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145 Cards in this Set
- Front
- Back
- 3rd side (hint)
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______ is the pattern of growth from egg to adult
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ontogeny
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why is insect growth discontinuous, at least for the sclerotized cuticular parts of the body?
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because the rigid cuticle limits expansion.
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Size increase is by ______- The periodic formation of new cuticle of greater surface area, and subsequent _____, which is the shedding of the old cuticle.
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molting
ecdysis |
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For sclerite bearing body segments and appendages, increases in body dimensions are confined to _____ period immediately after _____, before the cuticle _______ & ______
sclerotized head capsule of a beetle or moth larva increases in dimensions in a ______ manner during development, whereas the membranous nature of body cuticle allows larval body to grow more or less _______. |
postmolt
molting stiffens and hardens saltatory manner ( in major increments) continuously |
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studies concerning development involve two components,
what are they? define them. |
1st component molt increment : is the increment in size occurring between one instar (growth stage) and the next
2nd component intermolt period: or interval, better known as the STADIUM or instar duration, which is defined as the time between successive ecdyses. |
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generally increase in size is measured as the increase in a single dimension (length or width) of some sclerotized body part, rather than a weight increment.
why is this? |
weight increment can be misleading because of variability in food and water intake
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The magnitude of both MOLT INCREMENTS AND INTERMOLT periods my be affected by ____, ____, _____, and ____, and may differ between the sexes of a species.
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food supply
temperature larval density physical damage |
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in _____, _____, and ______ insects growth is indeterminate: the animals continue to molt until they die.
There is no definitive terminal molt in such animals, so do these insects continue to increase in size throughout their adult life? |
collembolans, diplurans and apterygote insects
no; no definitive terminal molt but they don't continue to increase in size in their adult life |
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the vast majority of insects, growth is ______, as there is a distinctive instar that marks the cessation of growth and molting.
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determinate
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when do insets with determinate growth become reproductively mature?
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in final instar
called the adult or imaginal instar |
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a reproductively mature individual is called a adult or _____.
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imago
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in the imago or adult stage, for most insect orders it is ______, although secondary wing lost has occurred independently in the adults of several groups such as:
lice, fleas, and certain parasitic flies and in adult females of all scale insects (HEMIPTERA: coccoidea) |
fully winged
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what are the five major orders?
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Coleoptera: beetles
Diptera: flies Hymenoptera: wasps, ants, and bees Lepidoptera: butterflies and moths Hemiptera: bugs |
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In just one order of insects, the Ephemeroptera or MAYFLIES, a ______ immediately precedes the final or imaginal instar.
This ____ although capable of flight, only rarely is ______ |
subimaginal instar
subimago reproductive |
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in some pterygote taxa (winged insects) the total number of pre-adult growth stages or instars may vary within a species depending on environmental conditions, such as....(name three)
although in many other species, the total number of instars is determined ______ is constant regardless of environmental conditions |
developmental temperature
diet larva density genetically |
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growth is an important part of an individuals _____, the developmental history or that organism from egg to adult.
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ontogeny
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Changes in form (morphology) during ontogeny affect ____ & ____, but only external changes are apparent at each molt.
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external structures and internal organs
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we recognize three broad patterns of development morphological change during ontogeny, based of the degree of ______ that occurs in the ______phases of development.
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external alterations
post embryonic |
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the primitive developmental pattern, ______ is for the hatching to emerge from the egg in a form essentially resembling a miniature adult, lacking only____.
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genitalia
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This pattern is retained by the primitively wingless orders, the Archaeognatha (bristletails) and Zygentoma (silverfish) in which adults continue to molt after sexual maturity.
what is it? in contrast to, all ptergote (winged) insects that undergo more or less marked change in form, a ______, between the immature phase of development and the winged or secondarily (apterous) adult or imaginal phase. |
ametaboly
metamorphosis |
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All ptergote insects undergo a more or less marked change in form, a metamorphosis, these insects can be subdivided according to two broad patterns of development _______, and ________. (define both)
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hemimetaboly: partial or incomplete metamorphosis
holometaboly: complete metamorphosis |
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developing wings are visable in external sheaths on the dorsal surface of nymphs of _______ insects except in the youngest immature instars.
