Exploring the Speciation of Tahitian Plant Bugs

- 4 mins

University of California, Berkeley. Summer 2012


Background

While humans are equipped with the intelligence to make sophisticated machines and travel into space, insects really rule the world. With an estimated 10 million species and more biomass than humans, insects are the most successful creatures on Earth. While the reason for their success remains an important subject of scientific research, there is still an enormous gap in our understanding of insect taxonomy (the identification and description of species and other taxa). Insects in the family Miridae are known as plant bugs, and are part of a large group of insects called “true bugs” (suborder Heteroptera) that feed by sucking plant (and sometimes animal) juices through their mouth, a straw-like tube. Plant bugs represent the largest Heteropteran family with over 11,000 described species in about 1,400 genera (Wheeler, 2001). While the oldest Homo sapiens fossils date back to about 195,000 years ago (McDougall et al., 2005), plant bugs have roamed the Earth since the Jurassic period 199-145 million years ago (Wheeler, 2001). This study focuses on a group of plant bugs in the genus Pseudoloxops, which are diverse, understudied and endemic to the island of Tahiti, French Polynesia. Tahiti is a 403 mi2 volcanic island located in the Archipelago of the Society Islands in the southern Pacific Ocean, and harbors more endemic (i.e. found nowhere else) insect species than any other island in French Polynesia. Five species of Pseudoloxops were previously known from Tahiti (Knight, 1937), and were described based on morphological data alone, especially color patterns. Here we take an integrative taxonomic approach by combining morphological, molecular and ecological data as lines of evidence to delimit species (Gebiola et al., 2011). We use molecular genetic data as our primary line of evidence, and follow the genealogical species concept, which groups organisms into species based on their common ancestry (Shaw, 2001). The main goal of this project is to find out how many species of Pseudoloxops there are on the island of Tahiti.

Methods

Results and Discussion

We successfully amplified 17 of 18 specimens for each gene; 135 of 814 (16.6%) base pairs for CO1 were variable; 18 of 637 (2.8%) base pairs were variable for 28S. Gene sequences that were not amplified were coded as missing data. The phylogeny showed 5 distinct, well-supported monophyletic groups that we propose correspond to 5 species. (figure below)

Libère Jensen Ndacayisaba

Libère Jensen Ndacayisaba

Computational Biologist II at NextRNA Therapeutics

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