The extreme, workerless inquilines.

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The extreme, workerless inquilines.

Beitragvon Teleutotje » Samstag 28. Januar 2017, 09:34

You all probably know by now that my biggest interests in ants are centered on Teleutomyrmex and Anergates (and a few, or many, other groups and behaviors....). So, in the cours of time I compiled some files and reviews about these "beasties" and I had some very good discussions about them online. But now I think it is time for most, but not all, of them to be summarised here... I hope you will enjoy the next few replies...
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The extreme, workerless inquilines.

Beitragvon Teleutotje » Samstag 28. Januar 2017, 09:40

The extreme, workerless inquilines.

The species.

Teleutomyrmex Kutter, 1950

01) Teleutomyrmex schneideri Kutter, 1950
02) Teleutomyrmex kutteri Tinaut, 1990

Anergates Forel, 1874.

03) Anergates atratulus (Schenck, 1852) (= Myrmica atratula Schenck, 1852)
04) Anergates friedlandi Creighton, 1934

Tetramorium Mayr, 1855
(Only a few species in a big genus.)

05) Tetramorium microgyna Santschi, 1918
06) Tetramorium parasiticum Bolton, 1980

Pheidole Westwood, 1839
(Only a few species in a big genus.)

07) Pheidole neokohli Wilson, 1984 (= Anergatides kohli Wasman, 1915)
(not Pheidole kohli Mayr, 1901)
08) Pheidole acutidens (Santschi, 1922) (= Bruchomyrma acutidens Santschi, 1922)
09) Pheidole argentina (Bruch, 1932) (= Gallardomyrma argentina Bruch, 1932)
10) Pheidole parasitica Wilson, 1984

Nylanderia Emery, 1906
(before 2010: Paratrechina Motschoulsky, 1863)
(Only a few species in a big genus.)

11) At least two undescribed species!

Excluded from the extreme, workerless inquilines.
Once this species was included in the extreme, workerless inquilines but now it is considered to be a workerless inquiline without extreme reductions, e.g. no pupoid males but normal ones. The decision to exclude it was made by Edward Osborne Wilson in 1984 in a study of the inquilines in the genus Pheidole.

Pheidole Westwood, 1839
(Only one species in a big genus.)

12) Pheidole kusnezovi Wilson, 2003 (= Pheidole symbiotica (Kusnezov, 1952))
(= Eriopheidole symbiotica Kusnezov, 1952)
(not Pheidole symbiotica Wasmann, 1909)

Distribution.

01, 02, 03: Europe.
04, 11: North America.
05, 06: Southern Africa.
07: Central Africa.
08, 09, 12: South America.
10: India.

Host species.

01, 02, 03, 04, 05, 06: Certain species of the genus Tetramorium Mayr, 1855.
01) T. caespitum (Linnaeus, 1758) and/or T. impurum (Förster, 1850)
02) T. caespitum (Linnaeus, 1758)
03) T. caespitum (Linnaeus, 1758)
04) T. caespitum (Linnaeus, 1758)
05) T. sericeiventre Emery, 1877 and T. sepositum Santschi, 1918
06) T. avium Bolton, 1980

07, 08, 09, 10, 12: Certain species of the genus Pheidole Westwood, 1839.
07) P. megacephala (Fabricius, 1793) subsp. melancholica Santschi, 1912
08) P. nitidula Emery, 1888
09) P. nitidula Emery, 1888
10) P. indica Mayr, 1879
12) P. susannae Forel, 1886 (= P. obscurior Forel, 1886)

11: Probably certain species in the genus Nylanderia Emery, 1906.

Synonyms of host species.

- T. caespitum (Linnaeus, 1758) (= Formica caespitum Linnaeus, 1758)
- T. impurum (Förster, 1850) (= Myrmica impura Förster, 1850)
- P. megacephala (Fabricius, 1793) (= Formica megecephala Fabricius, 1793)
- P. megacephala (Fabricius, 1793) subsp. melancholica Santschi, 1912 was originally
described as P. punctulata Mayr, 1866 st. melancholica Santschi, 1912

Important literature.

Wilson, E. O.,
1971, “The Insect Societies.”
1984, “Tropical social parasites in the ant genus Pheidole, with an analysis of the
anatomical parasitic syndrome (Hymenoptera: Formicidae).” Insectes Sociaux,
vol. 31, nr. 3: 316-334.
Hölldobler, B. K., & Wilson, E. O.,
1990, “The Ants.”
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The extreme, workerless inquilines.

Beitragvon Teleutotje » Samstag 28. Januar 2017, 09:52

Extreme, Workerless Inquiline ants.

Ants: Probably one of the most important animal-groups on Earth. Together with wasps and bees they play some of the most important roles in ecosystems around the world. Without these three groups of insects, most animal- and plant-species will become extinct on this little globe in space in the near future. So remember them well: Ants - Formicidae, Wasps - Vespidae and Bees (including digger-wasps) – Apidae. And if you want to know much about them, be prepared to read a lot! Almost every conceivably down-to-earth lifestyle you can think of, somewhere one or other ant lives like that, and for the airborne lifestyles, go to the wasps and bees! Have a lifetime of fun to discover all these animals! And for the most specialized animals on earth, you must go to the ants and discover the species in the genera Teleutomyrmex and Anergates and a few other, mostly related, species!

The extreme, workerless inquilines.

The genus Teleutomyrmex was described in 1950 by Heinrich Kutter, based on ants discovered in Saas-Fee (a small town in the canton Wallis, Switzerland.) in 1949 and 1950. The species was named T. schneideri. Later, the species was also found in the French Alps and Pyrenees, the Spanish Pyrenees, in Turkmenistan and in a nearby place in the Swiss Alps. The type-meadow in Saas-Fee was destroyed between 1950 and 1971. A second species, T. kutteri, was described in 1990 by Alberto Tinaut based on animals from the Sierra Nevada, Spain.

The ants from the genus Teleutomyrmex are the most specialized ants on Earth. They are extreme, workerless inquilines that became ectoparasites. Let me explain.

