The Collaborative International Dictionary of English v.0.48:

Insectivorous \In`sec*tiv"o*rous\, a. [See Insectivora.]
   Feeding or subsisting on insects; carnivorous. The term is
   applied:
   (a) to plants which have some special adaptation for catching
       and digesting insects, as the sundew, Venus's flytrap,
       Sarracenia, etc.
   (b) to the Insectivora, and many bats, birds, and reptiles.
       [1913 Webster]

WordNet (r) 3.0 (2006):

insectivorous
    adj 1: (of animals and plants) feeding on insects [ant:
           carnivorous, herbivorous, omnivorous]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "insectivorous":
   cannibal, cannibalistic, carnivorous, commensal, dietetic, dining,
   eating, feeding, flesh-eating, fruitarian, gastronomic, gluttonous,
   grain-eating, graminivorous, granivorous, grass-eating,
   herbivorous, insect-eating, lactovegetarian, man-eating,
   meat-eating, mensal, nourishing, nutritious, omnivorous,
   omophagous, pantophagous, phytivorous, phytophagous, plant-eating,
   postprandial, prandial, predacious, preprandial, vegetable-eating,
   vegetarian