Social insect
Army ant (Eciton burchelli) soldiers
- C. & S. America
Queen
1 per hive - has longer abdomen & shorter wings than workers; lacks abdominal stripes.
Imported Fire Ants
A few native (virtually harmless) fire ant spp. inhabit the U.S. •Black imported fire ant (Solenopsis richteri) imported to southern U.S. on plant material on ships from S. America (probably Argentina) before 1918. •Red imported fire ant (Solenopsis invicta) imported to Mobile, AL on ships from S. America (probably Argentina) in the1930s. •Both imported species now occur in southern U.S. •Red imported fire ant has expanded its range & replaced black imported fire ant in many areas. •Red imported fire ant is the species that stings most people in the southern U.S. •Imported fire ants bite - then sting while holding on w. mandibles - if not removed, they keep stinging in a circle. •Initially, red imported fire ant colonies had 1 queen each (monogyne colonies) but some now have multiple queens (polygyne colonies).
Termite Colonies:
All termite species are eusocial. •Colonies are unique in having a Queen & a King - only they are allowed to reproduce - determined by pheromones from Queen. •Child Labor - young termites (beginning at 2nd instar) care for very young termites & do this for the rest of their lives. •Engage in "anal trophallaxis" - exchange of fluids from anus to mouth - this transfers symbiotic microorganisms (termites are born without these) that digest wood inside the termite gut. •A few "advanced" termite species have their own cellulase for digesting cellulose in wood. •Colony activities are regulated by pheromones released by the Queen. •Build elaborate mounds. •Destroy wooden structures. •Important decomposers of dead wood (logs, etc.) & vegetation in nature.
Beeswax
Also used by humans (6-7 million pounds/year produced in the USA). •Used in candles, insulation, adhesives, waterproofing agents, cosmetics, as an artistic (easily molded) medium, etc.
Who discovered the waggle damce
Australian animal behaviorist Karl vin Frisch who was co-awarded Nobel prize.
Eusocial Insects:
Bees esp. the (Eurasian) honey bee, Apis mellifera (Order Hymenoptera). •Wasps esp. yellow jackets & others (Order Hymenoptera). •Ants (Order Hymenoptera). •Termites (Order Isoptera). •1 species of thrips (Order Thysanoptera). •A few species of aphids (Order Homoptera).
Social Bees:
Bumble bees build nests in under- ground chambers, often in old rodent burrows. Colonies increase in size during the warmer months to several hundred workers. • Yellow or black hairs (setae) on the abdomen distinguish them from carpenter bees. • Some bumble bees will not sting; others are aggressive and will sting repeatedly. The sting is relatively painful.
DNA sequence data show that the USA (not S. America) is now a source for invasive Red Imported Fire Ants to:
China •Taiwan •Australia •New Zealand
Traits shared by Eusocial Insects:
Cooperative care of offspring. •Reproductive division of labor. •Overlapping generations - allows offspring to grow up and assist their parents in care of young.
Advantages of group living:
Enhanced defense against enemies - some have alarm pheromones also. •For an individual, living in a group reduces the chance of being singled out & eaten. •Division of labor - workers, soldiers, reproductives, etc. - each different form is called a "caste." •Improved chance of raising young - fed by workers & protected by soldiers ("cooperative care") - young are also inside a nest, hive or mound. •Improved chance of finding & securing food by cooperative hunting or scavenging. •Improved exploitation of short-lived food sources - some ants have a caste used solely for storing food ("honeypots" or "repletes"). •Protection from the environment (wind, rain heat, etc.) - inside nests, hives or mounds - some of these are huge - some termite mounds extend > 15 ft below the soil w. underground galleries extending 300 ft. in all directions.
Royal Jelly ("propolis") & Bee Pollen
Used by humans for various putative health benefits. •Usually sold in health food stores.
Why does eusociality work for some insects?
Eusocial Hymenoptera are haplodiploid (=haplodiploidy) ➢Males result from unfertilized eggs & are haploid. ➢Females result from fertilized eggs & are diploid. ➢Females are more related to their sisters (75% shared genes) than to their potential daughters (50% shared genes). ➢Most of these females are workers who help the Queen/colony & also therefore promote their own genes. ➢William D. Hamiliton, an Oxford University Prof. described this process as Kin Selection - he was co-awarded a Nobel prize for this work. ➢A different theory suggests that eusociality developed when stingers developed (ability to kill or repel larger animals).
