bluuebunny/crossref_metadata_2025 huggingface dataset:
Satellite tracking of grey seals (Halichoerus grypus)
Authors: McConnell B. J. , Chambers C. , Nicholas K. S. , Fedak M. A.
Published: March 2009

Three types of Argos satellite transmitter were attached to grey seals (Halichoerus grypus) at Donna Nook (South Humberside, UK) between 1985 and 1989 in order to investigate their movements. With the first two transmitters (A and B) the entire package was attached to the seal's back. Seal A was tracked for 29 days but although it was located on sandbanks up to 150 km south‐east of Donna Nook, no locations were obtained at sea. Transmitters B and C used a submergence sensor to regulate transmissions. Seal B was tracked for 51 days and remained within 40 km of Donna Nook. A few locations were obtained at sea but all within 10 km of Donna Nook. Transmitter C incorporated a head‐mounted aerial in order to increase the number of location fixes when the seal was at sea. This seal was tracked for 111 days, producing an average of 9·1 location fixes per day while at sea. It used two sites 265 km apart and undertook three transits between them. On the second visit to the northern site it made several trips up to 55 km out to sea. The majority of the remainder of the time was spent within 10 km of the haulout sites. Estimates of swimming speed were consistent with values required for minimum cost of transport.
Heritability of male outcrossing ability in the simultaneous hermaphrodite, Bulinus truncatus (Gastropoda: Planorbidae)
Authors: Schrag Stephanie J. , Rollinson D. , Keymer Anne E. , Read A. F.
Published: March 2009

The heritability of phally, a dichotomous trait defined by the functional state of the male reproductive tract, was measured in a laboratory population of the simultaneous hermaphrodite snail Bulinus truncatus by means of a breeding experiment and a selection experiment. Euphallic individuals develop a fully functional male and female tract and are capable of receiving and donating sperm. In aphallic individuals the male tract does not develop fully, preventing sperm donation. There was no evidence of a heritable component to phally in the breeding experiment, but the selection experiment demonstrated a slight heritable effect. In both experiments there was more variation in the observed proportion of euphallics than expected by chance alone and no evidence of line or family effects, implicating environmental determination of male outcrossing ability even under controlled laboratory conditions. Previous studies of populations of B. truncatus reported that the proportion of euphallics was under strong genetic control. We suggest that there may be population differences in the extent of environmental control over phally, analogous to that reported for sex determination.
Locomotory activity in the Namib Desert golden mole Eremitalpa granti namibensis (Chrysochloridae)
Authors: Fielden L. J. , Hickman G. C. , Perrin M. R.
Published: March 2009

Eremitalpa granti namibensis is a small, blind, subterranean insectivore endemic to the Namib Desert sand dunes. Unlike other subterranean mammals which seldom leave their burrow systems, the Namib mole forages extensively on the dune surface for its insectivorous prey. Activity phasing in this atypical mole was examined in the field and in the laboratory. Free‐living moles were almost exclusively nocturnal, while moles kept in the laboratory were active day and night. These findings are discussed in relation to prey availability, predator pressure and avoidance of diurnal extremes. Light and temperature appeared to be important cues for daily onset and cessation of activity.
Studies on skeleton formation in reptiles. I. The postembryonic development of the skeleton in Cyrtodactylus pubisulcus (Reptilia: Gekkonidae)
Authors: Rieppel Olivier
Published: March 2009

The study of ossification during postembryonic development of the lizard Cyrtodactylus pubisulcus reveals consistent patterns in the skeleton of the body axis and of the limbs. The vertebral column shows a distinct antero‐posterior gradient in ossification; the serial homology of sacral ribs and caudal transverse processes with dorsal ribs requires further scrutiny. The sequence of ossification of carpal and tarsal elements is constant, yet different from the pattern of chondrification as described in the literature. The homology of a separate ‘intermedium’ in the ossified lizard carpus requires further discussion. The development of the lizard astragalus is discussed in detail, as is the ossification of epiphyses in the limbs.
The m. caudifemoralis longus and its relationship to caudal autotomy and locomotion in lizards (Reptilia: Sauna)
Authors: Russell A. P. , Bauer A. M.
Published: March 2009

