Fecundity and juvenile survival of shape Bembidion lampros and Tachyporus hypnorum

Fecundity and development from first instar larvae to adult beetles were studied for Bembidion lampros Herbst (Coleoptera; Carabidae) and Tachyporus hypnorum F. (Coleoptera; Staphylinidae). Both species reproduce in arable fields, where they are known to contribute to the natural control of cereal aphids. They are univoltine and have similar life cycles and development times. T. hypnorum females laid approximately 3 times more eggs than B. lampros females. Relative lifetime fecundity of B. lampros was very low with an average of 10 eggs per female. Based on the time where half of the populations had dispersed from the overwintering sites into an arable field B. lampros started egg-lay 100°D (°C>9) and T. hypnorum 200°D (°C>3) after dispersal. Mortality in the juvenile stages was found to be an important factor in the population dynamics of both B. lampros and T. hypnorum. The survival from first instar larvae to adults was on average 34% for B. lampros independent of soil type, 21% for T. hypnorum developed in sandy soil and 49% when developed in clayey soil under semi-field conditions. Enlargement of B. lampros and T. hypnorum populations to increase the natural control of aphids during their establishment in cereal fields may be possible if the conditions for juvenile development are improved.     

Adult polyphagous coleopterans overwintering in cereal boundaries: winter mortality and susceptibility to the entomopathogenic fungus Beauveria bassiana

Autumn-collected Bembidion lampros and Agonum dorsale were kept outdoors under semi field conditions to determine winter mortality. On three occasions (autumn, mid-winter and late winter) sub-samples of the population were incubated in the laboratory at room temperature and mortality was recorded. Generally the mortality was low in autumn and mid-winter, not exceeding 5%. A more pronounced post-winter mortality of up to 30% was observed at the end of hibernation. Only a negligible number were infected by the entomopathogenic fungi Beauveria bassiana and Paecilomyces farinosus. Infection experiments with B. bassiana isolates from Sitona lineatus, Tachyporus hypnorum and three species of ground beetles showed a similarly low susceptibility of B. lampros and A. dorsale to B. bassiana and, although Tachyporus spp. showed a distinct mycophagy and a significantly higher mortality, this could not be related to mycosis.     

Factors affecting cold hardiness in the small striped flea beetle, Phyllotreta undulata

The striped flea beetle, Phyllotreta undulata Kutschera (Coleoptera: Chrysomelidae), is a pest of cruciferous crops. It overwinters as an adult. During winter in northern European countries, such as Estonia, it is subject to sometimes severe temperatures that may fluctuate daily, over the season, and between seasons. The objective of this study was to investigate factors that affect its cold hardiness. In a series of five experiments, the effects of food plant, starvation, and acclimatization on the beetles’ ability to supercool and survive exposure to sub‐zero temperatures was investigated. The supercooling points (SCP) of overwintered beetles field‐collected from white mustard and Indian mustard differed from those caught from white cabbage and oilseed rape, but these differences disappeared after a 4‐day period of starvation at room temperature, indicating that gut content probably influences the potential to supercool. The duration and temperature of acclimation affected SCP in overwintered beetles. The decrease in SCP was more rapid at 22 °C than at 0 °C, probably because of faster dehydration and gut evacuation at the higher temperature. Acclimation at 0 °C for a week increased the ability of overwintered beetles to survive sub‐zero temperatures, lowering both SCP and lower lethal temperature (LLT₅₀). Some pre‐freeze mortality occurred; SCP and LLT₅₀ were correlated but the latter was a constant 3 °C higher than the former. The SCP of field‐collected pre‐winter beetles decreased gradually during the autumn. It also decreased when field‐collected pre‐winter beetles were acclimated at 0 °C in the laboratory, attaining its lowest level after 18 days. Phyllotreta undulata is well‐adapted to unstable and sometimes severe winter conditions; its high potential to supercool enhances its cold hardiness and ability to survive short periods at sub‐zero temperatures although it cannot survive freezing of its body fluids.     

