家鸡对丝带凤蝶性二型体色的反应

Responses of domestic chicks(Gallus gallus domesticus)to the body color of sexual dimorphism in butterfly,Sericinus montelus

旨在明确丝带凤蝶成虫Sericinus montelus Gray在全光谱范围内存在性二型体色,评估鸟类对丝带凤蝶性二型体色的识别度,推测性二型体色是否对雌雄丝带凤蝶个体的生存概率产生影响。先用光谱检测仪测量丝带凤蝶雌雄成虫的反射光谱,分析反射光谱特征;再通过家鸡Gallus gallus domesticus视觉模型估算丝带凤蝶雌雄体色与预设背景的颜色差异。最后以小鸡为捕食者设计行为学试验,观测小鸡捕食雌雄丝带凤蝶成虫的行为反应。反射光谱测量结果显示雌雄丝带凤蝶在可见光和紫外波段都具有体色差异,雄性在前后翅白斑测量点上的亮度明显高于雌性。鸟类视觉模型结果表明,雄性丝带凤蝶所有测量点在明暗视觉(远距离)和颜色视觉(近距离)中的识别度值都高于识别阈值3,捕食者容易识别;但是雌性丝带凤蝶前翅和后翅黄白斑识别度值在明暗视觉和颜色视觉中都介于1与3之间,捕食者不易区分。捕食行为试验数据分析发现,捕食者发现猎物的潜伏时间及攻击潜伏时间没有显著差异,但小鸡啄食雄性猎物的次数及处理时间都显著高于雌性猎物。由此可见,与雌性丝带凤蝶相比,雄性在全光谱范围内的确具有更加亮丽的体色,但这种亮丽的视觉信号更易吸引鸟类捕食者的注意,带来了更高的捕食风险。

In the present study,we aim to determine the existence of sexual dimorphic body color in the whole spectrum,to evaluate the recognition of sexual dimorphic body color by birds,and to speculate whether the sexual dimorphic body color has an effect on the survival probability of male and female butterflies,Sericinus montelus Gray.We firstly used an Ocean Optic USB2000 spectrometer to measure the spectral reflectance and analyzed the characteristics of reflectance spectra of adult males and females in S.montelus.Then the domestic chicken Gallus Gallus domesticus visual model was used to estimate the differences between male and female coloration and the preset background.Finally,a behavioral experiment was designed with chicks as predators to observe the behavioral responses of chicks preying on adult male and female butterflies.The results of reflectance spectra showed that there were body color differences between male and female butterflies in both visible and UV bands,and the brightness of male butterflies was significantly higher than that of female butterflies in the measurement points of white spots on the forewing and hindwing.The results of the bird vision model showed that the recognition values of all measurement spots in in both achromatic contrasts(long distance)and chromatic vision(close distance)were higher than the recognition threshold of 3,and the predators were easy to recognize.However,the identification values of yellowish white markings of female forewing and hindwing were between 1 to 3 in chromatic and achromatic contrasts,which indicated low discriminability for avian predators.The analysis of predation experiment showed that there was no significant difference in the latency time of prey detection and attack latency time,but the number of pecks and handling time of chicks on male S.montelus significant higher than female prey.In conclusion,the male butterfly of S.montelus are more colorful than female in the whole spectrum range,but such bright visual signals are more likely to attract the attention of bird predators,which brings higher predation risk.