Higher Body Condition Index Research Articles

Inferring condition in wild mammals: body condition indices confer no benefit over measuring body mass across ecological contexts.

Many studies assume that it is beneficial for individuals of a species to be heavier, or have a higher body condition index (BCI), without accounting for the physiological relevance of variation in the composition of different body tissues. We hypothesized that the relationship between BCI and masses of physiologically important tissues (fat and lean) would be conditional on annual patterns of energy acquisition and expenditure. We studied three species with contrasting ecologies in their respective natural ranges: an obligate hibernator (Columbian ground squirrel, Urocitellus columbianus), a facultative hibernator (black-tailed prairie dog, Cynomys ludovicianus), and a food-caching non-hibernator (North American red squirrel, Tamiasciurus hudsonicus). We measured fat and lean mass in adults of both sexes using quantitative magnetic resonance (QMR). We measured body mass and two measures of skeletal structure (zygomatic width and right hind foot length) to develop sex- and species-specific BCIs, and tested the utility of BCI to predict body composition in each species. Body condition indices were more consistently, and more strongly correlated, with lean mass than fat mass. The indices were most positively correlated with fat when fat was expected to be very high (pre-hibernation prairie dogs). In all cases, however, BCI was never better than body mass alone in predicting fat or lean mass. While the accuracy of BCI in estimating fat varied across the natural histories and annual energetic patterns of the species considered, measuring body mass alone was as effective, or superior in capturing sufficient variation in fat and lean in most cases.

Blood analytes of hawksbill sea turtles (Eretmochelys imbricata) from Florida waters: reference intervals and size-relevant correlations

Assessments of health variables in wild animal populations have evolved into important tools for characterizing spatiotemporal population trends and fitness, effects of stressors, diseases, and ecosystem health. Blood as a sample matrix can be obtained fairly non-invasively in the field, with preservation and sample processing techniques that allow for readily available routine and advanced diagnostic testing of blood. For wild-caught hawksbill sea turtles (Eretmochelys imbricata) foraging in southeastern Florida, USA, the objectives of this study were to (1) establish reference intervals for hematological and 24 plasma biochemical analytes, (2) determine length-and body condition-specific relationships with blood analytes, and (3) determine how water temperature influenced plasma biochemical analytes. Reference intervals were established for clinically normal juvenile (n = 26) and subadult (n = 39) hawksbills, with descriptive data reported for adult turtles (n = 3). Although subadults (mainly captured at Palm Beach County) were heavier and larger with greater body depth, juveniles (mainly captured at Monroe County) had a higher body condition index. Positive length-specific correlations were identified for packed cell volume, eosinophils, aspartate aminotransferase, phosphorus, cholesterol, glutamate dehydrogenase, total protein, albumin, and globulins, with negative correlations including alkaline phosphatase, creatine kinase, calcium, calcium to phosphorus ratio, and glucose. Subadults had less frequent morphological features of red blood cell regeneration compared to juveniles. These findings provide insight into life-stage class differences regarding hematopoiesis, antigenic stimulation, somatic growth, dietary shifts, nutritional status, osmoregulation, metabolism, physical activity or stress levels, and possible habitat differences. Life-stage class is the likely driver for the observed blood analyte differences, in addition to influences from water temperature. The data herein offer baseline information for a snapshot in time for critically endangered hawksbills inhabiting the Florida reef system and for answering individual-and population-relevant questions of relevance to conservation and population management.

Host-Parasite Relationship-Nematode Communities in Populations of Small Mammals.

