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1.
W. J. Etges  W. B. Heed 《Oecologia》1987,71(3):375-381
Summary Chromosomally polymorphic populations of Drosophila mojavensis from Baja California feed and breed on agria cactus, Stenocereus gummosus; whereas, monomorphic Arizona populations are associated exclusively with organ pipe cactus, S. thurberi. The effects of this host plant shift in expanding the kinds of feeding and breeding sites were assessed by manipulating larval density and recording differences in egg to adult development time and viability, and adult thorax size in both populations on artificially rotted substrates of both cactus species. Older agria rots increased development time but had no effect on viability. Organ pipe rots were qualitatively poorer substrates than agria rots for both monomorphic and polymorphic populations of D. mojavensis, especially at higher larval densities causing longer egg to adult development times, lower viabilities, and smaller thorax sizes than agria.The Baja population expressed shorter development times, higher viabilities, and smaller thorax sizes than the Arizona population on both cactus substrates. No evidence for cactus host race formation was found. The Baja population was less sensitive to increasing larval densities for all fitness characters studied on both cactus substrates indicating greater developmental homeostasis than in the monomorphic Arizona population. These data support the hypothesized central-marginal population structure within this species coincident with the distribution of host plants and lend insight into the process of adaptive divergence at different life history stages caused by host plant shifts.  相似文献   

2.
The geographical dichotomy hypothesis suggests that columnar cacti in the tropics depend primarily on bats for pollination. This dependence may to be less in the outer tropics where many columnar cactus species (or their populations) show a relatively generalized pollination system with both nocturnal (moths and bats) and diurnal pollinators (bees and hummingbirds) (geographical dichotomy hypothesis). This hypothesis has been mostly tested in the northern tropics; nonetheless, our knowledge of columnar cactus species inhabiting the southern tropics is still scarce. The aim of this project was to evaluate the pollination biology of Oreocereus celsianus, a columnar cactus with restricted distribution in the subtropical Andes, to determine if the pollination system of this cactus tends to be more generalized than specialized because of the geographical position where it occurs. Observations of frequency of visit showed that Patagona gigas (Giant Hummingbird) is the main pollinator of the flowers, visiting them when they are opening (afternoon of the first day). Bees, wasps and moths were occasional visitors of the flowers. None of them seem to act as pollinator. Autogamy, geitonogamy and xenogamy treatments produced high fruit set, showing that O. celsianus has an unusual mixed mating system. The results suggest that this Andean columnar cactus is partially specialized on hummingbirds, with most pollination service performed by a single species, and it has the capacity of selfing (??fail-safe?? pollination system). This mixed mating system (both outcrossing and selfing) may be a response to the unpredictable environment of the Prepuna in the subtropical Andes.  相似文献   

3.
The considerable floral diversity present in the cactus family has often been associated with the specificity of its pollinators. However, many cactus pollination systems are generalized as their flowers are pollinated by a wide spectrum of animals. For example, cactus species with white flowers, nocturnal anthesis and extended floral cycles would present generalized pollination systems in which both nocturnal and diurnal visitors could be effective pollinators. In this article, we tested this hypothesis by studying the pollination biology of Echinopsis schickendantzii, an Andean cactus with sphingophilous flowers. In addition, we evaluated whether the cactus’s pollination system is complementary or redundant regarding the relative contributions of nocturnal and diurnal pollinators. Specifically, we studied the floral cycle, the reproductive system and the pollination effectiveness of floral visitors. The flowers of E. schickendantzii are self-incompatible; they opened at crepuscule and have an extended floral cycle. Moths were frequent visitors at night, whereas bees were frequent visitors during the day; both were effective pollinators of the cactus. Our results indicated that the flowers of this species present phenotypic, functional and ecological generalization, and their fruit set is determined by the contributions of both pollinator functional groups, i.e., they have complementary pollination systems. These results support the hypothesis that cacti in the extra-tropical deserts of South America have generalized pollination systems.  相似文献   

4.
In view of the reported high prevalence of otitis media and mastoiditis in the present-day Indian inhabitants of Arizona, when an opportunity arose to examine the skulls of prehistoric Indians in the collection of the Arizona State Museum, University of Arizona, Tucson, Arizona, it was thought that determining the prevalence of mastoiditis in them might be helpful in the treatment and prevention of mastoid infections in the present-day population. Our findings are compared with those of two other studies of mastoiditis in prehistoric Indians in another area of the United States.  相似文献   

