Population dynamics and food habits of the banded mongoose

A population of approximately 100 banded mongooses living in six packs was studied for over 2 years in Rwenzori National Park, Uganda. The packs were relatively stable, cohesive social units composed of approximately equal numbers of males and females and varied in size from six to thirty-five adults and subadults. Breeding was synchronized within the packs with several females producing their litters at approximately the same time. The packs bred up to four times per year. Mortality of animals over 6 months old was approximately 10% annually. Less than 50% of juveniles survived to the age of 3 months. The banded mongoose feeds primarily on invertebrates, particularly millipedes and beetles. Ants, crickets, termites and earwigs are also important elements of the diet. Vertebrate remains were found in 12% of the droppings analysed. Although the pack forages as a unit each individual finds its own food. The mean home range size of five of the packs was 80-4 ha; the two largest packs had ranges exceeding 1 km². The banded mongoose is strictly diurnal typically leaving a den in the hour following sunrise and returning a few minutes before sunset with a prolonged rest during the heat of the day. Dens were in termite mounds (usually in thicket clumps), erosion gullies, aardvark holes and occasionally in man-made structures. Most were used for only a few days and then abandoned but a few preferred dens were occupied for periods up to 54 days and re-used repeatedly. Interactions between packs were aggressive and appeared to function in spacing the packs. The result of an encounter depended upon pack size with larger packs dominating smaller ones; the area of occurrence did not appear to affect the outcome. Mating between packs was observed during aggressive encounters. Group life is of adaptive significance in protecting the individual from predators and in care of the young. The pack bunches around young mongooses when disturbed and also bunches to attack certain predators and competitors. One or more adults remain at the den to guard the young when the pack forages.     

Dwarf Mongoose Helpers at the Den1

This field study investigated helper behaviour in the care of the young in a small social carnivore, the dwarf mongoose (Helogale parvula). The frequency with which individually marked mongooses, living in six packs, guarded young at the den (babysitting) and brought food to the young was recorded in all-day and morning watches. The principal helpers were the subordinate adult ♀♀ and the yearlings. In a pack of known kinship relationships, an immigrant ♀ did more babysitting than any of the other pack members, all of whom were related to the young. Possible advantages of the aid-giving behaviour to the helpers are discussed.     

Mutual synchronization of diurnal activity rhythms in groups of Red wolf/coyote hybrids

Two packs of Red wolf/coyote hybrids (ancestral species Canis niger and C. latrans) , each consisting of three males and two females, were observed around the clock (a) when the males and females of each pack were housed in separate enclosures, and (b) when the males and females of each pack were reunited. The animals lived in outdoor enclosures under natural lighting conditions, and the period of separation by sex lasted for three months. The activity rhythm was typically bimodal with peaks at dawn and dusk, and total activity was greater during the day than during the night. The activity rhythms of all four single-sex groups differed significantly from one another during the period of separation, but the differences between the sexes within each pack were reduced when the animals were reunited. We conclude that the activity rhythms of the members of each cohabiting group or pack tended to be mutually synchronized by means of social zeitgebers generated within the group. In addition, however, the data suggest that reuniting the sexes resulted in greater uniformity of activity rhythms between the packs, implying that the social structure of the pack may also have altered the responsivity of the members to external zeitgebers (time-setters). Activity budgets showed that about 80% of total time was spent resting or in the den, and about 17% in general locomotion.     

How does parental role influence the activity and movements of breeding wolves?

We studied the activity and movements of a male and a female wolf during breeding in the Bieszczady Mountains, Poland. The female was less active and mobile and on average closer to the den than the male. The male was less active and mobile when the pack size was seven compared to a year when the pack consisted only of the breeding pair. We conclude that the roles played by breeding males and females rearing pups influence their activity, and that breeding males in larger packs move less during the nursing period because of help by other pack members.     

