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1
Content available Life cycle and population dynamics of Discus rotundatus (O.F.Muller, 1774) (Gastropoda: Pulmonata: Endodontidae)
100%
Kuznik-Kowalska E.
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nr 1
EN
The following life history traits of D. rotundatus (O. F. Müll.) were established based on field and laboratory observations: fully calcified eggs ca 1 mm in diameter, of a size correlated with the number of parent’s whorls; 1–11 eggs per clutch; 1–178 eggs per lifetime, in 1–36 clutches; incubation period 14–36 days; egg cannibalism with a strong preference for conspecific eggs; quick growth (33–35 days per whorl) prior to maturity and slow growth in mature snails, resulting from energy expenditure for egg-laying; sexual maturity at 5.5 whorls (2nd–3rd year of life); life span 2.5–3.5 years. Isolated individuals produce fewer eggs of lower viability than individuals kept in groups, they lay their eggs later and at a larger size. Most eggs in the laboratory arelaid in June, in thefie ld themaximum of there productivepe riod falls in July/August.
2
Content available Life cycle of Discus ruderatus (Ferussac, 1821) (Gastropoda: pulmonata: Endodontidae)
100%
Kuznik-Kowalska E.
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nr 1
EN
Life cycle of Discus ruderatus (Fér.) was studied in the laboratory, with occasional field observations. No courtship or copulation could be observed; uniparental reproduction is very rare. In the laboratory the eggs are laid in all months, with maximum in June/July and December/January, in the field the youngest age class appears in May. The eggs are laid on rotting timber; they are calcified, nearly sphaerical, ca. 1.5 mm in major diameter; the number of eggs per batch is 1–6 (mostly 3–4), with a total of 6–15 eggs in 2–5 batches per lifetime. The incubation period is 17–34 days, hatching is nearly synchronous; the hatching success is ca. 54%. The hatchlings have shells of 1.5–2.5 whorls; they consume their egg envelopes immediately after hatching. The egg cannibalism is prolonged into adult stage. The overall mean growth rate is 1 whorl per ca. 179 days (54 days per whorl till maturity, 487 days per whorl in mature snails). The snails reach maturity at slightly over 4 whorls (mature gametes present in the gonad), the mean life span is 580 days, the reproductive life constituting ca. 35% total life span. Life cycle parameters of three members of Discus are discussed comparatively.
3
Seasonal changes in the age structure of a land malacocenosis (Gastropoda), with notes on clustered distribution of selected species
100%
Kuznik-Kowalska E.
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nr 1-4
EN
Comparison of quantitative samples taken in consecutive seasons of the year in a forest malacocenosis in SW Poland revealed considerable changes in the snail density per unit area; the structure of the malacocenosis remained roughly constant throughout the year. Acicula polita (Hartm.), Columella edentula (Drap.), Discus perspectivus (Mühlf.), Alinda biplicata (Mont.) and Helicodonta obvoluta (O. F. Müll.) show aggregated distribution only during a part of the year.
4
Content available Life cycle and population dynamics of Discus perspectivus (Megerle von Muhlfeld, 1818) (Gastropoda: pulmonata: Endodontidae)
100%
Kuznik-Kowalska E.
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nr 4
EN
Life cycle and population dynamics of Discus perspectivus (Mühlf.) were studied in the field and in the laboratory. No courtship, copulation or uniparental reproduction could be observed. The eggs, laid in June, July and August on rotting timber are calcified, ellipsoidal, ca. 1 mm in major diameter; the number of eggs per batch is 1–9 (mostly 3–4), with a total of 17–33 eggs per individual per season. The incubation period is 24–35 days, hatching is nearly synchronous; the proportion of hatching eggs laid by individuals brought from the field is 51% (for eggs brought from the field 38.7%). The hatchlings have shells of 1.8–2.3 whorls; they consume their egg envelopes immediately after hatching. The egg cannibalism is prolonged into adult stage; only conspecific eggs are consumed; juveniles eat eggs of their own and alien batches. The growth rate in the laboratory is 1 whorl per 49–188 days (slower in the field); the growth is faster in juvenile and slower in mature snails. The snails reach maturity at slightly over 5 whorls (mature gametes present in the gonad), the life span is 173–849 days, the reproductive life constituting ca. 7% total life span. In the field juveniles hatch from June till October, with the maximum in August; till their first hibernation they reach 2.6–3.5 whorls and become mature in their second season to reproduce in the same or next year. The population density exceeds 50 m-2 in summer, and ranges from 25 to 30 m-2 during the remaining seasons. D. perspectivus shows aggregated distribution in August and October, in the remaining months the distribution is even. Some laboratory-born individuals have very much elevated spires and their shells become scalariform at the level of 5.3–5.75 whorls.
5
Content available An anomaly of the reproductive organs in Trochulus hispidus (Linnaeus, 1758) (Gastropoda: Pulmonata: Hygromiidae)
63%
Prockow M. , Kuznik-Kowalska E.
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nr 1
EN
A specimen of Trochulus hispidus from Buchenbach, Germany, had its male and female parts of thereproductive system completely separated. The female part lacked auxiliary organs. The male part opened into the genital atrium, but the vas deferens was blind-ended in a way precluding sperm transfer.
6
Content available Malacofauna of the Przemkow Landscape Park
63%
Kuznik-Kowalska E. , Prockow M.
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nr 1
7
Content available Petasina unidentata (Draparnaud, 1805) – a new species for the mollusc fauna of the Roztocze Upland (SE Poland)
63%
Prockow M. , Kuznik-Kowalska E.
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nr 4
8
Content available Selected aspects of reproductive biology of Zonitoides excavatus (Alder, 1830) (Gastropoda: Pulmonata: Gastrodontidae)
63%
Kuznik-Kowalska E. , Pokryszko B. M.
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nr 1
9
Content available Reproduction and growth of Xerolenta obvia (Menke, 1828) (Gastropoda: Eupulmonata: Geomitridae) in laboratory conditions
51%
Kuznik-Kowalska E. , Baran M. , Prockow M.
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nr 3
10
Content available Terrestrial gastropods of the nature reserve Stary Zagaj and the town of Skępe (Dobrzyńskie Lakeland). The malacocoenosis structure as an indicator of anthropogenic influence in north-central Poland
51%
Kuznik-Kowalska E. , Frasunkiewicz M. , Pokryszko B. M.
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2020
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tom 28
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nr 2
11
The influence of climate on shell variation in Trochulus striolatus (C. Pfeiffer, 1828) (Gastropoda: Hygromiidae) and its implications for subspecies taxonomy
51%
Prockow M. , Kuznik-Kowalska E. , Mackiewicz P.
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nr 2
EN
Trochulus striolatus is a land snail showing great morphometric variation in its shell, which is the basis for recognition of its subspecies. However, this variability can result from an influence of environment. To verify the possible effect of bioclimatic and spatial variables on the shell size and shape, we studied many samples collected from four biotic zones (lowland, submontane, montane and subalpine). Many of its shell features appeared significantly negatively correlated with a precipitation parameter and altitude, whereas positively correlated with temperature parameters. The shells were smaller at higher altitudes and in colder environment with greater precipitation. The reduced growth period can be an adaptive response to the shorter growing season in mountainous regions compared to lowland areas, where the longer season permits a longer growth resulting in larger mean adult body size. This conforms to the converse Bergmann's cline. The synergetic interactions between seasonality, temperature and moisture best explain the size variation in T. striolatus resulting from the influence of local environmental and/or climate factors. Therefore, there is no sufficient justification for subspecies recognition and the subspecific epithets for T. striolatus should be discarded.
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