Larval Temperature in Brood Clumps ofBombus Pascuorum(Scop.)

Abstract

Summary For 21 larvae cocoon diameter (4·3 to 8·1 mm) was positively correlated with mean temperature at the fourth instar stage (27·06, SE ± 0·17 to 31·89, SE ± 0·15°C; r = 0·59, Pr = −0·53, P<0·05). Larvae located centrally in a brood clump generally experienced higher and more stable temperatures (30·89 ± 0·39°C; CV, 2·77 ± 0·16) than those located peripherally (29·10 ± 0·34°C; CV, 3·26 ± 0·13). Pupal weight was highly correlated with centrally located pupal cocoons of 7·27, SE ± 0·30 mm in diameter and peripheral cocoons of 5·78, SE ± 0·28 mm in diameter (r = 0·95, P<0.001).