Food,microhabitat, or both? Macroinvertebrate use of leaf accumulations in a montane stream

1. Leaf packs in streams may serve as food and substrate to many macroinvertebrates, but the relative importance of these two functions has not been disentangled. To test the hypothesis that leaf packs are colonized primarily for their food value rather than as microhabitat, the colonization of leaf packs of red alder and of polyester cloth in a natural stream was compared. 2. Species of shredders showed large differences in the colonization of the two types of leaf pack with almost no use of artificial leaf packs. Non-shredders were also more abundant on natural leaf packs, however, they colonized artificial leaf packs six to eighty times proportionally more than shredders. 3. The effect of different leaf types was virtually eliminated for non-shredders when the amount of fine parriculate detritus (food for many non-shredders) trapped in the leaf pack was added to the analysis as a covariate. Therefore, to non-shredders, leaf types differed only in the retention of fine particulate organic matter. 4. Comparisons of the use of both kinds of leaf packs in riffles versus pools revealed that significantly fewer animals colonized pool leaf packs. 5. These results suggest that food value, and not microhabitat, is the primary determinant of leaf pack use for most shredders and non-shredders.     

Development of a bait and baiting system for delivery of oral rabies vaccine to free-ranging African wild dogs (Lycaon pictus)

The objective of the study was to develop a bait and baiting system capable of delivering one effective dose of oral rabies vaccine to each member of a free-ranging African wild dog (Lycaon pictus) pack. Trials were conducted between June and October 2000. The results of cafeteria-style bait preference trials testing seven candidate baits in captive wild dogs revealed a significant preference for chicken heads (June trials: P = 0.023, September trials: P = 0.021). Trials using a topical biomarker (rhodamine B) showed that chicken head baits were sufficiently chewed on most occasions to rupture the vaccine container. Free-ranging wild dogs and young pups ingested chicken head baits. Significant dominance of bait intake by a single individual was seen in four of six study packs and in the three packs in which an alpha pair could be distinguished, the dominant feeder was an alpha animal. Pattern of bait distribution and degree of satiation had no effect on pack coverage (proportion of pack ingesting at least one bait). Pack coverage was significantly related to trial number (r = 0.71, P < 0.001), with pack coverage increasing with increased exposure of the pack to the baits. During 46 hr of diurnal observations of free-ranging wild dogs only two baits were lost to non-target species. A baiting system for the oral vaccination of captive and free-ranging wild dogs is proposed.     

Resource Utilization and Temporal Segregation of Scarabaeinae (Coleoptera,Scarabaeidae) Community in a Caatinga Fragment

We characterized dung beetles food preference and diel activity and examined the way such characteristics may structure a Scarabaeinae community in a dry forest. We sampled a fragment of Arboreal Caatinga in Milagres, Bahia, Brazil, during the dry and wet seasons, using baited pitfall (bovine spleen, human feces, cow dung, and rotten banana). Species were classified by activity (nocturnal and diurnal) and food preference (coprophagous, necrophagous, saprophagous, copro-necrophagous, and generalist). In total, 1,581 individuals belonging to 16 morphospecies were sampled, with six new records for Caatinga. The dung beetles were mainly from generalist and coprophagous species; seven species presented nocturnal activity, and five were diurnal. There was higher species richness during the day and greater abundance during the night. Species composition differences were influenced by functional guilds and beetle size according to temporal segregation. These factors may be related to physiological, morphological, and behavioral differences.     

Behavioral Ecology of Coyotes: Social Organization,Rearing Patterns,Space Use,and Resource Defense

Two groups of coyotes in which genealogical relationships were known were studied in the Grand Teton National Park, outside of Jackson, Wyoming, U.S.A., from 1977–1982. One group, a pack consisting of parents and some non-dispersing and non-breeding offspring, defended a territory and the food (mainly elk carrion) contained within it, especially during winter, and also had helpers at den sites (5 of 6 were males). The other group, a mated resident pair, all of whose young dispersed during the first year of life, did not defend a territory and never had helpers at dens. Delayed dispersal and retention of some offspring as helpers was related to the presence of an abundant, clumped, and defendable winter food resource. Dispersing yearlings suffered higher mortality than did non-dispersing individuals. Litter size was the same for the pack and resident pair; litter size was not significantly correlated with number of adults in the group or with the number or percentage of pups that survived to 5–6 months of age. The presence of pack helpers was not significantly correlated with pup survival, although there was a positive correlation (r^s = +0.37) between the number of adults attending a den(s) and pup survival. Helpers rarely fed pups and their presence had no appreciable effect on juvenile weight. Helpers partook in den-sitting (pup-guarding), but they did not reduce the amount of time that parents spent at den sites. Helpers also actively initiated and took part in territorial and food defense. The proportion of times that pack members initiated defense was inversely related to intruder density (r = –0.94).     

