-active M. vindex has three spectral sensitivities with peaks (λmax) at 370, 430 and 550 nm. A large number of the intracellular recordings in the night-active M. vindex show unusually broad-band spectral sensitivities, suggesting that photoreceptors may be coupled. Spectral measurements at different temporal frequencies revealed that the ultraviolet receptors are comparatively slow. We discuss the adaptive significance and the probability of trichromacy in Myrmecia ants in the context of dim light vision and visual navigation. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  7. Aerial manoeuvrability in wingless gliding ants (Cephalotes atratus)

    PubMed Central

    Yanoviak, Stephen P.; Munk, Yonatan; Kaspari, Mike; Dudley, Robert

    2010-01-01

    In contrast to the patagial membranes of gliding vertebrates, the aerodynamic surfaces used by falling wingless ants to direct their aerial descent are unknown. We conducted ablation experiments to assess the relative contributions of the hindlegs, midlegs and gaster to gliding success in workers of the Neotropical arboreal ant Cephalotes atratus (Hymenoptera: Formicidae). Removal of hindlegs significantly reduced the success rate of directed aerial descent as well as the glide index for successful flights. Removal of the gaster alone did not significantly alter performance relative to controls. Equilibrium glide angles during successful targeting to vertical columns were statistically equivalent between control ants and ants with either the gaster or the hindlegs removed. High-speed video recordings suggested possible use of bilaterally asymmetric motions of the hindlegs to effect body rotations about the vertical axis during targeting manoeuvre. Overall, the control of gliding flight was remarkably robust to dramatic anatomical perturbations, suggesting effective control mechanisms in the face of adverse initial conditions (e.g. falling upside down), variable targeting decisions and turbulent wind gusts during flight. PMID:20236974

  8. Fire ant baits and biocontrol with pathogens update

    USDA-ARS?s Scientific Manuscript database

    The insect growth regulator (IGR) methoprene (isopropyl-(2E,4E,7R,S)-11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate) has been shown to have deleterious effects on red imported fire ants, Solenopsis invicta. It interferes with normal development of worker caste brood and reduces queen egg production...

  9. Caste development and evolution in ants: it's all about size.

    PubMed

    Trible, Waring; Kronauer, Daniel J C

    2017-01-01

    Female ants display a wide variety of morphological castes, including workers, soldiers, ergatoid (worker-like) queens and queens. Alternative caste development within a species arises from a variable array of genetic and environmental factors. Castes themselves are also variable across species and have been repeatedly gained and lost throughout the evolutionary history of ants. Here, we propose a simple theory of caste development and evolution. We propose that female morphology varies as a function of size, such that larger individuals possess more queen-like traits. Thus, the diverse mechanisms that influence caste development are simply mechanisms that affect size in ants. Each caste-associated trait has a unique relationship with size, producing a phenotypic space that permits some combinations of worker- and queen-like traits, but not others. We propose that castes are gained and lost by modifying the regions of this phenotypic space that are realized within a species. These modifications can result from changing the size-frequency distribution of individuals within a species, or by changing the association of tissue growth and size. We hope this synthesis will help unify the literature on caste in ants, and facilitate the discovery of molecular mechanisms underlying caste development and evolution. © 2017. Published by The Company of Biologists Ltd.

  10. ANTS: Exploring the Solar System with an Autonomous Nanotechnology Swarm

    NASA Technical Reports Server (NTRS)

    Clark, P. E.; Curtis, S.; Rilee, M.; Truszkowski, W.; Marr, G.

    2002-01-01

    ANTS (Autonomous Nano-Technology Swarm), a NASA advanced mission concept, calls for a large (1000 member) swarm of pico-class (1 kg) totally autonomous spacecraft to prospect the asteroid belt. Additional information is contained in the original extended abstract.

  11. 9 CFR 352.10 - Ante-mortem inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... to loading on the transport vehicle. (7) The transport of intact exotic animal carcasses to an... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Ante-mortem inspection. 352.10 Section 352.10 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...

  12. Recurrent bridgehead effects accelerate global alien ant spread

    Treesearch

    Cleo Bertelsmeier; Sébastien Ollier; Andrew M. Liebhold; Eckehard G. Brockerhoff; Darren Ward; Laurent Keller

    2018-01-01

    Biological invasions are a major threat to biological diversity, agriculture, and human health. To predict and prevent new invasions, it is crucial to develop a better understanding of the drivers of the invasion process. The analysis of 4,533 border interception events revealed that at least 51 different alien ant species were intercepted at US ports over a period of...

  13. Stabilities of ant nests and their adjacent soils

    NASA Astrophysics Data System (ADS)

    Echezona, B. C.; Igwe, C. A.

    2012-10-01

    Nests habour ants and termites and protect them from harsh environmental conditions. The structural stabilities of nests were studied to ascertain their relative vulnerability to environmental stresses. Arboreal-ant nests were pried from different trees, while epigeous-termite nests were excavated from soil surface within the sample area. Soils without any visible sign of ant or termite activity were also sampled 6 m away from the nests as control. Laboratory analysis result showed that irrespective of the tree hosts, the aggregate stabilities of the ant nests were lower than those of the ground termite, with nests formed on Cola nitida significantly showing lower aggregate stability (19.7%) than other antnest structures. Clay dispersion ratio, moisture content, water stable aggregate class <0.25mm and sand mass were each negatively correlated with aggregate stability, while water stable aggregate class1.00-0.50 mm gave a positive correlation. Nest structures were dominated more by water stable aggregate class >2.00 mm but path analysis demonstrated that water stable aggregate class <0.25 mm contributed most to the higher aggregate stability of the termite nest than the other nest. Nest aggregates had greater structural stability compared to the control soil. The higher structural stability of termite nests over other nest and soil was considered a better adaptive mechanism against body desiccation.

  14. Compass cues used by a nocturnal bull ant, Myrmecia midas.

    PubMed

    Freas, Cody A; Narendra, Ajay; Cheng, Ken

    2017-05-01

    Ants use both terrestrial landmarks and celestial cues to navigate to and from their nest location. These cues persist even as light levels drop during the twilight/night. Here, we determined the compass cues used by a nocturnal bull ant, Myrmecia midas , in which the majority of individuals begin foraging during the evening twilight period. Myrmecia midas foragers with vectors of ≤5   m when displaced to unfamiliar locations did not follow the home vector, but instead showed random heading directions. Foragers with larger home vectors (≥10   m) oriented towards the fictive nest, indicating a possible increase in cue strength with vector length. When the ants were displaced locally to create a conflict between the home direction indicated by the path integrator and terrestrial landmarks, foragers oriented using landmark information exclusively and ignored any accumulated home vector regardless of vector length. When the visual landmarks at the local displacement site were blocked, foragers were unable to orient to the nest direction and their heading directions were randomly distributed. Myrmecia midas ants typically nest at the base of the tree and some individuals forage on the same tree. Foragers collected on the nest tree during evening twilight were unable to orient towards the nest after small lateral displacements away from the nest. This suggests the possibility of high tree fidelity and an inability to extrapolate landmark compass cues from information collected on the tree and at the nest site to close displacement sites. © 2017. Published by The Company of Biologists Ltd.

  15. Reproductive phenologies in a diverse temperate ant fauna

    USGS Publications Warehouse

    Dunn, R.R.; Parker, C.R.; Geraghty, M.; Sanders, N.J.

    2007-01-01

    1. Ant nuptial flights are central to understanding ant life history and ecology but have been little studied. This study examined the timing of nuptial flights, the synchronicity of nuptial flights (as a potential index of mating strategy), and variation in nuptial flights with elevation and among years in a diverse temperate ant fauna. 2. Flights occurred throughout the year, but were concentrated in the beginning of summer and in early fall (autumn). Relative to the entire flight season, closely related species tended to be more likely than expected by chance to fly at similar times, perhaps because of phylogenetic constraints on life history evolution. 3. Flights were relatively synchronous within species for nearly all species considered, but synchronicity did not appear to be a robust estimate of overall mating strategy. 4. Overall patterns in nuptial flights among species and the timing of flights for individual species varied with elevation, but did not vary greatly among years. 5. Although this study is one of the most comprehensive on the reproductive flight phenologies of ants, much remains to be learned about the causes and consequences of such spatial and temporal variation in flight phenology. ?? 2007 The Royal Entomological Society.

  16. Improved Modeling of Intelligent Tutoring Systems Using Ant Colony Optimization

    ERIC Educational Resources Information Center

    Rastegarmoghadam, Mahin; Ziarati, Koorush

    2017-01-01

    Swarm intelligence approaches, such as ant colony optimization (ACO), are used in adaptive e-learning systems and provide an effective method for finding optimal learning paths based on self-organization. The aim of this paper is to develop an improved modeling of adaptive tutoring systems using ACO. In this model, the learning object is…

  17. Bat aggregation mediates the functional structure of ant assemblages.

    PubMed

    Dejean, Alain; Groc, Sarah; Hérault, Bruno; Rodriguez-Pérez, Héctor; Touchard, Axel; Céréghino, Régis; Delabie, Jacques H C; Corbara, Bruno

    2015-10-01

    In the Guianese rainforest, we examined the impact of the presence of guano in and around a bat roosting site (a cave). We used ant communities as an indicator to evaluate this impact because they occupy a central place in the functioning of tropical rainforest ecosystems and they play different roles in the food web as they can be herbivores, generalists, scavengers or predators. The ant species richness around the cave did not differ from a control sample situated 500m away. Yet, the comparison of functional groups resulted in significantly greater numbers of detritivorous fungus-growing and predatory ant colonies around the cave compared to the control, the contrary being true for nectar and honeydew feeders. The role of bats, through their guano, was shown using stable isotope analyses as we noted significantly greater δ(15)N values for the ant species captured in and around the cave compared to controls. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  18. Complete excavation and mapping of a Texas leafcutting ant nest

    Treesearch

    John C. Moser

    2006-01-01

    A medium-sized nest of the Texas leafcutting ant, Atta texana (Buckley), in northern Louisiana was excavated completely, and a three-dimensional model of its external and subterranean features was constructed. In total, 97 fungus gardens, 27 dormancy cavities, and 45 detritus cavities were located. At the lower center of the funnel-shaped nest was a...

  19. Water Stress Strengthens Mutualism Among Ants, Trees, and Scale Insects

    PubMed Central

    Pringle, Elizabeth G.; Akçay, Erol; Raab, Ted K.; Dirzo, Rodolfo; Gordon, Deborah M.

    2013-01-01

    Abiotic environmental variables strongly affect the outcomes of species interactions. For example, mutualistic interactions between species are often stronger when resources are limited. The effect might be indirect: water stress on plants can lead to carbon stress, which could alter carbon-mediated plant mutualisms. In mutualistic ant–plant symbioses, plants host ant colonies that defend them against herbivores. Here we show that the partners' investments in a widespread ant–plant symbiosis increase with water stress across 26 sites along a Mesoamerican precipitation gradient. At lower precipitation levels, Cordia alliodora trees invest more carbon in Azteca ants via phloem-feeding scale insects that provide the ants with sugars, and the ants provide better defense of the carbon-producing leaves. Under water stress, the trees have smaller carbon pools. A model of the carbon trade-offs for the mutualistic partners shows that the observed strategies can arise from the carbon costs of rare but extreme events of herbivory in the rainy season. Thus, water limitation, together with the risk of herbivory, increases the strength of a carbon-based mutualism. PMID:24223521

  20. VideoANT: Extending Online Video Annotation beyond Content Delivery

    ERIC Educational Resources Information Center

    Hosack, Bradford

    2010-01-01

    This paper expands the boundaries of video annotation in education by outlining the need for extended interaction in online video use, identifying the challenges faced by existing video annotation tools, and introducing Video-ANT, a tool designed to create text-based annotations integrated within the time line of a video hosted online. Several…

  1. Vision for navigation: What can we learn from ants?

    PubMed

    Graham, Paul; Philippides, Andrew

    2017-09-01

    The visual systems of all animals are used to provide information that can guide behaviour. In some cases insects demonstrate particularly impressive visually-guided behaviour and then we might reasonably ask how the low-resolution vision and limited neural resources of insects are tuned to particular behavioural strategies. Such questions are of interest to both biologists and to engineers seeking to emulate insect-level performance with lightweight hardware. One behaviour that insects share with many animals is the use of learnt visual information for navigation. Desert ants, in particular, are expert visual navigators. Across their foraging life, ants can learn long idiosyncratic foraging routes. What's more, these routes are learnt quickly and the visual cues that define them can be implemented for guidance independently of other social or personal information. Here we review the style of visual navigation in solitary foraging ants and consider the physiological mechanisms that underpin it. Our perspective is to consider that robust navigation comes from the optimal interaction between behavioural strategy, visual mechanisms and neural hardware. We consider each of these in turn, highlighting the value of ant-like mechanisms in biomimetic endeavours. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  2. Application of cellular automatons and ant algorithms in avionics

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. V.; Selvesiuk, N. I.; Platoshin, G. A.; Semenova, E. V.

    2018-03-01

    The paper considers two algorithms for searching quasi-optimal solutions of discrete optimization problems with regard to the tasks of avionics placing. The first one solves the problem of optimal placement of devices by installation locations, the second one is for the problem of finding the shortest route between devices. Solutions are constructed using a cellular automaton and the ant colony algorithm.

  3. Mapping the navigational knowledge of individually foraging ants, Myrmecia croslandi

    PubMed Central

    Narendra, Ajay; Gourmaud, Sarah; Zeil, Jochen

    2013-01-01

    Ants are efficient navigators, guided by path integration and visual landmarks. Path integration is the primary strategy in landmark-poor habitats, but landmarks are readily used when available. The landmark panorama provides reliable information about heading direction, routes and specific location. Visual memories for guidance are often acquired along routes or near to significant places. Over what area can such locally acquired memories provide information for reaching a place? This question is unusually approachable in the solitary foraging Australian jack jumper ant, since individual foragers typically travel to one or two nest-specific foraging trees. We find that within 10 m from the nest, ants both with and without home vector information available from path integration return directly to the nest from all compass directions, after briefly scanning the panorama. By reconstructing panoramic views within the successful homing range, we show that in the open woodland habitat of these ants, snapshot memories acquired close to the nest provide sufficient navigational information to determine nest-directed heading direction over a surprisingly large area, including areas that animals may have not visited previously. PMID:23804615

  4. Diversity and distribution of ant communities in Puerto Rico

    Treesearch

    J.A. Torres

    1984-01-01

    I studied ants in upland tropical forest, grassland and agricultural land in San Lorenzo, Puerto Rico, to uncover factors responsible for the distribution and number of species in these communities. Observations, laboratory studies and field experiments were used. Microclimate influenced the distributions of Pheidole fallax, Solenopsis geminata and Monomorium ebeninum...

  5. Bilingualism Aids Conflict Resolution: Evidence from the ANT Task

    ERIC Educational Resources Information Center

    Costa, Albert; Hernandez, Mirea; Sebastian-Galles, Nuria

    2008-01-01

    The need of bilinguals to continuously control two languages during speech production may exert general effects on their attentional networks. To explore this issue we compared the performance of bilinguals and monolinguals in the attentional network task (ANT) developed by Fan et al. [Fan, J., McCandliss, B.D. Sommer, T., Raz, A., Posner, M.I.…

  6. Textural defect detect using a revised ant colony clustering algorithm

    NASA Astrophysics Data System (ADS)

    Zou, Chao; Xiao, Li; Wang, Bingwen

    2007-11-01

    We propose a totally novel method based on a revised ant colony clustering algorithm (ACCA) to explore the topic of textural defect detection. In this algorithm, our efforts are mainly made on the definition of local irregularity measurement and the implementation of the revised ACCA. The local irregular measurement defined evaluates the local textural inconsistency of each pixel against their mini-environment. In our revised ACCA, the behaviors of each ant are divided into two steps: release pheromone and act. The quantity of pheromone released is proportional to the irregularity measurement; the actions of the ants to act next are chosen independently of each other in a stochastic way according to some evaluated heuristic knowledge. The independency of ants implies the inherent parallel computation architecture of this algorithm. We apply the proposed method in some typical textural images with defects. From the series of pheromone distribution map (PDM), it can be clearly seen that the pheromone distribution approaches the textual defects gradually. By some post-processing, the final distribution of pheromone can demonstrate the shape and area of the defects well.

  7. Drowning out the protection racket: partner manipulation or drought can strengthen ant-plant mutualism.

    PubMed

    Denison, R Ford

    2014-07-01

    Two recent reports discuss interactions between plants and ants that defend them from herbivores. Acacia trees provide their ant bodyguards with a diet that reduces their ability to benefit from alternate hosts. Provisioning of ants by Cordia trees during drought may buy insurance against extreme defoliation events, not just average-year benefits. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. ANTS AS BIOLOGICAL INDICATORS FOR MONITORING CHANGES IN ARID ENVIRONMENTS: LESSONS FOR MONITORING PROTECTED AREAS

    EPA Science Inventory

    The responses of ant communities to structural change (removal of an invasive
    were studied in a replicated experiment in a Chihuahuan Desert grassland. The
    results from sampling of ant communities by pit-fall trapping were validated by
    mapping ant colonies on the expe...

  9. ANTS AS BIOLOGICAL INDICATORS FOR MONITORING CHANGES IN ARID ENVIRONMENTS: LESSONS FOR MONITORING PROTECTED AREAS

    EPA Science Inventory

    The responses of ant communities to structural change (removal of an invasive were studied in a replicated experiment in a Chihuahuan Desert grassland. The results from sampling of ant communities by pit-fall trapping were validated by mapping ant colonies on the experimental plo...

  10. LIVESTOCK GRAZING EFFECTS ON ANT COMMUNITIES IN THE EASTERN MOJAVE DESERT, USA

    EPA Science Inventory

    The effects of livestock grazing on composition and structure of ant communities were examined in the eastern Mojave Desert, USA for the purpose of evaluating ant communities as potential indicators of rangeland condition. Metrics for ant communities, vegetation, and other groun...

  11. COMPARISON OF ANOVA AND KRIGING IN DETECTING ANT RESPONSES TO ENVIRONMENTAL STRESSORS

    EPA Science Inventory

    In an ecosystems, ants effect ecosystem functions such as water infiltration, soil nutrient distribution and composition of the soil seed bank. Ants have also been used as indicators of ecosystems health. In a study, we hypothesized that some ant species would respond to changes ...

  12. Tallgrass prairie ants: their species composition, ecological roles, and response to management

    USDA-ARS?s Scientific Manuscript database

    Ants are highly influential organisms in terrestrial ecosystems, including the tallgrass prairie, one of the most endangered ecosystems in North America. Through their tunneling, ants affect soil properties and resource availability for animals and plants. Ants also have important ecological roles a...

  13. 9 CFR 354.123 - Segregation of suspects on ante-mortem inspection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Segregation of suspects on ante-mortem inspection. 354.123 Section 354.123 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... Inspection Procedures; Ante-Mortem Inspections § 354.123 Segregation of suspects on ante-mortem inspection...

  14. 9 CFR 354.123 - Segregation of suspects on ante-mortem inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Segregation of suspects on ante-mortem inspection. 354.123 Section 354.123 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... Inspection Procedures; Ante-Mortem Inspections § 354.123 Segregation of suspects on ante-mortem inspection...

  15. Some effects of predaceous birds and ants on the western spruce budworm on conifer seedlings.

    Treesearch

    Robert W. Campbell; Clinton E. Carlson; Leon J. Theroux; Thomas H. Egan

    1984-01-01

    Effects of predaceous birds and ants on the western spruce budworm, Choristoneura occidentalis, were studied on seedlings of western larch and Douglas-fir in western Montana. On western larch, both birds and ants reduced survival of larval budworm (instars IV-VI). On Douglas-fir, larval survival on one site was reduced by ants but not by birds. On a second site,...

  16. 78 FR 70530 - Notice of Determination; New and Revised Treatments for the Imported Fire Ant Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-26

    ...] Notice of Determination; New and Revised Treatments for the Imported Fire Ant Program AGENCY: Animal and... adding or revising certain treatment schedules for the Imported Fire Ant Program in the Plant Protection... imported fire ant program. Based on the treatment evaluation document, the environmental assessment, and...

  17. Estimating ladybird predation of aphids in the presence of foraging ants in lab bioassays

    USDA-ARS?s Scientific Manuscript database

    Foraging or tending ants often disrupt ladybird beetle predation of aphids on crop plants. In this study, we assessed the foraging behavior of the red imported fire ant (Solenopsis invicta) and tested the hypothesis that foraging ants disrupt ladybird predation. We setup experiments in the laborator...

  18. PsANT, the adenine nucleotide translocase of Puccinia striiformis, promotes cell death and fungal growth

    PubMed Central

    Tang, Chunlei; Wei, Jinping; Han, Qingmei; Liu, Rui; Duan, Xiaoyuan; Fu, Yanping; Huang, Xueling; Wang, Xiaojie; Kang, Zhensheng

    2015-01-01

    Adenine nucleotide translocase (ANT) is a constitutive mitochondrial component that is involved in ADP/ATP exchange and mitochondrion-mediated apoptosis in yeast and mammals. However, little is known about the function of ANT in pathogenic fungi. In this study, we identified an ANT gene of Puccinia striiformis f. sp. tritici (Pst), designated PsANT. The PsANT protein contains three typical conserved mitochondrion-carrier-protein (mito-carr) domains and shares more than 70% identity with its orthologs from other fungi, suggesting that ANT is conserved in fungi. Immuno-cytochemical localization confirmed the mitochondrial localization of PsANT in normal Pst hyphal cells or collapsed cells. Over-expression of PsANT indicated that PsANT promotes cell death in tobacco, wheat and fission yeast cells. Further study showed that the three mito-carr domains are all needed to induce cell death. qRT-PCR analyses revealed an in-planta induced expression of PsANT during infection. Knockdown of PsANT using a host-induced gene silencing system (HIGS) attenuated the growth and development of virulent Pst at the early infection stage but not enough to alter its pathogenicity. These results provide new insight into the function of PsANT in fungal cell death and growth and might be useful in the search for and design of novel disease control strategies. PMID:26058921

  19. Short-term effects of fire on Sky Island ant communities

    Treesearch

    Elliot B. Wilkinson; Edward G. Lebrun; Mary Lou Spencer; Caroline Whitby; Chris Kleine

    2005-01-01

    Few studies investigating effects of fire on ant communities have been conducted worldwide, and none in the biologically diverse and fire prone region of the Sky Islands. Ant genera richness and total abundance are significantly higher in burned areas. Ant community structure changes between unburned and burned sites, implying that disturbance may influence the role of...

  20. Glass-like dynamics in confined and congested ant traffic.

    PubMed

    Gravish, Nick; Gold, Gregory; Zangwill, Andrew; Goodisman, Michael A D; Goldman, Daniel I

    2015-09-07

    The collective movement of animal groups often occurs in confined spaces. As animal groups are challenged to move at high density, their mobility dynamics may resemble the flow of densely packed non-living soft materials such as colloids, grains, or polymers. However, unlike inert soft-materials, self-propelled collective living systems often display social interactions whose influence on collective mobility are only now being explored. In this paper, we study the mobility of bi-directional traffic flow in a social insect (the fire ant Solenopsis invicta) as we vary the diameter of confining foraging tunnels. In all tunnel diameters, we observe the emergence of spatially heterogeneous regions of fast and slow traffic that are induced through two phenomena: physical obstruction, arising from the inability of individual ants to interpenetrate, and time-delay resulting from social interaction in which ants stop to briefly antennate. Density correlation functions reveal that the relaxation dynamics of high density traffic fluctuations scale linearly with fluctuation size and are sensitive to tunnel diameter. We separate the roles of physical obstruction and social interactions in traffic flow using cellular automata based simulation. Social interaction between ants is modeled as a dwell time (Tint) over which interacting ants remain stationary in the tunnel. Investigation over a range of densities and Tint reveals that the slowing dynamics of collective motion in social living systems are consistent with dynamics near a fragile glass transition in inert soft-matter systems. In particular, flow is relatively insensitive to density until a critical density is reached. As social interaction affinity is increased (increasing Tint) traffic dynamics change and resemble a strong glass transition. Thus, social interactions play an important role in the mobility of collective living systems at high density. Our experiments and model demonstrate that the concepts of soft

  1. Temperature limits trail following behaviour through pheromone decay in ants

    NASA Astrophysics Data System (ADS)

    van Oudenhove, Louise; Billoir, Elise; Boulay, Raphaël; Bernstein, Carlos; Cerdá, Xim

    2011-12-01

    In Mediterranean habitats, temperature affects both ant foraging behaviour and community structure. Many studies have shown that dominant species often forage at lower temperature than subordinates. Yet, the factors that constrain dominant species foraging activity in hot environments are still elusive. We used the dominant ant Tapinoma nigerrimum as a model species to test the hypothesis that high temperatures hinder trail following behaviour by accelerating pheromone degradation. First, field observations showed that high temperatures (> 30°C) reduce the foraging activity of T. nigerrimum independently of the daily and seasonal rhythms of this species. Second, we isolated the effect of high temperatures on pheromone trail efficacy from its effect on worker physiology. A marked substrate was heated during 10 min (five temperature treatments from 25°C to 60°C), cooled down to 25°C, and offered in a test choice to workers. At hot temperature treatments (>40°C), workers did not discriminate the previously marked substrate. High temperatures appeared therefore to accelerate pheromone degradation. Third, we assessed the pheromone decay dynamics by a mechanistic model fitted with Bayesian inference. The model predicted ant choice through the evolution of pheromone concentration on trails as a function of both temperature and time since pheromone deposition. Overall, our results highlighted that the effect of high temperatures on recruitment intensity was partly due to pheromone evaporation. In the Mediterranean ant communities, this might affect dominant species relying on chemical recruitment, more than subordinate ant species, less dependent on chemical communication and less sensitive to high temperatures.

