History dependent effects on phenotypic expression of a newly emerged gene

In this study, we investigate the history dependence of the penetrance of a newly emerged gene. Penetrance is defined as the percentage of individuals with a given genotype who exhibit the phenotype associated with that particular genotype. Here, we used the glutamine synthetase gene and its mutants with lower fitness as model genes. They were introduced into host cells of Escherichia coli deprived of the gene, and their penetrance was measured using the host having a different history: either with or without glutamine starvation. Results show that for all genes tested, the value of penetrance was higher when they were introduced into the host cell without starvation than that when introduced into the starved cell, demonstrating the history dependence of the penetrance of a newly emerged gene. In addition, genes with lower fitness showed lower penetrance, and the effect of the difference in fitness on gene penetrance also depended on the history of the host cell.     

Adaptive evolution of newly emerged micro-RNA genes in Drosophila

How often micro-RNA (miRNA) genes emerged and how fast theyevolved soon after their emergence are some of the central questionsin the evolution of miRNAs. Because most known miRNA genes areancient and highly conserved, these questions can be best answeredby identifying newly emerged miRNA genes. Among the 78 miRNAgenes in Drosophila reported before 2007, only 5 are confirmedto be newly emerged in the genus (although many more can befound in the newly reported data set; e.g., Ruby et al. 2007;Stark et al. 2007; Lu et al. 2008). These new miRNA genes haveundergone numerous changes, even in the normally invariant maturesequences. Four of them (the miR-310/311/312/313 cluster, denotedmiR-310s) were duplicated from other conserved miRNA genes.The fifth one (miR-303) appears to be a very young gene, originatingde novo from a non-miRNA sequence recently. We sequenced these5 miRNA genes and their neighboring regions from a worldwidecollection of Drosophila melanogaster lines. The levels of divergenceand polymorphism in these miRNA genes, vis-à-vis thoseof the neighboring DNA sequences, suggest that these 5 genesare evolving adaptively. Furthermore, the polymorphism patternof miR-310s in D. melanogaster is indicative of hitchhikingunder positive selection. Thus, a large number of adaptive changesover a long period of time may be essential for the evolutionof newly emerged miRNA genes.     

The effects of decapitation and the influence of size and sex on diuresis in newly emerged mosquitoes

ABSTRACT. Diuresis in the newly emerged adult mosquito occurs in two phases, a short initial peak immediately after eclosion and a longer peak in the middle of day 1. The present work lends support to the view that the second phase of diuresis is controlled by a hormone which is either released from the head, or from the thorax under the control of the head, 3–4 h after eclosion. The influence of the head ceases to be effective some 9 h later. The rate of water loss is normally higher in unfed females than in unfed males. Whereas the higher rate of diuresis in females during the two peaks is a function of size, the higher rate in unfed females during the second and third day following eclosion is mostly a result of ovarian activity during this period.     

Contribution of dogs to white-tailed deer hunting success

Dogs (Canis familiaris) are used in hunting white-tailed deer (Odocoileus virginianus) in 10 North American jurisdictions. Although the practice is longstanding and controversial, the effects of dogs on the outcome of the hunt have rarely been studied. We evaluated the influence of dogs on recreational hunting of white-tailed deer based on long-term data from southeastern Ontario, Canada. Over 25 years, annual surveys of hunters were used to collect data on hunting effort and deer harvest from approximately 85 camps, roughly half of which had dogs. We investigated the relationship between harvest and 3 treatments (i.e., 0 dogs, 1 dog, and ≥2 dogs in camp), interactions with weather and deer density, and effects of neighboring camps. Dogs enhanced hunter success. We found no difference in deer encounter rates but, per unit effort, camps with ≥2 dogs harvested 0.013 (26%) more deer per hunter-day, missed 0.010 (23%) more deer per hunter-day, and wounded 0.002 (40%) more deer per hunter-day than camps without dogs. Conversely, camps without dogs saw, without shooting at, 0.033 (23%) more deer per hunter-day than camps with ≥2 dogs. These results are consistent with the idea that hunters with dogs are less selective. Hunters with dogs harvested more fawns per unit effort, but we found no difference in the harvest rate of older female deer. More precipitation, greater wind speed, lower temperatures and greater deer density improved harvest success but had no differential effect among dog treatments. Hunter success at camps with ≥2 dogs was less when neighboring camps also had ≥2 dogs. Because antlerless deer quotas are the principal means to control populations, increasing use of hunting dogs is unlikely to have substantial effects in managing overabundant deer. © 2012 The Wildlife Society.     

