Some autecological data on the Urodeles of SardiniaVoesenek, L.A.C.J.; van Rooy, P.T.J.C.; Strijbosch, H.
doi: 10.1163/156853887x00081pmid: N/A
AbstractIn the spring of 1984 an ecological investigation on the endemic salamanders Hydromantes genei flavus and Euproctus platycefihalus was carried out in eastern Sardinia. The investigation was focussed on natural population sizes and densities. The Sardinian cave salamander was found to occur in two clearly distinct habitats, viz. humid holm oak forests and limestone caves. The density found in the forests was 300/ha and 98 ± 7 individuals were found in one cave. The Sardinian brook salamander was found in a habitat not reported before, viz. a stagnant mountain lake. There the animals were rather robust, and a neotenic specimen was captured.
Some autecological data on the Urodeles of SardiniaVoesenek, L.A.C.J.; Strijbosch, H.; van Rooy, P.T.J.C.
doi: 10.1163/156853887X00081pmid: N/A
<jats:sec><jats:title>Abstract</jats:title><jats:p>In the spring of 1984 an ecological investigation on the endemic salamanders Hydromantes genei flavus and Euproctus platycefihalus was carried out in eastern Sardinia. The investigation was focussed on natural population sizes and densities. The Sardinian cave salamander was found to occur in two clearly distinct habitats, viz. humid holm oak forests and limestone caves. The density found in the forests was 300/ha and 98 ± 7 individuals were found in one cave. The Sardinian brook salamander was found in a habitat not reported before, viz. a stagnant mountain lake. There the animals were rather robust, and a neotenic specimen was captured.</jats:p>
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Random mating by size in a population of common toads (Bufo bufo)Höglund, Jacob; Robertson, Jeremy G.M.
doi: 10.1163/156853887x00108pmid: N/A
AbstractThe mating system of a population of individually marked common toads (Bufo bufo) was studied during two years at a pond on the island Öland, southern Sweden. The mating system can be described as explosive breeding with scramble competition for mates. Males outnumbered females by approximately 2:1 and competed for the possession of females by guarding them prior to spawning and by displacing already paired males. Data on displacement patterns showed that smaller males were displaced more often than larger males. However, successful males were not larger than the male they displaced. Furthermore, thc mean size of spawning males was not different from the population mean and the size distribution of spawning males did not differ from the size distribution expected by chance. No size assortion could be detected among spawning pairs. Female fecundity showed a strong correlation with increasing body size. Males of all sizes showed capability of fertilizing all eggs of any female. Females apparently did not choose their mates. Though males would enhance their reproductive success by mating with large and more fecund females, this scenario was probably hampered due to a short breeding season and an operational sex ratio close to 2: 1.
Random mating by size in a population of common toads (Bufo bufo)Robertson, Jeremy G.M.; Höglund, Jacob
doi: 10.1163/156853887X00108pmid: N/A
<jats:sec><jats:title>Abstract</jats:title><jats:p>The mating system of a population of individually marked common toads (Bufo bufo) was studied during two years at a pond on the island Öland, southern Sweden. The mating system can be described as explosive breeding with scramble competition for mates. Males outnumbered females by approximately 2:1 and competed for the possession of females by guarding them prior to spawning and by displacing already paired males. Data on displacement patterns showed that smaller males were displaced more often than larger males. However, successful males were not larger than the male they displaced. Furthermore, thc mean size of spawning males was not different from the population mean and the size distribution of spawning males did not differ from the size distribution expected by chance. No size assortion could be detected among spawning pairs. Female fecundity showed a strong correlation with increasing body size. Males of all sizes showed capability of fertilizing all eggs of any female. Females apparently did not choose their mates. Though males would enhance their reproductive success by mating with large and more fecund females, this scenario was probably hampered due to a short breeding season and an operational sex ratio close to 2: 1.</jats:p>
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Notes on nesting and parental care in Caiman crocodilus crocodilus in northern Suriname and an analysis of crocodilian nesting habitatsOuboter, Paul E.; Nanhoe, Lurly M.R.
doi: 10.1163/156853887x00117pmid: N/A
AbstractCaiman c. crocodilus constructed nests on small elevations in swamps during the long rainy season (May-July). Eggs were buried just beneath ground level and in addition covered by a small mound of dry leaves. This nest type is intermediate between the hole-type and the mound-type nest. Hatching occurred from the beginning until midway into the long dry season. One of two egg-containing nests studied was destroyed by predators. In the other nest 18 of 28 eggs hatched, which coincides with estimates based on pod sizes and estimated mean clutch sizes. Hatchlings stayed together (sometimes associated with second year caimans) for up to 18 months. Most of these pods were attended by an adult caiman for about seven months, until the beginning of the long rainy season. The sex ratio of newborn young was 0.5, but some pods seemed to consist of one sex only (sex ratio being 0 or 1). These results are compared with data on other populations of C. crocodilus and other crocodilians. In general there is a correlation between the nest type used and the nesting season; hole-nesting species nest in the dry season, whereas mound-nesting species usually nest in the rainy season. Nesting in the dry season by mound-nesting species occurs and possibly can be explained by avoidance of competition with sympatric moud-nesting species.
