The use of oxytetracycline as a marker for juvenile cod (Gadus morhua L.)

We examine aspects of marking large numbers of juvenile cod ( Gadus morhua L.) by oxytetracycline (OTC) for cod enhancement experiments. Reared cod were given OTC through the feed and released in a fjord. Control groups were kept in net pens. A total of 93% of the cod became marked. The size of the cod and the percentage marked were inversely related. The location of the mark within each vertebra gradually changed towards the centre as the cod grew and new bone tissue was added. The percentage of marked cod in the control group did not decrease during a period of almost 3 years after marking, although the intensity of the mark gradually declined. After release, we found no indication that the OTC affected growth or survival of the cod. Cod marked as O-group could be distinguished from cod marked as 2-group, from the position of the mark within the vertebra.     

Transformation of Trichothecenes in Ileal Digesta and Faeces from Pigs

The capacity of pig gastrointestinal microflora to metabolise the trichothecenes 3-acetyl-deoxynivalenol (3-acDON) and nivalenol (NIV) was investigated. 3-acDON was deacetylated to DON in anaerobic incubations with pig faeces collected at different pig farms. Furthermore, both 3-acDON and NIV were metabolised to the corresponding de-epoxy metabolite in these incubates. Five pigs, in which the gastrointestinal microflora lacked the ability to transform 3-acDON and NIV to their corresponding de-epoxidated metabolites, were given low levels of DON in the feed for seven weeks. The gastrointestinal micro-organisms did not acquire the de-epoxidation ability during the seven week long exposure period. At the end of the exposure period, faeces from pigs with a known de-epoxidation ability was spread out in the pens and left for 24 hours. One week after the faeces had been spread out in the pens, the de-epoxidation ability was found in faecal incubations from four out of five experimental pigs. This change in metabolic ability of the intestinal de-epoxidation ability was not accompanied by any detectable changes in the DNA-profiles of the bacterial community composition. The results show that the intestinal de-epoxidation ability is common at pig farms in the Uppsala area, and that the ability may be transferred between pigs in a stock.     

Insulin Pen Injection Devices for Management of Patients with Type 2 Diabetes: Considerations Based on an Endocrinologist’s Practical Experience in the United States

ObjectiveTo review the features of several insulin pens currently available in the United States, discuss the validity of concerns about certain pen devices, and provide specific training information for clinicians to increase the accuracy of insulin administration and patient satisfaction with the use of insulin pens.MethodsThe published literature on insulin pens and Internet-available, product-specific information are reviewed. In addition, special practical considerations regarding insulin pen selection based on personal experience in a high-volume endocrinology practice are highlighted by presentation of case vignettes.ResultsFor some patients with diabetes, the need for performance of self-injection can be a barrier to acceptance of insulin therapy. Insulin pen devices provide a delivery option that may be more acceptable and more convenient to use in comparison with traditional vials and syringes and thus may promote patient compliance, which can enhance the ability to achieve and maintain glycemic control. When choosing a specific insulin pen for an individual patient, the clinician should consider the patient’s insulin regimen, lifestyle, and factors that may affect the ability to use a particular device, such as motor dexterity and visual acuity.ConclusionInsulin pens offer convenience and can potentially increase patient satisfaction and compliance with therapy. Because certain characteristics of a given insulin pen may make it preferable for specific patients, it is important for clinicians to be aware of individual needs. Provision of thorough training for patients in the correct use of insulin pens is important because user error can affect pen performance and accuracy of the dose administered. Manufacturers should be notified of any recurring problems. (Endocr Pract. 2007;13:672-678)     

The role of aromatization in androgen stimulation of gerbil scent marking

The androgen dependent scent marking behavior of male Mongolian gerbils (Meriones unguiculatus) can be stimulated after castration by either testosterone or estrogen, but not by dihydrotestosterone (DHT). To determine if DHT fails to evoke scent marking because it cannot be aromatized to form an estrogen, two other nonaromatizable androgens, 1α-methyltestosterone and 6α-fluorotestosterone, were studied. 6α-Fluorotestosterone and its propionate ester stimulated scent marking in castrated male gerbils as effectively as testosterone and its ester did. Hence, an androgen's aromatizability does not determine its ability to influence gerbil scent marking behavior.     