- Parasite: An animal that is dependent on another species to survive. This dependence is temporary (during a certain period of its life.) or permanent.
- Social parasites: Social animals (like ants!) that are dependent on other social animals to survive. This can be temporary (during colony-foundation.) or permanent.
- Inquilines: Permanent social parasites among ants are also called inquilines.
- Workerless inquilines: The worker-caste, not needed by the inquilines, has disappeared. Only females/queens and males exist.
- Extreme, workerless inquilines: The females/queens and males have undergone some important morphological changes. Through these changes the ants are more adapted to their specialized way of life but, at the same time, they make sure that the ants can’t survive without their host. Some examples are: reduction of the mouthparts, development of appeasement-glands, over-development of the reproduction-organs, becoming weak and “soft”, males that become pupoid (show characteristic modifications that makes the male look “like a pupa”, e.g. yellowish color, downward curved gaster, big external genital plates,...),…
- Ectoparasites: Parasites that need to be carried around by their hosts. They are not capable to or have great difficulty with walking very short distances.

Edward Osborne Wilson, in 1971, wrote down a list with almost all the characters that determine social parasites and, in 1990, completed the list together with Berthold K. Hölldobler. In it 41 characters are listed that extreme, workerless inquilines can have. Not all those inquilines have all the characters but they have most of them. The ants of the genus Teleutomyrmex display 36 characters of the list but have also a few adaptations that are special for their ectoparasitic lifestyle.

Only around twelve ant species are known that are extreme, workerless inquilines and two of them, the Teleutomyrmex species, have become ectoparasites. Teleutomyrmex females/queens have, for example, unique morphological adaptations like the dorsoventrally compressed gaster that easily fit around the gaster of the host-queen. Also, the queens and males of Teleutomyrmex-species have the terminal tarsal segments of their legs adapted/modified to be able to grip firmly the body of queens and workers of the host species and are so almost completely unable to walk alone.

One remarkable fact is that the males of Teleutomyrmex still have rudimentary, unusable wings while the males of the other extreme, workerless inquilines have lost the wings completely. In all its other characteristics it is further evolved compared with the other species. Strange but true!

A peculiar taxonomic fact: The genera Anergates and Teleutomyrmex and the host-genus Tetramorium are closely related ant-genera belonging to the tribe (group of closely related genera.) Tetramoriini (now the Crematogastrini). This tribe is part of the subfamily Myrmicinae which also includes the genus Pheidole (in the tribe Pheidolini, now the Attini!). Only Nylanderia belongs to a different subfamily, the Formicinae. Most of the known social parasitic ants belong to these two subfamilies…

Some taxonomic problems in this group of specialized ants.

In 1950, William Steel Creighton placed Anergates friedlandi as a synonym of A. atratulus. Although he recognized certain morphological differences between the two species in 1934 when he described A. friedlandi, he based his 1950 decision on the speculation of William L. Brown Jr. that the host-species of both inquilines was the same (yes) and that the North American population wasn’t native to that continent (maybe). So, no morphological data but host-species distribution was used to establish the synonymy. A few myrmecologists still question the decision and wait for the ongoing genetic comparison of European and North American Anergates-samples.

The last few years some myrmecologists (like Alfred Buschinger) think that the morphological differences between Teleutomyrmex schneideri and T. kutteri are very minimal and question if T. kutteri should be placed as a synonym of T. schneideri. Most still think both deserve species status (clear morphological differences between the queens and the males of both species!) and, for the moment, both names stay as species names on record.

Paratrechina and related genera were reviewed on genera-level in 2010 and one of the results was the division of Paratrechina into a few related genera, including Nylanderia. Some of these genera and part of the genus Nylanderia are recently revised and Nylanderia from North America was revised also but without the inquilines.

Tetramorium and related parasitic genera underwent a very thorough genetic phylogenetic study by Matthias Sanetra and Alfred Buschinger in 2000. When you read the paper only two possibilities exists. The first one: Tetramorium, Anergates and Teleutomyrmex should be considered to be synonyms of Strongylognathus and all the species together form one big genus (as Ward et al., 2014, say!). The other one: Tetramorium should be divided in at least eight different genera, all standing together with the parasitic ones in one compact tribe. The authors of the article still can’t follow either of the possibilities. Who will take a decision?

Important literature.

Kutter, H.,
1968, “Die Sozialparasitischen Ameisen der Schweiz.”
Wilson, E. O.,
1971, “The Insect Societies.”
1984, “Tropical social parasites in the ant genus Pheidole, with an analysis of the
anatomical parasitic syndrome (Hymenoptera: Formicidae).” Insectes Sociaux,
vol. 31, nr. 3: 316-334.
Hölldobler, B. K., & Wilson, E. O.,
1990, “The Ants.”
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The extreme, workerless inquilines.

Beitragvon Teleutotje » Samstag 28. Januar 2017, 10:19

Now a more detailled review of Teleutomyrmex and Anergates.

Teleutomyrmex Kutter, 1950.
(= Tetramorium Mayr, 1855 or = Strongylognathus Mayr, 1853).

Teleutomyrmex schneideri Kutter, 1950.
(= Tetramorium inquilinum Ward, Brady, Fisher & Schultz, 2015,
replacement name for Tetramorium schneideri (Kutter, 1950), junior secondary homonym of Tetramorium schneideri Emery, 1898).

Teleutomyrmex kutteri Tinaut, 1990.
(No replacement name for Tetramorium kutteri (Tinaut, 1990), junior secondary homonym of Tetramorium semilaeve kutteri Santschi, 1927).

(For all: Combination in Tetramorium Mayr, 1855 by Ward, Brady, Fisher & Schultz, 2015).

