bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass transfer efficiency between harp seal (Phoca groenlandica) mothers and their pups during lactation
Authors: Kovacs K. M. , Lavigne D. M. , Innes S. 
Published: March 2009

We investigated the efficiency of mass transfer in lactating harp seals through serial measurements on individual mother‐pup pairs during the whelping seasons of 1988 and 1989. We also compared the influence of longitudinal versus cross‐sectional sampling on estimates of the efficiency of mass transfer. Among longitudinally sampled pairs, pups grew at an average rate of 2·3 ± 0·5 (mean ± S.D.) kg/d (N = 20). The concomitant mass loss by females averaged 3·1 ± 0·8 kg/d (N = 19). The mean efficiency of mass transfer was 77·0 ± 13·6% (N= 19 pairs).Estimates of pup growth and female mass loss from regressions of cross‐sectional data were 2·0 kg/d and 3·1 kg/d, respectively. These values produce an estimate of 65% for the efficiency of mass transfer.Consistent with the high efficiency of mass transfer, harp seal females contribute less of their total body mass to nursing (c. 28%) than most other phocids examined. The resulting energy savings may be important for females of an ice‐breeding species, which migrate a long distance shortly after weaning their pups
Larvae of Maculinea rebeli, a large‐blue butterfly, and their Myrmica host ants: wild adoption and behaviour in ant‐nests
Authors: Elmes G. W. , Thomas J. A. , Wardlaw J. C. 
Published: March 2009

The behavioural interactions between caterpillars of Maculinea rebeli Hir. and their Myrmica ant hosts were studied, both in the wild at the time of adoption, and inside captive nests of six Myrmica species.In the wild, freshly moulted, final instar caterpillars left their food‐plants at a time of day that coincided with the peak foraging activity of Myrmica (18:00‐20:00 h). Once on the ground, caterpillars made no attempt to search for Myrmica but settled and waited for foraging ants to find them, which took up to 1.5 h. There was no adoption ritual: foragers of any Myrmica species picked up the caterpillars within 1–4 sec of discovery, and carried them directly to their nests.Caterpillars grew from < 2 mg to 110 mg in laboratory ant‐nests. About 60 mg was gained in autumn but 40% of this was lost during the winter, while the temperature was < 14 °C. Although caterpillars survived best with their normal host, Myrmica schencki, they could also survive in the nests of other Myrmica species. The presence of queen ants had no effect upon survival. The behaviour of the caterpillars was described and illustrated: this included the production of secretions that were drunk by the ants, begging for food and direct feeding by ants. The preferred solid food was ant eggs.The results are discussed in terms of the social biology of Myrmica ants. It is hypothesized that Maculinea rebeli caterpillars mimic the touch pheromones of ant worker‐larvae. This would explain the inability of ants to recognize caterpillars before touching them, their immediate adoption by any Myrmica species after discovery, host specificity inside wild ant‐nests, the absence of queen‐effect and the intimate attention of host workers.
Evaluation of a method for determining the length of sperm whales (Physeter catodon) from their vocalizations
Authors: Gordon Jonathan C. D. 
Published: March 2009

The click vocalizations of sperm whales often contain several regularly‐spaced, discrete pulses of sound. Norris & Harvey (1972) hypothesized that these were caused as a single pulse of sound produced at the front of the whale's head bounced between reflective air sacs at either end of the spermaceti organ. Thus the interval between pulses will be twice the travel time for sound along the length of the spermaceti organ. It should therefore be possible to determine spermaceti organ length and thence total body length by measuring the interval between these pulses. Several workers have used an equation relating inter‐pulse interval (IPI) to body length to estimate sperm whale body lengths acoustically.In this paper, aspects of this technique are examined in some detail. In particular, variability in IPIs and trends in IPI with time and depth are investigated. Most importantly, for the first time IPIs in the vocalizations of whales of known lengths have been measured.Variability in IPIs in the clicks of a single whale is acceptably low though there is a tendency for low and high values to occur in runs. There is no clear trend for IPI to alter significantly with the whale's depth or with the time since leaving the surface.IPIs are positively correlated with body length though not as predicted by the equations used by previous workers. Some likely errors in these equations are discussed. A new empirically derived relationship between IPI and body length has been calculated, though more data are desirable to obtain a more accurate and reliable equation.
The reproductive strategies of two Antarctic rotifers
Authors: Dartnall H. J. G. 
Published: March 2009

