The Biology and Behaviour of the European Pine Shoot Moth Rhyacionia buoliana (Schiff.), in Southern Ontario II. Egg, Larva, and Pupa

1963 ◽  
Vol 95 (8) ◽  
pp. 844-863 ◽  
Author(s):  
P. J. Pointing
Keyword(s):  
Small Groups ◽  
Ground Surface ◽  
Late Summer ◽  
Feeding Period ◽  
Tree Crown ◽  
Mortality Factors ◽  
Short Supply ◽  
Southern Ontario ◽  
Web Construction ◽  
Third Instar Larvae

AbstractThis is the second of two papers on this subject. The eggs of R. buoliana are usually found singly or in small groups on the hark or needle sheaths of new shoots, except under conditions of severe infestation where new foliage is in short supply. The first two instars feed on needles from within webs. Third-instar larvae mine one or more buds and cease feeding in late summer before the advent of unfavourable temperatures. Low temperature, lethal to overwintering third-instar larvae, is one of the most important and readily measured mortality factors, Larvae spin webs and moult before they resume feeding in April or May. Migration, usually upward in the tree crown, and web construction continue throughout the spring feeding period. Larvae within two feet of the ground surface on trees less than eight feet tall complete their development earlier than larvae at higher levels. Parasitism, based on previous extensive surveys, has very likely been underestimated.

Survey and control of small mammal populations on two hardwood plantations in southern Ontario

1974 ◽  
Vol 50 (5) ◽  
pp. 181-185 ◽  
Author(s):  
Andrew Radvanyi
Keyword(s):  
Small Mammal ◽  
Late Summer ◽  
Control Measures ◽  
Effective Control ◽  
Southern Ontario ◽  
Live Trapping ◽  
Surrounding Areas ◽  
And Control ◽  
Rodent Populations ◽  
Ingredient Cost

Live trapping and tagging methods were employed to assess small mammal populations within two hardwood plantations in southern Ontario. Excessive girdling damage in past years to young planted trees necessitated an evaluation of rodent populations and development of effective control measures. The application of an anticoagulant rodenticide to oat groats bait broadcast over the study area at an ingredient cost of approximately three dollars per acre virtually wiped out the small mammals. Reinvasion from surrounding areas was, however, fairly rapid, particularly during late summer. Further research on longer term control measures using poisoned bait feeder stations is recommended.

Lipid accumulation by migrating monarch butterflies (Danaus plexippus L.)

1993 ◽  
Vol 71 (1) ◽  
pp. 76-82 ◽  
Author(s):  
David L. Gibo ◽  
Jody A. McCurdy
Keyword(s):  
Lipid Accumulation ◽  
Seasonal Changes ◽  
Late Phase ◽  
Danaus Plexippus ◽  
Late Summer ◽  
Dry Mass ◽  
Middle Phase ◽  
Southern Ontario ◽  
Lipid Mass ◽  
Peak Abundance

The migration of Danaus plexippus during the late summer in southern Ontario in 1986 lasted for about 8 weeks and consisted of three phases, an early phase characterized by increasing abundance, a middle phase of peak abundance, and a late phase characterized by declining abundance. As the season progressed, systematic changes were observed in wet mass, dry mass, lean dry mass, lipid mass, and forewing length. Wet mass, lean dry mass, and forewing length were similar for early- and middle-phase individuals, but declined in late-phase migrants. Lipid mass peaked in the middle phase of the migration and then declined abruptly in the late phase. Dry mass also peaked in the middle phase, reflecting changes in lipid mass and lean dry mass. We hypothesize that the observed changes in lipid mass and lean dry mass over the 8 weeks resulted from changes in population structure as well as seasonal changes in the weather, and in availability of nectar. Opposing conclusions reached in previous studies of lipid accumulation in D. plexippus are probably the result of failure to control for phase of migration.

The life histories of north-temperate populations of the crayfish Cambarus robustus and Cambarus bartoni

1985 ◽  
Vol 63 (10) ◽  
pp. 2313-2322 ◽  
Author(s):  
Premysl Hamr ◽  
Michael Berrill
Keyword(s):  
Life History ◽  
Life Histories ◽  
Carapace Length ◽  
Late Summer ◽  
Temperate Climate ◽  
Free Living ◽  
Southern Ontario ◽  
The Third ◽  
Early Fall ◽  
First Time

