[C#] Only one instantiate object is working, the rest is not.. Help meee

How to say this... I have succesfully spawning an object with the Instantiate But I want the object to spawn every 3 second, so I add script to check every 3 second, spawn one

The spawned instantiate, in this case "spider", when he sees my player, he will run away - The first spawned instantiate is working perfectly like it should (give me message my player is near, and then walks away) - The second, third, and so on able to give me message that my player is near, but it won't move..

Here's My code

 public class EnemySmallNest : MonoBehaviour {
     
     public GameObject enemySpider;
     private GameObject enemySmall;
 
     float startTime = 0;
     private Vector3 currentNestPost;
 
     // Use this for initialization
     void Start () {
         currentNestPost = new Vector3 (transform.position.x, transform.position.y, transform.position.z);    
     }
 
     
     // Update is called once per frame
     void Update () {
 
         startTime += Time.deltaTime;
         
         if (startTime >= 3) {
             enemySmall = Instantiate (enemySpider, currentNestPost, Quaternion.identity) as GameObject; //Spawn Spider
             startTime = 0;
         }
 
     }
 
 }

anyone can help me fix this?