Artificial selection,pre‐release diet,and gut symbiont inoculation effects on sterile male longevity for area‐wide fruit‐fly management

Longevity is an important life‐history trait for successful and cost‐effective application of the sterile insect technique. Furthermore, it has been shown that females of some species – e.g., Anastrepha ludens (Loew) (Diptera: Tephritidae) – preferentially copulate with ‘old’, sexually experienced males, rather than younger and inexperienced males. Long‐lived sterile males may therefore have greater opportunity to find and mate with wild females than short‐lived males, and be more effective in inducing sterility into wild populations. We explored the feasibility of increasing sterile male lifespan through selection of long‐lived strains and provision of pre‐release diets with added protein, and inoculated with bacterial symbionts recovered from cultures of the gut of wild Anastrepha obliqua (Macquart). Artificial selection for long‐lived A. ludens resulted in a sharp drop of fecundity levels for F1 females. Nevertheless, the cross of long‐lived males with laboratory females produced a female F1 progeny with fecundity levels comparable to those of females in the established colony. However, the male progeny of long‐lived males*laboratory females did not survive in higher proportions than laboratory males. Provision of sugar to A. obliqua adults resulted in increased survival in comparison to adults provided only with water, whereas the addition of protein to sugar‐only diets had no additional effect on longevity. Non‐irradiated males lived longer than irradiated males, and supplying a generic probiotic diet produced no noticeable effect in restoring irradiated male longevity of A. obliqua. We discuss the need to evaluate the time to reach sexual maturity and survival under stress for long‐lived strains, and the inclusion of low amounts of protein and specific beneficial bacteria in pre‐release diets to increase sterile male performance and longevity in the field.     

Female Gryllus vocalis Field Crickets Gain Diminishing Returns from Increasing Numbers of Matings

Although female insects generally gain reproductive benefits from mating frequently, females do not mate unlimited numbers of times. This study asks whether the limit on female mating rate is imposed by trade‐offs between reproduction and survival. Female Gryllus vocalis were given the opportunity to mate 5, 10, or 15 times with novel males, and the effects on daily fecundity (egg production), fertility (proportion of eggs that were fertilized), and female post‐experimental longevity were measured. Females that mated 10 times laid more eggs and had a higher proportion of fertile eggs than females that mated 5 times. However, females that mated 15 times did not lay significantly more eggs or have a higher proportion of fertile eggs than females that mated 10 times. Although number of matings did not affect the date that females laid their last egg, mating more times was associated with a prolonged period of laying fertile eggs. Number of matings did not affect female post‐experimental longevity. Thus, there was no trade‐off between female reproductive effort and survival, even when females mated very large numbers of times. When females were allowed to mate ad libitum, the average number of times that females mated was greater than the number of times that confers maximal fitness. The lack of cost to mating explains why females might be willing to mate beyond the point of diminishing reproductive returns.     

Human longevity at the cost of reproductive success: evidence from global data

A trade‐off between reproduction and somatic maintenance and hence survival is fundamental to life‐history theory. We investigated the relationship between female fecundity and longevity in Homo sapiens using data from 153 countries located all over the world. The raw correlation between life span and fecundity was highly significant with a negative trend. After longevity and fecundity estimates were controlled for by confounding factors such as historical (i.e. human ethnic groups), religious, geographical, socio‐economical and parasitological components, we still observed a negative relationship between the mean female fecundity and the mean longevity in a country. These findings support the hypothesis for the existence of a trade‐off between these two key life‐history traits in humans, as also reported by a recent single longitudinal study in England.     

Intraspecific variability in egg maturation patterns and associated life‐history trade‐offs in a polyembryonic parasitoid wasp

