Some Orders of Insect Pests 511 Zoo Prepared by: Dr. Reem Alajmi

Thysanura: The bristletails (silverfish and firebrats) Adult Description and identification: Mouthparts: chewing Size: Common species are about 12 mm long. Wings: None Distinguishing characteristics: Elongate and somewhat flattened; body covered with scales; 3 caudal filaments, 2 lateral, 1 central.. Metamorphosis: None (ametamorphosis); immature (called juveniles) look like adults.

Thysanura: The bristletails (silverfish and firebrats) Habitat: Debris, under bark, in buildings (some cool and damp, others warmer sites). Pest or Beneficial Status: Primarily nuisance, some property damage by silverfish and firebrats (may feed on starch of book bindings, similar materials).

Left: a silverfish. Right: a firebrat

Ephemeroptera: The mayflies Adults: Mouthparts: None (vestigial) Size: 2 – 32 mm long, plus long caudal filaments Wings: Usually 4, some species only 2. Membranous, with numerous net-like cross-veins. Fore wings are larger, triangular.

Ephemeroptera: The mayflies Other distinguishing characteristics: Short hair-like (setaceous) antennae; 2 or 3 long caudal filaments. Habitat: Immature are aquatic; adults are found near water. Most nymphs feed on algae or decaying organic material; some are predaceous. Metamorphosis: Incomplete (naiads do not look like adults and live in water; wing “pads” develop gradually and externally through successive stages.

Ephemeroptera: The mayflies Immatures (called naiads): Leaf-like abdominal gills; 3 long caudal filaments; (sexually immature pre-adult) emerges from the water, molts to the adult stage the next day. Pest or Beneficial Status: Important fish food; indicators of water quality; mass emergence may be problematic.

Odonata: The dragonflies and damselflies Adults: Mouthparts: Chewing Size: 20 to 135 mm. Wings: 4, membranous, with numerous net-like cross-veins. Wings are marked by a stigma -- a thickened, darkened cell at the costal margin of the fore and hind wings.

Odonata: The dragonflies and damselflies Other distinguishing characteristics: Very large compound eyes; short hair- like (setaceous) antenna Suborder Anisoptera: dragonflies -- hind wings wider than front wings; wings held horizontally at rest. Suborder Zygoptera: damselflies -- fore and hind wings similar in shape and narrowed at base; wings held together above the body when at rest.

Odonata: The dragonflies and damselflies Left: A dragonfly (Texas A & M University). Right: A damselfly (University of Florida).

Odonata: The dragonflies and damselflies Metamorphosis: Incomplete (naiads do not look like adults and live in water; wing “pads” develop gradually and externally through successive stages.) Immatures (called naiads): Aquatic; labium modified to catch prey; dragonflies with internal (rectal) gills; damsel fly naiads with 3 leaf-like gills at the end of the abdomen.

Odonata: The dragonflies and damselflies Habitat: Immature are aquatic; adults are found near water. Nymphs and adults are predaceous. Pest or Beneficial Status: Generalist predators; indicators of water quality.

Orthoptera: The grasshoppers, crickets, and katydids Adult Mouthparts: Chewing Size: Moderate to large Wings: 4, front wings (tegmina) are leathery, hind wings are membranous. Some are wingless. Wings (and legs) may bear sound-producing structures.

Orthoptera: The grasshoppers, crickets, and katydids Other distinguishing characteristics: Elongate bodies; well-developed cerci; antennae are mostly long and filiform; the ovipositor may be long; hind legs of most are modified for jumping.

Orthoptera: The grasshoppers, crickets, and katydids Metamorphosis: Gradual. Immature (nymphs): Are adult-like, and external wing pads develop as nymphs mature. Habitat: Many types of vegetation

Orthoptera: The grasshoppers, crickets, and katydids Pest or Beneficial Status: Some grasshoppers are crop pests; some crickets are household nuisance pests. In some parts of the world, migratory locusts occur in great numbers and destroy vast areas of crops and other vegetation.

Dermaptera: The earwigs Adults Mouthparts: chewing Size: 4 - 30 mm Wings: 4 or none; forewings shortened and thickened; hind wings membranous and folded. Distinguishing characteristics: Enlarged, pincer-like cerci.

Dermaptera: The earwigs Habitat: Moist debris and decaying materials. Earwigs are nocturnal and feed on plants or decaying plant material; some are predaceous (and beneficial). Metamorphosis: Gradual; nymphs resemble adults and share the same habitat. In those with wings, external wing pads develop as nymphs mature. Immature (called nymphs): Similar to adults.

Dermaptera: The earwigs Pest or Beneficial Status: Earwigs are usually pests only as nuisance creatures, but one species, the European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), is a pest of vegetables, ornamental plants, and fruits. Its feeding leaves scars on the surface of apples and pears.

Hymenoptera (sawflies, parasitic wasps, ants, wasps, and bees) Adult Mouthparts: chewing or chewing/lapping Size: Minute to large Wings: 4 or none, front wing larger than hind wing, front and hind wings are coupled by hamuli to function as one.

Hymenoptera (sawflies, parasitic wasps, ants, wasps, and bees) Antennae: Long and filiform (hairlike) in Symphyta; many forms in Apocrita Other characteristics: Abdomen is broadly joined to the thorax in Symphyta; constricted to form a "waist"-like propodeum in Apocrita.

Hymenoptera (sawflies, parasitic wasps, ants, wasps, and bees) Metamorphosis: Complete Immatures: In Symphyta, eruciform (caterpillar-like), but with 6 or more pairs of prolegs, all are plant- feeders. In Apocrita, larvae have true head capsules, but no legs; some feed on other arthropods Habitat: On vegetation, as parasites of other insects, in social colonies

Hymenoptera (sawflies, parasitic wasps, ants, wasps, and bees) Pest or Beneficial Status: A few plant pests (sawflies); many are beneficial as parasites of other insects and as pollinators. Honey bees are important pollinators and produce honey. Stinging species can injure humans and domestic animals.

In a group of three, make small presentation within 2-3 slides for one of the insect pests order that is not mention in this lecture…