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Absence of reproductive organs increases somatic maintenance in the Hawk moth (Manduca sexta): A direct test of the disposable soma hypothesis
Author(s) -
Ojha Jaika,
Davidowitz Goggy
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.lb777
Subject(s) - manduca sexta , biology , myofibril , soma , endocrinology , reproduction , manduca , medicine , andrology , neuroscience , insect , ecology
Flight and reproduction are major resource sinks in flying organisms. The disposable soma hypothesis predicts that reducing reproduction allows more nutrients to be allocated for maintenance of somatic tissues, such as flight muscles. We tested this hypothesis by comparing the flight muscle structures of oophorectomized (ovaries removed) and orchiectomized (testes removed) individuals at different ages in Manduca sexta. Overall, oophorectomized and orchiectomized individuals have significantly greater number of mitochondria and percentage of area occupied by mitochondria compared to sham‐operated individuals. In addition, oophorectomized and orchiectomized individuals have significantly longer sarcomeres and larger size myofibrils compared to sham‐operated individuals. At day 7, oophorectomized and orchiectomized individuals exhibited smaller size mitochondria compared to sham‐operated individuals, suggesting a delay in mitochondrial degeneration. The levels of glycogen granules at different ages were also higher in oophorectomized and orchiectomized individuals compared to sham‐ operated individuals. These findings directly suggest that in the absence of reproductive organs, the increase in available energy is utilized for the maintenance of flight muscles, hence supporting the disposable soma hypothesis.