Application of Remote Sensing Data for Locust Research and Management—A Review

Recently, locust outbreaks around the world have destroyed agricultural and natural vegetation and caused massive damage endangering food security. Unusual heavy rainfalls in habitats of the desert locust (Schistocerca gregaria) and lack of monitoring due to political conflicts or inaccessibility of those habitats lead to massive desert locust outbreaks and swarms migrating over the Arabian Peninsula, East Africa, India and Pakistan. At the same time, swarms of the Moroccan locust (Dociostaurus maroccanus) in some Central Asian countries and swarms of the Italian locust (Calliptamus italicus) in Russia and China destroyed crops despite developed and ongoing monitoring and control measurements. These recent events underline that the risk and damage caused by locust pests is as present as ever and affects 100 million of human lives despite technical progress in locust monitoring, prediction and control approaches. Remote sensing has become one of the most important data sources in locust management. Since the 1980s, remote sensing data and applications have accompanied many locust management activities and contributed to an improved and more effective control of locust outbreaks and plagues. Recently, open-access remote sensing data archives as well as progress in cloud computing provide unprecedented opportunity for remote sensing-based locust management and research. Additionally, unmanned aerial vehicle (UAV) systems bring up new prospects for a more effective and faster locust control. Nevertheless, the full capacity of available remote sensing applications and possibilities have not been exploited yet. This review paper provides a comprehensive and quantitative overview of international research articles focusing on remote sensing application for locust management and research. We reviewed 110 articles published over the last four decades, and categorized them into different aspects and main research topics to summarize achievements and gaps for further research and application development. The results reveal a strong focus on three species—the desert locust, the migratory locust (Locusta migratoria), and the Australian plague locust (Chortoicetes terminifera)—and corresponding regions of interest. There is still a lack of international studies for other pest species such as the Italian locust, the Moroccan locust, the Central American locust (Schistocerca piceifrons), the South American locust (Schistocerca cancellata), the brown locust (Locustana pardalina) and the red locust (Nomadacris septemfasciata). In terms of applied sensors, most studies utilized Advanced Very-High-Resolution Radiometer (AVHRR), Satellite Pour l’Observation de la Terre VEGETATION (SPOT-VGT), Moderate-Resolution Imaging Spectroradiometer (MODIS) as well as Landsat data focusing mainly on vegetation monitoring or land cover mapping. Application of geomorphological metrics as well as radar-based soil moisture data is comparably rare despite previous acknowledgement of their importance for locust outbreaks. Despite great advance and usage of available remote sensing resources, we identify several gaps and potential for future research to further improve the understanding and capacities of the use of remote sensing in supporting locust outbreak- research and management.

Comparing the Nutritional Composition of Some Edible Insects and Some Animal Meats in North-western State of Nigeria

Five different edible insects from Kaduna, Kebbi, Niger, Sokoto and Zamfara States of North-Western Nigeria, namely; Red Locust (Nomadacris setemfasciata), Desert Locust (Schistocerca gregaria), Variegated Grasshopper (Zonocerus wariegatus), Termite (Macrotermes bellicosus) and Brown Cricket (Gryllotapha Africana), were collected alongside with meats from camel (Camellus dromedaries), Cow (Bos indicus), Ram (Ovis aries), Chicken (Gallus gallus), and Fish (Clariaslazera). The insects were oven dried separately at 60ºC for 3-5hrs while the meats were dried at 60ºC for 48hrs. The dried contents of both the insects and the meats were ground separately and each was subjected to proximate analysis. The results indicated the nutrient to have Carbohydrates ranging between 0.7 g - 12.1 g in the insects and 0.4 g-10.2 g in the meats, Proteins ranging from 12.6 g - 57.3 g in the insects and 18.1 g – 70.4 g in the meats, Fats, Fibre, Ash and Moisture having ranges between 5 g - 17.9 g, 5 g - 20 g, 4g -10 g, 11.5 g - 53.6 g, respectively in insects and 18.4 g - 70.4 g Fats, 5 g Fibre, 2.4 g - 10.4 g Ash and 13.4 g – 59 g moisture in the meats. Equally, the minerals showed varied in both the insects and the meats. Statistical comparison of the means of the results showed that the Carbohydrates, the Protein and the Fibre do not differ (P˂0.0) significantly in both the insects and the meats. Similarly Copper, Iron, Sodium, Calcium, Magnesium and Potassium do not differ significantly in the two groups. This suggested that insects as diet when taken in required amount can meet the protein requirement of the human body and can therefore supplement animal meats in our diets.

Phase-Dependent Color Polyphenism in Field Populations of Red Locust Nymphs (Nomadacris septemfasciataServ.) in Madagascar

Pigmentation of the Red locust hopper,Nomadacris septemfasciataServ., was studied in natural conditions in Madagascar in relation to population density. More than one thousand hoppers were collected and described according to a semiquantitative method. A typology is proposed, strictly reflecting the increase in population densities. This correctly translated the progressive evolution of a solitary state into a gregarious state, while passing through several intermediate transiens stages. According to their density, hopper populations consist of a mixture, in various proportions, of several pigment types. The gregarization threshold is estimated at 100,000 hoppers/ha. A slight black spot on the hind femur is the first sign of gregarization. These results should improve the reliability of the information collected by the Malagasy National locust centre when surveying this major pest. They question the rapidity of the gregarization process in natural conditions as well as the stimuli involved.