---
_id: '13984'
abstract:
- lang: eng
text: "Social insects fight disease using their individual immune systems and the
cooperative\r\nsanitary behaviors of colony members. These social defenses are
well explored against\r\nexternally-infecting pathogens, but little is known about
defense strategies against\r\ninternally-infecting pathogens, such as viruses.
Viruses are ubiquitous and in the last decades\r\nit has become evident that also
many ant species harbor viruses. We present one of the first\r\nstudies addressing
transmission dynamics and collective disease defenses against viruses in\r\nants
on a mechanistic level. I successfully established an experimental ant host –
viral\r\npathogen system as a model for the defense strategies used by social
insects against internal\r\npathogen infections, as outlined in the third chapter.
In particular, we studied how garden ants\r\n(Lasius neglectus) defend themselves
and their colonies against the generalist insect virus\r\nCrPV (cricket paralysis
virus). We chose microinjections of virus directly into the ants’\r\nhemolymph
because it allowed us to use a defined exposure dose. Here we show that this is
a\r\ngood model system, as the virus is replicating and thus infecting the host.
The ants mount a\r\nclear individual immune response against the viral infection,
which is characterized by a\r\nspecific siRNA pattern, namely siRNAs mapping against
the viral genome with a peak of 21\r\nand 22 bp long fragments. The onset of this
immune response is consistent with the timeline\r\nof viral replication that starts
already within two days post injection. The disease manifests in\r\ndecreased
survival over a course of two to three weeks.\r\nRegarding group living, we find
that infected ants show a strong individual immune response,\r\nbut that their
course of disease is little affected by nestmate presence, as described in chapter\r\nfour.
Hence, we do not find social immunity in the context of viral infections in ants.\r\nNestmates,
however, can contract the virus. Using Drosophila S2R+ cells in culture, we\r\nshowed
that 94 % of the nestmates contract active virus within four days of social contact
to\r\nan infected individual. Virus is transmitted in low doses, thus not causing
disease\r\ntransmission within the colony. While virus can be transmitted during
short direct contacts,\r\nwe also assume transmission from deceased ants and show
that the nestmates’ immune\r\nsystem gets activated after contracting a low viral
dose. We find considerable potential for\r\nindirect transmission via the nest
space. Virus is shed to the nest, where it stays viable for one\r\nweek and is
also picked up by other ants. Apart from that, we want to underline the potential\r\nof
ant poison as antiviral agent. We determined that ant poison successfully inactivates
CrPV\r\nin vitro. However, we found no evidence for effective poison use to sanitize
the nest space.\r\nOn the other hand, local application of ant poison by oral
poison uptake, which is part of the\r\nants prophylactic behavioral repertoire,
probably contributes to keeping the gut of each\r\nindividual sanitized. We hypothesize
that oral poison uptake might be the reason why we did\r\nnot find viable virus
in the trophallactic fluid.\r\nThe fifth chapter encompasses preliminary data
on potential social immunization. However,\r\nour experiments do not confirm an
actual survival benefit for the nestmates upon pathogen\r\nchallenge under the
given experimental settings. Nevertheless, we do not want to rule out the\r\npossibility
for nestmate immunization, but rather emphasize that considering different\r\nexperimental
timelines and viral doses would provide a multitude of options for follow-up\r\nexperiments.\r\nIn
conclusion, we find that prophylactic individual behaviors, such as oral poison
uptake,\r\nmight play a role in preventing viral disease transmission. Compared
to colony defense\r\nagainst external pathogens, internal pathogen infections
require a stronger component of\r\nindividual physiological immunity than behavioral
social immunity, yet could still lead to\r\ncollective protection."
acknowledged_ssus:
- _id: LifeSc
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Anna
full_name: Franschitz, Anna
id: 480826C8-F248-11E8-B48F-1D18A9856A87
last_name: Franschitz
citation:
ama: Franschitz A. Individual and social immunity against viral infections in ants.