The term ______ has been applied to this type of "external" wing growth. |
hemimetabolous
exopterygote |
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pterygote orders displaying holometabolous development share the unique evolutionary innovation of a resting stage or _____ in which development of the major structural differences between immature (larval) and adult stages is is concentrated.
the orders that share this unique, derived pattern of development represent a clade called the Endopterygota or _______. |
pupal instar
Holometabola |
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in many holometabola, expression of all adult features is retarted untill the _____
however in Drosophila uniquely adult structures including wings may be present internally in larvae as groups of undifferentiated cells called ______, although they may be scarcely visible untill the pupal instar. such wing development is called ______because the wings develop from primordia in invaginated pockets of the integument and are everted only at the larval-pupal molt. |
pupal stage
imaginal discs (or buds) endopterygote |
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what does the evolution of holometaboly allow the immature and adult stages of an insect to do?
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specialize in different resources, contributing to the successful radiation of the group
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Embryonic Stage
when does the egg stage begin? |
as soon as the female deposits the mature egg.
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Embryonic Stage
the age of an egg is estimated from the time of its _____, even though the egg existed before oviposition. |
deposition
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Embryonic Stage
when does the individual insect ontogeny begin? |
when the embryonic development within the egg is triggered by ACTIVATION
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Embryonic Stage
and insects ontogeny begins when embryonic development within the egg is triggered by activation. this trigger results from what two things (or ways) |
1) fertilization in sexually reproducing insects
2)in parthenogenetic species appears to be induced by various events at oviposition, including the entry of oxygen to the egg or mechanical distortion |
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following the activation of the insect egg cell, the zygote nucleus subdivides by mitotic division to produce many daughter nuclei, giving rise to a _____.
These nuclei and their surrounding cytoplasm, called cleavage ______, migrate to the egg periphery where the membrane infolds leading to cellularization of the superficial layer to form the one-cell thick _____. This distinctive superficial cleavage during early embryogenesis in insects is the result of the large amount of ____ in the egg. the blastoderm usually gives rise to ____ whereas the central yolky part of the egg provides _____ and will be used up by the time of ____, or emergance from the egg |
syncytium
energids yolk to all the cells of the larva body the nutrition for the developing embryo ECLOSION blastoderm |
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Embryonic Phase
Regional differentiation of the blastoderm leads to the formation of the germ ____ or germ disk, which is the first sign of the developing embryo, whereas the remainder of the blastoderm becomes a thin membrane, the _____, or embryonic cover. |
anlage-germ disk
serosa embryonic cover |
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Embryonic Phase
the germ anlage develops an infolding in the process called ______ and sinks into the yolk, forming a two layered embryo containing the amniotic cavity. After gastrulation, the germ anlage becomes the ______, which externally is characterized by segmental organization. |
gastrulation
germ band |
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The germ band forms _____ regions of the future body, which progressively differentiates with the ___, ____, and ____becoming increasingly well defined.
At this time the embryo undergoes movement called the _______, which brings it into its final position in the egg later, near the end of embryogenesis, the edges of the germ band grow over the remaining yold and fuse mid-dorsally to form the lateral and dorsal parts of the insect: a process called ________. |
ventral
head body and appendages katatrepsis dorsal closure |
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Embryonic Phase
In the well studied Drosophila, the complete embryo is large, and becomes segmented at the cellularization stage, termed "_____". In contrast, in "_____" insects the embryo derives from only a small region of the blastoderm and the posterior segments are added ________, during subsequent growth. In the developing long-germ embryo, the syncytial phase is followed by cell membrane intrusion to form the _________phase |
long germ
short germ post cellularization blastoderm |
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Embryonic Phase
functional specialization of cells and tissues occurs during the latter period of embryonic development , so that by the time of hatching the embryo is a tiny proto insect packed into an eggshell. in ametabolous and hemimetabolous insects, this stage may be recognized as a ______: a special hatching stage |
pronymph
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Larval or nymphal phase
Hatching from the egg may be by a ___, _____, or ____: eclosion conventionally marks the beginning of the _______, when the young insect is said to by in its first instar. This stage ends at the first _____ when the old cuticle is cast to reveal the insect in its second instar. Third and often subsequent instars generally follow. |
pronymph nymph or larva
first stadium ecdysis |
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The development of the immature insect is characterized by repeated molts separated by period of feeding, with _______insects generally undergoing more molts to reach adulthood than _____insects
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hemimetabolous
holometabolous |
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Larval or nymphal phase
all immature holometabolous insects are called ____. Immature terrestrial insects with hemimetabolous development such as ____,___,___, and ____ always are called nymphs. |
cockroaches (Blattodea)
grasshoppers (Orthoptera) mantids (Mantodea) bugs (Hemiptera) |
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True ____ look very different from the final adult form in every instar, whereas ____ more closely approach the adult appearance at each successive molt.