1. Life‐history theory predicts a trade‐off between the resources allocated to reproduction and those allocated to survival. Early maturation of eggs (pro‐ovigeny) is correlated with small body size and low adult longevity in interspecific comparisons among parasitoids, demonstrating this trade‐off. The handful of studies that have tested for similar correlations within species produced conflicting results. 2. Egg maturation patterns and related life‐history traits were studied in the polyembryonic parasitoid wasp, Copidosoma koehleri (Hymenoptera: Encyrtidae). Although the genus Copidosoma was previously reported to be fully pro‐ovigenic, mean egg loads of host‐deprived females almost doubled within their first 6 days of adulthood. 3. The initial egg‐loads of newly emerged females were determined and age‐specific realised fecundity curves were constructed for their clone‐mate twins. The females' initial egg loads increased with body size, but neither body size nor initial egg load was correlated with longevity and fecundity. 4. The variation in initial egg loads was lowest among clone‐mates, intermediate among non‐clone sisters and highest among non‐sister females. The within‐clone variability indicates environmental influences on egg maturation, while the between‐clone variation may be genetically based. 5. Ovaries of host‐deprived females contained fewer eggs at death (at ～29 days) than on day 6. Their egg loads at death were negatively correlated with life span, consistent with reduced egg production and/or egg resorption. Host deprivation prolonged the wasps' life span, suggesting a survival cost to egg maturation and oviposition. 6. It is concluded that adult fecundity and longevity were not traded off with pre‐adult egg maturation.     

EXPERIMENTAL EVOLUTION OF FEMALE TRAITS UNDER DIFFERENT LEVELS OF INTERSEXUAL CONFLICT IN DROSOPHILA MELANOGASTER

A number of studies have documented the evolution of female resistance to mate‐harm in response to the alteration of intersexual conflict in the populations. However, the life‐history consequence of such evolution is still a subject of debate. In this study, we subjected replicate populations of Drosophila melanogaster to different levels of sexual conflict (generated by altering the operational sex ratio) for over 45 generations. Our results suggest that females from populations experiencing higher level of intersexual conflict evolved increased resistance to mate‐harm, in terms of both longevity and progeny production. Females from the populations with low conflict were significantly heavier at eclosion and were more susceptible to mate‐harm in terms of progeny production under continuous exposure to the males. However, these females produced more progeny upon single mating and had significantly higher longevity in absence of any male exposure—a potential evidence of trade‐offs between resistance‐related traits and other life‐history traits, such as fecundity and longevity. We also report tentative evidence, suggesting an increased male cost of interacting with more resistant females.     

Diet and social conditions during sexual maturation have unpredictable influences on female life history trade‐offs

The trade‐off between gametes and soma is central to life history evolution. Oosorption has been proposed as a mechanism by which females can redirect nutrients invested in oocytes into survival when conditions for reproduction are poor. Although positive correlations between oocyte degradation and lifespan have been documented in oviparous insects, the adaptive significance of this process in species with more complex reproductive biology has not been explored. Further, environmental condition is a multivariate state, and combinations of environmental stresses may interact in unpredictable ways. Previous work on the ovoviviparous cockroach, Nauphoeta cinerea, revealed that females manipulated to mate late relative to sexual maturation experience age‐related loss in fecundity because of loss of viable oocytes via apoptosis. This loss in fecundity is correlated with a reduction in female mate choice. Food deprivation while mating is delayed further increases levels of oocyte apoptosis, but the relationship between starvation‐induced apoptosis and life history are unknown. To investigate this, virgin females were either fed or starved from eclosion until provided with a mate at a time known to be suboptimal for fertility. Following mating, females were fed for the duration of their lifespan. We measured lifetime reproductive performance. Contrary to predictions, under conditions of delayed mating opportunity, starved females had greater fecundity, gave birth to more high‐quality offspring and had increased longevity compared with that of fed females. We suggest that understanding proximal mechanisms underlying life history trade‐offs, including the function of oocyte apoptosis, and how these mechanisms respond to varied environmental conditions is critical.     

Effects of multiple mating on the fecundity of an invasive pest (Octodonta nipae): the existence of an intermediate optimal female mating rate

Multiple mating is found in many insect taxa where both of the sexes can mate more than once. For males, this leads to the advantage of increasing their paternity by fertilizing more females. However, there is a trade‐off of resource allocation between reproduction and other life‐history characters. In the present study, the impact of increased mating rate on reproductive fitness of the invasive nipa palm hispid beetle Octodonta nipae Maulik (Coleoptera: Chrysomelidae) is investigated. A series of mating frequencies (i.e. 1, 5, 10, 15, 20 times) is selected from video frame playback, ranking from the minimum to maximum mating rate observed under laboratory conditions over a given time period. Fecundity parameters such as lifetime egg production, egg‐hatching rate, effective oviposition period and longevity are investigated for the evaluation of reproductive efficiency. For female O. nipae, increased fecundity is correlated with the mating frequency. Females mating 15 times lay the largest number of eggs (138.82 ± 6.87) and have a hatching rate of 47.43 ± 4.08%. After mating 20 times, females suffer significant declines in oviposition (90.31 ± 8.38 eggs) and egg‐hatching rate (34.16 ± 4.93%). Moreover, the population growth rate reaches a maximum in the females that mate 15 times. The results show that multiple matings in O. nipae have an intermediate optimal range within which female reproductive success is enhanced, providing empirical evidence for the existence of a trade‐off between costs and benefits during copulation based on resource allocation.     