Relative Importance of Sex,Pre-Starvation Body Mass and Structural Body Size in the Determination of Exceptional Starvation Resistance of Anchomenus dorsalis (Coleoptera: Carabidae)

In nature, almost all animals have to cope with periods of food shortage during their lifetimes. Starvation risks are especially high for carnivorous predatory species, which often experience long intervals between stochastic prey capturing events. A laboratory experiment using the common predatory carabid beetle Anchomenus dorsalis revealed an exceptional level of starvation resistance in this species: males survived up to 137 days and females up to 218 days without food at 20°C. Individual starvation resistance was strongly positively affected by pre-starvation body mass but only slightly by beetle structural body size per se. Females outperformed males even when the effect of gender was corrected for the effects of structural body size and pre-starvation body mass. The better performance of females compared to males and of beetles with higher relative pre-starvation body mass could be linked to higher fat content and lean dry mass before starvation, followed by a greater decrease in both during starvation. There was also a difference between the sexes in the extent of body mass changes both during ad libitum feeding and following starvation; the body masses of females fluctuated more compared to males. This study stresses the need to distinguish between body mass and structural body size when investigating the ecological and evolutionary consequences of body size. Investigation of the net effects of body size and sex is necessary to disentangle the causes of differences in individual performances in studies of species with significant sexual size dimorphism.     

Life cycle and food availability indices in Notiophilus biguttatus (Coleoptera, Carabidae)

Abstract.

• 1 Food demands of the predatory carabid Notiophilus biguttatus F. and their fulfilment were studied in the laboratory and field.
• 2 In the laboratory, larval consumption, growth, adult body size and egg production were established for different regimes of temperature and food, the springtail Orchesella cincta.
• 3 Temperature strongly influenced feeding rate of larvae and adults and consequently growth and oviposition rates. Accordingly, growth rate and ovi-position rate increased with prey supply.
• 4 Prey supply also had an effect on fat content, but the number of ripe eggs in the ovaries was related neither to temperature nor to prey supply.
• 5 Adult body size was affected by temperature during the larval period but more so by food supply.
• 6 Dissection of field fresh females showed them to bear eggs for the whole year, except in late winter/early spring and in July.
• 7 Fat content was low in spring and, from July on, high in summer and autumn. Survivorship during starvation differed widely between samples and seemed to be related to reproductive status rather than to fat content.
• 8 Samples of beetles and springtails from eleven pine plantations revealed for the beetles significant differences in fat content and body size, the latter ranging between the maximum and minimum value obtained in the laboratory.
• 9 Conclusions about food limitation based on body size and fat content were not corroborated by a relationship of these indices with springtail density.

     

The effects of habitat,density, gender and duration on overwintering success in Bembidion lampros (Coleoptera: Carabidae)

In temperate climates, winter mortality is a key factor influencing insect survival. In Bembidion lampros (Coleoptera: Carabidae), an abundant polyphagous predator in arable farmland, we investigated how habitat, population density, gender and duration of overwintering affect the winter mortality and body condition of survivors. In a field experiment, we introduced beetles at two population densities into isolators placed either in the interior of the field or in the grassy boundary. Half of the isolators were collected in mid‐March, and the remaining half were collected in mid‐April. Across all treatments, 44–92% of the beetles survived until spring. Survival was significantly higher in the field interior than in the boundary. The longevity of individuals starved after overwintering was higher in females than in males and was positively related to the length of time spent at the overwintering site. Population density was positively related to percentage survival but did not affect body condition. Our results suggest that biotic factors such as population density and predation, though little studied, may have a similar significance as abiotic factors. Even ubiquitous carabid species inhabiting agroecosystems have specific requirements for overwintering. Understanding these requirements is useful for developing techniques to support their overwintering success.     

