Biology Flashcards
How many eggs does 1 female cedar borer lay per year? Choose the correct answer:
A) approximately 100
B) approximately 50
C) approximately 15
D) approximately 200
The correct answer is C: Adult females only lay around 15 eggs per season.
Given that the cedar borer is a stem pest and larva feed on heartwood of cedar and cypress, where would you expect adult females to lay eggs? Choose the correct answer:
A) In the upper crown of cedar or cypress trees on the branches.
B) Near the base of the tree and around the root collar.
C) On the leaders of cedar and cypress where bark is thin.
The correct answer is A: Females target the upper crown of cedar and cypress on branches where the bark is the thinnest. This allows the larva to penetrate the bark in order to access the heartwood in the upper stem of the tree, which is much closer to the surface than at the bottom or middle of the stem.
True or False question: As a coleopteran, the western cedar borer undergoes a hemimetabulous metamorphosis.
The answer is False: The Coleopteran order, including the cedar borer, undergo a holometabulous metamorphosis.
Choose the best answer that describes a holometabulous metamorphosis:
A) Egg hatches into larva - larva goes through a series of instars, growing in size each time before finally pupating - Pupa develops into adult form.
B) Egg hatches into larva - larva goes through a series of instars, growing each time, slowly taking on adult characteristics - final instar develops directly into adult.
The correct answer is A: Holometabulous metamorphosis is also referred to as a “complete” metamorphosis due to the obvious physical distinction between larva, pupa and adult. Hemimetabulous metamorphosis is more of a gradual change, where pupation is eliminated from the process and the larva slowly develops adult physical characteristics as it progresses through its instars. See the attached lifecycle diagram for the western cedar borer.
image source: https://sflonews.wordpress.com/2015/07/22/seeking-information-about-western-cedar-borer-a-significant-pest-of-western-red-cedar/
What do adult western cedar borers primarily feed on? Choose the best answer:
A) Foliage and new bark
B) New bark and flushing buds
C) Foliage
D) Heartwood and new bark
E) Heartwood
The correct answer is C: The adult feeds primarily on cedar foliage, causing minimal damage.
What do larval western cedar borers primarily feed on? Choose the best answer:
A) Sapwood
B) Sapwood and Heartwood
C) New Bark and Heartwood
D) Heartwood
The correct answer is D: Heartwood is the primary food source of the larval form. The lack of living defences in heartwood allows the larva to exist relatively free of the trees defence mechanisms once inside.
What life stage of powder worm is of greatest impact to the host? Choose the correct answer:
A) Adult
B) Larva
C) Pupa
The correct answer is B: The larval stage of Powder Worm causes the greatest amount of damage to the tree. The larva spends its entire existence inside the tree, boring into it and causing damage by feeding on the wood fibre. See attached image for an example of the damage.
image source: http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/32919.pdf
What time of year does the female adult cedar borer lay eggs? Choose the best answer:
A) March-April
B) May-June
C) June-July
D) April-May
The correct answer is B: May-June is the typical time of egg laying for this pest.
How does the cedar borer pupate?
The cedar borer forms a specialized pupal cell in the sapwood in the sapwood or near a branch scar.
How long does the pupa take to mature into an adult? What does the new adult do?
The pupa only takes 20 days to mature into an adult sometime between july and september. The new adult remains inside the cell over the winter, emerging in may-june of the following year. It will intermittently feed on cedar foliage for several days before mating. The attached image shows a young adult boring its way out of a pupal cell.
image source: http://web.forestry.ubc.ca/fetch21/Z-PDF-pest-info-folder/Trachykele%20blondeli.pdf
What conditions are suggested to have worsened powder worm damage in affected areas?
Weakened or stressed hosts due to decreased precipitation, previous logging and storms.
Based on the following image, describe the physical damage caused by cedar borer larva.
image source: http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/32919.pdf
The principal damage caused by this insect is the larval gallery bored in to the wood. The larva excavates its tunnel in the sapwood, but its goal is to reach the heartwood where it will complete the major portion of its gallery. It works either up or down the trunk and occasionally around it but follows the annual rings. Although the galleries always start in the crown of living trees they may end up in the crown or near the base of the tree. Attached is a photo depicting how shingle products are affected by the cedar borer.
image source: http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/32919.pdf
What is the reproductive adaptation that the cedar borer utilizes in order to make its eggs stay on the upper crown branches? Choose the best answer:
A) Creates silk with a specialized anal gland to stick eggs to tree.
B) Uses specialized mandibles to bore out egg sites and then covers them with a mixture of dung and frass.
C) Uses a specialized ovipositor to insert eggs into bark on branches in the crown.
D) Uses a specialized ovipositor to insert eggs into sapwood in branches on the crown where they are protected from predators.
The correct answer is C: The adult female targets the branches in the upper crown of redcedar, ovipositing eggs one at a time into bark crevices and folds.
Describe the cedar borer larva based on this 3x magnified photo:
image source: http://web.forestry.ubc.ca/fetch21/Z-PDF-pest-info-folder/Trachykele%20blondeli.pdf
A young larva is about 2.75 mm long and 1 mm wide across the thorax; a mature larva is 30-40 mm long and 6.8 mm wide. The small head is retracted into the broad flat thorax. The abdomen is much narrower than the thorax and consists of 10 subcylindrical segments. The larva is cream coloured except for dark brown mouth parts.