Although the phenomenon of tail autotomy has traditionally been viewed in a purely adaptive light, functional constraints imposed by the locomotor system appear to have influenced the presence and extent of autotomy in lizards. Them. caudifemoralis longus is an unsegmented hind limb retractor that originates from the caudal vertebrae. It does not participate in autotomy and thus limits the proximal position of autotomic septa. Variation in the extent of the m. caudifemoralis is correlated with locomotor type. The muscle is large and originates from a long series of caudal vertebrae in fast moving lizards with powerful limb retraction, as exemplified by taxa capable of bipedal running. In slower lizards with sprawling postures, such as geckos, the m. caudifemoralis is small and restricted to the first few postsacral vertebrae. Autotomy is typically restricted or absent in the former lizards, while in the latter only the most proximal vertebrae are incapable of autotomy. In the evolution of existing patterns of caudal autotomy, functional demands intrinsic to the tail may be subservient to locomotor constraints imposed on the tail base by the m. caudifemoralis longus.
Seasonal patterns in water, sodium and energy turnover in free‐living echidnas,Tachyglossus aculeatus(Mammalia: Monotremata)
Authors: Green B. , Griffiths M. , Newgrain K.
Published: March 2009

The energetics of an egg‐laying mammal, the echidna (Tachyglossus aculeatus), were studied in the wild by means of isotope turnover techniques. Water and sodium influx rates were highest in summer (47.7±15.3 ml kg‐1day‐1and 1.20±0.52 mmol kg‐1day‐1, respectively) and associated with high metabolic rates (0.509±0.048 ml CO2g‐1h‐1). Water and sodium influxes and metabolic rates were lowest in May and June (7.8±6.4 ml H2O kg‐1day‐1, 0.21±0.12 mmol Na kg‐1day‐1and 0.205±0.129 ml CO2g‐1h‐1, respectively). These low rates in late autumn/early winter are associated with reduced activity, the animals spending substantial periods of time in torpor. The comparatively low isotope turnover rates of echidnas are a consequence of their diet; ants and termites which have low mass‐specific energy contents.
Bill morphology and diet of a filter‐feeding seabird: the broad‐billed prion Pachyptila vittata at South Atlantic Gough Island
Authors: Klages Norbert T. W. , Cooper John
Published: March 2009

One hundred and fifty diet samples collected from broad‐billed prions Pachyptila vittata at South Atlantic Gough Island and Tristan da Cunha over four years during the breeding season showed that they fed almost exclusively on copepods (0.7–4.1 mm in size), consistent with a bill morphology adapted for filter‐feeding. Food is sieved from the surface of the ocean by means of palatal lamellae, of which there are 112–136 on either side, 0.16 mm apart. The filtration area of both rows of lamellae together amounted to 785 mm2 and the bill held 4.1 ml of water with a maximally extended mandibular pouch. Both sexes of broad‐billed prions look outwardly alike but morphometric measurements proved that males are slightly larger.
Spatial organization and monogamy in the mara Dolichotis patagonum
Authors: Taber A. B. , Macdonald D. W.
Published: March 2009

Maras, Dolichotis patagonum, were observed and radio‐tracked in Argentina. They travelled as monogamous pairs that bred either alone at solitary burrows or communally at settlements where up to 29 pairs shared warrens.

Members of a mara settlement grazed within 2.5 km of the communal warrens, using intensively about 1 ha per day, within drifting daily ranges of 11 ha, seasonal ranges of 98 ha and annual ranges of 193 ha.

Their home ranges drifted continuously. Consequently, the long‐term movements of neighbouring pairs overlapped substantially, but at any given moment they were territorially spaced.

Monogamous, drifting territoriality is explained by the patchy dispersion of food, the need to minimize interference competition, and a cycle of grazing and fallowing in the use of food plants.

Two hypotheses explaining the adaptive significance of settlements are evaluated: one relates to resource availability (through the indirect effect of ground water and sheep dung on vegetation); and the other relates to predation (through the protective influence of human dwellings). The size of sheep flocks grazing at outstations during January provide a measure of the resource richness of patches where maras graze, and the richness of these patches in the dry season appear to limit the number of maras breeding at each settlement during the following wet season.

