Emilia Santos NERC Independent Research Fellow and Assistant Professor:

As an evolutionary biologist, I study the origins and maintenance of Earth’s remarkable organismal diversity. My research focuses on understanding how organisms function and diversify into different species. I use Lake Malawi cichlid fishes as a model system –an extraordinary example of recent adaptive radiation, with over 700 species evolving in just the past million years. Despite their close evolutionary relationships, these species exhibit remarkable diversity in morphology, physiology, and behaviour.

My research group investigates how genetic variation drives morphological evolution in these fishes, with particular focus on a sexually selected trait: male egg-spots. These circular markings on male anal fins vary in number, size, and colour across approximately 1,500 cichlid species. Egg-spots function as ‘badges of status’ and are subject to sexual selection through both female choice and male-male competition. They play a vital role in the mating behaviour of mouth-brooding cichlids: during spawning, females collecting eggs in their mouths are attracted to the male’s egg-spots.

When females attempt to collect these spots, their mouths come close to the male’s genital opening, facilitating fertilization of the eggs within the female’s mouth, where she will incubate the developing offspring for several weeks. Through studying this fascinating trait, we aim to understand the evolutionary mechanisms driving egg-spot variation both within and between species.