Steyn Vernon M, Mitchell Katherine A, Terblanche John S
Centre for Invasion Biology, Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch, South Africa.
Centre for Invasion Biology, Department of Conservation Ecology and Entomology, Stellenbosch University, Stellenbosch, South Africa
Proc Biol Sci. 2016 Aug 17;283(1836). doi: 10.1098/rspb.2016.0905.
Enhanced dispersal ability may lead to accelerated range expansion and increased rates of population establishment, thereby affecting population genetic structure and evolutionary potential. Morphological, behavioural and physiological traits that characterize dispersive individuals from residents are poorly understood for many invertebrate systems, especially in non-polymorphic pterygote species. Here we examined phenotypic differences between dispersal-prone and philopatric individuals from repeated mark-release-recapture (MRR) experiments using an invasive agricultural pest, Ceratitis capitata Comprehensive morphometric assessment and subsequent minimal adequate modelling using an information theoretic approach identified thorax mass : body mass ratio as a key predictor of disperser flies under semi-natural conditions. Performance differences in flight ability were then examined under controlled laboratory conditions to assess whether greater thorax mass : body mass ratio was associated with enhanced flight ability. The larger thorax : body mass ratio was associated with measurable differences in mean flight duration, most predominantly in males, and also by their willingness to disperse, scored as the number and duration of voluntary flights. No other measures of whole-animal flight performance (e.g. mean and peak vertical force, total or maximum flight duration) differed. Variation in voluntary behaviour may result in significant alterations of movement behaviour and realized dispersal in nature. This phenomenon may help explain intraspecific variation in the dispersal ability of insects.
更强的扩散能力可能导致分布范围加速扩大和种群建立速率增加，从而影响种群遗传结构和进化潜力。对于许多无脊椎动物系统，尤其是非多态有翅昆虫物种而言，将具有扩散能力的个体与留居个体区分开来的形态、行为和生理特征还知之甚少。在此，我们利用一种入侵性农业害虫——地中海实蝇，通过重复标记-释放-重捕（MRR）实验，研究了易于扩散的个体和恋巢个体之间的表型差异。综合形态测量评估以及随后采用信息论方法进行的最小充分建模，确定胸质量与体重之比是半自然条件下扩散型果蝇的关键预测指标。随后在可控实验室条件下检测飞行能力的表现差异，以评估更大的胸质量与体重之比是否与增强的飞行能力相关。更大的胸与体重之比与平均飞行持续时间的可测量差异相关，在雄性中最为显著，并且还与它们的扩散意愿相关，扩散意愿通过自愿飞行的次数和持续时间来衡量。全动物飞行表现的其他指标（例如平均和峰值垂直力、总飞行持续时间或最大飞行持续时间）没有差异。自愿行为的变化可能导致自然环境中运动行为和实际扩散的显著改变。这种现象可能有助于解释昆虫扩散能力的种内变异。
