Tag: sexual selection

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How Female Fish Shape Evolution

By: Aisling Finnegan, Gracie Knudsen, & Angela Peri (Stonehill College, BIO323: Evolution, Spring 2026)

Even small choices in nature can have big effects over time. In Bahamas mosquitofish, the way females respond to males can influence who mates, and over time, can lead to the formation of new species. When talking about species in the context of this article, it is a group of organisms that can successfully mate and produce offspring. Speciation happens when populations of the same species become so different that they no long mate. This process often begins with behavioral isolation, which is when groups stop choosing each other as mates.

In the study we highlight here published in BMC Ecology and Evolution, Varpu Pärssinen and others examine if living in different environments could cause these kinds of behavioral changes. The researchers studied Bahamas mosquitofish, which are small freshwater fish that live in streams and ponds in the Bahamas. They observed populations that live in areas filled with predators and others that live in environments with a lack of predators. They notice that these differences in predation levels influence how the fish behave and live.

A short podcast summarizing the article. Image of Bahamas mosquitofish by Araújo et al. (2014): https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.1140
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The Evolution of Acoustic Signals in Poison Dart Frogs

By: Lia Casey, Jenna Cuzziere, and Rofail Wassef (Stonehill College, BIO 323: Evolution, Spring 2024)

Overview

Poison dart frogs, belonging to the Dendrobatidae family, are a fascinating group of amphibians renowned for their vibrant colors and potent toxins. These frogs are native to the tropical rainforests of Central and South America, where they inhabit diverse habitats ranging from leaf litter on the forest floor to the canopy of trees. Their striking hues, which include shades of red, blue, yellow, orange, and green, serve as a warning to potential predators of their toxic nature. Along with changing colors, poison dart frogs also can utilize acoustic signals (noises animals produce) to attract potential mates. Despite their small size, these frogs can produce a wide array of calls, ranging from simple chirps to complex series of notes. Male poison dart frogs often use their calls to establish and defend territories, as well as to attract mates during the breeding season. Each species has its unique call, which helps in species recognition and mate selection. Additionally, acoustic signals may also serve as a form of communication between males and females during courtship rituals, or mate selection, aiding in the coordination of reproductive behaviors. The frequency, duration, and intensity of these calls can convey information about the caller’s size, health, and vigor, influencing the outcome of mating interactions. Furthermore, studies have shown that environmental factors such as temperature and humidity can impact the acoustic properties of these calls, highlighting the intricate interplay between biology and the environment in the vocal behavior of poison dart frogs. Feel free to tune into the podcast to learn more about this exciting topic!

Short podcast summarizing the paper. Image of a Poison dart frog. Acoustic signals in poison dart frogs serve as vital communication tools for territorial defense, mate attraction, and courtship rituals within their diverse rainforest habitats. https://www.britannica.com/science/animal-communication/Signal-production
Podcast Music: https://www.youtube.com/watch?v=498HcLwcjxs
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The Benefits of Commitment in Black-headed Gulls

By: Karina Rodrigues, Joanna Soliman, Yenifer Oseguera, and Giana Youssef (Stonehill College, BIO323: Evolution, Spring 2023)

Overview

Loyalty, a quality some lack and some do not. Have you ever thought about the positive effects loyalty has on people, better yet species? In terms of evolution, loyalty translates to how committed a species is to its breeding partner. Originating from the Netherlands, black-headed gulls (Chroicocephalus ridibundus) were used to study the benefits of long-term relationships and if it plays a role in how parents invest more with their partners as well as their pair bond with one another. These seabirds were studied in a model environment that fits the birds natural needs in order to exhibit their natural behaviors. After testing different mechanisms, selection for mate retention reduces parental care conflicts between a pair and also sheds light to selecting traits that increase individuals fitness throughout evolution.

A short podcast summarizing the article.
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Sexual Selection: Big-brain vs. Small-brain

Gianna Amatucci, Nick Mulvey, Caitlin Welsh, & Cayleigh Shufelt (Stonehill College, BIO 323 Evolution, Fall 2019)

Predominantly residing in the tropics of South America, guppies are small and colorful freshwater fish. They are omnivorous animals, primarily consuming algae and brine shrimp. Unfortunately, guppies are preyed upon by a number of larger creatures, including birds, larger fish and mammals. While constantly having to avoid such predators, guppies are always in search of a suitable mate to spread their gene pools to future offspring. Alberto Corral-López and colleagues studied how predation pressure, in addition to cognitive ability and brain size, affected sexual behavior and sexual selection in guppies. The actions of both large-brained and small-brained female and male guppies were observed by Corral-López in order to study this phenomenon.

https://soundcloud.com/user-669960307/sexual-selection-big-brain-vs-small-brain/s-vmGa5
Domestic male guppy in an S-curve mating display. Image credit: “older guy 22feb08” by Alice Chaos is licensed under CC BY-NC-SA 2.0
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These Spiders Can Jump and Dance, but Can They Use Their Moves to Impress the Ladies?

By: Stefan Balestra, Adam Casey, Alessandro Puccio, and Walker Smith (Stonehill College, BIO323 Evolution, Spring 2018)

Spiders are considered by some as a source of fear, but many people find arachnids to be a cool group of arthropods. I mean, one of the most beloved superheroes is Spiderman, after all. Adding to the coolness factor associated with spiders, the spider discussed below is not only a jumping spider, but also a dancing spider with an interesting ritualized dance used to attract a mate. Additionally, the male individuals of the species exist in two morphs with different ritualized dances, competing in a spider dance battle of sorts to impress the ladies. Read on to learn more about the specific mode of sexual selection that contributes to the male morphs’ different looks and dance styles.

Listen now:

https://soundcloud.com/user-669960307/group-6/s-OKD82

Continue reading “These Spiders Can Jump and Dance, but Can They Use Their Moves to Impress the Ladies?”