Intra- and intraspecific variation of Juniperus virginiana and J. scopulorum seedling based on volatile oil composition

Comparisons of volatile oil constituents were made among samples of juvenile foliage collected from 78 Juniperus virginiana and 28 J. scopulorum seedling sources growing in a “common garden” environment. A canonical variate analysis, a principal coordinates analysis and hybrid distance diagrams of 30 chemical characters indicate both taxa are good species and that they exhibit clinical patterns in the Great Plains. In addition, a possible evoluitonary link between present-day J. virginiana populations in southern Texas and ancient J. scopulorum populations is indicated.     

Conversion of Japanese red cedar (Cryptomeria japonica) into a feed for ruminants by white-rot basidiomycetes

The potential of five white-rot fungi to convert Japanese red cedar (Cryptomeria japonica) into feed for ruminants was determined. Pleurotus ostreatus (ATCC 66376), Pholiota nameko (IFO 30373), Dichomitus squalens (CBS 432.34), Lentinula edodes (IFO 6654) and Ceriporiopsis subvermispora (ATCC 90467) were inoculated into chips of cedar sapwood. L. edodes was cultured at 25 °C, and the other fungi at 28 °C, for 4, 8, 12, or 20 weeks. The in vitro organic matter (OM) digestibility (IVOMD) in cedar wood cultured without fungus were between 0.047 and 0.068, while it was elevated to 0.446 by culturing with C. subvermispora and to 0.281 by culturing with L. edodes for 20 weeks. In contrast, the IVOMD were 0.200, or lower, in cedar wood cultured with P. ostreatus, P. nameko, or D. squalens. The in vitro gas production (IVGP) in cedar wood cultured with P. ostreatus, P. nameko, or D. squalens was 37 ml/g OM, or lower, while that in cedar not inoculated with fungus was between 4 and 17 ml/g OM. In contrast, the IVGP in cedar wood cultured with C. subvermispora for 20 weeks increased to 107 ml/g OM, and that in cedar wood cultured with L. edodes increased to 58 ml/g OM. Lignin degradability in cedar wood cultured with C. subvermispora and L. edodes for 20 weeks were 0.578 and 0.288, respectively. These changes in IVOMD and IVGP demonstrate that a selective white-rot fungus, C. subvermispora has the ability to convert cedar wood into feed for ruminants, although further increase is required before the cultured cedar wood would have widespread feed potential.     

Morphological variation of Juniperus oxycedrus subsp. oxycedrus (Cupressaceae) in the Mediterranean region

The intra- and inter-population variation of Juniperus oxycedrus subsp. oxycedrus were examined biometrically on the basis of morphological characters of needles, seeds and cones. Cluster analysis of Euclidean distances and discriminant analysis were performed to verify the hypothesis of geographic differentiation and origin from the West- and East-Mediterranean Pleistocene refugial regions. The West-Mediterranean populations of J. oxycedrus subsp. oxycedrus differed from the eastern ones. The intra-populational differentiation of three of the West-Mediterranean populations was significantly higher than within the other West- and all the East-Mediterranean ones.Results confirm the hypothesis of probable different origins of the East- and West-Mediterranean populations of the taxon.     

Genetically different isolates of Trypanosoma cruzi elicit different infection dynamics in raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana)

Trypanosoma cruzi is a genetically and biologically diverse species. In the current study we determined T. cruzi infection dynamics in two common North American reservoirs, Virginia opossums (Didelphis virginiana) and raccoons (Procyon lotor). Based on previous molecular and culture data from naturally-exposed animals, we hypothesised that raccoons would have a longer patent period than opossums, and raccoons would be competent reservoirs for both genotypes T. cruzi I (TcI) and TcIIa, while opossums would only serve as hosts for TcI. Individuals (n = 2 or 3) of each species were inoculated with 1 × 10⁶ culture-derived T. cruzi trypomastigotes of TcIIa (North American (NA) – raccoon), TcI (NA – opossum), TcIIb (South American – human), or both TcI and TcIIa. Parasitemias in opossums gradually increased and declined rapidly, whereas parasitemias peaked sooner in raccoons and they maintained relatively high parasitemia for 5 weeks. Raccoons became infected with all three T. cruzi strains, while opossums only became infected with TcI and TcIIb. Although opossums were susceptible to TcIIb, infection dynamics were dramatically different compared with TcI. Opossums inoculated with TcIIb seroconverted, but parasitemia duration was short and only detectable by PCR. In addition, raccoons seroconverted sooner (3–7 days post inoculation) than opossums (10 days post inoculation). These data suggest that infection dynamics of various T. cruzi strains can differ considerably in different wildlife hosts.     

