Development and thermal requirements of Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) reared on Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) pupae

Abstract

All living organisms’ vital processes are affected by environmental temperature and the knowledge of its effects is fundamental for planning the use of parasitoids in biological control programs. Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) development and thermal requirements were determined on Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) pupae. Each pupa of this host, aging 0-24 hours was submitted to parasitism by six females of T. diatraeae for 24 hours and then transferred to acclimatized chambers at 18, 20, 22, 25, 28, 30 and 32 oC until parasitoid emergency. T. diatraeae biological cycle length (egg-adult) reduced from 37.72 to 16.00 days when temperature was increased from 18 to 30 oC, respectively. The parasitoid emergency and its progeny were greater in the temperature range of 22 to 25 oC. Temperature rise increased the number of females and, consequently, changed the parasitoid sex ratio. Head capsule width of T. diatraeae females and males progenies was similar among temperatures.Threshold temperature and thermal constant were 8.4 °C and 328.41 degrees-day, respectively. Temperatures above 22 or below 25 ºC negatively influenced T. diatraeae biological parameters.