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121.
122.
123.
Dagmar I. Werner Esmeralda M. Baker Elizabeth del C. Gonzalez Ines R. Sosa 《Behavioral ecology and sociobiology》1987,21(2):83-89
Summary The research addressed two questions: (1) doIguana iguana hatchlings recognize their kin, and (2) what are the recognition mechanisms? Eggs were collected from wild and captive-raised
females and hatched in semi-natural incubators. In the first experiment we used eggs from two females. One of the clutches
was subdivided to be placed in different incubators. Immediately after emergence one of these hatchling groups was introduced
into a 10 m x 10 m enclosure. At the same time we introduced hatchlings from another female. The remaining hatchling group
was kept separate for 3 weeks and was then introduced into the same cage. Unrelated hatchlings separated from each other.
Related but separated hatchlings grouped according to introduction date. In the second experiment we maintained eight kin
groups in individual cages and two hatchlings per kin group in an additonal cage. Hatchlings from the mixed group showed no
preference for their kin before physical contact with pure kin groups had occurred. After physical contact hatchling recognized
their kin by feces smell. Body odor is likely to be also involved. 相似文献
124.
Spread of metals through an invertebrate food chain as influenced by a plant that hyperaccumulates nickel 总被引:6,自引:0,他引:6
Lynsey R. Peterson Victoria Trivett Alan J.M. Baker Carlos Aguiar A. Joseph Pollard 《Chemoecology》2003,13(2):103-108
Summary. Hyperaccumulation of metals in the shoot system of
plants is uncommon, yet taxonomically and geographically widespread. It
may have a variety of functions, including defense against herbivores.
This study investigated the effects of hyperaccumulation on metal
concentrations across trophic levels. We collected plant material, soil,
and invertebrates from Portuguese serpentine outcrops whose vegetation
is dominated by the nickel hyperaccumulator Alyssum pintodasilvae.
Samples were analyzed for nickel, chromium, and cobalt. Grasshoppers,
spiders, and other invertebrates collected from sites where A.
pintodasilvae was common had significantly elevated concentrations of
nickel, compared to nearby sites where this hyperaccumulator was not
found. Chromium and cobalt, occurring in high concentrations in the
serpentine soil but not accumulated by A. pintodasilvae, were not
elevated in the invertebrates. Therefore, it appears likely that a flux
of nickel to herbivore and carnivore trophic levels is specifically
facilitated by the presence of plants that hyperaccumulate this metal.
The results may be relevant to the development of phytoremediation and
phytomining technologies, which use plants to extract metals from the
soil.
Reveived 22 August 2002; accepted 2 April 2003.
R1D="
Correspondence to: A. J. Pollard, e-mail:joe.pollard@furman.edu 相似文献
125.
Restoration of Landscape Structure Altered by Fire Suppression 总被引:2,自引:0,他引:2
William L. Baker 《Conservation biology》1994,8(3):763-769
There is increasing interest in applying landscape ecological research to the management of wildlands, particularly regarding the negative effects of fragmentation and the benefits of corridors. Patch-producing large disturbances, such as fires and floods, produce a spatial mosaic structure in landscapes to which many species are sensitive. Management of the spatial structure of the patch mosaic has seldom been an explicit concern, however, in part because of insufficient knowledge about bow this spatial structure is affected by alterations in the disturbance regime. Yet the patch mosaic structure of many landscapes has been altered by disturbance control (such as fire suppression), and there is substantial interest in restoring natural disturbance regimes in some wildland landscapes. It has been proposed that, in landscapes subjected to decades of fire suppression, simple reinstatement of the natural fire regime may lead to adverse effects because fuel buildup during fire suppression may result in unusually large fires. It has also been proposed that the use of small prescribed fires may be an effective approach to restoration of landscapes subjected to fire suppression. Here I use a spatial GIS-based simulation model to analyze the effects of reinstating a natural fire regime in the Boundary Waters Canoe Area, Minnesota, after 82 years of fire suppression. The simulation experiment suggests that suppression can be expected to significantly alter landscape structure, but landscape structure can generally be restored within 50–75 years by reinstating the natural fire regime. Unusually large fires would probably hasten the restoration of landscape structure, while small prescribed fires will not restore the landscape but instead will produce further alteration. 相似文献
126.
Summary The loud and elaborate songs of male songbirds are throught to serve in territorial defense and to stimulate reproductive behavior in the female. We report here that in contrast to several other species, song alone is inadequate to induce sexual (lordosis) behavior in female indigo and lazuli buntings (Passerina cyanea and P. amoena); they require a more elaborate stimulus configuration to develop the full expression of sexual receptivity as indicated by a stereotyped copulation solicitation display. A live male must be present near the female, singing must ensue, and in addition a second and unique vocal utterance must be heard by the female; this is a soft buzzy-sounding vocalization, audible for no more than a few meters, not recognized previously as a critical arousal signal of the male songbird repertoire. Females also utter similar soft sounds in an intimate vocal exchange with the male leading to solicitation of copulation. 相似文献
127.
