bluuebunny/crossref_metadata_2025_split huggingface dataset:
Allometry of gill dimensions in some British and American decapod crustacea
Authors: HUGHES G. M. 
Published: August 2009

The gill areas and their component measurements of 16 species of North American crab and seven species of British decapod crustaceans have been analysed in relation to body mass using the method of logarithmic transformation.A wide range of relationships was found, each of which is typical for a given species. The slope, b, of the log/log regression lines varied from 0·5 to 1·0, the lower values being most commonly found in the Macrura. For the North American species the average slope is about 0·8 whereas for British brachyurans the relationship was close to linear (b=0·97).The analysis shows that the increase in gill surface body size is mainly due to the increasing area for individual platelets or gill lamellae.Comparison of weight‐specific gill areas for animals of the same body weight suggests that the most active species have larger gill areas. For some of these species the values (900mm2/g) approximate to those of active fish.As plots for interspecific relationships derived from average values for many individual species have slopes which are not typical for any of the component species, it is concluded that caution must be exercized when interpreting such interspecific plots in Allometric studies.
Ultrastructural distribution of morphology of the mammary gland with observations on the size fat droplets in milk of the Weddell seal Leptonychotes weddelli (Pinnipedia)
Authors: Tedman R. A. 
Published: August 2009

Ultrastructural observations were made of the non‐lactating and lactating mammary gland of the Weddell seal, and measurements of several cell components were compared with those in other species to determine whether there are any morphological modifications within the gland to explain the unusual milk composition and very rapid growth of sucking young in this species.The mammary parenchyma in non‐lactating and lactating Weddell seals is almost identical morphologically to that found in other mammals. Although the relative volumes of most organelles are similar to those in other eutherians, the relative volume of rough endoplasmic reticulum (RER) is reduced in the Weddell seal. In addition, the absolute and relative volumes of Golgi vacuoles are smaller in the Weddell seal, probably associated with the low lactose and water content of the milk. The synthesis and secretion of milkspecific proteins and fat droplets by mammary secretory cells in the Weddell seal appear to be identical to other eutherians. Relatively small numbers of fat droplets less than 1 μm diameter are present in epithelial cells, alveolar lumina and milk samples, and there is a far greater contribution by large fat droplets to the total fat volume of Weddell seal milk than milk from other mammals.
Energetics, body size, and the limits to endothermy
Authors: MCNAB BRIAN K. 
Published: August 2009

The scaling rate of metabolism with respect to body mass is analysed. Scaling of heat production implies that scaling also exists between temperature regulation and body mass. Most vertebrates follow a Kleiber relation down to a “critical mass, below which the scaling of metabolism must be changed to ensure the maintenance of endothermy. Such an adjustment is found interspecifically in birds and mammals, and is found intraspecifically in mammals during post‐natal growth. If the Kleiber scaling relation is maintained below the critical mass, mammals and birds shiR from endothermic temperature regulation (above critical mass) to endothermy with obligatory torpor (below critical mass). If the Kleiber relation is followed to masses far below the critical mass, ectothermy results. Critical mass varies inversely with the level of energy expenditure, which therefore accounts for the fact that most mammals and birds are endotherms and most reptiles and fish are ectotherms. The same relationship permits the facultative endothermy found in some insects and plants.The scaling relations existing among rate of metabolism, endothermy, and body mass can be written as a modification of the Kleiber relation. This analysis suggests that any organism, irrespective of phylogenetic position, can be endothermic at any body size, if its rate of metabolism is high enough, or can be endothermic with any rate of metabolism, if it is large enough. Consequently, it is difficult to distinguish minimal endothermy from inertial homoiothermy in animals having a large mass. The boundary conditions for effective endothermy are similar to the relationship described between metabolism and mass in the evolution of endothermy through a decrease in mass in the phylogeny of mammals. Even though endothermy may evolve with an increase in mass, its perfection may always require an evolutionary decrease in mass.
Studies on an Indian polydesmoid millipede Streptogonopus phipsoni Life cycle and swarming behaviour of the larvae
Authors: Bellairs Vivien , Bellairs Ruth , Goel S. 
Published: August 2009

