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151.
Comparisons of forager distributions from matched honey bee colonies in suburban environments 总被引:4,自引:0,他引:4
Keith D. Waddington Thomas J. Herbert P. Kirk Visscher Monica Raveret Richter 《Behavioral ecology and sociobiology》1994,35(6):423-429
We conducted experiments designed to examine the distribution of foraging honey bees (Apis mellifera) in suburban environments with rich floras and to compare spatial patterns of foraging sites used by colonies located in the same environment. The patterns we observed in resource visitation suggest a reduced role of the recruitment system as part of the overall colony foraging strategy in habitats with abundant, small patches of flowers. We simultaneously sampled recruitment dances of bees inside observation hives in two colonies over 4 days in Miami, Florida (1989) and from two other colonies over five days in Riverside, California (1991). Information encoded in the dance was used to determine the distance and direction that bees flew from the hive for pollen and nectar and to construct foraging maps for each colony. The foraging maps showed that bees from the two colonies in each location usually foraged at different sites, but occasionally they visited the same patches of flowers. Each colony shifted foraging effort among sites on different days. In both locations, the mean flight distances differed between colonies and among days within colonies. The flight distances observed in our study are generally shorter than those reported in a similar study conducted in a temperate deciduous forest where resources were less dense and floral patches were smaller. 相似文献
152.
Renzo D'Amelio Claudio Giorlandino MD Liana Masala Massimo Garofalo Monica Martinelli Giuseppe Anelli Lucio Zichella 《黑龙江环境通报》1991,11(2):69-75
The authors compare the diagnostic possibilities of fetal transabdominal echocardiography versus transvaginal echocardiography. A larger diagnostic capacity is verified in different gestation ages with transvaginal probe between the 11th and 14th week of gestation. The results are emphasized by colour Doppler. 相似文献
153.
Kumar S Dagar SS Mohanty AK Sirohi SK Puniya M Kuhad RC Sangu KP Griffith GW Puniya AK 《Die Naturwissenschaften》2011,98(6):457-472
Methanogens, the members of domain Archaea are potent contributors in global warming. Being confined to the strict anaerobic environment, their direct cultivation as
pure culture is quite difficult. Therefore, a range of culture-independent methods have been developed to investigate their
numbers, substrate uptake patterns, and identification in complex microbial communities. Unlike other approaches, fluorescence
in situ hybridization (FISH) is not only used for faster quantification and accurate identification but also to reveal the
physiological properties and spatiotemporal dynamics of methanogens in their natural environment. Aside from the methodological
aspects and application of FISH, this review also focuses on culture-dependent and -independent techniques employed in enumerating
methanogens along with associated problems. In addition, the combination of FISH with micro-autoradiography that could also
be an important tool in investigating the activities of methanogens is also discussed. 相似文献
154.
Thomas Chouvenc Caroline A. Efstathion Monica L. Elliott Nan-Yao Su 《Die Naturwissenschaften》2012,99(11):949-958
Subterranean termites live in large groups in underground nests where the pathogenic pressure of the soil environment has led to the evolution of a complex interaction among individual and social immune mechanisms in the colonies. However, groups of termites under stress can show increased susceptibility to opportunistic parasites. In this study, an isolate of Aspergillus nomius Kurtzman, Horn & Hessltine was obtained from a collapsed termite laboratory colony. We determined that it was primarily a saprophyte and, secondarily, a facultative parasite if the termite immunity is undergoing a form of stress. This was determined by stressing individuals of the Formosan subterranean termite Coptotermes formosanus Shiraki via a co-exposure to the virulent fungal parasite Metarhizium anisopliae (Metch.) Sorokin. We also examined the dynamics of a mixed infection of A. nomius and M. anisopliae in a single termite host. The virulent parasite M. anisopliae debilitated the termite immune system, but the facultative, fast growing parasite A. nomius dominated the mixed infection process. The resource utilization strategy of A. nomius during the infection resulted in successful conidia production, while the chance for M. anisopliae to complete its life cycle was reduced. Our results also suggest that the occurrence of opportunistic parasites such as A. nomius in collapsing termite laboratory colonies is the consequence of a previous stress, not the cause of the stress. 相似文献
155.
Monica Montory Evelyn Habit Pilar Fernandez Joan O. Grimalt Ricardo Barra 《环境科学学报(英文版)》2012,24(2):221-227
This pilot study documented the occurrence and levels of brominated flame retardants in the tissues of farmed and wild salmon in southern Chile. Samples of Coho salmon and rainbow trout were obtained from fish farms, rivers and lakes in the Patagonia in Aysen Region, Chile. The samples were analyzed by Gas Chromatography Negative Chemical Ionization Mass Spectrometry for the different polybrominated diphenyl ether (PBDE) congeners. Contaminants were observed in all the samples, and the congeners BDE 17, 28, 47 and 66 were observed in all both farmed and wild samples. The concentrations were higher in the farmed Coho salmon, presenting significant differences with wild salmon. The levels reached 182 pg/g wet weight (ww) vs. 120 ww. In the case of the rainbow trout, the concentrations were lower, although the congener profile was quite similar. The levels reached an average of 100 pg/g ww in the farmed fish versus 110 pg/g ww in wild fish, and no significant difference was observed between the species. In both species, the congener with the highest concentration was BDE 47. Based on this information, the BDE flow was estimated for commerce, which is a form of pollutant transport not usually considered in POP pollution studies. A preliminary estimation indicated that the quantity of PBDEs mobilized by commerce was in the order of kg, and in the case of Chile might reach almost 1 kg. 相似文献
156.