Maras face extremes of resource dispersion between the wet and dry seasons: in the former, sparsely dispersed grazing and interference competition favour spacing out and territoriality; in the latter, clumping of resources facilitates pairs congregating in herds around outstations and dry lagoons. Superimposed upon the ecological factors favouring spacing out during the wet season are the sociological factors that cause the maras to den communally. The resulting compromise is a social system unique among mammals.
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.
Dyar's rule and multivariate allometric growth in nine species of waterstriders (Heteroptera: Gerridae)
Authors: Klingenberg C. P. , Zimmermann M.
Published: March 2009

The constancy of postmoult/premoult ratios of measures of linear size during ontogeny in insect and other arthropods is widely known as Dyar's rule. We tested this rule in nine species of the waterstrider genera Gerris and Aquarius (Heteroptera: Gerridae), using two size variables: head width and a multivariate measure derived from the pattern of multivariate allometry common to the species considered. Allometric patterns were similar in two independent datasets of laboratory‐reared and field‐caught specimens. Although our data strictly followed Dyar's rule injust a few instances, all growth ratios varied within a limited range only. Growth ratios for head width differed more between moults than those for multivariate size. The relationship between growth ratios for the two size measures conformed to the predictions based on allometry. We discuss hypotheses of the possible adaptive significance of growth ratios, such as their relation to mobility and systematic differences between hemimetabolous and holometabolous insects, and emphasize the importance of allometry. Since Dyar's rule is consistent with available evidence of physiological mechanisms underlying growth and moulting control of insects and crustaceans, it can be used as a general frame of reference to test alternative growth models.
Initial development of Oreochromis niloticus (Teleostei: Cichlidae) otolith
Authors: Zhang Z. , Runham N. W.
Published: March 2009

Otoliths of Oreochromis niloricus initiate as separate protein granules, surrounded by numerous dark particles. These granules merge to form the sub‐primordium, after a layer of calcium and a layer of protein has been added to each one. Large amounts of protein are accreted on to the subprimordium to form the primordium. Calcification takes place shortly afterwards. In the otocyst lumen filaments and vesicles are abundant and associated. They seem to contribute to the proteins of the primordium and the calcified otolith. Mitochondria, Golgi complexes and intracellular granules are abundant in the epithelium, from which vesicles extrude.
The feeding biology of the immigrant triclad Phagocata woodworthi in Loch Ness, Scotland
Authors: Young J. O.
Published: March 2009

Laboratory feeding experiments and a serological examination of the gut contents of field‐collected triclads indicated that Phagocata woodworthi Hyman feeds heavily on oligochaetes. Its realized food niche also includes Asellus, caddisflies, molluscs, chironomids, stoneflies and mayflies. It is concluded that Ph. woodworthi is a considerable threat to the British triclad fauna, because of the considerable overlap in diet with native species, its fast reaction time to damaged prey, and its polypharyngeal state.
Occurrence of bats in northernmost Sweden (65°N) and their feeding ecology in summer
Authors: Rydell J.
Published: March 2009

The population density of the northern bat Eptesicus nilssoni at 65° N was about one‐fifth of that in southern Sweden (57° N). No other bat species was observed at 65° N. In one maternity colony, young northern bats were born in July and were flying by early August. The diet consisted mainly of small insects, predominantly dipterans, which were captured and eaten in the air. The bats maintained a nocturnal (22:00–02:30 h) foraging schedule in summer, partly reflecting the activity of insects, and spent about three hours away from the day roost each night. Owing to the short periods of darkness, the foraging flights usually started and ended in daylight. Habitat use reflected the occurrence of small insects near vegetation.
Predator‐prey interactions between web‐invading jumping spiders and two species of tropical web‐building pholcid spiders, Psilochorus sphaeroides and Smeringopus pallidus
Authors: Jackson Robert R.
Published: March 2009