Scent marking in two western Amazonian populations of woolly monkeys (Lagothrix lagotricha)

We describe patterns of scent marking observed in two wild populations of lowland woolly monkeys that were the subjects of long-term studies in the westernmost portion of the Amazon basin. The woolly monkeys engaged primarily in two types of scent marking: chest rubbing and anogenital rubbing. In both study populations, males and females performed both types of scent marking, but males chest-rubbed more commonly than females, while females engaged in more anogenital rubbing. We evaluated two nonexclusive hypotheses for the function of scent marking by woolly monkeys: 1) that scent marking is used in sociosexual contexts, and 2) that scent marking is used to convey information about occupancy of or willingness to defend an area from conspecifics in other social groups. We found no association between the occurrence of scent-marking behavior and location within the home range, but did find that scent marking occurred more commonly than expected on days when copulations, mating solicitations, and intergroup encounters were observed. Additionally, mating activity and chest rubbing were highly correlated across the yearly cycle, even when the potentially confounding variable of ripe fruit availability was controlled for. In woolly monkeys, overt male-male competition is rare and female choice is an important part of the mating system. Our results are most consistent with the idea that scent marking plays a role in advertising male quality or competitive ability, and perhaps in coordinating mating activity.     

Prevention and treatment of tail biting in weaned piglets

The aims of this study were to evaluate four preventive measures and two curative treatments of tail biting. The preventive measures were: chain, rubber hose, straw rack (5 g/pig/day) and the provision of straw on the floor twice daily by hand (2 × 10 g/pig/day). The two curative treatments, which were applied following the onset of tail biting in a pen were: straw twice daily (as in the fourth preventive measure) and the removal of the biter. In total, 960 undocked weaned piglets (10 piglets per pen) were observed during 5 weeks. Tail lesions (none, bite marks and wounds) were recorded daily. The incidence of pens with wounded pig tails was significantly lower when straw was provided twice daily (8% of pens) compared to the chain (58% of pens) and rubber hose (54% of pens) treatment, but did not differ significantly from the straw rack treatment (29% of pens). Tails with bite marks were significantly less common in pens with twice daily straw (16% of pens) compared to chain (88% of pens), rubber hose (79% of pens) and straw rack (75% of pens). No significant difference was found between the curative treatments. Both treatments showed a reduced incidence of red fresh blood on the tails at days 1–9 following curative treatment, compared to day 0. However, neither curative treatment eliminated tail biting entirely. In conclusion, this study indicates that tail biting is best prevented with a small amount of straw, provided twice daily, and to a lesser extent with a straw rack, compared to providing a chain or a rubber hose. Once tail biting has occurred, providing a small amount of straw twice daily and removing the biter appears to be equally effective.     

Preslaughter holding environment in pork plants is highly contaminated with Salmonella enterica

The objective of this study was to determine whether abattoir pens can provide a Salmonella enterica infection source during the 2 to 4 h of preharvest holding. Previous work has suggested that pigs may be getting infected, but little has been reported on the environmental contamination of abattoir holding pens. For 24 groups of pigs studied ( approximately 150 animals/group) at two high-capacity abattoirs, six pooled fecal samples (n, 10 per pool) were collected from each transport trailer immediately after pigs were unloaded. Holding pens were sampled (one drinking water sample and six pooled floor samples consisting of swabs, residual liquid, and feces) prior to entry of study pigs for the routine holding period ( approximately 2.5 h). After slaughter, cecal contents and ileocecal lymph nodes were collected, on the processing line, from 30 pigs in each studied group. All samples were cultured for the isolation and identification of S. enterica by primary enrichment in GN-Hajna and tetrathionate broths, secondary enrichment in Rappaport-Vassiliadis broth, and plating on brilliant green sulfa and xylose-lysine-tergitol-4 agars, followed by biochemical and serological identification. The study pens were highly contaminated with S. enterica; all holding pens sampled had at least one positive sample. Additionally, 33% (8 of 24) of drinking water samples were positive for S. enterica. All 24 groups of pigs had S. enterica-positive cecal contents and ileocecal lymph nodes, including those groups from transport trailers with no positive samples. From pigs, trailers, and pens, 586 isolates representing 36 different Salmonella serovars were isolated. Of the 353 isolates from pigs (109 from ileocecal lymph nodes plus 244 from cecal contents), 19% were identified as belonging to the same serovars as those isolated from the respective pens; 27% were identified as belonging to the same serovars as those isolated from the trailers. Sixteen percent of the unique serovars were isolated from both pigs and pens, suggesting that pens served as the infection source. This study demonstrates highly contaminated abattoir holding pens and watering sources. It also demonstrates that holding pens can serve as an infection source. This study identifies the abattoir holding pens as a significant hazard and a potential control point for Salmonella contamination in the preharvest pork production chain.     

