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A small number of the forest species of lepidoptera (moths and butterf

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The Official Guide for GMAT Review, 2016

Practice Question
Question No.: RC 42 ~ 47
Page: 386

A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars Line during most of their life cycle) exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles. Although many different variables influence population levels, a regular pattern such as a population cycle seems to imply a dominant, driving force. Identification of that driving force, however, has proved surprisingly elusive despite considerable research. The common approach of studying causes of population cycles by measuring the mortality caused by different agents, such as predatory birds or parasites, has been unproductive in the case of lepidoptera. Moreover, population ecologists’ attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar populations have not succeeded. In short, the evidence implies that these insect populations, if not self-regulating, may at least be regulated by an agent more intimately connected with the insect than are predatory birds or parasites.

Recent work suggests that this agent may be a virus. For many years, viral disease had been reported in declining populations of caterpillars, but population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it. The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment. Nuclear polyhedrosis viruses are hypothesized to be the driving force behind population cycles in lepidoptera in part because the viruses themselves follow an infectious cycle in which, if protected from direct sun light, they may remain virulent for many years in the environment, embedded in durable crystals of polyhedrin protein. Once ingested by a caterpillar, the crystals dissolve, releasing the virus to infect the insect’s cells.Late in the course of the infection, millions of new virus particles are formed and enclosed in polyhedrin crystals. These crystals reenter the environment after the insect dies and decomposes, thus becoming available to infect other caterpillars.

One of the attractions of this hypothesis is its broad applicability. Remarkably, despite significant differences in habitat and behavior, many species of lepidoptera have population cycles of similar length, between eight and eleven years. Nuclear polyhedrosis viral infection is one factor these disparate species share.

Spoiler: :: OA
A

RC00120-06. It can be inferred from the passage that the mortality caused by agents such as predatory birds or parasites was measured in an attempt to

(A) develop an explanation for the existence of lepidoptera population cycles
(B) identify behavioral factors in lepidoptera that affect survival rates
(C) identify possible methods for controlling Lepidoptera population growth
(D) provide evidence that lepidoptera populations are self-regulating
(E) determine the life stages of lepidoptera at which mortality rates are highest


Spoiler: :: OA
C

RC00120-05.The primary purpose of the passage is to

(A) describe the development of new techniques that may help to determine the driving force behind population cycles in lepidoptera
(B) present evidence that refutes a particular theory about the driving force behind population cycles in lepidoptera
(C) present a hypothesis about the driving force behind population cycles in lepidoptera
(D) describe the fluctuating patterns of population cycles in Lepidoptera
(E) question the idea that a single driving force is behind population cycles in Lepidoptera


Spoiler: :: OA
D

RC00120-02 According to the passage, before the discovery of new techniques for detecting viral DNA, population ecologists believed that viral diseases--

(A) were not widely prevalent among insect populations generally
(B) affected only the caterpillar life stage of lepidoptera
(C) were the driving force behind Lepidoptera population cycles
(D) attacked already declining caterpillar populations
(E) infected birds and parasites that prey on various species of lepidoptera



RC00120-03. According to the passage, nuclear polyhedrosis viruses can remain virulent in the environment only when

(A) the polyhedrin protein crystals dissolve
(B) caterpillar population are in decline
(C) they are present in large numbers
(D) their concentration in a particular area remains low
(E) they are sheltered from direct sunlight



RC00120-04. It can be inferred from the passage that while inside its polyhedrin protein crystals, the nuclear polyhedrosis virus

(A) is exposed to direct sunlight
(B) is attractive to predators
(C) cannot infect caterpillars' cells
(D) cannot be ingested by caterpillars
(E) cannot be detected by new techniques of molecular biology


Spoiler: :: OA
B

RC00120-01. Which of the following, if true, would most weaken the author’s conclusion in lines 18-22?

(A) New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
(B) New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
(C) Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
(D) Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
(E) Viral disease is typically observed in a large proportion of the lepidoptera population.



