Relationship with fungi is one of the habitat adaptation of Sciaridae. While the earlier studies suggested that many fungus gnats are playing as the important vectors of various fungus diseases on plants and mushrooms, evidences have not been well reported. Based on a multi-gene phylogeny, by the Bayesian framework, we propose the correlation of four morphological characters of adults and habitat adaptation from saproxylic to phytophagous in the Sciaridae. Our results suggest that the evolution of habitat transition from dead plant litter to the live plant is related to habitat adaptation to the phytophagy and the morphological characters of fore tibia apex is also related to the functional linkage between these traits. We performed Bayes factor-based tests, referred with evolutionary pathway test (EPT), to decide the correlated traits gained the during evolutionary processes. The EPTs strongly suggest that fore tibia structures appeared first and followed by plant-feeding adaptation. The divergence time estimations of Sciaridae are also largely congruent with the fossil records. The members of subfamily Megalosphyinae have radiated explosively and contemporaneously since the Oligocene, with the expansion of modern grasslands and the increase of herbivores. Consequently, we suggest that the evolutionary benefit of tibial structure may be closely related with the fungal carrying in Sciaridae.

Recently, biological systematic studies have contributed for understanding of evolutionary histories of living organisms. In this talk, I present how evolutionary histories are inferred from the phylogenetic relationships. Two case studies in the Cimicomorpha (Heteroptera) are presented: 1. Inferring ancestral character states of the plant bugs (Heteroptera: Miridae); 2. Revealing evolutionary history of the Cimicoidea based on correlated evolution between habitat selection and morphological characters (Heteroptera: Cimiciformes). Case I: The first comprehensive cladistic analysis of Miridae, the plant bugs, is presented based on analysis of 3935 base pairs of mitochondrial (16S, COI) and nuclear (18S, 28SD3) DNA for 91 taxa in seven subfamilies. Data were analyzed using maximum likelihood (ML), parsimony, and Bayesian inference (BI) phylogenetic frameworks. Divergence time estimates indicate that the radiation of the Miridae began in the Permian; most genus-level radiations within subfamilies began in the late Cretaceous, probably in response to the angiosperm radiation. Ancestral feeding state reconstructions based on Bayesian and parsimony inference were largely congruent and both reconstructed phytophagy as the ancestral state of the Miridae. Furthermore, the feeding habits of the common ancestors of Mirinae + Deraeocorinae, Bryocorinae + Cylapinae + Isometopinae + Orthotylinae, and the remaining taxa excluding Phylinae, were inferred as phytophagous. Therefore, at least three shifts from phytophagy or polyphagy to predation occurred within the Miridae. Case II: The diverse habitat types and discrete morphological characters of cimicoid species provide a unique opportunity to study correlated evolution. Phylogenetic relationships within Cimicoidea were determined using Bayesian analyses of molecular data, allowing the generation of testable hypotheses of correlated evolution. An investigation of the correlation between habitat selection and morphological characters revealed that a dead plant habitat was correlated with the filiform antennal type. Furthermore, molecular dating analysis was used to examine divergence times within the Cimicoidea. Transitions to live plants from dead plants for most cimicoid clades started right after the mid–Cretaceous, coinciding with the radiation of the angiosperms. Using contingency analyses, I determined that evolutionary changes in morphological characters were dependent on habitat selection. Based on these results, I propose evolutionary historical hypotheses for the Cimicoidea.

Investigating the molecular clock, the ancestral character states, and the correlated evolution of discrete binary traits on phylogenetic trees, we studied the evolutionary history of the family Anthocoreidae, using ~3000bp of the mitochondrial 16S rRNA and nuclear 18S rRNA and 28S rRNA genes for 44 taxa. The BEAST and BayesTraits were used to examine the divergence times, cladogenesis, and historical habitat patterns. The correlated evolution of discrete characters was tested by reversible-jump Markov chain Monte Carlo. Our results suggest that (i) the ancestral habitat patterns of dead plants may have served as an important rule for the stem group of anthocorids; (ii) the radiation of angiosperms and the prey insect in the mid-Cretaceous might have provided anthocorids with more habitat options; and (iii) the transition of habitats played an important role for the change of ovipositor patterns in the family Anthocoreidae.