The relationship between diet, aging and longevity in an orb-web spider

The macronutrient composition of natural diets varies and affects aging and longevity of a variety of taxa. The relationship between diet and longevity is more prominent in model species than wild populations suggesting this may be a laboratory artefact. I applied dietary and protein restriction to understand how diet influences aging and longevity in a non-model species, the orb web spider Argiope keyserlingi. To assess whether longevity and performance vary with the amount and type of food, I set up treatments that manipulated how much food and protein the spiders received in a random assignment. My initial experiment showed that the amount of food (standard vs half the amount of food), did not affect longevity. In a subsequent experiment, I compared the spiders' performance, such as running speed, weight and web area on a weekly basis between a high and low protein feeding treatment. My results showed that there were no significant interactions between the amount of protein in the spiders' diet and its effects on a spiders' lifespan. However, spiders on the low protein diet built significantly smaller webs than their high protein counterparts, but as spiders aged, overall, they built smaller webs. Overall patterns of aging were affected by the duration of the treatment, but diet only affected the web area. In conclusion, my experiments only weakly support the notion that diet affects aging, which is prominently found in model species and less common in wild populations.