bluuebunny/crossref_metadata_2025 huggingface dataset:
Observations on activity, display behavior, coloration and androgen levels in the keeled earless lizard, Holbrookia propinqua
Authors: Cooper William E. , Guillette Louis J.
Published: April 2008

We observed the distance moved, number of movements, and frequency of displays in ten minute intervals for two male color morphs, coral and yellow, and for brightly colored females, of Holbrookia propinqua. We also measured body sizes and, for males, plasma androgen concentrations. Distance moved, number of movements, and number of social displays were positively correlated in males. Females exhibited similar correlations, but the relationship between distance moved and number of displays was not significant. Males moved more often and greater distances than females. Females performed displays as frequently as did males, perhaps because we selected large, dominant females for observation. Distance moved, number of movements, and number of displays increased with body size in males. That these relationships did not hold in females may indicate a sex difference or reflect the small sample size and body size range of females. Plasma androgen concentrations increased with male body size, suggesting a possible androgenic mechanism of sexual selection for large size. Androgen level did not affect display frequency or distance moved. Distance moved increased with plasma androgen concentration, but when effects of body size were held constant, this relationship vanished. Coral and yellow males did not differ in androgen concentration, size, or in the observed behaviors.
Hybridization and low numbers in isolated populations of the natterjack, Bufo calamita, and the green toad, B. viridis, in southern Sweden: possible conservation problems
Authors: Schlyter Fredrik , Höglund Jacob , Strömberg Gunnar
Published: April 2008

Two isolated rock pool localities in southern Sweden with breeding green toads (Bufo viridis) and natterjacks (B. calamita) were studied, one on the mainland coast (Vik) and one on an island in the Baltic (Utklippan). Both localities are isolated by at least 30 km from other known populations of either species. A new character, dark throat patches present in B. calamita, aided in species separation on Utklippan. Body length was larger (9-41 % ) than reported from continental Europe. Individuals intermediate between the two species in size, morphologv and mating calls were found on Utklippan, suggesting the occurrence of viable hybrids. In Vik, neither of these characters nor electrophoretic data indicated hybridization. We suggest that the number of suitable breeding ponds may explain why the two species hybridize on Utklippan since only one sympatric breeding pond could be found on this site and a number of suitable ponds were found on Vik. Thus the species may be spatially more scparated at the Vik site making hybridization less likely to occur. However, few green toad males could be found on Utklippan making the sex ratio highly skewed. Accordingly, the low number of male green toad may explain why the species hybridize. Hybridization may be a potential threat to the persistence of endangered populations already in low numbers, if a large proportion of female gametes are wasted in hybrid matings. Thus this possibility is important when considering the conservation of endangered species.
Glandular epidermal structures in cordylid lizards
Authors: van Wyk J.H. , Mouton P. le F. N.
Published: April 2008

The epidermal glandular structures in lizards belonging to the family Cordylidae are described. In addition to the large tubulo-follicular holocrine glands in the femoral region, "glandular scales" in the femoral, pre-cloacal, dorsal body and anterior antebrachial regions resembling epidermal "generation" glands are for the first time described histologically. In contrast to generation glands described in other lizards, a sequential buildup of glandular generations occur in these structures. Based on histological features, two types of cordylid generation glands are recognized, depending on whether the sequential buildup of the glandular generations is above ("protruding" type) or below ("pit" type) the stratum germinativum profile of the normal epidermis.
The reproductive cycle of the newt Triturus italicus
Authors: Guarino Fabio M. , Caputo Vincenzo , Angelini Francesco
Published: April 2008

This paper describes the reproductive cycle in male and female newts Triturus italicus (Peracca, 1898) from a mountain population living in southern Italy. The male shows a well-defined seasonal testicular cycle: spermatogenesis almost stops from November to March, resuming in April-May; the maturative stage of spermatogenesis occurs in summer and spermiohistogenesis is completed by late October. Spermiation starts in late autumn and culminates in the next spring. The female shows a seasonal ovarian cycle. Vitellogenesis starts in September; ovulation and egg deposition occur between late January and early June. Thus potentially long reproductive activity is demonstrated in both males and females of T italicus. Testicular and ovarian weights seem to be reliable indices of the reproductive status of an animal. Annual variation in gonadal weight appears unrelated to annual variation in fat body weight in both sexes.
Progeny of water frog populations in central Poland
Authors: Berger Leszek , Berger W. Andrew
Published: April 2008

The authors discuss progenies of 18 watcr frog populations. Individuals with esculenta phenotype which arc hybridogenetic hybrids between Rana ridibunda and Rana lessonae are the most numerous frogs among the adults and progeny. Esculenta tadpoles began and finished their metamorphosis mostly as first, and in progeny with esculenta phenotype there were more females than males. In pure esculenta population most of progeny belonged to ridibunda phenotype and female sex. The froglets caught in August were larger on an average than those in October or after hibernation.
Size variation, growth and survivorship in nesting green iguanas (Iguana iguana) in Panama
Authors: Rand A. Stanley , Bock Brian C.
Published: April 2008

