scholarly journals Parasitic mites influence intra- and interpopulational variation in sperm length in a simultaneous hermaphrodite land snail (Gastropoda: Helicidae)

2014 ◽  
Vol 113 (4) ◽  
pp. 1036-1046 ◽  
Author(s):  
Ellen Haeussler ◽  
Denes Schmera ◽  
Bruno Baur
Keyword(s):  
Land Snail ◽  
Simultaneous Hermaphrodite ◽  
Sperm Length ◽  
Interpopulational Variation ◽  
Parasitic Mites

Sperm utilization in subadult and adult simultaneous hermaphrodite snails mating in the wild

2011 ◽  
Vol 89 (11) ◽  
pp. 1041-1049 ◽  
Author(s):  
Sandra Kupfernagel ◽  
Bruno Baur
Keyword(s):  
Sperm Competition ◽  
Egg Production ◽  
Shell Growth ◽  
Land Snail ◽  
Snail Species ◽  
Simultaneous Hermaphrodite ◽  
Young Females ◽  
Short Period ◽  
In The Wild ◽  
Previous Mating

In species with multiple mating and long-term sperm storage, males are expected to show a preference for mating with virgin and young females to reduce the risk of sperm competition. In various simultaneous hermaphrodite land snail species, sperm production precedes egg production by 2–4 weeks, resulting in a short period of protandric hermaphroditism before shell growth is completed. In a natural population, we collected copulating pairs of the simultaneous hermaphrodite land snail Arianta arbustorum (L., 1758) consisting either of two adults, of two subadults, or of one adult and one subadult snail, and determined the paternity of their hatchlings that emerged from subsequently deposited eggs. Adult snails used sperm received from subadult mating partners for egg fertilization in the same frequency as sperm from adults, indicating that subadult and adult snails do not differ in male function. Furthermore, an unfinished shell is not a reliable indicator for virginity, because 35% of the subadult individuals had already sperm stored from previous mating(s). Compared with adults, young individuals exhibited a lower risk of sperm competition, indicated by a higher last mate sperm precedence. However, subadult snails produced fewer eggs than adult snails, counteracting the evolutionary advantage of preferring a young partner with low sperm competition risk.

scholarly journals Intensity of parasitic mite infection decreases with hibernation duration of the host snail

Parasitology ◽  
2012 ◽  
Vol 139 (8) ◽  
pp. 1038-1044 ◽  
Author(s):  
E. M. HAEUSSLER ◽  
J. PIZÁ ◽  
D. SCHMERA ◽  
B. BAUR
Keyword(s):  
Land Snail ◽  
Mantle Cavity ◽  
Land Snails ◽  
Parasite Development ◽  
Limiting Factor ◽  
Host Snail ◽  
Arianta Arbustorum ◽  
Parasitic Mite ◽  
Parasitic Mites ◽  
High Elevations

SUMMARYTemperature can be a limiting factor on parasite development. Riccardoella limacum, a haematophagous mite, lives in the mantle cavity of helicid land snails. The prevalence of infection by R. limacum in populations of the land snail Arianta arbustorum is highly variable (0–78%) in Switzerland. However, parasitic mites do not occur in host populations at altitudes of 1290 m or higher. It has been hypothesized that the host's hibernation period might be too long at high elevations for mites and their eggs to survive. To test this hypothesis, we experimentally infected snails and allowed them to hibernate at 4°C for periods of 4–7 months. Winter survival of host snails was negatively affected by R. limacum. The intensity of mite infection decreased with increasing hibernation duration. Another experiment with shorter recording intervals revealed that mites do not leave the host when it buries in the soil at the beginning of hibernation. The number of mites decreased after 24 days of hibernation, whereas the number of eggs attached to the lung tissue remained constant throughout hibernation. Thus, R. limacum survives the winter in the egg stage in the host. Low temperature at high altitudes may limit the occurrence of R. limacum.

Determinants of female and male reproductive success in a simultaneous hermaphrodite land snail

2011 ◽  
Vol 82 (4) ◽  
pp. 707-715 ◽  
Author(s):  
Nicole Minoretti ◽  
Denes Schmera ◽  
Sandra Kupfernagel ◽  
Samuel Zschokke ◽  
Georg F.J. Armbruster ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Land Snail ◽  
Male Reproductive Success ◽  
Simultaneous Hermaphrodite
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