bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth of nestling sparrowhawks (Accipiter nisus)
Authors: Moss Dorian 
Published: August 2009

Growth rates, mortality and parental care of nestling sparrowhawks were studied in southwest Scotland. Ae Forest was a conifer plantation 200–400 metres above sea‐level, while the Annan valley consisted of farmland, woods, and small plantations on low ground.Nestling sparrowhawks were measured daily from hatching for 21–24 days. Weight, tarsus length and outermost primary feather length were recorded. Nestlings could be sexed by the age of 16 days from the larger size of females, which were significantly heavier than males at one day, had longer tarsi at nine days, and longer primaries at 18 days. Growth rates were calculated using linear regression over standardized periods of about 10 days.Growth rates were independent of brood size, and were negatively correlated with hatching date in one area. Hatching order and growth rate were correlated within broods. The greatest differences in growth rates were found between zones of Ae Forest, and between forest and valley.Twenty‐one per cent of nestlings over two days old died. Causes of mortality were starvation, wet weather, predation and desertion. Most of the mortality occurred in parts of Ae Forest remote from valley woodlands.The presence or absence of the adult female was noted on nest visits. When habitually brooding, until the young were 11 days old, the hen was present on about 85% of visits. By fledging this figure fell to 66% in the valley, and to 32% in the forest.The development of sexual dimorphism is discussed; females gained weight and body size faster than males, which developed various skills sooner.It is suggested that differences in growth rates between parts of the study area were related to food supply. Poor growth rates, high mortality, and lack of parental care all occurred in areas which were remote from sources of abundant prey, as measured by song‐bird censuses.
Comparison between pars intercerebralis neurosecretory cells of Glossina and those of other higher Diptera
Authors: Panov A. A. 
Published: August 2009

Three types of the A‐neurosecretory cells (NSCs) were found in the pars intercerebralis (PI) of the adult brain of four species of tsetse flies (Glossina palpalis, G. pallidipes, G. austeni and G. morsitans). The typical formula of their composition is: 8 A1‐, 14 A2‐ and 4 A3‐cells. After permanganate oxidation, the neurosecretory materials (NSMs) of Al‐ and A3‐cells are rich in strong acid groups. The A2‐NSM contains both strong and weak acid groups after this treatment; besides, it retains a weak affinity to acid dyes. In addition to the A‐cells, the PI of Glossina species seems to include a number of NSCs of the type B.The data obtained indicate a great similarity of the NSC composition in the PI of Glossina and other related higher dipterans.In addition to the NSCs, giant neurons and particular cells with large cytoplasmic inclusions were also found in the PI of Glossina. The cells with large cytoplasmic inclusions correspond apparently to vacuolated cells previously observed in the brain of some flies. It is suggested that the considerable complication in reproductive biology which took place in tsetse flies had no effect on the composition of the NSCs in their PI when compared to that in related species with more ordinary cycles of reproduction.
The biology and systematics of a new species of Xenopus (Anura: Pipidae) from the highlands of Central Africa
Authors: Tinsley* R. C. , Kobel** H. R. , Fischberg*** M. 
Published: August 2009

A new species of clawed toad, Xenopus wittei sp. nov. is described from highland areas overlapping the borders of Rwanda, Uganda and Zaire. A comprehensive morphological analysis of the species has been carried out. X. wittei sp. nov. is very closely related to X. vestitus and both have a tetraploid chromosome complement (2n= 72), the only examples within the genus. Nevertheless, the two species may be distinguished by easily observed features, including head morphology and dorsal body colours and patterns, and are also identified by their karyotypes and mating calls.Data on distribution, ecology and parasite infection are derived from both museum collections and fieldwork in Central Africa. X. wittei sp. nov. is sympatric in parts of its range with X. vestitus, X. laevis victorianus and X. I. bunyoniensis, with up to three of the taxa sharing the same habitats. The implications of potential species interactions are discussed. Experimental hybridization has confirmed the reproductive isolation of the two tetraploid species. Parasitological studies show that they may be distinguished from one another by host specific species of the nematode Chitwoodchabaudia and from other Xenopus species by the absence of the tapeworm genus Cephalochlamys. Large scale population movements of the Xenopus species have apparently occurred in the Central African highlands during the period of available records. Sympatry observed amongst the present day representatives of Xenopus may have been an important factor in the evolution of these toads since X. wittei sp. nov. and X. vestitus are interpreted as allopolyploids, the products of interspecies hybridization.
The diurnal rhythm and the cycle of feeding and digestion in the slug Deroceras caruanae
Authors: Morton Brian 
Published: August 2009

