Determining the age of free-living insects, particularly of blood-sucking species, is important for human health because such knowledge critically influences the estimates of biting frequency and vectoring ability. Genetic age determination is currently not available. Pteridines gradually accumulate in the eyes of insects and their concentrations is the prevailing method. Despite of their stability, published extractions differ considerably, including for standards, for mixtures of pteridines and even for light conditions. This methodological inconsistency among studies is likely to influence age estimates severely and to hamper their comparability. Therefore we reviewed methodological steps across 106 studies to identify methodological denominators and results across studies. Second, we experimentally test how different pteridines vary in their age calibration curves in, common bed (Cimex lectularius) and bat bugs (C. pipistrelli). Here we show that the accumulation of particular pteridines varied between a) different populations and b) rearing temperatures but not c) with the impact of light conditions during extraction or d) the type of blood consumed by the bugs. To optimize the extraction of pteridines and measuring concentrations, we recommend the simultaneous measurement of more than one standard and subsequently to select those that show consistent changes over time to differentiate among age cohorts.
Das System H,S/NEt, reagiert wie Sulfid [8] und bildet mit zwei Aquivnlenten 1 (R' = R2 = Et) das an der Luft langsam unter H,S-Abspaltung hydrolysierende kristalline, gelbe Thioanhydrid 5 . E x p e r i m e n t e l l e s
N-(Dialkylamino-thiocarbonyl)benziniidothio(selenoester) 2a,b; 3; 4a,b (Weg A ) :Zu einer Losung von 2,7 g (0,06 mol) Natriummethanolat und 2,4 g (0,05 mol) Methylmercsptsn (fur 2a,b) bzw. ?,4 g Ethan-l,2-dithiol (fiir 3 ) bzw. 0,05 mol Methylselenol (fur 4a, b) (durch reduktive Spaltung von Dimethyldiselenid mit NaBH, erzeugt) in ?OO ml getrocknetem Alkohol (MeOH; EtOH) werden 0,05 mol des entsprechenden 1 [3], gelost in 200 ml Aceton, innerhalb von GO min zugetropft. Nach 3stiindigem Riihpen bei Raumtemperatur wird von aiisgeschiedenem NaCl abgesaugt. Die gelben Kristalle des Zielproduktes scheiden sich beim Konzentrieren der Mutterlauge im Rotationsverdampfer ab. 4a, b sind im Kiihlschrank begrenzt hgerfahig.
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