PRF: Assessing the Nestmate Relatedness and Sperm Precedence in a Communal Bee, Perdita portalis, Using DNA Fingerprnting

这项研究将涉及两个相互关联的项目，(1)计算估算亲缘关系，(2)评估一个群居的、在地面筑巢的蜜蜂（Perdita portalis）的精子优先程度。这两个目标可以最有效地实现使用DNA指纹的方法。估计配偶之间的平均亲缘关系是很有意义的，因为雌性门翅虫共同筑巢，每个巢穴有3到29只成年雌性。群居筑巢，即多个繁殖活跃的雌性共享一个巢，是一种进化稳定的社会互动形式，在蜜蜂中广泛存在，但很少受到社会进化学者的关注。虽然对于群居物种存在许多亲缘关系估计，但对于群居物种却很少有数据存在。所有的行为证据都表明，在门蝶中的筑巢伴侣是密切相关的，因为巢穴会被重复使用，而且不会飞的雄性会与雌性筑巢伴侣交配。为了理解亲缘选择和其他因素在形成社区社会中的作用，准确评估巢内亲缘关系是至关重要的。该项目的第二部分侧重于选择的因素，潜在的来源，维持二态雄性在门檀。这个物种的雄性有两种不重叠的形态：一种是大头，不能飞行的形态，另一种是小头，能飞行的形态。头大的雄鸟在产卵前立即与雌鸟交配，并进行雄性之间的战斗，通常会导致一方死亡。这些观察结果表明，大头虫的出现是精子优先权的结果，这赋予了雄性最后的交配优势。为了验证这一假设，有必要评估观察巢中产生的卵的父系关系。这两个项目的相关性在于雌性的社会行为对雄性的交配行为产生了选择压力，而巢内交配应该导致巢内亲缘关系水平的提高。

This research will involve two interrelated projects, (1) calculating nestmate relatedness and (2) assessing the extent of sperm precedence in a communal, ground-nesting bee, Perdita portalis. These two goals can be achieved most effectively using methods of DNA fingerprinting. Estimating average relatedness among nestmates is of interest because female P. portalis nest communally, with from 3 to 29 adult females per nest. Communal nesting, the sharing of a single nest by more than one reproductively active female, is an evolutionary stable form of social interaction which is widespread in bees, but which has received little attention by students of social evolution. While many relatedness estimates exist for eusocial species, few data exist for communal species. All behavioral evidence suggests that nestmates in P. portalis are closely related, both because nests are re-used for generations and because flightless males mate with their female nestmates. In order to understand the role of kin selection, and other factors, in shaping communal societies, it is essential to accurately assess within nest relatedness. Part two of the project focuses on the selective factors underlying the origin of maintenance of dimorphic males in P. portalis. Males in this species occur in two non- overlapping morphs: a large-headed, flightless morph and a small- headed, flight capable morph. Large-headed males mate with their female nestmates immediately prior to oviposition and engage in male-male battles which often lead to death of one combatant. These observations suggest that the large-headed morph has arisen as a result of sperm precedence that confers a last male mating advantage. In order to test this hypotheses it will be necessary to assess paternity of eggs produced in observation nests. The two projects are related in that the female social behavior establishes selective pressures on male mating behavior, and intra-nest mating should lead to elevated levels to nestmate relatedness.