  2. Ant Abundance along a Productivity Gradient: Addressing Two Conflicting Hypotheses

    PubMed Central

    Segev, Udi; Kigel, Jaime; Lubin, Yael; Tielbörger, Katja

    2015-01-01

    The number of individuals within a population or community and their body size can be associated with changes in resource supply. While these relationships may provide a key to better understand the role of abiotic vs. biotic constraints in animal communities, little is known about the way size and abundance of organisms change along resource gradients. Here, we studied this interplay in ants, addressing two hypotheses with opposite predictions regarding variation in population densities along resource gradients- the ‘productivity hypothesis’ and the ‘productivity-based thinning hypothesis’. The hypotheses were tested in two functional groups of ground-dwelling ants that are directly primary consumers feeding on seeds: specialized seed-eaters and generalist species. We examined variations in colony density and foraging activity (a size measurement of the forager caste) in six ant assemblages along a steep productivity gradient in a semi-arid region, where precipitation and plant biomass vary 6-fold over a distance of 250km. An increase in the density or foraging activity of ant colonies along productivity gradients is also likely to affect competitive interactions among colonies, and consequently clinal changes in competition intensity were also examined. Ant foraging activity increased with productivity for both functional groups. However, colony density revealed opposing patterns: it increased with productivity for the specialized seed-eaters, but decreased for the generalist species. Competition intensity, evaluated by spatial partitioning of species at food baits and distribution of colonies, was uncorrelated with productivity in the specialized seed-eaters, but decreased with increasing productivity in the generalists. Our results provide support for two contrasting hypotheses regarding the effect of resource availability on the abundance of colonial organisms- the ‘productivity hypothesis’ for specialized seed-eaters and the

  3. Leaf volatile compounds and the distribution of ant patrollingin an ant-plant protection mutualism: Preliminary results on Leonardoxa (Fabaceae: Caesalpinioideae) and Petalomyrmex(Formicidae: Formicinae)

    NASA Astrophysics Data System (ADS)

    Brouat, Carine; McKey, Doyle; Bessière, Jean-Marie; Pascal, Laurence; Hossaert-McKey, Martine

    2000-12-01

    While observations suggest that plant chemicals could be important in maintaining the specificity and permitting the functioning of ant-plant symbioses, they have been little studied. We report here the strongest evidence yet for chemical signalling between ants and plants in a specific ant-plant protection symbiosis. In the mutualism between Leonardoxa africana subsp. africana and Petalomyrmex phylax, ants continuously patrol young leaves, which are vulnerable to attacks by phytophagous insects. We provide experimental evidence for chemical mediation of ant attraction to young leaves in this system. By a comparative analysis of the related non-myrmecophytic tree L. africana subsp. gracilicaulis, we identify likely candidates for attractant molecules, and suggest they may function not only as signals but also as resources. We also propose hypotheses on the evolutionary origin of these plant volatiles, and of the responses to them by mutualistic ants.

  4. A synoptic review of the ant genera (Hymenoptera, Formicidae) of the Philippines

    PubMed Central

    General, David M.; Alpert, Gary D.

    2012-01-01

    Abstract An overview of the history of myrmecology in the Philippine archipelago is presented. Keys are provided to the 11 ant subfamilies and the 92 ant genera known from the Philippines. Eleven ant genera (12%), including 3 undescribed genera, are recorded for the first time from the Philippines. The biology and ecology of the 92 genera, illustrated by full-face and profile photo-images, of Philippine ants are summarized in the form of brief generic accounts. A bibliography of significant taxonomic and behavioral papers on Philippine ants and a checklist of valid species and subspecies and their island distributions are provided. PMID:22767999

  5. A synoptic review of the ant genera (Hymenoptera, Formicidae) of the Philippines.

    PubMed

    General, David M; Alpert, Gary D

    2012-01-01

    An overview of the history of myrmecology in the Philippine archipelago is presented. Keys are provided to the 11 ant subfamilies and the 92 ant genera known from the Philippines. Eleven ant genera (12%), including 3 undescribed genera, are recorded for the first time from the Philippines. The biology and ecology of the 92 genera, illustrated by full-face and profile photo-images, of Philippine ants are summarized in the form of brief generic accounts. A bibliography of significant taxonomic and behavioral papers on Philippine ants and a checklist of valid species and subspecies and their island distributions are provided.

  6. Electric ants: A cross-disciplinary approach to understanding insect behavior

    SciTech Connect

    Slowik, T.J.; Thorvilson, H.G.; Green, B.L.

    1996-12-31

    The response and attraction of the red imported fire ant, Solenopsis invicta, to electrical equipment was examined using an interdisciplinary approach. Entomologists specializing in fire ant behavior combined expertise with electrical engineers to investigate the economically damaging interaction of fire ants with electrical circuitry. Knowledge from the realms of physics, engineering, and biology were integrated in experimentation to test for a fire ant response to electric fields and magnetic fields associated with electrical equipment. It was determined that fire ants react to electrified conductive material and the alternating-current magnetic fields associated with electricity.

  7. Elevated atmospheric carbon dioxide concentrations promote ant tending of aphids.

    PubMed

    Kremer, Jenni M M; Nooten, Sabine S; Cook, James M; Ryalls, James M W; Barton, Craig V M; Johnson, Scott N

    2018-04-27

    Animal mutualisms, which involve beneficial interactions between individuals of different species, are common in nature. Insect-insect mutualism, for example, is widely regarded as a keystone ecological interaction. Some mutualisms are anticipated to be modified by climate change, but the focus has largely been on plant-microbe and plant-animal mutualisms rather than those between animals. Ant-aphid mutualisms, whereby ants tend aphids to harvest their honeydew excretions and, in return, provide protection for the aphids, are widespread. The mutualism is heavily influenced by the quality and quantity of honeydew produced by aphids, which is directly affected by host plant quality. As predicted increases in concentrations of atmospheric carbon dioxide (eCO 2 ) are widely reported to affect plant nutritional chemistry, this may also alter honeydew quality and hence the nature of ant-aphid mutualisms. Using glasshouse chambers and field-based open-top chambers, we determined the effect of eCO 2 on the growth and nutritional quality (foliar amino acids) of lucerne (Medicago sativa). We determined how cowpea aphid (Aphis craccivora) populations and honeydew production were impacted when feeding on such plants and how this affected the tending behaviour of ants (Iridomyrmex sp.). eCO 2 stimulated plant growth but decreased concentrations of foliar amino acids by 29% and 14% on aphid-infested plants and aphid-free plants, respectively. Despite the deterioration in host plant quality under eCO 2 , aphids maintained performance and populations were unchanged by eCO 2 . Aphids induced higher concentrations of amino acids (glutamine, asparagine, glutamic acid and aspartic acid) important for endosymbiont-mediated synthesis of essential amino acids. Aphids feeding under eCO 2 also produced over three times more honeydew than aphids feeding under ambient CO 2 , suggesting they were imbibing more phloem sap at eCO 2 . The frequency of ant tending of aphids more than doubled in

  8. The Impact of Coffee and Pasture Agriculture on Predatory and Omnivorous Leaf-Litter Ants

    PubMed Central

    Dias, Nivia da Silva; Zanetti, Ronald; Santos, Mônica Silva; Peñaflor, Maria Fernanda Gomes Villalba; Broglio, Sônia Maria Forti; Delabie, Jacques Hubert Charles

    2013-01-01

    Ants are known to function as reliable biological indicators for habitat impact assessment. They play a wide range of ecological roles depending on their feeding and nesting habits. By clustering ants in guilds, it is possible both to assess how agriculture and forest fragmentation can disturb ant communities and to predict the ecological impacts due to losses of a specific guild. This study aimed at determining the impact of non-shaded coffee and pasture agriculture on predatory and omnivorous guilds of leaf-litter ants of Atlantic Forest fragments in Minas Gerais, Brazil. Both coffee and pasture agriculture influenced leaf-litter ant community, although coffee was more disruptive than pasture. Coffee agriculture not only disturbed the diversity of predatory ants, but also negatively affected the number of predatory and omnivorous ants when compared to forest fragments. In contrast, pasture agriculture only disrupted the abundance of predatory ants. Fragment edges skirting crops were negatively affected in terms of leaf-litter ant abundance, but not diversity. Cluster analysis showed that forest fragments were similar irrespective of the cultivation, but the borders were similar to the crop. The study assessed agriculture impact by surveying ant guilds, and revealed that the predatory guild is more susceptible than omnivorous ants. PMID:23902334

  9. Specific, non-nutritional association between an ascomycete fungus and Allomerus plant-ants.

    PubMed

    Ruiz-González, Mario X; Malé, Pierre-Jean G; Leroy, Céline; Dejean, Alain; Gryta, Hervé; Jargeat, Patricia; Quilichini, Angélique; Orivel, Jérôme

    2011-06-23

    Ant-fungus associations are well known from attine ants, whose nutrition is based on a symbiosis with basidiomycete fungi. Otherwise, only a few non-nutritional ant-fungus associations have been recorded to date. Here we focus on one of these associations involving Allomerus plant-ants that build galleried structures on their myrmecophytic hosts in order to ambush prey. We show that this association is not opportunistic because the ants select from a monophyletic group of closely related fungal haplotypes of an ascomycete species from the order Chaetothyriales that consistently grows on and has been isolated from the galleries. Both the ants' behaviour and an analysis of the genetic population structure of the ants and the fungus argue for host specificity in this interaction. The ants' behaviour reveals a major investment in manipulating, growing and cleaning the fungus. A molecular analysis of the fungus demonstrates the widespread occurrence of one haplotype and many other haplotypes with a lower occurrence, as well as significant variation in the presence of these fungal haplotypes between areas and ant species. Altogether, these results suggest that such an interaction might represent an as-yet undescribed type of specific association between ants and fungus in which the ants cultivate fungal mycelia to strengthen their hunting galleries.

  10. The impact of coffee and pasture agriculture on predatory and omnivorous leaf-litter ants.

    PubMed

    Dias, Nivia da Silva; Zanetti, Ronald; Santos, Mônica Silva; Peñaflor, Maria Fernanda Gomes Villalba; Broglio, Sônia Maria Forti; Delabie, Jacques Hubert Charles

    2013-01-01

    Ants are known to function as reliable biological indicators for habitat impact assessment. They play a wide range of ecological roles depending on their feeding and nesting habits. By clustering ants in guilds, it is possible both to assess how agriculture and forest fragmentation can disturb ant communities and to predict the ecological impacts due to losses of a specific guild. This study aimed at determining the impact of non-shaded coffee and pasture agriculture on predatory and omnivorous guilds of leaf-litter ants of Atlantic Forest fragments in Minas Gerais, Brazil. Both coffee and pasture agriculture influenced leaf-litter ant community, although coffee was more disruptive than pasture. Coffee agriculture not only disturbed the diversity of predatory ants, but also negatively affected the number of predatory and omnivorous ants when compared to forest fragments. In contrast, pasture agriculture only disrupted the abundance of predatory ants. Fragment edges skirting crops were negatively affected in terms of leaf-litter ant abundance, but not diversity. Cluster analysis showed that forest fragments were similar irrespective of the cultivation, but the borders were similar to the crop. The study assessed agriculture impact by surveying ant guilds, and revealed that the predatory guild is more susceptible than omnivorous ants.

  11. Tetramorium tsushimae Ants Use Methyl Branched Hydrocarbons of Aphids for Partner Recognition.

    PubMed

    Sakata, Itaru; Hayashi, Masayuki; Nakamuta, Kiyoshi

    2017-10-01

    In mutualisms, partner discrimination is often the most important challenge for interacting organisms. The interaction between ants and aphids is a model system for studying mutualisms; ants are provided with honeydew by aphids and, in turn, the ants offer beneficial services to the aphids. To establish and maintain this system, ants must discriminate mutualistic aphid species correctly. Although recent studies have shown that ants recognize aphids as mutualistic partners based on their cuticular hydrocarbons (CHCs), it was unclear which CHCs are involved in recognition. Here, we tested whether the n-alkane or methylalkane fraction, or both, of aphid CHCs were utilized as partner recognition cues by measuring ant aggressiveness toward these fractions. When workers of Tetramorium tsushimae ants were presented with dummies coated with n-alkanes of their mutualistic aphid Aphis craccivora, ants displayed higher levels of aggression than to dummies treated with total CHCs or methyl alkanes of A. craccivora; responses to dummies treated with n-alkanes of A. craccivora were similar to those to control dummies or dummies treated with the CHCs of the non-mutualistic aphid Acyrthosiphon pisum. By contrast, ants exhibited lower aggression to dummies treated with either total CHCs or the methylalkane fraction of the mutualistic aphid than to control dummies or dummies treated with CHCs of the non-mutualistic aphid. These results suggest that T. tsushimae ants use methylalkanes of the mutualistic aphid's CHCs to recognize partners, and that these ants do not recognize aphids as partners on the basis of n-alkanes.

  12. Heat-induced symmetry breaking in ant (Hymenoptera: Formicidae) escape behavior

    PubMed Central

    Chung, Yuan-Kai

    2017-01-01

    The collective egress of social insects is important in dangerous situations such as natural disasters or enemy attacks. Some studies have described the phenomenon of symmetry breaking in ants, with two exits induced by a repellent. However, whether symmetry breaking occurs under high temperature conditions, which are a common abiotic stress, remains unknown. In our study, we deposited a group of Polyrhachis dives ants on a heated platform and counted the number of escaping ants with two identical exits. We discovered that ants asymmetrically escaped through two exits when the temperature of the heated platform was >32.75°C. The degree of asymmetry increased linearly with the temperature of the platform. Furthermore, the higher the temperature of heated platform was, the more ants escaped from the heated platform. However, the number of escaping ants decreased for 3 min when the temperature was higher than the critical thermal limit (39.46°C), which is the threshold for ants to endure high temperature without a loss of performance. Moreover, the ants tended to form small groups to escape from the thermal stress. A preparatory formation of ant grouping was observed before they reached the exit, indicating that the ants actively clustered rather than accidentally gathered at the exits to escape. We suggest that a combination of individual and grouping ants may help to optimize the likelihood of survival during evacuation. PMID:28355235

  13. A phylogenetic perspective on the association between ants (Hymenoptera: Formicidae) and black yeasts (Ascomycota: Chaetothyriales).

    PubMed

    Vasse, Marie; Voglmayr, Hermann; Mayer, Veronika; Gueidan, Cécile; Nepel, Maximilian; Moreno, Leandro; de Hoog, Sybren; Selosse, Marc-André; McKey, Doyle; Blatrix, Rumsaïs

    2017-03-15

    The frequency and the geographical extent of symbiotic associations between ants and fungi of the order Chaetothyriales have been highlighted only recently. Using a phylogenetic approach based on seven molecular markers, we showed that ant-associated Chaetothyriales are scattered through the phylogeny of this order. There was no clustering according to geographical origin or to the taxonomy of the ant host. However, strains tended to be clustered according to the type of association with ants: strains from ant-made carton and strains from plant cavities occupied by ants ('domatia') rarely clustered together. Defining molecular operational taxonomic units (MOTUs) with an internal transcribed spacer sequence similarity cut-off of 99% revealed that a single MOTU could be composed of strains collected from various ant species and from several continents. Some ant-associated MOTUs also contained strains isolated from habitats other than ant-associated structures. Altogether, our results suggest that the degree of specialization of the interactions between ants and their fungal partners is highly variable. A better knowledge of the ecology of these interactions and a more comprehensive sampling of the fungal order are needed to elucidate the evolutionary history of mutualistic symbioses between ants and Chaetothyriales. © 2017 The Author(s).

  14. Absence of jamming in ant trails: feedback control of self-propulsion and noise.

    PubMed

    Chaudhuri, Debasish; Nagar, Apoorva

    2015-01-01

    We present a model of ant traffic considering individual ants as self-propelled particles undergoing single-file motion on a one-dimensional trail. Recent experiments on unidirectional ant traffic in well-formed natural trails showed that the collective velocity of ants remains approximately unchanged, leading to the absence of jamming even at very high densities [John et al., Phys. Rev. Lett. 102, 108001 (2009)]. Assuming a feedback control mechanism of self-propulsion force generated by each ant using information about the distance from the ant in front, our model captures all the main features observed in the experiment. The distance headway distribution shows a maximum corresponding to separations within clusters. The position of this maximum remains independent of average number density. We find a non-equilibrium first-order transition, with the formation of an infinite cluster at a threshold density where all the ants in the system suddenly become part of a single cluster.

  15. A novel interference behaviour: invasive wasps remove ants from resources and drop them from a height

    PubMed Central

    Grangier, Julien; Lester, Philip J.

    2011-01-01

    This study reports a novel form of interference behaviour between the invasive wasp Vespula vulgaris and the New Zealand native ant Prolasius advenus. By videotaping interactions at bait stations, we found that wasps commonly remove ant competitors from food resources by picking up the workers in their mandibles, flying backward and dropping them unharmed some distance from the food. Both the frequency and the efficiency of the wasp behaviour significantly increased with the abundance of ant competitors. Ant removals were the most common interference events initiated by wasps when ants were numerous, while intraspecific conflicts among wasps were prominent when few ants were present. The ‘ant-dropping’ behaviour emphasizes how asymmetry in body sizes between competitors can lead to a pronounced form of interference, related to asymmetric locomotion modes. PMID:21450726

  16. Cryptic termites avoid predatory ants by eavesdropping on vibrational cues from their footsteps.

    PubMed

    Oberst, Sebastian; Bann, Glen; Lai, Joseph C S; Evans, Theodore A

    2017-02-01

    Eavesdropping has evolved in many predator-prey relationships. Communication signals of social species may be particularly vulnerable to eavesdropping, such as pheromones produced by ants, which are predators of termites. Termites communicate mostly by way of substrate-borne vibrations, which suggest they may be able to eavesdrop, using two possible mechanisms: ant chemicals or ant vibrations. We observed termites foraging within millimetres of ants in the field, suggesting the evolution of specialised detection behaviours. We found the termite Coptotermes acinaciformis detected their major predator, the ant Iridomyrmex purpureus, through thin wood using only vibrational cues from walking, and not chemical signals. Comparison of 16 termite and ant species found the ants-walking signals were up to 100 times higher than those of termites. Eavesdropping on passive walking signals explains the predator detection and foraging behaviours in this ancient relationship, which may be applicable to many other predator-prey relationships. © 2017 John Wiley & Sons Ltd/CNRS.

  17. The exploitation of an ant-defended host plant by a shelter-building herbivore.

    PubMed

    Eubanks, Micky D; Nesci, Kimberly A; Petersen, Mette K; Liu, Zhiwei; Sanchez, Horacio Bonfil

    1997-02-01

    Larvae of a Polyhymno species (Lepidoptera: Gelechiidae) feed on the ant-defended acacia, Acacia cornigera, in the tropical lowlands of Veracruz, Mexico. Polyhymno larvae construct sealed shelters by silking together the pinna or pinnules of acacia leaves. Although larval density and larval survival are higher on acacias not occupied by ants, shelters serve as a partial refuge from the ant Pseudomyrmex ferruginea (Hymenoptera: Formicidae), which defends A. cornigera plants; thus, shelters provide Polyhymno larvae access to an ant-defended host plant. P. ferruginea ants act as the primary antiherbivore defense of A. cornigera plants, which lack the chemical and mechanical defenses of non-ant-defended acacias. Thus, defeating the ant defense of A. cornigera provides Polyhymno larvae access to an otherwise poorly defended host plant. Damage caused by Polyhymno larval feeding reaches levels which can kill A. cornigera plants.

  18. Harvester ant bioassay for assessing hazardous chemical waste sites. [Pogonomyrmex owhyeei

    SciTech Connect

    Gano, K.A.; Carlile, D.W.; Rogers, L.E.

    1985-05-01

    A technique was developed for using harvester ants, Pogonomyrmex owhyeei, in terrestrial bioassays. Procedures were developed for maintaining stock populations, handling ants, and exposing ants to toxic materials. Relative toxicities were determined by exposing ants to 10 different materials. These materials included three insecticides, Endrin, Aldrin, and Dieldrin; one herbicide, 2,4-D; three complex industrial waste residuals, wood preservative sludge, drilling fluid, and slop oil; and three heavy metals, copper zinc, and cadium. Ants were exposed in petri dishes containing soil amended with a particular toxicant. Under these test conditions, ants showed no sensitivity to the metals or 2,4-D. Ants weremore » sensitive to the insecticides and oils in repeated tests, and relative toxicity remained consistent throughout. Aldrin was the most toxic material followed by Dieldrin, Endrin, wood preservative sludge, drilling fluid, and slop oil. 12 refs., 2 figs., 2 tabs.« less

  19. Rarity and diversity in forest ant assemblages of Great Smoky Mountains National Park

    USGS Publications Warehouse

    Lessard, J.-P.; Dunn, R.R.; Parker, C.R.; Sanders, N.J.

    2007-01-01

    We report on a systematic survey of the ant fauna occurring in hardwood forests in the Great Smoky Mountains National Park. At 22-mixed hardwood sites, we collected leaf-litter ant species using Winkler samplers. At eight of those sites, we also collected ants using pitfall and Malaise traps. In total, we collected 53 ant species. As shown in other studies, ant species richness tended to decline with increasing elevation. Leaf-litter ant assemblages were also highly nested. Several common species were both locally abundant and had broad distributions, while many other species were rarely detected. Winkler samplers, pitfall traps, and Malaise traps yielded samples that differed in composition, but not richness, from one another. Taken together, our work begins to illuminate the factors that govern the diversity, distribution, abundance, and perhaps rarity of ants of forested ecosystems in the Great Smoky Mountains National Park.

  20. Temporal Variation in the Abundance and Richness of Foliage-Dwelling Ants Mediated by Extrafloral Nectar.

    PubMed

    Belchior, Ceres; Sendoya, Sebastián F; Del-Claro, Kleber

    2016-01-01

    Plants bearing extrafloral nectaries (EFNs) are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1) EFN-bearing plants are more visited by ants than EFN-lacking plants; 2) ant visitation is higher in the rainy season than in dry season; 3) plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4) during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5) the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m2), in the rainy (October-January) and dry seasons (April-July) of 2010-2011. Plants (72 species; 762 individuals) were checked three times per season for ant presence. Results showed that 21 species (29%) and 266 individuals (35%) possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season). In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation.

  1. Urban habitat complexity affects species richness but not environmental filtering of morphologically-diverse ants

    PubMed Central

    Nash, Michael A.; Christie, Fiona J.; Hahs, Amy K.; Livesley, Stephen J.

    2015-01-01

    Habitat complexity is a major determinant of structure and diversity of ant assemblages. Following the size-grain hypothesis, smaller ant species are likely to be advantaged in more complex habitats compared to larger species. Habitat complexity can act as an environmental filter based on species size and morphological traits, therefore affecting the overall structure and diversity of ant assemblages. In natural and semi-natural ecosystems, habitat complexity is principally regulated by ecological successions or disturbance such as fire and grazing. Urban ecosystems provide an opportunity to test relationships between habitat, ant assemblage structure and ant traits using novel combinations of habitat complexity generated and sustained by human management. We sampled ant assemblages in low-complexity and high-complexity parks, and high-complexity woodland remnants, hypothesizing that (i) ant abundance and species richness would be higher in high-complexity urban habitats, (ii) ant assemblages would differ between low- and high-complexity habitats and (iii) ants living in high-complexity habitats would be smaller than those living in low-complexity habitats. Contrary to our hypothesis, ant species richness was higher in low-complexity habitats compared to high-complexity habitats. Overall, ant assemblages were significantly different among the habitat complexity types investigated, although ant size and morphology remained the same. Habitat complexity appears to affect the structure of ant assemblages in urban ecosystems as previously observed in natural and semi-natural ecosystems. However, the habitat complexity filter does not seem to be linked to ant morphological traits related to body size. PMID:26528416

  2. Temporal Variation in the Abundance and Richness of Foliage-Dwelling Ants Mediated by Extrafloral Nectar

    PubMed Central

    Belchior, Ceres; Sendoya, Sebastián F.

