Post by Deleted on Nov 29, 2011 9:16:39 GMT 1
On Antdude's forum, this is a part of a Lasius umbratus guide/journal that I've been working on for some time. The original thread was supposed to be a culmination of knowledge on this subject that I thought barely existed. Over the course of the summer, I've brought together a decent amount of information, from sources recent and quite old, both. Here is a modest summary of social parasitism in ants. If you have anything to add or ask, please do so! I'm on the lookout for more species references for the various modes of parasitism, as well as any other videos or books that represent crucial parts in the life of a parasite colony (e.g. colony founding, slave raids.) I'm looking to improve this! I want this little article to be as helpful as possible, and I will be keeping it up to date as I learn more.
I've converted this from HTML to BBCode with a program, so it took quite a bit of patching up before it was back to its original state. If you notice any broken links or errors, please let me know.
A social parasite is any species which, rather than founding a colony with its own resources, infiltrates the existing colony of a host species and uses the workers or resources in the colony to raise the parasite's own workers or reproductives. The three basic types of social parasitism are temporary, slave raider, and permanent inquiline.
Temporary social parasitism is when one species of ant must start their colony with the aid of another species' nest, but are later able to take care of themselves when the host colony dies out. This is usually undertaken by a parasitic queen replacing the living or deceased queen of a host colony. Some ants are only interested in the host colony's brood, and certain queens will kill or scare off all of the host nest's adult members, raising any brood left behind as her own (i.e. Formica sanguinea); others take advantage of the host colony's entire workforce, convincing the resident workers that she deserves to be the colony's only reproductive. In the case of the latter, all of the reproductive ants that happen to be in the colony (including the mother queen) are often killed and eaten. The workers of the parasitic queen gradually replace the members of the host colony, until only the parasitic species remains, taking over all responsibilities for the nest. Formica exsecta, Formica microgyna, Formuca rufa, Lasius umbratus, Lasius claviger, Lasius fuliginosus, Aphaenogaster tennesseensis, and Dorymyrmex reginicula are some of the many that can be cited for this behavior.
Obligate slave raiders are famous for their ability and enthusiasm to force their way into the nests of other ants and steal their brood. Many raiders are adapted with enlarged Durfour's glands, which emit relatively large quantities of panic-inducing alarm pheromones on command. The resulting hysteria causes the targeted defenders to fall apart and flee, leaving much of their brood to be harvested by raiders. Stolen brood from these raids are sometimes used as food for the colony, but any surviving pupae will eclose within the nest. These new workers imprint on the colony they are born in, and work for the raider's nest as if it were their own. Many suggest that this behavior be called something other than slavery, since the slave workers live no differently than they would in their original nest. Facultative slave raiders do not actually need slaves to survive and may be considered temporary parasites, however a majority of raiders are obligate; they are so specialized for combat that it has encroached on their physical or behavioral ability to perform more domestic tasks, and they now depend very much on their slaves. Good examples of obligate slave raiders include: Polyergus, Formica subintegra, and Protomognathus. Slave raider colonies take over their host by forceful means or with chemical trickery; often both.
The nanitics of a slave raiding species are often small, much as if the queen had raised them on her own. Since slave raiders are almost unanimously larger than the species which they raid, the reason for these small raiders to even exist has been brought to question. It's likely that their simple presence helps to adjust the host workers to give appropriate care for the parasites yet to come.
Permanent inquiline social parasites are ants that depend on a host species' nest and its workers for the duration of the colony's existence. Two form of inquilinism are ants who don't have workers and those who must inhabit the nests of other ants.
Workerless social parasites do occur in the ant world, and are rather complicated and various, so I can only give approximations of how they live. Workerless parasites often search for the nests of orphaned colonies and latch onto a worker to be carried inside (they tend to be very small). Once they have infiltrated, they take control of the colony with relative ease. Most queens must make a prodigious output, quickly, because they can only produce reproductive males and females, and only have as long as the lifespan of the youngest worker in the colony to do so. When the last host worker dies, the parasitic ants remaining in the nest starve and vanish. Males of these parasites are sometimes wingless, the species reproducing through inbreeding; these colonies are carefully managed to be queen-biased, with only as many males as it takes to fertilize each female. Queens tend to (but don't always) look relatively similar to the male body-type of most other ants. They fly out in search of their own host colony to continue the cycle. Workerless parasites are often very rare within their range. I think that the most notable are: Anergates, Pogonomyrmex colei, Temnothorax minutissimus, Pseudomyrmex leptosus and Teleutomyrmex. Not all workerless inquilines require perishing colonies; Teleutomyrmex queens are adapted to cling onto living queens with their largely hooked feet, being fed while keeping the host colony alive considerably longer (Temnothorax minutissimus also showing this behavior). Many inquiline Myrmica manipulate the host queen and workers so that the host's eggs never produce reproductives, leaving the parasite to create the colony's alates.
