Lower Fat Reserves Research Articles

Thinner bats to face hibernation as response to climate warming

One of the principal consequences of climate warming on hibernating mammals could be the loss of optimal conditions for hibernation. Although hibernating mammals, like bats, may be particularly vulnerable to climate warming due to a potential reduction of energy saving during the hibernation, there is a lack of knowledge regarding how they will be affected and how they will respond to this impact. Here, we examine the variation in the body condition of Schreiber’s bent-winged bat (Miniopterus schreibersii) to investigate changes in the optimization energy demand. Using a 20-year dataset (1998–2017), we analyse the temporal trends of body condition in three key stages of the hibernation period: onset and end of hibernation and early activity. Our results indicate that body condition at the onset and end of hibernation have decreased significantly over these 20 years. However, despite this lower body condition, the decrease of mass loss rate in the last decade (although not significant) indicate a greater saving of fat reserves. The significant increase in winter temperatures did not affect body condition or reserve depletion, instead, lower body condition was observed with a higher number of days below 0 °C. Unlike other hibernating bat species, the females had lower fat reserves than males in all three periods considered. This study indicates that hibernation energy requirements could be changing as an adaptation to a warmer climate and that hibernating bats can survive the winter by optimizing their lower accumulation of reserves.

Experimental warming reduces body mass but not reproductive investment.

Climate change has already had wide-ranging effects on populations, including shifts in species' ranges, phenology, and body size. Whereas some common patterns have emerged, the direction and magnitude of responses vary extensively among populations as well as across life stages within populations. Understanding the consequences of climate change and predicting future responses at the population level require experimental tests of how warmer temperatures affect life history traits, including growth rate, development time, and reproductive output. Here, we tested how experimental warming affected life history from larval development and survival to adult reproductive maturity and investment in mole salamanders, Ambystoma talpoideum. We found that a small temperature increase (~1°C) experienced during larval development had complex consequences: density-dependent effects on growth and body mass, density-independent effects on fat storage, and no effects on survival and reproductive investment. Although warming reduced growth rates, size at maturity, and fat storage, salamanders in both warmed and control conditions had similar survival and reproductive investment in their first year. However, costs of smaller body size and lower fat reserves may limit overwintering survival and/or future reproduction. Our study highlights the differential effects of warming across life history traits and multifaceted population responses to climate change. This work motivates future studies to examine variation in response to climate change across life stages and life history traits.

Nephridiophagids (Chytridiomycota) reduce the fitness of their host insects

Nephridiophagids are unicellular fungi (Chytridiomycota), which infect the Malpighian tubules of insects. While most life cycle features are known, the effects of these endobionts on their hosts remain poorly understood. Here, we present results on the influence of an infection of the cockroach Blattella germanica with Nephridiophaga blattellae (Ni = Nephridiophaga-infected) on physical, physiological, and reproductive fitness parameters. Since the gut nematode Blatticola blattae is a further common parasite of B. germanica, we included double infected cockroaches (N + Ni = nematode plus Ni) in selected experiments. Ni individuals had lower fat reserves and showed reduced mobility. The lifespan of adult hosts was only slightly affected in these individuals but significantly shortened when both Nephridiophaga and nematodes were present. Ni as well as N + Ni females produced considerably less offspring than parasite-free (P-free) females. Immune parameters such as the number of hemocytes and phenoloxidase activity were barely changed by Nephridiophaga and/or nematode infections, while the ability to detoxify pesticides decreased. Quantitative proteomics from hemolymph of P-free, Ni, and N + Ni populations revealed clear differences in the expression profiles. For Ni animals, for example, the down-regulation of fatty acid synthases corroborates our finding of reduced fat reserves. Our study clearly shows that an infection with Nephridiophaga (and nematodes) leads to an overall reduced host fitness.

