Journals of Gerontology Series A: Biological Sciences and Medical Sciences, Vol 50, Issue 1 B9-13, Copyright © 1995 by The Gerontological Society of America
A malathion resistance gene associated with increased life span of the rusty grain beetle, Cryptolestes ferrugineus (Coleoptera: Cucujidae)
ND White and RJ Bell
Agriculture Canada, Research Station, Winnipeg, Manitoba.
The life span of the rusty grain beetle, Cryptolestes ferrugineus, was
determined at 30 degrees C, 75% relative humidity (RH) for virgin and mated
adults of a malathion-resistant strain (BC6RR), a malathion- susceptible
strain (SS), the F1 progeny of a cross between resistant females and
susceptible males (RS), and an outbred strain (GV). The BC6RR strain was
derived from the SS strain by incorporating the malathion resistance gene
into the susceptible genome with six backcrosses and recovery of
heterozygous resistant F1 adults between crosses. The mean life span of
virgin, malathion-resistant adults (BC6RR and RS) was 37 weeks; the mean
life span of virgin, susceptible adults (SS and GV) was 32 weeks. Resistant
virgin adults lived significantly longer (15-16%) than susceptible virgin
adults, and mated resistant adults lived significantly longer (3-20%) than
mated susceptible adults (p < .05). Since C. ferrugineus has a
relatively long reproductive period and females with the longest life spans
produce the most offspring, life span can be considered an important
component of fitness in this insect. The malathion resistance gene did not
reduce fitness, and this gene or genes closely linked to it may be
responsible for increasing life span in C. ferrugineus.
