Search

A morphological study is carried out on the taxonomic characters of the species of the genus Bruchidius Schilsky, 1905, grouped in the bimaculatus subgeneric group, present in the Iberian Peninsula (Spain and Portugal), the Balearic Islands, and the Canary Islands. The morphological characters and their value as a discriminating criterion of the species of the group are analyzed, as well as the concordant and discordant aspects of the known trophic biology of the different species. [ABSTRACT FROM AUTHOR]

A morphological study is carried out on the taxonomic characters of the species of the genus Bruchidius Schilsky, 1905, grouped in the foveolatus subgeneric group, present in the Iberian Peninsula (Spain and Portugal), the Balearic Islands, and the Canary Islands. The morphological characters and their value as a discriminating criterion of the species of the group are analyzed, as well as the concordant and discordant aspects of the known trophic biology of the different species. [ABSTRACT FROM AUTHOR]

A study on the taxonomic characters that have been used to discriminate the different species of the genus Bruchidius included in the unicolor group, represented in the Iberian-Balearic and Canary Islands fauna, is carried out. The taxonomic and biological heterogeneity of the species included in this group is discussed and some criteria are provided for characterization according this heterogeneity. The morphological analysis concludes with the low taxonomic value of its characters to differentiate the species, requiring the use of a set of characters. [ABSTRACT FROM AUTHOR]

A detailed and illustrated description of Bruchidius misellus (Boheman, 1833), is offered, being a poorly known species, which has always been considered as a variety of other species of the unicolor group, but currently there is scientific consensus in considering it as a good species, with distribution restricted to a few countries of the Western Mediterranean, including those of the Iberian Peninsula. [ABSTRACT FROM AUTHOR]

A study on the taxonomic characters that have been used to discriminate the different species of the genus Bruchidius included in the varius group, represented in the Iberian-Balearic and Canary Islands fauna, is carried out. The taxonomic and biological heterogeneity of the species included in this group is discussed and some criteria are provided for characterization according to this heterogeneity. [ABSTRACT FROM AUTHOR]

Knowledge about biology of seed beetles (Coleoptera, Bruchidae) is scarce or non-existent in the vast majority of species of no economic interest. Data on trophic biology are confusing, mixing host species with refuge species. In recent years, an effort has been made to understand the biology of these insects, based on in vivo information. In this article we present observations on the trophic and reproductive biology of six species of the genus Bruchidius, made in the course of these studies. [ABSTRACT FROM AUTHOR]

Fruit and seed predators determine plant populations dynamics and community structure of tropical forests. Its impact can have drastic consequences on the development of plants and their ability to reproduce. Among the main causes of damage to fruits, and seeds, Coleoptera of the Curculionidae and Bruchidae families and other groups of beetles stand out. The research was carried out in the Metropolitan Natural Park (PNM), considered as the "lung of the City of Panama" which has deciduous trees that reach up to 36 m in height and an average annual temperature of 28° C. The work consisted of collecting samples of fruits and seeds of all plant species encountered in the fruiting condition in the park from August 2015 to July 2016. Additionally, flower buds of Anacardium excelsum L. attacked by two species of Anthonomus Germar, 1817 were also included in the analyses. A total of 797 beetles were collected from 3091 samples (seeds, fruits, flower buds) reared at environmental conditions. The Curculionidae and Bruchidae families presented the highest abundance of individuals and species richness. One species of Hypothenemus Westwood, 1836 (Scolytinae), was the most abundant within the Curculionidae family and in the Bruchidae family one species of Acanthoscelides Schilsky, 1905. Tree species such as Oenocarpus mapora H. Karst. 1857 and Guazuma ulmifolia Lam presented higher predation of their fruits or seeds. On average only 5% of dissected seeds were predated across 32 host plant species. In total, 31 genera of beetles were reared from flower buds, seeds, and fruits of 17 plant species. Host-specificity was moderated, with 47% of flower bud, fruit and seed predator genera associated with just one plant species. Sixty one percent of the coleopterans were collected in the dry season (December to March). [ABSTRACT FROM AUTHOR]

A study on the taxonomic characters that have been used to discriminate the different species of the genus Bruchidius included in the seminarius group, represented in the Iberian-Balearic and Canary Islands fauna, is carried out. The taxonomic and biological heterogeneity of the species included in this group is discussed and some criteria are provided for characterization according to this heterogeneity. [ABSTRACT FROM AUTHOR]

A study of the morphological characters of the genus Bruchus with taxonomic value is carried out, and the degree of coincidence of these characters between the species of each of the subgeneric taxonomic groups of the genus Bruchus is analyzed, noting that these taxonomic groups present excepcional morphological characters that are not shared by some of the species of each group, except for the characters of the male genitalia. [ABSTRACT FROM AUTHOR]

Se describen aquí los caracteres bionómicos y morfológicos de las etapas preimaginales de Amblycerus caryoboriformis (Pic), Sennius laminifer (Sharp) y Stator bisbimaculatus (Pic), tres especies de Bruchidae comúnmente encontradas en el noroeste de Argentina. También se da la morfología de los adultos de A. caryoboriformis y S. bisbimaculatus. Se comparan los resultados con los ya conocidos de otras especies del mismo género y con otros grupos de la familia mencionada.