Psilochorus sphaeroides from Queensland, Australia and Smeringopus pallidus from Sri Lanka are long‐legged, web‐building pholcid spiders with a special defence behaviour, whirling. The efficiency of whirling as a defence against web‐invading jumping spiders (Salticidae) was examined in the laboratory. Three salticid species were used in these tests‐Euryattus sp., Portia fimbriata and Portia labiata. Euryattus leapt into webs, but Portia fimbriata and Portia labiata walked slowly into webs and practised aggressive mimicry. Portia fimbriata was more consistent at using aggressive mimicry and more efficient at capturing Psilochorus sphaeroides and Smeringopus pallidus than was Portia labiata. Both species of Portia were more efficient at catching pholcids than was Euryattus. Portia, especially Portia fimbriata, was less inclined than Euryattus to stimulate pholcids to whirl. In an experiment in which pholcids were artificially induced to whirl whenever a salticid was near, salticids never captured pholcids, providing additional evidence that whirling is an effective defence of Psilochorus sphaeroides and Smeringopus pallidus against web‐invaders. Results from this study are compared to those from a study of another pholcid that whirls, Pholcus phalangioides.
Use of tooth impressions to identify and age live Proechimys guyannensis and P. cuvieri (Rodentia: Echimyidae)
Authors: Malcolm J. R.
Published: March 2009

A technique whereby impressions of the cheekteeth were used to identify and age live Proechimys guyannensis and P. cuvieri is presented and tested. Based on tooth eruption and occlusal surface wear, 15 age classes were defined. Used in concert with a body measurement, measurements of the length of the toothrow and age class allowed almost all live individuals of the two species to be distinguished. The relationship between mean cheektooth length and hind foot length was most useful for distinguishing relatively old individuals, whereas the relationship between hind foot length or head‐plus‐body length and toothrow age class was most useful for distinguishing younger individuals. Mean eye lens weight of P. guyannensis increased with toothrow age class, suggesting that the toothrow age classes successfully measured relative age. Individuals of P. guyannensis in lower age classes had juvenile or subadult pelage and did not show signs of reproductive activity, whereas individuals in higher age classes had adult pelage and approximately 50% showed signs of reproductive activity. In the central Amazon, P. cuvieri was found to be proportionally more abundant relative to P. guyannensis in early‐successional and edge‐dominated habitats.
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.
Tracheal diverticula in snakes: possible functions and evolution
Authors: Young Bruce A.
Published: March 2009

The structural features of tracheal diverticula are reviewed, and their taxonomic distribution summarized. Five possible functions are hypothesized for these structures: as an air reservoir, as an accessory site for gas exchange, to enhance buoyancy, to inflate the neck, and to modify the hiss acoustically. Three possible scenarios for the evolutionary origin of tracheal diverticula are discussed: through simplification of tracheal lungs, through subdivision of expanded tracheal membranes, and as de novo structures. The tracheal diverticula most likely function concomitantly to inflate the neck and acoustically modify the hiss. These structures presumably arose de novo, in either one or two evolutionary lineages.
Mass changes of grey seal Halichoerus grypus pups on Sable Island: differential maternal investment reconsidered
Authors: Bowen W. D. , Stobo W. T. , Smith S. J.
Published: March 2009

Theory predicts that where variance in reproductive success differs between sexes, as in many sexually dimorphic species, mothers should invest more in male than in female offspring. In pinnipeds, parental investment is the sole responsibility of the mother. Both size at birth and subsequent mass gain during lactation are measures of that investment. We studied mass gain of grey seal pups, a sexually dimorphic species, during lactation and mass loss during the first 13 days of the postweaning fast using longitudinal data obtained on Sable Island, Canada. A mixed‐effects repeated measures model was used to account for the serial correlation in these longitudinal data. We found no significant difference in the birth mass of male (16.6 ± 0.45 kg) and female (15.6 ±0.74 kg) pups. Rate of mass gain by males (3.0 ± 0.13 kg/d) and females (2.7 ± 0.12 kg/d) also did not differ significantly during the lactation period. Grey seal pups on Sable Island tended to be larger at birth and gain mass more rapidly (70%–100%) during lactation than those in the United Kingdom. Mass loss of weaned pups was curvilinear over time. Over the first 10 days of the fast, pups lost 22% of their weaning mass. In both males and females, large pups lost mass more slowly than small ones during the postweaning fast. Based on our results and a review of previous studies, we found little evidence of differential maternal investment in male and female grey seal pups.
Early growth and sucking behaviour of Soay sheep in a fluctuating population
Authors: Robertson A. , Hiraiwa‐Hasegawa M. , Albon S. D. , Clutton‐Brock T. H.
Published: March 2009