JOURNAL ARTICLE
Population Outbreaks in Forest Lepidoptera
Judith H. Myers
American Scientist
Vol. 81, No. 3 (May-June 1993), pp. 240-251
Published by: Sigma Xi, The Scientific Research Honor Society
Stable URL: http://www.jstor.org/stable/29774919
Page Count: 12



OG 2019 ID's
RC00120-05
RC00120-06
RC00120-01
RC00120-02
RC00120-03
RC00120-04

Originally posted by icandy on 24 Feb 2009, 15:15.
Last edited by workout on 05 Sep 2018, 08:41, edited 13 times in total.
formatted, removed redundant question
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 25 Feb 2009, 09:12
...", population
ecologists’ attempts to alter cycles
by changing the caterpillars’ habitat
and by reducing caterpillar popula-
(25) tions have not succeeded....." hence B


icandy wrote:
A small number of the forest
species of lepidoptera (moths and
butterflies, which exist as caterpillars
Line during most of their life cycle) exhibit
(5) regularly recurring patterns of population
growth and decline—such
fluctuations in population are known
as population cycles. Although many
different variables influence popula-
(10) tion levels, a regular pattern such as
a population cycle seems to imply a
dominant, driving force. Identification
of that driving force, however, has
proved surprisingly elusive despite
(15) considerable research. The common
approach of studying causes of
population cycles by measuring the
mortality caused by different agents,
such as predatory birds or parasites,
(20) has been unproductive in the case of
lepidoptera. Moreover, population
ecologists’ attempts to alter cycles
by changing the caterpillars’ habitat
and by reducing caterpillar popula-
(25) tions have not succeeded. In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
(30) are predatory birds or parasites.
Recent work suggests that this
agent may be a virus. For many
years, viral disease had been
reported in declining populations
(35) of caterpillars, but population ecologists
had usually considered viral
disease to have contributed to the
decline once it was underway rather
than to have initiated it. The recent
(40) work has been made possible by
new techniques of molecular biology
that allow viral DNA to be detected
at low concentrations in the environment.
Nuclear polyhedrosis viruses
(45) are hypothesized to be the driving
force behind population cycles in
lepidoptera in part because the
viruses themselves follow an infectious
cycle in which, if protected from
(50) direct sun light, they may remain
virulent for many years in the environment,
embedded in durable
crystals of polyhedrin protein.
Once ingested by a caterpillar,
(55) the crystals dissolve, releasing
the virus to infect the insect’s cells.
Late in the course of the infection,
millions of new virus particles are
formed and enclosed in polyhedrin
(60) crystals. These crystals reenter the
environment after the insect dies and
decomposes, thus becoming available
to infect other caterpillars.
One of the attractions of this
(65) hypothesis is its broad applicability.
Remarkably, despite significant differences
in habitat and behavior, many
species of lepidoptera have population
cycles of similar length, between eight
(70) and eleven years. Nuclear polyhedrosis
viral infection is one factor these
disparate species share.

Which of the following, if true, would most weaken the author’s conclusion in lines 25-
30?
A. New research reveals that the number of species of birds and parasites that prey
on lepidoptera has dropped significantly in recent years.
B. New experiments in which the habitats of lepidoptera are altered in previously
untried ways result in the shortening of lepidoptera population cycles.
C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in
a number of predators and parasites of lepidoptera.
D. Differences among the habitats of lepidoptera species make it difficult to assess
the effects of weather on lepidoptera population cycles.
E. Viral disease is typically observed in a large proportion of the lepidoptera
population.

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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 25 Feb 2009, 09:52
Here is what I am confused about

25) tions have not succeeded. In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
(30) are predatory birds or parasites.

So what is the conclusion in these 5 lines?

Pop Cycles are not completely self regulated and not caused by birds or insects.

The fact that alteration cycles have not succeeded is an evidence

While I agree that B attacks the evidence, I dont think it weakens the conclusion one way or the other.

With C it is saying that the virus from predators/birds is actually the cause. So Pop cycles are possibly caused by virus by birds/predators. The later part of the passage clearly establishes that virus is transmitted by birds and predators.

So why is C wrong and B is correct? is it because the NPV is not introduced in the passage by the lines of 25-30??
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 25 Feb 2009, 10:04
I think it should be D.
A, C and E support the claim.
Between B and D, B tries to explain that it is the habitat and not the predator that regulates the population.

Hence, D.
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 25 Feb 2009, 14:35
3
icandy wrote:
Here is what I am confused about

25) tions have not succeeded. In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
(30) are predatory birds or parasites.

So what is the conclusion in these 5 lines?

Pop Cycles are not completely self regulated and not caused by birds or insects.

The fact that alteration cycles have not succeeded is an evidence

While I agree that B attacks the evidence, I dont think it weakens the conclusion one way or the other.

With C it is saying that the virus from predators/birds is actually the cause. So Pop cycles are possibly caused by virus by birds/predators. The later part of the passage clearly establishes that virus is transmitted by birds and predators.

