scholarly journals Impact of soil contamination on the growth and shape of ant nests

2018 ◽  
Vol 5 (7) ◽  
pp. 180267 ◽  
Author(s):  
Jean-Baptiste Leclerc ◽  
Jennifer Pinto Silva ◽  
Claire Detrain
Keyword(s):  
Small Groups ◽  
Fungal Spores ◽  
Key Factors ◽  
Myrmica Rubra ◽  
Ant Colonies ◽  
Immune Priming ◽  
Insect Societies ◽  
Nesting Sites ◽  
High Consistency ◽  
Lethal Doses

As entomopathogens are detrimental to the development or even survival of insect societies, ant colonies should avoid digging into a substrate that is contaminated by fungal spores. Here, we test the hypotheses that Myrmica rubra ant workers (i) detect and avoid fungus-infected substrates and (ii) excavate nest patterns that minimize their exposure to entomopathogenic spores. Small groups of M. rubra workers were allowed to dig their nest in a two-dimensional sand plate of which one half of the substrate contained fungal spores of Metarhizium brunneum , while the other half was spore-free. We found that the overall digging dynamics of M. rubra nests was not altered by the presence of fungus spores. By contrast, the shape of the excavated areas markedly differed: control nests showed rather isotropic patterns, whereas nests that were partially dug into a fungus-contaminated substrate markedly deviated from a circular shape. This demonstrates that the sanitary risks associated with a digging substrate are key factors in nest morphogenesis. We also found that M. rubra colonies were able to discriminate between the two substrates (fungus-infected or not). Furthermore, some colonies unexpectedly showed a high consistency in excavating mainly the infected substrate. This seemingly suboptimal preference for a contaminated soil suggests that non-lethal doses of fungal spores could help ant colonies to trigger ‘immune priming’. The presence of fungi may also indicate favourable ecological conditions, such as humid and humus-rich soil, that ants use as a cue for selecting suitable nesting sites.

scholarly journals Prophylactic Avoidance of Hazardous Prey by the Ant Host Myrmica rubra

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 444
Author(s):  
Hugo Pereira ◽  
Claire Detrain
Keyword(s):  
Entomopathogenic Fungi ◽  
Fungal Spores ◽  
Fungal Contamination ◽  
Myrmica Rubra ◽  
Ant Colonies ◽  
Metarhizium Brunneum ◽  
Functional Value ◽  
Prey Discrimination ◽  
Pathogen Avoidance ◽  
Infectious Potential

Ants are the hosts of many microorganisms, including pathogens that are incidentally brought inside the nest by foragers. This is particularly true for scavenging species, which collect hazardous food such as dead insects. Foragers limit sanitary risks by not retrieving highly infectious prey releasing entomopathogenic fungal spores. This study investigates whether similar prophylactic strategies are also developed for food associated with weak or delayed risks of fungal contamination. We compared, in Myrmica rubra ant colonies, the retrieval dynamics of dead flies that were (1) conidia-free, (2) covered with a low amount of Metarhizium brunneum entomopathogenic conidia or (3) recently fungus-killed but not yet sporulating. Foragers mostly avoided fungus-killed prey and delayed the retrieval of conidia-covered flies. A second sanitary filter occurred inside the nest through a careful inspection of the retrieved prey. Ultimately, ants mostly consumed conidia-free and conidia-covered flies, but they relocated and discarded all fungus-killed prey outside of the nest. Our study confirms that, as a host of generalist entomopathogenic fungi, Myrmica rubra ants have developed a prophylactic avoidance and a differential management of prey depending on their infectious potential. We discuss the functional value as well as the possible cues underlying pathogen avoidance and prey discrimination in ants.

scholarly journals 3D mapping of disease in ant societies reveals a strategy of a specialized parasite

2014 ◽  
Author(s):  
Raquel G Loreto ◽  
Simon L Elliot ◽  
Mayara LR Freitas ◽  
Thairine M Pereira ◽  
David P Hughes
Keyword(s):  
Disease Spread ◽  
Social Immunity ◽  
Ant Colonies ◽  
Effective Strategies ◽  
Insect Societies ◽  
The Social ◽  
Disease Free ◽  
Ophiocordyceps Unilateralis ◽  
Disease Present

