Application of a marking-and-recapture method for the analysis of larval-adult populations of an insect,Nezara viridula (Hemiptera: Pentatomidae)

Difficulty arises in applying marking-and-recapture methods to insects when the probability of recapture of marked individuals is changed with advancing age, either due to detachment of the mark by moulting (in the case of larvae) or to changes in their survival rate or their behaviour. A modification of the re-recapture method (Leslie et al., 1953) has been devised to analyze the capture-recapture data of the 5th-instar larvae and adults of Nezara viridula L. Estimation of the rate of moulting to the adult stage is made with the aid of additional information on larval survival. Migration rates of the larvae between the two halves of the census field is estimated byIwao's (1963) method. Through these analyses, the dynamic feature of the population during transition from the 5th instar to, adult is revealed. Several problems involved in the application of marking-and-recapture methods to insect populations are discussed.     

A further note on Kiritani and Nakasuji's model for stage-frequency data including comments on the use of Tukey's jackknife technique for estimating variances

Some general equations for stage-frequency estimation are presented and their applications discussed.Tukey' s (1958) jackknife technique is suggested for the calculation of the approximate variances associated with estimators of population parameters.     

On the nature of errors involved in estimating stage-specific survival rates by Southwood's method for a population with overlapping stages

This paper has examined the effect of within-stage mortality on the estimation of stage-specific survival rates bySouthwood's (1978, p. 358) method. As pointed out bySouthwood , both the severity and timing of mortality affect the mean duration of a life stage, and consequently the estimate of the number of individuals entering that stage. Knowledge of the form of the survivorship curve permits correction of the estimate under certain circumstances. The use ofSouthwood's method with two overlapping stages having different rates and patterns of mortality leads to complex errors in the estimation of survival for the first stage. The nature of these errors is examined analytically and via a simulation model.Southwood's method is fairly robust, with moderate differences in mortality rates leading to acceptable errors in estimating survival for the first stage. When both the rate and pattern of mortality in both life stages are the same, then the survival estimate is made without error. Precise estimates of stage-specific survival will not usually be possible withSouthwood's method because of the errors introduced by the very parameters being measured. Direct measurement of mortality rates and survivorship patterns (seeSouthwood , 1978, p. 309) is strongly advised, at least in preliminary work.     

A further note on Kiritani and Nakasuji’s model for stage-frequency data including comments on the use of Tukey’s jackknife technique for estimating variances

Summary Some general equations for stage-frequency estimation are presented and their applications discussed.Tukey’s (1958) jackknife technique is suggested for the calculation of the approximate variances associated with estimators of population parameters.     

Population dynamics of the japanese clouded apolloParnassius glacialis butler (Lepidoptera: Papilionidae). I. changes in population size and related population parameters for three successive generations

1. Population dynamics of a univoltine butterfly Parnassius glacialis (Lepidoptera: Papilionidae) was studied with mark-recapture methods for three successive generations in a hilly region in Kanazawa City, Ishikawa Prefecture, Japan in 1981–1983.
2. Jolly (1965) andSeber's (1973) method was applied to the mark-recapture data to estimate population parameters (daily survival rate, longevity, population size, sex ratio, etc.).
3. Sampling ratios were at least 50% and 30% for males and females, respectively.
4. Mean daily survival rate for males ranged 0.81–0.86 and that for females 0.80–0.84. Mean longevity was about 4–7 days for the males and about 5 days for the females. Spiders killed more males than females. Maximum longevity for an individual recorded during the study was 31 days for males and 18 days for females.
5. Emergence of the butterflies was later and less synchronous in 1981 than in 1982 and 1983. This was thought to be due to later extinction of heavier snow in 1981 than in the other years.
6. The population remained relatively stable for the three successive generations, with estimated total numbers of 914, 1277, and 869.
7. Estimated sex ratio (% females) was 30–40% at emergence

     

On a method for estimating the rate of population interchange between two areas

A method for estimating the rate of population interchange between two areas is described in this paper. It is applicable to the case where the sampling ratios and the survival factors of the populations on two areas are different from each other. From the marking-and-recapture data taken at three successive occasions, we can obtain the estimates of emigration factors, total survival factors over two areas and the ratio of surviving migrants to the total survivors over the two areas, for each of two populations initially living on different areas.     

