Integrating temperature-dependent life table data into Insect Life Cycle Model for predicting the potential distribution of <em>Scapsipedus icipe</em> Hugel &amp; Tanga

Scapsipedus icipe Hugel and Tanga (Orthoptera: Gryllidae) is a newly described edible cricket species. Although, there is substantial interest in mass production of S. icipe for human food and animal feed, no information exists on the impact of temperature on their bionomics. Temperature-dependent development, survival, reproductive and life table parameters of S. icipe was generated and integrated into advanced Insect Life Cycle Modeling software to describe relative S. icipe population increase and spatial spread based on nine constant temperature conditions. We examined model predictions and implications for S. icipe potential distribution in Africa under current and future climate. These regions where entomophagy is widely practiced have distinctly different climates. Our results showed that S. icipe eggs were unable to hatch at 10 and 40°C, while emerged nymphs failed to complete development at 15°C. The developmental time of S. icipe was observed to decrease with increased in temperature. The lowest developmental threshold temperatures estimated using linear regressions was 14.3, 12.67 and 19.12°C and the thermal constants for development were 185.2, 1111.1- and 40.7-degree days (DD) for egg, nymph and pre-adult stages, respectively. The highest total fecundity (3416 individuals/female/generation), intrinsic rate of natural increase (0.075 days), net reproductive rate (1330.8 female/female/generation) and shortest doubling time (9.2 days) was recorded at 30°C. The regions predicted to be suitable by the model suggest that S. icipe is tolerant to a wider range of climatic conditions. Our findings provide for the first-time important information on the impact of temperature on the biology, establishment and spread of S. icipe across the Africa continent. The prospect of edible S. icipe production to become a new sector in food and feed industry is discussed

Postharvest processes of edible insects in Africa: A review of processing methods, and the implications for nutrition, safety and new products development

In many African cultures, insects are part of the diet of humans and domesticated animals. Compared to conventional food and feed sources, insects have been associated with a low ecological foot print because fewer natural resources are required for their production. To this end, the Food and Agriculture Organization of the United Nations recognized the role that edible insects can play in improving global food and nutrition security; processing technologies, as well as packaging and storage techniques that improve shelf-life were identified as being crucial. However, knowledge of these aspects in light of nutritional value, safety, and functionality is fragmentary and needs to be consolidated. This review attempts to contribute to this effort by evaluating the available evidence on postharvest processes for edible insects in Africa, with the aim of identifying areas that need research impetus. It further draws attention to potential postharvest technology options for overcoming hurdles associated with utilization of insects for food and feed. A greater research thrust is needed in processing and this can build on traditional knowledge. The focus should be to establish optimal techniques that improve presentation, quality and safety of products, and open possibilities to diversify use of edible insects for other benefits

Minerals content of extruded fish feeds containing cricket (Acheta domesticus) and black soldier fly larvae (Hermetia illucens) fractions

Animal food sources provide human beings with minerals considerably in adequate quantities. Fish is an indispensable reliable source of nutrients, as aquaculture is a sector that is fast growing and which provides 50% of the world’s fish production. However, fish production is hampered by the increasing costs of feeds due to the ever rising cost of fish meal, an integral component of fish feeds. Substituting fish meal with cheap, yet highly nutritious ingredients in fish feeds is therefore paramount. This study investigated the effects of substituting fish meal with adult cricket meal (ACM) and black soldier fly meal (BSFM) on minerals content of extruded fish feeds, where four levels of substitution (0, 25, 50 and 75%) were used. The effect of feed moisture content on minerals was also studied where 20 and 30% feed moisture levels were used. Leaching effects of the pellets were studied as well. The results showed a significant increase (P < 0.05) in the levels of phosphorus and potassium as the level of fish meal substitution increased from 0 to 75%. On the other hand, iron and sodium levels reduced significantly (P < 0.05) as the level of fish meal substitution increased. Magnesium content increased with increasing level of substitution with BSFM, but decreased with increasing level of substitution with ACM. Copper, zinc and manganese were not greatly influenced by levels of fish meal substitution. Diets that had zero substitution showed higher leaching effect for most minerals than diets that were substituted with 75% ACM or BSFM. This study found that both ACM and BSFM can be used to substitute fish meal in fish feeds and obtain adequate mineral profile and low leaching effect

