Non-reproducing Females Research Articles

Olfactory guidance of nipple attachment and suckling in kittens of the domestic cat: Inborn and learned responses

In 60 kittens (11 litters) from free-ranging domestic cats we investigated the role of chemical cues in facilitating nipple attachment and suckling during the first month of postnatal life when kittens are totally dependent on the mother's milk. Kittens were tested both together and individually on sedated females in different reproductive states. We found (1) that newborn kittens with no suckling experience responded to the ventrum of lactating but not to the ventrum of nonlactating females with search behavior and attached to nipples within minutes; (2) that even in older kittens, nipple attachment depended on females' reproductive state, with virtually no attachments on nonreproducing females, some on pregnant females, the greatest number on early-lactating females, followed by a decline on late-lactating females; and (3) that kittens could locate their particular, most used nipple on their mother but not on a female of similar lactational age, even after eye opening. We suggest that kittens respond from birth with efficient nipple-search behavior to inborn olfactory cues on the mother's ventrum, that emission of these is under hormonal control, but that kittens also quickly learn olfactory cues specific to their own mother and to their own particular nipples.

Significant effects of Pgi genotype and body reserves on lifespan in the Glanville fritillary butterfly.

Individuals with a particular variant of the gene phosphoglucose isomerase (Pgi) have been shown to have superior dispersal capacity and fecundity in the Glanville fritillary butterfly (Melitaea cinxia), raising questions about the mechanisms that maintain polymorphism in this gene in the field. Here, we investigate how variation in the Pgi genotype affects female and male life history under controlled conditions. The most striking effect is the longer lifespan of genotypes with high dispersal capacity, especially in non-reproducing females. Butterflies use body reserves for somatic maintenance and reproduction, but different resources (in thorax versus abdomen) are used under dissimilar conditions, with some interactions with the Pgi genotype. These results indicate life-history trade-offs that involve resource allocation and genotypexenvironment interactions, and these trade-offs are likely to contribute to the maintenance of Pgi polymorphism in the natural populations.

Approaches to pregnancy diagnosis in the sable (Martes zibellina, Mustelidae, Carnivora) by noninvasive methods: Postimplantation period

To develop a reliable approach to pregnancy diagnosis in sables based on noninvasive methods of hormonal status assessment, the concentrations of immunoreactive compounds (IRC) binding with antibodies to progesterone have been measured in the feces of females at different stages of the reproductive cycle. The results show that this concentration is higher in truly pregnant than in mated but nonreproducing females. An increase in the IRC concentration relative to its individual baseline level may be regarded as a reliable indication of true pregnancy.

Analysis of fecal glucocorticoids in the North Atlantic right whale ( Eubalaena glacialis)

Very little is known about the endocrinology of the baleen whales. The highly endangered North Atlantic right whale (NARW; Eubalaena glacialis) is a good model species, because most NARW individuals are photo-identified with known histories. We used an 125I corticosterone assay, shown to reliably measure cortisol metabolites, to determine glucocorticoid metabolite concentrations in 177 NARW fecal samples collected between 1999–2004 in the Bay of Fundy, Canada. Fecal glucocorticoid metabolite concentrations varied significantly with sex and reproductive category, being highest in pregnant females (mean ±SE: 238.14 ± 74.37 ng/g) and mature males (71.6 ± 11.36), intermediate in lactating females (39.33 ± 5.82), and lower in non-reproducing females (23.11 ± 4.25) and immature males (34.33 ± 5.01) and females (14.0 ± 0.41). One case also suggests that glucocorticoids rise markedly in response to severe entanglement in fishing lines. Whales with fecal glucocorticoid content over 100 ng/g (termed “high-cort” samples) were rare, and included most pregnant females, some mature males, a fatally entangled whale, and several very young animals. Glucocorticoid concentrations were highly correlated with androgen concentrations in males and pregnant females. We analyzed the elution profiles of glucocorticoid and androgen metabolites in 13 samples with high-performance liquid chromatography (HPLC) to determine the extent to which androgen metabolites cross-react with our glucocorticoid assay. Males, pregnant females, non-pregnant females, and “high-cort” whales each had distinctly different immunoreactive HPLC profiles of glucocorticoid and androgen metabolites. A major glucocorticoid metabolite was prominent in all “high-cort” whales including the fatally entangled whale. The major fecal androgen was not testosterone but was instead a more nonpolar steroid (possibly dihydrotestosterone), which may be diagnostic of males. Androgen metabolites showed only minor cross-reactivity to our glucocorticoid assay, having a slight influence on glucocorticoid results in particular individuals. We conclude that fecal glucocorticoid analysis appears to be a useful measure of adrenal activity and reproductive condition for NARW.

