Effects of rearing density, age, sex, and food deprivation on flight initiation of the red flour beetle (Coleoptera: Tenebrionidae)

Effects of rearing density, adult density and sex ratio in the flight chamber, adult age, sex, presence or absence of food, and duration of food deprivation on rate of and time to flight initiation of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), were studied in the laboratory. Rates of flight initiation were slightly lower at lower rearing densities, but they did not differ with age or sex of adults, presence or absence of food in the flight chamber, or duration of food deprivation. Focal adults were less likely to fly when individuals of the opposite sex were present in flight chambers. Presence of the same sex or mixed sexes and numbers of individuals in flight chambers did not affect tendency to fly of focal individuals. Mean time to flight of older beetles (7-20 d old) was less than that of younger beetles (1-4 d old). No young beetles flew during the first 24 h of flight tests. Mean time to flight did not differ with rearing density, sex, presence or absence of food, or duration of food deprivation. Our results indicate that this species is highly dispersive during the adult stage and that flight does not seem to be associated with just prereproductive or postreproductive dispersal phases, high rearing density, or short to medium periods of food deprivation. Therefore, T. castaneum level of flight activity does not seem to be associated with factors that have been shown in the literature to increase dispersal by walking for this species and to increase flight initiation in other stored-product species.     

Response of Tribolium castaneum and Rhyzopertha dominica to various resources,near and far from grain storage

Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.) are common cosmopolitan pests of stored grain and grain products. We evaluated the relative attraction of T. castaneum and R. dominica to wheat, sorghum and cotton seeds in the field, near grain storage facilities and well away from storages in southern and central Queensland using multiple trapping techniques. The results show that T. castaneum is more strongly attracted to linted cotton seed relative to wheat, whereas R. dominica did not respond to cotton seed at all and was attracted only to wheat. Significantly more adults of T. castaneum (10–15 times) were attracted to traps placed on the ground, near grain storage, than to equivalent traps that were suspended (1.5 m above the ground) nearby. These results suggest that Tribolium beetles detect and respond to resources towards the end of their dispersal flight, after which they localize resources while walking. By contrast R. dominica was captured only in suspended traps, which suggests they fly directly onto resources as they localize them. The ability of both species to colonize and reproduce in isolated resource patches within the relatively short time of 1 month is illustrated by the returns from the traps deployed in the field (at least 1 km from the nearest stored grain) even though they caught only a few beetles. The results presented here provide novel insights about the resource location behaviours of both T. castaneum and R. dominica. In particular, the relationship of T. castaneum with non‐cereal resources that are not conventionally associated with this species suggests an emphasis on these other resources in investigating the resource location behaviour of these beetles. This new perspective on the ecology of T. castaneum highlights the potential role of non‐cereal resources (such as the lint on cotton seed) in the spread of grain pest infestations.     

赤拟谷盗功能基因组学研究进展

赤拟谷盗Tribolium castaneum是一种重要的模式生物,在遗传、发育、生化与免疫等研究领域均取得了重要的研究进展。同时它也是一种危害极大的鞘翅目类储粮害虫,在世界各地都有分布,每年给储藏物造成了数十亿美元的经济损失。其全基因组测序的完成、遗传操作体系的构建及系统RNAi方法的应用都极大地促进了其功能基因组学的研究。本文综述了近年来赤拟谷盗基因组计划及功能基因组学的研究进展,拟为赤拟谷盗的生物学研究和防治奠定基础。     

Flight take-off performance of Colorado potato beetle in relation to potato phenology

