Download introduction to order hemiptera

SPS Capacity Building Program (SPS CBP) presents:
TRAINING WORKSHOP ON ARTHROPOD PRESERVATION,
CURATION AND DATA MANAGEMENT
Museum Zoologicum Bogoriense, Cibinong, Indonesia, 26-30 September 2005
INTRODUCTION TO ORDER HEMIPTERA
Sri Suharni Siwi
LIPI
ASEANET
Widyasatwaloka
Reseacrh Center for Biology – LIPI, Cibinong
INDONESIA
1
INTRODUCTION TO ORDER HEMIPTERA
Sri Suharni Siwi
Suborder: Homoptera (Sternorrhyncha, Auchenorrhyncha), Heteroptera
(Greek: hemi = half; pteron = wing)
Common names: aphids, scale insects, white flies, leafhoppers, cicadas and bugs.
Distribution: Cosmopolitan
Hot to recognize (description):
The Hemiptera are the dominant group of exopterygota insects. They range in
length from less than 1 to 110 mm, and comprise insects with a great range of different
structural and behavioral features and occupying a wide variety of environment.
The most characteristic features is the structure of the mouthparts, which are highly
efficient for extracting the liquid contents of plants or animal prey. Bugs possess
piercing-sucking mouthparts in a simple tube (rostrum) formed by modification of the
insect’s lower tip (labium). Inside the tube, modified mandibles from canals which allow
an upward flow of liquid food and a downward flow of saliva. The modified mandibles
are called sylets. Often the rostrum is held under the head but is brought forward during
feeding. Compound eyes are usually present and well developed; simple eyes (ocelli)
may be present. Antennae may be short with only a few segments, or well developed and
more less filiform. Most species possess two pairs of wings, but some have only one pair
and a few species have none. The order name describes a character of the many bugs in
which the front pair of wings is modified so that the basal half of each wing is hardened
(sclerotic) to form a protective cover (a hemelytra). As the wing bugs are folded flat on
the abdomen, this makes the insect appear as if half of each of forewings is missing. In
the remainder of the order, the wings are held over the abdomen rather like two sides of a
house roof (cicada, etc.).
Most Hemiptera are terrestrial and phytophagous. In suborder of Homoptera, the
family Cicadellidae is a very diverse of group of Auchenorrhyncha, and the largest in
number, more than 15.000 species described. Most species are phloem feeders and
2
important as vector of virus diseases. At species level, examination of the male genitalia
is essential.
In suborder Heteroptera (true bugs), include groups which are carnivorous and often
produce a repellent odour-used for defense from a specialized gland. Many of which are
also aquatic, such as water boatman (family Corixidae).
Members: Bugs, water strides, water scorpion, water bugs, water boatman, cicadas,
leafhoppers, spittlebugs, aphid, psyllids and whiteflies.
Habitat, Plant, Food: Bugs feed on liquid obtained from plant or animals including man.
Any part of the plant may used as food: leaves, stems, fruits or roots. Blood is consumed
by some species, while others consume insect body fluid.
Importance:
The plant feeding bugs are considered serious pests in agriculture such as brown
plant hoppers Nilaparvata lugens in rice plant and the green leafhopper Nephotettix
virescens, besides direct feeding also act as vector of virus diseases.
Scale insect
infestations can seriously damage citrus crops and ornamentals, and aphid attack can
harm various ornamentals such as Macrosiphum rosae in roses.
The characteristics of Aphids: soft-bodied insects up to 4 mm long; most have a pair of
siphunculi/cornicles towards the posterior end of the abdomen and long antennae. They
often form large colonies on leaves and stems. In the tropics, about 30 species are pests. .
Many species have been implicated as major vectors of plant virus diseases, but damage
by sap depletion, saliva toxicity and sooty mould growth can also be serious.
How to collect and handle the Hemiptera:
Since different species are active at different times of the day, at least some kinds of
insects can be collected at any hour. Terrestrial Hemiptera may be collected with a net
(particularly by sweeping vegetation), at lights, aspirator, baiting trap or by examining
such specialized habitats as leaf litter, under bark and in fungi. The aquatic bugs can be
collected by means of the aquatic collecting equipment.
3
Preservation:
Kill and preserve nymphs in 80% ethanol. Most Hemiptera adults are preserved dry
on pins or points. Pin large Heteroptera through the right side of scutellum (hemelytron);
care must be taken in pinning not to destroy structures on the ventral side of the thorax
that will be used in identification. Pin medium sized species through base of right wing.
Very small Heteroptera may be glued to apex of card triangle with its tip bent down.
Set left pair of wings of Auchenorrhyncha with anterior margin of hindwing at right
angles to body and forewing immediately in front. Most Hemiptera, less than 10 mm in
length should be mounted on points, or should be stages on micropin and pith or glued to
apex of card triangle with specimen lying on its left side. Specimens mounted on points
should be mounted so that the beak, legs, and ventral side of the body are not embedded
in glue. If specimen is mounted dorsal side up on the tip of a point, the point should not
extend beyond the middle of the ventral side of the insect.
Kill and preserve Stenorrhyncha in 80% ethanol. Scale insect may be preserved dry
on host plant and placed in vial.
Killing bottle made for most Hemiptera is a small bottle or larger bottle depend on
the size of insect to be killed, at the based poured with sodium or potassium cyanide,
finely granular or powdered form with wet plaster. After the wet plaster has been poured
in, the bottle should be left uncorked a day or two, until the plaster has thoroughly set and
dried, then it is corked. A poison label is put on. Another material that can be used as
killing agents in insect bottles is ethyl acetate, carbon tetrachloride and chloroform. Ethyl
acetate is the least dangerous of the three to use.
Mounting on microscope slides
Many small arthropods (thrips, lice, fleas, mites, aphid) or isolated body parts as
genitalia are best studied when mounted on microscope slides. Material so mounted is
generally transferred to a slide from preserving fluid, and the mount may be temporary or
permanent. The media for temporary slides mounts are glycerine, and for permanent
4
slides mount the most commonly used resin is balsam. Specimens mounted in a resin
must first be dehydrated (by running through successively increasing concentration of
alcohol: 70, 95, 100 %)., and then through xylol and into resin. For dark colored or thick
bodied specimens or such structures as genitalia, must be cleared before mounting.
Several substances used as clearing agents is potassium hydroxide (KOH), that can
be used for almost any arthropod or arthropod structure. After clearing in KOH, the
specimens should be washed in water (preferably with a little acetic acid added) to
remove any excess of the KOH. KOH can be used cold that the clearing may require
from a few hours or warm, the specimen may be boiled in few minutes. It is sometimes
desirable to stain an insect before it is mounted, very commonly used is acid fuchsin.
5