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INSECT SOCIETIES - I

 Return to Entomology schedule

READ: T&J Chap. 4 pp 74-81

REFERENCES:

Aoki, S. 1987. in Animal Societies: Theories and Facts. Ito, et al. eds.Tokyo. Jap. Sci. Soc. pp 53-65.

Anon. 1992. Sociable beetles. Nature 356: 111

Bonabeau, E. et al. 2000. Inspiration for optimization from social insect behaviour. Nature 406: 39-42.

Bonaeau, E. 1997. Self-organization in social insects. Trends In Ecol Evol. 12: 188-193.

Crespi, B. 1992. Eusociality in Australian gall thrips. Nature 359: 724

Duffy, J.E. 1996. Eusociality in a coral reef shrimp. Nature. 381: 512-514.

Foin, T. et al. 1998. Kin selection and social insects. Bioscience. 48: 165-176.

Foster, K. and F. Ratnieks. 2000. Facultative worker policing in a wasp. Nature 407: 692-693.

Harvey, J. et al. 2000. Competition induces adaptive shifts in caste ratios of a polyembryonic wasp. Nature 406: 183-186.

Kirchner, W. and W. Towne. 1994 June. The sensory basis of the honeybee's dance language. Scientific American. 270(6): 74-80.

Michner, C. D. 1974. The Social Behavior of Bees: A Comparative Study. Harvard Univ. Press.Cambridge.

Queller, D. et al. 2000. Unrelated helpers in social insects. Nature 405: 784-787.

Schmid-Hempel, P. 1999. Parasites of Social Insects. Princeton. Princeton U P. 409pp.

Seeley, T. 1997. Honey bee colonies are group-level adaptive units. American Naturalist. 150 supp.: S22-S41.

Thorne, B. 1997. Evolution of eusociality in termites. Annual Review Of Ecology And Systematics. 28: 27-55.

Tschinkel, W. 1998. The reproductive biology of fire ant societies. Bioscience. 48: 593-606.

Robinson, G. 1998. From society to genes with the honeybee. Am Scientist. 86: 456-462.

Wilson, E.O. 1971. The Insect Societies. Cambridge, MA. Harvard Univ. Press.

 

Society - a group of individuals of the same species organized in a cooperative manner

 

Levels of Sociality

  1. Solitary - Carpenter bee, Xylocopa virginica; Colletes thoracicus form aggregations

  2. Subsocial - adults care for young - carrion beetles, bees, etc. widespread in many orders.

    Subsocial I - mother and daughters live in same nest

    Subsocial II - mother and daughters live in same nest and cooperate - seen in thrips and aphids, where "soldiers" guard colonies

  3. Parasocial

    Communal - adults of one generation use a composite nest - halictids, megachilids, andrenids

    Quasisocial - adults of one generation use a composite nest and cooperate in brood care - halicitid bees, spiders

    Semisocial - same as quasisocial but some work and others reproduce (castes) -

  4. Eusocial - coperative brood care, reproductive castes, overlap of generations

Eusociality can be reached via Subsocial II or Semisocial stages

Eusocial groups

  1. Termites, wasps, bees, ants (Wilson 1971)

  2. Aphids (Aoki 1987)

  3. Weevils (Anon. 1992)

  4. Thrips (Crespi 1992)

Thrips

two species of Oncothrips live in galls on Acacia

macropterous foundresses start galls

first offspring are micropterous, mostly female

micros defend gall against invading insects

in experiments, died fighting inquiline Koptothrips

probably donít reproduce

Foundressesí brood of macro adults emerge later and fly off to start new galls next season (one species may reuse gall - one macro daughter stays)

 

Weevils

Austroplatypus incompertus - Australian, similar to thrips, live in wood

One fertile female, ~5 sterile, defend, enlarge galleries

 

Social wasps

Tribe Polistini

Queens overwinter

Nest one or several together; one dominates others, reproduces more

Queens & nestmates rear brood of workers, who hunt insects and feed brood

Males and new queens reared mostly in fall

 

Termites

close relation to roaches

cellulose feeders; build nests in and of cellulose in ground or carton nests in trees

symbiosis with microbes, fungi

all ~2300 species eusocial

sociality evolved from microbe sharing

male and female reproductives; winged - mass mating flights; lose wings; construct cell in ground (Reticulitermes)

mate periodically; colonies may last up to 25yr(?)

female abdomen greatly enlarged (100mm) can lay 1 egg/sec for 24hrs

may have supplemental reproductives in colony

if queen dies, king excretes substance that induces females to reproduce

pseudergates - can transform into reproductives

workers

immature (no eyes, wings, pigments)

male or female in advanced forms

in Reticulitermes, isolated workers can become reproductive

soldiers

may be male or female

highly specialized for defense

Bees

wasps that feed young pollen, nectar, sap, honey

solitary to eusocial

Halictus - sweat bees

mass underground nests

minimal cooperation

little queen/worker dimorphism

if foundress dies, "oligarchy" of daughters lays eggs

Bumble bees

queens start colonies in spring

use old mouse nests, etc.

build wax egg cells and honey pots

puts pollen ball in egg cell

first brood - workers

feed larvae directly or by provisioning

100-400 workers in colony by late summer

males and queens produced and disperse in late summer

Honeybees

perennial colonies

20 - 80,000 workers

collect pollen and nectar, wax

construct brood cells and feed young

royal cells produce new queens and drones - receive special food

colonies reproduce by swarming

primary swarm

old queen leaves with workers

new queens may fight to death on emergence or be driven out

workers urge new queens out on mass mating flights

male explodes on mating

queen may make up to a dozen flights (3-4/day)

after swarms

mated new queens if not killed by the one who remains

Origins of eusociality

kin selection

importance of haplodiploidy - hymenoptera, thrips

produces close relation among daughters

helping queen propagates own genes

parental manipulation of offspring

 

intraspecific competition and nest takeover - soldiers - see papers on termites