The flight take-off frequency of adult Colorado potato beetles, Leptinotarsa decemlineata (Say), from potato plants, Solanum tuberosum L. 'Red Pontiac' at the bloom stage of development was 2.2-2.5-fold that of Colorado potato beetle from plants at the vegetative stage. Tests were conducted in a flight chamber over a period of 3 h. Prefeeding Colorado potato beetles for 48 h on potato plants at the bloom or at the vegetative stage before placing them into the flight chamber resulted in the same significantly higher flight take-off frequency from potato plants at the bloom stage than from plants at the vegetative stage. These results demonstrate that the factor in potato plants in bloom that stimulates the flight take-off of the Colorado potato beetle is independent of the feeding history of the beetles and begins acting only when the beetles are in the presence of the plant. According to these results, the dispersal of adult Colorado potato beetles from potato fields in bloom to younger potato fields with plants at the vegetative stage, previously reported in the literature, is at least partly explained by the effect of plant phenology on the frequency of flight take-off. Results confirm the value of planting potato fields of similar phenology over as wide an area as possible to reduce Colorado potato beetle dispersal between fields. Results also imply that staggering the planting dates of conventional potato refuge areas near Colorado potato beetle transgenic or conventionally resistant potato fields is a sound management practice, because it promotes the movement of wild beetles over to the adjacent younger resistant crops.     

The development of PCR-based markers for molecular sex identification in the model insect species Tribolium castaneum

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is a major pest of stored grain and cereal crops. It is also an important model species in genetic, ecological, and evolutionary research. The majority of its genome was recently sequenced and published. However, the genomic sequence of the small Y-chromosome is still undetermined, which hinders the development of molecular sex identification methods. Traditional methods for sexing adult forms of Tribolium beetles are troublesome. Therefore, a method for molecular sex identification in the red flour beetle was developed. One sex-linked randomly amplified polymorphic DNA marker was converted into a sequence-characterized amplified region (SCAR). The SCAR was aligned with the T. castaneum reference whole-genome sequence and fully matched a fragment of a single contig of unknown genomic location. The novelty of the method is that the fragment consists of shorter DNA fragments that are also present at other locations around the genome, but the particular order of these fragments within the sequenced region appeared to be Y-specific and this property was utilized for marker development. A set of three primers for multiplex PCR reaction was designed resulting in amplification of different length Y-specific and not-Y-specific (control) DNA fragments in a single PCR, which allows to distinguish males from females. The primers successfully sexed pre-sexed pupae and adult beetles from six laboratory strains, showing that the order of the repeated fragments is conserved in the species and is not strain-specific.     

Effect of Tribolium castaneum (Coleoptera: Tenebrionidae) nutritional environment, sex, and mating status on response to commercial pheromone traps

Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), the red flour beetle, is an important cosmopolitan pest of stored grains. Commercial traps baited with the synthetic aggregation pheromone 4,8-dimethyldecanal (DMD) are used to monitor T. castaneum population densities in storage facilities. However, trap catches may depend on several intrinsic and extrinsic factors. In this study, we explored the effects of beetle nutritional environment, sex, and mating status on the response of T. castaneum to commercial Storgard Dome traps. Beetles raised on a low-nutrition diet were 1.7 times more likely to enter DMD-baited traps compared with beetles that were raised on a high-nutrition diet. Although no sex difference in trap response was found, unmated beetles of both sexes were more responsive to DMD than were mated beetles, and this effect was especially pronounced for beetles reared on a low-nutrition diet. These results suggest that estimating T. castaneum population densities based on trap catches might be improved by incorporating information about the nutritional quality of infested stored products.     

Repellency and toxicity of oil from Artemisia annua to certain stored-product beetles

The essential oil of Artemisia annua L. was tested for its toxic repellent and development inhibitory activities against 2 economically important stored product insects: Tribolium castaneum (Herbst) and Callosobruchus maculatus (L.). Adult beetles of T. castaneum were repelled significantly by oil of A. annua at 1% concentration (vol:vol) and above in filter paper arena test. Dose-response relationship of A. annua oil revealed a significant negative correlation between larval survival; pupal survival and adult emergence of T. castaneum (i.e., increase in dose caused decrease in survival and adult emergence). Effective concentration (EC50) to reduce F1 progeny by 50% was calculated to be 2.6 and 4.1 microl/ml solvent against both the insect species, C. maculatus and T. castaneum, respectively. The relationship between bioactivity of oil from A. annua and responses of T. castaneum and C. maculatus is discussed. We found that oil from A. annua was largely responsible for both repellent (behavioral) and toxic (physiological) actions on 2 species of insect tested.     