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larvae
nymphs |
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_____ diets and lifestyles are very different from those of their adults. In contrast, ____often eat the same food and coexist with the adults of their species.
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larval
nymphs |
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Competition is rare between ______but is likely to be prevalent between _____.
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larvae and their adults
nymphs and their adults |
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the great variety of endopterygote larvae can be classified into a few functional rather than phylogenetic types. Ofter the same larval type occurs convergenly in unrelated orders.
what are the three commonest forms ? |
polypod
oligopod apod larvae |
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lepidopteran caterpillars with cylindrical bodies with short thoracic legs and abdominal prolegs are characteristic of what type of larvae?
symphytan hymenoptera and most mecoptera are also this kind of larvae. such larvae are rather INACTIVE and are mostly phytophagous. |
polypod larvae
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given the following characteristics, which larvae consists of these
-lack of abdominal prolegs but have functional thoracic legs and frequenly prognathous mouthparts -active predators but others are slow moving detritivores living in soil or are phytophages. -this larval type occurs in at least some members of most orders of insects but not in lepidoptera, mecoptera, siphonaptera, diptera or strepsiptera |
oligopod larvae
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which larval type consists of these characteristics
-lack true legs, are worm like or maggot like -live in soil, mud, dung, decaying plant or animal matter, or within the bodies of other organisms as parasitoids -siphonaptera, aculeate hymenoptera, nematoceran diptera and many coleoptera typically have this larval type with a well developed head. |
apod larvae
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what is a major change in form during the larval phase,(such as different larval types in different instars) called?
In the Strepsiptera and certain beetles this involves an active first instar larva, or _______, followed by several grub like, inactive, sometimes legless, later instar larvae. this is typical of what kind of insect |
larval heteromorphosis or (hyper metamorphosis)
triungulin parasitic wasps |
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all pterygote insects undergo varying degrees of transformation from the immature to the adult phase of their lift history.
which type of insects show only slight morphological changes during postembryonic development? give and example insect of this type which is the type where the body is largely reconstructed at metamorphosis. |
exopterygotes -
example cockroaches endopterygotes |
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only orders belonging to the ______have a metamorphosis involving a pupal stadium, during which adult structures are elaborated from certain larval structures and from imaginal discs.
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Holometabola (=Endopterygota)
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in some holometabolous insects, such as Drosophila, most larval tissues are destroyed at ______ and the pupal and adult structures are formed largely from ____ ___.
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metamorphosis
imaginal discs |
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alterations in body shape, which are the essence of metamorphosis, are brought about by what?
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differential growth of various body parts.
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organs that will function in the adult but that were undeveloped in the larva grow at a _____rate
the accelerated growth of ____ is the most obvious example but ___, ___,___, and other internal organs may increase in size and complexity to a considerable extent. |
at a faster rate than the body average
wing pads legs genitalia gonads |
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what is the trigger for onset of metamorphosis?
what occurs? |
-attainment of a certain body size (Critical mass)
-which programs the brain for metamorphosis by altering hormone levels |
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the molt into the pupal instar is called _____or _____
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pupation or
larval pupal molt |
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many insects survive conditions unfavorable for development in the "resting" , ____ ____stage.
