FIELD STUDIES ON THE INFLUENCE OF WEATHER ON EGG-LAYING BY THE CABBAGE ROOT FLY, ERIOISCHIA BRASSICAE BCHÉ. II

Observations on the intensity and duration of egg-laying by Erioischia brassicae Bché were continued in 1953 on the same site as in 1952. Eggs were first observed on 31 April and the spring peak period of egg-laying lasted from 3 to 30 May with a daily average of 40 eggs/plant. The mean total in spring 1953 was 1287 eggs/plant. Summer peaks occurred on 1–20 July (average 17 eggs/day/plant) and 5–11 August (average 21 eggs/day/plant).
In the field the threshold of reproduction was approximately 60° F. The rate of egg-laying was highest at 65–70° F. and it declined during prolonged periods of higher temperatures.
The annual cycle of generations, as shown by egg counts and confirmed by the examination of puparia, consisted of two generations and a partial third. The spring generation developed without a prolonged diapause, and there was complete emergence during the summer. The overwintering puparia came from the second and third generations of larvae.     

THE SYSTEMIC INSECTICIDAL ACTION OF SODIUM FLUOROACETATE AND OF THREE PHOSPHORUS COMPOUNDS ON THE EGGS AND LARVAE OF PIERIS BRASSICAE L.

Four compounds, bis dimethylaminophosphonous anhydride ( anhydride ), bis (dimethylamino)fluorophosphine oxide ( oxide ), diethyl paranitrophenyl phosphate ( E 600) and sodium fluoroacetate ( acetate ), previously shown to have systemic insecticidal activity against aphids, have now been tested against the eggs and larvae of Pieris brassicae L.
The anhydride proved to have very little toxic action on Pieris , but the other three compounds showed both contact toxicity and systemic insecticidal action when taken up by the roots of cabbage plants from solution and from soil. The acetate, but more especially the E600, also showed systemic action following application to the leaves.
In all cases the order of decreasing toxicity was E600 > acetate > oxide > anhydride. E600 is the only compound which is outstandingly toxic to Pieris eggs and larvae. It has the added interest that when watered on to the roots of cabbage plants it kills larvae in egg batches on the leaves. Death takes place at the stage when the larvae are biting through the shells. The oxide and acetate proved to be surprisingly innocuous.
Unless it is felt to be too poisonous E600 is worthy of consideration as an insecticide against Pieris eggs and larvae, since it is highly effective as a contact insecticide and also has some systemic action.     

BREAKING THE REST PERIOD IN BLACK CURRANTS WITH GIBBERELLIC ACID AND LOW TEMPERATURE

A single application of gibberellic acid (GA) was successful in breaking the rest period of black currants in September, October and November, while chilling for 2 weeks was insufficient to be effective.
The highest percentage of bud burst was obtained by GA application immediately after defoliation. Delay in GA application after defoliation decreased and delayed plant response because penetration of GA was hindered. Multiple and very early GA applications immediately after taking the plants into the glasshouse caused shedding of undeveloped buds.     

山西省代县小鸊鷉繁殖生物学的研究

１９８５—１９９４年的３—１１月,在山西省代县对小鸊鷉的繁殖生物学进行了研究。该鸟在山西省为夏候鸟,每年最早３月６日迁来,最晚１１月２４日迁离,居留期为２５５天左右。种群密度在繁殖前的４月为１．３７,繁殖后的９月为１．９５（只／ｈａ）。产卵始期为５月２７日,日产１枚,窝卵数５—８枚,产出第二枚卵时开始孵卵。观察到最早孵卵期为５月２８日,孵卵期２０－２２ｄ。雏鸟出壳先后顺序与产卵先后顺序相一致,孵化率为９５．４５％,雏鸟为早成鸟。     

