Hibernation Sites Research Articles

On the parasitization of the ladybird Coccinella septempunctata L. (Col., Coccinellidae)

Abstract: The present study deals with entomoparasites of Coccinella septempunctata L. in cereals, mainly in winter wheat. Sections of monthly sampled adult ladybirds during one year in different habitates at Staaken (Berlin) gave two peaks of parasitization with Perilitus coccinellae (Schrank) (Hym., Braconidae): (1) 33% in March (hibernation site); and (2) 12.5% in June (winter wheat). Populations of the ladybird investigated during the seasons in 1993 and 1994 in winter wheat at three locations (Berlin‐Staaken, Fläming, Magdeburger Börde) showed a similar sharp increase in degree of parasitization with Perilitus coccinellae in the second half of June. Maximum of parasitization reached from 12.3% (Fläming, 1993) to 25% (Börde, 1993) and was a result of the act of the first newly emerged adult wasps. Main parasite of the coccinellid pupae was Phalacrotophora fasciata (Fallen) (Dip., Phoridae) with parasitization rates between 4.9% (Börde) and 20.2% (Fläming). Oomyzus scaposus (Thompson) (Hym., Eulophidae, Tetrastichinae) was found only at two locations with low rates: 0.9% (Fläming) and 1.4% (Berlin). Experiments in climatic chambers with alternating temperatures gave new results for the effect of Perilitus on the fertility of matured female ladybirds. At relatively high temperatures (25°C middle of day) daily numbers of coccinellid eggs increased for a period of a week immediately after parasitization. Though mortality was high (70.6%) at this condition, half of the surviving females began egg deposition 12 days after emergence of the Perilitus larva.

Terrestrial Buffer Zones and Wetland Conservation: A Case Study of Freshwater Turtles in a Carolina Bay

Because freshwater wetlands often support diverse and unique species assemblages, wetland loss is a primary concern in biological conservation. U. S. federal statutes protect many wetlands by deterring development within delineated borders that segregate wetland habitats from upland regions. In addition, some state and local jurisdictions mandate buffer zones that afford varying levels of protection to upland habitats adjacent to wetlands. We used geographic information system analysis to test the adequacy of federal and state wetland protection statutes by determining the degree to which protected acreage encompassed the habitats freshwater turtles needed to complete their life cycles. Two critical life‐cycle stages, nesting and terrestrial hibernation, occurred exclusively beyond wetland boundaries delineated under federal guidelines. The most stringent state buffer zone insulated 44% of nest and hibernation sites. Our data indicate that the freshwater turtles examined in this study required a 275‐m upland buffer zone to protect 100% of the nest and hibernation sites. Insulating 90% of the sites required a 73‐m buffer zone. We suggest that the habitat needs of freshwater turtles demonstrate the dependence of wetland biodiversity on the preservation of adequate amounts of upland habitats adjacent to wetlands.

Variable fortunes in a patchy landscape —The habitat templet of an insect migrant

AbstractMigration by flight is essential for insects living in patchy landscapes and knowledge about variability in habitat patch structure and quality is important for the development of theory concerning insect dispersal polymorphisms. However, few studies provide more than anecdotal evidence about habitat change in time and space and its effects on insect survival and reproduction. Here I show how habitats and resource density of a lygaied bug, Lygaeus equestris, change in a patchy landscape over a seventeen year period. Although habitat patches per se are very stable, there are large temporal fluctuations in per capita food resources. Food seems to be limiting only in some years, and there may be periods of several years when populations change due to weather disturbance. Between‐patch variation in reproductive success is large. Furthermore, the relative favourability of patches changes between years. There are also distance effects; in some years distances to suitable hibernation sites affect reproductive success. Long fliers experience more variable success, and sometimes extreme success, when compared with short fliers. The importance of movements from outlying areas also changes with time. The insect is thus faced with a habitat templet which varies strongly on many temporal and spatial scales.

Variations in body length, weight, fat content and survival in Coccinella septempunctata at different hibernation sites

AbstractAdults of Coccinella septempunctata L. (Coleoptera; Coccinellidae) were sampled in four overwintering sites: one in England and three at different altitudes in the Czech Republic (350–1420 m above sea level) in autumn 1992 and spring 1993. Body length, dry weight and fat weight were measured. There were significant differences in body length between sampling sites in spring 1993, but not in autumn 1992. The average sex ratio (♀) in all samples was 1:0.60 in 1992 and 1:0.72 in 1993. Females were significantly larger and heavier, and contained more fat than males in both sampling periods. Dry weight and fat weight were positively correlated to body length at all sampling sites except at Ruzyne, in the Czech Republic. Adults hibernating at higher altitudes and away from their breeding and feeding habitats had significantly more fat than those hibernating at lower altitudes. Fat reserves were reduced by 30% during the hibernation at the top of the Krkonose mountain, in the Czech Republic, where temperatures were much lower, but more than half of the fat reserves were consumed during the overwintering period at the other sampling sites. The significance of body length and fat reserves in relation to adult hibernation sites and overwintering survival is discussed.

