Ecological aspects of cattle tick control in central Zambia

In ecological studies in central Zambia, both climate and ecotype affected population dynamics of tick species. Below average rainfall for several years caused a suppression in numbers of Rhipicephalus appendiculatus Neumann adults. Reduction in rainfall leading to changes in grazing patterns is thought to have been responsible for an increase in numbers of Amblyomma variegatum Fabricius adults in a grassland habitat. There were reasonable correlations between numbers of each tick species on individual hosts over 1 year old. However, there were no relationships between numbers of ticks and bovine lymphocyte antigens (BoLA).     

Seasonal variation in numbers of eggs laid byCulex quinquefasciatus Say (Diptera: Culicidae) at Khartoum

Regular counts of the eggs ofCulex quinquefasciatus Say were recorded during the period April 1979 – March 1981. The results indicate that the lowest numbers of eggs laid were during summer months (May and June) and the highest ones were during winter months (November and January). The decline of numbers during summer was mainly due to small size of adults (0.57 mg, average wt of female). Populations flourished during the rainy season (July – October) and reached their peak in August. Bigger batches of eggs were then obtained. In winter prolongation of larval life gave rise to large-sized adults and hence bigger batches of eggs.     

Hippocampal neurogenesis is associated with migratory behaviour in adult but not juvenile sparrows (Zonotrichia leucophrys ssp.)

It has been hypothesized that individuals who have higher demands for spatially based behaviours should show increases in hippocampal attributes. Some avian species have been shown to use a spatially based representation of their environment during migration. Further, differences in hippocampal attributes have been shown between migratory and non-migratory subspecies as well as between individuals with and without migratory experience (juveniles versus adults). We tested whether migratory behaviour might also be associated with increased hippocampal neurogenesis, and whether potential differences track previously reported differences in hippocampal attributes between a migratory (Zonotrichia leucophrys gambelii) and non-migratory subspecies (Z. l. nuttalli) of white-crowned sparrows. We found that non-migratory adults had relatively fewer numbers of immature hippocampal neurons than adult migratory birds, while adult non-migrants had a lower density of new hippocampal neurons than adult and juvenile migratory birds and juvenile non-migratory birds. Our results suggest that neurogenesis decreases with age, as juveniles, regardless of migratory status, exhibit similar and higher levels of neurogenesis than non-migratory adults. However, our results also suggest that adult migrants may either seasonally increase or maintain neurogenesis levels comparable to those found in juveniles. Our results thus suggest that migratory behaviour in adults is associated with maintained or increased neurogenesis and the differential production of new neurons may be the mechanism underpinning changes in the hippocampal architecture between adult migratory and non-migratory birds.     

Control of Myzus persicae and Lipaphis erysimi (Hemiptera: Aphididae) by adults and larvae of a flightless strain of Harmonia axyridis (Coleoptera: Coccinellidae) on non-heading Brassica cultivars in the greenhouse

The green peach aphid [Myzus persicae (Sulzer)] and turnip aphid [Lipaphis erysimi (Kaltenbach)] are economically important pests with a worldwide distribution. We have evaluated the efficacy of releasing adults and larvae of a flightless strain of the multicolored Asian lady beetle (Harmonia axyridis Pallas) as a control measure against these aphids on plants of non-heading Brassica cultivars. Both adults and larvae of H. axyridis were observed to be effective biocontrol agents, markedly decreasing the numbers of aphids. The residence duration of adults was longer than that of larvae. The proportion of non-marketable plants damaged by aphids was lower in plots into which either adults or adults and larvae of H. axyridis had been released. These results suggest that both adults and larvae of this flightless strain of H. axyridis are effective in controlling aphids on plants of non-heading Brassica cultivars.     