Isoenzyme diversity and cryptic speciation in Juniperus excelsa (Cupressaceae) complex in Iran

An isoenzyme analysis was performed on 109 individuals from 11 populations of Juniperus excelsa complex collected from Iran. A total of 61 allozymes from five enzyme systems were scored. The mean numbers of bands per presumed isoenzyme, ranged from 2.07 to 3.23. The value of Euclidean distance ranged from 1.920 to 4.411. The average value of Shannon diversity index (H′) estimated for each population ranged from 0.317 in the population sampled from ‘Fasa’ to 1.053 in the population of ‘Golestan’, and the average H′ value for each enzyme system ranged from 0.031 (SOD-3) to 1.670 (PPO-1). To reveal the relationships among these populations, a cluster analysis based on Euclidean distances was performed. The results of the analysis suggest recognizing three taxa in the complex in Iran: Juniperus polycarpos subsp. polycarpos, Juniperus polycarpos subsp. turcomanica, and one cryptic species not recorded from Iran until now. Moreover, the analysis presented, does not confirm the occurrence of J. excelsa in Iran.     

The effects of mate removal on pregnancy success in prairie voles (Microtus ochrogaster) and meadow voles (Microtus pennsylvanicus).

The effects of removing the stud male have not been controlled in many studies relating pregnancy block to the presence of an unfamiliar male. We examined the effects of removing the male on pregnancy success in prairie voles and meadow voles, two species that differ in degree of paternal investment. Whereas prairie vole males provide extensive care to offspring and accelerate pup development, meadow vole males display little or no care and delay development of pups. We predicted that removal of the stud male would decrease pregnancy success in prairie voles and either have no effect or increase success in meadow voles. In experiment 1, females were in male-induced estrus, and their mates were either left with them or were removed 4 h, 1 day, 2 days, or 8 days after mating. In experiment 2, females were in postpartum estrus, and their mates were either left with them or were removed 1 day, 2 days, or 8 days after birth of their first litter. Removal of the male soon after mating in postpartum estrus decreased pregnancy success in prairie voles and increased success in meadow voles. Thus, although removal of the stud male influenced litter production, the direction of the effect varied with species.     

Nutrient removal by thermophilic Fischerella (Mastigocladus laminosus) in a simulated algaculture process

A novel nutrient removal/waste heat utilization process was simulated using semicontinuous cultures of the thermophilic cyanobacterium Fischerella. Dissolved inorganic carbon (DIC)-enriched cultures, maintained with 10 mg l⁻¹ daily productivity, diurnally varying temperature (from 55°C to 26–28°C), a 12:12 light cycle (200 μE sec⁻¹ m⁻²) and 50% biomass recycling into heated effluent at the beginning of each light period, removed > 95% of NO₃⁻ + NO₂⁻−N, 71% of NH₃-N, 82% of PO₄³⁻ −P, and 70% of total P from effluent water samples containing approximately 400 μg l⁻¹ combined N and 60 μg l⁻¹ P. Nutrient removal was not severely impaired by an altered temperature gradient, doubled light intensity, or DIC limitation. Recycling 75% of the biomass at the end of each light period resulted in unimpaired NO₃⁻ + NO₂⁻ removal, 38–45% P removal and no net NH₃ removal. Diurnally varying P removal, averaging 50–60%, and nearly constant > 80% N removal, are therefore projected for a full-scale process with continuous biomass recycling.     