The effect of long non-reproductive periods on the genital health in captive female white rhinoceroses ( Ceratotherium simum simum, C.s. cottoni)

White rhinoceroses suffer from a low reproductive rate in captivity. Intensive efforts to propagate specifically the northern white rhinoceros have been very limited. The dismal outlook for this subspecies in the wild makes successful ex situ breeding programs paramount. In this context, this study examined 48 southern and 6 northern white rhinoceroses using ultrasound and faecal hormone analysis to elucidate causes for female reproductive failure and to determine whether long non-reproductive periods have a detrimental impact on genital health. Results showed that 76% of the nulliparous females had intact hymenal membrane indicating these females had never been bred, at an age when their wild counterparts have delivered multiple offspring. Fifty-six percent of the studied population had various reproductive pathology. Cystic endometrial hyperplasia; leiomyomas of the cervix, uterus and ovary, adenoma; para-ovarian cysts and hydromucometra represent the scope of lesions identified. The stages of the lesions in nulliparous females correlated with age ( r = 0.4, P < 0.05). Due to the severity of the lesions, 28% of the study population was considered post-reproductive. Therefore, the reproductive life span in some individuals was 10–20 years shorter than expected. However, in parous females the incidence of pathological lesions was significantly lower ( P < 0.0001). Seventy-eight percent females studied had erratic or absent luteal activity. The hormone data corresponded with two ultrasonographic levels of ovarian activity, active and inactive, occurring within an age range of 3–19 years and 15–38 years, respectively. This suggests the lack of ovarian activity by reproductive mid-life in non-reproducing females. The accuracy of the ultrasound findings was validated by necropsy in nine animals showing a strong positive correlation ( r 2 = 0.9, p < 0.001). Our data suggests that the development of reproductive pathology and ovarian inactivity in white rhinoceros is an age-related consequence of long non-reproductive periods. This asymmetric ageing process of the genital organs can be prevented with the achievement of at least one pregnancy.

WATER BUDGET DURING REPRODUCTION IN FEMALE COMMON SPINY MICE (ACOMYS CAHIRINUS)

We determined water budget in the reproducing female common spiny mouse (Acomys cahirinus) offered ad libitum millet seeds and water. We hypothesized that the proportional increase in water input in lactating mice compared with nonreproducing mice would be greater than the proportional increase in energy intake, given that more water would be required for higher heat production and for milk production. Females gave birth to 1 or 2 offspring; results of water budget and energy intake did not differ among litter sizes and were combined. Lactating females increased water input and energy intake by 59.1% and 35.2%, respectively, compared with nonreproducing females, confirming our hypothesis. Milk production (1.04 ml/day) accounted for 29% of the difference in water output between lactating and nonreproducing spiny mice.

Gonad development and plasma steroid profiles by HRGC/HRMS during one reproductive cycle in reference and leachate-exposed female perch ( Perca fluviatilis)

Endocrine processes were studied in reference female perch ( Perca fluviatilis) from Lake Djursjön and in leachate-exposed females from Lake Molnbyggen during one reproductive cycle. A high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) technique enabled the analysis of circulating sex steroids [progesterone (P), 17α-hydroxyprogesterone (17α-OHP), androstenedione (A), testosterone (T), estrone (E1), and 17β-estradiol (E2)], the maturation-inducing hormone (MIH) 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-P), and glucocorticoids [11-deoxycortisol (11-DC) and cortisol]. Body and organ measurements, ratio of sexually mature (SM) females, and frequencies of body lesions, were also recorded. High frequencies of body lesions and a low ratio of SM females were generally found in Molnbyggen. These females also had lower gonadosomatic index (GSI) and liver-somatic index (LSI) in the early stages of vitellogenesis, indicating either a delayed onset of oogenesis or an impaired vitellogenesis. Non-reproducing females from both lakes showed a similar LSI cycle as SM females. Increasing T and A levels in SM females from Djursjön coincided with the GSI peak at the time of spawning. These two androgens were on several occasions lower in SM females from Molnbyggen, possibly the result of a disrupted 17,20-lyase activity of the P450 17α enzyme because only minor effects were observed on circulating P and 17α-OHP levels. E2 and E1 levels increased during vitellogenesis in females from both lakes, with E1 levels more closely resembling the peaks of A and GSI. Peak levels of 17α,20β-P at the time of spawning confirmed its function as the MIH in perch, while the simultaneous peak of 11-DC suggests that it also may be involved in final maturation of the oocytes.

