Adults Of Rhyzopertha Dominica Research Articles

Fluorescent Pigments for Marking Lesser Grain Borers (Coleoptera: Bostrichidae)

Fluorescent dyed melamine copolymer resins were evaluated to determine their effectiveness for marking adult Rhyzopertha dominica to be used in release-recapture experiments. Pigments were retained very well, and marked individuals were easily identified under longwave ultraviolet light up to 21 d after treatment. Little pigment was transferred between individuals during mating or other contact within a bulk of wheat. Treatment with fluorescent pigment did not reduce fecundity or prevent flight activity.

Distribution Patterns of Lesser Grain Borer (Coleoptera: Bostrichidae) in Towers of Wheat, and Effects of the Presence of the Granary Weevil (Coleoptera: Curculionidae)

Adult Rhyzopertha dominica (F.) and Sitophilus granaries (L.) were introduced into the tops of six towers (1.7–2.6 m high) filled with wheat. Samples removed two, three, and four months later revealed that <1.0% of R. dominica and S. granarius were found below 127 cm and 63 cm, respectively. Low population densities of S. granarius precluded detennination of distribution patterns, but the damage caused by S. granarius apparently affected the distribution patterns of R. dominica . The distribution patterns of adult and immature R. dominica differed.

Sexing live adult Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae)

A recently published method of sexing live adult Rhyzopertha dominica (F.) using a punctuate groove on the fifth abdominal sternite of the males was found unsatisfactory for the strains from Queensland, Australia. Detailed assessment was made of the squeezing and colour methods of sexing live adult beetles. Squeezed virgin females subsequently mated to untreated males had a reduced fecundity. Untreated females mated to squeezed males also produced fewer eggs than the control although the mating ability of squeezed males was not significantly affected by the treatment. Squeezing significantly reduced the life expectancy but not of males. One observer caused more damage than the other. In colour sexing a greater accuracy was achieved by avoiding difficult choices. Egg production of females with strong colour marking was not significantly lower than that of unselected females.

Resistance of Polymer Films to Penetration by Lesser Grain Borer and Description of a Device for Measuring Resistance13

In tests with a newly developed laboratory device for determining the resistance to penetration of flexible packaging films by adults of Rhyzopertha dominica (F.), polyurethane and polyester films were the most resistant of 18 types tested. Polypropylene and fluorinated carbon polymer films varied in resistance to penetration. Plasticized polyvinyl chloride, ionomer, cellulose propionate, polyvinyl alcohol, saran, and polyethylene-ethylene vinyl acetate copolymer films were susceptible to penetration, as were 7 types of cellophanes.

A reliable character for sexing live or dead Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

A new, reliable character is described and illustrated for distinguishing the sexes in adult Rhyzopertha dominica (F.). Both live and dead beetles can be sexed accurately using the method.

The effect of phosphine on respiration and mitochondrial oxidation in susceptible and resistant strains of Rhyzopertha dominica

Phosphine, (hydrogen phosphide), decreased the respiration of Rhyzopertha dominica adults, susceptible to the fumigant but had little effect on that of a strain selected for its resistance to this gas. Inhibition of mitochondrial oxidation by phosphine in vitro was similar in both strains. The implications of these findings with respect to mechanisms of resistance to the fumigant are discussed.

COLD TOLERANCE IN RELATION TO STARVATION OF ADULT RHYZOPERTHA DOMINICA (COLEOPTERA: BOSTRICHIDAE)

AbstractThe tolerance of young adult Rhyzopertha dominica (Fab) to sub-freezing temperatures, −5, −10, −12, −18, −21, and −25 °C, was studied. Mortality in test populations increased in proportion to amplification of both intensity and duration. The increase in mortality with respect to duration follows a sigmoid curve. Environmental stresses, i.e., intense cold and starvation, increase the slope of the curve. In all cases, starvation mitigates against survival. R. dominica dies of starvation in a period between 116 and 432 h. Mortality due to starvation plotted against time yields a sigmoid curve.Inhibition in feeding was observed in starved populations after 20 min of exposure at −18 °C or lower. This inhibition led to death after 7 days and apparently occurred secondarily to a state of “stress-induced lethargy.” Stress-induced lethargy was observed only in organisms which were both starved and subjected to sub-freezing temperatures.

Gamma, infra-red and microwave radiation combinations for control of Rhyzopertha dominica in wheat

Samples of soft winter wheat containing eggs, larvae, pupae, or adults of Rhyzopertha dominica (F.) were given one of the following treatments: (1) Gamma radiation; (2) infra-red radiation; (3) microwave radiation; (4) gamma + infra-red; or (5) gamma + microwave. The percentage of adult emergence from treated immatures or the mortality and fecundity of treated adults provided a basis for evaluating the effectiveness of the treatments. The average reductions in emergence were 54, 55, and 42 per cent for gamma, infra-red, and microwave treatments, respectively. The reductions in emergence averaged 99 per cent for the gamma + infra-red combination and 96 per cent for the gamma + microwave combination. These mortalities were about 20 per cent higher than predicted. Adult mortality data were inconclusive because of the very low gamma dosage used. However, reductions in adult fecundity for the above combinations were about 95 and 89 per cent, respectively. These were about 22 and 9 per cent greater than the predicted reductions in fecundity.

Effects of Gamma Rays on the Acute Lethality and Reproductive Potential of Lesser Grain Borer Adults1

The acute lethality and reproductive potential of one week-old adult Rhyzopertha dominica (F.) were determined at various exposures ranging between 5 and 320 kR of gamma rays. Observations revealed that exposure of 320 kR killed all the beetles during irradiation. Treatments of 20 kR or greater produced 100% mortality within 4-25 days, depending on the exposure. Beetles surviving the 5 kR exposure for the 1st 30-day-post treatment period lived as long as the controls. The exposure of 5 kR or greater resulted in the permanent sterility of both sexes of the beetles. Practical and radiobiological implications of the findings are discussed.

Air-tight storage of grain; its effect on insect pests—IV Rhyzopertha dominica (F.) and some other Coleoptera that infest stored grain

The independent effects of reduced oxygen tensions and increased carbon dioxide tensions on the mortality of adults of Rhyzopertha dominica (F.), Tribolium castaneum (Hbst.), Oryzaephilus surinamensis (L.) and Cryptolestes ferrugineus (Steph.) and the larvae of Trogoderma granarium Everts have been examined. Their apparent respiratory quotients under air-tight conditions have been measured by following the changes occurring in the air among grain infested by each of the species. It is demonstrated that the five species of insects are killed by oxygen depletion and not by the accumulation of carbon dioxide.