Simple SummaryIntestinal nematodes were analyzed in three small rodent species: Apodemus sylvaticus, Apodemus flavicollis, and Myodes glareolus. In total, 15 species of nematodes were identified. We studied the relationship between the parasitological parameters (individual parasite species richness IndPSR and individual parasite load IndPL) and morphological characteristics (body mass, body condition index BCI, and spleen mass). In all of the studied species, our results showed that animals in a better condition (BCI) had significantly higher parasite species richness, as we had expected. Furthermore, we showed that females of the same BCI as males were parasitized with more parasite species in A. flavicollis. Contrary to our expectations, the spleen mass did not reflect changes in the level of parasitism, but in M. glareolus, a smaller spleen was related to a higher parasite load. Since the spleen is just part of the complex immune response, it is possible that the presence of nematode parasite species provokes, in small rodent species, a response at the other levels of the immune system.Nematode burdens and variation in morphological characteristics were assessed in eighty-eight animals from three host species (Apodemus sylvaticus, Apodemus flavicollis, and Myodes glareolus) from eight localities in Serbia. In total, 15 species of nematodes were identified, and the overall mean parasite species richness (IndPSR) was 1.61 per animal (1.98 in A. flavicollis, 1.43 in M. glareolus, and 0.83 in A. sylvaticus). Furthermore, the studied host species significantly differed in individual parasite load (IndPL) and in the following morphological characters: spleen mass, body condition index (BCI), and body mass. We aimed to analyze the relationship between the burden of intestinal nematodes, on one hand, and the body conditions of the host and its capability to develop immune defends on the other. Spleen mass was considered as a measure of immune response. In all host species, larger animals with a better condition (higher BCI) were infected with more parasites species (IndPSR), while parasite load was not related to BCI. Only in A. flavicollis were males significantly larger, but females of the same sizes were infected with more parasite species. This female-biased parasitism is contrary to the theoretical expectation that males should be more parasitized, being larger, more active, with a wider home range. Although the spleen size was significantly correlated with body condition and body mass, IndPSR was not related to spleen mass in any studied species, but in M. galareolus, we found that a smaller spleen was related to higher infection intensity (IndPL).

Do oil palm plantations provide quality habitat for migratory birds? A case study from Mexico

Habitat loss and degradation represent a major threat to Nearctic-neotropical migratory birds in the tropics. Managed agroecosystems have the potential to mitigate some impacts of land conversion, however, we know little regarding the quality of expanding oil palm plantation habitat for migratory birds in the neotropics. In this study, we used sex and age ratios, body condition, fat deposition, and muscle mass to assess oil palm habitat quality for seven species of migratory songbirds. Specifically, we captured individuals in native forest fragments and oil palm plantations in the state of Tabasco, Mexico, during two winter seasons (2017–2018, 2018–2019), and compared differences in age and sex ratios, and condition indices between habitats. We found that, when differences occurred, most species exhibited indicators of better habitat quality in native forest (older males with higher body condition indices) when compared to oil palm. Our results suggest that age and sex ratios combined with measures of physiological condition can be used to assess habitat quality for Nearctic-neotropical migratory birds overwintering in modified landscapes. Importantly, determining a species’ territorial behavior is key when selecting a given indicator of habitat quality for each species, and in certain cases, more intensive approaches such as estimates of survival, territory size, and food availability may be needed. Our results suggest that management strategies that promote forest-like conditions in oil palm plantations will improve habitat quality for declining populations of Nearctic-neotropical migratory birds.

Variation in Species Composition, Size and Fitness of Two Multi-Species Sea Turtle Assemblages Using Different Neritic Habitats

The neritic environment is rich in resources and as such plays a crucial role as foraging habitat for multi-species marine assemblages, including sea turtles. However, this habitat also experiences a wide array of anthropogenic threats. To prioritize conservation funds, targeting areas that support multi-species assemblages is ideal. This is particularly important in the Gulf of Mexico where restoration actions are currently ongoing following the Deepwater Horizon oil spill. To better understand these areas in the Gulf of Mexico, we characterized two multi-species aggregations of sea turtles captured in different neritic habitats. We described species composition and size classes of turtles, and calculated body condition index for 642 individuals of three species captured from 2011 to 2019: 13.6% loggerheads (Caretta caretta), 44.9% Kemp’s ridleys (Lepidochelys kempii) and 41.4% green turtles (Chelonia mydas). Species composition differed between the two sites with more loggerheads captured in seagrass and a greater proportion of green turtles captured in sand bottom. Turtles in sand bottom were smaller and weighed less than those captured in seagrass. Although small and large turtles were captured at both sites, the proportions differed between sites. Body condition index of green turtles was lower in sand habitat than seagrass habitat; there was no difference for Kemp’s ridleys or loggerheads. In general, smaller green turtles had a higher body condition index than larger green turtles. We have identified another habitat type used by juvenile sea turtle species in the northern Gulf of Mexico. In addition, we highlight the importance of habitat selection by immature turtles recruiting from the oceanic to the neritic environment, particularly for green turtles.