Age‐Related Male Reproductive Investment in Courtship Display and Nuptial Gifts in a Moth,Ostrinia scapulalis

Due to a trade‐off between current and future reproduction, costly reproductive investments should be increased towards the end of a lifespan when the probability of reproduction becomes low (terminal investment hypothesis). We investigated age‐related changes in male reproductive investment towards courtship display and the spermatophore in three age classes (young, middle‐aged and old) of a monandrous moth, Ostrinia scapulalis. As predicted, old males had higher mating success than young and middle‐aged males in no‐choice tests. Moreover, two‐choice tests revealed that middle‐aged males had a higher success rate than young males because of their higher courtship frequency rather than any female preference for them. It was found that old males produced a larger spermatophore than young and middle‐aged males, suggesting greater reproductive effort. The protein content of spermatophores also tended to increase with male age. Despite the age‐related variation in spermatophore size and protein content, age did not affect female fecundity or longevity. A decrease in the number of sperm in the older males might counteract the nutritional benefit of larger spermatophores. Alternatively, fitness components other than longevity and fecundity may be influenced by male age.     

Sex differences in nutrient intake can reduce the potential for sexual conflict over fitness maximization by female and male crickets

As females and males have different roles in reproduction, they are expected to require different nutrients for the expression of reproductive traits. However, due to their shared genome, both sexes may be constrained in the regulation of nutrient intake that maximizes sex‐specific fitness. Here, we used the Geometric Framework for nutrition to examine the effect of macronutrient and micronutrient intakes on lifespan, fecundity and cuticular hydrocarbons (CHCs) that signal mate quality to prospective mates in female field crickets, Teleogryllus oceanicus. In addition, we contrasted nutritional effects on life‐history traits between males and females to determine how sex differences influence nutrient regulation. We found that carbohydrate intake maximized female lifespan and protein intake influenced CHC expression, while early life fecundity (cumulative fecundity at day 21) and lifetime fecundity were dependent on both macronutrient and micronutrient intakes. Fecundity required different nutrient blends to those required to optimize sperm viability in males, generating the potential for sexual conflict over macronutrient intake. The regulation of protein (P) and carbohydrate (C) intakes by virgin and mated females initially matched that of males, but females adjusted their intake to a higher P:C ratio, 1P:2C, that maximized fecundity as they aged. This suggests that a sex‐specific, age‐dependent change in intake target for sexually mature females, regardless of their mating status, adjusts protein consumption in preparation for oviposition. Sex differences in the regulation of nutrient intake to optimize critical reproductive traits in female and male T. oceanicus provide an example of how sexual conflict over nutrition can shape differences in foraging between the sexes.     

Age at mating and male quality influence female patterns of reproductive investment and survival

The trade‐off between the allocation of resources toward somatic maintenance or reproduction is one of the fundamentals of life history theory and predicts that females invest in offspring at the expense of their longevity or vice versa. Mate quality may also affect life history trade‐offs through mechanisms of sexual conflict; however, few studies have examined the interaction between mate quality and age at first mating in reproductive decisions. Using house crickets (Acheta domesticus), this study examines how survival and reproductive trade‐offs change based on females’ age at first reproduction and exposure to males of varying size. Females were exposed to either a large (presumably high‐quality) or small male at an early (young), middle (intermediate), or advanced (old) age, and longevity and reproductive investment were subsequently tracked. Females mated at a young age had the largest number of eggs but the shortest total lifespans while females mated at older ages produced fewer eggs but had longer total lifespans. The trade‐off between age at first mating and eggs laid appears to be mediated through higher egg‐laying rates and shorter postmating lifespans in females mated later in life. Exposure to small males resulted in shorter lifespans and higher egg‐laying rates for all females indicating that male manipulation of females, presumably through spermatophore contents, varies with male size in this species. Together, these data strongly support a trade‐off between age at first reproduction and lifespan and support the role of sexual conflict in shaping patterns of reproduction.     

