Larval and early juvenile development of Lithodes santolla (Molina, 1782) (Decapoda: Anomura: Lithodidae) reared at different temperatures in the laboratory

The southern king crab, Lithodes santolla Molina, is distributed in cold-temperate and subantarctic waters ranging from the southeastern Pacific island of Chiloé (Chile) and the deep Atlantic waters off Uruguay, south to the Beagle Channel (Tierra del Fuego, Argentina/Chile). Recent investigations have shown that its complete larval development from hatching to metamorphosis, comprising three zoeal stages and a megalopa, is fully lecithotrophic, i.e. independent of food. In the present study, larvae were individually reared in the laboratory at seven constant temperatures ranging from 1 to 18 °C, and rates of survival and development through successive larval and early juvenile stages were monitored throughout a period of 1 year. The highest temperature (18 °C) caused complete mortality within 1 week; only a single individual moulted under this condition, 2 days after hatching, to the second zoeal stage, while all other larvae died later in the zoea I stage. At the coldest condition (1 °C), 71% of the larvae reached the zoea III stage, but none of these moulted successfully to a megalopa. A temperature of 3 °C allowed for some survival to the megalopa stage (17-33% in larvae obtained from two different females), but only a single individual passed successfully, 129 days after hatching, through metamorphosis to the first juvenile crab instar. At all other experimental conditions (6, 9, 12 and 15 °C), survival through metamorphosis varied among temperatures and two hatches from 29% to 90% without showing a consistent trend. The time of nonfeeding development from hatching to metamorphosis lasted, on average, from 19 days at 15 °C to 65 days at 6 °C. The relationship between the time of development through individual larval or juvenile stages (D) and temperature (T) was described as a power function (D=aT^b, or log[D]=log[a]blog[T]). The same model was also used to describe the temperature dependence of cumulative periods of development from hatching to later larval or juvenile stages. One year after hatching, the 7th (6 °C) to 9th (15 °C) crab instar was reached. Under natural temperature conditions in the region of origin of our material (Beagle Channel, Argentina), L. santolla should reach metamorphosis in October-December, i.e. ca. 2 months after hatching (taking place in winter and early spring). Within 1 year from hatching, the crabs should grow approximately to juvenile instars VII-VIII. Our results indicate that the early life-history stages of L. santolla tolerate moderate cold stress as well as planktonic food-limitation in winter, implying that this species is well adapted to subantarctic environments with low temperatures and a short seasonal plankton production.     

Larval development of the subantarctic squat lobster Munida subrugosa (White, 1847) (Anomura: Galatheidae), reared in the laboratory

The larval development of the squat lobster Munida subrugosa from subantarctic waters of the Beagle Channel (Tierra del Fuego, Argentina) was studied under controlled laboratory conditions of temperature, salinity, and food supply. Developmental times, survival, and growth of larvae and early juveniles were investigated. Hatching of the entire brood always occurred during one night. Larvae were kept in 100ml individual bowls with filtered seawater at 8 ± 0.5°C and fed with Artemia spp. nauplii three times a week. Larvae passed through 6 zoeal instars and one megalopa. Previously, only five zoeal instars were known from this species. Mean cumulative durations of the zoeal stages I to VI were: 20.5 ± 2.5, 33.9 ± 4.1, 43.3 ± 5.4, 52.6 ± 5, 61.2 ± 3.9, and 83days, respectively. By adding the 28days that a single megalopa took to metamorphose to crab I stage, the complete larval development lasted 111days. Highest mortality occurred prior to the moult from the zoea I to zoea II stage (79.21% ± 18.65%) and during the moult from zoea VI to megalopa (92.86%). Carapace length was 1.64 ± 0.06, 1.52 ± 0.16, 1.57 ± 0.26, 1.64 ± 0.21, 2.11 ± 0.35, and 2.58 ± 0.19mm, for zoeal stages I to VI, respectively. Carapace length of megalopae and crab I instars was similar (2.85 ± 0.28 and the 2.84 ± 0.05, respectively). Unlike other subantarctic decapods, which show a tendency towards abbreviated larval development and/or some degree of endotrophy, M. subrugosa shows an extended planktotrophic larval development synchronized with short seasonal plankton production in austral summers.     

