THE LIFE-HISTORY AND HABITS OF THE LARCH BARK BEETLE, IPS CEMBRAE (COLEOPTERA: SCOLYTIDAE), IN THE NORTH-EAST OF SCOTLAND

1970 ◽  
Vol 102 (2) ◽  
pp. 226-239 ◽  
Author(s):  
R. A. Balogun

AbstractAn investigation of the life-history and habits of Ips cembrae (Heer) has been made at the Ord wood, Cawdor Estate in Nairnshire. The species is polygamous and has a 1-year life cycle with two broods a year. The first broods result from eggs laid in May and June, producing teneral adults in August and September, and the second arise from egg-laying in late September and early October; these second broods generally overwinter under bark in the larval and pupal stages, and the adults emerge the following spring. There are three larval instars before pupation. Maturation feeding of the young beetles and regeneration feeding of the old ones take place either under the bark where broods have developed, or by attacking fresh host trees.

Author(s):  
Martin Sheader

A study was made of the life cycle and reproductive ecology of Gammarus duebeni in the Test Estuary on the south coast of England. The species is towards the southern limit of its distributional range in the north-east Atlantic, which results in breeding continuing throughout much of the year. The breeding strategy employed was found to vary with season. The size of eggs produced and the rate of egg production were both temperature dependent, whereas the proportion of production expended on eggs and the number of eggs per brood, although probably influenced by temperature appeared to be controlled by food availability and female size. Factors affecting the mortality of eggs within the marsupium and breeding synchrony were considered in relation to season. The life cycle consisted of two major overlapping generations.


1998 ◽  
Vol 130 (4) ◽  
pp. 387-397 ◽  
Author(s):  
David W. Langor ◽  
Daryl J.M. Williams

AbstractThe seasonal life history and mortality of the lodgepole terminal weevil, Pissodes terminalis Hopping (Coleoptera: Curculionidae), were investigated in young lodgepole pine, Pinus contorta Douglas var. latifolia Engelmann (Pinaceae), at three sites in west-central Alberta. Flight was monitored with traps. Development and mortality of all stages were investigated by dissecting infested leaders biweekly from late spring to early fall. Two years were required for P. terminalis to complete its life cycle, and generations overlapped. Overwintered adults emerged from the duff and commenced flight in late May, with a peak in mid-June. Eggs were present from mid-June to late July. There were four larval instars. The first two instars fed only in the phloem. Third and fourth larval instars eventually entered the pith to continue feeding, overwinter, and complete development the following spring. The new generation of adults emerged between mid-July and early August, fed on new shoots for several weeks, and overwintered in the duff. Adults have an obligatory diapause and did not reproduce until after winter. Fourth larval instars suffered the highest mortality. The major attributable cause of mortality was resinosis among eggs and young larvae and cold temperatures during the winter among mature larvae. Pathogens caused little mortality. Six species of parasitoids were collected.


Holzforschung ◽  
2002 ◽  
Vol 56 (4) ◽  
pp. 335-359 ◽  
Author(s):  
P. Oevering ◽  
A.J. Pitman

Summary Pselactus spadix attack of marine timbers was characterised by circular emergence holes 1.48±0.05 mm in diameter and adult tunnels (1.49±0.34 mm) breaking through the wood surface. Larval tunnels measured 0.407–1.892 mm in diameter, initiated from adult tunnels and increased in diameter away from the adult tunnel terminating in frass free pupal chambers (1.6±0.3 mm × 3.5±0.7 mm). Observations of larval tunnel locations indicated oviposition occurred inside the adult tunnels. P. spadix life history was investigated in Scots pine (Pinus sylvestris) heartwood at 22±2 °C and 99±1% r.h. Mean adult longevity was 11.5±6.5 months, with mean post-mating longevity for males (11.7±2.9 months) significantly longer than for females (6.3±1.1 months). Adults of at least 2–3 months old were found mating in galleries, which, with observations of the larval tunnel pattern, indicated P. spadix can complete its life cycle without emerging from wood. Five larval instars were identified by measurement of 1722 head capsule widths and application of Dyar's law. Mean development time from 2nd instar to adult emergence was 70.5±6.9 weeks and pupation took 14.6±5.8 days. Development from 2nd instar to reproductive adult took between 17–20 months, with life cycle approximating 24 months at 22±2 °C and 99±1%


2021 ◽  
Vol 15 (2) ◽  
pp. 209-2020
Author(s):  
Ruxandra Ionce ◽  
Iuliana Gabriela Breaban

