bluuebunny/crossref_metadata_2025_split huggingface dataset:
Communal breeding in the mara, Dolichotis patagonum
Authors: Taber A. B. , Macdonald D. W. 
Published: March 2009

Mara social organization involves a combination of monogamous territoriality and co‐operative, communal breeding that has not otherwise been described among mammals.Some pairs reared their young in communal warrens, and pup survival was greater in warrens with larger memberships.Pairs visited their young once daily, and females resisted, sometimes unsuccessfully, the attempts of interloping youngsters to nurse. Stolen nursing facilitated the survival of orphans.More adults were present at larger creches, and total vigilance was thus increased despite each pair spending less time sitting‐alert and less time at the warren. The proportion of the day for which at least one pair was vigilant at the warren increased to 90% with larger creche sizes.Pups were much more likely to emerge from the warren when adults were present, and in the absence of adults were more likely to be sitting‐alert close to the entrance.These observations are compatible with hypotheses explaining the mara's social system in terms of resource dispersion, anti‐predator behaviour and thermoregulation.
The hydrodynamic characteristics of six scallops of the Super Family Pectinacea, Class Bivalvia
Authors: Millward A. , Whyte M. A. 
Published: March 2009

Measurements have been made in a recirculating water channel of the lift and drag forces on the plaster casts of six scallops of the Super Family Pectinacea, Class Bivalvia, namely Chlamys varia, Amusium pleuronectes, Pecten irradians, Pecten senatorius, Pecten pallium and Pecten alba. The results have shown that the shape of the lift curve for the bi‐convex shells is similar to that of a comparable aerofoil shape, a discus, although with lower values. The piano‐convex shell had similar lift values but a lower stall angle.All the shells produced more induced drag than the discus and also had a higher form drag. Generally there was a correlation between the form drag coefficient and the thickness to chord ratio of the shell.It is suggested that Amusium pleuronectes would be the best adapted for swimming flight, because of its low drag characteristics, followed by Pecten senatorius and Pecten irradians. It is thought that, although Pecten alba was likely to be the worst swimmer of those tested, it was also likely to be best able to escape by its ability to develop lift.
Development of the eye and optic lobe of Octopus
Authors: Wentworth S. L. , Muntz W. R. A. 
Published: March 2009

The development of the lens, retina and optic lobes was followed in Octopus australis and O. pallidus, two species that produce benthic larvae and can readily be reared in the laboratory from egg to adult.The inner part of the lens starts to form at Naef's stage IX, and consists of a central core with overlying layers formed from processes of the lentigenic cells. Microvilli occur on the surface of the lens, and cilia and microvilli are visible in the retina, which at this point, however, is undifferentiated. The optic lobes have not started to form. The outer part of the lens starts to develop from stage XVI.Cellular differentiation of the retina, through cell nuclei crossing the basement membrane, starts at stage XV, with rhabdome development occurring from stage XVI onwards. The optic lobes are clearly formed at stage XII, but only start to differentiate and show layering from stage XVI.At hatching all adult structures are clearly visible, although considerable quantitative changes still occur before the final adult form is reached.The development of the visual system of Octopus is similar to that of several species of decapod previously reported.
The accessory nidamental glands of Loligo forbesi (Cephalopoda: Loliginidae): characterization of symbiotic bacteria and preliminary experiments to investigate factors controlling sexual maturation
Authors: Lum‐Kong A. , Hastings T. S. 
Published: March 2009