Hormonal regulation of cuticle extensibility in newly emerged adult blowflies

The cuticle of adult blowflies, Calliphora vicina, newly emerged from their puparial cases, is relatively inextensible. It becomes briefly more extensible at the time of air swallowing, when the body is inflated and the wings expanded. This plasticization is shown to be under the control of a blood-borne active factor which is indistinguishable from the tanning hormone, bursicon, in a number of ways. Cuticle plasticization is not, however, a consequence of the chemical events of tanning.     

Physiological development and dispersal ability of newly emerged Monochamus galloprovincialis

Novel associations between exotic pathogens and native insects may result in major ecological and economical losses. In Europe, Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae) is the only known vector of the exotic pine wood nematode Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle (Nematoda: Aphelenchoididae), the causal agent of pine wilt disease (PWD). Transportation of goods containing nematode‐infested beetles is the main pathway for the spread of the disease. In this scenario, management actions involving early detection and eradication are critical to stop further spread by the vector. Although dispersal of mature M. galloprovincialis has been successfully tracked using commercial baits and traps, dispersal ability of immature individuals is poorly understood. Sexual maturation and other physiological traits related to dispersal were studied for newly emerged M. galloprovincialis after different shoot‐feeding spans. Sexual maturation was complete after on average 12 (males) or 13 (females) feeding days. Monochamus galloprovincialis adults emerged with an average of 10% lipid and 23.8% (males) or 29.9% (females) pterothorax muscle content, and these percentages did not change significantly during shoot feeding. Microtomography images of wing muscle structures at different maturation stages confirmed these results. Emerged adults that were kept unfed survived an average of 12 days in the lab. The ability of unfed immature insects to fly through hostless terrain was studied by marking and releasing newly emerged insects from a crop area located up to 3 km away from two small pine stands. The longest flown distance recorded was 2 km. Fitted regressions indicated that immature insects could have travelled up to 3 109 m to reach the experimental stands. We found that M. galloprovincialis emerge with well‐developed thoracic muscles and energy reserves that enable them to sustain long flights over non‐forested areas. These findings should aid managers and policy makers in devising sound procedures in areas where the risk of introducing PWD is high.     

A circadian rhythm of locomotor activity in newly emerged Ceratophyllus sciurorum

Abstract Circadian rhythm in newly emerged individuals of the Red Squirrel ( Scuirus vulgaris ) flea C.s. sciurorum was studied in a constant environment, using an insect activity monitor. Trials were run over 7 days using two start times (08.00 and 17.00 hours). The results show that, regardless of start time, the fleas display a 24 h activity rhythm. The presence of a rhythm under constant conditions gives a strong indication that C. s.sciurorum has a self-sustaining clock which is started by disturbance and is most likely to be linked to host activity patterns.     

The effect of cold temperature exposure and long-day photoperiod on the termination of the reproductive diapause of newly emerged female Pissodes strobi (Coleoptera: Curculionidae)

Abstract

• 1 There is confusion in the literature concerning a possible reproductive diapause in the adult white pine weevil Pissodes strobi.
• 2 We evaluated the effects of temperature, photoperiod, feeding substrate and mating status on the sexual maturation and oviposition of female white pine weevils.
• 3 Less than 30% of female P. strobi became sexually mature and laid eggs without experiencing dormancy under a temperature regime of 2 °C for 4 weeks.
• 4 Among the females that experienced a cold temperature treatment after emergence, 80% laid eggs after dormancy when exposed to a long‐day (LD 16 : 8 h) photoperiod and 17.6% laid eggs when exposed to a short‐day (LD 8 : 16 h) photoperiod.
• 5 Significantly more eggs were laid by all the females (with and without a cold treatment) when subjected to a long‐day photoperiod compared with a short‐day photoperiod.
• 6 A period of cold temperature followed by exposure to a long‐day photoperiod with warmer temperatures is required to break reproductive diapause and to obtain a good oviposition response in female P. strobi.
• 7 This study reveals the existence of much intraspecific variation in the response of the white pine weevil to temperature and photoperiod with respect to the induction and termination of reproductive diapause.