Over five years, 188 adult female green iguanas were captured one or more times, permanently marked, and measured at a nesting aggregation in Panama. Growth in these adult iguanas was very slow (averaging 6.8 mm/year) and appeared to be asymptotic, but there was substantial variability in the nesting female sizes observed (295 to 425 mm). This variation is biologically important because of the close relationship of female size to fecundity but little of this variation is explainable by differences in female ages (as estimated by skeletochronology) or in adult growth rates. Smaller females grew faster than larger ones but, controlling for size, younger iguanas did not grow faster than older ones. There is no evidence of alternative strategies with a trade-off between nesting sooner but smaller and nesting later but larger. Differences in adult sizes probably result from differences in juvenile growth rates, perhaps influenced by local differences in food quality and/or differences in the adult sizes at which growth trajectories asymptote. Energetic resources probably are not limiting for adult growth or reproduction. The high disappearance rate of iguanas from year to year (ca 60% per year) probably resulted mostly from mortality.
Adaptation of the reproductive cycle in Triturus alpestris apuanus to an unpredictable habitat
Authors: Andreone Franco , Dore Bruno
Published: April 2008

The annual reproductive cycle was studied in a Triturus alpestris apuanus population from northwestern Italy. Adult and larval newts were captured and measured monthly. By using histological techniques, the status and evolution of male gonads were examined. T. a. apuanus shows a post-nuptial gametogenesis, and testes reach their smallest size and weight in spring, when there are mainly mature sperm ampullae and yellow glandular tissue. Secondary sexual characters reach their maximum development during this period, decreasing during gametogenesis and increasing again in early autumn. Breeding activity begins at the same time, and is interrupted by the winter. Reproduction starts again in spring, lasting until summer. Eggs are laid at least twice a year, and the two larval cohorts live together. It is suggested that all these biological features are adaptations to unpredictable aquatic environments in a Mediterranean dry climate. These results suggest high levels of flexibility and variability in newt seasonal cycles.
In loco and systematic alteration in vitamin A content during tail regeneration in the gekkonid lizard, Hemidactylus,flaviviridis
Authors: Ramachandran A.V. , Valsamma E.P. , Shah R.V.
Published: April 2008

A quantitative evaluation was made of the levels of vitamin A in the liver, kidney and tail regenerate during tail regeneration in H. flaviviridis. Vitamin A in the liver increased on the first three days and decreased on the 5th day post-autotomy; a second increase was noted on the 7th day. Thereafter a subnormal level was noted on the 10th, 15th and 25th days. Vitamin A levels in the tail remained raised throughout regeneration except on the 7th and 60th days when the levels were in the normal (pre-autotomy) range. Kidney vitamin A content showed a steep increase on the 10th day while at other periods it remained in the normal range. The depletion in hepatic vitamin A content corresponded with high vitamin content in the regenerate, indicating the mobilization of this vitamin to the site of regeneration. The decreased level during dedifferentiation indicates greater utilisation of this vitamin. Supra normal levels of vitamin A in the regenerate during the blastemic and differentiation phases suggest an intimate association of this vitamin with the many events characteristic of these phases of regeneration.
Reproductive cycle of the parthenogenetic lizard Teius suquiensis
Authors: Martori R.A. , Aun L.
Published: April 2008

The reproductive cycle of the parthenogenetic lizard Teius suquiensis was studied. Females were reproductive after their second winter. The first eggs were laid in early November and oviductal eggs were present up to early January. Mean clutch size was 4.2 (range 2-8). Fat bodies were smallest during the reproductive season.
Variability and microevolutionary patterns in Triturus marmoratus from Portugal: age, size, longevity and individual growth
Authors: Caetano M.H. , Castanet J.
Published: April 2008

We conducted a comparative study of some biological parameters between different allopatric northern (high and low altitudes) and southern (low altitude) populations of Triturus marmoratus in Portugal. Individual age was determined by counting lines of arrested growth in histological sections of the humerus and phalanx. This study documents interpopulational differences in longevity, age of sexual maturity and growth of individuals. Individuals from high altitudes in the north reached older ages than those from low altitudes but both reached older ages than those from the south. Maturity was reached sooner among the southern newts for both sexes when compared to the northern populations. The southern newts also reached their sexual maturity at smaller mean sizes than the northern ones. We interpret these differences and suggest how genetical and epigenetical components can be both involved and account for the observed variability.
Sexual behaviour of Bosca's newt, Triturus boscai
Authors: Mouta Faria Manuel
Published: April 2008

The sexual behaviour of Bosca's newt, Triturus boscai is characterized by an extended phase of static display, during which tail fanning is the main display. This behaviour is similar to that of another species, T. italicus. During the static display phase males may also push the females' throat with the snout, and perform tail flicking movements. Unlike the other small-bodied Triturus species, T. boscai males receive very little or no indication on the part of the female signalling them to begin the spermatophore transfer phase, and do not perform retreat display. As in T. italicus, the tail-touch behaviour by the female of T. boscai appears to be less stereotyped than in the T vulgaris-helveticus-montandoni group. Spermatophore transfer success was highest at the beginning of the sexual encounters, the so-called early sequences. These sequences had little or no fanning behaviour before the spermatophore transfer. Luring behaviours are often performed, mainly during the spermatophore transfer phase.
Habitat choice of the salamander Chioglossa lusitanica: the effects of eucalypt plantations
Authors: Vences Miguel
Published: April 2008

