IMPORTANT POINTS 3rd or 4th most species-rich order. “Membrane-wing”; well developed ovipositor;...
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Transcript of IMPORTANT POINTS 3rd or 4th most species-rich order. “Membrane-wing”; well developed ovipositor;...
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.
HYMENOPTERA
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
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
IMPORTANCE
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.
SYMPHYTA, sawflies
from Borror, Triplehorn & Johnson, 1980from Peterson 1962
lepidopterous caterpillar
single stemma
multiply-segmentedantennae
> 6 prolegs
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
hamuli
velcro-like
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
tongue of a Euglossine bee
honey bee mouthparts
from Snodgrass
Other Features of APOCRITA
Abdomen
propodeum
gaster
petiole
mesosoma
metasoma
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, barbedhoney 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
aphid mummieschalcidoids
Braconid wasp ovipositing into lepidopterous pupae.
Pupae of a parasitoid formed on host’s exterior as larvae exit.
Cynipidae,gall-wasps and parasitoids
some cynipid galls
A parasitoid cynipid ovipositing into a gall made by a gall-making cynipid.
velvet ant (Mutilidae)
cuckoo wasp (Chrysididae)
Charismatic aculeates.“Acule” = “spear”.
Important features of non-parasitic Aculeata
Nests + Larval protection - Requires defense - Energetically expensive - Resource dependent
“Central-place” foragers: Complex behavior, homing ability
Vespidae: yellow jackets, paper wasps:
pests & beneficials
Nest-buildingProvisioning (hunting)Egg-LayingLarval Development
larva
• An important clade within the Hymenoptera• Specialized wasps• Food: nectar & pollen (not predators, as their close relatives)• Coevolved with vascular plants• Pollinaton
Natural WorldAnthropophilic world (agriculture)
More on BEES later…
Red Imported Fire Ant Solenopsis invicta
• Native to the Pantonal, a semi- tropical 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
RIFA range in USA (slightly outdated)
Original introduction, 1920’s
~2008
Typical mode of infestation showing early mound development.
RIFA castepolymorphism
Closely-related colonies may form “super colonies” covering many square miles.
queen
typical RIFA welts & pustules
day 1 ~ 1 week
dense population of RIFA in pasture
A generalist, RIFA attacks many species of wildlife
Integrated Pest Management ofRed 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 ~