AGE-SPECIFIC MATING ACTIVITIES OF MEXICAN RICE BORERS (LEPIDOPTERA, PYRALIDAE)

Occurrence, timing within the scotophase, and duration of mating, as w ell as timing within the scotophase of calling by females, were observ ed in the laboratory for pairs of all age combinations of 0- to 5-d- o ld male and female Eoreuma loftini (Dyar). Also, occurrence of mating of 1- to 5-d-old E. loftini females was examined on mating stations in commercial sugarcane (Saccharum spp.). Percentage of mating moths in the laboratory ranged from 67.3 (4 d old) to 78.7% (1 d old) for femal es and from 56 (0 d old) to 81.3% (5 d old) for males. Occurrence of m ating generally increased with male age. Mating was least likely to oc cur when one sex was very old and the other very young. Females called earlier, and both sexes mated earlier as age increased. Duration of m ating also was influenced by age of either sex, but these differences were small relative to the mean total duration of mating. Differences in female age seldom resulted in large differences in occurrence of ma ting on mating stations, but when differences occurred, younger female s were more often mated than older females. Changes in temporal patter ns of sexual response and receptivity of males and females, respective ly, probably caused the observed effects of age on mating occurrence.