Holte A E, Houck M A, Collie N L
Department of Biological Sciences, Texas Tech University, Lubbock 79409, USA.
Exp Appl Acarol. 2001;25(2):97-107. doi: 10.1023/a:1010655610575.
Phoresy is a symbiotic interaction that results in dispersal, benefiting the relocated organism without negatively impacting the phoretic host. It has long been considered that phoresy among astigmatid mites is somehow an intermediate precursor to the evolution of parasitism within the group. In astigmatid mites, only the heteromorphic deutonymph (hypopode) participates in phoretic dispersal, and the plesiomorphic hypopode may be the key to understanding the dynamics of the evolution of that parasitism. Hypopodes of Hemisarcoptes cooremani (Acari: Acariformes) and their phoretic beetle host Chilocorus cacti (Coleoptera: Coccinellidae) have become the experimental focus for studies concerned with the potential forces that influence the transition of a free-living life style into various coevolved relationships. Previous radiolabeling studies applied to H. cooremani and C. cacti determined that hypopodes of H. cooremani acquired resources from adults of C. cacti while in transit, negating the paradigm that the heteromorphy was purely phoretic. To further probe this relationship, we tested whether materials could be passed from the mites to their hosts. We report here a study using a tritium radiolabel, which indicated that beetles also acquire resources from the hypopodes. These results have implications for understanding the complex relationship between H. cooremani and C. cacti. We propose that this relationship should now correctly be defined as mutualistic (not phoretic) and develop a general model for the potential role of parasitism in the evolution of mutualism among the Astigmata.
携播是一种共生相互作用，其结果是实现传播，使被转移的生物受益，而不会对携播宿主产生负面影响。长期以来，人们一直认为粉螨科螨类之间的携播在某种程度上是该类群内寄生现象进化的中间前体。在粉螨科螨类中，只有异形的后若螨（蛰伏体）参与携播扩散，而原始的蛰伏体可能是理解该寄生现象进化动态的关键。科氏半疥螨（蜱螨亚纲：真螨目）的蛰伏体及其携播甲虫宿主仙人掌扁角叶甲（鞘翅目：瓢虫科）已成为研究关注的实验焦点，这些研究涉及影响从自由生活方式向各种协同进化关系转变的潜在因素。先前应用于科氏半疥螨和仙人掌扁角叶甲的放射性标记研究确定，科氏半疥螨的蛰伏体在转移过程中从仙人掌扁角叶甲成虫那里获取资源，这否定了异形纯粹是携播的范式。为了进一步探究这种关系，我们测试了物质是否可以从螨类传递到它们的宿主。我们在此报告一项使用氚放射性标记的研究，该研究表明甲虫也从蛰伏体获取资源。这些结果对于理解科氏半疥螨和仙人掌扁角叶甲之间的复杂关系具有启示意义。我们提出，这种关系现在应正确地定义为互利共生（而非携播），并为寄生现象在粉螨亚目互利共生进化中的潜在作用建立一个通用模型。
