Developmental responses of <i>Trichoplusia ni</i> (Lepidoptera: Noctuidae) to parasitism by the ectoparasite <i>Euplectrus plathypenae</i> (Hymenoptera: Eulophidae)

Coudron, Thomas A.; Kelly, Thomas J.; Puttler, Benjamin

doi:10.1002/arch.940130108

Cited by 56 publications

(41 citation statements)

References 38 publications

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“…Most studies have focused on the hypothesis that the wasp or its associated PDV produce molecules which directly reduce ecdysteroid titers by altering processing or release of PTTH Tanaka and Vinson, 1987;Zitnan et al, 1995;Kelly et al, 1998), disrupting ecdysteroid biosynthesis by prothoracic glands (Pennacchio et al, 1998;Pennacchio et al, 2001;Fallabella et al, 2003), or metabolizing ecdysteroids in circulation (Grossniklaus-Burgin et al, 1998;Coudron et al, 1990). An alternative hypothesis is that inhibition of pupation is an indirect response to virus-and/or parasitoid-induced alterations in host growth or nutritional physiology (Thompson, …”

Section: Introductionmentioning

confidence: 99%

Infection by a symbiotic polydnavirus induces wasting and inhibits metamorphosis of the mothPseudoplusia includens

Pruijssers

Falabella

Eum

et al. 2009

Journal of Experimental Biology

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SUMMARYInsect pathogens and parasites often affect the growth and development of their hosts, but understanding of these processes is fragmentary. Among the most species-rich and important mortality agents of insects are parasitoid wasps that carry symbiotic polydnaviruses (PDVs). Like many PDV-carrying wasps, Microplitis demolitor inhibits growth and pupation of its lepidopteran host, Pseudoplusia includens, by causing host hemolymph juvenile hormone (JH) titers to remain elevated and preventing ecdysteroid titers from rising. Here we report these alterations only occurred if P. includens was parasitized prior to achieving critical weight, and were fully mimicked by infection with only M. demolitor bracovirus (MdBV). Metabolic assays revealed that MdBV infection of pre-critical weight larvae caused a rapid and persistent state of hyperglycemia and reduced nutrient stores. In vitro ecdysteroid assays further indicated that prothoracic glands from larvae infected prior to achieving critical weight remained in a refractory state of ecdysteroid release, whereas infection of post-critical weight larvae had little or no effect on ecdysteroid release by prothoracic glands. Taken together, our results suggest MdBV causes alterations in metabolic physiology, which prevent the host from achieving critical weight. This in turn inhibits the endocrine events that normally trigger metamorphosis.

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Section: Introductionmentioning

confidence: 99%

Infection by a symbiotic polydnavirus induces wasting and inhibits metamorphosis of the mothPseudoplusia includens

Pruijssers

Falabella

Eum

et al. 2009

Journal of Experimental Biology

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“…These observations suggest that the venom activates the expression of the storage proteins by acting directly on a particular tissue rather than indirectly via the intact neuroendocrine center. This is similar to the developmental arrest effect of the venom on the larvae which results in arrest of the larval-larval ecdysis process [33]. In particular, these results demonstrate the ability (competence) of early larval stages and isolated tissues of penultimate instar larvae to produce gene products that normally occur in the intact last larval stadium of lepidopteran larvae.…”

Section: Hemolymph Proteins In Ligated Larvaementioning

confidence: 64%

Premature production of late larval storage proteins in larvae of trichoplusia ni parasitized by euplectrus comstockii

Coudron

Jones

1994

Arch Insect Biochem Physiol

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Investigations were conducted to determine the titer of storage proteins in larvae of the cabbage looper, Trichoplusia ni (Hubner), that were parasitized by the ectoparasitoid Euplectrus comstockii Howard (Hymenoptera: Eulophidae). A gradual increase was noted in the titer of the storage proteins present in the hernolymph of parasitized third and fourth instar larvae and in the hemolymph of isolated thoracic and abdominal tissues of fourth instar larvae. The final amount present in parasitized third and fourth instar larvae was similar to thatfound in nonparasitized fifth instar larvae. The stimulation of storage proteins in envenomed larvae demonstrates the ability (competence) of early larval stages to produce a gene product that normally occurs in the last larval stadium of the lepidopteran larval host. The gene expression necessary for storage protein production in isolated tissues may be altered by mechanisms separate from inherent developmental processes and the intact endocrine system. o 1994 WiIey-Liss, Inc.*

