Oviposition after sex: mated Anastrepha ludens (Diptera: Tephritidae) females increase oviposition without receiving an ejaculate

Abstract

Mating and receiving ejaculate can alter female insect physiology and postcopulatory behaviour. During mating, females receive both internal and external stimuli and different components in the ejaculate. In insects, these components consist mostly of sperm and male accessory gland secretions. Some of the most important changes associated with receiving male accessory gland secretions are a reduction in female sexual receptivity and an increase in oviposition. However, a clear function for these molecules has not been found in the Mexican fruit fly Anastrepha ludens (Loew) (Diptera: Tephritidae). Here, we tested how the stimulus of mating, receiving a full ejaculate, or only receiving accessory gland secretions can influence ovarian development and oviposition. Our results indicate that the stimulus of mating per se is enough to induce oviposition and increase egg laying in females even if ejaculate is not received, whereas receiving only accessory gland secretions does not increase ovarian development and is not enough to induce oviposition or increase egg production. Further research on the internal and external copulatory courtship of A. ludens will increase our understanding of the role of these secretions in stimulating oviposition independent of ejaculate effects. A biological function for male accessory gland secretions on female behaviour for A. ludens still needs to be found.

Mating, but Not Male Accessory Gland Products, Changes Female Response to Olfactory Cues in Anastrepha Fruit Flies

“…These results reinforce the need for baits based on host volatiles to attract mated females. This population should be targeted as mated females lay more eggs than unmated females and only eggs laid by mated females will develop into larvae which damage fruit and increase population size (Reyes-Hernández et al, 2021). We conclude that copulation does change female behavior in the olfactory response to host volatiles and male sex pheromone in both species, while MAGs alone do not elicit this response.…”

“…This leads to the question of what the functions of MAGs in these two species are. In A. ludens, MAGs injection into females does not decrease female receptivity, influence ovary development, or increase egg number (Abraham et al, 2014(Abraham et al, , 2016Reyes-Hernández et al, 2021), however, the females do require MAGs and sperm for the decrease in receptivity in this species (Abraham et al, 2014(Abraham et al, , 2016. In other Diptera, MAGs can have a number of effects including influencing female longevity (Chapman et al, 1995;Villarreal et al, 2018), increasing oviposition (Kalb et al, 1993) and decreasing remating (Chen et al, 1988;Radhakrishnan and Taylor, 2007).…”

“…Copulation in A. ludens lasts a mean of 73.4 (±6.6) minutes, whereas in A. obliqua it lasts a mean of 47.1 (±0.9) minutes (Aluja et al, 2000). The mechanical stimulus of copulation is enough to induce an increase in number of eggs laid in A. ludens, even when females do not receive an ejaculate when copulating with males with a severed distiphallus (Reyes-Hernández et al, 2021). Furthermore, copulation with all the stimuli in A. ludens causes a higher female response to host volatiles (Robacker and Garcia, 1990), while in A. obliqua copulation does not have that effect (López-Ley et al, 2016).…”

“…The function of MAGs in both A. ludens and A. obliqua is still unknown. In A. ludens, MAGs do not have an effect on mating inhibition, oviposition, or ovary size (Abraham et al, 2014(Abraham et al, , 2016Reyes-Hernández et al, 2021). In A. obliqua, it is only known that females become receptive faster after copulating with a male with a depleted ejaculate (Pérez-Staples and Aluja, 2006), and this phenomenon has been attributed to depletion of MAGs and not of sperm (Pérez-Staples et al, 2008).…”

Characterization of reproductive proteins in the Mexican fruit fly points towards the evolution of novel functions

“…Although the functions of A. ludens Sfps are not yet well understood, mating in this species induces similar post-copulatory changes to those found in other insects. In A. ludens , mating and receiving sperm and Sfps induces oviposition [9] and changes olfactory response from male sex pheromone to host fruit volatiles [4]. Mating also regulates genes with D. melanogaster orthologues involved in egg development, pathogenic defense, wound healing, detoxification, musculature and chemosensory perception in the female, whereas injection with MAG regulates genes with D. melanogaster orthologues related to regulating lifespan in response to stressful environmental factors (i.e.…”