THE SOCIABLE WEAVER,PART 5: FOOD,FEEDING AND GENERAL BEHAVIOUR

Maclean, G. L. 1973. The Sociable Weaver, Part 5: Food, feeding and general behaviour. Ostrich 44:254-261.

The food of the Sociable Weaver during the study period consisted of 78,9% animal material by weight; the rest was mainly seeds, mostly of green grasses. The young are fed entirely on animal food. The most important single source of animal food in the Kalahari is the harvester termite Hodotermes mossambica. Sociable Weavers are independent of drinking water under natural conditions. Members of a colony do not usually feed more than about 1,5 km from the nest mass.

Maintenance activities and other general behaviour patterns of the Sociable Weaver are described; they are typically passerine.     

Diel periodicity in the behaviour of the caddisfly, Brachycentrus americanus (Banks)

Behaviour of Brachycentrus americanus was observed in a simulated stream in the laboratory every 2 h for 7 days in January, and in Lawrence Creek, Wisconsin, every half hour for 2 days in May. In the field, animals, algae, and detritus in the drift were sampled every half hour with an 800-μm and a 60-μm mesh net. The primary mutually-exclusive behavioural units were filtering, case building, and withdrawn when the larvae had their cases attached to the substrate, and crawling and holding when cases were not attached. Diel changes in behaviour were similar i n the laboratory and field. Almost 100% of the animals were filtering at night, whereas only about 60% were during day. Withdrawn, case building and unattached activities occurred more frequently during the day. While only 0-5% of the laboratory animals were unattached during the day, in Lawrence Creek 10-20% were unattached at that time and many moved across the substrate and grazed. Drifting, which was acyclic, did not correlate closely with the diurnal increase in unattached activity. Available drifting food in both nets increased markedly following rain. In the absence of rain, dry weight of detritus from the 800-μm net increased at night. Changes i n timing and method of feeding are discussed relative to gut contents, morphological adaptations, and energy expenditure of B. americanus, and to food availability.     

Male-biased Adult Sex Ratios and their Significance for Cooperative Breeding in Dhole,Cuon alpinus,Packs

Two free-ranging packs of dholes (Asiatic wild dog, Cuon alpinus) were monitored for a period of 6 yr (Sep. 1990-Sep. 1996) in the Mudumalai sanctuary, southern India. Demographic data on age structure, litter-size, sex ratio and age and sex specific dispersal were collected. Behavioural data on social interactions and reproductive behaviour among pack members were obtained to determine the frequencies of dominant and subordinate behaviours shown by male and female pack members and a measure of each male's reproductive access to females. Behaviours displayed by pack members at dens were recorded to determine whether any age- or sex-specific role specialization existed during pup care. Tenures for dominant males and females within the pack were calculated to ascertain the rate of breeding vacancies occurring within packs. Approximate levels of genetic relatedness within packs were determined by studying pedigrees. In most years one study pack had a male-biased adult sex ratio. This was caused by almost two-fold higher dispersal of adult females over adult males. A considerable variance existed in the percentage of sub-adults dispersing from the two packs. Differences existed in the frequencies of dominant and subordinate behaviours shown by males. For males, dominance ranks and ranks based on submissive behaviours were not correlated with frequencies of reproductive behaviours. Subordinate males also displayed reproductive behaviours. In packs, dominant males had lower tenures than dominant females indicating that among males breeding vacancies arose more quickly. The litter size was found to be negatively correlated with the age of the breeding female. There were no significant differences across individuals of varying age or sex classes in the display of pup care behaviours. Significant differences did exist among individual adults. Genetic relatedness among packs tended to vary temporally as a consequence of possible mating by subordinate animals and immigration of new males into the pack. In conclusion, it appears that males delay dispersal and cooperate within their natal packs because of the variety of reproductive strategies they could pursue within. A combination of ecological constraints and the difficulties of achieving breeding status within non-natal packs may make early dispersal and independent breeding less beneficial.     

