Related Experiment Video
Updated: May 18, 2026
13:04
An Introduction to Parasitic Wasps of Drosophila and the Antiparasite Immune Response
Published on: May 7, 2012
Strong specificity in the interaction between parasitoids and symbiont-protected hosts
1Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland. romain.rouchet@eawag.ch
Journal of Evolutionary Biology
|September 25, 2012
Summary
Host-parasite interactions can maintain genetic diversity. This study found genotype-specific interactions between aphids and parasitoids, mediated by the endosymbiont Hamiltonella defensa, suggesting a key role for symbionts in coevolution.
Area of Science:
- Evolutionary Biology
- Ecology
- Genetics
Background:
- Coevolution between hosts and parasites can maintain genetic variation through negative frequency-dependence.
- Genotype-specific interactions are crucial for this process.
- Aphids (Aphis fabae) are often protected by endosymbionts like Hamiltonella defensa.
Purpose of the Study:
- To investigate genotype specificity in the interaction between parasitoids (Lysiphlebus fabarum) and aphid hosts (Aphis fabae).
- To determine if the endosymbiont Hamiltonella defensa mediates this specificity.
- To understand the role of symbionts in host-parasite coevolution.
Main Methods:
- Experimental evolution.
- Assessing host resistance and parasitoid infectivity.
- Analyzing aphid clone-by-parasitoid line interactions.
Main Results:
- Significant variation in aphid resistance and parasitoid infectivity was observed.
- A strong interaction between aphid clones and parasitoid lines affecting parasitism success was detected.
- This genotype specificity was found to be mediated by Hamiltonella defensa.
Conclusions:
- Endosymbionts like Hamiltonella defensa play a critical role in mediating genotype-specific host-parasite interactions.
- Symbiont-conferred resistance can drive coevolutionary dynamics and maintain genetic variation.
- The findings highlight the importance of considering endosymbionts in host-parasite coevolutionary studies.
Related Concept Videos
01:22Microbial Interactions: Parasitism
Parasitism is a form of microbial interaction in which parasitic microbes exploit a host organism for nutrients and shelter, often at the host's expense. Unlike mutualistic relationships, where both organisms benefit, parasitism benefits only the parasite and harms the host.Classification of ParasitesMicrobial parasites are broadly classified based on their location relative to the host.Ectoparasites remain on the host’s surface, such as the skin or outer tissues, drawing nutrients...
00:58Symbiosis
Symbiotic relationships are long-term, close interactions between individuals of different species that affect the distribution and abundance of those species. When a relationship is beneficial to both species, this is called mutualism. When the relationship is beneficial to one species but neither beneficial nor harmful to the other species, this is called commensalism. When one organism is harmed to benefit another, the relationship is known as parasitism. These types of relationships often...
01:21Frequency-dependent Selection
When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to as frequency-dependent selection. Frequency-dependent selection may occur between species or within a single species. This type of selection can either be positive—with more common phenotypes having higher fitness—or negative, with rarer phenotypes conferring increased fitness.
01:26Microbial Interactions: Cooperation
Microbial cooperation involves beneficial interactions in which different species work together for individual or mutual advantage. These interactions can profoundly influence ecological dynamics and evolutionary processes, and they are essential to many pathogenic and symbiotic relationships.Nematode–Bacteria CooperationA striking example is the relationship between the Gram-negative bacterium Xenorhabdus nematophila and the parasitic nematode Steinernema carpocapsae. Juvenile nematodes...
02:39Predator-Prey Interactions
Predators consume prey for energy. Predators that acquire prey and prey that avoid predation both increase their chances of survival and reproduction (i.e., fitness). Routine predator-prey interactions elicit mutual adaptations that improve predator offenses, such as claws, teeth, and speed, as well as prey defenses, including crypsis, aposematism, and mimicry. Thus, predator-prey interactions resemble an evolutionary arms race.
01:28Microbial Interactions: Predation
Microbial predation refers to the process by which one microorganism kills and consumes another to obtain nutrients and energy. It encompasses both bacterial and protozoan predators. This interaction plays a crucial role in shaping microbial communities and regulating nutrient cycling.Bacterial Predators: Epibiotic vs. EndobioticBacterial predators are classified based on their mode of attack as either epibiotic or endobiotic. Epibiotic predators, such as Vampirococcus, attach to the surface of...