Strategic diel regulation of body mass in European robins

Stochastic dynamic programming (SDP) is a computational technique that has been used to model daily routines of foraging in small birds. A diurnal bird must build up its fat reserves towards dusk in order to avoid starvation during the night, when it cannot feed. However, as well as the benefits of avoiding starvation, storing fat imposes costs such as an increased predation risk and higher flight and metabolic costs. There is therefore an optimal level of fat reserves for a bird to reach at dusk in order to survive overnight without being left with excessive fat reserves at dawn. I tested a prediction common to all SDP models of daily foraging routines, that a bird will attempt to reach this level at dusk, regardless of its fat reserves the previous dawn. I provided supplementary food to manipulate the fat reserves at dawn of free-living European robins, Erithacus rubecula. Diurnal changes in body mass (a reliable estimate of fat reserves) were then monitored remotely. Robins provided with an ad libitum food supply reached almost exactly the same body mass at dusk, regardless of their body mass at dawn, supporting the prediction that birds attempt to reach a target level of reserves at dusk. Copyright 2000 The Association for the Study of Animal Behaviour.     

Effect of sex and season on the production and deposition of lipid and glycid reserves in the intermittently starving golden hamster.

In golden hamster adapted to intermittent starvation (with access to food for 3 days a week only), the glycogen and lipid content of the liver, total body fat and RQ values measured in vivo were investigated. These parameters were studied in dependence on the duration of the adaptation period (6 weeks versus 20 weeks), season of the year (winter versus summer) and sex. The liver glycogen content in intermittently starved males and females increases after 6 weeks of adaptation during winter. In summer an increase was found after long-term adaptation, but only in males. Male hamsters also exhibited a higher ability to accumulate liver lipids during both seasons. In spite of their lower weight intermittently starving males have a higher percentage of body fat in comparison with females, a stimulating effect being observed in winter. Increased lipogenesis in golden hamsters adapted to intermittent starvation may be concluded from the increased RQ values when compared with relative data gained in controls fed daily ad libitum. Significant differences between RQ measurements according to season and sex were not found.     

Survival of parent and brood adult bark beetles, Ips typographus, in relation to size, lipid content and re-emergence or emergence day

ABSTRACT. This study investigated a possible trade-off between bark beetle reproductive effort and future survival. Parent adult Ips typographus (L.) (Coleoptera: Scolytidae) were collected when they re-emerged from a laboratory culture after completing their first brood and held at constant temperatures of 4 or 25^oC. As a comparison, emerging brood adults were collected and held at 25^oC. The longevity of the beetles was related to when they re-emerged or emerged (measured in days since parent introduction) and to their size (pronotal width), fresh weight and lipid content at collection, by multiple regression analysis. The expression (fresh weight x pronotal width ^-2.6), used as an estimate of lipid content of the living beetles, was significantly correlated (r=0.67, P<0.001) with the actual (extracted) lipid content. At 25^oC, fat content was the variable most strongly correlated with survival time in all beetle groups except parent females. In both parent and brood females, re-emergence or emergence day, respectively, contributed significantly to the explanation of survival time, whereas pronotal width and fresh weight never contributed significantly to the regression equation. At 4^oC, fat content was not estimated but, re-emergence day was negatively correlated with survival time. In conclusion, beetles with high fat content and re-emerging or emerging early have longer expected survival than beetles leaving the log later or containing less fat. This means that females laying a large first brood might suffer a somewhat higher mortality than females laying a smaller brood.     

