In the case of "T. b. brucei" infecting "G. p. gambiensis", during this time the parasite changes the proteome contents of the fly's head. This may be the reason/a reason for the behavioral changes seen, especially the unnecessarily increased feeding frequency, which increases transmission opportunities. This may be due in part to the altered glucose metabolism observed, causing a perceived need for more calories. (The metabolic change, in turn, being due to complete absence of glucose-6-phosphate 1-dehydrogenase in infected flies.) Monoamine neurotransmitter synthesis is also altered: Production of aromatic L-amino acid decarboxylase - involved in dopamine and serotonin synthesis - and α-methyldopa hypersensitive protein was induced. This is very similar to the alterations in "other" dipteran vectors' head proteomes under infection by "other" eukaryotic parasites of mammals, found in another study by the same team in the same year.