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non feeding pupal stage
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often what appears to be a pupa is actually a fully developed adult within the pupal cuticle
what is this referred to as |
pharate (cloaked) adult
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typically, a protective CELL or COCOON surrounds the pupa and then, prior to emergence, the pharate adult
which four orders have an "unprotected" pupae |
1. Coleoptera
2. Diptera 3. Lepidoptera 4. Hymenoptera |
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what kind of pupae have their appendages
-legs -wings -mouthparts -and antennae not closely appressed to the body |
exarate
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what kind of exarate pupae can have articulated mandibles that the pharate adult uses to cut through the cocoon
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decticous
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which kind of exarate pupae can have mandibles non articulated ?
how do these type of pupa escape the cell or cocoon? |
adecticous
adult usually first sheds the pupal cuticle and then uses its mandibles and legs to escape the cocoon or cell |
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what kind of pupae have their appendages cemented to the body and the cuticle is ofter sclerotized
as in almost all ______ |
obtect
lepidoptera |
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In some cyclorrhaphous Diptera (the Schizophora) the adecticous exarate papa is enclosed in a ______: the sclerotized cuticle of the last larval instar
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puparium
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escape from the puparium is facilitated by eversion of a membranous sac on the head of the emerging adult, the ______.
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ptilinum
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insects with a ____pupae lack a cocoon
what are examples of these? |
obtect
coccinellid beetles nematocerous orthorrhaphous Diptera |
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if a cocoon is present , as in most lepidoptera, emergence from the cocoon is by what 3 possible ways
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1. using backwardly directed abdominal spines
2. projection of head 3. an adult emerges from the pupal cuticle before escaping the cocoon, sometimes helped by a fluid that dissolves the silk |
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except for ______ insects do not molt again once the adult phase is reached
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mayflies
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the adult or imaginal stage has a reproductive role and is ofter the _____ stage in insects with sedentary larvae
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dispersive
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when is the image that emerges (ecloses) from the cuticle of the previous instar capable of reproduction
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almost immediately
or a period of maturation may precede sperm transfer or oviposition |
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the amount of reproductive cycles in the adult stadium (ranging from one to several) depends of on what two things
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1 species
2 food availability |
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the adult of certain species are very short lived and have
-reduced or no mouthparts -fly for only a few hours or at the most a day or two -they simple mate and die name three species like this |
mayflies
midges male scale insects |
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how long do most insects live ?
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at least a few weeks, ofter a few mouths, and sometimes for several years
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what kind of insects are particularly long lived?
name three |
1 termite reproductives
2 queen ants 3 bees |
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what is associated with a 100 fold increase in adult lifespan, based on a comparison of the mean average longevity of ANT TERMITE AND HONEY BEE QUEENS with that of adult solitary insects from eight orders.
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eusociality
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when does adult life begin?
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at eclosion from the pupal cuticle
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true of false
adult life and metamorphosis begins at eclosion from the pupal cuticle |
false
adult life does begin at eclosion from the pupal cuticle but metamorphosis may have been complete for some hours, or weeks previously and the pharate adult may have rested within the pupal cuticle until the appropriate _______trigger for emergence |
environmental
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what are 3 possible triggers of synchronized adult emergence in most species
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1. changes in temperature
2 changes in light 3 chemical signals |
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hormonal control of emergence has been studied most comprehensively in ________, especially in the _______
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lepidoptera
tobacco hornworm Manduca sexta |
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the description of the following events at ecosion are based largely on ______
at least __ hormones are involved in eclosion a few day prior to eclosion the _____level declines, and a series of physiological and behavioral events are initiated in preparation for _____, including the release of two neuropeptides ___ & ___ where are these two released from these two act in concert to trigger ____ behavior |
manduca sexta
5 ecdysteriod ecdysis ecdysis triggering hormone (ETH): from epitracheal glands called Inka cells eclosion hormone (EH) : from neurosecretory cells in the brain, pre-eclosion |
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ETH is released first and and ETH and EH stimulate each other's release, forming a ________.
the build up of EH also releases ______ from cells in the ____. CCAP switches off ____behavior and switches on _____behavior |
positive feedback loop
crustacean cardioactive peptide (ccap) preclusion behavior eclosion behavior |
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eclosion behavior includes what 3 possible behaviors after CCAP switches it on?
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1. wing base movements
2. accelerates heart beat 3. abdominal contraction |
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EH appears to permit release of further neurohormones __ & __
these two are involved in wind expansion after ecdysis |
bursicon and cardiopeptides
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name the neurohormone that stimulates the heart, facilitating movement of hemolymph into the thorax and thus into the wings?