The adults of Streptogonopus phipsoni (Pocock), an Indian polydesmoid millipede, emerge from the soil at the onset of the monsoon and mate. Eggs are laid in the soil and the adults die. The larvae leave the soil at stadium III and, apart from moulting periods, remain on the surface until the end of the monsoon. The larvae are aggregated in swarms, usually consisting of several hundred individuals. They are active on open ground, including metalled roads, during daylight, but usually spend the night in an inactive state under cover of stones or vegetation. If a swarm is disturbed, the individuals scatter but later reaggregate.Laboratory experiments show that the larvae are sensitive to light even though they lack eyes, and if given a choice spend more time in the light than the dark. Just before and after moulting however they spend more time in the dark than in the light.Experiments were carried out on the reactions of the larvae to aquatic suspensions of benzaldeyde, since this substance is related to components of the exudate of the repugnatorial glands; strong concentrations (10‐1) repelled the larvae, whilst weak concentrations (10‐6) attracted them. It is suggested that swarms may be dispersed or reaggregated by the effects of variations in concentration of components of the exudates. The benefits to the larvae which may result from swarming are discussed.
A taxonomic reappraisal of the Daphnia hyalina complex (Crustacea: Cladocera): an experimental and ecological approach
Authors: Christie P. 
Published: August 2009

The paper is a taxonomic study of the limnetic Daphnia populations of the English Lake District, the populations upon which the most popular taxonomic scheme is based (Johnson, 1952).Johnson treats these populations as three varieties of the species D. hyalina, namely D. hyalina s. str., D.h. var. galeata and D.h. var. lacustris.Careful examination of the populations of Esthwaite reveals that what has previously been regarded as a population of a single variety of D. hyalina. includes three distinct forms. Experimental work confirms that these are genetically distinct. One of these forms corresponds to D. hyalina var. galeata, whilst the other two are designated the “toothed” and “round‐headed” forms.The first part of the paper is concerned with the taxonomic status of var. galeata. Brooks (1957) and some later workers treat this as a separate species (D. galeata) on morphological grounds. This is fully supported by the present work. Differences between var. galeata and co‐existing forms in incidence of sexual reproduction, in vertical distribution and in seasonal abundance and average brood‐size provide further support for the separation of D. galeata.The second part of the paper is concerned with D. hyalina s.str. which, on the basis of morphology, ecology and reproductive behaviour, is shown to be at least as distinct from other members of the complex as is D. galeata. It is argued that other forms should therefore to be removed from D. hyalina. The taxonomic status and affinities of the remaining “toothed” and “round‐headed” forms are discussed.
Breeding biology of the Light‐mantled sooty albatross (Phoebetria palpebrata) at South Georgia
Authors: Thomas G. , Croxall J. P. , Prince P. A. 
Published: August 2009

Aspects of the breeding biology of the Light‐mantled sooty albatross Phoebetria palpebrata were studied at South Georgia. Its breeding distribution there is summarized and an annual breeding population of c. 5000 breeding pairs estiamted. Laying, hatching and fledgine dates are given, together with egg measurements and data on the duration of incubation and brooding shift. Chick growth in weight and wing length from hatching to fledging was followed in detail.Breeding season adaptations of P. palpebrata are compared with those of the other three albatrosses at South Georgia. The slow chick growth of P. palpebrata results in a nestling period even longer than those of the two larger mollymawks and is attributable mainly to the lower frequency of feeding resulting from the highly pelagic existence of adult P. palpebrata.Comparisons are made with other breeding populations and especially with that on Marion Island. This is basically very similar and differences in chick growth patters are suggested to relate to differences in diet and particulartly to the frequency with which chicks receive food.
The nutritional value of invertebrates with emphasis on ants and termites as food for mammals
Authors: Redford Kent H. , Dorea Jose G. 
Published: August 2009

