Systematics of Eucharitidae (Hymenoptera: Chalcidoidea)

Eucharitidae 系统学（膜翅目：Chalcidoidea）

• 批准号: 0108245
• 负责人: John Heraty
• 金额: $ 9.38万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0108245&HistoricalAwards=false
• 关键词: Systematics; Eucharitidae; Hymenoptera; Chalcidoidea

Eucharitidae are one of the most diverse parasitic groups attacking eusocial insects. All eucharitid larvae are specialized parasites of ant pupae. Females deposit their eggs in plant tissue, and the active first-instar larvae are responsible for gaining transport to the ant nest. They are most common in tropical regions, but a few species occur as far north as Alaska and the Yukon. Initial results from a phylogenetic analysis of the 53 genera using 75 morphological features of adults indicate a strong correlation between the relationships of Eucharitidae and their ant hosts: 1) parasitism of Myrmicinae appears correlated with use of a thrips intermediate host to gain access to the ant brood, 2) parasitism of Ponerinae is correlated with independent larvae, and 3) parasitism of Formicinae is associated with the attraction of ants to the egg mass. Preliminary results from data collected for the D2 and D3 expansion regions of 28S rDNA show a strong correspondence with results from morphology-based analyses, but not without critical areas of conflict that need to be resolved. If strongly corroborated, molecular analyses will be used to reevaluate morphological character state coding and also to imply transformation series so that a more resolved hypothesis can be proposed for all genera based on morphology alone. Preliminary analyses suggest that Gollumiella and Akapala are key elements for establishing the polarity of behavioral changes in Eucharitidae, and emphasis will be made on obtaining new collections and biological information for these genera. If use of a thrips intermediate host is shown to be an ancestral mode for Oraseminae and Eucharitinae, this would suggest the behavior as primitive for the family and might indicate how the initial host shift to ants may have occurred. In Trigonalyoidea and Elasmus (Chalcidoidea), adaptation to parasitism of eusocial hosts may have been accomplished through a host shift from ancestors that were hyperparasitic in lepidopteran hosts to the hymenopteran predators of those Lepidoptera. If adaptation through a prey item to the predator is true for each of these groups, this general hypothesis could be applied to other parasitoids of eusocial insects.In natural or agricultural systems, Chalcidoidea are one of the most important groups controlling insect populations. With only about 20,000 of the estimated 400,000 thousand species named, and far fewer with known biology, this is a relatively unknown group. Eucharitidae are unusual within this assemblage because the genera and species are well known and they have a relatively conservative biology that corresponds with the initial analyses of relationships. As well, they show a high degree of geographic endemism that corresponds with the breakup of the southern continents approximately 40 to 70 million years ago. By providing a robust phylogenetic hypothesis using multiple methods (molecular, morphological and behavioral), we can better understand the mechanism of host shifts and the correlated increase in taxonomic diversity. A resolved phylogeny and understanding of behavioral evolution for Eucharitidae would form a model system for future comparative studies across the superfamily.

Eucharitidae 是攻击真社会性昆虫的最多样化的寄生群体之一。所有真蝽幼虫都是蚂蚁蛹的特化寄生虫。雌性将卵产在植物组织中，活跃的一龄幼虫负责运输到蚁巢。它们在热带地区最常见，但也有少数物种出现在阿拉斯加和育空地区的北部。使用成虫的 75 个形态特征对 53 个属进行系统发育分析的初步结果表明，Eucharitidae 与其蚂蚁宿主的关系之间存在很强的相关性：1）Myrmicinae 的寄生似乎与使用蓟马中间宿主获得蚂蚁巢穴相关，2）Ponerinae 的寄生与独立幼虫相关，3）Formicinae 的寄生 与蚂蚁对卵块的吸引力有关。 28S rDNA D2 和 D3 扩展区域收集的数据的初步结果显示与基于形态学的分析结果具有很强的一致性，但并非没有需要解决的关键冲突领域。如果得到强有力的证实，分子分析将用于重新评估形态特征状态编码，并暗示转化系列，以便可以仅基于形态为所有属提出更清晰的假设。初步分析表明，Gollumiella 和 Akapala 是确定 Eucharitidae 行为变化极性的关键因素，重点将放在获得这些属的新收集品和生物学信息上。如果使用蓟马中间宿主被证明是 Oraseminae 和 Eucharitinae 的祖先模式，这将表明该家族的行为是原始的，并且可能表明最初的宿主向蚂蚁的转变可能是如何发生的。在 Trigonalyoidea 和 Elasmus (Chalcidoidea) 中，对真社会宿主寄生的适应可能是通过从高度寄生于鳞翅目宿主的祖先到鳞翅目膜翅目捕食者的宿主转变来实现的。如果通过猎物对捕食者的适应对于这些群体中的每一个都是正确的，那么这个一般假设可以应用于真社会性昆虫的其他寄生蜂。在自然或农业系统中，Chalcidoidea是控制昆虫种群的最重要的群体之一。在估计的 4 亿个物种中，只有大约 20,000 个物种被命名，并且已知生物学的数量少得多，这是一个相对未知的群体。 Eucharitidae 在这个组合中是不寻常的，因为它们的属和种是众所周知的，而且它们具有相对保守的生物学特性，与最初的关系分析相对应。此外，它们还表现出高度的地理特有性，这与大约 40 至 7000 万年前南部大陆的分裂相对应。通过使用多种方法（分子、形态学和行为）提供可靠的系统发育假设，我们可以更好地理解宿主转移的机制以及分类多样性的相关增加。对 Eucharitidae 的系统发育和行为进化的理解将为未来跨总科的比较研究形成一个模型系统。