Effects of Season, Gravidity, and Streamflow on Body Condition from Tail Width in Two Federally Listed Salamanders, Eurycea sosorum and E. tonkawae

In population studies, individual physiological metrics can reveal important aspects of ecology and act as indicators of overall population health. Body condition is frequently used as a metric of physiological status and commonly quantified as some function of mass relative to structural size. In this study, we examined the natural variation in body condition of two central Texas spelerpines (Eurycea sosorum and E. tonkawae: Plethodontidae) to understand their nutritional status as a function of environmental variability and reproductive condition. Rather than using a mass-based metric to generate a body condition index (BCI), we used residuals from a linear regression of tail width vs. body length measured from subject photographs taken from the dorsal perspective. Overall, mean BCI for both species was lowest in the winter and generally higher in spring and summer. Streamflow had a small positive effect on E. tonkawae BCI and a negative effect on E. sosorum BCI. Gravid individuals for both species had lower BCI during autumn and winter (when the proportion of gravid individuals was the greatest) than nongravid individuals. By contrast, the few gravid E. sosorum we observed in summer had higher BCI than nongravid individuals. Our results provide important baseline information on the ecology of these federally protected salamanders and demonstrate the utility of a BCI based on width instead of mass.

Haemosporidian parasites prevalence associated with physical conditioning of avian species from the Brazilian Cerrado

Blood parasites can infect myriad avian species and thereby affect the fitness and survival of their hosts. There is wide interspecific variation in parasite prevalence related to biological, ecological, and evolutionary host factors. This study aimed to determine the blood parasite prevalence in avian species from the Brazilian Cerrado and to investigate the associations among biomass, body condition, and blood parasitism. A total of 1,098 blood smears from 549 individuals (56 species) collected in four forest fragments were analyzed. Of these, 109 (19.85%) individuals from 33 species were infected: 13 (2.36%) were positive for Haemoproteus and 103 (18.76%) for Plasmodium. There was co-infection between both genera of parasites in 7 individuals. Among bird species, prevalence ranged from zero to 100%. There were significant positive correlations between prevalence and biomass and the body condition index. Hemosporid vectors track their hosts by carbon dioxide detection. Since large organisms emit more carbon dioxide, our results suggest that larger birds may be more susceptible to hemosporid vectors. Additionally, species with higher body condition indices can be more tolerant to parasites, possibly because they have more energy reserves. This study showed that species with higher biomass and body condition indices were associated with higher blood parasite prevalence, a finding that suggests these factors are efficient predictors to explain the interspecific variations. This information could be important for the understanding parasite-host relationships and useful for bird conservation programs.

Heat, health and hatchlings: associations of in situ nest temperatures with morphological and physiological characteristics of loggerhead sea turtle hatchlings from Florida.

Incubation temperatures, in addition to an embryo’s genetic makeup, are critical in many aspects of adequate sea turtle embryonic development. The effects of high and low incubation temperatures on hatchling quality have been previously examined; however, many of these studies were conducted on relocated or laboratory-reared nests, which do not accurately reflect natural nest temperature fluctuations. To observe the impacts of varying in situ incubation temperatures on loggerhead sea turtle (Caretta caretta) hatchling morphology, various health variables and locomotor performance, temperature data loggers were deployed in 15 loggerhead nests on Juno Beach, Florida, between May and July 2018. Over the course of the study period, 10 morphological traits were measured, blood analytes and heart rate were assessed for the establishment of reference intervals and the self-righting response in seawater was evaluated. Warmer months were associated with smaller body size and higher body condition index, larger umbilical scar size, slower righting time, lower heart rates and higher packed cell volume, hemoglobin, total solids, total white blood cell count, absolute heterophils and absolute basophils. These findings provide evidence that higher in situ incubation temperatures have the potential to adversely affect hatchlings from warmer nests due to increased risk of predation from smaller body sizes, decreased physical responses and overall fitness, altered hemodynamic balance (e.g. dehydration) and potential inflammation and/or stress. With rising temperatures, we predict sea turtle hatchlings may have increasing risks of developing suboptimal physiological features affecting overall fitness and ultimately survival. These results demonstrate that rising environmental temperatures can negatively impact sea turtle hatchlings, thus representing additional stress on sea turtle populations and contributing to our understanding of potential pathophysiological effects of climate change on the delicate life-stage class of the sea turtle hatchling. This information will be useful for formulating effective future sea turtle management plans.

Do feather traits convey information about bird condition during fall migration?