The life histories of the crayfish Cambarus robustus and Cambarus bartoni were studied in the Kawartha Lakes region of southern Ontario. There were marked differences in their breeding and molting cycles compared with the familiar pattern of the Orconectes species of this region. Egg extrusion occurred later (July in C. robustus, June in C. bartoni), and juveniles therefore did not become free living until late summer or early fall. With little growing time in their first summer, they measured only 5–10 mm in carapace length (CPL) before growth ceased for the winter. At the end of their second summer the still immature crayfish measured 17–26 mm CPL in C. robustus and 13–20 mm CPL in C. bartoni. Maturity was therefore not attained until the end of the third summer, when most C. robustus matured at 34–45 mm CPL and C. bartoni at 25–30 mm CPL. The majority of individuals apparently reproduced for the first time during their fourth summer; a few apparently survived into another summer, reaching carapace lengths greater than 50 mm in C. robustus and 30 mm in C. bartoni. In males of both species, form 1 and form 2 occur throughout the summer. Although lacking the synchrony of Orconectes species, breeding and molting activities are still confined to the period between April and October. The timing of the life-history events observed in these two Cambarus species may be adaptations to seasonal stresses of the swift water environments that these species inhabit as well as to the relative harshness of the northern temperate climate.

Phenology and field biology of the dung beetle onitis caffer Boheman (Coleoptera: Scarabaeidae) in southern Africa

1986 ◽  
Vol 76 (3) ◽  
pp. 433-446 ◽  
Author(s):  
Penelope B. Edwards
Keyword(s):  
Late Summer ◽  
Summer Rainfall ◽  
Dung Beetle ◽  
Immature Stages ◽  
Average Depth ◽  
Winter Rainfall ◽  
The Third ◽  
Field Biology ◽  
June July ◽  
Third Instar Larvae

AbstractThe biology and development of immature stages of summer (SR) and winter rainfall (WR) strains of Onitis caffer Boheman were studied in South Africa in a summer rainfall area (Pretoria). A pair of adult beetles buried up to 650 ml of dung from one dung pad, and females laid an average of 1 egg for every 62 ml of dung buried. Broods were buried at an average depth of 50 cm in watered soil and 24 cm in unwatered soil. Eggs laid in June (winter) hatched 10 weeks later. The third instar was reached by late October. WR larvae suffered higher mortality (82%) with the onset of summer rains than did SR larvae (53%). By the following June, 6% of surviving WR individuals had emerged as adults, 12% were adults in faecal shells and 82% were diapausing third-instar larvae. Of the SR individuals, 67% emerged by June and 33% were diapausing third-instar larvae. In a second experiment, two groups of broods of the SR strain of O. caffer of different ages were set out in the field in June. One group, equivalent to broods produced early in the season (March), entered diapause as third-instar larvae, and adults emerged the following autumn. The second group represented broods produced later in the season (May); the majority did not diapause, but adults also emerged the following autumn. A field population of SR adults of O. caffer was sampled for two years. Adults were first recorded at the end of February (late summer), and newly-emerged specimens were caught up until the end of April. Maximum numbers were recorded in late March to early April (autumn), and activity ceased in June-July (winter).

Biotic mortality factors affecting emerald ash borer (Agrilus planipennis) are highly dependent on life stage and host tree crown condition

2015 ◽  
Vol 105 (5) ◽  
pp. 598-606 ◽  
Author(s):  
D.E. Jennings ◽  
J.J. Duan ◽  
P.M. Shrewsbury
Keyword(s):  
North America ◽  
Natural Enemies ◽  
Life Stage ◽  
Emerald Ash Borer ◽  
Agrilus Planipennis ◽  
Host Tree ◽  
Tree Crown ◽  
Crown Condition ◽  
Mortality Factors ◽  
Tree Resistance

AbstractEmerald ash borer (EAB), Agrilus planipennis, is a serious invasive forest pest in North America responsible for killing tens to hundreds of millions of ash trees since it was accidentally introduced in the 1990s. Although host-plant resistance and natural enemies are known to be important sources of mortality for EAB in Asia, less is known about the importance of different sources of mortality at recently colonized sites in the invaded range of EAB, and how these relate to host tree crown condition. To further our understanding of EAB population dynamics, we used a large-scale field experiment and life-table analyses to quantify the fates of EAB larvae and the relative importance of different biotic mortality factors at 12 recently colonized sites in Maryland. We found that the fates of larvae were highly dependent on EAB life stage and host tree crown condition. In relatively healthy trees (i.e., with a low EAB infestation) and for early instars, host tree resistance was the most important mortality factor. Conversely, in more unhealthy trees (i.e., with a moderate to high EAB infestation) and for later instars, parasitism and predation were the major sources of mortality. Life-table analyses also indicated how the lack of sufficient levels of host tree resistance and natural enemies contribute to rapid population growth of EAB at recently colonized sites. Our findings provide further evidence of the mechanisms by which EAB has been able to successfully establish and spread in North America.

scholarly journals Influence of diet on the morphology of the ruminal papillae in reindeer calves (Rangifer tarandus tarandus L.)