5.
Yeast communities in necroses of organpipe cactus (Stenocereus thurberi) were surveyed at 3 localities in Arizona. Quantitative analysis of random samples allows comparisons of the types and numbers of yeasts at 3 levels: within plants, between plants within a locality, and between localities. The analysis shows that the major source of variability is between plants. This pattern is identical with the pattern shown by agria cactus (Stenocereus gummosus) and is thought to be due to sampling different successional stages. No significant differences in estimates of the effective number of yeast species (ENS) in agria and organpipe samples were found. Comparisons of agria, organpipe, and prickly pear (Opuntia) cacti support the hypothesis that cactus chemistry is an important determinant of the yeast community structure which, in turn, is an important determinant of the diversity ofDrosophila species which utilize necrotic cacti as feeding and breeding substrates.  相似文献   

6.
《Plains anthropologist》2013,58(65):211-223
Abstract

Peyotism in the United States was dependent upon the Peyote cactus, Lophophora williamsii, which has a very limited distribution along the lower Rio Grande River, centered around Laredo, Texas. The Lipan Apache Indians in the vicinity of Laredo,,1760to 1850’s, learned of the properties of Peyote and the ritual for its use from Coahuiltecan-speaking Carrizo and Tonkawa and in turn taught Peyotism to the Comanche and Kiowa.  相似文献   

7.
Four adult skeletal samples from the states of Uttar Pradesh, Andhra Pradesh, and Bihar in India have been studied for the incidence of mylohyoid bridge. The incidence, varying between 2.98% and 7.14%, has been compared with frequencies reported for other populations of the world. The range of variation for Indians, as a whole, falls within the lower levels of the spectrum of worldwide variation for this trait, ranging between 0.47% for French Europeans and 33.8% observed among Plains American Indians. While noting its possible significance for clinical purposes, the suitability of the mylohyoid bridge as a population genetic marker has been discussed. It is emphasized that its use as a genetic marker in isolation of other discrete traits has serious limitations. For meaningful population definition and relationships as many discrete variants as possible ought to be utilized.  相似文献   

8.
Ants are attracted to extrafloral nectaries subtending reproductive organs of Ferocactus acanthodes var. lecontei (Cactaceae) in central Arizona. Extrafloral nectar produced by these glands contained amino acids, sugars, and water. Nectar quality and composition varied temporally in relation to plant reproductive phenology. The number of nectar glands on a barrel cactus did not change significantly, however; the mass of nectar produced per gland increased significantly with immature fruit production. Of the three sugars present in extrafloral nectar (fructose, glucose, and sucrose), only glucose occurred at a higher concentration in June, when immature fruits first appeared on barrel cactus. Amino acid concentration and composition in extrafloral nectar of barrel cactus did not change significantly over time. Ant density on barrel cactus increased significantly from mid-May to mid-June at two field sites. Water availability per nectar gland increased 158% from May to June. Water plays an important role in attracting ants to barrel cacti.  相似文献   

9.
The purpose of this study was to extend and refine our knowledge of the geographical distribution and natural host relationships of the arenaviruses associated with woodrats indigenous to Arizona. Antibody to a Tacaribe serocomplex virus was found in 112 of 1,250 white-throated woodrats, five of 208 Mexican woodrats, one of 114 Stephen's woodrats, and none of 862 other rodents captured at 51 sites in 10 counties in Arizona. Of the 112 antibody-positive white-throated woodrats, 109 (97.3%) were captured within extensive, dense patches of prickly pear cactus and cane cholla in three counties in mid-central Arizona. Analysis of the serological and zoographical data suggested that white-throated woodrats usually become infected early in life and that the distribution of antibody-positive white-throated woodrats in Arizona is not linked to a specific biome.  相似文献   

10.
The termwisakon, recorded among Southeastern Algonquian Indians in the seventeenth and eighteenth centuries, frequently has been iden tified as one of several plant species. However, it appears thatwisakon referred not to any particular plant species but to a general category of substances that included both plant and nonplant materials. The misunderstanding illustrates some of the problems and procedures involved in the exchange and integration of botanical information by Europeans and Indians in the early culture contact situation.  相似文献   