    2016-01-01

    Plants bearing extrafloral nectaries (EFNs) are common in the Brazilian cerrado savanna, where climatic conditions having marked seasonality influence arboreal ant fauna organization. These ant-plant interactions have rarely been studied at community level. Here, we tested whether: 1) EFN-bearing plants are more visited by ants than EFN-lacking plants; 2) ant visitation is higher in the rainy season than in dry season; 3) plants producing young leaves are more visited than those lacking young leaves in the rainy season; 4) during the dry season, plants with old leaves and flowers are more visited than plants with young leaves and bare of leaves or flowers; 5) the composition of visiting ant fauna differs between plants with and without EFNs. Field work was done in a cerrado reserve near Uberlândia, MG State, Brazil, along ten transects (total area 3,000 m2), in the rainy (October-January) and dry seasons (April-July) of 2010–2011. Plants (72 species; 762 individuals) were checked three times per season for ant presence. Results showed that 21 species (29%) and 266 individuals (35%) possessed EFNs. These plants attracted 38 ant species (36 in rainy, 26 in dry season). In the rainy season, plants with EFNs had higher ant abundance/richness than plants without EFNs, but in the dry season, EFN presence did not influence ant visitation. Plant phenology affected ant richness and abundance in different ways: plants with young leaves possessed higher ant richness in the rainy season, but in the dry season ant abundance was higher on plants possessing old leaves or flowers. The species composition of plant-associated ant communities, however, did not differ between plants with and without EFNs in either season. These findings suggest that the effect of EFN presence on a community of plant-visiting ants is context dependent, being conditioned to seasonal variation. PMID:27438722

  3. Influences of Species Interactions With Aggressive Ants and Habitat Filtering on Nest Colonization and Community Composition of Arboreal Twig-Nesting Ants.

    PubMed

    Philpott, Stacy M; Serber, Zachary; De la Mora, Aldo

    2018-04-05

    Ant community assembly is driven by many factors including species interactions (e.g., competition, predation, parasitism), habitat filtering (e.g., vegetation differences, microclimate, food and nesting resources), and dispersal. Canopy ant communities, including dominant and twig-nesting ants, are structured by all these different factors, but we know less about the impacts of species interactions and habitat filters acting at the colonization or recruitment stage. We examined occupation of artificial twig nests placed in shade trees in coffee agroecosystems. We asked whether species interactions-aggression from the dominant canopy ant, Azteca sericeasur Longino (Hymenoptera: Formicidae)-or habitat filtering-species of tree where nests were placed or surrounding vegetation-influence colonization, species richness, and community composition of twig-nesting ants. We found 20 species of ants occupying artificial nests. Nest occupation was lower on trees with A. sericeasur, but did not differ depending on tree species or surrounding vegetation. Yet, there were species-specific differences in occupation depending on A. sericeasur presence and tree species. Ant species richness did not vary with A. sericeasur presence or tree species. Community composition varied with A. sericeasur presence and surrounding vegetation. Our results suggest that species interactions with dominant ants are important determinants of colonization and community composition of twig-nesting ants. Habitat filtering at the level of tree species did not have strong effects on twig-nesting ants, but changes in coffee management may contribute to differences in community composition with important implications for ant conservation in agricultural landscapes, as well as biological control of coffee pests.

  4. Arboreal Ant Colonies as ‘Hot-Points’ of Cryptic Diversity for Myrmecophiles: The Weaver Ant Camponotus sp. aff. textor and Its Interaction Network with Its Associates

    PubMed Central

    Pérez-Lachaud, Gabriela; Lachaud, Jean-Paul

    2014-01-01

    Introduction Systematic surveys of macrofaunal diversity within ant colonies are lacking, particularly for ants nesting in microhabitats that are difficult to sample. Species associated with ants are generally small and rarely collected organisms, which makes them more likely to be unnoticed. We assumed that this tendency is greater for arthropod communities in microhabitats with low accessibility, such as those found in the nests of arboreal ants that may constitute a source of cryptic biodiversity. Materials and Methods We investigated the invertebrate diversity associated with an undescribed, but already threatened, Neotropical Camponotus weaver ant. As most of the common sampling methods used in studies of ant diversity are not suited for evaluating myrmecophile diversity within ant nests, we evaluated the macrofauna within ant nests through exhaustive colony sampling of three nests and examination of more than 80,000 individuals. Results We identified invertebrates from three classes belonging to 18 taxa, some of which were new to science, and recorded the first instance of the co-occurrence of two brood parasitoid wasp families attacking the same ant host colony. This diversity of ant associates corresponded to a highly complex interaction network. Agonistic interactions prevailed, but the prevalence of myrmecophiles was remarkably low. Conclusions Our data support the hypothesis of the evolution of low virulence in a variety of symbionts associated with large insect societies. Because most myrmecophiles found in this work are rare, strictly specific, and exhibit highly specialized biology, the risk of extinction for these hitherto unknown invertebrates and their natural enemies is high. The cryptic, far unappreciated diversity within arboreal ant nests in areas at high risk of habitat loss qualifies these nests as ‘hot-points’ of biodiversity that urgently require special attention as a component of conservation and management programs. PMID:24941047

  5. Arboreal ant colonies as 'hot-points' of cryptic diversity for myrmecophiles: the weaver ant Camponotus sp. aff. textor and its interaction network with its associates.

    PubMed

    Pérez-Lachaud, Gabriela; Lachaud, Jean-Paul

    2014-01-01

    Systematic surveys of macrofaunal diversity within ant colonies are lacking, particularly for ants nesting in microhabitats that are difficult to sample. Species associated with ants are generally small and rarely collected organisms, which makes them more likely to be unnoticed. We assumed that this tendency is greater for arthropod communities in microhabitats with low accessibility, such as those found in the nests of arboreal ants that may constitute a source of cryptic biodiversity. We investigated the invertebrate diversity associated with an undescribed, but already threatened, Neotropical Camponotus weaver ant. As most of the common sampling methods used in studies of ant diversity are not suited for evaluating myrmecophile diversity within ant nests, we evaluated the macrofauna within ant nests through exhaustive colony sampling of three nests and examination of more than 80,000 individuals. We identified invertebrates from three classes belonging to 18 taxa, some of which were new to science, and recorded the first instance of the co-occurrence of two brood parasitoid wasp families attacking the same ant host colony. This diversity of ant associates corresponded to a highly complex interaction network. Agonistic interactions prevailed, but the prevalence of myrmecophiles was remarkably low. Our data support the hypothesis of the evolution of low virulence in a variety of symbionts associated with large insect societies. Because most myrmecophiles found in this work are rare, strictly specific, and exhibit highly specialized biology, the risk of extinction for these hitherto unknown invertebrates and their natural enemies is high. The cryptic, far unappreciated diversity within arboreal ant nests in areas at high risk of habitat loss qualifies these nests as 'hot-points' of biodiversity that urgently require special attention as a component of conservation and management programs.

  6. Study on bi-directional pedestrian movement using ant algorithms

    NASA Astrophysics Data System (ADS)

    Sibel, Gokce; Ozhan, Kayacan

    2016-01-01

    A cellular automata model is proposed to simulate bi-directional pedestrian flow. Pedestrian movement is investigated by using ant algorithms. Ants communicate with each other by dropping a chemical, called a pheromone, on the substrate while crawling forward. Similarly, it is considered that oppositely moving pedestrians drop ‘visual pheromones’ on their way and the visual pheromones might cause attractive or repulsive interactions. This pheromenon is introduced into modelling the pedestrians’ walking preference. In this way, the decision-making process of pedestrians will be based on ‘the instinct of following’. At some densities, the relationships of velocity-density and flux-density are analyzed for different evaporation rates of visual pheromones. Lane formation and phase transition are observed for certain evaporation rates of visual pheromones.

  7. Response Ant Colony Optimization of End Milling Surface Roughness

    PubMed Central

    Kadirgama, K.; Noor, M. M.; Abd Alla, Ahmed N.

    2010-01-01

    Metal cutting processes are important due to increased consumer demands for quality metal cutting related products (more precise tolerances and better product surface roughness) that has driven the metal cutting industry to continuously improve quality control of metal cutting processes. This paper presents optimum surface roughness by using milling mould aluminium alloys (AA6061-T6) with Response Ant Colony Optimization (RACO). The approach is based on Response Surface Method (RSM) and Ant Colony Optimization (ACO). The main objectives to find the optimized parameters and the most dominant variables (cutting speed, feedrate, axial depth and radial depth). The first order model indicates that the feedrate is the most significant factor affecting surface roughness. PMID:22294914

  8. How many gamergates is an ant queen worth?

    NASA Astrophysics Data System (ADS)

    Monnin, Thibaud; Peeters, Christian

    2008-02-01

    Ant reproductives exhibit different morphological adaptations linked to dispersal and fertility. By reviewing the literature on taxa where workers can reproduce sexually (i.e. become gamergates) we show that (1) species with a single gamergate generally have lost the winged queen caste, whereas only half of the species with several gamergates have, and (2) single-gamergate species have smaller colonies than multiple-gamergate species. Comparison with “classical” ants without gamergates, where having one vs having several winged queens are two distinct syndromes, suggests that having one vs having several gamergates are not. Gamergate number does not affect the success of colony fission, but retention of the queen caste permits the option of independent foundation.

  9. Young fire ant workers feign death and survive aggressive neighbors

    NASA Astrophysics Data System (ADS)

    Cassill, Deby L.; Vo, Kim; Becker, Brandie

    2008-07-01

    Feigning death is a method of self-defense employed among a wide range of prey species when threatened by predator species. This paper reports on death-feigning behavior by the fire ant, Solenopsis invicta, during intraspecific aggression among neighboring fire ant workers. Days-old workers responded to aggression by death feigning, weeks-old workers responded by fleeing and months-old workers responded by fighting back. By feigning death, days-old workers were four times more likely to survive aggression than older workers. From a proximate perspective, retaliation by young workers against aggressive older workers is certain to fail. With their relatively soft exoskeleton, young workers would be prone to injury and death and unable to execute an effective attack of biting or stinging older workers with harder exoskeletons. From an ultimate perspective, death feigning allows young workers to survive and contribute to brood care and colony growth, both of which are essential to queen survival and fitness.

  10. Ants and termites increase crop yield in a dry climate.

    PubMed

    Evans, Theodore A; Dawes, Tracy Z; Ward, Philip R; Lo, Nathan

    2011-03-29

    Agricultural intensification has increased crop yields, but at high economic and environmental cost. Harnessing ecosystem services of naturally occurring organisms is a cheaper but under-appreciated approach, because the functional roles of organisms are not linked to crop yields, especially outside the northern temperate zone. Ecosystem services in soil come from earthworms in these cooler and wetter latitudes; what may fulfill their functional role in agriculture in warmer and drier habitats, where they are absent, is unproven. Here we show in a field experiment that ants and termites increase wheat yield by 36% from increased soil water infiltration due to their tunnels and improved soil nitrogen. Our results suggest that ants and termites have similar functional roles to earthworms, and that they may provide valuable ecosystem services in dryland agriculture, which may become increasingly important for agricultural sustainability in arid climates.

  11. Ants and termites increase crop yield in a dry climate

    PubMed Central

    Evans, Theodore A.; Dawes, Tracy Z.; Ward, Philip R.; Lo, Nathan

    2011-01-01

    Agricultural intensification has increased crop yields, but at high economic and environmental cost. Harnessing ecosystem services of naturally occurring organisms is a cheaper but under-appreciated approach, because the functional roles of organisms are not linked to crop yields, especially outside the northern temperate zone. Ecosystem services in soil come from earthworms in these cooler and wetter latitudes; what may fulfill their functional role in agriculture in warmer and drier habitats, where they are absent, is unproven. Here we show in a field experiment that ants and termites increase wheat yield by 36% from increased soil water infiltration due to their tunnels and improved soil nitrogen. Our results suggest that ants and termites have similar functional roles to earthworms, and that they may provide valuable ecosystem services in dryland agriculture, which may become increasingly important for agricultural sustainability in arid climates. PMID:21448161

  12. Annealing Ant Colony Optimization with Mutation Operator for Solving TSP

    PubMed Central

    2016-01-01

    Ant Colony Optimization (ACO) has been successfully applied to solve a wide range of combinatorial optimization problems such as minimum spanning tree, traveling salesman problem, and quadratic assignment problem. Basic ACO has drawbacks of trapping into local minimum and low convergence rate. Simulated annealing (SA) and mutation operator have the jumping ability and global convergence; and local search has the ability to speed up the convergence. Therefore, this paper proposed a hybrid ACO algorithm integrating the advantages of ACO, SA, mutation operator, and local search procedure to solve the traveling salesman problem. The core of algorithm is based on the ACO. SA and mutation operator were used to increase the ants population diversity from time to time and the local search was used to exploit the current search area efficiently. The comparative experiments, using 24 TSP instances from TSPLIB, show that the proposed algorithm outperformed some well-known algorithms in the literature in terms of solution quality. PMID:27999590

  13. Annealing Ant Colony Optimization with Mutation Operator for Solving TSP.

    PubMed

    Mohsen, Abdulqader M

    2016-01-01

    Ant Colony Optimization (ACO) has been successfully applied to solve a wide range of combinatorial optimization problems such as minimum spanning tree, traveling salesman problem, and quadratic assignment problem. Basic ACO has drawbacks of trapping into local minimum and low convergence rate. Simulated annealing (SA) and mutation operator have the jumping ability and global convergence; and local search has the ability to speed up the convergence. Therefore, this paper proposed a hybrid ACO algorithm integrating the advantages of ACO, SA, mutation operator, and local search procedure to solve the traveling salesman problem. The core of algorithm is based on the ACO. SA and mutation operator were used to increase the ants population diversity from time to time and the local search was used to exploit the current search area efficiently. The comparative experiments, using 24 TSP instances from TSPLIB, show that the proposed algorithm outperformed some well-known algorithms in the literature in terms of solution quality.

  14. Ants' learning of nest entrance characteristics (Hymenoptera, Formicidae).

    PubMed

    Cammaerts, M C

    2014-02-01

    Young workers, experimentally removed from their nest and set in front of it, are not very good at finding the nest entrance and entering the nest. I examined how young ants learn their nest entrance characteristics, dealing only with the entrance sensu stricto, not with its vicinity. I observed that young ants have the innate behavior of trying to exit and re-enter their nest. I found that they are imprinted with the nest entrance odor while they are still living inside their nest and that they learn the visual aspect of their nest entrances, thanks to operant conditioning, when they exit their nest and succeed in re-entering in the course of their first short trips outside.

  15. How lost "passenger" ants find their way home.

    PubMed

    Srinivasan, Mandyam V

    2018-03-01

    Animal navigation has fascinated biologists and engineers for centuries, and some of the most illuminating discoveries have come from the study of creatures with a brain no larger than a sesame seed. In an elegant recent study, Pfeiffer and Wittlinger (Science, 353, 1155-1157, 2016) have shown the means by which desert ants, carried from one nest to another by a relative, find their own way back home if they are accidentally dropped en route.

  16. Dynamic optimization of chemical processes using ant colony framework.

    PubMed

    Rajesh, J; Gupta, K; Kusumakar, H S; Jayaraman, V K; Kulkarni, B D

    2001-11-01

    Ant colony framework is illustrated by considering dynamic optimization of six important bench marking examples. This new computational tool is simple to implement and can tackle problems with state as well as terminal constraints in a straightforward fashion. It requires fewer grid points to reach the global optimum at relatively very low computational effort. The examples with varying degree of complexities, analyzed here, illustrate its potential for solving a large class of process optimization problems in chemical engineering.

  17. ANTS/PAM: Future Exploration of the Asteroid Belt

    NASA Astrophysics Data System (ADS)

    Clark, P. E.; Curtis, S. A.; Rilee, M. L.; Cheung, C. Y.

    2004-05-01

    The Autonomous Nano-Technology Swarm (ANTS) is applied to the Prospecting Asteroid Mission (PAM) concept, as part of a NASA RASC study. The ANTS architecture is inspired by success of social insect colonies, based on the division of labor within the colonies: 1) within their specialties, individual specialists generally outperform general-ists, and 2) with sufficiently efficient social interaction and coordination, the group of specialists generally outper-forms the group of generalists. ANTS as applied to PAM involves a thousand individual specialist `sciencecraft', one subswarm per target, in an environment where detection and tracking of irregular, infrequent targets is a major chal-lenge. Workers, carry and operate eight to nine different scientific instruments, including spectrometers, ranging and radio science devices, imagers. The remaining specialists, Messenger/Rulers, provide communication and coordina-tion. The non-expendable propulsion system is based on autonomously deployable and configurable solar sails, a system suitable to a low gravity environment. The design of the neural basis function requires a minimum of 4 or 5 specialists for collective decision making. Allowing for ten instrument specialist teams and compensating for antici-pated high attrition, we calculate an initial minimum of 100 per subswarm should allow characterization of hundreds of asteroids. The difficulty in observing irregular, rapidly moving, poorly illuminated objects is largely overcome by the ANT sciencecraft capability to optimize conditions for each instrument. Components are composed of carbon nanotubules reversibly deployable from NEMS nodes, allowing 100 times decrease in packaging volume. 1000 smart 10 centimeter, 1 kg cubic boxes create a 1000 kg 1 meter cube.

  18. Petrology of 60035 - Evolution of a polymict ANT breccia

    NASA Technical Reports Server (NTRS)

    Warner, R. D.; Taylor, G. J.; Keil, K.

    1980-01-01

    Extensive analysis of the lunar rock sample 60035 with optical microscopy and electron microprobe methods show it to be a polymict ANT breccia partly coated with glass, containing abundant clasts which have troctolitic/noritic anorthosite compositions. At least two episodes of crushing and mixing were involved in the petrogenesis of 60035, and annealing and mineral equilibration have not been extensive since the formation of the breccia.

  19. Dominance-diversity relationships in ant communities differ with invasion.

    PubMed

    Arnan, Xavier; Andersen, Alan N; Gibb, Heloise; Parr, Catherine L; Sanders, Nathan J; Dunn, Robert R; Angulo, Elena; Baccaro, Fabricio B; Bishop, Tom R; Boulay, Raphaël; Castracani, Cristina; Cerdá, Xim; Toro, Israel Del; Delsinne, Thibaut; Donoso, David A; Elten, Emilie K; Fayle, Tom M; Fitzpatrick, Matthew C; Gómez, Crisanto; Grasso, Donato A; Grossman, Blair F; Guénard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin D; Janda, Milan; Jenkins, Clinton N; Klimes, Petr; Lach, Lori; Laeger, Thomas; Leponce, Maurice; Lucky, Andrea; Majer, Jonathan; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Paknia, Omid; Pfeiffer, Martin; Philpott, Stacy M; Souza, Jorge L P; Tista, Melanie; Vasconcelos, Heraldo L; Retana, Javier

    2018-05-30

    The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance-impoverishment rule states that high levels of dominance only occur in species-poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non-native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground-dwelling ants distributed across five continents to document the generality of the dominance-impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance-diversity relationship varies greatly, and depends on whether dominant species are native or non-native, whether dominance is considered as occurrence or relative abundance, and on variation in mean annual temperature. There were declines in diversity with increasing dominance in invaded communities, but diversity increased with increasing dominance in native communities. These patterns occur along the global temperature gradient. However, positive and negative relationships are strongest in the hottest sites. We also found that climate regulates the degree of behavioral dominance, but differently from how it shapes species richness. Our findings imply that, despite strong competitive interactions among ants, competitive exclusion is not a major driver of local richness in native ant communities. Although the dominance-impoverishment rule applies to invaded communities, we propose an alternative dominance-diversification rule for native communities. © 2018 John Wiley & Sons Ltd.

  20. Contrasting species and functional beta diversity in montane ant assemblages.

    PubMed

    Bishop, Tom R; Robertson, Mark P; van Rensburg, Berndt J; Parr, Catherine L

    2015-09-01

    Beta diversity describes the variation in species composition between sites and can be used to infer why different species occupy different parts of the globe. It can be viewed in a number of ways. First, it can be partitioned into two distinct patterns: turnover and nestedness. Second, it can be investigated from either a species identity or a functional-trait point of view. We aim to document for the first time how these two aspects of beta diversity vary in response to a large environmental gradient. Maloti-Drakensberg Mountains, southern Africa. We sampled ant assemblages along an extensive elevational gradient (900-3000 m a.s.l.) twice yearly for 7 years, and collected functional-trait information related to the species' dietary and habitat-structure preferences. We used recently developed methods to partition species and functional beta diversity into their turnover and nestedness components. A series of null models were used to test whether the observed beta diversity patterns differed from random expectations. Species beta diversity was driven by turnover, but functional beta diversity was composed of both turnover and nestedness patterns at different parts of the gradient. Null models revealed that deterministic processes were likely to be responsible for the species patterns but that the functional changes were indistinguishable from stochasticity. Different ant species are found with increasing elevation, but they tend to represent an increasingly nested subset of the available functional strategies. This finding is unique and narrows down the list of possible factors that control ant existence across elevation. We conclude that diet and habitat preferences have little role in structuring ant assemblages in montane environments and that some other factor must be driving the non-random patterns of species turnover. This finding also highlights the importance of distinguishing between different kinds of beta diversity.

  1. Emergent oscillations assist obstacle negotiation during ant cooperative transport.

    PubMed

    Gelblum, Aviram; Pinkoviezky, Itai; Fonio, Ehud; Gov, Nir S; Feinerman, Ofer

    2016-12-20

    Collective motion by animal groups is affected by internal interactions, external constraints, and the influx of information. A quantitative understanding of how these different factors give rise to different modes of collective motion is, at present, lacking. Here, we study how ants that cooperatively transport a large food item react to an obstacle blocking their path. Combining experiments with a statistical physics model of mechanically coupled active agents, we show that the constraint induces a deterministic collective oscillatory mode that facilitates obstacle circumvention. We provide direct experimental evidence, backed by theory, that this motion is an emergent group effect that does not require any behavioral changes at the individual level. We trace these relaxation oscillations to the interplay between two forces; informed ants pull the load toward the nest whereas uninformed ants contribute to the motion's persistence along the tangential direction. The model's predictions that oscillations appear above a critical system size, that the group can spontaneously transition into its ordered phase, and that the system can exhibit complete rotations are all verified experimentally. We expect that similar oscillatory modes emerge in collective motion scenarios where the structure of the environment imposes conflicts between individually held information and the group's tendency for cohesiveness.

  2. Draft genome of the red harvester ant Pogonomyrmex barbatus.

    PubMed

    Smith, Chris R; Smith, Christopher D; Robertson, Hugh M; Helmkampf, Martin; Zimin, Aleksey; Yandell, Mark; Holt, Carson; Hu, Hao; Abouheif, Ehab; Benton, Richard; Cash, Elizabeth; Croset, Vincent; Currie, Cameron R; Elhaik, Eran; Elsik, Christine G; Favé, Marie-Julie; Fernandes, Vilaiwan; Gibson, Joshua D; Graur, Dan; Gronenberg, Wulfila; Grubbs, Kirk J; Hagen, Darren E; Viniegra, Ana Sofia Ibarraran; Johnson, Brian R; Johnson, Reed M; Khila, Abderrahman; Kim, Jay W; Mathis, Kaitlyn A; Munoz-Torres, Monica C; Murphy, Marguerite C; Mustard, Julie A; Nakamura, Rin; Niehuis, Oliver; Nigam, Surabhi; Overson, Rick P; Placek, Jennifer E; Rajakumar, Rajendhran; Reese, Justin T; Suen, Garret; Tao, Shu; Torres, Candice W; Tsutsui, Neil D; Viljakainen, Lumi; Wolschin, Florian; Gadau, Jürgen

    2011-04-05

    We report the draft genome sequence of the red harvester ant, Pogonomyrmex barbatus. The genome was sequenced using 454 pyrosequencing, and the current assembly and annotation were completed in less than 1 y. Analyses of conserved gene groups (more than 1,200 manually annotated genes to date) suggest a high-quality assembly and annotation comparable to recently sequenced insect genomes using Sanger sequencing. The red harvester ant is a model for studying reproductive division of labor, phenotypic plasticity, and sociogenomics. Although the genome of P. barbatus is similar to other sequenced hymenopterans (Apis mellifera and Nasonia vitripennis) in GC content and compositional organization, and possesses a complete CpG methylation toolkit, its predicted genomic CpG content differs markedly from the other hymenopterans. Gene networks involved in generating key differences between the queen and worker castes (e.g., wings and ovaries) show signatures of increased methylation and suggest that ants and bees may have independently co-opted the same gene regulatory mechanisms for reproductive division of labor. Gene family expansions (e.g., 344 functional odorant receptors) and pseudogene accumulation in chemoreception and P450 genes compared with A. mellifera and N. vitripennis are consistent with major life-history changes during the adaptive radiation of Pogonomyrmex spp., perhaps in parallel with the development of the North American deserts.

  3. Bioturbation by the Fungus-Gardening Ant, Trachymyrmex septentrionalis

    PubMed Central

    Tschinkel, Walter R.; Seal, Jon N.