Accessory nidamental glands present in female myopsid and sepioid species have been previously reported to harbour bacteria, and descriptions of the bacterial isolates were limited to morphology or pigmentation. As yet, no attempt has been made to describe the biochemical characteristics nor to identify the isolates. The accessory nidamental glands undergo a colour change during maturation which is attributed to the symbiotic bacteria. Since the colour of the bacteria in the glands has been reported to reflect the maturity state of the host, they are potentially useful in investigations examining factors influencing sexual maturation in cephalopods.The present study describes the physical and biochemical characteristics of bacteria isolated from the accessory nidamental glands of Loligo forbesi Steenstrup and utilizes the isolates in preliminary experiments to investigate factors controlling sexual maturation.
Ergasilid copepods as parasites of perch Perca fluviatilis and roach Rutilus rutilus in Central Finland: seasonality, maturity and environmental influence
Authors: Tuuha Helena , Valtonen E. Tellervo , Taskinen J. 
Published: March 2009

A total of 1255 roach Rutilus rutilus (L.) and 866 perch Perca fluviatilis (L.) from four interconnected lakes in Central Finland differing in trophic status and pollution level were studied for parasitic ergasilid copepods between August 1985 and December 1988. In addition, 109 whitefish (Coregonus sp.) were studied from one of the lakes.Four ergasilid species were found: (the prevalence and intensity/fish, respectively, for the whole material are given in parentheses) Ergasilus briani (16·9%, 0·5), Neoergasilus japonicus (15·6%, 0·4) and Paraergasilus longidigitus (2·1%, 0·02) on the roach and Ergasilus sieboldi (9·9%, 0·1) and P. longidigitus (4·9%, 0·05) on the perch. Logit analysis was used to assess the significance of the year, the lake and the season for the prevalence of infection. Generally, the prevalence of E. briani on roach depended on the season only, with higher prevalences in summer. That of E. sieboldi on perch was mainly dependent on the lake, being most frequent in the oligotrophic lake. Both lake, year and season affected the prevalence of N. japonicus in roach. The more complicated system for N. japonicus was explained by the long duration of its free‐living stage, its loose attachment and different location on the host, being found on the fins whereas E. briani and E. sieboldi were on the gills.All species were found throughout the year, and age had no clear influence on infection. The occurrence of egg‐sacs and length distributions of the copepods suggest that there are two generations a year, e.g. an overwintering E. briani generation which produces offspring in June to attack the fish in July, and a second generation which attacks the fish from August onwards. Whitefish were not infected by these parasites, only one fish being found which carried a single individual of E. sieboldi.
The locomotory activity patterns of a functionally complete colony of Cryptomys hottentotus hottentotus (Rodentia: Bathyergidae)
Authors: Bennett N. C. 
Published: March 2009

The locomotory activity patterns of a colony of eight field‐captured mole‐rats housed in a transparent burrow system were monitored for a total of 240 hours. Movement along the burrow system was recorded for all hours of the 24‐hour chronological day for 10 days. Intermittent periods of activity were characteristic for all the mole‐rats in the colony. The lack of a distinct sleeping period reflects the asynchrony of each mole‐rat's activity cycle with that of other colony members. There are four major peaks of activity during the 24‐hour cycle and an absence of a well‐defined diurnal or nocturnal phase to the activity cycle.The nest area is a focal point in the burrow system with individuals spending between 36 and 81% of the day there. There is a positive correlation between the size of a group of sleeping mole‐rats in the nest and the frequency of occurrence.
Interspecific variation in daily energy expenditure during avian incubation
Authors: Tatner P. , Bryant D. M. 
Published: March 2009