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cardiopeptides
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the Bursicon neurohormone induces a brief increase in cuticle plasticity that allows wing expansion, this is followed by what?
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sclerotization of the cuticle in its expanded form
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the newly emerged, or _____, adult has soft cuticle, allowing expansion of the body surface by three ways
which are these |
teneral
1. by swallowing air 2 by taking air into the tracheal sacs 3 and by locally increasing hemolymph pressure by muscular activity |
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the wings normally hand down which aids ______
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inflation
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when does pigment deposition in the cuticle and epidermal cells occur?
and is either linked to, or followed by, sclerotization of the body cuticle under the influence of which neurohormone |
just before or after emergence
bursicon |
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following emergence from the pupal cuticle , many holometabolous insects void a fecal fluid called the _____
this represent metobolic wastes that have accumulated during the ____. sometimes the teneral adult retains the ____ in the rectum until sclerotization is complete, thus aiding _____ |
meconium
pupal stadium meconium increase in body size |
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_____ is the main function of adult life and the length of the _____, at least in the female, is related to the duration of egg production.
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reproduction
imaginal stadium |
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____correlates with termination of reproduction, and death may be predetermined in the ___ of an insect.
when do females die when do males die |
senescence
ontogeny females may die after egg deposition and males may die after mating |
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why is an extended post reproductive life important in distasteful, aposematic insects
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allows predators to learn distastefulness from expendable prey individuals
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how is a instar defined
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extending from ecdysis to ecdysis
(since shedding of the old cuticle is an obvious event) |
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in terms of morphology and physiology, a new instar comes into existence at the time of _____ when the epidermis separates from the cuticle of the previous stage.
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apolysis
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why do insect survive adverse conditions as pharate pupae or pharate adults?
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because in this state the double cuticular layer restricts water loss during a developmental period during which metabolism is reduced and requirements for gaseous exchange are minimal
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molting is a complex process involving 4 changes that lead up to the shedding of the old cuticle.
which are these four types of changes? |
1. hormonal
2. behavioral 3. epidermal 4. cuticular |
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which kind of cells are actively involved in molting?
what are they responsible for? |
epidermal cells
they are responsible for partial breakdown of the old cuticle and formation of the new cuticle. |
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when does the molt commence?
why is the separation incomplete? |
with the retraction of the epidermal cells from the inner surface of the old cuticle
because muscles and sensory nerves do retain connection with the old cuticle |
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_____ either is correlated with or followed by mitotic division of the epidermal cells.
what does this lead to? |
apolysis
leading to increases in the volume and surface area of the epidermis |
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The subcuticular or _______ formed after apolysis fills with the secreted but inactive molting fluid.
when are CHITINOLYTIC AND PROTEOLYTIC enzymes of the molting fluid activated? |
apolysial space
after the epidermal cells have laid down the protective outer layer of the new cuticle. |
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The subcuticular or _______ formed after apolysis fills with the secreted but inactive molting fluid.
when are CHITINOLYTIC AND PROTEOLYTIC enzymes of the molting fluid activated? |
apolysial space
after the epidermal cells have laid down the protective outer layer of the new cuticle. |
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during molting what happens to the inner part of the old cuticle (endocuticle) ?
what happens to the new pharate cuticle? |
endocuticle is lysed and presumable resorbed
while the new pharate cuticle continues to be deposited as an undifferentiated procuticle. |
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_____commences with the remnants of the old cuticle splitting along the dorsal midline as a result of increase in hemolymph pressure.
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ecdysis
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the cast of the cuticle consists consists of three things
what are they? |
1. indigestible protein
2. lipid 3. and chitin of the old epicuticle and exocuticle |
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once free of the constrains of the previous "skin" the newly ecdysed insect expands the new cuticle.
what are two ways in which this is achieved? |
1. swallowing air or water
2. by increasing hemolymph pressure in different body parts to smooth out the wrinkled and folded epicuticle and stretch the procuticle. |
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after cuticular expansion, some or much of the body surface may become sclerotized by the chemical stiffening and darkening of the procuticle to form __________.