Evidence is presented that golden-striped salamander Chioglossa lusitanica populations in eucalypt plantations may be subject to two influences. There is a low density of leaf litter invertebrates which are the preferred prey. Substrate choice experiments show that that the salamanders avoid eucalypt leaves as substrates for shelter. A long-term study of Chioglossa populations at two brooks in northern Portugal, however, showed that the numbers at one site did not change notably after plantation with eucalypts in comparison with the other, less altered, locality. Chioglossa is the most abundant amphibian species along water courses in the Spanish province of La Coruña, although eucalypts are planted along most of them.
Tree selection by the broad-headed skink, Eumeces laticeps: size, holes, and cover
Authors: Cooper William E.
Published: April 2008

Broad-headed skinks (Eumeces laticeps) are semiarboreallizards that are strongly associated with live oak trees (Quercus virginiana). Examination of the frequencies with which lizards occupied the largest of four nearest-neighbor trees and those having holes revealed a strong preference for large trees having holes. The presence of holes large enough for entry was a more important factor than tree size per se, as indicated by consistent occupation of smaller trees having holes when the largest of the four nearest neighbors lacked holes, although a significant preference for large size was demonstrated by the significantly greater than chance occupation of the largest of four nearest neighbor trees among those having holes. Large adults occupied significantly larger trees than did smaller adults, suggesting that larger individuals aggressively exclude smaller ones from preferred trees. Pairs consisting of an adult female and the male guarding her preferred trees surrounded by dense bushes, presumably because bushes limit detection and attack by predators and possibly because they harbor prey. Broad-headed skinks thus prefer large live oaks having holes and a fringe of dense cover.
Morphological variation and ecological distribution of co-occurring larval forms of Oreolalax (Anura: Pelobatidae)
Authors: Zhao Er-Mi , Inger Robert F. , Wu Guan-Fu , Shaffer H. Bradley
Published: April 2008

The amphibian fauna of Sichuan Province, China, is remarkable for the large number of species of pelobatid frogs, of which species of Oreolalax form a large portion. We have collected larvae of five species of Oreolalax on Mt. Emei, Sichuan, four of these five at a second locality 40 km from Mt. Emei, and larvae of two additional species at a locality 200 km S of Mt. Emei. These tadpoles are very similar to one another morphologically, a conclusion supported by multivariate analysis. We give diagnostic descriptions and a key for the identification of these seven larval forms. All tadpoles of Oreolalax have lotic habits, and the seven species in our study live in small to medium-sized streams (maximum width 8 m). These species show only moderate ecological segregation in terms of stream size and microhabitat type.
Survie et incubation des oeufs dans deux populations ovipares de Lacerta vivipara
Authors: Heulin Benoit , Osenegg Kirsten , Michel David
Published: April 2008

Lacerta vivipara est un lézard présentant à la fois des populations ovipares et vivipares. La survie et l'incubation des œufs ont été étudiées pendant quatre ans dans deux populations ovipares de cette espèce, à Louvie (370 m) et à Gabas (1100 m) dans les Pyrénées françaises. Dans la population de Louvie 25 à 56% des jeunes femelles de un an participent à la reproduction. Et la plupart des femelles adultes (âge>=2 ans) réalisent deux pontes par an. Dans la population de montagne de Gabas aucune femelle de un an ne participe à la reproduction, et moins de 20% des femelles adultes réalisent une deuxième ponte annuelle. Dans les conditions climatiques normales la période des premières pontes est comprise entre la deuxième et la dernière semaine de juin à Louvie, et entre la dernière semaine de juin et la mi-juillet à Gabas. La période de deuxième ponte a généralement lieu au cours de la deuxième quinzaine de juillet à Louvie, et au cours de la première quinzaine d'aout à Gabas. Le printemps frais de 1991 occasiona un retard de 2 semaines pour les périodes de pontes et d'éclosion de cette année. Un grand nombre de sites de pontes ont été découverts entre 1 et 3 cm de profondeur sous les mousses des tourbières étudiées. Dans les deux populations l'incubation des premières pontes dure environ 40 jours pour une température moyenne d'incubation de 18°C à 20°5. La durée moyenne d'incubation se réduit à moins de 30 jours les deuxièmes pontes de Louvie incubées à une température moyenne de 20°5 à 21°5. Les survies moyennes de œufs à Louvie et Gabas ont respectivement été de 0.49 et 0.84 pour les premières pontes et de 0.68 et 0.92 pour les seconde pontes. La prédation est la principale cause de mortalité des œufs et est particulièrement importante à Louvie. La courtillère Gryllotalpa gryllotalpa est très vraisemblablement responsable d'une grande partie (jusqu' à 44%) de la mortalité par prédation observée dans les pontes de Louvie. Les caractéristiques des populations ovipares ont été comparés à celles des populations vivipares précédemment étudiées. Ces données ne permettent pas de dégager des différences évidentes de dates de naissance et de taux de survie embryonnaire entre les deux modes de reproduction. En revanche elles confortent l'hypothèse théorique d'un accroissement de fécondité annuelle lié aux pontes multiples dans les populations ovipares de basse altitude.
Ecology of a Speleomantes ambrosii population inhabiting an artificial tunnel
Authors: Salvidio Sebastiano , Lattes Aldo , Tavano Maria , Melodia Federico , Pastorino Mauro Valerio
Published: April 2008

