VARIATION IN SIZE AND LIPID-CONTENT OF ADULT SOUTHERN PINE BEETLES, DENDROCTONUS-FRONTALIS ZIMMERMANN (COLEOPTERA, SCOLYTIDAE) IN RELATION TO SEASON

Variations in size, weight, and lipid content of brood adult southern pine beetles, Dendroctonus frontalis Zimmermann, were investigated usi ng a spectrophotometric technique to determine total lipid content of individual beetles. Large seasonal variations in these parameters were found with significant differences occurring between months and years . Patterns of variation, however, were not consistent with those repor ted in previous studies, leading to the conclusion that these variatio ns do not have regular seasonal patterns. Variations in beetle measure ments were not related to tree characteristics. Female beetles, on ave rage, were heavier and contained more lipid than male beetles. The spe ctrophotometric technique used improves on a similar technique recentl y reported. The technique allowed more extensive measurements, includi ng total lipid content, dry weight, and percent lipid content, to be t aken on individual beetles.