Guest ants come from a niche of parasitism where two complete colonies exist, in the long-term, within the same nest. These parasites usually prey upon the brood of their hosts, which are often so prolific that the host colony doesn't largely suffer from the losses. Megalomyrmex symmetochus, Formicoxenus, and Strongylognathus are good examples. It's been noted that rather than directly using their host species' chemical language to hold status in the colony, these ants tend to strive for "chemical insignificance," effectively making themselves unnoticeable to their host species.
Colony founding of social parasites
Adoption of social parasites is often dependent on their ability to persuade and/or communicate with a host species. Most targets are close enough relatives of the parasite species that communication isn't particularly difficult to achieve. However, the most daunting task of a parasitic queen is convincing her host workers that she should be the sole, dominant reproductive force in the colony. Most workers are immediately hostile at the presence of a foreign ant and queen, but if the message of dominance is received, it must also be weighed upon. It takes a majority of the workers in the colony to decide which queen should be supported.
The first contact a parasitic queen makes with her host species is from a rather broad repertoire, and these first moves can vary between species of parasite and parasites of the same species. Granted some types of ant will use some strategies more often than others, there doesn't seem to be many rigid patterns of infiltration.
A social parasite may:
Once the queen has gained entry, she often heads for the colony's queen or brood. Social parasites have been observed to seek out and sit atop piles of pupae, which must offer some support in the form of callow ants who are passive and may imprint on her (in addition to the possibility that certain scents in the pile might help her to settle into the colony). The queen will usually be a target of the social parasite at one point or another. A number of parasitic queens have evolved to be quite combative, with broadened heads and sharper mandibles; some primarily or additionally make strong use of chemical language to convince the host workers to remove their own queen. The parasite may peacefully sit alongside of the host queen for as long as days or weeks before one of them is removed.
Worker ants are very particular about the queen they serve. Any queen may be evicted or killed if she is found to be unsuitable as the colony's primary reproductive, which is often the fate of social parasites who are difficult to recognize by their host species. An unlucky parasitic queen may spend more than a week in a host colony only to be noticed and rejected by them.
Some queens (namely Lasius parasites) simply perish in captivity within the first few days alone, in a host colony, or even in the company of the colony they were born in. Many of the casualties in laboratory experiments come from queens who have died this way before they could even face the trials of adoption. This, however, shouldn't discourage an enthusiastic keeper from trying their hands at these ants; some queens will succumb to this mysterious death, but once a queen is truly settled into a captive colony, she will no longer be vulnerable to whatever causes this.
Worker aggression is probably the second most frequent cause of death for captive social parasites. Even if the resident queen is somewhat lacking in their eyes, they can be reluctant to eject a functional queen in favor of a questionable one (this includes workers who have been removed from the colony recently, and do not consider themselves to be without a queen). Some parasitic queens function well in cold temperatures, and may use this to their advantage when infiltrating the sluggish colony of their host. If the colony has been without a queen for some time, then the workers are much more receptive to a replacement.
Her are some things to keep in mind if you are thinking about performing an introduction (this specifically regards temporary parasites, but some of this is relevant to the other forms):
It can days, weeks, or months before your queen begins to lay her first eggs. There could be something going on behind the scenes during this time; for whatever reason, a parasitic queen with a usurped colony will not always begin laying straight away. Once she has her first egg, however, the most difficult phase of her life is basically over; it is a sign not only that she is fully accepted by her host workers but that she is adapted to captivity, in good health, and is finally ready to begin her colony. While there are still a few hurdles to overcome, you can now relax or celebrate. Since your queen already has a selection of host workers to keep her fed, she will begin to produce eggs to match the hypothetical age of the colony (a 50 host worker colony will cause her to lay eggs as if she is already about one year old, etc.)
