Photo of the day (20): Aegopinella nitidula

Aegopinella nitidula is a land snail living in wet habitats. This specimen is from northern Bohemia. The proper determination requires dissection but another malacologist determined it in situ based on its appearance and detailed knowledge of local malacofauna. There are usually only informations about its shell and about its reproductive system available in books. Its shell is red-brown in color. The only information about a live snail is usually like this: The color of the body is dark.

So enjoy the photo of this snail:

Aegopinella_nitidula

Apical view:

Aegopinella_nitidula_2

According to tables in Falkner et al. (2001) feeding habits are like this: It prefer dead plants. It is sometimes carnivorous/saprophagous. It rarely eat also living algae and fungi.

I gave fresh leaves of Trifolium repens as a food source and a Trochulus hispidus as a prey for this snail. I was hoping that it will be enough for my AegopinellaAegopinella died after about 7-10 days but Trochulus survived in the same conditions. I am not sure if Aegopinella nitidula was eating those leaves and if it would eat those leaves after some time. It did not eat the Trochulus hispidus so I think that it can not predate an adult Trochulus hispidus that has approximatelly the same size as Aegopinella.

Your infomations about feeding habits of Aegopinella nitidula are welcomed.

References

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

(in Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. 2010: Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]. – Malacologica Bohemoslovaca, Suppl. 1: 1-37.

Photo of the day (19): Planorbis planorbis

Planorbis planorbis is very common freshwater snail in western part of Eurasia.

It holds its shell upside down and its shell is sinistral as in all other Planorbidae. Apertural view of a shell with a live snail in it:

Planorbis_planorbis_3

Dorsal view of a snail and umbilical view of its shell:

Planorbis_planorbis
Planorbis_planorbis_2

Apical view of the shell and foot of a snail. The sun was shining brightly on the snail so there are some internal anatomical features visible. (This one photo is unaltered, while there are adjusted levels on other photos.)

If I undersnad it correctly then there is clearly visible renal vein as a thick red-brown line inside the last whorl. The renal vein leads to the kidney (that starts with renal tube). I think, there is also air chamber visible. I think, that the dark line insie whorls is inestine, that is connected to the stomach (the most dark place in the penultimate whorl):

Planorbis_planorbis_5

There is visible a mantle border on the photo:

Planorbis_planorbis_4

A similar photo:

Planorbis_planorbis_6

References

There are anatomical images of the genus Gyraulus by Meier-Brook available. These images are also reproduced in other malacological books because it shows the whole anatomy of the animal (removed from the shell).

Meier-Brook C. 1983 “Taxonomic studies on Gyraulus (Gastropoda: Planorbidae)”. Malacologia 24(1-2): 1-113. page 30.

Some anatomical images exactly of Planorbis planorbis were made by Baker, but they are not clearly undestandable without detailed anatomical knowledge.

Baker F. C. 1945 The molluscan family Planorbidae. The University of Illinois Press, Urbana.

Could snakes with infrared sensing see snails at night?

or
How does a land snail look like in infrared photography?

Abstract

I have corroborated the hypothesis that Mollusca are poikilothermic. It is possible to detect snails with infrared camera, at least in some environmental conditions and especially if snails are moving.

 

Introduction

 

Some snakes, such as pit vipers (subfamily Crotalinae) and some pythons (family Pythonidae) and some boas (family Boidae), have a pit organ, a sensory organs for infrared radiation (IR). Therefore they can detect thermal radiation emmited by their prey and from their environment. True vipers (subfamily Viperinae) also may have less sensitive thermal radiation receptors (within supranasal sac). Dmitrijev (1988) hypothetized, that similar thermal organs have all snakes.

 

This is important for snakes, that are hunting at night. For example this Iwasaki’s Snail-eater (Pareas iwasakii, family Colubridae) movie 1, movie 2 was apprently filmed at night. Did it use eyes or sense of smell (Jacobson’s organ) or thermal organ (if it has any)?

 

If I was a snail-specilized snake with a proper thermal radiation sensory organ (I have no idea if such snakes exist), would it be possible to “see” snails at night?

 

Methods

I have taken photos with Flir 3 infrared camera:

Flir_3_infrared_cameraFlir_3_infrared_camera_2Flir_3_infrared_camera_3

Gastropods:

juvenile Cepaea hortensis with the shell width of 11.5 mm;

adult Cepaea vindobonensis with the shell width of 24 mm.

Results

Photos from the common camera are not from the exactly same moment because I can not take photos from two cameras simultaneously.

Infrared photos of a Cepaea vindobonensis on a plastic box placed on a cold floating floor:

Cepaea_vindobonensis_ir_bCepaea_vindobonensis_ir_aCepaea_vindobonensis_ir_c

Photo of a Cepaea vindobonensis on a plastic box:

Cepaea_vindobonensis

Another infrared photo and normal photo of a Cepaea vindobonensis on a plastic box:

Cepaea_vindobonensis_ir_2
Cepaea_vindobonesis_ir_2

Photos at the sunny day on another plastic box:

Cepaea_vindobonensis_ir_4
Cepaea_vindobonensis_4

Note the mucous track visible on the IR photo:

Cepaea_vindobonensis_ir_5
Cepaea_vindobonensis_5
Cepaea_vindobonensis_ir_6
Cepaea_vindobonensis_6

 

Cepaea_vindobonensis_ir_7Cepaea_vindobonensis_ir_8Cepaea_vindobonensis_ir_9
Cepaea_vindobonensis_7Cepaea_vindobonensis_8Cepaea_vindobonensis_9

 

Infrared photos of a juvenile on Cepaea hortensis on a cold floating floor:

Cepaea_hortensis_irCepaea_hortensis_ir_2Cepaea_hortensis_ir_3

A photo of the same specimen of juvenile on Cepaea hortensis on a cold floating floor:

Cepaea_hortensis_juvenile

Both snails on the same photo:

Cepaea_ir
Cepaea

Discussion

There are very few published information about infrared photography of marine and freshwater gastropods. I have found no infomations about infrared photography of land snails and slugs.

This infrared camera takes photos with resolution 240×240 pixels.

I think that there would be hardly possible to see gastropods smaller than 10 mm with this camera because of its low resolution.

References:

 

(in Czech) Dmitrijev J. 1988: Obojživelníci a plazi známí i neznámí pronásledovaní chránění. – Lidové nakladatelství, Praha. 168 pp. p. 54.

 

Krochmal A. R., Bakken G. S., & LaDuc T. J. (2004). Heat in evolution’s kitchen: evolutionary perspectives on the functions and origin of the facial pit of pitvipers (Viperidae: Crotalinae). – The Journal of Experimental Biology 207: 4231–4238.

Wikipedia contributors. Infrared sensing in snakes. – Wikipedia. accessed 30 May 2012

 

Masaki Hoso, Yuichi Kameda, Shu-Ping Wu, Takahiro Asami, Makoto Kato & Michio Hori 2010: A speciation gene for left–right reversal in snails results in anti-predator adaptation. – Nature Communications 1(Article number: 133). doi:10.1038/ncomms1133