Rebeca Rosengaus - Academia.edu (original) (raw)

Papers by Rebeca Rosengaus

Insectes Sociaux, 2015

The evolution of insect sociality has likely been shaped by pathogenic pressures. Previous resear... more The evolution of insect sociality has likely been shaped by pathogenic pressures. Previous research has indicated that social interactions among nestmates can ameliorate risks of infection. We hypothesized that proctodeal trophallaxis (anus-to-mouth exchanges of proctodeal fluid) and coprophagy, both common phenomena across termites, result in the passive transfer of immune elicitors, antimicrobial compounds, and/or immune proteins that could render the recipient of these fluids less susceptible to disease. If true, this would represent a prime example of social immunization. Our results show that in Zootermopsis angusticollis, recipients of proctodeal fluid collected from naı ¨ve, control, and vaccinated donors have similar susceptibility to a subsequent Serratia marcescens challenge. However, nestmates feeding on proctodeal fluid from donors injected with sub-lethal dosages of live bacteria were significantly more susceptible to a subsequent challenge. These data indicate unanticipated costs associated with proctodeal trophallaxis when exploiting infectious environments. That termites frequently engage in these exchanges in spite of the heightened survival costs reveals possible evolutionary trade-offs between the nutritional benefits accrued through these exchanges and the risks of disease transmission. This work represents a first attempt to identify the role of proctodeal trophallaxis within a socioimmunological context.

Behavioral Ecology and Sociobiology, 2022

<b>Copyright information:</b>Taken from "Nesting ecology and cuticular microbial... more <b>Copyright information:</b>Taken from "Nesting ecology and cuticular microbial loads in dampwood () and drywood termites (, , )"Journal of Insect Science 2003;3():-.Published online 15 Sep 2003PMCID:PMC524670.Copyright © 2003. Open access; copyright is maintained by the authors.D. isolated from nests (a) and from the cuticule (b) of the dampwood termite (.) and the drywood species (.), (.) and (.).

insectscience.org Nesting ecology and cuticular microbial loads in dampwood (Zootermopsis angusti... more insectscience.org Nesting ecology and cuticular microbial loads in dampwood (Zootermopsis angusticollis) and drywood termites (Incisitermes minor, I. schwarzi, Cryptotermes cavifrons)

Interindividual Behavioral Variability in Social Insects, 2019

2016 International Congress of Entomology, 2016

ABSTRACT Termites have evolved multiple mechanisms to resist disease. Notably, termites and sever... more ABSTRACT Termites have evolved multiple mechanisms to resist disease. Notably, termites and several other soil-dwelling organisms produce and excrete potent antimicrobial compounds, including β(1,3)-glucanases which are known to breakdown glucans, a major component of the bacterial cell envelope and fungal cell walls. The main objectives of this research are to 1) identify β(1,3)- glucanases from Zootermopsis angusticollis via amplification of the gene unitizing 3' RACE and conserved gene regions for subsequent sequencing; and 2) test whether these termite-derived β(1,3)- glucanases have antimicrobial activity against human pathogens. We have identified the protein based on its activity, and have fractioned the termite sample into multiple components via the use of High Performance Liquid Chromatography (HPLC) on a size exclusion (SE) column. Although each sample on its own has no glucanase activity, both the reconstituted HPLC products and certain pairwise combinations of SE-HPLC products re-established activity in chromogenic gels. This suggested that two or more fractions are synergistic. In vitro assays indentified the fractions responsible for the fungistatic activity against Metarhizium anisopliae, a common entomopathogenic fungus. Currently, these fractions are being tested against Candida albicans, a human yeast pathogen. We expect this innovative approach of tapping termite-derived compounds in the control of certain human pathogens to be successful given that these enzymes are environmentally stable and show high potency, having being “fashioned” by natural selection over millions of years.

