GALLERY CONSTRUCTION AND OVIPOSITION BY <i>IPS CALLIGRAPHUS</i> (COLEOPTERA: SCOLYTIDAE) IN RELATION TO SLASH PINE PHLOEM THICKNESS AND TEMPERATURE

Abstract

Abstract Reproductive performance of Ips calligraphus (Germar) in typical slash pine, Pinus elliottii Engelm. var. elliottii , bark slabs with phloem thicknesses ranging from 0.5 to 4.0 mm was studied at 20°, 25°, and 30 °C during the fall (1981) and summer (1982) seasons by means of radiography and slab dissection. Oviposition rate (eggs/day) and egg density (eggs/cm) were positively correlated with both phloem thickness and temperature, being greatest with a combination of thick phloem (3–4 mm) and warm temperature (30 °C). Gallery construction rate (cm/day) was positively correlated, and length of initial egg-free gallery was negatively correlated, with temperature. Depth of xylem-etching was negatively correlated with phloem thickness. Reproductive performance, as measured by oviposition rate and egg density, was greater in the summer study than in the fall study under similar conditions of phloem thickness and temperature. Nutritional, physical, and seasonal characteristics of xylem, phloem, and outer bark are discussed in relation to the above findings.