     

Hierarchical Bayes estimation of hunting success rates with spatial correlations

A Bayesian hierarchical generalized linear model is used to estimate hunting success rates at the subarea level for postseason harvest surveys. The model includes fixed week effects, random geographic effects, and spatial correlations between neighboring subareas. The computation is done by Gibbs sampling and adaptive rejection sampling techniques. The method is illustrated using data from the Missouri Turkey Hunting Survey in the spring of 1996. Bayesian model selection methods are used to demonstrate that there are significant week differences and spatial correlations of hunting success rates among counties. The Bayesian estimates are also shown to be quite robust in terms of changes of hyperparameters.     

Factors influencing the hunting success of the predator: A model with sighthounds

Using microbiological criteria (the number of CFU in nose prints on agar medium), it has been shown that the proportion of individuals with a high CFU count is significantly higher among brown hares caught by sighthounds or exposed to immobilization stress than among shot hares. A hypothesis is proposed that metabolites of the body surface microflora in animals exposed to long-term stress account for their specific stress odor. Observations on wild hare coursing with the use of GPS tracking (1-s update rate) provide evidence that hunting success is not directly dependent on the absolute and relative coursing speeds, the number of sighthounds, and the distance, duration, and number of coursing episodes. An analysis has been performed of stress odor as a universal criterion allowing the predator to estimate the vulnerability of potential prey. Selective elimination of unhealthy (stressed) individuals by predators is a mechanism of natural selection for increased adaptation of populations and species to the effects of a broad spectrum of environmental factors.     

Duck hunter activity,success, and satisfaction on public hunting areas

Because hunting disturbance can influence local distribution of ducks and their availability to hunters, managers often limit access to hunting areas to improve hunting success and satisfaction. Few studies have quantified the effectiveness of public area access restrictions on duck hunter activity, harvest, or hunters' satisfaction with their hunting experience. We used a cross-over design over 6 consecutive hunting seasons (2008–2009 through 2013–2014) on State Wildlife Areas (SWAs) in northeastern Colorado, USA, to compare the effects of restricted hunting access regulations and regulations without these restrictions on duck hunter activity, harvest success, harvest levels, and satisfaction. We also considered effects of SWA types, duck abundance, temperature, precipitation, use of equipment by duck hunting parties, and, for hunter satisfaction, hunting success, hunting parties' satisfaction with ducks seen, habitat conditions, crowding from other hunters, and SWA regulations. The number of days when duck hunters had access to restricted properties was about half that on unrestricted properties, and unrestricted properties were used by about twice as many duck hunting parties, but the mean number of hunting parties per available hunting day and mean party size were similar under the 2 types of regulations. Most (56%) duck hunting parties did not bag any ducks; hunting success (harvest of ≥1 duck by a hunting party) was best explained by a model that included a regulation type × hunting season interaction, a SWA type × month interaction, hunter density the previous day, an index of hunter investment (number of decoys used and whether dogs and calls were used), and temperature. Successful hunting parties harvested 1.92 ± 1.60 (SD) ducks/hunter/day (range = 0.1–7.0); the best model predicting the number of ducks harvested per hunter in successful parties included a regulation type × hunting season interaction, a SWA type × month interaction, hunter density the previous day, an index of hunter investment, temperature, and precipitation. Overall satisfaction of duck hunting parties with a day's hunt averaged 3.62 ± 1.20 based on a rank scale of 1 (very unsatisfied) to 5 (very satisfied), and was best explained by a model that included hunting party success; hunter investment; temperature; and satisfaction with duck numbers, habitat conditions, hunting regulations, and crowding. While greatly reducing days available for hunting, access restrictions were associated with improved chances of hunting parties successfully harvesting ≥1 duck in 5 of 6 hunting seasons, and substantially greater numbers of ducks harvested by hunters in successful parties in 1 of 6 hunting seasons. Restrictions did not have a strong direct effect on hunting parties' satisfaction with a day's hunt. Uncontrolled factors, including weather and use of equipment by hunters, had important influences on hunter success, harvest, and satisfaction. Managers should carefully assess hunting activity, hunter expectations and desires, and hunting area characteristics when considering access restrictions on public hunting areas.     

Is there always an influence of shoal size on predator hunting success?