Annual variation in growth rate and sucking behaviour of lambs was studied in a fluctuating population of Soay sheep on Hirta, St. Kilda. Growth rates during the summer declined with increasing population size in the previous autumn despite an increase in time spent sucking in the first six weeks of life. The increase in time spent sucking was due largely to an increase in sucking frequency and, since a higher proportion of sucking attempts were rejected, probably reflected that lambs obtain little milk as a result of poor maternal condition following winters at high population density. After accounting for the density dependent variation, annual differences in lamb growth rates were positively related to the increase in biomass of live grasses and forbs between spring and summer. Since food availability was influenced strongly by the numbers surviving the winter, lambs born after the very high mortality at peak population density were able to compensate to some extent for their poor initial growth. However, improved food availability was never sufficient to facilitate complete catch‐up growth and may permanently influence adult size and reproduction.
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.
Canine tooth fracture in two Congolese gorillas
Authors: Cave A. J. E. , Jones T. S.
Published: March 2009

A unique instance of fracture of all four canine teeth in the wild‐living Congolese gorilla is described. The mishap is attributed to the biting of some exceptionally hard substance in the food‐material.
Variable tensility of the oral arm plate ligaments of the brittlestar Ophiura ophiura (Echinodermata: Ophiuroidea)
Authors: Wilkie I. C.
Published: March 2009

The oral arm plates of the brittlestar Ophiura ophiura L. are connected to lateral arm plates at distal and proximal ligamentous junctions. The distal junction is mobile and is disrupted during arm autotomy; the proximal junction is more rigid and does not participate in autotomy. Aspects of the morphology and mechanical properties of the distal and proximal oral arm plate ligaments have been investigated in order to determine if their tensility is under physiological control. By means of creep tests it was found that elevation of the external potassium (K+) ion concentration causes a decrease in the viscosity of the distal ligament which is either transient or continues until rupture intervenes. In forced vibration tests the distal ligament often shows a biphasic stiffening then softening response to excess K ‐ ions. Anaesthetics block the softening phase but enhance the stiffening component of this response. This ligament is also softened by repetitive electrical stimuli but stiffened by excess calcium ions and by acetylcholine. The proximal ligament appears to have the capacity for only transient changes in mechanical properties. Both ligaments are penetrated by the processes of juxtaligamental cells whose perikarya are arranged in clusters innervated by hyponeural nerves. These cells are thought to modulate the interfibrillar cohesion of the ligaments. It is concluded that the distal and proximal ligaments are mutable collagenous structures which in their stiffened condition help to maintain arm posture without the need for continuous muscular activity, and that at autotomy the distal ligament undergoes a profound loss of tensile strength which facilitates arm detachment.
Bullia digitalis (Gastropoda) actively pursues moving prey by swash‐riding
Authors: Odendaal F. J. , Turchin P. , Hoy G. , Wickens P. , Wells J. , Schroeder G.
Published: March 2009

An individual's success at locating resource items is largely determined by the manner in which it searches. Studies on the movement trajectories of individuals have therefore been useful in elucidating mechanisms by which animals find their resources. Studies thus far have concentrated on animals that live in physically stable environments and search for stationary food items. Several of these studies revealed a surprising ineptitude of individuals in locating their resources. Our study on the other hand focuses on an animal living in a highly turbulent environment that needs to locate moving food items. We studied Bullia digitalis, a whelk that lives in the surf and swash zones of sandy beaches. In spite of constraints imposed by wave action on its movement and obvious difficulties in using positive chemotaxis in a turbulent environment, B. digitalis appears to be most efficient in tracking its prey through the surf. It uses wave‐generated flow in a form of locomotion called swash‐riding which is commonly used by a wide variety of sandy beach invertebrates.
Mating system and ecology of black Iechwe (Kobus: Bovidae) in Zambia
Authors: Thirgood S. J. , Robertson A. , Jarvis A. M. , Belbin S. V. , Robertson D. , Nefdt R. J. , Kamweneshe B.
Published: March 2009

