Email: r.rosengaus@neu.edu

Phone: 617.373.7032
Fax: 617.373.3724

Location: 306 Mugar Life Sciences
Mail: NU/Biology
         134 Mugar Life Sciences
         360 Huntington Avenue
         Boston, MA 02115 USA

Research Description

My research tries to understand the factors that may have selected for the evolution of termite sociality. I have hypothesized that pathogens and/or parasites may have played important selection forces that favored the evolution of complex insect societies. This evolutionary question is studied by focusing on the adaptations that termites have evolved in order to resist disease. Termites nest, feed and forage in microbially-rich environments and their colonies are composed of thousands of individuals which could easily become infected either through the direct contact with a pathogen or indirectly through the social interactions among nestmates. Yet, in spite the high risks of infection, termites thrive within their nests. What are the means by which these insects cope with disease? What are the costs and benefits of group-living with respect to disease susceptibility and disease resistance? My research has established that termites use several, and often simultaneous mechanisms to reduce the risks of infection, including behavioral, biochemical, immunological and social adaptations. This line of work is then at the interface of evolutionary biology, behavioral and chemical ecology, immunology and genetics. Termites represent an excellent social model system to answer questions about the emerging field of “socioecoimmunology”.

The Rosengaus Lab

Mechanisms of disease resistance in termites
Dampwood termites nest in and feed on decayed wood, which is also colonized by a variety of microorganisms. Many of these microorganisms are pathogenic.

Zootermopsis angusticollis nesting in wood. Age is positively correlated with size. The overlap of several age-cohorts within the nests appears to reduce disease susceptibility.

Behavioral adaptations to resist disease
Termites increase significantly the rate of allogrooming in response to the presence to an entomopathogenic fungus. Other behavioral changes include a "pathogen-alarm" vibratory display that induces absconding of nestmates away from the source of infection. Cannibalism of sick nestmates and the burial of dead nestmates under fecal material are additional common behavioral adaptations of many termite species.

Feces lining termite nests.

Biochemical adaptations to resist disease
Within the biochemical adaptations to resist disease, termites use secretions from their exocrine glands to suppress the growth and development of bacteria and fungi. For example, termite feces has antibiotic properties. Other glandular secretions of termites, thought to have evolved specifically for the purpose of colony defense or foraging, have fungistatic properties. Thus, it appears that such secretions have acquired a secondary function and now provide protection against potential pathogens in addition to their original function.

Physiological adaptations to resist disease
Termites also respond to the risk of infection through cellular and humoral immunity. Termite hemocytes engage in phagocytosis of microlatex beads. The filopodia extensions are characteristic of the phagocytic process.

As part of their cellular immunity termites also engage in the encapsulation of foreign objects, such as invading fungus or nematodes. We have developed a technique that simulates nematode infection by inserting an inert nylon thread implant into the termite’s hemocoel. Encapsulation results from the deposition of melanin on the surface of the invading parasite (see deposits on the two implants below relative to the nylon thread on the left, which was not inserted).

The rates of encapsulation can be quantified by using confocal laser scanning microscopy and estimating the area of melanin coverage on the thread.

Termites also exhibit nodule formation as part of their cellular immunity.

In addition to cellular immunity, termites also have an acquired humoral immune response. Zootermopsis angusticollis nymphs immunized with deactivated bacteria or non-lethal concentrations of fungal conidia have a significantly higher survival following a challenge with active lethal dosages of the pathogen than non-immunized termites. We have also established that the protein banding pattern of termites changes after immunization, with an enhancement of constitutive proteins and/or the production of novel proteins. Currently, we are studying the mechanism by which termite nestmates become socially immunized.

Pathogens and parasites represent important selective forces. By studying the mechanisms of disease resistance in termites, we can provide insights into the ecological and evolutionary constraints that these insects faced as they evolved socially.

We have initiated a systematic sampling and sequencing of Wolbachia within the order Isoptera.   Wolbachia infects a broad range of arthropods, including termites and through the collaboration with Dr. Seth Bordenstein (Marine Biological Laboratory, Woods Hole) we hope to promote the discovery of novel genetic diversity of this endosymbiotic bacterium.

Selected Publications

Journal Papers

Rosengaus, R.B., Traniello, J.F.A., Lefebvre, M.L., and Maxmen, A.B. 2004. Fungistatic activity of the sternal gland secretion of the dampwood termite Zootermopsis angusticollis. Insectes Sociaux 51:1-6.

Pie, M.R., Rosengaus, R.B. and Traniello, J.F.A. 2004. Nest architecture, activity pattern, worker density and the dynamics of disease transmission in social insects. Journal of Theoretical Biology 226(1):45-51.

