Hi,

I don't think insects have melatonin. Sure, there is a so-called Periplaneta melatonin receptor in the NCBI database, but do a BLAST on it and you will find that it is something different.

There are also older publications in which people measured melatonin in insects using RIAs. Don't trust that data, false positives in this type of assay are very common.

If this comes as a shock to you, try the melatonin antisera on tissue sections of vertebrate tissues that are known to produce melatonin. This should show you that the antibody works.

For more information you can contact me at

jan.veenstra[at]u-bordeaux.fr even in Spanish.

I agree with Jan. We have not been able to detect/quantify melatonin from Apis mellifera brain samples using our MS method. Either melatonin is not present at all or it is present below our detection limit of 7pg.

What about the enzymes that synthezise melatonin. There are several genomes sequenced. Did you find an AANAT and HIOMT analogue in the data? That would indicate to you whether melatonin is made in the insect brain. It looks that you can find AANAT in insects, but any insect HIOMT has been detected and reported in the Protein Database. Therefore, since this enzyne seems indispensable for the melatonin synthesis, it is most improbable that insects synthezise melatonin.

Hi all,

Divya Ramesh we have successfully detected and quantified melatonin in aphids by LC-MS/MS with LOD 1 pg/mg and LOQ 5 pg/mg. The method is publishedArticle Determination of Melatonin in Acyrthosiphon pisum Aphids by ...

I guess you took into account the possibility that melatonin levels may change along the day/night cycle. But just in case, I would suggest to sample at different moments to make sure you are not measuring samples in which melatonin levels are at minimum.