Endogenous timing mechanism controlling the circannual pupation rhythm of the varied carpet beetle Anthrenus verbasci

This paper describes the detailed characteristics of the circannual pupation rhythm in Anthrenus verbasci determined by laboratory experiments under various photoperiods and temperatures. The frequency distribution of larval duration showed a periodic pattern over 2-3 years and the period was 37-40 weeks under a constant short-day photoperiod (light:dark 12:12) at 20 degrees C. This rhythm showed temperature compensation to some extent under a short-day photoperiod between 17.5 degrees C and 27.5 degrees C. Under alternations of a long-day (light:dark 16:8) and a short-day photoperiod, pupation occurred 21-24.5 weeks after transfer from a long-day to a short-day photoperiod. Therefore, we concluded that the timing of pupation in A. verbasci is controlled by a circannual rhythm and its zeitgeber is a change in photoperiod. Furthermore, when larvae were transferred from a long-day to a short-day photoperiod at various ages, the larval duration after the photoperiodic transfer depended on the time of the transfer. This difference can be explained by phase-dependent phase shifts in the circannual rhythm.     

Circannual pupation rhythm in the varied carpet beetle Anthrenus verbasci under different nutrient conditions

Anthrenus verbasci pupates in spring and the timing of pupation is controlled by a circannual rhythm. Although A. verbasci is considered to be a univoltine species in Japan, it is assumed that larval development in its natural habitats, including bird nests, varies with nutrient availability, and that the life cycle often takes two or more years to complete. In the present study, larval development and pupation times were compared under constant and outdoor conditions in larvae provided a diet of either high‐nutrient bonito powder or low‐nutrient pigeon feathers. Although a circannual pupation rhythm was observed irrespective of the diet used, larval development was slower on feathers than on bonito powder. The pupation times on feathers varied over three years or more under both constant and outdoor conditions. Under outdoor conditions, larvae grown on feathers needed three years to approach the weight gained within a year by larvae grown on bonito powder. It is considered that life cycle length in A. verbasci is often two years or more in nutritionally unstable natural habitats, and that this species has probably evolved a circannual rhythm as a seasonal adaptation to nutrient‐poor environments.     

Intra- and interspecies variations in pupation height in Drosophila.

In order to study the pupation site preference which is an important component of larval behaviour, pupation height was scored in Drosophila ananassae, D. bipectinata and D. malerkotliana by using a large number of strains of these species. The mean pupation height of different strains ranged from 1.1 to 8.7 mm in D. ananassae, from 0.41 to 0.75 mm in D. bipectinata and from 1.0 to 1.3 mm in D. malerkotliana. The analysis of variance and t-test were performed to test intre- and interspecies variations in pupation height. These tests revealed significant variation among three species. Significant variations among different strains of the same species were also found in D. ananassae and D. bipectinata. These observations provide evidence for intra- and interspecies variations in pupation height in Drosophila. Variations among different strains of the same species in pupation height are attributable to genetic heterogeneity among the strains.     

Drosophila salivary gland proteins and pupation

Pulse-labeling experiments of salivary glands from the prepupal stages of development showed selectively high rates of synthesis of a set of low molecular weight proteins (6K–12K). These proteins are stably maintained in the salivary glands during prepupal development and are subsequently transported to the pupation fluid (found between the pupal case and the prepupal cuticle) when pupation occurs. These small polypeptides are very basic with the major components having isoelectric points of 8.6–8.7 and the minor components having isoelectric points of 9.1–9.5. This study shows the continuing function of the salivary glands—specifically, the synthesis and secretion of a set of proteins with a putative role in pupation.     

Gallop rhythm.

Seventy-five percent of family practitioners in Ventura County, California, responded to a seven-page mailed questionnaire. One third of the practitioners do no obstetrics. The physicians counsel seven patients to every delivery performed and to every surgical procedure performed. Family practice consists of medicine and pediatrics, rather than surgery, obstetrics and psychiatry. Family practitioners use referrals to community health care services in a limited fashion. Lack of information about availability of community resources may be the reason.     

Selection for pupation height in Drosophila melanogaster

Divergent directional selection for high and low pupation height was practiced in D. melanogaster. A quick response was observed in the two directions of selection. This is the first time selection for low pupation sites was successful. Realized heritabilities were 18% and 13% for the high and low lines. Reciprocal crosses between divergent lines showed little or no dominance for low pupation sites. The need for a strict control of environmental factors when measuring pupation height is emphasized.     

Protein synthesis rhythm.

The three-dimensional structure of a protein molecule appears to depend on the amino acid sequence of the protein in an as yet incompletely described manner. If the amino acid sequence is replaced by a numerical sequence of values representing a physical or chemical property of amino acids, the resulting numerical sequence is amenable to autocorrelation analysis. Further, if certain geometrical parameters are calculated from the three-dimensional structure of a protein to form a configurational series, pairs of property series and configurational series can be analyzed by cross-correlation techniques. The data base for the analysis was the three-dimensional structures of ten proteins as determined by X-ray crystallography. Such analysis yields the result that the hydrophobicity of an amino acid residue in a protein influences the orientation angle of the amino acid side chain. This result is consistent with the widely current “oil-drop” model of protein structure. Hydrophobicity also appears to influence the backbone dihedral angle φ, but not ψ Such a directional effect cannot be explained by a current model of information transfer in protein helices. The magnitude of the cross correlations does not appear to be satisfactory for construction of a transfer function model for the prediction of general features of protein structure from amino acid sequences.     

