Fun with Science Club®


			Are experienced spiderlings at the front of the food line? Carrie Straight 05.03.01 Animals have to eat to survive, and most have to find their own food. The foraging success of young animals, insects and spiders included, will determine if they survive. The ability of young animals to learn while foraging may be very important especially if food sources change. Douglass Morse was interested in newly emerged spiderlings. He wanted to know the answers to many questions, including: Do these spiderlings learn and do they remember the things they learn as they age? Is there a difference between broods (spiderlings emerging from the same egg sac are a brood)? To answer these questions, he collected egg-sacs from the wild and raised the crab spiders (Misumena vatia) in a laboratory. He randomly took 8 newly emerged spiderlings from the first group of egg sacs. He put each spiderling into its own jar. To test if the spiderlings got better at hunting over time, he allowed them to forage once every third day, until they made 6 runs. The spider and a fruit fly were placed together in a petri dish (a small dish with a lid). They watched the spiders to see how long it took them to move to face the fly and the time it took for the spiderling to capture the fly. The spiderlings moved to face the fly faster as the number of trials they were in increased. There were no differences between broods, which means that spiderlings from one egg sac were not different in their ability to face-off a fly from spiderlings from other egg sacs. The spiderlings also learned to capture prey faster as they went through the trials. These tests revealed that spiderlings do learn and become better hunters over time.


			Morse, Douglass H. 2000. The effect of experience on the hunting success of newly emerged spiderlings. Animal Behaviour 60: 827-835.