The bdelloid rotifers Philodina gregaria Murray and Adineta grandis Murray were both cultured through three generations. The results suggested the following models for calculation purposes: (1) that individual Adineta grandis live for 40 days and, at death, give rise to five offspring; (2) that individual Philodina gregaria live for 89 days, producing 18 young at three‐day intervals, the first on day 36 and the last on day 87 (the animal dying two days later).Mathematical expressions for population growth were formulated, from these models, and used to interpret the field observations obtained from a shallow pool on Signy Island (60°43′ S, 45°38′ W) during the course of an Antarctic summer.Midway through the summer, two seals crawled through the pool and upset the continuity of the field study. This natural catastrophe not only provided an interesting insight into the recovery of such habitats but provided an opportunity to test further the hypotheses formulated in the culture experiments.
Timing of births and juvenile mortality in the South American fur seal in Peru
Authors: Majluf Patricia 
Published: March 2009

In most species, synchronous, seasonal reproduction is usually associated with higher offspring survival in animals giving birth around the peak, relative to those breeding at the extremes of the reproductive season. In contrast, in the South American fur seal (Arctocephalus australis) at Punta San Juan, Peru, females pupping around the peak of births had a greater probability of losing their pups and/or tended to lose them at an earlier age than females breeding early or late in the season. However, the timing of breeding in this population varies little between years and is consistently synchronous. Individual females maintained their relative breeding times in consecutive years, regardless of whether or not they lost their pup the previous year. Thus, pup mortality seems to have no effect on the timing of reproduction in this population.High breeding densities and the consequent high pup mortality in the S. American fur seal in Peru may have resulted from intense poaching outside protected areas and are of recent origin. The reproductive synchrony in this population could have originally evolved as a response to seasonal variations in food availability and weather conditions, differences in female or pup body condition, predation pressure, sexual selection and/or harassment avoidance, but at the present high density levels has become maladaptive.
Different types of photophore in the oceanic squids Octopoteuthis and Taningia (Cephalopoda: Octopoteuthidae)
Authors: Herring P. J. , Dilly P. N. , Cope Celia 
Published: March 2009

The oceanic squid Octopoteuthis danue Joubin has one type of photophore on the head, body and arms, but another type on the eight arm tips. The first type has acomplexcapillary network, with elastic walls and a thick reflector. The arm tip organs have no such capillary core but a dense matrix containing paracrystalline assemblies. Taningia danae Joubin (the only other genus in the family Octopoteuthidae) has only two large arm tip photophores. These are similar in their general organization to the arm tip photophores of Octopoteuthis, but their detailed structure is quite different.There has evidently been independent evolution of photophores in this family of squids.
Cyathostoma lari (Nematoda) infection in birds of prey
Authors: Simpson V. R. , Harris Eileen A. 
Published: March 2009

Cyathostoma lari Blanchard, 1849 is a nematode which parasitizes the orbital and nasal cavities of gulls (Laridae), the crow family (Corvidae) and occasionally other species of birds. It has not, apparently, been reported in birds of prey, although two other species, C. americana and C. brodskii, have been recorded in the air sacs of raptors in North America and the USSR.This report describes infection by nematodes, provisionally identified as C. lari, in the orbital cavities of two kestrels (Falco unnunculus) and a common buzzard (Buteo buteo). A single specimen was also recorded in the lower eyelid of a sparrowhawk (Accipiter nisus). There was no evidence of pathogenicity in the kestrels and buzzard, but in the sparrowhawk the parasite was possibly associated with damage to the eyelid.
Activity patterns of pipistrelle bats (Pipistrellus pipistrellus) in Oxfordshire
Authors: Maier Celia 
Published: March 2009

