# From Galls to Cecidological Herbaria: The Role of Gall Collections in Modern Life Sciences

## TL;DR

This paper reviews gall collections in European museums and highlights their potential for studying biodiversity and taxonomy.

## Contribution

The paper emphasizes the importance of cecidological collections for biodiversity research and advocates for their conservation and digitization.

## Key findings

- Gall collections can help track biodiversity changes over time.
- Well-preserved gall collections are valuable for taxonomy and systematics research.
- Digitizing gall specimens can improve data accessibility for scientists.

## Abstract

Galls (also known as cecidia) have been studied by botanists, zoologists and microbiologists over the last century. Indeed, galls can be induced by different animals, bacteria, viruses and fungi, so that their presence simultaneously attested the presence of specific host plants and gall-inducing species. Consequently, gall collections, also known as cecidological herbaria or cecidological collections, can be interesting to study biodiversity changes over time. This review describes the main cecidological collections currently available in different European museums in order to stimulate their future study. The present analysis suggests that well-organized and preserved cecidological collections have great potential to guide research in taxonomy and systematics. Furthermore, this review aims to encourage future research on the conservation and digitisation standards of gall specimens in order to make cecidological data more accessible to researchers.