Long-distance migration is energetically costly and often has a significant impact on bird health and condition. Therefore, understanding the health status of birds during long-distance migration is of ecological interest; however, obtaining invasive health measures is not always feasible or practical. Bird feathers can provide information about individual bird condition independent of invasive and expensive blood tests and have been used previously as indicators of condition, even long after the season of feather growth. Here, we investigated this question using 2 migratory songbirds in North America, Western Palm Warblers (Setophaga palmarum palmarum), which have conspicuous white patches on their tail feathers, and Gray Catbirds (Dumetella carolinensis), which have prominent daily growth bars on their tail feathers. Feathers were collected from birds captured on Jekyll Island, Georgia, during their fall migration. From the feathers we quantified the size of white patches on warbler rectrices and estimated growth bar length (as an index of feather growth rate) on catbird rectrices using image analysis. We also obtained 2 measures of bird health for each species: estimates of white blood cell abundance from blood smears (immune status) and size-corrected body mass (body condition). Analyses of feather traits and how they relate to bird health indicated that warblers (n = 42) with larger white patches had significantly higher body condition indices, although no association with white blood cell abundance, and catbirds (n = 27) with faster feather growth had significantly lower white blood cell abundance, but no association with body condition. Given the utility of these feather characteristics, our results suggest these metrics can be used to provide some insights into the biology of songbirds during one of the most critical portions of the annual cycle, migration.

Persistent organic pollutants in fat of three species of Pacific pelagic longline caught sea turtles: Accumulation in relation to ingested plastic marine debris

In addition to eating contaminated prey, sea turtles may be exposed to persistent organic pollutants (POPs) from ingesting plastic debris that has absorbed these chemicals. Given the limited knowledge about POPs in pelagic sea turtles and how plastic ingestion influences POP exposure, our objectives were to: 1) provide baseline contaminant levels of three species of pelagic Pacific sea turtles; and 2) assess trends of contaminant levels in relation to species, sex, length, body condition and capture location. In addition, we hypothesized that if ingesting plastic is a significant source of POP exposure, then the amount of ingested plastic may be correlated to POP concentrations accumulated in fat. To address our objectives we compared POP concentrations in fat samples to previously described amounts of ingested plastic from the same turtles. Fat samples from 25 Pacific pelagic sea turtles [2 loggerhead (Caretta caretta), 6 green (Chelonia mydas) and 17 olive ridley (Lepidochelys olivacea) turtles] were analyzed for 81 polychlorinated biphenyls (PCBs), 20 organochlorine pesticides, and 35 brominated flame-retardants. The olive ridley and loggerhead turtles had higher ΣDDTs (dichlorodiphenyltrichloroethane and metabolites) than ΣPCBs, at a ratio similar to biota measured in the South China Sea and southern California. Green turtles had a ratio close to 1:1. These pelagic turtles had lower POP levels than previously reported in nearshore turtles. POP concentrations were unrelated to the amounts of ingested plastic in olive ridleys, suggesting that their exposure to POPs is mainly through prey. In green turtles, concentrations of ΣPCBs were positively correlated with the number of plastic pieces ingested, but these findings were confounded by covariance with body condition index (BCI). Green turtles with a higher BCI had eaten more plastic and also had higher POPs. Taken together, our findings suggest that sea turtles accumulate most POPs through their prey rather than marine debris.

Spatio-temporal variation in the body condition of female pied flycatcher (Ficedula hypoleuca) in a polluted environment

Food-chain changes in urban and industrial sites may limit breeding-time resources (e.g. food availability) for small insectivorous passerines. We used a long-term data set of pied flycatchers (Ficedula hypoleuca), collected from one of the most polluted sites in Finland during the past 23 years to study the effects of metal pollution on body condition of breeding females. Our results show that body mass started to decline already some days before hatching, indicating a preparation of females to forthcoming chick feeding period. We did not find long-term temporal trends in female body condition index (BCI) in spite of considerably reduced metal emissions during the study period. However, females had higher BCI in polluted than in unpolluted areas during the incubation period. For both incubation and nestling periods the body condition was lower for later breeders, though the condition index decreased slightly faster in relation to hatching date in polluted areas, which may be due to more drastic decrease in nutrition rich food abundance. Temperature and clutch size were positively associated with BCI during the incubation period, but not in the nestling period. Overall, our data suggest that environmental pollution modifies important life-history traits, potentially via indirect effects of higher environmental variability and changed phenology in polluted environment.