Water, ash, total nitrogen and fat contents were determined for the worker and soldier castes of nine species of central Brazilian termites. These values were then compared with those from other species of termites, ants and 22 other species of terrestrial invertebrates. In comparison with most other invertebrates, termite workers and soldiers tend to be high in ash, low in fat and about equal in water and nitrogen. In contrast, alate ants and termites and most larval or pupal insects have much higher percentages of fat. It is pointed out that most protein and total energy values for arthropods are of limited use because the assays used incorporate the nitrogen present in the indigestible chitin exoskeleton.It is concluded that most invertebrate‐eating mammals choose prey based on availability and other aspects of prey biology and not on gross nutritional factors. The problems associated with eating ants and termites are discussed and include low nutritional value of prey, small prey size and forms of defense relying on the sociality of the prey.
Fatigue fracture of mother‐of‐pearl and its significance for predatory techniques
Authors: Currey J. D. , Brear K. 
Published: August 2009

Specimens of nacre from the pearl oyster Pinctada margaritifera were loaded in bending to various fractions of the load needed to cause fracture. For a small number of cycles, less than about 1000, no changes in compliance or strength were found if the load was less than about 60% of the load necessary to cause failure. Above this fraction the compliance increased, the strength usually decreased but occasionally increased.We conclude that, because the loading of a shell by a predator is likely to be far less controlled than loading by a machine, causing a shell to break by fatigue fracture is unlikely to be a tactic employed by a predator, though it may happen fortuitously.
Impact of winter nutrition on reproduction in captive Mountain hares (Lepus timidus) (Mammalia: Lagomorpha)
Authors: Pehrson2 A. , Lindlöf B. 
Published: August 2009

SummaryDuring winter‐time, two groups of captive female Mountain hares were fed food of high and normal quality respectively, in order to study the impact of winter nutrition on reproduction the following summer.On average, the animals fed on high quality food increased their weight 19.2% from December to April, while the corresponding figure for the other group was 7.1%. Neither the size of the first, nor the second litter of the year differed between the two feeding regimes.In the first litter, the leverets from the females fed high quality food had significantly higher birth weights (149.5±24.4 g) than the leverets from the normally fed females (108.5±25.6 g). The second litter of the year showed no such differences.Gestation time was similar for the two groups and showed small fluctuations around a mean value of 51 days. Juvenile growth rate amounted to an average of slightly below 30 g per day during the first 2–3 months.We are most grateful to Dr Olav Hjeljord and Dr Jonathan Reynolds for valuable criticism of the manuscript. Dr Reynolds also kindly checked the language for us.
The gobiid fishes of temperate Macaronesia (eastern Atlantic)
Authors: Miller P.J. 
Published: August 2009

Eight species of gobiid fishes have been recorded from the islands comprising temperate Macaronesia (Azores, Canaries, Madeira and Salvages), These are (iohius niger L., G. auralus Risso, G. gasteveni Miller, G. paganellus L., Lesueurigobius heterojaseiatus Maul, Mauligobius maderensis (Valenciennes) and Thorogobius ephinppiatus (Lowe), with L. suerii (Risso) remaining unconfirmed. The identification, records, characteristics, and habitat of these species in the Macaronesian islands are considered. The genus Mauligobius Miller is fully defined and the type‐species, Gobius maderensis Valenciennes, endemic to Madeira and the Canaries, described in detail. The transfer of the little‐known West African Gobius nigri Günther to Mauligobius is suggested. Phylogenetic discussion of Mauligobius, in relation to Atlantic‐Mediterranean and Ponto‐Caspian forms, indicates its position as the sister group to Gobius. The modern Macaronesian gobiid fauna seems to be derived from the warm‐temperate eastern Atlantic‐Mediterranean marine province. The presumed absence of M. maderensis from the Azores, and the pattern of meristic variation in Gobius paganellus, support the view that the continental rise islands do not have a direct faunal interrelationship with the Azores, and that common possession of Atlantic‐Mediterranean species reflects supply from the same outside source rather than by interchange. The likelihood of finding more gobiid species in Macaronesia is noted. A model of speciation in Mauligobius. in relation to hydrographic events, is suggested.Appendix 1 summarizes features of marking and head lateral‐line system useful for distinguishing juvenile G. paganellus and M. maderensis. Appendix 11 provides a redescription of the holotype of Gobius nigri. and a discussion of geographical occurrence, habitat, and affinities for this species.
The biology and functional morphology of Clavagella australis (Bivalvia: Anomalodesmata)
Authors: Morton Brian 
Published: August 2009