An Update on Insulin Injection Devices

Background: Over the past 15 years, it has become clear that better glycemic control can lead to a substantial reduction in diabetic complications and that such control often requires the use of insulin therapy. However, a number of barriers exist to starting such therapy in patients with diabetes mellitus (DM). Many of these barriers to treatment are related to the use of a syringe to inject the medication. In the past ~20 years, various "pen" devices have become available that help to reduce the stigma associated with insulin injection, allowing more patients to achieve the glycemic control that they require.Objectives: This article provides an overview of the various pen devices available in the United States for subcutaneous insulin delivery and discusses the benefits these devices can provide to patients; their disadvantages are also discussed. Third-party reimbursement for these devices is highlighted.Methods: A MEDLINE search was performed (1980-2007) to identify relevant articles (English-language only) using appropriate key terms, including insulin pen and insulin delivery device. Technical specifications and availability information for the various pen devices were obtained directly from their manufacturers. Insurance coverage data were provided by major national insurance carriers.Results: There are a number of excellent pen devices available for administering each of the currently offered basal and bolus insulin analogues as well as neutral protamine Hagedorn and regular insulins. These devices range from disposable pens—which are supplied to the patient prefilled from the pharmacy, used until empty, and then discarded—to refillable digital pens, some of which have the ability to “remember” prior insulin doses. Data from various studies indicate that both patients and their physicians generally prefer insulin pens over the traditional vial and syringe delivery method. These devices are simple to use, allow patients to be more discreet in social situations, can easily be carried in a shirt pocket or purse, do not need to be refrigerated while in use, are associated with a lesser degree of injection anxiety, and may even be more accurate at lower doses. They may also be the preferred delivery system for the visually impaired, given their larger displays and the audible/tactile “click” produced each time the dose is increased by 1 U. Insulin pens lead to increased patient confidence and satisfaction and improved attitude toward insulin therapy. Most major insurance plans provide some coverage for the disposable pens as well as the cartridges for refillable pens, but this is often under tier 2 and some insurers may require prior authorization.Conclusions: Insulin pens provide DM patients with a number of advantages over a vial and syringe and can often help them overcome major barriers to the initiation of insulin therapy. The use of insulin pens leads to increased patient compliance and potential improvements in glycosylated hemoglobin, but data on glycemic control are not available. The pens should be offered to virtually all patients who require insulin therapy, except in instances in which these pens are financially prohibited.     

Preslaughter Holding Environment in Pork Plants Is Highly Contaminated with Salmonella enterica