Proceedings of the Royal Society B: Biological Sciences

Recent research has shown that low genetic variation in individuals can increase susceptibility t... more Recent research has shown that low genetic variation in individuals can increase susceptibility to infection and group living may exacerbate pathogen transmission. In the eusocial diploid termites, cycles of outbreeding and inbreeding characterizing basal species can reduce genetic variation within nestmates during the life of a colony, but the relationship of genetic heterogeneity to disease resistance is poorly understood. Here we show that, one generation of inbreeding differentially affects the survivorship of isolated and grouped termites (Zootermopsis angusticollis) depending on the nature of immune challenge and treatment. Inbred and outbred isolated and grouped termites inoculated with a bacterial pathogen, exposed to a low dose of fungal pathogen or challenged with an implanted nylon monofilament had similar levels of immune defence. However, inbred grouped termites exposed to a relatively high concentration of fungal conidia had significantly greater mortality than outbred grouped termites. Inbred termites also had significantly higher cuticular microbial loads, presumably due to less effective grooming by nestmates. Genetic analyses showed that inbreeding significantly reduced heterozygosity and allelic diversity. Decreased heterozygosity thus appeared to increase disease susceptibility by affecting social behaviour or some other group-level process influencing infection control rather than affecting individual immune physiology.

Parents can invest in their offspring in a context-dependent manner. Parental nutrition, for exam... more Parents can invest in their offspring in a context-dependent manner. Parental nutrition, for example, can influence the size, weight and protein content of eggs and ultimately, their hatching success. Similarly, the pathogenic constraints under which parents develop may foster differential investment in their own offspring. Parental investment theory predicts that parents exposed to pathogenic microbes may increase their fitness by provisioning their eggs with antimicrobial compounds, rendering them less susceptible to disease. This study tests the hypothesis that maternal provisioning exists in the Tobacco Hornworm moth, Manduca sexta and that mothers invest in their progeny differently depending on their own pathogenic history. Female pupae were weighed and randomly assigned to four different treatments: naïve (not injected), controls (saline injected), immunized (injected with heat killed Serratia marcescens) and challenged (injected with a sublethal dose of active S. marcescens)...

The ecological success of social insects can be attributed, in large part, to their remarkable ab... more The ecological success of social insects can be attributed, in large part, to their remarkable ability to cope with infectious microbial organisms. Social insects can deploy numerous strategies against pathogens including behavioral, biochemical and immunological responses. While past research has revealed that social insects can generate immune function, few studies have focused on the immunocompetence during an insect’s early life stages. We hypothesized that larvae of the black carpenter ant Camponotus pennsylvanicus vaccinated with heat-killed Serratia marcescens should be less susceptible to a challenge with an active and otherwise lethal dose of the bacterium. We compared the in vivo benefits of prior vaccination on second and third instar larvae relative to Naïve and Ringer injected controls. Our results show that, regardless of the colony of origin, multiple survival parameters of vaccinated individuals following a lethal immune challenge were significantly higher than those...

The primitive dampwood termite Zootermopsis angusticollis uses vibrational communication to warn ... more The primitive dampwood termite Zootermopsis angusticollis uses vibrational communication to warn nestmates about dangers facing the colony. One mode of vibrational communication is the pathogen alarm response (PAR), in which the termite vibrates in a seizure-like manner warning nestmates of the presence of lethal conidia concentrations of the entomopathogenic fungus Metarhizium anisopliae. A second stereotypical vibrational display involves head-banging behavior (HB) following a nest disturbance. To identify whether these two context-dependent vibrational forms of communication differ in their physical attributes, an accelerometer was attached to the bottom of a Petri dish to record the signals during PAR and HB. Results show that the physical attributes (frequency of pulses, amplitude of the pulse, number of pulses in a train and number of trains in a 10 minute period) differed between the two signals. This represents the first in-depth analysis of the physical and temporal charact...