    2016-01-01

    Soil invertebrates such as ants are thought to be important manipulators of soils in temperate and tropical ecosystems. The fungus gardening ant, Trachymyrmex septentrionalis, is an important agent of biomantling, that is, of depositing soil excavated from below onto the surface, and has been suggested as an agent of bioturbation (moving soil below ground) as well. The amount of bioturbation by this ant was quantified by planting queenright colonies in sand columns consisting of 5 layers of different colored sand. The amount of each color of sand deposited on the surface was determined from April to November 2015. In November, colonies were excavated and the color and amount of sand deposited below ground (mostly as backfill in chambers) was determined. Extrapolated to one ha, T. septentrionalis deposited 800 kg of sand per annum on the surface, and an additional 200 kg (17% of the total excavated) below ground. On average, this mixes 1.3% of the sand from other layers within the top meter of soil per millennium, but this mixing is unlikely to be homogeneous, and probably occurs as "hotspots" in both horizontal and vertical space. Such mixing is discussed as a challenge to sediment dating by optically stimulated luminescence (OSL). PMID:27391485

  4. Using Ant Colony Optimization for Routing in VLSI Chips

    NASA Astrophysics Data System (ADS)

    Arora, Tamanna; Moses, Melanie

    2009-04-01

    Rapid advances in VLSI technology have increased the number of transistors that fit on a single chip to about two billion. A frequent problem in the design of such high performance and high density VLSI layouts is that of routing wires that connect such large numbers of components. Most wire-routing problems are computationally hard. The quality of any routing algorithm is judged by the extent to which it satisfies routing constraints and design objectives. Some of the broader design objectives include minimizing total routed wire length, and minimizing total capacitance induced in the chip, both of which serve to minimize power consumed by the chip. Ant Colony Optimization algorithms (ACO) provide a multi-agent framework for combinatorial optimization by combining memory, stochastic decision and strategies of collective and distributed learning by ant-like agents. This paper applies ACO to the NP-hard problem of finding optimal routes for interconnect routing on VLSI chips. The constraints on interconnect routing are used by ants as heuristics which guide their search process. We found that ACO algorithms were able to successfully incorporate multiple constraints and route interconnects on suite of benchmark chips. On an average, the algorithm routed with total wire length 5.5% less than other established routing algorithms.

  5. Ante mortem identification of BSE from serum using infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Schmitt, Jürgen; Lasch, Peter; Beekes, Michael; Udelhoven, Thomas; Eiden, Michael; Fabian, Heinz; Petrich, Wolfgang H.; Naumann, Dieter

    2004-07-01

    In our former studies a diagnostic approach for the detection of transmissible spongiform encephalopaties (TSE) based on FT-IR spectroscopy in combination with artificial neural networks was described, based on a controlled animal study with terminally ill Syrian hamsters and control animals. As a consequence of the bovine spongiform encephalopathy (BSE) crisis in Europe, the development of a disgnostic ante mortem test for cattle has become a matter of great scientific importance and public interest. Since 1986 more than 180,000 clinical cases of BSE have been observed in the UK alone. Most of these cases were confirmed by post mortem examination of brain tissue. However, BSE-related risk assessment and risk-management would greatly benefit from ante mortem testing on living animals. For example, a serum-based test could allow for screening of the cattle population, thus, even a BSE eradication program would be conceivable. Here we report on a novel method for ante mortem BSE testing, which combines infrared spectroscopy of serum samples with multivariate pattern recognition analysis. A classification algorithm was trained using infrared spectra of sera from more than 800 animals from a field study (including BSE positive, healthy controls and animals suffering from viral or bacterial infections). In two validation studies sensitivities of 85% and 87% and specificities of 84% and 91% were achieved, respectively. The combination of classification algorithms increased sensitivity and specificity to 96% and 92%, respectively.

  6. A seismic fault recognition method based on ant colony optimization

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Xiao, Chuangbai; Li, Xueliang; Wang, Zhenli; Huo, Shoudong

    2018-05-01

    Fault recognition is an important section in seismic interpretation and there are many methods for this technology, but no one can recognize fault exactly enough. For this problem, we proposed a new fault recognition method based on ant colony optimization which can locate fault precisely and extract fault from the seismic section. Firstly, seismic horizons are extracted by the connected component labeling algorithm; secondly, the fault location are decided according to the horizontal endpoints of each horizon; thirdly, the whole seismic section is divided into several rectangular blocks and the top and bottom endpoints of each rectangular block are considered as the nest and food respectively for the ant colony optimization algorithm. Besides that, the positive section is taken as an actual three dimensional terrain by using the seismic amplitude as a height. After that, the optimal route from nest to food calculated by the ant colony in each block is judged as a fault. Finally, extensive comparative tests were performed on the real seismic data. Availability and advancement of the proposed method were validated by the experimental results.

  7. Rescue of newborn ants by older Cataglyphis cursor adult workers.

    PubMed

    Nowbahari, Elise; Amirault, Céline; Hollis, Karen L

    2016-05-01

    Cataglyphis cursor worker ants are capable of highly sophisticated rescue behaviour in which individuals are able to identify what has trapped a nestmate and to direct their behaviour towards that obstacle. Nonetheless, rescue behaviour is constrained by workers' subcaste: whereas foragers, the oldest workers, are able both to give and to receive the most help, the youngest workers, inactives, neither give nor receive any help whatsoever; nurses give and receive intermediate levels of aid, reflecting their intermediate age. Such differences in rescue behaviour across subcastes suggest that age and experience play a critical role. In this species, as in many others in which a sensitive period for nestmate recognition exists, newly enclosed ants, called callows, are adopted by ants belonging not only to different colonies but also to different species; foreign callows receive nearly the same special care provided to resident newborns. Because callows are younger than inactives, which are incapable of soliciting rescue, we wondered whether entrapped callows would receive such aid. In the present study, we artificially ensnared individual callows from their own colony (homocolonial), from a different colony (heterocolonial), and from a different species (heterospecific), and tested each one with groups of five potential C. cursor rescuers, either all foragers or all nurses. Our results show that all three types of callows are able to elicit rescue behaviour from both foragers and nurses. Nonetheless, nurse rescuers are better able to discriminate between the three types of callow victims than are foragers.

  8. Ant system: optimization by a colony of cooperating agents.

    PubMed

    Dorigo, M; Maniezzo, V; Colorni, A

    1996-01-01

    An analogy with the way ant colonies function has suggested the definition of a new computational paradigm, which we call ant system (AS). We propose it as a viable new approach to stochastic combinatorial optimization. The main characteristics of this model are positive feedback, distributed computation, and the use of a constructive greedy heuristic. Positive feedback accounts for rapid discovery of good solutions, distributed computation avoids premature convergence, and the greedy heuristic helps find acceptable solutions in the early stages of the search process. We apply the proposed methodology to the classical traveling salesman problem (TSP), and report simulation results. We also discuss parameter selection and the early setups of the model, and compare it with tabu search and simulated annealing using TSP. To demonstrate the robustness of the approach, we show how the ant system (AS) can be applied to other optimization problems like the asymmetric traveling salesman, the quadratic assignment and the job-shop scheduling. Finally we discuss the salient characteristics-global data structure revision, distributed communication and probabilistic transitions of the AS.

  9. Identification of an ant queen pheromone regulating worker sterility.

    PubMed

    Holman, Luke; Jørgensen, Charlotte G; Nielsen, John; d'Ettorre, Patrizia

    2010-12-22

    The selective forces that shape and maintain eusocial societies are an enduring puzzle in evolutionary biology. Ordinarily sterile workers can usually reproduce given the right conditions, so the factors regulating reproductive division of labour may provide insight into why eusociality has persisted over evolutionary time. Queen-produced pheromones that affect worker reproduction have been implicated in diverse taxa, including ants, termites, wasps and possibly mole rats, but to date have only been definitively identified in the honeybee. Using the black garden ant Lasius niger, we isolate the first sterility-regulating ant queen pheromone. The pheromone is a cuticular hydrocarbon that comprises the majority of the chemical profile of queens and their eggs, and also affects worker behaviour, by reducing aggression towards objects bearing the pheromone. We further show that the pheromone elicits a strong response in worker antennae and that its production by queens is selectively reduced following an immune challenge. These results suggest that the pheromone has a central role in colony organization and support the hypothesis that worker sterility represents altruistic self-restraint in response to an honest quality signal.

  10. Ant Navigation: Fractional Use of the Home Vector

    PubMed Central

    Cheung, Allen; Hiby, Lex; Narendra, Ajay

    2012-01-01

    Home is a special location for many animals, offering shelter from the elements, protection from predation, and a common place for gathering of the same species. Not surprisingly, many species have evolved efficient, robust homing strategies, which are used as part of each and every foraging journey. A basic strategy used by most animals is to take the shortest possible route home by accruing the net distances and directions travelled during foraging, a strategy well known as path integration. This strategy is part of the navigation toolbox of ants occupying different landscapes. However, when there is a visual discrepancy between test and training conditions, the distance travelled by animals relying on the path integrator varies dramatically between species: from 90% of the home vector to an absolute distance of only 50 cm. We here ask what the theoretically optimal balance between PI-driven and landmark-driven navigation should be. In combination with well-established results from optimal search theory, we show analytically that this fractional use of the home vector is an optimal homing strategy under a variety of circumstances. Assuming there is a familiar route that an ant recognizes, theoretically optimal search should always begin at some fraction of the home vector, depending on the region of familiarity. These results are shown to be largely independent of the search algorithm used. Ant species from different habitats appear to have optimized their navigation strategy based on the availability and nature of navigational information content in their environment. PMID:23209744

  11. Ants sow the seeds of global diversification in flowering plants.

    PubMed

    Lengyel, Szabolcs; Gove, Aaron D; Latimer, Andrew M; Majer, Jonathan D; Dunn, Robert R

    2009-01-01

    The extraordinary diversification of angiosperm plants in the Cretaceous and Tertiary periods has produced an estimated 250,000-300,000 living angiosperm species and has fundamentally altered terrestrial ecosystems. Interactions with animals as pollinators or seed dispersers have long been suspected as drivers of angiosperm diversification, yet empirical examples remain sparse or inconclusive. Seed dispersal by ants (myrmecochory) may drive diversification as it can reduce extinction by providing selective advantages to plants and can increase speciation by enhancing geographical isolation by extremely limited dispersal distances. Using the most comprehensive sister-group comparison to date, we tested the hypothesis that myrmecochory leads to higher diversification rates in angiosperm plants. As predicted, diversification rates were substantially higher in ant-dispersed plants than in their non-myrmecochorous relatives. Data from 101 angiosperm lineages in 241 genera from all continents except Antarctica revealed that ant-dispersed lineages contained on average more than twice as many species as did their non-myrmecochorous sister groups. Contrasts in species diversity between sister groups demonstrated that diversification rates did not depend on seed dispersal mode in the sister group and were higher in myrmecochorous lineages in most biogeographic regions. Myrmecochory, which has evolved independently at least 100 times in angiosperms and is estimated to be present in at least 77 families and 11 000 species, is a key evolutionary innovation and a globally important driver of plant diversity. Myrmecochory provides the best example to date for a consistent effect of any mutualism on large-scale diversification.

  12. Ant brood function as life preservers during floods.

    PubMed

    Purcell, Jessica; Avril, Amaury; Jaffuel, Geoffrey; Bates, Sarah; Chapuisat, Michel

    2014-01-01

    Social organisms can surmount many ecological challenges by working collectively. An impressive example of such collective behavior occurs when ants physically link together into floating 'rafts' to escape from flooded habitat. However, raft formation may represent a social dilemma, with some positions posing greater individual risks than others. Here, we investigate the position and function of different colony members, and the costs and benefits of this functional geometry in rafts of the floodplain-dwelling ant Formica selysi. By causing groups of ants to raft in the laboratory, we observe that workers are distributed throughout the raft, queens are always in the center, and 100% of brood items are placed on the base. Through a series of experiments, we show that workers and brood are extremely resistant to submersion. Both workers and brood exhibit high survival rates after they have rafted, suggesting that occupying the base of the raft is not as costly as expected. The placement of all brood on the base of one cohesive raft confers several benefits: it preserves colony integrity, takes advantage of brood buoyancy, and increases the proportion of workers that immediately recover after rafting.

  13. Ant Brood Function as Life Preservers during Floods

    PubMed Central

    Purcell, Jessica; Avril, Amaury; Jaffuel, Geoffrey; Bates, Sarah; Chapuisat, Michel

    2014-01-01

    Social organisms can surmount many ecological challenges by working collectively. An impressive example of such collective behavior occurs when ants physically link together into floating ‘rafts’ to escape from flooded habitat. However, raft formation may represent a social dilemma, with some positions posing greater individual risks than others. Here, we investigate the position and function of different colony members, and the costs and benefits of this functional geometry in rafts of the floodplain-dwelling ant Formica selysi. By causing groups of ants to raft in the laboratory, we observe that workers are distributed throughout the raft, queens are always in the center, and 100% of brood items are placed on the base. Through a series of experiments, we show that workers and brood are extremely resistant to submersion. Both workers and brood exhibit high survival rates after they have rafted, suggesting that occupying the base of the raft is not as costly as expected. The placement of all brood on the base of one cohesive raft confers several benefits: it preserves colony integrity, takes advantage of brood buoyancy, and increases the proportion of workers that immediately recover after rafting. PMID:24586600

  14. Emergent oscillations assist obstacle negotiation during ant cooperative transport

    PubMed Central

    Gelblum, Aviram; Pinkoviezky, Itai; Fonio, Ehud; Gov, Nir S.; Feinerman, Ofer

    2016-01-01

    Collective motion by animal groups is affected by internal interactions, external constraints, and the influx of information. A quantitative understanding of how these different factors give rise to different modes of collective motion is, at present, lacking. Here, we study how ants that cooperatively transport a large food item react to an obstacle blocking their path. Combining experiments with a statistical physics model of mechanically coupled active agents, we show that the constraint induces a deterministic collective oscillatory mode that facilitates obstacle circumvention. We provide direct experimental evidence, backed by theory, that this motion is an emergent group effect that does not require any behavioral changes at the individual level. We trace these relaxation oscillations to the interplay between two forces; informed ants pull the load toward the nest whereas uninformed ants contribute to the motion’s persistence along the tangential direction. The model’s predictions that oscillations appear above a critical system size, that the group can spontaneously transition into its ordered phase, and that the system can exhibit complete rotations are all verified experimentally. We expect that similar oscillatory modes emerge in collective motion scenarios where the structure of the environment imposes conflicts between individually held information and the group’s tendency for cohesiveness. PMID:27930304

  15. The other ex ante moral hazard in health.

    PubMed

    Bhattacharya, Jay; Packalen, Mikko

    2012-01-01

    It is well-known that pooled insurance coverage can induce people to make inefficiently low investments in self-protective activities. We identify another ex ante moral hazard that runs in the opposite direction. Lower levels of self-protection and the associated chronic conditions and behavioral patterns such as obesity, smoking, and malnutrition increase the incidence of many diseases and consumption of treatments to those diseases. This increases the reward for innovation and thus benefits the innovator. It also increases treatment innovation which benefits all consumers. As individuals do not take these positive externalities into account, their investments in self-protection are inefficiently high. We quantify the lower bound of this externality for obesity. The lower bound is independent of how much additional innovation is generated. The results show that the externality we identify offsets the negative Medicare-induced insurance externality of obesity. The Medicare-induced obesity subsidy is thus not a sufficient rationale for "soda taxes", "fat taxes" or other penalties on obesity. The quantitative finding also implies that the other ex ante moral hazard that we identify can be as important as the ex ante moral hazard that has been a central concept in health economics for decades. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. The Other Ex-Ante Moral Hazard in Health*

    PubMed Central

    Bhattacharya, Jay; Packalen, Mikko

    2017-01-01

    It is well-known that pooled insurance coverage can induce people to make inefficiently low investments in self-protective activities. We identify another ex-ante moral hazard that runs in the opposite direction. Lower levels of self-protection and the associated chronic conditions and behavioral patterns such as obesity, smoking, and malnutrition increase the incidence of many diseases and consumption of treatments to those diseases. This increases the reward for innovation and thus benefits the innovator. It also increases treatment innovation which benefits all consumers. As individuals do not take these positive externalities into account, their investments in self-protection are inefficiently high. We quantify the lower bound of this externality for obesity. The lower bound is independent of how much additional innovation is generated. The results show that the externality we identify offsets the negative Medicare-induced insurance externality of obesity. The Medicare-induced obesity subsidy is thus not a sufficient rationale for “soda taxes”, “fat taxes” or other penalties on obesity. The quantitative finding also implies that the other ex-ante moral hazard that we identify can be as important as the ex-ante moral hazard that has been a central concept in health economics for decades. PMID:21993331

  17. Bioturbation by the Fungus-Gardening Ant, Trachymyrmex septentrionalis.

    PubMed

    Tschinkel, Walter R; Seal, Jon N

    2016-01-01

    Soil invertebrates such as ants are thought to be important manipulators of soils in temperate and tropical ecosystems. The fungus gardening ant, Trachymyrmex septentrionalis, is an important agent of biomantling, that is, of depositing soil excavated from below onto the surface, and has been suggested as an agent of bioturbation (moving soil below ground) as well. The amount of bioturbation by this ant was quantified by planting queenright colonies in sand columns consisting of 5 layers of different colored sand. The amount of each color of sand deposited on the surface was determined from April to November 2015. In November, colonies were excavated and the color and amount of sand deposited below ground (mostly as backfill in chambers) was determined. Extrapolated to one ha, T. septentrionalis deposited 800 kg of sand per annum on the surface, and an additional 200 kg (17% of the total excavated) below ground. On average, this mixes 1.3% of the sand from other layers within the top meter of soil per millennium, but this mixing is unlikely to be homogeneous, and probably occurs as "hotspots" in both horizontal and vertical space. Such mixing is discussed as a challenge to sediment dating by optically stimulated luminescence (OSL).

  18. Positive selection on sociobiological traits in invasive fire ants.

    PubMed

    Privman, Eyal; Cohen, Pnina; Cohanim, Amir B; Riba-Grognuz, Oksana; Shoemaker, DeWayne; Keller, Laurent

    2018-06-19

    The fire ant Solenopsis invicta and its close relatives are highly invasive. Enhanced social cooperation may facilitate invasiveness in these and other invasive ant species. We investigated whether invasiveness in Solenopsis fire ants was accompanied by positive selection on sociobiological traits by applying a phylogenomics approach to infer ancient selection, and a population genomics approach to infer recent and ongoing selection in both native and introduced S. invicta populations. A combination of whole-genome sequencing of 40 haploid males and reduced-representation genomic sequencing of 112 diploid workers identified 1,758,116 and 169,682 polymorphic markers, respectively. The resulting high-resolution maps of genomic polymorphism provide high inference power to test for positive selection. Our analyses provide evidence of positive selection on putative ion channel genes, which are implicated in neurological functions, and on vitellogenin, which is a key regulator of development and caste determination. Furthermore, molecular functions implicated in pheromonal signaling have experienced recent positive selection. Genes with signatures of positive selection were significantly more often those over-expressed in workers compared with queens and males, suggesting that worker traits are under stronger selection than queen and male traits. These results provide insights into selection pressures and ongoing adaptation in an invasive social insect and support the hypothesis that sociobiological traits are under more positive selection than traits related to non-social traits in such invasive species. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  19. Rationality in collective decision-making by ant colonies.

    PubMed

    Edwards, Susan C; Pratt, Stephen C

    2009-10-22

    Economic models of animal behaviour assume that decision-makers are rational, meaning that they assess options according to intrinsic fitness value and not by comparison with available alternatives. This expectation is frequently violated, but the significance of irrational behaviour remains controversial. One possibility is that irrationality arises from cognitive constraints that necessitate short cuts like comparative evaluation. If so, the study of whether and when irrationality occurs can illuminate cognitive mechanisms. We applied this logic in a novel setting: the collective decisions of insect societies. We tested for irrationality in colonies of Temnothorax ants choosing between two nest sites that varied in multiple attributes, such that neither site was clearly superior. In similar situations, individual animals show irrational changes in preference when a third relatively unattractive option is introduced. In contrast, we found no such effect in colonies. We suggest that immunity to irrationality in this case may result from the ants' decentralized decision mechanism. A colony's choice does not depend on site comparison by individuals, but instead self-organizes from the interactions of multiple ants, most of which are aware of only a single site. This strategy may filter out comparative effects, preventing systematic errors that would otherwise arise from the cognitive limitations of individuals.

  20. Effect of irradiation on queen survivorship and reproduction in the invasive fire ant Solenopsis invicta,(Hymenoptera: Formicidae) and a generic phytosanitary irradiation treatment for ants

    USDA-ARS?s Scientific Manuscript database

    Ants are common hitchhiker pests on traded agricultural commodities that could be controlled by postharvest irradiation treatment. We studied radiation tolerance in queens of the red imported fire ant Solenopsis invicta Buren to determine the dose sufficient for its control. Virgin or fertile queens...

  1. The effects of ant nests on soil fertility and plant performance: a meta-analysis.

    PubMed

    Farji-Brener, Alejandro G; Werenkraut, Victoria

    2017-07-01

    Ants are recognized as one of the major sources of soil disturbance world-wide. However, this view is largely based on isolated studies and qualitative reviews. Here, for the first time, we quantitatively determined whether ant nests affect soil fertility and plant performance, and identified the possible sources of variation of these effects. Using Bayesian mixed-models meta-analysis, we tested the hypotheses that ant effects on soil fertility and plant performance depend on the substrate sampled, ant feeding type, latitude, habitat and the plant response variable measured. Ant nests showed higher nutrient and cation content than adjacent non-nest soil samples, but similar pH. Nutrient content was higher in ant refuse materials than in nest soils. The fertilizer effect of ant nests was also higher in dry habitats than in grasslands or savannas. Cation content was higher in nests of plant-feeding ants than in nests of omnivorous species, and lower in nests from agro-ecosystems than in nests from any other habitat. Plants showed higher green/root biomass and fitness on ant nests soils than in adjacent, non-nest sites; but plant density and diversity were unaffected by the presence of ant nests. Root growth was particularly higher in refuse materials than in ant nest soils, in leaf-cutting ant nests and in deserts habitats. Our results confirm the major role of ant nests in influencing soil fertility and vegetation patterns and provide information about the factors that mediate these effects. First, ant nests improve soil fertility mainly through the accumulation of refuse materials. Thus, different refuse dump locations (external or in underground nest chambers) could benefit different vegetation life-forms. Second, ant nests could increase plant diversity at larger spatial scales only if the identity of favoured plants changes along environmental gradients (i.e. enhancing β-diversity). Third, ant species that feed on plants play a relevant role fertilizing soils

  2. Red imported fire ant impacts on upland arthropods in Southern Mississippi

    USGS Publications Warehouse

    Epperson, D.M.; Allen, Craig R.

    2010-01-01

    Red imported fire ants (Solenopsis invicta) have negative impacts on a broad array of invertebrate species. We investigated the impacts of fire ants on the upland arthropod community on 20???40 ha study sites in southern Mississippi. Study sites were sampled from 19972000 before, during, and after fire ant bait treatments to reduce fire ant populations. Fire ant abundance was assessed with bait transects on all sites, and fire ant population indices were estimated on a subset of study sites. Species richness and diversity of other ant species was also assessed from bait transects. Insect biomass and diversity was determined from light trap samples. Following treatments, fire ant abundance and population indices were significantly reduced, and ant species diversity and richness were greater on treated sites. Arthropod biomass, species diversity and species richness estimated from light trap samples were negatively correlated with fire ant abundance, but there were no observable treatment effects. Solenopsis invicta has the potential to negatively impact native arthropod communities resulting in a potential loss of both species and function.

  3. Ants as vectors of pathogenic microorganisms in a hospital in São Paulo county, Brazil.

    PubMed

    Máximo, Heros J; Felizatti, Henrique L; Ceccato, Marcela; Cintra-Socolowski, Priscila; Beretta, Ana Laura R Zeni

    2014-08-20

    The present study aimed to identify and characterize the presence of bacteria carried by ants, and check the distribution of these ants in the physical confines of a medium-sized hospital in São Paulo county, Brazil. The ants were collected from March 2012 to February 2013. Attractive non-toxic baits were used to catch the ants, and the sectors considered for the study were medical wards, outdoor areas, obstetric unit, reception area, kitchen, surgical centres, paediatric clinic and intensive care unit. Captured ants were classified using taxonomic keys and subsequently immersed in Brain Heart Infusion broth. Paratrechina spp. and Monomorium floricola ants were found most frequently in the hospital. Ants had a high capacity for carrying bacteria, and the isolates comprised 68.8% Gram-positive, spore-producing bacilli (Bacillus spp. and Listeria spp.); 14.7% Gram-negative bacilli (Pseudomonas aeruginosa and Klebsiella spp.); and 16.4% Gram-positive cocci (Streptococcus spp. and Staphylococcus aureus). Among the areas being evaluated, the medical wards had the largest number of ants captured, and therefore the most bacteria. Ants in hospitals may carry both Gram-positive and Gram-negative bacteria, and methods of controlling urban ants should be adopted and strictly adhered to, to minimize the risk of infection in hospital patients.

  4. Efficacy of Chemical Mimicry by Aphid Predators Depends on Aphid-Learning by Ants.

    PubMed

    Hayashi, Masayuki; Nomura, Masashi; Nakamuta, Kiyoshi

    2016-03-01

    Chemical mimicry is an effective strategy when signal receivers recognize and discriminate models by relying on chemical cues. Some aphid enemies mimic the cuticular chemicals of aphids through various means thus avoiding detection and attack by aphid-tending ants. However, because ants have been reported to learn the chemical signatures of aphids in order to distinguish the aphids, the efficacy of chemical mimicry is predicted to depend on the experience of the ants that had tended aphids. The present study tested this hypothesis using two predator species: larvae of the green lacewing Mallada desjardinsi, and larvae of the ladybeetle Scymnus posticalis. Lacewing larvae carry the carcasses of aphids on which they have preyed upon their backs, and these function via chemical camouflage to reduce the aggressiveness of aphid-tending ants toward the larvae. Ladybeetle larvae reportedly produce a covering of wax structures, and their chemicals appear to attenuate ant aggression. We examined whether the behavior of the ant Tetramorium tsushimae toward these predators changed depending on their aphid-tending experience. Ants moderated their aggressiveness toward both predators when they had previously tended aphids, indicating that chemical mimicry by both aphid predators is dependent on previous experience of the ants in tending aphids. Chemical mimicry by the predators of ant-tended aphids is therefore considered to exploit learning-dependent aphid recognition systems of ants.

