The Interplay Between Phenotypic Plasticity and Long‐Term Evolution in Shaping Life History Strategy in the Seed Beetle

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, unsuitable 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 × 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 × host interaction for survival was not recorded in either population, whereas the sire × host interaction and non‐additive genetic variance for development time evolved during the selection on the novel host.

Potential use of clove and cinnamon essential oils to control the bean weevil, Acanthoscelides obtectus Say, in small storage units

Effects of contact insecticides pirimifos-methyl and deltamethrin of Indian meal moth Plodia interpunctella Hbn. and Angoumois grain moth Sitotroga cerealella Oliv. in maize, and on bean weevil Acanthoscelides obtectus Say in beans were examined 6 and 18 months after treatment in laboratory environment. Using appropriate methods (EPPO and other), maize and bean were treated with recommended and double rates of the insecticide products: EC formulation of pirimifos-methyl and EC formulation and dust of deltamethrin. After 6 and 18 months, we examined the mortality of P. interpunctella larvae, and 5. cerealella and A. obtectus adults following 2,7 and 14 days of contact with the treated material. In Angoumois grain moth and bean weevil, the resulting progeny was monitored up to FI generation. Both insecticides achieved full mortality of P. interpunctella larvae on the 6-month-old deposit. On the 18-months-old deposit, the same result was achieved with deltamethrin dust (both rates), as well as with pirimifosmethyl and deltamethrin (EC formulation) at the double recommended rates. S. cerealella mortality was 100% for both insecticides and both deposit ages. Regarding A. obtectus, full mortality of adults was found after contact with pirimifos-methyl and deltamethrin dust, while deltamethrin liquid caused low mortality of bean weevil, especially the 18-months-old deposit. FI generation adults of Angoumois grain moth and bean weevil were found only on 18-months-old deposits of the recommended rates of deltamethrin dust and pirimifos-methyl. The tested contact insecticides can provide very long prevention and control of Indian meal moth and Angoumois grain moth in stored maize and bean weevil in stored beens.

The paper presents the positive results obtained by some pesticides applied against the bean weevil - Acanthoscelides obtectus Say, after a synthetic rewiew of the potential chemical methods which may be used in the chemical control of the insectes harmful to the stored bean seeds. The chemical control is realised treatments wits syntetic pyrethroid (permetrin, deltametrin) and organophosphoric insecticides (malation, pirimifos metil, fenitrotion and chlrorpirifos-metil).

A comparative study involving several leguminosae species was done in order to learn if Acanthoscelides obtectus Say, bruchid of kidney bean (P. vulgaris L.), might reproduce upon originally non‐host plants. Seven species of Leguminosae which have an economic incidence in developing countries were selected: P. vulgaris, Vigna unguiculata, Vicia faba, Lathyrus sativus, Pisum sativum, Cicer arietinum and Glycine max. Oviposition, ovocytes in retention, larval penetration and larval growth were observed. The larval development (penetration and growth) has been experimented with on two kinds of pierced and intact seeds. A. obtectus appears to be very well adapted to it host plant, P. vulgaris, as reproudction is the highest. However, it could also develop upon the other seeds tested except Glycine max, in which no emergence occurred. Different degrees of inhibition of reproduction, including total ovarian production and larval growth, were noted upon the others. The role of tegument and ailelochemicals or components within cotyledon wheat were discussed.

In this study, the presence of some species of the Bruchidae family, the effects of those species to the quality and quantity of the seeds, and the storage conditions were investigated in dried legume seeds taken from farmers stores in both Denizli and Usak Provinces. The study was carried out in 17 villages of 9 different towns of Denizli Province and in 23 villages of 6 different towns of Usak Province, between the years 2001 and 2002. Adults obtained from the damaged seeds were identified to belong to species of Callosobruchus masculatus (Fabricius), Acanthoscelides obtectus (Say) and Bruchus emarginatus Allard. It was determined that the average number of adults in both Denizli and Usak samples was highest in chickpea and bean in 500 gr sample.

Freshwater mussels are a species-rich group with biodiversity patterns strongly shaped by a life history strategy that includes an obligate parasitic larval stage. In this study, we set out to reconstruct the life history evolution and systematics in a clade of freshwater mussels adapted to parasitizing a molluscivorous host fish. Anchored hybrid enrichment and ancestral character reconstruction revealed a complex pattern of life history evolution with host switching and multiple instances of convergence, including reduction in size of larvae, increased fecundity, and growth during encapsulation. Our phylogenomic analyses also recovered non-monophyly of taxa exhibiting multiple traits used as the basis for previous taxonomic hypotheses. Taxa with axe-head shaped glochidia were resolved as paraphyletic, but our results strongly suggest the complex morphology is an adaptation to reduce larval size, with reduction in size further accentuated in taxa previously assigned to Leptodea. To more accurately reflect the evolutionary history of this group, we make multiple systematic changes, including the description of a new genus, Atlanticoncha gen. nov., and the synonymy of the genus Leptodea under Potamilus. Our findings contribute to the growing body of literature showing that cladistic hypotheses based solely on morphological characters, including larval morphology, can be flawed in freshwater mussels.