Tolerance to hypoxia in Asian green mussels, Perna viridis, collected from a ship hull in the non-native range in eastern Indonesia

Tolerance to fluctuating environmental conditions is regarded as a key trait of successful marine invasive species as it presumably promotes survival in recipient habitats, which are often anthropogenically impacted systems such as harbours. Little is known, however, about how transport of fouling organisms on ship hulls influences the condition of the transported individuals and how this is related to their tolerance to environmental stress. We investigated the influence of transport on a ship hull on the ability of Asian green mussels, Perna viridis, to survive low concentrations of dissolved oxygen (0.5 and 1 mg/l DO). This was done by comparing the performance under stress in mussels from a eutrophic habitat in Jakarta Bay to that of mussels that had spent their lifetime on a passenger ferry crossing the Indonesian Archipelago from Jakarta in the west to West Papua in the east. We found that the mussels that came from the eutrophic habitat survived twice as long as mussels from the ferry when exposed to low oxygen concentrations. Mussels collected from the ferry, however, had a generally higher byssus production under experimental conditions, which can be attributed to their life on a moving object where they are exposed to drag. We suggest that Jakarta Bay mussels survived oxygen stress longer because they had higher Body Condition Indices than their conspecifics from the ship hull and thus had more energy available for stress compensation. These results show that transport on ship hulls can weaken the robustness of P. viridis, if the journey leads the ship through areas of low food supply for mussels, if the stopovers in eutrophic coastal ecosystems are short and if the sailing times are long (several weeks). This finding might explain the lack of establishments of P. viridis in tropical areas of Australia, from where repeated incursions have been reported.

ANTHROPOGENIC IMPACTS ON YELLOW-SPOTTED RIVER TURTLE Podocnemis unifilis (REPTILIA: PODOCNEMIDIDAE) FROM THE BRAZILIAN AMAZON

The purpuse of this study was to investigated the influence of anthropogenic impacts on Podocnemis unifilis nesting on a stretch from Falsino river, with two forest reserves, and one urban area on the Araguari river, state of Amapa, eastern Amazon (Brazil). A total of 180 nests were found, being 89.4 % in the forest reserves and only 10.6 % in urban areas. On Falsino river, we observed a spawning pattern, because the number of nests was correlated to the length and width of the nesting locations. On Araguari river, the P. unifilis nests were generally found in areas with surrounding vegetation up to 5 meters in height, minimum distance of 120 meters from residences and immediately or after places of higher exploration of pebbles. Females from Falsino river had smaller eggs, but the neonates were bigger and with higher body condition index than the neonates from Araguari river. About 80 % of the nests were prey, mostly because of the large collection of eggs for feeding. Furthermore, it was found that adult turtle hunting has been intense. Although one of the areas is in forest reserves, the human impacts were similar to those caused in urban areas, indicating the need to implement protection programs for the conservation of P. unifilis.

Introduced Pacific oysters Crassostrea gigas in South Africa: demographic change, genetic diversity and body condition

Successful aquaculture species are often chosen for their fast growth rates and fecundity, which are also characteristics of invasive species. The Pacific oyster Crassostrea gigas, which constitutes 80% of global oyster trade, has been confirmed as invasive in 17 of the 66 countries where it is cultured. The single study of its status in South Africa reported populations in six South Coast estuaries in 2001, dropping to three sites in 2003. We resurveyed these estuaries, visited others in the Eastern and Western Cape provinces, and sampled oyster tissue for molecular analyses of population structure. Pacific oysters have disappeared from Knysna and, following our collections, possibly also from the GouKou Estuary. Between 2003 and 2012, the Breede Estuary population decreased by 87%, from an estimated 184 206 to 23 760 individuals. Within this estuary, oysters 12 km upriver had denser shells and higher body condition indices than did those within 1.4 km of the river mouth, presumably reflecting higher availability of suspended organic matter. However, low salinity over most of the species’ range in the estuary probably inhibits recruitment. New populations of Pacific oysters in the Swartkops and Kaaimans estuaries urgently require monitoring and eradication. Haplotype (h) and nucleotide (π) diversities across all oyster populations sampled (h = 0.2300 [SD 0.0595], π = 0.0006 [SD 0.0007]) were lower than those of co-occurring indigenous Cape rock oysters Striostrea margaritacea from the GouKou and Breede estuaries (h = 0.9076 [SD 0.0386], π = 0.00589 [SD 0.00347]). Pacific oysters either have been introduced to South African estuaries infrequently, or have experienced genetic bottlenecks following river floods or human exploitation, or both. Populations growing outside culture infrastructure are restricted to estuaries in the Eastern and Western Cape provinces, with no evidence of occurrence in fully marine shelf environments. Given the species’ considerable socio-economic importance, estuarine and coastal surveillance coupled with aquaculture zoning are required to integrate biodiversity and food security considerations.