Se investigaron los cromosomas meióticos de 20 machos de Scutobruchus cassiovorus y 20 machos de Merobruchus bicoloripes para determinar su constitución cromosómica. Los cariotipos encontrados fueron: 2n = 18, n = 8Xyp para Scutobruchus cessiovorus y 2n = 24, n = 11Xyp, para Merobruchus bicoloripes. Se analizan las diferencias numéricas y estructurales entre ellos y otras especies de Bruchinae.

En este artículo se describe la morfología de la primera y madura larva y el ciclo de vida de Amblycerus longesuturalis (Pic). También se proporcionan nuevos estudios de morfología del adulto.

A preliminary catalog of seeds beetles (Coleoptera: Bruchidae) from the Autonomous Community of Madrid (Spain) is presented. After the study of about 300 specimens, mostly from the National Museum of Natural Sciences of Madrid, a total of 41 species of seed beetles were obtained, included into six genera, of which the most numerous were the genus Bruchidius (with 21 species) and the genus Bruchus (with 13 species), representing approximately 45,2 % of the Iberian-Balearic fauna of this group of Coleoptera. [ABSTRACT FROM AUTHOR]

A study is carried out on the reliability of the morphological characters attributed to Pseudopachymerina grata (Terán, 1990) for its differentiation from Pseudopachymerina spinipes (Erichson, 1833) species concluding that, given the great variability of characters such as the female pigidian spot pattern or the number of denticles of the pecten of the metafemur, these characters are not valid to differentiate both species. The male's genitalia is the only character that allows the two species to be safely differentiated. [ABSTRACT FROM AUTHOR]

From the available bibliographic data, as well as the inventories of species of various collections, all of them collected in the database of BRUCOL, of the Postgraduate College, México, an annotated checklist of species of seed beetles (Coleoptera, Bruchidae) from Bolivia has been prepared. As a result, a list of 95 species of seed beetles is showed, of which 21 species are new records to the currently known Bolivian fauna. Collaterally, this study also detected 23 new records for various countries in America. Moreover, distribution data is offered, which shows the existence of five potentially endemic species of Bolivia and a fauna close to the Brazilian. Finally, a list of host plants of each species is offered, obtaining 11 new host records for some species; in general, the bruchid species presented a predominantly monophago-oligophage trophic regimen in its different grades. [ABSTRACT FROM AUTHOR]

A review of the Pachymerinae subfamily reported in the geographical area of the Iberian Peninsula, Balearic Islands and Canary Islands has been done. The result is the registration of four species of this atypical subfamily in this study area. Keys for their species differentiation are shown, as well as a detailed description of each of these species that make up this subfamily, three of them from the Caryedontini tribe, genus Caryedon Schoenherr, and a fourth from the Pachymerini tribe, genus Caryobruchus. Of the Caryedon species, we find one (C. gonagra) in the Canary Islands, established in Tamarindus indica, and two indicated in the Iberian Peninsula, of which one (C. acaciae) is established, living in the invading Acacia karoo, and the other (C. serratus) only corresponds to old interceptions in Arachys hypogea seeds, not established in this area. As for the only species of Caryobruchus (C. gleditsiae) only one specimen has been found, supposedly associated with the Sabal palmetto palm tree planted in the Palmetum park in Tenerife (Canary Islands). [ABSTRACT FROM AUTHOR]

During a taxonomic study on tree borers in Egypt, three beetles of them were recorded for the first time in Egypt. They were Bostrychoplites sp. and Heterobostrychus equalis (Waterhouse, 1884) belonging to family Bostrichidae and Acanthoscelides macrophthalmus (Schaeffer, 1907) belonging to family Bruchidae. In this study illustrated description of these species were given with the collecting date, location and host plant. [ABSTRACT FROM AUTHOR]

A detailed description of the species Bruchidius steveni (Gyllenhal, 1839), a little known coleopteran of family Bruchidae, allocated in Central Asia, is offered, confirming its location in Kirguistán, and recording into Tayikistán for the first time. Observations on the distribution area today known and his potencial area, is argued. [ABSTRACT FROM AUTHOR]

