Download 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.
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