A Speleomantes ambrosii population living in an artificial tunnel in NW Italy was studied for two consecutive years. Activity on the walls varied cyclically in relation to seasonal temperatures and food abundance. The main food item was the trogloxenic dipteran Limonia nubeculosa, which accounted for more than 80% of the total ingested prey by volume. Juvenile cave salamanders had a broader trophic nich than adults. Oviposition and juvenile recruitment appeared to be seasonal. The spatial distribution inside the tunnel was related to microhabitat heterogeneity and particularly to the distance from the entrance. Juveniles were observed outside or close to the entrance more often than adults. Movement of adult salamanders were generally low and averaged 7 cm/day; some repeatedly recaptured individuals had a mean home range of 6 m2.
Changes in the components of phenotypic variance and covariance among traits during ontogeny in the sharp-snouted rock lizard (Lacerta oxycephala)
Authors: Aleksic I. , Tucic N.
Published: April 2008

We estimated changes in the components of phenotypic variance and covariance among seven metric traits over the first 90 days of growth in the sharp-snouted rock lizard (Lacerta oxycephala). The broad-sense heritability estimated from the data representing mostly size components of the seven morphometic traits over four age periods was about 90%. The average broad-sense heritability for the shape components of the same traits and age periods amounted to about 42%. By using bivariate and multivariate statistical methods, ontogenetic allometry coefficients have been estimated. The average heritability estimated for the bivariate allometric coefficients was about 69%. Genetic correlation structures were highly integrated within each age period and this integration increased from newborn lizards to lizards aged up to 90 days. For absolute measurements, phenotypic correlation structures were less integrated than genetic correlation structures, while for size-free measurements the opposite trend was observed.
Xenophidion, a new genus with two new species of snakes from Malaysia (Serpentes, Colubridae)
Authors: Günther Rainer , Manthey Ulrich
Published: April 2008

A new snake genus Xenophidion gen. nov., as well as two new species, X. acanthognathus spec. nov. and X. schaeferi spec. nov., are described on the basis of two specimens from Malaysia. Xenophidion is regarded as a distinct evolutionary lineage, presumably of the Colubridae, whose closest relatives remain to be identified.
Growth of the tropical sand lizard Liolaemus lutzae in southeastern Brazil
Authors: Rocha Carlos Frederico Duarte
Published: April 2008

The growth of males and females of the tropidurid lizard Liolaemus lutzae was studied in the seasonal tropical habitat of the restinga da Barra de Maricá, Rio de Janeiro State, southeastern Brazil. Growth rates of lizards decreased with size in both sexes; the size specific growth rates of females were significantly lower than those of males. Adult males were larger than adult females. The data indicate that despite maturing at a larger size, males grow faster than females and mature at similar ages. There was a significant relationship between amount of rainfall and lizard growth rate in both sexes.
Aspects of the reproductive biology of Physalaemus cuvieri (Anura: Leptodactylidae) in northeastern Brazil
Authors: Barreto Larissa , Andrade Gilda V.
Published: April 2008

Observations were made on the reproductive biology of Physalaemus cuvieri from open area habitat in São Luis, MA, Brazil, from August 1988 to August 1989. The reproductive tactics are compared to those of the same species in southeastern Brazil. Vocalization and reproductive activity were restricted the rainy season (January to June), with peaks of activity during late March and early April. Nocturnal calling activity turn was prolonged, with little variation in the number of individual calling during the night. The presence of communal foam nests suggests non-territorial behaviour in this species. However, males called from the same sites all night long. They showed differentiated vocalizations or antiphony, and aggressive physical interactions, which suggests that there may be some territorial behaviours in males. The remainder of the territorial behaviour is related to persistence of the invading male. Satellite behaviour, females mate choice, and a stereotyped behaviour (e.g. quick circular movement of both male and female) prior to amplexus, were also associated with territoriality.
Population structure of Emys orbicularis in the Bardello (Po Delta, Northern Italy)
Authors: Mazzotti Stefano
Published: April 2008

A population of Emys orbicularis in the Bardello (Po Delta, Northern Italy) was studied for 3 years using capture-mark-recapture methods, 23.6% of which were male, 57,5% female and 18.9% were juvenile specimens. The sex ratio of 127 specimens was 1:2. Certain morphometric variables such as the carapace length and shell height were examined in order to establish their sexual dimorphism. The population structure was defined by means of frequency distributions of carapace length. Using the Lincoln-Petersen and Jolly-Seber indices it was possible to estimate the population size as an average of 7.2 specimens per hectare.
Effects of testosterone administration and gonadectomy on nuptial pad morphology in overwintering male leopard frogs, Rana pipiens
Authors: Lynch Laura C. , Blackburn Daniel G.
Published: April 2008

