Short‐term fitness benefits of physiological integration in the clonal herb Hydrocotyle peduncularis

Abstract We test whether physiological integration enhances the short‐term fitness of the clonal herb Hydrocotyle peduncularis (Apiaceae, R. Brown ex A. Richards) subjected to spatial variation in water availability. Our measures of fitness and costs and benefits are based on the relative growth rate of fragmented genets. Physiological integration over a gradient in soil moisture resulted in a highly significant net benefit to genet growth of 0.015 g g^?1 day^?1. This net benefit represents a significant enhancement of the average fitness of fragmented genets spanning the moisture gradient relative to the average of those growing in homogeneous moist or dry conditions. Sections of genet fragments growing in dry conditions in spatially heterogeneous treatments had significantly higher growth than the sections they were connected to that were growing in moist conditions. Within fragments, older (parent) sections growing in moist conditions experienced significant costs from connection to younger (offspring) sections growing in dry conditions. In contrast, offspring sections with ample water did not experience any costs when connected to parent sections growing in dry conditions. However, the net benefit of physiological integration was similar for parent and offspring sections, suggesting that parent and offspring sections contributed equally to the net benefit of physiological integration to genet growth and short‐term fitness.     

Influence of light and nitrate assimilation on the growth strategy in clonal weed <Emphasis Type="Italic">Eichhornia crassipes</Emphasis>

We studied as to how the inter-connected modular architecture of clonal Eichhornia crassipes allows nutrient to transfer from established ramets to developing ramets, and nitrate translocation within clonal system and how such a strategy may play an important role in successful establishment and expansion of this clonal plant. Using this stoloniferous E. crassipes as a model, we studied the effects of light and nitrate availability on growth and nitrate assimilation in inter-connected parent and offspring ramets. Our results showed that increase in light and nitrate availability significantly increased growth rate of the whole clonal fragments and reproduction of offspring ramets in E. crassipes. In addition, increases in nitrate reductase (NR) activity and glutamine synthetase (GS) activity were observed in both parent and offspring ramets with increase in light density and nitrate supply. We also found that nitrate translocation is greater in offspring ramets than in parent ramets under abundant light and nitrate environment in this fast-growing clonal plant. Consequently, majority of nitrate assimilation in offspring ramets is beneficial to the growth of whole clonal system, as indicated by a close correlation between nitrate assimilation in offspring ramets and RGR of whole clonal fragments. We strongly contend that nitrate translocation and assimilation within clone system is important for efficient utilization of nitrogen in alien clonal plant E. crassipes during establishment and expansion, and thus for increase in its invasiveness in natural water columns.     

The effect of temperature and water quality on the in vitro development and survival of Asellus aquaticus (Crustacea: Isopoda) eggs

The rate of development and degree of survival of Asellus aquaticus eggs outside the marsupium of ovigerous females are affected by water quality and temperature. Eggs were maintained in polluted river water and relatively clean canal water. Developmental rates increase with increased temperature, but survival decreases. Eggs from polluted site ovigerous females survive better in clean water than in polluted water. Eggs from clean site ovigerous females maintained in polluted water have significantly lower survival rates than eggs from the polluted site at all temperatures tested. The developmental rate of clean site eggs is increased significantly in polluted water at 10–25 °C, possibly as a response to the stress imposed upon them.It is suggested that the method outlined might form the basis of a useful bioassay technique for measuring water quality.     

Hot and not‐so‐hot females: reproductive state and thermal preferences of female Arizona Bark Scorpions (Centruroides sculpturatus)