The objective of this study was to determine whether abattoir pens can provide a Salmonella enterica infection source during the 2 to 4 h of preharvest holding. Previous work has suggested that pigs may be getting infected, but little has been reported on the environmental contamination of abattoir holding pens. For 24 groups of pigs studied (~150 animals/group) at two high-capacity abattoirs, six pooled fecal samples (n, 10 per pool) were collected from each transport trailer immediately after pigs were unloaded. Holding pens were sampled (one drinking water sample and six pooled floor samples consisting of swabs, residual liquid, and feces) prior to entry of study pigs for the routine holding period (~2.5 h). After slaughter, cecal contents and ileocecal lymph nodes were collected, on the processing line, from 30 pigs in each studied group. All samples were cultured for the isolation and identification of S. enterica by primary enrichment in GN-Hajna and tetrathionate broths, secondary enrichment in Rappaport-Vassiliadis broth, and plating on brilliant green sulfa and xylose-lysine-tergitol-4 agars, followed by biochemical and serological identification. The study pens were highly contaminated with S. enterica; all holding pens sampled had at least one positive sample. Additionally, 33% (8 of 24) of drinking water samples were positive for S. enterica. All 24 groups of pigs had S. enterica-positive cecal contents and ileocecal lymph nodes, including those groups from transport trailers with no positive samples. From pigs, trailers, and pens, 586 isolates representing 36 different Salmonella serovars were isolated. Of the 353 isolates from pigs (109 from ileocecal lymph nodes plus 244 from cecal contents), 19% were identified as belonging to the same serovars as those isolated from the respective pens; 27% were identified as belonging to the same serovars as those isolated from the trailers. Sixteen percent of the unique serovars were isolated from both pigs and pens, suggesting that pens served as the infection source. This study demonstrates highly contaminated abattoir holding pens and watering sources. It also demonstrates that holding pens can serve as an infection source. This study identifies the abattoir holding pens as a significant hazard and a potential control point for Salmonella contamination in the preharvest pork production chain.     

Changes in activity and object manipulation before tail damage in finisher pigs as an early detector of tail biting

Tail damage within the production of finisher pigs is an animal welfare problem. Recent research suggests that removal of known risk factors may not be enough to eliminate tail biting, especially in undocked pigs, thus a different strategy is worth investigating. This could be early detection of tail biting, using behavioural changes observed before tail damage. If these early stages of tail biting can be detected before tail damage occurs, then tail damage could be prevented by early interventions. The first step in developing such a strategy is to identify the types of behaviour changes that emerge during early stages of tail biting. Thus, the aim of the current study was to investigate whether pen level activity and object manipulation evolved differently during the last 7 days before the scoring of tail damage (day 0) for pens scored with tail damage (tail damage pens) and pens not scored with tail damage (matched control pens). The study included video recordings for twenty-four tail damage pens and thirty-two matched control pens. Activity level and object manipulation were observed the last 7 days before day 0 during the morning (0600 to 0800 h), afternoon (1600 to 1800 h) and evening (2200 to 2400 h, only activity level). Both activity level and object manipulation were analysed using generalised linear mixed effects models with a binomial distribution for activity level and a negative binomial distribution for object manipulation. The probability of being active was higher in tail damage pens compared to control pens during the afternoon the last 5 days before day 0 (P<0.001). This was seen due to a decrease in activity level in the control pens, which makes it difficult to identify future tail damage pens from this difference. Object manipulation was lower in tail damage pens compared to the control pens on all 7 days before day 0, but only in pens with undocked pigs (P<0.01). Thus, it is still unknown when this difference in object manipulation initiated. It was concluded that both activity level and object manipulation seemed related to ongoing tail biting and should be investigated through more detailed observations and for a longer time to establish the normal behaviour pattern for a particular pen. Thus, it is suggested that future research focusses on developing automatic monitoring methods for pen level activity and object manipulation and applies algorithms that establish and detect deviations from the normal behaviour pattern of the pen before tail damage.     

昆虫寄主标记信息素

综述了昆虫寄主标记信息素的研究进展。昆虫寄主标记信息素是指由昆虫产生的用来标记寄主上有同种个体存在的化学物质。昆虫寄主标记信息素的主要生态学功能是调节昆虫的产卵行为,通过阻止自身或同种其它个体对已标记寄主的产卵选择,或减少产卵量来减少后代之间对寄主资源的竞争。寄主标记信息素也会给释放着带来不利的影响,如信息盗用和盗寄生现象等。昆虫寄主标记信息素也调节昆虫近缘种之间对共同寄主资源的竞争。近缘种昆虫对相互寄主标记信息素识别能力的差异反映了不同昆虫对同一寄主资源竞争能力的强弱。寄主标记信息素产生和贮存的部位一般与外分泌腺、消化系统或生殖系统相联系,杜氏腺、毒腺、前胸腺、腹腺、下唇腺、后产卵管、卵巢、中肠和后肠等是产生或贮存寄主标记信息素的常见部位。产生的寄主标记信息素一般在成虫产卵时由产卵器、口器或排泄口释放到寄主体内或体表。卵寄生蜂的寄主标记信息素一般标记在寄主的体表,雌成蜂用触角检测;其它寄生蜂的寄主标记信息素常产在寄主体内,用产卵器检测;植食性昆虫的寄主标记信息素只产在寄主表面,用触角或产卵器检测。昆虫的产卵器、口器、触角或跗节上着生有感受寄主标记信息素的化感器,可以检测到标记在寄主体内或体表的寄主标记信息素。昆虫寄主标记信息素的完全定性涉及活性化合物的分离、鉴定、合成以及行为测定等,已有几种昆虫的寄主标记信息素成分得到了分离鉴定。     