Estimating the survival rate and mean longevity for adults in a field population of the green rice leafhopper,Nephotettix cincticeps Uhler,by the application ofHokyo andKiritani’s method

Application of the female dissection method proposed byHokyo andKiritani (1967) was attempted in both 1968 and 1969 to estimate the daily survival rate and the mean longevity for the adult population of the green rice leafhopper, Nephotettix cincticeps, in a paddy field. The estimated mean longevity for females was far shorter than the physiological longevity of this species, ranging from 4 to 7 days with some variation between different generations. This could explain the remarkable discontinuity among successive generations which proved to form an important feature of the pattern of seasonal population changes of this insect. Between the two years, the estimated survival rate (and hence the mean longevity also) was negatively correlated to the estimated population size of adults that emerged in either of the two successive generations. This apparent density dependence suggests the possibility that the adult survival, including the effect of dispersal, plays some critical role in bringing about the remarkable population stability from year to year shown by the field population of N. cincticeps.     

A simulation study of three methods for estimating selective values and survival rates from recapture data

The methods ofManly (1973),Manly (1975) andManly (1977) for estimating survival rates and relative survival rates from recapture data have been compared by computer simulation. In the simulations batches of two types of animal were “released” at one point in “time” and recapture samples were taken at “daily” intervals from then on. The various methods of estimation were then used to estimate, the daily survival rates of type 1 and type 2 animals, and also the survival rate of the type 2 animals relative to the type 1 animals. Simulation experiments were designed to examine (a) the bias in estimates, (b) the relative precision of different methods of estimation, (c) the validity of confidence intervals for true parameter values, and (d) the effect on estimates of the failure of certain assumptions.     

A numerical solution of theVolterra equation for the growth of an animal population accompanying an autotoxic effect

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Contribution from the Department of Fisheries, Faculty of Agriculture, Kyoto University.     

A simulation study of population interaction between the greenhouse whitefly,Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae), and the parasitoidEncarsia formosa gahan (Hymenoptera: Aphelinidae) I. Description of the model

A simple simulation model was developed to simulate the population dynamics of the system of the greenhouse whitefly (Trialeurodes vaporariorumWestwood ) and the parasitoid Encarsia formosaGahan . On the assumption that temperature is constant, the whitefly population was described as theLeslie Matrix model. Parasitization and host feeding by the parasitoid population were modelled by means of a modified disc equation. The validity of the model was demonstrated by comparing the predictions of the model with the observed values obtained in greenhouse experiments.     

A method for the study of population size and survival rate of houseflies

A field population of houseflies, Musca domestica L., was studied by means of a mark-release-recapture method (Bailey's triple-catch method). The flies were marked with fluorescent dye powder, which lightened in laboratory experiments during the whole life time of the fly and did not affect the longevity of the flies. The flying, walking, and cleaning activity of the flies were not affected 2 days after marking. Population studies were carried out on a farm in North Sealand, Denmark, in September 1977–July 1978. The calculated population sizes ranged from 5 000–50 000. The mean duration of adult life of flies was found to be short, varying from 2.9–6.7 days, apparently independently of population size and of season.

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Eine Methode für das Studium der Populationsgrösse und der Uerberlebenstrate von Stubenfliegen

Zusammenfassung Eine Feldpopulation der Stubenfliege, Musca domestica L., wurde mit einer Markierung-Freilassung-Rückfangmethode untersucht. Die Fliegen wurden mit einem Fluoreszenzfarbpuder markiert, das in Laborversuchen während des ganzen Lebens der Fliegen bei Betrachtung in UV Licht sichtbar blieb und die Lebensdauer nicht beeinträchtigte. Die Flug-, Geh-und Putzaktivität der Fliegen war 2 Tage nach der Markierung unbeeinträchtigt. Die Populationsstudien wurden von September 1977–Juli 1978 auf einer Farm in Nord Seeland, Dänemark ausgeführt. Die errechnete Populationsgrösse schwankte zwischen 5 000 und 40 000. Die mittlere Lebensdauer der Fliegen war kurz und lag zwischen 2.9 und 6.7 Tage, offensichtlich unabhängig von der Populationsgrösse und der Jahreszeit.

     

A new method for estimating the adult survival rate of the Corncrake Crex crex and comparison with estimates from ring-recovery and ring-recapture data

The mean annual survival rate of adult Corncrakes Crex crex was estimated by three independent approaches: ring-recovery, ring-recapture and the shape of secondary remiges. The last method is new and uses measurements of the shape of the tips of the secondaries, which changes in the first post-juvenile wing moult to become less pointed. The estimates obtained by the three approaches were mutually compatible and indicated that annual survival is likely to be within the range 0.2–0.3. This low survival rate is likely to make the growth rate of Corncrake populations particularly sensitive to the effects of agricultural and conservation management on breeding success and recruitment. The survival rate of adult female Corncrakes was estimated for the first time (0.259) and was found not to differ significantly from an estimate for adult males (0.298) made in the same study area by the same method. It is concluded that the method based upon population counts and measurements of the shape of remiges has potential value for studies of the demography of Corncrakes and other species.     