Journal of Insect Physiology, 2011

Journal of Applied Entomology, 2005

ABSTRACT

Ecological Entomology, 2013

Invasive species have long been associated with biodiversity declines (MEA, 2005), and many invas... more Invasive species have long been associated with biodiversity declines (MEA, 2005), and many invasive species that have devastating effects on native faunas are insects (e.g. Majerus et al., 2006; Brown et al., 2011). Whilst there is good evidence that some invasive insects are drivers of declines of native species (e.g. the alien Harlequin ladybird Harmonia axyridis in the UK; Brown et al., 2011), there is less consensus for some other invasive insect species. The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae) was accidentally introduced into southern USA in the 1930s from South America (Fadamiro et al., 2009). It has subsequently extended its range and is now widespread throughout south-eastern USA. Previous studies have shown that S. invicta is associated with declines in native ants (Stuble et al., 2009). However, fire ants are usually associated with habitat disturbance, leading to an area of contention amongst ant researchers, and leading to the alternative suggestion that these invasive species ‘are “passengers” of human habitat alteration, rather than “drivers” of biodiversity loss’ (King & Tschinkel, 2013a). Untangling these two factors, and understanding whether fire ants are passengers or drivers in native ant declines, is a challenge that merits further research by invasion biologists. A recent paper (King & Tschinkel, 2013a), reported results from an experimental manipulation of fire ants in an undisturbed pine-savannah ecosystem. The authors report little impact of fire ants on native ants even though there was about five fold difference in fire ant abundance across treatments in the first year of the experiment. Thus the authors conclude that preventing habitat disturbance is the most important way of reducing fire ant impacts. Here we report two responses to the paper. In the first response, Stuble et al. (2013) criticise King & Tschinkel’s experiments because there was no treatment where fire ants were completely excluded, there may not have been sufficient time for new species to colonise experimental plots with reduced fire ant abundance, and that threshold effects may result in plots with very low fire ant abundance having detrimental impacts on native ants. Stuble et al. (2013) also highlight other studies which have shown negative effects of fire ants in the absence of habitat disturbance. In reply, King and Tschinkel (2013b) defend their experimental design and conclusions, and support their arguments with evidence that under natural conditions mature colonies of fire ants rarely occur in undisturbed habitats. They agree that there is some evidence showing that where fire ants colonise undisturbed habitats they have a negative effect on native ants, but King and Tschinkel (2013b) argue these examples are of limited importance, especially since these are usually poor quality habitats where overall ant diversity is low. There is clearly more research to be done to determine the importance of habitat disturbance, and whether or not the impacts of fire ants (and indeed, other invasive insect species) are contextspecific. Given global climate change and its accompanying range shifts by insects, the present discussion is relevant, timely and highlights the need for considerable further research if we are to successfully assess the potentially complex impacts of invasive insects.

Biology Letters, 2013

Social insects deploy numerous strategies against pathogens including behavioural, biochemical an... more Social insects deploy numerous strategies against pathogens including behavioural, biochemical and immunological responses. While past research has revealed that adult social insects can generate immunity, few studies have focused on the immune function during an insect's early life stages. We hypothesized that larvae of the black carpenter ant Camponotus pennsylvanicus vaccinated with heat-killed Serratia marcescens should be less susceptible to a challenge with an active and otherwise lethal dose of the bacterium. We compared the in vivo benefits of prior vaccination of young larvae relative to naive and ringer injected controls. Regardless of colony of origin, survival parameters of vaccinated individuals following a challenge were significantly higher than those of the other two treatments. Results support the hypothesis that ant larvae exhibit immune-priming. Based on these results, we can infer that brood care by workers does not eliminate the need for individual-level imm...

The 2008 ESA …, 2008

Monday, November 17, 2008 - 9:23 AM 0507. Fungal pressures within and surrounding nests of the ar... more Monday, November 17, 2008 - 9:23 AM 0507. Fungal pressures within and surrounding nests of the arboreal termite species Nasutitermes acajutlae. Marielle A. Postava-Davignon, postava-davig.m@neu.edu 1 , Claire A. Fuller ...