Effect of pens with an elevated platform on space utilization,skin lesions and growth performance in nursery pigs

Environmental enrichment, adequate space and the ability to separate a living area into suitable functional areas are key elements for pig welfare. In this study, a two-level pen for nursery pigs was explored with the aim of analysing the use of space and the impact on pig behaviour, health and performance. Therefore, per batch, three experimental groups in pens with elevated platforms (two-level pens) and one control group in a standard pen were formed after weaning at the age of 4 weeks. Thereafter, groups were studied for a period of 6 weeks. In a total of eight batches (n = 882 pigs), the occurrence of skin lesions was determined per individual using a lesion score, and in seven batches (n = 761 pigs) individual daily weight gain was analysed. In five batches (n = 450 pigs), the individual use of space and the behaviour of pigs were investigated by direct observation (4 h per day on 2 days in weeks 1, 3 and 6 of the housing period, respectively). Results revealed that 98.9% of pigs (n = 445) were observed on the elevated platform at least once. The probability that an individual pig used the platform was significantly higher than 0.95 (P < 0.0001, confidence interval = 0.977, 1). The use of the platform was not affected by sex (odds ratio (OR) = 1.013, P = 0.937). However, the probability of observing an individual on the elevated platform increased with increasing BW during the experimental period (OR = 1.043, P < 0.0001). The presence of a platform decreased the probability of seeing a pig fighting (P = 0.014) and increased the probability of observing locomotor behaviour as opposed to lying (P < 0.0001). In two-level pens, pigs sustained fewer skin injuries than in standard pens (day 41: OR = 0.731, P < 0.0001). Over 41 days of experiment, pigs in two-level pens had higher daily weight gains than animals in standard pens (416 versus 393 g/day, P = 0.006). We conclude that usable space for nursery pigs can be effectively extended by introducing elevated platforms into the pigs’ pen. Furthermore, pigs may benefit from two-level systems by establishing spaces for activity as well as for retreat from other pen mates, thereby reducing aggressive behaviour and social stress. The installation of two-level pens is therefore encouraged, if they are intended to provide more space than legally stipulated.     

Scent marking in a territorial African antelope: I. The maintenance of borders between male oribi

Scent marking is ubiquitous among the dwarf antelope and gazelles of Africa, but its function has been the subject of debate. This study examined preorbital gland scent marking in the oribi, Ourebia ourebi, a territorial African antelope. Several hypotheses for the function of scent marking by territorial antelope were tested with observational data. Of these, the hypotheses that scent marking is driven by intrasexual competition between neighbouring males, and that marks serve as an honest advertisement of a male's ability to defend his territory from rivals, were supported best. Thirty-three territorial male oribi on 23 territories marked most at borders shared with other territorial males, and territorial males marked more often at borders shared with multimale groups than at borders shared with a single male. This suggests that males perceived neighbouring male groups as a greater threat to territory ownership than neighbouring males that defended their territories without the aid of adult subordinates. Marking rate was unrelated to territory size or the number of females on adjacent territories, but males with many male neighbours marked at higher rates than those with fewer male neighbours. These results suggest that the presence of male neighbours has a greater effect on the scent marking behaviour of territorial antelope than has been considered previously. Copyright 1999 The Association for the Study of Animal Behaviour.     