Overwintering Rana pipiens were studied to clarify physiological control of the nuptial pad, a digital specialization of male frogs that is used in mating. Testosterone cypionate implants stimulated nuptial pad growth in both castrated and sham-operated males relative to placebo-treated controls. Androgen-induced changes in the nuptial pad simulated seasonal recrudescence, and included significant increases in thickness of both the epidermis and dermis, formation of keratinized epidermal papillae, hypertrophy of the gland epithelium, enlargement of the gland lumina, and cytoplasmic accumulation of secretory product. Castration did not influence the response to testosterone, nor did it markedly affect nuptial pad morphology, probably because the pads were in maximal regression. These findings, in conjunction with previous work, implicate testicular androgens in seasonal cyclicity of the nuptial pad.
The status of Caiman crocodilus crocodilus and Melanosuchus niger populations in the Amazonian regions of Brazil
Authors: Brazaitis Peter , Rebêlo George H. , Yamashita Carlos
Published: April 2008

Investigations were conducted throughout the Amazonian regions of Brazil to determine the distribution and status of Caiman c. crocodilus populations. Observations were made on the occurrence of Melanosuchus niger populations. Population data for river and lake/pond habitats are reported for 39 localities. Data suggest Caiman populations may be depleted in many regions. Melanosuchus populations are fragmented and have been extirpated from eight localities which had recent populations. Amazonian caiman populations are subject to increased human predation, environmental contamination with heavy metals, habitat modification, and lack of effective protection for wild populations.
Temperature regulation in the tortoise Testudo hermanni, studied with indwelling probes
Authors: Huot-Daubremont C. , Grenot C. , Bradshaw D.
Published: April 2008

Behavioural thermoregulation has been studied in the terrestrial tortoise Testudo hermanni in south-eastern France by implanting temperature-sensitive probes in free-ranging individuals. Three tortoises were monitored over a period of nine months (July to March); they maintained body temperatures close to their preferendum for periods of several hours each day. These results are of interest as doubt has been expressed in the literature on the thermoregulatory capacities of Testudo hermanni in the northernmost part of its range.
Feeding of amphibians during metamorphosis
Authors: Kuzmin Sergius L.
Published: April 2008

The feeding ecology of 28 amphibian species with complete life cycles has been studied from the last pre-metamorphic stages to metamorphosed juveniles. The widespread view that feeding ceases completely during metamorphosis is not confirmed. Generally, however, amphibian feeding rate decreases at metamorphosis. Foraging in Caudata either does not cease (Hynobiidae, rheophilous Salamandridae) or ceases only before the end of transformation, which takes less than one metamorphic stage. The cessation of foraging in Anura coincides with the transformation of the mouth and digestive tract at the beginning of the metamorphic climax. Foraging on small animals starts just after the change from a larval to a post-metamorphic mouth, i.e., before the end of metamorphosis.
The distribution and conservation status of the Danube crested newt, Triturus dobrogicus
Authors: Arntzen J.W. , Bugter R.J.F. , Cogalniceanu D. , Wallis G.P.
Published: April 2008

The range boundaries of the Danube crested newt (Triturus dobrogicus) are estimated from published data and new observations. The species range is restricted to the Pannonian and Dobrogean lowlands of central and eastern Europe. Its conservation status is determined as "vulnerable". The main cause of decline is habitat destruction through the conversion of wetlands, (semi-)natural land and pasture into arable fields.
Natural hybridization and introgression between Rana nigromaculata and Rana porosa porosa in central Japan
Authors: Sumida Masayuki , Ishihara Tatsuo
Published: April 2008

In order to elucidate the extent of natural hybridization and gene introgression between two Japanese pond frog species, Rana nigromaculata and Rana porosa porosa, 16 pond frogs from the Sengokuhara population in the Hakone district in central Japan were analyzed for morphological characters, allozymes, mtDNA and reproductive capacity. The results revealed that they consisted of pure Rana nigromaculata, F1 hybrids and a backcross hybrid.
Different temperature relations of two species of toads that coexist at the border of their geographical distributions
Authors: Katz U. , Gil Nira
Published: April 2008

Temperature relations of two species of toads (Bufo viridis and Bufo regularis) that overlap at the border of their geographical distributions were studied in the laboratory in temperatures between 25°C and 2°C. Bufo regularis, a tropical species, could not survive at low temperatures that eventually led to its death in 1-2 days. The two species did not differ in their cooling and heating rates. At temperatures below 8-10°C, Bufo viridis maintained a body temperature that was higher than ambient by 1-2°C, while body temperature of Bufo regularis equaled that of the environment. In Bufo regularis heart beats ceased at low temperatures (< 4°C), whereas in Bufo viridis at the same temperature, a rate of 6-9 beats/min was sustained. Our experiments suggest that Bufo viridis is endowed with particular capacities that allow it to remain active at low temperatures, while in Bufo regularis, a temperature-sensitive central mechanism seems to be damaged at low temperature. The ability of Bufo viridis to endure low temperatures and to remain active in this condition is specific to the species, and is not related directly to the immediate ecological situation of the animal.
Flow cytometry in biodiversity surveys: methods, utility, and constraints
Authors: Murphy Robert W. , Lowcock Leslie A. , Smith Cheryl , Darevsky Ilya S. , Orlov Nikolai , MacCulloch Ross D. , Upton Darlene E.
Published: April 2008