Seasonal variation in local abundance of adults of the large pine weevil, Hylobius abietis L. (Col., Curculionidae)

AbstractThe abundance of adult H. abietis was studied over a 6‐month period at a clear‐fell site in Kielder Forest, Northumberland, UK. Numbers varied markedly over the study period, peaking in August. Using enclosure and exclosure techniques it was estimated that most of the beetles captured at the study site emerged from the soil or from the stumps present at the site. Weevil abundance declined from September onwards and by the end of November, no more weevils were trapped, presumably due to movement away to hibernation sites. The implication of these findings for pest management strategies is highlighted.

Parasitoid induced digging behaviour in bumblebee workers

Abstract. Insects affected by parasitoids can alter their behaviour after infection; however, it is not always obvious whether the changed behaviour increases the fitness of the host or the fitness of the parasitoid. Workers of Bombus terrestris containing an endoparasitoid larva (Diptera: Conopidae) dug into the soil before they died. This digging behaviour resulted in the selection of a protected hibernation site for the parasitoid pupa and represented a selective advantage for the parasitoid, because hibernation in the soil led to larger and heavier adult flies, showing fewer malformations in wings than flies hibernating on the ground. The observed digging behaviour of parasitized bumblebee workers enhanced parasitoid fitness only, while its effects on host fitness were neutral.

Dehydration tolerance in wood frogs: a new perspective on development of amphibian freeze tolerance.

Wood frogs, Rana sylvatica, tolerate the loss of 50-60% of total body water during experimental dehydration. The rate of water loss for unprotected frogs is the same whether animals are frozen (at -2 degrees C) or unfrozen (at 1 degrees C) but is greatly reduced when frogs are frozen under a protective layer of moss. Dehydrational death could occur in as little as 7-9 days for unprotected animals; this indicates the importance for winter survival of selecting well-protected and damp hibernation sites. Prior dehydration affected the cooling and freezing properties of frogs, reducing supercooling point and the amount of ice formed after 24 h at -2 degrees C and acting synergistically with freezing exposure in stimulating cryoprotectant synthesis. Analysis of the effects of controlled dehydration at 5 degrees C showed that changes in body water content alone (without freezing) stimulated liver glycogenolysis and the export of high concentrations of glucose into blood and other organs. Autumn-collected frogs dehydrated to 50% of total body water lost showed glucose levels of 165-1,409 nmol/mg protein in different organs, increases of 9- to 313-fold compared with control values and reaching final levels very similar to those induced by freezing exposure. The data support the proposal that various adaptations for natural freeze tolerance may have been derived from preexisting mechanisms for dealing with water stress in amphibians and that cell volume change may be one of the signals involved in triggering and sustaining molecular adaptations (e.g., cryoprotectant output) that support freezing survival.

Metabolic rates of wintering Blanding's turtles, Emydoidea blandingii

1. 1. Aquatic .VO 2 of three adult Blanding's turtles ( Emydoidea blandingii) wintering at 3°C on the bottom of a small Massachusetts pond was 0.342 ± 0.012 gml O 2/g/hr ( x ̄ ± SE ). 2. 2. This moderate rate of metabolism, compared with that of other species at low water temperature, is probably correlated with the physical characteristics of the hibernation site and the amount of movement demonstrated by wintering animals.

Modified Cave Entrances: Thermal Effect on Body Mass and Resulting Decline of Endangered Indiana Bats (Myotis sodalis)

Entrances to many caves occupied by the endangered Indiana bat (Myotis sodalis) have been modified to control human access. We show that modifying cave entrances can degrade the bats’ winter habitat, we demonstrate one mechanism by which this damage occurs, and we document a restoration experiment. We compared a large bar population in an unmodified cave with a small, reduced bat population in a cave with warm winter temperatures resulting from an entrance wall that impeded air exchange. In the modified cave, mean winter temperature at the hibernation site was 5.0° C higher than in the unmodified cave, bats entered hibernation at a 5% higher body mass, bats lost 42% more mass and the frequency distribution of late‐winter mass was truncated, with no bats weighing less than 5.4 g. The results describe unacceptable extremes for hibernation: subfreezing temperatures and warm temperatures causing mass‐loss rates of more than 0.009 g/day. Over a decade following removal of the entrance‐constricting wall, the population increased from 2,000 to 13,000 bats. Previous recommendations, based on common‐sense observation, to open blocked cave entrances are confirmed by this study. The similar case of Coach Cave, Kentucky, offers the potential for recovery of 100,000 Indiana bats.