The research tackles the taxonomy of six insects genera:Caryedon, Spermophagus, Bruchus, Bruchidius, Callosobruchus and Acanthoselides that belong to Bruchidae family :Coleoptera order which are recorded in Iraq depending on morphological characteristics which were given suitable code for numerical analysis by using clustering analysis statistically packaging SPSS-17. The results were compared by computer to manifest different kinship relations. The results manifest that the relation percentage of phylum is 97% on basis of the degree of similarity of morphological characteristics between Bruchus and Bruchidius genera; and between Caryedon and Spermophagus genera, whereas the kinship relation between the former two genera and the latter two is 72%, its reveals that Callosobruchus and Acanthoselides genera have less degree of relation 27% in this family in Iraq. By using diagrams of multisided popular relation tree it appears that popular relation of the four genera Bruchus, Bruchidius,Caryedon and Spermophagus have no kinship relation with the two genera Callosobruchus and Acanthoselides i.e. 0%. [ABSTRACT FROM AUTHOR]

As a contribution to the knowledge of de entomological fauna of Grecia, a catalog of seed beetles (Coleoptera: Bruchidae) collected in the years 2005 and 2007 in Greece by Fernando Angelini, is presented. It compiled a total of 1.704 specimens corresponding to 63 species of Bruchidae, of which have been 4 species of the genus Spermophagus, 38 species of Bruchidius, 2 species of Serratobruchidius, and 19 species of Bruchus. This catalog confirms the records in Greece of previous authors, considerably increasing the number of localities, and adding, as new records for this country the following 4 species: Bruchidius corsicus (Baudi, 1890); Bruchus brisouti Kraatz, 1868; B. griseomaculatus Gyllenhal, 1833, y B. sibiricus Germar, 1824. [ABSTRACT FROM AUTHOR]

In the absence of consensus in the application of the terminology used to qualify the trophic regime of the different species of seed beetles (Coleoptera, Bruchidae), there being no precision or scientific consensus between the concepts of monofagy, oligophagy and polyphagy, in this article a proposal is made to systematize these terms based on the taxonomic distance of their known host plants, expanding the categories with three more degrees for each term, totaling nine categories of inaccurate limits, but of greater precision than hitherto. An application is presented for the case of the check-list of the Bruchidae of Peru [ABSTRACT FROM AUTHOR]

Descriptions of three new species in the genus Bruchidius Schilsky, 1905 are presented. Bruchidius nepalensis sp. nov. from Nepal and B. tricolor sp. nov. from India, Laos and Thailand are assigned to the Bruchidius japonicus species-group, while B. planicornis sp. nov. from Iran and Turkey is assigned to the Bruchidius astragali species-group. Detailed fi gures of antennae and genitalia are given. [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.

Biological control of bruchid beetles, Callosobruchus maculatus ( Fabricius) ( Coleoptera: Bruchidae), infesting cowpea seeds, Vigna unguiculata ( L.) Walpers ( Fabaceae), can be performed via augmentative releases of Dinarmus basalis Rondani ( Hymenoptera: Pteromalidae) parasitoid wasps. Females of the latter species are therefore likely to experience intense intraspecific competition: they should encounter numerous previously parasitized hosts but also conspecific competitors, with which they may fight to secure hosts on which to lay their eggs. Such contests might therefore disrupt biological control programs. Here, we studied aggressive behavior that D. basalis females show toward conspecific competitors and subsequent host exploitation strategies. We further investigated factors that classically affect contest intensity and outcomes in animals, such as the effect of ownership status, by manipulating the residency period before the intruder's arrival. In addition, we tested the effect of the size of female reproductive tissue (measured in terms of egg load) and the quality of the habitat previously experienced by females (either rich or poor in hosts). These two factors are expected to influence the value that females place on the host and therefore the costs they are willing to pay to win it. Finally, we discussed the consequences of agonistic behaviors on females' host exploitation strategies. Our results suggest that contest competition may actually enhance host control by favoring parasitoid dispersion, rather than disrupting it. [ABSTRACT FROM AUTHOR]

Whether alien insects that are introduced into temperate regions adapt to seasonally changing environmental conditions is an important question in evolutionary biology. If rapid evolution has occurred in a non-native environment, a latitudinal cline in critical photoperiod for diapause induction (i.e., the photoperiod at which half of the individuals enter diapause) and in life cycle synchronization with host plant phenology should be evident among locations. The alien bruchid Acanthoscelides pallidipennis (Motschulsky) (Coleoptera: Bruchidae) is native to North America and introduced into Japan with the host plant Amorpha fruticosa L. (Fabaceae) in the late 1940s. To examine whether seasonal adaptation has occurred in A. pallidipennis, we conducted a laboratory experiment and phenological observations using three latitudinally different populations. We bred F1 eggs at 22 °C and five photoperiodic regimens - L:D = 10:14, 13:11, 14:10, 15:9, or 16:8 hours - and examined whether diapause was induced. The estimated critical photoperiod for diapause induction was longest in the most northern population and shortest in the most southern population. Life cycle was found to be synchronized with host phenology in each location. Also voltinism varied geographically, from univoltine in the northern population to bivoltine in the southern populations. These results showed that A. pallidipennis rapidly adapted to seasonal environmental conditions in Japan after its introduction. [ABSTRACT FROM AUTHOR]