Oral Fimbriae and Papillae in Parasitic Lampreys (Petromyzontiformes)

There are 38 species of living lampreys, 18 parasitic and 20 nonparasitic. The parasitic species feed as adults, while the nonparasitic do not. The taxonomy and systematics of the living lampreys is based primarily on dentition characters. Since the number of oral fimbriae and oral papillae have never been systematically investigated in lampreys, we compared them in 17 of the 18 parasitic lampreys to assess their usefulness as taxonomic characters. Both showed little variation with total length and sex within a species, while exhibiting greater variation between species. Parasitic species belonging to the three lamprey families could be distinguished using the number of oral fimbriae: southern hemisphere Mordaciidae (0) and Geotriidae (55–65) and northern hemisphere Petromyzontidae (81–144). However, the taxonomic usefulness of the two characters at the species level was limited. Ten out of the 17 species of parasitic lampreys were placed into four distinct groups based on their numbers of oral fimbriae, and only in two of these was the character diagnostic. Twelve out of the 17 species were placed into two distinct groups based on their numbers of oral papillae and for none of these was the character diagnostic. Blood feeders and intermediate feeders (blood + flesh) were shown to have significantly higher numbers of oral fimbriae than flesh feeders. The higher numbers of oral fimbriae in the former two types of feeders were presumed to be linked to their greater need to create a good seal for feeding purposes. Blood feeders were also shown to have significantly higher numbers of oral papillae than either intermediates or flesh feeders. The higher numbers of oral papillae in the blood feeders were presumed to be linked to their greater need to find suitable attachment sites for feeding purposes.     

Distribution and abundance of adult Opomyza florum (Diptera: Opomyzidae) in cereal crops and grassland

From 1971 to 1979 counts were made of the numbers of Opomyza florum adults found in vacuum net samples taken from cereal and grass fields on a 62-km² study area in West Sussex. In 2 years, 1974 and 1975, counts were made of the numbers of adults found in similar samples taken from hedgerow grasses. In all years, numbers of adults were highest in winter wheat crops; relatively few were found in other autumn- or spring-sown cereals or in grass fields. Mean numbers (/m²) in winter wheat in June varied from 33.0 in 1974 to only 0.9 in 1977. In most years, the first adults were found in June in winter wheat; numbers reached a peak in July and then declined rapidly. More adults were usually found in winter wheat crops that followed winter wheat in the rotation than in those following grass. Adults were also more abundant in June in winter wheat crops sown relatively early than in those sown late. The current tendencies towards earlier drilling of winter wheat and to the growth of successive wheat crops could increase the pest status of O. florum.     

The causes of seasonal changes in numbers of the yellow dung fly, Scathophaga stercoraria (Diptera: Scathophagidae)

ABSTRACT. 1. Counts of adult Scathophaga stercoraria (L.) on cow pats were made in Houghall, County Durham, in 1964 and 1965.
2. A spring peak of numbers was due to adults (overwintered mainly as pupae or larvae) maturing and going to dung to breed. Numbers then dropped, rising to one or more peaks in late June—early July. In 1964 there was then a summer drop in numbers until late September. In 1965 high numbers persisted in summer associated with cooler, wetter weather. Autumn peaks in both years persisted until severe frosts or snow.
3. Mature adults, developed from eggs laid during the spring peak, form the first generation when breeding in mid-late June. No clear generations can be identified after this, due to eggs being laid daily (females have successive gonotrophic cycles). Changes in adult numbers breeding reflects survival of eggs and newly-hatched larvae 5–6 weeks earlier, and lower survival rates of adults in mid-summer compared with spring and autumn.
4. Adult Scathophaga numbers in vegetation rose as numbers on dung dropped. Females dissected to count ovariole tunica dilatations showed that most flies in vegetation were immature, with some parous flies hunting insects to develop the next batch of eggs.
5. Females on dung were dissected and found to range from immature to seven-parous. Those gravid for the first time were grossly under-represented, possibly due to wider dispersal.
6. It is suggested that seasonal changes in this r-strategist cannot be explained simply in terms of generations nor by the occurrence of adult diapause.     

