-Meet My Mosquitofish-
Don’t judge a book by its cover! Although mosquitofish may not look particularly charismatic, they have some nifty quirks that make them a fascinating study species!
Unlike most fish who spawn, releasing eggs and sperm into the water for external fertilization and larval development, mosquitofish are viviparous, meaning the young develop inside the body. Male mosquitofish fertilize eggs inside the female using their gonopodium, a modified anal fin (think of this as a “fish penis”). This reproductive strategy generates sexual conflict– males seek to maximize their reproductive output by maximizing fertilizations, while females are limited in their reproductive output by their egg production and would thus benefit more from selective mate choice.
This conflict is echoed in the reproductive behavior of mosquitofish. Mosquitofish have a coercive mating system, where males court females only minimally and instead engage in sneak mating attempts, since females are rarely receptive to their advances. Harassment from males has been shown to decrease female feeding efficiency and is thus costly to females. Understanding the ecological and evolutionary consequences of these interactions is one of my goals for my graduate school research.
I am using mosquitofish as a model system to investigate some more general questions about ecology and evolutionary biology. These questions include:
How do intersexual interactions (interactions between males and females) impact ecological dynamics, particularly trophic dynamics?
Do females manipulate signals of fecundity to curtail the costly effects of male harassment?
How and why do local populations vary in their reproductive behaviors, and how do these differences affect local ecology?
Why You Should Care
Mosquitofish are voracious predators who consume the larvae of the most dangerous animal in the world– mosquitoes. Each year, mosquitoes are responsible for around one million deaths from diseases such as dengue, west nile virus, and malaria, and the recent spread of the Zika virus has reinvigorated interest in mosquito control. Mosquitofish have been introduced globally to reduce mosquito populations and have become the world’s most widespread freshwater fish. (They are found on every continent except Antarctica!) Unfortunately, some of these introductions have unintended negative consequences on native freshwater communities (for a full review of these impacts, see Pyke 2008). Understanding the ecology and behaviors of these fish can help us develop strategies that minimize the impact of mosquitofish introduction while maximizing mosquito control.