Oosorption in the Endoparasitoid,Pteromalus puparum

Abstract

Oosorption is the resorption of oocytes in the ovaries, and is usually induced by environmental stress. It has been demonstrated in some insect species, but overall the mechanisms of oosorption are poorly understood. In this study, the oosorption in the endoparasitic wasp, Pteromalus puparum L. (Hymenoptera: Pteromalidae), was observed in response to starvation. To explore the details of oosorption in P. puparum, both levels of hemolymph vitellogenin and ovarian vitellin were determined using sandwich ELISA. The results indicated that both levels of vitellin and total protein in the ovaries were significantly decreased 48 h after eclosion in starved P. puparum, while those of vitellogenin and total protein in the hemolymph were increased. In addition, observation of the ultrastructure of mature oocytes in the ovarioles revealed changes in yolk protein content. Those protein yolk spheres and lipid yolk spheres that had accumulated in the oocytes, were transferred out of the oocytes of starved females. It was assumed that once oosorption was induced in P. puparum, vitellin in the oocytes was transported outside and released into the hemolymph. This information helps to elucidate a mechanism of oosorption in insects.

OVARIAN NUTRITIONAL RESOURCES DURING THE REPRODUCTIVE CYCLE OF THE HEMATOPHAGOUSDIPETALOGASTER MAXIMA(HEMIPTERA: REDUVIIDAE): FOCUS ON LIPID METABOLISM

“…In the endoparasitoid Pteromalus puparum , the transition from vitellogenesis to oosorption proceeded with a diminution in size of lipid droplets, which in turn were also found at the periphery of the oocytes. Such an organization of the lipid store was attributed to a transfer of the ovarian nutrients to the hemolymph, thus providing resources to enhance the survival of the insect (Guo et al., ). Although we do not present evidences supporting ovarian lipid recycling through follicular atresia in D. maxima , a similar mechanism could be operating in this species.…”

Asymmetric effects of adult nutrition on reproductive success of male and female Diaeretiella rapae (Hymenoptera: Aphidiidae)

“…At 5-6 days old, egg load is much higher in honey-fed females than water-fed females. This again suggests that females lose eggs if unable to acquire nutrition for somatic maintenance, probably through resorption (Heimpel et al, 1997;Jervis et al, 2008;Guo et al, 2011). Because no significant increase is found in the egg count in 3-4-day-old versus 5-6-day-old honey-fed D. rapae females, it is likely that water-fed females have resorbed their eggs.…”

Ontogeny and reproductive biology of Diadegma semiclausum (Hym.: Ichneumonidae), a larval endoparasitoid of Diamondback Moth, Plutella xylostella (Lep.: Plutellidae)

“…In contrast to our study, Ghara and Borges (2010) had shown that the Apocryptophagus agraensis (proovigenic parasitoid) produces fewer but larger eggs over her lifetime. Poor environmental conditions including host scarcity, starvation and mating delay cause some parasitoid wasps to resorb yolk material from mature oocytes during their lifetime to fuel somatic maintenance and/or prevent ovigenesis shut down (Jervis and Kidd, 1986a,b;Guo et al, 2011). Thus oosorption serves to reallocate resources (Rosenheim et al, 2000;Jervis et al, 2005;Barrett et al, 2008).…”

“…One of the important life-history variables that correlate with ovigeny index is parasitoid egg resorption capability (Jervis et al, 2005). Egg resorption of oocytes in the ovary defined as oosorption (Asplen and Byrne, 2006;Jervis and Kidd, 1986a,b;Guo et al, 2011) is induced by environmental stress including host or food scarcity (Jervis et al, 2001;Guo et al, 2011) and mating delay (De Souza et al, 2007). However, information on oosorption in D. semiclausum remains deficient and requires further study.…”