Mead
Fermented alcoholic form of honey - popular in mideaval Europe - still available though.
Honey Bees Tasks include:
Gathering pollen & nectar. ➢Scouting. ➢Secreting beeswax (from wax glands in abdomen). ➢Building combs (hexagonal conjoined units of wax - "brood cells"). ➢Feeding larvae ("bee bread" to most larvae; "royal jelly" if a new Queen is needed). ➢Removing dead or diseased bees from hive. ➢Guarding the hive entrance. Note: workers have barbed stingers which embed in tissue when used - bees then die - also secrete alarm & recruitment pheromones when they sting - attract additional stinging bees.
COLONY COLLAPSE DISORDER (CCD)
Has appeared in honey bee colonies worldwide - 1st U.S. cases in 2004. Now ~25% of U.S. hives affected. •Worker bees become disoriented & do not return to hive (often die) - hive eventually "collapses." •To supplement U.S. honeybee populations, USDA has recently permitted importation of bees from Australia. •Causes of CCD are unknown. Suggestions: -Parasitic mites -Exposure to pollen from GM crops -Impact of electromagnetic waves from cellphone towers. -Israeli Acute Paralysis (IAP) virus or Wing Deformation Virus (WDV)(specific to honey bees).
Fire ants sting
fire ant stings produce characteristic pustules; scratching may produce secondary infections
Sociality
living in a group of conspecific individuals that exchange information and cooperate with each other (not including mating).
Drone
male bees - ~ 100 per hive - only task is to mate with the Queen & supply her with sperm - this is done during "nuptial flights." Note: Drones do not have stingers & have larger compound eyes than workers & queens.
sting autotomy occurs in worker honey bees
only honey bees, a few tropical bees, and Pogonomyrmex ants (harvester ants) exhibit this adaptation
Eusocial insects also are altruistic
promote the survival of the colony or a colony member over themselves
Yellow jacket and hornet stings
stings of yellowjackets and hornets may produce significant swelling • allergic responses (sting hypersensitivity) to vespid stings are twice as common than those to bee stings
Other social insects (with less organized societies)
subsocial insects: Web-spinners (Order Embioptera ). -live in webs under logs, etc. •Some cockroaches (Order Blattaria) & Earwigs (Order Dermaptera) - some females display maternal behavior. •Some true bugs (Order Hemiptera) - live in groups for protection. •Some beetles (Order Coleoptera), e.g., passalid beetles & carrion beetles. •Some catepillars (Order Lepidoptera) living in webs.
Social wasps: Family Vespidae
yellowjackets and hornets build paper nests in the ground or in trees • colonies may range from <100 to over 100,000 individuals • workers commonly are encountered while scavenging or when nest entrances are disturbed; some species will squirt venom in an intruders eyes when the nest is threatened • these wasps produce a painful sting with effects that may persist for days
Killer bees (=AfricanizedHybridized Bees)
➢Apis mellifera (honey bee) originated in Old World (Eurasia/Africa). ➢Introduced to the New World (the Americas) by European colonists. ➢Subspecies introduced to N. America (in 1622) was Apis mellifera mellifera. ➢To introduce more favorable traits (for humans) into honey bees, different subspecies or strains have been interbred. ➢To regulate or prevent the introduction of bee diseases or parasites, USDA strongly regulates introduction of new strains/subspecies (since 1922).
Hymenoptera Colonies (ants, wasps & bees):
➢Not all members of the Order Hymenoptera are eusocial or even social. ➢All ants (Family Formicidae) are eusocial. ➢Many species of bees & wasps are solitary. ➢All members of the suborder Symphyta (sawflies) are solitary insects although larvae can congregate on foodplants.
What does the waggle present
➢Workers communicate the location & amount of nectar & pollen they have found by dancing in the hive . ➢Others workers follow this dance to learn the location of the nectar source.
Other Honey Bee Products (e.g., sold by Savannah Bee Company)
Honey Body Wash •Honey Body Lotion •Beeswax Lip Balm
Honey
Honey bees make honey from nectar (regurgitated by workers) & store it for energy/food requirements. ➢Pollen (brushed from pollen baskets -"corbicula" - on legs) is also used as an energy source. ➢To make 1 kilogram (2.2 pounds of honey), 130,000 individual loads of nectar are needed (~ 10 million visits to ind. flowers). ➢Humans have kept honey bees for at least 8,000 years to obtain honey. ➢Honey is rich in sugars (esp. glucose & fructose) & vitamins & minerals. ➢Annual honey production in the U.S. is over 100,000 metric tonnes.