One thing that can be said for temporary social parasitism is that while a queen will get a huge amount of free labor, it isn't exactly of the best quality; it's a rather tumultuous time in the colony's life. During the early stages, host workers are rather aggressive, careless, or confused when they interact with members of the parasite species (and vice versa.) Brood of one species can be eaten or neglected by the other. Workers will be bullied and occasionally killed to be fed to the larvae. These behaviors are likely the result of a language barrier, but it may also be perceived as an immunity response of the host species to the ants who parasitise them. Unless this behavior stalls the colony until the host workers age and die and there are not parasite workers to take over (which is quite unlikely to happen,) the colony will not suffer from the transition for very long. Once the first parasite worker successfully matures, the situation usually changes for the better.
Media:
Videos:
Semi-Claustral and Social Parasitic Queens - Tutorial #22 (AntsCanada) A description of social parasites, with brief notes on failed attempts for Lasius claviger.
Phase 1: Successful - Introducing Parasite Queen (Lasius claviger) to Host Workers (Lasius neoniger) (AntsCanada) A method for the introduction of social parasites to host workers that reduces the aggression of both groups long enough for them to accept one another.
Queen Lasius umbratus in the nest of Lasius niger (Lewandowka) Footage of a Lasius umbratus queen peacefully interacting with a queen and colony of Lasius niger.
Ant Chat Episode 35 My Formica pergandei Colony (MrILoveTheAnts) Nice documentation of a Formica pergandei colony, a social parasite and facultative slave raider.
Polyergus Queen Steals Different Ant's Kingdom (National Geographic) A colony founding of Polyergus.
Polyergus Enslaves Other Ants (National Geographic) A good portrayal of slave raiding in ants by Polyergus.
PDFs:
Experiments on the Adoption of Lasius, Formica and Polyergus Queens by Colonies of Alien Species (Maurice Cole Tanquary) Contains very useful introduction and adoption data for several social parasites, including Aphaenogaster tennesseensis.
British Ants: Their Life-History and Classification (Horace St. John Kelly Donisthorpe, 1915) Offers information about the biology of ants, including Anergates, Formica sanguinea, Lasius umbratus, and Lasius fuliginosus.
I've converted this from HTML to BBCode with a program, so it took quite a bit of patching up before it was back to its original state. If you notice any broken links or errors, please let me know.
A social parasite is any species which, rather than founding a colony with its own resources, infiltrates the existing colony of a host species and uses the workers or resources in the colony to raise the parasite's own workers or reproductives. The three basic types of social parasitism are temporary, slave raider, and permanent inquiline.
Temporary social parasitism is when one species of ant must start their colony with the aid of another species' nest, but are later able to take care of themselves when the host colony dies out. This is usually undertaken by a parasitic queen replacing the living or deceased queen of a host colony. Some ants are only interested in the host colony's brood, and certain queens will kill or scare off all of the host nest's adult members, raising any brood left behind as her own (i.e. Formica sanguinea); others take advantage of the host colony's entire workforce, convincing the resident workers that she deserves to be the colony's only reproductive. In the case of the latter, all of the reproductive ants that happen to be in the colony (including the mother queen) are often killed and eaten. The workers of the parasitic queen gradually replace the members of the host colony, until only the parasitic species remains, taking over all responsibilities for the nest. Formica exsecta, Formica microgyna, Formuca rufa, Lasius umbratus, Lasius claviger, Lasius fuliginosus, Aphaenogaster tennesseensis, and Dorymyrmex reginicula are some of the many that can be cited for this behavior.
Obligate slave raiders are famous for their ability and enthusiasm to force their way into the nests of other ants and steal their brood. Many raiders are adapted with enlarged Durfour's glands, which emit relatively large quantities of panic-inducing alarm pheromones on command. The resulting hysteria causes the targeted defenders to fall apart and flee, leaving much of their brood to be harvested by raiders. Stolen brood from these raids are sometimes used as food for the colony, but any surviving pupae will eclose within the nest. These new workers imprint on the colony they are born in, and work for the raider's nest as if it were their own. Many suggest that this behavior be called something other than slavery, since the slave workers live no differently than they would in their original nest. Facultative slave raiders do not actually need slaves to survive and may be considered temporary parasites, however a majority of raiders are obligate; they are so specialized for combat that it has encroached on their physical or behavioral ability to perform more domestic tasks, and they now depend very much on their slaves. Good examples of obligate slave raiders include: Polyergus, Formica subintegra, and Protomognathus. Slave raider colonies take over their host by forceful means or with chemical trickery; often both.
