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Effects of ablation of the pars intercerebralis on ecdysteroid quantities and yolk protein expression in the blowfly Protophormia terraenovae
Author(s) -
TANAKA AYAKO,
KUGA YOSHIYUKI,
TANAKA YOSHIAKI,
GOTO SHIN G.,
NUMATA HIDEHARU,
SHIGA SAKIKO
Publication year - 2013
Publication title -
physiological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 57
eISSN - 1365-3032
pISSN - 0307-6962
DOI - 10.1111/phen.12012
Subject(s) - ecdysteroid , vitellogenesis , hemolymph , medicine , biology , yolk , endocrinology , diapause , larva , oocyte , hormone , microbiology and biotechnology , biochemistry , botany , embryo , ecology
Quantities of ecdysteroid are compared in the haemolymph and ovaries of the blowfly Protophormia terraenovae R obineau‐ D esvoidy ( D iptera: C alliphoridae) under reproductive (LD 18 : 6 h at 25 °C) and diapause (LD 12 : 12 h at 20 °C) conditions. The effects of ablation of the pars intercerebralis or ovaries on ecdysteroid quantities and of ablation of the pars intercerebralis on yolk protein expression are examined. Under reproductive conditions, the levels of ecdysteroid in vitellogenic females are high, although the levels in previtellogenic females and females with mature ovaries are low. Under diapause conditions, there are low quantities of ecdysteroid in both the haemolymph and ovaries. Ecdysteroid titres in the haemolymph are not significantly affected by the removal of the ovaries, suggesting that tissues other than the ovaries are also involved in the production of ecdysteroids. Reproductive females in which the pars intercerebralis of the brain is experimentally ablated have ecdysteroid levels that are not significantly different from sham‐operated or intact females. However, yolk protein expression in the fat body is suppressed after removal of the pars intercerebralis. These results suggest that the suppression of ecdysteroid levels in the haemolymph and ovaries is associated with reproductive diapause, and that the pars intercerebralis could play a role in yolk protein synthesis without mediating ecdysteroid production.