Association of weather variables with the migration phenology and body conditions of Siberian warblers

Different elements of weather, such as wind speed, wind direction, precipitation and temperature are very important regulators of bird migration. Weather conditions also play role on the body condition such as body mass and the deposited fat. In this study we selected four warbler species to examine the impact of different weather variables on their spring and autumn migration timing and their body condition in one of the most extreme weather areas of the Earth, at Lake Baikal in Siberia. We also studied the changes in body mass and fat reserves during the spring and autumn migration periods of these species. For the analyses, we used ringing data of 2471 birds from five spring and five autumn seasons during 2015–2019. According to our results, it can be stated that the weather did not have a significant association with the migration timing of the studied warblers, perhaps due to the geographical location of the study site. However, the body mass and the fat reserves of the birds increased during unsuitable weather conditions because of the increased energy requirements. Birds generally migrate with low fat reserves, which is due to the fact that this area is not an important stopover site for these species.

Message of the WHO Representative to the Philippines

Globally, an estimated 2.4 million children died in their first month of life in 2019. This translated to 6,700 newborn deaths every day, and accounted for 47% of all child deaths under the age of 5 years.
 The world has made substantial progress in child and newborn survival since 1990. However, 75% of newborn deaths continue to occur in the first week of life and about 1 million newborns die within their first 24 hours of life. In the Philippines, an estimated 63,000 of 1.7 million children born in 2019 died before their fifth birthday, with half occurring among newborns.
 Preterm birth, intrapartum-related complications such as birth asphyxia, infections and birth defects, caused most neonatal deaths in 2019.
 While child deaths decreased by one-half between 1990 and 2018, newborn mortality declined at half that rate. Along with asphyxia and sepsis, complications of prematurity are the main causes of newborn deaths. Preterm (< 37 weeks gestation) and low birth weight (LBW) (<2500 g) babies have immature immune and organ systems, low fat reserves and reduced muscle mass, placing them at a much higher risk for hypothermia, infection, and death, compared to babies born with normal weight.
 Kangaroo mother care (KMC) is a technique of caring for preterm and LBW babies which consists of keeping them in skin-to-skin contact (SSC) on the chest of the mother (or other family members), as early and as long as possible, exclusive breastfeeding, and early discharge from the hospital with close monitoring on an outpatient basis.
 KMC has been demonstrated to reduce mortality in small babies by almost half compared to conventional incubator-based neonatal intensive care. Other benefits include prolonged duration of exclusive breastfeeding and better growth rates. Thus, the World Health Organization (WHO) recommends KMC for babies less than or equal to 2,000 grams. We also support widespread calls to introduce, accelerate, and sustain quality KMC implementation.
 It is with this note that I congratulate the Kangaroo Mother Care Foundation Philippines, and the research authors for all their original scientific papers on KMC. The publication of these studies, present added evidence that KMC is a cost-efficient, readily available, effective strategy for saving the lives of babies born either prematurely, or with low birth weight for age.
 
 
 Rabindra Abeyasinghe, MD, MSc, DTM&H (Public Health) WHO Representative to the Philippines

Physiological costs and age constraints of a sexual ornament: an experimental study in a wild bird

Abstract Sexual ornaments are often considered honest signals of quality because potential costs or constraints prevent their display by low-quality individuals. Testing for potential physiological costs of ornaments is difficult, as this requires experimentally forcing individuals to produce and display elaborate ornaments. We use this approach to test whether a sexually selected trait is physiologically costly to male superb fairy-wrens (Malurus cyaneus). Male fairy-wrens molt from brown to blue breeding plumage at different times of the year, and females strongly prefer the few males that are blue early, during winter. We used short-acting testosterone implants to stimulate males to produce “early-blue” plumage and assessed costs during and after molt using a panel of physiological indices. Testosterone-implanted, T-males molted in winter and produced blue plumage 6 weeks before control-implanted, C-males. T-males molted while in lower body condition, tended to have lower fat reserves, and were more likely to be parasitized by lice. However, we detected no negative effects on immune function, blood parasites, exposure to stressors, or survival. Juvenile males never naturally display early-blue plumage, but we found no evidence for increased costs paid by juvenile T-males. Instead, juvenile T-males molted later than adult T-males, suggesting that age presents an absolute constraint on ornament exaggeration that cannot be fully overcome by testosterone treatment. Together, these small costs and large, age-related constraints may enforce signal honesty, and explain female preference for early-blue males.