Flow cytometry of blood is a powerful tool for rapidly sorting individual specimens on the basis of cellular DNA content. During biodiversity surveys, the method enabled the early identification of both cryptic sympatric and allopatric species of Vietnamese ranid frogs. This method may be extremely valuable in sorting individuals from other taxa and geographic regions, especially when cellular DNA content is known to vary among closely related taxa, and in tropical situations where crypsis is a relatively common phenomenon. Protocols for preparation of freezing solution, field procedures, preparation of reference standards, and flow cytometric analysis are provided. The best method for field preservation of blood is freezing in liquid nitrogen; field fixation of blood in ethanol was less efficient and resulted in drastically increased coefficients of variation. Once samples have been transferred to freezer storage, they should not be returned to a lower storage temperature in liquid nitrogen.
Independent evolution of squamate olfaction and vomerolfaction and correlated evolution of vomerolfaction and lingual structure
Authors: Cooper William E.
Published: April 2008

The comparative abundances of chemoreceptor cells for olfaction and vomerolfaction, the sense mediated by the vomeronasal organs, were studied in numerous squamate families, with emphasis on lizards, and compared with abundance of lingual taste buds and aspects of lingual structure likely to be related to chemosensory sampling for vomerolfaction. Abundances of vomerolfactory receptors vary greatly among, but little within squamate families. Using Felsenstein's method of independent contrasts, the abundance of vomeronasal receptors is significantly correlated with size of lingual tines, degree of lingual elongation, and condition of sampling surfaces (pallets) on the ventral side of the tongue. This indicates that correlated evolution has occurred. An intimate relationship exists between the chemosensory organ and its primary sampling device, highlighting a lingual-vomeronasal complex that functions to sample and analyze chemical stimuli from external environmental surfaces. Attributes enhancing lingual facility for chemical sampling are forking, which permits scent-trailing by tropotaxis, and possibly elongation, which may permit greater extension beyond the mouth or enhance maneuverability. Ventral lingual pallets, surfaces that directly contact substrates during sampling, are large in forms having low abundances of vomerolfactory receptors, but are reduced and are eventually lost with progressive increases in vomerolfactory receptor abundance. Pallet condition is negatively correlated with tine size and lingual elongation. Large tines appear to take over the sampling function in forms lacking pallets. Lingual taste bud abundance is negatively correlated with vomerolfactory receptor abundance, forking, elongation, and positively with pallet condition. The negative correlation between the abundance of vomerolfactory receptors and lingual taste buds may be attributable to physical incompatibility between taste buds and specialized modifications of the foretongue for vomerolfactory sampling or to loss of opportunity for lingual taste buds to function in vomerolfactory specialists that lack lingual functions such as prey prehension, manipulation, and transport and in which the tongues are ensheathed while in the mouth. The abundances of olfactory and vomeronasal chemoreceptor cells are uncorrelated using Felsenstein's method. Thus, olfaction appears to have evolved independently of vomerolfaction.
A new species of Eleutherodactylus (Anura: Leptodactylidae) from the Andean slopes of Bolivia
Authors: Reichle Steffen , Köhler Jörn
Published: April 2008

A new species of frog of the genus Eleutherodactylus is described from Valle del Zongo, Departamento La Paz, Bolivia. This species of the E. discoidalis group is most similar to E. cruralis, but differs in dorsal tuberculation, color, and head proportions.
Reproductive ecology of Bombina variegata: aspects of life history
Authors: Barandun Jonas , Reyer Heinz-Ulrich , Anholt Bradley
Published: April 2008

Individual reproductive behaviour and survival of Bombina variegata was studied in a dynamic habitat with a variety of rain-filled ponds from 1990 to 1992. Most animals reached sexual maturity at the age of two years. Annual adult survival was at least 62%. Individual females, on average, laid between 40 and 70 eggs per "clutch". While about 12% of the breeding females spawned a second time within the season, a similar proportion did not seem to spawn every possible year, probably depending on climatic conditions. The results are consistent with ultimate predictions from life history theory, but the proximate mechanisms of ovulation and spawning in response to environmental conditions remain to be investigated.
Allometry and morphological integration in the skull of Tupinambis merianae (Lacertilia: Teiidae)
Authors: Monteiro Leandro R. , Abe Augusto S.
Published: April 2008

The morphogenetic processes acting in the skull of the lizard Tupinambis merianae were investigated by geometric morphometric techniques. The observed ontogenetic shape change involved a widening of the anterior extremity, stretching and narrowing of the midface, narrowing of the braincase, orbital reduction and elongation of the temporal region (origin of jaw adductor muscles). This change occurred mostly in a localized way in certain cranial regions. The major components identified were: rostrum, midface, dermal elements of braincase (functionally influenced) and endochondral elements of braincase (embryologically influenced). The growth patterns lead to an increased robustness of the skull (particularly the anterior extremity) and a reduction of cranial kinesis. These changes, together with the ontogenetic variation in dentition aid in the ontogenetic variation observed in the diet of these animals, which shift from carnivory to omnivory.
The first record of snakes on the Canary Islands: a vertebra from the Upper Miocene of Lanzarote
Authors: Barahona Fabiola , Rage Jean-Claude , García-Talavera Francisco
Published: April 2008