11.
Previous studies have suggested that all populations of cactophilic Drosophila mojavensis prefer pitaya agria cactus, Stenocereus gummosus, over all other potential hosts for feeding and breeding, including populations that inhabit areas where no agria grows. We sampled five geographically isolated populations of D. mojavensis from nature to assess host choice within and between populations. Host choice tests were performed in a laboratory olfactometer by allowing adult D. mojavensis to choose between plumes of synthetic volatile cocktails of two widespread host cacti. Overall, each population showed significant preference for agria volatiles with one exception: a mainland Sonora population that uses organ pipe cactus in nature exhibited preference for organ pipe volatiles, suggesting a possible shift in host preference. The degree of preference for agria volatiles was greatest in a population from southern California that use California barrel cactus as a host. Since southern Californian populations of D. mojavensis are thought to be derived from those in Baja California, preference for agria volatiles is considered a retained ancestral trait. Three populations from Baja California and mainland Mexico that use agria in the wild expressed lower, but similar preferences for agria volatiles. Because populations of D. mojavensis are ancestral to those in mainland Mexico, Arizona, and California, the shift from agria to alternate hosts has not been accompanied by strong changes in host preference behavior.  相似文献   

12.
Spineless cactus is a useful feed for various animal species in arid and semiarid regions due to its adaptability to dry and harsh soil, high efficiency of water use and carbohydrates storage. This meta-analysis was carried out to assess the effect of spineless cactus on animal performance, and develop and evaluate equations to predict dry matter intake (DMI) and average daily gain (ADG) in meat lambs. Equations for predicting DMI and ADG as a function of animal and diet characteristics were developed using data from eight experiments. The dataset was comprised of 40 treatment means from 289 meat lambs, in which cactus was included from 0 to 75% of the diet dry matter (DM). Accuracy and precision were evaluated by cross-validation using the mean square error of prediction (MSEP), which was decomposed into mean bias, systematic bias and random error; concordance correlation coefficient, which was decomposed into accuracy (Cb) and precision (ρ); and coefficient of determination (R2). In addition, the data set was used to evaluate the predicting accuracy and precision of the main lamb feeding systems (Agricultural and Food Research Council, Small Ruminant Nutritional System, National Research Council and Institut National de la Recherche Agronomique) and also two Brazilian studies. The DMI, CP intake (CPI), metabolizable energy (ME) intake and ADG increased when cactus was included up to 499 g/kg DM (P<0.001). In contrast, animals fed high levels of cactus (>500 g/kg DM) had a decreased DMI, CPI and NDF intake, but increased feed efficiency (P<0.001) and similar ADG compared with those without cactus addition. The DMI was positively correlated with initial BW, final BW, concentrate and ADG, while it was negatively correlated with cactus inclusion and ME of the diet. On other hand, ADG was positively correlated with DMI, initial and mean BW and concentrate, and it was negatively correlated with cactus inclusion. The two developed equations had high accuracy (Cb of 0.95 for DMI and 0.94 for ADG) and the random error of MSEP was 99% for both equations. The precision of both equations was moderate, with R2 values of 0.53 and 0.50 and ρ values of 0.73 and 0.71 for DMI and ADG, respectively. In conclusion, the developed equation to predict DMI had moderate precision and high accuracy, nonetheless, it was more efficient than those reported in the literature. The proposed equations can be a useful alternative to estimate intake and performance of lambs fed cactus.  相似文献   

13.
Starch gel electrophoresis revealed that the alcohol dehydrogenase (ADH-2) locus was polymorphic in two populations (from Agua Caliente, California and the Grand Canyon, Arizona) of cactophilic Drosophila mojavensis that utilize barrel cactus (Ferocactus acanthodes) as a host plant. Electromorphs representing products of a slow (S) and a fast (F) allele were found in adult flies. The frequency of the slow allele was 0.448 in flies from Agua Caliente and 0.659 in flies from the Grand Canyon. These frequencies were intermediate to those of the low (Baja California peninsula, Mexico) and high (Sonora, Mexico and southern Arizona) frequency Adh-2S populations of D. mojavensis that utilize different species of host cacti.  相似文献   