For ectotherms, environmental temperatures influence numerous life history characteristics, and the body temperatures (T_b) selected by individuals can affect offspring fitness and parental survival. Reproductive trade‐offs may therefore ensue for gravid females, because temperatures conducive to embryonic development may compromise females' body condition. We tested whether reproduction influenced thermoregulation in female Arizona Bark Scorpions (Centruroides sculpturatus). We predicted that gravid females select higher T_b and thermoregulate more precisely than nonreproductive females. Gravid C. sculpturatus gain body mass throughout gestation, which exposes larger portions of their pleural membrane, possibly increasing their rates of transcuticular water loss in arid environments. Accordingly, we tested whether gravid C. sculpturatus lose water faster than nonreproductive females. We determined the preferred T_b of female scorpions in a thermal gradient and measured water loss rates using flow‐through respirometry. Gravid females preferred significantly higher T_b than nonreproductive females, suggesting that gravid C. sculpturatus alter their thermoregulatory behaviour to promote offspring fitness. However, all scorpions thermoregulated with equal precision, perhaps because arid conditions create selective pressure on all females to thermoregulate effectively. Gravid females lost water faster than nonreproductive animals, indicating that greater exposure of the pleural membrane during gestation enhances the desiccation risk of reproductive females. Our findings suggest that gravid C. sculpturatus experience a trade‐off, whereby selection of higher T_b and increased mass during gestation increase females' susceptibility to water loss, and thus their mortality risk. Elucidating the mechanisms that influence thermal preferences may reveal how reproductive trade‐offs shape the life history of ectotherms in arid environments.     

Maternally transmitted foetal <Emphasis Type="Italic">H19</Emphasis> variants and associations with birth weight

This study was designed to test the hypothesis that polymorphic variation in maternally transmitted foetal H19 alleles is associated with offspring size at birth and alterations in maternal glucose concentrations in pregnancy. Inferred parent of origins of transmitted alleles from 13 haplotype tag SNPs in the H19 gene region from 845 family (mother, partner, offspring) trios from the prospective Cambridge Baby Growth Study and 315 trios from the retrospective Cambridge Wellbeing Study cohorts were tested for association with offspring size at birth measures, as well as maternal glucose concentrations 1 h after a glucose load at week 28 of pregnancy. The foetal rs2071094 allele inherited from the mother was associated with increased birth weight (p = 0.0015) adjusted for gestational age, parity and sex. In the Cambridge Baby Growth Study it was also associated with increased head circumference (p = 0.004), length (p = 0.017) and sum of skinfold thicknesses (p = 0.017) at birth. In contrast to these results there was no association between offspring birth weight and either the maternal rs2071094 genotype or the foetal allele from the father. None of the foetal alleles or maternal genotypes were associated with maternal glucose concentrations, neither were there any other associations with offspring birth weight. In conclusion, consistent with imprinting, common polymorphic variation in foetal H19 alleles transmitted only from the mother are associated with birth weight and other markers of size at birth. Polymorphic variation in H19 is not associated with significant changes in maternal glucose tolerance in the third trimester of pregnancy.     

Effects of salinity and light on biomass and growth of <Emphasis Type="Italic">Vallisneria americana</Emphasis> from Lower St. Johns River,FL, USA

A mesocosm study was conducted to determine the effects of variable salinity and light on Vallisneria americana Michx. (wild celery) and associated algal community components in the lower St. Johns River, Florida. Fifteen centimeter diameter intact plant plugs were collected from the LSJR in March 2001 and transported to mesocosm facilities in Lafayette, Louisiana. A factorial experimental design was used consisting of three salinity levels (1, 8, and 18 ppt), three light levels (0, 50, and 90% shading), and three replicate mesocosms of each for a total of 27 mesocosms. The experiment consisted of a 4-week acclimation period followed by a 5-month treatment period. V. americana responded negatively to increased salinity. Although V. americana survived 8 ppt salinity, growth was limited. At 18 ppt, almost all V. americana aboveground biomass had perished within 10 weeks, but when salinity was lowered back to 1 ppt, approximately 20% of the aboveground biomass recovered within the following 10 weeks. At midtreatment harvest, light did not affect V. americana biomass directly (P = 0.8240), but by final harvest (20 weeks) light affected belowground biomass (P < 0.0014). Both salinity and light affected algal growth. Macroalgae dominated 1 ppt salinity treatments in ambient light, but phytoplankton dominated 8 and 18 ppt salinity treatments in ambient light. Algal communities were greatly inhibited by 90% shading. While salinity directly impacted V. americana growth and survival, light effects were less direct and involved algal community associations.     