Changes in biomass and chemical composition during lecithotrophic larval development of the southern king crab, Lithodes santolla (Molina)

Changes in biomass and elemental composition (dry mass, W; carbon, C; nitrogen, N; hydrogen, H) were studied in the laboratory during complete larval and early juvenile development of the southern king crab, Lithodes santolla (Molina), formerly known as Lithodes antarcticus (Jacquinot). At 6±0.5 °C, total larval development from hatching to metamorphosis lasted about 10 weeks, comprising three demersal zoeal stages and a benthic megalopa, with mean stage durations of 4, 7, 11 and 47 days, respectively. No differences in development duration or mortality were observed in larvae either fed with Artemia sp. nauplii or unfed, indicating that all larval stages of L. santolla are lecithotrophic. First feeding and growth were consistently observed immediately after metamorphosis to the first juvenile crab stage. Regardless of the presence or absence of food, W, C, N and H decreased throughout larval development. Also the C:N mass ratio decreased significantly, from 7.7 at hatching to 4.1 at metamorphosis, indicating that a large initial lipid store remaining from the egg yolk was gradually utilized as an internal energy source, while proteins played a minor role as a metabolic substrate. In total, 56-58% of the initial quantities of C and H present at hatching, and 20% of N were lost during nonfeeding larval development to metamorphosis. Nine to ten percent of the initially present C, N and H were lost with larval exuviae, half of these losses occurring in the three zoeal stages combined and another half in the megalopa stage alone. Metabolic biomass degradation accounted for losses of about 47-50% in C and H but for only 10% in N. Hence, most of the losses in C and H reflected metabolic energy consumption (primarily lipid degradation), while about half of the losses in N and two thirds of those in W were due to larval exuviation. Complete independence from food throughout larval development is based on an enhanced maternal energy investment per offspring and on energy-saving mechanisms such as low larval locomotory activity and low exuvial losses. These traits are interpreted as bioenergetic adaptations to food-limited conditions in Subantarctic regions, where a pronounced seasonality of day length limits the period of primary production, while low temperatures enforce a long duration of pelagic development.     

Changes in biomass, lipid, fatty acid and elemental composition during the abbreviated larval development of the subantarctic shrimp Campylonotus vagans

Ontogenetic changes in biomass and chemical composition were studied in the laboratory during the abbreviated larval and early juvenile development of the caridean shrimp Campylonotus vagans from the subantarctic Beagle Channel, Argentina. At 7±0.5 °C, development from hatching to metamorphosis took about 44 days. The larvae started feeding on Artemia nauplii immediately after hatching, although larval resistance to starvation was high (average 18 days, maximum 29 days). Dry mass (DM), carbon (C), nitrogen (N) and hydrogen (H) contents increased about a fourfold from hatching to metamorphosis, while the C:N mass ratio increased from about 3.7 to 4.3. The protein and total lipid contents increased gradually from hatching to the first juvenile stage, the former from 190 to 640 μg/individual, the latter from 37 to 95 μg/individual. The lipid mass fraction was low throughout larval development (3-9% of DM), while the protein content was much higher and almost constant (30-40%). The dominating fatty acids were 18:1(n-9), 16:0, 20:5(n-3), 18:1(n-7), 18:3(n-3), 18:0, 16:1(n-7). Except for 20:5(n-3), these resulted mainly from food uptake (Artemia nauplii). Exuvial losses of C, H and N (all larval stages combined) accounted for only 7%, 1% and 1% of the initial values at hatching. In contrast, 37% of initial DM was lost. Partially food-independent (endotrophic) larval development is discussed as an adaptation to food scarcity at high latitudes, while the abbreviated planktotrophic larval development appears to be synchronised with seasonal peaks in primary production, allowing for an optimal resource exploitation in a food-limited environment.     

Insecticidal Properties of Bistrifluron,Benzoylphenylurea Insecticide,against Cotton Caterpillar,Palpita indica (Lepidoptera: Pyralidae)

In this study, we assessed the insecticidal properties of bistrifluron on the insect life stages of the cotton caterpillar, Palpita indicaa, with the primary emphasis on hatching rate, mortality, and susceptibility to chemicals, in addition to the preoviposition period, longevity, and fecundity. Bistrifluron exerted no effects on the egg. However, the larvae hatching from the eggs evidenced 100% mortality within 24 hrs. The susceptibility of P. indica to bistrifluron evidenced similar results at each larval stage. When bistrifluron was applied to the pupal stage, the chemicals significantly affected the longevity and fecundity of the normally emerging adults. The application of high concentrations of bistrifluron (50 ppm) to young adults delayed their pre-oviposition periods. In addition, the longevity, fecundity and hatching rate were attenuated.     

