Female Life History Research Articles

Can sexual selection drive female life histories? A comparative study on Galliform birds

Sexual selection has been identified as a major evolutionary force shaping male life history traits but its impact on female life history evolution is less clear. Here we examine the impact of sexual selection on three key female traits (body size, egg size and clutch size) in Galliform birds. Using comparative independent contrast analyses and directional discrete analyses, based on published data and a new genera-level supertree phylogeny of Galliform birds, we investigated how sexual selection [quantified as sexual size dimorphism (SSD) and social mating system (MS)] affects these three important female traits. We found that female body mass was strongly and positively correlated with egg size but not with clutch size, and that clutch size decreased as egg size increased. We established that SSD was related to MS, and then used SSD as a proxy of the strength of sexual selection. We found both a positive relationship between SSD and female body mass and egg size and that increases in female body mass and egg size tend to occur following increases in SSD in this bird order. This pattern of female body mass increases lagging behind changes in SSD, established using our directional discrete analysis, suggests that female body mass increases as a response to increases in the level of sexual selection and not simply through a strong genetic relationship with male body mass. This suggests that sexual selection is linked to changes in female life history traits in Galliformes and we discuss how this link may shape patterns of life history variation among species.

Beauty in the eye of the beholder: the two blue opsins of lycaenid butterflies and the opsin gene-driven evolution of sexually dimorphic eyes

Although previous investigations have shown that wing coloration is an important component of social signaling in butterflies, the contribution of opsin evolution to sexual wing color dichromatism and interspecific divergence remains largely unexplored. Here we report that the butterfly Lycaena rubidus has evolved sexually dimorphic eyes due to changes in the regulation of opsin expression patterns to match the contrasting life histories of males and females. The L. rubidus eye contains four visual pigments with peak sensitivities in the ultraviolet (UV; lambdamax=360 nm), blue (B; lambdamax=437 nm and 500 nm, respectively) and long (LW; lambdamax=568 nm) wavelength range. By combining in situ hybridization of cloned opsin-encoding cDNAs with epi-microspectrophotometry, we found that all four opsin mRNAs and visual pigments are expressed in the eyes in a sex-specific manner. The male dorsal eye, which contains only UV and B (lambdamax=437 nm) visual pigments, indeed expresses two short wavelength opsin mRNAs, UVRh and BRh1. The female dorsal eye, which also has the UV and B (lambdamax=437 nm) visual pigments, also contains the LW visual pigment, and likewise expresses UVRh, BRh1 and LWRh mRNAs. Unexpectedly, in the female dorsal eye, we also found BRh1 co-expressed with LWRh in the R3-8 photoreceptor cells. The ventral eye of both sexes, on the other hand, contains all four visual pigments and expresses all four opsin mRNAs in a non-overlapping fashion. Surprisingly, we found that the 500 nm visual pigment is encoded by a duplicate blue opsin gene, BRh2. Further, using molecular phylogenetic methods we trace this novel blue opsin gene to a duplication event at the base of the Polyommatine+Thecline+Lycaenine radiation. The blue opsin gene duplication may help explain the blueness of blue lycaenid butterflies.

Effect of Nitrogen Fertility on Reproduction and Development of Citrus Mealybug,Planococcus citriRisso (Homoptera: Pseudococcidae), Feeding on Two Colors of Coleus,Solenostemon scutellarioidesL. Codd

The effects of nitrogen concentration on the reproduction and development of citrus mealybug, Planococcus citri, were studied on two colors of coleus, Solenostemon scutellarioides. Green and red-variegated coleus plants were supplied with varying applied nitrogen concentrations (0, 25, 50, 100, 200, and 400 ppm) for 32 d before being artificially inoculated with citrus mealybugs. Female citrus mealybug life history parameters including eggs contained within the egg mass and respective body cavity, body length (mm), and developmental time (d) were measured. A modified micro-Kjeldahl digestion procedure followed by colormetric assay was conducted twice throughout the study to assess leaf nitrogen concentration. The results of this study show that the citrus mealybug life history parameters were influenced by the applied nitrogen concentrations (ppm), leaf nitrogen concentration (%), and total moisture content (g). Citrus mealybugs feeding on both green and red-variegated coleus, receiving the high nitrogen fertilizer concentrations (200 and 400 ppm) had the greatest egg loads, were larger in size, and had the shortest developmental times. Leaf nitrogen concentration also affected the citrus mealybug life history parameters with those mealybugs feeding on plants containing the highest leaf nitrogen contents having the greatest egg loads, larger in size, and the shortest developmental times. In addition, total plant moisture content impacted the citrus mealybug life history parameters similar to leaf nitrogen concentration. However, this was based on plant architecture whereas percent plant moisture content for both green- and red-variegated coleus was comparatively similar for all nitrogen concentrations. The life history parameters measured were more pronounced on green coleus compared with red-variegated coleus, perhaps because of nitrogen allocation differences between the two coleus colors. Thus, higher nitrogen concentrations, in the form of supplemental fertilizers used in greenhouse production systems, leads to an increase in the performance of citrus mealybugs as defined by increased egg loads, larger mature females, and shorter developmental times on coleus plants. These results indicate that the implementation of proper fertilizer practices may lessen the likelihood of dealing with extensive insect outbreaks, thus potentially reducing insecticide use.

