1. Habits: red nematodes have the characteristics of hermaphrodite and ectoparasite fertilization, and they usually live in a group, which can increase the chances of fertilization among each other and improve the reproduction ability.

2. Moisture effects: When the water content is high, the red nematodes tend to gather in groups in the water, this is because too much water will weaken their contact with the oxygen around them, causing them to look for safer habitats.

3. Thermoregulation: When the water is cooler, red nematodes will choose to clump together in warmer areas so that they can maintain their body temperature and avoid being harmed by the cooler environment, while when the water is warmer, they will disperse and seek cooler areas.

4. Protecting themselves: In the water, red nematodes can be attacked from other organisms, and huddling together increases defenses and reduces the risk of predation.

5. Nutritional needs: red nematodes need to consume an abundance of nutrients as they grow, and hugging makes it easier for them to interact with other beneficial organisms to get more nutrients.

All in all, the reason why red nematodes like to clump together may be a combination of factors such as adapting to the environment, protecting themselves, and meeting their growth needs.