The nanitics of a slave raiding species are often small, much as if the queen had raised them on her own. Since slave raiders are almost unanimously larger than the species which they raid, the reason for these small raiders to even exist has been brought to question. It's likely that their simple presence helps to adjust the host workers to give appropriate care for the parasites yet to come.
Permanent inquiline social parasites are ants that depend on a host species' nest and its workers for the duration of the colony's existence. Two form of inquilinism are ants who don't have workers and those who must inhabit the nests of other ants.
Workerless social parasites do occur in the ant world, and are rather complicated and various, so I can only give approximations of how they live. Workerless parasites often search for the nests of orphaned colonies and latch onto a worker to be carried inside (they tend to be very small). Once they have infiltrated, they take control of the colony with relative ease. Most queens must make a prodigious output, quickly, because they can only produce reproductive males and females, and only have as long as the lifespan of the youngest worker in the colony to do so. When the last host worker dies, the parasitic ants remaining in the nest starve and vanish. Males of these parasites are sometimes wingless, the species reproducing through inbreeding; these colonies are carefully managed to be queen-biased, with only as many males as it takes to fertilize each female. Queens tend to (but don't always) look relatively similar to the male body-type of most other ants. They fly out in search of their own host colony to continue the cycle. Workerless parasites are often very rare within their range. I think that the most notable are: Anergates, Pogonomyrmex colei, Temnothorax minutissimus, Pseudomyrmex leptosus and Teleutomyrmex. Not all workerless inquilines require perishing colonies; Teleutomyrmex queens are adapted to cling onto living queens with their largely hooked feet, being fed while keeping the host colony alive considerably longer (Temnothorax minutissimus also showing this behavior). Many inquiline Myrmica manipulate the host queen and workers so that the host's eggs never produce reproductives, leaving the parasite to create the colony's alates.
Guest ants come from a niche of parasitism where two complete colonies exist, in the long-term, within the same nest. These parasites usually prey upon the brood of their hosts, which are often so prolific that the host colony doesn't largely suffer from the losses. Megalomyrmex symmetochus, Formicoxenus, and Strongylognathus are good examples. It's been noted that rather than directly using their host species' chemical language to hold status in the colony, these ants tend to strive for "chemical insignificance," effectively making themselves unnoticeable to their host species.
Colony founding of social parasites
Adoption of social parasites is often dependent on their ability to persuade and/or communicate with a host species. Most targets are close enough relatives of the parasite species that communication isn't particularly difficult to achieve. However, the most daunting task of a parasitic queen is convincing her host workers that she should be the sole, dominant reproductive force in the colony. Most workers are immediately hostile at the presence of a foreign ant and queen, but if the message of dominance is received, it must also be weighed upon. It takes a majority of the workers in the colony to decide which queen should be supported.
The first contact a parasitic queen makes with her host species is from a rather broad repertoire, and these first moves can vary between species of parasite and parasites of the same species. Granted some types of ant will use some strategies more often than others, there doesn't seem to be many rigid patterns of infiltration.
A social parasite may:
- sit at the entrance of a nest and grab one of the first workers to emerge. Sometimes the worker is killed, else the queen may simply carry (or be carried by) her captive for a short while before releasing her. Queens have been seen to vigorously lick the worker's body, pausing to groom herself (presumably to acquire the worker's scent). A parasite may also carry her hostage into the nest with her, to which the nest's defenders will be less aggressive towards the intruder.
- become very still; whether this is some pose of submission or feigning death, the queen may be carried inside of the nest by one of the workers.
- excavate her own chamber within the nest. It's assumed that the chamber gives her some protection while she may adjust to the colony at her leisure. The parasitic queen may also be able to send propaganda to the workers from this location.
