HOW HOST AND HABITAT FACTORS AFFECT PARASITE INFECTION WITHIN LARVAL ODONATES: Travis McDevitt–Galles and Pieter T. J. Johnson University of Colorado: Boulder Dept. of Ecology and Evolutionary Biology TESTING THE ROLES OF HOST DENSITY, SPECIES IDENTITY, AND TRANSMISSION SUCCESS

Freshwater arthropod community

Importance of Parasites in community

Preston et al. 2013

Complexity of parasite infection patterns Internal parasites can be effect by two drastically different habitats The Host The Host’s environment What level drives patterns of infection Host effect? Habitat effects? Any potential interactions between the two Johnson et al. 2015

Complexity of parasite infection patterns Internal parasites can be effect by two drastically different habitats The Host The Host’s environment What level drives patterns of infection Host effect? Habitat effects? Any potential interactions between the two Johnson et al. 2015

Haematoloechus sp. life cycle Image Credit : Dr. Matthew Bolek

host habitat fish presence water chemistry 2 axis of PCA host density Snail density length : individual level foraging strategy development time suborder Interaction between fish and and suborder identity

Research goals Model patterns of the parasite Haematoloechus sp. in Odonate taxa What drives infection patterns, Host characteristic or habitat characteristics Are these effects constant across different taxa

Data structure 2 Years – 2014, Sites 3 Families 13 Genera 1600 Individuals : Infection status (1/0) and infection load (count)

host habitat fish presence water chemistry 2 axis of PCA host density Snail density length : individual level foraging strategy development time suborder Interaction between fish and and suborder identity

host habitat fish presence water chemistry 2 axis of PCA host density Snail density length : individual level foraging strategy development time suborder Interaction between fish and and suborder identity

Infection load modelInfection status model Hierarchical model structure

To determine relative importance of host vs habitat characteristics Calculate Intraclass correlation coefficient ( ICC ) Intraclass Correlation Coefficient Metric to determine how much variation is explained by grouping effect random intercepts (Habitat ID and Host taxa) Host traits vs. habitat characteristics

Results Site Level ICC 0.21

Results Site Level ICC 0.21

Results Host Level ICC 0.10

Host versus Habitat ICC : 0.21ICC : 0.10 Infection Prevalence Infection Load ICC : 0.08 Infection Load ICC : 0.03

Research goals Model patterns of the parasite Haematoloechus sp. in Odonate taxa What drives infection patterns, Host characteristic or habitat characteristics Are these effects constant across different taxa

Final model Infection status Fixed EffectEstimated CoefficientZ valueP - Value Scaled centered body length0.60 ± < *** Fish presence-3.11 ± * Scaled host density0.53 ± * Scaled water chemistry PCA ± * Scaled water chemistry PCA ± * Host suborder: Zygoptera-3.11 ± < *** Host suborder Zygoptera : fish presence4.93 ± < ***

Final model Infection status Fixed EffectEstimated CoefficientZ valueP - Value Scaled centered body length0.60 ± < *** Fish presence-3.11 ± * Scaled host density0.53 ± * Scaled water chemistry PCA ± * Scaled water chemistry PCA ± * Host suborder: Zygoptera-3.11 ± < *** Host suborder Zygoptera : fish presence4.93 ± < ***

Final model Infection status Fixed EffectEstimated CoefficientZ valueP - Value Scaled centered body length0.60 ± < *** Fish presence-3.11 ± * Scaled host density0.53 ± * Scaled water chemistry PCA ± * Scaled water chemistry PCA ± * Host suborder: Zygoptera-3.11 ± < *** Host suborder Zygoptera : fish presence4.93 ± < ***

Interaction between fish and host suborder Haematoloechus sp. prevalence Haematoloechus sp. load

Final model Infection load Fixed EffectEstimated CoefficientZ valueP - Value Scaled centered body length0.83 ± < *** Fish presence-0.91 ± Host suborder: Zygoptera-2.92 ± Host suborder Zygoptera : fish presence5.01 ± < ***

Final model Infection load Fixed EffectEstimated CoefficientZ valueP - Value Scaled centered body length0.83 ± < *** Fish presence-0.91 ± Host suborder: Zygoptera-2.92 ± Host suborder Zygoptera : fish presence5.01 ± < ***

Interaction between fish and host suborder Haematoloechus sp. prevalence Haematoloechus sp. load

Predator Host Population Structure Infection Prevalence Predator - host - parasite interactions

Host abundance Predator influence on host density Host density, per dipnet

Predation influence on size

Predator Host population structure Selectively consuming host Host behavior Infection prevalence Predator – parasite interactions

Predator Host population structure Selectively consuming host Infection prevalence Predator – parasite interactions Johnson et al. 2006

Haematoloechus sp. life cycle Image Credit : Dr. Matthew Bolek

Snyder and Janovy 2009 DragonflyDamselfly Hypothesis: Fish induced altered behavior leads to contrasting effects of infection prevalence between dragonflies and damselflies

Conclusions Majority of variation in infection patterns is at the site level It is more important to know “where” you are than “who” you are Positive infection prevalence and load associated with Host Host body length Habitat Water chemistry score 1 and host density Interaction Between zygoptera and fish presence

Conclusions Majority of variation in infection patterns is at the site level It is more important to know “where” you are than “who” you are Positive infection prevalence and load associated with Host Host body length Habitat Water chemistry score 1 and host density Interaction Between zygoptera and fish presence

Acknowledgement Field Team Aaron Klingborg Megan Housman Keegan McCaffrery Nate Bowman Isaiah Hoyer Dina Sower Evan Esfahani Neal Handloser Mary-Jade Farruggia Isabel Jones Johnson Lab: Dana Calhoun Dr. Will Stutz Dr. Sarah Haas Max Joseph Katherine Richgels Dan Preston Joe Mihaljevic Meg Summerside Kelly Loria Funding: National Science Foundation University of Colorado: Boulder