AN ACTIVE immune system early in life may stunt lifespan, at least in beetles. The findings support the idea that a strong immune system helps a species reach breeding age but brings an earlier death from fighting infections.
, at the University of Sheffield in the UK, and colleagues activated the immune system of mealworm beetle larvae using either dead bacteria or a piece of nylon, introduced to irritate the gut lining. Maximum lifespan was 10 per cent shorter in the 鈥渋nfected鈥� beetles at just 202 days, compared with 224 in the controls.
The reason for early death was clogging of the Malpighian tubules 鈥� structures that perform a similar role to kidneys in humans 鈥� with melanin, which is produced as a result of immune system activation in beetles (PLoS One, ).
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Some suggest that an active immune system early in human life can also lead to a shortened lifespan: 鈥淚t supports our analysis of the 1918 flu epidemic, in which prenatal exposure caused a 25 per cent increase of heart disease 60 years later,鈥� says Caleb Finch of the University of Southern California, Los Angeles.