Physico-chemical properties of extruded aquafeed pellets containing black soldier fly (Hermetia illucens) larvae and adult cricket (Acheta domesticus) meals

Fish farming is faced with the challenge of high cost of feeds because of the cost of high quality protein needed for formulation of the feeds. Thus, there is urgent need for alternative protein sources. The effects of substituting freshwater shrimp meal (FWSM) with black soldier fly larvae meal (BSFM) or adult cricket meal (ACM) on physico-chemical properties of hot-extruded fish feed pellets were investigated. The FWSM protein in a 26 g/100 g protein fish feed formulation was substituted at 0, 25, 50 and 75%, and moisture content of the formulated blends adjusted to 10, 20 or 30 g/100 g prior to extrusion. Floatability, expansion rate, bulk density, durability index, water absorption index, water solubility index, and water stability of extruded pellets were determined. Sinking velocity and the total suspended and dissolved solids in water were determined for the optimal pellets. Pellet floatability was not influenced by the type of insect meal but the interaction between level of inclusion and moisture content of the feed at extrusion. Pellets with high floatability >90% were produced from all feed blends at 30 g/100 g moisture content. Expansion ratio, was not influenced by type of insect meal or the level of inclusion but by the moisture content whereby feed blends extruded at 30 g/100 g moisture gave pellets with high expansion ratio ~60%. Bulk density was influenced by the interaction of the three factors. Pellet durability and water absorption indices were not influenced by the investigated factors or their interactions. Processed pellets were generally highly durable (99%) out of water, but the stability in water was significantly influenced by the interaction of type of insect meal level of inclusion and moisture content at extrusion. Water solubility increased with increasing extrusion moisture. Overall, it was possible to process good quality extruded pellets with 75% BSFM or 75% ACM at 30 g/100 g feed moisture

Global habitat suitability of Spodoptera frugiperda (JE Smith) (Lepidoptera, Noctuidae): key parasitoids considered for its biological control

Open Access Journal; Published online: 24 Mar 2021The present study is the first modeling effort at a global scale to predict habitat suitability of fall armyworm (FAW), Spodoptera frugiperda and its key parasitoids, namely Chelonus insularis, Cotesia marginiventris,Eiphosoma laphygmae,Telenomus remus and Trichogramma pretiosum, to be considered for biological control. An adjusted procedure of a machine-learning algorithm, the maximum entropy (Maxent), was applied for the modeling experiments. Model predictions showed particularly high establishment potential of the five hymenopteran parasitoids in areas that are heavily affected by FAW (like the coastal belt of West Africa from Côte d’Ivoire (Ivory Coast) to Nigeria, the Congo basin to Eastern Africa, Eastern, Southern and Southeastern Asia and some portions of Eastern Australia) and those of potential invasion risks (western & southern Europe). These habitats can be priority sites for scaling FAW biocontrol efforts. In the context of global warming and the event of accidental FAW introduction, warmer parts of Europe are at high risk. The effect of winter on the survival and life cycle of the pest in Europe and other temperate regions of the world are discussed in this paper. Overall, the models provide pioneering information to guide decision making for biological-based medium and long-term management of FAW across the globe

Harnessing data science to improve integrated management of invasive pest species across Africa: an application to Fall armyworm (Spodoptera frugiperda) (J.E. Smith) (Lepidoptera: Noctuidae)

