Founding weaver ant queens (Oecophylla longinoda) increase production and nanitic worker size when adopting nonnestmate pupae

Weaver ants (Oecophylla longinoda Latreille) are used commercially to control pest insects and for protein production. In this respect fast colony growth is desirable for managed colonies. Transplantation of non-nestmate pupae to incipient colonies has been shown to boost colony growth. Our objectives were to find the maximum number of pupae a founding queen can handle, and to measure the associated colony growth. Secondly, we tested if transplantation of pupae led to production of larger nanitic workers (defined as unusually small worker ants produced by founding queens in their first batch of offspring). Forty-five fertilized queens were divided into three treatments: 0 (control), 100 or 300 non-nestmate pupae transplanted to each colony. Pupae transplantation resulted in highly increased growth rates, as pupae were readily adopted by the queens and showed high proportions of surviving (mean = 76%). However, survival was significantly higher when 100 pupae were transplanted compared to transplantation of 300 pupae, indicating that queens were unable to handle 300 pupae adequately and that pupae require some amount of nursing. Nevertheless, within the 60-day experiment the transplantation of 300 pupae increased total colony size more than 10- fold whereas 100 pupae increased the size 5.6 fold, compared to control. This increase was due not only to the individuals added in the form of pupae but also to an increased per capita brood production by the resident queen, triggered by the adopted pupae. The size of hatching pupae produced by the resident queen also increased with the number of pupae transplanted, leading to larger nanitic workers in colonies adopting pupae. In conclusion, pupae transplantation may be used to produce larger colonies with larger worker ants and may thus reduce the time to produce weaver ant colonies for commercial purposes. This in turn may facilitate the implementation of the use of weaver ants.Weaver ants (Oecophylla longinoda Latreille) are used commercially to control pest insects and for protein production. In this respect fast colony growth is desirable for managed colonies. Transplantation of non-nestmate pupae to incipient colonies has been shown to boost colony growth. Our objectives were to find the maximum number of pupae a founding queen can handle, and to measure the associated colony growth. Secondly, we tested if transplantation of pupae led to production of larger nanitic workers (defined as unusually small worker ants produced by founding queens in their first batch of offspring). Forty-five fertilized queens were divided into three treatments: 0 (control), 100 or 300 non-nestmate pupae transplanted to each colony. Pupae transplantation resulted in highly increased growth rates, as pupae were readily adopted by the queens and showed high proportions of surviving (mean = 76%). However, survival was significantly higher when 100 pupae were transplanted compared to transplantation of 300 pupae, indicating that queens were unable to handle 300 pupae adequately and that pupae require some amount of nursing. Nevertheless, within the 60-day experiment the transplantation of 300 pupae increased total colony size more than 10- fold whereas 100 pupae increased the size 5.6 fold, compared to control. This increase was due not only to the individuals added in the form of pupae but also to an increased per capita brood production by the resident queen, triggered by the adopted pupae. The size of hatching pupae produced by the resident queen also increased with the number of pupae transplanted, leading to larger nanitic workers in colonies adopting pupae. In conclusion, pupae transplantation may be used to produce larger colonies with larger worker ants and may thus reduce the time to produce weaver ant colonies for commercial purposes. This in turn may facilitate the implementation of the use of weaver ants.Weaver ants (Oecophylla longinoda Latreille) are used commercially to control pest insects and for protein production. In this respect fast colony growth is desirable for managed colonies. Transplantation of non-nestmate pupae to incipient colonies has been shown to boost colony growth. Our objectives were to find the maximum number of pupae a founding queen can handle, and to measure the associated colony growth. Secondly, we tested if transplantation of pupae led to production of larger nanitic workers (defined as unusually small worker ants produced by founding queens in their first batch of offspring). Forty-five fertilized queens were divided into three treatments: 0 (control), 100 or 300 non-nestmate pupae transplanted to each colony. Pupae transplantation resulted in highly increased growth rates, as pupae were readily adopted by the queens and showed high proportions of surviving (mean = 76%). However, survival was significantly higher when 100 pupae were transplanted compared to transplantation of 300 pupae, indicating that queens were unable to handle 300 pupae adequately and that pupae require some amount of nursing. Nevertheless, within the 60-day experiment the transplantation of 300 pupae increased total colony size more than 10- fold whereas 100 pupae increased the size 5.6 fold, compared to control. This increase was due not only to the individuals added in the form of pupae but also to an increased per capita brood production by the resident queen, triggered by the adopted pupae. The size of hatching pupae produced by the resident queen also increased with the number of pupae transplanted, leading to larger nanitic workers in colonies adopting pupae. In conclusion, pupae transplantation may be used to produce larger colonies with larger worker ants and may thus reduce the time to produce weaver ant colonies for commercial purposes. This in turn may facilitate the implementation of the use of weaver ants.Weaver ants (Oecophylla longinoda Latreille) are used commercially to control pest insects and for protein production. In this respect fast colony growth is desirable for managed colonies. Transplantation of non-nestmate pupae to incipient colonies has been shown to boost colony growth. Our objectives were to find the maximum number of pupae a founding queen can handle, and to measure the associated colony growth. Secondly, we tested if transplantation of pupae led to production of larger nanitic workers (defined as unusually small worker ants produced by founding queens in their first batch of offspring). Forty-five fertilized queens were divided into three treatments: 0 (control), 100 or 300 non-nestmate pupae transplanted to each colony. Pupae transplantation resulted in highly increased growth rates, as pupae were readily adopted by the queens and showed high proportions of surviving (mean = 76%). However, survival was significantly higher when 100 pupae were transplanted compared to transplantation of 300 pupae, indicating that queens were unable to handle 300 pupae adequately and that pupae require some amount of nursing. Nevertheless, within the 60-day experiment the transplantation of 300 pupae increased total colony size more than 10- fold whereas 100 pupae increased the size 5.6 fold, compared to control. This increase was due not only to the individuals added in the form of pupae but also to an increased per capita brood production by the resident queen, triggered by the adopted pupae. The size of hatching pupae produced by the resident queen also increased with the number of pupae transplanted, leading to larger nanitic workers in colonies adopting pupae. In conclusion, pupae transplantation may be used to produce larger colonies with larger worker ants and may thus reduce the time to produce weaver ant colonies for commercial purposes. This in turn may facilitate the implementation of the use of weaver ants