Daily energy expenditure (DEE) of free‐living birds during the incubation and subsequent brood‐rearing stages was measured using the doubly‐labelled water technique for seven species of bird. These data are combined with published information to provide a data set of 17 species of bird covering the mass range 12–85 g.Allometric relationships between DEE and body mass for the two stages of breeding were constructed using three models (log‐transformation regression, geometric mean regression, and iterative non‐linear regression). The geometric mean regression model was rejected as inappropriate. The iterative non‐linear regression model provides the best predictions of DEE given the average body mass of a species, but is of less value for comparing data sets. The most commonly used model (log transformation regression) was thus favoured for comparative purposes as the predictions it generates do not significantly alter the conclusions that would be obtained with use of the iterative non‐linear regression models (Marquardt model) for the data sets in this work. Comparison between the average DEE for the two stages of breeding suggest higher DEE during the brood‐rearing period, although this was significant in only five species.The difference in body mass among species can account for more of the variation in average DEE during incubation (r2= 82·6%) than during brood‐rearing (r2= 67·3%1), indicating that other effects such as activity are probably more important determinants of energy expenditure during brood‐rearing.The residual variation in DEE during incubation, after the effect of body mass had been removed, was considered for groups of species occupying different ecological niches. It is shown that the level of activity and ambient temperature can explain much of the residual variation in DEE during incubation.The blue tit was used as an example to demonstrate the role of energy balance as a constraint on reproductive success during the incubation period.
Food of the serotine bat, Eptesicus serotinus—is faecal analysis a valid qualitative and quantitative technique?
Authors: Robinson M. F. , Stebbings R. E. 
Published: March 2009

The diet of Epfesicus serotinus was investigated by faecal analysis and the validity of this technique as a means of obtaining reliable quantitative results was assessed. Knowledge of what the bats eat will allow predictions of which habitats contribute most prey. Three male serotines were kept in captivity during the months of July and August 1991 and fed known quantities of identified insects. With captive E. serotinus the remains of prey appeared within 33 min of first bite and continued to appear for up to 32 h after consumption. Scales from two Noctua pronuba moths consumed were contained in 59 subsequent droppings. Similarly, fragments of three beetles, Geotrupes stercorarius, were contained in 28 subsequent faeces.Analysis of the faeces of free‐living bats revealed insects from seven orders. Coleoptera were found to be present in 96.1% of the droppings examined; the next most frequently found order was Lepidoptera, occurring in 14.7%. The beetles were mostly associated with hay meadows (Aphodius spp. and Melolontha spp.), or grazed pasture (Aphodius spp. and Geotrupes spp.). Quantitative determination of prey eaten is not possible owing to the large number of the droppings shown to contain the remains of marker insects and the long period over which they are produced.
Genital dimorphism in natural populations of the land snail Chondrina clienta and the influence of the environment on its expression
Authors: Baur B. , Chen X. , Baur A. 
Published: March 2009

Several species of simultaneously hermaphroditic land snails show a genital dimorphism: aphallic individuals differ from euphallic ones by a lack of male copulatory organs (penis plus genital retractor muscle). Aphallic individuals can self‐fertilize or outcross as females but not as males. Thus, the mating system of a population may be significantly influenced by the proportion of aphallic individuals.We present data on the frequency of aphally in 23 natural populations of the rock‐dwelling land snail Chondrina clienta on the Baltic island of Öland, Sweden. The populations varied greatly in percentage of aphallic individuals, ranging from 52.2 to 99.1%, (grand mean 77.7%)). This variation did not follow any geographical pattern.In a laboratory experiment, we examined whether food supply (high or low) and/or population density (high or low) experienced during ontogeny affected the expression of genital dimorphism. Snails derived from a population with 99.1% aphallic individuals and raised under different food and density conditions did not differ from the original population in frequency of aphally. By contrast, when snails from a population with 66.7% aphallic individuals were raised on a low food supply, more individuals became euphallic than expected under complete genetic determination. These results suggest that, in addition to a genetic component. the expression of the genital dimorphism can be influenced by environmental conditions.
The adaptive significance of brood size and time of breeding in the dipper Cinclus cinclus (Aves: Passeriformes) as seen from post‐fledging survival
Authors: Ormerod S. J. , Tyler Stephanie J. 
Published: March 2009

