Table 2.
Effects of age and prior feeding history on the reflectance spectral traits of male C. umbratica. (Data are presented as mean±s.e. and are analysed by independent t-tests for age effects or paired t-tests for effects of prior feeding history. Boldfaced cells show statistically significant results. *Mann–Whitney U-test.)
| spectral variables | body part | age (see figure 2) | prior feeding history (see figure 3) | |||||
|---|---|---|---|---|---|---|---|---|
| young | old | statistics | comments | change | statistics | comments | ||
| UV intensity (%) | abdomen | 31.67±2.83; n=25 | 38.69±3.74; n=23 | t46=−1.511, p=0.138 | no difference | 10.79±2.17 | t9=−4.977, p<0.001 | satiated males are UV brighter |
| carapace | 32.44±3.42; n=24 | 25.86±3.17; n=22 | t44=1.405, p=0.167 | no difference | −0.74±1.56 | t9=0.472, p=0.648 | no change | |
| VIS intensity (%) | abdomen | 89.50±3.52; n=25 | 88.18±6.09; n=25 | t48=0.191, p=0.850 | no difference | 16.93±2.61 | t9=−6.486, p<0.001 | satiated males are VIS brighter |
| carapace | 64.38±3.29; n=25 | 53.20±3.23; n=25 | t48=2.451, p=0.018 | young males brighter | −1.14±1.75 | t9=0.650, p=0.532 | no change | |
| normalized total intensity | abdomen | 0.61±0.03; n=25 | 0.60±0.05; n=25 | t48=0.088, p=0.930 | no difference | 0.14±0.02 | t9=−6.717, p<0.001 | satiated males are brighter |
| carapace | 0.57±0.04; n=25 | 0.44±0.04; n=25 | t48=2.305, p=0.026 | young males brighter | 0.00±0.01 | t9=0.076, p=0.941 | no change | |
| UV peak (nm) | abdomen | 369.15±2.18; n=25 | 366.77±2.29; n=25 | t48=0.753, p=0.455 | no difference | −0.17±4.34 | t9=0.121, p=0.907 | no change |
| carapace | 376.62±1.64; n=25 | 370.57±1.46; n=25 | t48=2.765, p=0.008 | UV band shift towards shorter wavelengths in old males | −0.89±3.48 | t9=0.813, p=0.437 | no change | |
| VIS peak (nm) | abdomen | 584.20±2.89; n=25 | 579.23±3.24; n=25 | t48=1.144, p=0.258 | no difference | −3.38±8.82 | t9=1.211, p=0.257 | no change |
| carapace | 580.64±1.72; n=25 | 574.33±2.19; n=25 | Z50=−0.805, p=0.071* | no difference | −0.57±5.30 | t9=0.337, p=0.744 | no change | |
| band separation (nm) | abdomen | 215.05±1.57; n=25 | 212.46±1.75; n=25 | t48=1.133, p=0.263 | no difference | −3.21±9.33 | t9=1.088, p=0.305 | no change |
| carapace | 204.02±1.11; n=25 | 203.76±1.39; n=25 | t48=0.179, p=0.858 | no difference | 0.33±6.61 | t9=−0.158, p=0.878 | no change | |