Estimation of density,survival rate and dilution rate ofMecostethus magister (Orthoptera: Acrididae) populations by the mark and recapture method

Population Ecology -     

Degrees of heterogeneity and the survival of an insect population

Summary The results of simulation experiments with a stochastic model incorporating internal and external sources of heterogeneity suggest that the western tent caterpillar is a risk spreader of a type discussed byDen Boer (1968). By maintaining physiological plasticity in its population,M.c. pluviale can survive periods of bad weather and then expand rapidly in an improved climate. Intrinsic variability in the moths’ dispersal capacity also ensures that some will continue to contribute to populations in the climatic refuges where the species persists during unfavorable periods, while others can quickly colonize marginal areas as soon as favorable conditions return. This northern population of the western tent caterpillar seems distinctly less well adapted to a world in which the terrain and the weather are more homogeneous than on the Saanich Peninsula. As this series of papers is jointly produced by our whole group, the order of authorship on each is decided by chance, not protocol.     

Phenotypic plasticity in growth and fecundity induced by strong population fluctuations affects reproductive traits of female fish

Fish are known for their high phenotypic plasticity in life‐history traits in relation to environmental variability, and this is particularly pronounced among salmonids in the Northern Hemisphere. Resource limitation leads to trade‐offs in phenotypic plasticity between life‐history traits related to the reproduction, growth, and survival of individual fish, which have consequences for the age and size distributions of populations, as well as their dynamics and productivity. We studied the effect of plasticity in growth and fecundity of vendace females on their reproductive traits using a series of long‐term incubation experiments. The wild parental fish originated from four separate populations with markedly different densities, and hence naturally induced differences in their growth and fecundity. The energy allocation to somatic tissues and eggs prior to spawning served as a proxy for total resource availability to individual females, and its effects on offspring survival and growth were analyzed. Vendace females allocated a rather constant proportion of available energy to eggs (per body mass) despite different growth patterns depending on the total resources in the different lakes; investment into eggs thus dictated the share remaining for growth. The energy allocation to eggs per mass was higher in young than in old spawners and the egg size and the relative fecundity differed between them: Young females produced more and smaller eggs and larvae than old spawners. In contrast to earlier observations of salmonids, a shortage of maternal food resources did not increase offspring size and survival. Vendace females in sparse populations with ample resources and high growth produced larger eggs and larvae. Vendace accommodate strong population fluctuations by their high plasticity in growth and fecundity, which affect their offspring size and consequently their recruitment and productivity, and account for their persistence and resilience in the face of high fishing mortality.     

Robust design and the use of auxiliary variables in estimating population size for an open population

We consider the problem of estimating the population size for an open population where the data are collected over secondary periods within primary periods according to a robust design suggested by Pollock (1982, Journal of Wildlife Management 46, 757-760). A conditional likelihood is used to estimate the parameters associated with a generalized linear model in which the capture probability is assumed to have a logistic form depending on individual covariates. A Horvitz-Thompson-type estimator is used to estimate the population size for each primary period and the survival probabilities between primary periods. The asymptotic properties of the proposed estimators are investigated through simulation and are found to perform well. A data set for such a robust design of a small-mammal capture-recapture study conducted at Dummy Bottom within Browns Park National Wildlife Refuge is analyzed.     

A regression-based method for estimating mean treatment cost in the presence of right-censoring

In many clinical trials and evaluations using medical care administrative databases it is of interest to estimate not only the survival time of a given treatment modality but also the total associated cost. The most widely used estimator for data subject to censoring is the Kaplan-Meier (KM) or product-limit (PL) estimator. The optimality properties of this estimator applied to time-to-event data (consistency, etc.) under the assumptions of random censorship have been established. However, whenever the relationship between cost and survival time includes an error term to account for random differences among patients' costs, the dependency between cumulative treatment cost at the time of censoring and at the survival time results in KM giving biased estimates. A similar phenomenon has previously been noted in the context of estimating quality-adjusted survival time. We propose an estimator for mean cost which exploits the underlying relationship between total treatment cost and survival time. The proposed method utilizes either parametric or nonparametric regression to estimate this relationship and is consistent when this relationship is consistently estimated. We then present simulation results which illustrate the gain in finite-sample efficiency when compared with another recently proposed estimator. The methods are then applied to the estimation of mean cost for two studies where right-censoring was present. The first is the heart failure clinical trial Studies of Left Ventricular Dysfunction (SOLVD). The second is a Health Maintenance Organization (HMO) database study of the cost of ulcer treatment.