摘要:

The results of a comparative study of a trophic spectre of three species of shorebirds(Tringaflavipes. CalidrisfuscicollisandCharadrius collaris), are given in this contribution. They show the mechanisms of isolation despite sharing the same source of food. Considering the diversity of food, the mechanisms of isolation can be shown in the trophic as well as in special dimension of the ecological niche. Specialization on certain types of food and different types of habitat use are the prevalent strategies to avoid competitive exclusion.

ISSN:0165-0521    

DOI:10.1080/01650529109360836

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

SCHULTES, R.E. & R.F. RAFFAUF (1990): The Healing Forest. Medicinal and Toxic Plants in the Northwest Amazonia. Dioscorides Press, Portland, Oregon, USA. 500 pp, 136 b/w photographs, hardbound. $59.95 plus $3.00 for shipping and handling.

ISSN:0165-0521    

DOI:10.1080/01650529109360842

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

This paper completes the study of the life cycle ofSteatoda retorta, which was published before (González, 1987). The dates given in this paper were obtained from specimens reared in laboratory. Variations of mortality, survivorship and mean life expectation were studied. The survivorship curve indicates that the experimental population was affected by mortality since age 4 to 9 being this a critical period because the nymphs moult from I to II and from II to III instars. The curve shows another critical period when the population moults to adult stage. The mean life time of the cohort was 37.09 weeks. These results were compared with the data recorded forL. mirabilis, L. antheratus, L. corallinus, L. diaguitaandTidarren sisyphiodes. This analysis showed differences as: a) The survivorship curve ofSteatoda retortais more convex than the others because there is no differential mortality between males and females, b) The higher value of the mean life expectation inSteatoda retortaoccurs when the first critical period finished (II, III instars). In the species ofLatrodectusandTidarren sisyphoidesthis occurs when the populations are at adult stage, c) The value of the mean life time of the cohort and the life cycle is higher inSteatoda retortathan in the other species.

ISSN:0165-0521    

DOI:10.1080/01650529109360837

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Lavellodrilus ilkusandL. bonampakensisare described from two Mexican tropical rain forests. Some ecological observations are also discussed. Despite the presence of an intestinal gizzard, these species are placed in the genusLavellodrilus(where this character is absent) because they present sexual characters diagnostic of this genus and by the close association of this feature with a certain ecological niche. The adaptive nature of intestinal gizzards in non‐moniligastid genera is discussed in terms of: their repeated appearence, Bouche's hypothesis of functional constraints and the suggested adaptive function. It is proposed that in the new species described seasonality of tropical rain forest environment may have represented the constraint which selected the displacement of the gizzard.

ISSN:0165-0521    

DOI:10.1080/01650529109360838

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Six species and subspecies ofBulimulusare represented in the Republic of Argentina:B. apodemetes, B. bonariensis bonariensis, B. bonariensis sporadicus, B. prosopidis, B. rushiiandB. vesicalis vesicalis. Their variations and geographic distribution are discussed, their spermatophores described.B. sporadicus gracilis, B. jorgenseniandB. jujuvensisare species which do not belong to the genus.

ISSN:0165-0521    

DOI:10.1080/01650529109360839

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A study of the 24‐hour cycle of activity in Capybaras in the llanos of Venezuela was made using visible red light for nocturnal activity. Observations were made during both the dry and rainy season. In both cases Capybaras showed 4 peaks of activity during the 24‐hour cycle, but in the dry season 3 peaks were after dark while in the wet season 2 peaks were by day and 2 by night. By night groups of Capybaras moved rapidly to grazing sites keeping together by low volume vocal communication. Experimentation showed that visible red light permits close approach to Capybaras because it hides the observer. Coprophagy was frequently observed, almost exclusively during the morning resting period. Copulations were observed mostly in May (dry season), all but one in water, and most between 08.00 to 13.00. It is suggested that censuses for establishing harvest quotas avoid resting periods because important proportions of Capybaras may be hidden in thickets or aquatic vegetation.

ISSN:0165-0521    

DOI:10.1080/01650529109360840

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A recent review lists all forms ofEuneomysas a single species. We show in this report that two species live sympatrically at two localities in Chile and two in Argentina. The grooves on the anterior surfaces of the upper incisors are centrally positioned in one of the species and laterally positioned in the other. The species with central grooves has a larger head and body, larger hind foot, wider interorbital constriction, wider rostrum, longer molar toothrow, larger claws on the front feet, and lives in deep soils. The smaller species lives in bare, rocky habitat. The genusEuneomysthus comprises at least two species. The namesmordaxandchinchilloidesare appropriate for the large and the small species, respectively.

ISSN:0165-0521    

DOI:10.1080/01650529109360841

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:0165-0521    

DOI:10.1080/01650529109360835

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor