Nutrition
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
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).