Effects of aestivation and starvation on the neutral lipid and phospholipid content of Biomphalaria glabrata infected with Schistosoma mansoni

The effects of aestivation or starvation on the neutral lipid and phospholipid content of Biomphalaria glabrata patently infected with Schistosoma mansoni were determined by high-performance thin-layer chromatography-densitometry. Infected-aestivated snails were maintained in a moist chamber at 24 +/- 1 C and a relative humidity of 98 +/- 1%. Infected-starved snails were maintained in artificial spring water (ASW) at 23 +/- 1 C without exogenous food. Infected snails (the controls) were maintained in ASW at 23 +/- 1 C and fed lettuce ad libitum. The 3 groups were maintained in the laboratory for 7 days, and then the lipids from the digestive gland-gonad complex (DGG) were extracted and analyzed by class. Infected-aestivated snails exhibited greater mortality rate and weight loss after 7 days than did the infected-starved snails. The steryl ester concentration in the infected-starved snails was significantly increased (P = 0.010) compared with the controls but not compared with infected-aestivated snails; the concentration of phosphatidylcholine in infected-aestivated snails was significantly decreased (P = 0.007) compared with the controls but not when compared with the infected-starved snails. Aestivation or starvation had a significant effect on the concentration of certain lipid classes in the DGG of B. glabrata infected with S. mansoni.     

Changes in metabolite concentration in the plasma, liver and muscle of feed restricted Japanese quail exposed to cold.

Quail fed ad libitum and 50% ad libitum were cold exposed for several weeks, during time control quail remained at 21 degrees C. The concentration of plasma glucose, FFA, and uric acid, tissue glycogen and carcass fat content was measured at the end of the cold exposure period. Quail fed ad libitum showed no significant change in the levels of plasma and tissue metabolites, or the carcass fat content, following cold exposure. The feed consumption by the cold exposed quail increased, and the mean body weight showed little variation from that of the controls. Feed restricted quail which were cold exposed lost significantly more weight, and had a lower ranked fat content than their controls. Whereas feed restriction caused a lowering of the liver glycogen concentration in both treatment groups, muscle glycogen levels were higher than in quail fed ad libitum. However, cold exposure was not accompanied by a change in muscle and liver glycogen levels in feed restricted quail. Feed restricted quail at 21 degrees C were hypoglycaemic and hyperlipaemic compared to quail fed ad libitum, but cold exposed feed restricted quail had a much higher plasma glucose concentration than the controls. The ranked carcass fat content was inversely related to plasma FFA level in both control and cold exposed feed restricted quail. It is suggested that both a glycolytic and lipid mobilizing response to cold is obtained in quail whose body reserves are not spared from catabolism by adequate dietary nutrient absorption, and the possibility of gluconeogenesis from precursors produced by proteolysis is indicated.     

Effects of three simultaneous demands on glucose transport, resting metabolism and morphology of laboratory mice

In nature, animals must successfully respond to many simultaneous demands from their environment in order to survive and reproduce. We examined physiological and morphological responses of mice given three demands: intestinal parasite infection with Heligmosomoides polygyrus followed by caloric restriction (70% of ad libitum food intake versus ad libitum for 10 days) and/or cold exposure (5°C vs. 23°C for 10 days). We found significant interactions between these demands as well as independent effects. Small intestine structure and function changed with demands in both independent and interactive ways. Body mass decreased during caloric restriction and this decrease was greater for cold-exposed than warm-exposed mice. In ad libitum fed mice, body mass did not change with either cold exposure or parasite infection but body composition (fat versus lean mass of whole body or organs) changed with both demands. Generally, organ masses decreased with caloric restriction (even after accounting for body mass effects) and increased with cold exposure and parasite infection whereas fat mass decreased with both caloric restriction and parasite infection. Mass adjusted resting metabolic rate (RMR) increased with cold exposure, decreased with caloric restriction but, unlike previous studies with laboratory mice, did not change with parasite infection. Our results demonstrate that the ability of mice to respond to a demand is influenced by other concurrent demands and that mice show phenotypic plasticity of morphological and physiological features ranging from the tissue level to the level of the whole organism when given three simultaneous demands.     