Effects of photoperiod and diet on diapause tendency,maturation and fecundity in Harmonia axyridis (Coleoptera: Coccinellidae)

The effects of photoperiodic conditions of larval development and adult maturation (L : D = 12 : 12 vs. 18 : 6) and different diets (sugar solution, frozen eggs of Sitotroga cerealella, different numbers of aphids Myzus persicae, and their combinations) on survival, reproductive maturation and fecundity of Harmonia axyridis were studied in laboratory conditions. The fundamental aim of the work was to distinguish between cue effect of diet (neurohormonal triggering of reproduction) and direct effect of diet (nutritional maintenance of reproduction). When adults were kept under short‐day conditions, the proportion of ovipositing females decreased and the duration of the pre‐oviposition period increased. Moreover, a strong reaction to the direction of changes in the day length was demonstrated: when larvae and pupae developed at long day and adults were transferred to short day, the proportion of ovipositing females was much lower than in individuals that were permanently kept under short‐day conditions. The percentage of ovipositing females, the rate of their reproductive maturation and the average daily fecundity gradually increased in the following succession of diets: ‘sugar + 5 aphids per day < sugar + eggs < sugar + eggs + 5 aphids per day < sugar + 100 aphids per day’. However, dissection showed that most of the non‐laying females fed on these diets (particularly those kept under long‐day conditions) have started reproductive maturation, while even first stages of oogenesis were not found in females fed on sugar solution alone. We conclude that cue effect of diet (reproductive activation) can be achieved almost independently of the number of prey consumed, while nutritional effects (the rate of reproductive maturation and fecundity) are sensitive both to the quality and quantity of food.     

Human urine is an excellent liquid waste for the culture of fish food organism, Moina micrura

With a view to converting human urine into bio-wealth in the form of zooplankton, the nutrient potentials of liquid wastes (0.11 mL L⁻¹)—(i) human urine (♂), (ii) cow urine, (iii) human–cow mixed urine or some solid wastes (0.11 g L⁻¹): (iv) vermi-compost, (v) cow dung, (vi) poultry droppings and (vii) mixed wastes (vermi-cow-poultry)—were evaluated for the mass culture of zooplankton Moina micrura in 24 outdoor tanks (4500 L) in triplicate treatments using life table as indicator during the period of October–December, 2005. Neonates of Moina micrura held in the treatment with human urine started reproduction at least 4 days earlier than other solid wastes tested. Total number of Moina micrura enumerated in the culture tank, related with offspring production per life span, was maximum in case of human urine treatment, followed by human–cow mixed urine, cow urine, vermin-compost, poultry droppings, mixed wastes (vermin–cow–poultry), cow dung and control treatments. The relationship between the total offspring production per female per life span and the nitrogen content of water in different treatments implied that human urine was an excellent liquid waste that can be used for the mass production of zooplankton Moina micrura required for larval and post larval rearing of commercial fishes.     

Sexual conflict and consistency of offspring desertion in Eurasian penduline tit <Emphasis Type="Italic">Remiz pendulinus</Emphasis>

Background  

The trade-off between current and future parental investment is often different between males and females. This difference may lead to sexual conflict between parents over care provisioning in animals that breed with multiple mates. One of the most obvious manifestations of sexual conflict over care is offspring desertion whereby one parent deserts the young to increase its reproductive success at the expense of its mate. Offspring desertion is a wide-spread behavior, and its frequency often varies within populations. We studied the consistency of offspring desertion in a small passerine bird, the Eurasian penduline tit Remiz pendulinus, that has an extremely variable breeding system. Both males and females are sequentially polygamous, and a single parent (either the male or the female) incubates the eggs and rears the young. About 28–40% of offspring are abandoned by both parents, and these offspring perish. Here we investigate whether the variation in offspring desertion in a population emerges either by each individual behaving consistently between different broods, or it is driven by the environment.     

Offspring growth, survival and reproductive success in the bank vole: a litter size manipulation experiment