14.
The Atacama Desert is one of the most stressful environments worldwide and represents a strong barrier for the establishment of native and non-native plants. In this study, we report the establishment of a non-native annual plant through facilitation by a native endemic cactus in a relatively undisturbed coastal area in north-central Chile. Soil collected under Eulychnia acida contained more available nutrients (N, P and K), water, and soluble salts than soils collected away from E. acida. Co-occurrence analyses showed a strong positive spatial association (facilitation) between the native cactus E. acida and the non-native annual, Mesembryanthemum crystallinum. The aboveground biomass of M. crystallinum individuals was 4-fold higher under the influence of E. acida. Native halophytes occasionally shared the cactus understory with the non-native species, but dominant native shrubs and perennial herbs did not co-occur with the cactus at scales of 1 and 4 m2. All these results support facilitation of the native cactus on the non-native herb. The combination of direct and indirect positive effects could explain the assembly of the non-native annual plant in these undisturbed areas of the Atacama Desert and have major implications on M. crystallinum capacity to colonize new areas.  相似文献   

15.
Cactus and succulent Euphorbia plants have green stems that are exposed to sunlight over long periods. Previous research demonstrated that barking injuries occur to stem surfaces of 20 species of cacti in the Americas. For these 20 cactus species the amounts of injuries were related to annual amounts of sunlight exposure on surfaces. Cacti with many injuries had high mortality rates. Data herein show that stem surfaces of 20 species of Euphorbia in South Africa have identical surface injuries as for cacti. Euphorbia plants at 30°S show a mean ratio of scale and bark injuries of 3.5:1 of equatorial-facing to polar-facing surfaces, a ratio is similar to the 4:1 of annual sunlight exposure ratio at that latitude. Results show that Euphorbia stems have injuries on younger tissues than cactus species. Thus, Euphorbia stems are more sensitive than cactus stems. Euphorbia species with most stem injuries had smooth (non-undulate) surfaces, a one-celled epidermal cell layer only, cortex cells that abutted the epidermis, and initial injuries that involved only epidermal cells. This is the first report of identical stem surface injuries to Euphorbia species that are identical to surface injuries to cactus species worldwide. Moreover, the amounts on stem injuries on Euphorbia and long-lived, columnar cactus species are highly correlated with relative amounts of sunlight on stem surfaces over the annual cycle. These results suggest that these species are good bio-indicators of annual sunlight exposure.  相似文献   

16.
Divergence in host adaptive traits has been well studied from an ecological and evolutionary perspective, but identification of the proximate mechanisms underlying such divergence is less well understood. Behavioral preferences for host plants are often mediated by olfaction and shifts in preference may be accompanied by changes in the olfactory system. In this study, we examine the evolution of host plant preferences in cactophilic Drosophila mojavensis that feeds and breeds on different cacti throughout its range. We show divergence in electrophysiological responses and olfactory behavior among populations with host plant shifts. Specifically, significant divergence was observed in the Mojave Desert population that specializes on barrel cactus. Differences were observed in electrophysiological responses of the olfactory organs and in behavioral responses to barrel cactus volatiles. Together our results suggest that the peripheral nervous system has changed in response to different ecological environments and that these changes likely contribute to divergence among D. mojavensis populations.  相似文献   

17.
One of the most common types of cactus flower in the southwestern United States is the large, colorful, cup-shaped flower.Echinocereus fasciculatus var.boyce-thompsonii in Arizona is a representative of this class of flowers. Its flowers are visited by three common types of insect visitors: medium-sized bees, small solitary bees, and beetles. All three types of visitors come into contact with the pollen, but only the mediumsized bees regularly touch the stigma in their visitations. The main effective pollinators are therefore the medium-sized bees (Megachile, etc.).Ferocactus wislizenii has a similar floral mechanism and is likewise pollinated mainly by medium-sized bees (Megachile, Lithurge, Diadasia, etc.).Pollination of North American Cacti, 1.  相似文献   

