By: Rebecca Lancaster, Madilyn Robinson, and Savannah Ledo (Stonehill College, BIO323: Evolution, Spring 2025)
Overview
The Costus genus, commonly known as spiral gingers, is in the Costaceae family and is distinguished from other gingers by its unique spiraling leaves. Costus comprises over 80 species of perennial herbaceous plants native to Central and South America. Previous research demonstrates the Costus genus has independently evolved from the ancestral bee-pollination trait to hummingbird pollination multiple times. In The Convergent Evolution of Hummingbird Pollination Results in Repeated Floral Scent Loss Through Gene Downregulation, Dr. Kathy Darragh and her team examined over 30 Costus species’ floral scent compositions to understand how the species evolved from bee to hummingbird pollination. The study highlights the importance of selection, where certain traits are favored while others are lost to conserve energy costs. By comparing floral scent compounds, emission, and gene expression between bee-pollinated and hummingbird-pollinated Costus species, we gain a deeper understanding of the genetic factors driving floral scent evolution.