Reproductive patterns of European pond turtles differ between sites: a small scale scenario

From 1996 to 2002, we studied the body size, measures of reproductive strategy (relative clutch mass and delayed reproduction at sexual maturity), and reproductive output (clutch frequency and annual egg production) of female European Pond turtles,Emys orbicularis, at two sites separated by 12 km in central Mediterranean Tuscany (San Rossore and Camp Darby, central northern Italy). Females did not reproduce at the first appearance of external sexual characters, but reproduced at larger sizes, probably as older turtles. Among years, reproductive females were more common than were non-reproductive females, yet both groups had similar body sizes. Body size (carapace length and width, plastron length and width, shell height and body mass) varied between localities and among years. Body size differed between reproductive and non reproductive females in Camp Darby, but not in San Rossore females. Shell volume did not vary among years, nor between localities, nor between reproductive status. Reproductive females had higher body condition indices (BCI) than did non-reproductive females, while BCI did not differ between females laying one clutch and females laying multiple clutches. Clutch size did not vary among years. One clutch per year was much more frequent than multiple clutches, and multiple clutches were more frequent in Camp Darby than in San Rossore females, likely due to differences in population structures between sites.

Morphometrics and Body Condition Index of Eurasian Collared-Dove and Mourning Dove in Durango, Mexico

In order to incorporate the knowledge of two species of wild doves and compare the results of both, we assessed morphometrics (body weight, bill, tarsus, tail, wing, head and culmen length) and body condition index (using weigh, wing, tail and tarsus length) of Eurasian Collared-Dove Streptopelia decaocto and Mourning Dove Zenaida macroura (Aves: Columbidae) based on 40 specimens of each species collected during fall-winter 2013 and spring-summer 2014 in the municipality of Durango, Durango, Mexico. We found that body condition index was higher during fallwinter for both species. We also found size dimorphism. Males of Eurasian Collared-Dove were larger than females in head length (p = 0.002) and tail length (p = 0.05) but smaller in culmen length. Female Mourning Doves had a higher body condition index compared to males (p = 0.02) during both seasons. As expected, Eurasian Collared-Dove was larger in all measurements than Mourning Dove (p > 0.05) but tail length (p = 0.12).

Does despotic behavior or food search explain the occurrence of problem brown bears in Europe?

Bears foraging near human developments are often presumed to be responding to food shortage, but this explanation ignores social factors, in particular despotism in bears. We analyzed the age distribution and body condition index (BCI) of shot brown bears in relation to densities of bears and people, and whether the shot bears were killed by managers (i.e., problem bears; n = 149), in self-defense (n = 51), or were hunter-killed nonproblem bears (n = 1,896) during 1990–2010. We compared patterns between areas with (Slovenia) and without supplemental feeding (Sweden) of bears relative to 2 hypotheses. The food-search/food-competition hypothesis predicts that problem bears should have a higher BCI (e.g., exploiting easily accessible and/or nutritious human-derived foods) or lower BCI (e.g., because of food shortage) than nonproblem bears, that BCI and human density should have a positive correlation, and problem bear occurrence and seasonal mean BCI of nonproblem bears should have a negative correlation (i.e., more problem bears during years of low food availability). Food competition among bears additionally predicts an inverse relationship between BCI and bear density. The safety-search/naivety hypothesis (i.e., avoiding other bears or lack of human experience) predicts no relationship between BCI and human density, provided no dietary differences due to spatiotemporal habitat use among bears, no relationship between problem bear occurrence and seasonal mean BCI of nonproblem bears, and does not necessarily predict a difference between BCI for problem/nonproblem bears. If food competition or predation avoidance explained bear occurrence near settlements, we predicted younger problem than nonproblem bears and a negative correlation between age and human density. However, if only food search explained bear occurrence near settlements, we predicted no relation between age and problem or nonproblem bear status, or between age and human density. We found no difference in BCI or its variability between problem and nonproblem bears, no relation between BCI and human density, and no correlation between numbers of problem bears shot and seasonal mean BCI for either country. The peak of shot problem bears occurred from April to June in Slovenia and in June in Sweden (i.e., during the mating period when most intraspecific predation occurs and before fall hyperphagia). Problem bears were younger than nonproblem bears, and both problem and nonproblem bears were younger in areas of higher human density. These age differences, in combination with similarities in BCI between problem and nonproblem bears and lack of correlation between BCI and human density, suggested safety-search and naïve dispersal to be the primary mechanisms responsible for bear occurrence near settlements. Younger bears are less competitive, more vulnerable to intraspecific predation, and lack human experience, compared to adults. Body condition was inversely related to the bear density index in Sweden, whereas we found no correlation in Slovenia, suggesting that supplemental feeding may have reduced food competition, in combination with high bear harvest rates. Bears shot in self-defense were older and their BCI did not differ from that of nonproblem bears. Reasons other than food shortage apparently explained why most bears were involved in encounters with people or viewed as problematic near settlements in our study.