Deroceras caruanae (Pollonera 1891) possesses an endogenous cycle of activity and inactivity entrained by the cycle of night and day. D. caruanae remains inactive on the undersurface of experimental feeding panels during daylight hours and as dusk approaches undertakes a phase of crawling bringing it into contact with food on the upper surface of the feeding panel at night. As dawn approaches, the slugs retire to the undersurface of the panel. In total darkness, the slugs lose their normal rhythm of light and dark regulated phases of activity and inactivity. The rhythm is retained (albeit out of phase with slugs experiencing a normal light‐dark sequence) in constant illumination. The relative feeding rates of D. caruanae have been correlated with this cycle of activity and inactivity.Structural and functional changes in the organs of digestion, notably the digestive diverticula, have been correlated with the cycle of night and day, the cycle of activity and inactivity and feeding. The digestive tubules undergo a sequence of cytological changes over the course of 24 hours that primarily involves the digestive cells. These cells absorb and intra‐cellularly digest food in the hours of daylight and in late evening commence–and at night complete–a process of breakdown releasing fragmentation spherules and excretory concretions into the stomach. The fragmentation spherules, by the release of unused intra‐cellular enzymes, possibly assist in the primary extra‐cellular digestion of food in the crop on the next feeding cycle.The digestive diverticula comprise three cell types; digestive cells, calcium cells and thin cells. The function of these cell types is discussed and the structure of the digestive diverticula of D. caruanae compared with that of other pulmonates.Finally a co‐ordinated scheme of the processes of activity and inactivity, and feeding and digestion is constructed showing how such processes are inter‐related and affected by environmental variables; most notable among these is the cycle of night and day.
Biology and relationships of the South African sacoglossan mollusk Volvatella laguncula
Authors: Thompson T. E. 
Published: August 2009

The oxynoaceanVolvatellaand the less well knownAscobullaandCylindrobullaare the most primitive living members of the gastropod order Sacoglossa.Volvatellais a world‐wide genus characterized by a capacious shell into which complete retraction is possible, a posterior exhalant spout‐like pallial siphon, and a sacoglossan radula.At Strandfontein near the Cape of Good Hope, large numbers of these small molluscs were found living among and feeding upon the roots of the algaCaulerpa filiformis, which forms sublittoral meadows on the coasts of southern Africa. They were identified asVolvatella lagunculaSowerby, 1894, originally described (from the shell alone) in material from Port Elizabeth. The mollusc lives and feeds in the muddy sand aroundCaulerparoots at a depth of 5 cm or more below the surface. The captured material proved to be hermaphrodite, sexually mature and to have mated, but no spawn was found. An interesting feature of the reproductive organs was an epidermal ciliated gutter extending along the right flank from the female opening past the male opening on to the side of the head; this is interpreted as an oviducal groove conducting the egg‐stream during oviposition (as has been suggested for the Japanese juliaceans). A similar groove was found on the left side but its function is unknown.The mantle cavity contained a plicate gill; irrigation was brought about by adduction movements which rhythmically deformed the outer lip of the shell. A strong transverse muscle was present and was responsible for these movements. It is evidently homologous with the adductor muscle of the bivalved juliaceans. It is likely that what is pumped through the mantle cavity ofVolvatellais an ooze of fine mud.Volvatella, together withCylindrobullaandAscobulla, constitutes a link between the infaunal proto‐opisthobranchs and the present‐day epifaunal herbivorous Sacoglossa.An annotated list of the world's species ofVolvatellaconcludes the paper.
The structure of the gills and lungs of the arid‐zone crab, Holthuisana (Austrothelphusa) transversa (Brachyura: Sundathelphusidae) including observations on arterial vessels within the gills
Authors: Taylor H. H. , Greenaway Peter 
Published: August 2009