Inbreeding depression of an aspect of fitness is observed in many insects, but the traits that are of importance for inbreeding depression of fitness remain poorly understood. Here the magnitude of inbreeding depression of fitness-related traits in the development and adult stages was measured in a captive population of the adzuki bean beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). Beetles produced by full-sib matings had 8% lower survival in the development stage than did beetles produced by unrelated matings. Although inbred and outbred offspring did not differ in body size after emergence, inbred offspring took 2-3% longer to develop to emergence. This indicates inbreeding depression of growth rate. At the adult stage, inbreeding had no significant effect on longevity, however lifetime offspring production was reduced by 11%. Thus, the magnitude of inbreeding depression was relatively large for offspring production. This suggests inbreeding depression of fitness manifests, to a particularly significant extent, in reduced productivity. This study shows the C. chinensis population, which has been in captivity for more than 100 generations, harbors genetic loads. [ABSTRACT FROM AUTHOR]

Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae) is a cosmopolitan pest of stored pulses and legumes. Under legume storage conditions neither adults nor larvae drink, with larvae obtaining their hydration from metabolic water. However, lack of water limits female fecundity and longevity, thus females might be expected to preferentially oviposit on seeds with high moisture content so as to minimize water stress on their offspring. This was tested by offering females a choice of seeds that differed in relation to their level of water content. After controlling for differences in seed size, females were found to preferentially oviposit on the driest seeds. Offspring size and larval survival were equivalent on seeds that differed in moisture content, which in combination with the preference to lay on the driest seeds would indicate that the egg laying decisions of C. maculatus females do not function to minimize larval water stress. Analysis of the chemical volatiles released by seeds that differed in their moisture content revealed a greater level ofd-limonene in the environment surrounding high moisture seeds.d-limonene has known anti-herbivory properties, thus we suggest the observed female preference for dry seeds may be related to the observed difference in the level ofd-limonene in the immediate vicinity of beans that differ with respect to their moisture content. [ABSTRACT FROM AUTHOR]

The inventory of the leaf and seed beetles alien to Europe revealed a total of 25 species of which 14 seed beetles (bruchids) and 11 leaf beetles mostly belonging to the subfamilies Alticinae and Chrysomelinae. At present, aliens account for 9.4% of the total fauna of seed beetles in Europe whereas this percentage is less than 1% for leaf beetles. Whilst seed beetles dominated the introductions in Europe until 1950, there has been an exponential increase in the rate of arrival of leaf beetles since then. New leaf beetles arrived at an average rate of 0.6 species per year during the period 2000-2009. Most alien species originated from Asia but this pattern is mainly due to seed beetles of which a half are of Asian origin whereas leaf beetles predominantly originated from North America (36.4%). Unlike other insect groups, a large number of alien species have colonized most of Europe. All but one species have been introduced accidentally with either the trade of beans or as contaminants of vegetal crops or stowaway. Most aliens presently concentrate in man-made habitats but little affect natural habitats (<6%). Highly negative economic impacts have been recorded on stored pulses of legumes and crops but very little is known about possible ecological impact. [ABSTRACT FROM AUTHOR]

The article presents a study which evaluates the resistance of chickpea Cicer arietenum genotypes to pulse beetle Callosobruchus maculates in Turkey. It states that the chickpeas resistance which is tested in 11 chickpea genotypes such as desi chickpeas' ICC 14366 and kabuli's ICC 8617 were assessed by measuring the percent damage to the seeds. Results show that the desi chickpea is more resistant than Kabuli to the C. maculatus and the ICC 4969 genotypes is a source of resistant to C. maculatus.

The optimal number of mating partners for females rarely coincides with that for males, leading to sexual conflict over mating frequency. In the bruchid beetle Callosobruchus maculatus, the fitness consequences to females of engaging in multiple copulations are complex, with studies demonstrating both costs and benefits to multiple mating. However, females kept continuously with males have a lower lifetime egg production compared with females mated only once and then isolated from males. This reduction in fitness may be a result of damage caused by male genitalia, which bear spines that puncture the female’s reproductive tract, and/or toxic elements in the ejaculate. However, male harassment rather than costs of matings themselves could also explain the results. In the present study, the fitness costs of male harassment for female C. maculatus are estimated. The natural refractory period of females immediately after their first mating is used to separate the cost of harassment from the cost of mating. Male harassment results in females laying fewer eggs and this results in a tendency to produce fewer offspring. The results are discussed in the context of mate choice and sexual selection. [ABSTRACT FROM AUTHOR]

