Interactions
Experiment: Interaction with other species
To test their interaction with another species that is often found in sympatric with Turbo undulatus, it was encouraged to right itself next to a sympatric test species. Using the test species to right itself would indicate that it does not avoid that species in the wild and could possibly interact with it.
Question 1: Do Turbo undulatus avoid other turbo undulates?
Question 2: Do Turbo undulatus avoid other shelled species?
Question 3: Do Turbo undulatus avoid other unshelled species?
All test species used in this experiment lives in sympatric with Turbo undulates in the reef crest and adjacent reefflat.
Hypothesis 1: They are often found together in clumps on the same coral boulder and thus, they do interact with each other in the wild and will use each other to right themselves in this experiment.
Hypothesis 2: They are often not found living in close proximity with other shelled organisms and thus may not have much interaction with them in the wild. They will not use the hermit crab, Dardanus lagopodes, to right.
Hypothesis 3: They are often not found living in close proximity with other non shelled organisms and thus may not have much interaction with them in the wild. They will not use the sea star, Echinaster luzonicus, or the black sea cucumber, Holothuria leucopsilota, to right.
Control: Turbo undulatus were placed on its dorsal side in an empty glass petri dish filled with seawater to watch it right.
Turbo undulatus righting itself in a glass petri dish
Treatment1: Turbo undulatus were placed on its dorsal side next to another species of Turbo undulatus in an empty glass petri dish filled with seawater to watch if it uses the neighboring Turbo undulatus to right. This experiment was replicated four times.
Turbo undulatus using another Turbo undulatus species to right 1
Turbo undulatus using another Turbo undulatus species to right 2
Result: The individual used its tentacles which is capable of chemoreception and mechanoreceptor to feel the shell of the neighboring Turbo undulatus. After it has a sense of the texture of the substrate beside it (through mechanoreceptor) and possibly the type of species beside it (through chemoreception), it protracts its muscular foot to attach on to the shell of the neighbor Turbo undulatus to right itself. The neighbor Turbo undulatus does not react or move.
Discussion: Turbo undulatus do interact with each other, thus, we can accept hypothesis 1. Tentacles probably play a role in chemoreception and mechanoreception in the righting process. The neighbor Turbo undulatus does not react or move. This further indicates that interaction between them is common in the wild.
Treatment 2: All four Turbo undulatus were placed on its dorsal side next to a hermit crab, Dardanus lagopodes, in an empty glass petri dish filled with seawater to watch if it uses the neighboring shelled invertebrate to right.
Results: Same behavior observed as in treatment 1. It uses its tentacles to sense and immediately sticks out its foot to attach and start the righting process. The hermit crab reacts to the increased weight of its shell by moving away but this does not adversely affect the capability of the snail to right.
Discussion: The use of the hermit crab to right indicates that as long as its tentacles senses a hard substrate, it will use it to right itself. However, the response of the hermit crabs to the snail’s attachment shows that this interaction between the two species is not a natural phenomenon in the wild. Thus, hypothesis 2 is accepted.
Treatment 3: All four Turbo undulatus were placed on its dorsal side next to a sea star, Echinaster luzonicus, in separate experiments, in an empty glass petri dish filled with seawater to watch if it uses the neighboring unshelled invertebrate to right.
Turbo undulatus interaction with a sea star
Results: Turbo undulatus avoided attaching its foot to the sea star after its tentacles has touched the arm of the sea star. It then waves its muscular foot around to try to find other stubtrata to attach to. The sea star responded in all four tests by moving away from the direction of the snail using its tube feet.
Discussion: Turbo undulatus avoids interaction with the sea star. This may be because its tentacles sensed a foreign semi hard texture of the sea star which was also slowly moving away. This contrasts the moving but familiar hard substrate of the hermit crab which resembles the hard substrate of the coral rubble they inhabit. Thus, it hesitated to attach its foot on the sea star. The flight reaction of the sea star strongly supports hypothesis 3 that two way interaction between Echinaster luzonicus and Turbo undulatus is absent on the reef.
Treatment4: All four Turbo undulatus were placed on its dorsal side next to a sea cucumber, Holothuria leucopsilota, in an empty glass petri dish filled with seawater to watch if it uses the neighbouring unshelled invertebrate to right.
Turbo undulatus interaction with a sea cucumber
Result: Same with the sea star. The turbo used its tentacles to feel the texture of the sea cucumber but did not protract its foot towards the sea cucumber to attach to it and start righting.
Discussion: Turbo undulatus avoided interaction with the sea star. The reason may be same as treatment 3 with the sea star. The texture of the sea cucumber is foreign to the snail and thus it did not attach its foot to the sea cucumber. Thus, hypothesis 3 can be accepted.
In summary, Turbo undulatus may interact with other shelled species (use them to right) but they do not use unshelled species to right in the wild. However, this is not conclusive that there is no interaction at all between Turbo undulatus and other sympatric unshelled invertebrates. It is only conclusive that Turbo undulatus is incapable of using unshelled substrata right, which rules out one of the many avenues of interaction. Further studies must be done to test other interactions between Turbo undulatus and sympatric species such as competition, predation, mutualism and commensalism.
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