Sex differences in the effects of juvenile and adult diet on age‐dependent reproductive effort

Sexual selection should cause sex differences in patterns of resource allocation. When current and future reproductive effort trade off, variation in resource acquisition might further cause sex differences in age‐dependent investment, or in sensitivity to changes in resource availability over time. However, the nature and prevalence of sex differences in age‐dependent investment remain unclear. We manipulated resource acquisition at juvenile and adult stages in decorated crickets, Gryllodes sigillatus, and assessed effects on sex‐specific allocation to age‐dependent reproductive effort (calling in males, fecundity in females) and longevity. We predicted that the resource and time demands of egg production would result in relatively consistent female strategies across treatments, whereas male investment should depend sharply on diet. Contrary to expectations, female age‐dependent reproductive effort diverged substantially across treatments, with resource‐limited females showing much lower and later investment in reproduction; the highest fecundity was associated with intermediate lifespans. In contrast, long‐lived males always signalled more than short‐lived males, and male age‐dependent reproductive effort did not depend on diet. We found consistently positive covariance between male reproductive effort and lifespan, whereas diet altered this covariance in females, revealing sex differences in the benefits of allocation to longevity. Our results support sex‐specific selection on allocation patterns, but also suggest a simpler alternative: males may use social feedback to make allocation decisions and preferentially store resources as energetic reserves in its absence. Increased calling effort with age therefore could be caused by gradual resource accumulation, heightened mortality risk over time, and a lack of feedback from available mates.     

Sexually dimorphic immune response in the harem polygynous Wellington tree weta Hemideina crassidens

Abstract Adult males are often less immunocompetent than females. One explanation for this is that intense sexual selection causes males to trade‐off investment in immunity with traits that increase mating success. This hypothesis is tested in the Wellington tree weta (Hemideina crassidens), a large, sexually dimorphic orthopteran insect in which males possess enormous mandibular weaponry used during fights for access to female mates. Field‐collected males have a significantly greater immune response (greater melanotic encapsulation) than females, suggesting that body condition, longevity or an allied trait is important to male fitness, or that females require materials for egg production that would otherwise be used to boost immunity. Although immunity is expected to trade‐off against reproductive traits in both sexes, there is no significant relationship between immune response and weapon or testes size in males, nor fecundity in females.     

Evolutionary genetics of Drosophila ananassae: evidence for trade-offs among several fitness traits

Correlated responses to bi‐directional selection on thorax length, examined on several life‐history traits and chromosome inversion polymorphisms, have revealed apparent novel trade‐offs in Drosophila ananassae. We provide evidence of trade‐offs between hatching time and pupal period, pupal period and egg‐pupa development time, and pupal period and larval development time (LDT). Body size shows positive correlations with ovariole number, LDT and DT (egg–fly). We provide evidence of sexual dimorphism for trade‐offs between longevity and body size and starvation and longevity in females only. Trade‐offs between wing/thorax (W/T) ratio and longevity, W/T ratio and starvation, and DT (egg‐ fly) and longevity are evident in males only. Sexual dimorphism is also evident for inversion polymorphism with body size and longevity. A longevity assay suggests that low line females outlived high line females whereas high line males outlived low line males. The mean longevity in males is negatively correlated with the 2L‐ST and 3R‐ST arrangement frequencies whereas the 3L‐ST arrangement frequency is positively correlated with the mean longevity in males but opposite arrangements are found in females. Absolute starvation resistance is negatively correlated with 2L‐ST and 3R‐ST chromosome arrangements and results in a trade‐off between longevity and absolute starvation resistance in females. Analyses of fecundity, hatchability, and viabilities based on age intervals in both G₁₀ and G₁₃ suggest that the early reproduction is favoured in D. ananassae. The productivity percentage is highest in the high line and there is no effect of late reproduction on it. Overall, we provide some unravelled trade‐offs and striking sex differences, which may help in understanding the life‐history evolution of the species. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90 , 669–685.     

