Gilchrist George W, Rutowski Ronald L
Department of Zoology, Arizona State University, 85287, Tempe, AZ, USA.
Oecologia. 1986 Jan;68(2):235-240. doi: 10.1007/BF00384793.
A sex-limited color dimorphism occurs in many populations of Colias eurytheme. Alba females exhibit different patterns of resource allocation and are less attractive than orange females. This study examines some of the consequences of these differences in terms of reproductive success and population structure in a high density agricultural population.Alba females produced more eggs than orange females on a daily basis, but the morphs did not differ in three measures of size. Spermatophore counts revealed that fresh and worn females did not differ in mating frequency between the two morphs, but very worn alba females gained more matings than very worn orange females.In two mark-release-recapture experiments, alba females exhibited longer residence times than orange females. Changes in population structure over time suggest that this was due to dispersal of orange females from the mature field. Evidence is presented that orange females emigrate in response to male harassment at high density while alba females, exposed to less harassment, remain behind. We suggest that the persistence of the polymorphism in this agricultural population is at least partially facilitated by the cyclic cutting of the alfalfa.
在北美云粉蝶的许多种群中存在一种受性别限制的颜色二态性。白色雌性表现出不同的资源分配模式，并且不如橙色雌性有吸引力。本研究考察了在高密度农业种群中，这些差异在繁殖成功率和种群结构方面的一些后果。白色雌性每天产的卵比橙色雌性多，但两种形态在三个大小指标上并无差异。精包计数显示，新羽化和衰老的雌性在两种形态间的交配频率没有差异，但衰老程度很高的白色雌性比衰老程度很高的橙色雌性获得了更多交配机会。在两项标记重捕实验中，白色雌性比橙色雌性表现出更长的停留时间。种群结构随时间的变化表明，这是由于橙色雌性从成熟田地中扩散出去所致。有证据表明，橙色雌性在高密度时因受到雄性骚扰而迁出，而受到较少骚扰的白色雌性则留下来。我们认为，这种农业种群中多态性的持续存在至少部分得益于紫花苜蓿的周期性收割。