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exocuticle
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in larval insects most of the body cuticle remains ______ and the ____is confined to the head capsule
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membranous
exocuticle |
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following ecdysis, more proteins and chitin are secreted from the epidermal cells, thus added to the inner part of the procuticle, the endocuticle, which may continue to be deposited well into the ______period.
sometimes the ____is partially sclerorized during the stadium and frequently the outer surface of the cuticle is covered in _______. finally the stadium draws to an end and ___is initiated once again |
intermolt
endocuticle wax secretions apolysis |
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hormonal regulation of molting has been studied most thoroughly at metamorphosis, when endocrine influences on molting per se are difficult to separate from ...
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those involved in the control of morphological change.
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what are the three major types of hormones controlling molting and metamorphosis?
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1. neuropeptides, including prothoracicotropic hormone PTTH, ecdysis triggering hormone ETH and eclosion hormone EH
2. ecdysteroids 3. juvenile hormone JH which may result in several different form even in the same insect |
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Neurosecretory cells in the brain secrete ___which passes down the nerve axons to the ____ ____ , a pair of neuroglandular that bodies that store and later release ____ into the hemolymph.
The PTTH initiates each molt by stimulating _______ synthesis and secretion by the _______ or molting glands. ________ release then initiates the changes in the epidermal cells that lead to the production of new cuticle. |
PTTH
corpora cardiaca PTTH ecdysteriod prothoracic ecdysteriod |
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The characteristics of the molt are regulated by ___ from the corpora allata.
____ inhibits the expression of adult features so that a high hemolymph level (titer) of ___ is associated with a ______molt, and a lower titer with a ______molt, |
JH
JH JH larval larval molt larval pupal molt |
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JH is absent in the ___ ____ molt
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pupal adult molt
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ecdysis is mediated by ___ &___
and ____at least appears to be important at every molt in the life history of all studied insects |
ETH
EH |
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This neuropeptide acts on a steroid primed central nervous system to evoke the co-ordinated motor activities associated with escape from the old cuticle.
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EH
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___drives its name from the pupal-adult ecdysis, or eclosion.
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EH
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the association of EH with molting appears to be ancient, as _____ have EH homologous
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crustaceans
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In well studied tobacco horn worm Manduca sexta, the more recently discovered ETH is as important to ecdysis as EH, with ETH doing what two things?
in other insects, another neuropeptide, _____, controls sclerotization of the exocuticle and post molt deposition of endocuticle |
1. initiating the pre-ecdysis behavior that loosens muscle attachments from the old cuticle
2. causing the release of EH from the brain. bursicon |
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a correlation exists between the _______&___________that occur in the last two larval instars and in prepupal development
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the ecdysteroid and JH jitters and the cuticular changes
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During the molt at the end of the fourth larval instar, how does the epidermis respond to the surge of ecdysteroid?
A new cuticle is synthesized, much of the old cuticle is digested, and production of __&____resumes by the time of ecdysis. In the final, fifth larval instar (but not the previous instars), ___inhibits the secretion of PTTH and ecdysteroids, and thus the level of ___ must decline to zero before the ecdysteroid level can rise. |
by halting synthesis of endocuticle and the blue pigment insecticyanin
endocuticle and insecticyanin JH JH |
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when ecdysteroid initiates the next molt, the epidermal cell produce a stiffer cuticle with thinner lamellae (the pupal cuticle) as a result of the activation of _____
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many new genes
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what does the decline of ecdysteroid level towards the end of each molt seem to be essential for?
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(and may be a physiological trigger causing ecdysis) to occur.
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a cascade of small hormones is released after the new cuticle has formed and the ecdysteroid titer has dropped below _________
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a threshold level
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what (at the end of the fifth larval instar) marks the beginning of a prepupal period when the developing pupa is pharate within the larval cuticle.
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Apolysis
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during larval life, what do epidermal cells covering most of the body NOT produce?
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exocuticle
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the caterpillar's soft and flexible cuticle allows the considerable growth seen within an instar, especially the last larval instar, as a result of what?
