Transcript Hymenoptera
HYMENOPTERA IMPORTANT POINTS • 3rd or 4th most species-rich order. • “Membrane-wing”; well developed ovipositor; most live in constructed “nests”. • Includes: sawflies, parasitoids, “wasps”, ants, & bees. • “Wasp” = general, paraphyletic term; may describe almost any hymenopteran. • Many “beneficial” species but also many pests. • In many habitats may be most numerous insects in numbers of individuals because of social species with large colonies, especially ants, which may be “keystone” species. • Bees are the primary pollinators of zoophilous vascular plants; they are linked to survival of the earth’s modern vegetation. Taxonomy & Diversity Suborder SYMPHYTA sawflies <10% of species Suborder APOCRITA Division Parasitica, parasitoids, >70% of species Division Aculeata, stinging wasps, ants, & bees ~20% spp. Phylogenetic hypothesis for the evolution of the Hymenoptera IMPORTANCE Natural World “The little things that run the world.” --E. O. Wilson Special ecosystem functions: • Resource cycling, especially ants • Population control, parasitoids, predators • Pollination (plant reproduction), bees, others IMPORTANCE Anthropophilic World Beneficials • Bioloical Control: horticultural & agricultural • Pollinators: honey bees, bumble bees, solitary bees • Hive Products: honey, wax, misc. Pests • Agriculture: phytophagous sawflies • Structural damage: carpenter bees & ants • Nuisance: stinging wasps, ants • Medical: stings to allergic individuals, trauma Typical Features of HYMENOPTERA Sawflies vs. Apocrita • Larvae • Wings • Mouthparts Larvae Sawflies: caterpillar-like, one pair stemmata, > 6 pair prolegs; free-living. Apocrita: grub-like maggots, relatively featureless; live in protected nest cells. lepidopterous caterpillar > 6 prolegs multiply-segmented antennae single stemma SYMPHYTA, sawflies from Peterson 1962 from Borror, Triplehorn & Johnson, 1980 sawfly larvae Larvae of APOCRITA • live in protected spaces • fed by adults • soft, grub-like, reduced features from Peterson 1962 Wings Sawflies: always 2 pair, veination heavy, basic Apocrita: 2 pair or one sex apterous, venation often reduced, mambrane may be patterned, fore- & hindwings attached with hammuli. representative sawfly wings Wings of Apocrita Chalcidoid (parasitoid) wings, Most very small, reduced veins Wings of aculeate wasps & bees, normal size, rel. full veination Wing coupling velcro-like hamuli Adult Mouthparts Sawflies: chewing or nonfunctional Apocrita: may be highly modified with manipulative, chewing mandibles, maxillae & labium formed into a liquid-sucking device. In some very long for feeding from deep-corolla flowers. Mouthparts from Snodgrass honey bee mouthparts tongue of a Euglossine bee Other Features of APOCRITA Abdomen mesosoma metasoma propodeum petiole gaster Propodeum & gaster configurations in APOCRITA Sting • Modified abdominal tergites/sternites • Double stylet with levering valves at base • Venom glands in some spp. • Evolution: Ovipositor Host-paralysing Defensive Sting parasitoid, egg-laying aculeate bee or wasp, offensive, defensive specialized, barbed honey bee sting Genetics Haplodiploidy is the rule: Female 2N, Male 1N Sociality Symphyta & Parasitica, solitary Aculeata, most solitary but many social Multiple origins of sociality, even within families, e.g. sweat bees Parasitoids: Natural & Agricultural Biocontrol parasitoid & host chalcidoids aphid mummies Braconid wasp ovipositing into lepidopterous pupae. Pupae of a parasitoid formed on host’s exterior as larvae exit. some cynipid galls A parasitoid cynipid ovipositing into a gall made by a gall-making cynipid. Cynipidae, gall-wasps and parasitoids cuckoo wasp (Chrysididae) velvet ant (Mutilidae) Charismatic aculeates. “Acule” = “spear”. Important features of non-parasitic Aculeata “Central-place” foragers: Nests Complex behavior, homing ability + Larval protection - Requires defense - Energetically expensive - Resource dependent Vespidae: yellow jackets, paper wasps: pests & beneficials larva Nest-building Provisioning (hunting) Egg-Laying Larval Development • An important clade within the Hymenoptera • Specialized wasps • Food: nectar & pollen (not predators, as their close relatives) • Coevolved with vascular plants • Pollinaton Natural World Anthropophilic world (agriculture) More on BEES later… Red Imported Fire Ant Solenopsis invicta • Native to the Pantonal, a semitropical region in SW Brazil • Introduced early 1900’s in Alabama • Exotic pest with no natural enemies explosive population growth • Expansion to many warm regions • Native counterparts in genus Solenopsis ~2008 Original introduction, 1920’s RIFA range in USA (slightly outdated) Typical mode of infestation showing early mound development. Closely-related colonies may form “super colonies” covering many square miles. queen RIFA caste polymorphism day 1 ~ 1 week typical RIFA welts & pustules dense population of RIFA in pasture A generalist, RIFA attacks many species of wildlife Integrated Pest Management of Red Imported Fire Ant • RIFA is essentially impossible to eradicate in the open and difficult to manage. • Toxic pesticides were initially sprayed over wide areas yielding no significant overall effect but causing massive contamination and side effects. • Current use of pesticides is generally limited to local “mound drench”. • Mounds can be knocked down but are quickly rebuilt. • Biological control methods offer some promise of future management. • RIFA is climate limited but climate warming may expand its potential distribution northward. • RIFA was detected in WA in 1999 in a greenhouse; it was eradicated. ~ fin ~