To estimate the optimality of brood size, it is essential to study the effects of brood size manipulation on offspring survival and reproductive success. Moreover, testing the generality of the hypothesis of reproductive costs requires experimental data from a diversity of organisms. Here I present data on the growth, survival and reproductive success of bank vole Clethrionomys glareolus individuals from manipulated litters. Furthermore, the survival of mothers whose litter size was manipulated was studied. At weaning, the mean weight of pups from enlarged litters was lower and from reduced litters higher compared to control litters. After winter, at the start of the breeding season, individuals from enlarged litters, especially males, were still lighter than individuals from the other two treatments. Litter enlargements did not increase the number of reproducing female offspring per mother, nor did the litter sizes of female offspring differ between treatments. There were no differences between treatments in winter survival of offspring after weaning, but among female offspring, weaning weight explained the survival probabilities over winter. A higher weight of females at winter determined the probability of starting to reproduce in spring. The survival of mothers did not seem to be influenced by litter manipulation performed the previous year. According to the results, mothers nursing enlarged or reduced litters do not gain any fitness benefits in terms of number of offspring surviving to breeding. The results are consistent with the majority of experiments conducted in birds, which have found costs of enlarged brood appearing as offspring trade-offs rather than parent trade-offs. Received: 14 December 1997 / Accepted: 1 March 1998     

Ovarian response to resource availability in female Rhagoletis indifferens

Fitness trade‐offs in behavioural ecology theory suggest that the costs associated with dispersal can impact reproductive output, but evidence of dispersal‐reproduction trade‐offs is often lacking. We present evidence of Rhagoletis indifferens Curran (Diptera: Tephritidae) developing its egg load in response to host availability [Prunus avium L. (Rosaceae)] and link this to our previous work on flight behaviour through the common methodology of these two studies. We replicated the study design from the flight mill experiment, such that females were maintained in one of six possible treatments combining two factors: social interactions (crowded vs. isolated) and resources (food = food only; leaf = food + leaf; and cherry = food + leaf + fruit), and then dissected the females to determine egg load. Egg counts varied significantly with ‘crowded’ females and those in the ‘cherry’ resource treatments producing the most mature eggs. Although the average mature egg count for females from the ‘leaf’ and ‘food’ resource treatments was similar, these two groups differed in the proportion of females that produced no mature eggs at all. No significant interaction terms between the factors tested were generated. We conclude that the effect of social interactions and resources on the maturation of eggs is additive in R. indifferens. These results support those of an earlier flight mill experiment and provide evidence that egg load may trade off with dispersal ability in R. indifferens.     

The Foraging Behavior of <Emphasis Type="Italic">Lysiphlebus fabarum</Emphasis> (Marshall), a Thelytokous Parasitoid of the Black Bean Aphid in Iran

A series of laboratory experiments examined the foraging behavior of a thelytokous strain of Lysiphlebus fabarum (Marshall), a strongly proovigenic parasitoid of Aphis fabae Scopoli, in Iran. Females use chemical camoflage to forage undisturbed in ant-tended aphid colonies and solicit honeydew from aphids in the manner of ants. Rates of oviposition are very low (∼ 1.2 eggs / h) despite many aphid encounters and persistent ovipositor probing which appears to prime aphids for subsequent honeydew solicitation. Starved females spent 3.6 times longer in host patches (leaf disks with 15 2nd–3rd instar A. fabae) than did females sated on honey, and 40% of this time was spent soliciting honeydew. Five d-old females spent longer in patches than did one d-old females, and parasitized three times as many aphids. A 24 h pre-trial foraging experience did not reduce mean egg load significantly compared to a one h experience, but was sufficient to reduce patch residence time and number of aphids parasitized. Wasps reared under short day conditions (L:D = 10:14) were more pessimistic foragers (remained longer in patches and parasitized more aphids) than females raised under long days (L:D = 16:8). Wasps that encountered aphids previously parasitized by conspecifics began to superparasitize and remained longer in patches than females that encountered only unparasitized aphids. Encounters with other females had no effect on foraging behavior, possibly because cuticular camoflage interferes with conspecific recognition. The exceptionally low oviposition rate of this wasp may reflect a life history in which individual fitness has evolved to be strongly dependent on continued ant attendance throughout the period of progeny development.     