- simply barge in. Some parasites are well equipped to defuse any hostile workers she might meet on her way into the nest. (Though to gain permanent residency she must still make herself the colony's queen.) Some queens don't even intend to subvert the queen, and are only interested in stealing the colony's brood.
Once the queen has gained entry, she often heads for the colony's queen or brood. Social parasites have been observed to seek out and sit atop piles of pupae, which must offer some support in the form of callow ants who are passive and may imprint on her (in addition to the possibility that certain scents in the pile might help her to settle into the colony). The queen will usually be a target of the social parasite at one point or another. A number of parasitic queens have evolved to be quite combative, with broadened heads and sharper mandibles; some primarily or additionally make strong use of chemical language to convince the host workers to remove their own queen. The parasite may peacefully sit alongside of the host queen for as long as days or weeks before one of them is removed.
Worker ants are very particular about the queen they serve. Any queen may be evicted or killed if she is found to be unsuitable as the colony's primary reproductive, which is often the fate of social parasites who are difficult to recognize by their host species. An unlucky parasitic queen may spend more than a week in a host colony only to be noticed and rejected by them.
Some queens (namely Lasius parasites) simply perish in captivity within the first few days alone, in a host colony, or even in the company of the colony they were born in. Many of the casualties in laboratory experiments come from queens who have died this way before they could even face the trials of adoption. This, however, shouldn't discourage an enthusiastic keeper from trying their hands at these ants; some queens will succumb to this mysterious death, but once a queen is truly settled into a captive colony, she will no longer be vulnerable to whatever causes this.
Worker aggression is probably the second most frequent cause of death for captive social parasites. Even if the resident queen is somewhat lacking in their eyes, they can be reluctant to eject a functional queen in favor of a questionable one (this includes workers who have been removed from the colony recently, and do not consider themselves to be without a queen). Some parasitic queens function well in cold temperatures, and may use this to their advantage when infiltrating the sluggish colony of their host. If the colony has been without a queen for some time, then the workers are much more receptive to a replacement.
Her are some things to keep in mind if you are thinking about performing an introduction (this specifically regards temporary parasites, but some of this is relevant to the other forms):
- In the wild, it is possible that the host colony of a social parasite already has a queen which may need to be removed. When attempting an adoption in captivity, there is rarely any reason to include a host queen in this introduction. Workers are all your temporary parasite needs, and the presence of their queen only hurts the odds favoring your parasite.
- Some ants, particularly Formica parasites (facultative or obligate), are significantly more violent when they start a colony; a queen will force her way into a nest and kill or scare away the adult members of the colony, raising any abandoned brood as her own. These queens are adapted with the typical combatant's body type, but weaponize their chemical vocabulary rather than utilizing it for diplomacy. Invading Formica parasites release a scent associated with alarm when they infiltrate a nest; the defenders have a heavy compulsion to grab as much brood as they can carry and flee the nest entirely rather than fight. Any workers that stay are under threat of the rather aggressive parasite queen, who fiercely defends her claim of the nest. Adoption does occur with the queens who use this strategy, but it is more often a matter of the queen adopting the workers than the workers adopting the queen. Be sure your social parasite isn't one of these types before exposing her to any workers, since these introductions most often lead to death and are an unnecessary risk; simply give your queen pupae of her host.
- Ants imprint! If you present your social parasite with a callow worker, the worker will accept the queen as a nestmate. Whether or not the queen will be hostile to the worker is hard to predict, but if each accepts the other, then building up a host colony for your queen is simply a matter of brood boosting. On the subject of pupae: many social parasite queens lack the parental instincts to care for brood, but pupae should be considered a possible alternative to workers. Some social parasites merely steal the brood of their host to start a colony, and these will effectively be cared for by the queen until they eclose. Naked pupae may successfully eclose unaided; these should always be used in the case of non-Formicinae social parasites instead of adult host workers, since there is so much less of a risk. Hypothetically a Formicinae pupae, carefully stripped of its protective cocoon, has the potential to eclose on its own (but you definitely need the right tools and techniques, else you will certainly crush the poor pupa.) Remember that once the colony has a few capable workers, you can easily brood-boost the population to whatever you desire.
