Extreme variation in testes size in an insect is linked to recent mating activity. (16th December 2019)

• Record Type: Journal Article
• Authors: Greenway, E. V(Ginny); Cirino, Lauren A.; Wilner, Daniela; Somjee, Ummat; Anagnostou, Maria‐Eleni; Hepple, Russell T.; Miller, Christine W.
• Is Part Of: Journal of evolutionary biology. Volume 33:Number 2(2020)
• Page Start: 142
• Page End: 150
• Publication Date: 2019-12-16
• Subjects: fertility -- insect reproduction -- mate choice -- metabolic costs -- sperm depletion -- strategic allocation; Evolution (Biology) -- Periodicals; Biology -- Periodicals; 576.8
• DOI: 10.1111/jeb.13574
• Languages: English
• ISSNs: 1010-061X

Abstract

Abstract: Ample sperm production is essential for successful male reproduction in many species. The amount of sperm a male can produce is typically constrained by the size of his testes, which can be energetically expensive to grow and maintain. Although the economics of ejaculate allocation has been the focus of much theoretical and empirical literature, relatively little attention has been paid to individual adult variation and plasticity at the source of sperm production, the testes themselves. We experimentally address this issue using the insect Narnia femorata Stål (Hemiptera: Coreidae). We established the metabolic cost of testicular tissue and then quantified variation in individual testes mass in response to multiple mate quality and quantity treatments . We uncovered extreme variation across individuals and considerable short‐term effects of mating activity on testes dry mass. Importantly, the observed variation in testes mass was associated with notable fitness consequences; females paired with males with larger testes had greater hatching success. Overall, pairing with a female resulted in a 11% reduction in dry testes mass. Despite this apparent considerable mating investment, we found no evidence of strategic allocation to higher quality females or longer‐term changes in testes mass. The dynamic nature of testes mass and its metabolic cost is vital to consider in the context of re‐mating rates, polyandry benefits and general mating system dynamics both in this species and more broadly. Abstract : Testes mass is central to sperm production ability in males of sexually reproducing species, yet varies considerably across individuals. In this study, we established the metabolic cost of testicular tissue, then quantified variation in individual testes mass in response to multiple mate quality and quantity treatments, in the insect Narnia femorata . We uncovered extreme variation and considerable short‐term effects of mating activity on testes dry mass, which in turn influenced partner reproductive success.