Cuticular Hydrocarbon Synthesis in Relation to Feeding and Developmental Stage in Nymphs of Blattella germanica (Dictyoptera: Blattellidae)

Abstract

D e p a r t m e n t o f E n t o m o l o g y , N o r t h C a r o l i n a S t a t e U n i v e r s i t y , B o x 7 6 1 3 , R a l e i g h , N C 2 7 6 9 5 -7 6 1 3Ann. Entomol. Soc. Am. 9 0 ( 5 ) : 655-663 (1997) ABSTRACT T h e p a t t e r n s o f h y d r o c a r b o n s y n t h e s i s a n d t r a n s p o r t t o t h e e p i c u t i c l e w e r e e x a m i n e d i n m a l e s a n d f e m a l e s o f t h e G e r m a n c o c k r o a c h , Blattella germanica ( L . ) , d u r i n g t h e

Site of synthesis, tissue distribution, and lipophorin transport of hydrocarbons in Blattella germanica (L.) nymphs

“…Moreover, immatures face a repeated challenge of HC synthesis and deposition onto the new cuticle as they pass through the series of molts (six in female B. germanica) to adulthood. The epicuticle of newly eclosed insects is covered with HC synthesized during the previous stadium (Guo and Blomquist, 1991;Young and Schal, 1997), but the course of this synthesis, sites of HC storage, and the transport pathway(s) of new HC to the developing epicuticle remain largely unknown (Schal et al, 1998).…”

Cuticular hydrocarbons as maternal provisions in embryos and nymphs of the cockroach Blattella germanica

“…Maternal hydrocarbons would thus offset such deficiencies and serve to protect young nymphs from excessive water loss. Moreover, only a fraction of each intermolt period is dedicated to hydrocarbon synthesis (Fig.·2B) (Cripps et al, 1988;Young and Schal, 1997) and this process is significantly constrained by both availability of food (Young et al, 1999) and cyclic cellular competency of the oenocytes to produce hydrocarbons . Interestingly, the first instar of the German cockroach is the only mobile stage that can proceed to the next molt largely independent of food intake (Kopanic et al, 2001).…”

“…Surface lipids were extracted from egg cases as described previously (Young and Schal, 1997). Each egg case was immersed in 2·ml n-hexane containing 15·g n-hexacosane as an internal standard, agitated gently for 5·min, and the solvent was decanted into a clean vial.…”

“…First, sodium [1-14 C]propionate was injected into vitellogenic females on day 3. Newly biosynthesized methyl-branched hydrocarbons are thus rapidly radiolabeled (Young and Schal, 1997), transported by lipophorin to the ovaries and then incorporated in embryos and first-and second-instar nymphs. About 7.05% of the injected propionate was used for hydrocarbon production.…”

“…Between 4 and 31·days after [1- 14 C]propionate injection into 5-day-old females, >95% of the radioactivity in lipids of embryos and nymphs was associated with hydrocarbons ( Fig.·4). Because the propionate pool is rapidly fixed into macromolecules within 4·h of injection (Young and Schal, 1997), transfer of radiolabeled propionate to the oocytes is extremely unlikely. Thus, it appeared that maternal hydrocarbons were not degraded at any embryonic or post-embryonic stage.…”