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Ben Sadd
Ben Sadd
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Research in host-parasite evolutionary ecology

Research in the group concerns the causes and consequences of genotypic and phenotypic diversity, with a focus on these issues in relation to host-parasite interactions and pollinator health. Principally, studies use bumblebee-parasite systems and decorated crickets. To answer questions within the realm of host-parasite Evolutionary Ecology and Ecological Immunology, we combine fieldwork, lab experiments, experimental infections, experimental evolution, and genetic, genomic, and transcriptomic approaches.

Although, interlinked, current research can be broken into the following main categories:

  1. Importance of l​ocal or global heterogeneity for immunity/infection
  2. Evolutionary ecology of trans-generational immunity
  3. Evolutionary and ecological perspective of gut microbiota as mediators of health
  4. Reproductive investment and immunity in the face of variable infection threats 

Importance of local or global ecological heterogeneity for immunity/infection outcomes

The world we live in is a very changeable one, with environments varying over both space and time. How host-parasite interactions are influenced by this variation will have important consequences for understanding diversity, host-parasite dynamics, and a number of linked phenomena.

~We ask how local variation in the ecology of individual hosts (conspecific interactions, nutrition, parasite experience, pesticides) influences investment into immunity, infection outcomes, and ultimately evolutionary fitness.~

~On a broader scale, we ask how ecological variation across a host's range, and host community composition impact the investment into and evolution of host defences against disease and the evolution of key parasite traits, such as virulence.~

Evolutionary ecology of trans-generational im​​munity 

Nested within the above section, there is a focus on insect trans-generational immunity. Under certain ecological conditions, there will be a benefit for mothers to adjust levels of offspring immunity contingent on their own parasite experience. This is seen for bumble bee antibacterial immunity. 

~We are looking closer at the mechanisms underlying this phenomenon in insects, and carrying out further experiments to place the costs and benefits of trans-generational immunity into an evolutionary ecology framework.~

​​Evolutionary and ecological perspective of gut microbiota as mediators of health​

It is increasingly apparent that microbial communities living on and within many organisms can have a profound impact on their health and evolutionary fitness. This includes interactions with the immune system and the determination of parasite infection outcomes. 

~We are investigating the specificity of these relationships, and how the immune system plays a role in mediating these critical relationships.~ 

Reproductive investment and immunity in the face of variable infection threats

There is a strong connection between infection and life history investment, such that infection status may lead to plastic adjustment of life history strategies, particularly reproduction. On top of this, further biotic and abiotic cues may modulate any changes in investment to reproduction and immunity.  

~We are investigating how life history strategies are influenced by interactions between infection, current status of an organism, and the external environment.~