Alterations in the ecdysteroid and juvenile hormone esterase profiles of Trichoplusia ni parasitized by the polyembryonic wasp Copidosoma floridanum

Abstract

Trichoplusia ni parasitized by Copidosorna floridanurn weighed more in the fourth and fifth instar than unparasitized controls. While parasitized and unparasitized fourth-instar larvae molted at the same time, parasitized fifthinstar larvae ceased feeding and initiated wandering 1 day later than unparasitized fifth-instar larvae. Measurement of hernolymph ecdysteroid, juvenile hormone esterase (JHE), and protein titers suggested that the delay in wandering had an endocrinological basis. Ecdysteroid titers of parasitized and unparasitized fourth-instar larvae were similar, but the ecdysteroid titer in parasitized fifth-instar larvae rose about 24 h later than in unparasitized fifth-instar larvae. Two major peaks of JHE activity occurred in unparasitized fifth-instar larvae, but only one occurred in parasitized fifth-instar larvae. ]HE activity coincided on the first day of the fifth instar (L5D1) in both parasitized and unparasitized fifth-instar larvae; however, activity peaked and fell later in parasitized individuals. Few differences were noted in the hernolymph protein levels of parasitized and unparasitized hosts. Ligation of parasitized T. ni between the head and prothorax adversely affected C. floridanurn development. Ligation before or immediately after ecdysis to the fourth instar inhibited differentiation of the C. floridanurn morulae. C. floridanurn ecdysed to the second instar or pupated in hosts ligated prior to wandering in the fifth instar, but the number of progeny that pupated and emerged as adult wasps was reduced relative to unligatured controls.

Deep sequencing-based transcriptome analysis of Plutella xylostella larvae parasitized by Diadegma semiclausum

“…Considering that ecdysteroids are required to trigger expression of ecdysteroid regulated protein [62], and that parasitism in general leads to reductions in ecdysteroid titres [54,63-66], down-regulation of ecdysteroid regulated protein is expected.…”

Down-regulation of juvenile hormone esterase and arylphorin production inHeliothis virescens larvae parasitized byMicroplitis croceipes

“…Host juvenile hormone esterase (JHE) activity is reduced in a number of parasitoid-host systems (Beckage and Riddiford, 1982;Dahlman et al, 1990;Hayakawa, 1990;Strand et al, 1990;Zhang et al, 1992). In parasitized insects, hemolymph titers of storage proteins (arylphorins) can be either elevated (Jones et al, 1985(Jones et al, ,1986Jones, 1989;Kunkel et al, 1990) or depressed (Beckage and Kanost, 1993;Shelby and Webb, 1994;Fathpour and Dahlman, 1995).…”

Biochemical and developmental alterations of Heliothis virescens (F.) (lepidoptera, noctuidae) larvae induced by the endophagous parasitoid Cardiochiles nigriceps viereck (Hymenoptera, braconidae)

“…Ligations on day 2 were intermediate. A similar time-related increase of parasitoid development in ligated host larvae has been reported also for Copidosorna floridanurn (Ashmead) [26] and Campletis sonorensis (Cameron) 1271.…”