摘要:

A method for representing individual growth rates of aquatic insects from field sampling is presented using the mean instar number as the age criterion. Various examples are used to show how the method is useful in making both intra— and interspecific comparisons. Significantly different growth rates are shown between populations of the same species in different habitats. Also, an example is presented which shows the possible role of temporal separation in niche differentiation between two similar species.

ISSN:0012-9658    

DOI:10.2307/1933673

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

摘要:

The relationship between captive red squirrels (Tamiasciurus hudsonicus) and grey squirrels (Sciurus carolinensis) was studied by comparing the behavior or mixed pairs and conspecific pairs in a large outdoor cage containing one primary nest box above ground and another exposed on the ground surface. While red squirrels always shared the nest box with conspecifics, grey squirrels never did so. When both species were present, the grey squirrels occupied the nest box, but shared it 37% of the time with the red squirrels. No fighting or wounds were observed. The much publicized aggressiveness of the red squirrel toward the grey may be a function of territorial behavior in certain parts of its range (conifer forest) rather than an inherent characteristic of the species.

ISSN:0012-9658    

DOI:10.2307/1933674

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

摘要:

After 15 yr tagging at the nesting ground of Chelonia mydas at Tortuguero, Costa Rica, 447 remigration returns have been recorded. These confirm previous indications that some Tortuguero females return to nest every 2 yr and some every 3 yr, with the latter being the more frequent cycle. Returns after absences of 4 yr are so frequent that it seems probable that a regular cycle of this magnitude also exists. Longer absences recorded (up to 9 yr) probably can be attributed to missed encounters or to weak site tenacity by the returning turtles. A growing list of two—time and three—time returns shows that although an individual usually maintains a constant cycle, modulation of this may occur, and that the change may be either from 3 to 2 yr, or vice versa. It is suggested that the modulation reflects ecological conditions on the feeding ground. A sudden extensive shift to a 2—yr cycle, by turtles that had been nesting on a 3—yr cycle, probably contributed to the heavy nesting that occurred in 1969, after several previous weak seasons.

ISSN:0012-9658    

DOI:10.2307/1933675

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

摘要:

Resource partitioning was studied in 20 species of the water mite genus Eylais, the larvae of which parasitize adult Coleoptera and Hemiptera living in shallow ponds. Co—existence of sympatric species is possible because the mites exploit host resources in different ways. Most commonly they parasitize different species, but when hosts are identical, the mites remain segregated by differences in the precise site of attachment, biotope, or season of parasitism. Mite biology, host dispersal, and competition for attachment sites from other water mite species may restrict further subdivision of host resources.

ISSN:0012-9658    

DOI:10.2307/1933676

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

摘要:

In the light of current opinion that habitat selection by birds is determined largely by gross visual aspects of the vegetational physiognomy (Hilden 1965), one might intuitively expect that drastic alteration of the ground and shrub strata of a forest would modify the composition and numerical status of resident bird populations. However, counts in a burned pine stand in southern Florida during the first few months after burning were essentially no different than counts in an immediately adjacent unburned stand. The lack of response to this habitat alteration may be attributed behaviorally to individual home range attachments by the resident birds. Its occurrence in this situation may be associated with the relatively brief during of these habitat disruptions and the frequency of forest fires as a normal feature of slash pine ecology.

ISSN:0012-9658    

DOI:10.2307/1933677

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

摘要:

Tests (by enrichment culture) for nonsulfur purple photosynthetic bacteria in surface soils showed them in all of three sediment cores sampled in a shallow pond and in all of six peats from nearby swamp hollows beneath cedar and tamarack. They also occurred in two of three peats from swamp flats and three of five peats from swamp hummocks. For woodland and grassland surface soils, proportions were three out of seven and five out of nine sites respectively. For the total number of tubes inoculated at varying dilutions from each of these sites, the following proportions of positives were recorded: uppermost lake sediments 92%, swamp hollows 67%, swamp flats 38%, swamp hummocks 20%, woodlands 14%, grasslands 8%.

ISSN:0012-9658    

DOI:10.2307/1933678

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

摘要:

An inexpensive, portable, electronic metronome emits tone pulses through an earphone at intervals which can be varied from 1 to 20 sec, and may be used in a variety of ways to provide a time base for studies in behavioral ecology. Several suggestions for the conduct of field studies in behavioral ecology are made.

ISSN:0012-9658    

DOI:10.2307/1933679

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

ISSN:0012-9658    

DOI:10.2307/1933680

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

ISSN:0012-9658    

DOI:10.2307/1933681

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY

ISSN:0012-9658    

DOI:10.2307/1933683

出版商:Ecological Society of America    

年代:1970

数据来源: WILEY