Collection and culture of the large lobate ctenophore Mnemiopsis mccradyi Mayer is described, including the requirements for successful development of larvae. Particular attention must be given to the collection of these delicate animals, the handling and provision of live microzooplankton of suitable size for the larvae, and the provision of food densities for the adults which neither stimulate “wasteful” feeding nor limit their growth. Although these ctenophores will ingest detritus and algal cells in high concentration, they lost weight at the same rate as starved individuals unless provided with living zooplankton. Under optimum conditions, specimens would lay eggs within 13 days of their own birth. By the 17th day they laid eggs daily, and had produced an average of 8,000 eggs within 23 days after birth. The maximum number of eggs laid by a single wild individual within 24 h after being brought into the laboratory was 10,000. Their high fecundity, rapid generation time, and ability to self-fertilize help to explain their sudden appearance in bloom proportions at periods of high food concentration in the environment, often referred to in the literature. 相似文献
128.
Myron Charles Baker Daniel B. Thompson Gregory L. Sherman Michael A. Cunningham 《Behavioral ecology and sociobiology》1981,8(1):65-69
Summary Nonmigratory populations of Whitecrowned Sparrows in coastal California exhibit dialects in territorial male songs that are stable in space and time. By field playback experiments, we tested a prediction from the hypothesis that male aggressive interactions prohibit mixing of song dialects. Playback of the home dialect Clear song to territorial males singing the Clear dialect resulted in less response than that given to playback of the neighboring Buzzy dialect. Response to both Buzzy and Clear dialect songs by target Clear males, however, was greater than that given to the Bodega dialect recorded 55 km away (Figs. 2 and 3). We conclude that these results are consistent with the hypothesis that male-male aggressive interactions play an important role in reducing dialect mixing. 相似文献
129.
Ecological role for pteroenone,a novel antifeedant from the conspicuous antarctic pteropod Clione antarctica (Gymnosomata: Gastropoda) 总被引:1,自引:0,他引:1
Dense populations of the antarctic pteropod Clione antarctica (Smith) offer a rich source of potential nutrients and energy to planktivorous predators. Nonetheless, antarctic fish do not prey on C. antarctica. Employing flash and high-pressure liquid chromatographic techniques, a linear -hydroxyketone, pteroenone (C14H24O2) was isolated from whole tissues of C. antarctica. When embedded in alginate food pellets at ecologically relevant concentrations, pteroenone caused significant feeding deterrence in Pagothenia borchgrevinki and Pseudotrematomas bernacchii, two antarctic fish known to feed on planktonic organisms. Concentrations of pteroenone were variable between pteropods (0.056 to 4.5 mg ml-1 tissue), but even those individuals with the lowest natural concentration contained levels five-fold greater than the lowest effective feeding-deterrent concentration (0.012 mg ml-1 alginate). Chemical analysis indicated that the primary dietary item of the carnivorous C. antarctica, the shelled pteropod Limacina helicina, does not contain pteroenone. This suggests that C. antarctica does not derive this defensive compound from its diet. This is the first example of a defensive secondary metabolite in a pelagic gastropod. 相似文献
130.
Forage and soil molybdenum (Mo) were measured in the vicinity of a Mo processing plant in southwestern Pennsylvania, USA. Molybdenum concentrations in red clover plants (Trifolium pratense L.), measured at 23 sites, ranged from 1.1 to 56.6 mg kg–1. Fourteen of the 23 sites sampled had red clover plants with Mo concentrations over the threshold value of 6 mg kg–1. Red clover Cu:Mo concentration ratios were below the recommended ratio of 4 in 19 of the sites. The low Cu:Mo values, along with high plant Mo concentrations, indicates that there is a potential risk of molybdenosis in ruminant animals in this area. Acid digested (sorbed) soil Mo concentrations, measured at 30 sites, ranged from 7.0 (background level) to 131 mg kg–1. Using the Baker Soil Test (BST) extract, molybdenum soil concentrations ranged from 0.01 to 3.99 mg kg–1. Regression equations were developed to predict plant uptake of soil Mo based on the red clover plant, soil extracts and soil pH data. The R-squared values for predicting plant uptake were 81.9% for the BST extract and 81.6% for the acid digestion extract plus soil pH. Based on the above results, a protocol has been implemented for assessing the risk of high soil Mo near this Mo processing plant. 相似文献