The effects of operant control over food and light on the behaviour of domestic hens

In intensive farming systems, the animals have little control over important elements in their environments. For instance, food of a pre-set type is delivered at set times, and the lighting schedule is controlled by the farmer. It has been suggested that low levels of environmental control over important events may reduce welfare by increasing passivity and stress. This study aimed to evaluate the effect of providing control over food and lighting additional to a restricted regime on the behaviour of small groups of laying hens (Gallus gallus domesticus). Twelve pens, each containing five birds, were paired to give six controlling and six non-controlling pens. These pairs of pens were yoked, such that birds in the controlling pens were able to make an operant response to gain access to extra food and light, whilst the yoked pens also received these outcomes but were unable to control their occurrence. The birds were kept continuously in the experimental conditions for 9 weeks. Records were made of general behaviour and activity, aggression and plumage damage scores, every 2 weeks. Data on key-pecking and egg production were continuously recorded throughout the experiment. The controlling birds used the operant keys to open the feeder for an average of 92min and to turn on the light for 46min per pen per day. The high number of key-pecks indicates that the birds were motivated to make use of the keys to control access to additional food and light. The non-controlling treatment pens showed significantly higher levels of preening and resting. Contrary to previous studies the use of operant feeders in this experiment did not induce a high level of feather pecking or aggressive interactions, as there was no significant difference between treatments. During the experiment the non-controlling hens laid significantly more eggs than the controlling hens. The results suggest that lack of control over these particular environmental events induced mild stress in the non-controlling pens of birds, and that further investigations into the effect of lack of control on welfare would be warranted.     

A simple pen-spotting method for arraying biomolecules on solid substrates

We describe a simple, relatively inexpensive method for depositing biomolecules on a solid substrate using Rapidograph® drafting pens. The pens can be used without modification to accurately deposit spots between 100 and 600 μm in diameter. When mounted on a suitable microtranslation stage, the pens can be used to easily deposit tens of spots aligned with underlying substrate features such as microfabricated sensors. The pens are particularly convenient because pre-mixed solutions can be stored in the pens for multiple uses. We demonstrate the use of this approach to deposit DNA probes on a microsensor array.     

Light intensity preferences of broiler chickens: implications for welfare

There is considerable debate as to the optimal light intensities for growing chickens. This is influencing regulations and industry practices. The present study examines the preference of broiler chickens for light intensity. A choice system was developed to allow determination of the preferences of broiler chickens for light intensity. This system had three light proof pens each with feeders or waterers but different light intensities. There was a connecting transit pen with a light intensity of 1 to 2 lux. This allowed birds access to the pens each with feeders or waterers. There were markedly more chickens observed in the pens each with feeders or waterers and a light intensity of 20 lux than 5 lux. Moreover, more feed was consumed in the 20 lux pens than 5 pens. There were also high numbers of chickens in the transit compartment with its low light intensity (1 to 2 lux) and no feeders or waterers. Broiler chickens exhibited a preference for 20 lux light intensity for feeding compared to 5 lux light intensity. The present study supports the view that there should be a light intensity of at least 20 lux for the areas around the feeders and also suggests that light intensity may be reduced in other areas for resting and other activities.     

Longitudinal study of fecal shedding of Escherichia coli O157:H7 in feedlot cattle: predominance and persistence of specific clonal types despite massive cattle population turnover

Identification of the sources and methods of transmission of Escherichia coli O157:H7 in feedlot cattle may facilitate the development of on-farm control measures for this important food-borne pathogen. The prevalence of E. coli O157:H7 in fecal samples of commercial feedlot cattle in 20 feedlot pens between April and September 2000 was determined throughout the finishing feeding period prior to slaughter. Using immunomagnetic separation, E. coli O157:H7 was isolated from 636 of 4,790 (13%) fecal samples in this study, with highest prevalence earliest in the feeding period. No differences were observed in the fecal or water trough sediment prevalence values of E. coli O157:H7 in 10 pens supplied with chlorinated drinking water supplies compared with nonchlorinated water pens. Pulsed-field gel electrophoresis of XbaI-digested bacterial DNA of the 230 isolates obtained from eight of the pens revealed 56 unique restriction endonuclease digestion patterns (REDPs), although nearly 60% of the isolates belonged to a group of four closely related genetic subtypes that were present in each of the pens and throughout the sampling period. The other REDPs were typically transiently detected, often in single pens and on single sample dates, and in many cases were also closely related to the four predominant REDPs. The persistence and predominance of a few REDPs observed over the entire feeding period on this livestock operation highlight the importance of the farm environment, and not necessarily the incoming cattle, as a potential source or reservoir of E. coli O157:H7 on farms.     

