摘要:

In a study to examine the effect of climate on life cycles, a total of 408Carabus problematicuswere caught in pitfall traps at four altitude sites between 660 m and 1055 m on Snowdon, north Wales. Under the assumption that the mandible condition of these beetles was related to the age of the individuals, an objective estimate, which was both sex‐ and size‐independent, was used to separate the captures into two age categories. The results from this estimation process suggested that beetles from the different altitudes followed different life strategies; low altitude beetles being predominantly annual and high altitude beetles predominantly bienn

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01779.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

We studied the behaviour of grey seals,Halichoerus grypus, during the breeding period at Froan, Norway, and compared our findings with existing studies on grey seals at breeding sites in Britain and Canada. The pups at Froan spent more time in water than pups at other breeding sites. While on‐shore, the pups at Froan spent most of their time resting, behaviour similar to pups at other breeding sites. Lactating females at Froan spent most of their time in the sea, thus differing from females at most other breeding sites which spend most of their time on‐shore. While in the sea, the females at Froan spent most time diving, typically interrupted by regular periods of surface swimm

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01780.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Laboratory experiments were carried out to assess the tolerance and behaviour of the southern African spirostreptid millipedeAlloporus uncinates(Attems) to moisture and temperature stress. Rates of water loss in dry air were 0–026 mg H20 cm‐2hour‐1for females and 0021 for males and remained relatively constant with an increase in temperature from 20 to 30°C but at higher temperatures there was a rapid increase in water loss, especially for females. In dry laboratory conditions at 30°C all individuals died within 30 days, whilst at 20°C at least 90% of individuals survived this period. Aggregation appeared to have no significant effect on survivorship but small body size conferred a survivorship advantage. Females burrowed earlier and to a greater depth than males, and initial moisture content of soil had a significant effect on mean burrow depth.Alloporus uncinatus, like other spirostreptid millipedes, appears to have considerable tolerance to dry conditions but the wide geographic and habitat range of this species may mean that the intensity of selection for tolerance to moisture stress

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01781.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The shoulder heights of 224 females and 170 males, and hindfoot length of 236 female and 217 male known‐age African elephants (Loxodonta africana) were measured, and growth curves constructed for each measure of size. A linear relationship between foot length and shoulder height was confirmed in simultaneous measures of 97 males and 110 females. Growth curves demonstrated the typical sexual dimorphism in both foot length and shoulder height, with males growing more rapidly than females from birth onwards. The size dimorphism in foot length and shoulder height becomes marked by the age of 10 years, with males on average being 60–70 cm taller than females at 65 years. This size dimorphism is produced through faster growth which continues for longer than does that of females. The variance in growth rates is slightly greater for females than for males. It is proposed that female growth after puberty is affected by a trade‐off between growth and reproduction, while males who deviate markedly from typical patterns of growth may be subject either to mortality or energetic constraints limiting their potential var

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01782.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The activity of radiotagged adult crested porcupinesHystrix cristataL., 1758, was studied in a rural hilly area of Central Italy, from July 1990 to June 1991. Three males and one female were monitored every 15 minutes for 18–24 hours/individual/week, and their activity patterns were correlated to ambient temperature, precipitation and lunar phases. Three individuals, out of the four monitored, showed a fall of activity in the beginning of the cold season, but generally porcupines appeared adapted to a wide spectrum of temperatures. The mean duration of nocturnal and crepuscular activity was 9 h 22'±42', showing little variation throughout the year. In the cold months, i.e. when nights are relatively longer, porcupines usually left their burrows after sunset and came back some hours before sunrise. In the warm season they left their burrows at sunset, or shortly before, and returned at sunrise, or shortly after. Overall diurnal activity was scarce (2 h 11' ± 1 h 30'), but in spring it increased to over 40% of the diel activity (3 h 22' ± 3 h). Moonlight avoidance was slight. Precipitation did not seem to influence the activity of porcup

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01783.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