18.
The Western Hemisphere genus Pseudomorpha Kirby 1825 was last revised by Notman in 1925 based on only a few known species (22) and paltry few specimens (73); other authors have added an additional six species represented by 53 additional specimens since 1925. Baehr (1997) assigned three species from Australia to this genus, albeit in a new subgenus, Austropseudomorpha Baehr 1997. A recent study of collections from throughout the Americas (1757 specimens) has revealed numerous new species that can be arrayed across 19 species groups based on a suite of attributes, some used by Notman and others newly discovered. A taxonomic revision of the species contained in one of these species groups, santarita, is provided herein, as well as a distributional synopsis of the remaining 18 species groups. New species described herein are as follows, each with its type locality: Pseudomorpha huachineras p. n., Arroyo El Cocono, Sierra Huachinera, Sonora, México; P. patagonia sp. n., Madera Canyon, Santa Rita Mountains, Arizona; P.penablanca sp. n., Peña Blanca Lake, Arizona; P. pima sp. n., Madera Canyon (lower), Santa Rita Mountains, Arizona; P. santacruz sp. n., Madera Canyon, Santa Rita Mountains, Arizona; and P. santarita sp. n., Santa Rita Ranch, Santa Rita Mountains, Arizona.  相似文献   

19.
The Duffy (Fy) antigens act as receptors for chemokines as well as for Plasmodium vivax to invade human RBCs. A recent study has correlated the occurrence of the FY*A allele of Duffy gene with decreased susceptibility to vivax malaria, but no epidemiological correlation between the distribution of FY*A allele and incidences of vivax malaria has been established so far. Furthermore, if such correlations exist, whether natural selection has mediated the association, is an important question. Since India is highly endemic to P. vivax malaria with variable eco-climatic and varying vivax malaria epidemiology across different regions, such a question could well be answered in Indians. For this, we have genotyped the FY gene at the −33rd and the 125th nucleotide positions in 250 Indians sampled from six different zonal plus one tribal population covering the whole of India and studied possible correlations with eco-climatic and vivax malaria incidences. No FY*O allele was found, however, both the FY*A and FY*B alleles forming FY*A/FY*A, FY*A/FY*B and FY*B/FY*B genotypes were widely distributed among Indians. Five out of seven population samples significantly deviated from the Hardy-Weinberg equilibrium expectation, and two alleles (FY*A and FY*B) and the homozygote genotype, FY*B/FY*B were clinally distributed over the population coordinates. Furthermore, vivax malaria incidences over the past five years were significantly negatively and positively associated with the frequencies of the FY*A and FY*B alleles, respectively. The Northern Indians were highly differentiated from the other zonal population samples at the FY gene, as evidenced from the reconstructed Neighbor-Joining phylogenetic tree. The results specify the role of natural selection in the distribution of FY gene polymorphism in India. Furthermore, the hypotheses on the part of the FY*A allele in conferring protection to vivax malaria could be validated following population genetic studies in a vivax malaria epidemiological setting, such as India.  相似文献   

20.
The objective of this study was to evaluate the performance and nutrient digestibility of feedlot Santa Inês sheep fed with increasing levels (0, 25, 50, 75, 100% dry matter basis) of cactus pear (Opuntia ficus indica, Mill) as a replacement for corn. Forty-five male (non-castrated) Santa Inês sheep, averaging 27.50 ± 0.48 kg body weight (BW) at the beginning of the study, were used in this trial. A completely randomized block design with nine replicates per treatment was used. The intakes of DM, OM, CP, EE, TC, NFC, TDN and ME were quadratic, while the intakes of mineral matter (MM) and NDF increased linearly with increased levels of cactus pear in the diet. The voluntary intake of water decreased with increased levels of cactus pear in the diet. Increased levels of cactus pear in the diet increased the apparent digestibility of DM, OM, CP, NDF, and TC linearly, but did not influence the digestibility of EE or NFC. Daily weight gain (DWG) and feed efficiency decreased linearly with increased levels of cactus pear in the diet. The replacement of corn by cactus pear does not affect the conversion of the feed. Overall, increased levels of cactus pear in the diet of these sheep favours a high digestibility of nutrients, improves the quality of forage, reduces the voluntary intake of water, and thus represents an important source of fodder and water reserves for use in semiarid regions.  相似文献   

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