Rangifer ◽  
1996 ◽  
Vol 16 (3) ◽  
pp. 119 ◽  
Author(s):  
Terje D. Josefsen ◽  
Tove H. Aagnes ◽  
Svein D. Mathiesen
Keyword(s):  
Dry Matter ◽  
Rangifer Tarandus ◽  
Seasonal Pattern ◽  
Late Summer ◽  
Late Winter ◽  
Feeding Period ◽  
Cross Sectional ◽  
Sample Site ◽  
Different Seasons ◽  
Free Ranging

The influence of diet on the morphology of reindeer ruminal papillae was investigated in 4 groups of 3 free-ranging reindeer calves at different seasons, and in 11 groups of 3 reindeer calves fed experimental diets. Length, cross-sectional perimeter and density (number/cm2) of the ruminal papillae were measured in 4 sample sites in the rumen wall, and the ruminal surface enlargement factor (SEF) was calculated at each sample site. The range of group means were 2.3 to 3.4 mm for overall papillary length (mean of the four sample sites), 2.2 to 3.5 mm for overall cross-sectional perimeter, 85 to 189 papillae/cm2 for overall papillar density and 5.8 to 18.6 for overall SEF. Differences between sample sites wete observed, atrium ruminis having the highest and caudodorsal blind sac the lowest SEF (25% over and 24% below overall value, respectively). The differences between sample sites were considered to be small, indicating a homogenous ruminal content. The SEF of free-ranging animals showed a seasonal pattern, with high overall SEF (18.6) in September (late summer) and lower overall SEF {9.1) in April (late winter). Groups fed timothy silage with low content of cellulose (18.7% of dry matter) showed highest overall SEFs of the fed animals (17.8 and 13.9), while groups fed timothy silage with high content of cellulose (30.4%' of dry matter) showed lowest overall SEFs (5.8 and 7.0), indicating low ability to ferment silage with high content of cellulose. The SEF in animals fed experimental diets seemed partly to be influenced by SEF at the beginning of the feeding period.

Social-Behavior and Colony Formation in a Population of Crested Terns, Sterna-Bergii, in Southwestern Australia

1987 ◽  
Vol 14 (4) ◽  
pp. 529 ◽  
Author(s):  
JN Dunlop
Keyword(s):  
Social Behavior ◽  
Breeding Season ◽  
Small Groups ◽  
Social Behaviour ◽  
Colony Formation ◽  
Late Summer ◽  
Breeding Population ◽  
Southwestern Australia ◽  
Nest Sites ◽  
The Social

In a breeding population of crested terns near Fremantle, W.A., social behaviour involved complex patterns of social displays and paired behaviour. The social phase was probably truncated over much of the extended breeding season by the presence of incubating conspecifics, and may serve to synchronise laying in their absence. The responses of pre-laying crested terns to incubating conspecifics were studied by means of artificial 'colonies' of polyurethane models. These proved to be most attractive to prebreeding pairs searching for nest sites, and the earliest eggs were invariably laid among the decoys. Pre-breeding terns in the social phase were not attracted to the decoys. It is suggested that loose groups of incubating conspecifics acted as a key stimulus, releasing settlement and laying in birds in an advanced state of reproductive readiness. This key stimulus could change the learned location of colonies but during late summer and early autumn other factors, probably related to food availability, controlled the onset of laying. Small, spatially distinct, nesting groups were less synchronous in their laying than larger colonies. Such small groups are thought to result from discontinuities in reproductive phase between groups of terns, which are not apparent when the number of pre-laying birds is large.