Ecophysiological responses of salt cedar (Tamarix spp. L.) to the northern tamarisk beetle (Diorhabdacarinulata Desbrochers) in a controlled environment

The northern tamarisk beetle (Diorhabda carinulata Desbrochers) was released in several western states as a biocontrol agent to suppress Tamarix spp. L. which has invaded riparian ecosystems; however, effects of beetle herbivory on Tamarix physiology are largely undocumented and may have ecosystem ramifications. Herbivory by this insect produces discoloration of leaves and premature leaf drop in these ecosystems, yet the cause of premature leaf drop and the effects of this leaf drop are still unknown. Insect herbivory may change leaf photosynthesis and respiration and may affect a plant’s ability to regulate water loss and increase water stress. Premature leaf drop may affect plant tissue chemistry and belowground carbon allocation. We conducted a greenhouse experiment to understand how Tamarix responds physiologically to adult beetle and larvae herbivory and to determine the proximate cause of premature leaf drop. We hypothesized that plants experiencing beetle herbivory would have greater leaf and root respiration rates, greater photosynthesis, increased water stress, inefficient leaf nitrogen retranslocation, lower root biomass and lower total non-structural carbohydrates in roots. Insect herbivory reduced photosynthesis rates, minimally affected respiration rates, but significantly increased water loss during daytime and nighttime hours and this produced increased water stress. The proximate cause for premature leaf drop appears to be desiccation. Plants exposed to herbivory were inefficient in their retranslocation of nitrogen before premature leaf drop. Root biomass showed a decreasing trend in plants subjected to herbivory. Stress induced by herbivory may render these trees less competitive in future growing seasons.     

Diets of prairie dogs (Cynomys mexicanus) co-existing with cattle or goats

Diets of prairie dogs (Cynomys mexicanus) co-existing with goats or cattle were examined using microhistological fecal analysis in a 1-year study on a grassland of northern Mexico. Consumption of forbs was generally higher (33% versus 21% across all seasons; P< 0.05) in prairie dog diets co-existing with cattle compared to prairie dogs co-existing with goats. The diet of prairie dogs grazing with goats was based around grasses (79% of total forage ingested versus 68% for prairie dogs on the pasture grazed by cattle all seasons; P<0.05). In general, prairie dogs showed a higher preference for forbs in the pasture grazed by cattle than in the pasture grazed by goats. Data for dietary overlap (69% across all seasons) pointed to a moderate diet similarity between prairie dogs grazing with goats or cattle. Prairie dogs co-existing with goats had a higher (P<0.05) fecal N concentration in the fall than prairie dog co-occurring with cattle (2.4±0.1 versus 2.1±0.1). In spring and summer, prairie dogs in the pasture shared with goats had higher (P<0.05) fecal P concentrations than prairie dog co-existing with cattle (3.0±0.4 versus 2.5±0.2 and 1.6±0.1 versus 1.0±0.1, respectively). The results of this study indicate distinct differences in diets of prairie dogs co-existing with goats or cattle, although these foraging differences did not affect negatively the diet quality of prairie dogs (based on fecal N and P data) grazing with goats, despite the highly degraded range in this site. Prairie dogs showed a high feeding adaptability, which allowed them to meet their nutritional needs in a highly degraded site around the goat's pens in a settlement with communal grazing land.     