So why is C wrong and B is correct? is it because the NPV is not introduced in the passage by the lines of 25-30??

25) tions have not succeeded. In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
(30) are predatory birds or parasites.

Which of the following, if true, would most weaken the author’s conclusion in lines 25-30?

--------------------------
Explanation:

A. New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years. ---> Irrelevant.

B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles. ---> The author mentions in the excerpt that there is some other agent that controls the insect population. He concludes this on the basis of info present in lines 15-25. But this option makes clear that there were still some untried ways, which actually resulted in some concrete findings (shortening of lepidoptera population cycles).

I think, nitya34 is also trying to convey the same reasoning.

C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera. ---> This may strengthen the argument by assuming virus as a more intimately connected regulatory agent. (Refer line 31: …..Recent work suggests that this agent may be a virus.....)

icandy: Can you please point to the line where it clearly establishes that virus is transmitted by birds and predators?

Anyways, IMO, even if it’s mentioned that the virus is transmitted by birds and predators, it’ll not be the correct answer because viruses are just piggybacking on birds and predators. Viruses are the actual agents not birds and predators.

So, I ruled out option C.

D. Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles. ---> Inconclusive. This option states that assessing the effect of weather (in case, it could have acted as an agent) on lepidoptera population cycles has proved to be a problematic task. As no results have been mentioned, we cannot conclude anything.

E. Viral disease is typically observed in a large proportion of the lepidoptera population. ---> Irrelevant.
--------------------------

I also go for option B.

Hope that helps.


Regards,
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 25 Feb 2009, 14:43
Technext wrote:
icandy wrote:
Here is what I am confused about

25) tions have not succeeded. In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
(30) are predatory birds or parasites.

So what is the conclusion in these 5 lines?

Pop Cycles are not completely self regulated and not caused by birds or insects.

The fact that alteration cycles have not succeeded is an evidence

While I agree that B attacks the evidence, I dont think it weakens the conclusion one way or the other.

With C it is saying that the virus from predators/birds is actually the cause. So Pop cycles are possibly caused by virus by birds/predators. The later part of the passage clearly establishes that virus is transmitted by birds and predators.

So why is C wrong and B is correct? is it because the NPV is not introduced in the passage by the lines of 25-30??

25) tions have not succeeded. In short,
the evidence implies that these insect
populations, if not self-regulating, may
at least be regulated by an agent more
intimately connected with the insect than
(30) are predatory birds or parasites.

Which of the following, if true, would most weaken the author’s conclusion in lines 25-30?

--------------------------
Explanation:

A. New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years. ---> Irrelevant.

B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles. ---> The author mentions in the excerpt that there is some other agent that controls the insect population. He concludes this on the basis of info present in lines 15-25. But this option makes clear that there were still some untried ways, which actually resulted in some concrete findings (shortening of lepidoptera population cycles).

I think, nitya34 is also trying to convey the same reasoning.

C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera. ---> This may strengthen the argument by assuming virus as a more intimately connected regulatory agent. (Refer line 31: …..Recent work suggests that this agent may be a virus.....)

icandy: Can you please point to the line where it clearly establishes that virus is transmitted by birds and predators?

Anyways, IMO, even if it’s mentioned that the virus is transmitted by birds and predators, it’ll not be the correct answer because viruses are just piggybacking on birds and predators. Viruses are the actual agents not birds and predators.

So, I ruled out option C.

D. Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles. ---> Inconclusive. This option states that assessing the effect of weather (in case, it could have acted as an agent) on lepidoptera population cycles has proved to be a problematic task. As no results have been mentioned, we cannot conclude anything.

E. Viral disease is typically observed in a large proportion of the lepidoptera population. ---> Irrelevant.
--------------------------

I also go for option B.

Hope that helps.


Regards,
Technext


Technext,

Thanks for pointing out my figment of imagination. Thats what happens when one does not pay attention to the detail or gets caught up in the Question too much. No where it is mentioned that birds/predators transmit it. It just says that virus has cycles too and they hide in the protein. So apparently C is wrong.

Now B makes more sense. because the author is deriving the conclusion based on the evidence in the paragraph, the same conclusion will be weakened if a counter evidence is found.

Thanks for the good discussion Technext.
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 31 Dec 2014, 00:33
PiyushK WaterFlowsUp Narenn dentobizz
This is an official question. kindly format this one.
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New post 02 Jan 2015, 10:17
WaterFlowsUp wrote:
PiyushK WaterFlowsUp Narenn dentobizz
This is an official question. kindly format this one.