Effect of d-limonene on three stored-product beetles

d-Limonene was investigated for contact and fumigant toxicity, ovicidal effects, oviposition-deterrent, development inhibition, and feeding-deterrent activities against three stored-product beetles (Coleoptera): lesser grain borer, Rhyzopertha dominica (F.); rice weevil, Sitophilus oryzae (L.); and red flour beetle, Tribolium castaneum (Herbst). Contact and fumigant toxicity decreased as larvae aged. Contact toxicity was similar for adults of the three species tested, but R. dominica was most susceptible to fumigant activity. T. castaneum oviposition decreased as concentration of d-limonene increased and d-limonene reduced oviposition up to 92.3% at the concentration of 2.14 mg/cm2. Hatching of d-limonene-treated eggs of T. castaneum was reduced by 94.5% with no subsequent larval and adult survival at 2.14 mg/cm2 concentration. A flour disc bioassay indicated 87.7 to 96.8% feeding-deterrency by d-limonene toward all three insect species tested at the highest concentration of 60.0 mg/g food. These results suggest that d-limonene can be effectively used to suppress populations of stored-product beetles.     

Chronological age-grading of three species of stored-product beetles by using near-infrared spectroscopy

The accuracy of near-infrared spectroscopy (NIRS) for predicting the chronological age of adults of the rice weevil, Sitophilus oryzae (L.); the lesser grain borer, Rhyzopertha dominica (F.); and the red flour beetle, Tribolium castaneum (Herbst), three pests of stored grain, was examined. NIRS-predicted age correlated well with actual age of these three species. Age predictions in S. oryzae by using the NIRS method are not dependent upon adult sex or temperatures to which adult weevils are exposed. Results indicated that water content decreased with increasing age in rice weevil adults, and excluding wavelengths at which water absorbs NIR radiation reduced the accuracy of correct classification. Additionally, removing cuticular lipids from insects resulted in a significant decrease in classification accuracy of weevils, indicating that these compounds may be partly responsible for the ability of NIRS to differentiate young from old beetles. NIRS is a nondestructive technique that can be used to age-grade large numbers of adult stored-product beetles, information that could help to increase the accuracy of population models for these pest species.     

Influence of age, mating status, sex, quantity of food, and long-term food deprivation on red flour beetle (Coleoptera: Tenebrionidae) flight initiation

Effects of age, sex, presence or absence of food, mating status, quantity of food, and food deprivation on rate of and time of flight initiation of the red flour beetle, Tribolium castaneum (Herbst), were determined. Flight initiation declined with increasing age in both presence and absence of food. However, flight initiation was lower when food was present in the flight chambers than in the absence of food. In the presence of food, both mated and virgin beetles were equally likely to disperse by flight. However, in the absence of food, mated beetles initiated flight more readily that virgin individuals. Flight initiation was greatest when little or no food was present. The presence of varying quantities of food inside the flight chambers impacted the number of progeny produced by females before flight, but not the timing of flight. Rate of flight initiation was higher for beetles deprived of food for short periods of time compared with flight initiation of beetles with food in the flight chamber. Flight initiation decreased with increasing time without food. There were no differences in flight tendencies between males and females in the experiments reported here. Our results suggest that T. castaneum uses flight as a mechanism to disperse to new environments during almost any part of their life span and that this type of dispersion does not fit with the model of the so-called true migratory species that involves an "oogenesis-flight syndrome.     

温度对赤拟谷盗爬行和起飞活动的影响

在不同温度下研究了赤拟谷盗Tribolium castaneum(Herbst)在固体物面、设定粮面、温度均匀的粮(小麦)柱和具有温度梯度粮柱内爬行扩散速度、起飞温度等.主要结果为:赤拟谷盗在17℃开始有爬行为,25℃开始有飞行行为,在15～25℃时水平爬行速度和15 ～ 20℃时竖直运动速度与温度呈显著正相关,在无障...     

