Abstract: 【Aim】 This study aims to determine the morphological and biological characteristics including developmental duration and adult fecundity of Trigonotylus coelestialium, so as to provide a theoretical basis for its prediction and scientific control. 【Methods】 T. coelestialium was bred with corn grains at the filling stage as the food under the indoor natural variable temperature (22.0-28.1℃) and the constant temperature of 25℃, respectively, in Zhengzhou, Henan Province, central China during September-October, 2021, and the morphological characteristics of T. coelestialium at different developmental stages were observed and recorded. The biological indexes including the duration of different developmental stages, survival rate, adult longevity and female oviposition quantity were measured. 【Results】 The egg mass of T. coelestialium is deposited in the inner glume of corn grain. The egg is cylindrical and slightly curved to one side. The antennae of the 1st instar nymphs are reddish, and the red color becomes obvious with the increase of nymphal instar. At the 5th instar nymphal stage, three clearly visible red longitudinal lines appear on the 1st segment of antennae. The 3rd instar nymphs have evident wing buds. The ovipositor of the female adult is long valvular and lies flat in the groove of genital segments. Under the indoor natural variable temperature, the egg duration of T. coelestialium was 6.27 d with the egg hatching rate of 89.90%, the 1st-5th instar nymphal duration was 2.80, 2.33, 2.70, 2.77 and 3.90 d, respectively, and the total nymphal duration was 14.50 d with the total nymplal survival rate of 85.97%. The pre-oviposition period of female adult was 4.43 d, the oviposition duration was 13.93 d, and a total of 82.55 eggs in 19.47 egg masses were produced by a single female under the indoor natural variable temperature. Under the constant temperature of 25℃, the egg duration of T. coelestialium was 7.73 d with the egg hatching rate of 81.13%, the 1st-5th instar nymphal duration was 2.17, 1.90, 1.77, 1.90 and 2.93 d, respectively, and the total nymphal duration of T. coelestialium was 10.67 d with the total nymphal survival rate of 71.84%. The pre-oviposition period of female adult was 4.17 d, the oviposition duration was 11.27 d, and a single female laid 72.22 eggs in 21.17 egg masses under the constant temperature of 25℃. 【Conclusion】 The morphological characteristics of the 1st antennal segment of the 5th instar nymph and adult of T. coelestialium can be used to distinguish it from other species of Trigonotylus. The developmental characteristics of the wing bud of T. coelestialium can be used to distinguish its nymphal stage. Variable temperature prolongs the nymphal duration and adult longevity of T. coelestialium, and increases its egg laying capacity and egg hatching rate.

Key words: Trigonotylus coelestialium, morphology, life history, developmental duration, adult longevity, fecundity