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The survey was conducted to assess the diversity, abundance and infestation level of bruchids in pulse storages across 13 locations in Karnataka. A total of 23 stored grain samples representing eight pulses were collected from small and large scale stored conditions. The samples were observed for grain moisture content and infestation parameters. The grain moisture content was found within the recommended range for safe grain storage (< 12 %). The associated bruchids were identified and species diversity, abundance and dominance was computed. The bruchids were belonged to five species of genus, Callosobruchus (Callosobruchus chinensis L., C. maculatus F., C. analis F., and two were unidentified Callosobruchus spp.) which were found infesting different pulses. Species diversity was found higher in small scale storage conditions (H=0.56) than large scale storages (H=0.39). Among the bruchid species, C. chinensis (~65 %) was found to be most abundant species at maximum locations and crops followed by C. maculatus (~53 %), however, under large scale storage conditions, C. analis (54 %) was abundant. The most dominant species under large scale storages was C. analis (d=0.54), whereas, C. maculatus (d=0.45) was found to be most dominant under small scale storages. The seed weight loss was influenced by egg and adult density rather than per cent infestation and damage. Interestingly, higher grain moisture and prolonged storage duration were found influencing infestation and grain damage significantly. This study opens further window to understand the bruchid species infesting stored pulses during different times of the year, present effective management options including natural enemies and the present level of susceptibility of bruchids to the monopoly chemical option Aluminium phosphide. [ABSTRACT FROM AUTHOR]

In order to develop a strategy for the safe management of insect pests in stored agricultural commodities, Anserine (Chenopodium ambrosioïdes (L.)) essential oil was tested against Cowpea weevil (Callosobruchus maculatus) raised on seeds of Chickpea (Cicer arietinum) at 20–30°C and 65 ± 5% relative humidity in storage conditions. The essential oil extracted from Chenopodium ambrosioïdes (L.) was analysed by gas chromatography coupled with mass spectrometry (GC/MS). The chromatogram of the essential oil of Chenopodium ambrosioïdes (L.) contains 13 compounds of which α-Terpinene is the majority constituent with a percentage of 61.04%. The results obtained have shown that the essential oil of Chenopodium ambrosioïdes (L.) has repellent and toxic effects on Callosobruchus maculatus. It causes a high mortality rate in adults and affects its fecundity, fertility and success rate in a very significant way compared to controls. [ABSTRACT FROM AUTHOR]

Laboratory experiment was carried out in Marshes Researches Center lab in University of Thi-Qar in Iraq during May 2019, to evaluate for three botanical powder effects, Cinnamon (Cinnamomum Cassia), Cubeb (Piper Cubeba) and Mint (Mentha spp.) against southern cowpea beetle Callosobruchus maculates on Mung bean stored seeds. The experiment carried out according to factorial precision in complete randomized design (CRD) to estimating the Mortality ratio and the complete randomized design (CRD) to estimating seed weight losses ratio and seed germination ratio. The results showed that there was significant effect for all treatment powders of Callosobruchus maculatus mortality ratio on the Mung Bean seeds except the mass fractions of Mint powders was not significant, the results showed that the highest average mortality ratios of insect was 52.58 and 62.47% to the mass fraction (4g powder) for Cinnamon and Cubeb powder respectively, For the exposure periods, the results showed that the highest mortality ratio of the insect was 100% for the periods 9-12, 8-12 and 10-12 days for Cinnamon, Cubeb and Mint powders respectively. The overlapping effect of exposure durations and mass fractions, the highest ratio reached 100% for all the mass fractions for the periods 9-12 days of Cinnamon powder and it reached 100% for mass fraction of 4grm powder for the periods 7-12 days and mass fractions 0.5, 1and 2g powder for the periods 8-12 days for Cubeb powder and it reached 100% for mass fractions 0.5, 1and 2g for the periods 9-12days and mass fraction of 4g for the periods 10-12 days. The effect of infestation with insect of Seed weight loss was significantly, the highest average of percentage loss in the weight of seeds and reached 5.62% after a period 35 of days of storage. The results showed that there were no significant effects in averages of germination ratio of Mung Bean seeds treated with vegetable powders under consideration. [ABSTRACT FROM AUTHOR]

Rhynchosia beddomei is a deciduous endemic shrub. The present study on the pollination ecology of this shrub provided information to understand its endemic status. The study showed that the flowers are hermaphroditic with explosive pollination mechanism, self-compatible, facultatively xenogamous and melittophilous. The flowers not visited by bees fall off while those visited and pollinated by them set fruit. The beetle, Callosobruchus maculatus causes pod infestation. Pods dehisce explosively to disperse seeds, which germinate during rainy season. But their growth is suppressed due to soil moisture deficiency amplified by nutrient deficient rocky terrain. Therefore, this shrub is unable to populate effectively. Leaf cut during leaf flushing time by locals for medicinal purposes is an additional factor affecting the vegetative growth, flowering and fruiting rate of this shrub. Its use for traditional medicine needs to be regulated in order to conserve and manage the existing population. [ABSTRACT FROM AUTHOR]

Nearly all mungbean cultivars are completely susceptible to seed bruchids (Callosobruchus chinensis and Callosobruchus maculatus). Breeding bruchid- resistant mungbean is a major goal in mungbean breeding programs. Recently, we demonstrated in mungbean (Vigna radiata) accession V2802 that VrPGIP2, which encodes a polygalacturonase inhibiting protein (PGIP), is the Br locus responsible for resistance to C. chinensis and C. maculatus. In this study, mapping in mungbean accession V2709 using a BC11F2 population of 355 individuals revealed that a single major quantitative trait locus, which controlled resistance to both C. chinensis and C. maculatus, was located in a 237.35 Kb region of mungbean chromosome 5 that contained eight annotated genes, including VrPGIP1 (LOC106760236) and VrPGIP2 (LOC106760237). VrPGIP1 and VrPGIP2 are located next to each other and are only 27.56 Kb apart. Sequencing VrPGIP1 and VrPGIP2 in "V2709" revealed new alleles for both VrPGIP1 and VrPGIP2, named VrPGIP1-1 and VrPGIP2-2, respectively. VrPGIP2-2 has one single nucleotide polymorphism (SNP) at position 554 of wild type VrPGIP2. This SNP is a guanine to cystine substitution and causes a proline to arginine change at residue 185 in the VrPGIP2 of "V2709". VrPGIP1-1 has 43 SNPs compared with wild type and "V2802", and 20 cause amino acid changes in VrPGIP1. One change is threonine to proline at residue 185 in VrPGIP1, which is the same as in VrPGIP2. Sequence alignments of VrPGIP2 and VrPGIP1 from "V2709" with common bean (Phaseolus vulgaris) PGIP2 revealed that residue 185 in VrPGIP2 and VrPGIP1 contributes to the secondary structures of proteins that affect interactions between PGIP and polygalacturonase, and that some amino acid changes in VrPGIP1 also affect interactions between PGIP and polygalacturonase. Thus, tightly linked VrPGIP1 and VrPGIP2 are the likely genes at the Br locus that confer bruchid resistance in mungbean "V2709". [ABSTRACT FROM AUTHOR]

