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  • 1
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2020-03-27)
    Abstract: In herbivorous insects, the degree of host specialisation may be one ecological factor that shapes lifespan. Because host specialists can only exploit a limited number of plants, their lifecycle should be synchronised with host phenology to allow reproduction when suitable hosts are available. For species not undergoing diapause or dormancy, one strategy to achieve this could be evolving long lifespans. From a physiological perspective, oxidative stress could explain how lifespan is related to degree of host specialisation. Oxidative stress caused by Reactive Oxygen Species (ROS) might help underpin ageing (the Free Radical Theory of Aging (FRTA)) and mediate differences in lifespan. Here, we investigated how lifespan is shaped by the degree of host specialisation, phylogeny, oxidative damage accumulation and antioxidant protection in eight species of true fruit flies (Diptera: Tephritidae). We found that lifespan was not constrained by species relatedness or oxidative damage (arguing against the FRTA); nevertheless, average lifespan was positively associated with antioxidant protection. There was no lifespan difference between generalist and specialist species, but most of the tephritids studied had long lifespans in comparison with other dipterans. Long lifespan may be a trait under selection in fruit-feeding insects that do not use diapause.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2020
    detail.hit.zdb_id: 2615211-3
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  • 2
    In: Ecology and Evolution, Wiley, Vol. 7, No. 22 ( 2017-11), p. 9808-9817
    Abstract: In insects, lifespan and reproduction are strongly associated with nutrition. The ratio and amount of nutrients individuals consume affect their life expectancy and reproductive investment. The geometric framework ( GF ) enables us to explore how animals regulate their intake of multiple nutrients simultaneously and determine how these nutrients interact to affect life‐history traits of interest. Studies using the GF on host‐generalist tephritid flies have highlighted trade‐offs between longevity and reproductive effort in females, mediated by the protein‐to‐carbohydrate (P:C) ratio that individuals consume. Here, we tested how P and C intake affect lifespan ( LS ) in both sexes, and female lifetime ( LEP ), and daily ( DEP ) egg production, in Ceratitis cosyra , a host‐specialist tephritid fly. We then determined the P:C ratio that C. cosyra defends when offered a choice of foods. Female LS was optimized at a 0:1 P:C ratio, whereas to maximize their fecundity, females needed to consume a higher P:C ratio ( LEP = 1:6 P:C; DEP = 1:2.5 P:C). In males, LS was also optimized at a low P:C ratio of 1:10. However, when given the opportunity to regulate their intake, both sexes actively defended a 1:3 P:C ratio, which is closer to the target for DEP than either LS or LEP . Our results show that female C. cosyra experienced a moderate trade‐off between LS and fecundity. Moreover, the diets that maximized expression of LEP and DEP were of lower P:C ratio than those required for optimal expression of these traits in host‐generalist tephritids or other generalist insects.
    Type of Medium: Online Resource
    ISSN: 2045-7758 , 2045-7758
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 2635675-2
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  • 3
    Online Resource
    Online Resource
    Frontiers Media SA ; 2023
    In:  Frontiers in Insect Science Vol. 3 ( 2023-5-17)
    In: Frontiers in Insect Science, Frontiers Media SA, Vol. 3 ( 2023-5-17)
    Abstract: A changing environment can select on life-history traits and trade-offs in a myriad of ways. For example, global warming may shift phenology and thus the availability of host-plants. This may alter selection on survival and fertility schedules in herbivorous insects. If selection on life-histories changes, this may in turn select for altered nutrient intake, because the blend of nutrients organisms consume helps determine the expression of life-history traits. However, we lack empirical work testing whether shifts in the timing of oviposition alter nutrient intake and life-history strategies. Methods We tested in the marula fruit fly, Ceratitis cosyra , how upward-selection on the age of female oviposition, in comparison with laboratory adapted control flies, affects the sex-specific relationship between protein and carbohydrate intake and life-history traits including lifespan, female lifetime egg production and daily egg production. We then determined the macronutrient ratio consumed when flies from each selection line and sex were allowed to self-regulate their intake. Results Lifespan, lifetime egg production and daily egg production were optimised at similar protein to carbohydrate (P:C) ratios in flies from both selection lines. Likewise, females and males of both lines actively defended similar nutrient intake ratios (control =1:3.6 P:C; upward-selected = 1:3.2 P:C). Discussion Our results are comparable to those in non-selected C. cosyra , where the optima for each trait and the self-selected protein to carbohydrate ratio observed were nearly identical. The nutrient blend that needs to be ingested for optimal expression of a given trait appeared to be well conserved across laboratory adapted and experimentally selected populations. These results suggest that in C. cosyra , nutritional requirements do not respond to a temporal change in oviposition substrate availability.
    Type of Medium: Online Resource
    ISSN: 2673-8600
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2023
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  • 4
    Online Resource
    Online Resource
    Frontiers Media SA ; 2022
    In:  Frontiers in Physiology Vol. 13 ( 2022-2-28)
    In: Frontiers in Physiology, Frontiers Media SA, Vol. 13 ( 2022-2-28)
    Abstract: The expression of life-history traits, such as lifespan or reproductive effort, is tightly correlated with the amount and blend of macronutrients that individuals consume. In a range of herbivorous insects, consuming high protein to carbohydrate ratios (P:C) decreases lifespan but increases female fecundity. In other words, females face a resource-based trade-off between lifespan and fecundity. Redox metabolism may help mediate this trade-off, if oxidative damage is elevated by reproductive investment and if this damage, in turn, reduces lifespan. Here, we test how diets varying in P:C ratio affect oxidative damage and antioxidant protection in female and male of the marula fly, Ceratitis cosyra (Diptera: Tephritidae). We use replicated lines that have been subjected to experimental evolution and differ in their lifespan and reproductive scheduling. We predicted that high fecundity would be associated with high oxidative damage and reduced antioxidant defences, while longer lived flies would show reduced damage and elevated antioxidant defences. However, higher levels of oxidative damage were observed in long-lived control lines than selection lines, but only when fed the diet promoting lifespan. Flies fed diets promoting female fecundity (1:4 and 1:2 P:C) suffered greater oxidative damage to lipids than flies fed the best diet (0:1 P:C) for lifespan. Total antioxidant capacity was not affected by the selection regime or nutrition. Our results reiterate the importance of nutrition in affecting life-history traits, but suggest that in C. cosyra , reactive oxygen species play a minimal role in mediating dietary trade-offs between lifespan and reproduction.
    Type of Medium: Online Resource
    ISSN: 1664-042X
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2022
    detail.hit.zdb_id: 2564217-0
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  • 5
    In: Journal of Insect Physiology, Elsevier BV, Vol. 71 ( 2014-12), p. 78-86
    Type of Medium: Online Resource
    ISSN: 0022-1910
    RVK:
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2014
    detail.hit.zdb_id: 1482429-2
    SSG: 12
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