Abstract: Disclosed are novel strains of Xenorhabdus bovienii deposited with NCIMB under accession numbers NCIMB 40985 and NCIMB 40986 which are a source of orally acting pesticides. Also disclosed are pesticidal agents which are (i) obtainable from a X. bovienii strains; (ii) have oral insecticidal activity against one or more species of insect of the order Lepidoptera, Coleoptera or Homoptera; (iii) are substantially heat stable to 50° C.; and (iv) act synergistically with B. thuringiensis cells as an oral insecticide. The invention further makes available nucleic acids encoding these and variant toxins, plus vectors, host cells and plants transformed with the same. Also disclosed are insecticidal polypeptides (and antibodies raised to them) and compositions, plus methods of using all of these materials for the control of pests, particularly insects.