Essential oils (EO) obtained from Xylopia parviflora root bark and Hoslundia opposita leaf via hydro distillation were analysed by GC-MS and evaluated for their insectifugal (repellent) and insecticidal activities against cowpea seed bruchid ( Callosbruchus maculatus Fabricius), a cosmopolitan pest of cowpea seeds. X. parviflora was predominated by sesquiterpenes (59.57%), with the main compounds being β-himachalene (22.68%), 1,7,7,Trimethylbicyclo[2.2.1]hept-5-en-2-ol (19.68%), β-elemene (14.41%), 5(1H)-Azulenone, 2,4,6,7,8,8a-hexahydro-3,8-dimethyl-4-(1-methylethylidene)-(85-cis)- (12.38%) and (−)-α-parasinsen (8.34%). The predominant compounds in H. opposita EO were 1,8-cineole (61.15%), followed by α-terpineol (16.81%) and β-phellandrene (13.25%). Percentage repellence at application rates of 0.66-1.32 μl/cm (46.93-73.07%) was significantly ( p < 0.05) higher than that of control (17.73%). RD (repellence dose for 50% of treated adults) for H. opposita (0.43 μl/cm) was not significantly different from the value for X. parviflora (0.60 μl/cm). Although higher percentage of male mortality than female mortality was observed due to topical application of the EOs, the disparity was not significant. The results of correlation of the chemical groups of the EOs with the insectifugal activity indicate that the observed bioactivity was due to the synergistic effects of the chemical groups. The two EOs are therefore recommended for incorporation into bruchid protection schemes in the tropics. [ABSTRACT FROM AUTHOR]

A fumigant toxicity tests were performed by using airtight plastic jars, in which five small glass tubes with perforated lids containing 20 cowpea seeds and four newly emerged Callosobruchus maculatus were placed. Filter paper impregnated with an appropriate volume (5, 10, 20, 40 µl/ml) of the oils were attached to the lower surface of the jar lid. Mortality counts were made at 6, 12, 24 and 48 h after treatment. For ovicidal activity, seeds having 20 eggs altogether were put in a glass vial and the treatments were followed as mentioned earlier. After 48 h of exposure the seeds with eggs were transferred and ovicidal activity was calculated based on the adult emergence. Among the essential oils tested, five oils, viz. camphor, eucalyptus, nutmeg and rosemary showed 100 % mortality even at lower dosages (5 µl) when adults were exposed for 48 h.Onthe other hand, seven oils showed 100% mortality at higher concentration (40 µl). Ovicidal activity revealed that 9 oils showed good activity against C. maculatus at higher concentrations. Among them four oils, viz. camphor, eucalyptus, rosemary and wintergreen showed 100 % egg mortality. In this work, it can be concluded that camphor, eucalyptus, nutmeg, rosemary, wintergreen oils showed very good fumigant and ovicidal activity. However, the possibility of utilising these plant oils to control C. maculatus in storage conditions may warrant further investigation. [ABSTRACT FROM AUTHOR]

The susceptibility of six green gram (Vigna radiata W.) varieties and quantitative losses due to pulse beetle, Callosobruchus chinensis L., were studied under laboratory conditions. No green gram varieties were found immune. They showed different magnitude of weight loss. The lowest weight loss was observed in variety HUM-12, HUM-1 with 30.20, 31.83, respectively and lowest percent germination loss was observed in variety HUM-2, HUM-16 with 2.50, 2.70, respectively. The mean seed damage and weight loss was 8.98 and 8.26 per cent, respectively after 30 days. This was increased with the storage duration resulting in 99.99 and 48.62 per cent, respectively after 120 days of storage. The population of pulse beetle and Percent germination losses was increases with increasing storage duration. [ABSTRACT FROM AUTHOR]

As part of our ongoing search for natural fumigants from Senegalese plants, we have investigated Securicicidaca longepedunculata root barks and demonstrated that 2-hydroxy-benzoic acid methyl ester (methyl salicylate, I) is responsible of their biocide effect against stored grain insects. A second unknown apparented product, II has been systematically observed in all analyzed samples. The present paper describes the identification of this molecule. The analytical investigations including GCMS, GLC and 1H-NMR. spectrometry led to the conclusion that II corresponds to the 2-hydroxy-6-methoxybenzoic acid methyl ester.

In this study, the insecticidal effect of Poppy (Papaver somniferum) seed oil was investigated againstCallosobruchus maculatus(Bruchidae) in cowpea, at different concentrations and exposure time. The Poppy seed oil at 2, 4, 6, 8 and 10 ml/kg was tested against adults ofC. maculatus, and the mortality was counted after 24, 48 and 72 h of exposure. All tests were conducted at 27–30 °C and 65 ± 5% r.h. The experiments were carried out based on the factorial experiment by randomized complete design with four replications. Twenty-five insects with 0–24 h old were used for each replication. The effect of Poppy seed oil on the reduction of emergence of insects in next generation (F1) was also assayed. The results of experiments indicate the significant differences between concentrations and exposure time (p < 0.0001), and the increase of concentrations and exposure time increased mortality. The amount of mortality at high concentrations was remarkable, and highest mortality rate (96.91%) was recorded at 10 ml/kg, after 72 h of exposure. The application of oil significantly reduced F1progeny production and even at lowest concentration (2 ml/kg), the amount of F1production was reduced more than 70%, compared with control treatment. Complete (100%) reduction in progeny production was recorded at the rates of 8 and 10 ml/kg. The results of seed germination assay showed no significant differences between control and treated seed, and no harmful effect was observed on the seed germination. These results proved that Poppy seed oil can be used as a controlling agent of storage pests, especiallyC. maculatus, although more detailed studies are necessary. [ABSTRACT FROM PUBLISHER]