Formatting done.But cant find the official answers
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 02 Jan 2015, 20:25
OA : BACD

Please delete this post after you including the OA
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 16 Mar 2015, 02:18
Nice and difficult passagee. BACD
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 24 Mar 2015, 02:53
what are the OA for this passage ? PiyushK , do you happen to have the official answers ?

took 8mins 40 secs.
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 13 Aug 2015, 17:50
questions 2:

I can't figure out why A is correct, could someone explain please?

I dont get why "develop an explanation for the existence..." is correct, i thought existence was confirmed and the scientists were looking for the agent that causes the population cycle?

BTW this question is now an OG16 new passage
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 17 Aug 2015, 12:10
Identification of the driving force has been surprisingly elusive. So, existence of population cycles is not proven. And in order to prove the existence the author gives the example of mortality caused by agents such as predatory birds or parasites. (as mentioned in Option A)

Hope this helps.
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 11 Oct 2015, 17:04
2
1. Which of the following, if true, would most weaken the author’s conclusion in lines 25- 30 (bold lines)?
The conclusion is the insect population maybe at least be regulated by an agent more intimate.... It is drawn based on 2 premises:
- The approach of measuring mortality caused by predatory birds or parasites does not work;
- The experiments to change caterpillar's habitat and population don't work either.

So in order to weaken the conclusion, we need to break the link between the conclusion and one of 2 above premises.

A. New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
Does not affect the conclusion. The number of those birds and parasites decreased, but the lepidoptera population fluctuated -> strengthen the conclusion.

B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
CORRECT! It is not that the experiments don't work, but the untried ones do -> the link between the conclusion and the 2nd premise is broken.

C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
Strengthen the conclusion when citing a possible cause related to the insect itself.

D. Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
This is a contender. I think it affects the conclusion on a certain level. Need someone's explanation for eliminating this choice.

E. Viral disease is typically observed in a large proportion of the lepidoptera population.
Same as C. It supports the conclusion.
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 17 Oct 2015, 22:57
can somebody explain q45
polpulation affected by intimate reasons than predators or parasites.
Environment affecting poplation is not a intimate reason and hence weakens the conclusion?
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New post 18 Oct 2015, 07:57
Everything correct except question 42.

One question thereto: I was between A) and C)

For me, the whole first half of the passage has nothing to do with C)
The presented, potential solution to explain the driving force behind the population cycles is a newly established method.

With this, how can I detect to choose C) in this case?

Can some expert throw light on this?

Lax
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 01 Nov 2015, 08:23
jojojoseph wrote:
can somebody explain q45
polpulation affected by intimate reasons than predators or parasites.
Environment affecting poplation is not a intimate reason and hence weakens the conclusion?


I think you should focus on the line : "...viral disease to have contributed to the decline once it was underway rather than to have initiated it". It means that viral disease is not the original cause of the generate the decline of lepidoptera. The decline happens ( " once it was under way"; "it" means the decline of lepidoptera) and then viral disease just adds its own distribution to that decline; viral disease is not the original cause of that decline.
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New post 28 Feb 2016, 11:31
I guess this is a new addition to the OG 16 Guide...Can someone explain question numbers 44 and 47?

44. Which of the following, if true, would most weaken the author’s conclusion in lines 25- 30 (bold lines)?

A. New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
D. Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
E. Viral disease is typically observed in a large proportion of the lepidoptera population.

It can be inferred from the bold lines that the insect populations (population cycles) is / are regulated by some other factor and not the ones mentioned in the first para (before the boldfaced portion). So, if we were to weaken this conclusion, what would be the best answer option?
I could easily eliminate options E, C and A and chose option D over B. Can someone help?

