pregnancy, males, pregnancies, females, groups, song, matings, calls, transformation, pollen, male, antibody, songs, sperm, signals, cues, antibodies, sites, attraction, regulation, individuals, activities, prey, transfer, odors, activity, organisms, combinations, expression, associations, recombinants, crosses, interactions, recombinations, stimuli, grafts, grains, origin, chimeras, reactions, mating, hybrids, call, dna, predators, signal, fertilization, trees, discrimination, competitors, populations, species, flowers, encounters, deposition, cells, chicks, intruders, pairs, pupae, association, neighbours, female, antiserum, foraging, courtship