Author: Ruth Pettinga O'NeillPublisher:
ISBN:
Category : Alfalfa leafcutting bee
Languages : en
Pages : 138
Book Description
Seasonal and Spatial Patterns of Mortality and Sex Ratio in the Alfalfa Leafcutting Bee, Megachile Rotundata (F.)
Author: Ruth Pettinga O'NeillPublisher:
ISBN:
Category : Alfalfa leafcutting bee
Languages : en
Pages : 138
Book Description
Sexual Conflict in the Alfalfa Leafcutting Bee, Megachile Rotundata, and the Effect of the Haplodiploid Genetic System
Author: Benjamin Howard RossiPublisher:
ISBN:
Category :
Languages : en
Pages : 326
Book Description
Population Dynamics of Larvae of Alfalfa Leafcutting Bee, Megachile Rotundata, in Eastern Washington
Author: Jack D. EvesPublisher:
ISBN:
Category : Agriculture
Languages : en
Pages : 30
Book Description
Alfalfa Leafcutting Bee
Author: Michael John BrewerPublisher:
ISBN:
Category : Alfalfa leafcutting bee
Languages : en
Pages : 4
Book Description
Effects of Temperature and Other Abiotic and Biotic Factors on Development and Survival of the Immature Stages of the Alfalfa Leafcutting Bee, Megachile Pacifica (Panzer) (
Author: Jaime M. Undurraga O.Publisher:
ISBN:
Category : Alfalfa leafcutting bee
Languages : en
Pages : 438
Book Description
Larval mortality of leafcutting bee, Megachile pacifica (Panzer) (= rotundata (F.)), is high, usually exceeding 50%. Parasites and predators are not a limiting factor in the survival of the progeny. The disease chalk brood has been an important mortality factor since 1974. Inadequate food supply, pollen and nectar, may affect the survival of the progeny. Genetic differences within and between populations and the saponin content of alfalfa leaves do not affect brood production or survival. Domicile design and protection may also have a great influence on survival. Temperatures exceeding 50°C occur in cells when nesting material receives direct sunlight or when nesting material is housed in domiciles with poor ventilation and insulation. There are temperature differences between cells in a series, between nest positions within a domicile, and between types of nesting materials. There is no direct relationship between ambient and cell temperatures because the latter are influenced by exposure, nesting media, placement, and domicile structure. High internal bee body temperatures may occur during most bee activities, excluding resting. The effects of high temperatures on the adult bee or the eggs she contains are not known. Although larval development can proceed at temperatures below 21°C, survival is reduced. Adult activity, like metabolic larval development, can be conditioned to unusually high or low temperatures; thus, there is no absolute temperature threshold for development or activity in this bee. Eggs and young larvae reared at a constant 30°C had over 85% survival, in most years. An ambient temperature of 45°C applied for one to three hours resulted in a higher mortality of eggs and early instars than the control temperature of 30°C; at 50°C, mortality was complete. Exceptions were obtained for either situation. Half hour exposure at 50°C ambient temperature was also detrimental to immatures. An ambient temperature of 40°C in general does not affect survival of immatures. In-cell temperatures were at least 5°C lower than ambient temperatures in incubators during treatments. Repeating heat treatments on two or more days was not as severe as the duration of treatments. Larvae showed heat tolerance when exposed to two to three hours at 45°C but not to one hour, but some exceptions occurred. The mechanism for heat tolerance is not well understood, and may be related to a conditioning of individuals to high temperatures. A seasonal effect on survival was obtained and appears not to be related to the age of the laying females, nor to the generations, but rather to the thermal history to which the immatures were exposed. Heat susceptibility of eggs and early instars seemed to be similar. Fourth and fifth instars were the most heat tolerant of all larval stages. Exposure of young larvae to low temperatures before they were exposed to high temperatures did not increase mortality. However, sublethal high temperatures were generally less harmful to the immatures that were conditioned but this acclimation of the larvae did not occur in every test. Upper threshold temperature limits cannot be precisely defined, nevertheless, cell temperatures over 40°C result in egg and larval mortality. Brief exposure to 45°C was the upper limit that developing pupae could tolerate; 50°C was lethal. Pupae were most heat sensitive between three and six days before emergence. When exposed to high temperatures, pupae and emerging adults were able to arrest development. Pupae and emerging adults can be conditioned to tolerate short exposures to lethal temperatures up to seven days before emergence. Low temperatures did not affect the survival of pupae. Development of pupae and emerging adults could be arrested for up to a week at 15.6°C without harmful effect. Development and emergence proceed at 21 °C, but pupae need at least 2.5 hours per day of temperatures above 21°C to survive when not in an arrested state. Pupae not exposed to temperature above 29°C during 24 hours, emerged normally. Incubation at 29.5°C for less than 10 hours per day delayed the emergence. Pupae maintained at 15.6 °C for 22 hours per day for 8 days or for 20 hours per day for 16 days emerged after a delay longer than the period of cold. Cooling the emerging bees after high temperature treatment appeared to be more detrimental than cooling before exposures to high temperatures. The detrimental effect of extreme temperatures was shown on the survival of eggs, young larvae, and pupae, but possible chronic effects on later stadia were not studied.