Demographic and Female Life History Parameters of Free-Ranging Chimpanzees at the Chimpanzee Rehabilitation Project, River Gambia National Park

We analyzed fertility and mortality records for 113 provisioned, free-ranging chimpanzees at the River Gambia National Park, The Gambia. The chimpanzees are rehabilitated orphans released by the Chimpanzee Rehabilitation Project (CRP), and their descendants born in a natural environment. Females experienced their 1st births at an average age of 14.3 yr, with average interbirth intervals of 68 mo. Despite limited provisioning, reproductive parameters in both released and 1st-generation females resembled those of wild chimpanzees and showed seasonal fluctuations. Mortality rates were low compared to those for wild chimpanzees, particularly for infants and juveniles; life expectancy at birth was 23.6 yr for females and 18 yr for males. The results have implications for our understanding of variation in reproductive parameters between captive and wild chimpanzees. We also discuss issues related to chimpanzee conservation and captive rearing.

Does testis weight decline towards the Subarctic? A case study on the common frog, Rana temporaria

Interpopulation comparisons of variation in resource availability and in allocation patterns along altitudinal and latitudinal gradients allow insights into the mechanisms shaping the life history of animals. Patterns of between-population differences in female life history traits have been studied intensively across a wide range of taxa, but similar investigations in males have remained scarce. To study if testis weight-a measure of reproductive investment-varies on a geographical scale in anurans, we focussed on the variation in relative testis weight (RelTW) and asymmetry in 22 populations of the common frog Rana temporaria along a 1,600-km latitudinal transect across the Scandinavian peninsula. We found that RelTW decreased towards the north. Body mass and body length both had independent positive effects on testes mass. We found evidence for directional asymmetry (DA) in testis weight with the right testis being larger than the left. The level of DA in testis weight was not related to latitude, but both body mass and testes mass had independent positive effects on asymmetry. We discuss the northwards decrease in RelTW in terms of a decreased reproductive investment as a possible consequence of harsher environmental conditions, and perhaps also, weaker sexual selection in the north than in the south.

Sperm influences female hibernation success, survival and fitness in the bumble–beeBombus terrestris

We present evidence that in the absence of the transfer of male gland compounds in the ejaculate as well as of behavioural male traits, such as mate guarding or harming of females, sperm itself affects female life-history traits such as hibernation success, female longevity and female fitness. Using the bumble-bee Bombus terrestris, we artificially inseminated queens (females) with sperm from one or several males and show that sire groups (groups of brother males) vary in their effects on queen hibernation survival, longevity and fitness. In addition, multiply inseminated queens always had a lower performance as compared to singly inseminated queens. Apart from these main effects, sire groups (in situations of multiple insemination) affected queen longevity and fitness not independently of each other, i.e. certain sire group combinations were more harmful to queens than others. So far, the cause(s) of these effects remain(s) elusive. Harmful male traits as detected here are not necessarily expected to evolve in social insects because males depend on females for a successful completion of a colony cycle and thus have strong convergent interests with their mates.

