ECOLOGY OF STORED GRAIN IN THE CANADIAN PRAIRIES: I. THE DISTRIBUTION AND SIZE OF A LOW DENSITY POPULATION OF CRYPTOLESTES FERRUGINEUS (COLEOPTERA: CUCUJIDAE)

1978 ◽  
Vol 110 (12) ◽  
pp. 1281-1292 ◽  
Author(s):  
L. B. Smith
Keyword(s):  
Biological Activity ◽  
Moisture Content ◽  
First Year ◽  
Low Density ◽  
Cryptolestes Ferrugineus ◽  
Stored Grain ◽  
Canadian Prairies ◽  
Storage Density ◽  
Insect Density ◽  
Density Population

AbstractTwo metal granaries each containing 27.3 tonnes of dry wheat (13–14% m.c.) were artificially infested with Cryptolestes ferrugineus (Stephens) and sampled for up to 4 years to determine fluctuations in insect density as influenced by changes in grain temperature and moisture content during storage. Density remained low (fewer than 5 insects/kg) throughout the period of study. Most insects were found at the floor near the wall on the south side of the granary. The temperature in the centre of the grain mass ranged from −5° to 22 °C during the 4 years. During a single season, moisture content varied as much as 5% at the centre near the surface of each grain mass, but did not vary more than 1% at other locations. In the first year of storage, the viability of the wheat ranged from 80% to 96%, and after 3 years in storage, 68% to 100%. Since no significant change was recorded in the temperature, moisture content, or germination of the wheat in the granaries, it was concluded that the biological activity of a low density population of C. ferrugineus does not initiate heating that occasionally occurs in farm-stored grain in Canada.

scholarly journals Intra- and interspecific interactions among Tribolium castaneum and Cryptolestes ferrugineus in stored wheat at different insect densities

2004 ◽  
Vol 84 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Raj B. Hulasare ◽  
Noel D.G. White ◽  
Digvir S. Jayas ◽  
Colin J. Demianyk
Keyword(s):  
Moisture Content ◽  
Tribolium Castaneum ◽  
Interspecific Interactions ◽  
Adult Population ◽  
Single Species ◽  
Cryptolestes Ferrugineus ◽  
Stored Grain ◽  
Hard Red Spring Wheat ◽  
Species Combination ◽  
Insect Density

Summary Cryptolestes ferrugineus and Tribolium castaneum are important economical pests of stored grain in Canada. Insects were reared separately or together on hard red spring wheat at three insect densities representing 1000, 500, and 250 adults per kilogram of wheat for single species and twice that of single densities for mixed species, in the laboratory (30°C, 70% RH). The experiment was conducted on dry (12% moisture content [MC], wet basis) and damp wheat (15% MC, wet basis). Adults were sampled every 2 weeks over a 10-week period. Sifted wheat was incubated at 30°C, 70% RH for 4 weeks to observe the number of adults emerging from immatures present under the seed coat of the wheat germ. All experiments were replicated four times. Initial insect densities, moisture content, and species combination had significant effects on the resulting adult population. Adult numbers for both species were higher on 15% MC wheat. In 12% MC wheat, T. castaneum numbers were higher than C. ferrugineus numbers when reared separately whereas this was reversed in 15% MC grain. Cryptolestes ferrugineus populations were significantly higher when reared with T. castaneum than when reared as a single species on 12% MC grain. The trend was reversed in 15% MC grain. At both grain moistures, T. castaneum numbers were higher as an isolated species compared to when reared with C. ferrugineus. The study suggested that T. castaneum populations were inhibited in the presence of C. ferrugineus. High insect density often accentuated these effects.

