Eve Bruneau

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Effects of case removal and increased nutrition
on larval development, pupation, emergence time,
adult body size, female fecundity, and sexual
selection in a caddisfly (Agrypnia deflata, order
Trichoptera)
Effects of case removal and increased nutrition
on larval development, pupation, emergence time,
and sexual selection in a caddisfly (Agrypnia
deflata, order Trichoptera)

• Eve Bruneau
• Rocky Mountain Biological Laboratory
• Barnard College 2003
• Mentors Scott Wissinger Jason Jannot
• Advisor Dallas Abbott

Eve Bruneau Rocky
Mountain Biology Lab Barnard College
2004 Mentors Scott Wissinger Jason Jannot
Advisor Dallas Abbott
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Wetlands

• Unique ecosystems with specific plant and
  invertebrate species
• Terrestrial and aquatic invertebrates
• Invertebrates are primary consumers
• As primary consumers, they are important
  in understanding the entire aquatic ecosystem
  (Wissinger 1999)

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Aquatic Holometablous Insects

• Complex life cycle
• larva (aquatic)
• pupa (aquatic)
• adult (terrestrial)
• Some aquatic insects have non-feeding adults
• Example caddisflies

www.cedarcreek.umn.edu/insects/album/026008002.ap
.html
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Caddisfly Agrypnia deflata

• Order Trichoptera, family Phryganeidae
• Permanent ponds
• Case of silk and vegetation
• Larvae eat detritus
• Non-feeding adult
• Sexual dimorphism

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Goals

• To understand relationship between larval
  nutrition, development and adult body size,
  female fecundity, and mating systems by
  manipulating larval energy levels
• Increased energy- feeding protein Decreased
  energy - case removal

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Predictions

• Fed larvae will be larger than case removal
  individuals
• Case removal larvae will pupate and emerge later
  than fed individuals
• Case removal larvae will be smaller as adults
  than fed individuals

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Predictions

• Fed females will be choosier and choose fed males
  as mates over case removal males.
• Case removal females will either be less choosy
  or more choosy than fed females
• Fed males will out compete case removal males for
  matings
• Fed females will have a higher egg count than
  case removal females

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Methods

• 220 Agrypnia deflata
• 10 cages per treatment
• Fed treatment high protein
• Case removal treatment
• Measure Head Width Case Length

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Methods

• Pupate in sweater boxes
• Transfer to individual chambers
• Emerge and measure live weight

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Methods

• Mating Trials
• Female and 2 males of different treatments
• Behavior, latency to and length of copulation
• Mate selected

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Methods

• Female Fecundity
• Fertilized females in
• container to oviposit
• Eggs counted
• Adult Body Parts
• Measure body sections, organs, pupal case,
• exuvia

www.lambcom.net/krlt/Aquaticinsectsgallery.htm
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Results
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P 0.06
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Future Analysis

• Body part allocation
• Egg count

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Conclusions

• Development
• Time to pupation not significantly different
  between treatments
• fed individuals feed longer?
• handling stress high in both treatments?
• treatments conducted too late?
• Trend towards earlier fed individual emergence
• Treatment effects seen later in development

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Conclusion

• Adult live weight
• shows sexual dimorphism
• trend showing adult female case removal live
  weight decreases as total larval days increase

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Conclusions

• Mating trials
• No significant difference in latency to
  copulation or copulation length between
  treatments
• No apparent mate preference

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Implications

• Emergence time and mating system
• Larval Nutrition and adult body-part allocation
• Relationship between larval nutrition, adult
  mating system and reproductive success

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Acknowledgements

• Rocky Mountain Biological Lab,
• Jason Jannot, Scott Wissinger, Dallas
• Abbott, Hillary Callahan,
• Scott and Howards Cutthroats,
• Eric Bland, National Science Foundation