Figure 1.
Intraspecific morphological variation in Cyclommatus metallifer and condition dependent effects of high and low food availability.
(A) Intraspecific morphological variation in Cyclommatus metallifer. Large male (left), small male (center), and female (right) are shown. (B–D) Larval period duration, pupal weight and mandible length of stag beetle pupae reared under high and low nutritional regimes. (B) Males reared under high food conditions spent significantly more time as third instar larvae than males reared under low food conditions (P<0.001, student t-test). (C) Male stag beetles were significantly larger as pupae when reared under high food conditions (P<0.001, student t-test). (D) Adult mandible length was significantly longer in males reared under high food conditions (P<0.001, student t-test). The means ± SEs (N = 10) are shown.
Figure 2.
SEMs of the newly-formed stag beetle mandibles dissected from the prepupal cuticle immediately before pupation.
(A–C) SEMs of the left side of newly-formed stag beetle heads and mandibles. (A) Small male, (B) large male, (C) female. Mandibles are indicated in blue. (D–F) Magnified images of the mandibular regions indicated by the white boxes in A, B, and C. The surface structures of the mandibles are different among the three types of individuals.
Figure 3.
Effects of JHA treatment on male prepupae and larvae.
(A, B) The relationship between body weight (X-axis) and mandible length (Y-axis) of male pupae treated with acetone or JHA at the prepupal period and the larval period. (C) Pupal phenotype of a JHA treatment at the early half of the prepupal period which has abnormally exaggerated mandibles (right), compared with untreated individual of the same weight (left).
Figure 4.
Comparison of JH titer between large and small males during the early prepupal period.
(A) JH titer during the early prepupal period (mean ± SE). A significant difference in JH titer was found between large and small males. Numbers above each column denote the number of examined individuals. (B) The relationship between body weight and JH titer in males in the early prepupal period. The shaded circles represent the average value of the three measurements for a single individual with a standard error bar. Among individuals under high food conditions (i.e. large males), a significant positive correlation between weight and JH titer was found (P = 0.012, R2 = 0.55, Pearson correlation coefficient test). However, individuals reared under low food conditions (i.e. small males) showed no significant correlation between weight and hormone titer, possibly due to a much narrower range of body weights observed (P>0.1, R2 = 0.21, Pearson correlation test).