//May 9, 2012//
The surest way to obtain a callow is to capture a small number of workers and pupae. Simply wait for one of the pupae to eclose, then (being very careful) use a brush or toothpick to remove it from the other ants and present it to the parasitic queen. This method can take anywhere between a day and weeks to undergo, so make sure that the queen is comfortable during this time. - Start small. It only takes one worker to be aggressive towards a queen, and only one worker to be friendly to a queen. Try to keep the magnitude of your introduction small to begin with. Ants operate somewhat empathically; if two workers find a queen agreeable, then a single additional worker will likely also find that queen agreeable because it is so popular. You may add as many workers from that host colony as you desire when your queen is accepted by a few. Be warned that as many times as you add workers, there is a chance that some of them will have trouble with the queen. Often these rogue workers are corrected or killed by the rest of the colony, but it is a risk to the parasite queen that should be mentioned. Social parasites do love to be pampered from the start, and so a healthy host colony of at least 50 workers is ideal for a parasite queen. The more workers she has around her, the heavier her output of eggs will be.
- If possible, make sure that the group of workers you use for an introduction to a parasitic queen have been away from their colony long enough so that they consider themselves orphaned. Social parasites are most successful when they infiltrate colonies that have no queen.
- Cold temperatures will slow down all the ants involved in an introduction, lowering their capacity to do damage to one another. This doesn't guarantee that the ants can't kill each other, but it can sometimes make combat too inconvenient. The best time to do this is during the natural period of hibernation.
Once she is adopted
It can days, weeks, or months before your queen begins to lay her first eggs. There could be something going on behind the scenes during this time; for whatever reason, a parasitic queen with a usurped colony will not always begin laying straight away. Once she has her first egg, however, the most difficult phase of her life is basically over; it is a sign not only that she is fully accepted by her host workers but that she is adapted to captivity, in good health, and is finally ready to begin her colony. While there are still a few hurdles to overcome, you can now relax or celebrate. Since your queen already has a selection of host workers to keep her fed, she will begin to produce eggs to match the hypothetical age of the colony (a 50 host worker colony will cause her to lay eggs as if she is already about one year old, etc.)
One thing that can be said for temporary social parasitism is that while a queen will get a huge amount of free labor, it isn't exactly of the best quality; it's a rather tumultuous time in the colony's life. During the early stages, host workers are rather aggressive, careless, or confused when they interact with members of the parasite species (and vice versa.) Brood of one species can be eaten or neglected by the other. Workers will be bullied and occasionally killed to be fed to the larvae. These behaviors are likely the result of a language barrier, but it may also be perceived as an immunity response of the host species to the ants who parasitise them. Unless this behavior stalls the colony until the host workers age and die and there are not parasite workers to take over (which is quite unlikely to happen,) the colony will not suffer from the transition for very long. Once the first parasite worker successfully matures, the situation usually changes for the better.
Media:
Videos:
Semi-Claustral and Social Parasitic Queens - Tutorial #22 (AntsCanada) A description of social parasites, with brief notes on failed attempts for Lasius claviger.
Phase 1: Successful - Introducing Parasite Queen (Lasius claviger) to Host Workers (Lasius neoniger) (AntsCanada) A method for the introduction of social parasites to host workers that reduces the aggression of both groups long enough for them to accept one another.
Queen Lasius umbratus in the nest of Lasius niger (Lewandowka) Footage of a Lasius umbratus queen peacefully interacting with a queen and colony of Lasius niger.
Ant Chat Episode 35 My Formica pergandei Colony (MrILoveTheAnts) Nice documentation of a Formica pergandei colony, a social parasite and facultative slave raider.
Polyergus Queen Steals Different Ant's Kingdom (National Geographic) A colony founding of Polyergus.
Polyergus Enslaves Other Ants (National Geographic) A good portrayal of slave raiding in ants by Polyergus.
PDFs:
Experiments on the Adoption of Lasius, Formica and Polyergus Queens by Colonies of Alien Species (Maurice Cole Tanquary) Contains very useful introduction and adoption data for several social parasites, including Aphaenogaster tennesseensis.
British Ants: Their Life-History and Classification (Horace St. John Kelly Donisthorpe, 1915) Offers information about the biology of ants, including Anergates, Formica sanguinea, Lasius umbratus, and Lasius fuliginosus.