The natural regulation of giant tortoise populations on Aldabra Atoll: recruitment

1979 ◽  
Vol 286 (1011) ◽  
pp. 177-188 ◽  
Keyword(s):  
High Density ◽  
Annual Rainfall ◽  
Egg Mass ◽  
First Year ◽  
Low Density ◽  
Isolated Populations ◽  
High Density Population ◽  
Density Area ◽  
Low Density Area ◽  
Density Population

The reproductive ecology of the giant tortoise ( Geochelone gigantea Schweigger) in three isolated populations was studied for 2 years on Aldabra Atoll. Density-dependent recruitment was demonstrated. Nest destruction in the low density area was dependent on the density of mature females providing a mechanism for regulating population size. Increases in annual rainfall and the resultant increase in food availability induced an increase in mean egg mass in the low density area (and thereby total hatchling production), whereas in the high density population mean clutch size, mean egg mass, total number of nests and total hatchling production all increased significantly. Large eggs produced large hatchlings which survived better during the first year than hatchlings from small eggs. Hatchling mortality was 94 and 81 % in the first year in the high and low density populations respectively. Recruitment into the 5 year age class (after which predation is considered negligible) had almost ceased in the high density population compared with 0.44 per 100 breeding females per year in the low density population.

scholarly journals Effectiveness of carbon dioxide in compressed gas or solid formulation for the control of insects and mites in stored wheat and barley

2005 ◽  
Vol 74 (2) ◽  
pp. 101-111 ◽  
Author(s):  
N.D.G. White ◽  
D.S. Jayas
Keyword(s):  
Carbon Dioxide ◽  
Triticum Aestivum ◽  
Hordeum Vulgare ◽  
Seed Germination ◽  
Moisture Content ◽  
Tribolium Castaneum ◽  
Cryptolestes Ferrugineus ◽  
Stored Grain ◽  
Compressed Gas ◽  
Grain Bulks

Carbon dioxide can be used as an effective stored-grain fumigant in relatively air-tight bins. Carbon dioxide was added to wheat (Triticum aestivum) as a compressed gas and to barley (Hordeum vulgare) as a solid (dry ice) in 322-kg grain bulks. Wheat was stored at temperature decreasing from 18 to 10°C over a 12-wk period. Bins were left open, sealed without C02 added, or with C02 supplemented at 25,34, and 46% levels. Barley was stored at temperature decreasing from 25 to 20°C over an 8-wk period. Bins were left open, sealed without C02 added, or with C02 treatments of 23, 29, and 34%. The wheat and barley moisture content were 14.5-16.3% and 14.5-16.1%, respectively. Oxygen levels in the wheat reflected air displacement with C02, but lower O2 levels in the barley reflected a combination of air displacement by C02 and consumption of O2 by respiring grain and microorganisms at the warmer temperatures. The insects Cryptolestes ferrugineus and Tribolium castaneum were controlled in 2 wk at 34% C02 and 15% O2 at temperature decreasing from 18 to 10°C, or 29% C02 and 3% O2 at temperature decreasing from 25 to 20°C. The mites Tarsonemus granarius, Lepidoglyphus destructor, and Aeroglyphus robustus were killed in less than 2 wk at these C02 levels. Seed germination and microflora were unaffected by all gaseous environments.

Effects of Moisture Content and Initial Insect Density on Ability of Rusty Grain Beetles (Coleoptera: Cucujidae) To Infest Whole Corn2

1990 ◽  
Vol 25 (1) ◽  
pp. 25-29 ◽  
Author(s):  
James E. Throne
Keyword(s):  
Zea Mays ◽  
Moisture Content ◽  
Seed Coat ◽  
Zea Mays L ◽  
Cryptolestes Ferrugineus ◽  
Progeny Production ◽  
Moisture Contents ◽  
Grain Beetles ◽  
Insect Density ◽  
Corn Kernels