Differential grazing of female and male plants of prostrate juniper (Juniperus communisL.)

Summary Females and males of dioecious species may not allocate the same proportions of assimilate to plant protection and so may be differentially grazed. The distribution range of the dioecious, coniferous shrub, juniper (Juniperus communis) is declining in the UK and populations are becoming fragmented. The main aims of this study were to (i) assess the sex structure of populations of prostrate juniper at four sites in northern Scotland and (ii) assess the extent of grazing on individual plants. A total of 518 prostrate juniper plants were inspected in the four populations. The sex of 30–85 % of them could not be determined. There were differences between the sites in grazing intensity, plant density, plant size, and the proportion of females. Between June and September, there was almost no grazing of current growth and no difference between males and females in the amount of grazing. Most grazing took place over winter. This was supported by the observation that dung counts over summer did not correlate with grazing of current or old shoots. Female, male and unsexable plants had similar size ranges. Female and unsexable plants had similar numbers and proportions of old shoots grazed but male plants had significantly less. This suggests that many of the unsexable plants were non-reproducing females and that the greater grazing on unsexable plants might be responsible for the cessation of reproduction. The impact of differential winter grazing of prostrate female and male juniper plants is discussed in relation to the conservation of this species in Scotland and the UK.

The link between sexual dimorphism, activity budgets, and group cohesion: the case of the plains zebra (Equus burchelli)

Animals that differ in reproductive status and body size have different needs in terms of foraging and resting. In most social ungulates this leads to sexual segregation, probably because of incompatibilities between the activity budgets of males and females. Since most studies on behavioural differences between the sexes have been done on sexually dimorphic species, we decided to look at a system in which males and females are similar in body size. We studied time budgets, synchrony of behaviour, and bite rates of plains zebras (Equus burchelli) to evaluate the factors that enable these extremely social ungulates to stay in stable mixed-sex family groups throughout the year. As we predicted, time budgets were similar among males, lactating females, pregnant females, and non-reproductive females. Furthermore, we observed close synchronization of behaviours between females that differed in reproductive status and males. Lactating females, however, did take more bites per minute when foraging than either pregnant or non-reproducing females or males. We assume that the higher bite rates of lactating females were due to the extra costs of producing milk for their foal. We concluded that the special harem mating system, and for females the year-round possibility of conceiving, force the animals to synchronize their time budgets, which might be a major reason for the lack of difference in body size between males and females.

ENERGY REQUIREMENTS DURING REPRODUCTION IN FEMALE COMMON SPINY MICE (ACOMYS CAHIRINUS)

We hypothesized that energy intake of lactating females is the main factor determining growth of the young and that use of maternal energy reserves is less important when food is available in abundance. We studied reproducing female common spiny mouse (Acomys cahirinus) offered millet seeds and water ad libitum. Females gave birth to 1 or 2 young, and growth rate was similar between litters of 1 infant and 2 infants combined. In addition, energy intake of the 2 groups of females was similar. Lactating females increased energy intake by 45% (per g0.75) over that of nonreproducing females. Energy intake and change in body mass of the lactating female each explained about 50% of the variance in infant growth and, therefore, our hypothesis was not supported. Energy intake and change in body mass of the lactating female together explained approximately 76% of the variance in growth of young.

Mortality in relation to season, age, sex, and reproduction in Columbian ground squirrels (Spermophilus columbianus)

We investigated the timing of and age at mortality in Columbian ground squirrels (Spermophilus columbianus) in relation to sex and reproductive status. Life-history data were collected from 1994 to 1999 in the foothills of the Rocky Mountains, Alberta, Canada. We predicted increased mortality for males during mating and for females during lactation. Further, we expected reproductively successful females to have higher mortality than females that did not reproduce successfully. Finally we assumed that at some age reproductive success of females would decrease and mortality increase because of old age. For both sexes, survival over winter was high (ca. 90%) for adults. While there was a significant increase in mortality of adult males during the mating season, females did not have higher mortality during lactation than during the rest of the active season. Reproductive status influenced mortality in females: non-reproducing females had a higher chance of surviving than reproducing females. Females that weaned young were more likely to die after the weaning period than females that lost their litter during lactation. There was a positive correlation between maternal survival and survival of offspring to yearling age. Our results showed evidence of trade-offs between reproduction and survival of male and female Columbian ground squirrels.