Genetic control ofHylemya antiqua III. Differences in pupation ability between two strains

Some relevant traits of a wild (L) and a laboratory (C) strain of Hylemya antiqua (Meigen ), determining differences in their pupation ability under experimental conditions have been investigated in relation to genetic control. The wild strain showed an intrinsic higher pupation ability than the laboratory strain. The minimum feeding period was 0.6 days longer for the C strain. The minimum larval dry weight was different for the two strains. With a normal feeding period C larvae pupated on average 1.63 days later than L larvae. By the shortening of the larval feeding period an acceleration of the larval development of both strains was observed: the acceleration of development was more marked for the wild strain. This result has been contrasted with published works on Drosphila. The consequences of these differences as far as the competitive ability of each strain is concerned, have been discussed in relation to genetic control.     

稻纵卷叶螟卷叶有虫率与化蛹率关系的研究

探索利用稻纵卷叶螟 Cnaphalocrocis medinalis（Guenée）卷叶有虫率估测化蛹率的方法和途径。本文基于稻纵卷叶螟化蛹进度的田间调查数据,用化蛹率（y）和卷叶有虫率（x）分别拟合直线函数、一元二次函数、一元三次函数、对数函数、指数函数和幂函数6种不同模型。结果表明,以一元三次函数方法估计精度最高,误差最小,应用效果最好,并根据最优数学模型建立化蛹率（y）与卷叶有虫率（x）的关系速查表。生产中可以应用拟合的 最优数学模型对田间稻纵卷叶螟化蛹进度进行监测。     

Studies on the circadian rhythm of phosphoenolpyruvate carboxykinase. III. Circadian rhythm in the kidney.

Phosphoenolypyruvate carboxykinase [EC 4.1.1.21] activity in rat kidney shows a circadian rhythm with the highest activity between 0200 h and 0800 h and the lowest activity between 1400 h and 2000 h. The rhythm was observed in both sexes and throughout the year. Actinomycin D and cycloheximide effectively blocked the circadian increase in enzyme activity. These findings suggest that the circadian increase in phosphoenolypyruvate carboxykinase activity is due to net synthesis of enzyme protein through newly synthesized mRNA. In experiments with kidney cortex slices, gluconeogenesis from the radioactive precursor, [14C]malic acid, was considerably higher at 0200 h than at 1400 h, varying in parallel with the change in the enzyme activity.     

Implications of Chaoborus pupation and ecdysis in cold water

1. Cold water acted differently to delay and lengthen the pupation period for the larvae of two species of the zooplankton predator Chaoborus (Diptera: Chaoboridae). During Chaoborus pupation, the zooplankton community is released from predation, while the dark-coloured Chaoborus pupae are more susceptible to their own predators.
2. Fourth instar larvae of Chaoborus americanus and C. trivittatus , collected from an oligotrophic lake, were reared individually at 5 °C in the dark. Chaoborus americanus was also reared at 9 and 12 °C under spring photoperiod conditions (L : D, 16 : 8 h). Individuals were observed through pupation to emergence (ecdysis) or death.
3.  Chaoborus americanus pupated at 5, 9 and 12 °C with substantial emergence only at 12 °C. In comparison, C. trivittatus emerged at 5 °C. Light was not a necessary cue for pupation and ecdysis, contrary to previous reports. Cold water delayed the onset and lengthened and increased the variability of the duration of pupation.
4. In Shirley Lake, C. americanus pupated in late June–early July while C. trivittatus pupated first in April and again in June–July.
5.  Chaoborus americanus pupae needed a temperature cue to complete ecdysis. The ecdysis temperature threshold helps to explain the difference in pupation timing, and the geographical distribution, of C. americanus and its relatively inflexible life history contrasted with C. trivittatus . Delayed predator pupation in years with low spring temperature can affect the community dynamics of the prey.     

Asynchronous pupation of univoltine insects as evolutionarily stable phenology

Evolutionarily stable seasonal timing of larval feeding stages is studied theoretically for univoltine insects. In the evolutionarily stable (or ESS) population, each individual maximizes its own lifetime reproductive success by choosing the hatching and pupation dates, given the resource availability curve with a peak in the middle of a year, a higher daily mortality in the feeding stages, and the growth rate decreasing with the larval biomass in the population. If growth rate is proportional to the body size, the population at the ESS is composed of a mixture of phenotypes differing in hatching and pupation, but pupation interval over which some popation occur every day is much longer than hatching interval. If growth rate increases with the body size at a speed slower than linearly, large sized larvae should pupate earlier than small ones.