Effects of egg size reduction and larval feeding on juvenile quality for a species with facultative-feeding development

In free-spawning marine invertebrates, larval development typically proceeds by one of two modes: planktotrophy (obligate larval feeding) from small eggs or lecithotrophy (obligate non-feeding) from relatively large eggs. In a rare third developmental mode, facultative planktotrophy, larvae can feed, but do not require particulate food to complete metamorphosis. Facultative planktotrophy is thought to be an intermediate condition that results from an evolutionary increase in energy content in the small eggs of a planktotrophic ancestor. We tested whether an experimental reduction in egg size is sufficient to restore obligate planktotrophy from facultative planktotrophy and whether the two sources of larval nutrition (feeding and energy in the egg) differentially influence larval survival and juvenile quality. We predicted, based on its large egg size, that a reduction in egg size in the echinoid echinoderm Clypeaster rosaceus would affect juvenile size but not time to metamorphosis. We reduced the effective size of whole (W) zygotes by separating blastomeres at the two- or four-cell stages to create half- (H) or quarter-size (Q) “zygotes” and reared larvae to metamorphosis, both with and without particulate food. Larvae metamorphosed at approximately the same time regardless of food or egg size treatment. In contrast, juveniles that developed from W zygotes were significantly larger, had higher organic content and had longer and more numerous spines than juveniles from H or Q zygotes. Larvae from W, H and Q zygotes were able to reach metamorphosis without feeding, suggesting that the evolution of facultative planktotrophy in C. rosaceus was accompanied by more than a simple increase in egg size. In addition, our results suggest that resources lost by halving egg size have a larger effect on larval survival and juvenile quality than those lost by withholding particulate food.     

Embryonic and larval development of a Japanese spinous loach,Cobitis takatsuensis

The embryonic and larval development ofCobitis takatsuensis, a mountain stream spinous loach, was surveyed by incubating artificially inseminated eggs. The mean diameter of the inflated eggs and mean total length of newly-hatched larvae were 2.7 mm and 5.7 mm, respectively. The eggs were spherical, transparent and unpigmented, with a pale yellow yolk and no oil globule. The daily cumulative temperature to hatching was estimated to be 70–110°C. day. Hatched larvae were unpigmented with outer gill filaments on their cheeks, as in otherCobitis species, but the melanophores were comparatively less obvious at each developmental stage. The larvae started feeding eleven days after hatching yolk absorption being completed sixteen days after hatching. All the fin rays were fully developed and the juvenile stage reached at 16 mm TL, 38 days after hatching. Embryonic and larval developmental traits ofC. takatsuensis, such as egg size, clutch size and larval pigmentation, were similar to the Korean species,Niwaella multifasciata, that lives in the upper reaches of the Nak-tong river, andN. delicata, which inhabits Japanese mountain streams, rather than to its congeners. Among cobitine fishes, the spawning of a small number of larger eggs yielding larger larvae without pigmentation, characteristics shared byC. takatsuensis, N. multifasciata andN. delicata, is attributable to adaptation to cold mountain streams.     

Seasonal life cycle and autogeny in the mosquitoAedes togoi in northern Kyushu,Japan, with experimental analysis of the effects of temperature,photoperiod and food on life-history traits

We studied seasonal changes in the larval population structure, adult size, and autogeny (egg production without a bloodmeal) of the mosquitoAedes togoi on the seacoast of northern Kyushu, Japan. The effects of temperature, photoperiod and food conditions on larval development, adult size and autogeny were studied in the laboratory.Aedes togoi overwintered in both the egg and larval stages and was multivoltine. Adult size was greater in spring and autumn and smaller in summer. Autogeny occurred in spring and autumn but not in summer. Autogenous females were larger than anautogenous females, and larger autogenous females produced more eggs. Laboratory experiments showed that autogeny was promoted under low temperature and short-day conditions which corresponded with spring/autumn conditions in the field. Experimental food limitation in the larval stage greatly reduced adult size and autogenous egg production. In the field, large inter-pool variations in adult size and autogeny rate probably resulted from variations in nutrient and crowding conditions. Seasonal autogeny ofAedes togoi was discussed in terms of life-history strategy under fluctuating environmental conditions where relative advantages of autogenous and anautogenous reproduction alternate seasonally.     