Trends in the Evolution of Passively Dispersing Insects and the Feed-back Control in Phylogenesis

In each definite habitat the environmental conditions may change to a degree exceeding the degree of ecological plasticity of the given species; in such cases the population either must become extinct or its representatives must migrate to some new habitats. The lower its ecological plasticity, the greater is the significance of dispersal for the species. Dispersal may be active or passive. In active dispersal the possibility and probability for representatives of population to encounter suitable conditions depend on the perfection of their locomotory organs, organs of orientation in space and on capacity for energy production. Active dispersal requires high differentiation of organs and is consequently performed by the definitive stage of development. In passive dispersal (anemochory, phoresy etc.) the possibility to meet with favourable conditions is ruled out by the laws of random distribution. Therefore, for passively transported species, highest numbers of disseminating individuals and their smallest mass are advantageous. Consequently passive dispersal is performed, 1s a rule, by juvenile stages, whereas for the adults of the passively dispersing species, high sexual production is characteristic, connected with general degeneration of the organs of active life. For Insecta-Pterygota active dispersal by flight is typical. The appearance of adult Pterygota is that of the dispersing organism. The main functions of the adult stage in Pterygota are dispersal and reproduction, whereas those of the larva are feeding and growth. Only the function of active dispersal determines the progressive evolution of the imago in insects. Functions of dispersal and propagation approach each other in the time but the period of dispersal precedes that of reproduction. The wide separation of these functions in time leads to the regressive changes in adult females. Passing of the function of dispersal from the adult stage to passively disseminating larvae leads to regressive changes in the course of ontogenesis and to features of degeneration in adult females. In rather rare instances of passive dispersal of imagines additional means of propagation are developed (parthenogenesis, paedogenesis, polyembryony). Even in those groups of Pterygota where the females are highly degenerate the males do not exhibit any regression in locomotory and sense organs, still being able to fly. This is connected with the role of sexual reproduction for the persistence of characters, of genes. In the same manner as dispersal is a necessary condition for getting individuals of the species into appropriate environment, amphimixis is the premise for every gene, for each character, to meet with a favourable genetic environment. Sexual differences of adult insects reflect the phenotypic differences of gametes. Males ensure the encounter of sexes. Movements of pairing adults are of the same significance for the further persistence of genes, of characters, as the active dispersal flight of insect females is for the survival of individuals, for persistence of the species. Independent movements of spermatozoa in mating animals (especially in those with internal insemination) are of the same importance for genes dispersal as the crawling of first instar larvae (corrective movements) in actively (by flight) dispersing alate insects in the dispersal of a species.     

Flight directionality of Tribolium castaneum soon after take‐off under glasshouse and field conditions

Flight directionality of the rust‐red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), was investigated under glasshouse and field conditions using sticky traps placed around dense experimental infestations of T. castaneum derived from field‐collected samples. Although beetles of this species are known to fly quite readily, information on flight of beetles away from grain resources is limited. Under still glasshouse conditions, T. castaneum does not demonstrate strong horizontal or vertical trajectories in their initial flight behaviour. Flight was significantly directional in half of the replicates, but trapped beetles were only weakly concentrated around the mean direction of flight. In the field, by contrast, emigration of T. castaneum was strongly directional soon after flight initiation. The mean vector lengths were generally >0.5 which indicates that trapped beetles were strongly concentrated around the calculated mean flight direction. A circular‐circular regression of mean flight vs. mean downwind direction suggested that flight direction was generally correlated with downwind direction. The mean height at which T. castaneum individuals initially flew was 115.4 ± 7.0 cm, with 58.3% of beetles caught no more than 1 m above the ground. The height at which beetles were trapped did not correlate with wind speed at the time of sampling, but the data do indicate that wind speed significantly affected T. castaneum flight initiation, because no beetles (or very few; no more than three) were trapped in the field when the mean wind speed was above 3 m s^?1. This study thus demonstrates that wind speed and direction are both important aspects of flight behaviour of T. castaneum, and therefore of the spatio‐temporal dynamics of this species.     