A maternity colony of pipistrelle bats (Pipisfrellus pipistrellus), in Oxfordshire, was monitored between 1 March 1989 and 6 October 1989. An infra‐red ‘automatic bat counter’ was installed at the roost, to record the number of bats entering and leaving each minute throughout the night. Air temperature, light intensity at sunset, cloud cover, wind speed and rain were recorded on each night of monitoring. Insect abundance was estimated on 18 nights.The nightly activity pattern was found to be unimodal in pregnancy, bimodal during lactation and unimodal post‐weaning. The mean time that each bat spent outside the roost ranged from 103–483 min, with a mean of 321 min.Ambient air temperature and length of night were significant factors affecting mean time spent outside the roost. The percentage of the night which the bats spent away from the roost ranged from 22 to 88%, with a mean of 64%. There was a significant positive correlation between ambient air temperature and percentage of the night spent away from the roost. Insect abundance showed no significant correlation with the time that bats spent outside the roost. Wind and rain had no apparent effect on time spent outside the roost.
The structure of the mandibular corpus and its relationship to feeding behaviours in extant carnivorans
Authors: Biknevicius A. R. , Ruff C. B. 
Published: March 2009

Assuming some optimization of bone structure to applied mechanical loadings in vivo, different killing and feeding behaviours in carnivores should be reflected in observed differences in cross‐sectional shape of their mandibular corpora. Section moduli are used to gauge the magnitudes of bending moments in the mandibular corpus and, when dentary length is controlled, the magnitudes of forces applied to the corpus. Comparisons are made of section moduli at the P3P4 and P4M1 interdental gaps among canids, felids and hyaenids; in canids only, the M1M2 interdental gap was also studied. Local variations in loadings are identified by comparing the section moduli at adjacent loci along the corpus within each family.The findings of this study show that the precarnassial corpora of canids and hyaenids have greater strength in bending than the corpora of felids of similar body weight. This is taken to reflect relatively greater bending moments under loading in the corpora of canids and hyaenids due, in part, to their elongate dentaries (relative to body weight). Relative to dentary length, however, the precarnassial corpora of felids and hyaenids have much greater strength in bending than the corpora of canids. These scaling relationships appear to reflect the high customary forces (i.e. not moments) applied to the precarnassial corpora of felids and hyaenids with sustained canine killing bites and with bone ingestion using the premolars, respectively. An increase in bending strength of the corpus caudal to the camassial blade in canids is interpreted to be an adaptation for bone‐crushing with the postcarnassial molars.
Egg size, first instar behaviour and the ecology of Lepidoptera
Authors: Reavey Duncan 
Published: March 2009

There is striking variation in egg size among Lepidoptera. Part of the explanation could be a link between egg size and larval feeding ecology.The relationship between absolute egg size and aspects of feeding ecology for different Lepidoptera families from different temperate regions is examined. Species that overwinter in the egg stage have larger eggs. There are significant differences in egg size with respect to feeding specificity but different families show different patterns. Woody plant feeders have larger eggs than herb feeders. There is little effect of proximity of the egg to the plant part that is eaten.Patterns in the behaviour and survival of newly hatched larvae of 42 spp. of British Lepidoptera and their relationship to egg and larval size and to food plant characteristics are examined. Patterns in egg size with respect to feeding ecology are similar to those described above. There is a strong correlation between egg size and the size of newly hatched larvae. Newly hatched larvae survived for a mean of 1–20 days without food. Survival is not correlated with larval weight. Grass feeders survive longer than herb and woody plant feeders; the species surviving the longest feeds on lichens. Newly hatched larvae moved at a mean speed of 0.7‐267.8 cm h‐1. Speed is not correlated with larval weight or survival time. Grass feeders move faster than woody plant feeders which, in turn, move faster than herb feeders. Woody plant feeders tend to move upwards, grass feeders downwards and herb feeders both upwards and downwards. The proportion of larvae silking is negatively correlated with larval weight.The strong links between egg size and larval feeding ecology and between feeding ecology and larval behaviour are discussed. It is surprising that larval body size does not appear to constrain the speed of movement, nor tolerance to starvation.
Utilization, diet and diet selection by brent geese Branta bernicla bernicla on salt‐marshes in Norfolk
Authors: Summers Ron W. , Stansfield Julia , Perry Sue , Atkins Clare , Bishop Julie 
Published: March 2009

