Department

Biology

Program

Master's of Science (MSc.)

Year

Year 2

Supervisor Name

Keith Hobson

Supervisor Email

khobson6@uwo.ca

Abstract Text

Using stable isotope measurements of insect tissues to determine origin and migratory patterns is well established. However, isotopically determining nutritional origins of lipids, the primary fuel of migration, has not been as thoroughly researched. We explored isotopic links between diet and stored lipids in laboratory raised True armyworm moths (Mythimna unipuncta) using δ13C and δ2H measurements. Pupae were randomly separated into four groups (n=20) and fed isotopically distinct nectar, each consisting of a combination of high δ13C (C4 sugar), or low δ13C (C3 sugar) carbohydrate, with high δ2H (deuterium spiked), or low δ2H (tap) water. After 6 days of feeding, lipids were extracted for isotopic analysis using CF-IRMS. The carbohydrate contributed to approximately 80% of the δ13C and water contributed to approximately 13% of the δ2H in lipids. Lipids from C4 fed moths had higher δ13C values compared to C3 fed moths (-29.1 vs -16.6 ‰, P2H values compared to moths given tap water (-187.3 vs -254.6 ‰, P13C which can be used to provide continental isoscapes for tracking sources of stored lipids.

Study completed

Dietary Restrictions

Fish

Creative Commons License

Creative Commons Attribution 3.0 License
This work is licensed under a Creative Commons Attribution 3.0 License.

Share

COinS
 

Tracing nutrient sources to lipid production in insects using stable isotope (δ13C, δ2H) tracers: Implications for nutritional physiology of migratory species.

Using stable isotope measurements of insect tissues to determine origin and migratory patterns is well established. However, isotopically determining nutritional origins of lipids, the primary fuel of migration, has not been as thoroughly researched. We explored isotopic links between diet and stored lipids in laboratory raised True armyworm moths (Mythimna unipuncta) using δ13C and δ2H measurements. Pupae were randomly separated into four groups (n=20) and fed isotopically distinct nectar, each consisting of a combination of high δ13C (C4 sugar), or low δ13C (C3 sugar) carbohydrate, with high δ2H (deuterium spiked), or low δ2H (tap) water. After 6 days of feeding, lipids were extracted for isotopic analysis using CF-IRMS. The carbohydrate contributed to approximately 80% of the δ13C and water contributed to approximately 13% of the δ2H in lipids. Lipids from C4 fed moths had higher δ13C values compared to C3 fed moths (-29.1 vs -16.6 ‰, P2H values compared to moths given tap water (-187.3 vs -254.6 ‰, P13C which can be used to provide continental isoscapes for tracking sources of stored lipids.