Britannica Illustrated Science Library: Invertebrates by Encyclopedia Britannica

Author:Encyclopedia Britannica [Britannica, Encyclopedia]
Language: eng
Format: epub
Published: 2011-10-29T23:50:38+00:00

58 INSECTS

INVERTEBRATES 59

Types of Mouths

Far from being a mere opening, the mouth is

ANTENNA

usually one of the most complex parts

of an insect's body. The simple

oral appendages of the most

LOCUST

Family Acrididae

primitive forms were gradually

Since ancient times, locusts

modified so that this zoological

have been feared as a great

plague on crops.

group has been able to expand its

diet. Thus, a hunter's mouth is totally

1 day

different from that of a sucking insect or a

COMPOUND

EYE

leaf-eater, such as the locust.

THE TIME IT TAKES A LOCUST TO

EAT ITS OWN WEIGHT IN FOOD

Made to order

BITING AND

PIERCING AND

SUCKING

PUNCTURING AND

CHEWING

CHEWING

SUCKING

The oral appendages of

Antenna

primitive insects were

Antenna

Compound

modified considerably, and they

Compound

eye

Compound

took different forms according to

eye

Antenna

eye

the species. The first pair of upper

jaws is for holding and sucking the

food into the mouth. The second

Labrum

Compound

pair of upper jaws fuses at the

eye

midline during its development to

Lower jaw

Antenna

form the lip, a structure with

Labrum

different functions, depending on

Upper

jaws

Lower jaw

Upper jaws

Upper jaw

LEFT

the diet. The lower jaws and the

LOWER

first pair of upper jaws are at the

Lip

Lower jaw

Lip

Upper jaw

JAW

side of the mouth, and an upper

lip, the labrum, protects the front

BUTTERFLY

MOSQUITO (FEMALE)

LOCUST

Lip

of the mouth. These parts form

FRONT LEG

the basic biting-chewing

The lip and upper jaws

BEE

With a small labrum

apparatus. In more advanced

form a tube; the lower

Strong lower jaws

Lip for nectar; lower

and no lower jaw.

forms, its modifications give rise

jaws are for puncturing

and dexterous

jaws to chew pollen and

The upper jaws form

to structures for sucking and

the skin, and the labrum

upper jaws

mold wax

a suction tube.

licking or for biting and sucking.

forms a sheath.

LABRUM

PALP

(ON LIP)

Leaf Eaters

SEVEN-SPOT

LADYBUG

Insects such as locusts and some

Coccinella septempunctata

Eyelets

beetles, as well as caterpillars (and the

feeds on aphids, plant lice,

larvae of many other species) need a mouth

and sand flies.

Right

structure capable of cutting leaves into small serrated

Left

pieces and then putting them into the mouth.

lower jaw

serrated

For this purpose their large lower jaws have a lower jaw

series of serrated teeth, whereas the upper

jaws and the lip have palps for manipulating

and grasping the leaf pieces.

Palps of

right

upper jaw

Left upper

jaw, with

Lip

palps

CARNIVORES

with

use their jaws as

palps

pincers to grasp

Labrum

their prey.

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