Changes in Plasma Progesterone in Relation to Vitellogenesis and Gestation in the Viviparous Snake Vipera aspis

Viviparity has arisen from oviparity on more than 100 independent occasions in squamate reptiles, providing an unique opportunity to investigate the ways in which endocrine control of gestation length has been modified by natural selection during this major transition in reproductive modes. Intuitively, the evolution of viviparity might be expected to involve an increasingly important role for the steroid hormone progesterone, rather than estradiol. Unfortunately, published data on this topic in snakes are scarce and often contradictory. Females of the viviparous snake Vipera aspis reproduce with a lower than annual frequency, providing the opportunity to examine steroid profiles simultaneously in vitellogenic, pregnant, and postparturient versus nonreproductive females. From 1990 to 1994, more than 500 blood samples were collected from more than 100 females. Progesterone, estradiol-17β, and several plasma metabolites were assayed by radioimmunoassay and spectrophotometry. In contrast to earlier studies, we found significant differences between plasma progesterone levels in reproducing (10.5 ± 9.1 ng ml−1, N = 168) and nonreproducing (5.1 ± 4.2 ng ml−1, N = 121) females. Estradiol reached high levels during vitellogenesis (4.8 ± 4.0 ng ml−1, N = 16), and progesterone levels increased during gestation (from 3.7 ng ml−1 before gestation to 18.7 ng ml−1 at midgestation). However, experimental elevation of plasma progesterone levels with implants (up to 44.4 ng ml−1) did not modify plasma metabolite levels or delay parturition.

The scheduling of spawning with the moult cycle in Northern krill (Crustacea: Euphausiacea): a strategy for allocating lipids to reproduction

Summary Euphausiids moult and grow throughout their life, which implies sharing of resources between growth and reproduction for adult krill. In the Northern krill, Meganyctiphanes norvegica (M. Sars), female krill produce eggs cyclically. Spawning moult cycles alternate with vitellogenic moult cycles for lipid yolk accumulation. Histology shows that lipids are associated with the R cells of the digestive gland in both sexes, with the yolk platelets of mature oocytes and with the fat body cell membranes and blood lacunae in reproducing females. Mature female krill can have a total lipid content twice as high as males, mostly due to accumulation in the ovary, the fat body and the haemolymph. In contrast, in males, as well as in non-reproducing females, the highest percentage of lipids is found in the digestive gland and the haemolymph. In Meganyctiphanes norvegica, the most abundant lipid fractions are polar lipids and triglycerides, the latter being relatively low in reproducing female gonad and fat body. Triglycerides are believed to be a pure energy source and polar lipids are essential for membrane development in embryos. The fatty acid content and composition of the triglyceride and polar lipid fractions in females are different from males, related to both reproductive and dietary processes. Higher levels of polyunsaturated fatty acids (PUFA) in the polar lipid fraction were found in reproductive females. During the non-reproductive season, the converse was found, indicating the specific role PUFA and other fatty acids play in growth and egg production. Adaptive processes linked to reproduction were studied comparatively in three populations of the Northern krill—Clyde Sea (W, Scotland), Kattegat (E, Denmark), Ligurian Sea (Mediterranean)—all differing considerably in climatic and trophic conditions. Such adjustments in lipid synthesis and storage are viewed as reproductive strategies developed by the Northern krill in response to different environmental conditions.