The Upper Miocene fossil site of Orzola in Lanzarote (Canary Islands) has produced an isolated snake vertebra attributable to the Boidae. This is the first report of a snake, either fossil or living, from these islands, which provides further evidence of a greater faunal diversity in the past.
Migration patterns and diurnal use of shelter in a ranid frog of a West African savannah: a telemetric study
Authors: Spieler Marko , Linsenmair Karl Eduard
Published: April 2008

A telemetric study on Hoplobatrachus occipitalis (Anura: Ranidae) was conducted in the Comoé National Park (Ivory Coast, West Africa) from 1993 to 1995 during the beginning of the rainy seasons. Radio transmitters were implanted into 46 frogs. The locations of individual animals were tracked for 2 to 71 days, at least once per day and once per night. By day, the frogs were found in diurnal shelters that offered favorable temperature and humidity conditions as well as protection against predators. At night, with the beginning of the rainy season, both males and females occupied about equally large home ranges of on average 142 m2 (range: 23-3744 m2) in a partially dried-up river bed. Individuals with home ranges on rocky stretches along the river weighed significantly less (35 ± 9 g) and occupied significantly larger home ranges (median: 944 m2) than did individuals found in places along the river having dense and shady vegetation (median of home range: 45 m2, body weight: 66 ± 21 g). Frogs migrated when precipitation was above 15 mm per day (movement >30 m per animal and day). Movement over longer distance (>600 m per animal and day) took place only once a year, when the first heavy rainfall of the season filled the dried-up ponds in the savannah. On these longer migrations, nearly all radio-tracked frogs moved from the river to newly emerged ponds in the savannah, covering linear distances of up to 1.4 km in a single night. The frogs then stayed in the savannah and most of them repeatedly sought new breeding sites during the rainy season. Thus, the total space covered by the frogs, termed "activity area", amounted to up to 2 km2, for both sexes, during the observation period.
Activity patterns and microhabitat selection of Mallorcan midwife toad (Alytes muletensis) tadpoles in natural torrent pools
Authors: Schley Laurent , Griffiths Richard A. , Roman Alvaro
Published: April 2008

Tadpoles of the Mallorcan midwife toad (Alytes muletensis) displayed a clear diel pattern of activity and microhabitat selection in torrent pools in Mallorca. Tadpoles spent much of the day foraging in a non-aggregated fashion in warm shallow areas, and activity peaked at 1700-1900 hr. In mid-afternoon, however, when much of the water surface was in direct sunlight, tadpoles moved away from the shallows and formed aggregations under rock overhangs at the sides of the pool. Both activity and tadpole density in the shallows dropped dramatically after dark, when there was a movement of the population back into deeper water or hiding places.
The Sexual Behaviour of Two Sibling Drosophila Species
Authors: Manning Aubrey
Published: April 2008

1. The courtship behaviour of Drosophila melanogaster and D. simulans has been studied. Melanogaster is a generally more active species than simulans and its courtship is more vigorous. 2. The sexual behaviour of both types of male can be readily classified into the same basic elements, orientation, wing display, licking and attempted copulation. 3. Simulans males have longer lag periods before courtship, longer bouts of simple orientation, fewer changes of element when courting and their chief wing display is 'scissoring'. Melanogaster's chief wing display is 'vibration'. 4. Experiments in which the sexual stimulus situation was changed show that with lower stimulation melanogaster males show an increased proportion of scissoring, while with increased stimulation simulans males show more vibration. Additional reasons are given for considering scissoring to represent a lower level of sexual excitation than vibration. 5. The differences between the males can be most simply ascribed to simulans having a slower rise of sexual excitation during courtship than melanogaster, not to any changes in the basic organization of their behaviour. This slowed rise may be related to higher thresholds of response in simulans. 6. The females of simulans are more responsive to visual aspects of their males' courtship, and less responsive to those stimuli perceived by their antennae, than are melanogaster females. 7. It is argued that these changes in courtship behaviour probably resulted from selection acting upon a common ancestral population so as to favour high activity in some environments and low activity in others. These changes will be most readily produced by mutations affecting reaction thresholds and the changes to courtship pattern will follow. Selection will then favour females responsive to the most easily available stimuli from the males' courtship. 8. It is suggested that similar situations occur in other sibling Drosophila species and that as a first step in behavioural divergence, mutations affecting thresholds will be particularly important.
Suckling Behaviour in Kittens
Authors: Ewer R.F.
Published: April 2008

