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CARCASS SCAVENGING RELAXES THE CHEMICAL-DRIVEN FEMALE INTERFERENCE COMPETITION IN FLOUR BEETLES
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  • Basabi Bagchi,
  • Srijan Seal,
  • Manasven Raina,
  • Dipendra Basu,
  • imroze khan
Basabi Bagchi
Ashoka University
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Srijan Seal
Ashoka University
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Manasven Raina
Ashoka University
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Dipendra Basu
National Centre for Biological Sciences
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imroze khan
Ashoka University
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Abstract

Female-female nonsexual interference competition is rapidly emerging as a major fitness determinant of biased sex-ratio groups with high female density. How do females overcome such competition? We used adult flour beetle Tribolium castaneum to answer this question, where females from female-biased groups suppressed each other's fecundity by secreting toxic quinones from their stink glands, revealing a chemical-driven interference competition. The added natal resource did not alleviate these fitness costs. Females also did not disperse more at high female-density. Hence, the competition was neither limited by the total resource availability nor the inability to avoid chemical interference. Instead, protein sequestered via scavenging of nutrient-rich carcasses relaxed the female competition, by increasing their fecundity and reducing the quinone content. Even infected carcasses were scavenged to extract fitness benefits, despite the infection-risk. Finally, individual stink gland components triggered carcass-scavenging to increase fecundity, indicating a potentially novel chemical feedback loop to reduce the competition.