Nutritional Physiology and Biochemistry of Dairy Cattle under the Influence of Heat Stress: Consequences and Opportunities.

Simple SummaryModern dairy cows have elevated internal heat loads caused by high milk production, and the effects of accumulating incremental heat are exacerbated when temperature and humidity increases in the surroundings. To shed this additional heat, cows initiate a variety of adaptive mechanisms including increased respiration rate, panting, sweating, reduced milk yield, vasodilatation, and decreased reproductive performance. Hormonal changes based on reciprocal alterations to the energetic metabolism are particularly accountable for reduced efficiency of the dairy production under the heat stress. As animals experience negative energy balance; glucose, which is also a precursor of milk lactose, becomes the preferential energy fuel. In the absence of proper mitigations, heat stress possesses potential risk of economic losses to dairy sector. Besides physical measures for the timely prediction of the actual heat stress coupled with its proper amelioration, nutritional mitigation strategies should target modulating energetic metabolism and rumen environment.Higher milk yield and prolificacy of the modern dairy cattle requires high metabolism activities to support them. It causes high heat production by the body, which coupled with increasing environmental temperatures results in heat stress (HS). Production, health, and welfare of modern cattle are severely jeopardized due to their low adaptability to hot conditions. Animal activates a variety of physiological, endocrine, and behavioral mechanisms to cope with HS. Traditionally, decreased feed intake is considered as the major factor towards negative energy balance (NEBAL) leading to a decline in milk production. However, reciprocal changes related to insulin; glucose metabolism; failure of adipose mobilization; and skeletal muscle metabolism have appeared to be the major culprits behind HS specific NEBAL. There exists high insulin activity and glucose become preferential energy fuel. Physiological biochemistry of the heat stressed cows is characterized by low-fat reserves derived NEFA (non-esterified fatty acids) response, despite high energy demands. Besides these, physiological and gut-associated changes and poor feeding practices can further compromise the welfare and production of the heat-stressed cows. Better understanding of HS specific nutritional physiology and metabolic biochemistry of the dairy cattle will primarily help to devise practical interventions in this context. Proper assessment of the HS in cattle and thereby applying relevant cooling measures at dairy seems to be the basic mitigation approach. Score of the nutritional strategies be applied in the eve of HS should target supporting physiological responses of abatement and fulfilling the deficiencies possessed, such as water and minerals. Second line of abatement constitutes proper feeding, which could augment metabolic activities and synergizes energy support. The third line of supplemental supports should be directed towards modulating the metabolic (propionates, thiazolidinediones, dietary buffers, probiotics, and fermentates) and antioxidant responses (vitamins). Comprehensive understanding of the energetic metabolism dynamics under the impact of incremental heat load and complete outlook of pros and cons of the dietary ameliorating substances together with the discovery of the newer relevant supplementations constitutes the future avenues in this context.

Egalitarian mixed-species bird groups enhance winter survival of subordinate group members but only in high-quality forests