Geographic populations of a widespread species can differ in their ability to adapt to a novel environment because they possess different amounts of the requisite genetic variation. We compared responses to the same novel host in ecologically and genetically divergent populations of the seed beetle Callosobruchus maculatus (F.). Populations from Africa and Asia had been derived from and maintained on different legume hosts. In preselection assays, both populations exhibited lower survival, slower development, and smaller size on a third host (adzuki bean), and the difference in performance between the ancestral and novel hosts was especially high for the African population. Replicate lines of each population were switched to adzuki bean or maintained on the ancestral host, and beetle performance was measured on both hosts after 12 generations. Survival on adzuki bean increased substantially in the adzuki-bean lines of the African population, but improved only slightly in the Asian lines. Similarly, only the African adzuki-bean lines exhibited significantly faster development on adzuki bean. Improved performance on adzuki bean did not simultaneously reduce performance on the ancestral host. Together with previous studies, these results confirm that populations of C. maculatus often possess sufficient standing genetic variation for rapid adaptation to a novel host, but the magnitude of the response may depend on the source population. Although international trade in grain legumes can expand beetle host ranges and produce unusual biotypes, the consistent absence of strong genetic trade-offs in larval performance or adult oviposition across hosts makes it unlikely that this insect would form distinct host races. [ABSTRACT FROM AUTHOR]

Pulse beetles Callosobruchus chinensis and Callosobruchus maculatus are the most serious pests in stored legumes in majority of tropical countries. Attention has been given to the possible use of plant products or plant derived compounds as promising alternatives to synthetic insecticides in controlling insect pests of stored products. Various indigenous plant species in different forms such as crude ethanol (CE) extracts, vegetable oils, dry powders and combinations of plant materials with insecticides and effect of their concentration were tested against Callosobruchus spp. in laboratory conditions. The highest bioactivity (90 - 100% mortality) was manifested by the crude ethanol extracts of Azadirachta indica (Neem), Anona reticulata (Anona) and Ocimum sanctum (Maduruthala/sacred bail) among the crude ethanol extracts tested. Oils of O.sanctum at 1.5 μL and A.reticulata at 3.0 μL completely inhibited oviposition and adult emergence. Clove powder was the most effective among the four powders tested for adult mortality followed by root dust of papaya. Among the plant powders tested, Maduruthala (O. sanctum) was the most effective for suppressing oviposition significantly followed by Getathumba (Leucas zeylanica). Our experiments also revealed enhanced toxicity and persistence of the insecticide in causing significant mortality to Callosobruchus spp. when combined with vegetable oils. Further, these results revealed that the potential applicability of some indigenous plant materials as stored grain protectants. The modes of action of these substances are not yet known and further studies must be carried out especially to clarify how it is involved in the physiology of reproduction. [ABSTRACT FROM AUTHOR]

Adult longevity for mated and unmated individuals of Callosobruchus chinensis L. (both male and female) was studied separately with adults emerging from nine different pulses at both controlled temperature (28 ±2°C) and room temperature (23.8-31.5°C) in the laboratory. Further, the longevity for mated females was also studied separately providing food for oviposition and without providing food for oviposition. At both controlled and room temperature, the males developing in green gram and chickpea (deshi) had the longest average longevity (11.83 and 11.33 days, respectively), while the males developing in soybean had the shortest average longevity (7.50 and 7.00 days, respectively). Similarly, at both controlled and room temperature, the females developing in green gram and chickpea ( deshi) had the longest average longevity (10.00 and 9.56 days, respectively), while the females developing in soybean had the shortest average longevity (6.56 and 6.11 days, respectively). The unmated males lived longer (avg. 11.24 days) than mated ones (avg. 8.79 days). The longevity for mated female increased when they were provided food for oviposition as compared to those without providing food for oviposition. The unmated females lived longer (avg. 9.83 days) than mated females with food and without food (avg. 8.04 and 7.69 days, respectively). [ABSTRACT FROM AUTHOR]

The development of Callosobruchus maculatus on five different varieties of pulses were studied. The cowpea variety CoCp-7 recorded significantly highest number of eggs oviposited and percentage adult emergence, the shortest developmental period, highest susceptibility indices and the highest weight loss. Dobie's susceptibility index showed that the cowpea variety CoCp-7 and Co-6 were found to be highly susceptible to C.maculatus, whereas greengram varieties Km-2 and VBN2 were found to be moderately resistant to C.maculatus. The blackgram varieties VBN3 and VBN4 were resistant and regarded as non-suitable hosts for the development of C.maculatus. [ABSTRACT FROM AUTHOR]

Africa produces more cowpea (Vigna unguiculata) than any other continent but utilization in many countries is reduced due to seed destruction by the larvae of bruchids. The dried edible seeds of legumes are frequently attacked by beetles of the family Bruchidae. There are several genera of stored-product bruchids associated with a range of host plants. Callosobruchus species are the major bruchid pests of cowpea in Africa. Callosobruchus maculatus is the major pest of stored cowpea in Africa. Damage to cowpea seeds by C. maculatus during storage is widespread in Africa and constitutes a major constraint to food availability. Cowpeas damaged by C. maculatus have reduced weight, poor germinating ability and are unfit for human consumption, due to loss of vital nutrients such as vitamins and thiamine. It is during storage that cowpeas suffer heavy quantitative and qualitative losses from the attack by C. maculatus. Even though there are various methods of control of C. maculatus, some of the effective methods such as chemical insecticides pose environmental, social, financial and safety considerations in the tropics. There is need for alternative and less hazardous methods of control. Solar heating of cowpeas to control C. maculatus is one of the safe methods. However, steaming is thought to cause some physical modifications such as starch gelatinization and protein denaturation leading to a case hardening "effect" on the surface cell layers of the cotyledons and could therefore be used as alternative method of control. In the present study, the effects of steam treated, solar heat treated and untreated cowpea seeds on the development and control of C. maculatus were studied under ambient laboratory conditions (temperature range 28.0 - 30°C and 62 - 74% RH). There was no significant difference (P> 0.05) in the number of eggs laid by C. maculatus under conditions 1 male: 1 female, 5 males: 5 females,12 males: 12 females on treated and untreated cowpea seeds. C. maculatus developed successfully in untreated and solar heat treated cowpea seeds, but could not develop in steam treated cowpea seeds. Thus, the novel method of steam treatment of cowpea seeds is a useful pest management strategy that can be used to prevent C. maculatus infestation of cowpea seeds meant for long-term storage and consumption since the cooking properties and processing qualities of the cowpea were not affected. [ABSTRACT FROM AUTHOR]

