Date of Award

1989

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Entomology

First Advisor

E. A. Heinrichs

Abstract

Six studies were done on feeding and foraging behaviors of three species of subterranean termites, Coptotermes formosanus Shiraki, Reticulitermes flavipes (Kollar), and R. virginicus (Banks) (Isoptera: Rhinotermitidae). When presented with four equal wood blocks, C. formosanus did not forage randomly but concentrated on a few preferred blocks. When R. flavipes and C. formosanus were each placed in foraging arenas with linear, successive wood blocks, C. formosanus consumed a greater percentage dry mass of a wood block before moving to the next block (10.3%) than did R. flavipes (4.2%). Groups of C. formosanus were offered wood blocks that differed in initial moisture content. Wood feeding rate, number of workers, and number of soldiers were highest in the high moisture treatment. Large changes in wood moisture occurred and were affected by the presence of termites. Groups of termites from five colonies of C. formosanus were presented with wood blocks that had been previously damaged: (1) by nestmates, (2) by conspecifics from another colony, (3) by R. virginicus, and (4) no damage. Coptotermes formosanus preferred wood previously damaged by conspecifics, regardless of colony origin, over wood damaged by R. virginicus or undamaged wood. Additionally, they preferred wood damaged by R. virginicus over undamaged wood. Wood surface area (mm$\sp2$) exposed per unit feeding was higher for C. formosanus and R. flavipes than for R. virginicus. Wood surface area was sometimes reduced, rather than increased, as a result of feeding by R. virginicus. Groups of C. formosanus were dyed with 0%, 0.5% or 1% concentrations of the dye, Sudan Red 7B. Dyed termites had lower numbers of symbiotic protozoans, lower feeding rates, and lower survivorship than did non-dyed termites. These studies suggest that toxic baits for remedial control of termites should be placed at areas of strong foraging since termites are predisposed to stay at rewarding sites. Baits should be highly moist. Areas of structures with previous termite damage should be carefully monitored for reinfestation. These species may differ in their roles as wood decomposers. the popular termite marker, Sudan Red 7B, is not totally innocuous to C. formosanus.

Pages

133

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