Heterosis in age‐specific selected populations of a seed beetle: Sex differences in longevity and reproductive behavior

We tested mutation accumulation hypothesis for the evolution of senescence using short‐lived and long‐lived populations of the seed‐feeding beetle, Acanthoscelides obtectus (Say), obtained by selection on early‐ and late‐life for many generations. The expected consequence of the mutation accumulation hypothesis is that in short‐lived populations, where the force of natural selection is the strongest early in life, the late‐life fitness traits should decline due to genetic drift which increases the frequency of mutations with deleterious effects in later adult stages. Since it is unlikely that identical deleterious mutations will increase in several independent populations, hybrid vigor for late‐life fitness is expected in offspring obtained in crosses among populations selected for early‐life fitness traits. We tested longevity of both sexes, female fecundity and male reproductive behavior for hybrid vigor by comparing hybrid and nonhybrid short‐lived populations. Hybrid vigor was confirmed for male virility, mating speed and copulation duration, and longevity of both sexes at late ages. In contrast to males, the results on female fecundity in short‐lived populations did not support mutation accumulation as a genetic mechanism for the evolution of this trait. Contrary to the prediction of this hypothesis, male mating ability indices and female fecundity in long‐lived populations exhibited hybrid vigor at all assayed age classes. We demonstrate that nonhybrid long‐lived populations diverged randomly regarding female and male reproductive fitness, indicating that sexually antagonistic selection, when accompanied with genetic drift for female fecundity and male virility, might be responsible for overriding natural selection in the independently evolving long‐lived populations.     

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

In insects, lifespan and reproduction are strongly associated with nutrition. The ratio and amount of nutrients individuals consume affect their life expectancy and reproductive investment. The geometric framework (GF) enables us to explore how animals regulate their intake of multiple nutrients simultaneously and determine how these nutrients interact to affect life‐history traits of interest. Studies using the GF on host‐generalist tephritid flies have highlighted trade‐offs between longevity and reproductive effort in females, mediated by the protein‐to‐carbohydrate (P:C) ratio that individuals consume. Here, we tested how P and C intake affect lifespan (LS) in both sexes, and female lifetime (LEP), and daily (DEP) egg production, in Ceratitis cosyra, a host‐specialist tephritid fly. We then determined the P:C ratio that C. cosyra defends when offered a choice of foods. Female LS was optimized at a 0:1 P:C ratio, whereas to maximize their fecundity, females needed to consume a higher P:C ratio (LEP = 1:6 P:C; DEP = 1:2.5 P:C). In males, LS was also optimized at a low P:C ratio of 1:10. However, when given the opportunity to regulate their intake, both sexes actively defended a 1:3 P:C ratio, which is closer to the target for DEP than either LS or LEP. Our results show that female C. cosyra experienced a moderate trade‐off between LS and fecundity. Moreover, the diets that maximized expression of LEP and DEP were of lower P:C ratio than those required for optimal expression of these traits in host‐generalist tephritids or other generalist insects.     

Evaluating the life‐history trade‐off between dispersal capability and reproduction in wing dimorphic insects: a meta‐analysis

A life‐history trade‐off exists between flight capability and reproduction in many wing dimorphic insects: a long‐winged morph is flight‐capable at the expense of reproduction, while a short‐winged morph cannot fly, is less mobile, but has greater reproductive output. Using meta‐analyses, I investigated specific questions regarding this trade‐off. The trade‐off in females was expressed primarily as a later onset of egg production and lower fecundity in long‐winged females relative to short‐winged females. Although considerably less work has been done with males, the trade‐off exists for males among traits primarily related to mate acquisition. The trade‐off can potentially be mitigated in males, as long‐winged individuals possess an advantage in traits that can offset the costs of flight capability such as a shorter development time. The strength and direction of trends differed significantly among insect orders, and there was a relationship between the strength and direction of trends with the relative flight capabilities between the morphs. I discuss how the trade‐off might be both under‐ and overestimated in the literature, especially in light of work that has examined two relevant aspects of wing dimorphic species: (1) the effect of flight‐muscle histolysis on reproductive investment; and (2) the performance of actual flight by flight‐capable individuals.     