Rusty grain beetle (RGB), Cryptolestes ferrugineus (Stephens), progeny production on undamaged corn kernels (Zea mays L.) and on artificially damaged kernels was investigated at varying moisture contents and initial insect densities. Only three adult progeny were produced on undamaged kernels in both tests. The number of adult progeny produced on damaged kernels increased as moisture content increased from 11.3 to 14.8%, but was still low. Initial insect densities of 1, 2, 5, 10, 20, or 40 RGB on ten kernels of corn did not affect the low number of progeny produced on damaged kernels. These results indicate that even though a high proportion of stored corn contains breaks in the seed coat, growth of RGB populations would be slow if the corn is otherwise intact and is stored at or below 14.8% moisture content.

scholarly journals Ability of Spalangia endius (Hymenoptera: Pteromalidae) to Parasitize Bactrocera dorsalis (Diptera: Tephritidae) after Switching Hosts

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 613
Author(s):  
Yuan Zheng ◽  
Zi-Wei Song ◽  
Yu-Ping Zhang ◽  
Dun-Song Li
Keyword(s):  
Bactrocera Dorsalis ◽  
Low Density ◽  
Type Ii ◽  
Emergence Time ◽  
Functional Responses ◽  
Parasitism Rate ◽  
Spalangia Endius ◽  
Pupal Parasite ◽  
Density Population

We studied the parasitism capacity of Spalangia endius as a pupal parasite of Bactocera dorsalis after switching hosts. We used pupae of B. dorsalis and M. domestica as the hosts and studied parasitism by S. endius in the laboratory. The parasitism capacities were compared at different host densities and different parasitoid ages. The two functional responses of S. endius fitted a Holling Type II equation. More M. domestica were parasitized than B. dorsalis at all the densities. The ability of S. endius to control M. domestica was α/Th (parasitism capacity) = 32.1950, which was much stronger than that of control B. dorsalis, which was α/Th = 4.7380. The parasitism rate of wasps that had parasitized B. dorsalis had decreased by the emergence time of parasitoids. These results suggest that the parasitoid-pest ratio should be 1:25 to maintain a relatively stable parasitism rate for control of B. dorsalis. The S. endius colony reared on M. domestica successfully controlled a low-density population of B. dorsalis in the lab. We provide evidence suggesting that the parasitism capacity of S. endius needs to be improved.

STORABILITY OF FARM-STORED HULLESS OATS IN MANITOBA

1979 ◽  
Vol 59 (4) ◽  
pp. 949-957 ◽  
Author(s):  
R. N. SINHA ◽  
H. A. H. WALLACE ◽  
J. T. MILLS ◽  
R. I. H. McKENZIE
Keyword(s):  
Storage Temperature ◽  
First Year ◽  
Aspergillus Versicolor ◽  
Cryptolestes Ferrugineus ◽  
Moisture Contents ◽  
Grain Moisture ◽  
Avena Nuda ◽  
Low Levels ◽  
Second Year ◽  
Temperature Levels

Storability of properly harvested, mature hulless oats (Avena nuda L. ’Terra’) of 9.7–10.5% moisture content was determined from a 24-mo field trial of two 11.5-t lots of oats stored in two wooden farm bins in Manitoba during 1976–78. Oats were stored safely with very low levels of infestation by preharvest fungi, mites and insects and negligible quality loss for up to about 20 mo. Afterwards the grain moisture contents at the bottom layers of both bins rose from about 10 to 13–16%; this led to heavy floor level infestations by the fungi Penicillium and Aspergillus versicolor, and mites Caloglyphus berlesei and Tarsonemus granarius. Fat acidity values rose from the first year levels of about 30 to 50–78 mg KOH/100 g of dry grain. Populations of Cryptolestes ferrugineus and Tribolium castaneum, introduced to one bin, did poorly during the first summer and failed to survive during the second year. A third beetle, Oryzaephilus surinamensis, continued to multiply in small numbers after 22 mo. Low storage temperature levels during most of the years seemed to have affected adversely the multiplication of insects and to a lesser extent mites in farm-stored oats.

scholarly journals A fencing experiment on a high-density population of Microtus townsendii