Worldwide Variation in Life-Span Sexual Dimorphism and Sex-Specific Environmental Mortality Rates

In all human populations mean life span of women generally exceeds that of men, but the extent of this sexual dimorphism varies across different regions of the world. Our purpose here is to study, using global demographic and environmental data, the general tendency of this variation and local deviations from it. We used data on male and female life history traits and environmental conditions for 227 countries and autonomous territories; for each country or territory the life-span dimorphism was defined as the difference between mean life spans of women and men. The general tendency is an increase of life-span dimorphism with increasing average male-female life span; this tendency can be explained using a demographic model based on the Makeham-Gompertz equation. Roughly, the life-span dimorphism increases with the average life span because of an increase in the duration of expressing sex- and age-dependent mortality described by the second (exponential) term of the Makeham-Gompertz equation. Thus we investigated the differences in male and female environmental mortality described by the first term of the Makeham-Gompertz equation fitted to the data. The general pattern that resulted was an increase in male mortality at the highest and lowest latitudes. One plausible explanation is that specific factors tied to extreme latitudes influence males more strongly than females. In particular, alcohol consumption increases with increasing latitude and, on the contrary, infection pressures increase with decreasing latitude. This finding agrees with other observations, such as an increase in male mortality excess in Europe and Christian countries and an increase in female mortality excess in Asia and Muslim countries. An increase in the excess of female mortality may also be due to increased maternal mortality caused by an increase in fertility. However, this relation is not linear: In regions with the highest fertility (e.g., in Africa) the excess of female mortality is smaller than in regions with relatively lower fertility (e.g., in Asia). A possible explanation of this phenomenon is an evolutionary adaptation of women to the pressures of extremely high fertility by means of some reduction of their maternal mortality.

Demography, female life history, and reproductive profiles among the chimpanzees of Mahale.

Demography provides critical data to increase our understanding of the evolution, ecology, and conservation of primate populations. The chimpanzees of the Mahale Mountains National Park, Tanzania, have been studied for more than 34 yr on the basis of individual identification and standardized attendance records. From this long-term study, we derived the following demographic data: The major cause of death was disease (48%), followed by senescence (24%) and within-species aggression (16%). Fifty percent of Mahale chimpanzees died before weaning. The median ages of female life history variables were: first maximal swelling, 10.0 yr (n = 5); emigration, 11.0 yr (n = 11); and first birth, 13.1 yr (n = 5). The median period of adolescent infertility was 2.8 yr (n = 4) when calculated from the age at immigration to that at first birth. Female fecundity was highest between 20 and 35 yr of age, with an annual birth rate of 0.2. Twenty-six females that were observed from a young age (10-13 yr) to death at various ages (15-40 yr) gave birth to an average of 3.9 and weaned an average of 1.4 offspring. Twenty-five females that were observed from middle age (18-33 yr) to death in older age (31-48) gave birth to an average of 2.7 and weaned an average of 2.0 offspring. The post-reproductive lifespan for female chimpanzees was defined as the number of years that passed from the year when the last offspring was born to the year when the female died, minus 5. Twenty-five percent of old females had a post-reproductive lifespan. The interbirth interval after the birth of a son (x = 72 mo) tended to be longer than that after the birth of a daughter (x = 66 mo). The extent of female transfer, which is a rule in chimpanzees, is influenced by the size and composition of the unit group and size of the overall local community.

Life in the slow lane? Demography and life histories of male and female sifaka (Propithecus verreauxi verreauxi)

AbstractA 16‐year study of wild, unprovisioned sifaka Propithecus verreauxi verreauxi at Beza Mahafaly in south‐west Madagascar provides estimates of age‐specific fertility, mortality, and dispersal in a population of 426 marked animals, and longitudinal records of individual life histories. Sifaka females give birth for the first time later and live longer, for their size, than mammals in other orders; they also give birth later and continue reproducing longer, for their size, than other primates. Theory postulates that these features, commonly referred to as bet‐hedging, evolve in unpredictable environments in association with widely varying infant survival and a trade‐off between reproductive effort and adult survival. The climate of south‐west Madagascar is highly unpredictable compared to almost all other regions in the tropics with similar average rainfall, and we argue that sifaka females are bet‐hedgers par excellence. Male sifaka, in contrast, become reproductively active at an earlier age than females, and are less likely to have long lives than females. The atypical direction of this asymmetry between males and females reflects a ‘slowing down’ of female life histories rather than a ‘speeding up’ of male life histories. Two other unusual features of sifaka biology and behaviour may be linked to the unpredictability of Madagascar's climate: intense local competition between females, and a sex ratio at birth strongly biased in favour of males in most years. In drought years, reproductive females must cope with suddenly intensified resource constraints. This, in turn, may strongly limit the number of ‘breeding slots’ available over the long‐term for females.