Linking habitat structure to life history strategy: Insights from a Mediterranean killifish

The bean Phaseolus vulgaris is widely consumed by the Congolese population, because it is rich in protein and has a good nutritional quality. Beetles of the subfamily Bruchinae are pests of bean seeds in the field and storage in the Republic of Congo (RC). Their attacks cause a reduction in seed weight, leading to a decrease in the nutritional and commercial value of the seeds. The purpose of our study was to identify the post-harvest diversity of bean bruchids in two bean producing regions in the Congo (Niari and Bouenza) using molecular taxonomy (12S rRNA marker). The bean weevil, Acanthoscelides obtectus (Say), and cowpea weevil, Callosobruchus maculatus (Fabricius), were identified. Acanthoscelides obtectus, recognised as the main pest of beans, was found in all ten localities sampled, whereas C. maculatus, recognised as the main pest of pigeon peas (Cajanus cajan) and chickpeas (Cicer arietinum), was found in two of the ten. Better knowledge of the diversity of bruchids present in the RC will make it possible to propose effective control methods with little impact on environmental and human health.

The effectiveness of drug plant and of essential oil of oregano (Origanum vulgare L. ssp. hirtum Ietswaart) against the adults and egg hatching of bean weevil (Acanthoscelides obtectus Say) was studied in laboratory trials in order to screen for a new potential insecticide in the control of this granary pest of beans. The adult mortality as well as oviposition and hatching capabilities were evaluated after 6 days of treatment of beans cv. `Berggold' (55 g) in Petri dishes by powdered drug (0.33 g, 0.66 g, 1.0 g and 2.0 g) and by equivalent amounts of essential oil (5 ill, 10 15 ill and 30 ill). Oregano essential oil showed both fumigant and contact toxicities to bean weevil, the later being more potent. When considering fumigant toxicity, insecticidal effect (mortality rate 82.5%) was observed 6 days after application of high concentrations of oregano essential oil (150 Al per 55 g of beans). When considering contact toxicity, both oregano drug plant and essential oil at all tested concentrations significantly increased the bean weevils' mortality rates with comparison to the controls. Also, egg laying and hatching were inhibited after treatment of bean weevil with powdered drug plant or with essential oil at all tested concentrations. Insecticidal effect of drug plants issuing from two different stocks depended on their essential oil contents. Essential oils (5 pi, 15 pi and 30 IA per 55 g of beans) induced 100% mortality of bean weevil population when applied directly to the surface of beans (55 g) in Petri dishes. The content of essential oil in oregano and oregano-based preparations for insecticidal use is proposed as a parameter for quality control purposes.

The bean weevil (Acanthoscelides obtectus Say) is an aggressive post‐harvest pest of the common bean (Phaseolus vulgaris L.). Bean common mosaic virus (BCMV) and Bean common mosaic necrosis virus (BCMNV) are important seedborne diseases of dry bean in the Americas and Africa. The development of bean lines that combine resistance to BCMV, BCMNV, and bean weevils can help to reduce yield loss during the growing season and avoid seed damage during storage. AO‐1012‐29‐3‐3A, (Reg. No. GP‐299, PI 675563) is a multiple virus and bean weevil‐resistant bean germplasm line adapted to the humid tropics; it was developed and released cooperatively in 2015 by Sokoine University of Agriculture, Oregon State University, the USDA‐ARS, and the University of Puerto Rico. AO‐1012‐29‐3‐3A has a determinate growth habit and a dark red kidney seed type similar to the cultivar Rojo, which is commercially acceptable in Tanzania. AO‐1012‐29‐3‐3A possesses the I and bc‐12 genes that confer resistance to BCMV and BCMNV. AO‐1012‐29‐3‐3A produced a mean seed yield similar to the checks USLK‐1 and ‘Badillo’ in three trials planted in Puerto Rico. Seed of AO‐1012‐29‐3‐3A had greater levels of threonine, proline, analine, valine, lysine, methionine, and crude protein compared with the check cultivar Badillo. AO‐1012‐29‐3‐3A should serve as a useful source of resistance to the bean weevil, BCMV, and some pathogroups of BCMNV.