Kutter, H., 1950, “Über eine neue, extrem parasitische Ameise. 1. Mitteilung.” Mitteilungen der Schweizerischen Entomologischen Gessellschaft, vol. 23, no. 2, p. 81-94.
- 14 pp., 23 figs. - [1950-08-10].
Stumper, R., 1951, “Teleutomyrmex schneideri Kutter (Hym. Formicid.). II. Mitteilung. Über die Lebensweise der neuen Schmarotzerameise.” Mitteilungen der Schweizerischen Entomologischen Gessellschaft, vol. 24, no. 2, p. 129-152.
- 24 pp., 7 figs. - [1951-07-20].
Brun, R., 1952, “Das zentralnervensystem von Teleutomyrmex schneideri Kutt. (Hym. Formicid.). III. Mitteilung.” Mitteilungen der Schweizerischen Entomologischen Gessellschaft, vol. 25, no. 2,
p. 73-86.
- 14 pp., 7 figs. - [1952-05-15].
Gösswald, K., 1953, “Histologische Untersuchungen an der arbeiterlosen Ameise Teleutomyrmex schneideri Kutter (Hym. Formicidae).” Mitteilungen der Schweizerischen Entomologischen Gessellschaft, vol. 26, no. 2, p. 81-128.
- 48 pp, 26 figs. - [1953-06-20].
Kutter, H., 1968 (“1969”), “Die sozialparasitischen Ameisen der Schweiz.” Neujahrsblatt herausgegeben von der Naturforschenden Gesellschaft in Zürich auf das Jahr 1969, vol. 171, (Ausgegeben am 31. Dezember 1968), p. 1-62.
- 62 pp., 19 figs. - [1968-12-31].
Tinaut, A., 1990, “Teleutomyrmex kutteri, spec. nov. A new species from Sierra Nevada (Granada, Spain).” Spixiana, vol. 13, no. 2, p. 201-208.
– 8 pp., 5 figs. – [1990-07-31].
Sanetra, M., Buschinger, A., 2000, “Phylogenetic relationships among social parasites and their hosts in the ant tribe Tetramoriini (Hymenoptera: Formicidae).” European Journal of Entomology, vol. 97, no. 1, p. 95-117.
- 23 pp., 6 figs. - [2000-04-15].
Tinaut, A., Ruano, F., Martínez, M. D., 2005, “Biology, Distribution and Taxonomic Status of the Parasitic Ants of the Iberian Peninsula (Hymenoptera: Formicidae, Myrmicinae).” Sociobiology,
vol. 46, no. 3, p. 449-489.
- 41 pp., 20 figs. - [2005-??-??]
Ward, P. S., Brady, S. G., Fisher, B. L., Schultz, T. R., 2015, “The evolution of myrmicine ants: Phylogeny and biogeography of a hyperdiverse ant clade (Hymenoptera: Formicidae).” Systematic Entomology, vol. 40, no. 1, (Article first published online: 23 July 2014), p. 61-81.
- 21 pp., 3 figs., 9 supporting files. - [online 2014-07-23 - print 2015-01-??].

Notes about nomenclature:

Seifert, B., Buschinger, A., Aldawood, A., Antonova, V., Bharti, H., Borowiec, L., Dekoninck, W., Dubovikoff, D., Espadaler, X., Flegr, J. , Georgiadis, C., Heinze, J., Neumeyer, R., Ødegaard, F., Oettler, J., Radchenko, A., Schultz, R., Sharaf, M., Trager, J., Vesnić, A., Wiezik, M., Zettel, H., 2016, “Banning paraphylies and executing Linnaean taxonomy is discordant and reduces the evolutionary and semantic information content of biological nomenclature.” Insectes Sociaux, vol. 63, no. 2, p. 237-242.
- 6 pp., 2 figs. - [online 2016-03-19 - print 2016-04 or 05-??]
Ward, P. S., Brady, S. G., Fisher, B. L., Schultz, T. R., “Phylogenetic classifications are informative, stable, and pragmatic: the case for monophyletic taxa.” Insectes Sociaux, vol. 63, no. 4, p. 489-492.
- 4 pp., 1 fig. - [online 2016-09-19 - print 2016-10 or 11-??]

A few suggested alternatives:

Tetramorium (formerly Teleutomyrmex) inquilinum Ward, Brady, Fisher & Schultz, 2015.
Tetramorium inquilinum Ward, Brady, Fisher & Schultz, 2015 (formerly Teleutomyrmex schneideri Kutter, 1950 but not Tetramorium schneideri Emery, 1898).
Tetramorium kutteri (Tinaut, 1990) (formerly Teleutomyrmex kutteri Tinaut, 1990 but not Tetramorium semilaeve kutteri Santschi, 1927)

Anergates Forel, 1874.
(= Tetramorium Mayr, 1855 or = Strongylognathus Mayr, 1853).

Anergates atratulus (Schenck, 1852).
(= Myrmica atratula Schenck, 1852,
also described as new by Schenck, 1853).
(= Tetramorium atratulum (Schenck, 1852)).
(= Tomognathus atratulus (Schenck, 1852), obsolete combination).
(= Anergates friedlandi Creighton, 1934, junior synonym of Anergates atratulus (Schenck, 1852) by Creighton, 1950, also cited as
Tetramorium friedlandi (Creighton, 1934)).
(combination in Tetramorium Mayr, 1855 by Mayr, 1855,
in Tomognathus Mayr, 1861 by Mayr, 1863,
in Anergates Forel, 1874 by Forel, 1874 and
in Tetramorium Mayr, 1855 by Ward, Brady, Fisher & Schultz, 2015).

