The reproductive productivity of the wild rabbit (Oryctolagus cuniculus) in southern England on sites with different soils

Rabbit numbers are rising in most parts of Britain. Previous research in southern England has indicated that the rate of increase in spring due to breeding may vary according to soil type. This has serious implications for the likely rate of invasion into new habitats and for planning control operations. To investigate the hypothesis, post-mortem examinations of over 2500 rabbits from 14 sites on sand, chalk or clay were made. The length of the breeding season and percentage of females breeding differed significantly between soil types but litter size and intra-uterine mortality did not. The product of breeding season length and litter size results in an estimate of annual productivity per adult female. This was 22, 20, and 14 young born per female on clay, chalk, and sandy sites, respectively. Rabbits may invade new habitats, such as set-aside, at different rates according to soil type and therefore require different levels of control regime for population management.     

The ecological effects of the decline in Rabbits (Oryctolagus cuniculus L.) due to myxomatosis

The Rabbit (Oryctolagus cuniculus) population in the British Isles increased rapidly from the 1800s to 1950 due to climatic amelioration, predator reduction and agricultural changes. It became the major vertebrate pest of agriculture, causing an estimated £50 million in damage and lost production each year. Myxomatosis reached Britain in 1954-55 causing 99-9% mortality in some Rabbit populations and, carried by the mosquito and flea vectors, the disease spread rapidly. The consequent decline in the Rabbit population caused dramatic changes in agriculture and the native fauna and flora. It promoted woodland regeneration and increased grassland and cereal production; herb and grass height increased, flowering was noticeable and plant successions ensued. Some small legumes and annual plants became extinct locally and much floristically rich vegetation became dominated by a few grass species or shrubs. The increased grass growth probably promoted an increase in the number of many invertebrate species as well as in the vole (Microrus agrestis). Some species of insect became reduced in number and the Large Blue Butterfly (Maculinea arion) has become extinct (1979) since the decline of the ant (Myrmica spp.) fauna necessary to rear the butterfly larvae. Breeding sites for the Sand Lizard (Lacerta ugilis), Stone Curlew (Burhinus oedicnemus) and Wheatear (Oenanrhe oenanthe) have been reduced by habitat change. Immediately after myxomatosis many predator populations suffered from a lack of Rabbit prey with consequent poor breeding success, but those able to switch to voles, and other predators which are no longer taken in Rabbit trapping, have increased in numbers, e.g. Fox (Vulpes vulpes), Polecat (Mustela putorius), Short-eared Owl (Asio Barnmeus) and Kestrel (Falco tinnunculus). Others such as the Stoat (Mustela ermineu) and the Buzzard (Buteo buteo) declined immediately after myxomatosis through lack of prey and have recovered in nubers only slowly; the Peregrine falcon population has declined partly as a result of lack of open habitat. The breeding success of many predators was also reduced. Parasites of the Rabbit also declined; the flea (Spilopsyllus cuniculi), roundworms and tapeworms, as well as coccidiosis carried by Rabbits and particularly affecting young hares (Lepus europaeus) were all considered to be affected. Species such as the Pheasant Phasianus spp., the hare and the Roe Deer (Capreolus capreolus) increased their use of woodland habitat and/or benefited from the increased food available. Rats (Rartus nomegicus) appeared to decline following increased predation and loss of habitat. In Australia similar vegetational changes occurred in many areas after the introduction of myxomatosis and predators such as the Fox and Wedge-tailed Eagle (Aquila audax) were reduced by control measures following increased predation on sheep. Many bird and marsupial species were reduced in number after the loss of Rabbit prey or on becoming an alternative prey item. In Britain the loss of the fur industry has been outweighed economically by the increased agricultural production and reduced control and maintenance costs following myxomatosis. Since myxomatosis appeared Rabbit numbers have increased only slowly, probably because of increased predator pressure on low density populations and the periodic recurrence of the disease. Rabbit behaviour may have changed so that burrows are not used as much as in the past, Rabbit trapping has ceased and many habitats have been lost. Rabbit numbers could still reach moderate densities but a reversal of many of the ecological effects of my xomatosis is unlikely.     