157.
The current study represents a preliminary investigation made into the influence of cattle grazing in the area of a bauxite
quarry (Comarnic–Poieni, Romania) on the cow milk chemistry. Weathering and surface runoff in the bauxite quarry contaminate
the local chemistry of the soil, vegetation and water. During cattle transhumance, cyclic feeding patterns occur, with grazing
alternating between clean pastures and the area of the quarry. Soil and water samples were collected from the contaminated
area of the quarry. Raw milk samples were collected during two stages, corresponding to the periods of grazing on clean pasture
and the quarry area, respectively. Based on the obtained data, the relationship between cattle grazing and the composition
of milk was interpreted. Preliminary results indicated a direct correlation of increased concentration of Al in the milk,
following grazing in the bauxite quarry. 相似文献
158.
Monica R. Lara 《Marine Biology》2008,154(1):51-64
Larval fishes likely use a variety of settlement cues to locate and navigate toward the habitats they will inhabit as juveniles.
Information about the morphology and state of development of the sensory organs of larval stages of fishes provides insight
into their capabilities at the time of settlement. The peripheral olfactory organ of wild-caught late-stage larvae and early
juveniles and some adults of 14 species of the Caribbean reef fishes wrasses (Labridae), parrot fishes (Scaridae) and damselfish
(Pomacentridae) were examined using scanning electron microscopy and compared in terms of settlement specificity. Ages in
days after hatching and days post-settlement were determined from the otoliths. Morphology of the nares and the olfactory
epithelium are described for these species by stage. The separation of the anterior and posterior nares occurred before settlement
in the labrids but in some specimens of scarids this separation was not complete by the time of settlement. Densities of ciliated
and microvillous receptor cells and non-sensory ciliated epithelial cells were calculated. Densities of ciliated receptor
cells ranged from 0.389 μm−2 in a specimen of Thallasoma bifasciatum to 0.0057 μm−2 in Bodianus rufus and of microvillous receptor cells from 0.038 μm−2 in a Clepticus parrae juvenile to 0.266 μm−2 in a juvenile Doratonotus megalepis. Densities of non-sensory cilia, also associated with high olfactory ability, were also high. The olfactory organ in wrasses
is well developed prior to settlement and is comparable to that of adult fishes. The possible role of olfaction in larval
schooling, reef cue detection and orientation toward habitat at settlement is discussed.
相似文献
Monica R. LaraEmail: |
159.
Susan E. Ford V. Monica Bricelj Christophe Lambert Christine Paillard 《Marine Biology》2008,154(2):241-253
The known negative effects of shellfish toxin-producing dinoflagellates on feeding, burrowing and survival of some bivalve
mollusks has prompted questions concerning whether they might also impair the internal defense system of affected bivalves
and make them more susceptible to disease agents. The primary components of the cellular defense system are hemocytes. Many
toxic dinoflagellates are too large to be ingested whole by hemocytes and would most likely be exposed to intracellular toxins
only after the algae are consumed, broken down, and the water-soluble toxins, released. Therefore, we conducted a series of
experiments in which hemocytes from two suspension-feeding bivalves—the Manila clam, Ruditapes philippinarum, and the softshell clam, Mya arenaria—were exposed in vitro to filtered extracts of one highly toxic paralytic shellfish toxin (PST)-producing and one nonPST-producing
strain of Alexandrium tamarense (isolates PR18b, 76 ± 6 STXeq cell−1 and CCMP115, with undetectable PST, respectively). We measured adherence and phagocytosis, two hemocyte attributes known
to be inhibited by bacterial pathogens and other stressors. We found no measurable effect of a cell-free extract from a highly
concentrated suspension of the PST-producing strain on hemocytes of either bivalve species. Instead, extract from the nonPST-producing
strain had a consistent negative effect on both clams, resulting in significantly lower adherence and phagocytosis compared
to strain PR18b and filtered seawater controls. The bioactive compound produced by strain CCMP115, which has yet to be characterized,
may be similar to the PST-independent allelopathic compounds described for Alexandrium spp., which act on other plankters. These compounds and those produced by other harmful algae are known to cause immobilization,
cellular deformation and lysis of co-occurring target organisms. Thus, nonPST producing Alexandrium spp., which do not cause paralysis and burrowing incapacitation of clams, may still produce a compound(s) that has negative
effects not only on hemocytes, but on other molluscan cell types and their functions, as well. 相似文献
160.
Natasha Tigreros Monica A. Mowery Sara M. Lewis 《Behavioral ecology and sociobiology》2014,68(9):1539-1547
While the phenomenon of male mate choice has attracted considerable attention in the last two decades, whether this sexual selection mechanism could drive the evolution of female ornaments remains poorly understood. Here, we used experimental manipulation of female wing coloration to investigate male mate choice in Pieris rapae, a gift-giving butterfly. Further, we tested whether males’ nutritional status influenced their mating preferences by subjecting larvae to short periods of starvation. We found that males showed significantly more mating approaches toward control females with more colorful wings (higher pteridine content), and that this preference was strongest in low-nutrition males. Additionally, a study of field-collected females revealed that pteridine-based wing coloration was positively correlated with female egg load, which suggests such ornaments may signal female quality. Pteridine-based ornaments are widespread in nature, however their potential as honest signals in male mate choice remains largely unexplored. This work furthers our understanding of how male mate choice and female ornamentation may evolve in species whose mating systems include nutritional nuptial gifts. 相似文献