Theoretical and empirical studies predict that there should be a decrease in hunting success of predators with increasing prey group size. Most of these studies investigated situations in which predator and prey were in full view of each other before, during and after an attack. In this study, single rock bass Ambloplites rupestris were given an opportunity to launch surprise attacks at shoals of creek chub Semotilus atromaculatus that ranged in size from two to 13 fish. There was no significant influence of either shoal size or attack distance on predator success rate and no significant relationship between attack distance and shoal size. Furthermore, it was found that the leading fish of a shoal was attacked significantly more often than fish in other shoal positions, indicating that predation risk was not shared equally among shoal members. Also, leading fish in larger shoals (eight to 13 fish) were not more likely to survive a predator attack than ones in small shoals (two to seven fish).The consequences of these results are discussed in the general context of antipredator benefits of grouping.     

The effect of maternal age and experience on egg-size and hatching success in Wandering Albatrosses Diomedea exulans

The roles of maternal age and experience, on the one hand, and individual, year and random effects on the other, in influencing avian egg-size and hatching success have been much debated but seldom studied comprehensively. We investigated these topics with Wandering Albatrosses Diomedea exulans of known age (7–30 years) and experience (1–8 breeding attempts) over a 10-year period. Older and more experienced birds laid larger eggs. After allowing for year and controlling for experience, significant age effects remained; after controlling for age, no detectable experience effects remained. However, age accounted for only 6% of the overall egg-size variation. Egg-size varied significantly between years and has increased over the last decade. Individuals laid eggs of consistent sizes; 55% of the random variation in egg-weight was due to such effects. Egg- and hatchling-weight were very closely linked; larger eggs also had higher hatching success. The latter was influenced significantly by age and experience but neither remained significant after controlling for the other. Year effects were also detectable.
That there are significant effects of age, experience, year and individual on egg-weight (and hatching success) is probably typical of seabirds generally, though with different balances between factors depending on species and situation; however, insufficient data exist to examine this critically. Our finding that age was a more important influence than breeding experience does not support recent suggestions that hatching success is mainly influenced by experience and that experience will have a greater effect on reproductive success in long-lived species with high mate-fidelity. However, Wandering Albatrosses may have acquired much relevant experience before even starting to breed.     

Tracking the movement trajectory of newly emerged adult Chinese citrus flies with insect harmonic radar

Previous work reveals that the adult Chinese citrus fly, Bactrocera minax (Enderlein), emerges from the ground in citrus orchards and presumably disperses to alternate food sources in neighboring shrubs and trees, where it stays and becomes reproductively mature, and then later returns to the orchard to lay eggs. We investigated the trajectories of early emerged adult Chinese citrus flies, which were tracked with portable harmonic radar in 2013, 2014, 2015, and 2016 in four different habitats in Hubei province of China that presumably provided food sources for adults. This study we investigated whether early emerged adult Chinese citrus flies migrate into forests. A total of 47 adults were tracked following release in a citrus orchard. Our results showed that a total of 33 adults released in a citrus orchard flew into the forest, and 14 adults that disappeared during the tracking process in the citrus orchard. A total of 10 adults (in 2014) that were tracked and released in the forest flew to the forest. Of the adult flies investigated, 54.5% flew directly into the forest, while the remaining 45.5% finally arrived in the forest after repeatedly adjusting their trajectories. When there were Castanea mollissima Blume (Fagaceae) in the surrounding forest, the proportion of frequency of adult landing on the plant represented 58.3% and 88.5% of landing on all species in 2014 and in 2015, respectively. We conclude that early emerged adult Chinese citrus flies in the mosaic-type citrus orchard of the hilly terrain landform dispersed into adjacent forest.     

The effect of body temperature on the hunting response of the middle finger skin temperature