Dermacentor variabilis: acquired resistance to ticks in BALB/c mice

To assess the ability of Dermacentor variabilis larvae to feed on mice during repeated infestations, known numbers of larvae were confined to the skin of BALB/c mice within plastic capsules, and different skin sites were used in four successive infestations. In secondary infestations larval feeding appeared to be enhanced, but in subsequent infestations the mice expressed acquired tick resistance, manifested by reduction in numbers of engorged larvae and in weights of fed larvae. Resistance, once established, was still demonstrable four weeks after the previous infestation. Histological examination of skin biopsies from BALB/c mice undergoing repeated infestations revealed slight reactions to primary infestations and increasingly severe responses in subsequent infestations. The latter reactions included prominent participation of mast cells and eosinophils, many of which were degranulated close to tick bite sites. It is suggested that these cells might play a role in the expression of murine tick resistance.     

Distribution of Formosan subterranean termite (Isoptera: Rhinotermitidae) in Mississippi

An extensive monitoring and survey program in Mississippi was conducted from 2000 to 2004 to investigate the distribution of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Seventy-two towns from 22 counties in southern Mississippi were monitored with a total of 3914 traps that catch alates during the swarming season. In addition, 259 licensed pest management professionals in Mississippi were surveyed to determine the locations of termite infestations treated. The alates of C. formosanus were recovered in 12 counties with light traps, and termite infestations were documented in an additional 13 from data collected in the termite survey. Infestations of C. formosanus have been documented in urban, urban cluster, rural, and forested areas of Mississippi. However, the distribution in mean total capture of alates for 4 yr differed significantly among the four ecological areas with the highest percentage in forested areas (31%) and the lowest percentage in urban cluster areas (17%). Most of the infestations of C. formosanus were geographically distributed along the coastal areas of southern Mississippi from Gulfport to Pascagoula. The greatest total number of alates captured in light traps was documented in Pearl River County. Mass swarming of C. formosanus occurred primarily in May or June, depending on weather conditions. The number of documented counties with the evidence of large and widely dispersed swarms of C. formosanus in different ecological areas, and the increase in total annual alate captures from 2000 to 2003, suggest that this invasive termite species is now firmly established in Mississippi.     

The population status of Capercaillie Tetrao urogallus in Scotland during winter 2015–16

Capsule: The population size of Western Capercaillie Tetrao urogallus in Scotland was estimated at 1114 individuals with 95% confidence intervals (CIs) of 805–1505.

Aim: To produce an updated estimate of Capercaillie population size in Scotland, with improved precision from, but retaining comparability with, previous surveys.

Methods: A random sample of 2?km long line transects was surveyed throughout the current range of the Capercaillie, during winter 2015–16, with sampling in three separate strata. Multi-covariate distance sampling was used to fit detection functions to the Capercaillie data, deriving national, regional and sex-specific estimates of density and abundance.

Results: Across 741 transects, 136 Capercaillie were recorded in 120 separate encounters, giving rise to a population estimate of 1114 individuals (95% CIs: 805–1505). This estimate is 13% lower than that from the previous survey in 2009–10 but the difference is not statistically significant. Most of the population (83%) was estimated to occur in Strathspey, with much smaller numbers in the rest of the range.

Conclusion: The Capercaillie population in Scotland remains at a critically low level. Further evidence of decline in edge of range subpopulations raises serious concern over the viability of Capercaillie in these areas, whereas numbers appear stable in the core of the range in Strathspey. The use of a revised survey design, with greater sampling in the core of the range, improved estimate precision.     

Uptake of infant and preschool immunisations in Scotland and England during the COVID-19 pandemic: An observational study of routinely collected data

BackgroundIn 2020, the SARS-CoV-2 (COVID-19) pandemic and lockdown control measures threatened to disrupt routine childhood immunisation programmes with early reports suggesting uptake would fall. In response, public health bodies in Scotland and England collected national data for childhood immunisations on a weekly or monthly basis to allow for rapid analysis of trends. The aim of this study was to use these data to assess the impact of different phases of the pandemic on infant and preschool immunisation uptake rates.Methods and findingsWe conducted an observational study using routinely collected data for the year prior to the pandemic (2019) and immediately before (22 January to March 2020), during (23 March to 26 July), and after (27 July to 4 October) the first UK “lockdown”. Data were obtained for Scotland from the Public Health Scotland “COVID19 wider impacts on the health care system” dashboard and for England from ImmForm.Five vaccinations delivered at different ages were evaluated; 3 doses of “6-in-1” diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type b, and hepatitis B vaccine (DTaP/IPV/Hib/HepB) and 2 doses of measles, mumps, and rubella (MMR) vaccine. This represented 439,754 invitations to be vaccinated in Scotland and 4.1 million for England. Uptake during the 2020 periods was compared to the previous year (2019) using binary logistic regression analysis. For Scotland, uptake within 4 weeks of a child becoming eligible by age was analysed along with geographical region and indices of deprivation. For Scotland and England, we assessed whether immunisations were up-to-date at approximately 6 months (all doses 6-in-1) and 16 to 18 months (first MMR) of age.We found that uptake within 4 weeks of eligibility in Scotland for all the 5 vaccines was higher during lockdown than in 2019. Differences ranged from 1.3% for first dose 6-in-1 vaccine (95.3 versus 94%, odds ratio [OR] compared to 2019 1.28, 95% confidence intervals [CIs] 1.18 to 1.39) to 14.3% for second MMR dose (66.1 versus 51.8%, OR compared to 2019 1.8, 95% CI 1.74 to 1.87). Significant increases in uptake were seen across all deprivation levels.In England, fewer children due to receive their immunisations during the lockdown period were up to date at 6 months (6-in-1) or 18 months (first dose MMR). The fall in percentage uptake ranged from 0.5% for first 6-in-1 (95.8 versus 96.3%, OR compared to 2019 0.89, 95% CI 0.86– to 0.91) to 2.1% for third 6-in-1 (86.6 versus 88.7%, OR compared to 2019 0.82, 95% CI 0.81 to 0.83).The use of routinely collected data used in this study was a limiting factor as detailed information on potential confounding factors were not available and we were unable to eliminate the possibility of seasonal trends in immunisation uptake.ConclusionsIn this study, we observed that the national lockdown in Scotland was associated with an increase in timely childhood immunisation uptake; however, in England, uptake fell slightly. Reasons for the improved uptake in Scotland may include active measures taken to promote immunisation at local and national levels during this period and should be explored further. Promoting immunisation uptake and addressing potential vaccine hesitancy is particularly important given the ongoing pandemic and COVID-19 vaccination campaigns.

Fiona McQuaid and colleagues assess the uptake of infant and pre-school immunisations in Scotland and England during the COVID-19 pandemic.     

Can predators regulate wild Rabbit Oryctolagus cuniculus population density in England and Wales?

Predation has usually been interpreted as being a compensatory mortality factor, removing only the doomed surplus. The literature on the wild Rabbit Oryctolagus cuniculus L. is reviewed to collate counter-evidence for a regulating influence of predation. This evidence is almost entirely circumstantial, not experimental. Predation has been reported to extend the length of time Rabbit populations remain low following a significant reduction of Rabbits by some other agent. Rabbit populations have been shown to increase very rapidly when predator density has suddenly been reduced. It has been suggested that predators affect the spread and dispersion of Rabbits both at the geographical and local levels. Predation has not, however, been shown to have an important influence at high Rabbit densities. Thus, its role can be that of a limiting factor rather than a density-dependent regulatory mortality factor. The concept of predator pressure is presented and discussed, pointing out that there is currently no standard technique used for its measurement. Further evidence on the importance of predation is presented from four recent studies in England and Wales that relate, by association, the distribution and abundance of local Rabbit populations to the local attitude towards predators. Rabbits were found to be significantly more widespread and abundant where predators were removed (not restricted to keepered game estates) or at low density, than when predators were undisturbed or at a high density. The significance of these results is discussed. The circumstantial and corroborative evidence leads strongly to the conclusion that predator pressure can act as an additive rather than compensatory mortality factor in some circumstances, and can thus be a potential regulating factor. Predation is more likely to be a limiting factor at low Rabbit density however, since a density-dependent relationship has not been demonstrated throughout the range of Rabbit densities that occur. This requires experimental demonstration to determine the threshold pressure below which predation becomes limiting. If so, reductions in Rabbit populations by short-term control operations could allow natural predation to help maintain low Rabbit densities for several years in some habitats. Conversely, the implications for Rabbit populations and thus crop damage resulting from predator control (e.g. in game management regimes) should be appreciated.     

The relationship between Red-Billed Chough Pyrrhocorax pyrrhocorax (L) breeding populations and grazing pressure on the Calf of Man

A link between the numbers of Loghtan Sheep Ovis aries var. and breeding pairs of Red-Billed Choughs Pyrrhocorax pyrrhocorax has been described for the Calf of Man, Isle of Man, UK, through the analysis of data from 1969 to 1982. Recent research has included further data on populations of Choughs and Sheep grazing, as well as data on brood sizes, Rabbit Oryctolagus cuniculus populations and summer rainfall. Data from 1969 to 1994 show a significant relationship between Sheep and Chough numbers, although data for the period 1983 to 1994 in isolation show no significant association. The mean (± se) brood size ringed in the nest in the period 1959–94 was 2.91 ± 0.011. Between 1972 and 1994, as Sheep numbers peaked, mean brood size decreased, only to rise again as Sheep numbers declined. High Rabbit populations correspond statistically with large Chough broods and increased fledging success. Declines in the Chough breeding population appear to be most closely linked to declines in Rabbit numbers due to outbreaks of myxomatosis, even during periods when Sheep numbers were maintained. The recovery of the Chough population after 1970 corresponds with a change in the effects of myxomatosis outbreaks. Rabbit grazing appears to be equally as important as Sheep grazing in the maintenance of the sward characteristics favoured by breeding Choughs. Combined data on Sheep and Rabbit grazing describe the fluctuations observed in Chough breeding success more fully than data for either grazer alone.     

Prevalence, risk factors and economic importance of infestations with Sarcoptes scabiei and Haematopinus suis in sows of pig breeding farms in Hesse, Germany

A cross-sectional survey was performed in 110 randomly selected pig-breeding farms of southern Hesse, Germany to estimate the prevalence of ectoparasite infestations and to find possible risk factors. Ear scrapings of, if available, 10 sows per farm were examined for Sarcoptes scabiei var. suis (De Geer) (Acaridida: Sarcoptidae) by the potassium hydroxide digestion method, and a total of 2754 sows was inspected for skin lesions and infestations with Haematopinus suis (L.) (Anoplurida: Haematopinidae). Data on farm profiles and sows were collected by a questionnaire. In total, 19.1% and 2.5% of the sows were found to be infested with S. scabiei or H. suis, respectively. The percentage of mite or louse infestation was significantly higher in sows showing pruritus than in those without skin lesions. Both ectoparasite infestations were related neither to the age of sows nor their reproduction status, nor to the time interval to last ectoparasite treatment. Using farms as the unit of analysis, the estimated prevalence of mange mite and louse infestations was 45.4% and 14.5%, respectively. There was no significant association between the presence of S. scabiei and H. suis in the farms. Risk factors for S. scabiei infestation were mixed housing of dry and nursing sows in the same unit (vs. separate housing) and straw bedding (vs. strawless). For louse infestation, only mechanical cleaning of stable units (vs. additional use of disinfection methods) and pasturing of gilts and dry sows were identified as risk factors. The economic loss by S. scabiei infestation in the study population was assessed at euro 4200 per affected farm and year on average.     