Structural adaptations of the branchial apparatus of Holthuisana (formerly Parathelphusa) transversa (Martens) for bimodal gas exchange and ion uptake are described using optical and electron microscopy.A single epithelial cell type (besides pillar cells) in the gill lamellae fulfils the dual role of ion uptake from freshwater and aquatic gas exchange. The total blood/water distance is about 5–8 μm (cuticle 2–3 μm, cells 2–5 μrn). Apical cellular extensions delimit an extensive system of subcuticular spaces. Mitochondria are numerous in the sub‐apical cytoplasm but do not form “mitochondrial pumps” with the weakly developed basal infoldings. Nephrocytes are present in the gill shaft but not in the lamellae. Each gill possesses two arteries termed epibranchial and hypobranchial arteries), which run parallel and medial to the main afferent and efferent vessels, and which branch extensively in each lamella (lamellar arteries). The multi‐layered endothelial wall of the arteries forms a longitudinally pleated intima. Larger arteries possess an external collagenous sheath. Sheath and intima are absent from the terminal capillaries. It is suggested that the arteries supply oxygen to the metabolically active tissues of collapsed gills during aerial respiration.The branchiostegites are expanded to form lungs which are ventilated by a unique tidal mechanism involving lateral movements of the thoracic wall. The inner cuticular lining of the branchiostegite is smooth and the epidermal cells extremely attenuated. The total blood/ gas distance is only 250–300 nm (cuticle 200–250 nm, epidermal cell extensions 20–50 nm, basal lamina 30–40 nm) and comparable with the lungs of higher vertebrates. Deoxygenated systemic blood is directed close to the gas exchange surface by newly‐described fimbriated cells bordering the connective tissue partitions separating fine afferent and efferent blood sinuses.The observations are discussed in detail in relation to general features of the structure of crustacean gills, branchiostegites and permeable cuticles and of crustacean circulatory and respiratory physiology.
The social display of the Chilean teal Anas flavirostris flavirostris
Authors: Standen* P. J. 
Published: August 2009

Filmed episodes of social display in the Chilean teal were analysed in order to throw light on the function of social display in surface‐feeding ducks and the role the female plays in this activity. Four different methods were used to study the associations between different behaviour patterns in several individuals. It appears that the behaviour patterns comprising social display fall into three groups which are described as “attention getting”, “close‐range” and aggressive. It is proposed that social display allows unpaired males to attract the attention of females in an attempt to establish a pair‐bond through the use of the “close‐range” behaviour patterns. This forces paired males to compete in “attention‐getting” behaviour patterns. Aggression results from this competition and from the threatening presence of unpaired males when the paired males try to strengthen their pair‐bonds with the use of the “close‐range” behaviour patterns.Females play an influential role as their behaviour links the “attention‐getting” behaviour with the “close‐range” and aggressive behaviour. Their “close‐range” behaviour suppresses that of other females.
Growth in pygoscelid penguin chicks
Authors: Volkman N. J. , Trivelpiece W. 
Published: August 2009