Preliminary Observations of Habitat Use and Movements of the Eastern Massasauga Rattlesnake (Sistrurus c. catenatus)

We used radiotelemetry to monitor 12 eastern massasauga rattlesnakes, Sistrurus c. catenatus, within Bruce Peninsula National Park (Ontario) for 419 days. The snakes exhibited non-random use of habitat, strongly associating with wetlands and coniferous forest, and avoiding open areas (roads, trails), open water, and mixed forest. Hibernation sites also occurred in wetland and coniferous forest habitat. By contrast, snakes were disproportionately captured in open areas, presumably because they are much more easily detected there

Natural freeze tolerance in ectothermic vertebrates.

Amphibians and reptiles living in seasonally cold regions of the earth face several challenges to their continued survival. These include short summer seasons for the development of eggs and juveniles, long periods of fasting when food supplies are interrupted by winter, and months of cold exposure at environmental temperatures often well below the freezing point (FP) of their body fluids (21, 41, 64). This review focuses on one strategy of winter cold hardiness: freeze tolerance. A number of terrestrially-hibernating reptiles and amphibians have developed the ability to endure the freezing of extracellular body fluids and can revive after days or weeks spent with as much as 65% of their total body water locked in ice (41, 52, 61). All ectothermic vertebrates living in seasonally cold regions of the earth seek the shelter of thennally-buffered, relatively wann hibernacula. For most species, hibernation sites underwater or deep underground position the an­ imals to spend the winter without fear of freezing (21, 41, 64). Various species, however, hibernate at sites that are less well insulated; for example, several species of frogs hibernate on the forest floor. Here, coverings of leaf litter and snow insulate animals from the most extreme winter air tempera­ tures, but extended periods of subzero exposure, sometimes as low as -8°C, may occur (32, 35, 36). Species hibernating in such sites need additional

Effects of female body size and timing of nest foundation on the reproduction of the Japanese paper wasp, Polistes jadwigae Dalla Torre (Hymenoptera: Vespidae)

SummaryFemales in hibernation site (FH) were significantly larger than foundresses (FO), suggesting that larger FH were less successful in founding their nest. Body size of FO did not correlate with two nest characters, i.e., the number of cells at pupal stage (CP) and the timing of nest foundation (DP). However, CP negatively correlated with DP in 2 of 3 studied years, suggesting that foundress who founded her nest earlier than others tended to construct larger number of cells irrespective of her body size.

Hibernation in the Eastern Box Turtle, Terrapene c. carolina

Hibernation in the Eastern Box Turtle, Terrapene c. carolina

Overwintering and Spring Emergence of Three Coccinellid Species in the Coastal Plain of South Carolina

Overwintering sites and spring emergence periods of three commonly occurring coccinellids were studied from 1984 to 1989 in the upper coastal plain area of South Carolina. In addition, experiments were conducted to determine the influence of temperature and photoperiod upon the feeding activity of overwintering Hippodamia convergens (Guerin-Meneville) when removed from hibernation sites. Feeding activity began shortly after removal from hibernation, increased with increasing temperatures and continued during both the photoperiod and the scotoperiod. Broomsedge, Andropogon virginicum L., was found to be an important overwintering site for H. convergens. Coleomegilla maculata (De Geer) and Coccinella septempunctata L. often shared the same overwintering habitat. Spring emergence of all three species was found to be controlled by temperature and all species began emergence at ≈50DD accumulated degree-days, with the emergence period extending from about the first week of March to the middle of April. A tendency for directional flight upon emergence was shown by all three species, with significantly more H. convergens and C. septempunctata flying to the east and south sides of the emergence cages, which was with the prevailing winds during the emergence period.

Effects of incubation temperature on behavior of hatchling pine snakes: implications for reptilian distribution

Incubation temperatures in vertebrates affect incubation periods, and in some reptiles incubation temperature determines sex ratios and some limited behavior. Here I present evidence that incubation temperature in pine snakes (Pituophis melanoleucus) affects not only incubation periods and posthatching behavior in the laboratory, but also the behavior of hatchlings required for successful emergence and survival. These behavioral differences have evolutionary implications for selection of hatchlings from particular temperature nests. With increasing temperature, incubation periods decreased in the laboratory. In addition, incubation temperature affected hatching and emergence times as well as movement speed and foraging ability. Hatchlings from medium temperature conditions emerged from nests in the field in less time than hatchlings incubated at high or low temperatures, and hatchlings from low temperatures moved slower and were less able to capture and eat mice in the laboratory than hatchlings incubated at medium or high temperatures. Taken together, these laboratory and field experiments suggest that hatchlings from low temperature nests, compared to those from higher temperature nests, would be less able to emerge, find food, and locate hibernation sites prior to the onset of cold temperatures in the New Jersey Pine Barrens. These results suggest that incubation temperature affects a whole range of behavior and that distributional ranges of reptiles and other poikilotherms could be affected by summer temperatures (via incubation period and subsequent behavior) as well as ambient winter temperatures.