FITNESS CONSEQUENCES OF VARIATION IN EGG SIZE AND FOOD ABUNDANCE IN BROOK TROUT SALVELINUS FONTINALIS

Relationships between egg size and juvenile survival in brook trout, Salvelinus fontinalis, were determined experimentally at two levels of food abundance and then incorporated into a model that related maternal fitness to egg size and food supply. Egg volume was positively correlated with juvenile size at hatching and size at yolk sac resorption but had no significant effect on embryonic survival or development time. Juvenile survival was linearly related to egg size throughout the first 50 days of exogenous feeding at high and low food levels. The effects of egg size and food abundance on juvenile survival were not additive. Decreased food abundance significantly increased mortality among the smallest eggs but had a negligible effect on the largest eggs. Model simulations indicate that maternal fitness is a curvilinear function of egg size and that food supply influences both the height and the shape of the function. The fitness functions provide empirical support for the hypothesis that selection favors an increase in offspring size with reductions in resource abundance.     

萧氏松茎象的生活史、产卵和取食习性

萧氏松茎象Hylobitelus xiaoi是严重蛀害国外松的新害虫。在江西赣南地区两年发生一代,以幼虫在蛀道、成虫在蛹室或土中越冬。卵和蛹的发育起点温度分别为8.4℃和7.5℃,有效积温分别为215.9和345.3日·度。各虫态历期：13～28℃间,卵为52.9～11.4天;13～30℃间,蛹为60.1～16.4天; 25℃恒温下,幼虫128.9天。成虫靠爬行活动,极少飞翔。成虫具夜出性活动节律：即傍晚上树行取食、交配和扩散等活动,早晨回到树干基部或土缝中。成虫需取食松枝作为补充营养,产卵前期46.3天,产卵期 105.3天,卵产于近表土的寄主树皮内,每雌产卵35.7粒。幼虫5～7龄,以幼树危害最烈。     

The reproductive success of pike, Esox lucius: aspects of fecundity, egg density and survival

Power-law relationships have been estimated between fecundity and fish length, weight and age for pike from two gravel pit lakes (Main Lake and St Peter's Lake) in Buckinghamshire, England. Relative fecundity, estimated at 17.6 eggs g⁻¹ for Main Lake pike and 19.4 g⁻¹ for St Peter's Lake pike, did not differ significantly between the lakes. Population fecundity for the Main Lake was estimated at 10.6 million eggs and 6.4 million eggs in 1986 and 1987, respectively.
Experimental work involving samples of eggs from 18 artificially fertilized Main Lake female pike showed a significant relationship between egg diameter and female length, and a significant difference between mean egg diameters for 41-cm and 101-cm females. No significant relationships were found between mean egg size and mean fry size, nor between fry length and adult length. Mean size differences between newly hatched, 18-day-old and 41-day-old fry from the 41-cm and 101-cm females were not significant.
Samples of eggs taken at 2-day intervals from 6 April to 5 May in a pike spawning area of the Main Lake revealed clumped distributions of eggs, with average egg densities ranging from 1 to 47 eggs per 0.071 m² (14–671 m ²) on sand and silt substrata. The maximum egg density of 51 per 0.071 m² (729 m⁻²) was found on flooded grass. The stages of development of the eggs were identified over the sampling period. Survival from stage 1 to fry was estimated at 3–6%. Egg losses were estimated at 9–10% day⁻¹.
Egg survival experiments gave overall hatching success rates of 11 % on sand/silt compared with 2.5% on aquatic plants (1986), and 18.9% on undisturbed sand/silt compared with 7.9% on disturbed sand/silt (1987). The effect of siltation on egg hatching is discussed.     

Development ofDiatraea Saccharalis [Lep.: Pyralidae] at constant temperatures

At constant temperatures between 15.6 and 32°C the incubation time of eggs ofDiatraea saccharalis (F.) was reduced by each increase in temperature. At 34°C the time decreased. Highest (98.6%) and lowest (9.9%) egg hatch occurred at 26 and 34°C, respectively. Larvae completed development at temperatures ranging from 22 to 34°C; however, only 4.4% of the larvae pupated at 34°C. Duration of the larval stage at 30°C (♂=18.1 days; ♀=19.1 days) was ca. 14 days shorter than at 22°C. Maximum rate of development in the pupal stage occurred at 28°C (ca. 6.8 days), and a higher temperature increased developmental time and mortality. Adult longevity and egg production generally were reduced with increasing temperatures and egg production was highest at 24°C (729.8 eggs/ moth). As many as 7 larval stages occurred; but most larvae completed development in 5 stages, and none completed development in less than 5 stages. The female larval stage was ca. 1 day longer than that of males, and this difference occurred primarily in the 5th stage.     

