Physiological mechanisms of dehydration tolerance contribute to the invasion potential of Ceratitis capitata (Wiedemann) (Diptera : Tephritidae) relative to its less widely distributed congeners

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Authors

Weldon, Christopher William
Boardman, Leigh
Marlin, Danica
Terblanche, John S.

Journal Title

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Publisher

BioMed Central

Abstract

BACKGROUND : The Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) is a highly invasive species now with an almost cosmopolitan distribution. Two other damaging, polyphagous and closely-related species, the marula fruit fly, Ceratitis cosyra (Walker), and the Natal fly, Ceratitis rosa Karsch, are not established outside of sub-Saharan Africa. In this study, adult water balance traits and nutritional body composition were measured in all three species at different temperatures and levels of relative humidity to determine whether tolerance of water stress may partially explain their distribution. RESULTS : Adult C. capitata exhibited higher desiccation resistance than C. rosa but not C. cosyra. Desiccation resistance of C. capitata was associated with lower rates of water loss under hot and dry conditions, higher dehydration tolerance, and higher lipid reserves that were catabolised during water stress. In comparison with C. capitata, C. cosyra and C. rosa lost water at significantly higher rates under hot, dry conditions, and did not catabolise lipids or other sources of metabolic water during water stress. CONCLUSIONS : These results suggest that adult physiological traits permitting higher tolerance of water stress play a role in the success of C. capitata, particularly relative to C. rosa. The distribution of C. cosyra is likely determined by the interaction of temperature with water stress, as well as the availability of suitable hosts for larval development.

Description

Additional file 1: Table S1. Linear regression for the relationship between body mass (mg) and body water content (mg) for cohorts of three Ceratitis species that were subsequently tested for desiccation resistance and water loss rate at two temperatures. The equation for each relationship was used to estimate initial body water content from initial body mass for flies subjected to desiccation and water loss rate assays.
Additional file 2: Table S2. Analysis of deviance table for the final fitted parametric survival model that describes desiccation resistance of three Ceratitis species with respect to species, sex, temperature (Temp) and relative humidity (RH). Initial body mass was included as a covariate in the model. Data were fitted to a Weibull hazard function. Type III likelihood ratio tests were used to construct the analysis of deviance table. Significant effects (P < 0.05) are indicated by bold type.
Additional file 3: Table S3. General linear model for the relationship between species, sex, temperature (Temp) and relative humidity (RH) on the dehydration tolerance of three Ceratitis species. Estimated body water (determined from initial body mass using the equations in Table S1) was included as a covariate. Significant effects (P < 0.05) are indicated by bold type.
Additional file 4: Table S4. General linear model for the relationship between species, sex, temperature (Temp) and relative humidity (RH) on water loss rate of three Ceratitis species. Initial mass was included as a covariate. Significant effects (P < 0.05) are indicated by bold type.

Keywords

Desiccation resistance, Water loss, Dehydration tolerance, Starvation, Body composition

Sustainable Development Goals

Citation

Weldon, CW, Boardman, L, Marlin, D & Terblanche, JS 2016, 'Physiological mechanisms of dehydration tolerance contribute to the invasion potential of Ceratitis capitata (Wiedemann) (Diptera : Tephritidae) relative to its less widely distributed congeners', Frontiers in Zoology, vol. 13, art. no. 15, pp. 1-15.