Body mass and behavior in Swiss mice subjected to continuous or discontinuous food restriction and refeeding

Food restriction (FR) is hypothesized to decrease body fat content of an animal and thus prevent obesity. However, the response of energy budget to a continuous (CFR) or discontinuous FR (DFR) remains inconsistent. In the present study, effects of CFR or DFR and refeeding on energy budget and behavior were examined in male Swiss mice. CFR significantly decreased the energy expenditure associated with basal metabolic rate (BMR) and activity behavior, but not sufficiently to compensate for energy deficit and thus resulted in lower body mass and fat content. DFR mice had a significantly higher food intake on ad libitum days and showed increases in BMR and activity after 4 weeks’ DFR, which might resulted in lower body mass and less body fat than controls. After being refed ad libitum, both CFR and DFR mice had similar body mass, BMR, and behavioral patterns to controls but had 95% and 75% higher fat content. This suggested that not only CFR but also DFR would be a significant factor in the process of obesity for animals that were refed ad libitum. It also indicated that food restriction interrupted many times by periods of ad libitum feeding had the same long-term effects like continuous underfeeding.     

Intracellular freezing, viability, and composition of fat body cells from freeze-intolerant larvae of Sarcophaga crassipalpis.

Although it is often assumed that survival of freezing requires that ice formation must be restricted to extracellular compartments, fat body cells from freeze-tolerant larvae of the gall fly, Eurosta solidaginis (Diptera, Tephritidae) survive intracellular freezing. Furthermore, these cells are highly susceptible to inoculative freezing by external ice, undergo extensive lipid coalescence upon thawing, and survive freezing better when glycerol is added to the suspension medium. To determine whether these traits are required for intracellular freeze tolerance or whether they are incidental and possessed by fat body cells in general, we investigated the capacity of fat body cells from nondiapause-destined and diapause-destined (i.e., cold-hardy) larvae of the freeze-intolerant flesh fly Sarcophaga crassipalpis (Diptera, Sarcophagidae) to survive intracellular freezing. Fat body cells from both types of larvae were highly susceptible to inoculative freezing; all cells froze between -3.7 to -6.2 degrees C. The highest rates for survival of intracellular freezing occurred at -5 degrees C. The addition of glycerol to the media markedly increased survival rates. Upon thawing, the fat body cells showed little or no lipid coalescence. Fat body cells from E. solidaginis had a water content of only 35% compared to cells from S. crassipalpis larvae that had 52-55%; cells with less water may be less likely to be damaged by mechanical forces during intracellular freezing.     

Quantifying food limitation of arthropod predators in the field

A method for quantifying food limitation of arthropod predators in the field is presented and applied to species of ground beetles (Carabidae) and sheet-web spiders (Linyphiidae) from a cereal field. Food limitation is expressed quantitatively as accumulated hunger (=starvation) by transforming 24-h food consumption at 20°C of animals newly collected in the field into days of starvation at 20°C. This is done by means of a reference curve relating 24-h food intake at 20°C to starvation periods (days) at 20°C. Such a reference curve was obtained for the carabid beetle Agonum dorsale in the laboratory. For other species the reference curve was modified with species-specific data. The procedure makes it possible to compare the feeding conditions of different species populations that are part of the same community. Hunger levels in the field for females of A.␣dorsale were equivalent to c. 15 days of starvation in early spring, c. 5 days in June, increasing to c. 10 days in late summer. Two ground beetles occurring during summer also showed increasing hunger levels from June to July, probably the result of a dry summer. Two spider species experienced a hunger level in the range of 4–8 days of starvation. Received: 15 August 1997 / Accepted: 22 January 1998     

Studies on lipogenesis in vivo. Lipogenesis during extended periods of re-feeding after starvation