Group composition and population density of rhesus monkey (Macaca mulatta (Zimmermann)) in northern India

A field survey of road-side rhesus monkey of northern India was conducted during 1964–65 for the study of group composition and population density. In 1651 km distance covered during this survey, total of 83 groups of rhesus monkey were counted. Adult females were predominant over other members in the group and were twice the number of adult males in a group. Infants were more than double the numbers of juveniles and juveniles formed the smallest percentage in any group and showed a tendency of decline in their population. Percentages of group size varied from 2.50 to 28.09. Sex-ratios, proportions of infants and juveniles to adults, proportions of juveniles to infants and the population density in different zones and sectors have been discussed.     

Biocontrol of almond bark beetle (Scolytus amygdali Geurin-Meneville, Coleoptera: Scolytidae) using Beauveria bassiana (Bals.) Vuill. (Deuteromycotina: Hyphomycetes)

AIMS: To formulate the entomopathogenic fungus Beauveria bassiana in invert emulsion, then apply it against adults of almond bark beetle (Scolytus amygdali) under laboratory and field conditions. METHODS AND RESULTS: The effect of formulated B. bassiana in invert emulsion against S. amygdali adults was shown by comparing the mortality percentage of adults exposed to the formulated fungus using a Petri dish treatment method and by field applications to infested peach trees with mortality of adults exposed to the unformulated fungus or the untreated control. Results obtained from both exposure methods have indicated that treatment of S. amygdali adults with the formulated fungus resulted in a significantly higher mean mortality percentage (P < 0.05) when compared with the treatment with the unformulated fungus or the untreated control. This mortality ranged from 81.2 to 100%, 10 days after treatment with the formulated fungus when compared with 6.7 to 49.6% mortality, 10 days after treatment with the control or the unformulated fungus, respectively. Viability of the fungus conidia in invert emulsion was assessed by calculating the germination percentage of the conidia over time. Results indicated a high storage stability shown by a small loss of germination percentage for the formulated conidia of both strains (5.8 to 8.4% over a 12-week period) vs a low storage stability shown by a high loss of germination percentage for the unformulated conidia of the same strains (58.9 to 61.0% over the same period). The presence of B. bassiana in the galleries of beetles following the treatment of infested trees was shown in the present research. CONCLUSIONS: The results obtained have demonstrated a significantly higher level of efficacy of formulated B. bassiana in invert emulsion against S. amygdali adults under laboratory and field conditions. The ingredients of invert emulsion used in the formulation of the fungus had a negligible effect on the viability of formulated conidia when compared with the unformulated. SIGNIFICANCE AND IMPACT OF THE STUDY: Results obtained in the present research are promising and may be exploited commercially to control S. amygdali adults on various species of stone fruit trees, especially peach trees. This type of biocontrol of this insect may be used as an alternative means to chemical control for management of the insect. No adverse environmental impacts of the fungus or its formulation have been observed during application.     

Seasonal and yearly change in adult abundance of a predacious ladybird <Emphasis Type="Italic">Serangium japonicum</Emphasis> (Coleoptera: Coccinellidae) and the citrus whitefly <Emphasis Type="Italic">Dialeurodes citri</Emphasis> (Hemiptera: Aleyrodidae) in citrus groves

Serangium japonicum Chapin (Coleoptera: Coccinellidae) chiefly attacks whiteflies. This study monitored the adult occurrence of the ladybird and the citrus whitefly Dialeurodes citri (Ashmead) (Hemiptera: Aleyrodidae) in citrus groves in central Japan using sticky traps, thereby examining temporal relationships in their abundance. Many S. japonicum adults were captured in a pesticide-free grove where D. citri adults were very abundant, with few adults in neighboring (organic, reduced pesticide, and conventional) groves harboring small numbers of D. citri. The whitefly adults exhibited a large peak in numbers in late May to early June. Two peaks of the ladybird adult numbers were detected in late May to early June and late June to mid-July, ?6 to 7 days, and nearly 1 month after the peak in whitefly adult numbers, respectively. The ladybird adults found during the first peak period would be those that visited citrus trees mainly for oviposition, and the adults caught during the second peak period would be those that newly emerged after consuming immature whiteflies at the larval stage. Based on a yearly change in adult numbers in the pesticide-free grove, i.e., a large increase in S. japonicum numbers followed by a rapid decline in D. citri numbers, the ladybird’s role in controlling the whitefly is discussed.     