Increased Parasite Abundance Associated with Reproductive Maturity of the Clam Anodonta piscinalis

Several studies on vertebrates have demonstrated that reproductive activities may increase the parasite load, but this has not been shown in invertebrate hosts. We studied abundance of a potentially harmful gill parasite, the ergasilid copepod Paraergasilus rylovi, from the freshwater bivalve host Anodonta piscinalis in relation to reproductive maturity of the host in the field. Prevalence of this previously unstudied parasite varied from 90 to 100%, and the mean parasite abundance from 16.3 to 28.8 among 3 study populations. Abundance of P. rylovi increased with host size. In the maturating age groups (3-5 yr) the length-adjusted mean parasite abundance among mature, reproducing female clams that brooded glochidia larvae was 2 times higher than in nonreproducing females, the observed pattern being consistent among the 3 study lakes. Alternative, mutually nonexclusive explanations may be found for the result. For example, changes in clam behavior or filtration activity accompanying maturation can increase host exposure to parasites, or reproduction may decrease energy available to host immunologic defense. However, the present result indicates that maturation, and reproduction, is associated with increased parasite abundance in A. piscinalis, an invertebrate host.

Costs of reproduction in female moose (Alces alces) as measured by means of phenotypic correlations

The costs of pregnancy and lactation in terms of subsequent body growth and fecundity were studied by comparing different reproductive categories of Swedish female moose (Alces alces) during 1989-1992. Non-reproducing females and females that experienced gestation but not lactation were significantly heavier than females in the same reproductive category prior to reproduction. Production of one offspring and subsequent lactation during the summer and early autumn were also associated with an average annual increase in carcass mass, although this was less pronounced than in females that only experienced gestation. By contrast, production of two offspring and successful rearing of both to the autumn resulted, on average, in a reduction of carcass mass (7%) relative to that of females in the same reproductive category prior to reproduction. In female moose, while body growth was affected by the costs of lactation, future fecundity was not. Instead, future fecundity was related most strongly to the number of offspring produced during the current year. This positive association could not be attributed to variation in individual quality in terms of age or carcass mass. The ultimate consequences of reproduction in female moose seem to strongly influence the patterns of growth: adult females will alternate between gain and loss of body mass among years, depending on the number of offspring produced and successfully reared through the lactation phase.

Costs of Reproduction in Water Skinks

Cost of reproduction measured under laboratory conditions may have little bearing on actual cost observed in the field, because both environmental conditions and behavior can modify the manifestation of these costs. I studied survival, growth, and reproduction in a wild population of southern water skinks (Eulamprus tympanum) over 3 yr to measure costs of reproduction in females, to examine how the environment influences these costs, and to assess the extent to which females are able to reduce costs. The proportion of mature females that reproduced each year varied from 30—60%. Frequent reproduction appeared costly in terms of both survival rates and growth. Growth rates and survival rates were negatively correlated with reproduction during the 3—yr study. In the coolest and wettest year of the study, when food intake by females was relatively low, gravid females and females that had reproduced in the previous years survived well than nonproducing females. There was no evidence of a survival cost of reproduction in the other two years of the study. Reproduction also imposed a fecundity cost, as overall, mean growth rates of reproducing females were reduced relative to those of nonreproducing females of the same body size. Reduced growth rate translates to reduced litter size in these skinks, because fecundity increases with body size. These results suggest that reproduction can be costly in terms of both survival and future reproduction in these skinks, but that survival costs are not consistent from year to year and are mediated by environmental conditions. Females appear to adjust their frequency of reproduction to minimize these costs, as those females that skipped opportunities for reproduction were those expected to gain the greatest growth and fecundity benefit by skipping.

Changes in Plasma T4 and T3 Levels during Reconditioning and Rematuration in Male and Female Wild Atlantic Salmon (Salmo salar) Kelts Held in Freshwater under Two Photoperiod Regimes

The plasma level of L-thyroxine (T4) of wild reconditioned Atlantic salmon (Salmo salar) kelts held in freshwater at seasonal temperatures on a natural simulated photoperiod showed a robust seasonal profile with a marked peak in early spring followed by low levels throughout the summer. Plasma T4 was low in kelts that did not recondition and was uninfluenced by gender, eventual reproductive state, or imposition of a 6-mo compressed photocycle. The plasma 3,5,3′-triiodo-L-thyronine (T3) level also rose in spring in both males and females. In males and nonreproducing females, plasma T3 remained high during the growth phase in summer and decreased in fall and winter. Plasma T3 was very low in nonfeeding fish and showed some influence by the 6-mo compressed photocycle. Plasma T3 was particularly low in females at the time of vitellogenesis when 17β-estradiol was high. It is concluded that in reconditioned Atlantic salmon kelts, levels of plasma T4 and T3 appear to be controlled independently and that plasma T3 is more susceptible than T4 to vitellogenic state and other factors relating to metabolic demands.