LCA (Life Cycle Assessment) is a useful tool in decision-making for most businesses that opt for sustainability and offers the possibility to compare different products, processes, and value chain scenarios, both real and hypothetical. Coupled with S-ROI (Sustainable Return on Investment), the LCA has a great potential in using available data for existing mining sites in the North-East Region of Romania to assess the economic, social and environmental benefits of certain sustainability measures on a local and regional level. The article will explore this approach of combining the two methodologies: LCA (Life Cycle Assessment) and S-ROI (Sustainable Return on Investment), with necessary adjustments according to the characteristics of the local mining activities, to show key investment areas that can improve the value chain of copper exploitation and preparation in the mining perimeter Mănăila. The case of the copper mine in Mănăila offers a great opportunity to apply the current LICYMIN (Life Cycle of Mining) research and to use available Ecoinvent data for the copper ore by comparing the current value chain scenario with a proposed scenario that includes a different location for a mining ore preparation unit, closer to the quarry. The results will give an insight into the potential social and economic impact (the measure can translate into a higher local employment rate, better social stability, lower transportation costs, etc.) as well as the environmental impact (reduction of GHG emission, pollution, and energy efficiency) of the suggested changes.


1998 ◽  
Vol 130 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Peter de Groot

AbstractThe life history of the white pine cone borer, Eucosma tocullionana Heinrich, was studied from 1992 to 1994 in an eastern white pine seed orchard in Ontario. Adults flew from late May to early July, and egg laying commenced in mid-June. Oviposition coincided with the onset of white pine pollen release. Eggs were laid singly or in clusters on cones, with most of the eggs laid on the basal third of the cone. Head capsule measurements indicated five instars. Larvae fed in cones from mid-June to the end of August. Mature larvae exited the cones and dropped to the ground to pupate. The insect is univoltine. Parasitism by the Hymenoptera, Trichogramma and Apanteles, accounted for 5% of the eggs and 1% of the larvae, respectively. About 40% of the larvae died from being entrapped in resin. There were no significant differences in attack rates by E. tocullionana within the tree except in the middle level, where the south quadrant had significantly higher rates than the north quadrant.


2020 ◽  
Vol 7 ◽  
Author(s):  
Sinéad Murphy ◽  
Marie A. C. Petitguyot ◽  
Paul D. Jepson ◽  
Rob Deaville ◽  
Christina Lockyer ◽  
...  

Harbor porpoises exhibit early maturation, relatively short gestation/lactation periods and a faster rate of reproduction as compared to other cetacean species. Intrinsic and extrinsic factors can influence both population vital rates and population structure, which ultimately cause changes in dynamics within and between populations. Here, we undertook a retrospective analysis of mortality data collected over a 24-year period for assessing life history traits of the North-east Atlantic harbor porpoise population. We use time-period specific models for key life history relationships that considered cause of death of individuals (as a proxy for health status), sex and management unit (MU). Sexual variation in asymptotic length, asymptotic age, average length at 50% maturity (L50) and average age at 50% maturity (A50) were observed, with females attaining a larger asymptotic length, larger L50, and delaying attainment of both sexual and physical maturity, compared to males. While females are constrained in their minimum body size due to giving birth to proportionally larger offspring, males exhibited more plasticity in size at sexual maturity, enabling re-allocation of available energy resources toward reproduction. Data were then used to compare biological parameters among two porpoise MUs in United Kingdom waters, both of which in the current study exhibited reduced reproductive rates compared to other geographic regions. In both MUs, females significantly increased their A50 and males significantly declined in their L50. An increase in the age at asymptotic length was also observed in both sexes, along with a significant decline in the Gompertz growth rate parameter that was more apparent in the female data. While availability of suitable prey resources may be a limiting factor, a combination of other factors cannot be ruled out. Porpoises in the Celtic and Irish Seas MU were significantly larger in their maximum length, asymptotic length and L50 compared to porpoises in the North Sea MU throughout the study period, suggesting limited gene flow between these two MUs. These results justify the maintenance of these harbor porpoise MUs or assessment units, as two separate units, within the range of the North-east Atlantic population, and for indicator assessments under the EU’s Marine Strategy Framework Directive.


2006 ◽  
Vol 120 (3) ◽  
pp. 347 ◽  
Author(s):  
Laurie B. Marczak ◽  
John S. Richardson ◽  
Marie-Claire Classen

The life cycle of the dragonfly Cordulegaster dorsalis was studied over one year by systematic sampling of larvae in three intermittent headwater streams in southwestern British Columbia. We determined that larvae normally take three years to reach maturity, emerging throughout July and August. There is limited evidence suggesting a split cohort development, with early emergence after two years. Additionally, we tested whether larval instars were distributed randomly or if they occupied different sediment microhabitats. Smaller animals tend to be associated with smaller grained organic sediments, although there was high variation between the streams.


1936 ◽  
Vol 2 (2) ◽  
pp. 209-221 ◽  
Author(s):  
J. G. Rempel

In lakes of Saskatchewan adults emerge in late May and early June. Eggs, deposited over lake surface, sink to bottom. Larvae in soft bottom ooze (10–20 m. depth) grow rapidly in late summer, but little during rest of year. Four larval instars and two-year life-cycle. Larva and pupa described and additions made to Staeger's description of adult.


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