Rosengaus, R.B., Moustakas, J.E., Calleri, D.V. and Traniello, J.F.A. 2003. Nesting ecology and cuticular microbial loads in dampwood (Zootermopsis angusticollis) and drywood termites (Incisitermes minor, I. schwarzi, Cryptotermes cavifrons). Journal of Insect Science 3:31. (available on line:insectscience.org/3.31)

Traniello, J.F.A , R.B. Rosengaus, and K. Savoie. 2002. Group living enhances immunity in a social insect. Proceedings of the National Academy of Science, USA 99(10):6838-6842.

Rosengaus, R.B. and J.F.A.Traniello. 2001. Disease susceptibility and the adaptive nature of colony demography in the dampwood termite Zootermopsis angusticollis. Behavioral Ecology and Sociobiology 50(6): 546-556.

Rosengaus, R.B., M.L. Lefebvre, and J.F.A. Traniello. 2000. Inhibition of fungal spore germination by Nasutitermes: Evidence for a possible antiseptic role of soldier defensive secretions. Journal of Chemical Ecology 26(1):21-39.

Rosengaus, R.B., M.L. Lefebvre, D.M. Carlock and J.F.A.Traniello. 2000. Socially transmitted disease in adult reproductive pairs of the dampwood termite Zootermopsis angusticollis. Ethology, Ecology and Evolution 12:419-433.

Rosengaus, R.B., J.F.A. Traniello, T. Chen, J.J. Brown and R.D. Karp. 1999. Immunity in a social insect. Naturwissenschaften 86:588-591.

Rosengaus, R.B., M.L. Lefebvre, C. Jordan and J.F.A. Traniello. 1999. Pathogen alarm behavior in a termite: A new form of communication in social insects. Naturwissenschaften 86:544-548.

Rosengaus, R.B., A.B. Maxmen, L. E. Coates and J.F.A. Traniello. 1998. Disease resistance: a benefit of sociality in the dampwood termite Zootermopsis angusticollis (Isoptera: Termopsidae). Behavioral Ecology and Sociobiology, 44:125-134.

Rosengaus, R.B., M.R. Guldin and J.F.A. Traniello. 1998. Inhibitory effect of termite fecal pellets on fungal spore germination. Journal Chemical Ecology 24 (10): 1697-1706.

Rosengaus, R.B., J.F.A. Traniello. 1997. Pathobiology and disease transmission in dampwood termites [Zootermopsis angusticollis (Isoptera: Termopsidae)] infected with the fungus Metarhizium anisopliae (Deuteromycotina:Hypomycetes). Sociobiology 30:185?195.

Traniello, J.F.A., Rosengaus, R.B. 1996. Ecology, evolution, and division of labour in social insects. Animal Behavior, 63:209-213.

Rosengaus R.B., J.F.A. Traniello,.1993. Temporal polyethism in
incipient colonies of the primitive termite Zootermopsis angusticollis: a single multi-age caste. Journal of Insect Behavior, 6:237-252.

Rosengaus R.B., Traniello, J.F.A. 1993. Disease risk as a cost of outbreeding in the termite Zootermopsis angusticollis. Proceedings of the National Academy of Science, USA. 90:6641-6645.

Rosengaus, R.B. 1992. Kinship, social organization, and colony dynamics in the primitive dampwood termite Zootermopsis angusticollis.
Ph.D. Thesis, Boston University, Boston, Ma.

Traniello, J.F.A., Rosengaus, R.B., Levy, C.K. 1985. Single and double isotope labeling of social insect colonies: Gamma-emitting radionuclides as individually identifiable markers. Entomol. Exp. App. 38:87?92.

Rosengaus, R.B., Traniello, J.F.A. 1991. Biparental care in incipient colonies of the dampwood termite Zootermopsis angusticollis Hagen
(Isoptera:Termopsidae). Journal of Insect Behavior, 4:633-647.

Rosengaus, R.B., Traniello, J.F.A., Levy, C.K. 1986. Social transfer, elimination and biological half-life of gamma-emitting radionuclides in the termite Reticulitermes flavipes Kol. Zeitschrift fur angewandte Entomologie, 101:287-294.

Book Chapters

Calabi, P., Rosengaus, R.B. 1988. Interindividual difference based on behavior transition probabilities in workers of Camponotus sericeiventris. In: Interindividual Behavioral Variability in Social Insects. Ed. R. Jeanne. Westview Press. pp. 61-89.

[Back to Top]