  5. Navigation in wood ants Formica japonica: context dependent use of landmarks.

    PubMed

    Fukushi, Tsukasa; Wehner, Rüdiger

    2004-09-01

    Wood ants Formica japonica can steer their outbound (foraging) and inbound (homing) courses without using celestial compass information, by relying exclusively on landmark cues. This is shown by training ants to run back and forth between the nest and an artificial feeder, and later displacing the trained ants either from the nest (when starting their foraging runs: outbound full-vector ants) or from the feeder (when starting their home runs: inbound full-vector ants) to various nearby release sites. In addition, ants that have already completed their foraging and homing runs are displaced after arrival either at the feeder (outbound zero-vector ants) or at the nest (inbound zero-vector ants), respectively, to the very same release sites. Upon release, the full-vector ants steer their straight courses by referring to panoramic landmark cues, while the zero-vector ants presented with the very same visual scenery immediately search for local landmark cues defining their final goal. Hence, it depends on the context, in this case on the state of the forager's round-trip cycle, what visual cues are picked out from a given set of landmarks and used for navigation.

  6. Ant community change across a ground vegetation gradient in north Florida's longleaf pine flatwoods

    PubMed Central

    Lubertazzi, David; Tschinkel, Walter R.

    2003-01-01

    Ant communities in longleaf pine habitats are poorly known and hence the naturally occurring ant assemblages of a large portion of southeastern North America are not well understood. This study examined the diverse ant community found in the longleaf pine flatwoods of north Florida and tested how ant diversity changes along a herbaceous ground cover gradient. Restoring the ground cover to its original floral composition is an important focus of longleaf pine conservation and hence it is important to understand how native faunal communities vary with ground cover variation. Using 4 sampling methods, we characterized the ant community and analyzed its within-habitat variation among 12 study sites. We found the highest plot species richness (55 species) and within-habitat species richness (72 species) ever recorded for North American ants. The ants formed three distinct communities. The low-diversity arboreal and subterranean assemblages varied little across forest stands while the diversity of the species-rich ground foraging ant community was negatively correlated with percent herbaceous cover. The imported fire ant, Solenopsis invicta (monogyne form), was unexpectedly found to be abundant in high herbaceous cover sites. Floral restoration of the pine flatwoods, which is increasing the proportion of herbaceous cover, is likely to cause an increase in the abundance of the imported fire ant. Abbreviation: ANF Apalachicola National Forest PMID:15841237

  7. Evolutionary patterns of proteinase activity in attine ant fungus gardens

    PubMed Central

    2011-01-01

    Background Attine ants live in symbiosis with a basidiomycetous fungus that they rear on a substrate of plant material. This indirect herbivory implies that the symbiosis is likely to be nitrogen deprived, so that specific mechanisms may have evolved to enhance protein availability. We therefore hypothesized that fungal proteinase activity may have been under selection for efficiency and that different classes of proteinases might be involved. Results We determined proteinase activity profiles across a wide pH range for fungus gardens of 14 Panamanian species of fungus-growing ants, representing eight genera. We mapped these activity profiles on an independently obtained molecular phylogeny of the symbionts and show that total proteinase activity in lower attine symbionts peaks at ca. pH 6. The higher attine symbionts that have no known free-living relatives had much higher proteinase activities than the lower attine symbionts. Their total in vitro proteinase activity peaked at pH values around 5, which is close to the pH that the ants maintain in their fungus gardens, suggesting that the pH optimum of fungal proteinases may have changed after the irreversible domestication of evolutionary more derived fungal symbionts. This notion is also supported by buffering capacities of fungus gardens at pH 5.2 being remarkably high, and suggests that the fungal symbiont actively helps to maintain garden acidity at this specific level. Metalloproteinases dominated the activity profiles of lower attine gardens and may thus represent the ancestral type of proteinase production, whereas serine proteinase activity dominated the activity profiles of the higher attine gardens reared by Trachymyrmex and Sericomyrmex, suggesting that there may be trade-offs in the production of these enzyme classes. Remarkably, the single symbiont that is shared by species of the crown group of Atta and Acromyrmex leaf-cutting ants mostly showed metalloproteinase activity, suggesting that recurrent

  8. The Organization of Foraging in the Fire Ant, Solenopsis invicta

    PubMed Central

    Tschinkel, Walter R.

    2011-01-01

    Although natural selection in ants acts most strongly at the colony, or superorganismal level, foraging patterns have rarely been studied at that level, focusing instead on the behavior of individual foragers or groups of foragers. The experiments and observations in this paper reveal in broad strokes how colonies of the fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), allocate their available labor to foraging, how they disperse that force within their territory, and how this force changes with colony size, season and worker age. Territory area is positively related to colony size and the number of foragers, more so during the spring than fall. Changes of colony size and territory area are driven by seasonal variation of sexual and worker production, which in turn drive seasonal variation of worker age-distribution. During spring sexual production, colonies shrink because worker production falls below replacement. This loss is proportional to colony size, causing forager density in the spring to be negatively related to colony and territory size. In the fall, colonies emphasize worker production, bringing colony size back up. However, because smaller colonies curtailed spring worker production less than larger ones, their fall forager populations are proportionally greater, causing them to gain territory at the expense of large colonies. Much variation of territory area remains unexplained and can probably be attributed to pressure from neighboring colonies. Boundaries between territories are characterized by “no ants' zones” mostly devoid of fire ants. The forager population can be divided into a younger group of recruitable workers that wait for scouts to activate them to help retrieve large food finds. About one-third of the recruits wait near openings in the foraging tunnels that underlie the entire territory, while two-thirds wait in the nest. Recruitment to food is initially very rapid and local from the foraging tunnels, while sustained

  9. A specialist herbivore uses chemical camouflage to overcome the defenses of an ant-plant mutualism.

    PubMed

    Whitehead, Susan R; Reid, Ellen; Sapp, Joseph; Poveda, Katja; Royer, Anne M; Posto, Amanda L; Kessler, André

    2014-01-01

    Many plants and ants engage in mutualisms where plants provide food and shelter to the ants in exchange for protection against herbivores and competitors. Although several species of herbivores thwart ant defenses and extract resources from the plants, the mechanisms that allow these herbivores to avoid attack are poorly understood. The specialist insect herbivore, Piezogaster reclusus (Hemiptera: Coreidae), feeds on Neotropical bull-horn acacias (Vachellia collinsii) despite the presence of Pseudomyrmex spinicola ants that nest in and aggressively defend the trees. We tested three hypotheses for how P. reclusus feeds on V. collinsii while avoiding ant attack: (1) chemical camouflage via cuticular surface compounds, (2) chemical deterrence via metathoracic defense glands, and (3) behavioral traits that reduce ant detection or attack. Our results showed that compounds from both P. reclusus cuticles and metathoracic glands reduce the number of ant attacks, but only cuticular compounds appear to be essential in allowing P. reclusus to feed on bull-horn acacia trees undisturbed. In addition, we found that ant attack rates to P. reclusus increased significantly when individuals were transferred between P. spinicola ant colonies. These results are consistent with the hypothesis that chemical mimicry of colony-specific ant or host plant odors plays a key role in allowing P. reclusus to circumvent ant defenses and gain access to important resources, including food and possibly enemy-free space. This interaction between ants, acacias, and their herbivores provides an excellent example of the ability of herbivores to adapt to ant defenses of plants and suggests that herbivores may play an important role in the evolution and maintenance of mutualisms.

  10. Ants have a negative rather than a positive effect on extrafloral nectaried Crotalaria pallida performance

    NASA Astrophysics Data System (ADS)

    Pereira, Marcela Fernandes; Trigo, José Roberto

    2013-08-01

    Crotalaria pallida (Fabaceae) is a pantropical plant with extrafloral nectaries (EFNs) near the reproductive structures. EFN-visiting ants attack and remove arctiid moth Utetheisa ornatrix larvae, the main pre-dispersal seed predator, but the impact of ants on C. pallida fitness is unknown. To assess this impact, we controlled ant presence on plants and evaluated the reproductive output of C. pallida with and without ants. Predatory wasps also visit EFNs, prey upon U. ornatrix larvae, and may be driven out by ants during EFN feeding. Does this agonistic interaction affect the multitrophic interaction outcome? We found it difficult to evaluate the effect of both visitors because cages excluding wasps affect plant growth and do not allow U. ornatrix oviposition. Therefore, we verified whether ant presence inhibited wasp EFN visitation and predicted that (1) if ants confer a benefit for C. pallida, any negative effect of ants on wasps would be negligible for the plant because ants would be the best guardians, and (2) if ants are poor guardians, they would negatively affect wasps and negatively impact the fitness of C. pallida. Surprisingly, we found that the number of seeds/pods significantly increased, ca. 4.7 times, after ant removal. Additionally, we unexpectedly verified that controls showed a higher percentage of herbivore bored pods than ant-excluded plants. We found that wasps spent less time visiting EFNs patrolled by ants (ca. 299 s less). These results support our second prediction and suggest that the outcome of multitrophic interactions may vary with natural enemy actors.

  11. A Specialist Herbivore Uses Chemical Camouflage to Overcome the Defenses of an Ant-Plant Mutualism

    PubMed Central

    Whitehead, Susan R.; Reid, Ellen; Sapp, Joseph; Poveda, Katja; Royer, Anne M.; Posto, Amanda L.; Kessler, André

    2014-01-01

    Many plants and ants engage in mutualisms where plants provide food and shelter to the ants in exchange for protection against herbivores and competitors. Although several species of herbivores thwart ant defenses and extract resources from the plants, the mechanisms that allow these herbivores to avoid attack are poorly understood. The specialist insect herbivore, Piezogaster reclusus (Hemiptera: Coreidae), feeds on Neotropical bull-horn acacias (Vachellia collinsii) despite the presence of Pseudomyrmex spinicola ants that nest in and aggressively defend the trees. We tested three hypotheses for how P. reclusus feeds on V. collinsii while avoiding ant attack: (1) chemical camouflage via cuticular surface compounds, (2) chemical deterrence via metathoracic defense glands, and (3) behavioral traits that reduce ant detection or attack. Our results showed that compounds from both P. reclusus cuticles and metathoracic glands reduce the number of ant attacks, but only cuticular compounds appear to be essential in allowing P. reclusus to feed on bull-horn acacia trees undisturbed. In addition, we found that ant attack rates to P. reclusus increased significantly when individuals were transferred between P. spinicola ant colonies. These results are consistent with the hypothesis that chemical mimicry of colony-specific ant or host plant odors plays a key role in allowing P. reclusus to circumvent ant defenses and gain access to important resources, including food and possibly enemy-free space. This interaction between ants, acacias, and their herbivores provides an excellent example of the ability of herbivores to adapt to ant defenses of plants and suggests that herbivores may play an important role in the evolution and maintenance of mutualisms. PMID:25047551

  12. Ants Learn Aphid Species as Mutualistic Partners: Is the Learning Behavior Species-Specific?

    PubMed

    Hayashi, Masayuki; Nakamuta, Kiyoshi; Nomura, Masashi

    2015-12-01

    In ant-aphid associations, many aphid species provide ants with honeydew and are tended by ants, whereas others are never tended and are frequently preyed upon by ants. In these relationships, ants must have the ability to discriminate among aphid species, with mutualistic aphids being accepted as partners rather than prey. Although ants reportedly use cuticular hydrocarbons (CHCs) of aphids to differentiate between mutualistic and non-mutualistic species, it is unclear whether the ability to recognize mutualistic aphid species as partners is innate or involves learning. Therefore, we tested whether aphid recognition by ants depends on learning, and whether the learning behavior is species-specific. When workers of the ant Tetramorium tsushimae had previously tended the cowpea aphid, Aphis craccivora, they were less aggressive toward this species. In addition, ants also reduced their aggressiveness toward another mutualistic aphid species, Aphis fabae, after tending A. craccivora, whereas ants remained aggressive toward the non-mutualistic aphid, Acyrthosiphon pisum, regardless of whether or not they had previous experience in tending A. craccivora. When ants were offered glass dummies treated with CHCs of these aphid species, ants that had tended A. craccivora displayed reduced aggression toward CHCs of A. craccivora and A. fabae. Chemical analyses showed the similarity of the CHC profiles between A. craccivora and A. fabae but not with A. pisum. These results suggest that aphid recognition of ants involves learning, and that the learning behavior may not be species-specific because of the similarity of CHCs between different aphid species with which they form mutualisms.

  13. Chemical disguise as particular caste of host ants in the ant inquiline parasite Niphanda fusca (Lepidoptera: Lycaenidae)

    PubMed Central

    Hojo, Masaru K.; Wada-Katsumata, Ayako; Akino, Toshiharu; Yamaguchi, Susumu; Ozaki, Mamiko; Yamaoka, Ryohei

    2008-01-01

    The exploitation of parental care is common in avian and insect ‘cuckoos’ and these species engage in a coevolutionary arms race. Caterpillars of the lycaenid butterfly Niphanda fusca develop as parasites inside the nests of host ants (Camponotus japonicus) where they grow by feeding on the worker trophallaxis. We hypothesized that N. fusca caterpillars chemically mimic host larvae, or some particular castes of the host ant, so that the caterpillars are accepted and cared for by the host workers. Behaviourally, it was observed that the host workers enthusiastically tended glass dummies coated with the cuticular chemicals of larvae or males and those of N. fusca caterpillars living together. Cuticular chemical analyses revealed that N. fusca caterpillars grown in a host ant nest acquired a colony-specific blend of cuticular hydrocarbons (CHCs). Furthermore, the CHC profiles of the N. fusca caterpillars were particularly close to those of the males rather than those of the host larvae and the others. We suggest that N. fusca caterpillars exploit worker care by matching their cuticular profile to that of the host males, since the males are fed by trophallaxis with workers in their natal nests for approximately ten months. PMID:18842547

  14. Survey of invasive ants at Hakalau Forest National Wildlife Refuge

    USGS Publications Warehouse

    Peck, Robert W.; Banko, Paul C.

    2011-01-01

    We conducted a survey for invasive ants at Hakalau Forest National Wildlife Refuge, Hawai‘i Island, during 2009–2010 to evaluate potential threats to native arthropod communities and food webs. The focal area of the survey was the upper portion of the Hakalau Unit of the refuge, where native forest was being restored in abandoned cattle pastures. This area, between 1575 and 1940 m elevations, contained much alien kikuyu grass (Pennisetum clandestinum), but koa (Acacia koa) trees and other native species that were planted in the past 20 years were rapidly filling in the pasture. We surveyed for ants at predetermined points along roads, fences, and corridors of planted koa. Sampling methods primarily consisted of hand searching and pitfall traps, but bait cards were used additionally in some instances. Our results indicated that a single species, Cardiocondyla kagutsuchi, was widespread across the upper portion of the refuge. Cardiocondyla kagutsuchi seemed absent, or at least rare, in areas of tall, dense grass. Due to the undulating topography of the area, however, the dense grass cover was interspersed with outcroppings of exposed, gravelly soil. Presumably due to warming by the sun, many of the outcropped habitats supported colonies of C. kagutsuchi. We did not detect ants in the old-growth forest below the abandoned pastures, presumably because microhabitat conditions under the forest canopy were unsuitable. Although ecological impacts of C. kagutsuchi have not been reported, they may be limited by the small size of the ant, the relatively small size of colonies, and the apparent preference of the ant for disturbed areas that are dominated by alien species. Notably, our survey of Keanakolu-Mana Road between the Observatory Road (John A. Burns Way) and the town of Waimea detected a population of Argentine ants (Linepithema humile) approximately 5.1 km north of the Maulua Section of the refuge. We also surveyed for ants on the Kona Forest Unit of the refuge

  15. Myrmecochores can target high-quality disperser ants: variation in elaiosome traits and ant preferences for myrmecochorous Euphorbiaceae in Brazilian Caatinga.

    PubMed

    Leal, Laura Carolina; Lima Neto, Mário Correia; de Oliveira, Antônio Fernando Morais; Andersen, Alan N; Leal, Inara R

    2014-02-01

    Recent evidence suggests that the traditional view of myrmecochory as a highly diffuse interaction between diaspores and a wide range of ant species attracted to their elaiosomes may not be correct. The effectiveness of dispersal varies markedly among ant species, and combined with differential attractiveness of diaspores due to elaiosome size and composition, this raises the potential for myrmecochorous plants to target ant species that offer the highest quality dispersal services. We ask the question: Do particular physical and chemical traits of elaiosomes result in disproportionate removal of Euphorbiaceae diaspores by high-quality disperser ants in Caatinga vegetation of north-eastern Brazil? We offered seeds of five euphorb species that varied in morphological and chemical traits of elaiosomes to seed-dispersing ants. High-quality seed-disperser ants (species of Dinoponera, Ectatomma and Camponotus) were identified as those that rapidly collected and transported diaspores to their nests, often over substantial distances, whereas low-quality disperser ants (primarily species of Pheidole and Solenopsis) typically fed on elaiosomes in situ, and only ever transported diaspores very short distances. Low-quality disperser ants were equally attracted to the elaiosomes of all study species. However, high-quality dispersers showed a strong preference for diaspores with the highest elaiosome mass (and especially proportional mass). As far as we are aware, this is the first study to identify a mechanism of diaspore selection by high-quality ant dispersers based on elaiosome traits under field conditions. Our findings suggest that myrmecochorous plants can preferentially target high-quality seed-disperser ants through the evolution of particular elaiosome traits.

  16. A novel type of nutritional ant-plant interaction: ant partners of carnivorous pitcher plants prevent nutrient export by dipteran pitcher infauna.

    PubMed

    Scharmann, Mathias; Thornham, Daniel G; Grafe, T Ulmar; Federle, Walter

    2013-01-01

    Many plants combat herbivore and pathogen attack indirectly by attracting predators of their herbivores. Here we describe a novel type of insect-plant interaction where a carnivorous plant uses such an indirect defence to prevent nutrient loss to kleptoparasites. The ant Camponotus schmitzi is an obligate inhabitant of the carnivorous pitcher plant Nepenthes bicalcarata in Borneo. It has recently been suggested that this ant-plant interaction is a nutritional mutualism, but the detailed mechanisms and the origin of the ant-derived nutrient supply have remained unexplained. We confirm that N. bicalcarata host plant leaves naturally have an elevated (15)N/(14)N stable isotope abundance ratio (δ(15)N) when colonised by C. schmitzi. This indicates that a higher proportion of the plants' nitrogen is insect-derived when C. schmitzi ants are present (ca. 100%, vs. 77% in uncolonised plants) and that more nitrogen is available to them. We demonstrated direct flux of nutrients from the ants to the host plant in a (15)N pulse-chase experiment. As C. schmitzi ants only feed on nectar and pitcher contents of their host, the elevated foliar δ(15)N cannot be explained by classic ant-feeding (myrmecotrophy) but must originate from a higher efficiency of the pitcher traps. We discovered that C. schmitzi ants not only increase the pitchers' capture efficiency by keeping the pitchers' trapping surfaces clean, but they also reduce nutrient loss from the pitchers by predating dipteran pitcher inhabitants (infauna). Consequently, nutrients the pitchers would have otherwise lost via emerging flies become available as ant colony waste. The plants' prey is therefore conserved by the ants. The interaction between C. schmitzi, N. bicalcarata and dipteran pitcher infauna represents a new type of mutualism where animals mitigate the damage by nutrient thieves to a plant.

  17. Effect of exit locations on ants escaping a two-exit room stressed with repellent

    NASA Astrophysics Data System (ADS)

    Wang, Shujie; Cao, Shuchao; Wang, Qiao; Lian, Liping; Song, Weiguo

    2016-09-01

    In order to investigate the effect of the distance between two exits on ant evacuation efficiency and the behavior of ants escaping from a two-exit room, we conducted ant egress experiments using Camponotus japonicus in multiple situations. We found that the ants demonstrated the phenomenon of "symmetry breaking" in this stress situation. It was also shown that different locations for the exits obviously affected the ants' egress efficiency by measuring the time intervals between individual egress and flow rate in eight repeated experiments, each of which contained five different distance between the two exits. In addition, it is demonstrated that there are differences between the predictions of Social Force Model of pedestrians and the behaviors of ants in stress conditions through comparing some important behavioral features, including position, trajectory, velocity, and density map.

  18. Imaging with Mass Spectrometry of Bacteria on the Exoskeleton of Fungus-Growing Ants.

    PubMed

    Gemperline, Erin; Horn, Heidi A; DeLaney, Kellen; Currie, Cameron R; Li, Lingjun

    2017-08-18

    Mass spectrometry imaging is a powerful analytical technique for detecting and determining spatial distributions of molecules within a sample. Typically, mass spectrometry imaging is limited to the analysis of thin tissue sections taken from the middle of a sample. In this work, we present a mass spectrometry imaging method for the detection of compounds produced by bacteria on the outside surface of ant exoskeletons in response to pathogen exposure. Fungus-growing ants have a specialized mutualism with Pseudonocardia, a bacterium that lives on the ants' exoskeletons and helps protect their fungal garden food source from harmful pathogens. The developed method allows for visualization of bacterial-derived compounds on the ant exoskeleton. This method demonstrates the capability to detect compounds that are specifically localized to the bacterial patch on ant exoskeletons, shows good reproducibility across individual ants, and achieves accurate mass measurements within 5 ppm error when using a high-resolution, accurate-mass mass spectrometer.

  19. The significance of direct sunlight and polarized skylight in the ant's celestial system of navigation.

    PubMed

    Wehner, Rüdiger; Müller, Martin

    2006-08-15

    As textbook knowledge has it, bees and ants use polarized skylight as a backup cue whenever the main compass cue, the sun, is obscured by clouds. Here we show, by employing a unique experimental paradigm, that the celestial compass system of desert ants, Cataglyphis, relies predominantly on polarized skylight. If ants experience only parts of the polarization pattern during training but the full pattern in a subsequent test situation, they systematically deviate from their true homeward courses, with the systematics depending on what parts of the skylight patterns have been presented during training. This "signature" of the polarization compass remains unaltered, even if the ants can simultaneously experience the sun, which, if presented alone, enables the ants to select their true homeward courses. Information provided by direct sunlight and polarized skylight is picked up by different parts of the ant's compound eyes and is channeled into two rather separate systems of navigation.

  20. Ant colony clustering with fitness perception and pheromone diffusion for community detection in complex networks

    NASA Astrophysics Data System (ADS)

    Ji, Junzhong; Song, Xiangjing; Liu, Chunnian; Zhang, Xiuzhen

    2013-08-01

    Community structure detection in complex networks has been intensively investigated in recent years. In this paper, we propose an adaptive approach based on ant colony clustering to discover communities in a complex network. The focus of the method is the clustering process of an ant colony in a virtual grid, where each ant represents a node in the complex network. During the ant colony search, the method uses a new fitness function to percept local environment and employs a pheromone diffusion model as a global information feedback mechanism to realize information exchange among ants. A significant advantage of our method is that the locations in the grid environment and the connections of the complex network structure are simultaneously taken into account in ants moving. Experimental results on computer-generated and real-world networks show the capability of our method to successfully detect community structures.

  1. Attracting predators without falling prey: chemical camouflage protects honeydew-producing treehoppers from ant predation.

    PubMed

    Silveira, Henrique C P; Oliveira, Paulo S; Trigo, José R

    2010-02-01

    Predaceous ants are dominant organisms on foliage and represent a constant threat to herbivorous insects. The honeydew of sap-feeding hemipterans has been suggested to appease aggressive ants, which then begin tending activities. Here, we manipulated the cuticular chemical profiles of freeze-dried insect prey to show that chemical background matching with the host plant protects Guayaquila xiphias treehoppers against predaceous Camponotus crassus ants, regardless of honeydew supply. Ant predation is increased when treehoppers are transferred to a nonhost plant with which they have low chemical similarity. Palatable moth larvae manipulated to match the chemical background of Guayaquila's host plant attracted lower numbers of predatory ants than unchanged controls. Although aggressive tending ants can protect honeydew-producing hemipterans from natural enemies, they may prey on the trophobionts under shortage of alternative food resources. Thus chemical camouflage in G. xiphias allows the trophobiont to attract predaceous bodyguards at reduced risk of falling prey itself.