Male mate preference as an agent of fecundity selection in a polymorphic salamander

Color polymorphisms are associated with variation in other traits which may affect individual fitness, and these color‐trait associations are expected to contribute to nonrandom mating in polymorphic species. The red‐backed salamander (Plethodon cinereus) exhibits a polymorphism in dorsal pattern: striped and unstriped, and previous studies have suggested that they may mate nonrandomly. However, the mechanism(s) contributing to this behavior remain unclear. Here we consider the role that male preference may have in driving mating behavior in P. cinereus. We limit our focus to striped individuals because this morph is most likely to be choosy given their dominant, aggressive behavioral profiles relative to unstriped males. Specifically, we evaluated (a) whether striped males preferentially associate with females with respect to her dorsum color, size, and body condition and (b) if so, whether female traits are evaluated via visual or chemical cues. We also considered whether the frequency of another male social behavior, nose taps, was associated with mate preferences. We found that striped male P. cinereus nose tapped more often to preferred females. However, males only assessed potential mates via chemical cues, preferring larger females overall. Reproductive phenology data on a sample of gravid females drawn from the same population indicated that the color morphs do not differ in reproductive traits, but larger females have greater fecundity. Given our findings, we conclude that female P. cinereus are under fecundity selection, mediated by male preference. In this manner, male mating behavior contributes to observations of nonrandom mate associations in this population of P. cinereus.     

THE EVOLUTION OF ALTERNATIVE REPRODUCTIVE TACTICS IN MALE CARDIOCONDYLA ANTS

Alternative reproductive tactics are often associated with discontinuous variation in morphology but may evolve independent from each other. Based on life‐history data and a phylogeny we examine how male morphology and reproductive behavior are linked in the evolution of the ant genus Cardiocondyla. Wingless Cardiocondyla males engage in lethal fighting for access to female sexuals, whereas winged males disperse and mate away from the nest. This basic pattern shows considerable variation across species. A phylogeny based on ～3 kbp sequence data shows that male diphenism and lethal fighting are ancestral traits tightly linked in evolution. Winged males were lost convergently in several species groups, apparently in response to the low probability of encountering female sexuals in nests without a resident fighter male. An early dichotomy separates two clades with alternative male morphologies and fighting behavior, but phenotype and fighting strategy are not correlated with the presence of winged males.     

The role of the tolerance–fecundity trade‐off in maintaining intraspecific seed trait variation in a widespread dimorphic herb

Coexistence of species with different seed sizes is a long‐standing issue in community ecology, and a trade‐off between fecundity and stress tolerance has been proposed to explain co‐occurrence in heterogeneous environments. Here we tested an intraspecific extension of this model: whether such trade‐off also explains seed trait variation among populations of widespread plants under stress gradients. We collected seeds from 14 populations of Plantago coronopus along the Atlantic coast in North Africa and Europe. This herb presents seed dimorphism, producing large basal seeds with a mucilaginous coat that facilitates water absorption (more stress tolerant), and small apical seeds without coats (less stress tolerant). We analysed variation among populations in number, size and mucilage production of basal and apical seeds, and searched for relationships between local environment and plant size. Populations under higher stress (higher temperature, lower precipitation, lower soil organic matter) had fewer seeds per fruit, higher predominance of basal relative to apical seeds, and larger basal seeds with thicker mucilaginous coats. These results strongly suggest a trade‐off between tolerance and fecundity at the fruit level underpins variation in seed traits among P. coronopus populations. However, seed production per plant showed the opposite pattern to seed production per fruit, and seemed related to plant size and other life‐cycle components, as an additional strategy to cope with environmental variation across the range. The tolerance–fecundity model may constitute, under stress gradients, a broader ecological framework to explain trait variation than the classical seed size–number compromise, although several fecundity levels and traits should be considered to understand the diverse strategies of widespread plants to maximise fitness in each set of local conditions.     

Reproduction-longevity trade-offs reflect diet, not adaptation

A tenet of life history evolution is that allocation of limited resources results in trade‐offs, such as that between reproduction and lifespan. Reproduction and lifespan are also influenced proximately by differences in the availability of specific nutrients. What is unknown is how the evolution of the ability to use a nutritionally novel diet is reflected in this fundamental trade‐off. Does the evolution of the ability to use a nutritionally novel food maintain the trade‐off in reproduction and longevity, or do the proximate effects of nutrition alter the adapted trade‐off? We tested this by measuring trade‐offs in male milkweed bugs, Oncopeltus fasciatus, fed either an adapted diet of sunflower or the ancestral diet of milkweed. Sunflower‐fed males lived longer but invested less in reproduction, both in mating and fertility. Milkweed‐fed males invested in both mating and fertility at the expense of survival. The evolution of an expanded diet was not constrained by the existing trade‐off, but instead was accompanied by a different trade‐off between reproduction and longevity. We suggest that this occurs because diets differ in promoting germ line development or longevity.