A comparative study of the biology of five species of Neophylax (Trichoptera: Limnephilidae) in southern Ontario

1987 ◽  
Vol 65 (7) ◽  
pp. 1741-1754 ◽  
Author(s):  
B. D. Beam ◽  
G. B. Wiggins
Keyword(s):  
Life Cycle ◽  
Comparative Study ◽  
Late Summer ◽  
Larval Habitat ◽  
Temporal Development ◽  
Southern Ontario ◽  
Late Autumn ◽  
Organic Particles ◽  
Fine Organic ◽  
Stream Systems

The habitat, life cycle, behaviour, and food of five species of caddisflies of the genus Neophylax (N. aniqua Ross, N. ornatus Banks, N. concinnus McLachlan, N. oligius Ross, and N. fuscus Banks) were compared, based on general surveys and biweekly to monthly samples from several stream systems in southern Ontario. Larvae of four of the species, N. aniqua, N. concinnus, N. oligius, and N. fuscus, occur sequentially from the headwaters downstream and grow from late autumn through spring, but differ slightly in temporal development; adults of these species emerge in September and October, after a summer prepupal diapause. Larvae of the fifth species, N. ornatus, grow in late summer and autumn; their habitat coincides with portions of the habitats of N. aniqua and N. concinnus in cool headwater sections of streams, but adults emerge in June following a winter diapause. These species also differ in duration of diapause, case construction, location of pupal cases, and oviposition. All species graze on algae and fine organic particles from exposed surfaces of rocks. The study demonstrates that the five species of Neophylax studied differ in larval habitat and in time of development in ways that tend to keep them separate in stream systems. Evolutionary implications are considered.

scholarly journals Thermal remote sensing of ice-debris landforms using ASTER: an example from the Chilean Andes

2012 ◽  
Vol 6 (2) ◽  
pp. 367-382 ◽  
Author(s):  
A. Brenning ◽  
M. A. Peña ◽  
S. Long ◽  
A. Soliman
Keyword(s):  
Thermal Imaging ◽  
Land Surface ◽  
Ground Surface ◽  
Thermal Inertia ◽  
Thermal Conditions ◽  
Late Summer ◽  
Near Surface ◽  
Remote Sensors ◽  
Rock Glaciers

Abstract. Remote sensors face challenges in characterizing mountain permafrost and ground thermal conditions or mapping rock glaciers and debris-covered glaciers. We explore the potential of thermal imaging and in particular thermal inertia mapping in mountain cryospheric research, focusing on the relationships between ground surface temperatures and the presence of ice-debris landforms on one side and land surface temperature (LST) and apparent thermal inertia (ATI) on the other. In our case study we utilize ASTER daytime and nighttime imagery and in-situ measurements of near-surface ground temperature (NSGT) in the Mediterranean Andes during a snow-free and dry observation period in late summer. Spatial patterns of LST and NSGT were mostly consistent with each other both at daytime and at nighttime. Daytime LST over ice-debris landforms was decreased and ATI consequently increased compared to other debris surfaces under otherwise equal conditions, but NSGT showed contradictory results, which underlines the complexity and possible scale dependence of ATI in heterogeneous substrates with the presence of a thermal mismatch and a heat sink at depth. While our results demonstrate the utility of thermal imaging and ATI mapping in a mountain cryospheric context, further research is needed for a better interpretation of ATI patterns in complex thermophysical conditions.

Timing and causes of mortality in the endangered Vancouver Island marmot (Marmota vancouverensis)

2005 ◽  
Vol 83 (5) ◽  
pp. 674-682 ◽  
Author(s):  
Andrew A Bryant ◽  
Rick E Page
Keyword(s):  
Puma Concolor ◽  
Survival Rates ◽  
Late Summer ◽  
Vancouver Island ◽  
Winter Mortality ◽  
Mortality Factors ◽  
Proximate Cause ◽  
Island Endemic ◽  
Radio Transmitters ◽  
Probability Of Death

We used radiotelemetry to evaluate seasonal survival rates and mortality factors for a critically endangered island endemic, the Vancouver Island marmot (Marmota vancouverensis Swarth, 1911). Recovery of radio transmitters and marmot remains suggested that predation was the major cause of mortality, accounting for at least 24 of 29 (83%) known-fate deaths recorded since radiotelemetry efforts began in 1992. Wolves (Canis lupus L., 1758) and cougars (Puma concolor (L., 1771)) apparently accounted for 17 deaths (59%). Three marmots (10%) were killed by golden eagles (Aquila chrysaetos (L., 1758)), four (14%) were killed by unknown predators that probably included all of the above species, two (7%) died from unknown causes, and three (10%) died during hibernation in a single burrow. Mortality rates varied seasonally. The daily probability of death during hibernation was very low (Pdeath = 0.016). The probability of death was also low from spring emergence through 31 July (Pdeath = 0.051), but was eight times higher in August (Pdeath = 0.395) and four times higher in September (Pdeath = 0.175). We concluded that predation was the proximate cause of recent declines in wild Vancouver Island marmot populations, that losses were highly concentrated in late summer, and that previous studies exaggerated the importance of winter mortality. We suggest that high predation rates were associated with forestry and altered predator abundance and hunting patterns.

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