Only dominant individuals have unrestricted access to contested resources in group-living animals. In birds, subordinates with restricted access to resources may respond to intragroup contests by acquiring extra body reserves to avoid periods of food shortage. In turn, higher body mass reduces agility and increases predation and mortality risk to subordinates. Birds often live in hierarchically organized mixed-species groups, in which heterospecific individuals are considered to substitute for conspecifics as protection against predators at a significantly reduced competition cost. Crested tits (Lophophanes cristatus) and willow tits (Poecile montanus) form mixed-species groups during the non-reproductive season that typically exhibit a nearly linear dominance hierarchy (‘despotic’ social structure) in which the highest ranking male willow tit is fourth in the overall hierarchy after the dominant male, female and subordinate juvenile crested tit, respectively. Much less frequently, ‘egalitarian’ dominance structures occur in which the adult willow tits rank second and the hierarchy is less steep, or linear. We present a rare long-term data set in which egalitarian flocks are common enough to assess the consequences of this simple change in hierarchy structure as well as a potential driver of the pattern. A comparison of individuals in the despotic mixed-species groups revealed a strong negative correlation between subcutaneous fat stores and dominance rank in the interspecific dominance hierarchy, whereas in egalitarian groups, subordinate willow tits had significantly lower fat reserves and they foraged in safer parts of the canopy than willow tits in despotic groups. Moreover, egalitarian groups exhibited markedly less within-group aggression, higher group cohesion and improved winter survival in both tit species. However, winter survival of birds in egalitarian groups was impaired relative to despotic groups in forests recently affected by industrial forestry. This suggests that the more egalitarian bird societies may best be adapted to less-disturbed environments.

Fuelling strategies differ among juvenile Sedge and Reed Warblers along the eastern European flyway during autumn migration

In this study, we investigated fattening strategies of juvenile Sedge and Reed Warblers during their autumn migration. We analysed fat scores of birds captured at five ringing sites situated between the southern Baltic Sea coast and Asia Minor. In Eastern Europe these two species had similarly low fat reserves. Their fat load increased in the Balkans. Remarkable differences between the species were noted in Asia Minor, where fat reserves of Sedge Warblers were more than two-fold higher compared to Reed Warblers. As high as 90% of Sedge and only 30% of Reed Warblers captured in Asia Minor had the potential capability to cross the Mediterranean Sea in one non-stop flight. Moreover, two-thirds of those Sedge Warblers were able to continue their long flight without refuelling and reach the southern edge of the Sahara desert, while in Reed Warblers only 6% of individuals were potentially able to use the same strategy. The results of the study show clear differences in potential flight ranges of the studied species, revealing different fattening strategies of the Sedge and Reed Warbler in the Balkans and Asia Minor.

Does intraspecific competition facilitate age separation in timing of southward migration in waders?

In many Palaearctic wader species there is a clear separation in the timing of adult and juvenile southward migration. This phenomenon is traditionally explained by the selection on adults to depart early from breeding grounds and necessity of juveniles to prepare longer for migration. In this study we hypothesize that late departure from natal grounds may also be adaptive for juveniles, as it allows them to avoid intensified interference competition at stopover sites with adult, usually more dominant conspecifics. To test this hypothesis we analysed long-term data on stopover behaviour of juvenile wood sandpipers (Tringa glareola) staying at a central Polish stopover site under varying levels of competition from adult birds. The results clearly indicated that juveniles were highly disadvantaged by the simultaneous presence of adults at the same staging site, as under intense competition from older conspecifics they refuelled more slowly and attained lower fat reserves. It was also found that juveniles which were forced to compete with adults left the site quickly and possibly searched for more favourable staging places. All these imply that delayed departure from natal grounds may be adaptive for juvenile waders, allowing them to mismatch the timing of their first migration with the peak of adult passage and, thus, reduce the negative consequences of intraspecific competition during migration.

Season and reproductive status rather than genetic factors influence change in ewe weight and fat over time 2. Spline analysis of crossbred ewes

The success of slaughter lamb enterprises is heavily influenced by the ability of the breeding ewe to produce a lamb annually across variable environments. It has been shown that by maintaining heavier weight and condition across the annual production cycle producers can make significant improvements in maternal performance. This paper follows on from a previous analysis of crossbred ewes within the Maternal Central Progeny Test and examines the potential to select for reduced fluctuation in weight and fat across the production cycle. A cubic spline model was fitted to the weight and fat score data from the first three parities of 2688 first-cross ewes. The analysis partitioned the influence of environment, reproduction and genetic effects on the shape of the weight and fat score splines across three parities. Yearly and seasonal variation in feed supply and the demands of raising a lamb are the major influences on fluctuations in the weight and fat score of the breeding ewe. The genetic effects were constant across time with 98 and 92% of the genetic variation for weight and fat, respectively, associated with the spline’s intercept. In agreement with the findings of the first paper of the series it can be concluded that genetic lines do not re-rank for weight or fat score over time. The influence of sire breed on weight and fat score was constant across time with sire breeds fluctuating in parallel across time. As a result it is concluded that to avoid low fat reserves and the subsequent low fertility during the ‘tough’ periods, selection to improve ewe body condition could be made at any time and under any environmental conditions.

