it's a cicada.. they spend 17 years of their lives living off
the sap of trees underground, mature then come out, make a lot of
noise, breed, lay eggs then die...
other cicadas have 13 years or life cycles of prime
numbers...
so it is theorised that they had predators or parasites with
similar length of life cycles..
say, the parasite has a life cycle of 2 years, then the cicada will
want to avoid a life-cycle which is divisible by 2.. if the
parasite has a life cycle of 3 years, then the cicada wants to
avoid a life-cycle which is divisible by 3..
if the parasite has a 2 year life-cycle, the cicada, having a 17
year life-cycle, will only meet every 34 years.. and so on.. if the
parasite has a 16 year life-cycle, they will only meet every 272
years..
in order to fight back, the parasite has only 2 life-cycles to
increase the frequency of coincidences.. it has 2 ways.. get an
annual life cycle or reach a 17 year life-cycle..
if annual, there are no cicadas for it to feed on for 16
life-cycles..
if it tries to get to a 17 year life-cycle, it would need to evolve
through the 16 year life-cycle then jump to 17... which means at
some stage of the evolution, they do not meet for 272 years.. by
then, the parasite would probably have died out 