Schenck, C. F., 1852. “Beschreibung nassauischer Ameisenarten.” Jahrbuch des Vereins für Naturkunde im Herzogthum Nassau, Wiesbaden, vol. 8, p. 1-149.
- 149 pp., 0 figs. - [1852-(12-31)].
Schenck, C. F., 1853, “Die nassauischen Ameisen-Species.” Stettiner Entomologische Zeitung,
vol. 14, p. 157-163.
- 7 pp., ?? fig. - [1853-05-??].
Schenck, C. F., 1853, “Die nassauischen Ameisen-Species. (Fortsetzung.).” Stettiner Entomologische Zeitung, vol. 14, p. 185-198.
- 14 pp., 0 fig. - [1853-06-(30)].
Forel, A., 1874, “Les fourmis de la Suisse. Systématique, notices anatomiques et physiologiques, architecture, distribution géographique, nouvelles expériences et observations de moeurs.” Neue Denkschriften der Allgemeinen Schweizerischen Gesellschaft für die Gesammten Naturwissenschaften, vol. 26, p. 1-452.
- 452 pp., 2 plates (37 figs.). - [1874-(12-31)].
Creighton, W. S., 1934, “Descriptions of three new North American ants with certain ecological observations on previously described forms.” Psyche (Cambridge), vol. 41, no. 4, p. 185-200.
- 16 pp., 0 figs. - [1934-12-(31)].
Creighton, W. S., 1950, “The ants of North America.” Bulletin of the Museum of Comparative Zoology, vol. 104, p. 1-585.
- 585 pp., 57 plates. - [1950-04-(30)]. In reality [1950-04-01].
Ward, P. S., Brady, S. G., Fisher, B. L., Schultz, T. R., 2015, “The evolution of myrmicine ants: Phylogeny and biogeography of a hyperdiverse ant clade (Hymenoptera: Formicidae).” Systematic Entomology, vol. 40, no. 1, (Article first published online: 23 July 2014), p. 61-81.
- 21 pp., 3 figs., 9 supporting files. - [online 2014-07-23 - print 2015-01-??].

Notes about nomenclature:

Seifert, B., Buschinger, A., Aldawood, A., Antonova, V., Bharti, H., Borowiec, L., Dekoninck, W., Dubovikoff, D., Espadaler, X., Flegr, J. , Georgiadis, C., Heinze, J., Neumeyer, R., Ødegaard, F., Oettler, J., Radchenko, A., Schultz, R., Sharaf, M., Trager, J., Vesnić, A., Wiezik, M., Zettel, H., 2016, “Banning paraphylies and executing Linnaean taxonomy is discordant and reduces the evolutionary and semantic information content of biological nomenclature.” Insectes Sociaux, vol. 63, no. 2, p. 237-242.
- 6 pp., 2 figs. - [online 2016-03-19 - print 2016-04 or 05-??]
Ward, P. S., Brady, S. G., Fisher, B. L., Schultz, T. R., “Phylogenetic classifications are informative, stable, and pragmatic: the case for monophyletic taxa.” Insectes Sociaux, vol. 63, no. 4, p. 489-492.
- 4 pp., 1 fig. - [online 2016-09-19 - print 2016-10 or 11-??]

This species is described and discussed in many articles and books.

Additional references.

Bolton, B., 1976, “The ant tribe Tetramoriini (Hymenoptera: Formicidae). Constituent genera, review of smaller genera and revision of Triglyphothrix Forel.” Bulletin of the British Museum (Natural History) (Entomology), vol. 34, p. 281-379.
- 99 pp., 73 figs. - [1976-10-28].
Emery, C., 1898, “Beiträge zur Kenntniss der palaearktischen Ameisen.” Öfversigt af Finska Vetenskaps-Societetens Förhandlingar, vol 20, p. 124-151.
- 28 pp., 4 figs. - [1898-(12-31)].
Kutter, H., 1968 ("1967"), “Liste sozialparasitischer Ameisen.” Archives. Institut Grand-Ducal de Luxembourg (n.s.), vol. 33, p. 201-210.
- 10 pp., 0 figs. - [1968-??-??].
Kutter, H., 1977, “Hymenoptera, Formicidae.” Insecta Helvetica. Fauna, vol. 6, p. 1-298.
- 298 pp., ?? figs. - [1977-(12-31)].
Kutter, H., 1978, “Hymenoptera, Formicidae.” Insecta Helvetica. Fauna, vol. 6a, unpaginated, illustr.
- 112 pp., ?? figs. - [1978-??-??].
Mayr, G., 1853, “Ueber die Abtheilung der Myrmiciden, und eine neue Gattung derselben.” Verhandlungen der Zoologisch-Botanischen Vereins in Wien, vol. 3, p. 387-394.
- 8 pp., 1 plate (5 figs.). - [1853-(12-31)].
Mayr, G., 1855, “Formicina austriaca. Beschreibung der bisher im österreichischen Kaiserstaate aufgefundenen Ameisen, nebst Hinzufügung jener in Deutschland, in der Schweiz und in Italien vorkommenden Arten.” Verhandlungen der Zoologisch-Botanischen Vereins in Wien, vol. 5,
p. 273-478.
- 206 pp., 1 plate (5 figs.). - [1855-(12-31)].
Mayr, G., 1861, “Die europäischen Formiciden. Nach der analytischen Methode bearbeitet.” Wien,
C. Gerold’s Sohn, 80 pp.
- 80 pp., 1 plate (37 figs.). - [1861-(12-31)].
Mayr, G., 1863, “Formicidarum index synonymicus.” Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien, vol. 13, p. 385-460.
- 76 pp., 0 figs. - [1863-(12-31)].
Santschi, F., 1927, “A propos du Tetramorium caespitum L.” Folia Myrmecologica et Termitologica, vol. 1, no. 4/5, p. 53-58.
- 6 pp., 0 figs. - [1927-02-(28)].
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The extreme, workerless inquilines.

Beitragvon Teleutotje » Samstag 28. Januar 2017, 12:45

Like you can see I'm one of the ant-people that don't follow Ward et al, 2014, for the synonymies of certain genera. I do mention them but only as info...

The next reply from me is a reworked discussion (e.g. removal from links to websites, no repeats where possible,...), based on a topic started on June 4, 2002 in The Ant Farm and Myrmecology Forum ( http://antfarm.yuku.com/topic/2188/Tech ... IyDZj8zWM- )... It is very technical and is about how far evolution can go... It combines ideas from me, J. Trager, A. Wild, Prof. Dr. A. Buschinger, and a few others.

For the Prof.: My first contact with you was in connection with this topic, mails from June 12, 2002!
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The extreme, workerless inquilines.

Beitragvon Teleutotje » Samstag 28. Januar 2017, 12:53

Technical Info.: Inquilines, evolution, & classification.