Is parasite load dependent on host aggregation size? The case of the greater mouse-eared bat Myotis myotis (Mammalia: Chiroptera) and its parasitic mite Spinturnix myoti (Acari: Gamasida)

The risk of parasite infection grows with the size of host aggregations, which, in turn, may also depend on host sex and age and the quality of environmental resources. Herein, we studied the relationship between ectoparasitic infections with the wing mite (Spinturnix myoti) and the size of the breeding colonies, sex, age, and body condition index (BCI) of its host, the greater mouse-eared bat (Myotis myotis). The influence of environmental quality in the Carpathian Mountains (Poland) was also examined. We found significant differences in mite abundance and BCI between different breeding aggregations of the greater mouse-eared bat and also between the host sex/age categories. The most heavily infected bats were adult M. myotis females, while young males appeared to be the least infected. The BCI differed significantly between the sexes in young bats (males had a higher BCI than females) and also between colonies. No significant differences in the BCI were found for adult females. We did not find any relationship between the infestation rate of M. myotis, their colony size, the quality of environmental resources (percentage of forest cover around the colony), or the BCI. The prevalence of the various developmental stages of the mites did not differ between the host sex/age categories; however, differences were found in the sex ratios of deutonymphs and adult mites between adult M. myotis females. We predict that parasite load may not be dependent on colony size itself, but mainly on microclimatic factors, which are in turn directly correlated with colony size.

Survival of captive-bred skinks following reintroduction to the wild is not explained by variation in speed or body condition index

Translocation is a common conservation tool and often involves founders that are reared in captivity. Why some translocations succeed and others fail is not well understood, but may be related to phenotypic changes brought about by captivity. We found that variation in speed and body condition index among a small group of captive-reared Otago skinks (Oligosoma otagense) did not influence their survival after release to the wild. In the first 12 months, 75% of skinks persisted, and this reduced to 58% by 18 months. After combining our results with data for other Oligosoma species, we found that captive-reared skinks pre-release have a higher body condition index and are about 50% slower than wild lizards; however, slower speeds are not consistently associated with higher body condition indices. We suggest that reduced speeds of captive lizards are a function of physiological and behavioural changes associated with captivity, but not necessarily obesity.

Cuckoldry features of introduced pumpkinseed sunfish (Lepomis gibbosus) in contrasting environmental conditions in southern Europe

Reproduction of pumpkinseed sunfish ( Lepomis gibbosus (L., 1758)) in the species’ native range often involves cuckoldry, consisting of dominant nest-guarding (parental) males and the participation by small “sneaker” males. However, it remains unknown whether this behaviour occurs in populations of non-native pumpkinseed. Thus, the present study describes the phenotypic features of cuckoldry under contrasting environmental conditions (lentic versus lotic) in southern Europe. Parental and sneaker pumpkinseeds were captured in the summer of 2011 from the River Bullaque (central Spain) and from the Encinarejo Reservoir (southern Spain). No differences in total length were observed in sneaker males, although individuals of ages 1+ and 2+ were significantly predominant in the river and the reservoir, respectively. Parental males were larger and older in the reservoir than in the river. Gonadosomatic and hepatosomatic indices were significantly higher in sneaker than in parental males at both sites. Body condition was lower in sneaker males in the river. Both ingested biomass and the proportion of full stomachs were lower in parental males at both sites, being significant in all cases except ingested biomass in the river. Sneaker males achieved a higher gonadosomatic index than parental males. In contrast, parental males had higher body condition indices than sneakers. Results demonstrate the high ecological plasticity of pumpkinseed sunfish to display natural behaviours out of its native area.