Hibernation Sites Research Articles

Electrophysiological responses from neurons of antennal taste sensilla in the polyphagous predatory ground beetle Pterostichus oblongopunctatus (Fabricius 1787) to plant sugars and amino acids

The responses of antennal contact chemoreceptors, in the polyphagous predatory ground beetle Pterostichus oblongopunctatus, to twelve 1–1000 mmol l −1 plant sugars and seven 10–100 mmol l −1 amino acids were tested. The disaccharides with an α-1.4-glycoside linkage, sucrose and maltose, were the two most stimulatory sugars for the sugar-sensitive neuron innervating these contact chemosensilla. The firing rates they evoked were concentration dependent and reached up to 70 impulses/s at 1000 mmol l −1. The stimulatory effect of glucose on this neuron was approximately two times lower. This can be partly explained by the fact that glucose exists in at least two anomeric forms, α and β. These two forms interconvert over a timescale of hours in aqueous solution, to a final stable ratio of α:β 36:64, in a process called mutarotation. So the physiologically active α-anomere forms only 36% of the glucose solution which was reflected in its relatively low dose/response curve. Due to the partial herbivory of P. oblongopunctatus these plant sugars are probably involved in its search for food, for example, for conifer seeds. Several carbohydrates, in addition to glucose, such as cellobiose, arabinose, xylose, mannose, rhamnose and galactose are known as components of cellulose and hemicelluloses. They are released by brown-rot fungi during enzymatic wood decay. None of them stimulated the antennal sugar-sensitive neuron. They are therefore not implicated in the search for hibernation sites, which include rotting wood, by this beetle. The weak stimulating effect (below 3 impulses/s) of some 100 mmol l −1 amino acids (methionine, serine, alanine, glutamine) to the 4th chemosensory neuron of these sensilla was characterized as non-specific, or modulating the responses of non-target chemosensory neurons.

Cave selection and use by swarming bat species

Caves are an important resource to a large proportion of temperate bat species, primarily as mating and hibernation sites. However, information on bat use exists for only a small fraction of caves in many parts of the temperate world, in part because current survey methods are inappropriate for many species. We surveyed the UK’s largest karst landscape, the Yorkshire Dales, by monitoring autumn swarming (mating) activity at 53 caves using automated echolocation call loggers, followed by trapping. Over 60% of caves surveyed were used by bats, but there was considerable variation in activity. Swarming activity was positively correlated with chamber development and negatively correlated with the amount of water the cave carried: together these two predictors explained 45% of the variance. Entrance orientation and shelter explained a further 10%. Activity was not correlated with entrance size, altitude or connectivity to the nearest summer habitat. All five resident swarming species were caught at most sites: Myotis brandtii, Myotis daubentonii, Myotis mystacinus, Myotis nattereri and Plecotus auritus. Behaviour, species composition and sex and age ratios were typical of swarming reported in other studies. Bat populations and catchment sizes were large and despite the proximity of other suitable caves, bats showed high fidelity to single sites. Our results show that the national importance of these caves has been overlooked. We suggest that survey for swarming activity is a quick and effective method of identifying underground bat sites and is likely to uncover many previously unknown and important sites throughout the temperate world.

Harmonia axyridis ladybug invasion and allergy

Beginning in 1916 Harmonia axyridis, an orange/red lady beetle with variable black spotting, was imported into the United States from Asia. This agricultural pest-control predator established independent feral populations in North America by 1988. Subsequently, Harmonia axyridis has become a pest to homeowners and various horticultural enterprises. Seeking winter hibernation sites, ladybug swarms invade human homes/habitats primarily in the fall. With increased Harmonia axyridis exposures, human ladybug allergy was first reported in 1998. Ladybug-specific IgE hypersensitivity has been reported in all ages (1-78 years old) and both sexes. Clinical ladybug allergy manifests variously as rhinoconjunctivitis, asthma, urticaria, and angioedema. A majority, but not all, allergic individuals are primarily exposed at home. Large fall swarms and smaller spring dispersions produce corresponding peaks in ladybug allergy. Ladybug hemolymph is a primary source of allergen. Har a 1 and Har a 2 major ladybug allergens have been characterized. Ladybug allergy prevalence in one endemic area was reported as 10%. Self-report of ladybug pests at home did not predict ladybug allergy, suggesting other exposures are important also. Some individuals have no history of atopy before manifestation of ladybug allergy. Ladybug, cat, cockroach, and house-dust mites are the most likely allergens to present as isolated single positive skin tests in an allergist's office. Ladybug should be a standard skin test allergen for all allergy patients tested in endemic areas. Avoidance of ladybug exposure is paramount to treatment.