The mating system and ecology of black lechwe Kobus leche smithemani was studied in the Bangweulu Basin, northern Zambia. Black lechwe were migratory and concentrated at high density during the wet season on shallow water floodplain and peripheral grassland. Female lechwe were evenly distributed in small groups within the two major habitat types, and density was related to water depth and the quality of vegetation. A proportion of the adult male population defended small, contiguous, resource‐based territories of approximately 1–2 ha in size. Particularly high density concentrations of male and female lechwe occurred on small raised areas, which remained dry in comparison to the inundated floodplain. These areas superficially resembled the leks of other reduncine antelope. However, the presence of vegetational resources and the comparatively low levels of agonistic and sexual behaviour suggested that raised areas were clusters of resource‐based territories. We suggest that the absence of lek‐breeding in this high density population of lechwe is related to the homogeneity of vegetational resources and the corresponding even distribution of females. This may have led to a reduction in male harassment of oestrous females and the increased ability of males to retain oestrous females within single resource territories.
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.
Intestine lengths of Southern African savanna rodents and insectivores: intra‐ and interspecific comparisons
Authors: Korn Horst
Published: March 2009

Comparative intestine lengths of 15 Southern African savanna rodents and insectivores are presented. Differences in relative intestine length (ratio between hind gut length to head/body length) between seasons were significant in Aethomys chrysophilus. In various species, breeding females, with their increased energy requirement, had hind gut lengths that were well above average. These females also accounted for the differences between sexes which were significant in two species (Aethomys chrysophilus and A. namaquensis). Within species no correlation was found between relative intestine length and body size (length and weight) of the animals. Between species the correlation was significant and the larger species had relatively longer intestines. Three groups can be distinguished according to the different feeding types of the species. The omnivorous Praomys natalensis has by far the longest intestine. It is followed by a group of species that can be considered as granivore/herbivore. The species that are partly or predominantly insectivorous have the shortest intestine. The results of the field study are found to be in agreement with reports from laboratory experiments concerning adaptations of intestine length to different environmental situations.
Seasonal variation in body composition and morphology of adult muskrats in central Saskatchewan, Canada
Authors: Virgl J. A. , Messier F.
Published: March 2009

We quantified seasonal variation in body composition and morphology of adult muskrats (Ondatra zibethicus) inhabiting freshwater marsh environments in central Saskatchewan, Canada. The study areas were characterized by long and cold winters extending over six months during which muskrats were restricted to foraging under ice. A total of 162 adult muskrats were collected during nine sampling periods across the year. The large accumulation of fat reserves (16% of body mass) during winter and the concurrent decline in protein mass suggested a reduced maintenance requirement associated with the presence of energy‐rich food resources. Dietary fibre content increased significantly during mid‐summer and was manifested by changes in gut morphology. Mobilization of fat reserves during summer months by both sexes reflected high energetic demands for reproduction. Males depleted fat reserves soon after spring break‐up, while near‐exhaustion of fat reserves in females occurred 4–6 weeks later, during lactation. Pregnant females contained significantly greater fat and protein reserves compared to non‐pregnant and lactating females. The dynamics of body reserves in muskrats should be viewed as an integral part of the sex‐specific life‐history traits of this important herbivore species of marsh environments.
Predator‐prey interactions between web‐invading jumping spiders and Argiope appensa (Araneae, Araneidae), a tropical orb‐weaving spider
Authors: Jackson Robert R.
Published: March 2009

A range of web‐invading jumping spiders with different predatory strategies was tested with A. appensa in the laboratory: Mimetus maculosus (Mimetidae), Pholcus phalangioides (Pholcidae), Taieria erebus (Gnaphosidae), and 11 species of salticids. Spiders that are known to specialize at web‐invading, either by leaping into webs or by walking slowly into webs and practising aggressive mimicry, captured A. appensa; three salticid species not known to be web‐invaders never did. Web‐invaders that practised aggressive mimicry were more efficient than were species that only leapt into webs. Portia fimbriata from Queensland was the most consistent at using aggressive mimicry and was also the most efficient at catching A. appensa. Web‐invaders that were more efficient at catching A. appensa were also better able to avoid setting off pumping, a special defence behaviour used by A. appensa. Portia fimbriata from Queensland was especially efficient at avoiding setting off pumping: P. fimbriata more consistently than other Portia made its final approach toward A. appensa by coming down from above the web on a dragline and making minimal contact with the web. An experiment, in which A. appensa was artificially induced to pump whenever the predator was near, provided additional evidence that pumping is effective in defending A. appensa against web‐invaders.
Interspecific competition and the evolution of plumage‐colour variation in three closely related old world flycatchers Ficedula spp
Authors: Røskaft E. , Järvi T.
Published: March 2009