Impact of the Biological Control Agent Gyranusoidea tebygi Noyes (Hymenoptera: Encyrtidae) on the Mango Mealybug, Rastrococcus invadens Williams (Homoptera: Pseudococcidae), in Benin

The distribution of Rastrococcus invadens among different host plants and the impact of the mealybug on mango growth were investigated on 2067 trees in three surveys across all the ecological zones of Benin. The first survey started in 1989, less than 1 year after the first release of the exotic parasitoid Gyranusoidea tebygi. Within 3 years, G. tebygi had colonized the entire area of infestation, and was found on practically all infested mango trees as well as other infested host plants. By 1991, the incidence of R. invadens on the secondary host plants had declined significantly. The percentage of infested mango trees declined from 31.0% in 1989 to 17.5% in 1991, highest populations being found in the coastal savanna. During the same period, the mean percentage of infested mango trees having indigenous predators declined from 42.3 to 20.9%. Average mealybug densities declined steadily from 9.7 females/48 leaves in 1989, with 3.2% of all mango trees having densities above 100 mealybugs, to 6.4 females/48 leaves in 1991, with 1.3% of all trees having densities above 100 mealybugs. In multiple regression analyses, based on 23 meteorological, agronomic and plant variables, the duration of the parasitoid's presence proved to be a major factor. It influenced mealybug population densities and sooty mould incidence, which, in turn, affected the production of new leaves. In all analyses, the impact of rainfall, for example, on the sooty mould or the mealybug was less important than the effect of G. tebygi. The present study demonstrates for the first time on a large scale the impact of G. tebygi on R. invadens and, indirectly, on its main host plant, mango.     

Development of selective aphicide treatments for integrated control of summer aphids in winter wheat

Field experiments on the use of recommended and reduced application rates of aphicides for control of summer aphid infestations on winter wheat have been done at five sites each year from 1990 to 1992. The experiment compared sprays of pirimicarb at recommended rate (140g a.i. ha^-1) and reduced rate (25 g a.i. ha^-1) and of alphacypermethrin at recommended rate (15 g a.i. ha^-1) and one third recommended rate (5 g a.i. ha^-1), each applied either at flag leaf emergence or at flowering. Aphid infestations were allowed to develop naturally and were measured at critical growth stages. In 1990, overwintered aphid infestations, together with established populations of parasitoids, were detected at four of the five sites when the first assessment was made in April. Parasitoids provided sufficient aphid control to prevent yield loss at two sites, without pesticide applications. At three sites both aphicides gave similar levels of control and yield response at both recommended and reduced application rates. In 1991 and 1992 no overwintered aphids were detected in the crops and aphid infestations developed much later. Aphicide applications gave significant yield responses at four sites in 1992. Recommended rates gave better control of aphids than reduced rates. There was no significant difference in the yield response obtained with different rates of aphicide.     

Short-term effects of rabbit grazing on a degraded short- tussock grassland in Central Otago

Rabbits are serious economic and environmental pests in New Zealand's semi arid lands, yet there is surprisingly little quantitative information about their grazing impacts. This paper describes the shortterm gains in pasture yield following protection from rabbit grazing in a rabbit-prone, dry tussock grassland community in Central Otago. During the four most productive plant growing months of 1994 (September to December), a six-fold increase in pasture yield was observed after protection from rabbit grazing (139 kg dry weight ha(-1) with rabbits cf. 853 kg DW ha(-1) without rabbits). Rabbit counts were 30 to 42 rabbits per spotlight km. The following four months (January to April) were characterised by reduced pasture growth (3 kg DW/ha with rabbits cf. 337 kg DW ha(-1) without rabbits) and higher rabbit numbers (42-76 rabbits per spotlight km), and was a critical period of herbage depletion. These substantial differences in pasture yield indicate the potential benefits for pastoral production and land conservation following protection from rabbits.     

Deprivation and mortality in Scotland, 1981 and 1991.

