Populations Of Red Flour Beetle Research Articles

Comparative Efficacy of Madrid Plant Extracts in Controlling Red Flour Beetle Populations: A Laboratory Evaluation of Alcohol and Aqueous Solutions

The efficiency of the alcohol and aqueous excerpt from the Madrid plant in killing ratios of colour red cover beetle larvae and adults afterwards behaviours lasting 24, 48, and 72 hours was valued in laboratory research. Three dissimilar Madrid plant absorptions (1.50 per cent, 3.0%, and 4.59 per cent) were selected to stop the beetle's larvae and adults. The outcomes displayed that the Madrid plant excerpt formed notable degrees. Following 72 hours, the watery excerpt's adult expiry rate was 33.0%, while the alcohol excerpt was 60.0% at 3.0% absorption. After 72 hours, the alcohol excerpt is concentrated larval expiry rate was 71.0% at 3.0% absorption; whereas the watery excerpt's extreme rate was 66.0%. After it derives the phenomena of attraction and repulsion, the paper initiates that the Madrid excerpt in the watery form displayed the maximum level of pull, reaching 9.30% at the absorption of 3.0% after 72 hours, while the repulsion rate was 15.550% at the similar absorption and time. Following 48 hours, the alcohol excerpt of Madrid showed a pull rate of 12.550% at 1.50% concentration. Additionally, following 72 hours, a revulsion rate of 19.80% at 3.0% concentration was realized in adult beetles. The extreme pull rate of the watery excerpt for larvae was 0.00% at all absorptions, and after 72 hours, a comparable revulsion rate of 10.950% was realized at a 4.50% concentration. Also, after 72 hours, the alcohol excerpt displayed a revulsion rate of 19.150% at 3.0% absorption and a pull rate of 0.00% at all concentrations.

Population demographic history and evolutionary rescue: Influence of a bottleneck event.

Rapid environmental change presents a significant challenge to the persistence of natural populations. Rapid adaptation that increases population growth, enabling populations that declined following severe environmental change to grow and avoid extinction, is called evolutionary rescue. Numerous studies have shown that evolutionary rescue can indeed prevent extinction. Here, we extend those results by considering the demographic history of populations. To evaluate how demographic history influences evolutionary rescue, we created 80 populations of red flour beetle, Tribolium castaneum, with three classes of demographic history: diverse populations that did not experience a bottleneck, and populations that experienced either an intermediate or a strong bottleneck. We subjected these populations to a new and challenging environment for six discrete generations and tracked extinction and population size. Populations that did not experience a bottleneck in their demographic history avoided extinction entirely, while more than 20% of populations that experienced an intermediate or strong bottleneck went extinct. Similarly, among the extant populations at the end of the experiment, adaptation increased the growth rate in the novel environment the most for populations that had not experienced a bottleneck in their history. Taken together, these results highlight the importance of considering the demographic history of populations to make useful and effective conservation decisions and management strategies for populations experiencing environmental change that pushes them toward extinction.

The distribution and spread of naturally occurring Medea selfish genetic elements in the United States.

Selfish genetic elements (SGEs) are DNA sequences that are transmitted to viable offspring in greater than Mendelian frequencies. Medea SGEs occur naturally in some populations of red flour beetle (Tribolium castaneum) and are expected to increase in frequency within populations and spread among populations. The large‐scale U.S. distributions of Medea‐4 (M4) had been mapped based on samples from 1993 to 1995. We sampled beetles in 2011–2014 and show that the distribution of M4 in the United States is dynamic and has shifted southward. By using a genetic marker of Medea‐1 (M1), we found five unique geographic clusters with high and low M1 frequencies in a pattern not predicted by microsatellite‐based analysis of population structure. Our results indicate the absence of rigid barriers to Medea spread in the United States, so assessment of what factors have limited its current distribution requires further investigation. There is great interest in using synthetic SGEs, including synthetic Medea, to alter or suppress pest populations, but there is concern about unpredicted spread of these SGEs and potential for populations to become resistant to them. The finding of patchy distributions of Medea elements suggests that released synthetic SGEs cannot always be expected to spread uniformly, especially in target species with limited dispersal.

Synergistic effect of piperonyl butoxide and emamectin benzoate on enzymatic activities in resistant populations of red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae).