When closely‐related species are sympatric, there will be a coevolutionary selection pressure for species‐specific characteristics to be developed, e.g. in plumage‐colour. Because the three European Ficedula flycatchers have similar ecological requirements, we expected that some kind of interspecific signalling system had been evolved in sympatric regions of species of this genus. By using museum specimens we studied the seasonal and geographical variations in plumage‐colour of the males of the three European species of the genus, and found that in areas of sympatry with F. albicollis, the subdominant species, F. hypoleuca, was lighter coloured than in allopatric areas. The plumage‐colour of F. hypoleuca gradually changes from light in sympatric areas to dark in allopatric areas. A similar pattern was found for the eastern species F. semitorquata. The results of this paper, therefore, support the character displacement hypothesis.
Effects of body size and timing of reproduction on reproductive success in female natterjack toads (Bufo calamita)
Authors: Tejedo Miguel
Published: March 2009

This study estimated variability in components of reproductive success in female natterjack toads (Bufo calamita, Laurenti, 1768) as a function of their body size and timing of reproduction. Two components of reproductive success were analysed: fecundity and metamorphic success. Fecundity, as a function of body size, tended to increase exponentially. Age had a negligible effect once body size was statistically controlled. Egg size was also related to female body size but showed greater variation. Metamorphic success depended on the timing of reproduction. Later breeders suffered an exponential decline in metamorphic success because females spawned at recently‐filled ponds of ephemeral duration. Since female body size decreased as the breeding season progressed, it may be inferred that larger, early‐breeding females would have a differential reproductive success. The inverse relationship between the timing of reproduction and body size may be based on the energetic physiology of vitellogenesis, and on the potential trade‐offs between the allocation of energy to growth—higher in smaller females—and reproduction.
Swarm behaviour and mate competition in mayflies (Ephemeroptera)
Authors: Harker Janet E.
Published: March 2009

Although mayfly swarms are frequently cited as an example of lekking by insects, little is known about the behaviour of individuals within a swarm, or how mate‐selection takes place. A study of five species of mayfly over a period of 10 consecutive years has revealed species‐specific differences in the flight pattern of swarming males and in the ability of males to recognize swarms of their own species. Males of four of the five species jostle other males in the swarm at all times except when mating: mating pairs are not jostled. The pattern of jostling varies with the species. Measurements of the sperm content of the vesicula seminalis and of the wing length of members of individual swarms show that larger wing size is positively correlated with the presence of less sperm. The vesicula seminalis is always filled with sperm at the beginning of the imaginal stage and the testes regress before the beginning of the imaginal stage. If the volume of sperm in the vesicula seminalis is a valid index of mating success then males with larger wings have the highest success. Large wings may bestow an advantage during jostling. The males of Ephemera danica, which do not jostle, glide with outspread wings; these outspread wings may attract females, the largest wings being the most attractive. Females of all five species enter the swarm a few at a time, although many females may be resting beneath the swarm. This phased entry may decrease the attraction of the swarm for predators. The number of females in a swarm is not correlated with swarm size, and the factors which enable females to regulate their entry into a swarm remain obscure.
Predator‐prey interactions between web‐invading jumping spiders and a web‐building spider, Holocnemus pluchei (Araneae, Pholcidae)
Authors: Jackson Robert R.
Published: March 2009

Three species of web‐invading salticid spiders, with different predatory strategies, were tested with Holocnemus pluchei in the laboratory: Portia fimbriata and Portia labiata, which practise aggressive mimicry, and Euyattus sp., which leaps from outside on to spiders in webs but does not practise aggressive mimicry. Portia was shown to be more efficient than Euryattus at catching H. pluchei. Portia fimbriata from Queensland was more consistent at using aggressive mimicry than was Portia labiata and was also more efficient at catching H. pluchei. The web‐invaders that were more efficient at catching H. pluchei were also better able to avoid setting off bouncing, a special defence behaviour used by H. pluchei. An experiment, in which H. pluchei was artificially induced to bounce whenever the predator was near, provided additional evidence that bouncing is effective in defending H. pluchei against web‐invaders.
Aerial photogrammetry of southern right whales, Eubalaena australis
Authors: Best P. B. , Rüther H.
Published: March 2009