Notes on nesting and parental care in Caiman crocodilus crocodilus in northern Suriname and an analysis of crocodilian nesting habitatsOuboter, Paul E.; Nanhoe, Lurly M.R.
doi: 10.1163/156853887X00117pmid: N/A
<jats:sec><jats:title>Abstract</jats:title><jats:p>Caiman c. crocodilus constructed nests on small elevations in swamps during the long rainy season (May-July). Eggs were buried just beneath ground level and in addition covered by a small mound of dry leaves. This nest type is intermediate between the hole-type and the mound-type nest. Hatching occurred from the beginning until midway into the long dry season. One of two egg-containing nests studied was destroyed by predators. In the other nest 18 of 28 eggs hatched, which coincides with estimates based on pod sizes and estimated mean clutch sizes. Hatchlings stayed together (sometimes associated with second year caimans) for up to 18 months. Most of these pods were attended by an adult caiman for about seven months, until the beginning of the long rainy season. The sex ratio of newborn young was 0.5, but some pods seemed to consist of one sex only (sex ratio being 0 or 1). These results are compared with data on other populations of C. crocodilus and other crocodilians. In general there is a correlation between the nest type used and the nesting season; hole-nesting species nest in the dry season, whereas mound-nesting species usually nest in the rainy season. Nesting in the dry season by mound-nesting species occurs and possibly can be explained by avoidance of competition with sympatric moud-nesting species.</jats:p>
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Comparative Aspects of Diet and Habitat in some New Caledonian LizardsBauer, Aaron M.; De Vaney, Kathleen D.
doi: 10.1163/156853887x00126pmid: N/A
AbstractNo comparative ecological studies have previously been conducted on the lizards of New Caledonia. This study examines two parameters of resource partitioning-diet and microhabitat, for eleven species of native lizards (Gekkonidae and Scincidae). Differences in diel activity patterns and coarse habitat differences tend to segregate geckos from skinks. Microhabitat and dietary differences were found among four sympatric species in a forest assemblage at Mt. Koyaboa, but retreat sites and some food resources were employed by all. Rock piles and crevices are important retreats for all the forest species studied and are a crude predictor of lizard abundance. Crickets and terrestrial isopods are the most important items in the diet of the predominant gecko Bavayia sauvagii. Though generally considered arboreal, this lizard is frequently active on the ground as well. Ants are an important food source of the forest skink Leiolopisma tricolor, whereas the ubiquitous ground skink Leiolopisma austrocaledonicum eats a wide variety of prey, with smaller individuals selectively taking smaller prey. Larger individuals consume feew large prey items but these may be of great energetic importance.
Comparative Aspects of Diet and Habitat in some New Caledonian LizardsBauer, Aaron M.; De Vaney, Kathleen D.
doi: 10.1163/156853887X00126pmid: N/A
<jats:sec><jats:title>Abstract</jats:title><jats:p>No comparative ecological studies have previously been conducted on the lizards of New Caledonia. This study examines two parameters of resource partitioning-diet and microhabitat, for eleven species of native lizards (Gekkonidae and Scincidae). Differences in diel activity patterns and coarse habitat differences tend to segregate geckos from skinks. Microhabitat and dietary differences were found among four sympatric species in a forest assemblage at Mt. Koyaboa, but retreat sites and some food resources were employed by all. Rock piles and crevices are important retreats for all the forest species studied and are a crude predictor of lizard abundance. Crickets and terrestrial isopods are the most important items in the diet of the predominant gecko Bavayia sauvagii. Though generally considered arboreal, this lizard is frequently active on the ground as well. Ants are an important food source of the forest skink Leiolopisma tricolor, whereas the ubiquitous ground skink Leiolopisma austrocaledonicum eats a wide variety of prey, with smaller individuals selectively taking smaller prey. Larger individuals consume feew large prey items but these may be of great energetic importance.</jats:p>
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