A study of sympatrically breeding Adelie (Pygoscelis adeliae), Chinstrap (P. antarctica), and Gentoo (P. papua) penguins was undertaken on King George Island, South Shetland Islands to compare their rates and patterns of growth, and to relate these findings to pygoscelid breeding ecology. In contrast to other large oceanic birds, the logistic equation best described the biomass growth of pygoscelid penguins, as it did their culmen and flipper growth. Growth constants were 0146, 0127 and 0113; asymptotic weights were 3940 g, 4025 g and 5715 g for Adelie, Chinstrap and Gentoo penguins, respectively. Growth of feet and flippers was more rapid than culmen growth.Among the pygoscelids, the Adelie penguin has the most southern breeding range, the Gentoo the most northern; while the Chinstrap penguin's range is approximately intermediate to its congeners. In this and other studies, pygoscelid penguins show both an inverse correlation between their growth constants and asymptotic weights, and between their asymptotic weights and latitudinal distributions. Mean adult weights, however, are not correlated with latitudinal distributions as adult Adelie penguins weigh more than adult Chinstrap penguins. It is suggested that lower asymptotic weights are advantageous in the shorter breeding seasons found at higher latitudes.The similarity of growth rates of Adelie and Chinstrap penguins to day 37, and the decrease of the rate at which Chinstraps grow thereafter, does not support the hypothesis that Chinstrap penguin growth rates are retarded due to food competition with the Adelie penguin in areas of sympatry. The preponderance of krill (Euphausia spp.) in the diet of all these pygoscelid penguins suggests that differences in growth or survival rates resulted from factors other than dietary differences. Due to lack of available data, other such variables affecting survival and growth rates (e.g. predation, foraging strategies) could not be assessed.Recently pygoscelid penguin populations have expanded, probably in response to increased food resources. Adelie and Chinstrap populations have increased more rapidly than Gentoo populations. It is suggested that the lower rate of increase of Gentoo populations reflects basic differences in ecological strategies among pygoscelids, as evidenced by their growth patterns.
Ultrastructural features of the light organs of Histioteuthis macrohista (Mollusca: Cephalopoda)
Authors: Dilly P. N. , Herring P. J. 
Published: August 2009

The general morphology and ultrastructure of the epidermal and arm tip photophores of H. macrohista have been compared. Both types of photophore have similar structuresand the photocytes of each are characterized by dense aggregations of endoplasmic reticulum. The filter region of the epidermal photophores contains protoporphyrin.
Mammal tracking and nest location in Brazilian forest with an improved spool‐and‐line device
Authors: Miles M. A. , de Souza A. A. , Póvoa M. M. 
Published: August 2009

Spool‐and‐line mammal tracking devices, with a range of up to 2300 m, were constructed and used to trace Brazilian forest mammals. A retrieval rate of 64.6% was achieved with263 animals of 16 species. Detailed observations of nests or refuges and behaviour were possible, which contributed to an understanding of the ecological segregation of the species. It was demonstrated that spool‐and‐line tracking was a valuable, neglected procedure, with some advantages over other methods, that could become an integral part of routine investigations of mammal ecology.
Elastic energy storage in the hopping of kangaroo rats (Dipodomys spectabilis)
Authors: Biewener A. , Alexander R. McN. , Heglund N. C. 
Published: August 2009

Bipedal hopping of kangaroo rats has been studied by making force plate records and X‐ray cinematograph films simultaneously. Calculations using the data so obtained, andanatomical data, show that energy saving by elastic storage is much less important thanin kangaroos.
The functional morphology of the branchial chambers and associated structures of Ebalia tuberosa (Crustacea: Decapoda: Leucosiidae), with special reference to ventilation of the egg‐mass
Authors: Schembri Patrick J. 
Published: August 2009

Ebalia tuberosa bury themselves in sediment but do not construct permanent burrows. There are no functional Milne‐Edwards' openings, the respiratory currents passing along channels formed by apposition of several interlocking buccal appendages. In adult females, the dome‐like abdomen fits over the concave sternum to form a large abdominosternal chamber which completely encloses the egg‐mass. The branchial chambers are connected tothe abdominosternal chamber by two branchiosternal canals plugged by modified pericardialsacs which act as one‐way valves. When the telson is extended, water is sucked into the abdominosternal chamber and then into the branchial chambers, thus ventilating the eggmass. The setation of the respiratory and associated structures serves to lock appendagestogether, to form screens and gaskets and to groom the buccal appendages. Setal morphology is shown to be correlated with function.
The Geonemertes problem (Nemertea)
Authors: Moore Janet , Gibson Ray 
Published: August 2009