Impacts of simulated livestock grazing on Utah prairie dogs (Cynomys parvidens) in a low productivity ecosystem

Allometric foraging theory suggests that herbivores of greatly differing size should co-exist through niche segregation, but a few studies of large–small herbivore foraging relationships have reported competitive interactions. This study addresses the potential roles of habitat productivity and large herbivore grazing intensities on large–small herbivore foraging interactions. We examined effects of different intensity simulated grazing treatments on forage abundance and quality for Utah prairie dogs (Cynomys parvidens) in a low productivity ecosystem, and consequent effects on prairie dog individual growth rates, foraging preferences, and activity budgets. We hypothesized that simulated grazing would have predominantly facilitative impacts on Utah prairie dogs, as was found for black-tailed prairie dogs in higher productivity ecosystems. To test this hypothesis, we measured the effects of simulated grazing on forage nitrogen, digestibility, and biomass. Simulated grazing increased average forage nitrogen and digestibility while decreasing forage biomass. These effects were associated with reduced individual growth rates, increased juvenile foraging time, and reduced juvenile vigilance. Results suggest that the negative effects of reduced vegetation biomass greatly outweighed positive treatment effects in this study. However, prairie dogs in the moderate intensity defoliation treatment showed some preference for “grazed” plots over “ungrazed” plots, and this preference increased with time. Our study lends support to the idea that habitat productivity and herbivore densities may mediate shifts between facilitative and competitive interactions between different-sized herbivores.     

In vitro cytogenetic effects of Andrographis paniculata (kalmegh) on arsenic

In vitro effects of arsenic in human peripheral lymphocytes (HPL) at three different doses – 3.6×10⁻⁴, 1.4×10⁻³ and 0.72×10⁻³ μM for 24 h before harvesting on sister chromatid exchanges (SCE), Cell cycle proliferative index/replicative index (CCPI/RI), %M₁, %M₂ and %M₃, population doubling time (PDT) and average generation time (AGT) were examined. Andrographis paniculata (commonly referred to as ‘kalmegh’) has been used for centuries in traditional Indian and Chinese herbal medicine as a safe, natural folk remedy for assorted health concerns. In the present study, kalmegh (0.01 μg/7 ml culture media) was used along with the highest dose of arsenic; the results showed that arsenic induced increase in these genotoxic endpoints were fairly diminished by kalmegh. In addition, mutagenic in vitro effect of ethyl methanesulphonate (EMS) was used as a positive control in this study. It is thus concluded from this study that Andrographis has a protective role in arsenic toxicity.     

Grazing on toxic Alexandrium fundyense resting cysts and vegetative cells by the eastern oyster (Crassostrea virginica)

In laboratory experiments, oysters (Crassostrea virginica) were fed Alexandrium fundyense (strain CB501) vegetative cells or resting cysts (from strains CB501 and GMT25) produced from laboratory cultures. The toxicity per cyst was 1.7 pg STXequiv/cyst and for vegetative cells 3.9 pg STXequiv/cell. The toxic, resting cysts and vegetative cells were removed from suspension in the experimental containers within about 4 h. Oysters fed toxic vegetative cells digested 72% of cells ingested, and 28% survived gut passage by forming temporary cysts. Toxin levels of oysters fed vegetative cells averaged 27 μg STXequiv/100 g meat. Resting cysts added to the experimental containers adhered to the walls so that only 40% of the cysts added were available to the oysters during the experiment. Of the cysts that were ingested, approximately 59% were digested, and oysters accumulated toxins (an average of 1.2 μg STXequiv/100 g meat), showing that consumption of resting cysts can cause toxicity in oysters. Direct consumption of resting cysts, thus, may explain shellfish toxicity in areas without known blooms, but with toxic resting cysts in the sediment. These results suggest a possible role of toxic cysts in mediating time-lags between surface blooms and appearance of toxicity in benthic grazers, and the possible role of benthic grazers in controlling seed populations, except in anoxic areas, which can serve as cyst “refuges” from grazing mortality.     