Resistance to grain protectants in Tribolium castaneum (Herbst) is a serious threat to international grain trade. Frequent and overdose application of chemical insecticides is becoming a serious health hazard and cause environmental pollution. Resistance management approaches by using various synergists along with novel compounds has become more imperative to increase efficacy of environmentally safe insecticides. We have evaluated piperonyl butoxide (PBO) and emamectin benzoate mixtures for management of resistant field populations of T. castaneum. The collected strains had demonstrated 50 to 200% resistance already developed against emamectin benzoate as compared with deltamethrin susceptible reference strain. The inclusion of PBO along with emamectin significantly reduced this resistance by at least 28% and the LC50 were lowered from 5.12 to 1.9μg/ml with the highest synergism ration of 2.7 in resistant strain. Enzymatic assays clearly demonstrated that the specific activities of catalase and acetylcholinesterases were significantly decreased at an average of 80% and 60%, respectively, when PBO was included as a synergist at 1:2 ratio with emamectin benzoate. The results highlight the mechanism that renders the field population resistant to emamectin benzoate and suggests the synergistic role of piperonyl butoxide as a potent additive in grain protectants for resistance management.

No evidence for short‐term purging benefits of sexual selection in inbred red flour beetle populations

AbstractSexual selection may increase population‐level fitness by facilitating the removal of deleterious mutations with pleiotropic effects on competition for fertilizations as well as other fitness components in both sexes. Under inbreeding, this could promote purging selection, that is the removal of deleterious recessive alleles exposed in homozygotes via matings between closely related individuals. Here, in two independent experiments, we found no evidence for short‐term purging of the inbreeding load from severely bottlenecked populations of red flour beetles, Tribolium castaneum. We hypothesize that sexual selection may have dual effects on purging, corresponding to good‐genes versus compatible‐genes mechanisms. Whereas the former should facilitate the removal of inbreeding load from bottlenecked populations, the latter may actually hamper this process while simultaneously limiting inbreeding depression by preventing the expression of deleterious recessives.

Population growth rate and genetic variability of small and large populations of Red flour beetle (Tribolium castaneum) following multigenerational exposure to copper.

We reared large (1000 individuals) and small (20 individuals) populations of Tribolium castaneum on diet contaminated with copper in order to determine if the size of a population affects its ability to adapt to adverse environmental conditions. After 10 generations, we used microsatellite markers to estimate and subsequently compare the genetic variability of the copper-treated populations with that of the control populations, which were reared on uncontaminated medium. Additionally, we conducted a full cross-factorial experiment which evaluated the effects of 10 generations of "pre-exposure" to copper on a population's fitness in control and copper-contaminated environments. In order to distinguish results potentially arising from genetic adaptation from those due to non-genetic effects associated to parental exposure to copper, we subjected also F11 generation, originating from parents not exposed to copper, to the same cross-factorial experiment. The effects of long-term exposure to copper depended on population size: the growth rates of small populations that were pre-exposed to copper were inhibited compared to those of small populations reared in uncontaminated environments. Large Cu-exposed populations had a higher growth rate in the F10 generation compared to the control groups, while the growth rate of the F11 generation was unaffected by copper exposure history. The only factor that had a significant effect on genetic variability was population size, but this was to be expected given the large difference in the number of individuals between large and small populations. Neither copper contamination nor its interaction with population size affected the number of microsatellite alleles retained in the F10 generation.

How varying pest and trap densities affect Tribolium castaneum capture in pheromone traps

AbstractThe red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is an important insect pest in food processing facilities. Pheromone trapping is frequently used to monitor red flour beetle populations in structures; however, the optimal trap density and the relationship between trap captures and beetle density is not known. Two experiments were performed concurrently in environmentally controlled 30‐m2 walk‐in chambers to determine the relationship between aggregation pheromone trap captures of red flour beetles and beetle and trap number. In one experiment, beetle density was kept constant at 200 individuals per chamber while trap number was varied from 1 to 8, and in the other experiment trap number remained constant at one per chamber while beetle density varied from 20 to 800 individuals. Results indicated that approximately one out of 23 red flour beetles were captured in a trap. Number of beetles captured in traps increased significantly as beetle density increased; however, the proportion of beetles captured remained consistent across beetle densities with a mean of 4.7 ± 0.6% of individuals captured. Trap captures varied significantly with trap placement within experimental chambers, indicating that subtle differences in the trapping environment can influence trap captures. Data suggested that trap densities of 0.07–0.10 m−2 (2–3 traps per chamber) would maximize trap capture, whereas a trap density of 0.13 m−2 (four traps per chamber) would maximize the predictive ability of a trapping equation estimating beetle density from trap captures. Results provide information needed to more thoroughly explore how environmental factors might influence red flour beetle trap capture in the absence of changes in beetle density. Further understanding of these relationships will allow for more accurate assessments of absolute beetle density from pheromone trap capture data.

