Trochulus hispidus crawling through water

I have taken few photos while a juvenile land snail Trochulus hispidus has been crawling through a very small water pool. Land snails are vulnerable to hyperhydration. But it has spent only about two minutes in the water. Maybe it did not affect its regulation of water much. Hydration is much less known in gastropods than dehydration. Maybe it did it for contact rehydration (“drinking” though the body wall) on that sunny summer day or maybe it has just overcome the pool because it just wanted to go that way. Nobody knows.

Trochulus_hispidus
Trochulus_hispidus_2
Trochulus_hispidus_3
Trochulus_hispidus_4
Trochulus_hispidus_5
Trochulus_hispidus_6
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Trochulus_hispidus_8
Trochulus_hispidus_9

I wish you happy and successful new year 2012. I wish you to overcome all difficulties and much more understanding from others.

 

References:
Barker G. M. (ed.) (2001) The biology of terrestrial molluscs. pages 159-163 and 467-468.

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Mating of Xerolenta obvia

Xerolenta obvia is a hygromiid land snail. As its distribution area is referred Pontic region, but it occurs from Asia Minor to the Baltic Sea and to eastern France.

 

It lives in open dry grassy habitats. It is xerophilic (drought-resistant) and thermophilic species (lives in relatively high temperatures). This species hibernates in winter and it aestivates during summer for few months.

 

Aestivating Xerolenta obvia:

Xerolenta_obvia_aestivating

A group of aestivating Xerolenta obvia:

Xerolenta_obvia_aestivating_2

Epiphragm of Xerolenta obvia:

Xerolenta_obvia_epiphragm

It is a hermaphrodite land snail. It means, that one snail specimen has both sexes. Snails tranfer its sperm during mating. Later cross-fertilization occur. After some time later it lays separated 7-95 uncalcified eggs in a single clutch.

 

They reach sexual maturity in one year or later. For example in one area in Greece they reach maturity in 8 months after egg was layed (7 months after hatching), but they die after egg laying in the age about 1 year. In another area of Greece they reach sexual maturity in 1.5 years after egg was layed (= 18 months) and they have lived 2 years. Other source refer to longevity 2-3 years.

 

In Mediterranean they are mating and egg laying in autumn only. In Central Europe they are mating and egg laying from late spring to to early summer. It is mating in October (in Greece) after the aestivation in only few days.

 

I have found photos of mating of this species neither in the literature nor on the internet. I have taken 5 snails from the locality shown above to home at 3rd August 2011 and the later day I have recored the mating of them. Photos are in chronological order, but they are showing the same position all the time:

 

4th August 2011 06:25

Xerolenta_obvia_mating_1
Xerolenta_obvia_mating_2

6:29

Xerolenta_obvia_mating_3

6:32

Xerolenta_obvia_mating_4

Video of mating of Xerolenta obvia (30 seconds at 06:32):

06:39

Xerolenta_obvia_mating_5

06:40

Xerolenta_obvia_mating_6

Video of the last six minutes of mating:

References:

 

Irikov A. & Mollov I. (2006). Terrestrial gastropods (Mollusca: Gastropoda) of the western Rhodopes (Bulgaria). pp. 753-832. In: Beron P.: Biodiversity of Bulgaria. 3. Biodiversity of western Rhodopes (Bulgaria and Greece) I.

 

Falkner G., Obrdlík P., Castella E. & Speight M. C. D. (2001). Shelled Gastropoda of Western Europe. München: Friedrich-Held-Gesellschaft, 267 pp.

 

Lazaridou M. & Chatziioannou M. (2005). Differences in the life histories of Xerolenta obvia (Menke, 1828) (Hygromiidae) in a coastal and a mountainous area of northern Greece. Journal of Molluscan Studies 71(3): 247-252. doi:10.1093/mollus/eyi032 abstract

 

(in Slovak) Lisický M. J. (1991). Mollusca Slovenska [The Slovak molluscs]. VEDA vydavateľstvo Slovenskej akadémie vied, Bratislava, 344 pp.

 

Species summary for Xerolenta obvia“. AnimalBase, last modified 22 March 2011, accessed 5 December 2011.