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

Papers by Rebeca Rosengaus

Ecology and Evolution, 2020

The traditional view of innate immunity in insects is that every exposure to a pathogen triggers ... more The traditional view of innate immunity in insects is that every exposure to a pathogen triggers an identical and appropriate immune response and that prior exposures to pathogens do not confer any protective (i.e., adaptive) effect against subsequent exposure to the same pathogen. This view has been challenged by experiments demonstrating that encounters with sublethal doses of a pathogen can prime the insect's immune system and, thus, have protective effects against future lethal doses. Immune priming has been reported across several insect species, including the red flour beetle, the honeycomb moth, the bumblebee, and the European honeybee, among others. Immune priming can also be transgenerational where the parent's pathogenic history influences the immune response of its offspring. Phenotypic evidence of transgenerational immune priming (TGIP) exists in the tobacco moth Manduca sexta where first‐instar progeny of mothers injected with the bacterium Serratia marcescens e...

Scientific reports, Jan 26, 2024

Social insect castes (e.g., queens, workers) are prime examples of phenotypic plasticity (i.e., d... more Social insect castes (e.g., queens, workers) are prime examples of phenotypic plasticity (i.e., different phenotypes arising from the same genotype). Yet, the mechanisms that give rise to highly fertile, long-lived queens versus non-reproducing, short-lived workers are not well understood. Recently, a module of co-expressed genes has been identified that characterizes queens compared to workers of the termite Cryptotermes secundus (Kalotermitidae): the Queen Central Module (QCM). We tested whether the QCM is shared in termite species, in which queens gradually develop via early larval and late larval instars, the latter functioning as totipotent workers (linear development). Similar as in C. secundus, gene expression profiles revealed an enrichment of QCM genes in Zootermopsis angusticollis queens, a species from another termite family (Archotermopsidae). The expression of these QCM genes became gradually enriched during development from early larval instars via workers to queens. Thus, our results support the hypothesis of a conserved genetic toolkit that characterizes termite queens with gradual linear development. Our data also imply a strong caste-specific tissue specificity with the QCM signal being restricted to head-prothorax tissues in termite queens. This tissue-specific expression of key aging-related genes might have facilitated the evolution of a long lifespan in termite queens. Eusocial insects are characterized by reproductive division of labor. Within such insect colonies of termites, ants, bees, or wasps, one or a few individuals specialize in reproduction, while workers (and sometimes soldiers) perform all non-reproductive tasks in the colony, such as foraging, brood care, or colony defense. Associated with this division of labor is a striking increase in the longevity of queens (and kings in termites) compared to worker but also solitary insects . How can such a division of labor evolve, and how can different castes develop? Social insect castes are prime examples of phenotypic plasticity, i.e., the expression of different phenotypes from the same genetic background. Within a colony, workers, soldiers, and new reproductives arise due to differential gene expression during ontogeny caused by epigenetic regulations or environmental triggers such as season, differential feeding by nestmates, the presence of predators, or food availability (e.g., ). Within the realm of sociogenomics (sensu 7) , there has been considerable progress in identifying genes and gene networks underlying caste differentiation and caste differences in social Hymenoptera (e.g., ants: 8-10 , bees: 11 , wasps: 12 ; reviewed in , and references therein). These results revealed that genes and gene networks from solitary insect species were co-opted for caste differentiation (reviewed in ) and these genes might be part of a genetic toolkit that underlies the evolution of caste . During social evolution, some of these networks have become uncoupled, and their genes heterochronically (i.e., change in the timing of the expression of genes during development over evolutionary time) expressed between castes. Details seem to differ between species and lineages (e.g., ). However, there are re-current genes and gene pathways that are associated with nutrient sensing (IIS: insulin/insulin-like growth factor 1 signaling; TOR: target of rapamycin pathways), endocrine (juvenile hormone, JH) regulation, and fecundity (vitellogenin/yolk protein) (e.g., ). These genes and molecular pathways have been summarized as the TI-J-LiFe (for TOR/IIS-JH-Lifespan/Fecundity) network which underlies life history traits in insects in general 17 . Strikingly, in social insects, genes linked to chemical communication (e.g., cuticular hydrocarbon/CHC synthesis and perception) seem to be important components of the TI-J-LiFe network as well . Compared to social Hymenoptera, little comparative sociogenomic data exist for termites, most concentrating on the development of soldiers in a handful of species (e.g., reviewed in , with a few studies on termite

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.

Intersection between parental investment, transgenerational immunity, and termite sociality in the face of disease: a theoretical approach

Behavioral Ecology and Sociobiology, 2022

Average bacterial and fungal CFUs ± S

<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 (.).

The role o

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)

Pleometrosis and Polygyny in Ants

Interindividual Behavioral Variability in Social Insects, 2019

Pathogen-induced transgenerational effects in termites

2016 International Congress of Entomology, 2016

Termite ß (1,3)- glucanases; mining antimicrobial compounds for the treatment of human diseases?

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.

The role of pathogenic microbes on the evolution of social immunity in termites: Disease resistance at the colony level

ROSENGAUS RESUBMISSION Electronic Supplemental Material

Differential parental investment in the face of pathogenic pressures: Manduca sexta as an insect model organism

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)...

Friends or Foes: Microbial Community of Termites

Immunocompetent ant larvae: The ontogeny of disease resistance

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...

Temporal and Acoustic attributes of the pathogen alarm response and head banging behaviour in Zootermopsis angusticollis

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

Evaluation of an entomopathogenic fungus, Paecilomyces fumosoroseus (Wize) Brown and Smith (Deuteromycota: Hyphomycetes) obtained from Formosan subterranean termites (Isop., Rhinotermitidae)

Journal of Applied Entomology, 2005

ABSTRACT

Invasive ants-are fire ants drivers of biodiversity loss?

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.