七种糕点对赤拟谷盗(鞘翅目：拟步甲科)感染的抗性（英文）

Biscuits are flour-based products,which areconsumed by majority of people,both old and young,throughout the world and most especially by children,teenagers and mid-adults(Majumder,1970).It can beserved as a desert or snacks and as a breakfast foodwhentaken with beverages.Its ready-to-serve state andlong shelf life contribute to its acceptability by themasses.Wheat as humanfoodis used principallyintheformof flour for baked products such as bread,bis-cuits,pastries and crackers(Kent,1983).In th…     

Phosphine resistance in the rust red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae): inheritance, gene interactions and fitness costs

The recent emergence of heritable high level resistance to phosphine in stored grain pests is a serious concern among major grain growing countries around the world. Here we describe the genetics of phosphine resistance in the rust red flour beetle Tribolium castaneum (Herbst), a pest of stored grain as well as a genetic model organism. We investigated three field collected strains of T. castaneum viz., susceptible (QTC4), weakly resistant (QTC1012) and strongly resistant (QTC931) to phosphine. The dose-mortality responses of their test- and inter-cross progeny revealed that most resistance was conferred by a single major resistance gene in the weakly (3.2×) resistant strain. This gene was also found in the strongly resistant (431×) strain, together with a second major resistance gene and additional minor factors. The second major gene by itself confers only 12-20× resistance, suggesting that a strong synergistic epistatic interaction between the genes is responsible for the high level of resistance (431×) observed in the strongly resistant strain. Phosphine resistance is not sex linked and is inherited as an incompletely recessive, autosomal trait. The analysis of the phenotypic fitness response of a population derived from a single pair inter-strain cross between the susceptible and strongly resistant strains indicated the changes in the level of response in the strong resistance phenotype; however this effect was not consistent and apparently masked by the genetic background of the weakly resistant strain. The results from this work will inform phosphine resistance management strategies and provide a basis for the identification of the resistance genes.     

Wind as an abiotic factor of Colorado potato beetle (Coleoptera: Chrysomelidae) flight take-off activity under field conditions

The flight take-off activity of Colorado potato beetles, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), was significantly higher at a landscape-protected than at semiexposed and exposed sites in a 2-yr field study. In both years, mean daylight temperature, solar radiation, and relative humidity were generally similar at all sites, but wind speed was lower at the protected site than at the exposed sites. Results suggest that wind was the limiting abiotic factor for flight take-off at the exposed site. Caged beetles exposed to constant wind speeds of 3.4, 4.7, and 7.0 m/s showed a significant corresponding decrease in number of flight take-off. There was no cumulative effect of wind exposure on the readiness of the beetles to fly, suggesting that wind acts as a physical barrier to flight take-off. It should be possible to reduce Colorado potato beetle flight dispersal by selecting fields most exposed to wind over landscape-protected fields when rotating potato, Solanum tuberosum L., crops.     

Reproductive status and flight activity of the overwintered Colorado potato beetle

Mating behavior of post-diapause Colorado potato beetles, Leptinotarsa decemlineata (Say), was observed within an overwintering site, a rotated potato field, newly colonized potato plants, and under laboratory conditions. The influence of spring mating on beetle flight in the presence and in the absence of host plants was investigated using a computer-linked flight mill system. Diapause was terminated simultaneously in male and female beetles, and the first matings were observed as early as within the first 24 h after the beetles emerged from the soil (60–90 DD accumulated). The beetles mated within the overwintering site, the potato field, and the fields rotated out of potatoes. Mating status did not affect flight behavior of overwintered beetles; however, unfed beetles displayed higher flight activity than fed beetles. Most flight activity took place soon after flight muscle regeneration, and then declined sharply by the 5th day after flight initiation. Mating in or near overwintering sites soon after diapause termination might be an important factor in providing gene flow between insecticide-resistant and insecticide-susceptible Colorado potato beetle populations, and should be considered in designing resistance management plans.     