Pupae transplantation to boost early colony growth in the weaver ant Oecophylla longinoda Latreille (Hymenoptera: Formicidae)

Oecophylla ants are currently used for biological control in fruit plantations in Australia, Asia and Africa and for protein production in Asia. To further improve the technology and implement it on a large scale, effective and fast production of live colonies is de¬sirable. Early colony development may be artificially boosted via the use of multiple queens (pleometrosis) and/or by adoption of foreign pupae in developing colonies. In the present experiments, we tested if multiple queens and transplantation of pupae could boost growth in young Oecophylla longinoda colonies. We found out that colonies with two queens artificially placed in the same nest, all perished due to queen fighting, suggesting that pleometrosis is not used by O. longinoda in Benin. In contrast, pupae transplantation resulted in highly increased growth rates, as pupae were readily adopted by the queens and showed high survival rates (mean = 92%). Within the 50-day experi¬ment the total number of individuals in colonies with 50 and 100 pupae transplanted, increased with 169 and 387%, respectively, compared to colonies receiving no pupae. This increase was both due to the individuals added in the form of pupae but also due to an increased per capita brood production by the resident queen, triggered by the adopted pupae. Thus pupae transplantation may be used to shorten the time it takes to produce weaver ant colonies in ant nurseries, and may in this way facilitate the imple-mentation of weaver ant biocontrol in West Africa

Caractéristiques physico-chimiques, phytochimiques et toxicité des espèces végétales utilisées comme emballages alimentaires en Afrique de l’Ouest