柑桔爆皮虫卵巢发育动态

本研究利用室内饲养成虫,对柑桔爆皮虫的蛹及正常取食和交配、正常取食但未交配以及正常交配但未取食三种处理的雌成虫的卵巢发育进行了系统观察。结果显示：该虫具有1对卵巢,每侧有5根卵巢管。前两种处理的雌虫卵巢管均能正常发育,成虫寿命在30天左右; 没有取食的雌虫寿命只有7天左右,在其卵巢管的生长区和成熟区均无卵形成。根据卵巢的形状、卵的产生过程、卵巢萼内有无卵粒以及卵黄沉积情况等将卵巢发育程度分为6个级别,即发育初期（0级）、卵黄沉积前期(Ⅰ级)、卵黄沉积期(Ⅱ级)、成熟待产期(Ⅲ级)、产卵盛期(Ⅳ级)和产卵末期(Ⅴ级)。每头雌虫最高怀卵量在140粒左右,根据雌虫怀卵量变化趋势,推测正常取食和交配的柑桔爆皮虫雌虫在出孔后10天左右开始产卵,产卵历期可达22天左右。据此提出该虫卵巢管发育到成熟待产期(Ⅲ级)之前（即羽化出孔后10天之内）为出孔成虫的防治适期。     

Carryover effects of predation risk on postembryonic life-history stages in a freshwater shrimp

For organisms with complex life histories it is well known that risk experienced early in life, as embryos or larvae, may have effects throughout the life cycle. Although carryover effects have been well documented in invertebrates with different levels of parental care, there are few examples of predator-induced responses in externally brooded embryos. Here, we studied the effects of nonlethal predation risk throughout the embryonic development of newly spawned eggs carried by female shrimp on the timing of egg hatching, hatchling morphology, larval development and juvenile morphology. We also determined maternal body mass at the end of the embryonic period. Exposure to predation risk cues during embryonic development led to larger larvae which also had longer rostra but reached the juvenile stage sooner, at a smaller size and with shorter rostra. There was no difference in hatching timing, but changes in larval morphology and developmental timing showed that the embryos had perceived waterborne substances indicative of predation risk. In addition to carryover effects on larval and juvenile stages, predation threat provoked a decrease of body mass in mothers exposed to predator cues while brooding. Our results suggest that risk-exposed embryos were able to recognize the same infochemicals as their mothers, manifesting a response in the free-living larval stage. Thus, future studies assessing anti-predator phenotypes should include embryonic development, which seems to determine the morphology and developmental time of subsequent life-history stages according to perceived environmental conditions.     

温度对桃蛀螟生长发育和繁殖的影响

为了明确温度对桃蛀螟Conogethes punctiferalis (Guenée)生长发育和繁殖的影响, 本实验在恒温条件（15, 19, 23, 27和31℃共5个温度梯度）下, 以板栗为寄主食料, 研究了温度对桃蛀螟实验种群生长发育和繁殖的影响。结果表明： 温度对桃蛀螟各虫态的发育历期、 存活率、 蛹重以及种群繁殖力有显著影响。在15~27℃范围内, 各虫态的发育历期均随温度的升高而缩短, 发育速率与温度呈显著正相关。但是, 当温度上升至31℃时, 幼虫生长发育受到抑制, 其发育历期比27℃时延长了1.11 d, 而卵期、 蛹期和产卵前期仍符合随温度升高趋于缩短的趋势。此外, 15℃下桃蛀螟5龄幼虫发育停滞, 表明老熟幼虫的发育起点温度高于其他低龄幼虫。桃蛀螟世代存活率随环境温度变化的大小顺序为23℃>27℃>19℃>31℃, 其中, 23~27℃的存活率较高, 为54.44%~63.56%, 31℃时为4.30%, 说明温度过高或过低均不利于其生长发育。成虫产卵量在23℃时最高, 单雌平均产卵量达55.00粒, 其次为19℃和27℃, 单雌平均产卵量分别为43.30和39.70粒; 31℃下产卵量最少, 仅为20.90粒。由直接最优法计算得到桃蛀螟卵期、 幼虫期、 蛹期、 产卵前期及全世代的发育起点温度分别为10.37, 10.06, 14.27, 7.47和11.85℃, 有效积温依次为70.84, 287.71, 118.42, 58.33和509.06日度。研究结果为桃蛀螟发生期的预测预报提供了基础参考数据, 对指导生产实践有实际的应用意义。     

