An experimental test of Dodson's hypothesis that Ambystoma (a salamander) and Chaoborus (a phantom midge) have complementary feeding niches

1979 ◽  
Vol 57 (5) ◽  
pp. 1091-1097 ◽  
Author(s):  
Louis Giguère
Keyword(s):  
Food Source ◽  
Complementary Feeding ◽  
Zooplankton Community ◽  
Dry Weight ◽  
Fourth Instar ◽  
Crop Content ◽  
Diaphanosoma Brachyurum ◽  
Main Food Source ◽  
Daphnia Rosea ◽  
Phantom Midge

The removal from an alpine pond of eggs of the salamander Ambystoma gracile had a large impact on the zooplankton community. The pond was dominated by the large Daphnia rosea, while a nearby pond, from which salamander eggs were not removed, was dominated by the small Diaphanosoma brachyurum. Chaoborus trivittatus crop content analyses revealed that in the experimental pond, food intake of second and third instars was low. In the fall, fourth instars were scarce and their dry weight was 50% lower than those in the previous year or those of the control pond.When larval Ambystoma is abundant, it preys heavily upon the cladocerans Holopedium gibberum and Daphnia, which are too large for Chaoborus to eat. Whereas Holopedium appears not to be much affected by the intensity of Ambystoma predation, the reduction in density of Daphnia leads to increased density of Diaphanosoma, possibly because of reduced competitive interaction. Diaphanosoma is the main food source, when available, of second and third instar Chaoborus. In this indirect way, Chaoborus depends on vertebrate predation to reach successfully its fourth instar. This lends support to Dodson's hypothesis of complementary feeding niches.

scholarly journals Accelerating the Morphogenetic Cycle of the Viral Vector Aedes aegypti Larvae for Faster Larvicidal Bioassays

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
José Domingos Fontana ◽  
Rafael Lopes Ferreira ◽  
Tatiana Zuccolotto ◽  
Cibelle de Borba Dallagassa ◽  
Leonardo Pellizzari Wielewski ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Room Temperature ◽  
Food Source ◽  
Viral Vector ◽  
Low Cost ◽  
Mosquito Species ◽  
Larval Growth ◽  
Fourth Instar ◽  
Coconut Water ◽  
Last Stage

Any bioassay to test new chemically synthesized larvicides or phytolarvicides against Culicidae and more harmful mosquito species, such as Aedes aegypti and Aedes albopictus, which specifically transmit dengue, yellow fever, chikungunya viral fevers as well as Zika virus, or Anopheles gambiae, a vector for malaria and philariasis, requires thousands of well-developed larvae, preferably at the fourth instar stage. The natural morphogenetic cycle of Aedes spp., in the field or in the laboratory, may extend to 19 days at room temperature (e.g., 25°C) from the first permanent contact between viable eggs and water and the last stage of larval growth or metamorphosis into flying adults. Thus, accelerated sequential molting is desirable for swifter bioassays of larvicides. We achieved this goal in Aedes aegypti with very limited strategic and low-cost additions to food, such as coconut water, milk or its casein, yeast extract, and to a lesser extent, glycerol. The naturally rich coconut water was excellent for quickly attaining the population of instar IV larvae, the most advanced one before pupation, saving about a week, for subsequent larvicidal bioassays. Diluted milk, as another food source, allowed an even faster final ecdysis and adults are useful for mosquito taxonomical purpose.

Palaeoenvironment and agriculture of ancient Loulan and Milan on the Silk Road

The Holocene ◽  
2012 ◽  
Vol 23 (2) ◽  
pp. 208-217 ◽  
Author(s):  
Jianping Zhang ◽  
Houyuan Lu ◽  
Naiqin Wu ◽  
Xiaoguang Qin ◽  
Luo Wang
Keyword(s):  
Food Source ◽  
Foxtail Millet ◽  
Silk Road ◽  
Ancient Lake ◽  
Naked Barley ◽  
Main Food Source ◽  
Staple Crop ◽  
The City ◽  
Lop Nor ◽  
The Silk Road

Ancient Loulan, an important city on the Silk Road, disappeared about 1500 years ago. The environmental conditions associated with the vicissitude of ancient Loulan have been debated since the city was rediscovered in ad 1900. However, little paleobotanical evidence concerning vegetation and environment in this area has so far been available. In this study, phytoliths and diatoms extracted from 16 samples including two fossil camel coprolites from sites of Loulan and Milan indicate that the landscape of ancient Loulan was a typical oasis, where reeds, grasses of Paniceae and Pooideae probably grew along with some shrubs. Also, some typical brackish diatoms might live in some water bodies in the catchment of an ancient lake, Lop Nor. Our results also suggest that common millet as staple crop, and foxtail millet and possibly naked barley as non-staple crops were the main food source for ancient Loulan and Milan residents between ad 50 and 770.