The biology and functional morphology of the unusual boring anomalodesmatan bivalve Clavagella (Dacosta) australis (Clavagellacea) is described. The animal occupies a borehole in calcareous (including coral) rocks to which it cements itself by the left shell valve. Radial mantle glands developed in the middle folds of the siphonal tip produce the glue but also stick sand grains to the periostracum to camouflage the siphons. The right valve is free. The shell is somewhat inequilateral in form, the adductors large and slightly heteromyarian. The pallial retractor muscles are also large so that the ventral mantle is very thick. Because mantle fusion involves inner, middle and inner surfaces of the outer folds (type C), the periostracum is continuous so that shell and mantle are almost completely, except for the siphonal orifices and the pedal gape, enclosed in periostracum. The simple sunken primary ligament comprising inner ligament layer only and located between chondrophores is flanked anteriorly and posteriorly by fused periostracum, assisting, in the absence of teeth, in hinge alignment.Boring is probably a chemical process, a secretion from the inner surface of the anterior mantle being discharged onto the burrow wall from the pedal gape. The calcium carbonate eroded in this way is possibly used to partially line the burrow. The distal siphonal tube, however, is secreted from siphonal glands discharging from the tip of the siphons.In most other anatomical respects Clavagella is typical of the Anomalodesmata, the ctenidia and labial palps for example being of characteristic form. The statocysts, however, are unusual in that the statolith comprises a large number of small, diamond‐shaped crystals that stimulate statocyst cilia. C. australis appears to be dioecious, whereas most other anomalodesmatans are simultaneous hermaphrodites. Clavagella may be linked to a pholadomyacean ancestor and most closely resembles members of the infaunal Latemulidae. It represents an evolutionary line that has adopted first a nestling then a boring mode of life. It seems probable that the more specialized infaunally buried clavagellids with both valves incorporated into the adventitious tube are derived from a nestling/boring ancestor.
Octopus joubini (Mollusca: Cephalopoda): a detailed study of growth through the full life cycle in a closed seawater system
Authors: Forsythe John W. 
Published: August 2009

Twenty individual pygmy octopuses, Octopus joubini, were reared at 25°C from hatching to maturity on a quantified diet of live crabs in closed (recirculating) natural seawater systems. At 24 week intervals the animals were narcotized, weighed and measured. There was 85% survival to sexual maturity.Growth rates were highest during the first four weeks of exponential growth. Beyond four weeks, growth rates steadily declined and growth became logarithmic in form. Female octopuses grew slightly faster than males and attained a larger size at maturity. The length‐weight relationship showed male Octopus joubini to weigh more than females at a given mantle length. This species displays slight allometric growth resulting in changing body proportions through the life cycle. Relative food intake is highest at hatching and decreases with age. Mean gross growth efficiency over the life span was approximately 40%.
The response of prey to Stoat (Mustela erminea) scent
Authors: Gorman Martyn L. 
Published: August 2009

Microtus agrestis and Orcadian Microtus arvalis avoid stoat scent and show a reduction in activity when surrounded by it. Such responses probably are adaptive and decrease the chances of an individual suffering predation. Since M. arvalis has been isolated from stoats on Orkney for several millenia the response is innate.For reasons unknown Apodemus sylvaticus does not respond to stoat scent.
Taxonomy and natural history of some fossorial rodents of Patagonia, southern Argentina
Authors: Pearson Oliver P. 
Published: August 2009