Extreme inquilines , workerless .

The males are pupoïd , with reduced or no wings , pale colored , gaster bend down and forward , big and visible genital parts , reduced mouthparts , .....
And the queens have their normal glands partly or greatly reduced , have specialized glands on head and gaster to attract host workers , have reduced mouthparts , are adapted to their specialized form of life , .....

Now , you can ask how far a queen and male ant can go in adapting to inquiline lifestyles !
Which bodyparts do they need to survive as a species and what is redundant ?
When are they still called ants and at what point are they becoming something else ?
Putting it different : how far can they go ?

On evolution and classification .

When are they still called ants and at what point are they becoming something else ?
Putting it different : how far can they go ?

Given that most taxonomists now define groups in a cladistic context , the highly derived inquiline parasites will always be considered ants , even if they grow to be 11 feet tall , have bright purple polka-dots , and play for the NBA .

That is , membership in a taxonomic group is determined based on common ancestry , and if the inquilines evolve out of the middle of the ants , they will still be considered ants by our current classification system no matter how much change they undergo .

Once one is the member of a group , one can never cease being a member , one can only add new designations to an ever-growing list of categories . Ants evolved from wasps , but they are still considered to be a type of wasp . So ants are wasps , ants are insects , ants are arthropods , ants are animals .

Of course , this has to do with how we classify things . As to how different these derived inquilines might eventually become , nobody has any idea . That question might never be answered .

So , ants will always be ants !
But how far can they evolve in the direction they are going ? When will they reach the end of the line ? How will they look at the point where they can't get anywhere further ? How will the snapshot look like at the point where they have to choose : stay like I am and survive or change a little bit and " Goodbye for ever ! " ...

These are hard questions , and without a time machine I'm not sure anyone could ever answer them . There probably is no hard-and-fast limit to the amount of change that an inquiline lineage will undergo . Neo-Darwinists think that there may exist one or several fitness optima at particular trait values for particular ecological conditions , such that an inquiline lineage reaching those trait values is maintained indefinitely by stabilizing natural selection , so long as the ecology of the system remains stable . But maybe the fate of ants like Teleutomyrmex will be determined by the fate of Tetramorium caespitum and Tetramorium impurum , the two host species . But as they change , Teleutomyrmex will also change and eventually disappear !

So somewhere at some time some equilibrium will change and then 1) extinction , 2) evolution back to a previous form , or 3) some new evolution ! But how far can an ant go ? Lets just for a moment consider one point : the antenna . How many funicular segments are minimum needed ? I think two ( with scapus : total antennal segment = 3 ) . But you can work this way with almost everything : more , less , bigger , smaller , change the form of certain structures , ..... And then my question becomes : How will it looks like , the most evolved ant ?
There is a standard definition for the Formicidae . Within that frame you have subfamilies , genera , species and subspecies , all with a description defining how they are ! But somewhere there must be an ( imaginary ? ) ant that fulfills the standard definition , that can live ( with or without help . ) and that is made of a minimum / is reduced to a minimum ! So , how will it be ?

Odd stuff to think about .

Now , if you think the evolution of inquiline ants is strange , think about the evolution of the most reduced form of life that human genetic material has produced : stem-cells , e.g. the HELA cell line .

If the human lineage can evolve into something sort of like a protist , it must be supposed that it is theoretically possible , at least for an ant lineage , to evolve into something just as similar .

But you'll never say when you see in nature a few ( say 5 ) cells together : " Oh look , an ant ! " . So our comparison with an artificial cell line isn't so good .

If the step from normal males to pupoïd males is so small , where are all the other ant males that passed that line ?
Also , if you look at the list in the beginning , except the mentioned Paratrechina , they are all Myrmicinae ! Why ?

And if you were to sequence the DNA of those 5 cells, and use the sequence data as your basis for identification , you *would* conclude that those cells were an ant if those cells evolved from ants ! This obviously conflicts with what we see with our eyes , of course, but which set of data do we use ?

Here is the basic question : Do we decide how to classify organisms based on what they look like ? Or do we classify organisms based on their patterns of evolutionary relationships ?

This was a long-standing debate among taxonomists for quite a while , now largely resolved in favor of classifications that reflect ancestry . What eventually tipped the debate in favor of using patterns of ancestry and away from similarity is the difficulty of getting people to agree on *which* sets of traits we use , if we are to classify based on outward similarity alone .

Let's use inquilines as an example . We think that one of the key defining traits of an ant are the fact that ants are social and have a worker caste . By our standard , none of the inquilines are ants anymore . In losing workers and co-operative social behavior , they've already crossed the line and have become non-ants . In contrast , you might think that the most important trait is morphological : ants have a constricted waist and elbowed antennae . By your standards , the inquilines are still ants , and will be so long as they retain these two traits .

Who is right ? We or you ? The answer is that neither of us is objectively right and neither of us objectively wrong . The decision to favor one trait over another is a subjective call that depends heavily on the person making the decision . There is no non-arbitary way to resolve the dispute . You can turn an ant into a non-ant merely by changing your mind as to which traits are most important in defining " Ant " .

The end consequence of using outward similarity to classify organisms is that the scientists who name things will inevitably adopt different standards , and our classification scheme becomes very unstable . Disputes arise about which traits are most important , and since this is a subjective judgement call , no data can possibly resolve them . Whether or not inquilines are classified as ants or not can change every other week , depending on who publishes most recently . This instability is bad for communication purposes .

The appeal of using ancestry alone to classify organisms has to do with the fact that it is non-arbitrary . If two scientists disagree about which classification is more correct , data can be gathered , an evolutionary genealogy inferred , and the issue decided based on the resulting evolutionary tree . Since for any group of organisms there is only one real history , tying our classifications to that history makes the classifications non-arbitrary , and more stable . Stable taxonomy means that group names are not constantly changing , and this is good for communication .

Sorry for this long explanation but we hope it helps you understand why our question : " How will the snapshot look like at the point where they have to choose : stay like I am and survive ore change a little bit and " Goodbye for ever ! " is very difficult to address . As we see it , there is no correct answer , and every answer we could give would tell us far more about our own subjective decisions about what an ant is than it says about the evolution of the inquilines .