2023. doi:10.15479/at:ista:13984
apa: Franschitz, A. (2023). Individual and social immunity against viral infections
in ants. Institute of Science and Technology Austria. https://doi.org/10.15479/at:ista:13984
chicago: Franschitz, Anna. “Individual and Social Immunity against Viral Infections
in Ants.” Institute of Science and Technology Austria, 2023. https://doi.org/10.15479/at:ista:13984.
ieee: A. Franschitz, “Individual and social immunity against viral infections in
ants,” Institute of Science and Technology Austria, 2023.
ista: Franschitz A. 2023. Individual and social immunity against viral infections
in ants. Institute of Science and Technology Austria.
mla: Franschitz, Anna. Individual and Social Immunity against Viral Infections
in Ants. Institute of Science and Technology Austria, 2023, doi:10.15479/at:ista:13984.
short: A. Franschitz, Individual and Social Immunity against Viral Infections in
Ants, Institute of Science and Technology Austria, 2023.
date_created: 2023-08-08T15:33:29Z
date_published: 2023-08-08T00:00:00Z
date_updated: 2024-03-01T15:25:17Z
day: '08'
ddc:
- '570'
- '577'
degree_awarded: PhD
department:
- _id: GradSch
- _id: SyCr
doi: 10.15479/at:ista:13984
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publication_identifier:
isbn:
- 978-3-99078-034-3
issn:
- 2663 - 337X
publication_status: published
publisher: Institute of Science and Technology Austria
status: public
supervisor:
- first_name: Sylvia
full_name: Cremer, Sylvia
id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87
last_name: Cremer
orcid: 0000-0002-2193-3868
title: Individual and social immunity against viral infections in ants
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '10727'
abstract:
- lang: eng
text: "Social insects are a common model to study disease dynamics in social animals.
Even though pathogens should thrive in social insect colonies as the hosts engage
in frequent social interactions, are closely related and live in a pathogen-rich
environment, disease outbreaks are rare. This is because social insects have evolved
mechanisms to keep pathogens at bay – and fight disease as a collective. Social
insect colonies are often viewed as “superorganisms” with division of labor between
reproductive “germ-like” queens and males and “somatic” workers, which together
form an interdependent reproductive unit that parallels a multicellular body.
Superorganisms possess a “social immune system” that comprises of collective disease
defenses performed by the workers - summarized as “social immunity”. In social
groups immunization (reduced susceptibility to a parasite upon secondary exposure
to the same parasite) can e.g. be triggered by social interactions (“social immunization”).
Social immunization can be caused by (i) asymptomatic low-level infections that
are acquired during caregiving to a contagious individual that can give an immune
boost, which can induce protection upon later encounter with the same pathogen
(active immunization) or (ii) by transfer of immune effectors between individuals
(passive immunization).\r\nIn the second chapter, I built up on a study that I
co-authored that found that low-level infections can not only be protective, but
also be costly and make the host more susceptible to detrimental superinfections
after contact to a very dissimilar pathogen. I here now tested different degrees
of phylogenetically-distant fungal strains of M. brunneum and M. robertsii in
L. neglectus and can describe the occurrence of cross-protection of social immunization
if the first and second pathogen are from the same level. Interestingly, low-level
infections only provided protection when the first strain was less virulent than
the second strain and elicited higher immune gene expression.\r\nIn the third
and fourth chapters, I expanded on the role of social immunity in sexual selection,
a so far unstudied field. I used the fungus Metarhizium robertsii and the ant
Cardiocondyla obscurior as a model, as in this species mating occurs in the presence
of workers and can be studied under laboratory conditions. Before males mate with
virgin queens in the nest they engage in fierce combat over the access to their
mating partners.\r\nFirst, I focused on male-male competition in the third chapter
and found that fighting with a contagious male is costly as it can lead to contamination
of the rival, but that workers can decrease the risk of disease contraction by
performing sanitary care.\r\nIn the fourth chapter, I studied the effect of fungal
infection on survival and mating success of sexuals (freshly emerged queens and
males) and found that worker-performed sanitary care can buffer the negative effect
that a pathogenic contagion would have on sexuals by spore removal from the exposed
individuals. When social immunity was prevented and queens could contract spores
from their mating partner, very low dosages led to negative consequences: their
lifespan was reduced and they produced fewer offspring with poor immunocompetence
compared to healthy queens. Interestingly, cohabitation with a late-stage infected
male where no spore transfer was possible had a positive effect on offspring immunity
– male offspring of mothers that apparently perceived an infected partner in their
vicinity reacted more sensitively to fungal challenge than male offspring without
paternal pathogen history."
acknowledged_ssus:
- _id: LifeSc
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Sina
full_name: Metzler, Sina
id: 48204546-F248-11E8-B48F-1D18A9856A87
last_name: Metzler
orcid: 0000-0002-9547-2494
citation:
ama: Metzler S. Pathogen-mediated sexual selection and immunization in ant colonies.