Overwintering Site Selection by Short-Horned Lizards (Phrynosoma Hernandesi) in Northeastern Colorado

Radio telemetry was used to track 16 adult Short-Horned Lizards (Phrynosoma hernandesi) to their individual overwintering sites on the Central Plains Experimental Range (CPER) in Weld County, Colorado. Above-ground habitat characteristics of overwintering sites and randomly selected points within the study area were assessed. All individuals entered overwintering between 29 August and 19 September with a mean estimated entrance date of 7 September. Arrival of the first subzero nighttime air temperatures occurred shortly thereafter on 16 September. No lizard left its normal area of use to overwinter, and there was no tendency to aggregate. Lizards did not necessarily overwinter on warmer south-facing slopes; the proportion of overwintering sites oriented southward (0.62) was not different from random. Most lizards (75%) selected overwintering sites in the banks of washes that had relatively steep slopes and at specific locations where substrate was relatively bare and penetrable. Overwintering sites also tended to have a greater coverage of Yucca glauca (0.02%) than the general study area (0.01%). Analyses of historical soil temperature data from the CPER revealed that lizards would have to overwinter at a subsoil depth of about 1 m to avoid freezing temperatures. Banks that contain suitable hibernation sites that are located within an individual's normal area of use may be the habitat feature most important to successful overwintering.

Population size, catchment area, and sex-influenced differences in autumn and spring swarming of the brown long-eared bat (Plecotus auritus)

Swarming by bats is defined as intense autumnal flight activity in and near underground hibernation sites and is considered to be associated with mating, but this behaviour may also serve to allow bats to assess potential hibernacula. To test if swarms consist of resident bat populations from the surrounding area or transitional bat populations migrating between summer and winter areas, I measured activity patterns and the distribution of day roosts of swarming brown long-eared bats ( Plecotus auritus (L., 1758)) at two abandoned mines in southwestern Poland. Swarming occurred from mid-August to mid-October, and also in March and April. The maximum population of swarming bats was estimated to be about 500 individuals. The sex ratio was male-biased and was more skewed in spring than in autumn. Bats frequently travelled to the swarming site from day roosts as far away as 31.5 km. They usually stayed for several hours before returning to a day roost without visiting other hibernacula. Males roosted closer to the swarming site and visited it more frequently than females, consistent with increased mating attempts. My results suggest that swarming sites are hot spots for populations resident in the surrounding area. They likely play an important role in gene flow and facilitate mating among bats from spatially isolated populations.

Rodent predation on hibernating peacock and small tortoiseshell butterflies

Insects that hibernate as adults have a life span of almost a whole year. Hence, they must have extraordinary adaptations for adult survival. In this paper, we study winter survival in two butterflies that hibernate as adults and have multimodal anti-predator defences—the peacock, Inachis io, which has intimidating eyespots that are effective against bird predation, and the small tortoiseshell, Aglais urticae, which does not have an effective secondary defence against birds. We assessed predation on wild butterflies hibernating in the attic of an unheated house, as well as survival of individually marked butterflies placed by hand on different sites in the attic. Our objectives were to assess (1) the number of butterflies that were killed during hibernation, (2) whether survival differed between butterfly species, and (3) how predation was related to hibernation site and the identity of the predator. There was a strong pulse of predation during the first 2 weeks of hibernation: 58% of A. urticae and 53% of I. io were killed during this period. Thereafter, predation decreased and butterfly survival equalled 98% during the final 16 weeks of hibernation. There was no difference in survival between the two butterfly species, but predation was site-specific and more pronounced under light conditions in locations accessible to a climbing rodent, such as the common yellow-necked mouse, Apodemus flavicollis. We contend that small rodents are likely important predators on overwintering butterflies, both because rodents are active throughout winter when butterflies are torpid and because they occur at similar sites.

