We conducted a field experiment with two common willow species, Salix cinerea and Salix fragilis. Branches were treated with mechanical damage or extracts from caterpillars and leaf beetles. We then measured volatile organic compound (VOC) emissions, leaf reflectance, and predation on artificial caterpillars. The two willow species used contrasting defence strategies. In S. fragilis, herbivore treatments triggered strong and specific VOC responses. These signals attracted more invertebrate predators, particularly when caterpillar cues were present. In contrast, S. cinerea showed weaker inducible responses. Here, bird predation correlated more with background chemical and visual traits than with induced signals. These results show that closely related plants can recruit different predator guilds. They also demonstrate that the ecological role of herbivore-induced plant volatiles depends on species-specific defence strategies.

Mezzomo P.,  Leong J. V.,  Vodrážka P., Moos M., Özcan E., Bina D., Ré Jorge L., Volfová T.,  Pokorný V., Volf M., (2026) Species-specific scents, targeted enemies: Volatile cues mediate predator attraction in willows. Functional Ecology, https://doi.org/10.1111/1365-2435.70289

We deployed more than 3,400 artificial caterpillars across six forest sites spanning a latitudinal gradient from 51°N to 34°S. Attack marks left by predators allowed us to quantify predation by birds, arthropods, and other predators. Contrary to common expectations, predation patterns differed strongly between forest strata. In tropical forests, caterpillars experienced higher predation in the understory, whereas in temperate forests predation was much stronger in the canopy. These patterns reflect shifts in the relative importance of different predator groups.
The study highlights how forest vertical structure shapes ecological interactions and demonstrates the value of coordinated global experiments using canopy crane facilities.

Sam K., Sivault E., Fernandez Garzon S., Finnie S., Kollross J., Houska Tahadlova M., Lenc J. Libra M., Ludwig A., Maraia H., Philip A. J., Re Jorge L., Xiao X & Volf M., (2026) Forest canopy insects are safer from predators in the tropics than at higher latitudes. Nature Communications, 2026, ttps://doi.org/10.1038/s41467-026-69935-7

More info about Rocky see here or here (orcid). ​

Visitors, high school students, had the unique opportunity to explore our workplace and learn about our research. The program included a live demonstration of plant defensive mechanisms, including observations under a stereomicroscope.
​ 
Abstract: How plants defend themselves against herbivores
For herbivores, plants are the main source of food. To survive, plants have developed a variety of defense strategies. Mechanical defenses include thorns or hairs, while chemical defenses involve toxic or bad-tasting substances. Some plants also release volatile compounds that can warn surrounding plants or attract natural enemies of herbivores.

link to the event :
www.bc.cas.cz/novinky/detail/7730-den-otevrenych-dveri-na-biologickem-centru-av-cr/  
​(in Czech)

Responsibilities
The successful candidate will:
·         Analyse Salicaceae metabolomes using advanced metabolomics and bioinformatics;
·        Develop bioinformatic pipelines integrating existing tools to acquire deeper insights into structural and functional chemical variation;
·         Collaborate with team members to interpret chemical diversity within an evolutionary and ecological framework, including the inference of Salicaceae phylogeny;
·       Contribute to joint analyses linking field-based ecological data with chemical and genomic datasets.

Through these approaches, the PhD candidate will contribute to understanding how plant chemistry evolves and adapts in response to environmental and ecological pressures, offering new insights into the multidimensional nature of phytochemical diversity.

Requirements

• A MSc degree (a non-negotiable requirement for PhD program eligibility);
• A strong interest in plant ecology, evolution, and bioinformatics;
• Experience with metabolomics or phylogenomics (highly desirable);
• Experience in bioinformatic data manipulation and workflow development (Bash essential, familiarity with Python or R highly desirable);
• Experience in biostatistics or data integration (advantageous);
• Fluent written and spoken English;
• Ability to work independently and collaboratively in a multidisciplinary environment.

