第二章昆虫的生物学特征

第二章
生物学特性
Chapter2 Biological Characteristic
• 一,本章重点是基本概念和名词:
• 1.两性生殖sexual reproduction
• 2.孤雌生殖parthenogenesis
• 3.幼体生殖paedogenesis
• 4.多胚生殖polyembryony
• 5.变态metamorphosis
• 6.龄期stadium or instar
• 7.羽化emergence
• 8.补充营养supply nourishment
• 9.多型现象polymorphism
• 10.世代,世代重叠generation overlapping
• 11.休眠dormancy,滞育diapause
• 12.日出性diurnal insect和夜出性昆虫nocturnal insect
• 13.趋性taxis,迁飞flying
• 14.变态类型,卵的类型,根据刺激源可将趋性分为什么?

第二章
生物学特性
Chapter2 Biological Characteristic
• 二. 昆虫的生长与发育
• The Growth and Development of Insects
• Eggs: Insect eggs differ in shape and color, and some are
ornamented with ridges, spines, or other processes. Most
insects lay their eggs in a situation where the young on
hatching will have conditions suitable for development. Many
lay their eggs in characteristic masses, and a few cover their
eggs with a protective material of some sort. The eggs of some
insects develop internally, and the young are born alive.
• Growth: The Growth of an insect is accompanied by a series of
molts, in which the exoskeleton (outer shell) is shed and
renewed. Insects change in form as they grow, and the amount
and character of this differ from group to group. This change is
called metamorphosis(变态).

第四章
昆虫发生与环境的关系

第二章
生物学特性
Chapter2 Biological Characteristic
• 二. 昆虫的生长与发育(egg larva pupa adult)
• The Growth and Development of Insects
• 变态(metamorphosis): Successive instars differ not only in size but in other features
as well. This change during growth (metamorphosis) is relatively slight in some insects,
very marked in others. There are 2 principal types of metamorphosis---simple and
complete.
•
• Simple metamorphosis: In this type the wing develop externally during the
early instars, compound eyes are present in the early instars if they are present
in the adult, and there is no prolonged resting stage before the last molt. The
immature instars of insects with this type of metamorphosis are called nymphs.
• Complete metamorphosis: The eggs of insects with complete metamorphosis
hatch into a wormlike stage called a larva. The larvae of insects vary in
appearance: some have legs and others are legless and some lack a well-
developed head. Larvae do not have compound eyes(but may have ocelli), and
if the adult is winged the wing begin their development in the larval stage but
develop internally. The larval stage lasts from a few to several instars,
increasing in size and sometimes changing in color or other characters. After
the molt of the last larval instar the insect changes to what is called a pupa.
Pupae are usually inactive. They do not feed, and are sometimes enclosed in a
protective covering, which may be a conoon formed by the last larval instar
before it molted or may be a puparium (formed of larval exoskeleton).

三
昆虫的生活史(Life history)
• Life history: most insects in our area have a single generation a
year. The adults are present for a limited time during some part
of the year, and the winter is passed in a dormant state. Insects
overwinter in different stages– some as eggs, some as nymphs,
some as larvae, some as pupae, and some as adults. A period of
dormancy at low temperature is often an essential feature of the
life cycle. Many insects will not complete their development
unless exposed to low temperature.
• Generation: Some insects regularly have 2 generation a year and
others may have several—continuing to reproduce as long as
weather conditions are favorable. A few require more than a year
to complete their development. Many of the larger insects in
northern areas take 2 or 3 years; the record holders are some of
the periodical cicadas(蝉), which take 17 years.
• 成虫(adult): Adults of most insects live only a short time,
ordinarily from a few days to a few weeks. An overwintering adult
lives several months, and the queens of some socil insects can
live several years. Many insects that are shot-lived as adults do
not feed in the adult stage.

第四章
昆虫发生与环境的关系

粉纹夜蛾
Trichoplusia ni
Cabbage looper
Eggs Larvae

斜纹夜蛾
Spodoptera
litura (F.)
Common Leafworm Adult
1.It is a totally polyphagous pest and feed on a very wide range of crops including vegetables, cotton, rice, tomato and tobacco. Other host
plants include Citrus, cacao, sweet potato, rubber legumes, sorghum, maize etc.
2.Distribution:It mainly distributes in South and Eastern Old World tropics, including Pakistan, India, Bangladesh, Sri Lanka, China,
Korea, Japan, Thailand, Vietnam, Philippines, Indonesia, Austral-Asia, Pacific islands, Hawaii and Fiji.
3.Damage:This caterpillar is basically a leaf-eater. Heavy infestations can seriously defoliate the crops, especially the young plants.
• Newly hatched larvae are gregarious and remain together and skeletonize the leaf on which they feed. Later they disperse and
become more solitary and nocturnal in habits. One generation can be completed in as little as 24-30 days, and in the humid tropics
there may be 8 generations annually.
4. Identification:
• Adult : The adults are pale brownish moth, with the yellow-brown forewing having a distinctive pale band medially: wingspan is 30-40 mm.
• Eggs:Eggs are spherical (0.3 mm) in diameter, and laid on the undersides of leaves in batches of 100-300 and
covered with yellow colored hair-scales.Each female lays about 100-2000 eggs, hatching requires 2-6 days.
• Larvae:The newly hatched larvae are pale green at first, and with a distinct black band on the first abdominal segment. Later they
become brown with dark marking, with yellow lateral and dorsal stripes.The lateral yellow strip is bordered dorsally with a series
of semi-lunar marks.
• Pupa :Pupation takes place in the soil in an earthen cell, just beneath the surface, The pupa is dark red, 15 -20 mm long.
Eggs Larvae