Our aim was to describe the free‐ranging diving pattern and to determine the location of foraging of pregnant female southern elephant seals,Mirounga leonina, from Peninsula Valdes, Argentina. This colony is unusual in two respects: it is removed from deep water by a broad shallow shelf (345–630 km wide), and colony numbers have been increasing in recent years in contrast to numbers from other southern hemisphere colonies that are stable or in decline. Microprocessor controlled, geolocation‐time‐depth recorders were deployed on four females, recording a total of 15,836 dives (270 dive days) during the period February to April, 1992. Departing seals crossed the continental shelf quickly (54–5–62–1 h) and did not show signs of foraging until reaching deep water, due east of the colony in the South Atlantic Ocean. Diving was virtually continuous (93% of the time underwater) with overall mean (±S.D.) rates of 2.5±0.2 dives/h, mean dive durations of 22.8 ± 7.1 min (maximum dive duration = 79 min) with 1.6±0.6min surface intervals between dives, and dive depths of 431±193m (maximum dive depth = 1,072 m). The diving pattern of females from Patagonia is similar to that of seals from colonies where numbers are decreasing (Macquarie stock) or are stable (South Georgia Island). Our subjects did not, however, feed in or south of the Antarctic Polar Front, or in cold waters along the Antarctic coast, where seals from declining or stab

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01784.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

A nomenclature for the teeth of the radula of fossil and living Cephalopoda is proposed. The names suggested can be used for the 13 elements (teeth and plates) across each transverse row of the radula of Nautiloidea (fossil and extant), and, by retaining the names for all except the two outer elements on either side, for the nine elements in Ammonoidea (fossil) and Coleoidea (fossil and extant). One transverse row of the radula has a central rhachidian tooth, and on either side lateral tooth 1, lateral tooth 2, marginal tooth 1, marginal plate 1, marginal tooth 2, marginal plate 2, the last two being present only in the Nautiloidea.

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01785.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

We hypothesized that the presence of the forked hemipenes, and associated musculature, at the base of the tail in male lizards should constrain the capacity to autotomize the tail. Thus, this hypothesis predicts that the non‐autotomous base of the tail should be longer in male than in female lizards. We tested this hypothesis in four species oflacertid lizards. Males have on average one to two non‐autotomous vertebrae more than females, and the sexual difference in length of the non‐autotomous tail base remains constant over the entire body size range. In addition, the first functional autotomy plane in males is usually located on, or is distal to, the vertebrae from which two hemipenial muscles take origin. These observations support the view that functional demands of the male intromittent organs impose constraints on the abilities of tail autotomy. In a natural population ofLacerta vivipara, the proportion of tail breaks that occurred at very short distances from the base was highest in females, indicating that the small sexual difference in length of the non‐autotomous tail part is of functional significance. Total length of the tail was largest in males. This can be interpreted as a compensation for the decline in autotomy capacities at the tail base, such that the length of the autotomous part remains similar in bot

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01786.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

The threat behaviour inVaranus griseuswas investigated with high‐speed cinematography and X‐ray films. Lizards exhibit threat display involving throat movements and associated throat, thorax and mouth movements. The functional anatomy of the bucco‐pharyngeal region is described and threat displays are kinematically studied and functionally interp

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01787.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

J.‐M. WEBERThe influence of food abundance on red fox feeding habits was studied in the Swiss Jura Mountains between November 1990 and February 1992, during a low density period in the water vole population cycle. Six food categories–water voles, small mammals, domestic stock, earthworms, wild fruits and exploitable scraps–were censused during the present research and their seasonal abundances were estimated in fixed plots. Fox scats were collected and analysed at regular monthly intervals.The diet of foxes was found to be correlated with seasonal food supply. A positive significant correlation between seasonal abundances and relative proportions in the diet was found for food categories showing a clear seasonality (earthworms, wild fruits and exploitable scraps), whereas no correlation was recorded for the other food resources. Diet composition observed in the present study was compared with that recorded in the same study area between 1988 and 1990 by Weber&Aubry (1993), when water voles were very common and accounted for more than 50% of the diet. A significant change was recorded in red fox feeding habits: the most important aspects of this modification of the diet was the decrease in water vole importance accompanied by the increase in the frequency of occurrence of other food categories, such as wild fruits and scavengeable

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1995.tb01788.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY