11.   The food-finder might instead single out one other nest mate, and then lead it alone back to the food source.

12.   These schemes permit efficient recovery of water and oxygen but leave the problem of a food source unanswered.

13.   They match the recruiting party to the size of the food source.

14.   Vitamin E is available from so many food sources that no normal diet could possibly be deficient in it.

15.   When, for instance in Solenopsis, the food source is so large that many ants are needed, mass-acting pheromones are released.

16.   Old house sites are regularly revisited as important food sources.

17.   Along with providing cover for fish, the trees also provide habitat for aquatic insects, essential food sources during the early stage of most fish species.

18.   And in pursuit of the new food sources available to them, they may have roamed far beyond the limits of their ancestral species.

19.   And the woodchuck has always been an important food source for coyotes, foxes, bobcats and other predators, including man.

20.   Bees pollinate alfalfa, which is the chief food source for cows.