Parasitic flowering plant collections embody the extended specimen

Abstract

The widespread digitization of natural history collections, combined with novel tools and approaches is revolutionizing biodiversity science. The ‘extended specimen’ concept advocates a more holistic approach in which a specimen is framed as a diverse stream of interconnected data. Herbarium specimens that by their very nature capture multispecies relationships, such as certain parasites, fungi and lichens, hold great potential to provide a broader and more integrative view of the ecology and evolution of symbiotic interactions. This particularly applies to parasite–host associations, which owing to their interconnectedness are especially vulnerable to global environmental change. Here, we present an overview of how parasitic flowering plants is represented in herbarium collections. We then discuss the variety of data that can be gathered from parasitic plant specimens, and how they can be used to understand global change impacts at multiple scales. Finally, we review best practices for sampling parasitic plants in the field, and subsequently preparing and digitizing these specimens. Plant parasitism has evolved 12 times within angiosperms, and similar to other plant taxa, herbarium collections represent the foundation for analysing key aspects of their ecology and evolution. Yet these collections hold far greater potential. Data and metadata obtained from parasitic plant specimens can inform analyses of co‐distribution patterns, changes in eco‐physiology and species plasticity spanning temporal and spatial scales, chemical ecology of tripartite interactions (e.g. host–parasite–herbivore), and molecular data critical for species conservation. Moreover, owing to the historic nature and sheer size of global herbarium collections, these data provide the spatiotemporal breadth essential for investigating organismal response to global change. Parasitic plant specimens are primed to serve as ideal examples of extended specimen concept and help motivate the next generation of creative and impactful collection‐based science. Continued digitization efforts and improved curatorial practices will contribute to opening these specimens to a broader audience, allowing integrative research spanning multiple domains and offering novel opportunities for education.

Leveraging natural history collections to understand the impacts of global change

“…They found that nests tended to be larger in colder climates and suggest that the ability to alter nest structure in response to climate change could influence species persistence. In Methods in Ecology and Evolution , Teixeira‐Costa et al (2023) review what is known about parasitic plant specimens in herbaria around the world. Impressively, there are upwards of 1,000,000 records (476,000 of which are georeferenced) of more than 4300 species.…”

Neglected plant parasites: Mitrastemonaceae

“…Thus, despite including a limited number of samples, our analysis corroborates the interpretation of Mitrastemonaceae as specific to hosts in the Fagaceae. Future analyses using methods such as DNA barcoding will be especially useful in cases where host identity is uncertain due to insufficient collection of host material (Pelser et al, 2016; Teixeira‐Costa et al, 2022). These methods are of increasing importance in the case of parasite species associated with the roots of their host plants, including not only Mitrastemonaceae but also euphytoid or obligate root parasites, for which careful examination and extensive excavation of roots are required for the correct host identification.…”

“…Allied to this peculiar lifestyle, the muted colors and small flower size ranging from 3 to 5 cm tall (Makino, 1911; Meijer & Veldkamp, 1993) make these plants easy to overlook among the leaf litter (Jochems, 1928). This may explain the small number of herbarium records (<150 specimens) available online for both M. matudae and M. yamamotoi in collections worldwide (Teixeira‐Costa et al, 2022). In turn, this scarcity of records could be why populations appear to be fragmented across the disjunct geographical distribution of the family (Figure 1e).…”

“…M. yamamotoi in collections worldwide (Teixeira-Costa et al, 2022). In turn, this scarcity of records could be why populations appear to be fragmented across the disjunct geographical distribution of the family (Figure 1e).…”

Herbarium collection of the Pontificia Universidad Católica de Valparaíso (PUCV), Chile

“…The next step would be the modernisation of the collection, taking advantage of modern technologies that allow inclusion of additional related information besides the preserved species following the extended specimen concept ( Lendemer et al 2019 ), which expands the possibilities of research and education that can be achieved with biological collections by including extra information that is usually lost after specimen preservation (e.g. tissue samples for DNA extraction, chemical profiles and ecological context information; Teixeira-Costa et al 2022 ).…”