Fig 1.
Courtship sequence of the German cockroach.
The start and end time of each event was transcribed from video recordings, which were used to calculate latencies and durations of behaviors (denoted 1 to 5). Multiple wing-raising displays and nuptial feeding events may occur between the first and final steps in the sequence.
Fig 2.
Structure of the male tergal gland and experimental modifications.
The unaltered (A) and experimentally modified (B) tergal glands of the male German cockroach. Arrows indicate the slits and wells a female’s mouthparts would contact, located respectively on tergites 7 and 8 (A). Specialized cells secrete gland contents directly into these reservoirs. The wells on tergite 8 are most utilized by females during courtship; they were blocked by glue to determine how ablating this structure would affect mating success. In sham controls, glue was placed near but not covering the wells (B). Gland contents extracted from the reservoirs on tergite 8 were also used for later chemical analysis. Photographs were obtained using an Olympus Digital camera attached to an Olympus CX41 microscope (Olympus America, Center Valley, PA).
Fig 3.
Importance of the male tergal gland in mating success.
This experiment consisted of three treatments: males were either unaltered, glued near the tergal gland as a sham-control, or the tergal gland reservoirs on the eighth tergite were occluded with glue (n = 20 in each treatment group). The figure displays the percentage of males that mated. We utilized a Chi-square test with a post hoc Bonferroni correction to compare mating success.
Fig 4.
Contribution of the male tergal gland to female survival.
Sexually receptive females were given water only and paired with 2 males with intact, untreated tergal gland reservoirs (n = 29) or 2 males with their tergal gland reservoirs on the eighth tergite occluded with glue (n = 30). Males were phallomerectomized to prevent mating and replaced daily with fresh males of the same respective treatment. Female survival was monitored until all females died, and the treatments were compared with a two-sample t-test assuming unequal variances (Welch’s t-test).
Fig 5.
Effects of male nutritional condition on mating success.
Pairs that mated within an hour of first contact were considered successful; those that did not were considered a failure to mate. (A) Comparison of mating success of males fed either a nutritionally rich (complete) or nutritionally diluted (poor) diet. (B) Comparison of mating success of fed and starved males; these treatments were used in all subsequent analyses. A Chi-square test was used in both (A) and (B) to compare diet treatments.
Fig 6.
Effects of male nutritional condition on male precopulatory courtship behavior.
Three behaviors were examined. The first was the latency from the male’s first contact with the female to the male’s first wing-raising display (A). Latency to copulation is the time between first contact and successful copulation (B). Duration of copulation was from coupling to separation of the pair (C). For each assay, fed and starved males were compared using a two-sample t-test assuming equal variance.
Fig 7.
Effects of male nutritional condition on female nuptial feeding on the tergal gland secretion.
The first nuptial feeding event did not lead to a successful mating for any males (A). The last nuptial feeding event measures the duration of the final feeding event that was followed by a successful mating (B). For each assay, fed and starved males were compared using a two-sample t-test assuming equal variance.
Fig 8.
Effect of male nutritional condition on sugars in the nuptial secretion.
Maltose (A) and maltotriose (B), both major oligosaccharides in the tergal gland, were used to measure the effect of diet on the tergal gland secretion. Treatments were compared for each sugar using a Mann-Whitney U-test.