Monitoring Local Populations and Breeding Migration Patterns of the Gold-spotted Pond Frog, Rana chosenica

We monitored gold-spotted pond frog (Rana chosenica) populations near the Korea National University of Education in Chungbuk, Korea, from 19 May to 8 August, 2006 to examine the spatial distribution of populations in local areas and to investigate patterns of migration of adult gold-spotted pond frogs from terrestrial hibernation sites to breeding sites, We captured individuals from the largest population using a drift fence with 22 pitfall traps surrounding the breeding site. A total of 22 individuals (19 males and 3 females) were captured between 23 May and 15 June. No peak in breeding migration was detected, but the onset of the breeding migration may correspond with increased humidity. Male body weights were negatively correlated with sampling dates. Seven of 22 individuals were captured at the 4th pitfall trap, which was placed between two culverts. The capture rate per pitfall trap was higher in traps close to the rice field banks (1.44, traps <TEX>$1{\sim}9$</TEX>) than in traps facing hilly land (0.33, traps <TEX>$13{\sim}18$</TEX>). Comparative data from the Korean frog (Rana coreana), a sympatric species in the study area, were also collected and compared with those of the gold-spotted pond frog.

Autumn acaricide applications as a new strategy to control the pear leaf blister mite Eriophyes pyri

The pear leaf blister mite Eriophyes pyri (Pagenstecher) causes severe damage to pear leaves and fruits. As mites are well sheltered from exposure to plant protection agents during summer and acaricide efficacy is reduced when temperatures are low in early spring, autumn acaricide applications were evaluated to control mites as they migrate to their hibernation sites. Post-harvest sulphur and mineral oil treatments were applied in September 2003 and mites were monitored in the following spring. Only the sulphur-treated trees were virtually free of blisters. Sulphur treatments showed an efficacy of 95.3% (one application) to 99.6% (three applications), whereas, mineral oil treatments only had an efficacy of 12.8% (one application) to 69.6% (three applications). That post-harvest sulphur applications could decontaminate heavily infested orchards was possible was confirmed by a large-plot trial in two orchards in 2004/2005.

Aggregation characteristics of three species of Coccinellidae (Coleoptera) at hibernation sites

Adults of some coccinellid species overwinter in aggregations consisting of many individuals. They may clump because adults are attracted to particular environmental stimuli and/or of an innate tendency to join conspecific individuals. Aggregation behaviour was studied in Coccinella septempunctata L., which forms small clumps, and Ceratomegilla undecimnotata (Schneider) and Hippodamia variegata (Goeze), which form large clumps. Adults were recorded at five hilltop hibernacula (400-1500 m altitude) in central Europe (50-51°N, 14-16°E) for periods up to 27 years. The hibernacula occur in areas sparsely covered with isolated grass tussocks or completely with stones. Numbers of adults recorded under each of 300-900 stones or among the stems of the grass tussocks were counted every year at each hibernaculum. The degree of aggregation was determined using Taylor's power law. The coccinellid distributions became more aggregated and the size of the aggregations increased as their abundance increased, less in C. septempunctata than in the other two species. Aggregations formed even in the absence of prominent structures, which may attract immigrants, and even when unoccupied stones or tussocks suitable for overwintering were available. Aggregations may be established and their size limited by the strength of the intrinsic preference to join conspecifics. The supposed advantage of aggregated overwintering must be greater than the risk associated with the easy spread of diseases.

HIBERNATION TEMPERATURES IN SEVEN SPECIES OF SEDENTARY BATS (CHIROPTERA) IN NORTHEASTERN EUROPE

During 30 years of observations carried out in over 1,000 underground and semi-underground bat hibernation sites in Estonia, air temperature was measured near sleeping bats. In 1978, the ‘lower critical temperature of hibernation’ (LCT) was determined for two boreal bat species, Plecotus auritus and Eptesicus nilssonii. The LCT was defined as the mean value calculated on the basis of temperatures at which animals of a certain bat species awoke as a result of temperature decrease at their sleeping sites. For the first species, the LCT was -2.24°C, while for the second it was -3.13°C. During the past 20 years, we have registered new records of minimum hibernation temperatures for the following four sedentary bat species: Eptesicus nilssonii (-5.3°C), Myotis dasycneme (-2.5°C), Myotis brandtii (-2.5°C) and Myotis nattereri (-1.0°C). The highest temperatures (up to +10.5°C) were recorded near bats sleeping in cellar-type shelters in October and November. As a result of research, we concluded that the upper li...