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“…The E. comstockii colony was derived from a stock colony collected in Missouri during 1985 to 1989 (Coudron et al, 1990). The wasps were reared on 3rd-and 4th-instar T. ni larvae which, in turn, were maintained on a semisynthetic wheat germ diet (Wilkinson et al, 1972) at 23-26~ LD 12:12, and 40-60% relative humidity (Coudron et al, 1990).…”

Section: Insect Rearing and Weight Determinationmentioning

confidence: 99%

“…Email: gelrnan@asrr.ars.usda.gov Beckage and de Buron, 1993;Gelman et al, 1998, in press). In others, such as T. ni parasitized by Euplectrus plathypenae (Kelly and Coudron, 1990) and Heliothis virescens parasitized by Cardiochiles nigriceps (Pennacchio et al, 1994), hemolymph ecdysteroid levels may increase, but physiologically active 20-hydroxyecdysone is either present at reduced levels or is absent. The current study was undertaken to determine the effects of Euplectrus comstockii venom on the endocrine processes in 9 nubiIalis, an important pest of corn and other vegetables.…”

Section: Introductionmentioning

confidence: 95%

Mode of action of the venom of the ectoparasitic wasp,Euplectrus comstockii, in causing developmental arrest in the European corn borer,Ostrinia nubilalis

Gelman

Kelly²,

Coudron

1997

Invertebrate Neuroscience

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Euplectrus comstockii Howard (Hymenoptera: Eulophidae), is an ectoparasitic, gregarious wasp which parasitizes the larval stage of several important lepidopteran pests. Parasitization of both natural and unnatural hosts prevents molting in the parasitized instar. Here we report the effect of wasp venom on the European corn borer (unnatural host), an important pest of corn and other vegetables. Venom collected from venom glands of adult E. comstockii, when injected into O. nubilalis 5th instars, inhibited the growth rate, development and molting of the injected larvae. The observed effect on molting was dose and age dependent. When 3rd, 4th and 5th instar O. nubilalzs were envenomated by adult wasps, the larvae also were developmentally arrested and failed to undergo a molt. However, 3rd and 4th instars underwent apolysis (separation of the epidermis from the old cuticle) and produced new cuticle. Fifth instars did not. A premolt hemolymph ecdysteroid peak was not observed in these experimental 5th instars, but injections of 20-hydroxyecdysone induced apolysis and new cuticle formation. Envenomated 4th insrars (on becoming pharate 5th instars) exhibited a premolt hemolymph ecdysteroid peak. HPLC/RIA revealed that 20-hydroxyecdysone was present in the hemolymph of these pharate 5th instars. Thus, in the European corn borer, the mode of action of the venom depended upon the instar parasitized. Our results support the presence of a venom component(s) that, in 4th instar hosts, inhibited ecdysis, but did not prevent hemolymph ecdysteroid levels from increasing sufficiently to stimulate apolysis. In 5th instars, the same, or perhaps, a different component(s) of E. comstockii venom prevented the synthesis/release of ecdysteroid by inhibiting a previously unknown molt-regulating physiological event that occurs between days 3 and 4 of the instar.

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Developmental responses of Trichoplusia ni (Lepidoptera: Noctuidae) to parasitism by the ectoparasite Euplectrus plathypenae (Hymenoptera: Eulophidae)

Cited by 56 publications

References 38 publications

Infection by a symbiotic polydnavirus induces wasting and inhibits metamorphosis of the mothPseudoplusia includens

Infection by a symbiotic polydnavirus induces wasting and inhibits metamorphosis of the mothPseudoplusia includens

Premature production of late larval storage proteins in larvae of trichoplusia ni parasitized by euplectrus comstockii

Mode of action of the venom of the ectoparasitic wasp,Euplectrus comstockii, in causing developmental arrest in the European corn borer,Ostrinia nubilalis

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