47.It can be inferred from the passage that while inside its polyhedrin protein crystals, the nuclear polyhedrosis virus

A. is exposed to direct sunlight
B. is attractive to predators
C. cannot infect caterpillars' cells
D. cannot be ingested by caterpillars
E. cannot be detected by new techniques of molecular biology

Well, I chose option D, which is wrong as it's explicitly mentioned in the passage that "Once ingested by a caterpillar, the crystals dissolve, releasing the virus to infect the insect’s cells" But I fail to understand why answer choice C is correct and how this option can be inferred. Looking forward to response from all you good people:)
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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 07 Jun 2016, 11:05
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A small number of the forest species of lepidoptera (moths and butterflies, which exist as caterpillars during most of their life cycle) exhibit regularly recurring patterns of population growth and decline—such fluctuations in population are known as population cycles. Although many different variables influence population levels, a regular pattern such as a population cycle seems to imply a dominant, driving force. Identification of that driving force, however, has proved surprisingly elusive despite considerable research. The common approach of studying causes of population cycles by measuring the mortality caused by different agents, such as predatory birds or parasites, has been unproductive in the case of lepidoptera. Moreover, population ecologists’ attempts to alter cycles by changing the caterpillars’ habitat and by reducing caterpillar populations have not succeeded. In short, the evidence implies that these insect populations, if not self-regulating, may at least be regulated by an agent more intimately connected with the insect than are predatory birds or parasites.

Recent work suggests that this agent may be a virus. For many years, viral disease had been reported in declining populations of caterpillars, but population ecologists had usually considered viral disease to have contributed to the decline once it was underway rather than to have initiated it. The recent work has been made possible by new techniques of molecular biology that allow viral DNA to be detected at low concentrations in the environment. Nuclear polyhedrosis viruses are hypothesized to be the driving force behind population cycles in lepidoptera in part because the viruses themselves follow an infectious cycle in which, if protected from direct sun light, they may remain virulent for many years in the environment, embedded in durable crystals of polyhedrin protein. Once ingested by a caterpillar, the crystals dissolve, releasing the virus to infect the insect’s cells. Late in the course of the infection,millions of new virus particles are formed and enclosed in polyhedrin crystals. These crystals reenter the environment after the insect dies and decomposes,thus becoming available to infect other caterpillars.

One of the attractions of this hypothesis is its broad applicability. Remarkably, despite significant differences in habitat and behavior, many species of lepidoptera have population cycles of similar length, between eight and eleven years. Nuclear polyhedrosis viral infection is one factor these disparate species share.

1. Which of the following, if true, would most weaken the
author’s conclusion in the highlighted text?

A. New research reveals that the number of species of birds and parasites that prey on lepidoptera has dropped significantly in recent years.
B. New experiments in which the habitats of lepidoptera are altered in previously untried ways result in the shortening of lepidoptera population cycles.
C. Recent experiments have revealed that the nuclear polyhedrosis virus is present in a number of predators and parasites of lepidoptera.
D. Differences among the habitats of lepidoptera species make it difficult to assess the effects of weather on lepidoptera population cycles.
E. Viral disease is typically observed in a large proportion of the Lepidoptera population.



2. It can be inferred from the passage that the mortality caused by agents such as predatory birds or parasites was measured in an attempt to

A. develop an explanation for the existence of lepidoptera population cycles
B. identify behavioral factors in lepidoptera that affect survival rates
C. identify possible methods for controlling lepidoptera population growth
D. provide evidence that lepidoptera populations are self-regulating
E. determine the life stages of lepidoptera at which mortality rates are highest



3. The primary purpose of the passage is to

A. describe the development of new techniques that may help to determine the driving force behind population cycles in lepidoptera
B. present evidence that refutes a particular theory about the driving force behind population cycles in lepidoptera
C. present a hypothesis about the driving force behind population cycles in lepidoptera
D. describe the fluctuating patterns of population cycles in Lepidoptera
E. question the idea that a single driving force is behind population cycles in lepidoptera



4. According to the passage, before the discovery of new techniques for detecting viral DNA, population ecologists believed that viral diseases

A. were not widely prevalent among insect populations generally
B. affected only the caterpillar life stage of lepidoptera
C. were the driving force behind lepidoptera population cycles
D. attacked already declining caterpillar populations
E. infected birds and parasites that prey on various species of lepidoptera



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Re: A small number of the forest species of lepidoptera (moths and butterf  [#permalink]

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New post 07 Jun 2016, 16:01
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Thanks souvik101990. Excited for this new project!!

3 right out of 4.

For 1st question, I was confused between B and C and chose the wrong answer.

My initial understanding was that the underlined portion talks about decline is population is not because of predatory birds or parasites but because of something that is intimately connected with the insect. So, was looking only for the option that refutes this premise. However, I missed 'in short' that also includes the previous line and hence opts out habitat as the reason of decline.

After few readings, I understood that option B weakens the underlined portion by giving an evidence of decline in population because of habitat change.
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Re: A small number of the forest species of lepidoptera (moths and butterf &nbs [#permalink] 07 Jun 2016, 16:01

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