A new genus of monostiliferous hoplonemerteans, Pantinonemertes gen. nov., provides evidence for the separate evolution of terrestrial nemerteans. The genus is established for two new species found in Australia, P. enalios sp. nov., an intertidal form, and P. winsori sp. nov., which lives in fallen timber in the supralittoral brackish water regions of mangrove swamps. One only of the known species of land nemerteans, Geonemertes agricola from Bermuda, closely resembles these two species morphologically and is transferred to the new genus as Pantinonemertes agricola.A re‐examination of all the known species of Geonemertes has shown that two major groups can be distinguished on the basis of morphological characters. In one group the rhynchocoel musculature is in two distinct layers, a frontal organ is present, the mid‐dorsal blood vessel has a single vascular plug, and the flame cells are binucleate and reinforced with cuticular support bars. It comprises the genus Pantinonemertes gen, nov, and the Pelaensis or Indopacific group of terrestrial nemerteans, for which the generic name Geonemertes is retained. In the second major group the rhynchocoel musculature is composed of interwoven longitudinal and circular fibres, there is no frontal organ, the mid‐dorsal blood vessel bears two vascular plugs, and the flame cells are mononucleate and lack support bars. Five genera, three of which are new, are distinguished in this group. Australian species are united in the genus Argonemertes gen. nov., and New Zealand forms comprise the genus Antiponemertes gen. nov., while Acteonemertes bathamae from New Zealand and the Auckland and Ocean Islands remains in a separate genus. Geonemertes nightingaleensis is transferred to a new genus, Katechonemertes gen. nov., and for Geonemertes chalicophora a previously used generic name, Leptonemertes, is adopted.A key to the terrestrial, brackish‐water and marine nemertean species described in the present paper is provided.
Reproductive biology of the Red‐necked wallaby (Macropus rufogriseus banksianus) and Bennett's wallaby (M. r. rufogriseus) in captivity
Authors: Merchant J. C. , Calaby J. H. 
Published: August 2009

Bennett's wallaby (Macropus r. rufogriseus) of Tasmania give birth from late January to early August in marked contrast to the Red‐necked wallaby (M. r. banksianus) of mainland south‐eastern Australia which produced young in all months. Within the breeding season however, the lengths of the oestrous cycle and gestation period are similar in the two forms and did not differ by more than 0.5 days. The gestation period of about 30 days extended to almost the length of the oestrous cycle of approximately 33 days. Birth was closely followed by mating which normally resulted in fertilization and subsequent embryonic diapause. Renewed blastocyst development was initiated by removal or loss of a pouch young and birth followed about 27 days later.Unlike other macropodids with a similar breeding pattern, birth, as a result of renewed blastocyst development near the end of a large young's pouch life, did not occur within a day or two of the permanent emergence of the young, but followed 16 to 29 days later. InM. r. rufogriseus, young that left the pouch permanently in the non‐breeding period were not replaced by new young until the beginning of the next breeding season two to four months later, and blastocysts resulting from mating of females without pouch young at the end of the breeding season remained quiescent until the next breeding season five to eight months later.Females of both subspecies first mated at an age of about 14 months, and males were producing mature spermatozoa by about 19 months.Young first left the pouch for short periods at about 230 days of age and permanently at about 280 days.Observations are also given on reproductive behaviour, interpretation of vaginal smears, sex ratio of young, selection of teat by pouch young, and development of morphological features in known‐age young that may be used as an aid in age determination.
Seasonal breeding, moulting and weight changes among birds of dry deciduous forest in North India
Authors: Gaston A. J. 
Published: August 2009

The timing of breeding among Indian birds varies between species and also regionally within species. Marked differences can occur between adjacent areas, depending on the seasonal availability of moisture for plant growth. Birds of dry deciduous woodland have two peaks of breeding activity, in spring (March‐April) and during the rains (July‐September), with moult following the second peak in most cases. Rates of moult vary greatly between species, but practically all terminate moult by the end of November and this may truncate the potential breeding season for some species.Changes in weight show a marked contrast with seasonal patterns observed in temperate latitudes, weights being inversely correlated to mean temperature. It is suggested that, in the case of some species which occupy a wide range of vegetation types, observed patterns of breeding and moulting are a compromise between the optimum strategies for different habitats.