Le présent travail vise à caractériser quatre espèces de feuilles végétales utilisées comme emballages alimentaires en Afrique de l’Ouest. La caractérisation a été réalisée au plan physico-chimique, phytochimique et de la toxicité au moyen de méthodes de références. Il est apparu que les teneurs en protéines, en lipides totaux et en cendres totales sont respectivement de 6,0 ; 4,6 ; 8,7% pour Tectona grandis ; 16,0 ; 4,3 ;  9,1% pour Musa sapientum ; 12,5 ; 4,6 ; 7,0% pour Thalia geniculata et 13,4 ; 2,0 ; 7,2% pour Manihot esculenta. Une diminution significative de ces valeurs a été observée après 3 jours de conservation des produits emballés dans ces espèces de feuilles. Le fer est présent dans toutes les espèces, notamment dans Manihot esculenta (8,4%), Tectona grandis (4,4%) avec une légère diminution après emballage des produits. La teneur en vitamine C est présente uniquement dans les feuilles de  Manihot esculenta dans l’ordre de 0,4%. Les tanins, les catéchiques, les anthocyanes, les leuco-anthocyanes, les mucilages, les flavonoïdes et les coumarines ont été identifiés dans toutes les espèces de feuilles  analysées. Toutes les espèces de feuilles analysées se sont révélées non toxiques.Mots clés : Emballages végétaux, emballages alimentaires, Bénin, valeur nutritionnelle, toxicité des plantes, caractéristiques phytochimiques

Effects of farmers' practices of fertilizer application and land use types on subsequent maize yield and nutrient uptake in central Benin

Four on-farm experiments in central Benin examined whether land-use succession and fertilizer treatments for prior cotton would sustain subsequent maize crop yields and achieve balanced plant nutrition. Treatments consisted of three prior land use successions, i.e. before planting maize (egusi melon-cotton-cotton-maize, cotton-maize-cotton-maize and cassava-maize-cotton-maize) including for each, four replications of three fertilizer treatments: recommended practice [150 kg ha -1 of 14-23-14 (NPK) plus 5S-1B, applied 25 days after sowing and 50 kg ha -1 of urea on 40 days after sowing], NPK-SB mixed with urea (the recommended amount of NPK-SB and urea are mixed then applied 40 days after sowing) and reduced NPK-SB dose (recommended practice, but the amount of NPK-SB is reduced to 100 kg ha -1). Prior cotton and subsequent maize yields and nutrient uptake were not significantly affected by fertilizer treatments. Furthermore, fertilizer treatments had no significant effect on soil chemical properties before planting the subsequent maize crop. Land use types had significant effect on cotton yields, soil chemical properties, subsequent maize yields and nutrient uptake. The lowest yield and nutrient uptake were registered in the cotton-maize-cotton-maize land use succession and the highest in the egusi melon-cotton-cotton-maize succession. For sustainable soil fertility management, adoption of adequate crop succession system and recommended fertilizer application practice are suggested

Effectiveness of neem seed oil (Azadirachta indica A. Juss: Meliaceae) on Syllepte derogata Fabricius, Lepidoptera: Pyralidae

Objective: Synthetic insecticides have long been used for cotton protection,  resulting in pest resistance, toxicity and environmental pollution. Biopesticides have been suggested as alternatives to synthetic pesticides. Both field and laboratory experiments were conducted to evaluate the effectiveness of neem oil in controlling Syllepte derogata (Fabricius), a cotton phyllophagous pest.Methodology and Results: In the field trials, effect of neem oil was compared to that of conventional insecticides; while in the laboratory direct larval immersion and leaf dip method using EMA SUPER 56DC and neem oil were tested. Decrease in damage by S. derogata for about 63 and 86% was recorded with neem oil and synthetic insecticides. In the laboratory, the mortality of S. derogata after 24 hours exposure to neem oil and Ema Super was significantly higher (2.5 to 100%) than that of the control. The mortality of larvae of S. derogata was positively correlated with the concentration of neem oil and exposure time. Lethal Concentration (LC50) after 24 hours exposure of larvae was respectively 4.03 104 ml/l and 51.13 ml/l forleaf dipping method and larval immersion.Conclusion and application of results: Overall, these results showed the efficacy of neem oil in controlling S. derogata, as a biopesticide. This oil could also  constitute a successful alternative to synthetic pesticides. However, the  effectiveness of neem oil appeared to be weakened by the rapid degradation of the active substances, azadirachtin in particular. Indeed, azadirachtin, the main active ingredient of neem is photo and heat labile. It easily degrades under high solar radiations and high temperatures, hence the need for stabilization.Keywords: Phyllophagous pest, integrated pest management, leaf-dipping method, larval immersion, Lethal Concentration

Does the spillage of petroleum products in Anopheles breeding sites have an impact on the pyrethroid resistance?

<p>Abstract</p> <p>Background</p> <p>The emergence of <it>Anopheles </it>populations capable of withstanding lethal doses of insecticides has weakened the efficacy of most insecticide based strategies of vector control and, has highlighted the need for further studies on the mechanisms of insecticide resistance and the various factors selecting resistant populations of mosquitoes. This research targeted the analysis of breeding sites and the oviposition behaviour of susceptible and resistant populations of <it>Anopheles </it>in localities of spilled petroleum products. The aim was to establish the possible contribution of oil spillage in the selection of pyrethroid resistance in malaria vectors.</p> <p>Methods</p> <p><it>Anopheles </it>breeding sites were identified and the insecticide susceptibility of the <it>Anopheles gambiae </it>populations mapped in 15 localities of South Western Nigeria. The presence of oil particles as well as the turbidity, the dissolved oxygen and the pH of each identified breeding site was recorded. Data were cross-analysed to correlate the habitat types and the insecticide susceptibility status of emerging mosquitoes. The second phase of this study was basically a laboratory model to provide more information on the implication of the spillage of petroleum on the selection of pyrethroid resistance in <it>An. gambiae</it>.</p> <p>Results</p> <p>Moderate levels of resistance following exposure to permethrin-impregnated papers were recorded with the majority of <it>An. gambiae </it>samples collected in the South Western Nigeria. Data from this study established a link between the constituency of the breeding sites and the resistance status of the emerging <it>Anopheles</it>.</p> <p>Conclusion</p> <p>This study has revealed the segregational occupation of breeding habitats by pyrethroid resistant and susceptible strains of <it>An. gambiae </it>in south-western Nigeria. Compiled results from field and laboratory research point out clear relationships between oil spillage and pyrethroid resistance in malaria vectors. The identification of this factor of resistance could serve as strong information in the management of insecticide resistance in some West African settings.</p

Insectes nuisibles du mais entrepose; biologie et methodes du lutte: Guide de recherche de lIita, No. 32

En Afrique, Ie mals entrepose subit souvent des dgRts et des pertes considerables. II importe des lors d'identifier les insectes des produits entreposes d'une region don nee alin de determiner leur impor-tance et de choisir, Ie cas echeant, les methodes de lutte appropriees. La comprehension des facteurs determi-nant !'infestation avant et apres la recolte, ainsi que la connaissance de la biologie des ravageurs sont indis-pensables pour maitriser les insectes du maiS entre-pose

État et perspectives de lutte contre Sitotroga cerealella (Olivier, 1789), déprédateur des céréales au Bénin : synthèse bibliographique.