The pulse beetle Callosobruchus chinensis Linn. (Coleoptera:Bruchidae) is one of the major pests of pulses in storage. During the present study an attempt was made to screen and compare the efficacy of Ocimum sanctum and Ocimum basilicum (Lamiaceae) on egg-laying performance of the bruchid on grains of Vigna radiata (mung). The leaves of the select two plants were employed in the form of crude extract, powder suspension, aqueous extract, ethanol extract and diethyl ether extract at dose concentrations of 10, 25 and 50%. Significant reduction (P< 0.05) in oviposition was documented in sets treated with the formulations of both the plants as compared to control and normal. The formulations of O. basilicum were observed to be superior to O. sanctum in reducing egg-laying. Moreover, ethanol extract, crude extract and powder suspension were also noted to significantly bring down the number of eggs laid by the pulse beetle. Dose concentration was found to be inversely proportional to the number of eggs laid by the bruchid and formulations of 50% concentration resulted in minimum oviposition. The results suggest that formulations of both the species of Ocimum have a potential to act as ovipositional deterrent and can be employed against C.chinensis for its control. [ABSTRACT FROM AUTHOR]

1. Transgenerational effects, genetic or non-genetic, affect population dynamics and the evolution of life-history traits. Besides genetic components, the size of gametes (eggs and seeds), simultaneously a parental and progeny character, can mediate environmental condition experienced by a parent. In both animals and arthropods, mothers are known to reduce their egg mass depending on their malcondition. 2. Progeny may also modify their life history traits to increase their own fitness when constrained by maternal investment, which may eventually nullify transgenerational effects on population dynamics and evolution. Such fitness modification by the progeny under new environmental conditions requires phenotypic plasticity interacting with egg mass. We hypothesize that different selective environments should produce inter-population genetic diversification of the response to maternal investment on each egg, which would be detected as a paternal genotype × environment × previous (i.e. maternal) environment (G × E × preE) interaction in progeny fitness. 3. To evaluate the contribution of maternal non-genetic resource and the genetic component separately, we used an inbred-isofemale-line approach to eliminate the influence of the genetic correlation between egg mass and other life history traits, in the adzuki bean beetle, Callosobruchus chinensis. The females were reared at either high or low densities to generate variability in egg resources. To test the additive or interactive effect of genotype, non-genetic egg resources, and maternal environment on the life history traits of the progeny, they were crossed with males from laboratory and wild strains that had been subjected to different levels of population density . 4. The G × E × preE interaction effect was detected on the correlation structure between egg mass and development time: In the offspring of mothers reared at low density, the negative correlation between egg mass and development time was higher with lab strain fathers, whereas in the offspring of mothers reared at high density, the negative correlation was higher with the wild strain fathers. 5. Our results indicate a genetic difference in the response of development time but not of adult mass to environmental variation in egg mass. Such density-dependent enhancement of maternal effects may destabilize population dynamics and accelerate evolution. [ABSTRACT FROM AUTHOR]

A water balance study was conducted on newly-emerged adults of seed beetle, Callosobruchus maculatus, to explore how South India strain survives longer than Brazil strain in laboratory cultures. No difference between strains was noted with regard to dehydration tolerance, and water conservation features confirm classification of this species as xerophilic. There was no evidence for critical transition temperature (CTT), thereby safeguarding against excessive water loss as the temperature rises, or for critical equilibrium humidity (CEH), indicating that water is imbibed as a liquid. In contrast to the Brazil strain, adults of the South India strain were distinguished by a larger body size, resulting in a lower net transpiration rate with suppressed activation energy (Ea, permeability constant) for water loss, and a lower percentage body water content due to a higher dry mass (fat). These modifications for water balance of the South India strain link enhancing time for reproduction and distribution spread in the adult with the higher seed consumption/respiratory rate trait that has been previously reported for larvae of this strain. [ABSTRACT FROM AUTHOR]

Callosobruchus chinensis is a major stored pest of pulses in India. Biology of pulse beetle was studied during 2005-2006 in the laboratory. The average incubation period, larval + pupal period, and adult longevity of male and female were 4.0, 16.4, 11.0 and 9.6 days respectively. The average of total developmental period (egg to adult) was 25.2 days, and pre-oviposition, oviposition and post-oviposition period were 0.4, 8.0 and 2.2 days, respectively. The average fecundity of the females was 85.6 eggs and its viability 94% during its life time. The effect of seven botanicals at 4.0 and 8.0 % w/w/100 grams of mungbean on mortality of Callosobruchus chinensis Linn. were also studied. Observations were taken on 2, 4 and 6 days after treatment. The seven plant materials, viz. neem leaf, chilli, NSK, tulsi leaf, nerium leaf, lantana leaf, Tobacco leaf including control were evaluated for their effects against pulse beetle. Among all these plant products, neem leaf (8 gm) was found more effective with 38.33 % mortality whereas nerium leaf (4 gm) was found least effective with 5.70 % mortality. [ABSTRACT FROM AUTHOR]