Distribution,biology, and ecology of the deep‐water squat lobster Galacantha diomedeae (Crustacea: Decapoda: Galatheoidea: Munidopsidae) in the Mexican Pacific

During deep‐water exploratory surveys in the Mexican Pacific, 134 specimens of Galacantha diomedeae were collected between 1,035 and 2,136 m depth, below the Oxygen Minimum Zone. Greatest densities of G. diomedeae were observed between 1,300 and 1,600 m, with a maximum of 71 organisms per hectare at 1,318 m, and no clear bathymetric pattern of size distribution was detected. A total of 67 males, 43 ovigerous females, and 24 non‐ovigerous females were collected. The global sex ratio was 1:1, with some predominance of females shallower than 1,300 m and the opposite pattern at 1,300–1,600 m. Ovigerous females (carapace width [CW]=15.5?32.3 mm) were significantly larger than other females (CW = 5.1?29.9 mm), and females (including all females) were larger than males (CW = 6.0?29.9 mm). Among males and among all females, the growth coefficient was near 3 (Student's t test, males = 0.0027, all females = 0.0041; for both males and females, p > 0.05), indicating isometric growth. Ovigerous females were present all year, except in January, suggesting continuous reproduction. The observed low numbers of eggs (11–126), large egg sizes (2.07–2.77 mm), and advanced embryos at stage 5 are consistent with extended, lecithotrophic embryonic development with a reduced pelagic phase of the larvae. The relationship between ovigerous female size (N = 43) and number of eggs per female was marginally significant (y = 8.0474x–98.297; R² = 0.373), and there was no significant relationship between egg size and carapace size. There was no clear increase in egg size with embryonic development (phases 1–5). Individuals of G. diomedeae were found in a narrow range of environmental conditions, and mainly occupied oxic water (DO ≥0.5 ml/L) and sediments with intermediate to low organic carbon content.     

Climate change will alter amphibian‐mediated nutrient pathways: evidence from Rana temporaria tadpoles in experimental ponds

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Reproductive parameters of a captive colony of capuchin monkeys (<Emphasis Type="Italic">Cebus apella</Emphasis>) from 1984 to 2006

This paper presents the results of a demographic analysis of 22 years of data recorded on a colony of tufted capuchin monkeys (Cebus apella) in captivity at the CNR Primate Centre (Rome, Italy). Information is provided on reproduction, sex ratio, inter-birth interval (IBI), seasonality, and body weight. From 1984 to 2006, 46 live births were recorded. There were births in almost all months of the year, but a higher frequency was observed during spring and summer (71.1%). The sex ratio was 1:1 M:F for newborns and 1:1.06 M:F for surviving offspring. At birth, infants’ average weight was 238.13 ± 37.51 g, i.e. 250 ± 56.79 g for males and 231 ± 26.08 g for females. Age at first birth for females ranged from 4.9 to 7 years (n = 9), while males achieved first paternity between the ages of 5 and 9.2 years (n = 6). Only one pair of twins was recorded during this period. For females, the mean IBI was 17.88 ± 1.84 months, when they reared infants, and 12.70 ± 1.73 months, when they did not rear offspring. Infant mortality within the first 2 months was 28.3%.     

Familial longevity is characterized by high circadian rhythmicity of serum cholesterol in healthy elderly individuals

The biological clock, whose function deteriorates with increasing age, determines bodily circadian (i.e. 24h) rhythms, including that of cholesterol metabolism. Dampening of circadian rhythms has been associated with aging and disease. Therefore, we hypothesized that individuals with a familial predisposition for longevity have a higher amplitude circadian serum cholesterol concentration rhythm. The aim of this study was to investigate circadian rhythmicity of serum cholesterol concentrations in offspring of nonagenarian siblings and their partners. Offspring from nonagenarian siblings (n = 19), and their partners as controls (n = 18), were recruited from the Leiden Longevity Study. Participants (mean age 65 years) were studied in a controlled in‐hospital setting over a 24‐h period, receiving three isocaloric meals at 9:00 h, 12:00 h and 18:00 h. Lights were off between 23:00 h and 8:00 h. Serum total cholesterol (TC), HDL cholesterol (HDL‐C), non‐HDL‐C and triglycerides (TG) were determined every 30 min over a 24‐h period. Serum TC concentrations were higher during day than during night in offspring (5.2 vs. 4.7 mm , P < 0.001) and in controls (5.3 vs. 5.0 mm , P < 0.001). The difference in TC concentrations between day and night tended to be greater in offspring than in controls (0.5 vs. 0.3 mm , P = 0.109), reaching statistical significance in females (P = 0.045). Notably, the day–night serum differences in non‐HDL‐C were twofold greater in offspring than in controls (0.43 vs. 0.21 mm , P = 0.044) and most explicit in females (0.53 vs. 0.22, P = 0.078). We conclude that familial longevity is characterized by a high circadian rhythmicity of non‐HDL‐C in healthy elderly offspring from nonagenarian siblings.     