Many parasitic and endophagous insect species are capable of discriminating among the quality of their hosts. However, there is no appropriate way to quantify their discrimination performance. In this study, we quantified how oviposition of the cowpea seed beetle, Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae), was affected by the relative contributions of both egg number and host size discrimination. The effect of egg density and resource heterogeneity on these discrimination performances was also explored. Egg-distribution predictions were made by combining time-dependent available resource fitness (egg discrimination) and host weight factors (size discrimination). The χ2 test was then used for goodness-of-fit testing. The effects of both egg and size discrimination on oviposition in environments with different levels of resource heterogeneity were compared. It was found that host size, rather than the number of eggs on the host, plays a larger role in the egg-laying decision for most individual seed beetles, especially when egg density is high. Host size discrimination behavior was reinforced when the beetles experienced increasing resource heterogeneity, but the performance might reach a plateau. This is the first quantitative evaluation of the effect of host discrimination on egg-laying decisions of seed beetles. [ABSTRACT FROM AUTHOR]

Biological control may provide an affordable and sustainable option for reducing losses to pest Bruchidae in stored food legumes, a crucial source of human dietary protein. Previous investigations have focused primarily on the role of parasitism in bruchid biological control, while the potential of generalist predators has been comparatively unexplored. The true bug Xylocoris flavipes (Reuter) (Heteroptera: Anthocoridae) exhibited a Type II functional response to the majority of cosmopolitan bruchid species evaluated when data were fit to Holling's disc equation. A negative correlation was detected between mean pest species body weight and rate of predation. The rate of attack on adult prey was quite low but fairly consistent, with the larger-sized female predators generally more effective. The eggs and neonate larvae of Acanthoscelides obtectus Say (Coleoptera: Bruchidae) were the only accessible immature stages among all prey species examined; predation on A. obtectus eggs and larvae was higher than on any adult bruchids. Mean predator kill of A. obtectus immature stages was 40 first instars or 10–20 eggs per 24-h interval. Further investigation of the biological control potential of X. flavipes against pest Bruchidae is merited due to the predator's ability to kill adult stages of all prey species evaluated. [ABSTRACT FROM AUTHOR]

Abstract: Bruchid beetle larvae cause major losses in grain legume crops throughout the world. Some bruchid species, such as the cowpea weevil (Callosobruchus maculatus) and the Mexican bean weevil (Zabrotes subfasciatus), are pests that damage stored seeds. The Mediterranean flour moth (Anagasta kuehniella) is of major economic importance as a flour and grain feeder; it is often a severe pest in flour mills. Plant lectins have been implicated as antibiosis factors against insects. Bauhinia monandra leaf lectin (BmoLL) was tested for anti-insect activity against C. maculatus, Z. subfasciatus and A. kuehniella larvae. BmoLL produced ca. 50% mortality to Z. subfaciatus and C. maculatus when incorporated into an artificial diet at a level of 0.5% and 0.3% (w/w), respectively. BmooLL up to 1% did not significantly decrease the survival of A. kuehniella larvae, but produced a decrease of 40% in weight. Affinity chromatography showed that BmoLL bound to midgut proteins of the insect C. maculatus. 33kDa subunit BmoLL was not digested by midgut preparations of these bruchids. BmoLL-fed C. maculatus larvae increased the digestion of potato starch by 25% compared with the control. The transformation of the genes coding for this lectin could be useful in the development of insect resistance in important agricultural crops. [Copyright &y& Elsevier]

We studied the effect of larval host (two Convolvulus L. species, Convolvulaceae) on sexual size dimorphism and on the fitness consequences of adult feeding in the bruchid beetle Megacerus eulophus (Erichson) (Coleoptera: Bruchidae). Whereas Convolvulus chilensis Pers. occurs in low density in semiarid habitats, Convolvulus bonariensis Cav. occurs in less stressful environments and exhibits higher population density. Host plants neither differ in seed mass nor in seed nitrogen content, and there were no consistent host-associated differences in female fitness. Consequently, host quality was considered to be similar. Sexual size dimorphism, expressed as the female:male ratio of body size, was significantly greater in C. chilensis than in C. bonariensis. A greater female size in the C. chilensis population could be selectively advantageous due to higher survival during host-plant search in stressful environments. Female longevity was affected by food availability (starvation vs. honey-pollen solution) and by the interaction between food availability and larval host. Fed females lived longer than starved females. This trend was found in both hosts, but it was of greater magnitude in C. chilensis than in C. bonariensis. Fecundity was significantly affected by adult feeding and larval host, and marginally affected by their interaction. Fed females laid more eggs than starved females. However, the increase in fitness of fed females was greater in C. chilensis. Results might be explained by differential selection on plasticity in life-history traits in contrasting environments. Females in stressful environments should take a greater advantage of the transient availability of resources. [ABSTRACT FROM AUTHOR]

