Temperature-dependent development models describing the effects of temperature on the development of Spodoptera eridania

Background: The southern armyworm, Spodoptera eridania, is a polyphagous species native to the American tropics that recently invaded Africa. Knowledge of the impact of temperature on its development and survival is important to understand the risks of this species spreading to other regions and to develop phenological models for pest management. This study evaluated the effects of temperature on the development and survival of S. eridania and selected mathematical models to simulate its development.

Results: The southern armyworm completed its development between 15 and 32 °C, but eggs did not hatch at 34 °C. Lower survival and higher rates of deformities in adults were recorded at 15 and 32 °C. Among the ten mathematical models evaluated, Briere-2, Lactin-2 and Shi were considered suitable for describing the temperature-dependent development rate of S. eridania. The lower thermal threshold estimated by these models for the egg to adult life cycle ranged from 10.8 to 12.1 °C, whereas the upper threshold ranged between 33.9 and 35.0 °C.

Conclusions: The southern armyworm can develop within a wide range of temperatures, which partially explains its wide distribution in regions with different climatic conditions, and demonstrates its potential to occur in regions outside its native range. Our findings can be employed in the development of management strategies using the selected models to predict the occurrence of S. eridania in the field and determine the most effective times to implement control measures.