Effects of three prey species on ovary development and vitellogenin content of Eocanthecona furcellata （Wolff）

Objective This study aimed to investigate effects of prey nutrition and mating on ovarian development and vitellogenin （Vg） content in female Eocanthecona furcellata （Wolff）. Physiological analysis and evaluation of the reproductive capacity and prey consumption efficiency of Eocanthecona furcellata （Wolff） were conducted to provide a theoretical basis for its mass rearing of Eocanthecona furcellata （Wolff）.Method The ovaries of female Eocanthecona furcellata （Wolff） adults were dissected using wax plates and a binocular stereomicroscope. The length， width and egg count of ovarioles of female Eocanthecona furcellata （Wolff） fed on larvae of Spodoptera frugiperda （J. E. Smith）， Spodoptera litura （Fabricius）， and Tenebrio molitor （L.） were recorded at 0， 5， 10， and 15 days post-emergence using ultra-depth-of-field digital stereomicroscope. The vitellogenin （Vg） content in female adults of Eocanthecona furcellata （Wolff） fed on different prey was determined at 0， 5， 10， 15， 20， and 25 days post-emergence under mated and unmated conditions using assay kits. Differences in ovariole length， width， egg count， and Vg content of female Eocanthecona furcellata （Wolff） adults were analyzed using one-way analysis of variance （ANOVA） and least significant difference （LSD） test.Result The results showed that each female adult Eocanthecona furcellata （Wolff） possessed one pair of ovaries， with each ovary composed of seven telotrophic ovarioles. The age at emergence and prey diet of Eocanthecona furcellata （Wolff） influenced the progression of ovarian development but did not affect the number of ovarioles. The results also indicated that when fed on the same prey， female Eocanthecona furcellata （Wolff） fed on larvae of Spodoptera litura （Fabricius） or Spodoptera frugiperda （J. E. Smith） exhibited significantly higher numbers of mature eggs in their ovaries at 10 and 15 days old compared to those at 0 and 5 days old （P<0.05， the same below）， while the length and width of their ovarioles were significantly greater than those of 0-day-old individuals. For female Eocanthecona furcellata （Wolff） adults fed on Tenebrio molitor （L.） larvae， significant differences in the number of mature eggs and ovariole length and width were observed at 15 days old compared to 0- and 5-day-old individuals. When fed on different prey， female adults of Eocanthecona furcellata （Wolff） fed on Spodoptera frugiperda （J. E. Smith） larvae exhibited significantly longer ovariole lengths at 0 days old compared to those fed on Spodoptera litura （Fabricius） larvae， and significantly longer ovariole lengths at 5 days old compared to those fed on Tenebrio molitor （L.） larvae. At 10 days old， the ovariole width of adults fed on Spodoptera frugiperda （J. E. Smith） larvae was significantly greater than that of those fed on Tenebrio molitor （L.） larvae. When fed on the same prey， Vg content in mated female adults fed on Spodoptera frugiperda （J. E. Smith） larvae at 10 and 20 days old was significantly higher then that in unmated individuals. The Vg content in mated female adults fed on larvae of Tenebrio molitor （L.） and Spodoptera litura （Fabricius） at 15 and 20 days old was significantly higher than that in unmated ones， while Vg content in mated female adults fed on Spodoptera frugiperda （J. E. Smith） at 10 and 25 days old was significantly higher than that in unmated ones fed on the other two prey species. The Vg content in unmated female adults fed on larvae of Spodoptera litura （Fabricius） and Tenebrio molitor （L.） and at 5 days old was significantly higher than that in the ones fed on Tenebrio molitor （L.） larvae， while the Vg content in unmated female adults fed on Spodoptera litura （Fabricius） larvae at 15 and 25 days old was significantly lower than that in the ones fed on Spodoptera frugiperda （J. E. Smith） larvae.Conclusion Eocanthecona furcellata （Wolff） fed on Spodoptera frugiperda （J. E. Smith） larvae exhibits enhanced ovarian deve-lopment， faster yolk accumulation， and a higher Vg content， indicating that Spodoptera frugiperda （J. E. Smith） larvae have a more pronounced promoting effect on the ovarian development of female Eocanthecona furcellata （Wolff） adults compared to the other two prey species.