Effects of temperature and supplementary food on the development and fecundity of the Eulophid parasitoid Tetrastichus howardi on Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract

Tetrastichus howardi (Olliff), a pupal endoparasitoid of the major agricultural pest Spodoptera frugiperda (J.E. Smith). Laboratory studies were conducted to determine the effect of the temperature and supplementary food on the development and reproduction of this parasitoid on S. frugiperda pupae. The results revealed that T. howardi could complete the life cycle under all five tested temperatures (18, 22, 26, 30 and 34 °C), with the most extended longevity (female: 42.83 days; male: 24.37 days) and the most prolonged developmental duration (egg-adult) (52.33 days) at 18 °C. Parasitoids that were kept at 26 °C had the greatest parasitism rate (72.67%) and the highest net reproductive rate R0 (56.35), and those maintained at 34 °C had the highest emergence rate (92.03%), the greatest number of emerged progeny (58.40) and the highest intrinsic rate of increase rm (0.310 d−1). Feeding on honey, glucose, and sucrose significantly increased the adult longevity and the progeny production of T. howardi but showed no significant effects on parasitism rate, emergence rate, the developmental duration of progeny, or sex ratio. Parasitoids that fed on glucose lived the longest (21.23 days), and the highest emerged offspring occurred when honey is provided (57.77). These results are instructive for the mass-rearing of T. howardi and field control of S. frugiperda.