VARIATION IN FEMALE SOUTHERN PINE-BEETLE SIZE AND LIPID-CONTENT IN RELATION TO FUNGAL ASSOCIATES

Female southern pine beetles, Dendroctonus frontalis Zimmermann, may p ropagate two species of symbiotic fungi in a prothoracic mycangium. Fe males can carry either Ceratocystiopsis ranaculosus Bridges and Ferry or an unnamed basidiomycete or both; some carry no fungi. Thus, female s can be categorized into one of four groups based on mycangial conten t. We examined size and lipid content of emerging brood adult females based on these mycangial fungal classes. Female beetles carrying the b asidiomycete, either alone or in combination with C. ranaculosus, were larger, heavier, and contained more lipid than did females carrying o nly C. ranaculosus. Size and lipid content also varied by season, as d id the number of females carrying different fungal combinations. Regre ssion analysis showed that variation in the occurrence of the basidiom ycete was significantly related to variation in averages of beetle siz e and lipid content measurements.