THE EFFECT OF PREY DEFENSE ON THE FUNCTIONAL RESPONSE OF <i>PODISUS MODESTUS</i> (HEMIPTERA: PENTATOMIDAE) TO DENSITIES OF THE SAWFLIES <i>NEODIPRION SWAINEI</i> AND <i>N</i>. <i>PRATTI BANKSIANAE</i> (HYMENOPTERA: NEODIPRIONIDAE)

Abstract

Abstract Experiments were carried out to determine the functional response of Podisus modestus (Dallas) to densities of two colonial species of jack pine sawfly, Neodiprion swainei (Middleton) and N . pratti banksianae (Rohwer). Two types of functional response curve were exhibited by the pentatomids, a domed response curve and a negatively accelerated curve.The domed response was caused by the more effective defense reactions of the sawfly larvae at higher densities.An equation is proposed for the domed response curve. The implications of the domed functional response are discussed in relation to the social behavior of these sawflies.