OBJECTIVE--To compare the mortality experience of Scottish postcode sectors characterised by socioeconomic census variables (Carstairs scores) in 1980-2 and 1990-2. METHODS--Variables derived from the 1981 and 1991 censuses were combined according to the method devised by Carstairs and Morris to obtain Carstairs scores for 1010 postcode sectors in Scotland in 1981 and 1001 sectors in 1991. For most analyses, these scores were grouped into seven deprivation categories ranging from affluent (category 1) to deprived (category 7) localities. MAIN OUTCOME MEASURES--Death rates and standardised mortality ratios for localities according to deprivation category. RESULTS--Postcode sectors in Scotland that were categorised as deprived in 1981 were relatively more deprived at the time of the 1991 census; the mortality experience of deprived localities relative to either Scotland or affluent neighbourhoods worsened over this period, with a 162% difference between the most affluent and most deprived categories in 1991-2. Although the age and sex standardised mortality for ages 0-64 in Scotland declined by 22% during the 1980s, the reduction in the deprived categories was only about half that of the affluent groups. Increases in the death rate for men (29%) and women (11%) aged 20-29 in the deprived groups were largely attributable to an increase in the rates of suicide. Death rates from ischaemic heart disease and carcinoma of the lung and bronchus at ages 40-69 were lower in all deprivation categories in 1990-2, but the reduction was greater in more affluent areas; the difference in rates for these conditions between affluent and deprived groups therefore increased over the decade. The observed worsening of the standardised mortality ratio for Glasgow relative to Scotland could be explained on the basis of these mortality differentials and the concentration of deprived postcode sectors in Glasgow. CONCLUSIONS--Differences in mortality experience linked to relative poverty increased in the 10 years between 1981 and 1991 censuses. Although mortality for Scotland as a whole is improving, the picture is one of an increasing distinction between the experience of the majority and that of a substantial minority of the population.     

Animal in vivo models of EBV-associated lymphoproliferative diseases: special references to rabbit models

Animal models of human EBV-associated diseases are essential to elucidate the pathogenesis of EBV-associated diseases. Here we review those previous models using EBV or EBV-like herpesviruses and describe the details on our two newly-developed rabbit models of lymphoproliferative diseases (LPD) induced by simian EBV-like viruses. The first is Cynomolgus-EBV-induced T-cell lymphomas in rabbits inoculated intravenously (77-90%) and orally (82-89%) during 2-5 months. EBV-DNA was detected in peripheral blood by PCR from 2 days after oral inoculation, while anti-EBV-VCA IgG was raised 3 weeks later. Rabbit lymphomas and their cell lines contained EBV-DNA and expressed EBV-encoded RNA-1 (EBER-1). Rabbit lymphoma cell lines, most of which have specific chromosomal abnormality, showed tumorigenicity in nude mice. The second is the first animal model for EBV-infected T-cell LPD with virus-associated hemophagocytic syndrome (VAHS), using rabbits infected with an EBV-like herpesvirus, Herpesvirus papio (HVP). Rabbits inoculated intravenously with HVP-producing cells showed increased anti-EBV-VCA-IgG titers, and most (85%) subsequently died of fatal LPD and VAHS, with bleeding and hepatosplenomegaly, during 22-105 days. Peroral spray of cell-free HVP induced viral infection with seroconversion in 3 out of 5 rabbits, with 2 of the 3 infected rabbits dying of LPD with VAHS. Atypical T lymphocytes containing HVP-DNA and expressing EBER-1 were observed in many organs. Hemophagocytic histiocytosis was observed in the lymph nodes, spleen, bone marrow, and thymus. These rabbit models are also useful and inexpensive alternative experimental model systems for studying the biology and pathogenesis of EBV, and prophylactic and therapeutic regimens.     

The status of the Hen Harrier,Circus cyaneus,in the UK and Isle of Man in 2010

Capsule The fourth national survey of Hen Harrier showed that the population in the UK and the Isle of Man declined significantly between 2004 and 2010.

Aim To estimate the size of the breeding Hen Harrier population (with associated 95% confidence intervals) in the UK and Isle of Man, constituent countries and Scottish regions, in 2010 and calculate population change since previous surveys in 1998 and 2004.

