Physiology of cold hardiness in cocoons of five earthworm taxa (Lumbricidae: Oligochaeta)


Earthworm cocoons are mostly found in the uppermost soil layers and are therefore often exposed to low temperatures during winter. In the present study, cocoons of five taxa of earthworms were investigated for their tolerance to freezing, melting points of cocoon fluids and dehydration of cocoons when exposed to a frozen environment. Embryos of the taxa investigated were freeze intolerant. The melting points of fully hydrated cocoon fluids were high (above −0.3°C) and thermal hysteresis factors were absent. Exposure to a frozen environment caused the cocoons to dehydrate drastically and dehydrated cocoons showed significantly lower super-cooling points than fully hydrated cocoons, reducing the risk of freezing for dehydrated cocoons. It is proposed therefore that the cold-hardiness strategy of the earthworm cocoons is based on dehydration upon exposure to subzero temperatures in the frozen environment. Cocoons of three surface-dwelling taxa, Dendrobaena octaedra, Dendrodrilus rubidus tenuis and Dendrodrilus rubidus norvegicus had lower supercooling points and survived frost exposure better than cocoons of two deeper-dwelling taxa, Aporrectodea caliginosa and Allolobophora chlorotica. One of the investigated taxa, D. r. norvegicus, was collected from a cold alpine habitat. However, it was not more cold hardy than the closely related D. r. tenuis collected from a lowland temperate habitat. D. octaedra was the most cold hardy taxon, its cocoons being able to withstand −8°C for 3 months and −13.5°C for 2 weeks in frozen soil.

This is a preview of subscription content, access via your institution.



dry weight


fresh weight


supercooling point


  1. Asahina E (1969) Frost resistance in insects. Adv Insect Physiol 6:1–49

    Google Scholar 

  2. Block W (1982) Cold hardiness in invertebrate poikilotherms. Comp Biochem Physiol 73A:581–593

    Google Scholar 

  3. Holmstrup M (1992) Cold hardiness strategy in cocoons of the lumbricid earthworm Dendrobaena octaedra (Savigny). Comp Biochem Physiol 10A:49–54

    Google Scholar 

  4. Holmstrup M, Hansen BT, Nielsen A, Østergaard IK (1990) Frost tolerance of lumbricid earthworm cocoons. Pedobiologia 34:361–366

    Google Scholar 

  5. Holmstrup M, Østergaard IK, Nielsen A, Hansen BT (1991) The relationship between temperature and cocoon incubation time for some lumbricid earthworm species. Pedobiologia 35:179–184

    Google Scholar 

  6. Hopp H (1947) The ecology of earthworms in cropland. Proc Soil Sci Am 12:503–507

    Google Scholar 

  7. Huhta V (1978) Mortality in enchytraeid and lumbricid populations caused by hard frosts. Proc Symp: “Adaptions of animals on winter conditions”. Moscow

  8. Lee KE (1985) Earthworms. Their ecology and relationships with soils and land use. Academic Press, Sydney

    Google Scholar 

  9. Lee RE (1991) Principles of insect low temperature tolerance. In: Lee RE, Denlinger D (eds) Insects at low temperature. Chapman and Hall, New York, pp 17–46

    Google Scholar 

  10. Oglesby LC (1969) Inorganic components and metabolism; ionic and osmotic regulation: Annelida, Sipuncula and Echiura. In: Florkin M, Scheer BT (eds) Chemical zoology, vol IV: Annelida, Echiura and Sipuncula. Academic Press, New York, pp 211–310

    Google Scholar 

  11. Satchell JE (1980) R worms and K worms: a basis for classifying lumbricid earthworm strategies. In: Dindal DL (ed) Soil biology as related to land use practises. Proc VII Int Coll Soil Zool, pp 848–864

  12. Schmidt-Nielsen K (1990) Animal physiology. Adaptations and environment, 4th edn. Cambridge University Press, Cambridge, UK

    Google Scholar 

  13. Stöp-Bowitz C (1969) A contribution to our knowledge of the systematics and zoogeography of Norwegian earthworms (Annelida: Oligochaeta: Lumbricidae). Nytt Mag Zool 17:169–280

    Google Scholar 

  14. Sømme L (1974) The overwintering of Pelophila borealis Payk. III. Freezing tolerance. Norsk Ent Tidsskr 21:131–134

    Google Scholar 

  15. Weast RC (1989) Handbook of chemistry and physics, 70th edn. CRC Press, Cleveland

    Google Scholar 

  16. Zachariassen KE (1985) Physiology of cold tolerance in insects. Physiol Rev 65:799–831

    Google Scholar 

Download references

Author information



Rights and permissions

Reprints and Permissions

About this article

Cite this article

Holmstrup, M. Physiology of cold hardiness in cocoons of five earthworm taxa (Lumbricidae: Oligochaeta). J Comp Physiol B 164, 222–228 (1994).

Download citation

Key words

  • Cold hardiness
  • Dehydration
  • Freeze-intolerance
  • Vapour pressure
  • Earthworm cocoons