Despite the widely held position that the social insects have evolved effective ways to limit infectious disease spread, many pathogens and parasites do attack insect societies. Maintaining a disease-free nest environment is an important evolutionary feature, but since workers have to leave the nest to forage they are routinely exposed to disease. Here we show that despite effective social immunity, in which workers act collectively to reduce disease inside the nest, 100% of studied ant colonies of Camponotus rufipes in a Brazilian Rainforest were infected by the specialized fungal parasite Ophiocordyceps unilateralis s.l. Not only is disease present for all colonies but long-term dynamics over 20 months revealed disease is a permanent feature. Using 3D maps, we showed the parasite optimizes its transmission by controlling workers’ behavior to die on the doorstep of the colony, where susceptible foragers are predictable in time and space. Therefore, despite social immunity, specialized diseases of ants have evolved effective strategies to exploit insect societies.

Niche opportunity and ant invasion: the case of Wasmannia auropunctata in a New Caledonian rain forest

2005 ◽  
Vol 21 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Julien Le Breton ◽  
Hervé Jourdan ◽  
Jean Chazeau ◽  
Jérôme Orivel ◽  
Alain Dejean
Keyword(s):  
Resource Use ◽  
Rain Forest ◽  
Biotic Resistance ◽  
Fire Ant ◽  
Food Sources ◽  
Ant Colonies ◽  
Wasmannia Auropunctata ◽  
Nesting Sites ◽  
Island Communities ◽  
Little Fire Ant

Due to the unbalanced distribution of their fauna and flora, which leads to the creation of a niche opportunities, it is generally accepted that island communities offer weak biotic resistance to biological invasion. In order to empirically test this statement, we compared resource use by ants in the understorey of an undisturbed New Caledonian rain forest recently invaded by the little fire ant, Wasmannia auropunctata. We tested the exploitation of: (1) food sources by placing baits on all trees with trunks greater than 5 cm in diameter; and (2) nesting sites on two tree species likely to shelter ant colonies. In non-invaded areas, the native ants occupied only 44.6% of the baits after 2 h of exposure, while in invaded areas all the baits were occupied by numerous W. auropunctata workers. Similarly, in non-invaded areas only 48.9% of Meryta coriacea (Araliaceae) trees and 64.5% of Basselinia pancheri (Arecaceae) sheltered ants, while in invaded areas W. auropunctata nested in 92.6–98.3% of these trees. Also, workers attended native Margarodidae (Hemiptera) for which they promoted the development of populations significantly larger than those attended by native ants. Thus native ants appear unable to efficiently exploit and defend several of the available food sources and nesting sites, providing a niche opportunity for an invader like W. auropunctata.

scholarly journals Pathogen avoidance and prey discrimination in ants

2020 ◽  
Vol 7 (2) ◽  
pp. 191705 ◽  
Author(s):  
Hugo Pereira ◽  
Claire Detrain
Keyword(s):  
Fungal Infection ◽  
Foraging Behaviour ◽  
Chemical Cues ◽  
Myrmica Rubra ◽  
Physico Chemical ◽  
Insect Societies ◽  
Binary Choices ◽  
Prey Discrimination ◽  
Pathogen Avoidance ◽  
Infected Prey

Insect societies have developed sanitary strategies, one of which is the avoidance of infectious food resources as a primary line of defence. Using binary choices, we investigated whether Myrmica rubra ants can identify prey that has been artificially infected with the entomopathogenic fungus, Metarhizium brunneum . We compared the ants' foraging behaviour towards infected prey at three different stages of fungus development : (i) prey covered with fungal conidia, (ii) prey freshly killed by the fungus and (iii) sporulating prey. Most foragers retrieved a corpse covered with a high number of spores but they consistently avoided a sporulating prey and collected less prey that had recently died from fungal infection. Furthermore, ant responses were highly variable, with some individuals retrieving the first prey they encountered while others inspected both available prey before making a decision. Workers were not repelled by the simple presence of fungal conidia but nevertheless, they avoided retrieving cadavers at later stages of fungal infection. We discuss how these different avoidance responses could be related to: differences in the ants’ perceptive abilities; physico-chemical cues characterizing fungus-infected prey or in the existence of physiological or behavioural defences that limit sanitary risks associated with potentially contaminated resources.

