Definition of facultatively in US English:

facultatively

adverb

  • See facultative

    • ‘The heterogeneous enrichment among individual worms agrees with reports that this nominal deposit feeder can facultatively filter-feed using a mucus net in its burrow, and that the ability to do so varies among populations.’
    • ‘Among bats, larger species among the Pteropodidae (Old World fruit bats with mass in the range 0.21.5 kg) often glide or soar, and use undulating flight facultatively.’
    • ‘Insects such as ants, wasps and flies from the vicinity are attracted to these rewards and defend the plants facultatively against herbivores.’
    • ‘The adult cowtail stingray of Shark Bay, Western Australia, is a solitarily foraging animal that facultatively groups when resting on shallow, inshore sand flats.’
    • ‘In many, if not all, facultatively social bees, ecological factors such as competition for nesting sites and predation seem to promote social nesting, although genetic differences may also underlie social variation.’