Methods Complete surveys were made of 10-km squares likely to be occupied by breeding Hen Harriers in England, Wales, Northern Ireland and the Isle of Man, using standard methods developed for previous national surveys. In Scotland, a ‘census’ area was non-randomly selected for survey by volunteers, and randomly selected squares were surveyed in two strata covering the rest of the known range.

Results The UK and Isle of Man Hen Harrier population was estimated at 662 territorial pairs (95% confidence interval (CI): 576–770), a significant decline of 18% since 2004. Scotland holds the bulk (76%) of the population (505 territorial pairs; 95% CI: 417–612), with smaller numbers in Northern Ireland (59 pairs), Wales (57 pairs), the Isle of Man (29 pairs) and England (12 pairs). Declines of 49% and 20% were observed in the Isle of Man and in Scotland, respectively, whereas the Welsh population increased by 33%. A significant decrease was recorded in numbers of pairs using young and mature plantation forest in Scotland.

Conclusion The breeding population of Hen Harriers in the UK and Isle of Man declined between 2004 and 2010. Notable decreases in Scotland and the Isle of Man may be related to habitat change and illegal persecution. Illegal persecution continues to limit the population size of harriers in England to very low levels.     

Progress towards a biological control programme for glasshouse whitefly (Trialeurodes vaporariorum) on tomatoes

During 1969/74 different methods of using the parasite Encarsia formosa to control whitefly infestations on tomatoes in glasshouses have been evaluated commercially. The most effective control was achieved by the Glasshouse Crops Research Institute (GCRI) programme of timed parasite introductions at rates totalling 120000 parasites per ha (48000/acre) following the pre-establishment of a low, evenly distributed infestation of the pest throughout the crop. Other methods, including the regular introduction of parasites after planting in anticipation of a whitefly infestation or starting when the first whiteflies appear on the plants, are also described. These multiple introduction (‘dribble’) methods, gave mostly satisfactory control but were less predictable. The efficiency of the parasite is greatly impaired during the short days and low light intensities of the late winter months and alternative methods of dealing with early whitefly infestations, including the use of chemicals, are discussed.     

Breeding season diet of the Goshawk Accipiter gentilis in Wales

Information on the diet of the Goshawk Accipiter gentilis during the breeding season was collected in Wales during 1991–1993. Diet consisted mainly of birds (87%) and mammals (13%). Forty-five prey species were collected, ten of which were important in numerical or biomass terms: Feral Pigeon Columba livia , Woodpigeon Columba palumbus , Crow/Rook Corvus coronet Corvus frugilegus , Magpie Pica pica , Jay Garrulus glandarius , Mistle Thrush Turdus viscivorus , Song Thrush Turdus philomelos , Blackbird Turdus merula , Grey Squirrel Sciurus carolinensis and Rabbit Oryctolagus cuniculus . Pigeon biomass was important throughout the breeding season and was more important in the diet of nesting Goshawks on higher ground (>250 m). On lower ground, corvids, mammals and pigeons were the main contributors to the Goshawk diet. Rabbits were more frequently taken at lower nesting territories, and thrushes occurred at all altitudes. Mammals, particularly Grey Squirrel, were found in higher numbers in the diet of Goshawks nesting in small woods (<1000 ha) compared with the diet of Goshawks nesting in two large forests ( c . 3500 ha and c . 6100 ha). Goshawks preyed upon juvenile Woodpigeons, corvids and thrushes, and switched from young thrushes to young corvids as the latter became available. Predation peaks on young birds corresponded with the presence of nestling Goshawks in late May to early July. Predation of juvenile prey led to a decrease in mean prey item mass (April-May, 437 g; July, 376 g). No evidence was found to suggest that sexual size dimorphism in Goshawks resulted in partitioning of prey captured during the breeding season. Differences found were probably due to local abundance and vulnerability of prey species rather than specific selection by the two sexes.     

