As mentioned throughout this website this species of snail is carnivorous and therefore eats other speices of snails and sometimes its own, instead of plants like other herbivore snails.  The Haplotrema concavum has developed a way it can distinguish what it is trying to eat and if it should eat it.  When a Haplotrema concavum first approaches its prey, which is either another snail or snail egg, it identifies the prey with its labial pads and then crawls onto the prey (Fig. 1A) (Atkinson, 2000).  The initial reaction of the snail is to crawl on the prey, but during transport the snail predator latches onto its prey and drags it towards its anchored shell, moving the prey a distance equivalent to its size, which is a few millimeters to a centimeter (Fig. 1B) (Atkinso,1998).  Because the snail is so small, this process needs to be completed multiple times, and takes a couple minutes to drag its prey into a suitable place to eat it, which usually is somewhere dark and secluded, like under a rock, or in a hole it dug (Atkinson, 1998).  If the Haplotrema concavum  finds another snail to eat, it does the same thing as an egg, but uses its radula to puncture the snails shell and eat it (Atkinson, 1998). When an egg or young snail has been first manipulated, the carnivorous gives off a very different behavior compared to the acts that follow (Atkinson, 2000).  This allows the snail to not eat and prey right away in the open, but rather control its impulses and eat in solitude (Atkinson, 2000).  There are many different interpretations that can be deciphered from these interactions, the first being that the snail has established a new taste or odor the prey that creates a new behavior in the snail (Atkinson, 2000).  The second explanation could be after the initial contact the snail just responds differently to the  same the stimulus that originally made the snail crawl on top of its prey (Atkinson, 2000).  Another explanation could be that the change in the snail's behavior is just a pattern of egg/young snail manipulation and consumption, where the transport process is just a continuation of the initial stimulus contact (Atkinson, 2000).   The snail knows that there are predators in his environment that could eat it while it is enjoying its meal, or something could come take its meal.  This is why this species of snail developed its food manipulation method, so it can eat its food without being bothered.


Haplotrema concavum, were offered eggs and hatchlings of its own species and eggs and hatchlings of another species of snail, Anguispira alternata (Atkinson, 1997).  Based on the results of the experiment the Haplotrema concavum changed its feeding preference as it increased in size and what species of snail it most preferred, at times eating its own speices, but always had a stronger desire for eggs/hatchlings of other speices (Atkinson, 1997).  Snails aren't developed enough to have parental care or the highly developed nervous system to not take part in cannibalism.  It just has the basic functions of finding and eating food to survive.  As the snails grew larger and older they preferred to eat eggs less and less, becoming quite obvious when the snails were six to seven millimeters in length (Atkinson, 1997).  There is no exact proof, but evidence suggests that previous interaction with A. Alternata has made this speices of snail a preference to Haplotrema concavum (Atkinson, 1997).  This would mean that snails can learn from prior experiences and use this information they learned to help them in the future. The cannibalistic feeding by the Haplotrema concavum wasn't because it was starving or had no food source because some of them had just eaten eggs of the A. alternata, but just had the basic life function to eat and survive (Atkinson, 1997).