Efficacy of spinosad and abamectin against different populations of red flour beetle (Tribolium castaneum Herbst) in treated wheat grain

The efficacy of spinosad and abamectin against T. castaneum adults from a laboratory population with normal susceptibility to contact insecticides and against malathion-resistant populations from Nikinci and Jakovo was tested in the laboratory (25?1?C and 60?5% r.h.). The insecticides were applied to 500 g of untreated wheat grain for each of the following application doses: 0.25, 0.5, 1.0, 2.5 and 5.0 mg a.i./kg. After treatment, wheat was divided into three equal subsamples and 50 T. castaneum adults from each of the three test populations were released the next day into jars for each dose. Mortality was evaluated after 7, 14 and 21 days of exposure to treated wheat grain. Generally, higher concentrations and longer exposure periods resulted in higher efficacy of both insecticides, but abamectin was significantly more effective than spinosad against all three tested populations. After 7 days of exposure, mortality did not exceed 30% in any test variant. Fourteen days after treatment with the highest dose (5 mg/kg) of spinosad, mortality was highest (75%) in the laboratory population, while treatment with the same dose of abamectin achieved the highest mortality (58%) in the laboratory and Jakovo populations. After 21 days, spinosad applied at the rate of 5 mg/kg was most effective (97% mortality) in the laboratory population, while 88% efficacy was recorded in Jakovo population and 87% in Nikinci population. Abamectin doses of 2.5 and 5 mg/kg caused high adult mortality of 94-100% in the laboratory and Jakovo populations, and a significantly lower mortality in Nikinci population (75 and 86%, respectively). Statistically significant differences in the efficacy of spinosad, and particularly of abamectin, were detected among the three tested populations, the greatest difference being between the laboratory and Nikinci populations, which clearly indicates that resistance of T. castaneum adults to malathion had a significant influence.

Phosphine Resistance in <I>Tribolium castaneum</I> and <I>Rhyzopertha dominica</I> From Stored Wheat in Oklahoma

Phosphine gas, or hydrogen phosphide (PH3), is the most common insecticide applied to durable stored products worldwide and is routinely used in the United States for treatment of bulk-stored cereal grains and other durable stored products. Research from the late 1980s revealed low frequencies of resistance to various residual grain protectant insecticides and to phosphine in grain insect species collected in Oklahoma. The present work, which used the same previously established discriminating dose bioassays for phosphine toxicity as in the earlier study, evaluated adults of nine different populations of red flour beetle, Tribolium castaneum (Herbst), and five populations of lesser grain borer, Rhyzopertha dominica (F.) collected from different geographic locations in Oklahoma. One additional population for each species was a laboratory susceptible strain. Discriminating dose assays determined eight out of the nine T. castaneum populations, and all five populations of R. dominica, contained phosphine-resistant individuals, and highest resistance frequencies were 94 and 98%, respectively. Dose-response bioassays and logit analyses determined that LC99 values were approximately 3 ppm for susceptible and 377 ppm for resistant T. castaneum, and approximately 2 ppm for susceptible and 3,430 ppm for resistant R. dominica. The most resistant T. castaneum population was 119-fold more resistant than the susceptible strain and the most resistant R. dominica population was over 1,500-fold more resistant. Results suggest a substantial increase in phosphine resistance in these major stored-wheat pests in the past 21 yr, and these levels of resistance to phosphine approach those reported for other stored-grain pest species in other countries.

Efficacy of diatomaceous earth formulations admixed with grain against populations of Tribolium castaneum

The efficacy of diatomaceous earth (DE) to control stored-products Coleoptera on stored grain was examined against several populations of the red flour beetle, Tribolium castaneum (Herbst). Four commercially available DE formulations were tested: INSECTO ®, Perma-Guard™, Protect-It ® and the diatomite used for the production of Dryacide ®, each at six concentrations (100–1000 ppm). A great variation of efficacy was observed among the DE formulations tested. Protect-It at concentrations up to 400 ppm was found to be the most effective formulation to control red flour beetle populations. However, a concentration of 1000 ppm of Protect-It was necessary to control all adults of all populations. Most T. castaneum populations, except one from Ivory Coast (Asm), were more than 90% controlled with INSECTO and Dryacide DE at 600 ppm. At this concentration, about 88% and 22% Asm adults died with INSECTO and Dryacide DE, respectively. Perma-Guard was the least efficient DE formulation to control T. castaneum adults with three populations exhibiting some survival at 1000 ppm. Reduced susceptibility to DE was observed in two populations, Asm and Lab susceptible from Kansas (Lab-S). As neither population had been previously exposed to DE, it is suggested that red flour beetles may naturally vary in susceptibility to DE. In addition, it was found that some populations can be satisfactorily controlled with some DE formulations but not with others.