Acacia trees (Leguminosae) in the Negev desert of Israel are in substantial danger of extinction as a result of high mortality, caused by anthropogenically induced water stress and very low recruitment, which is highly negatively affected by bruchid beetle infestation. Intensive seed infestation (up to 97%) by bruchids on Acacia species in the Negev desert has been described. We hypothesized that water-stressed trees would be less able to produce secondary defense compounds in their seeds to decrease seed herbivory and hence suffer higher infestation. Thus, there should be a negative correlation between the beetle's fitness and the tree's physiological state. We further hypothesized the mechanism of the correlation to be maternal effects on beetle quality. Thus, beetles whose mothers were reared on seeds of trees in a poor state should have higher fitness, regardless of the quality of the seeds in which they were reared. We reared F1 generation Caryedon palaestinicus Southgate (Coleoptera: Bruchidae) in seeds of Acacia raddiana Savi (Leguminosae) trees in good and in poor physiological state. We then conducted a reciprocal infestation experiment enabling females to lay on seeds from both sources. We found maternal effects on offspring number but not on body mass. The major effect was the limited survival of maternal beetles on trees in good physiological state. However, contrary to our prediction, C. palaestinicus developing in seeds from Acacia raddiana in good physiological state had significantly higher body mass. [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]

Acanthoscelides obtectusSay is a bruchid species of Neotropical origin, and is specialized on beans of thePhaseolus vulgarisL. group. Since the domestication and diffusion of beans,A. obtectushas become cosmopolitan through human-mediated migrations and is now a major pest in bean granaries. Using phylogeographic methods applied to mitochondrial DNA (mtDNA) and nuclear microsatellite molecular markers, we show that the origin of this species is probably further south than Mesoamerica, as commonly thought. Our results also indicate thatA. obtectusand its Mesoamerican sister speciesAcanthoscelides obvelatus, two morphologically close species differing principally in voltinism, speciated in allopatry:A. obtectus(multivoltine) arising in Andean America andA. obvelatus(univoltine) in Mesoamerica. In contrast to Mesoamerica where beans fruit once yearly, wild beans in Andean America fruit year-round, especially in regions showing little or no seasonality. In such habitats where resources are continuously present, multivoltinism is adaptive. According to existing hypotheses, multivoltinism inA. obtectusis a new adaptation that evolved after bean domestication. Our data suggest the alternative hypothesis that multivoltinism is an older trait, adapted to exploit the year-round fruiting of wild beans in relatively aseasonal habitats, and allowedA. obtectusto become a pest in bean granaries. This trait also permitted this species to disperse through human-mediated migrations associated with diffusion of domesticated beans. We also show that diversity of Old WorldA. obtectuspopulations can be quite well explained by a single colonization event about 500 bp. Human-mediated migrations appear not to be rare, as our results indicate a second more recent migration event from Andean America to Mexico. [ABSTRACT FROM AUTHOR]

AcanthoscelidesSchilsky is a large genus of neotropical bruchid beetles, in which most species show host plant specialization.Acanthoscelides obtectusandAcanthoscelides obvelatusare two sibling species specialized onPhaseolusbeans, and are therefore considered pests. Up to now, the status of these two taxa has remained unclear, the few studies conducted having failed to elucidate whether these are two differentiated species or a single morphologically variable species. In addition,A. obvelatushas not been taken into account in the great majority of studies of bean bruchids. In this morphological and genetic study, we show thatA. obtectusandA. obvelatusare two‘true’ non-hybridizing species, which diverged about 22 Mya. Although the two species demonstrate only few morphological differences, we point out some diagnostic characters that enable their identification in the field. We also address a genetic method of differentiation of the two species, based on species-specific microsatellite loci. The strong morphological resemblance of these two species, despite their ancient divergence, may be the result of evolutionary stasis, which could be the consequence of stabilizing selection. Niche differentiation could enable the two species to coexist indefinitely. [ABSTRACT FROM AUTHOR]

The most popular hypothesis that explains host specialization in herbivorous insects assumes the presence of a genetic trade-off in larval performance across host plant species. We examined whether there is a genetic trade-off in preadult performance traits on two hosts in the bean weevil, Acanthoscelides obtectus Say (Coleoptera: Bruchidae). Well-established laboratory populations of A. obtectus were maintained on two plant species, one being the native host (bean) and the other a novel, unsuit- able host (chickpea). After 50 generations of laboratory rearing, preadult survival and development time on each host plant were compared between the two populations. A split-brood design was used to estimate cross-host genetic correlations in the two traits and to compare the populations in their patterns of genetic variation over the two plants. We detected a survival cost paid by A. obtectus on its native host for the increasing adaptation to the novel one, and a significant population x host interaction for survival. The host effect on survival was significant in the bean-adapted population. The additive genetic variances for survival and female development time were only expressed on the novel host, and the half-sib family mean correlations across hosts were zero for both traits in both populations. However, the sire x host interaction for survival was not recorded in either population, whereas the sire x host interaction and non-additive genetic variance for development time evolved during the selection on the novel host. [ABSTRACT FROM AUTHOR]

