Nuptial food gifts influence female egg production in the scorpionfly Panorpa cognata

Abstract

. 1. Before copulation, male Panorpa cognata scorpionflies offer females a salivary secretion, which is consumed by the female during copulation. It has previously been demonstrated that this nuptial food gift functions as mating effort by increasing male attractiveness and by increasing ejaculate transfer during copulation.2. In this study, the effect of saliva consumption on female reproductive output was investigated, and thus the possibility that nuptial food gifts also serve as paternal investment. The experimental design enabled the effect of nuptial gift consumption to be disentangled from other possible effects of multiple mating or increased copula duration.3. The results showed that saliva consumption increases female egg production by on average 8% (4.5 eggs) per consumed salivary mass, whereas mean egg weight was not influenced.4. These results have important implications for the evolution and maintenance of both male nuptial gifts and female polyandry in this and other species.

Determinants of female fecundity in a simultaneous hermaphrodite: the role of polyandry and food availability

“…Material benefits of multiple mating encompass resources that females obtain from males, such as nutrients (e.g., prey items, seminal products), parental investment and/or protection against conspecifics or predators (e.g., Gwynne 1984;Vahed 1998;Engqvist 2007; reviewed in Reynolds 1996;Arnqvist and Nilsson 2000). Furthermore, the receipt of sperm can represent a material benefit, if female reproductive success is limited by the number of sperm that is available to fertilize all the eggs (e.g., Pitnick 1993; Levitan and Petersen 1995;Fjerdingstad and Boomsma 1998;Diaz et al 2010).…”

Evolution of female multiple mating: A quantitative model of the “sexually selected sperm” hypothesis

“…In some systems, for example, where males provide nuptial gifts, multiple mating can increase female fecundity, implying that polyandry is under positive direct selection (e.g., Arnqvist and Nilsson ; Fedorka and Mousseau ; Engqvist ; Alonzo and Pizzari ; Slatyer et al ). However, in other cases polyandry seems more likely to experience negative direct selection (i.e., to be costly for females), for example, because it causes physiological harm or increases disease or predation risk (e.g., Rowe ; Thrall et al ; Chapman et al ; Orsetti and Rutowski ; Wigby and Chapman ), but provides no obvious direct fitness benefit.…”

Should I stay or should I go? Condition- and status-dependent courtship decisions in the scorpionfly Panorpa cognata

“…Mated females would benefit from additional matings because of nuptial gift consumption (Engqvist 2007b), although these nutritional benefits may not always outweigh the costs of enduring a long-lasting courtship interaction. In a recent study, experimental mating trials with mated females were less likely to result in copulations than mating trials involving virgin females (Engqvist 2007c).…”

“…whether to prefer certain males) and female preference (which male to prefer). As females receive both sperm and nutrients during mating (Engqvist 2007b), females with different mating and feeding histories may differ in their general motivation to remain in courtship. Nonmated females will be more dependent on the provision of sperm during copulation than already mated females, and might therefore be more persistent.…”