  2. Can anthropic fires affect epigaeic and hypogaeic Cerrado ant (Hymenoptera: Formicidae) communities in the same way?

    PubMed

    Canedo-Júnior, Ernesto de Oliveira; Cuissi, Rafael Gonçalves; Nelson Henrique de Almeida, Curi; Demetrio, Guilherme Ramos; Lasmar, Chaim José; Malves, Kira

    2016-03-01

    Fire occurrences are a common perturbation in Cerrado ecosystems, and may differently impact the local biodiversity. Arthropods are one of the taxa affected by fires, and among them, ants are known as good bioindicators. We aimed to evaluate the effect of anthropic fires on epigaeic and hypogaeic ant communities (species richness and composition) in Cerrado areas with different post-fire event recovery periods. We conducted the study in four Cerrado areas during two weeks of 2012 dry season: one unburned and three at different post-fire times (one month, one and two years). We sampled ants with pitfall traps in epigaeic and hypogaeic microhabitats. We collected 71 ant morpho-species from 25 genera. In the epigaeic microhabitat we sampled 56 morpho-species and 42 in the hypogaeic microhabitat. The area with the shortest recovery time presented lower epigaeic ant species richness (4.3 ± 2.00) in comparison to the other areas (8.1 ± 2.68 species on one year area; 10.3 ± 2.66 species on two years area; 10.4 ± 2.31 species on control area), but recovery time did not affect hypogaeic ant species richness. Regarding ant species composition, fire did not directly affect hypogaeic ant species, which remained the same even one month after fire event. However, two years were not enough to reestablish ant species composition in both microhabitats in relation to our control group samples. Our study is the first to assess anthropic fire effects upon epigaeic and hypogaeic ants communities; highlighting the importance of evaluating different microhabitats, to more accurately detect the effects of anthropic disturbances in biological communities. We concluded that ant communities are just partially affected by fire occurrences, and epigaeic assemblages are the most affected ones in comparison to hypogaeic ants. Furthermore the study provides knowledge to aid in the creation of vegetation management programs that allow Cerrado conservation.

  3. Detection of magnetism in the red imported fire ant (Solenopsis invicta) using magnetic resonance imaging.

    PubMed

    Slowik, T J; Green, B L; Thorvilson, H G

    1997-01-01

    Red imported fire ant (Solenopsis invicta) workers, queens, and alates were analyzed by magnetic resonance imaging (MRI) for the presence of natural magnetism. Images of ants showed distortion patterns similar to those of honey bees and monarch butterflies, both of which possess ferromagnetic material. The bipolar ring patterns of MRI indicated the presence in fire ants of small amounts of internal magnetic material, which may be used in orientation behaviors, as in the honey bees.

  4. Biotic and abiotic controls of argentine ant invasion success at local and landscape scales

    USGS Publications Warehouse

    Menke, S.B.; Fisher, R.N.; Jetz, W.; Holway, D.A.

    2007-01-01

    Although the ecological success of introduced species hinges on biotic interactions and physical conditions, few experimental studies - especially on animals - have simultaneously investigated the relative importance of both types of factors. The lack of such research may stem from the common assumption that native and introduced species exhibit similar environmental tolerances. Here we combine experimental and spatial modeling approaches (1) to determine the relative importance of biotic and abiotic controls of Argentine ant (Linepithema humile) invasion success, (2) to examine how the importance of these factors changes with spatial scale in southern California (USA), and (3) to assess how Argentine ants differ from native ants in their environmental tolerances. A factorial field experiment that combined native ant removal with irrigation revealed that Argentine ants failed to invade any dry plots (even those lacking native ants) but readily invaded all moist plots. Native ants slowed the spread of Argentine ants into irrigated plots but did not prevent invasion. In areas without Argentine ants, native ant species showed variable responses to irrigation. At the landscape scale, Argentine ant occurrence was positively correlated with minimum winter temperature (but not precipitation), whereas native ant diversity increased with precipitation and was negatively correlated with minimum winter temperature. These results are of interest for several reasons. First, they demonstrate that fine-scale differences in the physical environment can eclipse biotic resistance from native competitors in determining community susceptibility to invasion. Second, our results illustrate surprising complexities with respect to how the abiotic factors limiting invasion can change with spatial scale, and third, how native and invasive species can differ in their responses to the physical environment. Idiosyncratic and scale-dependent processes complicate attempts to forecast where

  5. Steep Decline and Cessation in Seed Dispersal by Myrmica rubra Ants.

    PubMed

    Bologna, Audrey; Detrain, Claire

    2015-01-01

    Myrmecochorous diaspores bear a nutrient-rich appendage, the elaiosome, attractive to ant workers that retrieve them into the nest, detach the elaiosome and reject the seed intact. While this interaction is beneficial for the plant partner by ensuring its seed dispersal, elaiosome consumption has various effects -positive, negative or none - on ants' demography and survival, depending on both the ant/plant species involved. In this context, the contribution of ants to seed dispersal strongly varies according to the ant/plant pairs considered. In this paper, we investigate whether the dynamics of myrmecochory also vary on a temporal scale, for a given pair of partners: Myrmica rubra ants and Viola odorata seeds. During their first encounter with seeds, ants collect all the diaspores and eat the majority of elaiosomes. Both the harvesting effort and the elaiosome consumption decline when seeds are offered on the next week and completely cease for the following weeks. This is related to a decrease in the number of foragers reaching the food source, as well as to a reduced probability for an ant contacting a seed to retrieve it. Seed retrieval is not reactivated after seven weeks without any encounter with V. odorata seeds. By contrast, naive ant colonies only fed with fruit flies do not show a decline of prey harvesting of which the speed of retrieval even increases over the successive weeks. Myrmecochory may thus be labile at the scale of a fruiting season due to the ability of ants to steeply tune and cease for several months the harvesting of these seemingly poorly rewarding items and to maintain cessation of seed exploitation. The present study emphasizes the importance of a long-lasting follow up of the myrmecochory process, to assess the stability of this ant-plant partnership and to identify mechanisms of adaptive harvesting in ants.

  6. Local and Landscape Drivers of Ant Parasitism in a Coffee Landscape.

    PubMed

    De la Mora, Aldo; Pérez-Lachaud, Gabriela; Lachaud, Jean-Paul; Philpott, Stacy M

    2015-08-01

    Parasitism of ants that nest in rotting wood by eucharitid wasps was studied in order to examine whether habitat and season influence ant parasitism, vegetation complexity and agrochemical use correlate with ant parasitism, and whether specific local and landscape features of agricultural landscapes correlate with changes in ant parasitism. In a coffee landscape, 30 coffee and 10 forest sites were selected in which local management (e.g., vegetation, agrochemical use) and landscape features (e.g., distance to forest, percent of rustic coffee nearby) were characterized. Rotten logs were sampled and ant cocoons were collected from logs and cocoons were monitored for parasitoid emergence. Sixteen ant morphospecies in three ant subfamilies (Ectatomminae, Ponerinae, and Formicinae) were found. Seven ant species parasitized by two genera of Eucharitidae parasitoids (Kapala and Obeza) were reported and some ant-eucharitid associations were new. According to evaluated metrics, parasitism did not differ with habitat (forest, high-shade coffee, low-shade coffee), but did increase in the dry season for Gnamptogenys ants. Parasitism increased with vegetation complexity for Gnamptogenys and Pachycondyla and was high in sites with both high and low agrochemical use. Two landscape variables and two local factors positively correlated with parasitism for some ant genera and species. Thus, differences in vegetation complexity at the local and landscape scale and agrochemical use in coffee landscapes alter ecological interactions between parasitoids and their ant hosts. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Individual-Based Ant-Plant Networks: Diurnal-Nocturnal Structure and Species-Area Relationship

    PubMed Central

    Dáttilo, Wesley; Fagundes, Roberth; Gurka, Carlos A. Q.; Silva, Mara S. A.; Vieira, Marisa C. L.; Izzo, Thiago J.; Díaz-Castelazo, Cecília; Del-Claro, Kleber; Rico-Gray, Victor

    2014-01-01

    Despite the importance and increasing knowledge of ecological networks, sampling effort and intrapopulation variation has been widely overlooked. Using continuous daily sampling of ants visiting three plant species in the Brazilian Neotropical savanna, we evaluated for the first time the topological structure over 24 h and species-area relationships (based on the number of extrafloral nectaries available) in individual-based ant-plant networks. We observed that diurnal and nocturnal ant-plant networks exhibited the same pattern of interactions: a nested and non-modular pattern and an average level of network specialization. Despite the high similarity in the ants’ composition between the two collection periods, ant species found in the central core of highly interacting species totally changed between diurnal and nocturnal sampling for all plant species. In other words, this “night-turnover” suggests that the ecological dynamics of these ant-plant interactions can be temporally partitioned (day and night) at a small spatial scale. Thus, it is possible that in some cases processes shaping mutualistic networks formed by protective ants and plants may be underestimated by diurnal sampling alone. Moreover, we did not observe any effect of the number of extrafloral nectaries on ant richness and their foraging on such plants in any of the studied ant-plant networks. We hypothesize that competitively superior ants could monopolize individual plants and allow the coexistence of only a few other ant species, however, other alternative hypotheses are also discussed. Thus, sampling period and species-area relationship produces basic information that increases our confidence in how individual-based ant-plant networks are structured, and the need to consider nocturnal records in ant-plant network sampling design so as to decrease inappropriate inferences. PMID:24918750

  8. Influence of the hypogaeic army ant Dorylus (Dichthadia) laevigatus on tropical arthropod communities.

    PubMed

    Berghoff, Stefanie M; Maschwitz, Ulrich; Linsenmair, K Eduard

    2003-03-01

    The majority of army ant species forage hypogaeically. Due to the difficulties in observing these ants, their potential influence on hypogaeic and epigaeic arthropod communities has not yet been investigated. As the first hypogaeically foraging army ant studied in detail, we attracted Dorylus laevigatus to areas monitored for their arthropod diversity. Here, for the first time, the same sites were sampled before and after an army ant raid. Furthermore, interactions between D. laevigatus and the five most common ground-nesting ant species were noted and their life-history traits compared, allowing first inferences on possible mechanisms of their coexistence. The occurrence of D. laevigatus within a study plot had no evident effect on the number of arthropod taxa or individuals collected with epigaeic and hypogaeic pitfall traps. Likewise, juvenile arthropods, which are less mobile and thus are potentially easier prey for D. laevigatus, showed no differences in their collected numbers before and after the army ant had visited a plot. However, significantly fewer ant species were collected with hypogaeic traps after D. laevigatus had been within the study plots, indicating a possible predation of D. laevigatus especially on two Pseudolasius and one Pheidole species. The five most common ground-foraging ant species demonstrated their ability to avoid, kill, and even prey on the army ant. The reaction of Lophomyrmex bedoti towards D. laevigatus indicated the former to be a potential prey species, while Pachycondyla sp. 2 showed signs of "enemy specification." Odontoponera diversus and O. transversa actively preyed on D. laevigatus, while Pheidologeton affinis fought with D. laevigatus over resources. All ant species could co-occur with D. laevigatus at palm oil baits. Adding to the differences detected in previous studies between D. laevigatus and epigaeically foraging army ant species, the occurrence of this hypogaeic army ant seems to have less devastating effects on

  9. Ants (Hymenoptera:Formicidae) of the Savannah River Plant, South Carolina

    SciTech Connect

    Van Pelt, A.; Gentry, J.B.

    1985-03-01

    This report lists each ant species collected on the SRP by habitat and, where determined, the nesting site within a particular habitat. Through the use of baited traps, relative frequencies of foraging ants were determined and listed. A key to the subfamilies and genera of ants occurring on the SRP is included along with illustrations of species representative of the major genera. 10 refs., 32 figs., 2 tabs.

  10. Desiccation resistance in tropical insects: causes and mechanisms underlying variability in a Panama ant community.

    PubMed

    Bujan, Jelena; Yanoviak, Stephen P; Kaspari, Michael

    2016-09-01

    Desiccation resistance, the ability of an organism to reduce water loss, is an essential trait in arid habitats. Drought frequency in tropical regions is predicted to increase with climate change, and small ectotherms are often under a strong desiccation risk. We tested hypotheses regarding the underexplored desiccation potential of tropical insects. We measured desiccation resistance in 82 ant species from a Panama rainforest by recording the time ants can survive desiccation stress. Species' desiccation resistance ranged from 0.7 h to 97.9 h. We tested the desiccation adaptation hypothesis, which predicts higher desiccation resistance in habitats with higher vapor pressure deficit (VPD) - the drying power of the air. In a Panama rainforest, canopy microclimates averaged a VPD of 0.43 kPa, compared to a VPD of 0.05 kPa in the understory. Canopy ants averaged desiccation resistances 2.8 times higher than the understory ants. We tested a number of mechanisms to account for desiccation resistance. Smaller insects should desiccate faster given their higher surface area to volume ratio. Desiccation resistance increased with ant mass, and canopy ants averaged 16% heavier than the understory ants. A second way to increase desiccation resistance is to carry more water. Water content was on average 2.5% higher in canopy ants, but total water content was not a good predictor of ant desiccation resistance or critical thermal maximum (CT max), a measure of an ant's thermal tolerance. In canopy ants, desiccation resistance and CT max were inversely related, suggesting a tradeoff, while the two were positively correlated in understory ants. This is the first community level test of desiccation adaptation hypothesis in tropical insects. Tropical forests do contain desiccation-resistant species, and while we cannot predict those simply based on their body size, high levels of desiccation resistance are always associated with the tropical canopy.

  11. Ant exclusion in citrus over an 8-year period reveals a pervasive yet changing effect of ants on a Mediterranean spider assemblage.

    PubMed

    Mestre, L; Piñol, J; Barrientos, J A; Espadaler, X

    2013-09-01

    Ants and spiders are ubiquitous generalist predators that exert top-down control on herbivore populations. Research shows that intraguild interactions between ants and spiders can negatively affect spider populations, but there is a lack of long-term research documenting the strength of such interactions and the potentially different effects of ants on the diverse array of species in a spider assemblage. Similarly, the suitability of family-level surrogates for finding patterns revealed by species-level data (taxonomic sufficiency) has almost never been tested in spider assemblages. We present a long-term study in which we tested the impact of ants on the spider assemblage of a Mediterranean citrus grove by performing sequential 1-year experimental exclusions on tree canopies for 8 years. We found that ants had a widespread influence on the spider assemblage, although the effect was only evident in the last 5 years of the study. During those years, ants negatively affected many spiders, and effects were especially strong for sedentary spiders. Analyses at the family level also detected assemblage differences between treatments, but they concealed the different responses to ant exclusion shown by some related spider species. Our findings show that the effects of experimental manipulations in ecology can vary greatly over time and highlight the need for long-term studies to document species interactions.

  12. The role of ant-tended extrafloral nectaries in the protection and benefit of a Neotropical rainforest tree.

    PubMed

    de la Fuente, Marie Ann S; Marquis, Robert J

    1999-02-01

    One possible function of extrafloral nectaries is to attract insects, particularly ants, which defend plants from herbivores. We determined whether ants visiting saplings of the tree Stryphnodendronmicrostachyum (Leguminosae) provide protection (decreased plant damage due to ant molestation or killing of herbivores) and benefit (increased plant growth and reproduction associated with ant presence) to the plant. We compared ant and herbivore abundance, herbivore damage and growth of ant-visited plants and ant-excluded plants grown in sun and shade microhabitats of a 6-ha plantation in Costa Rica over a 7-month period. Results show that ants provided protection to plants not by reducing herbivore numbers but by molesting herbivores. Ants also reduced the incidence of pathogen attack on leaves. Protection was greater in the shade than in the sun, probably due to lower herbivore attack in the sun. Protection was also variable within sun and shade habitats, and this variability appeared to be related to variable ant visitation. Results also indicate that ant presence benefits the plant: ant-visited plants grew significantly more in height than ant-excluded plants. The cultivation of ants may serve as an important natural biological control in tropical forestry and agroforestry systems, where increased plant density can otherwise lead to increased herbivore attack.

  13. The direct and ecological costs of an ant-plant symbiosis.

    PubMed

    Frederickson, Megan E; Ravenscraft, Alison; Miller, Gabriel A; Arcila Hernández, Lina M; Booth, Gregory; Pierce, Naomi E

    2012-06-01

    How strong is selection for cheating in mutualisms? The answer depends on the type and magnitude of the costs of the mutualism. Here we investigated the direct and ecological costs of plant defense by ants in the association between Cordia nodosa, a myrmecophytic plant, and Allomerus octoarticulatus, a phytoecious ant. Cordia nodosa trees produce food and housing to reward ants that protect them against herbivores. For nearly 1 year, we manipulated the presence of A. octoarticulatus ants and most insect herbivores on C. nodosa in a full-factorial experiment. Ants increased plant growth when herbivores were present but decreased plant growth when herbivores were absent, indicating that hosting ants can be costly to plants. However, we did not detect a cost to ant colonies of defending host plants against herbivores. Although this asymmetry in costs suggests that the plants may be under stronger selection than the ants to cheat by withholding investment in their partner, the costs to C. nodosa are probably at least partly ecological, arising because ants tend scale insects on their host plants. We argue that ecological costs should favor resistance or traits other than cheating and thus that neither partner may face much temptation to cheat.

  14. Bacteria may contribute to distant species recognition in ant-aphid mutualistic relationships.

    PubMed

    Fischer, Christophe Y; Detrain, Claire; Thonart, Philippe; Haubruge, Eric; Francis, Frédéric; Verheggen, François J; Lognay, Georges C

    2017-04-01

    Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  15. Development of virtual bait stations to control Argentine ants (Hymenoptera: Formicidae) in environmentally sensitive habitats.

    PubMed

    Choe, Dong-Hwan; Vetter, Richard S; Rust, Michael K

    2010-10-01

    A novel bait station referred to as a virtual bait station was developed and tested against field populations of the invasive Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae), at White Beach, Camp Pendleton, in Oceanside, CA. White Beach is a nesting habitat for an endangered seabird, the California least tern (Sterna antillarum browni Mearns). The beach is heavily infested with Argentine ants, one of the threats for the California least tern chicks. Conventional pest control strategies are prohibited because of the existence of the protected bird species and the site's proximity to the ocean. The bait station consisted of a polyvinyl chloride pipe that was treated on the inside with fipronil insecticide at low concentrations to obtain delayed toxicity against ants. The pipe was provisioned with an inverted bottle of 25% sucrose solution, then capped, and buried in the sand. Foraging ants crossed the treated surface to consume the sucrose solution. The delayed toxicity of fipronil deposits allowed the ants to continue foraging on the sucrose solution and to interact with their nestmates, killing them within 3-5 d after exposure. Further modification of the bait station design minimized the accumulation of dead ants in the sucrose solution, significantly improving the longevity and efficacy of the bait station. The virtual bait station exploits the foraging behavior of the ants and provides a low impact approach to control ants in environmentally sensitive habitats. It excluded all insects except ants, required only milligram quantities of toxicant, and eliminated the problem of formulating toxicants into aqueous sugar baits.

  16. Interaction specificity between leaf-cutting ants and vertically transmitted Pseudonocardia bacteria.

    PubMed

    Andersen, Sandra B; Yek, Sze Huei; Nash, David R; Boomsma, Jacobus J

    2015-02-25

    The obligate mutualism between fungus-growing ants and microbial symbionts offers excellent opportunities to study the specificity and stability of multi-species interactions. In addition to cultivating fungus gardens, these ants have domesticated actinomycete bacteria to defend gardens against the fungal parasite Escovopsis and possibly other pathogens. Panamanian Acromyrmex echinatior leaf-cutting ants primarily associate with actinomycetes of the genus Pseudonocardia. Colonies are inoculated with one of two vertically transmitted phylotypes (Ps1 or Ps2), and maintain the same phylotype over their lifetime. We performed a cross-fostering experiment to test whether co-adaptations between ants and bacterial phylotypes have evolved, and how this affects bacterial growth and ant prophylactic behavior after infection with Escovopsis. We show that Pseudonocardia readily colonized ants irrespective of their colony of origin, but that the Ps2 phylotype, which was previously shown to be better able to maintain its monocultural integrity after workers became foragers than Ps1, reached a higher final cover when grown on its native host than on alternative hosts. The frequencies of major grooming and weeding behaviors co-varied with symbiont/host combinations, showing that ant behavior also was affected when cuticular actinomycete phylotypes were swapped. These results show that the interactions between leaf-cutting ants and Pseudonocardia bear signatures of mutual co-adaptation within a single ant population.

  17. Visual cues for the retrieval of landmark memories by navigating wood ants.

    PubMed

    Harris, Robert A; Graham, Paul; Collett, Thomas S

    2007-01-23

    Even on short routes, ants can be guided by multiple visual memories. We investigate here the cues controlling memory retrieval as wood ants approach a one- or two-edged landmark to collect sucrose at a point along its base. In such tasks, ants store the desired retinal position of landmark edges at several points along their route. They guide subsequent trips by retrieving the appropriate memory and moving to bring the edges in the scene toward the stored positions. The apparent width of the landmark turns out to be a powerful cue for retrieving the desired retinal position of a landmark edge. Two other potential cues, the landmark's apparent height and the distance that the ant walks, have little effect on memory retrieval. A simple model encapsulates these conclusions and reproduces the ants' routes in several conditions. According to this model, the ant stores a look-up table. Each entry contains the apparent width of the landmark and the desired retinal position of vertical edges. The currently perceived width provides an index for retrieving the associated stored edge positions. The model accounts for the population behavior of ants and the idiosyncratic training routes of individual ants. Our results imply binding between the edge of a shape and its width and, further, imply that assessing the width of a shape does not depend on the presence of any particular local feature, such as a landmark edge. This property makes the ant's retrieval and guidance system relatively robust to edge occlusions.

  18. A mutualism without honeydew: what benefits for Melissotarsus emeryi ants and armored scale insects (Diaspididae)?

    PubMed

    Peeters, Christian; Foldi, Imre; Matile-Ferrero, Danièle; Fisher, Brian L

    2017-01-01

    Mutualisms between ants and sap-sucking insects generally involve clear benefits for both partners: the ants provide protection in exchange for honeydew. However, a single ant genus associates with armoured scale insects (Diaspididae) that do not excrete honeydew. We studied three colonies of Melissotarsus emeryi ants from two localities in Mozambique. Vast numbers of the diaspidid Morganella conspicua occupied galleries dug by the ants under the bark of living trees. Unlike free-living M. conspicua and other diaspidids, M. conspicua living with ants are known to lack shields, likely because they gain protection against enemies and desiccation. Nevertheless, we documented the occurrence of rare individuals with shields inside ant galleries, indicating that their glands continue to secrete wax and proteins as building material. This is likely to constitute a significant portion of the ants' diet, in addition to diaspidid exuviae and excretions from the Malpighian tubules. Indeed, Melissotarsus workers cannot walk outside the galleries due to modified middle legs, forcing them to obtain all nourishment within the tree. Melissotarsus founding queens, however, must locate a suitable host tree while flying, and acquire diaspidid crawlers. This mutualism involves ants that are highly specialised to chew through living wood, and diaspidids that can also live freely outside the bark. It is extremely widespread in Africa and Madagascar, recorded from 20 tree families, and harmful effects on plant hosts require rapid study.

  19. Crab regulation of cross-ecosystem resource transfer by marine foraging fire ants.

    PubMed

    Garcia, Erica A; Bertness, Mark D; Alberti, Juan; Silliman, Brian R

    2011-08-01

    Permeability of boundaries in biological systems is regulated by biotic and/or abiotic factors. Despite this knowledge, the role of biotic factors in regulating resource transfer across ecosystem boundaries has received little study. Additionally, little is known about how cross-ecosystem resource transfer affects source populations. We used experiments, observations and stable isotopes, to evaluate: (1) the proportion of intertidal-foraging black fire ant (Solenopsis richteri) diet derived from marine sources, (2) how black fire ant cross-ecosystem resource transfer is altered by the dominant bioengineer in the intertidal, a burrowing crab (Neohelice granulata), (3) the top-down impact of these terrestrial ants on a marine resource, and (4) the effect of marine resources on recipient black fire ants. We found that more than 85% of the black fire ant diet is derived from marine sources, the number of intertidal foraging ants doubles in the absence of crab burrows, and that ants cause a 50% reduction in intertidal polychaetes. Also, ant mound density is three times greater adjacent to marine systems. This study reveals that cross-ecosystem foraging terrestrial ants can clearly have strong impacts on marine resources. Furthermore, ecosystem engineers that modify and occupy habitat in these ecosystem boundaries can strongly regulate the degree of cross-ecosystem resource transfer and resultant top down impacts.

  20. Improving liquid bait programs for Argentine ant control: bait station density.

    PubMed

    Nelson, Erik H; Daane, Kent M

    2007-12-01

    Argentine ants, Linepithema humile (Mayr), have a positive effect on populations of mealybugs (Pseudococcus spp.) in California vineyards. Previous studies have shown reductions in both ant activity and mealybug numbers after liquid ant baits were deployed in vineyards at densities of 85-620 bait stations/ha. However, bait station densities may need to be <85 bait stations/ha before bait-based strategies for ant control are economically comparable to spray-based insecticide treatments-a condition that, if met, will encourage the commercial adoption of liquid baits for ant control. This research assessed the effectiveness of baits deployed at lower densities. Two field experiments were conducted in commercial vineyards. In experiment 1, baits were deployed at 54-225 bait stations/ha in 2005 and 2006. In experiment 2, baits were deployed at 34-205 bait stations/ha in 2006 only. In both experiments, ant activity and the density of mealybugs in grape fruit clusters at harvest time declined with increasing bait station density. In 2005 only, European fruit lecanium scale [Parthenolecanium corni (Bouché)] were also present in fruit clusters, and scale densities were negatively related to bait station density. The results indicate that the amount of ant and mealybug control achieved by an incremental increase in the number of bait stations per hectare is constant across a broad range of bait station densities. The results are discussed in the context of commercializing liquid ant baits to provide a more sustainable Argentine ant control strategy.

