How do land animals survive drought? by Joana Pereira da Silva

Francisca Antunes, Joana Silva e Rodrigo Monteiro

franciscaantunes286_ — 2025-05-21 13:25:19 UTC

We are Francisca Antunes, Joana Silva, and Rodrigo Monteiro, Environmental Science students at the University of Minho in Braga.

And we have a mutual dream... passing this class.

franciscaantunes286_ — 2025-05-21 13:26:47 UTC

Drought is a major threat to land animals, particularly those with permeable skin or limited movement. They depend on physiological and behavioral adaptations to retain water and prevent desiccation.

franciscaantunes286_ — 2025-05-21 13:27:01 UTC

Each species was tested in two cup setups - one open to airflow and one sealed - to compare responses to dry, windy conditions simulated by a fan. Resulting in behavioral changes and signs of desiccation to assess the impact of air exposure.

Discussion

franciscaantunes286_ — 2025-05-21 13:27:51 UTC

Overall, animals with protective external structures (shell or exoskeleton) retained more water while soft-bodied animals lost more confirming that morphological traits play a key role in desiccation resistance.

Aim of the study

joanapsilva — 2025-05-21 13:42:54 UTC

Explore how different terrestrial invertebrates respond to dry conditions by observing their resistance to water loss under controlled airflow.

Studied Animals

franciscaantunes286_ — 2025-05-21 13:50:22 UTC

Beetle, earthworm, slug and snail

Earthworm

franciscaantunes286_ — 2025-05-21 13:53:10 UTC

Soft-bodied animal.

Snail

franciscaantunes286_ — 2025-05-21 13:54:39 UTC

Has shell.

Slug

franciscaantunes286_ — 2025-05-21 13:56:52 UTC

Soft-bodied animal.

Beetle

joanapsilva — 2025-05-21 13:58:24 UTC

Has exoskeleton.

Weight variation per organism

rodrigomonteiro729_ — 2025-05-21 14:14:18 UTC

Beetles (cyan) and snails (pink) lost little weight — they're resistant to desiccation. Earthworms (green) and slugs (yellow) lost a lot — they're vulnerable due to soft, permeable bodies.

References

joanapsilva — 2025-05-21 14:15:56 UTC

Aquatic insects dealing with dehydration: do desiccation resistance traits differ in species with contrasting habitat preferences? (2016). Published on August 31, 2016.
Dehydration dynamics in terrestrial arthropods: from water sensing to trophic interactions.
How Terrestrial Animals Maintain Salt and Water Balance.
Mechanisms of Desiccation Tolerance: Themes and Variations in Brine Shrimp, Roundworms, and Tardigrades. (2020). Published on October 23, 2020.
OpenAI. (2023). ChatGPT (versão GPT-4) [Large language model]. Disponível em: https://chat.openai.com.
Sistema Excretor e Osmoregulacao – UFPA.
Apresenta detalhes sobre os mecanismos de osmoregulação em diversos animais, incluindo a excreção de diferentes compostos nitrogenados.
Disponível em: https://lobio.ufpa.br/AulasAnimaliaITeITIpdf/AnimaliaITi/Sistemaexcretoreosmoregulacao.pdf. Acesso em: 28 maio 2025.

Relationship Between Weight Variation and Initial Biomass in Organisms

rodrigomonteiro729_ — 2025-05-21 14:47:53 UTC

A fitted regression line (y = 1.71 * initial_biomass - 44.71) with a low R² value of 0.01 suggests a weak correlation, and a shaded confidence interval is included around the line.

Weight Variation by Initial Biomass in Terrestrial Organisms

rodrigomonteiro729_ — 2025-05-28 13:51:23 UTC

Once again the wheight variation is more noticeable in the slug and the earthworm and not so much in the beetle and the snail.