Fat cycling in the mosquitofish (Gambusia affinis): fat storage as a reproductive adaptation.

We argue, based on reviewed literature covering reptiles, amphibians, birds, and fish, that fat storage may represent a life history adaptation because it enables an organism to shift in time when resources are allocated to reproduction. We applied these arguments to fat and population cycles in three populations of the mosquito fish, Gambusia affinis. For males, there appeared to be a constant size at maturation during the reproductive season. Mature males became scarce late in the summer. At the same time, immature males delayed maturity and attained much larger sizes; they matured in large numbers in the fall. The amount of stored fat tended to be equal for immature and mature males at all times except in the late summer. In the August samples, when mature males were relatively rare, they also had the lowest level of fat reserves. It appears that the older generation of mature males did not store fat and did not overwinter. At the same time, immature males registered a two to three fold increase in fat reserves. These differences in fat content between mature and immature males disappeared by September, probably because of the recruitment of a new generation of mature males. The reserves were gradually utilized during the winter. Females reproduced from the late spring through mid- to late-summer. They stopped reproducing in the late summer, when there was ample time to produce an additional litter of young. There was an inverse relationship between resources devoted to reproduction and fat reserves. As reproductive allotment decreased in the late summer, fat reserves increased. The magnitude of the change in fat reserves was similar to that displayed by males. The reserves were depleted over the winter. Significant reserves remained at the beginning of the reproductive season the following spring. Reproducing females utilized the remaining reserves significantly more rapidly than non-reproducing females. An analysis of resource availability revealed an overall decrease in food availability in the late summer, coincident with the increase in fat reserves. These cycles are therefore not attributable to changes in resource availability. They instead indicate a change in how resources are allocated by the fish. The trends in the data indicate that fat reserves are used to shift investment in reproduction from the late summer to the following spring. In males, deferring maturity, rather than maturing in August, allows them to store the necessary reserves to survive the winter so that they can mate the following spring. In females, a subset of the fat reserves is intended for producing the first clutch of eggs the following spring. The female pattern corresponds to those reported for a diversity of organisms. The possible advantages of shifting reproductive effort from the fall to the following spring include higher fecundity and higher offspring fitness. The limitations of the methodology and potential directions for future research are discussed.

Energy costs of reproduction in the djungarian hamster Phodopus sungorus under laboratory and seminatural conditions.

The aim of this study was to obtain ecologically relevant data on the rates and efficiencies of energy allocation to reproduction and to determine how laboratory data compare with data obtained under 'seminatural' conditions. Using the tritiated water (HTO) method we measured average daily metabolic rates (ADMRs) in Phodopus sungorus reproducing females over the whole period of pregnancy and lactation and in nonreproducing ones, under both laboratory and 'seminatural' conditions.Taking the difference in total energy expenditure between reproducing and nonreproducing females as the additional energy requirement for reproduction, it was found that the absolute energy expenditure for reproduction was independent of the experimental conditions used. For the production and nursing of one litter, Djungarian hamsters metabolized an additional 20.9 MJ kg-1 in the laboratory, i.e. a 37% increase over normal maintenance expenditure, and 22.6 MJ kg-1 under seminatural conditions, i.e. a 24% increase. The efficiency of litter production was estimated as 18.3% in the laboratory and as 16.4% under seminatural conditions. The differences between the two experimental conditions were not significant.

Predation versus resource limitation in survival of adult burrowing wolf spiders (Araneae: Lycosidae).

The influences of food supply and density on adult survival were examined in the burrowing wolf spider Geolycosa rafaelana (Lycosidae), using manipulations of spider populations on eight 400 sq m experimental plots. A total of 110 adult spiders were captured, weighed, marked, and returned to their burrows during April-May 1983. Treatments of (1) food supplementation, (2) density reduction, (3) food supplementation combined with density reduction, and (4) no manipulation (control) were applied to the eight populations, and adult survival and reproduction were monitored during May-October 1983. Survival rates were higher for nonreproducing adult female populations with reduced density, and lower for nonreproducing females in populations with food supplementation. A pompilid wasp, Paracyphononyx funereus, was documented as a parasitoid of G. rafaelana, producing 50%-65% mortality in adult females during winter, and 4-5% mortality in adult females during summer. The observed survival responses were correlated with variations in predation, while parasitism did not appear to be strongly density-dependent.