Behavioral Ecology and Sociobiology

, Volume 59, Issue 6, pp 732–739 | Cite as

Independence, not conflict, characterizes dart-shooting and sperm exchange in a hermaphroditic snail

  • Ronald ChaseEmail author
  • Kristin Vaga
Original Article


Although the sexes are united in hermaphrodites, conflict can still occur because the male and female functions have separate interests. We examined the evidence for conflict in the mating system of the terrestrial snail Cantareus aspersus (formerly Helix aspersa) where sharp, calcareous darts are ‘shot’ during courtship. We predicted that the use of the dart would either reflect or create conflict and this would be evident in either the courtship behavior or the transference of sperm. Previous studies demonstrated that the dart functions after sperm transfer to increase sperm survival. Using detailed observations of mating snails, we examined the factors that determine dart shooting order, the behavioral responses after being hit by a dart, the accuracy of dart shooting, and the allocation of sperm resources. We found that each dart was shot independently, and each animal appeared to be interested only in getting off the best possible shot, probably one that penetrates deeply near the genital pore. There is no evidence of mating conflict. Every snail transfers sperm to its partner, and the size of the donation does not depend on the success or failure of either snail’s dart shot. Although the receipt of a dart does not appear to cause harm, it may produce indirect costs due to the partial loss of control over fertilization. We conclude that mating in C. aspersus is a partnership in which independent actors demonstrate unconditional reciprocity during courtship and sperm transfer.


Mating conflict Sexual conflict Courtship Cantareus aspersus Helix aspersa 



We thank Katrina Blanchard, Robert Hutcheson, Joris Koene and Heike Reise for their comments on the manuscript. Angus Davison kindly allowed us to see unpublished work. Funded by a grant to R. Chase and an Undergraduate Student Research Award to K. Vaga, both from the Natural Sciences and Engineering Research Council of Canada. This research complies with current laws in Canada.


  1. Adamo SA, Chase R (1988) Courtship and copulation in the terrestrial snail Helix aspersa. Can J Zool 66:1446–1453CrossRefGoogle Scholar
  2. Anthes N, Michiels NK (2005) Do “sperm trading” simultaneous hermaphrodites always trade sperm? Behav Ecol 16:188–195CrossRefGoogle Scholar
  3. Balaban PM, Chase R (1990) Stimulation of mesocerebrum in Helix aspersa inhibits the neural network underlying avoidance behavior. J Comp Physiol A 166:421–427CrossRefGoogle Scholar
  4. Baminger H, Locher R, Baur A (2000) Incidence of dart shooting, sperm delivery, and sperm storage in natural populations of the simultaneously hermaphroditic land snail Arianta arbustorum. Can J Zool 78:1767–1774CrossRefGoogle Scholar
  5. Baur B, Locher R, Baur A (1998) Sperm allocation in simultaneously hermaphroditic land snail Arianta arbustorum. Anim Behav 56:839–845PubMedCrossRefGoogle Scholar
  6. Chapman T, Arnqvist G, Bangham J, Rowe L (2003) Sexual conflict. Trends Ecol Evol 18:41–47CrossRefGoogle Scholar
  7. Charnov EL (1979) Simultaneous hermaphroditism and sexual selection. Proc Natl Acad Sci USA 76:2480–2484PubMedCrossRefGoogle Scholar
  8. Chase R (2002) Behavior and its neural control in gastropod molluscs. Oxford University Press, New YorkGoogle Scholar
  9. Chung DJD (1986) Initiation of growth of the first dart in Helix aspersa Müller. J Molluscan Stud 52:253–255CrossRefGoogle Scholar
  10. Chung DJD (1987) Courtship and dart shooting behavior of the land snail Helix aspersa. Veliger 30:24–39Google Scholar
  11. Colegrave N, Ruxton GD (2003) Confidence intervals are a more useful complement to nonsignificant tests than are power calculations. Behav Ecol 14:446–447CrossRefGoogle Scholar
  12. Davison A, Wade CM, Mordan PB, Chiba S (2005) Sex and darts in slugs and snails. J Zool (in press)Google Scholar
  13. Greeff JM, Michiels NK (1999) Sperm digestion and reciprocal sperm transfer can drive hermaphrodite sex allocation to equality. Am Nat 153:421–430CrossRefGoogle Scholar
  14. Hänggi C, Locher R, Baur B (2002) Intermating interval and number of sperm delivered in the simultaneously hermaphroditic land snail Arianta arbustorum (Pulmonata: Helicidae). Veliger 45:224–230Google Scholar
  15. Koene JM, Chase R (1998) Changes in the reproductive system of the snail Helix aspersa caused by mucus from the love dart. J Exp Biol 201:2313–2319PubMedGoogle Scholar
  16. Koene JM, Schulenburg H (2005) Shooting darts: co-evolution and counter-adaptation in hermaphroditic snails. BMC Evol Biol DOI 10.1186/1471-2148-5-25Google Scholar
  17. Landolfa MA (2002) On the adaptive function of the love dart of Helix aspersa. Veliger 45:231–249Google Scholar
  18. Landolfa MA, Green DM, Chase R (2001) Dart shooting influences paternal reproductive success in the snail Helix aspersa (Pulmonata, Stylommatophora). Behav Ecol 12:773–777CrossRefGoogle Scholar
  19. Leonard JL (1990) The hermaphrodite’s dilemma. J Theor Biol 147:361–372PubMedCrossRefGoogle Scholar
  20. Leonard JL (1992) The ‘love-dart’ in helicid snails: a gift of calcium or a firm commitment? J Theor Biol 159:513–521CrossRefGoogle Scholar
  21. Michiels NK (1998) Mating conflicts and sperm competition in simultaneous hermaphrodites. In: Birkhead TR, Møller AP (eds) Sperm competition and sexual selection. London, Academic, pp219–254Google Scholar
  22. Michiels NK, Newman LJ (1998) Sex and violence in hermaphrodites. Nature 391:647CrossRefGoogle Scholar
  23. Pomiankowski A, Reguera P (2001) The point of love. Trends Ecol Evol 16:533–534CrossRefGoogle Scholar
  24. Rogers DW, Chase R (2001) Dart receipt promotes sperm storage in the garden snail Helix aspersa. Behav Ecol Sociobiol 50:122–127CrossRefGoogle Scholar
  25. Rogers DW, Chase R (2002) Determinants of paternity in the garden snail Helix aspersa. Behav Ecol Sociobiol 52:289–295CrossRefGoogle Scholar
  26. Vindelov LL, Christensen IJ, Nissen NI (1983) A detergent-trypsin method for the preparation of nuclei for flow cytometric DNA analysis. Cytometry 3:323–327PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Department of BiologyMcGill UniversityMontréalCanada

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