The feeding behaviour of two litters of four kittens each has been studied. Düring the first few days of life each kitten gradually establishes ownership of one teat, and then rarely feeds from any teat but its own. One kitten was exceptional in establishing ownership of two teats. Teat constancy is well maintained until the kittens become active enough to leave the nest and feed independently of the mother at the age of about 32 days. From this age until the end of lactation, although teat constancy is less rigidly maintained, it doet not vanish completely. The factors which bring about this reduction in teat constancy are discussed. Some incidental observations on the behaviour of the females towards the kittens of the foreign litter are included. The clues which a kitten may utilise in recognising its own teat and the biological significance of teat constancy are briefly considered.
Further Observations On Suckling Behaviour in Kittens, Together With Some General Considerations of the Interrelations of Innate and Acquired Responses
Authors: Ewer R.F.
Published: April 2008

The feeding behaviour of kittens includes an appetitive searching component and a sucking response to a teat once this is found. The searching pattern is shown immediately after birth but the kittens usually do not feed until 1 or 2 hours later. This may be either because the sucking response has not yet matured or because the teats do not provide the correct releaser until milk secretion is well established. As the kittens become older the searching pattern undergoes modification which has the characteristics of trial-and-error learning. The sucking response, after a few days, becomes restricted to one teat but later as the kittens begin to become independent of the mother there is some relaxation in this restriction and teat constancy declines. The birth of two litters within 24 hours of each other allowed tests to be made of the response of the kittens to a foreign mother. At first there is no response to a foster mother's teats, including the one corresponding in position to the kitten's "own" teat. At about the same age as the kitten's teat constancy on its own mother starts to decline it begins to accept a teat on the foster mother. This indicates that the kitten's recognition of its own teat depends on a chemical factor, not on anatomical position. The adaptive significance of this behaviour is discussed. It is suggested that the reason for the difference between endogenous patterns and those synthesised in relation to individual experience is to be sought in the adaptive significance of the end results. Where selection favours a species-specific pattern an endogenous ontogeny necessarily follows. In the course of evolution the basis of certain types of behaviour has shifted from endogenous to experience-synthesised or vice versa. This implies that the differences between the two may not be very fundamental and it is suggested that any attempt to "compartmentalise" the study of behaviour is likely to be unprofitable. It may be heuristically more valuable at the present time to turn our attention to the similarities, rather than the differences, between endogenous and experience-synthesised patterns.
The Motivational Organisation Controlling the Mobbing Calls of the Blackbird (Turd Us Merula). Ii. the Quantitative Analysis of Changes in the Motivation of Calling
Authors: Andrew R.J.
Published: April 2008

1. At least two variables must be used for the adequate analysis of the changes observed in calling. The first has been here termed Action Potential (A). When the value of A at calling is above a certain threshold 'tix' is given instead of 'duck'. A is caused to rise both by activity of the neural system controlling flight and by the sight of a frightening object. It is reduced by calling, probably at or just after each call. 2. A second variable, the General Threshold for calling (T), must also be employed to explain the data obtained. When A is below T no calls can occur. T is increased by calling (probably at each call, since there is some evidence that it decays between calls). It therefore rises progressively during bouts. As a result the interval between the last two calls of a bout is an unusually long one, and the change to 'tix' is irreversible within a bout. Between bouts T decays, so that the longer the pause between bouts the shorter the intervals between calls at the beginning of the next bout, and the less likely is it that the first call will be 'tix'. 3. The higher the value of T at the beginning of a bout the longer the intervals between calls and the more likely is the change to 'tix', since A has to rise to equal T before calling can occur. 4. T tends to fall a take-off and rise at landing. 5. High intensity calling may take two forms which are caused by differences in the rate of accumulation of T. When T accumulates slowly the intervals between calls readily decrease until the physical limit is reached, and a scream results, in the course of which the change to a 'tix' type of calling occurs. A scream is initiated only after the activity of flight has continued for more than a minimum period of time, which is longer the lower the intensity of mobbing. When T accumulates readily, long bouts result, which are entirely composed of 'tix' calls, given at unusually long intervals.
A Quantitative Study of the Behaviour of the Male Mormoniella Vitripennis (Walker) (Hymenoptera, Pteromalidae) Towards Two Constant Stimulus-Situations
Authors: Barrass Robert
Published: April 2008

1. The method of dual quantification was used to study the effect of courtship of both receptive and non-receptive females on the subsequent behaviour of the male Mormoniella vitripennis. 2. The male's responsiveness to successive non-receptive females waned when the time between presentations was short. The extent of this waning was less with longer time intervals. 3. When many females were presented to a male one after another the male courted almost all of them if they were receptive females but only a few if they were non-receptive females. 4. A single courtship of either a receptive or a non-receptive female had a similar effect on the male's subsequent behaviour and recovery occurred in a similar way. 5. Courtship of 20 non-receptive females reduced the male's response to further females more than did courtship of 20 receptive females. 6. The significance of these observations is discussed with reference to the use of dummy animals and to the recent ethological concepts of reaction specific energy, motivational impulses, specific action potentiality and consummatory act. 7. An endogenous central nervous influence on the male's readiness to respond is postulated. Courtship has a short-term response-specific effect (receptive or non-receptive females) and an inhibitory stimulus-specific effect (non-receptive females). With receptive females the inhibitory effect is absent and/or mating has an excitatory effect. The stimuli provided by a receptive female must direct nervous activity rather than release a limited amount of stored energy.