Abstract. 1. A study of host preference of four pairs of populations of the cowpea weevil Callosobruchus maculates was carried out. The pairs had different geographical origins. 2. One population of each pair had been maintained for about 110 generations on cowpea Vigna unguiculata , the other population had been maintained on mung bean V. radiata . Half of the tested females from each population were raised on cowpea and exposed to this host prior to the assay; the other half was raised on mung bean. This design permitted assessment of the relative contributions of geographical origin, recent host use in the laboratory, and individual experience, to variation in host preference. 3. Host preference was assayed by letting the females oviposit on an equal-weight mixture of cowpea and mung seeds; two experiments were performed six generations apart. 4. Both experiments revealed a strong effect of geographical origin: populations originating from Nigeria laid a much greater proportion (68–86%) of their eggs on cowpea than those originating from Uganda and Yemen (30–42%); those from Cameroon were intermediate (56–60%). These preferences were not affected consistently by about 110 generations of laboratory evolution on one or the other host, or by experience of individual females. 5. These results indicate considerable geographical variation in host preference, and suggest that host preference is behaviourally inflexible and evolutionarily conserved. [ABSTRACT FROM AUTHOR]

Abstract Studies on the protective effect of botanical products against pest insects have infrequently been extended to side-effects on natural enemies. Indirect effects of botanicals on the storability of seeds could occur through their possible negative impact on biological control agents. Four plant powders and six plant oils with a known effect on the cowpea beetle Callosobruchus maculatus (Fabr.) (Coleoptera: Bruchidae) were investigated for their effect on the beetles’ egg parasitoid Uscana lariophaga (Steffan) (Hymenoptera: Trichogrammatidae) and the larval parasitoid Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae). All treatments caused a decrease in parasitisation by U. lariophaga , and developing parasitoids of this species were affected by powders of Nicotiana tabacum (L.) and Tephrosia vogelii (Hook. f). In a two-choice situation using a linear olfactometer, U. lariophaga was repelled by most of the oils. In a no-choice situation, parasitisation by D. basalis was hampered by treatment with plant powders, but eggs that were laid developed normally. In a Y-tube olfactometer, this parasitoid did not discriminate between odours of untreated and plant-powder-treated beans. The powders of N. tabacum and T. vogelii had stronger negative effects on the two parasitoids than the powders of Azadirachta indica (Juss.) or Blumea aurita (DC). In samples collected from untreated traditional storage facilities, subsequently treated with plant powders in the laboratory, none of the treatments could prevent the increase in beetle numbers. At 24 days after treatment, most beetles had emerged from beans treated with powders of N. tabacum and T. vogelii . Parasitoids were affected by the botanical insecticides tested here, but the powders of A. indica and B. aurita may be compatible with biological control by D. basalis . [ABSTRACT FROM AUTHOR]

Abstract The bruchid beetle, Bruchidius dorsalis Fahraeus (Coleoptera: Bruchidae), has a multivoltine life cycle and shows geographical variation of overwintering stages in Japan. Our previous study found that B. dorsalis enters larval diapause in the final instar under short photoperiods. In cooler areas, we observed that most individuals overwinter in the final larval stage in diapause, whereas beetles at different developmental stages (non-diapausing young instars, diapausing instars, and adults) were overwintering in warmer areas. In this study, we investigated geographical variation in the photoperiodic response for induction of larval diapause at 20 °C (three populations) and 24 °C (two populations) to clarify the overwintering strategy of B. dorsalis . We observed that (1) diapause incidence at 20 °C changed sharply from ca. 100% to 0% with a change in photoperiod in all the populations, (2) critical photoperiod was longer at 20 °C in populations from cooler areas, and (3) critical photoperiod at 24 °C was shorter than at 20 °C and a fraction of the larvae did not enter diapause, even under short photoperiods. Overwintering stages estimated from these results were consistent with those actually observed in the field. This study indicates that the geographical variation of overwintering stages is likely to reflect adaptive diapause induction in each local environment. [ABSTRACT FROM AUTHOR]

The effect of alkane-growth induction of theentomopathogenic fungus Beauveria bassiana(Balsamo) Vuillemin (Deuteromycotina:Hyphomycetes), on the ability to kill the beanweevil Acanthoscelides obtectus Say(Coleoptera: Bruchidae), was tested. Adultinsects were sprayed with an 0.01% Tween 20aqueous suspension of 4 × 106 conidia/ml.The performance of fungi grown in complete agarmedium containing glucose as carbon source(FS0) was compared to that of alkane-grownfungi (FS1) with n-hexadecane as the onlycarbon source. Mortality increased ( p< 0.05) from 22 ± 4.5% to 44 ±11.4% at day 7, and from 26 ± 5.5% to 60± 7.1% 14 days after treatment withFS0 or FS1 respectively. The insectepicuticular hydrocarbons were analysed bycapillary gas chromatography (CGC); majorcomponents were saturated hydrocarbons, 27 to29 carbons in length. A variety ofmethyl-branched isomers of C27 were theprevailing structures, and nC27 was the majorstraight chain component. Whole insecthydrocarbons were qualitatively identical tothose of the epicuticular surface. Oleic,linoleic and palmitic acids accounted foralmost 88% of the fungal fatty acids,irrespective of the carbon source used forgrowth; however, the unsaturated/saturatedratio diminished markedly from 4.32(FS0) to 2.47 (FS1). These resultsindicate that alkane supplementation of culturemedia might be a tool to improve the virulenceof some mycoinsecticides. [ABSTRACT FROM AUTHOR]