The effects of released pheasants on invertebrate populations in and around woodland release sites

The release of gamebirds for recreational shooting exerts a series of effects on the ecosystems into which they are placed. Pheasants (Phasianus colchicus) are omnivorous and eat invertebrates, especially when young or, if females, when breeding. Consequently, the release of large numbers of pheasants into woodland release pens may affect local invertebrate populations. Previous studies have reported mixed evidence. We conducted pitfall trapping at 13 sites (49 pens) in central England over 2 years (totaling 65 pen measures), comprising three surveys annually, immediately prior to releases in mid‐summer, 4 weeks later when most birds were still in the pens, and another 5 weeks later when most birds had dispersed. We compared traps inside and 25 m outside pens in the same wood. We considered release densities and whether the birds had prior experience of eating invertebrates. While accounting for overall seasonal declines in invertebrates trapped, we detected changes for total invertebrate biomass and total counts indicative of released pheasants causing local decreases inside pens, either directly by predation or indirectly by modifying vegetation. There were also relative decreases outside pens when the pheasants start to disperse, suggesting that the released pheasants may be affecting invertebrates in those nearby areas or that their earlier effects inside the pen, modifying vegetation or increasing invertebrate activity, increased the relative susceptibility of invertebrates there to trapping. However, these effects were not seen for specific invertebrate groups believed to be especially susceptible to pheasants. For slugs and detritivores, we detected small population increases inside pens. Across the study period, decreases for most measures were greater outside pens than inside them. We conclude that any effects pheasants have on invertebrate communities at release sites in woodlands are complex and that long‐term and taxon‐specific studies should be considered to understand the local net ecological effects of gamebird releases on invertebrates.     

Handstand Scent Marking in the Dwarf Mongoose (Helogale parvula)

Many mammal species adopt marking postures that elevate their scent deposits. The most extreme of these is handstand marking, in which an individual reverses against an upright object, flings its hind legs into the air above its back and balances bipedally on its fore feet. The resulting anogenital deposit is thus raised one full body length above ground level. It has been suggested that this energetically costly form of marking serves to provide conspecifics with information about the marker's body size and hence competitive ability. However, this explanation assumes that the height of an individuals’ deposit does reflect accurately its body size, an assumption that has never been tested in any hand‐standing species. This study investigated the relationship between body size and handstand mark height in a wild population of dwarf mongooses (Helogale parvula) in South Africa. We found that although body size and marking height were correlated positively for female dwarf mongooses, they were not related for males. Male dwarf mongooses (who are subject to intrasexual competition from outside their group) invested more heavily in anogenital range marking, marking at three times the female frequency and placing their deposits significantly higher than females (although they were not dimorphic). Males that were particularly vulnerable to rivals (i.e. those that were small for their age) tended to mark higher than more robust age‐mates, in keeping with the predictions of Adams & Mesterton‐Gibbons’ (1995, J. Theor. Biol.175, 405–421). model of deceptive threat communication. These findings suggest strongly that the height of anogenital scent deposits is of social significance to dwarf mongooses.     

Effects of predation and habitat structure on the population dynamics of house mice in large outdoor enclosures

This paper examines the effect of different levels of protection from predation on feral house mice. Mice were contained in eight 50×50 m outdoor enclosures. Enclosures allowed access to a suite of freeliving vertebrate predators from the surrounding area, including feral foxes, feral cats and Australian raptors. A 10–15% cover of small, felled cypress pine trees was added in strips to low grassland to increase habitat complexity. Mice were not protected from predation when compared with low grassland pens, possibly because predators were able to focus their hunting activity in the strips. However, when felled trees were covered with wire netting, hence providing higher quality refuge, mouse populations achieved higher densities than in low grassland pens. A predator exclusion treatment was used to confirm the refuge effect was due to a reduction in the impact of predation. Survival rates under the different treatments were generally consistent with population level responses, with mice having lower survival in low grassland pens than in high refuge pens. This is the first study with mammals that confirms the importance of refuges from predators for prey populations.