In species where males provide nuptial gifts, females can improve their nutritional status and thus increase their fecundity by mating when in need of resources. However, mating can be costly, so females should only mate to acquire resources when the need for resources is large, such as when females are nutritionally-deprived. Two populations of the seed-feeding beetle Callosobruchus maculatus, a species that produces relatively large nuptial gifts, are used to test whether female nutritional status affects mating behaviour. Female access to water, sugar and yeast are manipulated and the fitness consequences of these manipulations are examined together with the effects of diet on the propensity of nonvirgin females to mate. Access to water has a small but significant effect on mass loss over time, lifespan and fecundity of females, relative to unfed controls. Access to sugar (dissolved in water) improves female fecundity and lifespan above that of hydrated females but access to yeast has no positive effects on female survival or reproduction. Diet has a large effect on both receptivity of nonvirgin females to a male and how quickly they accept that male. Unfed females are both more likely to mate, and accept a mate more quickly, than females provided access to water, which are more likely to mate and accept a mate more quickly than females provided with sugar. This rank order of behaviours matches the order predicted if females increase their mating rate when nutritionally deprived (i.e. it matches the effect of diet on female fitness). The results obtained also suggest that mate choice may be condition-dependent: females from one population (Burkina Faso) show a preference for large males when well-fed but not when unfed, although this result is not found in a second population (South India). It is concluded that nutritionally-deprived females are more receptive to mates than are well-fed females, consistent with the hypothesis that females ‘forage’ for nuptial gifts, or at least more willingly accept sperm in exchange for nuptial gifts, when they are nutritionally deprived. [ABSTRACT FROM AUTHOR]

Reproduction can be costly and is predicted to trade-off against other characters. However, while these trade-offs are well documented for females, there has been less focus on aspects of male reproduction. Furthermore, those studies that have looked at males typically only investigate phenotypic associations, with the underlying genetics often ignored. Here, we report on phenotypic and genetic trade-offs in male reproductive effort in the seed beetle, Callosobruchus maculatus. We find that the duration of a male's first copulation is negatively associated with subsequent male survival, phenotypically and genetically. Our results are consistent with life-history theory and suggest that like females, males trade-off reproductive effort against longevity. [ABSTRACT FROM AUTHOR]

1. Reproductive interference is a negative interspecific sexual interaction that adversely affects the fitness of males and females during reproductive process. Theoretical studies suggest that because reproductive interference is characterized by positive frequency dependence it is far more likely to cause species exclusion than the density dependence of resource competition. However, the respective contributions of resource competition and reproductive interference to species exclusion, which have been frequently observed in many competition studies, remain unclear. 2. We show that reproductive interference is a far more critical cause of species exclusion than resource competition in the competition between Callosobruchus bean weevil species. In competition experiments over several generations, we manipulated the initial relative abundance of the adzuki bean beetle, Callosobruchus chinensis, and the southern cowpea beetle, Callosobruchus maculatus. When the initial adult ratio of C. chinensis : C. maculatus were 6 : 2 and 4 : 4, C. chinensis excluded C. maculatus. However, when C. maculatus was four times more abundant than C. chinensis at the start, we observed the opposite outcome. 3. A behavioural experiment using adults of the two species revealed asymmetric reproductive interference. The fecundity and longevity of C. maculatus females, but not those of C. chinensis females, decreased when the females were kept with heterospecific males. Fecundities of females of both species decreased as the number of heterospecific males increased. In contrast, resource competition at the larval stage resulted in higher survival of C. maculatus than of C. chinensis. 4. These results suggest that the positive frequency-dependent effect of reproductive interference resulted in species exclusion, depending on the initial population ratio of the two species, and the asymmetry of the interference resulted in C. chinensis being dominant in this study, as in previous studies. Classical competition studies should be reviewed in light of this evidence for reproductive interference. [ABSTRACT FROM AUTHOR]

Bruchids (Coleoptera: Bruchidae) can cause serious damage to mungbean and several other leguminous crops and there is a strong association between small seed size and bruchid resistance. In investigating the feasibility of breeding large-seeded cultivars with high levels of bruchid resistance, we studied the relationship between these two traits by QTL analysis. A major locus conferring resistance to Callosobruchus chinensis was identified from a wild mungbean genotype, ‘ACC41’ (belonging to Vigna radiata var. sublobata), collected in Australia. The proportion of the C. chinensis resistance response that could be attributed to this single QTL varied among four different resistance assays. The highest value reached was 98.5%, suggesting that bruchid resistance in this genotype is likely conditioned by this single locus. The QTL was robust and its detection was not affected by the use of different sources of the insect, different lengths and conditions of seed storage, or different bruchid resistance assay methods. This bruchid resistance QTL was coincident with one of the loci conferring seed mass detected from the three seed sources produced in Australia. However, such a co-location was not detected for the seed source produced in China. Covariance analysis revealed a complex relationship between seed mass and bruchid resistance. Nevertheless, the effect of the bruchid resistance QTL remained highly significant for all four assays after the effect of seed mass was accounted for. These results, together with the relationship between the bruchid resistance QTL identified in this study and a second one detected previously in a wild mungbean genotype from Madagascar, are discussed. [ABSTRACT FROM AUTHOR]

Abstract: The bruchid beetle, Callosobruchus chinensis (L.) and C. maculatus (F.) (Coleoptera: Bruchidae), are important stored-product insects of stored legume seeds. In this study, the external morphologies of the antennal sensilla on the antennae of both female and male adults of these two species were described using scanning electron microscopy. Antennae of both species are made up of the scape, pedicel, and nine segments of flagellomeres. Antennae of female and male C. maculatus and female of C. chinensis are serrate in shape, while those of male C. chinensis are pectinate. Eight morphological sensilla types were recorded in both sexes, including Böhm bristles (BB), two types of sensilla trichoid (ST1, ST2), sensilla chaetica (SC), two types of sensilla basiconic (SB1, SB2), grooved pegs (GP), and sensilla cavity (SCa). The number of ST1 and SB1 of the male were significantly greater than those of the female of C. chinensis, and the number of ST2 and SB1 of the male were significantly more abundant than those of the female of C. maculatus. The possible functions of the above sensilla types are discussed in light of previously published literature. [Copyright &y& Elsevier]