Genetic structure in a swarming brown long-eared bat (Plecotus auritus) population: evidence for mating at swarming sites

Plecotus auritus, a small, gleaning bat species, lives in small, isolated summer colonies in which both males and females show a high degree of natal philopatry. Despite this, colonies have high gene diversities and low inbreeding coefficients. It has been suggested that inbreeding is avoided because mating occurs during autumnal and spring swarming at hibernation sites. We tested this hypothesis by comparing microsatellite profiles, based on eight loci, of bats from six summer colonies and two swarming sites they were known to visit from radiotelemetry studies. We found high gene diversities (Hs = 0.77) at both swarming sites and summer colonies which were not statistically different. There was no detectable isolation by distance and FST was low (0.001). Together, these results suggest high gene flow between sites. Despite this, there was small but significant genetic differentiation amongst summer colonies and between summer colonies and the primary swarming site. We suggest that swarming is important for gene flow and for maintaining genetic diversity in this highly philopatric species and discuss possible reasons for the genetic differentiation observed. The identification and protection of swarming sites should be a major conservation priority for this and other temperate bat species.

Habitat Use and Activity of Prairie Kingsnakes (Lampropeltis Calligaster Calligaster) in Illinois

The natural history of Prairie Kingsnakes (Lampropeltis calligaster calligaster) is largely unknown because of their secretive nature. We radio-tracked 10 adult Prairie Kingsnakes (six males, four females) for one complete active season to determine activity patterns and habitat use in an area in Illinois that included forest, grassland, agricultural fields, and roads. The active season extended from approximately April to mid-October. Home ranges of males averaged over four times larger than those of females and usually included the individual's hibernation site. Males and females had similar activity levels throughout the season, with no differences in frequency of movement or distance traveled per move. Snakes were underground at least 73% of the 574 times they were relocated, suggesting most activity is nocturnal. Collectively, kingsnakes completely avoided agricultural fields and showed a preference for grasslands, but females were strongly associated with grassland edges along roads. This association with roadside edges, and failure of Prairie Kingsnakes to cross roads, suggests that roads may be barriers to movement—an observation consistent with recent evidence that roads can be barriers to movement, negatively affecting snakes in ways other than via direct mortality.

Activity following arousal in winter in North American vespertilionid bats

ABSTRACT Many bat species hibernate to conserve energy during winter and like all hibernators they commonly arouse. During these arousals, some bats may undertake activities away from the hibernation site. Systematic ecological studies of the frequency and purpose of winter activity in temperate zone bats of North America are rare and much of the literature involves observations of single individuals or unmarked populations. We review the available literature on winter activity among North American vespertilionid bats to highlight the paucity of data on this subject and to stimulate future research. Due to the lack of repeated, systematic studies on most North American species, the conclusions drawn are general or pertain only to parts of the geographical range of any species. We suggest that winter activity is ubiquitous among temperate zone bats, but the degree and purpose of activity varies greatly between and within species. In general, cave‐dwelling bats tend to be relatively inactive compared with tree and foliage roosting bats during winter. Cave‐dwelling and tree cavity‐dwelling species do not appear to feed, but they do drink and occasionally copulate during the hibernation period. Species that hibernate in foliage or leaf litter are the most active species during winter and may feed and drink throughout winter, although they probably do not copulate because of their solitary nature. We encourage researchers to conduct studies on all aspects of winter activity for North American vespertilionids across wide latitudinal and altitudinal gradients. We suggest studies in the near future be focused on estimating the energetic costs and benefits of winter activity through determination of the frequency and intensity of winter feeding activity and more thorough examinations of movements within and among caves. Studies on common, wide‐ranging species have the potential to illuminate large‐scale patterns and differences and should be favoured over studies on rarer species.

