Carcass scavenging relaxes chemical-driven female interference competition in flour beetles

<p>Female-female nonsexual interference competition is a major fitness determinant of biased sex-ratio groups with high female density. <span>What strategies can females use to overcome the negative impact of this competition? </span><span>We used flour beetle <i>Tribolium castaneum</i> </span>to answer this question, where competing females <span>from female-biased groups were already known to suppress each other's fecundity by secreting toxic quinones from their stink glands, indicating a unique chemical-driven interference competition. Surprisingly, </span><span>increasing resources</span><span> did not alleviate these fitness costs. Females also did not </span>disperse more from the site of interference competition. Hence, the <span>competition was neither influenced by the total resource availability nor the lack of opportunity to </span>avoid chemical interference<span>. Instead, protein sequestered via scavenging of nutrient-rich carcasses relaxed female competition, by increasing their fecundity and reducing the quinone content. Finally, stink gland components themselves triggered carcass-scavenging and increased fecundity, indicating the possibility of a novel chemical-driven feedback loop</span> to reduce the competition. Taken together, in the present work, we could provide the rare analyses where multiple competing hypotheses were jointly tested to establish carcass-scavenging as an important potential strategy to overcome the fitness costs of intrasexual female interference competition.</p>