小菜蛾 Plutella xylostella (L.)
Diamondback moth

蔬菜蚜虫
Vegetable aphids
1 萝卜蚜
Lipaphis erysimi
Turnip Aphid
2 桃蚜
Myzus pericae
Green Peach Aphid
3 甘蓝蚜
Brevicoryne brassicae
Cabbage Aphid
1. Cabbage aphid and turnip aphid mainly feed on
cruciferae. Cabbage aphid prefers cabbage and
other Brassica spp but turnip aphid likes Chinese
cabbage and radish better. Green peach aphid is
truly a polyphagous species; about 875 plants in 35
different families are recorded as its hosts. The
main host is peach, the alternative hosts include
potato, tomato, tobacco, beet, cereals and
vegetables. All three species of aphids occur
commonly and mixed on cruciferous vegetables in
China.
2.Distribution
• Cabbage aphid: The aphid distributes throughout
Turnip Aphid
the world in temperate and subtropical climates.
•
In China it occurs nearly all parts of the country
besides Tibet .
Turnip aphid: Mostly in temperate and subtropics
regions. In China it is dominate species in
Xinjiang autonomic distract.
• Green aphid: A completely cosmopolitan species
with a worldwide distribution.
• All species of the aphids occur year around in
South China. No eggs are found in the host plants
during the winter. All stages of the pests can be
found on the vegetable crops in winter season.
They reproduce by parthenogenesis. The
population increases very rapidly under favorite
conditions.
3.Damage:
Green Peach Aphid
• Cabbage aphid: The aphid attacks many crucifers,
especially cabbage, cauliflower. It is known to
transmit a number of virus diseases in the host
plants. Nymphs and adults suck plant sap, causing
distortion, stunting. curling, wilting and often lead
to death of these host plants when severely attack
happened.
4. Identification
• Turnip Aphid: Turnip aphid is similar to the
cabbage aphid in appearance, but has a more
distinct green to yellow-green yellow green color with less
noticeable powdery wax on the body, and it lacks
the dark transverse marks on abdomen.
• Green Peach Aphid: Green peach aphid is rather
slender in form, light green or yellow, with
•
indefinitely darker stripes on the abdomen. abdomen
Cabbage Aphid: Cabbage aphid is grayish-green grayish green in
Cabbage color and the body is covered Aphid
with a fine powdery
wax, which gives heavily infested plants a whitish
appearance.

甜菜夜蛾
Spodoptera exigua
Beet Armyworm
Adult
1.It attacks more than 170 different species of host plants including cabbage, radish, lettuce, eggplant, pepper,
tomatoes, potatoes, beans gourds, rice, cotton, sugar beet, tobacco, etc.
2.Distribution:Africa, Southeast Asia, Central and South Europe, Middle East, Australia, Southern USA, India,
Southern China, Philippines, Indonesia, and Canada.
3.Damage:Young larvae eat foliage within webs underside of the leaves. The caterpillars are gregarious, moving in
swarms, and destroying the young leaves and stems of the host plants. Young seedlings can be completely
destroyed, but older plants often recover after an attack and may be still vigorously. Young larvae skeletonize
the underside of the leaves, but later as they grow they eat the entire lamina. In South China there are usually
eight generations.
4. Identification:
• Adult:The adult is a small brown moth of wingspan up to 25 mm, and the fore wing is grayish-brown with two
yellow spots near the center. The hind wing is a translucent white with narrow brown borders, There are
rather nondescript in appearance and not easy to recognize.
• Eggs:Eggs are laid on the leaves of the host plants, in clusters, several layers thick, and covered with hairs from
the female abdomen. Each cluster contains 50-300 eggs, one female can lay 300-900 eggs (up to 1700). Eggs
usually hatch after 2-4 days.
• Larvae:The larvae are very gregarious, at first green, later becoming variable green or brown usually with a
lateral strip. Young larvae Eggs skeletonize the underside of the leaves, Larvae
but as they grow they eat the entire
lamina.Pupa: Pupa:Pupation takes place in the soil and lasts about 6 days.

Homework
Chapter2 Biological Characteristic
• 一,本章重点是基本概念和名词:
• 1.两性生殖sexual reproduction
• 2.孤雌生殖parthenogenesis
• 3.幼体生殖paedogenesis
• 4.多胚生殖polyembryony
• 5.变态metamorphosis
• 6.龄期stadium or instar
• 7.羽化emergence
• 8.补充营养supply nourishment
• 9.多型现象polymorphism
• 10.世代,世代重叠generation overlapping
• 11.休眠dormancy,滞育diapause
• 12.日出性diurnal insect和夜出性昆虫nocturnal insect
• 13.趋性taxis,迁飞flying,假死性feign death?
• 14.变态类型,卵的类型,足的类型,蛹的类型?
• 15.根据刺激源可将趋性分为什么?
• 16. .螨类与昆虫的区别?

测验题(三)(20分钟)
• 1.两性生殖?
• 2.孤雌生殖?
• 3. 多胚生殖?
• 4.变态?
• 5.龄期?
• 6.羽化?
• 7.补充营养?
• 8.休眠和滞育有什么区别?
• 9.趋性?根据刺激源可将趋性分为 什么?
• 10. 螨类与昆虫的区别