Callosobruchus analis (F.) is considered an important pest in several countries in Africa, Asia and Oceania. It has been observed infesting seeds belonging to 15 Leguminosae genera, including peanut, bean, chickpea, pea, cowpea, and soybean. One of its main natural enemies is the parasitoid Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae), whose control efficiency has already been demonstrated in several studies. This paper records the occurrence of C. analis and its parasitoid, D. basalis, in stored soybean of the state of São Paulo, Brazil.Callosobruchus analis (F.) é uma praga de expressão econômica em diversos países da África, Ásia e Oceania. Já foi observado infestando sementes de espécies de leguminosas pertencentes a 15 gêneros, incluindo-se culturas como amendoim, grão-de-bico, feijão, ervilha, caupi e soja. Um de seus inimigos naturais mais importantes é o parasitóide Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae), cuja eficiência de controle já foi demonstrada em vários estudos. Neste trabalho registra-se a ocorrência de C. analis e de seu parasitóide, D. basalis, em grãos armazenados de soja no estado de São Paulo.

The cowpea seed beetle, Callosobruchus maculatus, will lay its eggs on many potential hosts and inert surfaces. Oviposition on glass beads is stimulated by coating them with individual fatty acids. Nevertheless, female beetles reject mung seeds less frequently than beads treated with either an extract of mung seeds or, especially, an extract of mung seeds plus oleic acid. The addition of oleic acid to the extract resulted in a change in the sequence of oviposition behavior, notably an increase in a raised body position indicative of hosts of low acceptability. Fatty acids are present in the epicuticular waxes of legume seeds; wax extract of mung bean contains 32.4% fatty acid and 14 alkanes, whereas a wax extract of chickpea contains 5% fatty acid and 18 alkanes. Thus, chickpea may be a less acceptable host for oviposition than mung bean because of physical differences and/or because of chemical differences, including a reduced total level of fatty acid or the high proportion of oleic acid it is reported to contain. It is concluded that an appropriate mixture of fatty acids in the epicuticular waxes stimulates oviposition but that an elevated level of oleic acid in conjunction with others is deterrent. [ABSTRACT FROM AUTHOR]

Acanthoscelides obtectus (Say) is one of the most damaging pests of kidney beans, Phaseolus vulgaris L. worldwide. However, aromatic plants from the families Lamiaceae, Lauraceae, Myrtaceae and Poaceae can protect kidney beans by direct or delayed insecticidal effect, through increased adult mortality and inhibition of beetle reproduction (both oviposition and adult emergence). The efficiency of hydrodistillated and intact plants from Thymus vulgaris and T. serpyllum, Mentha piperata, Rosmarinus officinalis, Satureia hortensis, Eucalyptus globulus, Laurus nobilis, Origanum vulgare, and Cymbopogon nardus was compared. For both extracts, Origanum vulgare had the best effect. The insecticidal effect was induced by more than the essential oils because no significant difference was noticed between distilled and intact plants extract. Inhibition of reproduction was particularly important. These results suggest that lipidic as well as non lipidic, allelochemicals, such as phenolics, or non-protein amino-acids, or flavonoids may be involved in the toxicity of aromatic plants to this beetle. [ABSTRACT FROM AUTHOR]

Six microsatellite loci were isolated from the bruchid Acanthoscelides obtectus Say (Coleoptera: Bruchidae). Each locus was polymorphic, with the number of alleles ranging from 3 to 18. We found high levels of within-population variation at most loci, with heterozygosities ranging from 0 to 0.75. Cross-species amplification of these loci was tested in two other species of the genus Acanthoscelides, A. obvelatus Bridwell and A. argillaceus Sharp. [ABSTRACT FROM AUTHOR]

Five microsatellite loci were isolated from the bruchid Acanthoscelides obvelatus Bridwell (Coleoptera: Bruchidae). Each locus was polymorphic, with the number of alleles ranging from two to 15. We found high levels of within-population variation at most loci, with heterozygosity ranging from 0.182 to 0.900. Cross-species amplification of these loci was tested in two other species of the genus Acanthoscelides, A. obtectus Say and A. argillaceus Sharp. [ABSTRACT FROM AUTHOR]