摘要:

Observations were made of a wild population of sugar gliders (Petaurus breviceps) by live‐trapping and on four captive colonies to establish the relationship between blood concentration of testosterone, body weight, social dominance and the timing of births. In both the wild and in captivity one male exhibits a testosterone concentration far higher than his fellows, during the breeding season. This male is also the heaviest. In captivity this male is observed to be socially the most dominant and undertakes almost all of the scent‐marking. At least three‐quarters of each breeding season's births occur during the first month of the three‐ to four‐month season (July‐September/October), a passage of time during which the body weight of the most dominant male falls more than that of the subordinates. It is suggested that this species is highly polygynous, with the ecological and evolutionary benefits of high social status be

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04615.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Adipose tissue was dissected completely from 25 adult male and five adult female wolverines shot between October and March, 1990–1992 in Northwest Territories, Canada. The gross mass, mean adipocyte volume, lipid, protein and collagen contents were measured in adipose tissue from 13 superficial and internal depots homologous to those of other terrestrial mammals. The total adipocyte complement was calculated from the mass of each depot and its site‐specific adipocyte volume. Almost all the adipose depots found in other terrestrial mammals were present in wolverines and site‐specific differences in adipocyte volume were similar to those of other species. No significant sex differences were detected. All depots except the cardiac adipose tissue enlarged with increasing fatness, but the superficial depots expanded faster than any of the internal depots and the posterior superficial depots enlarged slightly faster than the anterior depots. The partitioning of adipose tissue between superficial and intra‐abdominal depots, and between anterior and posterior superficial depots, changed with fatness and was consistent with predictions from allometric equations derived from data from other Carnivora. The total adipocyte complement was variable, with more than 70% of the specimens having 2–5 times as many adipocytes as predicted from allometric equations relating adipocyte complement to body mass in other carnivorous mammals. Consequently, the correlation between mean adipocyte volume and total dissectible adipose tissue was weak. Measurements of adipocyte volume from biopsies of adipose tissue, and indices based upon the mass of thickness of one or a few depots, would therefore not provide an accurate estimate of fatness. The concentration of collagen was higher in the superficial and intra‐abdominal adipose depots of specimens collected in mid‐winter than in homologous tissues of those killed in early winter, but there were no comparable seasonal changes in the abundance of lipid or non‐c

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04616.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The origin(s), distribution and fate(s) of exosomatic water in the semi‐terrestrial amphipod,Orchestia gammarellus(Pallas 1766) have been investigated. These observations were coupled with a study of the gross morphology of the ventral groove and associated structures and a physiological investigation of gill function, allowing an appraisal of the metabolic significance of exosomatic water. The key to the success of amphipods invading land lies, we suggest, in the retention of exosomatic water by capillary action within a water‐conducting system (analogous to that found in isopods) located within the ventral groove. This exosomatic water allows ‘aquatic’ methods of gas, water and ion exchange to continue unimpeded as long as the ventral groove can be recharged either from urine or standin

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04617.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The Ratites (ostriches, emus, etc.) are thought to be neotenous descendants of flying birds, rather than primitive birds, even though they became a separate group early in the evolution of birds. This is because of the juvenile, rather than primitive, condition of the palate, skull‐sutures and feathers. We report here that European starlings(Sturnus vulgaris)thyroidectomized soon after hatching also show neoteny, retaining many juvenile features (general morphology, palate, skull‐sutures, feathers, behaviour), while at the same time becoming sexually mature. The juvenile characters were similar to those found in Ratites, suggesting that hypothyroidism may have been a factor in the evolution of the Rati

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04618.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The total suckling time and the fawns’ absolute increase in weight from birth to weaning were studied in a group of fallow deer over two consecutive calving seasons. The aim was to clarify the use of suckling time as a predictor of parental input in fallow deer. When all subjects from both years are taken into account, no positive relation between suckling time and growth was found. This was due to at least two important factors: (i) fawns to primiparous mothers sucked relatively longer, with no corresponding increase in weight, compared to multiparous mothers; and (ii) suckling time during the first two weeks after birth seems to be an inadequate measure of milk transfe

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04619.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The skull morphology and function of the anomodont mammal‐like reptileVenjukoviais described and compared with that ofPatranomodon, Eodicynodon, GaleopsandDiictodon.Changes in osteology and functional anatomy of these forms are noted.It is concluded that the acquisition of herbivorous adaptations in the anomodonts may have occurred in the following sequence: division of the external adductor muscles of the jaw into a medial and lateral component, propalinal jaw movement, increased Moment Arm of the external adductors by raising the level of the jaw hinge, anterior migration of the adductor insertions, reduction of the size and number of teeth and acquisition of a horn covering to the jaws, elaboration of the external adductors and reduction of the internal adductors (pterygoideus muscles), and elaboration of palatal areas for mastication of food.The first (in the morphological sense) committed herbivorous anomodont is identified as the South African form,Galeops.As far as anomodonts are concerned, the major correlate of successful herbivorous feeding is the acquisition of propaliny.A chronology of character acquisition in the anomodonts cannot yet be drawn up since the stratigraphic correlation of Russian and South African sequences is uncertain. However, it appears that the transition from a generalized carnivore to a committed herbivore took place very rapidly compared to the species longevity of anomodont

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04620.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

We investigated the geographic variation of eight Ethiopian populations of the rodentLophuromys flavopunctatusand compared them to the Bale endemic speciesL. melanonyx.We used multivariate morphometrics and analysed independently skull and external body linear measurements, in an attempt to relate morphological variability to geography (latitude, longitude, altitude). There is a high morphological diversity in these Ethiopian populations, which form three distinct recognizable groups, with the Bale population being the most distinct. The results of analyses on the two character sets corroborate each other and indicate that the kind of variation is not ‘ecological’ but rather there is a phylogenetic cause, and relations at higher taxonomic level are suggested. There is a homogeneous group with five populations within which there is a recognizable pattern of clinal variation related to altitude, with a decrease in body size and a change in skull sh

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04621.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

We report observations of allomaternal care, or epimeletic (care‐giving) behaviour, exhibited by one female toward another, before, during, and after giving birth, in the Rodrigues fruit bat,Pteropus rodricensis(Chiroptera: Pteropodidae). Interactions between the expectant mother and other roost mates, from the onset to completion of birth, were observed continuously over a period of approximately three hours. The attending female assisted the mother when she: (I) intermittently groomed her anovaginal region; (2) grasped her with partially outstretched wings; (3) ‘tutored’ her in a feet‐down birthing posture; (4) groomed the emerging pup; and (5) physically assisted the mother by manoeuvring the pup into a suckling position. This is the first report of extensive assistance given by a female bat to another during parturition. We suggest that epimeletic behaviour may be common in the highly social Chiroptera, especially among primiparous or inexperienced females and/or when an expectant mother experiences difficulty during labour and parturition. Our observations support the hypothesis that roosting associations in bats may be as important as relatedness in explaining the occurrence of apparently altruist

ISSN:0952-8369    

DOI:10.1111/j.1469-7998.1994.tb04622.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY