Sesbania species (Fabaceae) are a valuable plant resource in tropical agriculture. Recently, Mesoplatys ochroptera Stål (Coleoptera : Chrysomelidae) has become a serious pest of Sesbania species in agroforestry systems in Africa. The biology of M. ochroptera was studied in eastern Zambia and southern Malawi. Sesbania bispinosa (Jacq.) Wight, S. brevipedunculata Gillet, S. leptocarpa DC, S. macrantha Phil. & Hutch., S. rostrata Bremek & Obrem, S. sericea (Willd.) Link, S. sesban (L.) Merr. and S. tetraptera Hochst. ex Baker were the primary hosts of M. ochroptera in the study area. Females laid on average one egg batch per day in an oviposition period of 18-56 days. Egg batches contained 2-70 eggs. Females that were mated repeatedly produced about 1000 offspring while those mated only once produced 980 offspring. Larval development through three instars, took between 11-34 days. Pupal development occurred in the soil, and took 4-16 days. The survival and developmental periods of pre-imaginal stages differed significantly between the Sesbania species studied. The highest and lowest pre-imaginal survival was recorded on S. leptocarpa and S. rostrata, respectively. The longest developmental period of about 32 days was recorded on S. sesban while the shortest of 14 days was on S. leptocarpa. Annual activity cycle in M. ochroptera followed the unimodal rainfall pattern of southern central Africa. Beetles were only active during the rainy season (November-April) with a single population peak between February and April. Adults overwintered within and around the sesbania fallows during the long dry season (May-October) and emerged with the onset of the rains.
Tag: beetles
Performance of sesbania sesban infested by the defoliating beetle mesoplatys ochroptera in Zambia
Developing integrated pest management practices against the defoliating beetle Mesoplatys ochroptera is an important aspect of the adoption of Sesbania sesban as an improved fallow species in southern Africa. The effect of defoliation by M.ochroptera on the growth of S. sesban(provenance Kakamega) was studied during 1998–2000 at Msekera Research Station in eastern Zambia. To determine the relationship between M. ochroptera densities and degree of defoliation, potted seedlings were infested manually with different densities of larvae and adults. Infestation of two to three month old seedlings with 5–30 larvae or adults resulted in less than 20% defoliation. Infestation of seedlings with 90–150 larvae(>3 masses of eggs) led to 80–100% and 50–80% defoliation in two and three months old seedlings, respectively. The time of infestation and degree of defoliation that lead to reduction in growth and biomass were determined using simulated (manual) defoliation of one to three months old S. sesban seedlings. Manual removal of 50–100% of the foliage atone and two months after transplanting (MAP) appeared to reduce plant height, basal diameter, primary branches, leaf and wood biomass compared to that done atthree MAP. Removal of 25–50% of the sesbania foliage three months after transplanting apparently leads to overcompensation. In sesbania, compensatory growth occurred when 25–50% of the leaves were defoliated three months after transplanting. Therefore, farmers need to protect sesbania seedlings from defoliation against insects such as M. ochroptera only during the first two months after transplanting.
Fungi and insects as models of extraordinary symbiosis
Symbiosis among microorganisms represents an interesting relationship that takes different shapes. Obligatory, facultative, and endosymbiotic relationships have all been reported between different microorganisms. Whether it is mutualism, commensalism, amensalism, or parasitism, understanding every association is of great importance to science and humanity. Knowing how these creatures benefit from each other may be useful for biocontrol purposes, or even for discovery of novel metabolites that result from these associations, and which may not be produced by the individual species. In this review, five examples of symbiosis were presented, including among the Laboulbeniales; Septobasidium; Ambrosia Fungi and Beetles; Leaf-cutter ants and their fungus gardens; and finally, termites and Termitomyces. Moreover, the benefits each partner is getting were highlighted, and uniqueness in every form of those symbiosis models was simply described.