Female seed beetles, Callosobruchus maculatus, mate multiply even though association with males and copulations carry costs, such as injury to the genital tract. Multiple mating (polyandry) may, however, offset these costs through the acquisition of food and water, two material benefits hypothesized to be obtained from the large ejaculates produced by males. The material benefits hypothesis can be tested by increasing female access to nutrients and water, with the prediction that female mating frequency will decrease as copulation is no longer required to derive these materials. Females were given water, 5% sugar–water or baker’s yeast, and were compared with females deprived of these. We presented females with virgin males daily for 8 days and recorded female mating frequency, survivorship, and fecundity. Females provided with water and sugar–water decreased mating frequency. Thus, water, rather than nutrients in the ejaculate, appears to be important to females of this species. In addition, both life span and fecundity were extended for females in the sugar–water and water treatments. Since water is scarce in the arid environment in which this species is found, we conclude that polyandry provides material benefits to females that may offset some of the costs of associating with males. [ABSTRACT FROM AUTHOR]

1. To quantify the interactions between density-dependent, population regulation and density-independent limitation, we studied the time-series dynamics of an experimental laboratory insect microcosm system in which both environmental noise and resource limitation were manipulated. 2. A hierarchical Bayesian state-space approach is presented through which it is feasible to capture all sources of uncertainty, including observation error to accurately quantify the density dependence operating on the dynamics. 3. The regulatory processes underpinning the dynamics of two different bruchid beetles ( Callosobruchus maculatus and Callosobruchus chinensis) are principally determined by environmental conditions, with fluctuations in abundance explained in terms of changes in overcompensatory dynamics and stochastic processes. 4. A general, stochastic population model is developed to explore the link between abundance fluctuations and the interaction between density dependence and noise. Taking account of time-lags in population regulation can substantially increase predicted population fluctuations resulting from underlying noise processes. [ABSTRACT FROM AUTHOR]

1. Despite the obvious importance of spermatozoa to individual reproductive success a general explanation of variation in spermatozoan form and function is still lacking. In species with internal fertilization, sperm not only have to interact with the physical and biochemical environment of the female reproductive tract, but frequently face competition from the sperm of rival males. Both sperm competition theory and adaptation to the selective environment of the female reproductive tract have been implicated in the evolution of spermatozoan morphological diversity. 2. Using the comparative method, we examine variation in sperm length in relation to (i) sperm competition intensity (as measured by relative testis size) and (ii) female reproductive characters, across 15 species of beetle belonging to the family Bruchidae. 3. Stepwise multiple regression within a phylogenetic framework revealed sperm length to be positively correlated with female spermathecal duct length and negatively related to spermathecal volume, but not testes size, indicating that the female reproductive environment rather than sperm competition per se exerts selection on sperm length in this taxonomic group. 4. A positive association between testes volume and the volume of the female spermatheca was also evident suggesting correlated evolution of these traits. 5. A number of models of sexual selection could lead to the correlated evolution of male and female reproductive characters, although the underlying mechanisms of cause and effect remain elusive. Divergence between species (and populations) in primary reproductive traits is likely to present a significant barrier to hetero-specific fertilization, and thus contribute to reproductive isolation. [ABSTRACT FROM AUTHOR]

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Abstract: The effects of male-derived extracts on female receptivity to remating were investigated in Callosobruchus chinensis (Coleoptera: Bruchidae). Injection of aqueous extracts of male reproductive tracts into the abdomen of females reduced receptivity. When aqueous extracts of male reproductive tracts were divided to three molecular weight (MW) fractions by ultrafiltration: <3, 3–14, and >14kDa, the filtrate containing MW substances <3kDa reduced female receptivity 3h and 1 day after injection, whereas the fraction containing MW substances >14kDa inhibited receptivity 2 and 4 days after injection. Finally, male reproductive tract organs were divided into accessory gland, seminal vesicle, and testis. Aqueous extracts of testis reduced receptivity of females on the second day and at 3h, and aqueous extracts of accessory gland reduced receptivity of females on the second day after injection. On the other hand, aqueous extracts of seminal vesicle did not reduce female receptivity. The results indicate that more than one mechanism may be involved in producing the effects of male-derived substances on female receptivity; low MW male-derived substances, which possibly exist in testis, cause short-term inhibition, while high MW substances, which possibly exist in the accessory gland, inhibit female mating later than low MW substances in C. chinensis. [Copyright &y& Elsevier]

The influences of both predator density and elapsed time between initial infestation and introduction of predators were determined for suppression of bruchids infesting stored grain legumes by Xylocorisflavipes (Reuter) (Hemiptera: Anthocoridae). Predator density treatments consisted of zero, one, two, three, or five male:female pairs of adult X. flavipes added to experimental arenas 0,24, or 120 h after bruchid introduction. Suppression of Acanthoscelides obtectus approached eradication with all predator treatments. For all other bruchid species evaluated (Callosobruchus analis, C. chinensis, C. maculatus, and Zabrotes subfasciatus) , the most effective predator density and addition time (five predator pairs at 0 h) resulted in an ~50% reduction of emerging F1 bruchids compared with progeny produced in arenas without predators. The predator addition time of Oh, when predators were added to experimental arenas simultaneously with the pest species, was determined to be the universally most efficacious treatment time. Predator density above one pair but lower than five pairs was less influential overall when X. flavipes was added 24 or 120 h after initial bruchid infestation; however, maximum suppression was achieved at approximately two predator pairs and not significantly improved on with increased predator density. Our results indicate that the most effective biological control of pest bruchids would occur when X. Jiavipes is added as soon as possible after legumes are stored. [ABSTRACT FROM AUTHOR]

Bruchid, Callosobruchus spp. (Coleoptera: Bruchidae), is a serious pest during storage of seeds of mungbean ( Vigna radiata (L.) Wilczek) and other Vigna species. A source of resistance to this pest has been identified in Vigna sublobata (Roxb.) Bairig. accession TC1966 . Two hundred recombinant inbred lines at the F12 generation have been developed for molecular mapping of bruchid resistance ( Br) gene in TC1966. Through bulked segregant analysis (BSA), ten randomly amplified polymorphic DNA (RAPD) markers associated with the bruchid resistance gene were successfully identified. A total of four closely linked RAPDs were cloned and transformed into sequence characterized amplified region (SCAR) and cleaved amplified polymorphism (CAP) markers. Seven CAPs developed from the identified RAPD markers showed tighter linkage with the Br gene than the original RAPD. Through transformation of RAPDs into CAPs, codominant markers for bruchid resistance were successfully obtained. Homozygous genotypes of these PCR-based markers were estimated to contribute 85% of the variance for seed damage when the insect assay was performed under favorable growth conditions for bruchid. [ABSTRACT FROM AUTHOR]