The effects of 2-bromopalmitate on the fatty acid composition in differentiating adipocytes of red sea bream (Pagrus major)

To determine whether external factors affect the adipogenic function of fish adipocytes, the effects of 2-bromopalmitate (a PPAR agonist) on the fatty acid composition in differentiating adipocytes of red sea bream were investigated in vitro. In the presence of 2-bromopalmitate, the red sea bream adipocytes were differentiated and the effects on the fatty acid composition and the adipogenic gene expression were analyzed. With the level of 2-bromopalmitate, the content of 16:1n-7, a delta-9 desaturation product, increased in association with the increase in a stearoyl CoA desaturase (SCD) gene expression level while the triglyceride accumulation was not affected. Subsequently, the effects on the bioconversion of the n-3 and n-6 fatty acids, which are main series of dietary essential fatty acids, were examined. In the presence of 300 μM of 18:3n-3 or 18:2n-6, red sea bream stromal-vascular cells accumulated the lipid in the cytoplasm within 3 days by the fatty acid uptake with the increase of corresponding fatty acid contents. Furthermore, in both the 18:3n-3 and 18:2n-6 stored cells, the products of delta-6 desaturation (18:4n-3 and 18:3n-6, respectively) and C_18–20 elongation (20:3n-3 and 20:2n-6, respectively) were detected. However, neither the delta-6 desatutration nor C_18–20 elongation of 18:3n-3 and 18:2n-6 were enhanced by 2-bromopalmitate treatment. In conclusion, the results indicate that the adipocyte function in fish, e.g. adipogenic gene expression and fatty acid composition, can be modified by external factors and a main effect of 2-bromopalmitate is the increase in the content of delta-9 desaturation product by stimulating the SCD gene expression.     

Diet and physiological responses of Spondyliosoma cantharus (Linnaeus, 1758) to the Caulerpa racemosa var. cylindracea invasion

Marine invasions are a worldwide problem that involves changes in communities and the acclimation of organisms to them. The invasive Chlorophyte Caulerpa racemosa var. cylindracea is widespread in the Mediterranean and colonises large areas from 0 to 70 m in depth. The omnivorous fish Spondyliosoma cantharus presents a high frequency of occurrence of C. racemosa in the stomach contents at invaded areas (76.3%) while no presence of C. racemosa was detected in control areas. The isotopic composition of muscle differed significantly between invaded and non-invaded sites for δ¹³C (− 16.67‰ ± 0.09 and − 17.67‰ ± 0.08, respectively), δ¹⁵N (10.22‰ ± 0.22 and 9.32‰ ± 0.18, respectively) and the C:N ratio (2.01 ± 0.0002 and 1.96 ± 0.009, respectively). Despite the high frequency of occurrence of C. racemosa in the stomach contents of S. cantharus and its important contribution to the δ¹³C source (20.7% ± 16.2), the contribution of C. racemosa to the δ¹⁵N in S. cantharus food sources was very low (6.6% ± 5.8). Other invertebrate prey such as decapods and polychaetes were more important contributors to the δ¹⁵N source at both invaded and non-invaded sites. Activation of enzymatic pathways (catalase, superoxide dismutase, glutathione-s-tranferase, 7-ethoxy resorufin O-de-ethylase) but not a significant increase in lipid peroxidation MDA (0.49 ± 0.01 nmol/mg prot at non-invaded and 0.53 ± 0.01 nmol/mg prot at invaded sites) was observed in S. cantharus individuals living in C. racemosa-invaded sites compared with control specimens. The low δ¹⁵N contribution values of C. racemosa by S. cantharus together with the toxicity demonstrated by the activation of the antioxidant defences and the important contribution of invertebrate prey to the δ¹⁵N could mean that the ingestion of C. racemosa by S. cantharus might be unintentional during the predation of invertebrate preys living underneath the entanglement of the C. racemosa fronds and stolons mats.     

The distribution and abundance of Lernaeocera lusci (Copepoda) on hake (Merluccius merluccius) and bid (Trisopterus luscus) (Teleostei)

Distribution patterns, mean intensity and prevalence of Lernaeocera lusci (Copepoda, Pennellidae) in its 2 hosts Trisopterus luscus (Teleostei, Gadidae) and Merluccius merluccius (Teleostei, Merlucciidae) were examined, together with parasitic abundance and aggregation in relation to the size of the host. The mean parasite abundance and the variance to mean abundance ratio increased with host size, suggesting that the accumulation of this parasite had no noticeable impact on the structure of either host population. Merluccius merluccius being a newly colonized host in the Mediterranean, these results are discussed in relation to current ideas on the evolution of pathogenicity in heterospecific associations.     