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voracious feeding
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In the tobacco hormworm
what does onset metamorphosis involve? what causes the the reduction (to zero) in the amount of circulating JH (2 things) who does reduction of JH initiate? when does growth cease? what occurs after photoperiod "gate" opens? |
-attainment of critical mass by the final instar larva -
1. reduced corpora allata activity 2. and enzymatic degradation of JH in the hemolymph a subsequent cessation of feeding caused by ecdysteroid levels growth does not cease immediately that the critical mass is attained, but continues untill sometime during the next 24 hours afters JH levels reach zero, when a photoperiod "gate" opens PTTH is expressed, triggering the burst of ecdysteroid ( as ecdysone) that stimulates behavioral changes and induces commencement of a molt to pupal development |
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what does the final body size at metamorphosis depend on?
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how much feeding (and growth) takes place between attainment of the critical mass
& the delayed onset of PTTH secretion, and ultimately adult size |
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insects are short live creatures, whose lives can be measured by __________:
the number of generations per year most insects take __________to develop, with either one generation per year _________ or __________ or more than two_________ generation times in excess of 1 year are called ________ |
voltinism
a year or less univoltine bivoltine multivoltine or polyvoltine semivoltine |
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give two possible explanations for why there are insects that have generation times in excess of a year (semivoltine)
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1. amongst some inhabitants of the polar extremes, where suitable conditions for development may exist for only a few week in each year.
2. large insects that rely upon nutritionally poor diets also develop slowly over many years |
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____ _____feeding on sap from tree roots may take either 13 to 17 years to mature, and beetles that develop with dead wood have been known to emerge after more than ___ years' development
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periodic cicadas
20 |
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how come insects do not develop continuously throughout the year?
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they arrest their development during undesirable times by quiescence or diapause
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many univoltine and some bivoltine species enter _____ at some stage, awaiting suitable conditions before completing their life cycle.
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diapause
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for which type of insect can adult longevity extend to several years?
for which type of insect can life be as little as a single evening? or even a few hours at the low tide? |
for some univoltine insects, many social insects, and others that take longer than a year to develop
multivoltine - Ephemeroptera -marine midges such as Clunio |
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Describe the general size of multivoltine insects, their general time of development and the distribution of the resources they use
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-tend to be small
-fast developing -use resources that are more evenly available throughout the year. |
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______is common amongst temperate insects, particularly those that use resources that are seasonally restricted.
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univoltinism
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give 2 examples of univoltine insects
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1. insects whose aquatic immature stages rely on spring algal bloom
2. or phytophagous insects using shortlived annual plants. |
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_______insects include those that develop slowly on evenly spread resources, and those that track a bimodally distributed factor, such a spring and fall temperature.
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bivoltine
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some species have fixed voltinism patterns, whereas other may vary with geography, particularly in insects with broad ____or _____
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latitudinal or elevational ranges
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The developmental progression from egg to adult often is interrupted by a period of dormancy.
describe the characteristic environmental conditions where this occurs. |
particularly in temperate areas when environmental conditions become unsuitable, such as in seasonal extremes of high or low temperatures, or drought
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Dormancy may occur in summer __________
or in winter __________ and may involve either ___ or ___ |
aestivation (estivation)
hibernation quiescence or diapause |
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__________ is a halted or slowed development as a direct response to unfavorable conditions, with development resuming immediately favorable conditions return.
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Quiescence
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_____involves arrested development combined with adaptive physiological changes, with development recommencing not necessarily on return of suitable conditions, but only following particular physiological stimuli.
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diapause
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diapause at a fixed time regardless of varied environmental conditions is termed __________.
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obligatory
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which insect often have obligatory diapause?
why? |
univoltine
to extend an essentially short life cycle to one full year |
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Diapause that is optional is termed ____, and this occurs widely in insects, including bi- or multivoltine insects in which diapause occurs only in which generation?
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facultative
that must survive the unfavorable conditions. |
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what can facultative diapause be induced by?
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food
give an example of this : |
when prey populations of summer aphids are low, the ladybird beetles Hippodamia convergens and Semidalia unidecinotata aestivate, but if apids remain at high densities ( as in irrigated crops ) the predators continue to develop without diapause
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what describes the cessation or suspension or reproduction in mature insects (in adult stage)?
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reproductive diapause
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