D.D.T. Impregnation of Sacks for the Protection of Stored Cereals Against Insect Infestation

Cotton flour sacks, jute flour sacks, jute bran sacks and jute grain sacks have been impregnated with 1 and 5 % by weight of D.D.T. Treated and untreated sacks, each containing 1 cwt. of a mixture of grain (5 parts) and weatings (1 part), were exposed to severe infestation by adults of Calandra granaria, Tribolium castaneum, Ptinus tectus, Oryzaephilus surina-mensis and Ephestia elutella . After storage for 15 weeks at a mean temperature of 21.3 C. and a mean relative humidity of 65 %, the numbers of adult insects in each sack were determined by sieving the contents.
The results with Ephestia elutella were inconclusive. The results with the four species of beetles showed that the eventual degree of infestation of the contents of the sacks was dependent upon the closeness of weave and the D.D.T. content of the sacking material. Impregnation of sacking with 1 % of D.D.T. should afford adequate protection against insect infestation to clean bagged goods stored in stowages which are not heavily infested. Impregnation with 5 % of D.D.T. should offer a very high degree of protection at all times and can almost entirely prevent infestation, if the treated material is of sufficiently close weave to afford some mechanical hindrance to penetration by insects.     

Energy use by the mountain pine beetle (Coleoptera: Curculionidae: Scolytinae) for dispersal by flight

The mountain pine beetle Dendroctonus ponderosae Hopkins is a major native pest of Pinus Linnaeus (Pinaceae) in western North America. Host colonization by the mountain pine beetle is associated with an obligatory dispersal phase, during which beetles fly in search of a suitable host. Mountain pine beetles use stored energy from feeding in the natal habitat to power flight before host colonization and brood production. Lipids fuel mountain pine beetle flight, although it is not known whether other energy sources are also used during flight. In the present study, we compare the level of energy substrates, proteins, carbohydrates and lipids of individual mountain pine beetles flown on flight mills with unflown control beetles. We use a colorimetric method to measure the entire metabolite content of each individual beetle. The present study reveals that mountain pine beetles are composed of more protein and lipid than carbohydrate. Both female and male mountain pine beetles use lipids and carbohydrates as energy sources during flight. There is variation between sexes, however, in the energy substrates used for flight. Male mountain pine beetles use protein, in addition to lipids and carbohydrates, to fuel flight, whereas protein content is not different between flown and control females.     

Dispersal capacity in the Mediterranean corn borer, Sesamia nonagrioides

Corn (Zea mays L.) borers are the primary target of Bacillus thuringiensis Berliner (Bt) transgenic maize. Management of corn borer resistance to Bt requires information on larval and adult dispersal capacities, a feature that is particularly unknown in Sesamia nonagrioides Lefèbvre (Lepidoptera: Noctuidae), the most damaging corn borer in Spain. Larval dispersal was studied over a 3 year period by infesting plants with egg masses and dissecting the neighbouring plants 7, 14, and 32 days later to measure larval dispersal at several ages. The number and age of larvae were recorded in the dissected plants. Only mature larvae dispersed in significant numbers; they moved at least to rows adjacent to those containing the infested plant, and down the row five plants. The percentage of larvae that dispersed from the infested plant was density‐dependent. Adult dispersal was studied with directional light and pheromone uni‐traps over 5 and 3 year periods, respectively. Directional light traps were placed in the margins between Bt and non‐Bt maize fields, half oriented towards each of the two kinds of maize field. Pheromone traps were placed in the Bt and non‐Bt fields at increasing distances (0–100 m) from the border. The numbers of males and females caught in directional light traps were not different in traps oriented towards Bt or non‐Bt fields, but the number of males caught in the third flight in Bt fields was lower than in non‐Bt fields. These results suggest that males from adjacent Bt and non‐Bt fields mate indiscriminately with females emerging in any of the two kinds of maize fields. However, male movement in the third flight may not be sufficient to randomly distribute males between the two fields.