Figure 1.

One of 15 replicate blocks within our experimental design. Stock virgins were single mated to produce four F1 families. Within each of these, two F1 siblings were mated to generate inbred F2 offspring, and two siblings were mated to beetles from other families to produce outcrossed F2 offspring. Shortly before emergence (day 26), F2 families were split: part of the pupae received a heat shock treatment (50 min on 50°C) while the remaining pupae were maintained at standard culturing conditions. Resulting F2 males were mated to females previously mated to irradiated males (not shown) to assess the effects of heat shock and inbreeding treatments on sperm-competitive ability. Dashed line indicates mating between nonadjacently depicted families. ○: females; □ males; ▪ heat-shocked males.