Efficacy and environmental fate of Chondrostereum purpureum used as a biological control for red alder (Alnus rubra)

A field trial to assess the ability of Chondrostereum purpureum to limit the resprouting of cut red alder (Alnus rubra) was established in British Columbia, Canada. Overall, 92% of stumps inoculated with C. purpureum died in the first year and 100% were dead by the second year. C. purpureum was thus as effective as the herbicide treatments Carbopaste and liquid glyphosate (12% Vision) and reduced resprouts to zero. Naturally occurring C. purpureum spores colonized about 40% of untreated cut stumps and about 20% of the stumps treated with chemical herbicides. The peak production of C. purpureum basidiocarps occurred about 22 months after the trial was established, with C. purpureum on 66% of treated stumps. The following year, the basidiocarps persisted on 23% of treated stumps. About 600 young red alder trees were cut to act as spore traps 2 years after trial establishment, when the most C. purpureum basidiocarps were present on treated stumps in the trial. These spore-trap trees were subsequently sampled, and PCR markers were used to verify and characterize 43 dikaryotic C. purpureum individuals, none of which were identified as the released isolate 2139. There was little difference in average band-sharing with the applied isolate among pre-trial (37% average) and spore-trap (38% average) populations. There was therefore no evidence that the C. purpureum strain applied inundatively to stumps in this trial was detectable on nontarget trees in the local area or had any measurable impact on the local C. purpureum population.     

Simultaneous determination of (R)- and (S)-naproxen and (R)- and (S)-6-O-desmethylnaproxen by high-performance liquid chromatography on a Chiral-AGP column

The glucuronides of the anti-inflammatory drug naproxen and its metabolite 6-O-desmethylnaproxen have been produced on a preparative scale by enzymatic synthesis. 6-O-Desmethylnaproxen, the glycine conjugate of naproxen and the O-sulphate of 6-O-desmethylnaproxen were prepared by chemical synthesis. Naproxen and the purified metabolite and conjugates were used as standards for the analytical investigation of the metabolic pattern of naproxen in humans. A reversed-phase high-performance liquid chromatographic method based on bare silica dynamically modified with cetyltrimethylammonium ions has been developed. The system was optimized to give a separation of naproxen, 6-O-desmethylnaproxen and five conjugates. Using this method it is also possible to deduce the relationship between the amount of the intact ether-glucuronide and acyl-glucuronide of 6-O-desmethylnaproxen.     

The effects of irrigation effluent on a Western Canadian prairie river

Field studies were conducted during the peak irrigation period(July–August) at the mouth, 50 m upstream and 50 m downstreamoffour irrigation return flows draining a 50 km stretch of theOldmanRiver in the short grass prairie zone of southern Alberta.Watersamples were analyzed weekly. Physico-chemical variableschangesonly slightly at each site but salinity and conductivity weresignificantly higher at the downstream site (Expanse Coulee)andall sites showed an increase over 1978 data. Conductivityalong theleft bank of the river was measured at 50 m intervalsdownstream ofExpanse Coulee until, after 1.5 km, it declined to theupstreamlevel which in the laboratory was shown to require a 660%dilutionof the effluent. In field experiments conducted at ExpanseCouleeit was shown that macroinvertebrate biomass was significantlylowerdownstream of the mouth and significantly higher upstream.Chlorophyll-a was not significantly different betweenthemouth and upstream with both significantly higher thandownstreamwhere it was not detectable. Inorganic carbon assimilation byepilithic algae and heterotrophic potential of the bacteriawereboth significantly higher at the mouth and upstream andsignificantly lower downstream.Organic matter in the sediment was not significantly differentupstream or downstream of the mouth but there was a higherpercentage of large particles (125–250 m) at the mouthanddownstream of EC a higher percentage of medium(60–125 m) andsmall (0–60 m) particles were found 50 m upstream. It isconcluded that at present differences in invertebrate biomass,chlorophyll-a, inorganic carbon assimilation byepilithicalgae and heterotrophic potential of epilithic bacteria atExpanseCoulee are not directly attributable to increase in salinitybutare more probably the result of increased suspended solids andsaltation.     

