Impact of fertility versus mortality control on the demographics of Mastomys natalensis in maize fields

The multimammate mouse,Mastomys natalensis,is the most common rodent pest species in sub-Saharan Africa.Currently,rodenticides are the preferred method used to reduce the population of rodent pests,but this method poses direct and indirect risks to humans and other non-target species.Fertility control is a promising alternative that has been argued to be a more sustainable and humane method for controlling rodent pests.In this study,we compared the effectiveness of fertility control bait EP-1(quinestrol(E)and levonorgestrel(P),10 ppm)and an anticoagulant rodenticide bait(bromadiolone,50 ppm)on the population dynamics of M.natalensis in maizefields in Zambia during 2 cropping seasons.M.natalensis was the most abundant species in maizefields(77%of total captures).Fertility control reduced the number of juveniles and suppressed population growth of M.natalensis at the end of the 2019–2020 cropping season.The population density initially decreased after rodenticide treatment,but the population rapidly recovered through immigration.None of the treatments influenced maize damage by rodents at germination(F2,67=1.626,P=0.204).Applying the treatments during the maize seeding time was effective at suppressing population growth at the end of the cropping season than application the month before maize seeding.This research indicates that a single-dose delivery of EP-1 and rodenticide have comparable effects on the population dynamics of M.natalensis.Thesefindings are important in developing fertility control protocols for rodent pest populations to reduce maize crop damage and improve yields.

Recent advances in the utilization of insects as an ingredient in aquafeeds:A review

The aquafeed industry continues to expand in response to the rapidly growing aquaculture sector.However,the identification of alternative protein sources in aquatic animal diets to replace conventional sources due to cost and sustainability issues remains a major challenge.Recently,insects have shown tremendous results as potential replacers of fishmeal in aquafeed.The present study aimed to review the utilization of insects in aquafeeds and their effects on aquatic animals’growth and feed utilization,immune response and disease resistance,and fish flesh quality and safety.While many insect species have been investigated in aquaculture,the black soldier fly(Hermetia illucens),and the mealworm(Tenebrio molitor)are the most studied and most promising insects to replace fishmeal in aquafeed.Generally,insect rearing conditions and biomass processing methods may affect the product’s nutritional composition,digestibility,shelf life and required insect inclusion level by aquatic animals.Also,insect-recommended inclusion levels for aquatic animals vary depending on the insect species used,biomass processing method,and test organism.Overall,while an appropriate inclusion level of insects in aquafeed provides several nutritional and health benefits to aquatic animals,more studies are needed to establish optimum requirements levels for different aquaculture species at different stages of development and under different culture systems.