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 ~