Scaling up population dynamic processes in a ladybird–aphid system

AbstractHere, we study how scaling up to the metapopulation level affects predictions of a population dynamics model motivated by an aphidophagous predator–aphid system. The model incorporates optimization of egg distribution in predatory females, cannibalism among their offspring, and self‐regulation of the prey population. These factors determine the within‐year dynamics of the system and translate the numbers of prey and predator individuals at the beginning of the season into their numbers at the end of the season at the level of one patch—one suitable host plant or a group of these. At the end of each season, all populations of prey and all populations of predators are mixed (this simulates aphid host‐alternation and ladybird migration to hibernation sites), and then redistributed at the beginning of the next season. Prey individuals are distributed at random among the patches as a “prey rain”, while adult predators that survived from the previous season optimize the distribution of their offspring, in that they prefer patches with sufficient amount of prey and absence of other predators. This redistribution followed by within‐season dynamics is then iterated over many seasons. We look at whether small‐scale trends in population dynamics predicted by this model are consistent with large‐scale outcomes. Specifically, we show that even on the metapopulation scale, the impact of predators on prey metapopulation is relatively low. We further show how the dates of predator arrival to and departure from the system affect the qualitative behaviour of the model predictions.

Seasonal abundance and mortality of Oebalus poecilus (Dallas) (Hemiptera: Pentatomidae) in a hibernation refuge

Oebalus poecilus (Dallas) is an important pest affecting irrigated rice in Rio Grande do Sul, Brazil. It hibernates during the coldest months of the year in refuges such as bamboo litter. This study examined O. poecilus hibernation to determine the causes of mortality during this period. The study was conducted in a 140 m(2) bamboo plantation located in a rice-growing area in Eldorado do Sul County (30 degrees 02 S and 51 degrees 23 W), RS. During June 2000 to April 2002, 63 samples of litter were taken in weekly or fortnightly intervals, and the number of bugs recorded in the laboratory. The arrival at the hibernation site (bamboo litter) began in the first fortnight of March, and was completed in the beginning of May. O. poecilus left this refuge from middle October to the end of December. Parasitism by tachinid flies and Beauveria bassiana (Bals.) Vuill. fungus were the most important mortality factors.

Hibernation Site Selection by Eastern Massasauga Rattlesnakes (Sistrurus catenatus catenatus) near Their Northern Range Limit

Abstract Hibernation sites at higher latitudes must protect snakes from colder conditions for longer periods of time. Because fewer locations are likely to be suitable, hibernation site availability may restrict the northern distribution of snakes. We considered overwinter mortality, hibernation site fidelity, and the abundance of suitable hibernation sites based on surface features to assess whether Massasauga Rattlesnakes are likely to be limited by hibernation site availability on the Bruce Peninsula, Ontario, Canada. We used three years of radio telemetry to locate 46 hibernation sites of 32 individual snakes. Snakes hibernated individually in old root systems, rodent burrows, and rock crevices in forested areas. Hibernation sites could be differentiated from forested areas generally available to snakes but not from locations with holes and crevices in the immediate vicinity of hibernation sites. Few snakes hibernated in the same location in consecutive years, although most (>70%) hibernated within 10...

Cave site contributions to vertebrate history

Vertebrate fossils from cave deposits and karst features are recorded as early as the Mississippian with later occurrences of Permian vertebrates from fissures in Oklahoma, Triassic/Jurassic faunas from Wales and southwest England and Eocene to Oligocene faunas from France. Plio-Pleistocene cave fossil sites are numerous and are well known worldwide. The sheltered depositional environment in caves has facilitated the preservation of geochemical information such as stable isotope ratios and DNA in the bone assemblages. Bat colonies and owl roosts, common around cave entrances, contribute to the bone accumulation and provide a good sample of the local smaller vertebrate fauna. The use of caves by mammals as shelters, hibernation sites or dens for young, with the inevitable death in situ of some individuals, provides a unique sample so that growth series and predator-prey relationships can be studied. Caves in upland areas, where other environments of deposition are lacking, preserve a record of animals from those areas that are undergoing erosion. Age determination of cave deposits poses problems because they are isolated from marine or more widespread continental sequences. Correlation must be based on biological similarities, radiometric dates or palaeomagnetic data. Within-cave correlations are often difficult to define because of collapse, channeling and re-deposition. Access to the surface, with multiple openings at different times, may add further complications.