Objectif : Le présent article de revue fait état des études relatives aux différentes méthodes de lutte contre Sitotroga cerealella (alucite des céréales) et met l’accent sur l’utilisation des substances naturelles en perspective de lutte contre ce déprédateur. S. cerealella est l’un des ravageurs les plus redoutables dans les systèmes de conservation traditionnels en Afrique et particulièrement au Bénin. Méthodologie et Résultats : Dans la recherche des informations sur les luttes contre l’alucite des céréales, plusieurs travaux scientifiques publiés ont été consultés et leur synthèse a été faite. L’examen des résultats de recherche sur le contrôle de ce déprédateur de plusieurs céréales a révélé l’utilisation fréquente de produits chimiques de synthèse comme la deltaméthrine, le malathion et la phosphine seuls ou combinés en fumigation surtout. Plusieurs chercheurs se sont intéressés, dans le cadre des luttes physiques, aux irradiations ionisantes provenant de source de rayons gamma du cobalt 60 et des variétés de céréales résistantes dans le cas du riz, du blé ou de maïs. Aussi, des parasites, pathogènes ou prédateurs (Trichogramma spp, Blattisocius tarsalis, Cotesia ruficrus, Pteromalus cerealella et Bracon hebetor) ont-ils été expérimentés comme insecticide biologique sur différents stades de développement de S. cerealella. Les traitements à base de poudres ou d’extraits de plantes à potentialités insecticides ou insectifuges tels que ceux de Cymbopogon citratus, Tagetus erecta, Chenopodium ambrosioides, Azadirachta indica, Zanthoxylum zanthoxyloides et de Khaya ivorensisaux ont été étudiés. Cependant, contrairement à d’autres ravageurs comme Sitophilus spp, Rhizopertha dominica, Prostephanus truncatus, Tribolium sp ou même Callosobruchus sp, peu de travaux sont réalisés sur la lutte contre l’alucite des céréales au moyen d’extraits volatiles de plantes. Conclusion : Les huiles essentielles des plantes aromatiques du Bénin pourraient être efficaces dans le contrôle des populations de S. cerealella dans la conservation des stocks de riz.Mots-clés : Lutte biologique, Sitotroga cerealella, céréales, riz, substances naturelles.Status and perspectives of struggle against Sitotroga cerealella (Olivier, 1789), pest of cereals in Benin: a short reviewObjective: This review article describes the studies on different methods of fighting against Sitotroga cerealella (Angoumois Grain Moth), and the focus was on the use of non-chemical methods to display a biological fight. S. cerealella is one of the most dangerous pests in traditional systems of conservation in Africa and particularly in Benin. Methods and Results: In the search for information about the struggles against the Angoumois grain moth , several published scientific works were consulted . Examination of the results of research on the control of this pest infesting several cereals revealed frequent use of synthetic chemicals such as deltamethrin, malathion and phosphine fumigation alone or in combination. Several researchers were interested in the physical struggles, ionizing radiation from gamma source of cobalt-60 and resistant varieties of grain in the case of rice, wheat or corn. Also, parasites, pathogens and predators (Trichogramma spp, Blattisocius tarsalis, Cotesia ruficrus, Pteromalus cerealella and Bracon hebetor) were experienced as biological insecticide on different developmental stages of S. cerealella. Treatments based on powders, extracts or cooking oils of plants such insecticides like Cymbopogon citratus, Tagetus erecta, Chenopodium ambrosioides, Azadirachta indica, Zanthoxylum zanthoxyloides and Khaya ivorensisaux were studied. However, unlike other pest insects like Sitophilus spp, Rhyzopertha dominica, Prostephanus truncatus, Tribolium sp or even Callosobruchus sp, little work is done in the field of fight against Angoumois grain moth.through volatile extracts. Conclusion : Essential oils from aromatic plants of Benin could effectively control populations of S. cerealella in the conservation of stocks of rice.Keywords: control, Sitotroga cerealella, Cereal, rice, natural substances

Growth dynamics of tree nursery seedlings: The case of oil palm

Tree seedling survival in the field partly depends on management during seedling production. Insight into how nursery practices affect seedling growth dynamics would generate understanding in how to optimise tree seedling production. The objective of this study was to analyse the growth dynamics of oil palm seedlings to evaluate the effects of bag size, substrate type, and fertiliser supply, and their interactions. An experiment was run in 2011 (March to November 2011) and repeated in 2012 (April to October 2012) using three bag sizes, four substrates, and three levels of fertiliser supply (3 × 4 × 3 factorial design). Seedling height, collar diameter and number of leaves were measured over time. Seedling growth was analysed by comparing treatment effects at monthly intervals. Data were also fitted to growth curves to analyse treatment effects on absolute and relative rates of increase in seedling height, collar diameter and number of leaves. While substrate and fertiliser supply effects were fairly constant over time, bag size effects increased with larger variance explained over time. We observed that bag size effects overtook substrate, fertiliser and interaction effects from about two months onwards. Seedling height and collar diameter followed an exponential growth while number of leaves increased linearly over time. Analysis of generated data with the different growth models indicated that seedling growth rates were mainly under the influence of bag size, followed by substrate. Interactions between nursery practices, although significant sometimes, did not account for a large part of experimental error. Implications for tree seedling management are further discussed

Effet de la nature de la jachère sur la colonisation de la culture subséquente par les champignons endomycorhiziens : cas du système ‘jachère’ manioc sur sols ferrugineux tropicaux du Bénin

En vue d’évaluer les arrières effets d’une fumure d’engrais minéral sur la croissance du maïs et la capacité des champignons endomycorhiziens à mobiliser le phosphore, quatre cultures successives de maïs ont été conduites en pots sous serre sur des échantillons de sol collectés au niveau de trois types de ‘jachère’ manioc ayant comporté les variétés de manioc Ben 86052, Bouaké (variété traditionnelle introduite), et odongbo (variété locale utilisée comme référence). Deux doses d’engrais complexe N14P23K14 (0 et 100 kg/ha correspondant à 14 kg de N; 10,12 kg de P et 11,62 kg de K) ont été appliquées à la première culture de maïs en champ en 2004. On note une baisse significative (