2022. doi:10.15479/AT:ISTA:10727
apa: Metzler, S. (2022). Pathogen-mediated sexual selection and immunization
in ant colonies. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:10727
chicago: Metzler, Sina. “Pathogen-Mediated Sexual Selection and Immunization in
Ant Colonies.” Institute of Science and Technology Austria, 2022. https://doi.org/10.15479/AT:ISTA:10727.
ieee: S. Metzler, “Pathogen-mediated sexual selection and immunization in ant colonies,”
Institute of Science and Technology Austria, 2022.
ista: Metzler S. 2022. Pathogen-mediated sexual selection and immunization in ant
colonies. Institute of Science and Technology Austria.
mla: Metzler, Sina. Pathogen-Mediated Sexual Selection and Immunization in Ant
Colonies. Institute of Science and Technology Austria, 2022, doi:10.15479/AT:ISTA:10727.
short: S. Metzler, Pathogen-Mediated Sexual Selection and Immunization in Ant Colonies,
Institute of Science and Technology Austria, 2022.
date_created: 2022-02-04T15:45:12Z
date_published: 2022-02-07T00:00:00Z
date_updated: 2023-09-07T13:43:23Z
day: '07'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: GradSch
- _id: SyCr
doi: 10.15479/AT:ISTA:10727
ec_funded: 1
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language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
project:
- _id: 2649B4DE-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '771402'
name: Epidemics in ant societies on a chip
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
status: public
supervisor:
- first_name: Sylvia
full_name: Cremer, Sylvia
id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87
last_name: Cremer
orcid: 0000-0002-2193-3868
title: Pathogen-mediated sexual selection and immunization in ant colonies
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2022'
...
---
_id: '6435'
abstract:
- lang: eng
text: "Social insect colonies tend to have numerous members which function together
like a single organism in such harmony that the term ``super-organism'' is often
used. In this analogy the reproductive caste is analogous to the primordial germ\r\ncells
of a metazoan, while the sterile worker caste corresponds to somatic cells. The
worker castes, like tissues, are\r\nin charge of all functions of a living being,
besides reproduction. The establishment of new super-organismal units\r\n(i.e.
new colonies) is accomplished by the co-dependent castes. The term oftentimes
goes beyond a metaphor. We invoke it when we speak about the metabolic rate, thermoregulation,
nutrient regulation and gas exchange of a social insect colony. Furthermore, we
assert that the super-organism has an immune system, and benefits from ``social
immunity''.\r\n\r\nSocial immunity was first summoned by evolutionary biologists
to resolve the apparent discrepancy between the expected high frequency of disease
outbreak amongst numerous, closely related tightly-interacting hosts, living in
stable and microbially-rich environments, against the exceptionally scarce epidemic
accounts in natural populations. Social\r\nimmunity comprises a multi-layer assembly
of behaviours which have evolved to effectively keep the pathogenic enemies of
a colony at bay. The field of social immunity has drawn interest, as it becomes
increasingly urgent to stop\r\nthe collapse of pollinator species and curb the
growth of invasive pests. In the past decade, several mechanisms of\r\nsocial
immune responses have been dissected, but many more questions remain open.\r\n\r\nI
present my work in two experimental chapters. In the first, I use invasive garden
ants (*Lasius neglectus*) to study how pathogen load and its distribution among
nestmates affect the grooming response of the group. Any given group of ants will
carry out the same total grooming work, but will direct their grooming effort
towards individuals\r\ncarrying a relatively higher spore load. Contrary to expectation,
the highest risk of transmission does not stem from grooming highly contaminated
ants, but instead, we suggest that the grooming response likely minimizes spore
loss to the environment, reducing contamination from inadvertent pickup from the
substrate.\r\n\r\nThe second is a comparative developmental approach. I follow
black garden ant queens (*Lasius niger*) and their colonies from mating flight,
through hibernation for a year. Colonies which grow fast from the start, have
a lower chance of survival through hibernation, and those which survive grow at
a lower pace later. This is true for colonies of naive\r\nand challenged queens.