If you are interested as to how different these lineages might eventually become , there is no known way to answer that question . The amount of change will depend on the future conditions that these lineages find themselves in , which in turn determines the type of natural selection that will act . Without a time machine to see the future , we don't see any way to provide a satisfying answer to our question ( Even though our question is very interesting ! ) .

Further thoughts on inquilines .

Inquilines in general are very poorly known . We have probably only described a fraction of the total number of species of inquilines . They can be difficult to collect .

It isn't surprising that most inquilines are Myrmicines . Even if the rate of emergence of inquiline lineages were equal in all ant subfamilies , there would be more Myrmicine inquilines simply on the basis that Myrmicines are the largest group of ants to begin with .

Even though the step from normal to pupoid males might be genetically easy to accomplish , there may be no reproductive advantage to having pupoid males . If this is the case , there would be no selection pressure to evolve pupoid males , and we'd expect the lineage to retain normal males so long as the selection stays the same . There may be some experiments that we could conduct to determine the extent to which natural selection might favor pupoid vs. non-pupoid males , and under what conditions selection would favor one group over another . We'd need to find a lineage that has both types of males , though , and that may not be easy.
It is possible you don't understand the question " where are all the other ant males that passed that line ? " But if you mean why don't free-living ants ever have pupoid males , the answer is sometimes they do ( They are seen occasionally, even in Formica , a non-myrmicine ! ) , but the trait never gets genetically fixed because it's maladaptive in a free-living , normally outbreeding ant ." where are all the other ant males that passed that line ? " But if you mean " where are all the other inquiline ant males that passed that line ? " If it is such an easy line to cross ( they say 2 mutations or so ! ) , there must be more inquiline males that crossed that line ? They are well protected in their host's nests , get what they need , so why not become pupoïd ? What reason prevents so many inquiline male ants to become pupoïd ? Pupoid males might lead to excessive inbreeding : since they are stuck in a single nest with queens who are in high probability their own sisters , most matings will take place between brothers and sisters . Over the long run , this excessive inbreeding could cause severe problems for their viability as harmful mutations are increasingly expressed in the female progeny . This is a big possibility .

Also , normal males can fly . They are much better able to spread their genes to new colonies and areas . Pupoid males can only spread their genes widely if the queens they mate with disperse . In a population of ants with both types of inquiline males , the normal males might be able to spread their non-pupoid genes more widely and more quickly . This way the normal male genes may remain abundant in the population .

It appears that most deviations from "normal" colony propagation can be explained by a decreased success of dispersal and solitary founding by solitary queens in certain types of habitats . Consequently , alternative reproductive strategies are found especially in those species , in which environmental conditions or a highly specialized way of life are thought to make solitary founding costly . Among the key factors , which determine the success of reproductive strategies , appear to be spatial and temporal distribution of habitats and the availability of nest sites .

But we also don't think inbreeding is a problem for inquilines. As far as known, most are obligate inbreeders and have been through the lethal bottleneck . When checked , most females ( even those with flightworthy males , e.g. Labauchena . ) are already fertile when collected from nests before flying . Also , having pupoid males may be adaptive because they do not eat , thus exerting less of a drain on the host colony , maximizing resources for female production , etc.

We think the reason pupoid males are not more common , i.e. why more have not " crossed the line " , has to do with genetic constraints . It may not take much genetic change to cause the development of pupoid males , but the population must possess the mutation in the first place , and this is a rare event . Normally inbreeding brings in the female the harmful and lethal mutations together ! There are many populations in nature that defy the general rule and habitually inbreed ( or go all the way and eliminate genetic variation completely by cloning themselves -- parthenogensis ! ) . The point is that once a population has survived through the problem of lethals and selction has eliminated them , it may go on just fine for a time with the more limited genetic variation remaining .
Coming back on a previous remark : The HELA cell line is an extreme example of how under the right conditions even the human genome can produce a very simplified phenotype . So why not an ant genome ?
DNA is the best standard to use in evolutionary research but it is not easy to use it in the field ! So at some moment ( if this hasn't been passed already . ) we can't define an ant morphological but must go to genetics . So ants are animals with A , B , ... , Y and Z combinations of genetic material ! Can't use this definition in some outback , miles from the nearest village ! Linnean version in the field , Genetic version in the lab !

Here are some questions we asked one of the big specialist on parasitic ants ,
Prof. Dr. Alfred Buschinger .


Is there somewhere a genetic definition about ants ?
Why belong most , or all , extreme , workerless inquilines to the Myrmicinae ?
How far can an inquiline ant go in reducing and loosing organs ?
How many mutations are needed to change a male ant into a pupoïd male ?
Are there genetic constrains on males to become pupoïd ?
Why aren’t more male inquiline ants pupoïd ?
Is there a reproductive advantage for pupoïd males , and has someone done some experiments about the influence of natural selection on the decision of becoming a pupoïd male or not ?
Which genetic and evolutionary principals act against or in favor of pupoïd males ( we have already against pupoïds 1) inbreeding with the accumulation of harmful and lethal mutations and 2) less widely and slower dispersion of their genes . ) ?
What are the evolutionary plus-points for pupoïd males ?

The big answers !

" In the following I will try to answer your questions as far as is possible , and also give a few comments to certain poits on the previous writing .

Is there somewhere a genetic definition about ants ?
I do not know of any genetic definition ( though , perhaps , I do not exactly understand what you mean with a genetic definition . ) .

Why belong most , or all , extreme , workerless inquilines to the Myrmicinae ?
A problem for me since about 1965 when I began studying parasitic ants . You may find some ideas , but no real answer , in a paper : Buschinger , 1990 : Sympatric speciation and radiative evolution of socially parasitic ants . - Heretic hypotheses and their factual background . Z. zool. Syst. Evolut.-forsch. 28 , 241-260 .

