Taxonomical Relationship of Insect Predators
Sweetman (1936) recorded about 14 Orders with 167 Families for predatory insect representatives. He further added in 1950, 2 more orders and some 42 families. The orders Coleoptera, Neuroptera, Hymenoptera, Diptera and Hemiptera contain families that so far have been of major importance in biological insect pest suppression. Greatest numbers of predatory species occur in order Coleoptera. The order Onodata is exclusively predaceous.
Taxonomic Characteristics of Important Predatory Insects:
1) Predaceous Coccinellids:
The lady bird beetles (Coleoptera; Coccinelidae).
a) The adult beetles have bright body in various shades of red, brown, tan or even black.
b) Usually they are spotted.
c) They range from 2-6 mm in length and are hemispherical in shape.
d) The head is small with chewing type of mouth parts.
e) The antennae are short and elevate.
f) Tarsi 3 segmented.
g) Larvae usually elongate with gradually tapering bodies. The body regions are distinct and colored with blue, black or orange. They appear warty of spiny dorsally.
The ground beetles (Coleoptera: Carabidae)
a) The beetles through predominantly black have some brilliantly colored in metallic greens, blues or purple.
b) Most species have broad elytra, narrow pronotum and a still narrower head.
c) They range from 2-25 mm in length.
d) The legs are long allowing for rapid movement.
e) The antennae are attacked between eyes and mandibles on each side of head.
f) The larvae are slightly flattened and slender tapering towards the posterior end which bears two spine like processes. They have chewing type of mouth parts.
The green lace wings (Neuroptera: Chrysopidae)
a) These are slender bodied insects. Colored in a delicate green with golden eyes.
b) Antennae are long and slender.
c) Forewings are almost equal in size with green veins which fork profusely near wing margins.
d) The adults of some species and all of the larvae are predacious.
e) The spindle shaped larvae called”aphid-lions” have powerful sickle shaped mandibles. The legs are slender and hairy and body is provided with a row of spine bearing tubercles along each side Aphid-lions are usually mottled with grey, yellow, green red or black.
The ants (Hymenoptera: Formicidae)
a) These are social insects. Many displaying polymorphism.
b) They have chewing type of mouth parts.
c) The antennae are strongly elbowed with a very long first segment.
d) Body segments are distinct and thorax is slenderest region. The gaster or swollen part of the abdomen is attached to the thorax with a short slender petiole bearing one or two projectious.
The entomophagous syrphid flies (Diptera, Syrphidae)
a) They are predators only in their larval stages.
b) Adults are diverse in form, some slender and some broad and their bodies are polished black or metallic blue or green with prominent yellow bands, spots or hairs.
c) They are 3 to 25 mm long and are separable from others Dipters by the presence of spurious wing vein between radius 4+5 and media 1+2.
d) The green or tan larvae are elongate, legless maggots with pointed sucking mandibles.
The plants bugs (Hemiptera: Miridae)
a) The plant bugs contain many predaceous species.
b) Adults are 2.5 to 6 mm long, velvety in appearance and often highly colored. They have cureus and 1-2 large cells in the membrane of fore wings, both rostrum and antennae 4 segmented and no ocelli.
c) The body is elongate oval and often clothed with fine hairs. The hemelytra are longer than abdomen and prevailing colors are combinations of green, black or red with spots or stripes of black, yellow, white or red.
d) Mirids have sucking type of mouth parts.
e) Metamorphosis is incomplete and nymph is predaceous.