1. Lipogenesis was studied in mice re-fed for up to 21 days after starvation. At appropriate times [U-(14)]glucose was given by stomach tube and incorporation of (14)C into various lipid fractions measured. 2. In mice starved for 48hr. and then re-fed for 4 days with a diet containing 1% of corn oil, incorporation of (14)C from [U-(14)C]glucose into liver fatty acids and cholesterol was respectively threefold and eightfold higher than in controls fed ad libitum. The percentages by weight of fatty acids and cholesterol in the liver also increased and reached peaks after 7 days. Both the radioactivity and weights of the fractions returned to control values after 10-14 days' re-feeding. These changes could be diminished by re-feeding the mice with a diet containing 20% of corn oil. Incorporation of (14)C from [U-(14)C]glucose into extrahepatic fatty acids (excluding those of the epididymal fat pads) was not elevated during re-feeding with a diet containing either 1% or 20% of corn oil. However, incorporation of (14)C from [U-(14)C]glucose into the fatty acids of the epididymal fat pads was increased in mice re-fed with either diet, as compared with non-starved controls. 3. Lipogenesis was also studied in mice alternately fed and starved. Mice given a diet containing 1% of corn oil for 6hr./day for 4 weeks lost weight initially and never attained the weight or carcass fat content of controls fed ad libitum. Incorporation of (14)C from dietary [U-(14)C]-glucose into the fatty acids of the epididymal fat pads was elevated threefold in the mice allowed limited access to food, although the incorporation into the remainder of the extrahepatic fatty acids was not different from that found for controls. Mice given a diet containing 20% of corn oil for 6hr./day adapted to the limited feeding regimen quicker and in 4 weeks did attain the weight and carcass fat content of controls. Incorporation of (14)C from [U-(14)C]glucose into the fatty acids of the epididymal fat pads and the remainder of the extrahepatic fatty acids was respectively fivefold and threefold higher than in controls fed ad libitum. 4. The elevation in liver lipogenesis during re-feeding was greatest on a diet containing 1% of corn oil, whereas in extrahepatic tissues the increase in lipogenesis was greater when the mice were re-fed or were allowed limited access to a diet containing 20% of corn oil. These results suggest that the causes of the increased rate of incorporation of (14)C from [U-(14)C]glucose into fatty acids during re-feeding may be different in liver from that in extrahepatic tissues.     

On the importance of fat reserves for the little auk (Alle alle) chicks

Summary The pattern of fat deposition and inter-year variation in the amount of deposited fat, lean dry mass (LDM) and water were studied in the chicks of little auk (Alle alle), an arctic alcid, at Spitsbergen in the 1984, 1986 and 1987 breeding seasons. The lipid index (lipid mass/LDM) rose from 0.29 at hatching to about 0.70 at the age of maximum body mass attained in the nest, the highest yet recorded for seabirds except procellariiforms. Just before fledging the index dropped to 0.38. Fat mass in 1984 chicks and also fresh body mass of older 1984 chicks was significantly lower than in the other two seasons, but there were no statistical year-to-year differences in LDM's of chicks. The amount of fat in chicks was significantly correlated with certain weather parameters. Fasting capability (FC) of the chicks (the time that chicks could survive when using only their lipid stores) was calculated from fat mass and previous data on metabolic rates of chicks. The FC's of all 108 chicks collected in three seasons were greater than maximum interval between two consecutive feeds to chicks reported in the study colony. Also the estimated fat reserves of 99.7% of chicks weighed in 1984 were sufficient to support them for longer than the maximum recorded intervals between feeds. In relation to death by starvation, little auk chicks, at least up to the age of maximum body mass, have a substantial surplus of fat. This is contrary to the hypothesis that fat depots in seabird chicks assist survival during the periodic fasts resulting from unpredictable feeding conditions.     

Small-scale spatiotemporal variability in body size of two common carabid beetles

Adult body size is one of the most ecologically relevant quantitative traits that underlies many other life-history traits of particular organism. In insects, there is positive intraspecific relationship between body size and female fecundity. In this study small scale temporal and spatial and space variability in structural body size of Poecilus cupreus and Anchomenus dorsalis was investigated. The beetles were collected in four fields near Prague-Suchdol in autumn 2009 and 2010, and in spring 2010, 2011 and 2012. In both species structural body size was significantly affected by sex (females were the larger sex). In A. dorsalis structural body size was also significantly affected by arable field identity, overwintering (post-overwintering individuals collected in spring were larger in comparison to pre-overwintering individuals collected in autumn), sampling year, overwintering by year and arable field by year interactions. Our results suggest that spatiotemporal variation in environmental conditions experienced by A. dorsalis during larval growth resulted in differences in adult structural body size among particular fields and particular sampling years. In addition, mean structural body size in A. dorsalis was affected by overwintering, which was probably caused by size-specific winter mortality. Moreover, effect of overwintering varied among years, probably according to the specific weather conditions during a particular winter.     

