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(EE, pp. 174-187) Alderflies, dobsonflies, snakeflies, lacewings and antlions.

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Presentation on theme: "(EE, pp. 174-187) Alderflies, dobsonflies, snakeflies, lacewings and antlions."— Presentation transcript:

1 (EE, pp ) Alderflies, dobsonflies, snakeflies, lacewings and antlions

2 We are entering a new Subdivision - the Endopterygota! this group contains the most ‘advanced’ and most successful insect orders young stages are called larvae - look different from the adults they become their wings develop internally (endopterygote) metamorphosis is complete (holometabolous) transformation from larva to adult takes place during the pupal stage

3 Phylogeny of Hexapoda from p. 52 Megaloptera Raphidioptera Neuroptera

4

5 Megaloptera Common name: Alderflies and dobsonflies (300 known world species (0.03%)) Derivation: Gk. megalo - large; pteron - a wing Size: Body length mm; wingspan mm Metamorphosis: Complete (egg, larva, pupa, adult) Distribution: Widespread, but mainly temperate regions Number of families: 2

6 Key Features acquatic larvae adults always near water

7 often referred to as toe-biters Megaloptera (conspicuous jaws, but adults do not feed)

8 the alderflies (Sialidae) Megaloptera (only two families)

9 the dobsonflies (Corydalidae) Megaloptera (only two families)

10 two pairs of wings with.... hind wings are.... hind wings usually.... Megaloptera (not good flyers - flutter weakly and alight readily)

11 What about mating? (mating takes place on marginal vegetation or on the ground) females produce a large number of eggs that stick to reeds or other plants hanging over the water some male dobson flies (e.g. Protohermes) attach a jelly-like, external spermatophore to the genitalia of the female Protohermes

12 they have simple or branched, abdominal gills (similar in appearance to water beetle families when young larvae hatch, the drop or crawl into the water using their well- developed legs What about the larvae? (all megalopteran larvae are aquatic and predacious)

13 Common name: Snakeflies (200 known world species (0.02%)) Derivation: Gk. rhaphe - a needle; pteron - a wing Size: Body length 6-28 mm Metamorphosis: Complete (egg, larva, pupa, adult) Distribution: Northern hemisphere Number of families: 2 Raphidioptera

14 Key Features ‘long-necked’ in woodland

15 Raphidioptera (how do they differ from Megaloptera?) larvae are completely terrestrial the adult stage feeds

16 What else do we know? (snakeflies are not particularly well studied) they are found in wooded areas especially among rank vegetation adults and larvae like to feed on aphids and other soft-bodied insects several hundred eggs are laid, in groups of up to 100, in slits and cracks in tree bark or rotting timber

17 Common name: Lacewings, antlions, and their relatives (5000 known species (0.5%)) Derivation: Gk. neuron - sinew, nerve; pteron - a wing Size: Body length 2-90 mm; wingspan mm Metamorphosis: Complete (egg, larva, pupa, adult) Distribution: Worldwide Number of families: 18 Neuroptera

18 Key Features elongate... prominent.... wing venation....

19 spoonwing (nemopterid) Neuroptera (noted for elaborate venation pattern on the wings) ascalaphid myrmeleonid

20 Neuroptera (occur worldwide, but many families have restricted regions) majority are predacious (as larvae and adults) mainly active in the evening or after dark some species look like other groups mantispid ascalaphid

21 Larval morphology (varied and very much linked with lifestyle) free-living hunters are slender with longish legs, and often have an adhesive disc-like structure on the last two abdominal segments (for clinging to foliage) pit-building or ambushing species tend to be fat and squat with short legs, very large jaws and extended necks

22 Antlion larvae (larvae live at the bottom of conical pits with only jaws showing)

23 Larval morphology (strong, sickle-shaped mouthparts are highly modified sucking tubes)

24 More about the larvae (interesting gut morphology and development) eggs laid on a stalk the hindgut is not united with the midgut, only fluids are expelled and any solid material is passed as meconium when the adult first emerges (the guts join up in the adult) generally mature after 3 instars - pupate inside a spherical, silk coccon

25 Neuroptera (many are directly and indirectly beneficial in controlling insect pests) green lacewings (Chrysopidae) are voracious predators of aphids, thrips, psyllids, scale insects, coccids and mites


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