scholarly journals Towards a general life-history model of the superorganism: predicting the survival, growth and reproduction of ant societies

2012 ◽  
Vol 8 (6) ◽  
pp. 1059-1062 ◽  
Author(s):  
Jonathan Z. Shik ◽  
Chen Hou ◽  
Adam Kay ◽  
Michael Kaspari ◽  
James F. Gillooly
Keyword(s):  
Life History ◽  
Terrestrial Ecosystems ◽  
The Body ◽  
Ant Colonies ◽  
Insect Societies ◽  
Model Predictions ◽  
Body Sizes ◽  
Survival And Reproduction ◽  
Growth And Reproduction ◽  
Colony Level

Social insect societies dominate many terrestrial ecosystems across the planet. Colony members cooperate to capture and use resources to maximize survival and reproduction. Yet, when compared with solitary organisms, we understand relatively little about the factors responsible for differences in the rates of survival, growth and reproduction among colonies. To explain these differences, we present a mathematical model that predicts these three rates for ant colonies based on the body sizes and metabolic rates of colony members. Specifically, the model predicts that smaller colonies tend to use more energy per gram of biomass, live faster and die younger. Model predictions are supported with data from whole colonies for a diversity of species, with much of the variation in colony-level life history explained based on physiological traits of individual ants. The theory and data presented here provide a first step towards a more general theory of colony life history that applies across species and environments.

scholarly journals Nest Entrances, Spatial Fidelity, and Foraging Patterns in the Red Ant Myrmica rubra: A Field and Theoretical Study

Insects ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 317 ◽  
Author(s):  
Marine Lehue ◽  
Claire Detrain ◽  
Bertrand Collignon
Keyword(s):  
Spatial Distribution ◽  
Social Insects ◽  
Theoretical Study ◽  
High Fidelity ◽  
Nest Architecture ◽  
Myrmica Rubra ◽  
Foraging Patterns ◽  
Ant Colonies ◽  
Agent Model ◽  
Multi Agent

The nest architecture of social insects deeply impacts the spatial distribution of nestmates their interactions, information exchanges and collective responses. In particular, the number of nest entrances can influence the interactions taking place beyond the nest boundaries and the emergence of collective structures like foraging trails. Here, we investigated in the field how the number of nest entrances impacted the foraging dynamics of Myrmica rubra ant colonies. We located the nest entrances where recruitment occurred towards sugar feeders placed in their surroundings. The nests showed one or multiple entrance(s) aggregated in clusters spaced by at least 15 cm. Foragers from colonies with two clusters of entrances were distributed more homogeneously among the feeders than those of colonies with one cluster. In addition, foragers always returned to the first discovered feeder and demonstrated a high fidelity to their original entrance. Finally, a multi-agent model highlighted that additional entrances and clusters of entrances delayed the mobilisation of workers but favoured the simultaneous exploitation of several sources, which was further enhanced by the spatial fidelity of foragers. Multiple nest entrances seem to be a way for medium-sized colonies to benefit from advantages conferred by polydomy while avoiding associated costs to maintain social cohesion.

scholarly journals Presence of Pathogen-killed Larvae Influences Nesting Behavior of the Alfalfa Leafcutting Bee (Hymenoptera: Megachilidae)

2021 ◽  
Author(s):  
Ellen G Klinger ◽  
Dennis L Welker ◽  
Rosalind R James
Keyword(s):  
Natural Environment ◽  
Fungal Spores ◽  
Field Studies ◽  
Behavioral Changes ◽  
Nesting Behavior ◽  
Megachile Rotundata ◽  
Fungal Exposure ◽  
Nesting Sites ◽  
Alfalfa Seed ◽  
Nesting Patterns

