The trade-off between lifespan and reproduction is central to our understanding of life-history evolution.Laboratory selection experiments have been a powerful tool for quantifying this trade-off, but these tend to be restricted in taxonomic scope, which may limit our understanding. In addition, research often focuses on the trade-off between lifespan and reproductive effort in females, and far less data test how lifespan trades-off with different aspects of male reproduction (e.g., pre-and post-copulatory reproductive investment). Here we examined the trade-off between lifespan and reproduction in females and males of the marula fruit fly, Ceratitis cosyra, (Walker) (Diptera: Tephritidae). To do so, we selected downward or upward on age of peak female egg laying in C. cosyra for twenty generations. In multiple generations, we measured female and male lifespan and body size, female daily and lifetime fecundity, male courtship and mating success, as well as the number of sperm transferred at different ages and sperm storage asymmetry in spermathecae. Our selection regime appeared to achieve its aim; egg laying peaked earlier in females from downward selected lines than upward selected lines. The number of sperm transferred by males decreased in the upward selected flies, but other male reproductive traits remained the same across selection regimes. In contrast, with the wider literature, upward-selection did not extend the lifespan of females or males after ten generations of selection.While lifespan in both sexes responded to selection on female egg laying schedules, it did not do so in a straightforward way. Moreover, male investment in reproductive traits was largely independent of selection regime. These counter-intuitive findings highlight the importance of working with a broad range of species and of considering the trade-off between reproduction and lifespan in both sexes. Significance statementThe trade-off between lifespan and reproduction has been extensively studied in model species using various types of laboratory selection. A limited number of species have been considered using this approach, and the majority of the studies have focused on female, rather than male, reproductive effort.Here, we selected downwards and upwards on age of female reproduction in the marula fruit fly and measured survival, female fecundity, reproductive schedule, as well as male sperm transfer, sperm 4 storage asymmetry, mating and calling success. We found a moderate trade-off between lifespan and early fecundity in downward selected flies, whereas no obvious trade-off was observed in upward selected lines. Regardless of the selection regime, reproductive scheduling was affected in females but not in males, while lifespan was affected in both sexes. Our results show that the timing of reproduction can evolve independently across the sexes, highlighting the importance of studying both females and males.

Life‐history strategies are diverse both across and within species, although the factors shaping this diversity are not fully understood. In the present study, we investigate the life‐history strategies of the marula fruit fly Ceratitis cosyra (Walker) (Diptera: Tephritidae) and how they differ between the sexes. We measure lifespan and age‐dependent reproductive effort in both sexes. In females, reproductive effort is measured as fecundity (egg counts) and for males, courtship behaviour, mating propensity and sperm transfer at ages 5, 15 and 25 days are assayed. Mean ± SE lifespan of flies is 104.6 ± 2.8 days, with females living on average 9 days longer than males. Total female fecundity and time until peak egg production both positively correlate with lifespan. The proportion of males courting and mating is similar at 5 and 15 days, although courtship activity increases and mating success decreases significantly by 25 days. The number of sperm transferred and sperm storage asymmetry are highest at 15 days, with 12 173 ± 826 sperm being stored per female after mating. We also compare life‐history traits in C. cosyra with other tephritids, aiming to determine how niche breadth might contribute to life‐history evolution. In comparison with other tephritids, C. cosyra has a long lifespan and a relatively low lifetime fecundity, although males transfer particularly large numbers of sperm during copulation. These life‐history traits may be associated with the seasonal availability of marulas, which are its preferred native host.

Laboratory experiments are vital to exploring the causes of pollinator loss, but for these experiments to be informative, they should attempt to replicate the hive environment and conserve social interactions. It is unclear how honeybee density and group size affect survival and behaviour in the laboratory. We manipulated cage volume (125-1312 ml) and honeybee group size (10-180 bees) and tested the effects on survival and feeding behaviour.Bees were allowed to regulate their intake from two liquid diets with dry ingredient protein: carbohydrate (P:C) ratios of 0:1 and 1:50 (w /w ). Intake was consistent across cages, showing that feeding behaviour is largely unaffected by cage conditions. High survival was recorded in cages with a volume of 2.08 ml/bee, which falls within the natural range of 1.9-3.8 ml/bee in nest sites, and in groups of < 60 bees. We suggest that cage volume is more important than group size, and that cage dimensions should be adjusted so that each bee has < 3.0 ml of space.cage design / laboratory studies / nutrient regulation / survival / honeybee

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