  1. Use of fluorescent ANTS to examine the BBB-permeability of polysaccharide

    PubMed Central

    Christopher, Kevin; Makani, Vishruti; Judy, Wesley; Lee, Erica; Chiaia, Nicolas; Kim, Dong Shik; Park, Joshua

    2015-01-01

    Recently, some polysaccharides showed therapeutic potentials for the treatment of neurodegenerative diseases while the most important property, their permeability to the blood brain barrier (BBB) that sheathes the brain and spinal cord, is not yet determined. The determination has been delayed by the difficulty in tracking a target polysaccharide among endogenous polysaccharides in animal. We developed an easy way to examine the BBB-permeability and, possibly, tissue distribution of a target polysaccharide in animal. We tagged a polysaccharide with fluorescent 8-aminonaphthalene-1,3,6-trisulfonic acid disodium salt (ANTS) for tracking. We also developed a simple method to separate ANTS-tagged polysaccharide from unconjugated free ANTS using 75% ethanol. After ANTS-polysaccharide was intra-nasally administered into animals, we could quantify the amounts of ANTS-polysaccharide in the brain and the serum by fluorocytometry. We could also separate free ANTS-polysaccharide from serum proteins using trichloroacetic acid (TCA) and 75% ethanol. Our method will help to track a polysaccharide in animal easily. • ANTS-labeling is less tedious than but as powerful as radiolabeling for tracking a target polysaccharide in animal. • Our simple method can separate structurally intact ANTS-polysaccharide from animal serum and tissues. • This method is good for the fluorometry-based measurement of ANTS-conjugated macromolecules in tissues. PMID:25914873

  2. Harnessing ant defence at fruits reduces bruchid seed predation in a symbiotic ant–plant mutualism

    PubMed Central

    Pringle, Elizabeth G.

    2014-01-01

    In horizontally transmitted mutualisms, mutualists disperse separately and reassemble in each generation with partners genetically unrelated to those in the previous generation. Because of this, there should be no selection on either partner to enhance the other's reproductive output directly. In symbiotic ant–plant mutualisms, myrmecophytic plants host defensive ant colonies, and ants defend the plants from herbivores. Plants and ants disperse separately, and, although ant defence can indirectly increase plant reproduction by reducing folivory, it is unclear whether ants can also directly increase plant reproduction by defending seeds. The neotropical tree Cordia alliodora hosts colonies of Azteca pittieri ants. The trees produce domatia where ants nest at stem nodes and also at the node between the peduncle and the rachides of the infloresence. Unlike the stem domatia, these reproductive domatia senesce after the tree fruits each year. In this study, I show that the tree's resident ant colony moves into these ephemeral reproductive domatia, where they tend honeydew-producing scale insects and patrol the nearby developing fruits. The presence of ants significantly reduced pre-dispersal seed predation by Amblycerus bruchid beetles, thereby directly increasing plant reproductive output. PMID:24807259

  3. Irresistible ants: exposure to novel toxic prey increases consumption over multiple temporal scales.

    PubMed

    Herr, Mark W; Robbins, Travis R; Centi, Alan; Thawley, Christopher J; Langkilde, Tracy

    2016-07-01

    As species become increasingly exposed to novel challenges, it is critical to understand how evolutionary (i.e., generational) and plastic (i.e., within lifetime) responses work together to determine a species' fate or predict its distribution. The introduction of non-native species imposes novel pressures on the native species that they encounter. Understanding how native species exposed to toxic or distasteful invaders change their feeding behavior can provide insight into their ability to cope with these novel threats as well as broader questions about the evolution of this behavior. We demonstrated that native eastern fence lizards do not avoid consuming invasive fire ants following repeated exposure to this toxic prey. Rather fence lizards increased their consumption of these ants following exposure on three different temporal scales. Lizards ate more fire ants when they were exposed to this toxic prey over successive days. Lizards consumed more fire ants if they had been exposed to fire ants as juveniles 6 months earlier. Finally, lizards from populations exposed to fire ants over multiple generations consumed more fire ants than those from fire ant-free areas. These results suggest that the potentially lethal consumption of fire ants may carry benefits resulting in selection for this behavior, and learning that persists long after initial exposure. Future research on the response of native predators to venomous prey over multiple temporal scales will be valuable in determining the long-term effects of invasion by these novel threats.

  4. Collective Response of Leaf-Cutting Ants to the Effects of Wind on Foraging Activity.

    PubMed

    Alma, Andrea Marina; Farji-Brener, Alejandro G; Elizalde, Luciana

    2016-11-01

    One advantage of sociality is to mitigate environmental restrictions through collective behavior. Here we document a colony-level response of leaf-cutting ants to wind, an environmental factor that impedes foraging. Given that larger ants adhere more strongly to the substrate, increasing forager size in windy conditions should reduce the negative effect of wind. We tested this idea for Acromyrmex lobicornis in windy regions of Patagonia. We examined (1) whether the fraction of larger ants versus smaller ants increased in windy conditions and (2) whether the effect of wind on the ants' movement was lower for larger ants. The size-frequency distribution of foragers was skewed more toward larger ants in nature under more windy conditions. Under windy conditions in the field, the mobility of smaller ants was more reduced than that of larger ants. The change toward larger foragers in windy conditions reduced the negative effect of wind by 32%, illustrating how a social organism can collectively mitigate the adverse effects of the environment.

  5. Effects of Invasive European Fire Ants (Myrmica rubra) on Herring Gull (Larus argentatus) Reproduction

    PubMed Central

    DeFisher, Luke E.; Bonter, David N.

    2013-01-01

    Various invasive ant species have negatively affected reproductive success in birds by disrupting nest site selection, incubation patterns, food supply, and by direct predation on nestlings. Impacts can be particularly severe when non-native ants colonize seabird nesting islands where thousands of birds may nest in high densities on the ground or in burrows or crevices. Here we report on the first documented effects of Myrmica rubra, the European fire ant, on the reproduction of birds in its non-native range. We documented herring gulls (Larus argentatus) on Appledore Island, Maine, engaging in more erratic incubation behaviors at nests infested by the ants. Newly-hatched chicks in some nests were swarmed by ants, leading to rapid chick death. Due to high overall rates of chick mortality, survival probabilities did not vary between nests with and without ant activity, however chick growth rates were slower at nests with ants than at ant-free nests. Ant infestation likely leads to longer-term fitness consequences because slower growth rates early in life may ultimately lead to lower post-fledging survival probabilities. PMID:23691168

  6. Invasive Fire Ants Reduce Reproductive Success and Alter the Reproductive Strategies of a Native Vertebrate Insectivore

    PubMed Central

    Ligon, Russell A.; Siefferman, Lynn; Hill, Geoffrey E.

    2011-01-01

    Background Introduced organisms can alter ecosystems by disrupting natural ecological relationships. For example, red imported fire ants (Solenopsis invicta) have disrupted native arthropod communities throughout much of their introduced range. By competing for many of the same food resources as insectivorous vertebrates, fire ants also have the potential to disrupt vertebrate communities. Methodology/Principal Findings To explore the effects of fire ants on a native insectivorous vertebrate, we compared the reproductive success and strategies of eastern bluebirds (Sialia sialis) inhabiting territories with different abundances of fire ants. We also created experimental dyads of adjacent territories comprised of one territory with artificially reduced fire ant abundance (treated) and one territory that was unmanipulated (control). We found that more bluebird young fledged from treated territories than from adjacent control territories. Fire ant abundance also explained significant variation in two measures of reproductive success across the study population: number of fledglings and hatching success of second clutches. Furthermore, the likelihood of bluebird parents re-nesting in the same territory was negatively influenced by the abundance of foraging fire ants, and parents nesting in territories with experimentally reduced abundances of fire ants produced male-biased broods relative to pairs in adjacent control territories. Conclusions/Significance Introduced fire ants altered both the reproductive success (number of fledglings, hatching success) and strategies (decision to renest, offspring sex-ratio) of eastern bluebirds. These results illustrate the negative effects that invasive species can have on native biota, including species from taxonomically distant groups. PMID:21799904

  7. Marking individual ants for behavioral sampling in a laboratory colony.

    PubMed

    Holbrook, C Tate

    2009-07-01

    Ant societies are tractable and malleable, two features that make them ideal models for probing the organization of complex biological systems. The ability to identify specific individuals while they function as part of a colony permits an integrative analysis of social complexity, including self-organizational processes (i.e., how individual-level properties and social interactions give rise to emergent, colony-level attributes such as division of labor and collective decision making). Effects of genotype, nutrition, and physiology on individual behavior and the organization of work also can be investigated in this manner, through correlative and manipulative approaches. Moreover, aspects of colony demography (e.g., colony size, and age and size distributions of workers) can be altered experimentally to examine colony development and regulatory mechanisms underlying colony homeostasis and resiliency. This protocol describes how to sample the behavior of ants living in a colony under laboratory conditions. Specifically, it outlines how to identify and observe individuals within a colony, an approach that can be used to quantify individual- and colony-level patterns of behavior. When a lower-resolution measure of overall group behavior is desired, individual identities might not be required. Given the diversity of ants and their study, this protocol provides a very general methodology; the details can be modified according to the body size, colony size, and ecology of the focal species, as well as to specific research aims. These basic techniques can also be extended to more advanced experimental designs such as manipulation of colony demography and hormone treatment.

  8. ANTS/SARA: Future Observation of Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Clark, P. E.; Rilee, M. L.; Curtis, S. A.; Cheung, C. Y.; Mumma, M. J.

    2004-05-01

    The Saturn Autonomous Ring Array (SARA) mission concept applies the Autonomous Nano-Technology Swarm (ANTS) architecture, a paradigm developed for exploration of high surface area and/or multi-body targets. ANTS architecture involves large numbers of tiny, highly autonomous, yet socially interactive, craft, in a small number of specialist classes. SARA will acquire in situ observations in the high gravity environment of Saturn's rings. The high potential for collision represents an insurmountable challenge for previous mission designs. Each ANTS nanocraft weighs approximately a kilogram, and thus requires gossamer structures for all subsystems. Individual specialists include Workers, the vast majority, that acquire scientific measurements, as well as Messenger/Rulers that provide communication and coordination. The high density distribution of particles combines with the high intensity gravity and magnetic field environment to produce dynamic plasmas. Plasma, particle, wave, and field detectors will take measurements from the edge of the ring plane to observe the result of particle interactions. Imagers and spectrome-ters would measure variations composition and dust/gas ratio among particles using a strategy for serial rendezvous with individual particles. The numbers and distances of these particles, as well as anticipated high attrition rate, re-quire hundreds of spacecraft to characterize thousands of particles and ring features over the course of the mission. The bimodal propulsion system would include a large solar sail carrier for transporting the swarm the long distance in low gravity between deployment site and the target, and a nuclear system for each craft for maneuvering in the high gravity regime of Saturn's rings.

  9. Social coercion of larval development in an ant species

    NASA Astrophysics Data System (ADS)

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  10. Ants Sow the Seeds of Global Diversification in Flowering Plants

    PubMed Central

    Lengyel, Szabolcs; Gove, Aaron D.; Latimer, Andrew M.; Majer, Jonathan D.; Dunn, Robert R.

    2009-01-01

    Background The extraordinary diversification of angiosperm plants in the Cretaceous and Tertiary periods has produced an estimated 250,000–300,000 living angiosperm species and has fundamentally altered terrestrial ecosystems. Interactions with animals as pollinators or seed dispersers have long been suspected as drivers of angiosperm diversification, yet empirical examples remain sparse or inconclusive. Seed dispersal by ants (myrmecochory) may drive diversification as it can reduce extinction by providing selective advantages to plants and can increase speciation by enhancing geographical isolation by extremely limited dispersal distances. Methodology/Principal Findings Using the most comprehensive sister-group comparison to date, we tested the hypothesis that myrmecochory leads to higher diversification rates in angiosperm plants. As predicted, diversification rates were substantially higher in ant-dispersed plants than in their non-myrmecochorous relatives. Data from 101 angiosperm lineages in 241 genera from all continents except Antarctica revealed that ant-dispersed lineages contained on average more than twice as many species as did their non-myrmecochorous sister groups. Contrasts in species diversity between sister groups demonstrated that diversification rates did not depend on seed dispersal mode in the sister group and were higher in myrmecochorous lineages in most biogeographic regions. Conclusions/Significance Myrmecochory, which has evolved independently at least 100 times in angiosperms and is estimated to be present in at least 77 families and 11 000 species, is a key evolutionary innovation and a globally important driver of plant diversity. Myrmecochory provides the best example to date for a consistent effect of any mutualism on large-scale diversification. PMID:19436714

  11. Social coercion of larval development in an ant species.

    PubMed

    Villalta, Irene; Amor, Fernando; Cerdá, Xim; Boulay, Raphaël

    2016-04-01

    Ants provide one of the best examples of the division of labor in animal societies. While the queens reproduce, workers generally refrain from laying eggs and dedicate themselves exclusively to domestic tasks. In many species, the small diploid larvae are bipotent and can develop either into workers or queens depending mostly on environmental cues. This generates a conflicting situation between the adults that tend to rear a majority of larvae into workers and the larvae whose individual interest may be to develop into reproductive queens. We tested the social regulation of larval caste fate in the fission-performing ant Aphaenogaster senilis. We first observed interactions between resident workers and queen- and worker-destined larvae in presence/absence of the queen. The results show that workers tend to specifically eliminate queen-destined larvae when the queen is present but not when she is absent or imprisoned in a small cage allowing for volatile pheromone exchanges. In addition, we found that the presence of already developed queen-destined larvae does not inhibit the development of younger still bipotent larvae into queens. Finally, we analyzed the cuticular hydrocarbon profiles of queen- and worker-destined larvae and found no significant quantitative or qualitative difference. Interestingly, the total amount of hydrocarbons on both larval castes is extremely low, which lends credence on the chemical insignificance hypothesis of larval ants. Overall, our results suggest that workers control larval development and police larvae that would develop into queens instead of workers. Such policing behavior is similar in many aspects to what is known of worker policing among adults.

  12. Origin and distribution of desert ants across the Gibraltar Straits.

    PubMed

    Villalta, Irene; Amor, Fernando; Galarza, Juan A; Dupont, Simon; Ortega, Patrocinio; Hefetz, Abraham; Dahbi, Abdallah; Cerdá, Xim; Boulay, Raphaël

    2018-01-01

    The creation of geographic barriers has long been suspected to contribute to the formation of new species. We investigated the phylogeography of desert ants in the western Mediterranean basin in order to elucidate their mode of diversification. These insects which have a low dispersal capacity are recently becoming important model systems in evolutionary studies. We conducted an extensive sampling of species belonging to the Cataglyphis albicans group in the Iberian Peninsula (IP) and the northern Morocco (North Africa; NA). We then combined genetic, chemical and morphological analyses. The results suggest the existence of at least three and five clades in the IP and NA, respectively, whose delineation partially encompass current taxonomic classification. The three Iberian clades are monophyletic, but their origin in NA is uncertain (79% and 22% for Bayesian and Maximum Likelihood support, respectively). The estimation of divergence time suggests that a speciation process was initiated after the last reopening of the Gibraltar Straits ≈5.33 Ma. In the IP, the clades are parapatric and their formation may have been triggered by the fragmentation of a large population during the Pleistocene due to extended periods of glaciation. This scenario is supported by demographic analyses pointing at a recent expansion of Iberian populations that contrasts with the progressive contraction of the NA clades. Niche modeling reveals that this area, governed by favorable climatic conditions for desert ants, has recently increased in the IP and decreased in NA. Altogether, our data points at geoclimatic events as major determinants of species formation in desert ants, reinforcing the role of allopatric speciation. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Dissecting ant recognition systems in the age of genomics.

    PubMed

    Tsutsui, Neil D

    2013-01-01

    Hamilton is probably best known for his seminal work demonstrating the role of kin selection in social evolution. His work made it clear that, for individuals to direct their altruistic behaviours towards appropriate recipients (kin), mechanisms must exist for kin recognition. In the social insects, colonies are typically comprised of kin, and colony recognition cues are used as proxies for kinship cues. Recent years have brought rapid advances in our understanding of the genetic and molecular mechanisms that are used for this process. Here, I review some of the most notable advances, particularly the contributions from recent ant genome sequences and molecular biology.

  14. Mutualistic ants contribute to tank-bromeliad nutrition.

    PubMed

    Leroy, Céline; Carrias, Jean-François; Corbara, Bruno; Pélozuelo, Laurent; Dézerald, Olivier; Brouard, Olivier; Dejean, Alain; Céréghino, Régis

    2013-09-01

    Epiphytism imposes physiological constraints resulting from the lack of access to the nutrient sources available to ground-rooted plants. A conspicuous adaptation in response to that lack is the phytotelm (plant-held waters) of tank-bromeliad species that are often nutrient-rich. Associations with terrestrial invertebrates also result in higher plant nutrient acquisition. Assuming that tank-bromeliads rely on reservoir-assisted nutrition, it was hypothesized that the dual association with mutualistic ants and the phytotelm food web provides greater nutritional benefits to the plant compared with those bromeliads involved in only one of these two associations. Quantitative (water volume, amount of fine particulate organic matter, predator/prey ratio, algal density) and qualitative variables (ant-association and photosynthetic pathways) were compared for eight tank- and one tankless-bromeliad morphospecies from French Guiana. An analysis was also made of which of these variables affect nitrogen acquisition (leaf N and δ(15)N). All variables were significantly different between tank-bromeliad species. Leaf N concentrations and leaf δ(15)N were both positively correlated with the presence of mutualistic ants. The amount of fine particulate organic matter and predator/prey ratio had a positive and negative effect on leaf δ(15)N, respectively. Water volume was positively correlated with leaf N concentration whereas algal density was negatively correlated. Finally, the photosynthetic pathway (C3 vs. CAM) was positively correlated with leaf N concentration with a slightly higher N concentration for C3-Tillandsioideae compared with CAM-Bromelioideae. The study suggests that some of the differences in N nutrition between bromeliad species can be explained by the presence of mutualistic ants. From a nutritional standpoint, it is more advantageous for a bromeliad to use myrmecotrophy via its roots than to use carnivory via its tank. The results highlight a gap in our

  15. Ants, eyelashes, and the 2015 Ig Nobel Prize in Physics

    NASA Astrophysics Data System (ADS)

    Hu, David

    2016-11-01

    The zoo can be a source of recreation and rich scientific investigation. In this lecture, I will give an overview of my recent research with animals at the Atlanta Zoo. We will talk about how to make ant hamburgers, how eyelashes reduce evaporation of your eyes by a factor of two, and why mammals urinate for the same duration of 21 seconds. Although animal-inspired research can sound trendy, it can lead the way toward potential future directions in fluid mechanics, including the dynamics of active materials, flow through hairy surfaces, and the physics of digestion and excretion.

  16. Occurrence of killer yeasts in leaf-cutting ant nests.

    PubMed

    Carreiro, S C; Pagnocca, F C; Bacci, M; Bueno, O C; Hebling, M J A; Middelhoven, W J

    2002-01-01

    Killer activity was screened in 99 yeast strains isolated from the nests of the leaf-cutting ant Atta sexdens against 6 standard sensitive strains, as well as against each other. Among this yeast community killer activity was widespread since 77 strains (78%) were able to kill or inhibit the growth of at least one standard strain or nest strain. Toxin production was observed in representatives of all the studied genera including Aureobasidium, Rhodotorula, Tremella and Trichosporon, whose killer activity has not yet been described.

  17. Mutualistic ants contribute to tank-bromeliad nutrition

    PubMed Central

    Leroy, Céline; Carrias, Jean-François; Corbara, Bruno; Pélozuelo, Laurent; Dézerald, Olivier; Brouard, Olivier; Dejean, Alain; Céréghino, Régis

    2013-01-01

    Background and Aims Epiphytism imposes physiological constraints resulting from the lack of access to the nutrient sources available to ground-rooted plants. A conspicuous adaptation in response to that lack is the phytotelm (plant-held waters) of tank-bromeliad species that are often nutrient-rich. Associations with terrestrial invertebrates also result in higher plant nutrient acquisition. Assuming that tank-bromeliads rely on reservoir-assisted nutrition, it was hypothesized that the dual association with mutualistic ants and the phytotelm food web provides greater nutritional benefits to the plant compared with those bromeliads involved in only one of these two associations. Methods Quantitative (water volume, amount of fine particulate organic matter, predator/prey ratio, algal density) and qualitative variables (ant-association and photosynthetic pathways) were compared for eight tank- and one tankless-bromeliad morphospecies from French Guiana. An analysis was also made of which of these variables affect nitrogen acquisition (leaf N and δ15N). Key Results All variables were significantly different between tank-bromeliad species. Leaf N concentrations and leaf δ15N were both positively correlated with the presence of mutualistic ants. The amount of fine particulate organic matter and predator/prey ratio had a positive and negative effect on leaf δ15N, respectively. Water volume was positively correlated with leaf N concentration whereas algal density was negatively correlated. Finally, the photosynthetic pathway (C3 vs. CAM) was positively correlated with leaf N concentration with a slightly higher N concentration for C3-Tillandsioideae compared with CAM-Bromelioideae. Conclusions The study suggests that some of the differences in N nutrition between bromeliad species can be explained by the presence of mutualistic ants. From a nutritional standpoint, it is more advantageous for a bromeliad to use myrmecotrophy via its roots than to use carnivory via its

  18. Spaceships, Rollerskates, and Kids Called Crazy.

    ERIC Educational Resources Information Center

    Jones, Ron

    1979-01-01

    Describes a summer school program where children in a mental hospital shared activities and learning experiences with "street kids"; presents some of the insights gained by members of both groups. (MAI)

  19. Sometimes You Must Act a Little Crazy.

    ERIC Educational Resources Information Center

    Batory, Joseph P.

    2003-01-01

    Retired Pennsylvania superintendent uses three fictional medical terms to describe negative attitudes and actions of certain governmental and corporate leaders toward public education: Perverted distortionism, quantification syndrome, and simple simonitis. Describes perverted distortionism, for example, as a disease of organizations and…

  20. Ant-caterpillar antagonism at the community level: interhabitat variation of tritrophic interactions in a neotropical savanna.

    PubMed

    Sendoya, Sebastián F; Oliveira, Paulo S

    2015-03-01

    Ant foraging on foliage can substantially affect how phytophagous insects use host plants and represents a high predation risk for caterpillars, which are important folivores. Ant-plant-herbivore interactions are especially pervasive in cerrado savanna due to continuous ant visitation to liquid food sources on foliage (extrafloral nectaries, insect honeydew). While searching for liquid rewards on plants, aggressive ants frequently attack or kill insect herbivores, decreasing their numbers. Because ants vary in diet and aggressiveness, their effect on herbivores also varies. Additionally, the differential occurrence of ant attractants (plant and insect exudates) on foliage produces variable levels of ant foraging within local floras and among localities. Here, we investigate how variation of ant communities and of traits among host plant species (presence or absence of ant attractants) can change the effect of carnivores (predatory ants) on herbivore communities (caterpillars) in a cerrado savanna landscape. We sampled caterpillars and foliage-foraging ants in four cerrado localities (70-460 km apart). We found that: (i) caterpillar infestation was negatively related with ant visitation to plants; (ii) this relationship depended on local ant abundance and species composition, and on local preference by ants for plants with liquid attractants; (iii) this was not related to local plant richness or plant size; (iv) the relationship between the presence of ant attractants and caterpillar abundance varied among sites from negative to neutral; and (v) caterpillars feeding on plants with ant attractants are more resistant to ant predation than those feeding on plants lacking attractants. Liquid food on foliage mediates host plant quality for lepidopterans by promoting generalized ant-caterpillar antagonism. Our study in cerrado shows that the negative effects of generalist predatory ants on herbivores are detectable at a community level, affecting patterns of abundance and

  1. Behavioral Strategies of Phorid Parasitoids and Responses of Their Hosts, the Leaf-Cutting Ants

    PubMed Central

    Elizalde, Luciana; Folgarait, Patricia Julia

    2012-01-01

    Host-searching and oviposition behaviors of parasitoids, and defensive responses of the hosts, are fundamental in shaping the ecology of host-parasitoid interactions. In order to uncover key behavioral features for the little known interactions between phorid parasitoids (Diptera: Phoridae) and their leaf-cutting ant hosts (Formicidae: Attini), host-related behavioral strategies (i.e., host searching and oviposition) for 13 phorid species, and host defensive responses (i.e., hitchhikers and particular body postures) for 11 ant species, were studied. Data was collected at 14 localities, one of them characterized by its high species richness for this host-parasitoid system. Phorid species showed both great variation and specificity in attacking behaviors. Some chose their hosts using either an ambush or an actively searching strategy, while some species attacked ants on different body parts, and specialized on ants performing different tasks, such as when ants were foraging, removing wastes to refuse piles, or repairing the nest. Combining all the behaviors recorded, most phorid species differed in performance in at least one, making it possible to recognize species in the field through their behavior. Phorid species that attacked hosts with greater activity levels showed overall higher attack rates, although there was no significant correlation between attack rates by most phorid species and ant activity outside the nest while parasitoids were attacking. The presence of phorids was a significant determinant for the presence of defensive behaviors by the ants. Although ant species varied in the incidence levels of these defensive behaviors, most ant species reacted against different phorids by utilizing similar behaviors, in contrast to what parasitoids do. General features of the observed phorid-ant interactions were parasitoid specialization and corresponding high interspecific variation in their behaviors, while their hosts showed generalized responses to attacks

  2. Acquisition and expression of memories of distance and direction in navigating wood ants.

    PubMed

    Fernandes, A Sofia D; Philippides, Andrew; Collett, Tom S; Niven, Jeremy E

    2015-11-01

    Wood ants, like other central place foragers, rely on route memories to guide them to and from a reliable food source. They use visual memories of the surrounding scene and probably compass information to control their direction. Do they also remember the length of their route and do they link memories of direction and distance? To answer these questions, we trained wood ant (Formica rufa) foragers in a channel to perform either a single short foraging route or two foraging routes in opposite directions. By shifting the starting position of the route within the channel, but keeping the direction and distance fixed, we tried to ensure that the ants would rely upon vector memories rather than visual memories to decide when to stop. The homeward memories that the ants formed were revealed by placing fed or unfed ants directly into a channel and assessing the direction and distance that they walked without prior performance of the food-ward leg of the journey. This procedure prevented the distance and direction walked being affected by a home vector derived from path integration. Ants that were unfed walked in the feeder direction. Fed ants walked in the opposite direction for a distance related to the separation between start and feeder. Vector memories of a return route can thus be primed by the ants' feeding state and expressed even when the ants have not performed the food-ward route. Tests on ants that have acquired two routes indicate that memories of the direction and distance of the return routes are linked, suggesting that they may be encoded by a common neural population within the ant brain. © 2015. Published by The Company of Biologists Ltd.