THE BIOLOGY AND CONTROL OF OTIORRHYNCHUS CLAVIPES BONSD. (RHYN. COLEOP.), A PEST OF STRAWBERRIES

Otiorrkynchus clavipes Bonsd. is a serious pest of strawberries around Cheddar, Somerset. The weevils nibble the foliage, the larvae eat the roots of the plants, and burrow into the rootstock.
The beetles appear in two waves, pupating in the autumn and emerging en masse in the spring, or pupating in the late spring and summer and emerging in succession between mid-June and the end of August. Both sexes are found and can be distinguished by the posterior thoracic sterna, which are concave in males and convex in females. Mating is alternated with egg-laying and the beetles lay between 100 and 300 eggs per female. On emergence the beetles eat voraciously, and roughly one egg is laid for every 10 sq.mm. of leaf consumed. Both parthenogenetic and fertile eggs are laid and hatch in between 17 and 24 days.
The larvae burrow rapidly when hatched and can only penetrate soil spaces which will admit their head capsules. The distribution of head capsule widths in mixed populations of larvae of all ages shows there are five instars. While feeding, the larvae are clustered within the root range of the plants and find their way to their food from plant to plant, guided by the exudates from the strawberry roots. As the larvae grow older they descend in the soil and turn to white soft pupae in smooth earthen cells 6–8 in. below the plants.
Adult damage to foliage is unimportant but larval damage to roots is serious and has been largely responsible for restricting the effective life of the strawberry beds to at most 2 years. Although weevil attack can be avoided by growing the crop in a 1-year rotation, control is difficult owing to the intensive cropping, which creates the most suitable conditions for the spread of the infestations. The adults are killed with 10% DDT dust; and the larvae by DDT and BHC preparations poured on to the soil, at a pint per plant, or by DD injection. The limitations and possibilities of various methods of control are discussed.     

The influence of plant age on resistance of radish to cabbage root fly egg-laying

Cabbage root fly ( Delia brassicae ) egg-laying around radish plants ranging in age from newly emerged seedlings to plants with flowering shoots was studied in the field and laboratory. The attractiveness of radish changed with age, one peak in egg-laying occurring just before plants were of marketable size and further peaks as they produced flowering shoots. The pattern of egg-laying was similar for the six radish cultivars tested, both in the field and laboratory, irrespective of whether flies did or did not have a choice of plants of different ages. At any one age, there was no correlation between egg-laying and plant size. Selection within radish cultivars for the extremes of the range of egg-laying preference appeared to alter the cycle of attractiveness of different radish stocks to cabbage root fly, the response being influenced by environmental conditions.     

The effect of plant density on populations of the cabbage root fly on four cruciferous crops

To study the effects of plant density on populations of the cabbage root fly (Erioischia brassicae), cabbage, cauliflower, Brussels sprout and swede were each planted in plots with twenty-four concentric circles of plants at spacings ranging from 10 to 90 cm between the individual plants. Plants treated with a root drench of chlorfenvinphos and untreated plants were each sampled at ten plant densities which ranged from 1–5 to 68-3 plants/m². In the absence of insecticide, the numbers of overwintering cabbage root fly pupae produced ranged from c. four per m² at the lowest plant density to 200 per m² at the highest. The number of pupae per m² was proportional to plant density to the powers 0–98,0-77,0–69 and o-6i for the swede, cauliflower, cabbage and Brussels sprout crops, respectively. The magnitude of each cabbage root fly population was determined mainly by plant density but also by the cultivar used as host plant. The results suggested that, in a given locality, when changing from low to high plant density crops during a growing season it should be unnecessary to apply insecticide to control cabbage root fly; conversely, a change from high to low plant densities would necessitate an extremely efficient application of insecticide.     

The timing of breeding and wing-moult of four African Sturnidae

Wing-moult of the Cape Glossy Starling, Red-winged Starling, Pale-winged Starling and Pied Starling was examined primarily from specimens in southern African museums. Breeding data were obtained from nest record cards.
The Cape Glossy Starling breeds from October to March, with the moult period from December to May. There is no evidence of moult-breeding overlap in individual birds. The Red-winged Starling breeds from September to March, while the moult takes place between November and April, overlapping with the second broods. The Pale-winged Starling breeds from October to April and moults between November and May. The Pied Starling moults between November and April, while breeding varies regionally, occurring concurrently with moulting in some areas.     

STUDIES OF THE DIEDERIK CUCKOO CHRYSOCOCCYX CAPRIUS IN THE TRANSVAAL

The migrant Diederik Cuckoo Chrysococcyx caprius was studied on a 72–acre area near the Klein Jukskei River near Johannesburg from 1955–1958. The birds first arrive in early October, after which the males take up territories and call continually until February; subsequent calls up to April are probably made by young birds.
Courtship displays, which involve courtship feeding, and egg-laying follow the birds' arrival by about a month. The Red Bishop Euplectes orix was the species most commonly parasitized, with smaller equal numbers of Cape Sparrows Passer melanurus and Masked Weavers Ploceus velatus . The cuckoos' eggs differ according to the host species and in two cases hatched between ten and 14 days after laying. The chicks normally evict their hosts' offspring on the second or third day after hatching. The fledging period appears to be roughly 19–20 days, and there is a period of post-fledging care lasting between 17 and 38 days, during which the chicks are fed different foods by different host species (grass seeds by bishops; insects of different sizes by weavers and sparrows).
The fact that the eggs and the calls of the chicks vary according to their host species suggest the existence of three separate host-specific strains in this area. The incidence of brood parasitism in Red Bishops' nests varied from 7–50% and averaged 25%.     