We assessed the post‐fledging survival of dippers Cinclus cinclus from 743 broods in relation to brood size, time of hatching and territory quality. We paid particular attention to assessing whether contrasting breeding performance along unproductive (i.e. acidic) and productive (i.e. circumneutral) rivers represented strategies which optimized the number of surviving young.For all brood sizes, post‐fledging survival varied significantly through the breeding season, with most survivors coming from attempts in the peak period of hatching. After correcting for these seasonal effects, the most common brood size overall, of four, was also the most productive as seen from post‐fledging survival; differences in the frequency of occurrence and survival between broods of four and five were marginal. Moreover, a change in the modal brood size from five to four occurred as the season progressed. consistent with a shift in brood productivity.Broods at acidic sites were significantly smaller than at circumneutral sites; while brood size four was the most productive at both types of site, brood size three was the second most productive at acidic sites, while brood size five was the second most productive at circumneutral sites. Dippers at acidic sites bred significantly later than at circumneutral sites, but post‐fledging survival declined most rapidly through the season at the former.These survival data provide evidence from both seasonal and spatial patterns that brood sizes in the dipper may be optimized in ways consistent with the enhancement of productivity. By contrast, delayed breeding at acidic sites contrasted with the patterns expected from optimization, instead reflecting resource scarcity.
Summer quiescent behaviour of the millipede Ommatoiulus moreleti (Julida: Julidae)
Authors: Bailey P. T. , Kovaliski J. 
Published: March 2009

The millipede Ommatoiulus moreleti (Lucas), (Julidae) originates in the south‐west Iberian Peninsula, and has successfully invaded parts of southern Australia with hot, dry summers. The species is inactive in the field during summer but is active in autumn, particularly following rains, and in spring. There is some activity in winter. In this paper, the temperature and humidity determinants of seasonal behaviour are analysed, in particular the conditions causing summer quiescence.Experiments using a millipede treadmill apparatus at different temperatures at 95% RH showed an almost linear response of locomotor activity with temperature between 3 and 21°C, but when the temperature was increased to 28°C, the millipedes became quiescent. Activity could he restored by reducing the temperature.When the millipedes were exposed to 45% RH there was comparatively little activity at any temperature. Field evidence indicates ii rapid breaking of quiescence with surface moistureThe success of O. moreleti in invading the surface‐litter habitat in South Australia can he explained by its ability to avoid desiccation; its adaptations include its quiescent behaviour during summer and its ability to moult from a winter (reproductive) to B summer (non‐reproductive) form.
The anatomy, chemical composition and maximum glycolytic capacity of adipose tissue in wild Svalbard reindeer (Rangifer tarandus platyrhynchus) in winter
Authors: Pond Caroline M. , Mattacks Christine A. , Colby R. H. , Tyler N. J. C. 
Published: March 2009

Adipose tissue was dissected completely from 21 female and two male Svalbard reindeer killed in the wild in December 1989. The gross mass, mean adipocyte volume, collagen content, the maximum activities of hexokinase and phosphofructokinase and the fatty acid composition of triacylglycerols were measured in samples of adipose tissue from at least 14 superficial, intraabdominal, cardiac and intermuscular depots homologous to those of other terrestrial mammals. The total adipocyte complement was calculated from the mass of each depot and its site‐specific adipocyte volume. Almost all the adipose depots found in other terrestrial mammals were present. Site‐specific differences in adipocyte volume were pronounced but, in contrast to other mammals, the glycolytic capacity of intermuscular adipose tissue was only slightly greater than that of other metabolically active depots, possibly because this subspecies does not naturally perform prolonged, strenuous exercise. All metabolically active depots except the cardiac adipose tissue enlarged with increasing fatness, but the superficial depots expanded more than any of the internal depots. Partitioning between anterior and posterior superficial depots was variable, with the posterior depots enlarging slightly more than the anterior depots. The adipose tissue in the hoof and around the eye was metabolically inert, but that of the bone marrow and the knee had low but detectable glycolytic capacity. The hoof and knee depots contained a high proportion of collagen, suggesting that they are load‐bearing structures.There was no statistically significant correlation between fatness and mean adipocyte volume and differences in fatness were due mainly to differences in adipocyte complement. Cell proliferation may be the principal mechanism of adipose tissue expansion in all superficial, intraabdominal and intermuscular depots studied. The total adipocyte complement was about twice that predicted from allometric equations relating adipocyte complement to body mass in other mammals and did not increase with age. There were no significant differences between lactating and non‐lactating females in any of the parameters measured. The mean volume of intra‐orbital adipocytes corresponded closely to that predicted from allometric equations. There were more unsaturated triacylglycerol fatty acids in the outer sides of the superficial depots and in other peripheral sites such as hoof, eye and distal marrow, indicating some biochemical adaptation to cooler peripheral tissues.
A histochemical comparison of fibre types in the M. pectoralis and M. supracoracoideus of the great skua Catharacta skua and the herring gull Larus argentatus with reference to kleptoparasitic capabilities
Authors: Caldow R. W. G. , Furness R. W. 
Published: March 2009