  3. Steep Decline and Cessation in Seed Dispersal by Myrmica rubra Ants

    PubMed Central

    2015-01-01

    Myrmecochorous diaspores bear a nutrient-rich appendage, the elaiosome, attractive to ant workers that retrieve them into the nest, detach the elaiosome and reject the seed intact. While this interaction is beneficial for the plant partner by ensuring its seed dispersal, elaiosome consumption has various effects −positive, negative or none − on ants’ demography and survival, depending on both the ant/plant species involved. In this context, the contribution of ants to seed dispersal strongly varies according to the ant/plant pairs considered. In this paper, we investigate whether the dynamics of myrmecochory also vary on a temporal scale, for a given pair of partners: Myrmica rubra ants and Viola odorata seeds. During their first encounter with seeds, ants collect all the diaspores and eat the majority of elaiosomes. Both the harvesting effort and the elaiosome consumption decline when seeds are offered on the next week and completely cease for the following weeks. This is related to a decrease in the number of foragers reaching the food source, as well as to a reduced probability for an ant contacting a seed to retrieve it. Seed retrieval is not reactivated after seven weeks without any encounter with V. odorata seeds. By contrast, naive ant colonies only fed with fruit flies do not show a decline of prey harvesting of which the speed of retrieval even increases over the successive weeks. Myrmecochory may thus be labile at the scale of a fruiting season due to the ability of ants to steeply tune and cease for several months the harvesting of these seemingly poorly rewarding items and to maintain cessation of seed exploitation. The present study emphasizes the importance of a long-lasting follow up of the myrmecochory process, to assess the stability of this ant-plant partnership and to identify mechanisms of adaptive harvesting in ants. PMID:26414161

  4. Ants contribute to pollination but not to reproduction in a rare calcareous grassland forb

    PubMed Central

    Bollmann, Felix; Saville, David; Riedel, Michael

    2018-01-01

    The number of plants pollinated by ants is surprisingly low given the abundance of ants and the fact that they are common visitors of angiosperms. Generally ants are considered as nectar robbers that do not provide pollination service. We studied the pollination system of the endangered dry grassland forb Euphorbia seguieriana and found two ant species to be the most frequent visitors of its flowers. Workers of Formica cunicularia carried five times more pollen than smaller Tapinoma erraticum individuals, but significantly more viable pollen was recovered from the latter. Overall, the viability of pollen on ant cuticles was significantly lower (p < 0.001)—presumably an antibiotic effect of the metapleural gland secretion. A marking experiment suggested that ants were unlikely to facilitate outcrossing as workers repeatedly returned to the same individual plant. In open pollinated plants and when access was given exclusively to flying insects, fruit set was nearly 100%. In plants visited by ants only, roughly one third of flowers set fruit, and almost none set fruit when all insects were excluded. The germination rate of seeds from flowers pollinated by flying insects was 31 ± 7% in contrast to 1 ± 1% resulting from ant pollination. We conclude that inbreeding depression may be responsible for the very low germination rate in ant pollinated flowers and that ants, although the most frequent visitors, play a negligible or even deleterious role in the reproduction of E. seguieriana. Our study reiterates the need to investigate plant fitness effects beyond seed set in order to confirm ant-plant mutualisms. PMID:29479496

  5. Leaf-cutting ant fungi produce cell wall degrading pectinase complexes reminiscent of phytopathogenic fungi.

    PubMed

    Schiøtt, Morten; Rogowska-Wrzesinska, Adelina; Roepstorff, Peter; Boomsma, Jacobus J

    2010-12-31

    Leaf-cutting (attine) ants use their own fecal material to manure fungus gardens, which consist of leaf material overgrown by hyphal threads of the basidiomycete fungus Leucocoprinus gongylophorus that lives in symbiosis with the ants. Previous studies have suggested that the fecal droplets contain proteins that are produced by the fungal symbiont to pass unharmed through the digestive system of the ants, so they can enhance new fungus garden growth. We tested this hypothesis by using proteomics methods to determine the gene sequences of fecal proteins in Acromyrmex echinatior leaf-cutting ants. Seven (21%) of the 33 identified proteins were pectinolytic enzymes that originated from the fungal symbiont and which were still active in the fecal droplets produced by the ants. We show that these enzymes are found in the fecal material only when the ants had access to fungus garden food, and we used quantitative polymerase chain reaction analysis to show that the expression of six of these enzyme genes was substantially upregulated in the fungal gongylidia. These unique structures serve as food for the ants and are produced only by the evolutionarily advanced garden symbionts of higher attine ants, but not by the fungi reared by the basal lineages of this ant clade. Pectinolytic enzymes produced in the gongylidia of the fungal symbiont are ingested but not digested by Acromyrmex leaf-cutting ants so that they end up in the fecal fluid and become mixed with new garden substrate. Substantial quantities of pectinolytic enzymes are typically found in pathogenic fungi that attack live plant tissue, where they are known to breach the cell walls to allow the fungal mycelium access to the cell contents. As the leaf-cutting ant symbionts are derived from fungal clades that decompose dead plant material, our results suggest that their pectinolytic enzymes represent secondarily evolved adaptations that are convergent to those normally found in phytopathogens.

  6. Efficient distribution of toy products using ant colony optimization algorithm

    NASA Astrophysics Data System (ADS)

    Hidayat, S.; Nurpraja, C. A.

    2017-12-01

    CV Atham Toys (CVAT) produces wooden toys and furniture, comprises 13 small and medium industries. CVAT always attempt to deliver customer orders on time but delivery costs are high. This is because of inadequate infrastructure such that delivery routes are long, car maintenance costs are high, while fuel subsidy by the government is still temporary. This study seeks to minimize the cost of product distribution based on the shortest route using one of five Ant Colony Optimization (ACO) algorithms to solve the Vehicle Routing Problem (VRP). This study concludes that the best of the five is the Ant Colony System (ACS) algorithm. The best route in 1st week gave a total distance of 124.11 km at a cost of Rp 66,703.75. The 2nd week route gave a total distance of 132.27 km at a cost of Rp 71,095.13. The 3rd week best route gave a total distance of 122.70 km with a cost of Rp 65,951.25. While the 4th week gave a total distance of 132.27 km at a cost of Rp 74,083.63. Prior to this study there was no effort to calculate these figures.

  7. A Culture-Sensitive Agent in Kirman's Ant Model

    NASA Astrophysics Data System (ADS)

    Chen, Shu-Heng; Liou, Wen-Ching; Chen, Ting-Yu

    The global financial crisis brought a serious collapse involving a "systemic" meltdown. Internet technology and globalization have increased the chances for interaction between countries and people. The global economy has become more complex than ever before. Mark Buchanan [12] indicated that agent-based computer models will prevent another financial crisis and has been particularly influential in contributing insights. There are two reasons why culture-sensitive agent on the financial market has become so important. Therefore, the aim of this article is to establish a culture-sensitive agent and forecast the process of change regarding herding behavior in the financial market. We based our study on the Kirman's Ant Model[4,5] and Hofstede's Natational Culture[11] to establish our culture-sensitive agent based model. Kirman's Ant Model is quite famous and describes financial market herding behavior from the expectations of the future of financial investors. Hofstede's cultural consequence used the staff of IBM in 72 different countries to understand the cultural difference. As a result, this paper focuses on one of the five dimensions of culture from Hofstede: individualism versus collectivism and creates a culture-sensitive agent and predicts the process of change regarding herding behavior in the financial market. To conclude, this study will be of importance in explaining the herding behavior with cultural factors, as well as in providing researchers with a clearer understanding of how herding beliefs of people about different cultures relate to their finance market strategies.

  8. Dual ant colony operational modal analysis parameter estimation method

    NASA Astrophysics Data System (ADS)

    Sitarz, Piotr; Powałka, Bartosz

    2018-01-01

    Operational Modal Analysis (OMA) is a common technique used to examine the dynamic properties of a system. Contrary to experimental modal analysis, the input signal is generated in object ambient environment. Operational modal analysis mainly aims at determining the number of pole pairs and at estimating modal parameters. Many methods are used for parameter identification. Some methods operate in time while others in frequency domain. The former use correlation functions, the latter - spectral density functions. However, while some methods require the user to select poles from a stabilisation diagram, others try to automate the selection process. Dual ant colony operational modal analysis parameter estimation method (DAC-OMA) presents a new approach to the problem, avoiding issues involved in the stabilisation diagram. The presented algorithm is fully automated. It uses deterministic methods to define the interval of estimated parameters, thus reducing the problem to optimisation task which is conducted with dedicated software based on ant colony optimisation algorithm. The combination of deterministic methods restricting parameter intervals and artificial intelligence yields very good results, also for closely spaced modes and significantly varied mode shapes within one measurement point.

  9. Hybridogenesis through thelytokous parthenogenesis in two Cataglyphis desert ants.

    PubMed

    Eyer, P A; Leniaud, L; Darras, H; Aron, S

    2013-02-01

    Hybridogenesis is a sexual reproductive system, whereby parents from different genetic origin hybridize. Both the maternal and paternal genomes are expressed in somatic tissues, but the paternal genome is systematically excluded from the germ line, which is therefore purely maternal. Recently, a unique case of hybridogenesis at a social level was reported in the desert ant Cataglyphis hispanica. All workers are sexually produced hybridogens, whereas sexual forms (new queens and males) are produced by queens through parthenogenesis. Thus, only maternal genes are perpetuated across generations. Here, we show that such an unusual reproductive strategy also evolved in two other species of Cataglyphis belonging to the same phylogenetic group, Cataglyphis velox and Cataglyphis mauritanica. In both species, queens mate exclusively with males originating from a different genetic lineage than their own to produce hybrid workers, while they use parthenogenesis to produce the male and female reproductive castes. In contrast to single-queen colonies of C. hispanica, colonies of C. velox and C. mauritanica are headed by several queens. Most queens within colonies share the same multilocus genotype and never transmit their mates' alleles to the reproductive castes. Social hybridogenesis in the desert ants has direct consequences on the genetic variability of populations and on caste determination. We also discuss the maintenance of this reproductive strategy within the genus Cataglyphis. © 2012 Blackwell Publishing Ltd.

  10. Thelytokous Parthenogenesis in the Ant Myrmecina nipponica (Hymenoptera: Formicidae).

    PubMed

    Masuko, Keiichi

    2014-09-01

    Myrmecina nipponica Wheeler is a terrestrial ant nesting chiefly in the soil in forest. It is a specialized predator of oribatid mites, but also scavenges on a broad spectrum of other arthropods. In the studied population at Cape Manazuru in central Japan, M. nipponica colonies are typically monogynous, and previous dissections of queens suggested that these individuals were not inseminated, thus suggesting these ants can reproduce via thelytokous parthenogenesis. To test for thelytokous parthenogenesis in M. nipponica the spermathecae of queens (dealate gynes) from worker-containing colonies were histologically examined in detail. All specimens examined (n=5) had no spermatozoa in the spermatheca. In addition, a total of four colony-founding queens were reared in isolation in the laboratory to test whether non-inseminated females were capable of egg laying and to test whether female offspring emerged from this brood. In all of four culture replicates, only new workers were produced from the eggs those queens had laid and male offspring was absent. After the breeding experiment, the queens' spermathecae were histologically examined and no sperm were detected in their spermathecae. These results reveal that M. nipponica queens of the Manazuru population are capable of producing female offspring thelytokously. Sexual reproduction by typical gynes and also by intermorphs has been known from other local populations of M. nipponica; therefore, this species shows geographical polymorphism in sexuality.

  11. Resource redistribution in polydomous ant nest networks: local or global?

    PubMed Central

    Franks, Daniel W.; Robinson, Elva J.H.

    2014-01-01

    An important problem facing organisms in a heterogeneous environment is how to redistribute resources to where they are required. This is particularly complex in social insect societies as resources have to be moved both from the environment into the nest and between individuals within the nest. Polydomous ant colonies are split between multiple spatially separated, but socially connected, nests. Whether, and how, resources are redistributed between nests in polydomous colonies is unknown. We analyzed the nest networks of the facultatively polydomous wood ant Formica lugubris. Our results indicate that resource redistribution in polydomous F. lugubris colonies is organized at the local level between neighboring nests and not at the colony level. We found that internest trails connecting nests that differed more in their amount of foraging were stronger than trails between nests with more equal foraging activity. This indicates that resources are being exchanged directly from nests with a foraging excess to nests that require resources. In contrast, we found no significant relationships between nest properties, such as size and amount of foraging, and network measures such as centrality and connectedness. This indicates an absence of a colony-level resource exchange. This is a clear example of a complex behavior emerging as a result of local interactions between parts of a system. PMID:25214755

  12. Fitness costs of worker specialization for ant societies

    PubMed Central

    Jongepier, Evelien; Foitzik, Susanne

    2016-01-01

    Division of labour is of fundamental importance for the success of societies, yet little is known about how individual specialization affects the fitness of the group as a whole. While specialized workers may be more efficient in the tasks they perform than generalists, they may also lack the flexibility to respond to rapid shifts in task needs. Such rigidity could impose fitness costs when societies face dynamic and unpredictable events, such as an attack by socially parasitic slavemakers. Here, we experimentally assess the colony-level fitness consequences of behavioural specialization in Temnothorax longispinosus ants that are attacked by the slavemaker ant T. americanus. We manipulated the social organization of 102 T. longispinosus colonies, based on the behavioural responses of all 3842 workers. We find that strict specialization is disadvantageous for a colony's annual reproduction and growth during slave raids. These fitness costs may favour generalist strategies in dynamic environments, as we also demonstrate that societies exposed to slavemakers in the field show a lower degree of specialization than those originating from slavemaker-free populations. Our findings provide an explanation for the ubiquity of generalists and highlight their importance for the flexibility and functional robustness of entire societies. PMID:26763706

  13. Rationality in collective decision-making by ant colonies

    PubMed Central

    Edwards, Susan C.; Pratt, Stephen C.

    2009-01-01

    Economic models of animal behaviour assume that decision-makers are rational, meaning that they assess options according to intrinsic fitness value and not by comparison with available alternatives. This expectation is frequently violated, but the significance of irrational behaviour remains controversial. One possibility is that irrationality arises from cognitive constraints that necessitate short cuts like comparative evaluation. If so, the study of whether and when irrationality occurs can illuminate cognitive mechanisms. We applied this logic in a novel setting: the collective decisions of insect societies. We tested for irrationality in colonies of Temnothorax ants choosing between two nest sites that varied in multiple attributes, such that neither site was clearly superior. In similar situations, individual animals show irrational changes in preference when a third relatively unattractive option is introduced. In contrast, we found no such effect in colonies. We suggest that immunity to irrationality in this case may result from the ants’ decentralized decision mechanism. A colony's choice does not depend on site comparison by individuals, but instead self-organizes from the interactions of multiple ants, most of which are aware of only a single site. This strategy may filter out comparative effects, preventing systematic errors that would otherwise arise from the cognitive limitations of individuals. PMID:19625319

  14. Sex ratio and Wolbachia infection in the ant Formica exsecta.

    PubMed

    Keller, L; Liautard, C; Reuter, M; Brown, W D; Sundström, L; Chapuisat, M

    2001-08-01

    Sex allocation data in social Hymenoptera provide some of the best tests of kin selection, parent-offspring conflict and sex ratio theories. However, these studies critically depend on controlling for confounding ecological factors and on identifying all parties that potentially manipulate colony sex ratio. It has been suggested that maternally inherited parasites may influence sex allocation in social Hymenoptera. If the parasites can influence sex allocation, infected colonies are predicted to invest more resources in females than non-infected colonies, because the parasites are transmitted through females but not males. Prime candidates for such sex ratio manipulation are Wolbachia, because these cytoplasmically transmitted bacteria have been shown to affect the sex ratio of host arthropods by cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. In this study, we tested whether Wolbachia infection is associated with colony sex ratio in two populations of the ant Formica exsecta that have been the subject of extensive sex ratio studies. In these populations colonies specialize in the production of one sex or the other. We found that almost all F. exsecta colonies in both populations are infected with Wolbachia. However, in neither population did we find a significant association in the predicted direction between the prevalence of Wolbachia and colony sex ratio. In particular, colonies with a higher proportion of infected workers did not produce more females. Hence, we conclude that Wolbachia does not seem to alter the sex ratio of its hosts as a means to increase transmission rate in these two populations of ants.

  15. Dioecy and the evolution of sex ratios in ants

    PubMed Central

    Wiernasz, Diane C.; Cole, Blaine J.

    2009-01-01

    Split sex ratios, when some colonies produce only male and others only female reproductives, is a common feature of social insects, especially ants. The most widely accepted explanation for split sex ratios was proposed by Boomsma and Grafen, and is driven by conflicts of interest among colonies that vary in relatedness. The predictions of the Boomsma–Grafen model have been confirmed in many cases, but contradicted in several others. We adapt a model for the evolution of dioecy in plants to make predictions about the evolution of split sex ratios in social insects. Reproductive specialization results from the instability of the evolutionarily stable strategy (ESS) sex ratio, and is independent of variation in relatedness. We test predictions of the model with data from a long-term study of harvester ants, and show that it correctly predicts the intermediate sex ratios we observe in our study species. The dioecy model provides a comprehensive framework for sex allocation that is based on the pay-offs to the colony via production of males and females, and is independent of the genetic variation among colonies. However, in populations where the conditions for the Boomsma–Grafen model hold, kin selection will still lead to an association between sex ratio and relatedness. PMID:19324757

  16. Dynamics of sperm transfer in the ant Leptothorax gredleri

    NASA Astrophysics Data System (ADS)

    Oppelt, Angelika; Heinze, Jürgen

    2007-09-01

    Mating tactics differ remarkably between and within species of social Hymenoptera (bees, wasps, ants) concerning, e.g., mating frequencies, sperm competition, and the degree of male sperm limitation. Although social Hymenoptera might, therefore, potentially be ideal model systems for testing sexual selection theory, the dynamics of mating and sperm transfer have rarely been studied in species other than social bees, and basic information needed to draw conclusions about possible sperm competition and female choice is lacking. We investigated sperm transfer in the ant Leptothorax gredleri, a species in which female sexuals attract males by “female calling.” The analysis of 38 female sexuals fixed immediately or up to 7 days after copulation with a single male each revealed that the sperm is transferred into the female bursa copulatrix embedded in a gelatinous mass, presumably a spermatophore. Sperm cells rapidly start to migrate from the tip of the spermatophore towards the spermatheca, but transfer is drastically slowed down by an extreme constriction of the spermathecal duct, through which sperm cells have to pass virtually one by one. This results in the spermatheca being filled only between one and several hours after mating. During this time, the posterior part of the spermatophore seals the junction between bursa copulatrix and spermathecal duct and prevents sperm loss. The prolonged duration of sperm transfer might allow female sexuals to chose between ejaculates and explain previously reported patterns of single paternity of the offspring of multiply mated queens.

  17. Social interactions promote adaptive resource defense in ants

    PubMed Central

    Heeb, Eva Linda; Neupert, Stefanie

    2017-01-01

    Social insects vigorously defend their nests against con- and heterospecific competitors. Collective defense is also seen at highly profitable food sources. Aggressive responses are elicited or promoted by several means of communication, e.g. alarm pheromones and other chemical markings. In this study, we demonstrate that the social environment and interactions among colony members (nestmates) modulates the propensity to engage in aggressive behavior and therefore plays an important role in allocating workers to a defense task. We kept Formica rufa workers in groups or isolated for different time spans and then tested their aggressiveness in one-on-one encounters with other ants. In groups of more than 20 workers that are freely interacting, individuals are aggressive in one-on-one encounters with non-nestmates, whereas aggressiveness of isolated workers decreases with increasing isolation time. We conclude that ants foraging collectively and interacting frequently, e.g. along foraging trails and at profitable food sources, remain in a social context and thereby maintain high aggressiveness against potential competitors. Our results suggest that the nestmate recognition system can be utilized at remote sites for an adaptive and flexible tuning of the response against competitors. PMID:28910322

  18. The nest architecture of the ant Odontomachus brunneus.

    PubMed

    Cerquera, Lina M; Tschinkel, Walter R

    2010-01-01

    The architecture of the subterranean nests of the ant Odontomachus brunneus (Patton) (Hymenoptera: Formicidae) was studied by means of casts with dental plaster or molten metal. The entombed ants were later recovered by dissolution of plaster casts in hot running water. O. brunneus excavates simple nests, each consisting of a single, vertical shaft connecting more or less horizontal, simple chambers. Nests contained between 11 and 177 workers, from 2 to 17 chambers, and 28 to 340 cm(2) of chamber floor space and reached a maximum depth of 18 to 184 cm. All components of nest size increased simultaneously during nest enlargement, number of chambers, mean chamber size, and nest depth, making the nest shape (proportions) relatively size-independent. Regardless of nest size, all nests had approximately 2 cm(2) of chamber floor space per worker. Chambers were closer together near the top and the bottom of the nest than in the middle, and total chamber area was greater near the bottom. Colonies occasionally incorporated cavities made by other animals into their nests.

  19. Predicting future coexistence in a North American ant community

    PubMed Central

    Bewick, Sharon; Stuble, Katharine L; Lessard, Jean-Phillipe; Dunn, Robert R; Adler, Frederick R; Sanders, Nathan J

    2014-01-01

    Global climate change will remodel ecological communities worldwide. However, as a consequence of biotic interactions, communities may respond to climate change in idiosyncratic ways. This makes predictive models that incorporate biotic interactions necessary. We show how such models can be constructed based on empirical studies in combination with predictions or assumptions regarding the abiotic consequences of climate change. Specifically, we consider a well-studied ant community in North America. First, we use historical data to parameterize a basic model for species coexistence. Using this model, we determine the importance of various factors, including thermal niches, food discovery rates, and food removal rates, to historical species coexistence. We then extend the model to predict how the community will restructure in response to several climate-related changes, such as increased temperature, shifts in species phenology, and altered resource availability. Interestingly, our mechanistic model suggests that increased temperature and shifts in species phenology can have contrasting effects. Nevertheless, for almost all scenarios considered, we find that the most subordinate ant species suffers most as a result of climate change. More generally, our analysis shows that community composition can respond to climate warming in nonintuitive ways. For example, in the context of a community, it is not necessarily the most heat-sensitive species that are most at risk. Our results demonstrate how models that account for niche partitioning and interspecific trade-offs among species can be used to predict the likely idiosyncratic responses of local communities to climate change. PMID:24963378

  20. Genetic polymorphism in leaf-cutting ants is phenotypically plastic.

    PubMed

    Hughes, William O H; Boomsma, Jacobus J

    2007-07-07

    Advanced societies owe their success to an efficient division of labour that, in some social insects, is based on specialized worker phenotypes. The system of caste determination in such species is therefore critical. Here, we examine in a leaf-cutting ant (Acromyrmex echinatior) how a recently discovered genetic influence on caste determination interacts with the social environment. By removing most of one phenotype (large workers; LW) from test colonies, we increased the stimulus for larvae to develop into this caste, while for control colonies we removed a representative sample of all workers so that the stimulus was unchanged. We established the relative tendencies of genotypes to develop into LW by genotyping workers before and after the manipulation. In the control colonies, genotypes were similarly represented in the large worker caste before and after worker removal. In the test colonies, however, this relationship was significantly weaker, demonstrating that the change in environmental stimuli had altered the caste propensity of at least some genotypes. The results indicate that the genetic influence on worker caste determination acts via genotypes differing in their response thresholds to environmental cues and can be conceptualized as a set of overlapping reaction norms. A plastic genetic influence on division of labour has thus evolved convergently in two distantly related polyandrous taxa, the leaf-cutting ants and the honeybees, suggesting that it may be a common, potentially adaptive, property of complex, genetically diverse societies.