Two major autumn migration strategies of Willow Warblers Phylloscopus trochilus in the eastern Mediterranean Basin

Willow Warblers Phylloscopus trochilus use two major migration strategies in the eastern Mediterranean Basin to overcome the sea barrier. The first is to cross the Mediterranean Sea after intensive fat refuelling and land on the shores of Egypt or Libya. The second strategy traverses the sea barrier using shortcuts or bypassing it through Israel. We show that Willow Warblers bypassing the Mediterranean Sea through Israel arrive with low fat reserves and low average body mass. Their body mass increased in suitable stopover sites. There was no significant gradient of body mass along a north–south axis in Israel. Our results indicate that Willow Warblers passing through Israel have a different endogenous plan of fat accumulation than the birds that cross the sea. The first migration strategy may allow Willow Warblers a staged crossing of the Sahara Desert without foraging, while the second implies an intermittent crossing with foraging. We suggest that Willow Warblers may cross the east side of the Sahara Desert in short flights with foraging during stopovers.

Nutritional status and body composition are already affected before oncology treatment in ovarian cancer.

Poor nutritional status is a common problem among ovarian cancer patients. In order to detect changes in nutritional status and body composition this study investigates anthropometrical and biochemical parameters among these patients. This study included women with ovarian cancer and woman without cancer. Body composition was assessed by bioelectrical impedance analysis (BIA), anthropometrically, and with DXA scan, and total serum protein, albumin, transferrin, hemoglobin, hematocrit levels and total lymphocyte count was also measured. Data from DXA scan and body composition as assessed by BIA was collected from thirty-one women. Student t-test was used to compare differences in means between groups. This study included 120 women, 57 with ovarian cancer and 63 with benign tumors. Both groups of women were overweight. Body fat by skin-fold thickness, arm circumference, serum albumin, total lymphocytes count, as well as transferrin levels were significantly lower in the ovarian cancer group (p<0.05). Ovarian cancer women had lower fat reserves by skin-fold thickness and lower serum proteins even though they were overweight. However, further studies need to use a body composition assessment on all subjects to confirm these results.

Lower Carnitine Plasma Values from Malnutrition Cancer Patients

Understanding the consequences of cancer for energy metabolism is required in order to define strategies that both prevent and treat malnutrition. Carnitine is essential for lipid energy metabolism. The objective of this study was to assess presurgical plasma carnitine levels in cancer patients and their association with dietary intake, anthropometry, bioelectrical impedance, indirect calorimetry, plasma amino acid levels, and urinary carnitine and nitrogen values. This was a prospective study in which two groups were randomly selected: one consisting of esophageal and gastric cancer patients (n = 24) and the other of healthy volunteers (control group, n = 12). Average plasma and urinary carnitine values ranged from 60 to 80 μM and 78 to 124 μM, respectively, in both groups, with no significant difference between them. Moreover, methionine and lysine levels, as well as resting energy expenditure, did not differ between cancer patients and controls. Plasma free carnitine levels, however, were significantly lower in cancer patients, 80 % (p < 0.05) of whom had deficient urinary carnitine excretion, insufficient dietary protein intake, and low body fat reserves. Although cancer patients had carnitine deficiency and lower carnitine stores, these did not affect resting energy expenditure, total food intake, or plasma lysine and methionine levels.