Aspects of breeding ecology of the eastern olivaceous warbler (Hippolais pallida)

The breeding ecology of eastern olivaceous warblers Hippolais pallida is poorly known. In this study, we provide data on nest site selection and breeding parameters of the species in a population in northwestern Bulgaria, the only one known to be regularly and heavily parasitized by the common cuckoo Cuculus canorus (hereafter cuckoo). Eastern olivaceous warblers only bred within human settlements of the study area, avoiding seemingly suitable habitat outside them. Nests were built in a wide range of plant taxa but ailanthuses Ailanthus altissima and mulberries Morus spp. were most frequently used (21%). After taking into account the availability of vegetation, there was an apparent preference for several plant taxa but not for mulberries. Mean nest height was 1.65 ± 0.98 (0.53–7.60) m, n = 217, and it varied significantly among different types of nesting substrate. Laying date and clutch size of first breeding attempts averaged 10 June ± 0.98 days, n = 101 and 3.9 ± 0.07 (2–5) eggs, n = 72, respectively. Hatching success, fledging success, and breeding success were 42.5, 86.4, and 36.7%, respectively. The main sources of nest mortality were predation and cuckoo parasitism, with no significant difference in the proportion of nests lost to each. Cuckoo parasitism seemed responsible for the relatively low hatching success in this population.     

Sucking and allosucking duration in farmed red deer (Cervus elaphus)

Sucking duration in ungulates does not only mean milk transfer, but is also associated with maternal care in general. It seems to be a reflection of offspring demand rather than solely milk transfer rate. Thus, the objective of this study was to discriminate between sucking and allosucking (i.e. sucking non-maternal hind) behaviour in red deer according to the sucking duration.We hypothesized that: (1) calves should suck longer from their mothers than allosuck from non-maternal hinds; (2) sucking duration of calves frequently nursed by a particular non-maternal hind should be longer than that of calves occasionally allonursed; (3) sucking duration should be longer for bouts including one calf than two or more calves sucking simultaneously; (4) male calves should suck and allosuck longer than female calves; and (5) primiparous hinds should nurse and allonurse longer than multiparous hinds. We observed sucking behaviour of 25 hinds and their 38 calves (from birth until the youngest calf reached one month of age) in two seasons. We recorded 1730 sucking bouts, of which 11.62% in the first season and 4.37% in the second season were non-filial. The duration of filial sucking was significantly longer than non-filial sucking. A large individual variance in the incidence of non-filial sucking in both the calves and hinds was found. Therefore, the non-filial hind–calf pairs were categorized in two clusters according to the frequency of nursing non-filial calves for one hind in relationship to all nursing events for this hind by a cluster analysis (PROC CLUSTER, SAS). We used a general linear mixed model, GLMM (PROC MIXED, SAS) to test the influence of hind relationship to the nursed calf (filial, frequently allosucking non-filial, or occasionally allosucking non-filial pair). Sucking duration of occasionally allosucking non-filial calves was only marginally different from that of filial calves. There was no difference between the two groups of non-filial calves. Multiple sucking bouts were shorter than those with one calf. Male calves sucked longer than female calves; however, the greatest difference was recorded between frequently allosucking non-filial pairs of both sexes. Frequently allosucking non-filial males sucked the longest and differently from occasionally allosucking non-filial males. Frequently allosucking non-filial females sucked the shortest and differently from filial calves of both sexes. It is more likely that allosucking seems to be more important for male rather than female calves.Therefore, it is concluded that allosucking calves differ in their sucking behaviour and two types of allosuckers (frequent and occasional) should be taken into account when analyzing allosuckling behaviour.