Early pathogen exposure of the queens changes colony dynamics in an unexpected
way: colonies from exposed queens are more likely to grow slowly and recover in
numbers only after they survive hibernation.\r\n\r\nIn addition to the two experimental
chapters, this thesis includes a co-authored published review on organisational\r\nimmunity,
where we enlist the experimental evidence and theoretical framework on which this
hypothesis is built,\r\nidentify the caveats and underline how the field is ripe
to overcome them. In a final chapter, I describe my part in\r\ntwo collaborative
efforts, one to develop an image-based tracker, and the second to develop a classifier
for ant\r\nbehaviour."
acknowledged_ssus:
- _id: Bio
- _id: ScienComp
- _id: M-Shop
- _id: LifeSc
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Barbara E
full_name: Casillas Perez, Barbara E
id: 351ED2AA-F248-11E8-B48F-1D18A9856A87
last_name: Casillas Perez
citation:
ama: Casillas Perez BE. Collective defenses of garden ants against a fungal pathogen.
2019. doi:10.15479/AT:ISTA:6435
apa: Casillas Perez, B. E. (2019). Collective defenses of garden ants against
a fungal pathogen. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:6435
chicago: Casillas Perez, Barbara E. “Collective Defenses of Garden Ants against
a Fungal Pathogen.” Institute of Science and Technology Austria, 2019. https://doi.org/10.15479/AT:ISTA:6435.
ieee: B. E. Casillas Perez, “Collective defenses of garden ants against a fungal
pathogen,” Institute of Science and Technology Austria, 2019.
ista: Casillas Perez BE. 2019. Collective defenses of garden ants against a fungal
pathogen. Institute of Science and Technology Austria.
mla: Casillas Perez, Barbara E. Collective Defenses of Garden Ants against a
Fungal Pathogen. Institute of Science and Technology Austria, 2019, doi:10.15479/AT:ISTA:6435.
short: B.E. Casillas Perez, Collective Defenses of Garden Ants against a Fungal
Pathogen, Institute of Science and Technology Austria, 2019.
date_created: 2019-05-13T08:58:35Z
date_published: 2019-05-07T00:00:00Z
date_updated: 2023-09-07T12:57:04Z
day: '07'
ddc:
- '570'
- '006'
- '578'
- '592'
degree_awarded: PhD
department:
- _id: SyCr
doi: 10.15479/AT:ISTA:6435
ec_funded: 1
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keyword:
- Social Immunity
- Sanitary care
- Social Insects
- Organisational Immunity
- Colony development
- Multi-target tracking
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
page: '183'
project:
- _id: 2649B4DE-B435-11E9-9278-68D0E5697425
call_identifier: H2020
grant_number: '771402'
name: Epidemics in ant societies on a chip
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '1999'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Sylvia M
full_name: Cremer, Sylvia M
id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87
last_name: Cremer
orcid: 0000-0002-2193-3868
title: Collective defenses of garden ants against a fungal pathogen
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2019'
...
---
_id: '819'
abstract:
- lang: eng
text: 'Contagious diseases must transmit from infectious to susceptible hosts in
order to reproduce. Whilst vectored pathogens can rely on intermediaries to find
new hosts for them, many infectious pathogens require close contact or direct
interaction between hosts for transmission. Hence, this means that conspecifics
are often the main source of infection for most animals and so, in theory, animals
should avoid conspecifics to reduce their risk of infection. Of course, in reality
animals must interact with one another, as a bare minimum, to mate. However, being
social provides many additional benefits and group living has become a taxonomically
diverse and widespread trait. How then do social animals overcome the issue of
increased disease? Over the last few decades, the social insects (ants, termites
and some bees and wasps) have become a model system for studying disease in social
animals. On paper, a social insect colony should be particularly susceptible to
disease, given that they often contain thousands of potential hosts that are closely
related and frequently interact, as well as exhibiting stable environmental conditions
that encourage microbial growth. Yet, disease outbreaks appear to be rare and
attempts to eradicate pest species using pathogens have failed time and again.