Hemoglobin concentrations in waders vary with their strategies of migration: A comparative analysis

The aim of this study was to determine whether blood oxygen capacity of waders varies with respect to migration at both inter-specific and individual level. To verify this hypothesis we measured hemoglobin concentration in 875 waders from 14 species during their autumn migration through central Poland. In most of the species we found an increase in the hemoglobin levels along with increasing fat loads during the stopover period, which suggests that individual birds are able to elevate their oxygen-carrying capacity of blood prior to departure on a migratory flight. Positive relationship between hemoglobin concentrations of waders and their fat loads was confirmed at the inter-specific level by the comparative analysis of independent contrasts. Comparative analysis also demonstrated that hemoglobin concentrations were positively related with theoretical flight range and mean refueling rate during stopovers. The results indicate that species traveling according to the strategy of energy-minimization (short-distance migrants, low fat reserves, low refueling rates) have lower blood oxygen capacity in comparison to time-selected species (long-distance migrants, high fat reserves, high refueling rates). It remains uncertain whether high hemoglobin levels in long-distance migrants are a fixed evolutionary trait or a temporal physiological adaptation associated with carrying considerable fat load.

Adaptive management of body mass by Siberian jays

A profusion of theoretical and empirical studies has successfully explored the issue of adaptive management of body mass by small birds threatened with both starvation and predation. In addition to diurnal body mass cycles, body mass tends to increase with either poorer mean conditions or more variable conditions, such as those often experienced during winter. In many species, individual dominance status will affect access to food and predation risk, and is therefore predicted to influence patterns of optimal body mass further. We investigated body mass regulation via repeated measurements without capture in groups of Siberian jays, Perisoreus infaustus , during autumn. As predicted, body mass of individuals increased throughout the day and towards the winter and was higher during colder periods. Jay body mass was also correlated with wind chill conditions 23 h before. This makes sense since conditions 24 h earlier were a better predictor of current conditions than conditions either 12 or 48 h earlier. Dominant birds (i.e. breeders) that were large carried relatively lower fat reserves than large subordinate individuals. The opposite was true for morphologically small birds. Together this suggests tighter requirements for individual variation in mass for dominant breeders in these groups. Our findings in this food-hoarding corvid are in general agreement with models and results concerning much smaller birds.

Measuring Animal Welfare within a Reintroduction: An Assessment of Different Indices of Stress in Water Voles Arvicola amphibius

Reintroductions are an increasingly common conservation restoration tool; however, little attention has hitherto been given to different methods for monitoring the stress encountered by reintroduced individuals. We compared ten potential measures of stress within four different categories (neuroendocrine, cell function, body condition and immune system function) as proxies for animal welfare in water voles being reintroduced to the Upper Thames region, Oxfordshire, UK. Captive-bred voles were assessed pre-release, and each month post-release for up to five months. Wild-born voles were captured in the field and assessed from two months post-release. Plasma corticosteroid, hydration and body condition of captive-bred voles differed between their pre-release measures and both their first (“short-term”) recapture, and their final recapture (“long-term” release), however only body condition and immunocompetence measured using the Nitroblue Tetrazolium (NBT) test were significantly different post-release between the first and last recaptures. Captive-bred animals had lower fat reserves, higher weight/length ratios and better immunocompetence (NBT) than did wild-born voles. Captive-bred males had higher ectoparasite burdens compared to wild-born males and, as reintroduction site quality decreased, became less hydrated. These observations indicate that some methods can identify changes in the stress response in individuals, highlighting areas of risk in a reintroduction programme. In addition, a single measure may not provide a full picture of the stress experienced; instead, a combination of measures of different physiological systems may give a more complete indication of stress during the reintroduction process. We highlight the need to monitor stress in reintroductions using measures from different physiological systems to inform on possible animal welfare improvements and thus the overall success rate of reintroductions.

Born to be bee, fed to be worker? The caste system of a primitively eusocial insect.

