How Bacteria Help Birds Repel Parasites and Raise Their Young

Jenn Hoskins
11th May, 2024

How Bacteria Help Birds Repel Parasites and Raise Their Young

Image Source: Ray Bilcliff (photographer)

Key Findings

  • In Spain, researchers studied hoopoe birds to see how bacteria affect their smell and parasite attraction
  • They found that certain bacteria in the birds' nests and secretions can influence the types of odors produced
  • These odors can either attract or repel parasites, impacting the birds' susceptibility to infestation
Recent research conducted by the CSIC (Consejo Superior de Investigaciones Científicas) has shed new light on the complex interactions between animals, their microbial companions, and the parasites that afflict them[1]. This study focuses on the hoopoe bird (Upupa epops), investigating how the bacteria living with these birds might influence their susceptibility to parasites through the odors they produce. The hoopoe is known for its striking appearance and distinctive odor, which is partly produced by bacteria in its uropygial gland secretions. The gland secretes oils that the bird spreads over its feathers for maintenance and possibly as a defense against parasites. But what if the very bacteria that help produce these protective odors also inadvertently attract parasites? To explore this possibility, researchers first sterilized the nest materials of hoopoe nests using autoclaving, a process that uses high-pressure steam to kill all bacteria. By starting with a bacteria-free environment before the birds began reproduction, the team set the stage to observe how bacteria, odors, and parasites interact in a controlled setting. As the nestlings grew, the study monitored two types of parasites: chewing lice that infest adult female hoopoes and Carnus haemapterus flies that target nestlings. Alongside this, scientists characterized the microbial communities present in the nest environment and the volatile profiles—essentially, the odors—of both the nest materials and the cavity, as well as the uropygial secretions of the hoopoes. The findings of this study are significant because they help us understand the potential role of bacteria in the vulnerability of animals to parasitism. If certain bacteria are responsible for odors that attract parasites, this could have implications for how we manage wildlife and conserve species. The study also contributes to the broader understanding of how microbes influence animal communication and behavior, a field that has seen growing interest in recent years. Previous studies have highlighted the influence of microbial symbionts on the chemical profiles of their insect hosts, affecting behaviors such as mate attraction and social interactions[2]. The eco-evolutionary model developed in another study suggests that microbial products are often incorporated into animal communication systems, particularly when conveying identity rather than fitness or quality[3]. This idea is supported by research that points to the complexities of host-microbe interactions and the role of microbes in signal production among animals[4]. Furthermore, variations in microbial communities are known to affect social and communicative behavior in various species, including birds[5]. Building upon these earlier findings, the CSIC study offers a unique perspective by directly linking microbial communities to the vulnerability of a specific host to parasitism, a connection not previously explored in depth. By examining the hoopoe, a bird with a well-studied relationship with its symbiotic bacteria, the researchers could observe the direct effects of these bacteria on the birds' susceptibility to parasites. The study's methodology is noteworthy for its careful manipulation of the nest environment, allowing for a clear assessment of the role of bacteria. By sterilizing the nests, the researchers effectively reset the microbial landscape, providing a blank slate to observe how bacteria recolonize the environment and potentially influence the presence of parasites. This research opens the door for further investigation into the ways animals might regulate their microbial partners to balance the benefits of bacterial symbiosis with the risk of attracting parasites. It also raises questions about the evolution of such relationships and how they might be leveraged for conservation efforts. In conclusion, the CSIC study represents a significant advancement in our understanding of the interplay between animals, their microbial symbionts, and parasites. It underscores the importance of considering the role of microorganisms not only in the context of animal health and disease but also in broader ecological and evolutionary processes.

BiochemEcologyAnimal Science


Main Study

1) Volatiles of symbiotic bacterial origin explain ectoparasitism and fledging success of hoopoes

Published 10th May, 2024

Related Studies

2) Influence of microbial symbionts on insect pheromones.

3) The Extended Genotype: Microbially Mediated Olfactory Communication.

4) Microbes and animal olfactory communication: Where do we go from here?

5) Olfactory Communication via Microbiota: What Is Known in Birds?

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