Eve Bruneau

1
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,
adult body size, female fecundity, 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
2003 Mentors Scott Wissinger Jason Jannot
Advisor Dallas Abbott
2
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)

3
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
4
Caddisfly Agrypnia deflata

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

5
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

6
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

7
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

8
Methods

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

9
Methods

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

10
Methods

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

11
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
12
Results
13
P 0.06
14
N 3
N 6
N 7
N 10
15
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

16
Conclusion

• Adult live weight
• shows sexual dimorphism
• not significantly different between treatments

17
Implications

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

18
Acknowledgements

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