The relationship between body temperature and the hunting response (intermittent supply of warm blood to cold exposed extremities) was quantified for nine subjects by immersing one hand in 8°C water while their body was either warm, cool or comfortable. Core and skin temperatures were manipulated by exposing the subjects to different ambient temperatures (30, 22, or 15°C), by adjusting their clothing insulation (moderate, light, or none), and by drinking beverages at different temperatures (43, 37 and 0°C). The middle finger temperature (T _fi) response was recorded, together with ear canal (T _ear), rectal (T _re), and mean skin temperature (Tˉ _sk). The induced mean T _ear changes were −0.34 (0.08) and +0.29 (0.03)°C following consumption of the cold and hot beverage, respectively. Tˉ _sk ranged from 26.7 to 34.5°C during the tests. In the warm environment after a hot drink, the initial finger temperature (T _fi,base) was 35.3 (0.4)°C, the minimum finger temperature during immersion (T _fi,min) was 11.3 (0.5)°C, and 2.6 (0.4) hunting waves occurred in the 30-min immersion period. In the neutral condition (thermoneutral room and beverage) T _fi,base was 32.1 (1.0)°C, T _fi,min was 9.6 (0.3)°C, and 1.6 (0.2) waves occurred. In the cold environment after a cold drink, these values were 19.3 (0.9)°C, 8.7 (0.2)°C, and 0.8 (0.2) waves, respectively. A colder body induced a decrease in the magnitude and frequency of the hunting response. The total heat transferred from the hand to the water, as estimated by the area under the middle finger temperature curve, was also dependent upon the induced increase or decrease in T _ear and Tˉ _sk. We conclude that the characteristics of the hunting temperature response curve of the finger are in part determined by core temperature and Tˉ _sk. Both T _fi,min and the maximal finger temperature during immersion were higher when the core temperature was elevated; Tˉ _sk seemed to be an important determinant of the onset time of the cold-induced vasodilation response. Accepted: 29 April 1997     

Predicting fluctuations in the size of newly emerged sea-trout fry in a Lake District stream

The objective was to predict interannual fluctuations in the size of sea-trout fry when they emerged from the redd, using models developed from field data for 70 excavated redds (≥three per year), and from experimental data on egg and alevin development at 30 constant temperatures in the laboratory (range 1·5—10·5) C with 100 naturally fertilized eggs at each temperature). Egg weight increased with female length and also with the number of eggs laid in a redd, both relationships being well described by a power function. Early spawners were the largest females laying the largest and most numerous eggs, whilst late spawners were the smallest females laying the smallest and least numerous eggs, with middle spawners being intermediate between these two extremes. Mean values for egg weight and number of eggs per redd were obtained for these three groups. The numbers of early, middle and late spawners for each year of a 30-year study and the mean values from the excavated redds were used to estimate weighted means for the number of eggs per unit area and egg weight. Mean values varied considerably between years (30-year ranges: 518–7964 eggs per 60 m2; 112–138 mg wet weight). In the laboratory, mean weights of newly hatched alevins and newly emerged fry were both related positively to mean egg weights. Alevin and fry mean weights were independent of the number of days required for 50% of the eggs to hatch or fry to emerge. Models described in a previous paper formed the basis of those used to predict fry weights over the emergence period. Model predictions were validated by field data for the whole emergence period in 8 years (1967–1971, 1974, 1975, 1980), and by pre-fry weights on single dates in 21 years (1967–1987). As pre-fry densities on these single dates were very similar to egg densities for the same year class, mortality in the egg and alevin stages was very low. The chief objective was therefore fulfilled, and the extent of interannual fluctuations for the 30-year study showed some variation in mean fry weight (30-year ranges: 153–193 mg for both the whole emergence period and the date on which 50% of fry emerged) but a progressive decrease in fry weight through the emergence period. Possible reasons for this variation are discussed, and it is concluded that the size of the female spawners is the dominant factor.     

Energetics of breath-hold hunting: Modeling the effects of aging on foraging success in the Weddell seal

A simulation model was developed to predict age-related changes in foraging energetics of individual Weddell seals, Leptonychotes weddellii. Aging in diving animals is interesting because their characteristic cyclic sequence of apneustic hunting and eupnea should elevate oxidative stress, possibly accelerating aging. Such a hypothesis can be evaluated by modeling energetics of constrained, time-partitioned activities with well-defined costs. Three possible consequences of physiological aging in divers were specified and appraised. The model examined the potential impacts of age-related decline in muscle contractile ability, increased buoyancy, and reduced aerobic dive limit, alone and in combination, on a daily energy budget. A uniform age effect evident in model outputs is reduced foraging efficiency. The components of this net effect are exacerbated for sub-optimal behavioral-response settings or environmental conditions. The model predicts that with advancing age, efficiency declines increase for aging scenarios in the following order: simulated ‘young’ adults; ‘old’ seals with increased buoyancy; ‘old’ seals with reduced aerobic dive limit; ‘old’ seals having reduced muscle contractile efficiency; and, ‘old’ seals with all three conditions. The model indicates narrowed behavioral options to maintain positive energy balance in older animals, suggesting that behavioral plasticity may not allow older animals to compensate for age-related performance constraints.