How far can an inquiline ant go in reducing and loosing organs ?
Nobody can tell . But have a look in a zoological textbook , for Crustacea , Cirripedia , Sacculina carcini . The larva of this parasitic species , a cypris characteristic for Cirripedia , injects its cellular content into the host , a crab . And the male transforms all its cells into sperm which is injected into the spermathecae of the female . Let's preserve our flora and fauna , wait another 10 million years or so , and see whether the extreme parasites of ants go a similar way ! - You know that the name "Teleutomyrmex" means the "ultimate ant" , because H. Kutter felt unable to imagine a further " parasitic degeneration " of an ant species . - Even an egg , a sperm cell , a larva , as any part of an organism still belong to the respective species . Some fossil species have been described , e.g. , after egg shells , some hominid species after a skull or a few bones .

How many mutations are needed to change a male ant into a pupoïd male ?
Absolutely unknown , but I guess its only a few . - Sanetra & Buschinger , 2000 : Phylogenetic relationships among social parasites and their hosts in the tribe Tetramoriini ( Hymenoptera : Formicidae ) . Eur. J. Entomol. 97 , 95-117 . In this paper we provide molecular evidence that both Teleutomyrmex and Anergates derive from Tetramorium , however are not closely related among each other , and also not with Strongylognathus . This means that all three have evolved separately from Tetramorium ancestors , and consequently such a transition to parasitic life habits and phenotypes probably do not need many mutations .

Are there genetic constrains on males to become pupoïd ?
Impossible to say . I guess that the term "pupoid male" has been misunderstood . What Emery meant was probably that these males , wingless and not black but yellowish-grey , appear somehow like pupae . In fact they do not at all behave like pupae : They live longer than ordinary ant males , crawl around very actively within the nest , and copulate nearly all the day long with every female they come across . ( Long ago we made a TV movie in Switzerland . The cameraman after a while remarked : " This are real sex athletes ! " ) .

Why aren't more male inquiline ants pupoïd ?
In fact , Anergates seems to be the only species with really pupoid males . Teleutomyrmex males are winged , though don't fly ( according to Kutter ( ? ) a high proportion of them was infested by nematodes ! ) . Males of parasitic Plagiolepis are sometimes wingless , but resemble more the gynes , hence were dubbed " gynaecoid " . - A number of Epimyrma species ( parasites of Leptothorax , slavemakers and " degenerate slavemakers " . ) mate inside the nests though both males and gynes are normally winged ( Buschinger , 1989 : Evolution , speciation , and inbreeding in the parasitic ant genus Epimyrma ( Hymenoptera , Formicidae ) . J. evol. Biol. 2 , 265-283 . ) .

Is there a reproductive advantage for pupoïd males , and has someone done some experiments about the influence of natural selection on the decision of becoming a pupoïd male or not ?
How to do such experiments ?? - Even if you could suggest a technique , there remains the problem that Anergates ( as well as most other inquilines ! ) are rare , and very difficult to rear in the lab . With Anergates I got a ( small ) F1 , with Teleutomyrmex nobody has succeeded as yet .

Which genetic and evolutionary principals act against or in favor of pupoïd males ( we have already against pupoïds 1) inbreeding with the accumulation of harmful and lethal mutations and 2) less widely and slower dispersion of their genes . ) ?
Inbreeding in ants is not a serious problem with respect to accumulation of lethal genes because these are mostly eliminated already with the haploid males ( a male either has the sound allele , or the lethal allele . In the latter case it dies before spreading the allele . ) . - In a number of nest-mating species inbreeding is not necessarily the consequence : Some of them , e.g. Anergates atratulus , often are polygynous , have several queens in the nest which may have different origin .
The real problem with inbreeding in hymenopterans is the sex determination . Homozygosity in the ( proably few ) sex determining genes causes diploid ( and usually sterile ) males . With Harpagoxenus sublaevis I once produced , with lab inbreeding , diploid and even a few triploid males ( one diploid male probably had produced diploid sperm ; we checked the chromosome numbers . ) . - In the nest-mating Epimyrma species ( they all are monogynous ! ) always brothers and sisters mate, but the inbred females nevertheless produce normal diploid gynes ( in some species also a few workers . ) and haploid males ( the latter in very low numbers , e.g. 5 males and 40-50 gynes may be in one nest . ) . I can only speculate ( and Ross Crozier has agreed . ) that this genus has evolved a somehow different sex determination system ( see also the paper Buschinger , 1989 mentioned above . ) .

What are the evolutionary plus-points for pupoïd males ?
Who can say ? - Perhaps they continue producing sperm during their adult life , other than ordinary ant males that hatch from the pupa with degenerate testes , having all their sperm stock in the vasa deferentia . An Anergates male thus could inseminate many more gynes than an ordinary male . The colony could spend less energy by rearing only a few males . But the hypothesis of prolonged sperm production has still to be experimentally proven .

I hope my comments will be somehow helpful also for the members of the antfarm forum !

A. Buschinger . "

After all this .....

Some little remarks :

Wing-less males of Cardiocondyla produce sperm all their life !

Dr. Buschinger seems to confirm much of what we have said on this matter , but also re-emphasizes repeatedly how much we do not or perhaps even can not know .....

As for the genetic definition of ants , perhaps another way to say this is to ask if there is a set of genetic markers that characterize all ants as a group ? Our guess is there is not , since the group is very ancient and some modern forms must have diverged significantly from the formicid " Ur-genome " .
It definitely bears noting that not very much is yet known about these inquiline ants . They are not logistically easy to work with , and they are not commonly encountered , so we wouldn't expect easy answers .

Hope we all learned a lot about how far we are and what we don't know ! Still a lot to investigate and a lot we probably never will succeed in ! Now we all need to do a lot of research on these interesting ants before .....

Postscript .

Answers of Prof. Dr. Alfred Buschinger were edited ( removal of a few references to some remarks earlier in the text . ) .
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Teleutotje
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" I am who I am , I think ... "
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Re: The extreme, workerless inquilines.