Bruchid beetles or seed weevils are the most devastating stored pests of grain legumes causing considerable loss to mungbean ( Vigna radiata (L.) Wilczek). Breeding for bruchid resistance is a major goal in mungbean improvement. Few sources of resistance in cultivated genepool were identified and characterized, however, there has been no study on the genetic control of the resistance. In this study, we investigated the inheritance of seed resistance to Callosobruchus chinensis (L.) and C. maculatus (F.) in two landrace mungbean accessions, V2709BG and V2802BG. The F1, F2 and BC generations were developed from crosses between the resistant and susceptible accessions and evaluated for resistance to the insects. It was found that resistance to bruchids in seeds is controlled by maternal plant genotype. All F1 plants derived from both direct and reciprocal crosses exhibited resistance to the bruchids. Segregation pattern of reaction to the beetles in the F2 and backcross populations showed that the resistance is controlled by a major gene, with resistance is dominant at varying degrees of expressivity. Although the presence of modifiers was also observed. The gene is likely the same locus in both V2709BG and V2802BG. The resistant gene is considered very useful in breeding for seed resistance to bruchids in mungbean. [ABSTRACT FROM AUTHOR]

Abstract: The insecticidal activity of crude essential oil extracted from Cymbopogon schoenanthus and of its main constituent, piperitone, was assessed on different developmental stages of Callosobruchus maculatus. Piperitone was more toxic to adults with a LC50 value of 1.6 μl/l vs. 2.7 μl/l obtained with the crude extract. Piperitone inhibited the development of newly laid eggs and of neonate larvae, but was less toxic than the crude extract to individuals developing inside the seeds. [Copyright &y& Elsevier]

The nut and shell of cashew ( Anacardium occidentale L.) were evaluated for insecticidal efficacy at concentrations of 2.5, 5.0 and 7.5% per 150 g bambarra groundnut ( Voandzeia subterranea L.) Verde seeds against Callosobruchus subinnotatus (Pic.) (Bruchidae). Cashew nut shell was highly toxic to C. subinnotatus and achieved 100% insect mortality within 48 hours at 7.5% and 100% mortality within 72% hours at 2.5 and 5.0% concentrations. Oviposition and progeny development of the insect were severely suppressed while seeds were protected from damage by the bruchid. Seed germination was, however, impaired at all concentrations, suggesting that seed treated with cashew products may be suitable for consumption but not be suitable as planting stock. [ABSTRACT FROM AUTHOR]

Male Callosobruchus chinensis (Coleoptera: Bruchidae) have elaborated, pectinate antennae, which are absent from conspecific females and both sexes of a congener, Callosobruchus maculatus. To begin to unravel the mechanisms producing this striking dimorphism, we examined which morphological traits best explain body size variation in bruchid beetles and quantified sexual dimorphism of antenna size through allometric analyses. Using principal component analyses, we found that elytron length and pronotum width were significantly correlated with the first principal component, which was interpreted as explaining variation in body size. Regressions of log-transformed body size measures on log-transformed antenna length revealed that males of both species had longer antennae than conspecific females for any given body size, although most of this effect was attributable to higher intercepts, rather than increased allometry, in males. Comparisons among heterospecific males revealed that C. maculatus males have noticeably longer antennae than C. chinensis males at large body sizes. Callosobruchus chinensis males, thus, appear to have increased the receptive area of their antennae by adding to the width of, rather than further elongating, their antennae. Finally, we found evidence for positive allometry between log-transformed antenna length and log-transformed antenna width in C. chinensis males. We discuss our results in the context of evidence supporting the presence of an additional, and potentially unique, sex pheromone in C. chinensis females. [ABSTRACT FROM AUTHOR]

Control over copulation duration is a potentially important generator of sexual conflict that has received little empirical attention. The copulatory behavior of the bruchid beetle Callosobruchus maculatus may reflect a sexual conflict over copulation duration. Males have spines on their intromittent organs that puncture the female reproductive tract, and females kick their mates during copulation. If females are prevented from kicking, copulations last longer and the injuries females sustain are more severe. Males supposedly use the spines as anchors to prolong copulation duration, and females kick to terminate copulations. We manipulated copulation duration experimentally and quantified its effects on male and female fitness components to test whether or not there is a conflict over copulation duration in C. maculatus. Females did not suffer from long copulations but instead experienced increased lifetime fecundity. Ejaculate size increased with copulation duration, and females apparently derive material benefits from the ejaculates. Males that mated first and had long copulations were relatively unsuccessful when competing with sperm from other males. However, there was a trend for female remating propensity to decrease with long copulation durations, and first males may therefore also benefit from long copulations. The copulation duration of the second male to mate did not have a significant effect on sperm precedence. We conclude that even though it seems likely that the male spines have evolved to act as an anchor during copulation, there seems to be little conflict over copulation duration per se in C. maculatus. [ABSTRACT FROM AUTHOR]

Theoretical and empirical studies of life history assume that egg size and number cannot be maximized simultaneously because of a trade-off between them. In many empirical studies, however, only egg size or egg number was examined as a fitness component of the mother. We estimated phenotypic and genetic correlations between egg size and number, and heritabilities of each trait by half-sib analysis in Callosobruchus chinensis (L.) (Coleoptera: Bruchidae). The signs of all genetic correlations between egg size and egg number were negative, but near zero and not significantly different from zero. The result means that no trade-off was found between egg size and egg number, at least in this beetle population. We discuss three reasons (i.e., laboratory adaptation, mutation, and resource acquisition ability) why we did not detect a significant negative genetic correlation between egg size and egg number even when genetic trade-off existed. [ABSTRACT FROM AUTHOR]