Movements and habitat use in gravid and nongravid female garter snakes (Colubridae: Thamnophis)

Two dhole ( Cuon alpinus ) packs were monitored in Mudumalai Sanctuary, southern India, during 1989-93 to look at population dynamics, movement pattern, and foraging strategy and their inter-relationship with the maintenance of social groups. Pack size fluctuated substantially (4–18 and 4–25 in the two packs) owing to dispersal and demographic factors such as females not breeding in a given year. Both packs killed a much higher proportion of chital ( Axis axis ) and sambar ( Cervus unicolor ) fawns (2 and 54.2km² for the two packs) was not correlated with pack size. Pack movement from one resource patch (consisting of resting sites and aggregations of prey species) to another was not random or based on factors such as inter-patch distance or relative prey densities. There was no difference in mean residence time of the pack across the four resource patches; the pack moved across these in a sequential manner in one direction. We conclude that dholes live in groups not because of any advantages accruing from enhanced group sizes through increased per capita yield of food, but as a consequence of the dispersion of resources.     

Field implantation of intraperitoneal radiotransmitters in Eastern Wolf (Canis lycaon ) pups using inhalation anesthesia with sevoflurane

In a study of wolf pup survival, intraperitoneal radio transmitters were surgically implanted in 53 (27 male and 26 female) 3.5- to 8-wk-old Eastern wolf (Canis lycaon) pups at den sites in Algonquin Provincial Park, Ontario, Canada, over two whelping seasons (2004 and 2005). Pups were manually removed from dens and initially injected with butorphanol at a dosage of 0.1 mg/kg for sedation and intra-operative analgesia. Anesthesia was induced and maintained with 3% sevoflurane in oxygen via a face mask. Meloxicam (0.3 mg/kg intramuscularly) was given to provide additional analgesia. All surgeries were completed without complications, and pups were readily accepted back into the packs. No postoperative complications were identified, but two pups from a single litter drowned as a result of being moved by the pack to a flooded den following the surgery. In five pups necropsied following natural deaths, transmitters were found lying free within the peritoneal cavity, and there was no evidence of infection at the surgical site or peritonitis. Inhalation anesthesia provided extremely rapid induction (1 min) and recovery (<3 min) and was completely controllable with no residual anesthetic effects. The equipment for inhalation anesthesia was readily portable in field packs, and it has considerable advantages over injectable drugs for small and very young animals such as wolf pups. The utility of the procedure is demonstrated by the minimal effect it had on subsequent pup survival, the rapid recovery of pups following surgery, and the lack of long-term complications as determined by necropsies of pups following natural deaths.     

Two distinct poly(A) polymerases in yeast nuclei

β-Hydroxy-β-methylglutaryl coenzyme A reductase activity in rat liver increased 2 to 7-fold after subcutaneous administration of insulin into normal or diabetic animals. Reductase activity began increasing after one hour, rose to a maximum in two to three hours, and then declined to the control level after six hours. This response was elicited during the time of day when the normal diurnal variation in reductase activity approached a minimum. It was also elicited when animals did not have access to food. This stimulation of reductase activity was completely blocked when glucagon was administered in conjunction with insulin. The increase in reductase activity after insulin administration was accompanied by a proportionate increase in activity for the conversion of acetate to cholesterol.     