Skuas, which are closely related to gulls, frequently use a specialized feeding method (kleptoparasitism) by which they rob other seabirds of their food. This paper tests the idea that skuas have evolved as specialist kleptoparasites.The fibre type composition of the M. pectoralis, M. supracoracoideus and M. iliofibularis of a great skua Catharacta skua (Brünn.) and a herring gull Larus argentatus (Pontopp.) was determined by three enzyme histochemical methods commonly used for mammalian fibre classification; the reactions for alphaGPDH, NADH‐TR and mATPase activity.In both species slow fibres were present only in the M. iliofibularis, and fast twitch glycolytic fibres were not present in any of the muscles. The M. pectoralis and M. supracoracoideus of both species consisted entirely of the fast twitch oxidative‐glycolytic fibres.The overall metabolic enzyme activities of the muscles were assessed in terms of the proportions of fibres with high, intermediate and low metabolic enzyme activity. The overall levels of oxidative and glycolytic enzyme activity were significantly higher in the M. pectoralis than in the M. supracoracoideus and significantly higher in both of these than in the M. iliofibularis. This was true of both species.The oxidative and glycolytic activities of all three muscles of the great skua were significantly higher than those of the homologous muscles of the herring gull. This was particularly true of the M. pectoralis and M. supracoracoideus. It is suggested that this difference between great skuas and herring gulls enables the former to be more effective aerial kleptoparasites than the latter.
Variations of molar morphology in the Spalax ehrenbergi superspecies: adaptive and phylogenetic significance
Authors: Butler P. M. , Nevo E. , Beiles A. , Simson S. 
Published: March 2009

This study compares and contrasts variations of enamel fold pattern on the crowns of the molars of subterranean mole rats (Spalax) belonging to two superspecies, S. ehrenbergi and S. leucodon, and involving about 20 chromosomal species, distributed parapatrically and ranging on different soil types. The sample studied involved 397 skulls, subdivided as follows: 280 of S. ehrenbergi from Israel, representing the four chromosomal species 2n = 52, 54, 58 and 60; 59 of S. ehrenbergi from Egypt, Lebanon, Syria, Jordan and Turkey; 58 of S. leucodon from Turkey.In making the comparisons it was necessary to take into account the marked changes of molar pattern that take place as a result of wear.There is a reasonably good agreement between differences of molar pattern and genetic and immunological distances. The species in Israel and Egypt form a compact group, clearly differentiated from Turkish leucodon; ehrenbergi from Turkey and Syria are intermediate, in accordance with their geographical distribution.In Israel, differences associated with soil type are at about the same level as differences between species. Local populations show a higher level of diversity, and in a number of cases neighbouring populations differed significantly, sometimes over very short distances. Population differences within species are generally associated with differences of soil and vegetation, indicating the influence of natural selection. There are also differences across species boundaries, implying a phylogenetic (heritage) effect. The nature of the adaptive link between molar pattern and soil is unknown: possible factors are contamination of the food by soil, and toughness of the food which necessitates changes of enamel fold length to improve grinding efficiency.