839
Parasitic ant species enter the colonies of host ants and establish themselves as social parasites ; species such as " Strumigenys xenos " are entirely parasitic and do not have workers , but instead , rely on the food gathered by their " Strumigenys perplexa " hosts .
 animal: Strumigenys xenos
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 animal: Strumigenys xenos