Between July or August and November 1988 and 1989, 72 cow‐calf pairs of right whales (Eubalaena australis) were measured photogrammetrically from the air off De Hoop, South Africa. Median coefficients of variation ranged from 1.29 to 4.56%, being lowest in cows and calves for measurements of total length. Fifty‐seven adult cows measured from 12.37 to 15.54 m in length, with females photographed for the first time with a calf (= primiparous) being smaller than females that had been seen for the first time with a calf at least five years previously. The lengths of 72 calves ranged from 4.53 to 9.24 m, with those from primiparous females being significantly smaller than calves of multiparous females in every month except July. For 37 calves photographed on more than one occasion the growth rate averaged 2.8±0.7 cm per day, with no significant difference between growth rates of calves from primiparous and from other females, and no significant decrease in growth rate between July/September and September/November. Calves grew from an average of 40% of their mother's length in late July to 51% by mid‐October. The size distribution of the adult females was no different from that of 25 adult females landed at South African whaling stations between 1911 and 1963 (after adjustment for possible differences in measurement techniques). Five near‐term foetuses recovered in June‐August in the same whaling operations also agree closely with the size of calves predicted for 1 August. In a comparison with 17 calves stranded or dying accidentally on the South African coast, most of the accidentally caught animals agreed closely in size with the sample of photogrammetrically measured animals, while most of the stranded animals were equal to or smaller in size than the smallest length interval in the photogrammetrically measured animals. The calves of primiparous females may therefore suffer a higher natural mortality rate than those of multiparous females.
The behavioural and morphological affinities of some vanelline plovers (Vanellinae: Charadrüformes: Aves)
Authors: Ward David
Published: March 2009

The behavioural displays of six species of vanelline plover (Vanellus, Charadriidae, Charadriiformes) in southern Africa and Israel were recorded in the field. Using those displays considered to be systematically useful, I compared the relationships between species using behavioural and morphological characters. In general, the relationships between species using behaviour and morphology were congruent. The placement of the blackwinged plover Vanellus melanopterus and lesser blackwinged plover V. lugubris in a superspecies (Snow, 1978) was not supported by either behavioural or morphological data. The superspecific status of the blacksmith plover V. armatus and spurwinged plover V. spinosus proposed by Snow (1978) was supported by both data sets examined here. The morphological data examined indicate that the two South American species, the Chilean lapwing V. chilensis and Andean lapwing V. resplendens, are more closely related to one another than to any other lapwing species, and are probably derived from the Old World blacksmith/spurwinged plover superspecies.
Phenology of two territorial solitary bees, Anthidium manicatum and A. florentinum (Hymenoptera: Megachilidae)
Authors: Wirtz P. , Kopka S. , Schmoll G.
Published: March 2009

Five years' data on phenology of an Anthidium manicatum population in southern Germany and comparative observations on A. manicatum and A. florentinum from southern France are analysed. Males and females had the same flight season, adult sex ratio was strongly female biased and males were larger than females in both species. This is the opposite pattern to most other solitary bees, where females generally are larger than males, sex ratio is male‐biased, males emerge before females and males disappear long before females. We argue that two features of Anthidium female behaviour, namely prolonged sexual receptivity and use of resources easily defendable by males, explain male adaptations in behaviour, phenology and body size and, hence, population sex ratio.
Tool‐use by free‐ranging chimpanzees: the extent of diversity
Authors: McGrew W. C.
Published: March 2009

Most populations of free‐ranging chimpanzees (Pan troglodytes, Pongidae) across Africa use tools. This is equally true of wild and released populations and of all three geographical races. The few that do not use tools have yet to be thoroughly studied, but tool‐use seems species‐typical. No patterns of tool‐use are universal, although most function to facilitate subsistence. Even in preying on termites (Macrotermitinae, especially Macrotermes spp.) a variety of tools and techniques are shown, and many cross‐populational contrasts emerge. Regional differences exist, such as nut‐cracking with hammer‐and‐anvil being confined to the far western sub‐species. Continuing comparative study is needed.