下调烟粉虱MED隐种BtabCSP6表达对番茄黄化曲叶病毒传播的影响

【目的】番茄黄化曲叶病毒(tomato yellow leaf curl virus, TYLCV)是对农业生产造成威胁的主要病毒之一,自然条件下通过媒介昆虫烟粉虱Bemisia tabaci传播。已有研究表明烟粉虱雌成虫比雄成虫具有更强的获毒与传毒能力。本研究旨在探明烟粉虱化学感受蛋白(chemosensory protein, CSP)基因BtabCSP6表达对病毒传播的影响,为控制病毒发生寻找新途径。【方法】使用TYLCV侵染性克隆方法获得带毒番茄植株,微虫笼收集不带毒烟粉虱MED隐种成虫固定在感染TYLCV的番茄植株叶片获毒48 h;利用RT-qPCR技术测定分别取食感染和未感染TYLCV番茄植株的烟粉虱MED隐种雌雄成虫体内BtabCSP1-8基因表达量变化;通过饲喂法利用RNAi对烟粉虱MED隐种雌成虫BtabCSP6基因进行干扰48 h后饲喂TYLCV感染的番茄植株,测定烟粉虱MED隐种雌成虫的获毒率和传毒率。【结果】RT-qPCR检测结果表明,与未侵染的烟粉虱MED隐种雌成虫相比,侵染TYLCV的雌成虫体内BtabCSP3和BtabCSP6基因的表达量变化最为显著。同样...     

A seroepidemiologic survey of three pronghorn (Antilocapra americana) populations in southeastern Idaho, 1975-1977

Sera from 104 adult and 42 fawn pronghorn antelope (Antilocapra americana) from southeastern Idaho were tested against selected livestock pathogens. The numbers positive/numbers tested (% positive) were as follows: bovine virus diarrhea - adults 2/102 (2), fawns 0/41 (0);; infectious bovine rhinotracheitis - adults 27/101 (27), fawns 9/42 (22); parainfluenza 3 - adults 79/104 (76), fawns 22/42 (52); bovine adenovirus 7 - adults 42/103 (41), fawns 20/48 (48); bovine adenovirus 3 - adults 11/32 (34), fawns 4/14 (23); Anaplasma marginale - adults 1/104 (1), fawns 1/42 (2). There were no reactors to brucellosis, bluetongue, or epizootic hemorrhagic disease; The prevalence of reactors varied considerably for different locations and for different years.     

Pooled umbilical cord blood as a possible universal donor for marrow reconstitution and use in nuclear accidents

Human umbilical cord blood has been shown to be an effective source of stem cells for marrow reconstitution in pediatric patients. Unfortunately, the quantity of stem cells obtained from an individual donor can be quite limited in both the total volume and the numbers of stem cells per ml of cord blood. HLA matching further limits the availability, but recent publications indicate close matching may be unnecessary. Therefore, if cord blood from different donors can be combined, larger numbers of stem cells can be available for clinical use provided pooling does not produce a negative effect. Storage of single cord blood specimens at 4 degrees C for 10-21 days in gas permeable bags produced an apparent increase in the percentage of immature cells (CD34, CD117, GPA) and mitotic activity (S+G2/M cells) over day 1. With similar storage of pooled specimens there was a further increase in the number of immature colonies cultured, CD34, CD117, GPA, S+G2/M cells. In addition, nucleated red blood cells increased over the mean values obtained from single cord blood samples. Our previous studies have indicated that large numbers of human mononuclear cells are necessary to reconstitute an irradiated animal model. By combining multiple samples of human cord blood, adequate numbers of stem cells could be pooled for use in adults and would provide cells for megadose therapy, including those patients that had accidentally received lethal irradiation.     

