Euglandina rosea (Férussac, 1821) Attacking Mesomphix globosus (MacMillan, 1940)

    Over the years this reporter has become intimately familiar with Euglandina rosea in the wild as well as those maintained in captivity. An impressive carnivore, the species appears to not be very fussy about its choice of prey - any snail (or sometimes small slug) will do which includes other Euglandina. However, it was noted that hungry Euglandina presented with Mesomphix globosus (MacMillan, 1940) [Globose Button] prey snails did not devour that species. The actual interaction between the two species was not monitored. To investigate further, an experiment was conducted in which the pictured hungry captive 67 mm. Euglandina rosea was presented with a much smaller Mesomphix as sustenance. The Euglandina immediately attacked and prepared to devour the Mesomphix but withdrew. After a series of quickly repeated similar attacks and withdrawals the Euglandina called it a day and crawled away from the Mesomphix leaving the specimen apparently unharmed - see (video): Euglandina rosea Rosy Wolfsnail vs. Mesomphix globosus Globose Button Snail.

    While it remains uncertain how the Mesomphix escaped what appeared to be impending certain death, another member of the genus, Mesomphix cupreus, is a known carnivore,* and Dourson ([2011]: 5) reported: "In Kentucky, species of the genus [sic] Haplotrema, Ventridens, and Mesomphix are documented omnivores, feeding on a variety of gastropods (Atkinson, 1998)." It's possible that the species has the ability to defend itself against attack, even by a fearsome large Euglandina. Some snail aficionados have reported receiving a nip from Mesomphix species snails. A well placed nip to an Euglandina by a Mesomphix may be sufficient to deter all but the most persistent Euglandina attackers. The bottom image shows the Mesomphix post attacks looking no worse for wear.

* Pilsbry (1946: 336) wrote: "according to Mr. John Walton, it feeds upon snails; fully one-third of the specimens found in July were 'devouring shell and animal, sometimes of its own species. but more frequently the young of Mesodon [sic] albolabris, M. thyroides [sic], M. sayii, and Triodopsis palliata."

Pilsbry, H.A., 1946. Land Mollusca of North America (north of Mexico) vol. 2 part 1. Academy of Natural Sciences, Philadelphia. vii + pp 1-520. Dec. 6.