Effects of embryo energy,egg size,and larval food supply on the development of asteroid echinoderms

Organisms have limited resources available to invest in reproduction, causing a trade‐off between the number and size of offspring. One consequence of this trade‐off is the evolution of disparate egg sizes and, by extension, developmental modes. In particular, echinoid echinoderms (sea urchins and sand dollars) have been widely used to experimentally manipulate how changes in egg size affect development. Here, we test the generality of the echinoid results by (a) using laser ablations of blastomeres to experimentally reduce embryo energy in the asteroid echinoderms (sea stars), Pisaster ochraceus and Asterias forbesi and (b) comparing naturally produced, variably sized eggs (1.7‐fold volume difference between large and small eggs) in A. forbesi. In P. ochraceus and A. forbesi, there were no significant differences between juveniles from both experimentally reduced embryos and naturally produced eggs of variable size. However, in both embryo reduction and egg size variation experiments, simultaneous reductions in larval food had a significant and large effect on larval and juvenile development. These results indicate that (a) food levels are more important than embryo energy or egg size in determining larval and juvenile quality in sea stars and (b) the relative importance of embryo energy or egg size to fundamental life history parameters (time to and size at metamorphosis) does not appear to be consistent within echinoderms.     

Egg size and the evolution of phenotypic plasticity in larvae of the echinoid genus Strongylocentrotus

Planktotrophic larvae grow by utilizing energy obtained from food gathered in the plankton. Morphological plasticity of feeding structures has been demonstrated in multiple phyla, in which food-limited larvae increase feeding structure size to increase feeding rates. However, before larvae can feed exogenously they depend largely on material contained within the egg to build larval structures and to fuel larval metabolism. Thus, the capacity for plasticity of feeding structures early in development may depend on egg size. Using the congeneric sea urchins Strongylocentrotus franciscanus and S. purpuratus, which differ in egg volume by 5-fold, I tested whether the degree of expression of feeding structure (larval arm length) plasticity is correlated with differences in the size of the egg. I experimentally manipulated egg size of S. franciscanus (the larger-egged species) by separating blastomeres at the 2-cell stage to produce half-sized larvae. I reared half-size and normal-size larvae under high and low food treatments for 20 days. I measured arm and body lengths at multiple ages during development and calculated the degree of plasticity expressed by larvae from all treatments. Control and unmanipulated S. franciscanus larvae (from ∼ 1.0 nl eggs) had significantly longer arms relative to body size and a significantly greater degree of plasticity than half-sized S. franciscanus larvae (from < 0.18 nl eggs), which in turn expressed a significantly greater degree of plasticity than S. purpuratus larvae (from ∼ 0.3 nl eggs). These results indicate that egg size affects larval arm length plasticity in the genus Strongylocentrotus; larger eggs produce more-plastic larvae both in an experimental and a comparative context. However, changes in egg size alone are not sufficient to account for evolved differences in the pattern of plasticity expressed by each species over time and may not be sufficient for the evolutionary transition from feeding to non-feeding.     

Fecundity, lifespan and egg mass in butterflies: effects of male-derived nutrients and female size

1. Effects of larval reserves and nutrients received as adults on fecundity and lifespan in female Danaus plexippus (the Monarch Butterfly) were measured to determine the relative importance of different sources of nutrients for reproduction and somatic maintenance.
2. Egg-laying lifespan was correlated with female size but not with the amount of male-derived nutrients or adult food concentration.
3. Lifetime fecundity was higher when females received a large first spermatophore, but was not affected by female size when lifespan was controlled or by adult food concentration.
4. At the end of their lives, females contained unlaid eggs and retained, on average, 88% of their initial mass. This proportion was unchanged in two years, although mean egg-laying lifespan varied from 22·5 to 28·7 days.
5. Egg mass decreased over the female lifespan, and was correlated with female size.
6. These results suggest that larval reserves are more important for somatic maintenance than adult income, but that the protein-rich nutrients received from males contribute to egg production. This supports theoretical predictions and empirical studies of other Lepidoptera showing that larval reserves are less likely to affect fecundity when the adult income can contribute substantially to egg production.