Community responses to experimental food depletion: resource tracking by stream invertebrates

The regulation of population processes for most organisms depends upon the strength and rate of feedback between resources and consumers. We conducted an experimental manipulation of leaf packs in stream channels, a patchy and ephemeral resource, which is consumed by a number of detritivorous invertebrates. We reduced the number of available food patches (red alder leaf packs) by half and then measured a variety of community responses, including emigration rate, aggregation on remaining food patches, decomposition rate of food patches, and species-specific differences in these responses. Replacement of removed leaf packs with polyester mimics resulted in no statistical difference in emigration rates or aggregation on remaining resources when compared to those removal channels without replacement. These results indicate that leaf packs are not used primarily for refuge. In the removal channels (including those with leaf pack mimics) emigration rate nearly doubled relative to control channels. Those invertebrates that did not emigrate from removal channels aggregated on remaining leaf packs, which led to more rapid decomposition of leaf packs relative to control channels. The increase in emigration rate only became apparent 2-3 days after the manipulation, presumably because animals colonized the remaining leaf packs and did not emigrate until food patch value per individual had been reduced by higher densities or due to increased discharge. Discharge through the channels increased slightly starting 3 days after the manipulation, resulting in increased emigration rates in all channels. Despite the increase in discharge, the effect of the manipulation remained strong. These results show that stream invertebrates colonizing leaf packs responded in predictable ways to a short-term reduction in food resources which would be adaptive in a system which is heterogeneous in space and time.     

Urinary melatonin rhythms during sleep deprivation in depressed patients and normals

Melatonin excretion was measured in 8 hour urine aliquots for eight healthy controls and six depressed patients. Both groups had similar diurnal rhythms, with increased melatonin excretion during the night. When subjects were sleep deprived, remaining awake and active in continuous light from 7 a.m. one morning until 11 p.m. the following day, the diurnal rhythm in melatonin excretion remained unchanged. These data in man appear to be inconsistent with previous studies in rats showing rapid light-induced suppression of the nocturnal rise in pineal melatonin synthesis.     

The finely defined shift work schedule of dung beetles and their eye morphology

In nature, nothing is wasted, not even waste. Dung, composed of metabolic trash and leftovers of food, is a high‐quality resource and the object of fierce competition. Over 800 dung beetle species (Scarabaeinae) compete in the South African dung habitat and more than 100 species can colonize a single dung pat. To coexist in the same space, using the same food, beetles divide the day between them. However, detailed diel activity periods and associated morphological adaptations have been largely overlooked in these dung‐loving insects. To address this, we used a high‐frequency trapping design to establish the diel activity period of 44 dung beetle species in their South Africa communities. This allowed us to conclude that the dung beetles show a highly refined temporal partitioning strategy, with differences in peak of activity even within the diurnal, crepuscular, and nocturnal guilds, independent of nesting behavior and taxonomic classification. We further analyzed differences in eye and body size of our 44 model species and describe their variability in external eye morphology. In general, nocturnal species are bigger than crepuscular and diurnal species, and as expected, the absolute and relative eye size is greatest in nocturnal species, followed by crepuscular and then diurnal species. A more surprising finding was that corneal structure (smooth or facetted) is influenced by the activity period of the species, appearing flat in the nocturnal species and highly curved in the diurnal species. The role of the canthus—a cuticular structure that partially or completely divides the dung beetle eye into dorsal and ventral parts—remains a mystery, but the large number of species investigated in this study nevertheless allowed us to reject any correlation between its presence and the nesting behavior or time of activity of the beetles.     

Over-winter decomposition and associated macroinvertebrate communities of three deciduous leaf species in forest streams on the Canadian Boreal Shield

The decomposition of deciduous leaf material provides a critical source of energy to aquatic food webs. Changes to riparian forests through harvesting practices may alter the species composition of deciduous leaf material entering streams. We compared over-winter decomposition of three different riparian leaf species (speckled alder (Alnus incana ssp. rugosa (Du Roi) J. Clausen), white birch (Betula papyrifera Marsh.), and trembling aspen (Populus tremuloides Michx.)) to determine their importance as a food resource for macroinvertebrate communities within Boreal Shield streams in northeastern Ontario, Canada. Leaf pack decomposition of the three leaf species formed a processing continuum throughout winter, where alder and birch leaf packs decomposed at a medium rate (k = 0.0065/day and 0.0053/day, respectively) and aspen leaf packs decomposed more slowly (k = 0.0035/day). Macroinvertebrate community colonization on leaf packs changed through time regardless of leaf species. Alder leaf packs supported higher abundances of macroinvertebrates in the fall while aspen leaf packs supported greater shredder abundances in the following spring. The study shows that leaf diversity may be important for providing a sustained food resource for aquatic macroinvertebrates throughout the relatively long over-winter period in Canadian Boreal Shield streams. Riparian forest management strategies should ensure that deciduous plant species richness is sustained in riparian areas.     