鼎突多刺蚁群体结构和生活史的研究

本文报告了鼎突多刺蚁(Polyrhachis vicina Roger)的群体结构和生活史。通过研究表明,鼎突多刺蚁一年发生一代,以蚁后、雄蚁、工蚁、幼虫和卵越冬。卵和幼虫在冬天发育停滞(或极慢)。到了春天,随着气温的上升,卵和幼虫又恢复正常发育。据室内人工饲养观察,卵的发育历期为23.8±2.5天(平均温度26℃)幼虫为20.4±4.4天(26℃),工蚁蛹为19.8±5.5天(27℃)。成长工蚁在5—11月出现;8—11月,雄蚁从蛹中羽化;10月,雌蚁从蛹中羽化。雌蚁分飞交尾后,进入邻近蚁巢或回到原巢,脱翅成为蚁后。蚁巢内存在着多后现象。     

Life-history variation in selfing multilocus genotypes of the land slug Deroceras laeve (Pulmonata: Agriolimacidae)

The land slug Deroceras laeve shows an enormous variation inlife-history traits. Here, we compared several life-historycharacters (i.e. length of the prereproductive period, growthduring the egg-laying period, number of eggs, hatching success)within and among five selfing homozygous multilocus genotypes(MLG) and investigated a possible trade-off between the numberof eggs produced during the egg-laying period and growth duringthe egg-laying period. Life-history traits were highly variable.There was no significant correlation between slug size and fecundity.Slugs that matured early produced more eggs than slugs thatmatured later. Life-history traits were significantly differentamong MLGs, suggesting that genetic factors may affect and explainat least part of the variation in life-history traits in D.laeve. Finally, we found no evidence of a trade-off betweenthe number of eggs produced during the egg-laying period andgrowth during the egg-laying period. (Received 1 June 2005; accepted 28 October 2005)     

THE ANNUAL RE-OCCUPATION OF BREEDING SITES BY THE FULMAR

The Fulmar has a long period at the breeding colony prior to egg-laying. The pattern of annual occupation and build-up in numbers has been examined in detail at Marsden, Co. Durham, at a colony in which over 100 eggs are laid annually (Order 3 of Fisher's classification). The re-occupation of the cliff starts in early November with an occasional visit by one or two birds. The main period of activity at the cliff is during the morning and, as the numbers build up, the diurnal period of occupation increases. By mid-December the first birds to arrive in the colony do so before dawn and the last to leave remain well after dark until near midnight. Almost throughout the pre-egg stage, the colony is deserted each night and re-occupied the next day and birds only stay regularly overnight just before egg-laying. A similar pattern of occupation occurs after breeding but in the reverse order. The numbers of birds at the colony in January and February exceed the breeding population and include many non-breeders. The non-breeders progressively decline in numbers until May when only the breeding birds remain with a few non-breeding birds. The daily variation in the numbers of birds at the cliff is influenced by the wind speed. In general, the birds leave the colony under freshening conditions and the number present at the colony can be interpreted in terms of the wind conditions over the last three days. It is suggested that the synchronised departures are primarily feeding trips, the birds using the strong winds to reach feeding areas, except that the departure just before egg-laying is linked to egg development and synchronised laying in the colony. Competition between Fulmars and Kittiwakes for nesting sites usually results in the Kittiwakes gaining the site. This is achieved by the Kittiwakes taking over the Fulmar sites during one of the latter's departures.     