What We Offer
The successful candidate will join the Laboratory of Evolutionary Ecology led by Martin Volf (https://www.volflab.com) at Biology Centre of the Czech Academy of Sciences, and will study at the University of South Bohemia in Ceske Budejovice, Czech Republic. Our young and dynamic team combines expertise in ecology, metabolomics, phylogenetics, and evolutionary biology. The department where we are based hosts a vibrant international research environment and is recognized as a world-class center for eco-evolutionary research. The PhD candidate will benefit from close collaboration with researchers conducting complementary fieldwork and experimental studies. The scholarship fully covers living expenses in the Czech Republic for the entire four-year PhD program.

Application Details

• Deadline: December 10, 2025

• Interviews: Mid-December 2025
• Start date: April 1, 2026

​To apply, please send:

1. A CV,
2. A cover letter describing your motivation, relevant experience, and research interests,
3. Contact details for three references

Applications and inquiries should be sent to volf@entu.cas.cz

By analysing leaf chemistry, we found that the hybrids typically exhibit intermediate levels of metabolite concentration and richness compared to their parental species. However, they stand out with higher structural α-diversity, suggesting greater within-individual chemical complexity. Interestingly, most hybrid-specific compounds were structurally close to those of the parent species, indicating subtle chemical modifications rather than radical shifts.
Although overall herbivory levels did not differ significantly among hybrids and parental species, herbivore responses varied depending on metabolite richness and structural diversity. Notably, soil nitrogen levels were linked to structural variation in metabolomes, with hybrids showing greater chemical variation along nitrogen gradients. These findings suggest that while hybridization alters chemical structure only moderately, the resulting diversity may provide adaptive flexibility to changing soil conditions, potentially contributing to the ecological success of these hybrids.



Renoult S.A. , Leong J.V., Mezzomo P., Sebek P., Koutecký P., Kukla J., Nguyen P., Moos M., Pokorny V.,  Wagner N.D., Frouz J., van Dam N.M.,  Volf M.,  (2025) Effects of hybridization on chemical diversity and plant-insect herbivore interactions in Salix alba × fragilis, Journal of Experimental Botany, eraf296, https://doi.org/10.1093/jxb/eraf296

Responsibilities include:

•   Preparing plant extracts from species with varying chemical profiles
• Rearing insect herbivores for feeding trials using diets infused with extracts or analytical standards
• Conducting fieldwork in Europe and overseas to collect additional plant samples
•  Analysing and interpreting the data and results
• Leading the preparation of manuscripts for publication

While the project has defined goals, we welcome candidates with initiative and interest in broadening its scope through independent hypothesis testing.
Required Qualifications and Skills:

• PhD in a relevant field (required for postdoctoral eligibility)
• Strong interest in chemical ecology, plant-insect interactions, or entomology
• Experience in both field and laboratory research
• Proficiency in insect rearing and basic analytical chemistry techniques
• Solid background in biostatistics
• Excellent written and spoken English

·         Ability to work both independently and collaboratively
About the Host Institution
The successful applicant will join the Laboratory of Evolutionary Ecology led by Dr. Martin Volf at the Institute of Entomology, Biology Center of the Czech Academy of Science (web). The candidate will live in Ceske Budejovice (Czech Republic) (web) where the laboratory experiments will take place and conduct fieldwork in Europe and overseas. Our department is a diverse, international team studying ecology, evolution and biogeography, and a world-class centre for interaction network research with regular publications in leading journals.
Position Details:
·         Application deadline: June 25, 2025
·         Interviews: early July 2025
·         Start date: November 1, 2025
·         Duration: August 31, 2027
·         The position is fully funded and includes a fellowship sufficient to cover living expenses in the Czech Republic.
·         Applicants from all countries are welcome to apply.
 
How to Apply
Please send the following to Dr. Martin Volf (volf@entu.cas.cz):
·         Your CV
·         A cover letter outlining your qualifications, relevant experience, and motivation
·         Contact information for three referees