Movements and Home Sites of Timber Wolves in Algonquin Park

Ecological studies of timber wolves (Canis lupus) in a forestedenvironment have always been difficult to undertake in the past,particularly during the summer months, because of the lack ofa suitable technique. In 1960 Pimlott devised a technique whichemployed the use of broadcast wolf howls in locating wolvesin the field. This report reviews the success of this techniquein studying the movements of two packs of wolves, and theiruse of home sites in Algonquin Park, Ontario. Wolves responded by howling a total of 476 occasions or approximately13% of the occasions that broadcast howls were given. Humanimitations were more successful than tape-recordings in inducingresponses. Wolves responded at any time of day, but dusk wasthe most favorable period. They also responded more frequentlyin July and August than in May and June. Two types of home sites were found: the den site, occupied duringthe early life of the pups, and the rendezvous site, a placeoccupied by wolves during later development of pups. All ofhe home sites were adjacent to some immediate source of water.The movement of wolves appeared also to be concentrated alongthe water courses. The locations of the home sites and the evidence obtained fromhowling responses, tracks, and scats suggested that the summerrange comprised a minimum area of eight square miles. The samerange was utilized by a pack in 1961 and 1963.     

Annelid sperm and fertilization biology

This paper provides data on fine particulate organic matter (FPOM) and macroinvertebrates associated to natural and artificial leaf packs in a small woodland stream (Schlaube, Brandenburg). Macroinvertebrate colonisation and the dynamics of FPOM were studied in oven-dried alder leaf packs, air-dried alder leaf packs and packs with artificial leafshaped substrate exposed in the stream during a 68-day period. The importance of FPOM as a potential food source for macroinvertebrates especially in artificial leaf packs was evaluated. Changes in the quantity as well as in the chemical composition of the accumulating FPOM (>63 and <63 μm) was determined using soluble carbohydrates, proteins and chlorophyll a as parameters of the nutritional quality. Mass loss and the chemical changes of alder leaves during the decompositional process were also described. The loss of soluble carbohydrates due to leaching was more rapid in oven-dried alder leaf packs than in air-dried ones. After 3 days of leaf pack exposure weight loss of oven-dried and air-dried leaf packs was nearly comparable, as the similar decay coefficients, k = 0.0228 (oven-dried leaf packs) and k = 0.0214 (air-dried leaf packs), respectively, show. The amount of FPOM per unit leaf area constantly increased in artificial packs, although it remained below that of alder leaf packs at all sampling dates. The nutritional quality of FPOM <63 μm was constantly greater than that of FPOM >63 μm and decreased in both size-fractions with length of exposure. Referring to leaf area the abundance of macroinvertebrates continually increased in all packs till the end of exposure, whereas the numbers in artificial packs remained below that in alder leaf packs. The taxonomic composition of all treatments was very similar with Gammarus pulex being the most abundant taxon in all packs until day 42, while afterwards the caddis fly genus Hydropsyche gained in importance. The amphipod Gammarus pulex in general did not show a preference for air-dried alder leaf packs compared to oven-dried alder leaf and artificial packs. Corresponding dynamics of macroinvertebrate colonisation and FPOM content in artificial packs support the hypothesis that FPOM functions not only as an important food source for macroinvertebrates including gammarideans but also as a control mechanism of macroinvertebrate abundance in stream habitats. Even if the accumulation of FPOM and drifting macroinvertebrates might be influenced by the same abiotic factor (e.g. by reduction in stream velocity inside the packs) it is quite unlikely that only physical properties caused the invertebrates to stay.