CLUTCH CHARACTERISTICS AND EGG DISCRIMINATIVE ABILITY OF THE AFRICAN VILLAGE WEAVERBIRD PLOCEUS CUCULLATUS

Over a three-year period, 917 eggs from 27 females were collected from a captive colony of African Village Weaverbirds Ploceus c. cucullatus. A study was made of egg-laying and incubation behaviour, clutch characteristics and egg recognition.
Fifteen yearling females laid their first clutches at a mean age of 348 days after hatching. The mean clutch-size was 2.26 in adults and 1.68 in yearlings. The mean clutch replacement interval was 6.6 days in adults and 7.4 days in yearlings with an absolute minimum of 4 days. Eggs were laid at intervals of from 24 to 26 hours beginning usually 2–3 hours after dawn.
The eggs laid by this species vary in ground colour and pattern of spotting between different females, but egg pigmentation is constant for each individual bird. The results of 322 egg-replacement tests showed that an individual female could recognise her own egg type and would eject from the nest eggs differing markedly from her own. The incidence of rejection was proportional the degree of difference between the eggs. The possible implications for parasitism by the Didric Cuckoo Chrysococcyx cuprius are discussed.     

杭州郊区菜蚜种群的数量消长规律

对杭州郊区菜蚜的数量消长规律进行了连续多年的系统调查 .结果表明 ,在杭州郊区十字花科蔬菜上发生的菜蚜只有桃蚜 (Myzuspersicae)和萝卜蚜 (Lipaphiserysimi) .2种菜蚜混生种群的数量消长 1年中有 2个明显的高峰 ,分别出现在 5～ 6月和 1 1月前后 ;一般年份高峰期田间虫量可达平均每株 50 0头以上 ,且第 2个高峰虫量较高 ,持续时间较长 .在夏末秋初气温明显偏低的年份 ,8～ 9月作物上虫量上升迅速 ,最高也可达平均每株上千头的水平 .盛夏和隆冬季节数量都很低 .每年的 1 2月至次年的 5月以桃蚜占绝对优势 ,7～ 1 0月以萝卜蚜占绝对优势 ,而 5～ 7月和 1 0～ 1 2月则 2种蚜虫的发生比例交错变换 .温度是决定菜蚜混生种群数量消长规律和导致 2种蚜虫季节消长规律差异的一个主要因子 .文中对食料、天敌等因子的作用也做了讨论 .     

Fecundity and mortality in populations of Salicornia europaea agg. at Skallingen, Denmark

Seedlings of the annual, Salicornia europaea (sensu stricto), germinated in the outer marsh sand flats at Skallingen in early May, and the relative growth rates of root and shoot were high during the establishment phase. Mortality of plants, which was not density-dependent, was greater than 70% in most plots from early May to early October, as a result of wave action, desiccation and the presence of algal mats.
Salicornia ramosissima was present in the outer and inner marshes mixed with Puccinellia maritima . Seedling densities of this annual were high, and in early May growth rates were lower than those for Salicornia europaea . Overall mortality of plants from early May to early October was density-independent. Mortality of S. ramosissima in the inner marsh was only 50% from May to October, whereas the mortality of S. ramosissima in the outer marsh was 95% in the same period.
Different levels of seed production per plant, which reflected differences in plant architecture, were evident between the two micro-species.
Reciprocal transplants from the inner marsh failed to survive on the outer marsh sand-flat. Mean seed production per plant in plants transplanted from the outer marsh sand-flat to the inner marsh was only 10% of the value of the control populations. The distances of seed dispersal were different in the outer and inner marsh. Low recruitment occurred in areas cleared of Salicornia plants in the inner marsh, unlike the situation in the outer marsh sand-flat where tides dispersed seed.     

External radiation exposure of residents living close to the Mayak facility: main sources,dose estimates,and comparison with earlier assessments

In 1951 and 1952 specialists from the Mayak production association investigated the radiological situation in the area of the Metlinski reservoir that was located 5-7 km from the site of liquid radioactive waste (LRW) discharge. Based on their measurements of both the specific radioactivity in the water and the dose-rate above the water surface, the gamma-field above the water surface in 1951 was demonstrated to be mainly due to (95)Zr+(95)Nb. The dose-rate at the shore of the reservoir was calculated for the period 1949-1951. In November and December 1951, the gamma-field at the shore was mainly due to (140)Ba+(140)La. For the period 1949-1951, the external exposure of the Metlino population due to the decay of these radionuclides was about 200 R (2 Sv), most of the dose having been produced in 1951. The contribution of (137)Cs to external doses did at that time probably not exceed a fraction of several percent. This finding is in contradiction to the assumptions made in the most recent TRDS-2000 system that was developed to reconstruct the doses to the residents of the Techa river. The results presented here demonstrate that the reconstruction of external doses received by the Metlino population as well as by the Techa river residents can be improved for the most critical period between 1949 and 1954.     