Sexual cannibalism in Nephila plumipes as a consequence of female life history strategies

Abstract The evolution of sexual cannibalism has been modelled as both an adaptive and nonadaptive female strategy. Recent evidence from several species suggests a connection between female foraging and sexual cannibalism, but the precise benefits for females have remained obscure. Here, we investigate the difference between cannibalistic and noncannibalistic female Nephila plumipes by removing the potential nutritional benefit of cannibalism. Courting and mating males that were killed by a female were immediately removed so that the female could not consume them. Nevertheless, cannibalistic females gained more mass from maturation to oviposition and produced larger first clutches than noncannibalistic females, although cannibalistic females matured at a smaller size and mass than noncannibalistic females. In juvenile instars, mass gain was generally smaller in females that moulted in a good condition but intermoult intervals were shorter. However, the time from maturity to oviposition was not shorter in females that matured in a good condition. Male behaviour did not differ according to the risk of cannibalism. We suggest that sexual cannibalism in N. plumipes is a side-effect of an increased foraging vigour of females that matured at a smaller size and body mass. Selection pressure on males to avoid cannibalism may be weak because of limited mating opportunities.

Fat distribution patterns in young amenorrheic females.

The present study analyzes body fat distribution, a well-known and important indicator of reproductive capability, in young women between 18 and 28 years of age (mean=23.3 years) suffering from secondary amenorrhea and therefore temporary infertility resulting from self-starvation. Body composition parameters estimated by means of dual energy x-ray absorptiometry and the fat distribution index, indicating body shape, were compared with those of healthy controls. Although members of the infertile, amenorrheic group exhibited dramatically low body weight and total amount of body fat, and therefore a marked negative energy balance in comparison with the healthy controls, the sex-specific fat distribution patterns did not differ between infertile and fertile young women. In contrast, the lower the weight and total fat amount, the more gynoid the fat distribution, even in infertile women. This observation may be interpreted in an evolutionary sense: Our ancestors had to cope with frequent food shortages, even starvation, and therefore lengthy periods of negative energy balance. In addition to pregnancy and lactation, temporary infertility as a result of long-term negative energy balance was not an uncommon phenomenon in female life histories. Nevertheless, after a time of plenty, reproductive function recovered, and therefore the gynoid fat distribution patterns in temporarily infertile young women may be interpreted as signal of reproductive capability, which resumes after a time of surplus.

SEXUAL DIMORPHISM WITH FEMALE DEMOGRAPHIC DOMINANCE: AGE, SIZE, AND SEX RATIO AT MATURATION

Under the influence of natural and sexual selection, males and females will often differ in the costs and benefits of achieving some particular body size; we might therefore expect to find them growing at different rates for different times, and dying on different schedules. The analysis of sexual dimorphism presented here assumes that life histories are optimized over three key variables: activity level (or “effort”) during the juvenile stage, duration of the juvenile stage, and size at maturation. Reproduction is taken to be semelparous (or monocarpic), reproductive success is size dependent, and females are demographically dominant. Juvenile male and female life histories are assumed to be “structurally identical” (i.e., governed by identical functions of activity, size, and development time). Under these conditions, sexually dimorphic life histories readily arise when features of juvenile behavior and development are adjusted to maximize r in response to gender-specific selection pressures on adults. ...

Underground mating in the fiddler crab Uca tetragonon: the association between female life history traits and male mating tactics.

Brood size and other life-history traits of females affect male investment in mating. Female Uca tetragonon, producing relatively small broods, were attracted to the burrows of males for underground mating (UM) while carrying eggs. Most UM females released larvae and ovulated new broods during the pairing, averaging 3.9 days. While a female was incubating one brood, another brood was developing within the ovaries because the females were feeding adequately during incubation. These findings suggest that in U. tetragonon, a small-brood species, females increase the total number of broods produced by breeding continually. In contrast, in large-brood species, feeding by ovigerous females is relatively brief and not enough to prepare the next brood during incubation, inducing temporal separation between incubation and brood production. Unlike females in other ocypodids where females with large broods remain in the breeding burrows of males, most female U. tetragonon left the male after UM. Wandering in female U. tetragonon after the pairs separate may occur because their small broods are adequately protected by an abdominal flap. Relative brood size probably determines the vulnerability of the incubated broods to the females' surface behavior. Hence, male reproductive success in large-brood species may decrease greatly if males expel their mates after ovulation, although this is not necessarily so in small-brood species. Whether the male drives away the female or not may depend on which behavior within either small- or large-brood species yields the greater male reproductive success. In U. tetragonon some females extruded eggs in their own burrows after surface mating as well as in males' burrows after UM. It was unclear whether females chose a male with a larger burrow as an UM mate unlike several large-brood species. Burrows of both UM males and ovigerous females in U. tetragonon were relatively smaller than those in some large-brood species, indicating that incubation of small broods does not require large burrows. Rather than benefits of UM by female choice, wandering resulting from intersexual conflict, and sperm competition may explain why some females mate in males' burrows in this small-brood species.