Evolutionary biologists investigating this observation have discovered that the
reduced disease susceptibility in social insects is, in part, due to collectively
performed disease defences of the workers. These defences act like a “social immune
system” for the colony, resulting in a per capita decrease in disease, termed
social immunity. Our understanding of social immunity, and its importance in relation
to the immunological defences of each insect, continues to grow, but there remain
many open questions. In this thesis I have studied disease defence in garden ants.
In the first data chapter, I use the invasive garden ant, Lasius neglectus, to
investigate how colonies mitigate lethal infections and prevent them from spreading
systemically. I find that ants have evolved ‘destructive disinfection’ – a behaviour
that uses endogenously produced acidic poison to kill diseased brood and to prevent
the pathogen from replicating. In the second experimental chapter, I continue
to study the use of poison in invasive garden ant colonies, finding that it is
sprayed prophylactically within the nest. However, this spraying has negative
effects on developing pupae when they have had their cocoons artificially removed.
Hence, I suggest that acidic nest sanitation may be maintaining larval cocoon
spinning in this species. In the next experimental chapter, I investigated how
colony founding black garden ant queens (Lasius niger) prevent disease when a
co-foundress dies. I show that ant queens prophylactically perform undertaking
behaviours, similar to those performed by the workers in mature nests. When a
co-foundress was infected, these undertaking behaviours improved the survival
of the healthy queen. In the final data chapter, I explored how immunocompetence
(measured as antifungal activity) changes as incipient black garden ant colonies
grow and mature, from the solitary queen phase to colonies with several hundred
workers. Queen and worker antifungal activity varied throughout this time period,
but despite social immunity, did not decrease as colonies matured. In addition
to the above data chapters, this thesis includes two co-authored reviews. In the
first, we examine the state of the art in the field of social immunity and how
it might develop in the future. In the second, we identify several challenges
and open questions in the study of disease defence in animals. We highlight how
social insects offer a unique model to tackle some of these problems, as disease
defence can be studied from the cell to the society. '
acknowledgement: "ERC FP7 programme (grant agreement no. 240371)\r\nI have been supremely
spoilt to work in a lab with such good resources and I must thank the wonderful
Cremer group technicians, Anna, Barbara, Eva and Florian, for all of their help
and keeping the lab up and running. You guys will probably be the most missed once
I realise just how much work you have been saving me! For the same reason, I must
say a big Dzi ę kuj ę Ci to Wonder Woman Wanda, for her tireless efforts feeding
my colonies and cranking out thousands of petri dishes and sugar tubes. Again, you
will be sorely missed now that I will have to take this task on myself. Of course,
I will be eternally indebted to Prof. Sylvia Cremer for taking me under her wing
and being a constant source of guidance and inspiration. You have given me the perfect
balance of independence and supervision. I cannot thank you enough for creating
such a great working environment and allowing me the freedom to follow my own research
questions. I have had so many exceptional opportunities – attending and presenting
at conferences all over the world, inviting me to write the ARE with you, going
to workshops in Panama and Switzerland, and even organising our own PhD course –
that I often think I must have had the best PhD in the world. You have taught me
so much and made me a scientist. I sincerely hope we get the chance to work together
again in the future. Thank you for everything. I must also thank my PhD Committee,
Daria Siekhaus and Jacobus “Koos” Boomsma, for being very supportive throughout
the duration of my PhD. "
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Christopher
full_name: Pull, Christopher
id: 3C7F4840-F248-11E8-B48F-1D18A9856A87
last_name: Pull
orcid: 0000-0003-1122-3982
citation:
ama: Pull C. Disease defence in garden ants. 2017. doi:10.15479/AT:ISTA:th_861
apa: Pull, C. (2017). Disease defence in garden ants. Institute of Science
and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_861
chicago: Pull, Christopher. “Disease Defence in Garden Ants.” Institute of Science
and Technology Austria, 2017. https://doi.org/10.15479/AT:ISTA:th_861.
ieee: C. Pull, “Disease defence in garden ants,” Institute of Science and Technology
Austria, 2017.
ista: Pull C. 2017. Disease defence in garden ants. Institute of Science and Technology
Austria.
mla: Pull, Christopher. Disease Defence in Garden Ants. Institute of Science
and Technology Austria, 2017, doi:10.15479/AT:ISTA:th_861.
short: C. Pull, Disease Defence in Garden Ants, Institute of Science and Technology
Austria, 2017.