Habits and taxonomy of species of the following genera are discussed: Aconaemys, Ctenomys, Chelemys, Geoxus, and Notiomys. In degree of adaptation to a burrowing mode of life, these five Patagonian genera fall between Thomomys bottae and Microtus californicus. Sympatry occurs frequently among most of the Patagonian genera, a condition permitted by dietary, size and habitat differences. The two studied species of Ctenomys remain allopatric, as well as the two species of Aconaemys.New specimens of Notiomys edwardsii confirm the uniqueness of that genus. Chelemys and Geoxus are considered to be generically distinct. Chelemys angustus is an Akodon, and Chelemyscus fossor is a composite of Chelemyscus macronyx (skin) and Euneomys (skull). Two distinct species of Aconaemys are recognized; one of them is described as new.
The population ecology of small rodents in Pennine woodlands
Authors: Gibson D. St C. , Delany M. J. 
Published: August 2009

Apodemus sylvaticus and Clethrionomys glareolus populations were studed in two mixed woodlands in the Pennine Hills; one was at the altitude of 400 m (Malham) and the other at 160 m (Coniston Cold). The former was studied for three years (1977–80) and the latter for one year (1979–80). At Malham 703 rodents were caught in the live trapping programme representing 4219 captures in 37,108 trap nights; the corresponding figures for Coniston were 259 animals, 1165 captures and 5400 trap nights.At Malham, both species were relatively numerous through spring and summer of 1977 (Apodemus 10–30/ha, Clethrionomys 6–23/ha). In later years, Apodemus had troughs from March to June (0.5–8.0/ha) and peaks from September to November (13–24/ha); Clethrionomys remained at low densities throughout this period with only, in two months, populations attaining more than 6/ha. At Coniston, Apodemus attained a density of 38.6/ha in October and Cleihrionomys 32.7/ha in August.Monthly sex ratios did not significantly differ from unity. Length of residence of Apodemus first caught (at Malham) in March‐June and October‐December did not exceed six and 16 months, respectively. Clethrionomys resided up to one year although over 80% disappeared by three months. Adult mice and voles increased their mean weight from late winter to reach maxima between April and June. The lightest animals were found from October to December.Most Juvenile mice were born between April and October. Testes were small from October to December, increased in size in January and were descended from March to October. At Malham, the months when females were pregnant varied annually, viz. 1977, April‐November; 1978, March‐September; 1979, May‐October. At Coniston breeding started earlier. Clethrionomys at Malham had a short breeding season with no pregnancies observed before June, and the first juveniles typically occurring in July (the exception being when breeding probably occurred in the winter of 1976–1977). Breeding terminated in September‐October. At Coniston it extended from April to October. Annual net production of the two species combined ranged from 9.62 MJ/ha/year to 5.02 MJ/ha/year at Malham. The Coniston figure was 17.62 MJ/ha/year.The results are discussed in relation to other woodland populations where climate is less harsh and the growing season appreciably longer.
Changes in thyroid function and gonadotrophin activity during sexual development in ducks Anas sp. (Aves: Anatidae)
Authors: Klandorf H. , Harvey S. 
Published: August 2009

Age‐related changes in plasma iodohormone concentrations in male and female Aylesbury and Khaki Campbell ducklings were determined between the second week after hatching and sexual maturity.In both sexes and strains the concentration of total thyroxine (T4) and the free thyroxine index (FT41) were low during the first 6–8 weeks after hatching. A marked increase in the T4 and FT41 occurred when the ducklings were nine weeks old; T4 progressively increased over the following four weeks and remained high thereafter. The T4 concentration in both sexes was directly related to age.Concentrations of total tri‐iodothyronine (T3) were more variable than T4 but were highest before sexual maturation and inversely age‐related. An age‐related decline in free tri‐iodothyronine index (FT31) was observed during the first nine weeks.The possibility that these maturational changes in thyroid function may reflect changes in gonadal activity was assessed by measuring the concentration of luteinizing hormone (LH) in the same plasma samples. Although plasma LH increased with age, in all cases the increase occurred after changes in the thyroid hormones were observed. Moreover, the maturational pattern of LH was related to sex and strain whereas thyroid function was unaffected by sex or strain.These results demonstrate reciprocal changes in plasma T3 and T4 levels in ducks during sexual development, although the stimuli responsible and physiological significance are uncertain.