The genetic structure of female life history in D. melanogaster: comparisons among populations.

Two questions were addressed: (1) What is the genetic variance-covariance structure of a suite of four female life history traits in D. melanogaster? and (2) Does the genetic architecture of these traits differ among populations? Three populations of D. melanogaster were studied. Genetic variances and covariances were estimated by sib analysis three times for each population: immediately upon establishment of populations in the laboratory, and subsequently after approximately 6 months and 2 years of laboratory culture. Entire genetic variance-covariance matrices, as well as their individual components, were compared between populations by means of likelihood ratio tests. All traits studied were significantly heritable in at least one-half of estimates. Despite large sample sizes, additive genetic covariances were for the most part not statistically significant, and only two significant negative covariance estimates were obtained throughout the experiments. Therefore, these experiments provide little support for evolutionary life history theories that are based on negative genetic correlations among life history components. Neither do they support the idea that genetic variance for fitness components is maintained by trade-offs. Evidence suggests that the G matrix of one population was initially different from those of the other two populations. Those differences disappeared after 2 years of laboratory culture. At the level of individual (co)variance components, there were relatively few differences among populations, and the overall impression was that the three populations had generally similar genetic architectures for the traits studied.

Sex-ratio optimization with helpers at the nest

In many cooperatively breeding animals, offspring produced earlier in life assist their parents in raising subsequent broods. Such helping behaviour is often confined to offspring of one sex. Sex-allocation theory predicts that parents overproduce offspring of the helping sex, but the expected degree of sex-ratio bias was thought to depend on specific details of female and male life histories, hampering empirical tests of the theory. Here we demonstrate the following two theories. (i) If all parents produce the same sex ratio, the evolutionarily stable sex ratio obeys a very simple rule that is valid for a general class of life histories. The rule predicts that the expected sex-ratio bias depends on the product of only two parameters which are relatively easily measured: the average number of helping offspring per nest and the relative contribution to offspring production per helper. (ii) If the benefit of helping varies between parents, and parents facultatively adjust the sex ratio accordingly, then the population sex ratio is not necessarily biased towards the helping sex. For example, in line with empirical evidence, if helpers are produced under favourable conditions and parents do not adjust their clutch size to the number of helpers, then a surplus of the non-helping sex is expected.

Prolactin and mammary gland development.

Prolactin (PRL) regulates the development of the mammary gland at three stages in the reproductive life history of females. The first stage is mammary gland organogenesis, during which PRL contributes to the maturation of the mammary glands from a primary ductal system, which grows from terminal end buds, to the fully mature nonpregnant gland. The mature mammary gland is characterized by an absence of terminal end buds, and the development of a highly branched architecture, which is decorated by lobular buds. During pregnancy PRL, placental lactogens, and progesterone stimulate the expansion and physiological differentiation of the lobuloalveolar system from the lobular buds. After delivery PRL, in the context of falling progesterone, stimulates the final induction of milk protein gene expression and lactation. PRL acts directly on the mammary epithelium, and indirectly by stimulating luteal progesterone secretion in rodents. Disruption of the genes for PRL and the PRL receptor, as well as those for transcription factors important in mammary gland regulation (Stat proteins), have provided a new set of animal models with which to study normal mammary gland development and the relationships of PRL to breast carcinogenesis. Two major deficiencies in our current knowledge of PRL actions are our understanding of the role of epithelial-stromal interactions in PRL-induced mammary morphogenesis, and the identity of developmentally important genes that are regulated by PRL during normal mammary gland organogenesis.