Aquatic grazers reduce the establishment and growth of riparian plants along an environmental gradient

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Life history and population dynamics of a tree species in tropical semi‐arid climate: A case study with Cordia oncocalyx

In semi‐arid climates, plant population dynamics are strongly influenced by the amount and temporal distribution of rainfall. We monitored a population of the tree species Cordia oncocalyx (Boraginaceae) for 24 months in the dry thorny woodland of semi‐arid northeastern Brazil, to investigate which life‐history traits allow this tree to be locally dominant. We used horizontal life tables and a Lefkovitch matrix and tested for relationships among demographic parameters of seedling, infant, juvenile, immature, virginile and reproductive ontogenetic stages with rainfall and canopy openness. Germination and recruitment occurred in the rainy months, and dry‐season mortality occurred only in seedlings (76% and 100%, first and second years, respectively) and infants (3% and 6%). Juveniles showed greater height growth under more open canopies (Spearman correlation coefficient = 0.24), suggesting that light availability influences growth. The population growth rate was λ = 1.0336, and the highest sensitivity occurred in the infant‐juvenile transition. Our results show light as a restrictive growth factor for plants in the juvenile stage and confirm the strong influence of rainfall on the dynamics of trees in a seasonally dry environment. The formation of a persistent seed bank with germination concentrated at the rainfall onset but spreading over the rainy season are strategies that hedge bets before establishment. The formation of a bank of infants, which can resume growth as soon as there is water, hedges bets after establishment. We attribute the positive population growth rate of Cordia oncocalyx to survival strategies allowing bet‐hedging both before and after establishment.     

Behavioral modifications lead to disparate demographic consequences in two sympatric species

Life‐history theory suggests species that typically have a large number of offspring and high adult mortality may make decisions that benefit offspring survival in exchange for increased adult risks. Such behavioral adaptations are essential to understanding how demographic performance is linked to habitat selection during this important life‐history stage. Though studies have illustrated negative fitness consequences to attendant adults or potential fitness benefits to associated offspring because of adaptive habitat selection during brood rearing, equivocal relationships could arise if both aspects of this reproductive trade‐off are not assessed simultaneously. To better understand how adaptive habitat selection during brood rearing influences demographics, we studied the brood survival, attendant parental survival, and space use of two sympatric ground‐nesting bird species, the northern bobwhite (hereafter: “bobwhite”; Colinus virgininanus) and scaled quail (Callipepla squamata). During the 2013–2014 breeding seasons, we estimated habitat suitability across two grains (2 m and 30 m) for both species and determined how adult space use of these areas influenced individual chick survival and parental risk. We found the proportion of a brood's home range containing highly suitable areas significantly increased bobwhite chick survival (β = 0.02, SE = 0.006). Additionally, adult weekly survival for bobwhite was greater for individuals not actively brooding offspring (0.9716, SE = 0.0054) as compared to brooding adults (0.8928, SE = 0.0006). Conversely, brood habitat suitability did not influence scaled quail chick survival during our study, nor did we detect a survival cost for adults that were actively brooding offspring. Our research illustrates the importance of understanding life‐history strategies and how they might influence relationships between adaptive habitat selection and demographic parameters.     

Comparing Behavioural Patterns of Thrips tabaci Lindeman on Leek and Cucumber

This study documents the behavioural repertoire of Thrips tabaci. Seventeen behavioural elements shown by adult females were videotaped, described and classified into seven behavioural categories. The comparison of thrips behaviour on leek and cucumber over 24 h (L:D = 16:8) revealed that on cucumber thrips spent significantly less time being inactive, but significantly more time with feeding resulting in significantly higher feeding damage compared to leek. Oviposition behaviour incidence and oviposition rate were somewhat, but not significantly lower on cucumber compared to leek. Sequences of leaf surface exploration lasted significantly longer on cucumber than on leek. Thrips females were as active during light as during dark periods. Our results show that T. tabaci females spend different amounts of time with resting, feeding and explorative behaviours on leek and cucumber, thus indicating differences in host use on these two crops.