Abstract The alfalfa leafcutting bee (Megachile rotundata (Fabricius)), a commercial pollinator used for alfalfa seed production, is susceptible to chalkbrood disease via ingested fungal spores. Diseases of insects can elicit behavioral changes in their hosts, but there are no recorded behaviors of alfalfa leafcutting bees in response to this fungal exposure. We conducted field studies to determine whether bees in pathogen-dense environments altered their nesting patterns, specifically if bees exposed to fungal spores produced higher numbers of nest cells and whether the proportions of nest cells that failed as eggs or small larvae (a state known as ‘pollen ball’) were greater. We found that our control bees, nontreated bees which were not exposed to chalkbrood spores other than those in the natural environment, had the highest proportion of pollen ball cells. Bees experimentally exposed to infective spores created the lowest number of nests and the fewest cells. Bees experimentally exposed to heat killed noninfective spores produced the greatest number of nests and cells overall and the greatest number of healthy progeny. We conclude that there are underlying behaviors that are elicited in response to the presence of chalkbrood spores that reduce the proportion of failed nest cells (grooming) and increase retention of bees at nesting sites (delay of bee emergence). Through further study of these behaviors, bee managers can potentially increase the productivity of their bee populations.

scholarly journals Colony size and brood investment of Myrmica rubra ant colonies in habitats invaded by goldenrods

2018 ◽  
Vol 65 (2) ◽  
pp. 275-280 ◽  
Author(s):  
I. M. Grześ ◽  
P. Ślipiński ◽  
H. Babik ◽  
D. Moroń ◽  
B. Walter ◽  
...  
Keyword(s):  
Colony Size ◽  
Myrmica Rubra ◽  
Ant Colonies

scholarly journals Automated tracking and analysis of ant trajectories shows variation in forager exploration

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Natalie Imirzian ◽  
Yizhe Zhang ◽  
Christoph Kurze ◽  
Raquel G. Loreto ◽  
Danny Z. Chen ◽  
...  
Keyword(s):  
Fungal Spores ◽  
Resource Discovery ◽  
Ant Colonies ◽  
Walking Behavior ◽  
Video Footage ◽  
Carpenter Ant ◽  
Human Labor ◽  
Ecological Success ◽  
Resource Conditions ◽  
Straight Lines

Abstract Determining how ant colonies optimize foraging while mitigating pathogen and predator risks provides insight into how the ants have achieved ecological success. Ants must respond to changing resource conditions, but exploration comes at a cost of higher potential exposure to threats. Fungal infected cadavers surround the main foraging trails of the carpenter ant Camponotus rufipes, offering a system to study how foragers behave given the persistent occurrence of disease threats. Studies on social insect foraging behavior typically require many hours of human labor due to the high density of individuals. To overcome this, we developed deep learning based computer vision algorithms to track foraging ants, frame-by-frame, from video footage shot under the natural conditions of a tropical forest floor at night. We found that most foragers walk in straight lines overlapping the same areas as other ants, but there is a subset of foragers with greater exploration. Consistency in walking behavior may protect most ants from infection, while foragers that explore unique portions of the trail may be more likely to encounter fungal spores implying a trade-off between resource discovery and risk avoidance.

scholarly journals Is Self-Sacrificial Competitive Altruism Primarily a Male Activity?

2012 ◽  
Vol 10 (1) ◽  
pp. 147470491201000 ◽  
Author(s):  
Francis T. McAndrew ◽  
Carin Perilloux
Keyword(s):  
Small Groups ◽  
Altruistic Behavior ◽  
Key Factors ◽  
Group Problem ◽  
Group Problem Solving ◽  
Competitive Altruism ◽  
Male Activity ◽  
Monetary Success ◽  
Experimental Partner ◽  
Cold Stressor

This study explored the basis of self-sacrificial prosocial behavior in small groups. Seventy-eight undergraduates (39M, 39F) filled out a thirty-item personality scale and then participated in a “group problem-solving study” in which the monetary success of a three-person group depended upon one of its members volunteering to endure pain (a cold stressor test) and inconvenience (being soaked in a dunk tank). There were 13 groups consisting of two females and one male, and 13 groups consisting of two males and one female. Across groups, the behavior of the altruist was judged to be more costly, challenging, and important and he/she was liked better, rewarded with more money, and preferred as a future experimental partner. Groups containing two males showed more evidence of competition to become altruists than groups containing two females, and personality traits were more effective predictors of altruistic behavior in males than in females. We conclude that competition between males and “showing off” are key factors in triggering self-sacrificial altruistic behavior.

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