Tasks of the queen:
Laying eggs (up to 1,000 per day). ➢Secreting pheromones to control behavior of workers (& prevent them from reproducing) - "Queen substance" (distributed when Queen is groomed). (When colonies are large, some workers may receive insufficient pheromone - they may then start feeding "Royal Jelly" to larvae - these develop into additional Queens - can try to take over the Hive, be killed (by another Queen), or fly away with some of the workers ("swarming") to start a new colony. Note: Queens have unbarbed stingers- do not detach from bee when used - bee survives to sting again.
Eastern tent moth caterpillars
Malacosoma americanum
Disadvantages of group living:
Nests/hives/mounds are easier for predators to locate, e.g., echidnas, aardvarks, ant-eaters, pangolins, honey badgers, ant-birds, bee-eaters. In Africa, honey-guides (birds) eat honey but cannot open bee hives so they lure a honey badger (or human) to a hive. Individuals in eusocial groups sacrifice a lot. Workers forego mating & egg-production & others must risk their lives to protect the colony. Stinging worker honey bees leave part of their abdomen (with stinger) imbedded & later die.
Waggle information
No. of waggles indicates distance ➢Angle of dance (in a circle) indicates angle from sun to food source. ➢Workers compensate for apparent movement of sun with time. ➢Polarized light from sun can be detected through heavy clouds.
Pollination
Probably the most important service for humans by insects. •Honey bees are the most important pollinators. •Pollen grains (male plant gametes) stick to bees visiting flowers. •Pollen is transferred to female plant structures when bees visit other flowers. •Results in fertilization (pollination) and, later, to seed production. •Honey bees are major pollinators for several crops. •Honey bees (in hives) can be "trucked in" for immediate pollination. •Did you know, GSU sprays pesticides on plants & flowers on campus, effectively killing pollinators including honey bees? •Bumble bees (Bombus spp. - have less stable annual colonies) & some solitary bees are also crop pollinators.
Queen mating
Queen can mate w. more than 6 males during nuptial flights - stores their sperm (in her spermatheca) to fertilize eggs - she never mates again - sperm can be stored at least 7 years.
Animals that live together but aren't social
Some other insects live together (they share the same habitat) but are not social, e.g., Springtails (Order Collembola), or moths swarming around a light at night. These are "aggregations."
subsocial insects
Some social insects do not have all 3 of these traits & are called
Some eusocial wasps (Family Vespidae)
Some vespid nests can have more than one queen at a time. Subfamily Vespinae: Yellowjackets & hornets. Subfamily Polistinae: Paper wasps.
Large numbers of honey bee stings can be fatal.
Stings can cause: 1)Local 2)Large local 3)Systemic 4)Toxic 5)Allergic effects. Allergic reactions account for most of the 200+ U.S. annual deaths • 10 stings/kg can kill an animal or human (500 stings for a 110 lb person).
aerial nests
are produced by some vespids, such as the bald-faced hornet, and the European hornet.
Harvester ants (Pogonomyrmex spp.) ants
can form huge colonies in buildings
Driver ant (Dorylus spp.) colonies (= Siafu)
can kill livestock & humans in Africa
pavement ants:
can not break human skin with their stinger
HONEY BEES (Apis mellifera) - used as an example of social insects
3 Types of Individuals (Castes) Workers - most common caste (up to 100,000 per hive) - sterile females - have various tasks - some workers specialize - others graduate to more complicated tasks as they become older.
Bee research
In 1956-57, in a lab. in Brazil, "African" honey bees were interbred with local honey bees. •Resulting bees (Apis mellifera scutellata were more agressive. •Hybrid (killer) bees appeared to reduce pollen collection - bees were released from 26 hives. •Hybridized "killer bees" are more aggressive than other honey bees & cannot be domesticated. •Killer bees have spread from Brazil throughout much of S. & C. America & have entered the southern U.S. (CA, AZ, TX, NM) - plus recent isolated reports from AL, GA, FL & MS. •Humans, pets, livestock & wild animals are killed every year in the U.S. by killer bees.
Paper wasps (Polistes spp.)
are common stinging wasps encountered in the SUS • Nests are often built around buildings • Nests range in size from < 100 to 400 + individuals • Large hibernation swarms may occur in attics and other buildings