The sympatric bruchids Callosobruchus rhodesianus (Pic) and Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) colonize cultures of cowpea, Vigna unguiculata (Walp.) (Papilionaceae), in Togo at the end of the rainy season. Seeds containing larvae of the two bruchid species were introduced into the storage systems. Callosobruchus rhodesianus adults emerged from the seeds at the beginning of storage, but this species disappeared quickly and C. maculatus became dominant. Analysis of the reproduction of females collected at the beginning of storage made it possible to distinguish between four groups of females differing in their reproductive activity. Three groups were sexually active but they differed in their fecundity and the duration of the latency period before the first oviposition phase. The fourth group of females was in reproductive diapause. In interspecific competition, the presence of C. maculatus larvae reduced the survival chances of C. rhodesianus and therefore is disadvantageous for this species. The main factors explaining the rapid decrease of the C. rhodesianus populations under storage conditions were the variability of female reproductive activity with the emergence of insects in reproductive diapause and the significant larval mortality in interspecific competition with C. maculatus. [ABSTRACT FROM AUTHOR]

The evolution of polyandry remains controversial. Various hypotheses that account for its evolution assume heritable variation in polyandry. We compared the frequency of female remating in 10 strains of the adzuki bean beetle, Callosobruchus chinensis, then made crosses between populations of high and low remating frequencies to investigate the mode of inheritance of polyandry. We found significant heritable variation in polyandry between the strains. Lower levels of polyandry were found in populations derived from long-term laboratory cultures than in those from recently established ones, suggesting that a selection pressure favoured monandry in the laboratory cultures. F1 offspring from reciprocal crosses between strains with high and low frequencies of female remating had frequencies similar to that of the strain with a high remating frequency, suggesting that polyandry is inherited with dominance in C. chinensis, unlike any other species reported to date. This study indicates that polyandry can evolve in response to selection in C. chinensis. [Copyright &y& Elsevier]

We describe a robust and reproducible Agrobacterium-mediated chickpea transformation method based on kanamycin selection, and its use to introduce the bean αAI1 gene into a desi type of chickpea. Bean αAI1 was specifically expressed in the seeds, accumulated up to 4.2% of seed protein and was processed to low molecular weight polypeptides as occurs in bean seeds. The transgenic protein was active as an inhibitor of porcine α-amylase in vitro. Transgenic chickpeas containing α-AI1 strongly inhibited the development of Callosobruchus maculatus and C. chinensis (Col. : Bruchidae) in insect bioassays. [ABSTRACT FROM AUTHOR]

Callosobruchus maculatus has both contest and scramble competition strategies. The currently existing theoretical models using game theory suggest that the contest strategy should be selected for. However, most geographic strains of C. maculatus show scramble competition. We experimentally crossed the representative strains of contest and scramble. We expressed the degree of contest competition by a continuous value named the C-value, which ranges from zero (pure scramble) to unity (pure contest). The competition types expressed in the C-value were genetically additive. Their larval developmental rates were negatively correlated with C-values. Multiple-generation experiments of the mixed strains confirmed that there were no overwhelming advantages of contest over scramble type. Most of the mixed strains remained in the intermediate states. We discuss the results in terms of the resource size necessary for developmental success and developmental speed. [ABSTRACT FROM AUTHOR]

The Sn-Glycerol-3-phosphate dehydrogenase (GPDH: NAD+ 2-oxidoreductase, EC1.1.1.8) gene of C chinensis was cloned and its nucleotide sequence was analyzed. The gene was obtained by screening a genomic library with Drosophila melanogaster Gpdh and PCR amplification. The 5,126 bp gene obtained is comprised of one 5′ untranslated region, eight exons, seven introns, and three 3′ untranslated regions. Comparison of Gpdh of D. melanogaster with that of C chinensis showed a 89.9% identity in the coding region, 70% in the intron, 79% in the entire nucleotide sequence, and 83.2% in the deduced amino acid sequence. The transcription initiation site is located 33 nucleotides upstream of the initiation codon, and the sequence analysis of the promoter region showed TATA and CAAT boxes at the 5′ end. The stop codon (TAA) and polyadenylation signal (AATAAA) are located at the 3′ end of each of the exons 6 to 8. These Findings show that GPDH isozymes in C. chinensis are produced by the alternative processing of 3′ exons. The occurrence of the three transcripts was proven by RT-PCR using synthetic oligonucleotides complementary to the predicted unique 3′ regions. Compared to the D. melanogaster GPDH isozymes, GPDH-1, -2, and -3, C chinensis GPDH showed 83.6%, 83%, and 84% identities, respectively. [ABSTRACT FROM AUTHOR]

A mungbean (V. radiata) line (BC[sub3]F[sub3] generation) which is resistant to two species of bruchid beetles (Callosobruchus chinensis and C. maculatus) was successfully developed in Thailand using a wild mungbean variety (V. radiata var. sublobata). One accession (TC1966) of wild mungbean was found to be completely resistant to C. chinensis and C. maculatus occurring at Chainat Field Crops Research Center in Thailand. The resistance was controlled by a single dominant gene (R). A breeding program to develop a bruchid-resistant mungbean cultivar with good agronomic characters under the environmental conditions of Thailand was initiated in 1987. 'Chainat 60' ('CN60'), a recommended mungbean cultivar in Thailand, was crossed with TC1966 to incorporate the resistance gene. Agronomic characters of the hybrids were improved by recurrent backcrossing using 'CN60' as a pollen parent. Seed yield per plant, days to flowering, and seed size of the bruchid-resistant BC[sub3]F[sub2] population reached the level of 'CN60' after three consecutive backcrossings. Bruchid-resistant line (BC[sub3]F[sub3], R/R) was selected from individual BC[sub3]F[sub2] plants. [ABSTRACT FROM AUTHOR]

Mating and oviposition behaviors were studied in Callosobruchus subinnotatus. Copulation was most frequent during the late scotophase, 2–3 h before onset of photophase. The females were less willing to mate during photophase, which increased the time to initiate mating while decreasing the duration of mating. Females exhibited increased movement prior to mating, resting immediately after mating, and remained stationary for 6 h when oviposition commenced. Multiple mating by both males and females affected the number of eggs laid, duration of mating, and uncoupling time at the end of mating. Females that mated two or three times laid more eggs than females that mated once or more than three times. Females that remained in copula for less than 18 min showed greater readiness to remate than those that remained in copula longer. There was a gradual decrease in the number of eggs females could lay with an increase in the number of previous matings by males. [ABSTRACT FROM AUTHOR]