The abundance and reproductive activity of common Carabidae in a winter wheat crop

Abstract. 1. The number of common carabid beetles trapped-irr a wheat field on a clay with flint soil from May to October in.1971–77 differed greatly: Harpalus rufipes and Pterostichus melanarius were numerous every year; but the appearance of H.aeneus, P.madidus, Agonum dorsale, Nebria brevicollis, Notiophilus biguttatus, Bembidion lampros and Trechus quadristriatus was much more variable.
2. The numbers caught were not correlated with rainfall. Catches of the large species were positively correlated with accumulated temperature above an assumed activity threshold of 5°C, whereas the smaller beetles were negatively correlated with accumulated temperature, suggesting that the danger of desiccation at high temperatures limits their activity.
3. The egg-laying periods of the commonest species were: B.lampros and A.dorsale from late April to June; overwintered P.melanarius, H.rufipes and H.aeneus in May and June, with the summer generation of these species and of P.madidus from July to September; T.quadristriatus during August and September; N.brevicollis from September to November; N.biguttatus and C.fossor laid in the early summer and again in the autumn.
4. A few male and female H.rufipes and H.aeneus , and one female P.melanarius and N.brevicollis were each parasitized by a single tachinid larva; one P.melanarius was infested with a mermithid parasite.     

Metabolic changes in the African fruit beetle,Pachnoda sinuata,during starvation

Specimens of the fruit beetle Pachnoda sinuata were starved for up to 30 days. The weight of the beetles declined consistently throughout the starvation period. Concentrations of carbohydrates and alanine in flight muscles, fat body and haemolymph decreased rapidly after onset of starvation, while the concentration of proline remained high. Whereas the lipid concentrations in the haemolymph did not change significantly upon starvation, the lipid content in flight muscles and fat body decreased significantly.Beetles that had been starved for 14 days responded to injection of Mem-CC, the endogenous neuropeptide from its corpora cardiaca, with hyperprolinaemia and a decrease in the alanine level, but no such effect was monitored after prolonged starvation of 28 days. Regardless of the period of starvation, Mem-CC injection could not cause hypertrehalosaemia or hyperlipaemia, although carbohydrates were increased in fed beetles after injection.Flight ability of beetles that had been starved for 15 or 30 days was apparently not impaired. During such periods, beetles used proline exclusively as fuel for flight as evidenced by the increase in the level of alanine in the haemolymph and decrease of the level of proline; the concentrations of carbohydrates and lipids remained unchanged.Activities of malic enzyme and alanine aminotransferase (enzymes involved in transamination in proline metabolism), glyceraldehyde-3-phosphate dehydrogenase (enzyme of glycolysis), 3-hydroxyacyl-CoA dehydrogenase (enzyme of beta-oxidation of fatty acids) and of malate dehydrogenase (enzyme of Krebs cycle) were measured in fat body and flight muscles. In flight muscle tissue the maximum activity of NAD(+)-dependent malic enzyme increased, while that of glyceraldehyde-3-phosphate dehydrogenase decreased during starvation, and malate dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase and alanine aminotransferase were unchanged. In fat body tissue, activities of NADP(+)-dependent malic enzyme and 3-hydroxyacyl-CoA dehydrogenase increased during food deprivation and activities of glyceraldehyde-3-phosphate dehydrogenase, malate dehydrogenase and alanine aminotransferase remained unchanged.