Influence of target plant density on herbivorous insect oviposition choice: Ambrosia artemisiifolia L. (Asteraceae) and Zygogramma suturalis F. (Coleoptera: Chrysomelidae)

Zygogramma suturalis F. has been introduced to Russia for the biological control of the common ragweed Ambrosia artemisiifolia L. The functional response of Z. suturalis to the density of the target plant was studied at two levels: between plants and between 0.1 m² sampling plots. The number of Z. suturalis eggs per unit of plant weight was almost independent of plant weight, indicating that a functional response between plants is absent. However, tall and intermediate height plants received more eggs per phytomass unit than short plants. Between plots, correlation analysis showed that absolute Z. suturalis egg density is positively dependent on the ragweed density. Experiments showed that the locomotor activity of ovipositing females decreased when on the ragweed, suggesting orthokinesis. The number of leaf beetle eggs per unit of ragweed weight was negatively correlated with host plant density in May‐June, when the majority of eggs are laid, but was positively correlated in July and loosely, or not significantly, correlated in August. Seasonal changes in the functional response of a herbivorous insect to host plant population density have not been reported previously. A negative functional response of a herbivorous insect to target plant density can be a serious obstacle to the biological control of weeds.     

Effects of the Host Species and the Number of Parasitoids per Host on the Size of Some Trichogramma Species (Hymenoptera: Trichogrammatidae)

The size of some Trichogramma spp. adults and especially the ovipositor length depends on the species, but is also related to the host species and to the number of parasitoids per host. The length is greater in T. evanescens than in T. pretiosum itself greater than in T. exiguum, but the width is similar in the three species. For T. evanescens, the size obtained in Mamestra brassicae host when three or four insects emerged is similar to that obtained in Ephestia kuehniella host when singly parasitized. The size of the ovipositor is important because it may influence the possibility of in vitro egg laying in artificial host eggs. A shorter or a narrower ovipositor could cause difficulties in egg-laying into artificial host eggs composed of a membrane of unsuitable thickness.     

Seasonal and vertical patterns of egg-laying by the freshwater fish louse Argulus foliaceus (Crustacea: Branchiura)

Argulus foliaceus is a damaging fish ectoparasite for which new control measures are being developed based on egg-removal. In an attempt to develop further understanding of seasonal and vertical egg-laying patterns in this parasite, egg-laying activity was monitored over the period 14 April to 17 November 2003 in 2 rainbow trout Oncorhynchus mykiss fisheries in Northern Ireland, UK. At Site 1, egg-laying was continuous from 21 April to 17 November, when water temperature was above 8 to 10 degrees C. At Site 2, egg-laying was continuous from 4 June to 29 October. In the early months of the season, egg-laying was recorded mainly within the top 1 m of the water column; however, a significant shift to deep water egg-laying was recorded between 7 July and 17 November at Site 1 and between 20 August and 29 October at Site 2. Egg clutches were preferentially laid at depths of up to 8.5 m during this time (Site 2), a feature of egg-laying hitherto unappreciated. Temperature and dissolved oxygen did not differ significantly among depths, but there was an increase in water clarity over time. However, the precise environmental triggers for deep water egg-laying are still unclear. These new insights into the reproductive behaviour of this species will be useful in developing control methods based on egg-removal.     

THE INFLUENCE OF STORED POLLEN AND OF COLONY SIZE ON THE BROOD REARING OF HONEYBEES

Four hundred and thirty records of the numbers of bees in honeybee colonies and of the amounts of brood and pollen present have been kept during various months of the years 1945-53, and the data have been used to calculate total and partial regression coefficients showing the influence of stored pollen and of colony size on brood rearing throughout the year.
It was found that pollen storage and colony size were correlated but that, even allowing for this, colony size and pollen both independently influenced brood rearing.
The annual distribution of the total regression coefficients of brood on pollen was somewhat similar to the brood curve itself, rising from a minimum in October and November to a maximum in midsummer, while the partial regression coefficients showed less clearly marked but similar features.
Both total and partial regression coefficients showing the influence of colony size on the amount of brood reared were also at a minimum in October and November, but reached their peaks in May.
The quantities of brood present in these colonies at Aberdeen, Scotland, followed a pattern similar to that given by Nolan for colonies near Washington, D.C.