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Effects of sex, housing environment, and competitor presence on individual feeding behaviour in Trinidadian guppies

Nunes Madeira, Madalena (2025) BION03 20242
Degree Projects in Biology
Popular Abstract
Effects of sex, housing environment, and competitor presence on individual feeding behaviour in Trinidadian guppies

The availability of food in the environment is one of the most important factors, that influences how well a species performs but also influences its interactions with the surrounding ecosystem. Therefore, this is seen as a central driver of a species life-history.

For example, individuals that are exposed to environments with high food levels usually live a faster paced life, growing faster and reproducing earlier. While individuals from low food environments present a slower pace of life. This has been observed in different species, such as stream snails, rainbow trout and gobies.

Individual feeding behaviour has a... (More)
Effects of sex, housing environment, and competitor presence on individual feeding behaviour in Trinidadian guppies

The availability of food in the environment is one of the most important factors, that influences how well a species performs but also influences its interactions with the surrounding ecosystem. Therefore, this is seen as a central driver of a species life-history.

For example, individuals that are exposed to environments with high food levels usually live a faster paced life, growing faster and reproducing earlier. While individuals from low food environments present a slower pace of life. This has been observed in different species, such as stream snails, rainbow trout and gobies.

Individual feeding behaviour has a really important role in determining an individual’s ability to survive, find a mate and reproduce. This is a plastic trait, meaning that it can shift due to external environment (e.g., presence of a competitor or predation), but also due to the individuals own state. We can measure this behaviour by looking at feeding latency, rate and duration.

In this work we wanted to see what drives the variation in feeding behaviour in guppies (see illustration). For that, we conducted feeding trials with fish in individual tanks and fish in communal tanks. Each fish was trialled two times, one alone, and another one with a competitor present. During the 10-minute trial we observed how many times they took a bite of food, and later calculated feeding latency, duration and rate.

Results
Our results showed that males pecked at the food 50% less than females, spending less time feeding as well. This was in accordance with what we expected as several studies have highlighted that feeding is of more importance to females than to males, due to reproductive needs, and males have an overall smaller body size than females.

We also found that individually-housed fish pecked more than communally-housed fish when no competitor was present. This may be explained by the fact that fish in communal tanks were significantly smaller and lighter than those in individual tanks, suggesting that smaller individuals have a lower need for resources compared to larger ones.

When exposed to a competitor, individually housed fish decreased their pecking behaviour, while communally-housed fish showed no change. This supports our predictions, as communal fish are accustomed to competition, so the introduction of a competitor has little effect. In contrast, individually-housed fish, unaccustomed to competition, reduces pecking behaviour in response.

These results showed sex-specific effects on feeding behaviour, highlighting the importance of accounting for difference between males and females.

Master’s Degree Project in Biology 60 credits 2025
Department of Biology, Lund University

Advisor: Anja Felmy
Department of Biology (Less)
Please use this url to cite or link to this publication:
author
Nunes Madeira, Madalena
supervisor
organization
course
BION03 20242
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9212869
date added to LUP
2025-09-19 12:49:42
date last changed
2025-09-19 12:49:42
@misc{9212869,
  author       = {{Nunes Madeira, Madalena}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Effects of sex, housing environment, and competitor presence on individual feeding behaviour in Trinidadian guppies}},
  year         = {{2025}},
}