Coevolution in Family Formicidae

8/4/2019 Coevolution in Family Formicidae

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COEVOLUTION IN FAMILY

FORMICIDAE



COEVOLUTION

a change in the genetic composition of one species (orgroup) in response to a genetic change in another.

in the family Formicidae was varying from mutualisticassociations with a number of different organisms fromfungi to insects and plants.

http://biomed.brown.edu/Courses/BIO48/27.Coevolution.HTML



SPECIES-SPECIFIC ANT-PLANT MUTUALISM

One study on coevolution between ant and plantsfound the strongest evidence yet for reciprocaladaptation of morphological characters in a species-specific ant-plant mutualism.



Myrmecophyte - plant that lives in association with acolony of ants and possesses specialized organs inwhich the ants live

Prostoma - a small unlignified organ in plants locatedat the apex of the domatium in which symbiotic antsexcavate an entrance hole.



Each myrmecophyte in the genus Leonardoxa hasevolved a prostoma with a different shape.

Precise measurements on the prostomata of threerelated myrmecophytes, on their specific associatedants and on the entrance holes excavated by symbioticants at the prostomata were performed.



It was shown that a correspondence of the plant and anttraits forms a morphological and behavioural filter.

This can be a strong evidence for coevolution betweenthe dimensions and shape of the symbiotic ants and theprostoma in one of the three ant-Leonardoxa

associations .

(http://biblioteca.universia.net/html_bura/ficha/params/id/21682851.html).



ANCIENT QUADRIPARTITE SYMBIOSIS

between fungus-growing ants, their fungal cultivars,the fungal parasites that infect the fungal cultivars andthe bacteria used by the ants to control the growth of the parasites is one model example of coevolution

(Currie et al. 1999; Mueller 2002).



Ants - eat the fungi as their main food source;

Fungi - benefit through propagation by the ants;

Ants inoculate new gardens with fungi from older

gardens, such that specific fungal cultivars are passedfrom garden to garden within an ant lineage.

Bacteria – produce antibiotics which inhibit the growthof fungal parasites that infect the fungal cultivars tomaintain nearly pure cultures of vegetative mycelia(Currie et al. 1999).



Four main lineages of fungal cultivars are grown by the210 species of fungus-growing ant.

Three out of the four main cultivar lineages have thesame ancient evolutionary history as the ants that growthem and the parasites that infect the cultivars (Currieet al. 1999).



The fourth cultivar, grownonly by ants in the Apterostigma pilosum group,has not been identified, but it

has been predicted to havean evolutionary history that isdistinct from those of theother cultivars (Chapela et al.

1994; Currie et al. 1999).



LEAFCUTTER ANT-FUNGUS SYMBIOSIS

Leafcutter ants

feed on special structures called gongylidia.

actively cultivate their fungus;

feed them with freshly cut plant materials; and

maintain them free from pests and molds.

Fungi

grow only in the underground chambers of the ants’ nestand

produce gongylidia.



Ant tending fungus garden



Acromyrmex coronatus

Atta cephalotes



Atta texana - leafcutter ant nest



ANT - ACACIA MUTUALISM

Ant (13 Pseudomyrmex

species) - protect theplant from herbivory.

Acacia - feeds the antswith nectar and protein-rich Beltian bodies whileproviding living space forthe ants in hollow thorns.



Beltian Bodies

Pseudomyrmex ferrugineus



BELTIAN BODIES

http://botit.botany.wisc.edu/images/130/s

ymbiosis_images/Acacia/beltian_bodies.php?



Specific characters of the plant appear to have evolvedfor the maintenance of this mutualism:

swollen, ~ hollow thorns (= ant home);

extra-floral nectaries (=source of nectar outside the flower

[i.e., the usual location] providing ants with food);

leaflet tips = Beltian bodies (= 99% of solid food forlarval/adult ants)



Specific characters in the ant that have evolved for themaintenance of this mutualism:

defense against herbivores

removal of fungal spores from Beltian body break-point

(=prevents fungal pathogens from invading plant tissues) (Janzen 1966).



The main point is that there are traits in both the antand the acacia that are traits not normally found inclose relatives of each that are not involved in similarmutualisms: mutualistic traits have evolved for the

interaction in reciprocal fashion.



Myrmecochory

Seed dispersal by ants

Elaiosomes - fleshy structures that are attached to theseeds of many plant species.

Ants - take the seed to their nest and feed theelaiosome to their larvae.

After the larvae have consumed the elaiosome, the antstake the seed to their waste disposal area, which is richin nutrients from the ant frass and dead bodies, wherethe seeds germinate.



Afzelia africana

Stylophorum diphyllum

tbnh=74&tbnw=118&prev=/images%3Fq%3Delaiosomes%2Bimages&hl=tl&usg=__mtBY2SuCg66g2H5BwIipDMId73c=&ei=GiC-SYSCDZz47AOnoZjuBA&sa=X&oi=image_result&

http://sparkleberrysprings.com/



This type of symbiotic relationship appears to bemutualistic, as the plant benefits because its seeds aredispersed to favorable germination sites, and alsobecause it is planted (carried underground) by the ants.

Elaiosomes are said to have coevolved along with someant species.



REFERENCES:

Chapela, J. H., Rehner, S. A., Schultz, T. R. & Mueller, U. G. 1994. Evolutionary history of the symbiosis between fungus-growing ants and their fungi. Science 266: 1691-1694.

Currie, C. R., S cott, J. A., Summerbell, R. C. & Malloch, D. 1999. Fungus-growing ants useantibiotic-producing bacteria to control garden parasite. Nature 398: 701–704.

http://biblioteca.universia.net/html_bura/ficha/params/id/21682851.html

http://sparkleberrysprings.com/

http://www.myrmecos.net/antfungi.html

http://www.myrmecos.net/ants/pseudomyrmex.html

Janzen, D. H. 1966. Coevolution of mutualism between ants and acacias in CentralAmerica. Evolution 20:249-275.

Mueller, U. G. 2002. Ant versus fungus versus mutualism: ant–cultivar conflict and thedeconstruction of the attine ant–fungus symbiosis. Am. Nat. 160: S67–S98.

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Coevolution in Family Formicidae