Fungal Ant Gardens as Incubators for Snake Eggs

Parental care in snakes is poorly documented. It has been known since the 18th century that female pythons will not only guard their eggs but warm them when the ambient temperature drops; female king cobras have been long known to build nests of decomposing vegetation for their eggs and stay nearby; and more recently maternal care in rattlesnakes has been observed. There are other examples scattered in the literature but perhaps most unexpected is the ancient scolecophidians show signs of parental care and since parental care is present in these snakes, the behavior should not be too surprising in the more modern snake lineages. Paleontologist Claude Hibbard discovered a nursery (or a communal egg laying site) of the New Mexico worm snake, Rena dissectus in the 1960’s.
A Liotyphlops albirostris egg on a colony of A. cf. goniodes.
Note that the workers have planted pieces of fungal garden on
the egg’s shell.

Recently Gaspar Bruner and colleagues report the dawn blind snake (family Anomalepididae) Liotyphlops albirostris depositing its eggs in the fungus gardens of the fungus-growing ant Apterostigma cf. goniodes.They found three snake embryos in the nest of the phylogenetically basal attine ant, which has relatively small nests. In an effort to determine if the ants could distinguish snake eggs from a snake-like egg made of a different material, the authors observed the behavioral responses of ants to natural and artificial snake eggs. They transferred the eggs from the nest to a sterile Petri dish and removed the fungal mycelium around the eggs using forceps. Then either a plasticine or natural egg (with the fungus removed), was placed on the top of the fungal garden. Using a stereomicroscope they observed the ants’ behavior toward the egg or the plasticine egg. They found worker ants repeatedly attended and groomed the snake eggs, but never observed the ants biting them. The ant workers took pieces of their fungus garden and planted them on the eggs, behavior very similar to what the workers do with ant eggs, larvae, and pupae in their fungus garden, as a means of controlling infections. When researchers removed the mycelial cover of an egg the ants completely recovered the eggs with fungal garden material and restored it to the original condition but did not attend or cover the artificial egg. Also, the ants spent substantially more time physically examining the snake egg than the artificial egg suggesting the ants were not simply responding to natural eggs as a foreign object. The entire article is available on line.

Citation 
Gaspar Bruner, Hermógenes Fernández-Marín, Justin C. Touchon, and William T. Wcislo, “Eggs of the Blind Snake, Liotyphlops albirostris, Are Incubated in a Nest of the Lower Fungus-Growing Ant Apterostigma cf. goniodes,Psyche, vol. 2012, Article ID 532314, 5 pages, 2012. doi:10.1155/2012/532314



Labels: , ,