Post-migratory care of young by Crab Plovers Dromas ardeola

The Crab Plover Dromas ardeola is the only waterbird species known to provision offspring well after the post-reproductive migration and through overwintering. A few previous quantitative studies have reported inconclusively that juveniles begged rarely, and also indiscriminately at other juveniles. Here, we describe the feeding behaviour of adult and juvenile Crab Plovers during the first part of the wintering period. Juveniles begged frequently for food, always toward adults, and obtained 0.1 prey items/min from them. Begging birds obtained the largest prey items of those captured by the adults. When foraging alone, juveniles captured prey at the same rate as adults, but captured smaller crabs. The feeding success of adults was not altered by the presence of the begging juvenile. Juveniles depended partly on adults during the first part of the overwintering period, but were almost independent towards the end. Crab Plovers may adopt such unusually prolonged care because they need to abandon their breeding areas quickly, when environmental conditions are extreme. Large numbers of Crab Plovers overwinter in a few areas, now subject to human alteration. Isolated adults may forage on other areas such as narrow and disturbed shores, but juveniles may require wide beaches, suitable for group foraging, that should be considered as key areas for the recruitment of juveniles into the population.     

Spatial and temporal separation of littoral zone fishes of Lake Geneva (Switzerland-France)

The spatial (distance from the shore) and seasonal (summer-winter) distributions of the ichtyofauna in the littoral zone of Lake Geneva were studied between October 1991 and December 1992. Gill nets were set simultaneously at three different sites of a chosen littoral zone: shore, middle and far (50, 300 and 550 m from the shore, respectively).The results show that in summer more species and individuals are present in the littoral zone than in winter. Throughout the year, species richness is greater at the shore site than at the middle or far site. In summer, total abundance is greater at the far site, whereas there are more fish at the shore site during winter. Perch (juveniles and adults), roach and gudgeon (adults only), have maximum abundance during the summer, while lake trout, grayling and whitefish (adults) have maximum abundance during the winter. For five species (adults only) the site comparison shows spatial segregation of the habitats: greater numbers of perch are present at the far site while roach, tench, lake trout and grayling prefer the shore site.     

Utilization of early soybeans for food and reproduction by the tarnished plant bug (Hemiptera: Miridae) in the delta of Mississippi

Commercially produced maturity group (MG) IV soybeans, Glycine max L., were sampled during bloom for tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois), during May and June 1999 (3 fields) and 2001 (18 fields). The adults and nymphs were found primarily in single population peaks in both years, indicating a single new generation was produced during each year. The peak mean numbers of nymphs were 0.61 and 0.84 per drop cloth sample in 1999 and 2001, respectively. Adults peaked at 3.96 (1999) and 3.76 (2001) per sweep net sample (25 sweeps). Tests using laboratory-reared and field-collected tarnished plant bugs resulted in very poor survival of nymphs on 16 different soybean varieties (MG III, one; IV, four; V, nine; VI, two). A large cage (0.06 ha) field test found that the number of nymphs produced on eight soybean varieties after mated adults were released into the cages was lower than could be expected on a suitable host. These results indicated that soybean was a marginal host for tarnished plant bugs. However, the numbers of adults and nymphs found in the commercially produced fields sampled in the study may have been high enough to cause feeding damage to the flowering soybeans. The nature of the damage and its possible economic importance were not determined. Reproduction of tarnished plant bugs in the commercially produced early soybean fields showed that the early soybeans provided tarnished plant bugs with a very abundant host at a time when only wild hosts were previously available.     

Rates of population increase, abundance, and life stage distribution of Rhynchites cribripennis (Coleoptera: Attelabidae) on trees and in the soil in an olive grove