The diet and utilization by brent geese of two plant communities (Limonium/Armeria marsh—a short sward community in the upper mid salt‐marsh and composed of several species, and Salicornia marsh—a community of the lower salt‐marsh dominated by Salicornia europuea agg. and Aster tripolium) were studied on the north Norfolk coast. The biomass on these communities was highest in autumn and declined markedly in November owing to the senescence and die‐off of the succulent species. This decline was not significantly precipitated by the grazing of the geese but coincided with their switch to inland habitats where the biomass m‐2 and total food available on fields of winter wheat and grassland within the population's home range was 20–30 times greater. Brent geese continued to graze salt‐marsh at a low intensity through the winter, feeding largely on Puccinellia maritima. In spring they returned largely to Limonium/Armeria marsh where they significantly reduced the regrowth of Puccinellia maritima.The main plant species ealen was Puccinellia maritima, especially in mid winter. Salicornia maritima agg. leaves and seeds formed much of the diet in autumn, whereas Triglochin maritima, Plantago maritima and Aster tripolium were important foods on Limonium/Armeria marsh in spring. All these species were selected at some part of the year. Selection was related to the proline (an imino acid used by salt‐marsh plants as an osmoregulator) and chloride content and avoidance related to tannins. Two species which contained condensed tannins. Limonium vulgare and Armeria maritima, were rarely eaten. As well as being a nutrient, proline may help to neutralize the effects of tannins in the diet if incorporated into proline‐rich proteins.
The relative merits of foregut and hindgut fermentation
Authors: Alexander R. McN. 
Published: March 2009

Mammalian herbivores cannot break down cellulose except by fermentation, and may have Termentation chambers at either end of the gut: ruminants have their principal fermentation chamber in the stomach but horses ferment only in the hindgut. A mathematical model (Alexander, 1991) predicted that foregut fermenters should do better than hindgut fermenters on poor foods, and the reverse on richer. less fibrous foods. Further, the optimum gut for poor foods would have the hindgut fermentation chamber only a little smaller than the foregut chamber. However. it has been claimed that horses do better than ruminants on poor food, and the hindgut of ruminants is much smaller than the rumen.In this paper, the basic model is modified in ways designed to make it more realistic and the effects are investigated. None of the modifications alters the conclusion that the optimum gut for poor food has a large foregut fermentation chamber. However, the optimum proportions of fore‐to hindgut, for poor diets, become more like those of real ruminants when account is taken of the diminishing volume of the food passing through the gut, and of incomplete mixing in the rumen.
The diet of the introduced carnivorous snail Euglandina rosea in Mauritius and its implications for threatened island gastropod faunas
Authors: Griffiths O. , Cook A. , Wells Susan M. 
Published: March 2009

Euglandina was collected over a three‐year period in four habitat types in Mauritius. Smaller collections were also made in Reunion and Rodrigues. The areas in which the Euglandina were collected were simultaneously sampled for potential prey species. Identification of the stomach contents and comparison with the available prey shows that most prey are eaten whole and that native species are eaten in greater numbers that would be expected form a consideration of their numbers in the habital. Achatina spp., which Euglandina was originally introduced to control, was not positively identified in the diet. Even if all unidentified prey fragments were form Achatina then this would form less than 5% of the total number of items in the stomachs.Habital destruction, together with predation by Euglandina, appear to be major contributors to the extinctions of native Mauritian snails. The conservation of primary forests, into which Euglandina has not penetratd, is suggested as the most effective way to save the remaining endemic ground‐dwelling snails form extinction. These results add further emphasis to the importance of preventing introductions of Euglandina to areas with native snail faunas, and show clearly that this predator is not a successful control agent for Achatina.
Intraspecific variation in resistance to desiccation and climatic gradients in the distribution of the bush‐dwelling land snail Trochoidea simulata
Authors: Arad Z. , Goldenberg S. , Heller J. 
Published: March 2009

