Factors affectingLocusta migratoria migratorioidesegg development and survival in the Lake Chad basin outbreak area

Abstract

Abstract Environmental factors affecting egg development and survival in Locusta migratoria migratorioides (Reiche and Farimaire) (Orthoptera: Acrididae) were examined for four seasons in three soil habitats in the Chad basin outbreak area. During the early rainy season eggs survived in sandy habitats only; the survival rate was 29.2%. The fastest rate of egg development occurred in this season, as indicated by an incubation period of 9.5 days, which coincided with the highest air temperature (29.8–36–2°C) in the area. The lowest development rate occurred during the harmattan when incubation lasted 24 days in clay, the only suitable soil for egg survival (11.4%) during the season. The slow rate of development coincided with the lowest air temperatures, which ranged from 19.2 to 25.6°C. During the main rainy season eggs survived in all the three habitats and the development rates were intermediate to those in the two seasons already mentioned. Incubation lasted 13.6 days in sand, 16.0 days in sandy‐clay lo...