The seasonal population abundance of Rhynchites cribripennis (Desbrochers) adults on olive trees was studied by collecting samples from an olive grove on the island of Zakynthos, Greece, from April 1994 to the end of July 1995. Moreover, the population abundance of larvae, pupae, and adults of R. cribripennis was recorded in soil samples from two soil depths (0-4 and 4-8 cm) from October 1994 to October 1995. Results showed that adult populations increased considerably on trees during May and June and peaked on 16 June (19.9 adults per twig) and 8 July (7.7 adults per twig) in 1994 and 1995, respectively. In 1994, no significant differences were found in the number of adults sampled from the different tree quadrants (northwest [NW], northeast [NE], southwest [SW], and southeast [SE]). However, in 1995, adult numbers in the NW quadrant of trees were significantly higher than those in the SE or SW quadrants. In soil samples, larvae were recorded throughout the sampling period with the highest numbers occurring in December, 2.4 larvae per soil sample, whereas pupae were found in lowest numbers in October and November. Adults were present in the soil samples from December to May, but the highest numbers were recorded in December, with a peak of one adult per sample. The number of adults was significantly higher, and that of larvae numerically higher, in the upper compared with lower soil layer, whereas pupae were found with similar numbers in both soil layers. Results of these studies suggest that this weevil exhibits a prolonged larval diapause and a 2-yr life cycle. The ecological implications of this behavior are discussed. Moreover, a prediction of the highest adult population on trees was estimated by taking into account the rate of increase of adult numbers in the early period of adult occurrence on trees.     

Notes on Thysanoptera found on flax (Linum usitatissimum L.) in the British Isles

The following eighteen species of Thysanoptera Terebrantia have been found on flax in the British Isles: Melanthrips fuscus (Sulzer), Aeolothrips fasciatus (L.), Anaphothrips obscurus (Müler), Aptinothrips rufus (Gmelin), Chirothrips manicatus Hal., Limothrips cerealium Hal., L. denticornis Hal., Stenothrips graminum Uzel, Taeniothrips atratus (Hal.), T. vulgatissimus (Hal.), Thrips angusticeps Uzel, T. discolor Hal., T. flavus Schrank, T. fuscipennis Hal., T. major Uzel, T. minutissimus L., T. physapus L., T. tabaci Lindeman. Each species is described briefly with notes on habits of adults and larvae, place of pupation, number of generations in the year, hibernation, time of occurrence on plants, plants and objects on which found, host plants of larvae and adults, importance to flax, record of locality and collector on flax, distribution, including altitudes, in the British Isles. More species occur in the south than in the north of Great Britain, and species common to both regions usually occur in greater numbers in the south. The insects breed on certain species of crop plants, weeds or trees of arable land. No damage of economic importance to flax by Thysanoptera has been proven in the British Isles, and the flax thrips, Thrips lini Ladureau, has not been found. Taeniothrips vulgatissimus (Hal.) may breed on flax and its adults, and those of T. atratus (Hal.) may cause superficial damage to petals of flowers. Thrips angusticeps Uzel and T. tabaci Lindeman will probably breed on flax.     

空心莲子草叶甲对空心莲子草控制效果的定量评价

为了解空心莲子草叶甲Agasicles hygrophila被引入中国20多年后其取食行为与取食能力是否发生改变, 我们通过采集叶甲自然种群的成虫, 在室内用空心莲子草Alternanthera philoxeroides饲养获得检测用叶甲各虫态与虫量进行室内定量检测, 研究了空心莲子草叶甲自然种群各龄幼虫与成虫在不同密度下对空心莲子草的控害效果。结果显示： 1龄幼虫喜食顶芽嫩叶, 在每株接0.2和1头1龄幼虫密度下, 空心莲子草仍有新叶和侧芽生成, 生物量、 株高与茎节数仍在增加; 在5头/株的密度下, 空心莲子草的生物量、 叶片数和侧芽数均出现负增长; 在10头/株的密度下, 草的生物量、 株高、 叶片数、 侧芽数和茎节数均表现为负增长。2龄幼虫优先取食顶芽嫩叶, 也取食老叶与茎杆, 在每株10头2龄幼虫的密度下, 接虫7 d后, 40%的植株死亡。3龄幼虫取食叶片与茎秆, 后期钻入茎秆中化蛹,在10头/株密度下,7 d后, 已引起52%的植株死亡, 存活株的茎节数显著减少。成虫可24 h连续取食植株的任何组织, 0.2头/株的密度下,空心莲子草叶片与侧芽数量已呈现负增长; 5头/株的密度下,空心莲子草的生物量、 株高、 叶片数、 侧芽数与茎节数均呈现较大的负增长; 10头/株的控草效果更加显著。