Resistance to desiccation was examined in six populations of the Israeli bush‐dwelling snail Trochoidea simulata, a desert species distributed mainly between the 100–200 mm isohyets.The present study revealed significant intraspecific differences in resistance to desiccation which are correlated with habitat and climatic gradients within the distribution range of the species. Populations from more arid sites were more resistant to desiccation and heat exposure than those from more mesic areas. However, the population from the Rift Valley (an extremely arid region) was surprisingly poorly resistant. Rates of population water loss under the controlled experimental conditions in the laboratory generally matched the calculated water losses during natural summer aestivation.
The dorsal paracloacal gland and its relationship with seasonal changes in cutaneous scent gland morphology and plasma androgen in the marsupial sugar glider (Petaurus breviceps; Marsupialia: Petauridae)
Authors: Bradley A. J. , Stoddart D. M. 
Published: March 2009

A study spanning two breeding seasons was carried out to examine changes in the size of the dorsal paracloacal glands and testes in the marsupial sugar glider Petaurus breviceps Waterhouse 1839. These changes were related to seasonal increases in the plasma testosterone concentration and to morphological changes in the frontal and gular cutaneous scent glands of males.Both dorsal paracloacal glands and testes underwent a seasonal cycle of development which reached its maximum during the June‐September breeding season. These changes coincided with an increase in the plasma testosterone concentration and with the increase in activity of certain cell types within the frontal and gular glands.Castration caused a significant decrease in the size of the dorsal paracloacal glands, while androgen replacement was effective in restoring the glands to their pre‐castration size thus demonstrating the influence of androgens upon the activity of these glands.The synchronization which exists between plasma testosterone concentration, cutaneous scent gland morphology and the size of the dorsal paracloacal glands of males, suggests that the dorsal paracloacal glands, or more likely their secretions, are important in social organization in this species.
A comparative study of the ecology of woodmice Apodemus sylvaticus in two contrasting habitats: deciduous woodland and maritime sand‐dunes
Authors: Gorman Martyn L. , Akbarbin Zubaid , Ahmad Mukhtar 
Published: March 2009

The woodmouse is a characteristic rodent of deciduous woodland but also occurs in a wide variety of othe habitats. This paper describes the comparative ecology of woodmice living in two habitats of markedly different productivity; deciduous woodland and a maritime sand‐dune system.The diets of the two populations were quite different; woodland mice ate mainly seeds whilst those on the dunes subsisted on invertebrates, particularly Coleoptera.Population densities in the woodland were higher than those on the dunes. In contrast, home range sizes were much larger on the dunes.Mice living in the two habitats exhibited different patterns of activity. The dune animals left their nests earlier in the evening and they were active for longer each night.It is argued that all of these differences between the two populations are due to differences in food availability in the two habitats.
Aggregation in the tropical millipedeAlloporus uncinatus(Diplopoda: Spirostreptidae)
Authors: Dangerfield J. M. , Telford S. R. 
Published: March 2009

Millipedes tend to have a near random dispersion pattern when surface active. Only in a few species do juvenile stadia form dense swarms. This study describes the occurrence and composition of aggregations in an adult population of the tropical spirostreptid millipedeAlloporus uncinatus(Attems) inhabiting riparian forest in Zimbabwe. Also presented are the results of a field experiment designed to induce aggregation behaviour in a separate population with the addition of high quality food to the habitat.Our initial hypothesis that the natural aggregations of between six and 42 individuals observed during the period of surface activity were part of the mating system in this species was refuted. Few mature males were present in aggregates and less than 1%, of copula pairs sampled were taken from aggregates. The composition of aggregates and the results of the experiment suggest that aggregations are associated with the feeding activities of immature individuals and are not related to reproductive activity. We suggest that the aggregations observed inA. uncinatus, although related, may perform different functions to the swarming behaviours observed in other millipede species.