IntroductionPrimitively eusocial halictid bees are excellent systems to study the origin of eusociality, because all individuals have retained the ancestral ability to breed independently. In the sweat bee Halictus scabiosae, foundresses overwinter, establish nests and rear a first brood by mass-provisioning each offspring with pollen and nectar. The mothers may thus manipulate the phenotype of their offspring by restricting their food provisions. The first brood females generally help their mother to rear a second brood of males and gynes that become foundresses. However, the first brood females may also reproduce in their maternal or in other nests, or possibly enter early diapause. Here, we examined if the behavioural specialization of the first and second brood females was associated with between-brood differences in body size, energetic reserves and pollen provisions.ResultsThe patterns of variation in adult body size, weight, fat content and food provisioned to the first and second brood indicate that H. scabiosae has dimorphic females. The first-brood females were significantly smaller, lighter and had lower fat reserves than the second-brood females and foundresses. The first-brood females were also less variable in size and fat content, and developed on homogeneously smaller pollen provisions. Foundresses were larger than gynes of the previous year, suggesting that small females were less likely to survive the winter.ConclusionsThe marked size dimorphism between females produced in the first and second brood and the consistently smaller pollen provisions provided to the first brood suggest that the first brood females are channelled into a helper role during their pre-imaginal development. As a large body size is needed for successful hibernation, the mother may promote helping in her first brood offspring by restricting their food provisions. This pattern supports the hypothesis that parental manipulation may contribute to promote worker behaviour in primitively eusocial halictids.

Effect of the backfat thickness of sows in late pregnancy on the composition of colostrum and milk

Abstract. The aim of the work was to determine the effect of the condition of the sows in high pregnancy, being expressed by fat reserves and body weight, and of lactation period on chemical composition and energy content as well as physical and cytological parameters of colostrum and milk of the sows. The studies were conducted with 100 sows (PLW × PL), classified into the groups according to backfat thickness: I – (P2 + P4)/2&gt;20 mm and II – (P2 + P4)/2≤20 mm. The experiment was performed since 104th day of pregnancy till weaning of piglets after 21-day lactation. Fatness (points P2 and P4) and their changes during the periods: high pregnancy – parturition – weaning as well as physical and cytological parameters and colostrum and milk composition were examined. Domination of fatness in highly pregnant sows from group I vs. II was maintained during parturition and weaning (P≤0.001). Any effect of the sow condition on colostrum and milk quality was not found. In case of lower fat reserves in sows (group II vs. I) only lower fat content in colostrum and its lower energy content (by 16.3 % and 4.9 %, respectively), was found. For the majority of parameters no significant differences between the two groups were found. Only the bodyweight at weaning in group II, despite smaller number of piglets in the litter, was found to be significantly lower.

Using Automated Flight Mills to Manipulate Fat Reserves in Douglas-fir Beetles (Coleoptera: Curculionidae)

Because current techniques for quantifying fat, the main fuel used for flight in insects, are destructive, researchers are limited to only one direct measure of fat per specimen. This limitation is problematic for studies aimed at assessing whether fat loss through flight influences subsequent behavioral activity. To overcome this problem, we used body volume, body mass, emergence day, and brood density as parameters in a multiple regression model to predict initial fat levels in female Douglas-fir beetles, Dendroctonus pseudotsugae Hopkins, on emergence from the host. The model explained 54% of the variation in fat reserves as determined by Soxhlet extraction with petroleum ether. Treatments of 30-1,380 min of flight on rotary flight mills were used to establish the relationship between flight and fat reserves. Using a model that incorporated estimated initial fat levels, as well as time spent in flight and time in nonflight activities on the flight mills, we found that 6 h of flight decreased fat by approximately 50%. Flight activity and nonflight activity did not differ significantly in terms of their effect on fat reserves. Individual beetles with high initial fat content flew longer and faster on flight mills than beetles with low initial fat reserves. Our study shows how researchers can manipulate fat levels in bark beetles and other insects through flight, thereby opening the door to using these manipulations in behavioral studies.