Post by apple on Dec 28, 2005 18:21:14 GMT
Waking and cleaning
As night falls the snails show signs of movement. There is a slow extension of the head and
partial eversion of tentacles. The anterior foot spreads a little on to the substratum. Although
little further movement may be seen for the next 30-60 min the animal is, nevertheless,
becoming active. Dorsal body waves (see p. 178) pass over the upper surface of the foot, the
collar, and the shell lip, before extending the collar to enfold the lip. There is frequent slow
fidgeting - withdrawal of the collar, and further cleaning of the shell lip - before the latter is
finally settles in the collar groove. The behaviour is strongly reminiscent of a cat cleaning
itself although the movements are much slower.
Cleaning should remove only the excessively polluted soil and food debris. Hygienically
clean tanks lead to cessation of feeding and reproduction, and ultimately to death of the snails
(see p. 177). A tendency towards slum conditions has to be aimed at, especially in the case of
A. panthera.
(d) Movement and feeding
When the animal has finished cleaning itself, it extends its head and foot and ambulation
commences, the dorsal body waves now being more powerful. Shortly after this a snail may
cease ambulation, its head being slowly lowered to the soil and then raised again. The process
is repeated a number of times and the soil below the head is ingested, leaving a shallow
depression that is wet from the snail's activities - apparently due to secretion that
accompanies the dorsal body waves. Ambulation may then recommence, the snail may
delicately examine a piece of apple with its anterior tentacles, its down-turned optic tentacles
and with its lips. It may now commence to feed, its activity being accompanied by powerful
and rapid dorsal body waves that bring a watery secretion from the external surface of the
head and cervical region into the feeding area, There is some evidence for suggesting that
each snail may have a cycle of feeding activities, viz. the ingestion and communition of food
that is then defecated without, or with very little digestion; the ingestion of soil - and some
food - followed by digestion and defecation; and, finally a period (one night) of little intake
of food followed by a day when the faecal string consists of material from the digestive
gland. There may be a 3-day cycle, that raises problems in the feeding of these animals. Also raises the question of the animal's possible need for regular ingestion of soil flora and
fauna together with rotting food material. In one useful but hazardous experiment a vivarium
was provided with double-sterilized soil, all surface soil and faeces were removed 3 times
weekly and the loss replaces with more sterilized soil. The first sign of trouble was a
cessation of oviposition in a formerly actively reproducing population of mixed ages. In 3
weeks the snails then ceased to feed and became lethargic and, in the following month, 13 out
of 24 snails died. At this point the experiment was terminated!
«The Life of Achatinidae in London»- R. H. Nisbet
As night falls the snails show signs of movement. There is a slow extension of the head and
partial eversion of tentacles. The anterior foot spreads a little on to the substratum. Although
little further movement may be seen for the next 30-60 min the animal is, nevertheless,
becoming active. Dorsal body waves (see p. 178) pass over the upper surface of the foot, the
collar, and the shell lip, before extending the collar to enfold the lip. There is frequent slow
fidgeting - withdrawal of the collar, and further cleaning of the shell lip - before the latter is
finally settles in the collar groove. The behaviour is strongly reminiscent of a cat cleaning
itself although the movements are much slower.
Cleaning should remove only the excessively polluted soil and food debris. Hygienically
clean tanks lead to cessation of feeding and reproduction, and ultimately to death of the snails
(see p. 177). A tendency towards slum conditions has to be aimed at, especially in the case of
A. panthera.
(d) Movement and feeding
When the animal has finished cleaning itself, it extends its head and foot and ambulation
commences, the dorsal body waves now being more powerful. Shortly after this a snail may
cease ambulation, its head being slowly lowered to the soil and then raised again. The process
is repeated a number of times and the soil below the head is ingested, leaving a shallow
depression that is wet from the snail's activities - apparently due to secretion that
accompanies the dorsal body waves. Ambulation may then recommence, the snail may
delicately examine a piece of apple with its anterior tentacles, its down-turned optic tentacles
and with its lips. It may now commence to feed, its activity being accompanied by powerful
and rapid dorsal body waves that bring a watery secretion from the external surface of the
head and cervical region into the feeding area, There is some evidence for suggesting that
each snail may have a cycle of feeding activities, viz. the ingestion and communition of food
that is then defecated without, or with very little digestion; the ingestion of soil - and some
food - followed by digestion and defecation; and, finally a period (one night) of little intake
of food followed by a day when the faecal string consists of material from the digestive
gland. There may be a 3-day cycle, that raises problems in the feeding of these animals. Also raises the question of the animal's possible need for regular ingestion of soil flora and
fauna together with rotting food material. In one useful but hazardous experiment a vivarium
was provided with double-sterilized soil, all surface soil and faeces were removed 3 times
weekly and the loss replaces with more sterilized soil. The first sign of trouble was a
cessation of oviposition in a formerly actively reproducing population of mixed ages. In 3
weeks the snails then ceased to feed and became lethargic and, in the following month, 13 out
of 24 snails died. At this point the experiment was terminated!
«The Life of Achatinidae in London»- R. H. Nisbet