scholarly journals Potensi dan Kendala Kebijakan Perlindungan Lahan Pertanian Pangan Berkelanjutan di Kabupaten Demak

2012 ◽  
Vol 8 (2) ◽  
pp. 157
Author(s):  
Meirina Rokhmah
Keyword(s):  
Land Use ◽  
Food Source ◽  
Actual Condition ◽  
Land Conversion ◽  
High Demand ◽  
Farm Land ◽  
Land Protection ◽  
Factors Affecting ◽  
Land Use Conversion ◽  
Main Food Source

Perlindungan Lahan Pertanian Pangan Berkelanjutan (PLP2B ‐ Sustainable Farm Land Protection) is agovernment policy aimed to prevent farm land conversion. It has been implemented among others inDemak Regency, which is one of the region’s main food source. The study identified the potential andchallenges of the implementation of the policy through the method of superimpose between the plannedmap and the actual land use conversion, supported by land conversion data from the Land Office andinterview with selected sources. The study showed that land conversion is still occurring and that thereare mismatches between the planned map and the actual condition. Interviews suggested that there stillvast measure of farm land available still for improvement into sustainable farm lands. Challenges emergefrom the high demand for housing areas, illegal land conversion and lack of policy socialization to thecommunity.Keywords: land conversion, planning map, factors affecting the implementation of policy

WEIGHT AND DEVELOPMENT TIME OF DIFFERENT STADIA OF MOSQUITOES REARED AT VARIOUS CONSTANT TEMPERATURES

1967 ◽  
Vol 99 (9) ◽  
pp. 986-993 ◽  
Author(s):  
R. A. Brust
Keyword(s):  
Weight Gain ◽  
Development Time ◽  
Adult Stage ◽  
Larval Instar ◽  
Dry Weight ◽  
Specific Weight ◽  
Fourth Instar ◽  
Rearing Temperature ◽  
Males And Females ◽  
Culiseta Inornata

AbstractDevelopment time decreased with each increase in rearing temperature in Aedes vexans, A. nigromaculis, and Culiseta inornata until the optimum survival temperature was reached. The optimum survival temperature for A. vexans was 26.5 °C, for A. nigromaculis 21 °C, and for C. inornata 21 °C. Dry weight gain per hour in female larvae was greater than in male larvae in all three species, at all temperatures. There was a significant reduction in weight in each larval instar, pupal, and adult stage, with each 5.5 °C increase in rearing temperature. Times to larval–pupal ecdysis and pupal–adult ecdysis were the same for males and females of A. nigromaculis at all developmental temperatures tested. Time to larval–pupal ecdysis and pupal–adult ecdysis in A. vexans and C. inornata occurred 1 to several days later in females, depending upon the developmental temperature. In all three species the duration of the fourth instar was longest and the specific weight gain greatest.

Palaeoecology of the marine reptiles of the Redwater Shale Member of the Sundance Formation (Jurassic) of central Wyoming, USA

2013 ◽  
Vol 151 (1) ◽  
pp. 167-182 ◽  
Author(s):  
JUDY A. MASSARE ◽  
WILLIAM R. WAHL ◽  
MIKE ROSS ◽  
MELISSA V. CONNELY
Keyword(s):  
Primary Productivity ◽  
Food Source ◽  
Foreland Basin ◽  
Gut Contents ◽  
Ecological Diversity ◽  
Marine Transgression ◽  
The North ◽  
Marine Reptiles ◽  
Main Food Source ◽  
Clay Formation

AbstractThe Redwater Shale Member (Oxfordian) of the Sundance Formation was deposited in the foreland basin of the Cordillera during the last and largest marine transgression of the Jurassic in North America. One ichthyosaur (Ophthalmosaurus natans), two cryptocleidoid plesiosaurs (Tatenectes laramiensis, Pantosaurus striatus) and one pliosauromorph (Megalneusaurus rex) are known from the Redwater Shale Member. Ichthyosaurs are much more abundant than plesiosaurs, making up almost 60% of the fauna. No actinopterygian fish have been found, although four species have been identified from the lower Sundance Formation. At least one hybodont shark and one neoselachian are known from rare isolated teeth. The main food source for the marine reptiles was belemnoids, as indicated by preserved gut contents for all four species. In comparison, the better known and slightly older Peterborough Member of the Oxford Clay Formation of England, has a much higher taxonomic and ecological diversity, especially in the plesiosaurs, marine crocodiles, and fish. The lower diversity in the Redwater Shale Member probably reflects a much lower primary productivity in the Sundance Sea, as well as restricted migration from the open ocean to the north.

scholarly journals The benthos: the ocean’s last boundary?

