# Developmental plasticity enables an intestinal tapeworm to adapt to dietary stress

## TL;DR

This study shows how dietary fiber affects the development and survival of an intestinal worm, linking diet to the gut microbiome and host interactions.

## Contribution

The study reveals stage-dependent developmental plasticity in H. diminuta in response to dietary fiber.

## Key findings

- Fiber deprivation during colonization causes developmental arrest in H. diminuta.
- Adult worms show reversible suppression of reproduction under short-term fiber deprivation.
- Diet shapes the host's gut microbiota and metabolome, affecting helminth persistence.

## Abstract

Diet is one of the strongest ecological forces shaping the gut environment, yet its impact on intestinal worms (helminths) remains poorly understood. The helminth Hymenolepis diminuta is a suitable model for investigating how lifestyle changes in modern societies may disrupt host–helminth relationships. Here we show that dietary fiber availability shapes the developmental trajectory and life strategies of H. diminuta in a stage-dependent manner. Fiber deprivation at the time of host colonization leads to developmental arrest, manifested by reduced growth, absence of reproduction, and transcriptional changes consistent with suppressed development. This state is accompanied by diet-dependent remodeling of the host small intestinal microbiota and metabolome: whereas fiber-rich diets support fermentative microbial communities and a chemically diverse intestinal environment, the Western diet promotes dysbiotic profiles with reduced fermentation capacity and a more pro-inflammatory immune response. In contrast, adult H. diminuta that reach maturity in hosts maintained on a fiber-rich diet exhibit a reversible, estivation-like suppression of reproduction during short-term fiber deprivation, with full restoration of egg production following dietary recovery. Together, these findings indicate that dietary transitions associated with industrialized lifestyles can redirect helminth developmental programs and host–helminth–microbiome interactions, with implications for helminth persistence and potential therapeutic applications.

Here, the authors show that dietary fiber availability shapes the development and survival strategies of an intestinal worm, revealing stage-dependent plasticity and tight links between diet, the gut microbiome, host metabolism, and worm persistence.