Alfalfa Leaf-cutting Bee Megachile Rotundata F. (
Author: Bozhana DochkovaSome Factors that Affect Pollination and Seed Formation in Alfalfa, Medicago Sativa L
Author: Norman Richard BradnerPublisher:
ISBN:
Category : Alfalfa
Languages : en
Pages : 148
Book Description
The objectives of this study were (a) to measure the amount of cross-pollination caused by three bee species at 10, 20 and 40 rods distance from a foreign pollen source, (b) to measure the effects of bee species, planting pattern and season on broad sense heritability estimates for seed yield in alfalfa, (c) to determine the incidence of selfing caused by the bees, (d) to investigate the usefulness of bees as a breeding tool in alfalfa and (e) to determine which of the three planting patterns used in this investigation is the best in effecting the maximum amount of cross-pollination. Three bee species, the honey bee, Apis mellifera L.; the leaf-cutter bee, Megachile rotundata F. and the alkali bee, Nomia melanderi Ckll. were chosen for this investigation because of their importance as pollinators in alfalfa. Studies under conditions of good isolation for bee species and competitive bloom were necessary to obtain reliable results. In the center of a three mile square isolated area, seven plots of recessive white-flowered clonally established plants were planted 10, 20, 40, 80, 160, 240 and 320 rods north of a colored-flowered population, and seven plots were planted at the same distance east of the colored-flowered population. Seven planting patterns were used in the east series. Three of these were utilized by the bees described. The number of florets tripped, pods developed and seeds developed in each pod were recorded for each raceme visited by pollen collecting bees. Seed samples from the white-flowered clones were grown in a greenhouse to ascertain whether the seed resulted from cross- or self-pollination. A record of flower color in 1963 demonstrated that at 10, 20 and 40 rods from a contaminant source honey bees caused 15.7, 11.2 and 5.8 percent cross-pollination; leaf-cutter bees caused 13.1, 4.8 and 8.1 percent cross-pollination while endemic pollinators caused 42.9, 30.9 and 10.0 percent cross-pollination in 1962. An important fact in this regard was that endemic pollinators caused 6.52 percent cross-pollination at a distance of a mile. Bee species, planting pattern and season caused large fluctuations in broad sense heritability estimates for seed yield in alfalfa. The ratio environmental variance to phenotypic variance gave a good indication which environmental factor caused the most fluctuation in the estimate. When endemic pollinators were used 94.7, 88.3, 36.3 and 23.1 percent selfed seeds were recorded as occurring in pods with one, two, three and four or more seeds per pod. One seven seeded pod was recorded as possessing three selfed seeds. Data from leaf-cutter bees showed that all of the pod types had over 67 percent selfed seeds. Distance from the contaminant source affected the percentage selfed seeds. At 40 rods only the four or more seeded pods contained any crossed seeds (20 percent) Leaf-cutter bees trip 27-50 percent more florets per raceme and cause less cross-pollination at 10, 20 and 40 rods than honey bees. Honey bees cause approximately the same amount of cross-pollination at 10 and 20 rods while the value obtained at 20 rods for the leaf-cutter bee was close to one-third of the value at 10 rods. Leaf-cutter bees also showed less preference between colored- and white-flowered alfalfa flowers. Of several planting patterns considered, maximum cross-pollination was obtained in a plot planted with alternating rows of alfalfa.
The Potential of the Alfalfa Leafcutter Bee Megachile Rotundata Fabr. (Hymenoptera: Megachilidae) as a Pollinator of Lowbush Blueberry (Vaccinium Angustifolium Ait., V. Myrtilloides Michx.) [microform]
![The Potential of the Alfalfa Leafcutter Bee Megachile Rotundata Fabr. (Hymenoptera: Megachilidae) as a Pollinator of Lowbush Blueberry (Vaccinium Angustifolium Ait., V. Myrtilloides Michx.) [microform] PDF](https://books.google.com/books/content/images/frontcover/a3P1jgEACAAJ?fife=w80-h100)
Author: Steven Karel JavorekPublisher: National Library of Canada = Bibliothèque nationale du Canada
ISBN: 9780612160606
Category : Alfalfa leafcutting bee
Languages : en
Pages : 170
Book Description
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