Beitragvon Merkur » Samstag 28. Januar 2017, 19:54

Dear Marc,

Sincere thanks for this comprehensive "rewiew"! - I continue in German which you understand very well, as I know. ;)
Diese Übersicht ist jedenfalls für alle äußerst wertvoll, die sich mit dem Phänomen "Sozialparasitismus" näher vertraut machen möchten. Man sieht im letzten (monumentalen!) Teil vom Sa Jan 28, 2017 1:45 pm, wie weit reichend die theoretischen Erwägungen gehen können. Manches, was wir 2002 im Yuku-Forum diskutiert haben, sieht heute etwas anders aus. Wobei ich nur indirekt, via Teleutotje, mit-diskutiert habe. Bin aber seinerzeit dann ins Yuku-Forum eingetreten.

Hier ein paar m. o. w. zusätzliche Bemerkungen:
Auffassungs-Unterschiede gibt es viele, besonders in der Taxonomie der Arten(-gruppen).
Ich habe inzwischen keine Zweifel mehr daran, dass die DNA-Analyse die sicherste Methode ist, Verwandtschaftsbeziehungen zu klären. Das war 2002 noch anders, als man von sehr vielen Arten nur Museumsexemplare und noch keine DNA-Sequenzen kannte.
Doch was steht einer solchen Klärung bei Sozialparasiten und Wirtsarten entgegen?

Ich habe den Eindruck, dass ein ganz wichtiger Faktor der Mangel an geeignetem Tiermaterial ist! Natürlich verfolge ich recht genau, ob und wo über neue
Funde solcher Sozialparasiten berichtet wird. Dabei fällt auf, dass man auch über Wiederfunde der lange bekannten und beschriebenen Arten nur sehr
wenig zu lesen bekommt. Und wenn eine Art in einem neuen Gebiet entdeckt wird, so wird oft nur über den Fund eines Einzeltieres berichtet.
Anscheinend fehlen die "Spezialisten", die in der Lage sind, gezielt an einer Fundstelle nach Völkern der Art zu suchen. Oder man hat einfach andere Interessen, und die seltenen Parasiten werden erst viel später bei der Auswertung von (Massen-)Aufsammlungen entdeckt.

Besonders hilfreich ist es, wenn es gelingt, die Parasiten gleich an Ort und Stelle zu identifizieren, etwa beim Blick in ein geöffnetes Nest der Wirtsart.
Dazu muss man natürlich zur richtigen Zeit suchen, etwa wenn junge Geschlechtstiere vorhanden sind. Man kann im Frühsommer oder Herbst Dutzende Tetramorium-Nester öffnen, und nichts weist auf die Anwesenheit von Anergates hin. Doch zur richtigen Zeit fallen die kleinen Gynen und die graugelben, dicklichen Männchen schon oben im Nest sofort auf. Hilfreich ist dann auch, wenn man weiß, dass normale geflügelte Geschlechtstiere im Tetramorium-Nest anzeigen, dass bestimmt keine Anergates darin ist. Weiterhin hilfreich ist die Kenntnis des Aussehens von Anergates-Puppen: Deutlich zu kleine Puppen mit Flügelanlagen sind von Anergates, oder vielleicht sogar von Teleutomyrmex! - So gibt es für etliche solcher Arten Indizien, die in keinem Bestimmungsschlüssel zu finden sind, und die man auch kaum in einer „hochwissenschaftlichen“ Veröffentlichung unterbringen kann.

Manchmal muss man Proben aus vielen Wirtsvölkern nehmen und im Labor zur Aufzucht ihrer Brut bringen. Oder man muss zahlreiche Völker komplett einsammeln und unter dem Binokular durchmustern. Ein Beispiel (auch wenn die Art nicht zu den "extremen Inquilinen" zu rechnen ist) stellt Leptothorax goesswaldi dar, über die ich gerade hier berichtet habe: Im Freiland sind die parasitischen Gynen mit bloßem Auge nicht zu identifizieren. So haben wir in zwei Tagen insgesamt 106 Völker der Wirtsart möglichst komplett eingesammelt. Bei der abendlichen Kontrolle der Sammelröhrchen unter dem Binokular fanden sich 16 Völker mit L. goesswaldi! – So etwas geht natürlich nur mit Arten, die kleine, leicht zugängliche Völker haben, und am besten mit außertropischen Arten in der Winterruhe.

Teleutomyrmex: Irgendwie bin ich nicht glücklich mit der Vorstellung, dass die Königin permanent auf der Tetramorium-Königin reitet, vgl. folgende Bilder!
Teleutomyrmex-queen.jpg
Teleutomyrmex schneideri Gyne einige Tage nach der Begattung, in einem Teil des Mutternestes (im Labor).
Teleuto 2 +TetrW-600 wiki.jpg
Tetramorium-Königin und Teleutomyrmex-Jungweibchen
Die fertilen Tel.- Gynen haben so dicke Bäuche, dass die ventrale Eindellung der Gaster keine Rolle mehr spielen kann. Vielleicht lassen sich junge Gynen auf jungen Tetramorium-Gynen zur Koloniegründung mittragen. Diskutiert wurde die Möglichkeit bereits, aber es fehlt ein konkreter Nachweis, etwa eine gemeinsame Koloniegründung mit einer Tetramorium-Königin. Man hat noch nie eine fliegende Teleutomyrmex-Jungkönigin gesehen, anders als im Falle von Anergates! – So vieles ist noch immer rätselhaft bei diesen Tierchen!

Mir fällt zu dem Thema noch die Gattung Plagiolepis ein, mit insgesamt vier beschriebenen Parasitenarten (plus ein paar unbeschriebenen), von denen nur P. grassei einige wenige eigene Arbeiterinnen hat. Auch diese Arten sind „spezialisiert“, indem sowohl Gynen als auch Männchen polymorph sein können, mit intermorphen sowie geflügelten Exemplaren. – Auch über diese Gruppe liest man seit einiger Zeit nichts Neues, d. h. dass sie wohl von keinem Ameisenforscher gesammelt werden. :roll:
So viel, oder wenig, erst mal im Moment.
MfG,
Merkur
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