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Egg Grooming in Vallonia Snails — Anti-Parasite Defence or Trophic Behaviour?

Kuźnik-Kowalska E., Proćków M., Pląskowska E., Pokryszko B. M.

Polish Journal of Ecology

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2018

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Vol. 66, nr 1

64--69

EN

During laboratory studies on the reproductive biology of Vallonia pulchella and V. costata we observed an unusual behaviour in adults and juveniles of both species. The snails moved with their heads and radulae over the egg surface as if feeding. The examination of the egg shell revealed the presence of the fungus Arthrobotrys oligospora, which commonly occurs in the soil and has multiple lifestyles: it is known as a nematode pathogen, a saprophyte and a coloniser of plant roots. The extraordinary behaviour of Vallonia may be associated with the presence of mycelium on the egg surface. We hypothesise three possible explanations of egg grooming: (1) parental care, (2) trophic behaviour and (3) the infection can constitute a means of defence against nematodes, which are known to be predators of snails and slugs as well as their eggs. The removal of the fungus is not associated with overcrowding, but may be a selective advantage when combined with feeding.

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Land snails as indicators of soil humidity in Danubian woodland (SW Slovakia)

Cejka T., Hamerlik L.

Polish Journal of Ecology

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2009

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Vol. 57, nr 4

741-747

EN

Moisture along with available calcium content are the major environmental factors controlling species richness and composition of the terrestrial molluscan fauna. In the present study, we focused on snails in a floodplain forest and their response on humidity. We described the model of response and calculate the humidity optima of particular species if possible. Generalised linear model (GLM) combined with Poisson distribution was used to ch aracterise the change of species abundance along a humidity gradient. From 31 species tested, 21 have shown significant response to humidity. The majority of specie s tested had unimodal response, four species showed monotonic regression type. Based on their humidity optima, species distributed along a moisture gradient belonged to three main ecological groups: (i) mesohygrophilous woodland species living mostly in non-inundated areas with humidity optima below 4, (ii) hygrophilous, forest hygrophilous and euryhygric species with optima between 4 and 6 and (iii) strongly hygrophilous (polyhygrophilous) species with mois ture optima above 6. Estimated moisture preferences for Danubian floodplain woodland land snail fauna would be a useful tool in a longterm biological monitoring of changing moisture regime.

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Heavy metals content in shell, foot and liver gland of roman snail (Hleix pomatia) living in different environments

Stawarz R., Formicki G., Zakrzewski M.

Chemia i Inżynieria Ekologiczna

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2006

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Vol. 13, nr 1-2

133-137

EN

Heavy metal (Cd, Pb, Zn and Cu) accumulaton in organs of snail (Helix pomatia) living in wood eeosystems surrounding the nuclear power station at Bohunice, SK and coal power station Łęg in Krakow, PL bas been studied. We detected higher levels of the investigated metals in organs of snails living near the eoal plant. With only one exception; the content of zine were higher in foot and shell of snails from Krakow than in foot and shell snails from Bohunice, but the level of this metal was higher in the liver gland of snails living near nuclear plant. The highest content of lead was detected in liver gland of snails from Krakow (67.67 +- 22.25 ug/g d.m) the lowest in the foot of snails from Bohnice (16.93 +- 5.26 ug/g d.m). The highest cadmium level were detected in foot of snails living near coal plant (20.97 +- 4.52 ug/g d.m), and the lowest in the shell ofsnails from Bohunice; 3.45 +- 1.70 ug/g d.m. The highest level of copper was detected in the liver of snails from Krakow (132.02 +- 81.79 ug/g d.m), and the lowest in shell of snails from Bohunice (3.22 +- 1.68 ug/g d.m).

PL

Badano stopień kumulacji kadmu, ołowiu, cynku i miedzi w muszli, stopie i gruczole wątrobowym ślimaka winniczka (Helix pomatia) pochodzącego z dwóch różnych środowisk: z rejonu elektrowni atomowej Bohunice (Słowacja) oraz z elektrociepłowni węglowej "Łęg" w Krakowie. Stwierdzono większą zawartość zarówno ksenobiotyków, jak i pierwiastków biogennych w narządach ślimaków odłowionych w rejonie elektrowni węglowej. Wyjątkiem była zawartość cynku w gruczole wątrobowym; większa u ślimaków z rejonu Bohunic niż z Łęgu. Największą zawartość ołowiu stwierdzono w gruczole wątrobowym ślimaków z Krakowa (67,67 +- 22,25 ug/g s.m), zaś najmniejszą w stopie ślimaków z Bohunic (16,93 +- 5,26 ug/g s.m). Zawartość kadmu była największa w stopie ślimaków żyjących w okolicach elektrowni węglowej (20,97 +- 4,52 ug/g s.m), a najmniejsza w muszlach ślimaków z Bohunic (3,45 +- 1,70 ug/g s.m.). Największy poziom miedzi stwierdzono w wątrobie ślimaków z Krakowa, zaś naj niższy w muszlach ślimaków z Bohunic.