1977 ◽  
Vol 55 (7) ◽  
pp. 1166-1175 ◽  
Author(s):  
Rudy Boonstra ◽  
Charles J. Krebs
Keyword(s):  
Survival Rate ◽  
Breeding Season ◽  
Population Regulation ◽  
Control Area ◽  
High Density ◽  
Low Density ◽  
Vole Population ◽  
Sharp Decline ◽  
Density Population ◽  
Microtus Townsendii

If dispersal is prevented, a low-density vole population will increase to unusually high densities. A mouse-proof fence was constructed around a vole population that had already reached high density and both this population and one on a control area were live-trapped from January 1975 to November 1975. The population on the control remained at peak densities. The enclosed population increased to even higher density once the breeding season had started and had a higher survival rate than the control population. By midsummer the enclosed population had severely overgrazed the vegetation and went into a sharp decline. Dispersal losses from the control were estimated at 32% for males and 31% for females in these high-density populations. Microtus townsendii populations thus responded to a fence in a manner similar to that of other species that have been studied. This experiment indicates the importance of dispersal to population regulation in voles even at peak densities.

scholarly journals Anatomy and physiology of Cattail as related to different population densities

2015 ◽  
Vol 33 (1) ◽  
pp. 01-12 ◽  
Author(s):  
F.F. CORRÊA ◽  
R.H. MADAIL ◽  
S. BARBOSA ◽  
M.P. PEREIRA ◽  
E.M. CASTRO ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Density ◽  
Root Anatomy ◽  
Low Density ◽  
Typha Angustifolia ◽  
Anatomy And Physiology ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Apoplastic Barriers ◽  
Density Population

The objective of this work was to evaluate the effects of the population density of Typha angustifolia plants in the anatomical and physiological characteristics. Plants were collected from populations of high density (over 50% of colonization capacity) and low density (less than 50% of colonization capacity) and cultivated under controlled greenhouse conditions. Plants from both populations were grown in plastic trays containing 4 L of nutritive solution for 60 days. At the end of this period, the relative growth rate, leaf area ratio, net assimilatory rate, root/shoot ratio, leaf anatomy, root anatomy, and catalase and ascorbate peroxidase activities were evaluated. Plants from high density populations showed increased growth rate and root/shoot ratio. Low density populations showed higher values of stomatal index and density in leaves, as well as increased palisade parenchyma thickness. Root epidermis and exodermis thickness as well as the aerenchyma proportion of high density populations were reduced, these plants also showed increased vascular cylinder proportion. Only catalase activity was modified between the high and low density populations, showing increased values in low density populations. Therefore, different Typha angustifolia plants show differences in its anatomy and physiology related to its origins on high and low density conditions. High density population plants shows increased growth capacity related to lower apoplastic barriers in root and this may be related to increased nutrient uptake capacity.

Effect of Soil Constituents on Herbicide Activity in Modified-Soil Field Plots

Weed Science ◽  
1974 ◽  
Vol 22 (5) ◽  
pp. 454-459 ◽  
Author(s):  
J.B. Weber ◽  
S.B. Weed ◽  
T.W. Waldrep
Keyword(s):  
Organic Matter ◽  
Biological Activity ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Montmorillonite Clay ◽  
First Year ◽  
Herbicide Activity ◽  
Field Plots ◽  
Soil Constituents ◽  
Modified Soil

An organic muck and a montmorillonite clay were incorporated into the surface 7.6 cm of a structureless sandy soil at rates ranging from 26,880 to 89,600 kg/ha. Prometryne [2,4-bis(isopropylamino)-6-(methylthio)-s-triazine] and fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] were surface-applied and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) were incorporated at two rates each in 1968, 1969, and 1970. Organic matter greatly reduced the biological activity of all three herbicides. Montmorillonite clay greatly reduced the activity of prometryne, slightly decreased the activity of fluometuron, and had no significant effect on trifluralin activity in all but the first year of the study. Both soil additives increased the cation exchange capacity of the soil. Muck decreased soil pH while montmorillonite increased it.

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