Increased fecundity of malathion-specific resistant beetles in absence of insecticide pressure.

Despite that resistance frequency is assumed to decline when selective pressure is relaxed, the stability of resistance frequency has been observed in some insects in the absence of insecticide. In the red flour beetle, Tribolium castaneum, the first case of malathion-resistance was reported in the early 1960s. The malathion-specific resistant phenotype has now almost completely replaced the susceptible one in red flour beetle populations. In the present study, several life-history traits that could influence the fitness of the insects were compared between insecticide-susceptible and malathion-specific resistant populations of the red flour beetle. On average, egg fertility and egg-to-adult development time did not differ between susceptible and resistant populations. However, the fecundity of resistant females was greater than that of susceptible ones. Generally, differences in development time between insecticide resistant and susceptible populations are considered as having more effect on fitness than do differences in fecundity. However, the observed increased female fecundity may participate, in combination with the previously observed increased male reproductive success, to the development and the stability of malathion-specific resistance in T. castaneum.

Comparison of (co)variance component estimates in control populations of red flour beetle (Tribolium castaneum) using restricted maximum likelihood and Gibbs sampling

Mixed model (co)variance component estimates by REML and Gibbs sampling for two traits were compared for base populations and control lines of Red Flour Beetle (Tribolium castaneum). Two base populations (1296 records in the first replication, 1292 in the second) were sampled from laboratory stock. Control lines were derived from corresponding base populations with random selection and mating for 16 generations. The REML estimate of each (co)variance component for both pupa weight and family size was compared with the mean and 95% central interval of the particular (co)variance estimated by Gibbs sampling with three different weights on the given priors: ‘flat’, smallest, and 3.7% degrees of belief. Results from Gibbs sampling showed that flat priors gave a wider and more skewed marginal posterior distribution than the other two weights on priors for all parameters. In contrast, the 3.7% degree of belief on priors provided reasonably narrow and symmetric marginal posterior distributions. Estimation by REML does not have the flexibility of changing the weight on prior information as does the Bayesian analysis implemented by Gibbs sampling. In general, the 95% central intervals from the three different weights on priors in the base populations were similar to those in control lines. Most REML estimates in base populations differed from REML estimates in control lines. Insufficient information from the data, and confounding of random effects contributed to the variability of REML estimates in base populations. Evidence is presented showing that some (co)variance components were estimated with less precision than others. Results also support the hypothesis that REML estimates were equivalent to the joint mode of posterior distribution obtained from a Bayesian analysis with flat priors, but only when there was sufficient information from data, and no confounding among random effects.

Comparison of (co)variance component estimates in control populations of red flour beetle (Tribolium castaneum) using restricted maximum likelihood and Gibbs sampling

Comparison of (co)variance component estimates in control populations of red flour beetle (Tribolium castaneum) using restricted maximum likelihood and Gibbs sampling

Evaluation of Diatomaceous Earth (Insecto) and Bacillus thuringiensis Formulations for Insect Control in Stored Peanuts2

Runner variety peanuts treated with four rates of diatomaceous earth (28.4, 56.8, 85.2, and 113.6 g per 12.7 kg peanuts) and Virginia variety peanuts treated with four Bacillus thuringiensis formulations (Dipel, Foil, M-Trak and Trident) were held for 8 months at ambient conditions in south Georgia and infested with stored-product insect pests. No red flour beetle, Tribolium castaneum (Herbst), adults were found in peanuts treated with diatomaceous earth until six months after treatment. After 8 months, red flour beetle populations in peanuts treated with diatomaceous earth ranged from 5.7 ± 1.9 to 32.8 ± 12.0 per kg, as compared to 221.2 red flour beetles per 12.7 kg peanuts in untreated controls. The effect of diatomaceous earth on red flour beetles was described by non-linear regression. Indianmeal moth, Plodia interpunctella (Hübner), and almond moth, Cadra cautella (Walker), populations were not abundant in untreated controls or the diatomaceous earth treatments. After 8 months, red flour beetle populations in peanuts treated with the four biological insecticides were not significantly different from the untreated controls. Low levels of Indianmeal moth and almond moth were present in all treatments.