Female access and diet affect insemination success, senescence and the cost of reproduction in the male Mexican fruit fly Anastrepha ludens

Abstract

Hypotheses exploring the influence of dietary conditions on the life history trade-off between survival and reproductive success are extensively tested in female insects, but are rarely explored in males. Here, the impact of dietary quality and female access on age-specific reproduction and survival of male Mexican fruit flies, Anastrepha ludens Loew (Diptera: Tephritidae), are examined. There is a clear cost of female access for males with access to dietary protein, measurable as a decrease in life expectancy, which is further influenced by the age when females are introduced. A protein deficient diet reduces the lifespan benefit of virginity and masks the detrimental effect of female access on male life expectancy. Dietary protein is not necessary for reproductive success, but access to protein at eclosion improves the lifetime reproductive success of males compared to when it is delayed. Overall, reproductive success diminishes as the male flies age, regardless of the dietary conditions, providing evidence for reproductive senescence in males. Delaying the males’ access to a protein source fails to influence the negative effect of age on reproductive ability. Because age specific reproductive rates decline with age, regardless of diet, male fitness does not benefit from lifespan extension. Therefore, males can be expected to allocate available resources towards reproductive effort in favour of extended lifespan, regardless of mate and protein availability.

Female Age Determines Remating Behavior in Wild Mexican Fruit Flies

“…One important issue that complicates comparisons among species and studies is that the terms Byoung^and Bold^do not always mean the same ages. While in some cases the age differences are only a few days, in other cases flies are tested from emergence to senescence (Papanastasiou et al 2011;Benelli et al 2013;Harwood et al 2015). On the other hand, time of sexual maturation differ among species.…”

“…On the other hand, time of sexual maturation differ among species. In A. ludens male reproduction (at 23 ± 3°C) has been described in three phases: i) reproductive onset, from 0 to 20 days, ii) reproductive maturity between 25-30 days old (where the highest levels of insemination success are reached), and iii) reproductive senescence, after 30 days when insemination success begins to decline (Harwood et al 2015). Here, we were interested in testing males and females that were already reproductively mature, and comparing them to older senescent males and females.…”

“…Male age did not affect copulation duration (Pérez-Staples et al 2010), but female age did; older females had longer copulation durations than younger females . Insemination success declines with male age (Harwood et al 2015), sperm viability tends to decline with age in wild flies (Herrera-Cruz M. unpublished data) and older females (35 d-old) have a tendency to store more sperm . Although the exact mechanism by which males inhibit female remating is unknown in this species, there seems to be a synergic effect of both sperm and AGPs (Abraham et al 2014(Abraham et al , 2016.…”

Effects of macronutrient intake on the lifespan and fecundity of the marula fruit fly, Ceratitis cosyra (Tephritidae): Extreme lifespan in a host specialist

“…For example, dietary proteins are detrimental to lifespan (Fanson, Fanson, & Taylor, 2012), but unlike males, females require higher P:C ratios to maximize reproductive effort (e.g., egg production; Le Couteur et al., 2016). Thus, the trade‐off between lifespan and reproduction seems to be more important in females than in males, although there are data showing that this trade‐off also occurs in male Mexican fruit flies Anastrepha ludens , and is related to dietary protein (Harwood et al., 2015). …”

Male age and strain affect ejaculate quality in the Mexican fruit fly

“…In wild males, a previous study found older sexually experienced males (36 d old) to have increased mating success compared to 18‐d‐old males, although no benefits in terms of fecundity or fertility for their mates were found (Pérez‐Staples et al ., ). Insemination success is affected by male age, young males from 0 to 20 d old are in reproductive onset, then reproductive maturity (where males reached the highest reproductive success) is reached between 25 and 30 d, and finally senescence begins at 30 d, when insemination success begins to decrease (Harwood et al ., ). However, there is not a clear atrophy of reproductive organ size at these ages, and even at 57 d of age males have more sperm in their seminal vesicles than younger 9‐d‐old males (Reyes‐Hernández & Pérez‐Staples, ).…”