Open Access Journal; Published online: 11 Feb 2022After five years of its first report on the African continent, Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) is considered a major threat to maize, sorghum, and millet production in sub-Saharan Africa. Despite the rigorous work already conducted to reduce FAW prevalence, the dynamics and invasion mechanisms of FAW in Africa are still poorly understood. This study applied interdisciplinary tools, analytics, and algorithms on a FAW dataset with a spatial lens to provide insights and project the intensity of FAW infestation across Africa. The data collected between January 2018 and December 2020 in selected locations were matched with the monthly average data of the climatic and environmental variables. The multilevel analytics aimed to identify the key factors that influence the dynamics of spatial and temporal pest density and occurrence at a 2 km x 2 km grid resolution. The seasonal variations of the identified factors and dynamics were used to calibrate rule-based analytics employed to simulate the monthly densities and occurrence of the FAW for the years 2018, 2019, and 2020. Three FAW density level classes were inferred, i.e., low (0–10 FAW moth per trap), moderate (11–30 FAW moth per trap), and high (>30 FAW moth per trap). Results show that monthly density projections were sensitive to the type of FAW host vegetation and the seasonal variability of climatic factors. Moreover, the diversity in the climate patterns and cropping systems across the African sub-regions are considered the main drivers of FAW abundance and variation. An optimum overall accuracy of 53% was obtained across the three years and at a continental scale, however, a gradual increase in prediction accuracy was observed among the years, with 2020 predictions providing accuracies greater than 70%. Apart from the low amount of data in 2018 and 2019, the average level of accuracy obtained could also be explained by the non-inclusion of data related to certain key factors such as the influence of natural enemies (predators, parasitoids, and pathogens) into the analysis. Further detailed data on the occurrence and efficiency of FAW natural enemies in the region may help to complete the tri-trophic interactions between the host plants, pests, and beneficial organisms. Nevertheless, the tool developed in this study provides a framework for field monitoring of FAW in Africa that may be a basis for a future decision support system (DSS)

Co-founding ant queens prevent disease by performing prophylactic undertaking behaviour

Abstract Background Social insects form densely crowded societies in environments with high pathogen loads, but have evolved collective defences that mitigate the impact of disease. However, colony-founding queens lack this protection and suffer high rates of mortality. The impact of pathogens may be exacerbated in species where queens found colonies together, as healthy individuals may contract pathogens from infectious co-founders. Therefore, we tested whether ant queens avoid founding colonies with pathogen-exposed conspecifics and how they might limit disease transmission from infectious individuals. Results Using Lasius niger queens and a naturally infecting fungal pathogen Metarhizium brunneum, we observed that queens were equally likely to found colonies with another pathogen-exposed or sham-treated queen. However, when one queen died, the surviving individual performed biting, burial and removal of the corpse. These undertaking behaviours were performed prophylactically, i.e. targeted equally towards non-infected and infected corpses, as well as carried out before infected corpses became infectious. Biting and burial reduced the risk of the queens contracting and dying from disease from an infectious corpse of a dead co-foundress. Conclusions We show that co-founding ant queens express undertaking behaviours that, in mature colonies, are performed exclusively by workers. Such infection avoidance behaviours act before the queens can contract the disease and will therefore improve the overall chance of colony founding success in ant queens

Efficiency of food-based attractants for monitoring tephritid fruit flies diversity and abundance in mango systems across three west African agro-ecological zones

Published online: 18 Dec 2019Food baits are effective and widely used tools for monitoring diversity and abundance of tephritid fruit flies. Four food-baits—Nulure, BioLure, Mazoferm at 3 and 6%, and Torula yeast—were used in multi-lure traps over a 4-yr period in mango orchards in three Benin agro-ecological zones (AEZ) representing a large swath of environments in western Africa. Twelve tephritid fruit fly species were captured during the trials, with the highest richness in the Forest Savannah Mosaic (FSM), followed by the Southern Guinea Savannah (SGS), and the Northern Guinea Savannah (NGS) AEZ. Despite previous reports of displacement, the native species Ceratitis cosyra remained the dominant tephritid species in mango orchards in the NGS, with the invasive and exotic species Bactrocera dorsalis dominating the tephritid fauna in the SGS and FSM. Torula yeast captured the greatest number of fruit flies in each AEZ. Mazoferm-3% captures were similar to Torula yeast, except for lower captures in the NGS where it tended to harden. The rank order of relative efficiency indices (REI) of the food baits (relative to Torula yeast) is Mazoferm-3% > Nulure > Mazoferm-6% and BioLure. The latter captured more Ceratitis spp. than all the other baits, particularly at very low Ceratitis spp. abundance. To our knowledge, the study is the first to report relative efficiency indices for the selection of food baits in monitoring diversity and abundance of fruit flies. Ecological and practical implications for the use of food baits in comparison with male lures are discussed