Effects of Temperature and Substrate on Survival and Lipid Consumption of Hibernating Coleomegilla maculata lengi (Coleoptera: Coccinellidae)

The influence of temperature and substrate quality on the hibernation of the polyphagous predator Coleomegilla maculata lengi Timberlake was examined. Survival rate and lipid content were periodically evaluated at six temperatures (20, 10, 4, −0.5, −4, and −10°C) on two substrates (fallen leaves and wood chips). Rapid total mortality was observed at −10, 10, and 20°C. At −4 and −0.5°C, survival extended until May, but only at −0.5°C was the survival rate higher than that observed at natural hibernation sites. Fallen leaves were a better substrate than wood chips except in situations of sudden warming and subsequent snow melt. The rate of lipid consumption increased with temperature, and no significant variation was found between substrates.

Northern Europe's most important bat hibernation site

In western Poland an underground fortification dating from the 1930s is the winter quarters for the largest aggregation of hibernating bats in northern Europe. Although a major threat has been averted, the bats remain vulnerable to disturbance. The author has been studying these animals since the mid-1970s and, with others, has been pressing for improved protection.

Trapping a local population of spruce bark beetles Ips typographus (L.): Population size and origin of trapped beetles

A method of trapping local populations of Ips typographus was investigated in the field. The size of a population emerging from a hibernation site in the forest litter was estimated using tent traps. This estimate was compared with another estimate where beetles from the population were marked and recaptured in pheromone traps. The estimate of population size with mark‐recapture was much higher than the estimate with tent traps, indicating a high degree of immigration. According to calculations only a minor part (less than 20%) of the beetles caught in the pipe traps originated in the local population. Re‐emerging parent‐adults were marked and released during the second flight period. The recapture rate was 29.8%, almost the same as during the first flight. Immigration during the first and second flight periods was estimated to be of similar magnitude. The results show that it is difficult to suppress local populations of highly mobile bark beetles by trapping.

Flight Behavior of Listronotus bonariensis (Coleoptera: Curculionidae) in the Waikato, New Zealand

The flight behavior of Listronotus bonariensis (Kuschel) in Waikato (New Zealand) pastures was studied by recording catches on aerial sticky traps and sampling ground populations; this was supported by dissection studies and laboratory experimentation. All flight activity in the field occurred between 25 August and 5 May. Flight phenology and intensity varied greatly between localities and years. Intensity was generally low, although occasional mass flights were observed. Sampled ground populations indicated that only a proportion of the weevils exhibited development of flight musculature and hence flight capability: the proportion of these “flight capable” weevils varied greatly from generation to generation. Field sampling and laboratory experimentation indicated partitioning of reproductive and dispersive effort among individuals in the population. Following emergence, some weevils became reproductive and others developed flight musculature before ovarian development and dispersal. The proportion of weevils in the latter category was highest in the field following peak emergence and was shown by laboratory experimentation to be increased by weevil crowding, particularly on unfavorable host plants. The laboratory experiments also indicated that alleviation of crowding resulted in degeneration of flight musculature and resumption of reproductive activity. Field sampling indicated overwintering in the pastures (summer breeding grounds) and no migration to adjacent potential hibernation sites. These results are discussed in relation to the climate of the Waikato and the dynamics of the populations.

Movements and hibernation sites of overwintering painted turtles in southern Ontario

Selection of hibernation sites and overwintering movements were examined in a small population of painted turtles (Chrysemys picta), in a pond near Lakefield, Ontario. Turtles emerged from overwintering sites where the water depth, sediment depth, and temperature did not differ from the average for the pond, but were less variable. Turtles overwintered in areas with water depths from 0.2 to 0.48 m, sediment depths from 0.5 to 0.95 m, and sediment temperatures from 3 to 6 °C. Contrary to prediction, turtles did not overwinter in the regions of the pond that were the first to melt in the spring. Four turtles tagged with temperature-sensitive transmitters and followed over the winter maintained carapace surface temperatures between 4 and 6 °C during the period of ice cover. Movements of turtles continued after ice cover but virtually ended once the water became anoxic. All turtles were buried in the mud from January to spring emergence in March.