Wolf Spider

What Environment do Wolf Spiders Prefer to Live in and What is Their Response to a Change in Environment?

Abstract

What environment do wolf spiders prefer to live in and what is their response to a change in environment? After performing experiments on wolf spiders it was determined that they prefer to reside in an area covered with leaves over an area devoid of any material. It was also determined that temperature plays a role in how much weight a spider can gain. As temperatures lower spiders on average put on less weight than spiders in warmer temperatures. The wolf spiders in my experiment also showed a response in the form of movement to immediate fluorescent lighting. Size was shown to be a determining factor in the time taken for wolf spider interactions with other wolf spiders.

Introduction

Wolf Spiders are ground dwelling spiders that do not form webs as a method of capturing prey. They rely on their eye sight to spot their prey, which consists mainly of other insects. Wolf Spiders have a easily recognizable eye arrangement consisting of four small eyes along a bottom row, then two larger eyes above that row and finally two large eyes placed almost directly on top of their heads. The bite of a wolf spider can be painful, but is not considered poisonous to humans. A study of wolf spider bites done in Brazil found that mild pain was the predominant symptom of patients bitten by wolf spiders1.

After observing wolf spiders in captivity for a while I came up with three hypothesis to test. Wolf Spiders exhibit a significant amount of movement in response to fluorescent light. The mass of wolf spiders changes significantly when exposed to lower temperatures. When placed in the same area, wolf spiders of different sizes interact significantly faster than wolf spiders of the same size.

Methods

To capture wolf spiders I went to a running path across from the Levin School of Law after sunset. Using a flashlight I was able to scan the surrounding wooded area for the reflective eye shine of wolf spiders. After spotting a set of eyes I would locate the spider and place it in a square plastic container measuring 17.8cm2 by 6.35 cm deep. Each spider I caught was housed in its own container.

The first experiment I performed was a test of the spider's response to immediate fluorescent light. To test this I first turned off all the lights in my room except a small light in the back of the room and then turned on a fluorescent desk lamp immediately over the top of the spiders enclosure. The spider movement was measured with a ruler. The spiders used in this experiment were observed to be moving less than 1 cm over a period of 20 seconds prior to the experiment being performed.

To determine how much temperature affects weight gain in wolf spiders I first weighed the each spider individually on a scale. Then the spiders were placed into one of three different temperature environments. The first group was left in my apartment at room temperature, 74 degrees. The second group was placed into a small refrigerator with the temperature set at 64 degrees and the third group was placed into a refrigerator at 54 degrees. All three groups were feed one live ant every two days. After a period of 2 hours if the ant had not been eaten it was taken out. After a period of 2 weeks the spiders were reweighed to determine weight gain or lose.

The third experiment was designed to determine how long it would take spiders of different sizes to interact. I defined interact as any type of physical contact made between the spiders. A spider had to be at least twice as large as another spider to be different in size. Same size spider interaction was used as the control group. Spiders were put into the same container and stop watch was used to track the amount of time it took for interaction. This was done with same size and with different size spiders.

The last experiment involved divided the plastic containers the spiders were housed in into two halves. One half contained leaves and the other half had nothing covering the bottom of the container. Over a period of ten days, twice a day, the position of two spiders was recorded.

Results

Figure1. Shows the number of times each spider was found in either leaves or on the side without leaves.