date_created: 2018-12-11T11:48:40Z
date_published: 2017-09-26T00:00:00Z
date_updated: 2023-09-28T11:31:32Z
day: '26'
ddc:
- '576'
- '577'
- '578'
- '579'
- '590'
- '592'
degree_awarded: PhD
department:
- _id: SyCr
doi: 10.15479/AT:ISTA:th_861
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language:
- iso: eng
month: '09'
oa: 1
oa_version: Published Version
page: '122'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '6830'
pubrep_id: '861'
related_material:
record:
- id: '616'
relation: part_of_dissertation
status: public
- id: '806'
relation: part_of_dissertation
status: public
- id: '734'
relation: part_of_dissertation
status: public
- id: '732'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Sylvia M
full_name: Cremer, Sylvia M
id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87
last_name: Cremer
orcid: 0000-0002-2193-3868
title: Disease defence in garden ants
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2017'
...
---
_id: '1395'
abstract:
- lang: eng
text: In this thesis I studied various individual and social immune defences employed
by the invasive garden ant Lasius neglectus mostly against entomopathogenic fungi. The
first two chapters of this thesis address the phenomenon of 'social immunisation'.
Social immunisation, that is the immunological protection of group members due
to social contact to a pathogen-exposed nestmate, has been described in various
social insect species against different types of pathogens. However, in the case
of entomopathogenic fungi it has, so far, only been demonstrated that social immunisation
exists at all. Its underlying mechanisms r any other properties were, however,
unknown. In the first chapter of this thesis I identified the mechanistic basis
of social immunisation in L. neglectus against the entomopathogenous fungus Metarhizium.
I could show that nestmates of a pathogen-exposed individual contract low-level
infections due to social interactions. These low-level infections are, however,
non-lethal and cause an active stimulation of the immune system, which protects
the nestmates upon subsequent pathogen encounters. In the second chapter of this
thesis I investigated the specificity and colony level effects of social immunisation.
I demonstrated that the protection conferred by social immunisation is highly
specific, protecting ants only against the same pathogen strain. In addition,
depending on the respective context, social immunisation may even cause fitness
costs. I further showed that social immunisation crucially affects sanitary behaviour
and disease dynamics within ant groups. In the third chapter of this thesis I
studied the effects of the ectosymbiotic fungus Laboulbenia formicarum on its
host L. neglectus. Although Laboulbeniales are the largest order of insect-parasitic
fungi, research concerning host fitness consequence is sparse. I showed that highly
Laboulbenia-infected ants sustain fitness costs under resource limitation, however,
gain fitness benefits when exposed to an entomopathogenus fungus. These effects
are probably cause by a prophylactic upregulation of behavioural as well as physiological
immune defences in highly infected ants.
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Matthias
full_name: Konrad, Matthias
id: 46528076-F248-11E8-B48F-1D18A9856A87
last_name: Konrad
citation:
ama: 'Konrad M. Immune defences in ants: Effects of social immunisation and a fungal
ectosymbiont in the ant Lasius neglectus. 2014.'
apa: 'Konrad, M. (2014). Immune defences in ants: Effects of social immunisation
and a fungal ectosymbiont in the ant Lasius neglectus. Institute of Science
and Technology Austria.'
chicago: 'Konrad, Matthias. “Immune Defences in Ants: Effects of Social Immunisation
and a Fungal Ectosymbiont in the Ant Lasius Neglectus.” Institute of Science and
Technology Austria, 2014.'
ieee: 'M. Konrad, “Immune defences in ants: Effects of social immunisation and a
fungal ectosymbiont in the ant Lasius neglectus,” Institute of Science and Technology
Austria, 2014.'
ista: 'Konrad M. 2014. Immune defences in ants: Effects of social immunisation and
a fungal ectosymbiont in the ant Lasius neglectus. Institute of Science and Technology
Austria.'
mla: 'Konrad, Matthias. Immune Defences in Ants: Effects of Social Immunisation
and a Fungal Ectosymbiont in the Ant Lasius Neglectus. Institute of Science
and Technology Austria, 2014.'
short: 'M. Konrad, Immune Defences in Ants: Effects of Social Immunisation and a
Fungal Ectosymbiont in the Ant Lasius Neglectus, Institute of Science and Technology
Austria, 2014.'
date_created: 2018-12-11T11:51:46Z
date_published: 2014-02-01T00:00:00Z
date_updated: 2023-09-07T11:38:56Z
day: '01'
degree_awarded: PhD
department:
- _id: SyCr
language:
- iso: eng
month: '02'
oa_version: None
page: '131'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '5814'
status: public
supervisor:
- first_name: Sylvia M
full_name: Cremer, Sylvia M
id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87
last_name: Cremer
orcid: 0000-0002-2193-3868
title: 'Immune defences in ants: Effects of social immunisation and a fungal ectosymbiont
in the ant Lasius neglectus'
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2014'
...
