Miridae show remarkable diversity (>11,700 spp.), accounting for a quarter of all Heteroptera. However, their phylogeny and evolutional history is still remain unclear. In this work, we provide new suggestions for the phylogeny of Miridae using a larger dataset than previous studies. In addition, we suggest an alternative evolutionary history based on newly calibrated divergence dates for Miridae and its subordinate groups, and present probable factors of the family’s success in terms of species diversity. The entire dataset comprises 16 outgroups and 188 ingroup taxa including all seven known subfamilies and 37 out of 45 known tribes. Each species is aligned as 3,577 bp with six molecular loci (COI, 16S rRNA, 18S rRNA, 28S rRNA D3 region, H2A, and H3A).
Three species, Luciola unmunsana and L. papariensis, endemic to Korea and L. tsushimana, endemic to Japan, have been taxonomically controversial whether they are independent or a single species for a long time. Therefore, we examined genetic diversity and evolutionary history of these species as well as including the related congeners using COI gene sequences (DNA barcoding region). Interestingly, we found seven paraphyletic groups from three species: two paraphyletic groups from L. papariensis, three paraphyletic groups from L. unmunsana and two paraphyletic groups from L. tsushimana. Among them, the group III of L. unmunsana collected from Jeolla-do province has never been recognized in the previous studies. A molecular clock analysis indicated that the origin of the major lineages of L. unmunsana, L. papariensis and L. tsushimana occurred between ~5.62 to 3.16 Ma. The origin of the major lineages of the group II and III of L. unmunsana, the group II of L. papariensis and the three groups of L. tsushimana occurred in 3.49 Ma (4.45–2.51 Ma, 95% HPD), which is consistent with the final disconnection of Japan from Korean Peninsula. The subsequent divergences of these paraphyletic groups clearly showed they have undergone allopatric speciation associated with geologic events in Korea and the sea level changes between Korea and Japan.
Correlated evolution of biology and morphology of related organs of insects is an intriguing yet poorly understood topic. Gigantic member of phytophagan, the subfamily Cerambycinae provide us a unique opportunity to understand the topic because they have wide range of host plants, oviposition strategies and various forms of ovipositors. The evolutionary pathway of these traits is totally unknown because no robust internal phylogeny has been studied. Here we construct a multilocus phylogeny of Cerambycinae (134 taxa, 9 gene regions, 5211bp) focusing on wide range of oviposition strategies, host plant and ovipositor length. Ancestral state reconstruction analyses show that shortened ovipositor in Cerambycinae evolved at least four times independently; host plant use evolved from stressed hosts to dead and living host, broad leaved trees to conifer and herbaceus plants. Continuous mapping of ancestral state reconstruction shows extremely shortened ovipositor evolved independently at least four times. The correlated evolution test revealed the only correlation is between the ovipositor length and the oviposition strategy. This study unveiled the complex evolutionary history of ovipositor, oviposition strategy, host plant usage and their correlation within Cerambycinae for the first time.
Evolutionary relationship between ovipositior and oviposition behaviour in insect is an intriguing yet poorly understood topic. Gigantic member of phytophagan, the subfamily Cerambycinae provide us a unique opportunity to understand the topic because they have diversified but specialized host plants, oviposition strategies and ovipositors. The evolutionary pathway of these traits is totally unknown because no robust internal phylogeny of Cerambycinae has been studied. Here we construct a multi-locus phylogeny of Cerambycinae (134 taxa, 9 gene regions, 5211bp) focusing on wide range of oviposition site, host plant and ovipositor length. Ancestral state reconstruction analyses show some general trends in cerambycine evolution: i) host plant use evolved from stressed broad leaved trees to conifers and herbaceus plants; ii) oviposition site evolved from bark crevice to wood fissure or plant surface; iii) extremely shortened and elongated ovipositor independently evolved at least four times, respectively. Correlated evolution test show that ovipositor length and oviposition strategy evolved with very strong correlation, while any of other two traits did. This study unveils the complex evolutionary history of ovipositor, oviposition site, host plant use and their correlation within Cerambycinae for the first time.
Acetylcholinesterase (AChE) plays a pivotal role in the synaptic transmission in the cholinergic nervous system of most animals, including insects. Insects have two different ace (ace1 and ace2) loci that encode two distinct AChEs (AChE1 and AChE2), which were originated by duplication events long before the radiation of insects. However, little is known about when the ace duplication occurred and how each duplicated ace locus has evolved to retain the original functions. In this study, we conducted phylogenetic analysis for cholinesterase genes from all the lower animals with their genome sequenced together with all known arthropod ace1 and ace2, including those from a number of insects that were newly cloned. Among several independent duplications in lower animal lineages, one duplication event found in platyhelminthes appeared to be the direct origin of arthropod ace1 and ace2. Comparison of the evolutionary distance (d) of two aces from different insect groups relative to those from common ancestors revealed that ace1 has evolved with a significantly slower rate compared to ace2, suggesting that the ace1 lineage has maintained relatively more essential functions following duplication. When the dN/dS ratio was compared between ace1 and ace2 within different insect orders, ace2 was determined to have received relatively more positive selection pressure in Diptera and Hymenoptera whereas the same was true for ace1 in Coleoptera, Hemiptera and Lepidoptera. Along with the relatively more decreased d value for ace2, such an increased dN/dS ratio for ace2 in Diptera and Hymenoptera implied the incidence of functional transition of ace1 to ace2. Our findings should provide with new insights into the evolution of two insect AChEs: when they were generated and how they retain and gain the neuronal functions.
The Yongdong basin developed during Early Cretaceous in the central part of the Korean Peninsula and bounded on the northwest and southeast by northeast trending mega-scale strike-slip Yongdong Fault. An 8 km thick succession of exclusively terrigeneous sediments can be grouped into two mega-sequences. In concert with the migration of depocenter, the upper sequence overlaps the lower and occupies northern part of the basin during basin evolution. Alluvial and lacustrine environments were predominantly formed from early to late stage of the basin formation. Several lines of evidence support that the basin was formed within intra-arc tectonic environments and destroyed by polyphase tectonic force. Schematic evolutionary diagram of the basin is proposed.
Plants have evolved elaborate innate immune systems against invading pathogens, such as bacteria, fungi, oomycetes, viruses and insects. Among them, intracellular immune receptors known as nucleotide-binding site and leucine-rich repeat (NB-LRR) play critical roles in effector-triggered immunity (ETI) regarding to plant defense. Here, we identified potential NB-LRR coding sequences from pepper genome using bioinformatics analysis and performed comparative analysis with Solanaceae plants. As a result, we identified 267, 443, and 755 NBS-encoding genes in the genome of tomato, potato, and pepper, respectively. These may indicate that the Solanaceae NB-LRRs were evolved through species-specific unequal-duplication event. Further phylogenetic and clustering analyses revealed that Solanaceae NB-LRRs were classified into the 14 subgroups with 1 TNL and 13 CNL types. We found that the genes in CNL-G1 and CNL-G2 subgroup were highly expanded compared to other subgroup showing a large portion of NB-LRR in pepper genome. Among 755 NB-LRRs in pepper genome, 623 were physically mapped on all 12 pepper chromosome pseudomolecules. Furthermore, a number of NB-LRRs in the same group were physically clustered by tandem array in the specific chromosome. Genome-wide identification of pepper NB-LRR family and their evolutionary analysis could provide an important resource for identification and characterization of genes for breeding of disease resistance crops.