Nuptial Gifts, Resource Budgets, and Reproductive Output in a Polyandrous Butterfly

Many female insects receive material during mating, referred to as “nuptial gifts,” that may increase the female’s resource budget. This investigation examines how nuptial gifts influence female nitrogen and carbon budgets in a polyandrous butterfly, Pieris napi. During mating, a virgin male of this species transfers a large and nutritious ejaculate containing 14% nitrogen by dry mass. The amount of nitrogen transferred is equivalent to that in ∼70 eggs. Females use the male-transferred nutrients to increase their pool of nutrients used for egg production and show a positive relationship between amount of ejaculate material received and lifetime reproductive output. It is clear that for multiply mated females, nitrogen derived from male nuptial gifts is essential for a balanced nitrogen budget. As in earlier studies, female thorax mass decreased with age, indicating that old females of P. napi are able to use more of the resources from their thorax than young females. Since male-transferred material also increases female longevity, multiply mated females also use more of their resources from the thorax. Consequently, multiply mated females have a relatively higher reproductive investment than singly mated females, i.e., they transform a larger part of their body reserves to egg production. These results are important for studies that involve male-transferred nutrients in female life history patterns as well as for investigations of links between nuptial gifts and sexual selection theory. When the value of nuptial gifts is determined only on the nutritional value of the gift itself rather than the function within the female, there is an obvious risk for incorrect conclusions.

NUPTIAL GIFTS, RESOURCE BUDGETS, AND REPRODUCTIVE OUTPUT IN A POLYANDROUS BUTTERFLY

Many female insects receive material during mating, referred to as “nuptial gifts,” that may increase the female’s resource budget. This investigation examines how nuptial gifts influence female nitrogen and carbon budgets in a polyandrous butterfly, Pieris napi. During mating, a virgin male of this species transfers a large and nutritious ejaculate containing 14% nitrogen by dry mass. The amount of nitrogen transferred is equivalent to that in ∼70 eggs. Females use the male-transferred nutrients to increase their pool of nutrients used for egg production and show a positive relationship between amount of ejaculate material received and lifetime reproductive output. It is clear that for multiply mated females, nitrogen derived from male nuptial gifts is essential for a balanced nitrogen budget. As in earlier studies, female thorax mass decreased with age, indicating that old females of P. napi are able to use more of the resources from their thorax than young females. Since male-transferred material also increases female longevity, multiply mated females also use more of their resources from the thorax. Consequently, multiply mated females have a relatively higher reproductive investment than singly mated females, i.e., they transform a larger part of their body reserves to egg production. These results are important for studies that involve male-transferred nutrients in female life history patterns as well as for investigations of links between nuptial gifts and sexual selection theory. When the value of nuptial gifts is determined only on the nutritional value of the gift itself rather than the function within the female, there is an obvious risk for incorrect conclusions.

Elevated predation risk changes mating behaviour and courtship in a fiddler crab

The fiddler crab, Uca beebei, lives in individually defended burrows, in mixed-sex colonies on intertidal mud flats. Avian predation is common, especially of crabs unable to escape into burrows. Mating pairs form in two ways. Females either mate on the surface at their burrow entrance ('surface mating') or leave their own burrow and sequentially enter and leave ('sample') courting males' burrows, before staying in one to mate underground ('burrow mating'). We tested whether perceived predation risk affects the relative frequency of these mating modes. We first observed mating under natural levels of predation during one biweekly, semi-lunar cycle. We then experimentally increased the perceived predation risk by attracting grackles (Quiscalus mexicanus) to each half of the study site in two successive biweekly cycles. In each experimental cycle, crabs were significantly less likely to mate on the side with more birds. Moreover, on the side with elevated predation risk, the number of females leaving burrows to sample was greatly reduced relative to the number of females that surface-mated. Males waved less and built fewer mud pillars, which attract females, when birds were present. We discuss several plausible proximate explanations for these results and the effect of changes in predation regime on sexual selection.

Quantitative genetics of the dung fly Sepsis cynipsea: Cheverud's conjecture revisited

Full-sib heritabilities, phenotypic and genetic correlations of 10 morphological and three life history traits in the European dung fly Sepsis cynipsea are presented. We further supply a within-species test of Cheverud's (1988) conjecture that phenotypic correlations may be good, and much easier to obtain, substitutes for genetic correlations. Males were smaller in all traits except fore femur width. Heritabilities of morphological traits ranged from 0.33 to 0.90 and tended to be higher than the average reported for ectotherms (Mousseau & Roff, 1987). Those for the three female life history traits estimated were lower (0.16–0.32) and about average. Genetic correlations between the sexes ranged from 0.52 to 0.87 and were all less than unity. Differential selection on morphology in males and females can thus be expected to produce fast evolutionary responses in this species. Our analysis revealed also that in S. cynipsea phenotypic correlations are good substitutes for genetic correlations for combinations involving morphological traits, and that genetic correlations derived from the ANCOVA and the family mean methods were very similar. However, the former correspondence may be strongly reduced by the inclusion of particular traits (here male seta length).