Female Life Span and Fertility Are Increased by the Ejaculates of Preferred Males

Abstract

Abstract. In animals with internal fertilization, sperm competition among males can favor the evolution of male ejaculate traits that are detrimental to females. Female mating preferences, in contrast, often favor traits in males that are beneficial to females, yet little is known about the effect of these preferences on the evolution of male ejaculates. A necessary condition for female preferences to affect the evolution of male ejaculate characteristics is that females select mates based on a trait correlated with ejaculate quality. Previous work has shown that females of the variable field cricket, Gryllus lineaticeps, prefer males that produce calling songs containing faster and longer chirps. In this study, we tested the hypothesis that females receive more beneficial ejaculates from preferred males. Females were placed on either a high-or a reduced-nutrition diet then mated twice to a male of known song phenotype. Females received only sperm and seminal fluid from males during these matings. There was no effect of male song phenotype on any fitness component for females on the high-nutrition diet. Reduced-nutrition females mated to males that produced preferred song types, however, lived longer, produced more eggs, produced more fertile eggs, and had a higher proportion of their eggs fertilized than those mated to other males. The life-span benefit was positively associated with male chirp duration, and the reproductive benefits were positively associated with male chirp rate. We explored two possible mechanisms for the life span and reproductive benefits. First, a path analysis suggested that part of the effect of male chirp duration on female life span may have been indirect; females mated to males that produced longer chirps showed delayed oviposition, and females that delayed oviposition lived longer. Males that produce longer chirps may thus transfer fewer or less potent oviposition stimulants to females in their seminal fluid. Second, there was a positive correlation between male chirp rate and the number of sperm transferred to females. The fertility benefit may thus have resulted from females receiving more sperm from males that produce faster chirps. Finally, there was a negative phenotypic correlation between male chirp rate and chirp duration, suggesting that females may have to trade off the life span and reproduction benefits when selecting a mate.

Female mate choice plasticity is affected by the interaction between male density and female age in a field cricket

“…This was to ensure balance between the four speaker locations as well as the six treatments. We broadcast a slow chirp rate/short duration male song (1.8 chirps/s, 90 ms) from the speaker, which female G. lineaticeps perceive as being of low quality (Beckers & Wagner, 2011;Wagner, 1996;Wagner & Harper, 2003). The song was broadcast at 70 dB SPL (re: 20 mPa) at 30 cm from the speaker, measured using a Cel-254 dB sound level meter.…”

Diversity, abundance, and sex-specific expression of chemosensory proteins in the reproductive organs of the locust Locusta migratoria manilensis

“…Proteins have also been shown to be involved in phase transition, in particular members of the chemosensory protein (CSP) and ' take-out ' families (Guo et al , 2011 ). Few reports indicate that the male seminal fluid of some insects, including Orthoptera, contains chemicals that can produce physiological or behavioral effects on conspecifics (Wagner and Harper , 2003 ;Simmons , 2011 ). Sex pheromones are also produced by males in their seminal fluid (vaccenyl acetate in Drosophila melanogaster ; Bartelt et al , 1985 ) and could be transferred to females during copulation.…”

Divergent Preferences for Song Structure between a Field Cricket and its Phonotactic Parasitoid

“…Two of the most important factors shaping signal evolution are sexual and natural selection. Females often exhibit strong preferences for signal traits that are correlated with the direct or indirect benefits that the males provide (Welch et al 1998;Wagner and Harper 2003) and male songs commonly co-evolve in response to these preferences (Andersson 1994;Rodriguez et al 2006). Female preferences, however, can differ between closely related species (Gray and Cade 2000;Deily and Schul 2004) or even populations of the same species (Houde and Endler 1990; Morris et al 1996;Hamilton and Poulin 1999) because ecological differences between populations or species affect the nature and strength of selection (Hamilton and Poulin 1999;Rotenberry et al 1996), which can result in signal diversification.…”

“…Female G. lineaticeps (of both parasitized and non-parasitized populations) exhibit preferences for temporal aspects of the mating song such as higher chirp rates and longer chirp durations (Wagner 1996;Wagner and Basolo 2007a;Beckers and Wagner 2011). Under lownutrition conditions, female G. lineaticeps benefit from mating with males that produce these song types because the seminal fluids of these males increase female fecundity and longevity (Wagner and Harper 2003;Tolle and Wagner 2011).…”