2020 ◽  
Vol 84 (4) ◽  
pp. 463-475
Author(s):  
Josep-Maria Gili ◽  
Begoña Vendrell-Simón ◽  
Wolf Arntz ◽  
Francesc Sabater ◽  
Joandomènec Ros
Keyword(s):  
Water Column ◽  
Residence Time ◽  
Food Source ◽  
Benthic Communities ◽  
Strong Impact ◽  
Benthic Organisms ◽  
Main Food ◽  
Sinking Particles ◽  
Main Food Source

Benthic communities depend on receiving much of their food from the water column. While sinking, particles are transformed in a discontinuous process and are temporally retained in transitional physical structures, which act as boundaries and contribute to their further transformation. Motile organisms are well-acquainted with boundaries. The number, width and placement of boundaries are related to the degree of particle degradation or transformation. Progressively deepening within each boundary, particles are degraded according to their residence time in the discontinuity and the activity of the organisms temporarily inhabiting that boundary. Finally, particles reach the seafloor and represent the main food source for benthic organisms; the quality and quantity of this food have a strong impact on the development of benthic communities. However, benthic communities not only play the role of a sink of matter: they act as an active boundary comparable to other oceanic boundaries, in accordance with the boundary concept proposed by the ecologist Ramon Margalef.

scholarly journals Levels of Elements in Typical Mussels from the Southern Coast of Africa (Namibia, South Africa, Mozambique): Safety Aspect

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3238
Author(s):  
Pavel Nekhoroshkov ◽  
Jacques Bezuidenhout ◽  
Inga Zinicovscaia ◽  
Nikita Yushin ◽  
Konstantin Vergel ◽  
...  
Keyword(s):  
South Africa ◽  
Food Source ◽  
Mytilus Galloprovincialis ◽  
Soft Tissues ◽  
Hazard Indices ◽  
The West ◽  
Calculated Risk ◽  
Permissible Levels ◽  
Main Food Source ◽  
Richards Bay

The soft tissues of mussels are often used as the main food source, especially in coastal areas. Neutron Activation Analysis was used to measure the content of 24 macro- and microelements in the soft tissues and 18 elements in the shells of selected sets of mussels of the species Mytilus galloprovincialis. The mussels were collected in 8 polluted and 4 pristine zones, which included Namibia, the west and east coasts of South Africa, and Mozambique. According to factor analysis Co, Ni, Zn, As, Se, Br, I, Sb could have anthropogenic origin. The concentrations of elements such as Cr, As, Se and partly Zn at polluted stations were above the maximum permissible levels for seafood. The concentrations of Sc, V, Cr, Mn, Co, Ni, Sb, Cs, Th, U in shells and soft tissues of the same mussels were at the close levels. Elements such as Al, Cr, Co, As (partly Zn, Se, and I) are considered to be harmful to human health at the levels of mussels consumption of 200 g/week per person and lower in such zones as Swakopmund, East London, Port Shepstone, Richards Bay, Xai-Xai according to calculated risk quotients and target hazard indices.

scholarly journals The effect of abiotic and biotic factors on the importance of macroplankton in the diet of Northeast Arctic cod in recent years

2005 ◽  
Vol 62 (7) ◽  
pp. 1463-1474 ◽  
Author(s):  
E.L. Orlova ◽  
A.V. Dolgov ◽  
G.B. Rudneva ◽  
V.N. Nesterova
Keyword(s):  
Energy Balance ◽  
Food Source ◽  
Water Mass ◽  
Ecological Groups ◽  
Biotic Factors ◽  
Low Fat ◽  
Main Food ◽  
Different Types ◽  
Abiotic And Biotic Factors ◽  
Main Food Source

AbstractUsing cod feeding data, this paper considers the distribution and abundance of macroplankton from different ecological groups (euphausiids and hyperiids) and the variability in their consumption by cod over a period of years during which different water mass temperatures were observed. These years were also characterized by variable abundance of capelin, cod's main food source. Differences in intensity and duration of cod consumption of euphausiids and hyperiids species are shown, depending on their abundance, temperature conditions, cod distribution, and the supply of capelin for cod. This paper discusses the energetics of consuming different types of prey and the role euphausiids play in the energy balance of cod. The low fat content of cod is sometimes associated with feeding on postspawning euphausiids in summer and autumn.

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