New Data on Bats Hibernating in Underground Sites in Vilnius, Lithuania

Investigations into bat diversity and abundance were carried out in Vilnius in 2005. Ten bat hibernation sites were investigated in the city where six bat species were found: Daubenton's bat (Myotis daubentonii), pond bat (Myotis dasycneme), Brandt.s/whiskered bat (Myotis brandtii/mystacinus), brown long-eared bat (Plecotus auritus), barbastelle bat (Barbastella barbastellus) and northern bat (Eptesicus nilssonii). More than 820 bats roosted in Vilnius: Daubenton.s bats constituted 62.5 %, barbastelle bats – 11.1% and pond bats – 10.7%. Pond bats, Daubenton's bats and barbastelle bats made up the largest known hibernating populations in south-eastern Lithuania. Brandt’s/whiskered bats have been recorded in Vilnius hibernation sites for the first time.

AUTUMN MIGRATION AND SELECTION OF ROCK CREVICES AS HIBERNACULA BY BIG BROWN BATS IN COLORADO

Movements, distribution, and roosting requirements of most species of temperate-zone bats in autumn are poorly understood. We conducted the 1st radiotelemetry study of autumn migrations and prehibernation roost selection of bats in western North America. Big brown bats (Eptesicus fuscus, n ¼ 55) in the Poudre River watershed, Colorado, moved from low-elevation summer ranges to high-elevation locations in autumn, where they roosted in rock crevices during the period leading up to winter hibernation. We characterized rock crevices used as roosts in autumn at these higher elevations at microhabitat and landscape scales. We used logistic regression combined with an information theoretic approach to determine which variables were most important in roost selection. At the microhabitat scale, autumn roosts were higher to the ground above and below the exit point and were in deeper crevices that had more constant temperatures than randomly selected crevices. At the landscape scale, aspect of the hillside was important, with autumn roosts typically facing north–northwest. Autumn roosts fell into 2 categories: those used for a few days (transient roosts) and those used for � 7 days and presumed to be hibernacula. Temperature regimes in the presumed hibernacula appear to provide optimal conditions for use of winter torpor, whereas transient roosts may offer passive rewarming and energy savings for bats still active in early autumn. Elevational segregation of sexes also was documented in our region, with a preponderance of females found at lower elevations and males at higher elevations in summer. Sex ratios at higher elevations became even in autumn. Use of short elevational migrations and selection of hibernation sites in rock crevices may be a common overwintering strategy of insectivorous bats of western North America.

Winter ecology of the cabbage aphid Brevicoryne brassicae (L.) (Homo., Aphididae) and its parasitoid Diaeretiella rapae (McIntosh) (Hym., Braconidae: Aphidiidae)

Abstract: Flower strips near crops may stimulate natural enemies by the provision of nectar and hibernation sites. However, these habitats may also be beneficial for potential pest species. We investigated the dynamics of the cabbage aphid Brevicoryne brassicae (L.) (Homo., Aphididae) and its primary parasitoid Diaeretiella rapae (McIntosh) (Hym., Braconidae) in brussels sprout fields and adjoining flower plots in winter. A wide variety of 14 plant species were included in the study, each established as monoculture plots. Brussels sprout fields and flower plots were established at two sites. One site was located in an open agricultural landscape, the other in a landscape dominated by mixed forest. Brevicoryne brassicae and D. rapae were found on brussels sprout plants but not in the flower plots. Brevicoryne brassicae was initially more abundant in the open landscape, but as their densities declined rapidly in time, no living aphids were recovered at both sites by February. The density of aphids parasitized by D. rapae showed a similar trend, but densities of eight mummies per brussels sprout plant were still present by the end of February. These findings suggest that (i) flower species under investigation do not function as sources of B. brassicae and (ii) brussels sprout plants that are not harvested may not only harbour D. rapae populations that may sustain biological control, but are also likely to act as sources of B. brassicae infestation.