Leschen Richard A B, Buckley Thomas R
New Zealand Arthropod Collection, Landcare Research, drivate Bag 92170, Auckland, New Zealand.
Syst Biol. 2007 Feb;56(1):97-112. doi: 10.1080/10635150701211844.
The dominance of angiosperms has played a direct role in the diversification of insects, especially Coleoptera. The shift to angiosperm feeding from other diets is likely to have increased the rate of speciation in Phytophaga. However, Phytophaga is only one of many hyperdiverse lineages of beetles and studies of host-shift proliferation have been somewhat limited to groups that primitively feed on plants. We have studied the diet-diverse beetle family Erotylidae (Cucujoidea) to determine if diet is correlated with high diversification rates and morphological evolution by first reconstructing ancestral diets and then testing for associations between diet and species number and diet and ovipositor type. A Bayesian phylogenetic analysis of morphological data that was previously published in Leschen (2003, Pages 1-108 in Fauna of New Zealand, 47; 53 terminal taxa and 1 outgroup, 120 adult characters and 1 diet character) yielded results that are similar to the parsimony analyses of Leschen (2003). Ancestral state reconstructions based on Bayesian and parsimony inference were largely congruent and both reconstructed microfungal feeding (the diet of the outgroup Biphyllidae) at the root of the Erotylidae tree. Shifts among microfungal, saprophagous, and phytophagous diets were most frequent. The largest numbers of species are contained in lineages that are macrofungal feeders (subfamily Erotylinae) and phytophagous (derived Languriinae), although the Bayesian posterior predictive tests of character state correlation were unable to detect any significant associations. Ovipositor morphology correlated with diet (i.e., acute forms were associated with phytophagy and unspecialized forms were associated with a mixture of diets). Although there is a general trend to increased species number associated with the shift from microfungal feeding to phytophagy (based on character mapping and mainly restricted to shifts in Languriinae), there is a large radiation of taxa feeding on macrofungi. Cycad feeding is scattered in more deeply diverged taxa and may have preceded the evolution of angiosperm feeding in some groups. Preliminary analysis of diet mapped onto higher beetle phylogenies suggests that about half of the major Coleoptera lineages may have had fungus-feeding ancestors. We discuss the roles of stochastic models and prior distributions of the reconstruction of ancestral character states in the context of the current data.
被子植物的优势在昆虫尤其是鞘翅目昆虫的多样化过程中发挥了直接作用。从其他食性转向以被子植物为食可能增加了植食亚目的物种形成速率。然而，植食亚目只是甲虫众多超多样谱系之一，而且宿主转移增殖的研究在某种程度上仅限于原始以植物为食的类群。我们研究了食性多样的拟步甲科（扁甲总科），通过首先重建祖先食性，然后测试食性与物种数量以及食性与产卵器类型之间的关联，来确定食性是否与高多样化速率和形态进化相关。对先前发表在莱申（2003年，《新西兰动物志》第47卷第1 - 108页；53个终端分类单元和1个外类群，120个成虫特征和1个食性特征）中的形态学数据进行贝叶斯系统发育分析，得到的结果与莱申（2003年）的简约分析结果相似。基于贝叶斯和简约推断的祖先状态重建在很大程度上是一致的，并且两者都在拟步甲科树的根部重建了以微真菌为食（外类群双叶甲科的食性）。在微真菌、腐食性和植食性食性之间的转变最为频繁。物种数量最多的类群包含在以大型真菌为食的谱系（拟步甲亚科）和植食性谱系（衍生的长扁甲亚科）中，尽管特征状态相关性的贝叶斯后验预测检验未能检测到任何显著关联。产卵器形态与食性相关（即尖锐形态与植食性相关，非特化形态与多种食性混合相关）。尽管从以微真菌为食向植食性转变存在物种数量增加的总体趋势（基于特征映射且主要限于长扁甲亚科的转变），但存在大量以大型真菌为食的类群辐射。苏铁食性分散在分化更深的类群中，并且在某些类群中可能早于被子植物食性的进化。对映射到更高阶甲虫系统发育树上的食性进行的初步分析表明，大约一半的主要鞘翅目谱系可能有以真菌为食的祖先。我们在当前数据的背景下讨论了随机模型和祖先特征状态重建的先验分布的作用。