Effectiveness of bed bug monitors for detecting and trapping bed bugs in apartments

Bed bugs, Cimex lectularius L., are now considered a serious urban pest in the United States. Because they are small and difficult to find, there has been strong interest in developing and using monitoring tools to detect bed bugs and evaluate the results of bed bug control efforts. Several bed bug monitoring devices were developed recently, but their effectiveness is unknown. We comparatively evaluated three active monitors that contain attractants: CDC3000, NightWatch, and a home-made dry ice trap. The Climbup Insect Interceptor, a passive monitor (without attractants), was used for estimating the bed bug numbers before and after placing active monitors. The results of the Interceptors also were compared with the results of the active monitors. In occupied apartments, the relative effectiveness of the active monitors was: dry ice trap > CDC3000 > NightWatch. In lightly infested apartments, the Interceptor (operated for 7 d) trapped similar number of bed bugs as the dry ice trap (operated for 1 d) and trapped more bed bugs than CDC3000 and NightWatch (operated for 1 d). The Interceptor was also more effective than visual inspections in detecting the presence of small numbers of bed bugs. CDC3000 and the dry ice trap operated for 1 d were equally as effective as the visual inspections for detecting very low level of infestations, whereas 1-d deployment of NightWatch detected significantly lower number of infestations compared with visual inspections. NightWatch was designed to be able to operate for several consecutive nights. When operated for four nights, NightWatch trapped similar number of bed bugs as the Interceptors operated for 10 d after deployment of NightWatch. We conclude these monitors are effective tools in detecting early bed bug infestations and evaluating the results of bed bug control programs.     

Effects of superovulation, culture and microinjection on development of rabbit embryos in vitro

Factors influencing the developmental potential of cultured rabbit zygotes and their ability to incorporate and integrate the WAP-hPC (human protein C) gene were investigated. Rabbit zygotes (n = 1053) were recovered from both superovulated and nontreated New Zealand White females. The hormonal treatment of rabbit donors resulted in a doubling of the number of recovered ova per donor when compared with the nontreated group (18 vs 9 ova). However, the quality of recovered zygotes (presence of both pronuclei) was significantly better in the nontreated group (99 vs 88%, Experiment 1). The effect of various culture media on the development of rabbit zygotes in vitro was evaluated after incubation under CO2-free conditions (Experiment 2). In serum-free, growth factor-supplemented medium (BSEITS, DME/F12, 1.5% BSA, EGF, insulin, transferrin and sodium selenite) the percentage of morula/blastocyst stage embryos was significantly higher (88%) than in DME/FCS, (DME/F12, 10% fetal calf serum, 59%) or the control group (DME/F12, 1.5% BSA, 25%). In Experiment 3, zygotes were microinjected with the WAP-hPC gene and were examined after 72 h of culture. Zygote cleavage and the percentage of morula/blastocyst stage intact embryos were higher (79 and 58%, respectively) than in microinjected embryos (31.0 and 21.5%, respectively). Summarized data of the PCR assay of microinjected zygotes demonstrated positive signals for the integration of the WAP-hPC gene in 6.6% (34 of 515) of all the microinjected zygotes.     

Rabbit populations and game management: the situation after 15 years of rabbit haemorrhagic disease in central-southern Spain

Over recent decades wild rabbit populations have undergone a sharp decline in Spain with consequent negative impact both on a game-based economy, and on the conservation of threatened species that depend on rabbits. We investigated the relationships between rabbit population change and habitat and game management in central-southern Spain. To determine recent rabbit population changes we revisited 60 localities during summer 2002 to repeat surveys previously carried out in 1993. Each survey consisted of 4-km walked transects to record indices of rabbit abundance. The percentage of vegetation cover and of different soil types were also estimated during these transects. In the same areas, the type and intensity of game management practices were obtained by interviewing hunting managers, hunters or gamekeepers. Rabbit populations were stable or increasing only in 26.6% of the studied populations, more commonly in areas with soft soils where warren building is easier for rabbits and where rabbits were an important game species and managed to increase their numbers. Although we could not establish causality, habitat management and predator removal were the main management practices related to rabbit population change. Rabbit scarcity in Spain constitutes a serious problem for conservation, so hunters, researchers and policy makers need to reach a consensus to establish a long-term program to monitor rabbit population trends and share results obtained, especially when intense manage programs are being carried out to improve rabbit abundance.