The secret lives of mites & ticks unravelled

HYDERABAD

Mites and ticks are as diverse as they are mysterious. They may look like insects, but they actually belong to the broader category of ‘arachnids’ — creatures with two body segments and eight legs. From microscopic dust mites hiding in homes to blood‑sucking ticks clinging to pets or roaming forest floors, these organisms are omnipresent, occupying nearly every environment on Earth.

Some species are parasitic; others cause diseases such as scabies, lumpy skin disease, and plant galls, collectively leading to enormous global losses in livestock and agriculture. Scientists are now trying to predict their disease‑causing potential by studying their genomes.

A new genomic study led by Siddharth Kulkarni, a Ramanujan faculty member at the CSIR–Centre for Cellular and Molecular Biology (CCMB), Hyderabad, together with three undergraduate students from the Indian Institute of Science Education and Research (IISER), Thiruvananthapuram, offers crucial insights into the origins of parasitism and how these traits evolved over time — knowledge that could help strengthen disease‑control strategies in a changing climate.

The research disentangles a long‑standing evolutionary puzzle surrounding mites and ticks, revealing how parasitism emerged and diversified over more than 100 million years. The team examined 90 different arachnid genomes — the largest such dataset analysed so far — to trace signatures of their ancient evolutionary relationships.

The focus was on the physical arrangement of genes on chromosomes, whose shifts can be tracked like an evolutionary GPS. “Think of it like a deck of cards. Over millions of years, the cards (genes) get shuffled. But if you find two different groups of mites that have the exact same hand of cards in the same order, you know they share a common ancestor,” explained Dr. Kulkarni.

The analysis confirmed that mites and ticks fall into two distinct groups that originated independently from separate ancestors: Acariformes (which includes most mites) and Parasitiformes (which includes ticks and the remaining mites).

The finding is a significant step forward in reconstructing the evolutionary relationships among arachnids — from camel spiders to marine horseshoe crabs — whose lineage connections have long remained unclear. Mapping these relationships can help scientists predict the spread of known infections and identify potential new vectors before outbreaks occur, said Dr. Kulkarni.

Since mites and ticks move easily between wildlife, livestock, and humans, this knowledge can bolster early‑warning systems and guide targeted vector‑control efforts. As climate change and shifting land use reshape the global distribution of these tiny arachnids, understanding their interactions across ecosystems becomes crucial to safeguarding human, animal, and environmental health, said scientists, in a press release.