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PALEONTOLOGICAL SOCIETY PAPERS, V. 8, 2002Endoneoptera, or Holometabola (Haas andKukalová-Peck, 2001). This latter group ischaracterized by a four-phase metamorphosis— egg,to larva, to pupa, to adult—and includes all the ordersfrom Megaloptera (alderflies and dobsonflies) toHymenoptera (sawflies, wasps, ants, and bees) inFigure 4. Holometabolous insects represent about90% of all insect species, and insects represent 86–92% of all known metazoan species (Wheeler, 1990;Brusca, 2000). They have been the mosttaxonomically, if not numerically dominant animalclade since the earliest Pennsylvanian.Continental carnivorous hexapods have twokey structures: mouthparts and ovipositors. Thegeneralized mandibulate mouthparts of theprimitive hexapod (Kukalová-Peck, 1990) havebeen modified into 34 major types, all extant, eachof which represents considerable to subtlevariations on a basic plan (Labandeira, 1997a). Forexample, the broader category of mandibulocanaliculatemouthparts comprises three of the 34mouthpart classes; each of these three ischaracterized by unique features associated withscythe-shaped mandibles and/or associatedmaxillae that are used by larval holometabolans forpursuit or entrapment of prey (Labandeira, 1997a).Other examples include the structurally diversestylate mouthparts of fluid-feeding ectoparasites(Smith, 1985), and the analogous concealed nectarextraction apparatus used by parasitoid adults at acertain stage in their life cycle (Jervis and Kidd,1986). Similarly, the ovipositor has been used byparasitoids, especially hymenopterans, to inserteggs into hosts such as wood-boring larvae.The record of hexapod carnivory (Fig. 4) showsthree basic trends, each corresponding to the riseof family-level lineages representing the threefunctional feeding groups: predation, parasitoidism,and parasitism. The first trend is the expansion ofinsect predators during the Late Paleozoic. Thesecond is the spectacular diversification ofparasitoid groups during the Middle Jurassic tomid-Cretaceous. And the third trend is the radiationof parasitic groups during the Late Jurassic to mid-Cretaceous, lasting into the Paleogene. Twoancillary patterns should also be noted. One is thebeginning of heavy seed predation during themiddle Cretaceous to Paleogene—although theichnofossil and functional morphological evidencefor seed endosperm consumption extends back tothe Late Carboniferous and Early Permian (Sharov,1973; Scott and Taylor, 1983). Post-Paleozoic seedpredators and parasitoids include stylate piercingand-suckingand mandibulate chewing forms, andare concentrated in three clades: pentatomorphHemiptera, “phytophagan” Coleoptera, andchalcidoid Hymenoptera. A few families ofLepidoptera are notable larval consumers ofendosperm (Janzen, 1971), but lack fossil records.The other secondary trend is reflected in the ancientrecord of palynivory (sporivory and pollinivory;Taylor, 1981), which is analogous to predation ongametophytic seeds, representing consumption ofthe sporophyte phase of a vascular plant. There arefour specific pollinivorous evolutionaryassemblages, defined by plant taxa consumed andassociated consuming insects (Labandeira, 1998b,2000). Palynivory and predation and parasitoidismon seeds will not be considered further.Predators.—The earliest terrestrial predatorswere chilopods and several major chelicerate taxa,with first occurrences during the latest Silurian toMiddle Devonian; several additional lineages appearduring the earlier Pennsylvanian (Fig. 3). Amongthe hexapods, the Odonatoptera—withapproximately 20 family-level taxa—were thedominant airborne predators, including somemembers of the Meganeuridae with wingspans upto 71 cm (Durden, 1988). These large forms wereprobably the ecological equivalent of birds, andcaught their victims on the wing, judging by theirwell-developed raptorial mandibles, leg baskets forsecuring prey, and canted thoracic segments(Rohdendorf and Rasnitsyn, 1980; Brauckmannand Zessin, 1989). Ground-dwelling, LatePaleozoic hexapod predators included severalfamilies of protorthopterans, as revealed by taxa withspinose and raptorial forelegs, and robust andincisiform mandibles. Early holometabolan lineagesof the neuropteroid complex—Megaloptera,Raphidioptera, and Planipennia—originated duringthe earliest Permian (Asselian); virtually all of their228