Life history traits in many ectotherms show complex patterns of variation among conspecific populations sampled along wide latitudinal or climatic gradients. However, few studies have assessed whether these patterns can be explained better by thermal reaction norms of multiple life history traits, covering major aspects of the life cycle. In this study, we compared five populations of a Holarctic, numerically dominant soil microarthropod species, Folsomia quadrioculata, sampled from a wide latitudinal gradient (56–81°N), for growth, development, fecundity, and survival across four temperatures (10, 15, 20, and 25°C) in common garden experiments. We evaluated the extent to which macroclimate could explain differences in thermal adaptation and life history strategies among populations. The common garden experiments revealed large genotypic differences among populations in all the traits, which were little explained by latitude and macroclimate. In addition, the life history strategies (traits combined) hardly revealed any systematic difference related to latitude and macroclimate. The overall performance of the northernmost population from the most stochastic microclimate and the southernmost population, which remains active throughout the year, was least sensitive to the temperature treatments. In contrast, performance of the population from the most predictable microclimate peaked within a narrow temperature range (around 15°C). Our findings revealed limited support for macroclimate‐based predictions, and indicated that local soil habitat conditions related to predictability and seasonality might have considerable influence on the evolution of life history strategies of F. quadrioculata. This study highlights the need to combine knowledge on microhabitat characteristics, and demography, with findings from common garden experiments, for identifying the key drivers of life history evolution across large spatial scales, and wide climate gradients. We believe that similar approaches may substantially improve the understanding of adaptation in many terrestrial ectotherms with low dispersal ability.

Bean weevil [Acanthoscelides obtectus Say (Coleoptera: Bruchidae)] is considered the main storage pest of the bean crop. Its control is performed mainly by chemical treatment, which has potential to cause resistance in pests, as well as environmental contamination. This study aimed at evaluating the insecticidal and repellent effect of Salvia officinalis L. essential oil against bean weevil. The doses used for the insecticidal test were: 0 L t-1, 0.5 L t-1, 1.0 L t-1, 1.5 L t-1, 2.5 L t-1 and 5.0 L t-1 of bean grains. For the mortality test, the experimental design was completely randomized, in a 6 × 7 (dose × time) factorial scheme, with five replications. The number of dead insects was counted at 2, 6, 12, 24, 48, 72 and 96 h after the insect introduction. The repellency test was conducted in arenas, under a completely randomized design, using the same doses applied to evaluate the insecticidal effect. Counts were performed 24 h after the introduction of insects. The insecticidal effect of the S. officinalis essential oil on A. obtectus resulted in mortality rates higher than 95 %, after 6 h of insect introduction, for all doses tested. Repellency effect was also detected for all doses tested.

The issue of storage and protection of yilded seeds from storage pests is fundamental to seed science, the nutrition of people and animals as well as the maintenance of state reserves. During 2019-2021, in the experimental field of IASS "Obraztsov chiflik" -Rousse, in a long-term stationary fertilizer experiment, seeds of common bean variety Obraztsov chiflik 12 were obtained utilizing the following fertilization options: 1 -individual nitrogen fertilization; 2individual phosphorus fertilization; 3 -individual potassium fertilization; 4 -combined NP application; 5 -combined NK application; 6 -combined PK application; 7 -triple combination of NPK. An unfertilized control variant was maintained for comparison purposes. The study aims to entomologically evaluate seeds regarding damage by bean weevils after crop harvesting. Measurements of yield, 1000-seed weight, damaged seeds percentage, Index of infestation, as well as weight loss were taken. The combined application of NP demonstrated the greatest positive effect on the yield qualities of beans, however it lead to an intermediate position of the yield in terms of damage by bean weevil. The variant treated with combined NK fertilization resulted in the lowest percentage of damaged seeds and Index of infestation; it was followed by the variant with full mineral fertilization and the control variant. The individual application of N resulted in highest damaged seeds percentage as well as highest Index of infestation; it also ensured the highest weight loss on average for the studied period.

In common bean (Phaseolus vulgaris L.), the most abundant seed proteins are the storage protein phaseolin and the family of closely related APA proteins (arcelin, phytohemagglutinin and α-amylase inhibitor). High variation in APA protein composition has been described and the presence of arcelin (Arc) has been associated with bean resistance against two bruchid beetles, the bean weevil (Acanthoscelides obtectus Say) and the Mexican bean weevil (Zabrotes subfasciatus Bohemian). So far, seven Arc variants have been identified, all in wild accessions, however, only those containing Arc-4 were reported to be resistant to both species. Although many efforts have been made, a successful breeding of this genetic trait into cultivated genotypes has not yet been achieved. Here, we describe a newly collected wild accession (named QUES) and demonstrate its resistance to both A. obtectus and Z. subfasciatus. Immunological and proteomic analyses of QUES seed protein composition indicated the presence of new Arc and arcelin-like (ARL) polypeptides of about 30 and 27kDa, respectively. Sequencing of cDNAs coding for QUES APA proteins confirmed that this accession contains new APA variants, here referred to as Arc-8 and ARL-8. Moreover, bioinformatic analysis showed the two proteins are closely related to APA components present in the G12949 wild bean accession, which contains the Arc-4 variant. The presence of these new APA components, combined with the observations that they are poorly digested and remain very abundant in A. obtectus feces, so-called frass, suggest that the QUES APA locus is involved in the bruchid resistance. Moreover, molecular analysis indicated a lower complexity of the locus compared to that of G12949, suggesting that QUES should be considered a valuable source of resistance for further breeding purposes.