---
_id: '1404'
abstract:
- lang: eng
text: "The co-evolution of hosts and pathogens is characterized by continuous adaptations
of both parties. Pathogens of social insects need to adapt towards disease defences
at two levels: 1) individual immunity of each colony member consisting of behavioural
defence strategies as well as humoral and cellular immune responses and 2) social
immunity that is collectively performed by all group members comprising behavioural,
physiological and organisational defence strategies.\r\n\r\nTo disentangle the
selection pressure on pathogens by the collective versus individual level of disease
defence in social insects, we performed an evolution experiment using the Argentine
Ant, Linepithema humile, as a host and a mixture of the general insect pathogenic
fungus Metarhizium spp. (6 strains) as a pathogen. We allowed pathogen evolution
over 10 serial host passages to two different evolution host treatments: (1) only
individual host immunity in a single host treatment, and (2) simultaneously acting
individual and social immunity in a social host treatment, in which an exposed
ant was accompanied by two untreated nestmates.\r\n\r\nBefore starting the pathogen
evolution experiment, the 6 Metarhizium spp. strains were characterised concerning
conidiospore size killing rates in singly and socially reared ants, their competitiveness
under coinfecting conditions and their influence on ant behaviour. We analysed
how the ancestral atrain mixture changed in conidiospere size, killing rate and
strain composition dependent on host treatment (single or social hosts) during
10 passages and found that killing rate and conidiospere size of the pathogen
increased under both evolution regimes, but different depending on host treatment.\r\n\r\nTesting
the evolved strain mixtures that evolved under either the single or social host
treatment under both single and social current rearing conditions in a full factorial
design experiment revealed that the additional collective defences in insect societies
add new selection pressure for their coevolving pathogens that compromise their
ability to adapt to its host at the group level. To our knowledge, this is the
first study directly measuring the influence of social immunity on pathogen evolution."
acknowledgement: This work was funded by the DFG and the ERC.
alternative_title:
- IST Austria Thesis
author:
- first_name: Miriam
full_name: Stock, Miriam
id: 42462816-F248-11E8-B48F-1D18A9856A87
last_name: Stock
citation:
ama: Stock M. Evolution of a fungal pathogen towards individual versus social immunity
in ants. 2014.
apa: Stock, M. (2014). Evolution of a fungal pathogen towards individual versus
social immunity in ants. IST Austria.
chicago: Stock, Miriam. “Evolution of a Fungal Pathogen towards Individual versus
Social Immunity in Ants.” IST Austria, 2014.
ieee: M. Stock, “Evolution of a fungal pathogen towards individual versus social
immunity in ants,” IST Austria, 2014.
ista: Stock M. 2014. Evolution of a fungal pathogen towards individual versus social
immunity in ants. IST Austria.
mla: Stock, Miriam. Evolution of a Fungal Pathogen towards Individual versus
Social Immunity in Ants. IST Austria, 2014.
short: M. Stock, Evolution of a Fungal Pathogen towards Individual versus Social
Immunity in Ants, IST Austria, 2014.
date_created: 2018-12-11T11:51:49Z
date_published: 2014-04-01T00:00:00Z
date_updated: 2021-01-12T06:50:30Z
day: '01'
department:
- _id: SyCr
language:
- iso: eng
month: '04'
oa_version: None
page: '101'
publication_status: published
publisher: IST Austria
publist_id: '5803'
status: public
supervisor:
- first_name: Sylvia M
full_name: Cremer, Sylvia M
id: 2F64EC8C-F248-11E8-B48F-1D18A9856A87
last_name: Cremer
orcid: 0000-0002-2193-3868
title: Evolution of a fungal pathogen towards individual versus social immunity in
ants
type: dissertation
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2014'
...