How does Oxychilus draparnaudi eat

Finally I have taken some photos of Oxychilus draparnaudi feeding on Trochulus hispidus after two months and half of keeping it.

I have taken the first photo on 15 October 10:34 AM and it stopped feeding on 10:52 AM. Although it is referred as a nocturnal animal, I was glad to see it feeding on daylight. It was sunny day, so taking photos was not difficult.

The first photo shows the foot, because it was feeding on the transparent lid of the terrarium. The predator was holding the whole of its prey when it was upside down.

Oxychilus_draparnaudi_feeding_01

Then I have removed the lid and rotated the lid to take these photos:

Oxychilus_draparnaudi_feeding_02
Oxychilus_draparnaudi_feeding_03
Oxychilus_draparnaudi_feeding_04
Oxychilus_draparnaudi_feeding_05

First photos immeditelly after the feeding:

Oxychilus_draparnaudi_after_feeding_01Oxychilus_draparnaudi_after_feeding_02Oxychilus_draparnaudi_after_feeding_03

Usually after the feeding process are shells empty and clean. I have probably distrubed its feeding process, because it seems that it have eaten the body of the first 3/4 of the first whorl only. The same shell of Trochulus hispidus still contain some material inside:

Trochulus_hispidus_shell

Open data:

continuously updated spreadsheet with data what Oxychilus draparnaudi have eaten.

 

How does Oxychilus hunt?

I wanted to see how the predaceous snail Oxychilus draparnaudi hunts and eats its prey. It is called to be typical predaceous species. But after 10 days of keeping it at home I have not seen it hunting yet.

Diary:
3rd August – I have collected the snail Oxychilus draparnaudi (shell width 7.5 mm). Locality: Olomouc, Czech Republic.

Oxychilus_draparnaudi_01

4th August – no food

5th August – added 3 Trochulus hispidus. They have cucumber as a food source. Even when the predator was at least one day without the food and its prey has been crawling on the predator’s body, it has not been hunting them during the day.

Oxychilus_draparnaudi_02

6th August – found Trochulus hispidus (shell width 4.0 mm) eaten

7th August – found Trochulus hispidus (shell width 5.5 mm) eaten at 9:01 and I have taken the photo of Oxychilus above the empty shell.
–  added 6 Trochulus hispidus
– added 2 adult Laciniaria plicata. I have no idea if it will be able to eat them.

Oxychilus_draparnaudi_03

8th August – found Trochulus hispidus (shell width 5.0 mm) eaten

9th August – found Trochulus hispidus (shell width 3.5 mm) eaten

10th August – nothing

11th August – found Trochulus hispidus (shell width 3.5 mm) eaten

12th August – nothing

13th August – nothing, measured Oxychilus draparnaudi (shell width is still 7.5 mm)

Results:
All my controls when I have found empty shells, were during the day, but the Oxychilus draparnaudi is nocturnal. Some controls were at night.
It have eaten 5 snails during 10 days.
I found no damage on shells of the eaten Trochulus and shells were completely clean inside (but with water).

Any hints how to see it hunting?

Oxychilus_draparnaudi_04